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Wood-Filled Plastics: They Need the Right Additives for Strength, Good Looks, and Long Life
Wood-plastic composites, or WPCs, are already a 1.3-billion-lb market and are growing at 20% annually. That’s big enough to draw increasing attention from additives suppliers to the particular needs of WPC applications in residential decks, railings, fencing, doors, window frames, outdoor spas, and gazebos. Work is also under way on siding and roofing. Suppliers are busy identifying optimum choices of existing additives and developing new ones to give WPCs better physical properties, surface appearance, and long-term durability.
Proper additive choices for WPCs are critical to both performance and processing. Decking products have not proven to be as "maintenance-free" as originally touted. Warpage, splitting, staining, and discoloration problems have surfaced in some cases. As WPCs attempt to move into more structural load-bearing uses, additives that build mechanical strength are an urgent goal. And on the extrusion line, processing additives are essential to achieving both economical line speeds and smooth surfaces without so-called edge tearing.
The most critical areas of additive selection for WPCs are coupling agents, lubricants, and colorants, with chemical foaming agents and biocides not far behind. Selection of specific types for WPCs depends on the base resin. Polyethylene-based wood composites—mainly recycled HDPE—account for 80% of the market. Wood-PVC is 10% to 13% and wood-polypropylene, 8%. Wood-polystyrene accounts for only 1% to 2%.
Coupling for strength
Coupling agents bond the wood fiber to the resin matrix. They boost the flexural strength and stiffness—usually referred to as modulus of rupture (MOR) and modulus of elasticity (MOE), respectively, which are terms used in the lumber industry. Coupling agents also improve dimensional stability, impact resistance, and fiber dispersion, while reducing creep. Added strength is important in railings, stair treads, fencing and in structural applications. But in decking, coupling agents are used mainly to reduce water absorption, which swells the wood fibers near the surface of the board, causing stresses that can lead to cracking.
Coupling agents are especially valuable in polyolefin WPCs because they overcome the incompatibility between the polar wood chemistry and nonpolar resin matrix. In the lead are chemically modified (usually maleated) polyolefins made by grafting maleic anhydride onto the polymer backbone through reactive extrusion. They generally sell for around $1.50/lb and are used at levels of 1% to 2%.
Newer developments in clude chemically modified polyolefins that are not made by grafting, long-chain chlorinated paraffin, and reactive coupling agents for wood-PVC.
Crompton Corp. recently launched Polybond 3029MP, a maleated HDPE in a new smaller particle size—20-mesh micropellet—that’s said to improve dispersion. At 2%, it reportedly can double the flexural and tensile properties of 60% wood in HDPE.
Crompton also has a proprietary maleated PP that reportedly outperforms coupling agents made by reactive extrusion, partly owing to the ability to incorporate higher maleic anhydride (MA) levels. Trials are said to show significantly higher tensile, flexural, and impact strengths with this additive, less susceptibility to lubricant interference, and 40% lower water absorption.
Equistar Chemical offers the Integrate series of maleated PE coupling agents for PE-based composites, plus new maleated PPs for wood-PP. Jim Krohn, business development manager, claims that wood-PE lumber typically shows at least 50% higher MOR and 20% higher MOE with these additives.
DuPont offers MA-grafted Fusabond MB-226D for wood-PE and MD-353D for wood-PP. Tensile strength in wood-HDPE is said to be 200% to 300% higher than uncoupled formulations. DuPont has also developed a new chemistry that replaces grafting with proprietary copolymers made from anhydride-functional monomers that are said to work well in wood-PE.
Eastman Chemical offers Epolene MA-grafted coupling agents such as PE-based Epolene G-2608 and newer PP-based E-43, G-3003, and G-3015 grades. "We have seen a 70% increase in overall tensile properties, 30% to 35% increase in MOR, over 200% in unnotched Izod impact, about 20% improvement in HDT, and dramatic increases in moisture resistance," says business development manager Damon Hollis.
Dover Chemical is offering a long-chain chlorinated paraffin (LCCP) as a non-reactive coupling agent that appears to improve strength retention of HDPE and PP WPCs during moisture cycling. Unlike maleated olefins, which tend to detract from lubrication properties, LCCP reportedly increases lubrication, as well as uv and moisture resistance. According to Dover’s data, the LCCP yields higher flex modulus and tensile strength than a standard zinc stearate/EBS formulation of 60% wood in HDPE; however, the extruder torque was higher with LCCP. But when combined with a proprietary lubricant in a one-pack system (Doverbond DB 4300), both lower torque and higher physicals were achieved. In fact, the lubricated system has higher stiffness and strength than the unlubricated control, unlike the stearate/EBS sample. MOR of PP and HDPE with 60% wood is 40% higher with DB 4300 than with stearate/EBS, adds business manager Tom Kelley. Listing at $1.50/lb, the one-pack can be used at 3% to 5% in place of 1% to 2% of a typical coupling agent plus 3% to 5% of traditional lubricants.
Clariant Additive Masterbatches offers two compatibilizer concentrates. Cesa-mix 8611 is a functionalized copolymer for use in PE and PP, and Cesa-mix 8468 is a highly functionalized system that’s said to improve surface quality of wood-PP. New developments for compatibilizing wood-PVC are in the works at Crompton. The issues are different than with polyolefins because both wood and PVC are polar. "But wood has a lot of acid on the surface that degrades PVC, while PVC generates hydrochloric acid that degrades wood," explains Dr. Peter Frenkel, R&D director for vinyl additives. One solution is to treat the wood fibers with a sizing stabilizer before compounding. Mark W15 is a new, proprietary wood sizing agent that acts both as a compatibilizer and heat stabilizer and significantly improves tensile and flexural strength.
Crompton is also developing a new reactive compatibilizer for wood-PVC. It is designed to be mixed into the PVC matrix to make it compatible with wood fiber and improve properties.
Lubricants are essential
Lubricants increase throughput and improve WPC surface appearance. WPCs can use standard lubricants for polyolefins and PVC, such as ethylene bis-stearamide (EBS), zinc stearate, paraffin waxes, and oxidized PE.
EBS with zinc stearate is widely used in wood-HDPE. However, there are new alternatives because metal stearates are known to decouple the maleic anhydride of maleated coupling agents, canceling the effectiveness of both lubricant and coupling agent. These new lubricants sell for around $1/lb vs. 70¢ to 90¢/lb for EBS and zinc stearate.
WPCs use about twice as much lubricant as standard plastics. For HDPE with a typical 50% to 60% wood content, lubricant level can be 4% to 5%, while a similar wood-PP composite typically uses 1% to 2%. Total lubricant level in wood-PVC is 5 to 10 phr.
Struktol has a new proprietary lubricant package, TPW 104, for wood-polyolefin composites. It contains zinc stearate and therefore is not recommended for use with maleic anhydride coupling agents. Also new is TPW-113, a package with non-metallic lubricant for wood-polyolefins. For wood-PVC, Struktol offers TPW-012 and TR-251 lubricant packages, which combine standard rigid PVC lubricants with some "unique chemistry," says product manager Mike Fulmer.
Lonza Group has developed a more advanced alternative to its standard EBS (Acrawax C) plus zinc stearate. Glycolube WP-2200 is a new proprietary amide lubricant that contains no metallic stearates. It reportedly performed well in wood-HDPE field tests and has potential for wood-PP and wood-PVC composites. Recent trials showed a reduction of overall lubricant use from 4.5% to 3% while delivering over twice the extruder throughput.
Crompton offers fatty-acid-based lubricants for wood-polyolefins. These include metallic stearates, amides, and esters. Lubricants for wood/PVC composites include both internal and external Marklube lubricants.
Clariant Additive Masterbatches offers Cesa-process 9102, a fluoroelastomer for extrusion of wood-polyolefins. Cesa-process 8593 and 8633 are proprietary lubricant systems for wood-polyolefin extrusion. Cesa-process 8477 is a highly loaded fatty-ester system for wood-polyolefin extrusion and injection molding.
Ferro Corp.’s Polymer Additives Div. has developed two new series of lubricants for WPCs. The SXT 2000 series blends metallic stearates with non-metallic lubricants for wood-polyolefins. The SXT 3000 series is totally free of metallic stearates. Although SXT 3000 costs more per pound, it is so effective that it is possible to reduce lubricant loading while still achieving improved throughput and product quality, according to lubricants technical manager Louis Brandewiede. Both lubricant families have shown significant increases in output—up to 50% more than traditional rates.
Reedy International, supplier of Safoam endothermic chemical foaming agents, is offering three new lubricants for foamed WPC composites. Safoam WSD is a lubricant and antioxidant that is applied to the wood flour. It is designed for PP and PVC containing up to 70% wood.
Safoam WLB is a reportedly unique HDPE wax external lubricant for PVC, PP, and HDPE composites. It reportedly allows very low use levels.The third product is a highly branched, ester wax internal lubricant designed to allow the wood fibers to wet out better than with EBS/metal stearate combinations.
Colorants for WPC
Colorants are used to provide both a wood-like appearance and uv resistance. Masterbatch suppliers are using colorfast, highly reflective, and weatherable pigments to satisfy demand for better color-fade resistance at the lowest possible cost. Pigment levels must be 1% to 3% or higher to overcome color staining from the wood. Color concentrates tailored for WPCs typically include lubricant and often are customized multifunctional packages that may include coupling agents, antimicrobials, and uv stabilizers.
Accel Corp., which has been active in WPCs for over 10 years, offers customized color and additive masterbatches for wood-PE and wood-PVC composites.
Ferro’s Plastics Colorants Div. has introduced standard wood-polyolefin colors such as teak brown, cedar, weathered gray, and redwood, as well as custom color matching in concentrates, liquids, and non-dusting granules.
Clariant Masterbatches offers tan, dark red, gray, and oak standard masterbatches, as well as custom colors, for PE, PP, PVC, and PS composites. Colorants are tailored for wood contents from 30% up to 70%.
Techmer PM has introduced redwood, cedar, brown, white, and black- colorants for polyolefin and PVC wood composites.
Chemical foaming grows
There is keen interest in chemical foaming of WPCs to reduce weight and materials cost and to improve surface appearance, processing speed, and ease of sawing, nailing, screwing, and painting finished products. About 20% of all WPC products—mostly wood-PVC—are currently foamed.
