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International Journal of Optics
Volume 2012 (2012), Article ID 159057, 14 pages
Nonlinear Pulse Shaping in Fibres for Pulse Generation and Optical Processing
1Photonics Research Group, School of Engineering and Applied Science, Aston University, Birmingham B4 7ET, UK
2Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS, Université de Bourgogne, 21078 Dijon, France
Received 16 November 2011; Accepted 9 January 2012
Academic Editor: Juan Diego Ania Castañón
Copyright © 2012 Sonia Boscolo and Christophe Finot. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
The development of new all-optical technologies for data processing and signal manipulation is a field of growing importance with a strong potential for numerous applications in diverse areas of modern science. Nonlinear phenomena occurring in optical fibres have many attractive features and great, but not yet fully explored, potential in signal processing. Here, we review recent progress on the use of fibre nonlinearities for the generation and shaping of optical pulses and on the applications of advanced pulse shapes in all-optical signal processing. Amongst other topics, we will discuss ultrahigh repetition rate pulse sources, the generation of parabolic shaped pulses in active and passive fibres, the generation of pulses with triangular temporal profiles, and coherent supercontinuum sources. The signal processing applications will span optical regeneration, linear distortion compensation, optical decision at the receiver in optical communication systems, spectral and temporal signal doubling, and frequency conversion.
The use of photonic technologies for data processing in the all-optical domain has a strong potential for a variety of interesting applications in such diverse areas as optical telecommunications, metrology, optical sensing, microwave engineering, advanced microscopy image processing, optical computing, and many others. Advantages of processing the information in the all-optical domain include the large available bandwidth and the (potential) parallelism intrinsic to the optical approach, which translate into high-processing speeds. However, today electronic techniques of signal manipulation are advanced compared to all-optical processing devices, which are still at the research stage rather than under commercial development. A key feature of electronics, enabling many different applications, is the capability of generating electrical waveforms with arbitrary temporal profiles by use of simple integrated circuits. This capability is so far unmatched in the optical frequency range, where bulky and complex devices are required to shape the light fields. Hence, considerable knowledge still has to be accumulated and new methodologies need to be explored before a true breakthrough can be achieved in this field, allowing the range of functions and operations currently accomplished electronically, to be performed in the optical domain. Furthermore, by using optical rather than electronic processing additional functionality may be possible.
In order to realize such all-optical processing, nonlinear photonics is seen as a key technology. Optical fibre materials exhibit a nonlinear response to strong electric fields, such those of optical signals confined within the small fibre core. In high-speed optical communications such nonlinear effects generally degrade the integrity of the transmitted signal but the same effects can be used to realize a variety of optical functions that have practical applications in the field of lightwave technology. In this paper, we provide a snapshot of recent results and advances in the use of nonlinear effects in optical fibres for optical waveform generation and pulse shaping and in the applications of advanced pulse profiles in all-optical signal processing. We would like to note that the main attention in this paper will be focused on results obtained in our groups, and that it is not our intention here to comprehensively cover all the possible examples of fibre-based pulse shaping and signal processing.
2. Fibre Nonlinearities
The third-order optical nonlinearity in silica-based single-mode (SM) fibres is one of the most important effects that can be used for all-optical signal processing. This happens not only because the third-order nonlinearity provides ultra-fast response times in the femtosecond range, but also because it is responsible for a wide range of phenomena such as third-harmonic generation, nonlinear refraction (Kerr nonlinearity), and stimulated Raman and Brillouin scattering . The rapid recent developments of microstructured fibres with extremely small effective core areas and exhibiting enhanced nonlinear characteristics  and of fibres using materials with refractive indexes higher than that of the silica glass  have enabled dramatic reduction of the required fibre lengths for nonlinear processing compared to conventional fibres. Such progress has paved the way for the integration of fibre-based nonlinear processing functions on photonic chips.
The intensity dependence of the refractive index of a fibre gives rise to different effects depending on the shape of the input signal; the most widely studied effects are self-phase modulation (SPM) and cross-phase modulation (XPM). Considering the localized optical pulse evolution in a fibre medium and neglecting higher order effects in the fibre, pulse propagation can be described by the nonlinear Schrödinger (NLS) equation : where is the slowly varying pulse envelope in the comoving system of coordinates, and are the respective group-velocity (second-order) dispersion (GVD) and Kerr nonlinearity coefficients of the fibre, is the nonlinear-index coefficient, the central wavelength of the pulse, and the effective core area. As a result of the nonlinear term in (1), upon propagation in the fibre the pulse acquires an intensity-dependent nonlinear phase shift as , namely, the frequency chirp . When the length scale associated with the pulse where the GVD effects take place: (with being some temporal characteristic value of the initial pulse) is much larger compared with both the fibre length and the nonlinear length (with being the peak power of the initial pulse), the dispersive term in (1) can be neglected. In this case, the presence of a chirp causes a nonlinear broadening of the pulse spectrum. When two (or more) pulses copropagate inside a fibre, one still obtains an NLS equation for each pulse but these equations are coupled through XPM . In this case, the nonlinear phase evolution for each pulse depends also on the power of the other pulses according to the expression . XPM occurs only when the pulses overlap. Similar to the SPM case, XPM leads to additional nonlinear chirping and spectral shaping.
When the effects of chromatic dispersion are considered in combination with the Kerr nonlinearity, rich pulse dynamics arise from the interplay between dispersive and nonlinear effects depending on the sign of the dispersion and the relative magnitudes of the associated length scales. A well-known and fascinating example is the formation of optical solitons [5, 6] in the anomalous dispersion regime of a fibre () as a result of a cooperation between GVD and SPM. On the contrary, in the regime of normal dispersion pulse dynamics are highly affected by the phenomenon of optical wave breaking [7–9].
In the next Section we will discuss some newly emerged qualitative features of the optical pulse evolution in a fibre under the combined action of dispersion and nonlinearity.
3. Optical Pulse Generation and Shaping Using Fibre Nonlinearities
Techniques for generating, controlling, manipulating, and measuring ultrashort optical pulses and specialized waveforms have become increasingly important in many scientific areas including, amongst others, ultrahigh-speed optical communications , optical signal processing, and biophotonics. To date, conventional picosecond and femtosecond pulse shaping in the optical domain have been implemented using devices, such as liquid crystal spatial light modulators [11, 12], wavelength-to-time mapping [13, 14], acoustooptic modulators, and electrooptical phase arrays, that impart user-specified spectral amplitude and phase to the pulse. Though powerful and flexible, this approach has the drawback of requiring a rather bulky and expensive apparatus, entailing a level of cost and complexity that is not often commensurate to the used laser system and target application. In order to fulfill telecommunication requirements, more compact techniques for pulse shaping have been developed, which include the use of super-structured fibre Bragg gratings , long-period fibre grating filters , and arrayed waveguide gratings that are well suited for line by line processing of high-repetition periodic pulse shapes [17, 18]. However, in all these pulse shapers using linear techniques, the bandwidth of the input pulse determines the maximum bandwidth of the output. Indeed, a linear manipulation cannot increase the pulse bandwidth, and so to create shorter pulses nonlinear effects must be used. This limitation of the linear approaches becomes very stringent when synthesizing advanced pulse shapes such as rectangular pulses, for which a large optical bandwidth is required to reproduce accurately the spectral side lobes linked to the temporal compactness of the pulse. Moreover, in those applications that require spectral narrowing, linear filtering introduces a power penalty that is at least proportional to the ratio of the target spectrum to the input one.
The combination of third-order nonlinear processes and chromatic dispersion in optical fibres can provide efficient new solutions to overcome the aforementioned limitations. The pulse-shaping examples discussed below highlight some of the advantages offered by a passive, all-optical nonlinear fibre-based approach to pulse shaping.
3.1. Ultrahigh Repetition Rate Pulse Train Generation
