Spectrum

1] A comparison of radiative transfer models for simulating radiances from the Atmospheric Infrared Sounder (AIRS), has been undertaken. Results from 14 line-by-line and fast parameterized infrared models were submitted. Several aspects of the models were compared. First, the forward model calculations for all 2378 AIRS channels for 52 diverse atmospheric profiles and one tropical Pacific profile coincident with AIRS data were performed for three local zenith viewing angles: nadir, 45, and 60 degrees. Second, for a subset of the models and only 20 AIRS channels the transmittances from each layer to space were provided. Finally, for some models the Jacobians with respect to temperature, water vapor, and ozone were also computed. For the forward model calculations, most models agree to within 0.02 K when compared to a reference lineby-line model averaged over a subset of profiles, with the exception of a few spectral regions. When compared with AIRS observations, however, the mean differences increase to 0.2 K, and for a few models even greater differences are seen. The transmittance differences highlighted regions of the spectrum where the spectroscopy of the models differs, particularly in the carbon dioxide absorption bands at 667 cm À1 and 2386 cm À1 . For the Jacobians all models have some profiles/channels that do not fit the reference well, and the main problems are documented here. The model differences only increase slightly for off-nadir viewing angles for both forward and Jacobian calculations.

Mitochondrial DNA depletion syndromes (MDSs) form a group of autosomal recessive disorders characterized by profoundly decreased mitochondrial DNA copy numbers in affected tissues. Three main clinical presentations are known: myopathic, encephalomyopathic and hepatocerebral. The first is associated with mutations in thymidine kinase 2 (TK2) and p53-induced ribonucleotide reductase B subunit (RRM2B); the second with mutations in succinate synthase A (SUCLA2) and B (SUCLG1); the third with mutations in Twinkle (PEO1), pol-γA (POLG1), deoxyguanosine kinase (DGUOK) and MPV17 (MPV17). In this work, we review the MDS-associated phenotypes and present our own experience of 32 MDS patients, with the aim of defining the mutation frequency of the known genes, the clinical spectrum of the diseases, and the genotype–phenotype correlations. Five of our patients carried previously unreported mutations in one of the eight MDS genes.

The open string ending on a D-brane with a constant B-field in a pp-wave Ramond-Ramond background is exactly solvable. The theory is controlled by three dimensionful parameters: α ′ , the mass parameter (RR background times the lightcone momentum) and the B-field. We quantize the open string theory and determine the full noncommutative structure. In particular, we find a fully noncommutative phase space whose noncommutativity depends on all these parameters. The lightcone Hamiltionian is obtained, and as a consequence of the nontrivial commutation relations of the theory, new features of the spectrum are noted. Various scaling limits of the string results are considered. Physical implications are discussed.

Frequency modulation (FM) spectroscopy is a new method of optical heterodyne spectroscopy capable of sensitive and rapid measurement of the absorption or dispersion associated with narrow spectral features. The absorption or dispersion is measured by detecting the heterodyne beat signal that occurs when the FM optical spectrum of the probe wave is distorted by the spectral feature of interest. A short historical perspective and survey of the FM spectroscopy work performed to date is presented. Expressions describing the nature of the beat signal are derived. Theoretical lineshapes for a variety of experimental conditions are given. A signal-to-noise analysis is carried out to determine the ultimate sensitivity limits.

Thunderstorms and the lightning that they produce are inherently interesting phenomena that have intrigued scientists and mankind in general for many years. The study of thunderstorms has rapidly advanced during the past century and many efforts have been made towards understanding lightning, thunderstorms and their consequences. Recent observations of optical phenomena above an active lightning discharge along with the availability of modern technology both for data collection and data analysis have renewed interest in the field of thunderstorms and their consequences in the biosphere. In this paper, we review the electrification processes of a thunderstorm, lightning processes and their association with global electric circuit and climate. The upward lightning discharge can cause sprites, elves, jets, etc. which are together called transient luminous events.