Both endothermic and exothermic chemical foaming agents (CFAs) are used. Foaming is tougher for crystalline polymers like PE and PP than for amorphous polymers like PVC and PS, as the latter generally have better melt strength. When higher wood content is added to the mix, as in polyolefin decking products, the challenge is particularly daunting.
Says Bill Crostic, president of wood-polyolefin compounder Onaga Composites, "We see CFAs finding a niche in fence and exterior trim boards and less in decking, where wood content can be as high as 70%." He points out that the more wood is present, the less resin there is to be foamed.
While it’s not easy, Mike Reedy from Reedy International says foaming of higher wood-content WPCs can be done with the right materials, additives, and processing conditions. He cites the example of a new 65%-wood PP composite decking product produced with Safoam CFAs and lubricants on a conical counter-rotating twin-screw extruder. The result is 0.788 g/cc density—30% to 35% lower than unfoamed wood-polyolefins.
Clariant’s Additives Masterbatches Business unit offers the Hydrocerol PLC series of CFAs, which include endothermic, exothermic, and endo-exothermic blends for polyolefin, PVC, and PS wood composites. Says new business development manager Dennis Haff, "People who are using our foaming agents typically have below 50% wood content, which allows for meaningful foaming potential."
Bergen International has seen its Foamasol CFAs used in PVC, polyolefin, and PS wood composites, primarily for decorative moldings such as siding trim boards, railings, and spa panels, where loss of physical properties from foaming is not an issue. "Most of our customers are using wood content in the 20% to 30% range. We aim at weight reduction of 5% to 10%, says president Dennis Keane.
Crompton offers its Celogen family of exothermic CFAs, which can be used to foam wood-polyolefin and PVC composites. Techmer PM has three new standard CFA masterbatches for wood-polyolefins. These are typically custom formulations including color and other additives. The products include exothermic types and endo-exothermic blends with different loadings and decomposition temperatures.
Accel Corp. offers both endothermic and exothermic CFAs, typically in a multifunctional additive and color masterbatch for wood-PE, wood-PVC, and more recently wood-PP decking and fencing.
Combating mold & mildew
Mold, mildew, and stains on some WPC decking are driving manufacturers to consider antifungal biocides that protect either the plastic component and maintain its surface appearance or that preserve the wood component from decay and also reduce moisture absorption. Many products purport to do both.
Weathering and uv radiation have been shown to degrade the surface of WPCs within a few weeks of exposure. "They tend to get lighter after initial installation as the colored extractives and lignin from wood fibers are removed by rain. With continued exposure, loosening of the wood fibers and breakdown of the plastic component follow color change. Also, moisture can lead to a loss in mechanical properties and provide a more favorable environment for fungal growth," explains Gerry Capocci, market manager at Ciba Specialty Chemicals.
Ciba offers Irgaguard F3000, a thiazolyl benzimidazole said to be a broadly effective fungicide for wood-polyolefin and wood-PVC composites. Developmental EB 43-25 combines Irgaguard F3000 with a proprietary additive. It is both a broad-spectrum fungicide and can eliminate or reduce stains due to interactions of iron, tannin, and moisture.
U.S. Borax offers Borogard ZB zinc borate as a preservative for wood-polyolefin and wood-PVC composites. It has broad-spectrum activity against wood-destroying organisms plus heat and uv stability and resistance to leaching and weathering, according to technical manager Mark Manning.
"Laboratory evaluations of commercial WPC products against wood- destroying organisms such as decay fungi and termites have shown weight losses of 10% to 20% in as little as four months, which equates to 20% to 40% weight loss in 50/50 wood-plastic WPCs," says Manning. But when Borogard ZB was added to HDPE decking with 50% to 70% wood, weight loss was less than 1.1%, he reports.
Rohm and Haas sells Vinyzene biocides, which are based on dichloro-octyl-isothiazolone (DCOIT) for wood-PVC composites. Newly commercial Vinyzene SB27 is a concentrate of DCOIT in a vinyl carrier.
The company is also field testing new SB27-ELV, which is 10% DCOIT in a polyolefin terpolymer, aimed at wood-polyolefin composites. This leaching-resistant and uv-stable product is said to be effective at 0.04% to 0.1%.
New developments for treating natural lumber planks also have potential for treating the wood flour used in WPCs to prevent color change. Lonza introduced an alternative to chromium copper arsenic (CCA), a carcinogenic wood preservative banned by the EPA in Dec. 2003. Lonza’s Carboquat is a quaternary ammonium compound that could be used to treat wood flour for WPCs. Ciba also has a new proprietary wood treatment that is ready for sampling. Struktol is working on anti-staining wood lubricants that will neutralize tannins.
Substitute talc for wood?
Replacing some of the wood flour and resin content of wood-HDPE and wood-PP products is a major R&D focus at talc supplier Luzenac America. Trials of HDPE with a 60% filler loading (33% wood/27% talc) reportedly show significant improvement in MOE and MOR, HDT, and creep performance. Throughput increases 15% when 10% of the wood in a formulation is exchanged for talc, Luzenac says. Throughput gains of up to 37% result with a 50% talc-for-wood substitution. Moisture absorption is also much lower.
Brominated flame retardants restrict its use. Most now goes to China, but new recycling processes promise to ‘clean up’ e-waste.
Improved clarity and cost competitiveness, added to its inherent heat resistance, are reviving OPP’s prospects in hot-fill barrier containers. But hot-fill PET containers are raising the bar with higher productivity and ‘panel-less’ bottle designs.
Low-cost wood is still king, but plastics’ reusability is a growing attraction among manufacturers looking for sustainable material-handling options. The one major hurdle is today’s high resin prices.

domain: chemistry


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Why Choose A Handleless Kitchen?
Your kitchen sees a lot of foot traffic throughout its lifetime. From family members rushing to eat breakfast, running around after forgetting something important, or simply wandering from the couch to the fridge and back again! With so many people coming and going, it is essential to keep your kitchen looking stylish and feeling safe. And, with this in mind we have a stylish solution that will add a new level of minimalistic design and safety to your kitchen. Allow us to introduce you to handleless kitchens! Continue reading to discover what handleless kitchens are, how your home can greatly benefit from this contemporary design, and discover answers to the most commonly asked questions about handleless kitchens.
What Is A Modern Handleless Kitchen?
You might imagine cabinets and drawers with silver knobs, large cabinet bar pulls, or cup pull handles when you think of a kitchen. While these choices are popular, they can be seen as clunky, especially if you are trying to achieve a minimalist and sleek appearance. Instead, a handleless kitchen design offers a beautiful yet functional solution if you are looking for a contemporary look that incorporates safety and style.
What Exactly Is a modern handleless kitchen
Well, a handleless kitchen is exactly as it is described; it is a style of kitchen that does not have any protruding knobs or handles on your kitchen doors, drawers and sometimes cabinets. But, don’t worry; you will still be able to get into your cupboards with a handleless solution.
There are different handleless options you can choose from, including a J-pull handle, which is an integrated handle that is hidden from view.
This option will allow you to put your hand in the gap to easily access the hidden handle, and many people opt for this design due to its smooth surface.
Another handleless option which is a rising favourite amongst homeowners is the push open handles, which feature a mechanism where all you have to do is push the door, and the spring will open the door for you. This mechanism is extremely beneficial if you find yourself with your hands too full to open a drawer with a round handle, for example.
Why are handleless kitchens so popular
There is something modern and elegant about handleless kitchens. The style looks sleek and clean while adding a level of warmth and sophistication to your home. But, there are many more reasons why this kitchen design is so popular amongst homeowners, especially families.
The resurgence in this trend is due to homeowners wanting to obtain smooth, modern and sleek looking interiors which are still fully functional. If you are after an effortlessly smooth aesthetic with clean lines and an elegant finish, a handleless kitchen might be perfect for you and your needs.
What are the benefits of a handleless kitchen
Handleless kitchens are also becoming more and more popular in recent years because of the benefits they can bring to your home. While specific benefits depend on person to person, depending on your needs, there are still universal benefits you could take advantage of with this style:-
In years to come, you will be able to look at your handleless kitchen, knowing it is still a timeless and lasting kitchen style. A handleless kitchen is a simple and elegant choice, which is a design investment you will be thankful for, even when other areas of your house may change.
Easy to clean
Aside from the oven, kitchen handles are one of the most annoying things to keep clean, as they get used so often! A handleless kitchen, especially those with push to open cabinets, is easy to clean. No twisting behind pull bar handles is required to remove stubborn food stains, as in most cases, all you have to do is wipe down the cabinet surface.
How often have you had a bad day, and it’s gotten worse because a piece of clothing has snagged on a cabinet handle? Or how many times has your child come crying because they accidentally ran into a protruding kitchen door handle? Too many times to count. One of the key benefits that busy households, especially those with kids, love is that handleless kitchens offer an additional level of safety. Many kitchen cabinet handles are on eye level with toddlers, which makes them a hazard and a point of intrigue for curious minds to pull on, even when they shouldn’t.
There are already many dangerous elements to consider in your kitchen, and a handleless kitchen easily takes away some of those worries with its unobtrusive style.
If you have a set style preference already in mind for your kitchen design, you will be happy to hear that handleless kitchen options are available in most door colours and finishes. This wide selection means you can select the one that is perfect for your kitchen to continue with a sleek and modern appearance.
What is a true handleless kitchen?
A true handleless kitchen has no built-in handle; instead, this contemporary design uses a top rail, or continuous channel, behind the drawers or cabinets, which has enough space for you to slot your finger to pull the kitchen cabinet or drawer open.
Various colours and finishes aren’t the only style options for true handleless kitchens. They are also available in horizontal and vertical planes, which offer a seamless and modern look throughout your kitchen.
Are Handleless Kitchens More Expensive?
Due to the fact that handleless kitchens are a premium feature, they do cost more. This is because the manufacturing process is a lot more technical because they want to get a smooth and fully functional handleless solution. With this high level of specialist craftsmanship and expert installation, the cost may be approx 10-15% higher, but the finished appearance is always worth it!
White Handleless kitchens
If you want one of the most popular and timeless kitchen designs, you should consider the enduring appeal of the white handleless kitchen design. White handleless kitchens are extremely popular because they are so versatile. Perfect as an all white kitchen, or else you can add splashes of colour in the form of a black or wood worktop or choose an elegant and sophisticated vibe by incorporating a marble kitchen island. The possibilities are endless, as you have complete freedom over the type of white handleless cabinetry you install and what you combine those features with to create your dream kitchen.