As a first illustration of the possible nonlinear pulse shaping mechanisms in optical fibres, we review here the generation of ultrashort pulse trains with very high repetition rates resulting from the passive evolution of optical pulses in an anomalously dispersive fibre in the presence of Kerr nonlinearity. As mentioned in the previous Section, in the anomalous GVD regime of a fibre, the NLS equation (1) admits families of soliton solutions. While fundamental solitons are characterized by an exact balance between the GVD and SPM effects (), in the case of higher order solitons () SPM dominates initially but GVD soon catches up and leads to pulse contraction. This stage of temporal compression can be used for generating pulses with ultrashort durations [19–21]. However, the compressed pulses exhibit a low-amplitude structure outside the central lobe. An alternative technique that prevents sidelobe formation relies on the progressive evolution of the peak power and temporal duration of a fundamental soliton in a distributed amplifier or a dispersion decreasing (DD) fibre [22, 23]. Step-like or comb-like  dispersion profiled structures based on carefully chosen sets of fibres have been successfully used to emulate continuous DD fibre profiles.
The generation of high repetition rate pulse sources has largely benefited from the nonlinear compression effect taking place in the anomalous dispersion region, and several works have demonstrated the nonlinear reshaping of a sinusoidal beat-signal into well-separated pulses, the pulse repetition rate being simply determined by the frequency separation between the two continuous-wave (CW) laser sources. This technique has been successfully demonstrated with various experimental setups including DD fibres, adiabatic Raman compression in standard fibres, and step-like and comb-like dispersion profiled fibres. More recently, this nonlinear compression effect has been observed through a multiple four-wave mixing (FWM) process in a single anomalously dispersive fibre, and repetition rates ranging from a few tens gigahertz to 1 terahertz have been achieved . In the frequency domain, such nonlinear compression can be viewed as the result of a modulation instability  experienced by the initial beat signal during propagation in the fibre, with the generation of new sidebands via FWM: two pump photons at and interact to generate two first-order sideband photons at and , being the pump frequency detuning. High-order sidebands are then generated due to multiple FWM interactions. We note that a powerful alternative technique for realizing high-repetition-rate short-pulse sources relies on harmonic passive mode locking of fibre lasers [27–30]. The advantage of laser cavities as such compared to nonlinear pulse shaping in one-stage fibre systems is the possibility of achieving lower pulse train duty cycles. However, laser cavities have the drawbacks that they require mode locking, they cannot be referenced to an external clock directly and are not very suitable for the generation of pulses with ultrahigh repetition rates above a hundred gigahertz.
A typical experimental setup for the generation of high repetition rate pulse trains at telecommunication wavelengths is sketched in Figure 1(a). The initial beat signal is easily obtained via temporal superposition of two CWs with slightly different wavelengths delivered by external cavity lasers or a single CW directly modulated by an intensity modulator. A phase modulator driven at a frequency of a few hundreds of megahertz is used to avoid the deleterious effects of Brillouin back scattering. The beat signal is then amplified up to the Watt level by an erbium-doped fibre amplifier (EDFA) and propagated through a suitable optical fibre with anomalous dispersion to realize the nonlinear reshaping. According to the pulse source parameters that are chosen (pulse repetition rate, initial peak power, nonlinearity and dispersion coefficients of the compression fibre, and fibre length), various output pulse shapes can be obtained. Intensity and phase measurements based on the frequency resolved optical gating (FROG) technique  show that high-quality compressed pulses with a Gaussian intensity profile and nearly constant phase can be achieved at a typical duty cycle of 1/5 [25, 33] (Figure 1(b)). Lower duty cycles can still be obtained with a single fibre, but at the expenses of increased sidelobes in the wings of the pulses . Such sidelobes can be partly avoided by using specially designed arrangements of segments of fibres [35–37] or other comb-like structures.
We would like to note that the reshaping of a sinusoidal beat signal into ultrashort structures can be understood in terms of the nonlinear dynamics of “Akhmediev breathers’’ [38, 39]. In this context, the extreme spatiotemporal localization that can be observed (see, e.g., Figure 1(c)) is explained as a result of the formation of Peregrine solitons [31, 40], mathematical solutions of the standard NLS equation that have been first derived in 1983 in the hydrodynamics context  but have never been demonstrated experimentally before 2010, and using experiments in optical fibres. These observations offer a promising way to better understand the problem of the occurrence of rogue waves in optics and hydrodynamics [42, 43].
3.2. Generation of Parabolic Pulses in Active and Passive Fibres
Strong pulse reshaping can also occur in the normal regime of dispersion of a fibre. An important example that has generated a great deal of attention in the last decade is the occurrence of self-similar dynamical effects in the nonlinear propagation of ultrashort pulses in normally dispersive (ND) optical fibre amplifying media . Results have demonstrated a fundamentally new operating regime where the interaction of Kerr nonlinearity, dispersion, and optical gain is exploited to generate a particular class of pulses with a parabolic intensity profile and a strictly linear frequency chirp. These pulses then propagate in a self-similar manner, holding certain relations (scaling) between pulse power, duration, and chirp parameter. The results for the self-similar parabolic pulses are obtained by assuming that a fibre amplifier can be described by the NLS equation with gain where is the distributed gain coefficient. Using a self-similar ansatz and standard amplitude/phase decomposition, one can find self-similar parabolic pulse solutions in the quasiclassical limit of (2) , whose dynamic evolution is summarized as [45, 46] in the case of constant gain. Here, is the Heaviside function. The amplitude term indeed reveals a parabolic intensity profile, and the phase term a parabolic phase modulation or linear chirp with chirp rate . The peak amplitude and width of the pulse scale from their initial values, and the initial values depend only on the initial energy and amplifier parameters. These solutions possess the remarkable property of being a global attractor to the system for arbitrary initial conditions [47, 48]. By analogy with the well-known stable dynamics of solitary waves or solitons, these self-similar parabolic pulses have come to be known as “similaritons’’. In contrast to solitons, similaritons can tolerate strong nonlinearity without wave breaking. The normal GVD effectively linearizes the accumulated phase of the pulse allowing for the spectral bandwidth to increase without destabilizing the pulse . The unique properties of similariton pulses have motivated many theoretical and experimental studies (see, e.g., [46, 48, 50–53]).
Experimental demonstrations of similariton generation relying on amplification from either rare-earth doping (with ytterbium [45, 56–59] or erbium  dopants) or Raman scattering [50, 54, 60] have been achieved, confirming the potential of this method especially when dealing with the generation of high-power ultrashort pulses. Thanks to the high level of linearity of the chirp developed during parabolic amplification and as long as the impact of third-order fibre dispersion is moderate [52, 61, 62], it is possible to efficiently compensate for the chirp slope, so that compressed pulses with very low substructures and temporal durations much shorter than the initial seed pulse can be obtained [45, 51, 56–59]. As an illustration, Figures 2(a) and 2(b) show the setup and results of an experiment where similaritons are generated through Raman amplification at telecommunication wavelengths . Moreover, recent fibre lasers that use self-similar pulse shaping in the normal dispersion regime have been demonstrated to achieve high-energy pulses [63–66].
In addition to fibre amplifiers and lasers, stable similariton pulses can be generated in passive fibres provided a suitable longitudinal variation of the dispersion is introduced [55, 67–69] (Figure 2(c)). This approach is based on the observation that a longitudinal decrease of the normal dispersion is formally equivalent to linear gain. Recently, a simple approach to the generation of parabolic pulses that uses progressive nonlinear pulse reshaping in a ND fibre with fixed dispersion has been demonstrated . However, in contrast with the asymptotic similariton solutions obtained in fibre amplifiers, the generated parabolic waveforms represent transient states of the nonlinear pulse evolution in the passive fibre medium . As such, they have a finite life distance that depends sensibly on the initial conditions (pulse shape, energy, and chirp profile). Nevertheless, stabilization of the parabolic features is possible by use of a second propagation stage in a fibre with specially adjusted nonlinear and dispersive characteristics relative to the first fibre [70, 71].
3.3. Generation of Triangular Pulses
Parabolic shapes are not the only pulse waveforms that can be generated in a passive ND fibre. Recently, the combination of pulse prechirping and nonlinear propagation in a section of ND fibre has been introduced as a method for passive nonlinear pulse shaping, which provides a simple way of generating various advanced field distributions, including flat-top- and triangular-profiled pulses with a linear chirp . In this scheme, Kerr nonlinearity and GVD lead to various reshaping processes of an initial conventional pulse (e.g., a Gaussian pulse) according to the chirping value and power level at the entrance of the fibre. In particular, triangular pulses can be generated for a positive initial chirp parameter (using the definition for the phase profile) and sufficiently high energies.