This is a literature review about large granular lymphocyte leukemia (LGLL), a rare and misdiagnosed oncohematological disease, characterized by a clonal expansion of T-cells (T-LGLL) or NK-cells (NK-LGLL) in the bone marrow and/or peripheral blood. The clinical features of LGLL include cytopenias (anemia, neutropenia and thrombocytopenia), lymphocytosis (usually discrete), lymphadenopathy, hepatomegaly, splenomegaly, immune abnormalities and constitutional symptoms (fever, night sweats and weight loss). The diagnosis is based on the confirmation of the clonality of T-cells or NK-cells (polymerase chain reaction and Southern blot are the two methods most commonly used) and typical findings of the immunophenotypic analysis of peripheral blood lymphocytes (flow cytometry analyses for specific surface antigens). In contrast to the chronic and indolent course of T-LGLL, NK-LGLL has an acute presentation and poor clinical outcome. There are different current treatment options, depending on clinical presentation.

The present paper describes a pilot and follow-up study of the preliminary development of a new tool to screen for Asperger Syndrome (AS) and related social and communication conditions (the CAST: Childhood Asperger Syndrome Test) in children aged 4-11 years, in a non-clinical setting. Pilot Study: Parents of 13 children with AS and 37 typically developing children completed the CAST. There were significant differences in mean scores, with the AS sample mean of 21.08 (range 15 -31) and the typical sample mean of 4.73 (range 0 -13). The Pilot was used to establish preliminary cut-off scores for the CAST. Main Study: Parents of 1150 primary-school-age children were sent the CAST, with 199 responders and 174 taking part in the full data analysis. Results suggest that compared to other tools currently available, the CAST may be useful for identifying children at risk for AS and related conditions, in a mainstream non-clinical sample.

In this study, we demonstrate the versatility of matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOFMS) protein profiling for the species differentiation of a diverse suite of Bacillus spores. MALDI-TOFMS protein profiles of 11 different strains of Bacillus spores, encompassing nine different species, were evaluated. Bacillus species selected for MALDI-TOFMS analysis represented the sporeforming bacterial diversity of typical class 100K clean room spacecraft assembly facilities. A one-step sample treatment and MALDI-TOFMS preparation were used to minimize the sample preparation time. A library of MALDI-TOFMS spectra was created from these nine Bacillus species, the most diverse protein profiling study of the genus reported to date. Linear correlation analysis was used to successfully differentiate the MALDI-TOFMS protein profiles from all strains evaluated in this study. The MALDI-TOFMS protein profiles were compared with 16S rDNA sequences for their bacterial systematics and molecular phylogenetic affiliations. The MALDI-TOFMS profiles were found to be complementary to the 16S rDNA analysis. Proteomic studies of Bacillus subtilis 168 were pursued to identify proteins represented by the biomarker peaks in the MALDI-TOFMS spectrum. Four small, acid-soluble proteins (A, B, C, and D), one DNA binding protein, hypothetical protein ymf J, and four proteins associated with the spore coat and spore coat formation (coat JB, coat F, coat T, and spoIVA) were identified. The ability to visualize higher-molecular-mass coat proteins (10 to 25 kDa) as well as smaller proteins (<10 kDa) with MALDI-TOFMS profiling is critical for the complete and effective species differentiation of the Bacillus genus.

The SystemVerilog 3.1 language initiative includes the requirement to bring together design, testbench, and assertion-based descriptions into a consistent, backward compatible, evolutionary language standard that achieves determinism and common semantics across the spectrum of design and verification tools. This paper describes the algorithm proposed for the new scheduling semantics that meets these demanding requirements. This algorithm achieves predictable and consistent results across design and verification tools. This proposal has been donated to the Accellera SystemVerilog 3.1 standardization technical committees. Standardization of this new algorithm will extend these benefits to users of other tools.

Autism Diagnostic Observation Schedule (ADOS) Modules 1-3 item and domain total distributions were reviewed for 1,630 assessments of children aged 14 months to 16 years with an autism spectrum disorder (ASD) or with heterogeneous nonspectrum disorders. Children were divided by language level and age to yield more homogeneous cells. Items were chosen that best differentiated between diagnoses and were arranged into domains on the basis of multifactor item-response analysis. Reflecting recent research, the revised algorithm now consists of two new domains, Social Affect and Restricted, Repetitive Behaviors (RRB), combined to one score to which thresholds are applied, resulting in generally improved predictive value.