What is the handleless shaker kitchen
While white handleless kitchens have stayed around for years and will continue to stand the test of time, one design option that is making a dramatic entrance in the market is the handleless shaker kitchen style. A handleless shaker kitchen will bring a modern appeal to a traditional style. The sleek, clean lines and the handleless feature will make your kitchen feel welcoming and balanced.
This kitchen style is great for anyone looking for a traditional style with modern features that will create a timeless appearance.
Thanks to the sleek lines and elegant design, the handleless feature and shaker style naturally complement one another.
Not only will a handleless shaker kitchen look good, but it also provides your kitchen with more space, which is ideal if you have a small kitchen. There will be no protruding cabinet handles to get in your way as you cook and prepare your food. Your kitchen will generally feel more open and welcoming, as there will be no clunky handles to break the balanced appearance.
For those looking for elegance and safety, handleless kitchens will be a popular trend for years to come. The decision of whether or not you want this modern style in your home is entirely up to you. You know your space, how family and friends use your kitchen, and what type of handles would be safe yet functional for everyone concerned. The entire point of designing your kitchen is that you can pick the elements that work well for you and your household. Think about what would make your life easier and what function a handleless kitchen will serve.
Take the next step towards elegance and safety with a luxury handleless kitchen.

domain: design


New consumer research from Leichtman Research Group (LRG) found that 44 percent of TV households in the United States have at least one DVR, and one-third of DVR households have more than one DVR – representing 14 percent of all households having multiple DVRs. In 2005, just 8 percent of all households had a DVR.
In addition, 73 percent of all digital cable subscribers have used VOD, with 87 percent of this group having watched an on-demand program or movie in the past month. Overall, about 62 percent of digital cable subscribers used on-demand in the past month – compared with 52 percent last year.
“On-demand TV viewing in the forms of DVR and VOD, as well as Netflix streaming, have significantly increased in terms of usage and popularity over the past few years,” said Bruce Leichtman, president and principal analyst for LRG. “Yet these on-demand TV platforms remain largely complementary to traditional TV services and viewing, with about 90 percent of all TV viewing in the U.S. still being via live TV.”
Other related LRG findings:
- 80 percent of DVR owners rate the service 8 to 10 (on a scale of 1 to 10, with 10 being excellent) – compared with 80 percent last year and 77 percent two years ago.
- 62 percent of cable VOD users rate the service 8 to 10 – compared with 60 percent last year and 55 percent two years ago.
- 74 percent of premium on-demand (POD) users rate VOD 8 to 10 – compared with 54 percent of non-POD users.
- 63 percent of all Netflix subscribers rate the Watch Instantly feature 8 to 10 (on a scale of 1 to 10, with 10 being an extremely important feature or benefit of the Netflix service) – compared with 48 percent last year and 37 percent two years ago.
- 20 percent of Netflix subscribers use Watch Instantly daily, and 57 percent weekly – last year, 10 percent used Watch Instantly daily, and 43 percent weekly.
- 78 percent of Watch Instantly users use it to watch movies and TV shows on a TV set.
- 86 percent of Netflix households subscribe to a multichannel video service, and 43 percent with a multichannel video service subscribe to a premium service – similar to all households in the sample, and similar to Netflix households last year.


High-resolution spectra of selected rare earth elements and spectral interferences studied by inductively coupled plasma-atomic emission spectroscopy (ICP-AES)
- 化学化工－已发表论文
The rare earth elements (REEs) play very important roles in industrial manufacturing, technology development and biological processes. Due to their complex emission spectra, trace levels of REEs are difficult to analyze by conventional ICP-AES techniques. The present study investigates possible spectral interferences of matrices (rare earth oxides of Ce, Pr, Nd, Sm and Dy) on the analytical lines (+/- 0.1 nm) of a target REE. Detailed and well-resolved spectra for selected REEs are presented, and procedures used to rectify the problem of spectral interferences caused by REE matrices are discussed. A computer-assisted system (GAS) for spectral recognition has been developed and used to assist in the study of matrix interference. To determine directly trace rare earth elements in REE matrices without sample pre-separation, the application potential is demonstrated with a one meter sequential instrument retrofitted with a 3600 grooves/mm grating. (C) 1997 Elsevier Science B.V.


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Pa. governor expresses confidence that accused killer will be found.
More safety accidents at three major research labs are raising concerns about lax oversight.
Experience the Dammann family farm in Iowa through 360-degree video, virtual reality storytelling.
This is the first mission dedicated to studying Mars' upper atmosphere.
Van crashed taking NYPD officers to their work assignment; Williams ejected, killed.
The two men were last seen at the Cape Cod Mall in Hyannis.
The U.S. will not be alone if it strikes the Islamic State in Syria, an official says.
A man jumped over a gate and made it to a White House entrance, Friday.
Police, social workers cooperate to connect people with safe shelter, services.
This TV is one of only two TVs in the world to feature both 4K resolution and OLED tech,
A nurse's incredible act, mother bear's adoption of an outcast cub lead this week's stories.
Feuding presidential candidates in Afghanistan sign a power-sharing deal.
Farm families confront change
The Secret Service is investigating how a man with a knife made it to the White House door.
Farm families confront a nation in transition.
What's the weather where you are? Get the details in today's forecast.
Fire, 60 miles east of Sacramento, grew to more than 128 square miles.
This week's U.N. Climate Summit in New York will be as much about business as politics.
Suspect in deadly ambush has been on the run for nine days.
The impact of such abuse is long lasting.

domain: news


DONG Energy and the UK Carbon Trust, through its Offshore Wind Accelerator
programme (OWA) are planning a major collaborative project. OWA has awarded
DONG Energy GBP 6 million (DKK 54 million) to co-fund full scale demonstration of a new offshore wind turbine foundation called the Suction Bucket Jacket.
The company is aiming to drive down cost of electricity by 40 per cent for projects approved in 2020. Technical innovation in key areas such as foundation is critical to meet this target. The Suction Bucket Jacket was designed by DONG Energy and based on ideas from the SPT Offshore foundation a finalist in a global competition run by the Carbon Trust to find lower cost foundation solutions.
If the demonstration is successful, it could be implemented in future commercial projects from 2017 – including the UK Round 3 projects.
The Suction Bucket Jacket combines jacket technology, consisting of welded tubular space frames, with suction buckets for anchoring the foundation firmly to the seabed.
The bucket foundation (suction caisson) is a well-known concept from the oil and gas industry, where it has been used for more than 30 years for oil platforms installed in the North Sea.
To minimise the time to market for the project, a full-scale prototype of the foundation will be demonstrated with a turbine as quickly as possible. This will allow the performance and stability to be verified. DONG Energy will demonstrate a full-scale Suction Bucket Jacket prototype at the offshore wind farm Borkum Riffgrund 1, where the sandy soil conditions are said to be highly suitable for testing of this new concept. The foundation will be installed in 2014.
The prototype foundation will be installed with a state of the art measurement system that will provide essential data for the verification of the Suction Bucket Jacket concept.
The collaboration will ensure that OWA participants E.ON, Mainstream Renewable
Power, ScottishPower Renewables, Statkraft and Statoil will get full insight into this data, and also have full visibility of the fabrication and installation of the new foundation design.
This will allow them to evaluate whether to use it in the UK.
UK Secretary of State for Energy and Climate Change Edward Davey said: “This project shows that not only is the UK the world’s most attractive destination for investment in offshore wind, we’re at the cutting edge of innovation in the sector.
“Innovations like these bring green jobs to Britain, support wider supply chains and reduce the cost of renewable energy bringing real benefit to consumers.”
Carbon Trust Chief Executive Tom Delay said: “Cutting the costs of offshore wind quickly is the greatest challenge facing the industry over the coming few years. Having identified that lower cost foundations remove significant cost we are delighted to be working with DONG Energy to take this exciting design forward and sharing the concept with other players in the industry.
Vice President at DONG Energy Wind Power, Tove Feld said: “The interest from the Carbon Trust OWA, and the decision to co-fund the full scale demonstration is a great recognition from important developers in the industry of the prospect of this promising new foundation concept. Having more developers utilising the Suction Bucket Jacket will benefit optimisation of design, fabrication process and installation logistics and thereby help to drive down the cost.”
DONG Energy see the OWA as an important part of the joint industry effort to lower the Cost of Electricity for future offshore wind farms. Cooperation within the OWA makes it possible to scope out and deliver larger projects and new solutions within shorter time frames. The Suction Bucket Jacket demo project is a good example of focused industry cooperation, and this would not be possible without the support from the Carbon Trust.
Tailor-made for future demands
This project offers a number of advantages, which will be in demand once offshore wind turbines increase in size beyond 5-6MW and are located in deep water between 30 to 60m. The key benefits are:
- Significant reduction of the foundation cost
- Environmentally friendly installation process
- Negligible noise emission during the installation
- Shorter installation time, decreasing impact on the marine environment
- Usable in a number of soil conditions (e.g. sites with mudstone close to seabed surface)
The project is said to be well suited to the UK supply chain given the UK’s long history of supplying jackets to the offshore wind and the oil and gas industry.
Offshore Wind Accelerator (OWA)


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Frank Lloyd Wright (1867-1959) was an American architect and visionary who left an indelible mark on the field of architecture. His innovative designs, organic principles, and rebellious spirit made him one of the most influential figures in modern architectural history.
Wright’s architectural philosophy was deeply rooted in the belief that buildings should be in harmony with their natural surroundings. He pioneered the concept of “organic architecture,” which sought to create structures that blended seamlessly with the environment, integrating nature and artificial elements. This philosophy is evident in his most famous works, such as Fallingwater and the Guggenheim Museum.
One of Wright’s defining characteristics was his ability to break away from conventional norms and challenge architectural conventions. He rejected the ornate and elaborate styles of his time and instead focused on clean lines, open spaces, and the innovative use of materials. His designs showcased a remarkable balance between simplicity and complexity, harmoniously blending function and form.
Throughout his career, Wright designed over 1,000 structures, including private residences, public buildings, and even entire communities. His iconic Prairie style, characterized by low-pitched roofs, horizontal lines, and open floor plans, revolutionized residential architecture and continues to inspire architects to this day.
Wright’s commitment to innovation extended beyond the aesthetics of his designs. He was a pioneer in integrating technology and sustainability into his work. He experimented with new construction techniques, such as the use of precast concrete and glass curtain walls, and incorporated passive solar design principles to maximize energy efficiency.