These theoretical results have been confirmed experimentally by intensity and phase measurements of the generated pulses  (Figure 3(b)). In the experimental setup used (Figure 3(a)), the control of the pulse prechirping value was realized by propagation through different lengths of standard SM fibre with anomalous GVD, which imposed a positive chirp parameter on the pulse. The prechirped pulses were amplified to different power levels using an EDFA and then propagated through a ND fibre to realize the pulse reshaping.
Different nonlinear dynamics may lead to the generation of triangular pulses in a passive ND fibre. Indeed, it has been recently shown qualitatively and numerically that temporal triangular intensity profiles can result from the progressive reshaping of initially parabolic pulses driven by the fourth-order dispersion (FOD) of the fibre . The overall temporal effect of FOD on parabolic pulse propagation is to stretch and enhance the power reduction in the pulse wings, leading to a triangular profile. Furthermore, the possibility of triangular pulse shaping in mode-locked ring-cavity fibre lasers has been first reported in . It has been numerically demonstrated that for normal net dispersion, formation of two distinct steady-state solutions of stable single pulses can be obtained in a laser cavity in different regions of the system parameter space: the previously known similariton  and a triangular-profiled pulse with a linear frequency chirp.
3.4. Coherent Continuums for Optical Telecommunications
One of the most well-known examples of pulse reshaping in the spectral domain is in supercontinuum (SC) generation. SC generation in optical fibres, and more specifically, in photonic crystal fibres with enhanced nonlinearity, is an established technique for producing broadband light sources in a wide range of research fields including metrology, biophotonics, and optical telecommunications [74, 75]. In telecommunications, the broadened spectrum can be spectrally sliced to generate wavelength multiplexed pulse trains [76–78]. The principle of operation of a multiwavelength source is illustrated in Figure 4(a). An initial high-power mode-locked picosecond or femtosecond pulse train with a repetition rate of several gigahertz is spectrally broadened through SPM in a kilometer-long highly nonlinear (HNL) fibre. At the fibre output, the spectrum is sliced by adequate bandpass filters (BPFs) to obtain pulse trains that have the same repetition rate as the initial train but new central frequencies.
Typically the broadest spectra are generated in anomalously dispersive fibres, where the broadening mechanism is strongly influenced by soliton dynamics . However, solitonic effects and modulation instability lead to decreased temporal coherence and spectral flatness of the continuum generated in the anomalous dispersion regime . By contrast, the nonlinear pulse evolution in ND fibres leads to flatter spectra and improved temporal coherence, but at the expenses of relatively narrower spectra [82, 83]. Hence frequency broadening using a ND fibre is an attractive choice whenever a moderate amount of broadening alongside good spectral and temporal stability of the output pulses are targeted. However, the main limits to spectral pulse quality in the normal dispersion regime are the spectral ripple arising from SPM of conventional laser pulses, and the effects of optical wave breaking which may lead to significant change in the temporal pulse shape and severe energy transfer into the wings of the spectrum. These effects can in principle be avoided by using preshaped input pulses with a parabolic temporal intensity profile, which would preserve their shape whilst propagating within the fibre and, thus, result in spectrally flat, highly coherent pulses. Continuum with low-spectral ripple and high-energy density in the central part is indeed achievable through parabolic pulse propagation in ND-HNL fibre , and low-noise multiwavelength picosecond sources covering the whole C-band of optical telecommunications have been demonstrated based on this technique [12, 16, 79] (Figure 4(b)).
4. Applications of Parabolic and Triangular Pulses in Signal Processing
Applications of parabolic pulses have not been limited to ultrashort high-power pulse generation and highly coherent continuum sources, but several optical processing techniques have taken advantage of their specific features. These include optical regeneration [84, 85] including pulse retiming , prereceiver nonlinear processing in the optical domain [87, 88], and mitigation of linear waveform distortions [89, 90]. The simple intensity profile of triangular pulses is also highly desired for a range of processing applications, including time domain add-drop multiplexing [91, 92], wavelength conversion [93–95], optical signal doubling , time-to-frequency mapping of multiplexed signals , and enhanced spectral compression [98, 99]. In this Section, we will review some of these applications.
4.1. 2R Regeneration
As a first example, here we discuss the usage of parabolic pulses in 2R (reamplification, retiming) signal regeneration in an extension of the technique proposed by Mamyshev . The method relies on SPM in a nonlinear medium (fibre) and subsequent offset spectral filtering to suppress the noise in the zero-bit slots and the amplitude fluctuations in the one-bit pulses of return-to-zero (RZ) optical data streams. In the schematic of the Mamyshev regenerator depicted in Figure 5(a), the signal to be regenerated is first amplified to the optimum power level, and an optical BPF is also used to reduce the amplified spontaneous emission noise power. Then spectral broadening is achieved in a HNL fibre, and the broadened spectrum is partially sliced by a second BPF, which is shifted with respect to the input signal frequency in order to transmit SPM-generated frequencies and reject the original spectrum. The central frequency and output pulse shape of the regenerated signal are determined by the central frequency and spectral profile of the offset filter, respectively. The SPM phase shift experienced in the HNL fibre depends on the instantaneous power (cf. Section 2). Hence, a high-intensity pulse induces more SPM phase shift and spectrally broadens more than the low-intensity noise . Filtering the new SPM-generated frequencies with the offset filter leads to a power transfer function for the pulses and the noise which is close to a binary one .
Spectral filtering of similariton pulses can improve the ability of the Mamyshev regenerator to eliminate spurious noise pulses as well as to simultaneously reduce any fluctuations in the signal one-bit level . This ability relies on the specific features of self-similar amplification. Indeed, a spectrum broadened through self-similar amplification has a smooth profile (cf. Section 3.4), whereas a SPM-broadened spectrum is generally accompanied by oscillatory structures covering the entire frequency range. Moreover, the spectrum and chirp obtained by SPM both depend on the details of the initial pulse (shape, chirp, and energy), leading to some amplitude and time fluctuations of the regenerated pulses. In contrast, the similariton-based spectral broadening and similariton-induced chirp depend only on the initial pulse energy and/or amplifier parameters, respectively (cf. Section 3.2), so that both amplitude and timing jitter are reduced. In particular, the energy-dependent spectral broadening is responsible for efficient discrimination of high-energy pulses (ones) from low-energy pulses (zeros) with the offset BPF. An implementation of the similariton-based regeneration technique at 40 Gbit/s data rate where similariton pulses are generated through distributed Raman amplification in a ND fibre is illustrated in Figures 5(b) and 5(c). It is worth noting here that a distributed amplification is helpful in increasing the energy yield of the regenerator which is a highly dissipative element .
4.2. Linear-Distortion Compensation
As a second example of the application of parabolic pulses in signal processing, we review here the realization of a time-domain all-optical Fourier transformation (OFT) technique. Time-domain OFT in which the spectral profile is converted into a waveform in the time domain makes it possible to eliminate the waveform distortion caused by linear perturbations in optical fibres, such as higher order dispersion, jitter and polarization-mode dispersion [103–106]. Time-domain OFT is realized ideally by applying a quadratic temporal phase modulation (time lens) to a distorted pulse: and passing the linearly chirped pulse through a dispersive medium such as a short piece of fibre. When the accumulated dispersion of the medium equates the inverse of the chirp coefficient (i.e., when the chirp is fully compensated), the output waveform is proportional to the spectral amplitude before OFT: , where is the Fourier transform of , and the frequency is converted into time through the relationship . Since generally the spectral envelope profile has no distortion even if its time-domain waveform is distorted by linear perturbations, this frequency-to-time mapping indicates that a distortion-free pulse waveform can be obtained in the time domain after OFT. In [103–106], this compensation technique was investigated by using electrooptic phase modulators. But this way the quadratic modulation region was restricted to around the center of the sinusoidal modulation imparted by the phase modulator. Thus, any parts of the pulse extending beyond the quadratic region could not be properly transformed, and only the section of the target pulse sitting within the quadratic region could be compensated (Figure 6).
The use of XPM with parabolic pulses as a time lens has been recently proposed as a promising way to overcome the aforementioned limitation [89, 90]. Indeed, the chirp induced by XPM on the target pulse is proportional to the gradient of the intensity profile of the parabolic control pulse: , , so it is exactly linear and thus ideal OFT can be achieved by complete chirp compensation. Here, and are the respective peak amplitude and characteristic width of the parabolic pulse (cf. Section 3.2), and the sign is for either a standard “bright’’ or a dark parabolic pulse . The parabolic XPM-based OFT technique has been successfully experimentally demonstrated to achieve cancellation of the third-order dispersion-induced distortion of short-optical pulses [89, 90].