Hydrometeors spectra evolution induced by coalescence processes is simulated using a microphysical model of the Berry and Reinhard (1974) type including hydrometeors of seven kinds: water drops, plate-like and columnar crystals, dendrites, snowflakes, graupel and hail. The sensitivity of spectra evolution to several parameters, such as air temperature, drop freezing rate, initial liquid water and ice particles content is studied. The Berry and Reinhard (1974) method was used for numerical integration of corresponding stochastic coalescence equations. A remarkable impact of ice processes on the evolution of hydrometeors of all types is demonstrated. The amount of large droplets in mixed phase experiments is significantly less than that in the experiment without the ice phase. The main factor causing the cessation of water spectrum broadening is connected with a crucial decrease of the coalescence rate between water droplets due to permanent elimination of the largest droplets from the drop spectrum as a result of ice-water interaction and drop freezing. The results of simulations show that when only coalescence processes are considered, relative amounts of snowflakes and graupel crucially depend on air temperature. Under comparably high temperatures it is snowflakes that are the dominating hydrometeor type, while under low temperatures graupel can be the dominating hydrometeor type due to an increased rate of drop freezing. A high sensitivity of snowflake/graupel content ratio to the initial size of crystals is demonstrated. Initial liquid water content in model experiments appears to be one of the most important factors determining the formation not only of graupel, but of snowflakes as well. Results indicate the existence of a "critical" minimum concentration of water drops and minimum broadness of the drop size spectrum, which means that when the corresponding values are smaller there is no large snowflake or graupel generation.

This study examined whether language deficits persist even in children with optimal outcomes. We examined a group of children with prior diagnoses on the autism spectrum who had IQs in the normal range, were in age-appropriate mainstream classes, and had improved to such an extent that they were considered to be functioning at the level of their typically developing peers. Fourteen such children between the ages of five and nine were matched on age and sex with typically developing children, and were given a battery of 10 language tests to investigate their language abilities. Results indicated that while these children's grammatical capabilities are mostly indistinguishable from their peers, they are still experiencing difficulties in pragmatic and semantic language.

ÐEfficient and effective buffering of disk blocks in main memory is critical for better file system performance due to a wide speed gap between main memory and hard disks. In such a buffering system, one of the most important design decisions is the block replacement policy that determines which disk block to replace when the buffer is full. In this paper, we show that there exists a spectrum of block replacement policies that subsumes the two seemingly unrelated and independent Least Recently Used (LRU) and Least Frequently Used (LFU) policies. The spectrum is called the LRFU (Least Recently/Frequently Used) policy and is formed by how much more weight we give to the recent history than to the older history. We also show that there is a spectrum of implementations of the LRFU that again subsumes the LRU and LFU implementations. This spectrum is again dictated by how much weight is given to recent and older histories and the time complexity of the implementations lies between O(1) (the time complexity of LRU) and ylog P n (the time complexity of LFU), where n is the number of blocks in the buffer. Experimental results from trace-driven simulations show that the performance of the LRFU is at least competitive with that of previously known policies for the workloads we considered.

Single crystals of L-Tartaric acid (C 4 H 6 O 6), an organic nonlinear optical (NLO) material, have been grown by hanging seed solution and submerged seed solution techniques at room temperature. The crystal system has been confirmed from the single crystal X-ray diffraction analysis. The crystalline perfection was evaluated using high-resolution X-ray diffractometry (HRXRD). From this analysis, it was found that the quality of the crystal is quite good. The functional groups were identified using FTIR spectroscopy. UV-vis-NIR spectrum showed the absence of absorption in the wavelength region of 220-900 nm. The second harmonic generation efficiency is 89% compared to that of standard potassium dihydrogen phosphate (KDP). The laser damage threshold value is much higher than that of KDP and closer to that of b-barium borate.

F. Granelli et al. (Eds.): MOBILIGHT 2009, LNICST 13, pp. 230–241, 2009. © ICST Institute for Computer Sciences, Social-Informatics and Telecommunication Engineering 2009 ... Self-management in Future Internet Wireless Networks: ... Dynamic Resource Allocation and Traffic Routing ...

Strain-dependent hydraulic conductivities are uniquely de®ned by an environmental factor, representing applied normal and shear strains, combined with intrinsic material parameters representing mass and component deformation moduli, initial conductivities, and mass structure. The components representing mass moduli and structure are de®ned in terms of RQD (rock quality designation) and RMR (rock mass rating) to represent the response of a whole spectrum of rock masses, varying from highly fractured (crushed) rock to intact rock. These two empirical parameters determine the hydraulic response of a fractured medium to the induced-deformations. The constitutive relations are veri®ed against available published data and applied to study one-dimensional, strain-dependent¯uid¯ow. Analytical results indicate that both normal and shear strains exert a signi®cant in¯uence on the processes of uid¯ow and that the magnitude of this in¯uence is regulated by the values of RQD and RMR.