Frank Lloyd Wright’s impact on the architectural profession cannot be overstated. His ideas and designs continue to influence architects, designers, and artists around the world. His ability to seamlessly merge the built environment with nature and his relentless pursuit of innovation make him a true icon of 20th-century architecture. As we admire his masterpieces, we are reminded of his timeless legacy and the power of architecture to shape our physical and emotional experiences.
Notable Buildings by Frank Lloyd Wright
Frank Lloyd Wright was an influential American architect known for his innovative and distinctive architectural style. Here is a list of some notable buildings designed by Frank Lloyd Wright:
- Fallingwater (Mill Run, Pennsylvania, USA)
- Solomon R. Guggenheim Museum (New York City, USA)
- Taliesin West (Scottsdale, Arizona, USA)
- Unity Temple (Oak Park, Illinois, USA)
- Robie House (Chicago, Illinois, USA)
- Johnson Wax Headquarters (Racine, Wisconsin, USA)
- Price Tower (Bartlesville, Oklahoma, USA)
- Taliesin (Spring Green, Wisconsin, USA)
- Hollyhock House (Los Angeles, California, USA)
- Marin County Civic Center (San Rafael, California, USA)
- Ennis House (Los Angeles, California, USA)
- Taliesin East (Spring Green, Wisconsin, USA)
- Jacobs House (Madison, Wisconsin, USA)
- Wingspread (Wind Point, Wisconsin, USA)
- Auldbrass Plantation (Yemassee, South Carolina, USA)
- Florida Southern College (Lakeland, Florida, USA) – Multiple buildings on campus
- Kentuck Knob (Chalk Hill, Pennsylvania, USA)
- S.C. Johnson Research Tower (Racine, Wisconsin, USA)
- Taliesin West Drafting Studio (Scottsdale, Arizona, USA)
- Beth Sholom Synagogue (Elkins Park, Pennsylvania, USA)
These are just a few examples of Frank Lloyd Wright’s extensive body of work, which includes residential houses, public buildings, museums, and religious structures. Each building showcases his unique architectural style and his commitment to integrating design with nature.
Mill Run, Pennsylvania, USA
Fallingwater, also known as the Kaufmann Residence, is arguably Frank Lloyd Wright’s most iconic and celebrated architectural masterpiece. Completed in 1937, it is located in the serene setting of Bear Run, Pennsylvania, amidst a forest and spanning over a waterfall.
The architectural design of Fallingwater is a testament to Wright’s philosophy of organic architecture, which seeks to harmonize human habitation with the natural environment. Instead of constructing the house on the edge of the waterfall, Wright ingeniously integrated it into the landscape, seemingly emerging from the rocks and cantilevering over the stream below.
One of the most striking features of Fallingwater is the extensive use of reinforced concrete, stone, and glass. The horizontal lines and cantilevered terraces create a sense of fluidity and balance. The materials used, such as local sandstone and concrete, blend harmoniously with the natural surroundings, blurring the boundaries between the built structure and the landscape.
The design of Fallingwater is characterized by open spaces, interconnected rooms, and an emphasis on natural light. Wright incorporated large, floor-to-ceiling windows that offer breathtaking views of the waterfall and the surrounding forest. The interior spaces flow seamlessly into each other, with few partitions and an open floor plan that encourages a sense of connection with nature.
The central living room of Fallingwater features a massive stone hearth, which anchors the space and provides a sense of warmth and cosiness. The furniture and built-in fixtures were also designed by Wright, showcasing his attention to detail and commitment to a unified design concept.
Wright’s ingenious use of cantilevers is a defining aspect of Fallingwater’s design. The cantilevered terraces extend outward, hovering above the waterfall, creating a sense of weightlessness and defying conventional architectural norms. These cantilevers serve as outdoor spaces for the residents, seamlessly merging indoor and outdoor living.
One of the key principles of organic architecture evident in Fallingwater is the integration of natural elements. The house was built around existing trees, with some even growing through the terraces, further blurring the lines between architecture and nature. The sound of the waterfall permeates the spaces, creating a soothing and tranquil atmosphere.
Fallingwater remains a testament to Frank Lloyd Wright’s genius and his ability to create architectural marvels that transcend time. Its harmonious integration with the natural environment, innovative use of materials, and thoughtful spatial design continue to inspire architects and enthusiasts alike. It stands as a symbol of the possibilities that emerge when architecture embraces nature, and when human dwellings coexist in harmony with the world around them.
Solomon R. Guggenheim Museum
The Solomon R. Guggenheim Museum, located on the Upper East Side of Manhattan in New York City, is an architectural marvel and one of Frank Lloyd Wright’s most iconic creations. Completed in 1959, the museum is renowned for its unique and revolutionary design, which challenged the traditional museum architecture of the time.
Wright’s design for the Guggenheim Museum deviated from the typical box-like structures commonly associated with art museums. Instead, he conceived of an inverted ziggurat, a form that resembles a spiralling nautilus shell. The building rises gradually from the ground, culminating in a grand rotunda at the top. This unconventional design not only reimagined the concept of a museum but also transformed the experience of viewing art.
The exterior of the Guggenheim Museum is characterized by smooth, white concrete, which gives the building a sculptural and futuristic appearance. Its cylindrical shape and gentle curves stand out amidst the surrounding architectural landscape, inviting intrigue and curiosity from passersby.
The interior of the museum is centred around the grand rotunda, which serves as the main exhibition space. A continuous ramp spirals upward from the ground floor, creating a seamless and organic flow between the different levels. As visitors ascend the ramp, they are treated to a gradual unveiling of the artwork displayed along the curved walls. This distinctive design encourages a unique way of experiencing art, allowing visitors to engage with the collection in a continuous, uninterrupted journey.
The natural light that floods the museum is another crucial element of Wright’s design. A large, central oculus at the top of the rotunda bathes the interior in soft, diffused light, eliminating the need for artificial lighting during the day. This creates a serene and contemplative atmosphere, enhancing the connection between the artwork and the viewer.
Wright’s attention to detail is evident throughout the Guggenheim Museum. From the custom-designed display cases and furniture to the carefully selected materials, every aspect of the design was meticulously considered to create a cohesive and immersive experience. The colour palette of the interior is predominantly neutral, allowing the artwork to take centre stage while maintaining a sense of harmony and unity within the space.
The Solomon R. Guggenheim Museum stands as a testament to Frank Lloyd Wright’s visionary approach to architecture. Its groundbreaking design challenged the conventions of museum architecture, emphasizing the integration of art, space, and human experience. Today, it remains an iconic symbol of innovation and serves as a beloved cultural landmark, attracting art enthusiasts from around the world.
Scottsdale, Arizona, USA
Taliesin West, located in Scottsdale, Arizona, is a remarkable architectural masterpiece that served as Frank Lloyd Wright’s winter home, studio, and architectural school. Designed and built by Wright in 1937, it stands as a testament to his vision of organic architecture and his lifelong exploration of harmonizing architecture with its natural surroundings.
The architectural design of Taliesin West seamlessly integrates with the desert landscape, showcasing Wright’s commitment to working with, rather than against, the environment. The buildings appear as an extension of the surrounding hills and rocks, blending into the desert terrain. Wright used native materials such as desert rocks, sand, and timber to construct the structures, further enhancing their integration with the natural surroundings.
The structures at Taliesin West are characterized by low, horizontal lines and organic shapes, reflecting the influence of the desert landscape. The buildings are interconnected, with open courtyards and covered walkways that encourage movement and connection between indoor and outdoor spaces. Wright emphasized the importance of outdoor living, and the design of Taliesin West reflects this philosophy, blurring the boundaries between interior and exterior.
One of the most prominent features of Taliesin West is the use of textile block construction. Wright designed unique geometric patterns for the concrete blocks used in construction, creating a sense of visual interest and texture. These blocks, with their intricate patterns, not only served as structural elements but also played a decorative role, adding depth and character to the buildings.
Taliesin West was designed to take advantage of natural light and ventilation. The large, expansive windows allow abundant natural light to flood the interior spaces, while carefully positioned overhangs and shaded areas help protect the buildings from the intense desert sun. Wright strategically placed the buildings to capture prevailing breezes, promoting natural airflow and passive cooling.
The interiors of Taliesin West reflect Wright’s attention to detail and his belief in the unity of design. He designed the furniture, fixtures, and decorative elements to complement the architectural style. The interiors feature low ceilings, cosy fireplaces, and custom-designed furniture that blend seamlessly with the overall design concept. The spaces are designed to be functional and comfortable while maintaining a sense of harmony with the natural environment.
Taliesin West stands as a testament to Frank Lloyd Wright’s innovative approach to architecture and his ability to create harmonious spaces that coexist with nature. It serves as an enduring legacy of his design philosophy and continues to inspire architects and enthusiasts alike. Today, Taliesin West is not only a historic landmark but also the home of the Frank Lloyd Wright School of Architecture, preserving Wright’s principles and teachings for future generations of architects.
Oak Park, Illinois, USA
Unity Temple, located in Oak Park, Illinois, is a groundbreaking architectural masterpiece designed by Frank Lloyd Wright. Completed in 1908, it is considered one of the most important works of modern architecture and a significant contribution to the Prairie School movement.
The architectural design of Unity Temple reflects Wright’s innovative and visionary approach to space and form. It was commissioned as a Unitarian Universalist church, and Wright sought to create a space that fostered a sense of unity and spiritual connection.
The exterior of Unity Temple is characterized by its strong geometric forms and horizontal emphasis, which are typical of the Prairie School style. The building is composed of reinforced concrete, which was a relatively new and innovative material at the time. Wright’s use of concrete allowed for bold, cantilevered rooflines and expansive, uninterrupted spaces.
The entrance to Unity Temple is marked by a low, sheltering roof supported by massive, concrete pillars. These pillars extend upward, creating a sense of verticality and serving as a visual anchor for the structure. The exterior features simple geometric shapes and restrained ornamentation, emphasizing the unity of the overall design.
The interior of Unity Temple is where Wright’s design truly shines. He conceived the space as a sanctuary for spiritual contemplation, characterized by an open, flowing layout. The main worship area features a central auditorium surrounded by balcony seating, ensuring that every member of the congregation has an unobstructed view of the pulpit.
Wright paid meticulous attention to the play of natural light within Unity Temple. The space is illuminated by a series of skylights and bands of art glass windows, which filter the light to create a serene and ethereal atmosphere. The use of light and shadow adds depth and dimension to the interior, enhancing the overall spiritual experience.