4.3. Optical Decision at the Receiver
In this section, we review a possible application of parabolic/flat-top pulses to the improvement of the signal bit-error rate (BER) in an optical communication system by using optical decision before the receiver. An attractive approach to the design of the optical receiver for high-speed fibre communication systems using RZ data formats is based on employing an additional all-optical decision element (ODE) just before the conventional receiver [87, 107–109]. In this way, the first decision is carried out in the optical domain, thus improving the quality of the received signal. The attractive possibility of improving the BER by using optical devices has been studied in some recent works [88, 110, 111]. The conceptual basis of the BER improvement by optical devices comes from the information theory: an intrinsic BER improvement is possible whenever the decision performed by the device in the optical domain is based on information that is different from the information used by the decision circuit of the (suboptimal) receiver in the electrical domain. In  an application of this general concept was demonstrated, based on using an advanced optical receiver enhanced by a nonlinear ODE. The example of an ODE scheme used in  exploits the nonlinear mechanism that leads to the formation of parabolic pulses and the resultant flattening of the signal waveform (cf. Section 3.2). The method is based on the nonlinear reshaping of a pulse towards a broad and flat temporal waveform that can occur upon propagation in a ND fibre  and subsequent slicing of the pulse temporal profile by an optical temporal gate (e.g., an amplitude modulator with a sharp nonlinear transfer function or a nonlinear optical loop mirror provided with a clock)  or XPM-based techniques.
The basic mechanism that is responsible for BER improvement in this scheme can be understood in the following way. The pulse temporal broadening and flattening in the ND fibre permits to recover the center of the bit slot for those pulses that are significantly shifted from the bit slot center in the input pulse train because of timing jitter (Figure 7(a)). Such strongly time-shifted pulses, once they are converted into electrical pulses and arrive at the decision point, might be missed by the threshold detector in those conventional receivers that use a relatively small fraction of the bit period. In contrast, the bit slot recovery in the ND fibre enables such pulses to be recognized as marks in the ODE-enhanced receiver. The slicing of the central portion of the broadened pulse temporal profile by the temporal gate enables efficient suppression of the timing jitter of the pulses which, in turn, improves the receiver sensitivity . This approach is illustrated in Figure 7(b), which shows that BER improvement over the conventional scheme, indeed, can be achieved using nonlinear signal processing in the optical domain before the conventional receiver. It is worth noting that the same processing technique based on temporal slicing of nonlinearly flattened pulse waveforms can also be used in all-optical 3R (2R + re-timing) signal regeneration .
4.4. Optical Signal Doubling and Frequency Conversion
Here we discuss the use of triangular pulses in the context of optical signal doubling and frequency conversion. A technique of copying optical pulses in both the frequency and time domains based on a combination of either XPM with a triangular pump pulse or SPM of a triangular pulse in a nonlinear Kerr medium and subsequent propagation in a dispersive medium was introduced in  and experimentally demonstrated in . In this scheme, spectral doubling of an optical signal is made possible by the XPM or SPM phase shift generated by a temporal intensity profile with a linear gradient: , ( and being the peak amplitude and characteristic width of a triangular pulse, resp.), which translates into a constant and distinct (opposite sign) frequency chirp induced onto the leading (downshifted) and trailing (upshifted) edges of the signal pulse. As a result of this constant and distinct chirp, under certain conditions the pulse spectrum develops a structure consisting of two equal peaks. The separation between the two spectral peaks increases with the maximum nonlinear phase shift , while their form is almost preserved. Under subsequent propagation of the modulated signal pulse in a linear dispersive medium, the produced spectral separation of the pulse components leads to their subsequent separation in time, thus allowing temporal replication of the pulse. In the case of normal dispersion, the pulse develops into a structure consisting of two identical pulses where the original pulse splits down the middle. The two pulse parts separate in time while experiencing dispersive broadening. The relative velocity of separation is proportional to the separation between the two peaks of the nonlinearly modulated pulse spectrum. Pulse splitting and separation occur also in the case of anomalous dispersion after an initial stage of pulse compression. Exact analytic expressions for the nonlinearly modulated pulse spectrum and the pulse temporal intensity distribution clearly show the features described above . Applying spectral filtering to the XPM/SPM modulated signal is also possible to realize efficient and clean frequency conversion [93–95].
Figure 8 shows results of the experiment reported in . Similarly to , triangular pulses were generated by passive nonlinear reshaping in a ND fibre. Spectral pulse doubling was realized through the SPM experienced by the triangular pulses over their life distance in a HNL fibre. The output SPM-shaped spectrum from the HNL fibre was sent into either a linear standard SM fibre segment to realize temporal pulse doubling or a wavelength demultiplexer filter for frequency conversion processing.
We have provided an overview of several recent examples of the use of nonlinear phenomena in optical fibres for the generation and shaping of optical pulses. We have discussed the generation of ultrashort pulse trains with very high-repetition rates in the anomalous dispersion regime of a fibre, the generation of parabolic-shaped pulses in active and passive ND fibres, the generation of pulses with triangular intensity profiles in passive ND fibres, and the generation of coherent continuums for optical telecommunications in ND fibres. Examples of new techniques or improvements in existing techniques of all-optical nonlinear fibre-based signal processing enabled by specialized pulse waveforms have been reviewed. Specifically, we have presented applications of parabolic pulses in optical signal regeneration, compensation of linear waveform distortions, and signal postprocessing in optical communication systems. Applications of triangular pulses in optical signal doubling and frequency conversion have also been discussed.
The authors would like to acknowledge and thank our colleagues, namely, Prof. Sergei K. Turitsyn, Dr. Paul Harper, Dr. Anton I. Latkin, Prof. Keith J. Blow, Dr. Julien Fatome, Dr. Kamal Hammani, Dr. Bertrand Kibler, Prof. Guy Millot, and Prof. John M. Dudley and the Optoelectronics Research Center (Southampton, UK). The authors also acknowledge support from the British Council (Alliance Grant 10.002), the Ministère des Affaires Étrangères et Européennes (Alliance Grant 22836ZJ), the Agence Nationale de la Recherche, and the Conseil Regional de Bourgogne (PARI Photcom).
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- Russian athletes cannot be allowed at Olympics, Zelensky says
- Ronaldo’s Al Nassr Knocked Out of Saudi Super Cup
- Al Nassr Coach Garcia Says “It’s a Positive Addition when You have a Player like Ronaldo”
- Hockey World Cup: New Zealand Beat India, Host India Lost Hope of Winning This World Cup
- Argentine Farmer Grows 124-Acre Image of Lionel Messi to Celebrate World Cup Triumph
News Barcelona player Arthur Melo reveals interesting conversation with Neymar Jr. regarding the Catalans
- Updated: July 20, 2018
FC Barcelona’s new recruit Arthur Melo has revealed an interesting anecdote involving him and his Brazilian counterpart Neymar Jr.
The midfielder has officially joined the Catalan club and reportedly said that Neymar had some kind words to say about his former club. Arthur reportedly remarked, “'When I was deciding whether to come or not, he sent me a message telling me about all the positive things at Barcelona.'
'He spoke about how it was a marvellous club, with very welcoming people, a great city. Lots of good things.'
Neymar certainly did not leave Barcelona in the best of circumstances. The winger’s release clause was triggered by PSG, and there was an undeniable breakdown in the relations between the player and the board.
His controversial move came at the back of a world-record transfer fee, but Barcelona were left with a huge hole to fill in the squad. However, the Catalans have addressed the issues and accordingly resolved him over the course of a year. Initially, Neymar’s transfer seemed to be a blatant shock, as the Brazilian was playing in one of the best clubs of the world.
His insistence on coming out of Lionel Messi’s shadow played a huge part in his move to Paris, but a foot injury had cut short his season in February itself.
Arthur was extensively courted by Barcelona, and the former Gremio man has finally put pen to paper on his deal. He appeared 50 times for the Brazilian club before his move to Spain.
It is understandable that Arthur consulted Neymar before finalizing a deal to join Barcelona. It is the first time that the midfielder would play outside of Brazil, and hence it is quite natural to assume that he discussed things related to Barcelona with Neymar.
The current-PSG man undoubtedly had issues with the board. However, the mere fact that he kept his differences aside whilst talking about his former club with Arthur is praiseworthy.