This invited paper presents a number of correlated specifications of example railway system problems. They use a variety of partially or fully integrated formal specification. The paper thus represents a mere repository of what we consider interesting case studies. The existence of the Unified Modeling Language [10, 67, 36, 20] has caused, for one reason or another, the research community to try formalise one or another facet of UML. In this paper we report on another way to achieve what UML attempts to achieve: Broadness of application, convenience of notation, and multiplicity of views. Whether these different UML views are unified, integrated, correlated or merely co-located is for others to dispute. We also seek to support multiple views, but are also in no doubt that there must be sound, well defined relations between such views. We thus report on ways and means of integrating formal techniques such as RAISE (RSL) [58, 59],

Critical Infrastructures, such as energy, banking, and transport, are an essential pillar to the well-being of the national and international economy, security and quality of life. These infrastructures are dependent on a spectrum of highly interconnected information infrastructures for their smooth, reliable and continuous operation. The field of protecting such Critical Information Infrastructures, or CIIP, faces numerous challenges, such as managing the secure interaction between peers, assuring the resilience and robustness of ...

The difficulties that a neural network faces when trying to learn from a quasiperiodic time series are studied analytically using a teacher-student scenario where the random input is divided into two macroscopic regions with different variances, 1 and 1/γ 2 (γ 1). The generalization error is found to decrease as g ∝ exp(−α/γ 2), where α is the number of examples per input dimension. In contradiction to this very slow vanishing generalization error, the next output prediction is found to be almost free of mistakes. This picture is consistent with learning quasi-periodic time series produced by feedforward neural networks, which is dominated by enhanced components of the Fourier spectrum of the input. Simulation results are in good agreement with the analytical results.

We consider a model with global Abelian chiral symmetry of two massless fermion fields interacting with a complex massive scalar field. We argue that the Schwinger-Dyson equations for the fermion and boson propagators admit ultraviolet-finite chiral-symmetry-breaking solutions provided the Yukawa couplings are large enough. The fermions acquire masses and the elementary excitations of the complex scalar field are the two real spin-zero particles with different masses. As a necessary consequence of the dynamical chiral symmetry breakdown both in the fermion and scalar sectors, one massless pseudoscalar Nambu-Goldstone boson appears in the spectrum as a collective excitation of both the fermion and the boson fields. Its effective couplings to the fermion and boson fields are calculable.

This paper traces the history of physics education in America from the time of the revolution to the present. Various reform efforts, innovations, and movements fostering educational change are described. The evolution of high school physics from its inception in this country from no laboratory work for students to laboratory work and from simple laboratory work to a more sophisticated experience in the laboratory is outlined. The evolution of coursework and texts are also discussed. Contains 24 references.

We report on high-resolution spatial and timing results for binary millisecond pulsar PSR J0218+4232 obtained with the Chandra HRC-I and HRC-S in imaging mode. The sub-arcsecond resolution image of the HRC-I (0.08-10 keV) showed that the X-ray emission from PSR J0218+4232 is consistent with that of a point source excluding the presence of a compact nebula with a size of about 14 ′′ for which we had indications in ROSAT HRI data. The presence of a DC component is confirmed. This X-ray DC component has a softer spectrum than the pulsed emission and can be explained by emission from a heated polar cap. With our HRC-S observation we obtained a 0.08-10 keV pulse profile with high statistics showing the well-known double peaked morphology in more detail than before: The two pulses have broad wings and pulsed emission appears only to be absent in a narrow phase window of width ∼ < 0.1. The absolute timing accuracy of ∼ 200µs makes it possible to compare for the first time in absolute phase the X-ray pulse profile with the highly structured radio profile and the high-energy γ-ray profile (0.1-1 GeV). The two X-ray pulses are aligned within absolute timing uncertainties with two of the three radio pulses. Furthermore, the two γ-ray pulses are aligned with the two non-thermal X-ray pulses, corresponding to a probability for a random occurrence of 4.9σ, strengthening the credibility of the earlier reported first detection of pulsed high-energy γ-ray emission from a (this) millisecond pulsar.