Another distinctive feature of Unity Temple is the integration of functional elements into the design. Wright incorporated spaces for community activities, classrooms, and administrative areas within the building. These spaces were seamlessly integrated into the overall design, fostering a sense of community and practicality.
Unity Temple stands as a testament to Wright’s ability to create innovative and functional architecture that evokes a powerful sense of place and purpose. Its design embodies his principles of organic architecture, where the built environment is integrated with its natural and social context. Today, Unity Temple continues to serve as a place of worship and a cultural landmark, preserving Wright’s legacy and inspiring generations of architects and admirers.
Johnson Wax Headquarters
Racine, Wisconsin, USA
The Johnson Wax Headquarters, located in Racine, Wisconsin, is a striking architectural masterpiece designed by Frank Lloyd Wright. Completed in 1939, it serves as the corporate headquarters for the Johnson Wax Company and stands as a testament to Wright’s innovative and visionary approach to architectural design.
The architectural design of the Johnson Wax Headquarters is characterized by its bold use of curves, geometric forms, and innovative materials. The centrepiece of the complex is the Administration Building, known as the “Great Workroom.” This space features a series of curvilinear columns, called “lily pads,” that support the roof structure and create an open, expansive interior without the need for interior support walls.
The “lily pad” columns are made of precast concrete and are anchored to the floor, rising to form a curved canopy above. This unique structural system allows for large, uninterrupted spaces and provides a sense of openness and unity within the building. The columns taper as they rise, giving the impression of delicate natural forms.
The exterior of the Administration Building is clad in red brick and glass. The continuous bands of windows, known as “Prairie-style ribbons,” wrap around the building, allowing ample natural light to flood the interior spaces. The use of glass not only provides transparency but also creates a visual connection between the interior and the surrounding landscape.
The complex also includes the Research Tower, a tall structure that rises above the Great Workroom. The Research Tower is supported by a reinforced concrete core and features horizontal bands of windows that offer panoramic views of the surrounding area. This vertical element adds a sense of verticality and balance to the overall design of the headquarters.
Wright’s attention to detail is evident throughout the Johnson Wax Headquarters. He designed custom furniture, lighting fixtures, and even the corporate logo for the Johnson Wax Company. The interior spaces feature a harmonious blend of natural materials such as wood, stone, and brick, creating a warm and inviting atmosphere.
The design of the Johnson Wax Headquarters is a testament to Wright’s belief in the integration of nature and architecture. The complex is surrounded by beautiful gardens and landscaped courtyards, blurring the boundaries between the built environment and the natural world. Wright saw the importance of creating a harmonious relationship between the workplace and nature, and the headquarters exemplifies this philosophy.
The Johnson Wax Headquarters remains an iconic example of Wright’s organic architecture and his ability to create functional and aesthetically pleasing spaces. It showcases his innovative use of materials, bold design choices, and commitment to creating buildings that harmonize with their surroundings. Today, the headquarters is a significant cultural landmark and continues to inspire architects and visitors alike.


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Impact of Temperature Relative Humidity and Absolute Humidity on the Incidence of Hospitalizations for Lower Respiratory Tract Infections Due to Influenza, Rhinovirus, and Respiratory Syncytial Virus: Results from Community-Acquired Pneumonia Organization (CAPO) International Cohort Study
Background: Transmissibility of several etiologies of lower respiratory tract infections (LRTI) may vary based on outdoor climate factors. The objective of this study was to evaluate the impact of outdoor temperature, relative humidity, and absolute humidity on the incidence of hospitalizations for lower respiratory tract infections due to influenza, rhinovirus, and respiratory syncytial virus (RSV).
Methods: This was a secondary analysis of an ancillary study of the Community Acquired Pneumonia Organization (CAPO) database. Respiratory viruses were detected using the Luminex xTAG respiratory viral panel. Climate factors were obtained from the National Weather Service. Adjusted Poisson regression models with robust error variance were used to model the incidence of hospitalization with a LRTI due to: 1) influenza, 2) rhinovirus, and 3) RSV (A and/or B), separately.
Results: A total of 467 hospitalized patients with LRTI were included in the study; 135 (29%) with influenza, 41 (9%) with rhinovirus, and 27 (6%) with RSV (20 RSV A, 7 RSV B). The average, minimum, and maximum absolute humidity and temperatur e variables were associated with hospitalization due to influenza LRTI, while the relative humidity variables were not. None of the climate variables were associated with hospitalization due to rhinovirus or RSV.
Conclusions: This study suggests that outdoor absolute humidity and temperature are associated with hospitalizations due to influenza LRTIs, but not with LRTIs due to rhinovirus or RSV. Understanding factors contributing to the transmission of respiratory viruses may assist in the prediction of future outbreaks and facilitate the development of transmission prevention interventions.
Lower respiratory tract infections are the third leading cause of death worldwide (1). Data suggest that influenza and other respiratory viruses are major causes of many of these infections (2, 3). Several of these pathogens are transmitted from person to person or from the environment to person, but a clear understanding of the transmission dynamics of influenza and other respiratory viruses is still evolving. Due to this, predicting transmission and epidemics of these viruses is challenging (4). Climate factors such as temperature, relative humidity and absolute humidity have been shown to impact the transmission of respiratory viruses. However, the influence of each of these factors is still controversial. Some studies suggest that low humidity increases viral stability and transmission of influenza (5, 6) and respiratory syncytial virus (RSV) (7). Lowen and colleagues have also documented varied transmission efficiencies of influenza viruses at different temperatures and relative humidities (8). Conversely, other studies suggest that high humidity may increase the stability of rhinovirus and adenovirus, favoring transmission (9). Most of the data related to climate factors and transmission dynamics of respiratory viruses has been generated from basic science research, ecological studies, and passive disease surveillance (e.g. viral specimens obtained for clinical practice).
The Community-Acquired Pneumonia Organization (CAPO) cohort study is a multicenter, international study of adult hospitalized patients with lower respiratory tract infections (LRTIs), which began in 2001. The database for the CAPO study contains information on over 15,000 patients with CAP from over 40 countries. As part of this ancillary study, consecutive hospitalized patients with LRTIs from all nine adult acute care hospitals in Louisville, KY during three consecutive influenza seasons were enrolled. Each of these patients underwent active surveillance for 12 respiratory viruses upon admission. Combining this dataset with data from the National Weather Service allowed us the unique opportunity to evaluate the role of climate factors at the patient level using active respiratory virus surveillance.
The objective of this study was to evaluate the impact of outdoor temperature, relative humidity, and absolute humidity on the incidence of hospitalizations for lower respiratory tract infections due to influenza, rhinovirus, and RSV.
This was a secondary analysis of the CAPO database. As mentioned previously, this ancillary study of CAPO was a 3-year, prospective study, enrolling consecutive adult hospitalized patients with lower respiratory tract infections (LRTIs) due to influenza during three consecutive influenza seasons. Consecutive adult hospitalized patients with a diagnosis of LRTI were evaluated prospectively from 4 adult hospitals in Louisville, Kentucky during the influenza season 2010/2011, from 8 hospitals during the 2011/2012 season, and in all 9 adult care hospitals in Louisville, Kentucky, during the influenza season 2012/2013. After informed consent was obtained, a nasopharyngeal swab was obtained from each patient for respiratory virus detection. The normal climate of Louisville is classified as a warm, humid, and temperate, with average temperatures during the influenza season of approximately 30F, and average precipitation of 3-4 inches per month during the same season.
Consecutive adult patients with the diagnosis of a lower respiratory tract infection were approached by a study coordinator for inclusion in the study. Upon signing of the consent form, the patient was enrolled and prospectively followed. Over 95% of the residents of Louisville, KY sought care in these nine hospitals under study during the third year of the study (Kentucky Hospital Association, unpublished data), therefore only patients from the third year (2012/2013 influenza season) were included in the present analysis.
Patients with more than one respiratory virus identified from the nasopharyngeal swab were excluded from the analysis.
Human Subjects Protection:
Institutional Review Board approval was obtained at all participating CAPO institutions prior to data collection.
Lower respiratory tract infection (LRTI) was defined as a one sign of acute infection (e.g. subjective/objective fever and/or chills) and 2 new respiratory symptoms (e.g. cough, shortness of breath, change ins sputum production).
LRTI was further stratified as community-acquired pneumonia (CAP), acute exacerbation of chronic obstructive pulmonary disease (AE-COPD), or acute bronchitis (AB).
Community-Acquired Pneumonia (CAP) was defined as the presence of a new pulmonary infiltrate on chest radiograph at the time of hospitalization that was associated with at least one of the following three criteria:
- New or increased cough
- An abnormal temperature (37˚C)
- Leukocytosis, leukopenia, or left shift
Acute Exacerbation of Chronic Obstructive Pulmonary Disease (AE-COPD) was defined as the lack of pulmonary infiltrate on chest radiograph at the time of hospitalization that was associated with at least one of the above three criteria PLUS a history of COPD.
Acute Bronchitis (AB) was defined as the lack of pulmonary infiltrate on chest radiograph at the time of hospitalization that was associated with at least one of the above three criteria, without a history of COPD.
Influenza LRTI was defined if the patient had a Luminex xTAG respiratory viral panel positive for any influenza virus via nasopharyngeal swab.
Respiratory syncytial virus LRTI was defined if the patient had a Luminex xTAG respiratory viral panel positive for any respiratory syncytial virus via nasopharyngeal swab.
Rhinovirus LRTI was defined if the patient had a Luminex xTAG respiratory viral panel positive for rhinovirus via nasopharyngeal swab.
Date of Acquisition of LRTI To calculate the incidence of each virus by week, the following formula was used: ([date of admission to the hospital] – ([number of days with respiratory symptoms prior to hospitalization] +1)). This formula allowed us to approximate the date of acquisition of the etiology of LRTI.
Predictor Variable – The primary predictor variables for the present study were as follows: 1) average absolute humidity per week, 2) minimum absolute humidity per week, 3) maximum absolute humidity per week, 4) average relative humidity per week, 5) minimum relative humidity per week, 6) maximum relative humidity per week, 7) average temperature (degrees Celsius) per week, 8) minimum temperature (degrees Celsius) per week, and 9) maximum temperature (degrees Celsius) per week. Data were gathered from the national weather service, and the absolute humidity in grams/meters3 was calculated with the following formula (T=temperature in degrees Celsius, rh= percent relative humidity):
(6.112 x e^[(17.67 x T)/(T+243.5)] x 2.1674 x rh) \ (273.15+T)
Each of these variables was assigned to a particular patient based on the formula described above for the date of acquisition of LRTI.