domain: sports


When mapping fluvial erosion hazard risk zones, it may be necessary to take additional steps to modify set-back distances according to the landforms and landscape features adjacent to the channel. LiDAR imagery and aerial photography may help in the identification and inclusion or exclusion of natural features within the risk zone. Two features of particular value are valley walls and meander scrolls.
Valley walls can be defined as the edge of the erodible valley bottom at which point the risk of fluvial erosion hazard becomes greatly reduced or even negligible. In Indiana, these may occur as abrupt changes in elevation, relative to the active channel and its floodplain, caused surficial exposure of material more resistant to erosion (i.e. bedrock) or ascension onto a terrace. Valley walls may contain fluvial erosion to within the lower valley bottom. As a result, valley walls may act as natural lines that may be followed to delineate risk of fluvial erosion hazard. Additionally, their inclusion within buffers created by mapping of set-back distance can be easily seen and appropriately adjusted. In the images immediately below, one can identify a number of instances where set-back lines have been mapped, but overlap areas of higher elevation, indicated by the areas of yellow to red shading in the LiDAR image, where the risk of fluvial erosion is less likely to exist (left). With this in mind, a preliminary fluvial erosion hazard map of this area, adjusted to account for the overlap with adjacent valley walls, may appear more like the area outlined with black borders (right).
This section is being updated – Please check back soon
Meander scrolls are former channel reaches that have since been severed and abandoned by the nearby active channel as it has migrated laterally. While currently not included in the active channel, meander scars are indicators of past channel positions. Comprised of alluvial sediments and often existing as depressions within the erodible corridor, meander scars can be particularly susceptible to reactivation by the active channel as it migrates laterally across the valley bottom. Unlike valley walls that require exclusion from preliminary set-back corridors, meander scars should be considered for inclusion into areas of concern. The Indiana FEH team is continuing to investigate the potential role of these and other landforms in fluvial erosion hazard mapping.


Make a Reservation The heart of rock & roll is still beating with the premier Huey Lewis tribute band, HIP TO BE SQUARE! Originally formed in
The heart of rock & roll is still beating with the premier Huey Lewis tribute band, HIP TO BE SQUARE!
Originally formed in 2013, this tight and fun band has played to thousands of cheering and dancing fans all over the U.S.
With a couple of fresh faces and an even better sound, HIP TO BE SQUARE is ready to Take You Back to the Future!
From their mega hits “Heart and Soul”, “Power of Love”, “Jacobs Ladder”, “Hip to be Square”, “I Want a New Drug”, and “If This Is It”, Huey Lewis & the News dominated the airwaves and MTV racking up an impressive list of 19 top ten hits throughout the 80’s.
In a concert experience that honors their legacy and includes “deep cut” hardcore fan favorites as well as their renowned acappella and doo-wop songs……..HTBS recreates all the sounds and energy of the original act. With blazing saxophone, gorgeous vocal harmonies, and incredible guitar hooks, their audiences are treated to an unforgettable evening reliving the memories and emotions linked to these classic songs!
(Thursday) 7:00 pm - 9:00 pm


International Carwash Show
Latest News | May 6, 2016
Join Giant Industries at the International Carwash Show May 9 through May 11 in Nashville, Tennessee. The ICA will be taking place at Music City Center. Giant Industries will be on hand to answer any questions you may have in booth 718. We hope to see you there! For more information on the show visit the show website here.
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The YMCA of Southern Arizona is accepting childcare applications from healthcare workers, first responders and other essential workers through May 22, the company announced.
The move, intended to help Tucson families meet their needs during the COVID-19 pandemic, opens up childcare opportunities at six total sites for children between 1 and 12.
“Before the current crisis, we offered a variety of services to our community, however, we immediately recognized the tremendous need for emergency child care as everyone’s daily lives changed instantly,” said YMCA President and CEO Kurtis Dawson, in a statement. “We currently serve more than 200 kids every day and are happy to be able to continue serving our community as the demands intensify. Our team is committed to providing a safe place for children where they can learn, grow, and thrive even during these challenging times.”
Financial assistance is available through the Arizona Department of Economic Security’s child care program and the Priority Care Assistance Program, and tiered pricing is available at the Y, beginning at $15 per day.
After May 22, the organization will switch to operating summer day camp programming. For more information visit tucsonymca.org
or email firstname.lastname@example.org