We investigate symbolic sequences and in particular information carriers as e.g. books and DNA–strings. First the higher order Shannon entropies are calculated, a characteristic root law is detected. Then the algorithmic entropy is estimated by using Lempel–Ziv compression algorithms. In the third section the correlation function for distant letters, the low frequency Fourier spectrum and the characteristic scaling exponents are calculated. We show that all these measures are able to detect long–range correlations. However, as demonstrated by shuffling experiments, different measures operate on different length scales. The longest correlations found in our analysis comprise a few hundreds or thousands of letters and may be understood as long–wave fluctuations of the composition. 1

Data from paleomagnetic and sedimentological studies carried out on four cores from the bottom sediments of Lake Moreno (southern Argentina) were integrated with data obtained by Creer et al., Geophys. J. R. Astron. Soc., 74 (1983), 109. Within-lake correlations are based on the magnetic susceptibility and intensity of remanent magnetization. The individual measurements were stacked and transformed to a time-scale

Cognitive radio has the ability to sense the environment and adapt its behavior to optimize communication features, such as quality of service in the presence of interference and noise. In physical layer to achieve this goal, different phases of sensing, channel estimation, and configuration selection are necessary. The sensing part measures the interference level, recognize the spectrum holes, and send this information to channel estimator. In the next step, channel state information (CSI) is used for data detection and also sent to the transmitter through a limited feedback. CSI feedback consists of achievable rate, SNR value, modulation or coding schemes (MCS). Feedback link improves the system performance in the cost of complexity and delay. In this paper, we present and compare different feedback schemes for cognitive radio and study the channel capacity when an imperfect feedback link is corrupted by noise and delay.

A new paradigm for active galactic jet kinematics has emerged through detailed investigations of BL Lac objects using very long baseline radio interferometry. In this new scheme, most, if not all, jet components appear to remain stationary with respect to the core but show significant non-radial motions. This paper presents results from our kinematic investigation of the jets of a statistically complete sample of radio-loud flat-spectrum active galaxies, focusing on the comparison between the jet kinematic properties of BL Lacs and flat-spectrum radio-quasars. It is shown that there is a statistically significant difference between the kinematics of the two AGN classes, with BL Lacs showing more bent jets, that are wider and show slower movement along the jet axis, compared to flat-spectrum radio-quasars. This is interpreted as evidence for helically structured jets.

Publish-subscribe middleware allows the components of a distributed application to subscribe for event notifications and provides the infrastructure enabling event routing from sources to subscribers. This model decouples publishers from subscribers, and in principle makes it amenable to highly dynamic environments. Nevertheless, publish-subscribe systems exploiting a distributed event dispatcher are typically not able to rearrange dynamically their operations to adapt to changes impacting the topology of the dispatching infrastructure. In this work, we first describe two solutions available in the literature that constitute the extremes of the reconfiguration spectrum in terms of the number of nodes potentially affected by the reconfiguration. They differ essentially in the tradeoffs between simplicity and efficiency. Then, we introduce our contribution as a new algorithm that strikes a balance between the aforementioned solutions by tolerating frequent reconfigurations at the cost of moderate overhead.

The results of investigation of the spectral characteristics of radiation in the presence of the photonic flame effect recently discovered experimentally are presented. Radiation from a ruby laser operating in the Q-factor modulation regime with a generation wavelength of 694.3 nm is focused near the oriented surface of a globular photon crystal (artificial opal with a globule size of 230 nm) placed on a copper cold guide whose temperature is close to the liquid-nitrogen boiling point (77 K). The spectrum of long-term afterglow (with a duration of about several seconds when the duration of a pump pulse is equal to 20 ns) appearing in the photonic flame effect is detected using a fiber optic minispectrometer and consists of several comparatively narrow lines whose intensity strongly varies with the pumping power. A similar glow is observed in opal samples filled with acetone or ethanol.

A new extracellular charged polysaccharide composed mainly by galactose, with lower amounts of mannose, glucose and rhamnose, was produced by the cultivation of Pseudomonas oleovorans NRRL B-14682 using glycerol as the sole carbon source. Thermal and solid-state NMR analysis showed that this polymer is essentially amorphous, with a glass transition temperature of 155.7°C. The exopolysaccharide aqueous solutions have viscoelastic properties similar to that of Guar gum, but with affinity to salts as a result of its polyelectrolyte character. In addition, the exopolysaccharide has demonstrated good flocculating and emulsifying properties and film-forming capacity. These properties make this polymer a good alternative to more expensive natural polysaccharides, such as Guar gum, in several applications in the food, pharmaceutical, cosmetic, textile, paper and petroleum industries.