Outcome Variables – There were three primary outcome variables in this study: 1) hospitalization due to influenza LRTI, hospitalization due to rhinovirus LRTI, and hospitalization due to RSV LRTI. The impact of each of the nine predictor variables outlined previously was evaluated for each of these three outcome variables by week of acquisition of infection.
Confounding Variables – We evaluated the following potentially confounding variables: age, gender, obesity, risk factors for HCAP, the number of days with respiratory symptoms prior to hospitalization, as well as a history of: COPD, liver disease, renal disease, diabetes, congestive heart failure, and cancer.
Quality Control/Data Management Plan – Trained study coordinators or research associates collected data both from patient interviews/questionnaires, and from medical records. All data were collected on a paper case report form and were subsequently entered into an online case report form. The online system included validators to limit data entry error. Once the case was entered, trained study coordinators and research associates examined each case for abnormal data. Any queries were sent back to the coordinator collecting data for remedy. Once all queries were answered, the data were corrected and finally entered into the online database.
Categorical variables were expressed as frequencies and percentages and were compared between those with and without influenza, with and without rhinovirus, and with and without RSV using Chi-squared or Fisher’s exact tests. Continuous variables were expressed as medians and interquartile ranges or means and standard deviations and were compared between groups using the Mann-Whitney U test or the student’s t-test. P values ≤0.05 were considered statistically significant in all analyses unless otherwise specified.
Poisson regression models with robust error variance were used to model the incidence of hospitalization with a LRTI due to either: 1) influenza, 2) rhinovirus, and 3) respiratory syncytial virus (A and/or B), separately (10). For each of those three outcomes, nine separate models were run, using each of the nine predictor variables listed in the Study Variables section. All models were adjusted for the confounding variables described previously.
P-values of ≤0.05 were considered statistically significant, and R v3.0 was used for all analyses.
A total of 467 hospitalized patients with LRTI were included in the study, 293 with CAP, 126 with AECOPD, and 48 with AB. A total of 135 (29%) patients had influenza, 41 (9%) had rhinovirus, and 27 (6%) had RSV (20 RSV A, 7 RSV B). Baseline patient characteristics and baseline climate data on the day before symptom onset of hospitalized patients with and without LRTIs due to influenza, rhinovirus, and RSV can be found in Tables 1, 2, and 3, respectively.
Table 1 Baseline Patient Characteristics and Climate Data Of Those With And Without Influenza Lower Respiratory Tract Infections
Table 2 Baseline Patient Characteristics and Climate Data Of Those With And Without Rhinovirus Lower Respiratory Tract Infections
Table 3 Baseline Patient Characteristics and Climate Data Of Those With And Without Respiratory Syncytial Virus Lower Respiratory Tract Infections
Fig. 1 Adjusted impact of climate factors on hospitalizations due to influenza virus lower respiratory tract infections (Avg = average; Min = minimum; Max = maximum; AH = absolute humidity; RH = relative humidity; Temp = temperature in degrees Celsius)
Fig. 2 Adjusted impact of climate factors on hospitalizations due to rhinovirus lower respiratory tract infections (Avg = average; Min = minimum; Max = maximum; AH = absolute humidity; RH = relative humidity; Temp = temperature in degrees Celsius)
Fig. 3 Adjusted impact of climate factors on hospitalizations due to respiratory syncytial virus lower respiratory tract infections (Avg = average; Min = minimum; Max = maximum; AH = absolute humidity; RH = relative humidity; Temp = temperature in degrees Celsius)
Fig. 4 Depiction of the correlation between nine climate variables and the weekly influenza incidence rate
During the three seasons, the average weekly absolute humidity was 4.7 grams/m3 (min=2.3 grams/m3; max=9.2 grams/m3), the average weekly relative humidity was 71.1% (min=42.3%; max=85.7%), and the average weekly temperature was 4.3°C (min=-2.3°C ; max=12.7°C).
The adjusted impact of each of the nine climate factors for influenza infection, rhinovirus infection, and RSV infection can be seen in Figures 1, 2, and 3, respectively. The average, minimum, and maximum absolute humidity and temperature variables were associated with hospitalization due to influenza LRTI, while the relative humidity variables were not. Correlations between each of the nine climate factors and the weekly influenza incidence rates are depicted in Figure 4. None of the nine predictor variables were associated with hospitalization due to rhinovirus or RSV.
This study suggests that absolute humidity and temperature on the day before symptom onset are associated with hospitalizations due to influenza LRTIs, but not with LRTIs due to rhinovirus or respiratory syncytial virus during the influenza season. Furthermore, the relative humidity on the day before symptom onset was not associated with hospitalizations due to any of the etiologies evaluated. Although temperature was associated with influenza LRTIs, the protective effects were small compared to those related to relative humidity.
The relationships between climate factors and respiratory virus infection incidence are documented in the literature but most published studies are somewhat limited in their methods and scope (5, 11-43). For example, there are no true incidence studies evaluating this correlation enrolling all hospitalized patients with lower respiratory tract infections in a defined population during a defined time period in the literature. Available clinical data do suggest that influenza virus infections are related to absolute humidity (29), relative humidity(44), and temperature (45). Interestingly, contact transmission of the influenza virus, but not aerosol transmission, may be facilitated in times of high temperature (46) and in the presence of high humidity Rhinovirus has been shown to survive more readily in aerosols as well as on surfaces in the presence of high relative humidity (9, 47). Since droplet and contact are known modes of transmission of this organism, it has been suggested that high humidity may prevent the virus from desiccating thereby prolonging survival on environmental surfaces and subsequently facilitating transmission. (6). Increases in the incidence of RSV infections have been correlated with both low and high relative humidity levels (48, 49). However, rainfall has been associated with RSV incidence in multiple studies, both negatively and positively (7, 50-54).
Various theories behind the association between climate factors and the incidence of respiratory viruses have been proposed. Most of the theories have focused on the low temperature/humidity correlations with influenza virus (8, 42). Both inter-host factors such as viral stability changes, respiratory droplet size, and airflow, as well as host factors such as respiratory secretion production and composition, viral clearance, seasonal nutrition changes, ultraviolet light, and socio-behavioral changes (e.g. close indoor contact) have been described as potential mechanisms (8, 55). Our results suggest that host factors, including socio-behavioral factors may not be primary drivers of respiratory viral epidemics during winter seasons. The climate certainly influences droplet size, host and socio-behavioral factors, but if those factors were related to respiratory viral transmission, similar patterns of association between climate factors and different viruses should be seen. Since only the influenza virus was associated with climate factors, our data suggest that absolute humidity and temperature may affect influenza virus stability, pathogenesis or virulence.
This study has a number of limitations. First, we did not account for indoor climate, which may be different than outdoor climate and could modify viral survival and transmission during the winter months. Second, although we made an attempt to define the date of infection with each virus, it is possible that we have not accurately defined this date, leading to misclassification of climate factors to each patient. Third, we had a relatively small sample size, which makes it difficult to make accurate assessments. Since we enrolled patients only during the influenza season, it is possible that we missed a number of cases of viral lower respiratory tract infections. For example, RSV and rhinovirus may have been circulating at different times of the year leading to biased estimates during the winter season. It is also possible that some patients were misclassified as not having an LRTI due to one of these viruses due to the diagnostic technique used. It is possible that patients arriving to the hospital may already have reduce their respiratory virus to an undetectable level, resulting in misclassification. Finally, since this study was ecological in nature, it is not possible to confirm that each patient was truly exposed to a particular temperature or humidity level, particularly indoor temperature and humidity values, where an individual may spend the majority of their day. Another limitation of this study is the fact that there are no accepted gold standard definitions of any of the LRTIs we evaluated. Because of this, we may have misclassified patients based on various definitions. Due to the relatively small sample size, we were not able to evaluate differences among the three influenza seasons. This could possibly induce bias in the results. We were also not able to evaluate the role of asthma and/or use of inhaled corticosteroids in COPD patients. This may bias the results due to residual confounding.
The major strength of this study is that it is a population-based incidence study of nearly all residents of Louisville, Kentucky requiring hospitalization for a LRTI using active respiratory virus surveillance. Most prior studies largely relied on a patient sample or passive surveillance and attempted to correlate population based climate data with the patient sample. Since we were able to enroll nearly all hospitalized patients with lower respiratory tract infections in Louisville, we are able to reduce the bias inherent in some other studies.
Future studies may consider the both the role of the outdoor and indoor climate on the incidence of respiratory virus infections. The indoor climate, humidity in particular, has been suggested as an important factor in respiratory virus transmission (56). Combining the indoor and outdoor temperature may facilitate the development of more robust predictive models for respiratory virus infections. Furthermore, results of these studies may lead to the development of climate modification interventions to limit viral transmission. Finally, there is a need to further elucidate the mechanisms behind the correlation between low absolute humidity and the pathogenesis and/or virulence of the influenza virus but not other respiratory viruses.
In conclusion, this study adds to the body of evidence that the outdoor climate factors, particularly absolute humidity, are associated with influenza incidence. However, we were not able to demonstrate any impact of climate on the incidence of rhinovirus or respiratory syncytial virus. Understanding factors contributing to the transmission of respiratory viruses may assist in the prediction of future outbreaks and facilitate the development of novel interventions for preventing respiratory viral transmission.
- World Health Organization, “The top 10 causes of death,” 2015 [updated January 2017]. [Online]. Available: http://www.who.int/mediacentre/factsheets/fs310/en/
- B. Müller-Pebody, N. S. Crowcroft, M. C. Zambon, and W. J. Edmunds, “Modelling hospital admissions for lower respiratory tract infections in the elderly in england,” Epidemiology and Infection, vol. 134, no. 06, pp. 1150–1157, 2006.
- T. Wiemken, P. Peyrani, K. Bryant, R. R. Kelley, J. Summersgill, F. Arnold et al., “Incidence of respiratory viruses in patients with community-acquired pneumonia admitted to the intensive care unit: results from the severe influenza pneumonia surveillance (sips) project,” European journal of clinical microbiology & infectious diseases, vol. 32, no. 5, pp. 705–710, 2013.
- J. A. Ramirez, “The challenge of predicting influenza,” Frontiers in microbiology, vol. 2, 2011.