domain: news


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Because of the Dawes and Young Plan, which relieved war reparations, Germany after 1924 went through a small golden age. Consequently, the Expressionist Movement began to decline, eclipsed by the rising American film genre. Impressed by German techniques and films, American producers hired as many Expressionist filmmakers, designers, makeup artists and technicians they could get their hands on and the “character of German film dissolved into thin air like the vampire in Nosferatu”.  Few directors made critically acclaimed German films, especially German Expressionist films, from 1924-1932 because America had become the new center for artistic films. Some films like Pandora’s Box (1929), Diary of a Young Girl (1929), and M (1931) became critical successes but most German films ironically copied American films, which had integrated original techniques and styles from the early German Expressionist film era. Unfortunately, by 1927 the “German Artistic Cinema came to renounce the very qualities which gave it its value”. After 1927, Metropolis’s production bankrupted the UFA and the once proud studio was purchased by Alfred Hugenberg, a future supporter of the Nazi movement and Hitler. In 1932, Joseph Goebbels began to slowly take over all facets of the film industry bringing a new age of film during the Third Reich, the visions of the German Expressionist era transferred and lost to Americanization and the Nazi takeover. Goebbels banned films like Caligari from the German cinema, which contradicted the realistic, straightforward genre he and Hitler envisioned.
Though the German Expressionist era was short-lived, its pervasive influence on world cinema remains timeless. Caligari’s sets and dark themes influenced future filmmakers like Tim Burton, which culminated profoundly in The Nightmare Before Christmas’s (1993) sets and Edward’s design in Edward Scissorhands (1990).
(Scene from the Nightmare before Christmas)
Cesare from Caligari and Edward from Edward Scissorhands
Nosferatu greatly influenced the production of Dracula (1931), which sparked the American horror film genre, many of its scenes like The tied figure of the captain on the haunted ship copied from Murnau’s original film. Waxwork’s section on Harun al- Rashid influenced in its themes and conception Douglas Fairbank’s The Thief of Baghdad (1924). In addition, one of Waxwork’s actors William Dieterle later directed critically acclaimed American films like The Hunchback of Notre Dame (1923) and The Life of Emile Zola (1937).
As for Metropolis, it has become one of the most iconic films in world cinema and has influenced countless movies like The Bride of Frankenstein (1939), Blade Runner (1982), Dr. Stranglove (1964) and The Fifth Element (1997) and even Batman’s Gotham City.
Laboratory in The Bride of Frankenstein
Paul Leni described in an interview in 1924 his vision for Waxworks, which effectively embodied the universal goal his counterparts in the German studios throughout the 1920s:
For my film Waxworks I have tried to create sets so stylized that they evince no idea of reality. . . It is not extreme reality that the camera perceives, but the reality of the inner event, which is more profound, effective and moving than what we see through everyday eyes. . . I cannot stress too strongly how important it is for a designer to shun the world seen every day and to attain its true sinews. . . he must penetrate the surface of things and reach their heart. He must create mood (Stimmung) even though he has to safeguard his independence with regard to the object seen merely through everyday eyes. It is this which makes him an artist.
Above all, The German Expressionist film era represents a time in world cinema where people through the Filmwelt worked together to create wholly artistic films. Inevitably, these films reflected Germany’s torn state of mind, however in the process they brought films onto the level of a fine art and profoundly indefinitely changed the face of world cinema.
 Kracauer, From Caligari to Hitler, 134.
 Eisner, The haunted screen, 311.
 Leni, Paul No. 911, Kinematograph, 1924. Quoted in Eisner, The haunted screen, 127.

domain: artistic


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A: the time between death and donation is 12 to 36 hours for most organs and tissues surgery is scheduled as soon as possible after donation, the body is released to the funeral home. Religion and organ donation church to consider seriously the opportunity to donate organs after death that others may live, and that such decision be clearly. Home opinions health should organ donation be compulsory that everyone should donate their organs after death damage to your body after your death.
The deceased donation process only after brain death the surgical team removes the organs and tissues from the donor's body in an operating room first. Donation of body parts and organs after death should be compulsory organ donation should not be made compulsory no it shouldn't be organ donation should not be compulsory because people have such little control of what happens to them in their lives, they should be able to control what happens to their bodies after death. For organ donation after death, a medical assessment will be done to determine what organs can be donated certain conditions, such as having hiv , actively spreading cancer , or severe infection. Organ donation medical research projects without the assistance of human body donation after death, we would not have the medical advancements that we see today.
Organ donors: what happens to your body after death in organ donation absolutely nothing until you are truly dead and no longer need your body parts,. After death there is a limited window through which the organs are viable to be put on ice and then into the body of someone who needs them, and peoples lives are on the line and you are too dead to have a personhood to violate. Our mission is to spread awareness about organ donation in india once you register your wish on this website, you can download and print your donor card which will state your consent to having your organs and tissue made available for transplantation upon your death.
This essay will demonstrate the government should regulate the sale of all parts of the human body regarding organ donation and selling tissues, as well as the rules that are problematic, result in of many different opinions of each person. Since 2003, april has served as national donate life month and provided the health and transplant communities with an entire month of local, regional and national activities to help support and raise awareness around organ donation. Compulsory organ donation after death the hota is a mandatory organ donation scheme that applies to all singapore citizens and permanent residents aged 21 years old and above, regardless of religion hota may also apply to those below the age of 21, as long as the person's parent or guardian has consented to such removal.
A document used to specify the intent to donate organs or body parts after the donor's death forensic pathology the application of medical knowledge to questions of law. Organ and body donation: it should be encouraged, not made compulsory donating your organs for transplantation, or donating your body to medical science, is a very charitable act i myself do not believe that i will need my body or any of my body parts after i am dead (since i will not exist. Cartilage connective tissue that serves reconstruction of body parts such as the nose and a result of compulsory organ donationthey also argue that after death people they wish to donate. Mohan foundation is a not for profit organization that promotes organ donation and transplantation in india since 1997.
Why, before i am even cold, should the government (through legislation on compulsory organ donation) take ownership of my body i don't view it as anyone taking ownership of my body. It can be hard to think about what's going to happen to your body after you die, let alone donating your organs and tissue time of your death whether your organs. Three parts:deciding to donate your body to science discussing your decision filling out the paperwork to donate your body to science community q&a for some people, making a contribution to society doesn't stop with their death many choose to donate their organs, and some opt to donate their body.

domain: medical


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As research shows, stories written in a fun rhyming style are beneficial for kids and Skate Session is no exception. This book encapsulates an action-adventure story combined with captivating illustrations. The moral of wearing a helmet is addressed but most importantly, this book promotes the message ‘no matter how small one may be or one may feel, there is always one big adventure that can unfold close to home.
Another contemporary action-adventure story, Surf Safari brings surfing to young kids. When the humans go away, the creatures go out and play. However, like every surfers worst scenario & and the waves aren’t in motion! So do the creatures really surf? Or, do they just dream of surfing like the young audience after reading this book.
Shredding Snow is the latest in our series and a good sign that their is still plenty of adventures to be had. When the humans go away, the creatures will play and that exactly what the fun young creatures do. Offering authentic cutting-edge illustrations with a fun flowing story to be enjoyed by awesome parents and cool kids. This series has been influenced by muti-award winning children’s author and fan of ours; Lynley Dodd. And edited by past Children’s Book Council Australia’s mastermind Dr. Virginia Lowe, who once again gives her endorsement along with Olympic coach; Tom Willmott.
- Good wholesome entertainment, with a touch of RADical for kids. We aim to inspire children to DREAM BIG and live a healthy active lifestyle.
- Active Kids Books promote physical activity and literacy, helping curve the obesity crisis and get boys into reading.
- Created for rad kids, awesome parents and cool groovy grandparents.
- Active Kids Books’ first publication was first launched at The Byron Bay Writers Festival 2009.
- Active Kids Books have been endorsed by famous authors, professional athletes and CBCA judges.
- Distributed by Australia’s largest independent distributor and Dennis Jones and Associates.
Public, Private, Steiner, Community, Home Schooling inclusive.
- Choose from our awesome array of Activity Sheets and Units of Work designed for students Early Stage 1 and Stage 1. AKB resources are free, as we aim to inspire kids to DREAM BIG and live a healthy active lifestyle.
- Fan Mail: we love to receive kids written/ drawn etc. ‘fan’ mail…We try to respond to each fan that contacts us and post their awesomeness on our blog
- Have the Active Kids Books’ author or illustrator visit your School: Have your principle or deputy email us (see Contact page) with details of proposed dates, location, number of students etc. And we will reply with a quote.