- J. Shaman and M. Kohn, “Absolute humidity modulates influenza survival, transmission, and seasonality,” Proceedings of the National Academy of Sciences, vol. 106, no. 9, pp. 3243– 3248, 2009.
- J. D. Noti, F. M. Blachere, C. M. McMillen, W. G. Lindsley, M. L. Kashon, D. R. Slaughter et al., “High humidity leads to loss of infectious influenza virus from simulated coughs,” PLoS One, vol. 8, no. 2, p. e57485, 2013.
- S. B. Omer, A. Sutanto, H. Sarwo, M. Linehan, I. G. Djelantik, D. Mercer et al., “Climatic, temporal, and geographic characteristics of respiratory syncytial virus disease in a tropical island population,” Epidemiology and infection, vol. 136, no. 10, pp. 1319–1327, 2008.
- A. C. Lowen and J. Steel, “Roles of humidity and temperature in shaping influenza seasonality,” Journal of virology, vol. 88, no. 14, pp. 7692–7695, 2014.
- Y. G. Karim, M. K. Ijaz, S. A. Sattar, and C. M. Johnson-Lussenburg, “Effect of relative humidity on the airborne survival of rhinovirus-14,” Canadian journal of microbiology, vol. 31, no. 11, pp. 1058–1061, 1985.
- G. Zou, “A modified poisson regression approach to prospective studies with binary data,” American journal of epidemiology, vol. 159, no. 7, pp. 702–706, 2004.
- M. L. Bouzas, J. R. Oliveira, K. F. Fukutani, I. C. Borges, A. Barral, W. Van der Gucht et al., “Respiratory syncytial virus a and b display different temporal patterns in a 4-year prospective cross-sectional study among children with acute respiratory infection in a tropical city,” Medicine, vol. 95, no. 41, 2016.
- E. R. Deyle, M. C. Maher, R. D. Hernandez, S. Basu, and G. Sugihara, “Global environmental drivers of influenza,” Proceedings of the National Academy of Sciences, p. 201607747, 2016.
- P. Fagan, C. McLeod, and R. W. Baird, “Seasonal variability of respiratory syncytial virus infection in the top end of the northern territory (2012–2014),” Journal of paediatrics and child health, vol. 53, no. 1, pp. 43–46, 2017.
- A. R. R. Freitas and M. R. Donalisio, “Respiratory syncytial virus seasonality in brazil: implications for the immunisation policy for at-risk populations,” Memórias do Instituto Oswaldo Cruz, vol. 111, no. 5, pp. 294–301, 2016.
- R. Q. Gurgel, P. G. de Matos Bezerra, M. d. C. M. B. Duarte, A. Á. Moura, E. L. Souza, L. S. da Silveira Silva, C. E. Suzuki, and R. B. Peixoto, “Relative frequency, possible risk factors, viral codetection rates, and seasonality of respiratory syncytial virus among children with lower respiratory tract infection in northeastern brazil,” Medicine, vol. 95, no. 15, 2016.
- T. M. Ikäheimo, K. Jaakkola, J. Jokelainen, A. Saukkoriipi, M. Roivainen, R. Juvonen et al., “A decrease in temperature and humidity precedes human rhinovirus infections in a cold climate,” Viruses, vol. 8, no. 9, p. 244, 2016.
- T. Kamigaki, L. Chaw, A. G. Tan, R. Tamaki, P. P. Alday, J. B. Javier, R. M. Olveda, H. Oshitani, and V. L. Tallo, “Seasonality of influenza and respiratory syncytial viruses and the effect of climate factors in subtropical–tropical asia using influenzalike illness surveillance data, 2010–2012,” PloS one, vol. 11, no. 12, p. e0167712, 2016.
- S. Morikawa, U. Kohdera, T. Hosaka, K. Ishii, S. Akagawa, S. Hiroi, and T. Kase, “Seasonal variations of respiratory viruses and etiology of human rhinovirus infection in children,” Journal of Clinical Virology, vol. 73, pp. 14–19, 2015.
- P. D. Shaw Stewart, “Seasonality and selective trends in viral acute respiratory tract infections,” Medical hypotheses, vol. 86, pp. 104–119, 2016.
- N. Sirimi, M. Miligkos, F. Koutouzi, E. Petridou, T. Siahanidou, and A. Michos, “Respiratory syncytial virus activity and climate parameters during a 12-year period,” Journal of medical virology, 2015.
- C. Sloan, M. Heaton, S. Kang, C. Berrett, P. Wu, T. Gebretsadik, N. Sicignano, A. Evans, R. Lee, and T. Hartert, “The impact of temperature and relative humidity on spatiotemporal patterns of infant bronchiolitis epidemics in the contiguous united states,” Health & Place, vol. 45, pp. 46–54, 2017.
- N. Sundell, L.-M. Andersson, R. Brittain-Long, M. Lindh, and J. Westin, “A four year seasonal survey of the relationship between outdoor climate and epidemiology of viral respiratory tract infections in a temperate climate,” Journal of Clinical Virology, vol. 84, pp. 59–63, 2016.
- N. Zhao, G. Cao, J. K. Vanos, and D. J. Vecellio, “The effects of synoptic weather on influenza infection incidences: a retrospective study utilizing digital disease surveillance,” International Journal of Biometeorology, pp. 1–16, 2017.
- S. F. Dowell and M. S. Ho, “Seasonality of infectious diseases and severe acute respiratory syndrome–what we don’t know can hurt us,” The Lancet infectious diseases, vol. 4, no. 11, pp. 704–708, 2004.
- J. Shaman and A. Karspeck, “Forecasting seasonal outbreaks of influenza,” Proceedings of the National Academy of Sciences, vol. 109, no. 50, pp. 20 425–20 430, 2012.
- J. Shaman, V. Pitzer, C. Viboud, M. Lipsitch, and B. Grenfell, “Absolute humidity and the seasonal onset of influenza in the continental us,” PLoS currents, vol. 2.
- J. Shaman, V. E. Pitzer, C. Viboud, B. T. Grenfell, and M. Lipsitch, “Absolute humidity and the seasonal onset of influenza in the continental united states,” PLoS Biol, vol. 8, no. 2, p. e1000316, 2010.
- M. Shoji, K. Katayama, and K. Sano, “Absolute humidity as a deterministic factor affecting seasonal influenza epidemics in japan,” The Tohoku journal of experimental medicine, vol. 224, no. 4, pp. 251–256, 2011.
- D. R. Silva, V. P. Viana, A. M. Müller, F. P. Livi, and P. d. T. R. Dalcin, “Respiratory viral infections and effects of meteorological parameters and air pollution in adults with respiratory symptoms admitted to the emergency room,” Influenza and other respiratory viruses, vol. 8, no. 1, pp. 42–52, 2014.
- J. M. Simmerman, P. Suntarattiwong, J. Levy, R. V. Gibbons, C. Cruz, J. Shaman, R. G. Jarman, and T. Chotpitayasunondh, “Influenza a virus contamination of common household surfaces during the 2009 influenza a (h1n1) pandemic in bangkok, thailand: Implications for contact transmission,” Clinical Infectious Diseases, vol. 51, no. 9, pp. 1053–1061, 2010.
- C. Sloan, M. L. Moore, and T. Hartert, “Impact of pollution, climate, and sociodemographic factors on spatiotemporal dynamics of seasonal respiratory viruses,” Clinical and translational science, vol. 4, no. 1, pp. 48–54, 2011.
- R. P. Soebiyanto, F. Adimi, and R. K. Kiang, “Modeling and predicting seasonal influenza transmission in warm regions using climatological parameters,” PloS one, vol. 5, no. 3, p. e9450, 2010.
- H. Sooryanarain and S. Elankumaran, “Environmental role in influenza virus outbreaks,” Annu. Rev. Anim. Biosci., vol. 3, no. 1, pp. 347–373, 2015.
- V. L. Tallo, T. Kamigaki, A. G. Tan, R. R. Pamaran, P. P. Alday, E. S. Mercado, J. B. Javier, H. Oshitani, and R. M. Olveda, “Estimating influenza outpatients’ and inpatients’ incidences from 2009 to 2011 in a tropical urban setting in the philippines,” Influenza and other respiratory viruses, vol. 8, no. 2, pp. 159–168, 2014.
- J. Tamerius, M. I. Nelson, S. Z. Zhou, C. Viboud, M. A. Miller, and W. J. Alonso, “Global influenza seasonality: reconciling patterns across temperate and tropical regions,” Environmental health perspectives, vol. 119, no. 4, p. 439, 2011.
- J. D. Tamerius, J. Shaman, W. J. Alonso, K. Bloom-Feshbach, C. K. Uejio, A. Comrie, and C. Viboud, “Environmental predictors of seasonal influenza epidemics across temperate and tropical climates,” PLoS Pathog, vol. 9, no. 3, p. e1003194, 2013.
- J. W. Tang and T. P. Loh, “Correlations between climate factors and incidence-a contributor to rsv seasonality,” Reviews in medical virology, vol. 24, no. 1, pp. 15–34, 2014.
- D. E. te Beest, M. van Boven, M. Hooiveld, C. van den Dool, and J. Wallinga, “Driving factors of influenza transmission in the netherlands,” American journal of epidemiology, p. kwt132, 2013.
- S. Towers, G. Chowell, R. Hameed, M. Jastrebski, M. Khan, J. Meeks, A. Mubayi, and G. Harris, “Climate change and influenza: the likelihood of early and severe influenza seasons following warmer than average winters,” PLOS Currents Influenza, 2013.
- S. P. van Noort, R. Águas, S. Ballesteros, and M. G. M. Gomes, “The role of weather on the relation between influenza and influenza-like illness,” Journal of theoretical biology, vol. 298, pp. 131–137, 2012.
- W. Yang, S. Elankumaran, and L. C. Marr, “Relationship between humidity and influenza a viability in droplets and implications for influenza's seasonality,” PloS one, vol. 7, no. 10, p. e46789, 2012.
- W. Yang and L. C. Marr, “Dynamics of airborne influenza a viruses indoors and dependence on humidity,” PloS one, vol. 6, no. 6, p. e21481, 2011.
- T. ˙Zuk, F. Rakowski, and J. P. Radomski, “Probabilistic model of influenza virus transmissibility at various temperature and humidity conditions,” Computational biology and chemistry, vol. 33, no. 4, pp. 339–343, 2009.
- J. W. Tang, F. Y. Lai, P. Nymadawa, Y.-M. Deng, M. Ratnamohan, M. Petric, T. P. Loh, N. W. Tee, D. E. Dwyer, I. G. Barr et al., “Comparison of the incidence of influenza in relation to climate factors during 2000–2007 in five countries,” Journal of medical virology, vol. 82, no. 11, pp. 1958–1965, 2010.
- S. M. Firestone, N. Cogger, M. P. Ward, J.-A. L. Toribio, B. J. Moloney, and N. K. Dhand, “The influence of meteorology on the spread of influenza: survival analysis of an equine influenza (a/h3n8) outbreak,” PloS one, vol. 7, no. 4, p. e35284, 2012.
- A. C. Lowen, J. Steel, S. Mubareka, and P. Palese, “High temperature (30 c) blocks aerosol but not contact transmission of influenza virus,” Journal of virology, vol. 82, no. 11, pp. 5650–5652, 2008.
- S. A. Sattar, Y. G. Karim, V. S. Springthorpe, and C. Johnson-Lussenburg, “Survival of human rhinovirus type 14 dried onto nonporous inanimate surfaces: effect of relative humidity and suspending medium,” Canadian journal of microbiology, vol. 33, no. 9, pp. 802–806, 1987.
- C.-S. Khor, I.-C. Sam, P.-S. Hooi, K.-F. Quek, and Y.-F. Chan, “Epidemiology and seasonality of respiratory viral infections in hospitalized children in kuala lumpur, malaysia: a retrospective study of 27 years,” BMC pediatrics, vol. 12, no. 1, p. 32, 2012.
- J. Rechsteiner, “Inactivation of respiratory syncytial virus in air,” Antonie van Leeuwenhoek, vol. 35, no. 1, pp. 238–238, 1969.
- P. W. Chan, F. T. Chew, T. N. Tan, K. B. Chua, and P. S. Hooi, “Seasonal variation in respiratory syncytial virus chest infection in the tropics,” Pediatric pulmonology, vol. 34, no. 1, pp. 47–51, 2002.
- M. P. Loscertales, A. Roca, P. J. Ventura, F. Abacassamo, F. Dos Santos, M. Sitaube, C. MenÉndez, B. M. Greenwood, J. C. Saiz, and P. L. Alonso, “Epidemiology and clinical presentation of respiratory syncytial virus infection in a rural area of southern mozambique,” The Pediatric infectious disease journal, vol. 21, no. 2, pp. 148–155, 2002.
- P. E. Reese and N. J. Marchette, “Respiratory syncytial virus infection and prevalence of subgroups a and b in hawaii.” Journal of clinical microbiology, vol. 29, no. 11, pp. 2614–2615, 1991.
- S. E. Robertson, A. Roca, P. Alonso, E. A. Simoes, C. B. Kartasasmita, D. O. Olaleye, G. N. Odaibo, M. Collinson, M. Venter, Y. Zhu et al., “Respiratory syncytial virus infection: denominator-based studies in indonesia, mozambique, Nigeria and south africa,” Bulletin of the World Health Organization, vol. 82, no. 12, pp. 914–922, 2004.
- M. W. Weber, E. K. Mulholland, and B. M. Greenwood, “Respiratory syncytial virus infection in tropical and developing countries,” Tropical Medicine & International Health, vol. 3, no. 4, pp. 268–280, 1998.
- N. Pica and N. M. Bouvier, “Environmental factors affecting the transmission of respiratory viruses,” Current opinion in virology, vol. 2, no. 1, pp. 90–95, 2012.
- T. H. Koep, F. T. Enders, C. Pierret, S. C. Ekker, D. Krageschmidt, K. L. Neff, M. Lipsitch, J. Shaman, and W. C. Huskins, “Predictors of indoor absolute humidity and estimated effects on influenza virus survival in grade schools,” BMC infectious diseases, vol. 13, no. 1, p. 71, 2013.
Wiemken, Timothy L.; Mattingly, William A.; Furmanek, Stephen P.; Guinn, Brian E.; English, Connor L.; Carrico, Ruth; Peyrani, Paula; and Ramirez, Julio A.
"Impact of Temperature Relative Humidity and Absolute Humidity on the Incidence of Hospitalizations for Lower Respiratory Tract Infections Due to Influenza, Rhinovirus, and Respiratory Syncytial Virus: Results from Community-Acquired Pneumonia Organization (CAPO) International Cohort Study,"
The University of Louisville Journal of Respiratory Infections: Vol. 1
, Article 7.
Available at: https://ir.library.louisville.edu/jri/vol1/iss3/7
Table 1: Baseline Patient Characteristics and Climate Data Of Those With And Without Influenza Lower Respiratory Tract Infections
jri010-Table_2.png (92 kB)
Table 2: Baseline Patient Characteristics and Climate Data Of Those With And Without Rhinovirus Lower Respiratory Tract Infections
jri010-Table_3.png (91 kB)
Table 3: Baseline Patient Characteristics and Climate Data Of Those With And Without Respiratory Syncytial Virus Lower Respiratory Tract Infections
jri010-Fig_1.pdf (5 kB)
Fig. 1: Adjusted impact of climate factors on hospitalizations due to influenza virus lower respiratory tract infections (Avg = average; Min = minimum; Max = maximum; AH = absolute humidity; RH = relative humidity; Temp = temperature in degrees Celsius)
jri010-Fig_2.pdf (5 kB)
Fig. 2: Adjusted impact of climate factors on hospitalizations due to rhinovirus lower respiratory tract infections (Avg = average; Min = minimum; Max = maximum; AH = absolute humidity; RH = relative humidity; Temp = temperature in degrees Celsius) Fig.
jri010-Fig_3.pdf (5 kB)
Fig. 3: Adjusted impact of climate factors on hospitalizations due to respiratory syncytial virus lower respiratory tract infections (Avg = average; Min = minimum; Max = maximum; AH = absolute humidity; RH = relative humidity; Temp = temperature in degrees Celsius)
jri010-Fig_4.pdf (37 kB)
Fig. 4: Depiction of the correlation between nine climate variables and the weekly influenza incidence rate
jri010-Table_1-thumbnail.png (72 kB)
jri010-Table_2-thumbnail.png (70 kB)
jri010-Table_3-thumbnail.png (62 kB)
jri010-Fig_1-thumbnail.png (16 kB)
jri010-Fig_2-thumbnail.png (16 kB)
jri010-Fig_3-thumbnail.png (17 kB)
jri010-Fig_4-thumbnail.png (86 kB)
Community Health and Preventive Medicine Commons, Epidemiology Commons, Health Information Technology Commons, Influenza Humans Commons, Influenza Virus Vaccines Commons, International Public Health Commons, Translational Medical Research Commons

domain: biology


text:
Sharpening its differences with the United States on environmental policies, the European Community proposed today that a high energy tax be imposed on all forms of fuel to limit pollution and global warming.
The proposal, which is one of the community's most ambitious fiscal and environmental moves so far, appears to be intended as the calling card the 12-nation group will present at the Earth Summit meeting in Rio de Janeiro next month.
So far, the step takes the form of a recommendation by the community's Brussels-based executive commission and will require approval by the 12 community member nations as well as the European Parliament before it becomes law.
But, suggesting that the proposal may also be used as a bargaining position at the Earth Summit, the commission proposed that the new tax only be adopted if Western Europe's major trading partners -- the United States and Japan -- adopt a similar measure.
Under the proposal, European governments would levy a tax on fossil fuels -- coal, oil and gas -- and all other forms of energy except that produced by sun, waves or wind. It would be introduced in 1993 at the rate of $3 per barrel of oil, or its equivalent in other fuels, with the tax rising by $1 per year to reach $10 in the year 2000.Continue reading the main story
By driving up fuel costs, the plan aims to force users to become more efficient and save energy, one of the main objectives of the current European rethinking of its economic and industrial policies. Community studies argue that with existing technology, energy efficiency can be increased at little extra cost by 25 percent. The proposed taxes will be highest for the dirtiest form of energy, coal, followed by oil. Taxes on natural gas would be the lowest and biomass fuel would be exempted.
The proposal, which has been studied and debated for more than two years, forms the basis of the community's strategy to slow pollution and global warming. The group has committed itself to keeping emissions of gases tied to global warming at 1990 levels. The United States has balked at setting such targets, which has caused a longstanding deadlock between American and European negotiators preparing a treaty to slow global warming.
If the European Community takes no measures, experts say that its emissions of carbon dioxide, the main greenhouse gas, would be 12 percent higher by the year 2000. It hopes to achieve half of the needed cutback through the proposed "energy taxes" and the rest through other measures. The community is responsible for 13 percent of of global carbon dioxide emissions.
But the plan, formally announced in Strasbourg today, was unlikely to satisfy everyone. There has been bitter opposition from industrialists who assert that such additional taxes will hamper their competitiveness. That was the main reason why the community executive today said the tax would not be levied until major trading partners took the same step.
Officials said that would increase pressure on the United States, Japan and others to accept concrete measures to limit their emissions. But privately, officials said environmental ministers and politicians would press hard for the European Community to adopt their plan even if others did not make such moves.Continue reading the main story


text:
Marriage takes place at a young age, usually in the teens, and most Puerto Ricans desire children shortly after marriage.
Both marriage and the birth of children are important events in terms of forming bonds between families and households, with well-established visiting patterns among related households and compadrazgo relations formed between households at the baptisms of children. The Puerto Rican diaspora has had a strong influence on the character of the domestic unit.
In Puerto Rico, the typical unit consists of a woman and man and their unmarried children, yet it is not uncommon for unmarried or widowed parents to live with their children, and visiting patterns among households and dwellings are such that the lines between households often become blurred.
On the mainland, there is a much higher incidence of households headed by women with small children than there is on the island. In principle, all possessions of the deceased are to be divided into three equal parts: the legitimá (legitimate), which is divided equally among the children; the mejora (best), which is divided among the children according to the decisions of the deceased; and the libre disposición (freely disposable), which is given to the spouse.
Interdependent groups of individuals residing in a number of different locations characterize most Puerto Ricans' domestic units.
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Households may or may not be units bounded by dwellings, plots of land, or even the boundaries of the commonwealth.
The 1990 census reports 3.31 persons per household in Puerto Rico, a figure that is probably an underestimate because of the dispersed nature of Puerto Rican households.
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domain: sociology


text:
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domain: health