domain: literature


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A very simple and relaxed piece, a juicy personalised recycled brass tag sits on a soft suede ribbon.
A perfect gift for both men and women this piece is so versatile and easy to wear. The recycled brass tag can be personalised with up to four characters and the lovely suede ribbon is long enough to tie easily as a necklace or will wrap around most wrists three times.
The brass tag charms are entirely handmade in rural Africa and each one is quite unique in its exact shape and finish, we consider that this is what makes our jewellery special. The recycled brass is from West Africa and comes from old plumbing fittings, collected and transformed using the ancient Asante Lost Wax Process. Each item is first hand molded in local honeybee wax giving evey piece it’s own particular identity. With no electricity available this is then fired in an earth kiln. The whole process gives the metal a wonderful worn quality.
For your personalised tag you can chose up to 5 characters including spaces and fullstops.
Please read the following carefully:
All letters are UPPERCASE and will be either 2mm, 3mm or 5mm depending on design. Please note the characters are stamped by hand, so alignment and spacing will not be precise but adds to the overall handmade nature of this item.
We are able to stamp letters, numbers, fullstops and ampersands, we also have a heart stamp as shown in the images. We DO NOT have other punctuation or symbols. All ‘+’ requested will be automatically replaced by ‘&’ and all ‘/’ will be replaced by ‘.’. Should you wish to have a heart stamped please use # to represent it.
Available in suede ribbon colours: black, natural, aubergine, turquoise.
100% recycled brass and suede
Wrap length approx 60cm
Tag approx 22mm x 8mm


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Thursday, July 19, 2012
I've only just discovered this this week. Brilliant idea.
Ad creatives James Beswick and Dan White remembered the late Beastie Boys rapper Adam "MCA" Yauch with a guerilla art installation at the MCA (Museum of Contemporary Art).
Their tribute, which is in aid of Cancer Council, involved hiring a professional human statue, decking him out in classic MCA gear and creating an unauthorised exhibit in one of the galleries. A placard resembling official signage was stealthily blu-taced to the wall beside the performer to help the illusion and explain the stunt to museum goers.


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If you could put comfort in a bowl, you’d end up with matzo ball soup. Chicken soup is legendary. This “Jewish penicillin” can conquer the common cold and, if you believe your Bubbe, can cure any hurt or illness. Add fluffy matzo balls and it’s the stuff family legends are made of.
When our family first went gluten-free, we mourned the lack of matzo ball soup. Chicken soup with rice just wouldn’t suffice. I tried to make gluten-free matzo balls from scratch, but instead of matzo balls we ended up with matzo lumps.
But when Passover rolled around, I found salvation. Salvation in a box.
Matzo balls contain, of course, matzo, which is made from wheat. However, some kosher for Passover brands of matzo ball mix are made from potato starch instead of matzo meal. That’s because some observant Jews don’t mix matzo with water during Passover, to prevent any possibility of it rising. Passover food that does not contain matzo is labeled non-gebrokts. (Gebrokts literally means “broken,” referring to matzo that is broken up and mixed with water.)
As Passover approaches, you can find several brands of gluten-free matzo meal. I buy four or five boxes to last well into the year. My favorite gluten-free matzo ball mixes are Paskesz Pesach Crumbs and Lieber’s Knaidel mix. (Paskesz’ gluten-free “Matzo Ball Mix” sounds like it would be great, but it produces knaidlach that are gummy instead of yummy.) Update: I’ve decided that Lieber’s Knaidel Mix makes the best gluten-free matzo balls. The recipe below follows the instructions for the Paskesz mix, so if using Lieber’s follow the directions on the box.
You’ll end up with perfectly round cream-colored balls that are fluffy on the outside, yet ever-so-slightly dense at the core (which, in my opinion, is a good thing). We’ve served them to gluten-eating friends who’ve asked for seconds and thirds.
To make the matzo balls, I use the recipe on the side of the box with just a few small changes. The recipe below uses Pesach Crumbs, because I can usually find those year-round in our kosher grocery store.
Some matzo ball tips: After you’ve made the matzo ball mixture, be sure to refrigerate it for at least 30 minutes. Then enlist your kids to help roll the mixture into walnut-sized balls. However, be gentle: The more you roll the balls, the denser they will be. Set aside all the balls onto a plate. When they all are rolled and ready, drop the balls into a pot of boiling water, so they all cook for the same amount of time. Use a large pot, so the matzo balls have room to fluff up and not crowd their neighbors.

domain: food


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In this timely Handbook, over 30 prominent academics, practitioners and regulators from across the globe provide in-depth insights into an area of law that the recent global financial crisis has placed in the spotlight: bank insolvency law.
Browse by title
Edited by Matthias Haentjens and Bob Wessels
This important book discusses the issue of executive compensation in Anglo-American financial markets following the financial crisis. The book begins by contextualizing the problem facing financial institutions in the US and the UK and argues that approaches to government and compensation reform are flawed. It then goes on to offer solutions and suggests that new reforms to executive compensation in financial institutions would be very welcome, despite certain limitations.
Comparing Models for Corporate Law, Securities Law and Competition Law
Regulatory competition within Europe and internationally, operates in several fields with different outcomes. This book offers a comparative legal and economic analysis of corporate, securities and competition law, exploring the reasons behind such differences.
The UNCITRAL Experience
This is a discerning analysis of international harmonisation efforts for secured credit law and examines the role of globalisation and finance capital in shaping such efforts. Gerard McCormack reveals how an ‘efficient’ law is often seen to increase the availability, and lower the cost, of credit, thereby contributing to international development. He considers whether the most comprehensive international standard – the United Nations Commission on International Trade Law (UNCITRAL) Legislative Guide (2008) – is actually suitable for adoption at the national level. In particular, he examines the hypothesis that American law and lawyers have shaped the content of the Guide to the extent that it is not suitable for translation into other laws.

domain: finance


Biden Is on a Roll That Any President Would Relish. Is It A Turning Level?
However this model salvages a few of the parts most essential to Democrats, and it’s nonetheless much more than Mr. Biden appeared more likely to get just some weeks in the past, when the seemingly limitless talks with Mr. Manchin appeared to break down as soon as and for all. When mixed with the $1.9 trillion Covid-19 aid plan handed simply weeks after Mr. Biden took workplace and the $1 trillion bipartisan infrastructure program accredited later that 12 months, the succession of spending plans add as much as probably the most expansive assertions of presidency within the fashionable age.
White Home officers famous the via strains within the numerous packages — the unique Covid aid plan included well being care spending, simply because the infrastructure plan included cash for local weather initiatives, each of that are then constructed upon within the newest bundle. Regardless of the political impression, the officers argued, the president had secured a major legacy.
And even amid Republican criticism, a few of the achievements have been bipartisan, a lot as Mr. Biden promised as a candidate. He’ll showcase two of them this week with back-to-back Rose Backyard ceremonies to signal the semiconductor measure on Tuesday and the burn pit invoice on Wednesday.
It’s an oddity of destiny that Mr. Biden’s most fruitful interval as president coincided along with his battle to shake covid, On the one hand, his compelled isolation saved him off the street and out of the general public eye, however he additionally had time for telephone calls with lawmakers after months of journey to Europe, Asia and the Center East that had taken him away from his home efforts.
From the White Home residence, in keeping with aides, Mr. Biden made a dozen calls to Democratic senators over the ultimate days earlier than passage of the climate-health bundle, typically reaching them within the cloakroom. His workers delivered White Home cookies to drained senators. Steven J. Richetti, Mr. Biden’s counselor, maintained an open channel to Mr. Manchin; Ron Klain, the White Home chief of workers, saved in contact with Senator Chuck Schumer of New York, the Democratic chief, as soon as a day and typically extra typically.
Mr. Ricchetti and Louisa Terrell, the White Home director of legislative affairs, stayed all evening on the White Home over the weekend to watch the marathon voting within the Senate and preserve Mr. Biden updated.


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Item: US Metal Halloween Tin Horn US Metal
This item is from the 1950's and comes with a yellow plastic mouth piece. Great and colorful with spider webs,flying witch and bats. Marked. Has orange base and yellow and orange stripes inside of the base. 8979-41RP
Item Condition: NM
DIMENSIONS: 12" tall by 2.75" wide
Stock #: 8979f
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Dear Parents / Guardians,
Averill Park Central School District buildings will remain closed through April 28 per Governor Cuomo’s new Executive Order to stop the spread of the COVID-19 pandemic. Under this order, our school district must continue to provide online learning, meals for students and childcare for essential workers every weekday through April 28.
The state will reassess whether to extend the statewide school closures past this date. We encourage families to continue to check their email and our website for additional information.


We made our views clear after a freedom of information release to The Herald revealed that first minister Humza Yousaf had invited Turkish President Recep Erdoğan on a diplomatic visit to Scotland. Turkey’s human rights record and previously well-regarded commitment to secularism have both plummeted under Erdoğan’s authoritarian rule.
Responding to news about the invitation, which was offered at Cop28 in December, our CEO Fraser Sutherland stated:
“This is a very short sighted invite from the first minister. Under President Erdoğan Turkey has seen a sustained attack on civil liberties and human rights. Allegations of torture against political prisoners are widespread and the Turkish government censors and blocks webpages of news websites that are critical of the governing party.
“The country installed a blasphemy law this century through its reform of penal codes. In 2015 the Turkish Atheist Association had its website banned by a court for ‘disrupting public order.’ The United States Commission on Religious Freedom states that ‘the Turkish government’s use of this article [blasphemy] is generally politically motivated.’
“Erdogan is an authoritarian despot. He should not be welcomed to Bute House by this first minister or any who follow him.”
Image c. Paul Morigi/Creative Commons.
Latest Related Stories
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We tell UN human rights committee that compulsory religious observance in Scottish schools must end
February 14, 2024
We comment on Humza Yousaf’s relationship with evangelical businessman Brian Souter, funder of US-based organisations alleged to have covered up sexual assault in US
February 12, 2024
Humanist Society interview series: Alice Murray of Back Off Scotland on abortion clinic harassment
February 11, 2024


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The Great K & A Train Robbery was filmed in Glenwood Canyon in 1926. Tom Mix, the star, did his own stunts, including some on a moving train, that thrilled those watching. James J. Flynn was the fireman on the train in the film. He had a picture of Tom Mix with the train crew which he submitted to the Green Light, a magazine for Denver and Rio Grande Western Railroad employees. The magazine no longer exists but this clipping of the article was...


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4/10/2013 10:30:00 PM
Courtesy of 6one7 Productions:
Enter to win a pair of Justin Timberlake & Jay-Z "On the Field" tickets at Fenway Park!!!
This RSVP is considered (1) entry into our Justin Timberlake & JAY-Z "On the Field" ticket giveaway. One luck winner willl win a pair of "On the Field" tickets to see the duo perform at Fenway Park on Saturday August 10th. Limited to one entry per person, per email, per day. Winner will be chosen by a random drawing of names submitted by Thurs. August 9th 2013.
Click (here) to enter.
Know of Any Interesting Boston News or Events That You'd Like to Share?
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domain: entertainment


Make easy monthly payments. Select Affirm at checkout.Learn more
This is a used Yamaha NCX700, a classical nylon string guitar with a thinline body and comfortable neck profile that make this a fantastic choice for electric or steel-string players looking to dip their toes into nylon-string instruments in a comfortable and familiar way. The guitar is used, there is a crack near the tail block and one coming off of the bass side bride wing. It's being sold as is!
- Natural Finish
- Solid Sitka Spruce Top
- Eastern Mahogany Back and Sides
- African Mahogany Neck
- Ebony Fretboard
- 25.59" Scale Length
- 2" Nut Width
- Yamaha System 61 A.R.T. 2-Way System Electronics
- Rosewood Bridge
Since 1994 The Music Zoo has been a trusted source for musicians around the world. We've located guitars for Slash, sold guitars for Steve Miller, held performances by major artists like Steve Vai, built thousands of customer relationships, and helped countless enthusiasts find just the right instrument. Today we look forward to finding your next guitar!


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SEATTLE — December 5, 2022 — Women were underrepresented in COVID-19 treatment clinical trials, and some racial and ethnic groups were underrepresented in COVID-19 prevention trials, according to a new meta-analysis conducted by Fred Hutchinson Cancer Center in collaboration with researchers from Beijing and London.
The study, published in JAMA Internal Medicine, identified system-wide differences in representation among several key demographic groups in COVID-19 prevention and treatment trials in the U.S.
“To our knowledge, this is the first study to comprehensively examine demographic representation across the landscape of both COVID-19 prevention and treatment trials over the first two years of this pandemic,” said Hong Xiao, PhD, researcher in the Public Health Sciences Division at Fred Hutch and the lead author for the study.
By the numbers
Overall, the meta-analysis examined 122 U.S.-based clinical trials for COVID-19 vaccines or treatments, involving more than 175,000 participants. The selected trials were those registered on ClinicalTrials.gov or published in PubMed from October 2019 to February 2022. Only studies that provided data about enrolled participants by sex, race or ethnicity were analyzed in this study. Representation rates from trials were compared to expected rates in the U.S. COVID-19 population.
Key findings from their review included:
The study authors noted that female participants historically have been underrepresented in clinical trials in general for various reasons. Pregnant women have routinely been excluded from clinical trials; as such, women of reproductive age may have had greater concerns about how developmental COVID-19 treatments would affect their health and current or future fertility.
The authors also speculated that Hispanic overrepresentation might have occurred for several reasons, including the fact that one-third of the U.S.-based COVID-19 trial sites were in California, Texas and Florida – areas with large Hispanic populations. Additionally, COVID-19 treatment trials were typically conducted among inpatient populations, which may have disproportionately affected Hispanic populations due to a lack of primary care and increased risk for COVID-associated hospitalizations.
“In many instances, our findings highlight achievements in the successful enrollment of historically underrepresented patients. However, our findings also underscore that despite efforts to eliminate sex, racial and ethnic disparities, gaps in reporting and differences in representation in U.S.-based COVID-19 trials have persisted,” said Joseph M. Unger, PhD, MS, Fred Hutch biostatistician and health services researcher and the study’s senior author. “Clearly, more progress needs to occur to fully close these gaps and achieve greater diversity among participants.”
“This vital work by Fred Hutch researchers and their collaborators highlights the ongoing disparities in who accesses and enrolls in clinical research,” added Rachel Bender Ignacio, MD, medical director of the COVID-19 Clinical Research Center at Fred Hutch. “We must remain laser-focused on ensuring that clinical-trial participation is representative of the general population, which both requires trust in and access to research, and also ensures that the products of that research are acceptable to and appropriate for everyone.”
Xiao, Unger and the rest of the study authors concluded that additional strategies are needed to ensure that all trial sponsors, whether federally supported or industry-funded, are held accountable for appropriate representation of females and racial and ethnic groups in clinical trials.
Research reported in this publication was supported by the Public Health Sciences Division at Fred Hutchinson Cancer Center. The sponsor had no other involvement beyond financial support.
Potential conflicts of interest
The authors declare no competing interests related to the study.
About Fred Hutch
Fred Hutchinson Cancer Center unites comprehensive care and advanced research to provide the latest cancer treatment options and accelerate discoveries that prevent, treat and defeat cancer and infectious diseases worldwide.
Based in Seattle, Fred Hutch is an independent, nonprofit organization and the only National Cancer Institute-designated cancer center in Washington. We have earned a global reputation for our track record of discoveries in cancer, infectious disease and basic research, including important advances in bone marrow transplantation, HIV/AIDS prevention, immunotherapy and COVID-19 vaccines. Fred Hutch operates eight clinical care sites that provide medical oncology, infusion, radiation, proton therapy and related services and has network affiliations with hospitals in four states. Fred Hutch also serves as UW Medicine’s cancer program.
Please note that our organization was renamed Fred Hutchinson Cancer Center in April 2022, following the merger of long-time partners, Fred Hutchinson Cancer Research Center and Seattle Cancer Care Alliance.

domain: health