A single-ISA heterogeneous multi-core architecture is a chip multiprocessor composed of cores of varying size, performance, and complexity. This paper demonstrates that this architecture can provide significantly higher performance in the same area than a conventional chip multiprocessor. It does so by matching the various jobs of a diverse workload to the various cores. This type of architecture covers a spectrum of workloads particularly well, providing high single-thread performance when thread parallelism is low, and high throughput when thread parallelism is high.

Drift wave maps, area preserving maps that describe the motion of charged particles in drift waves, are derived. The maps allow the integration of particle orbits on the long time scale needed to describe transport. Calculations using the drift wave maps show that dramatic improvement in the particle confinement, in the presence of a given level and spectrum of EϫB turbulence, can occur for q(r) profiles with reversed shear. A similar reduction in the transport, i.e., one that is independent of the turbulence, is observed in the presence of an equilibrium radial electric field with shear. The transport reduction, caused by the combined effects of radial electric field shear and both monotonic and reversed shear magnetic q profiles, is also investigated.

Clinical and laboratory evidence indicates that the brain exerts major control on the gastrointestinal tract. Specific brain loci and circuits that send efferent viscerotropic projections to the gut have been described. A variety of aminergic and peptidergic neurotransmitters have been shown to occur along these cerebrogastrointestinal pathways and to influence motor and secretory functions of the gut. Some of the newly identified peptides have been shown to influence the development of gastroduodenal ulcers. Findings with thyrotropin-releasing hormone (TRH) indicate that this endogenous tripeptide induces a full spectrum of gut effects, prominent among which is production of gastric ulcers. By contrast, other peptides including [3-endorphin, neurotensin, and bombesin induce gut effects opposite to those of TRH, namely, inhibition of gastric acid and motility and prevention of experimental ulcers. These laboratory findings suggest that ulcer disease may represent a brain-driven event, which may be the result of a neurochemical imbalance within the brain. Further neurobiological research will generate additional data on brain-gut interactions and will probably disclose new information to explain certain functional and organic disorders of the gut.

Noise can assist neurons in the detection of weak signals via a mechanism known as stochastic resonance ͑SR͒. In a previous study ͓Phys. Lett. A 243, 281 ͑1998͔͒, we showed that when colored noise with 1/f ␤ spectrum is added to the FitzHugh-Nagumo ͑FHN͒ neuronal model, the optimal noise variance for SR could be minimized with ␤Ϸ1. In this study, we investigate analytically how the noise color (␤) affects the SR profile in a linearized version of the FHN model. We demonstrate that the aforementioned effect of 1/f noise is related to the dynamical characteristics of the model neuron, i.e., the refractory period, the low-pass filtering effect of the membrane capacitance, and the high-pass filtering effect of the recovery variable.

The INTEGRAL satellite observed the binary black hole system Cygnus X-1 on 2003 June 7-11. The source was detected up to 800 keV, its spectrum beeing compatible with a power law of photon index 2.3. In the framework of the accreting black hole phenomenology, the source was in an unusual state, probably the so-called ''intermediate state''. Using the results of the analysis performed on these INTEGRAL data, we present here the spectral properties of our observations over the whole energy range covered by the high-energy instruments on board INTEGRAL. We then compare them with those obtained from earlier observations of Cygnus X-1 performed during the INTEGRAL performance and verification phase in the fall of 2002. At that time, the source was found in the low/hard state, indicating that Cygnus X-1 underwent a transition towards a softer state in 2003 June. We discuss the spectral parameters obtained from a Comptonization model.

Objective: Magnetic resonance imaging (MRI) of the ulnar nerve is being increasingly employed in the diagnosis of ulnar neuropathy at the elbow (UNE). Our aims were to: (i) assess the sensitivity of MRI in diagnosing UNE, especially in cases where neurophysiologic studies were non-localizing, (ii) determine the spectrum of MRI abnormalities in patients presenting with symptoms and signs of ulnar neuropathy, (iii) assess whether MRI findings differ between grades of UNE severity, and (iv) to see if MRI findings give an input into the pathological mechanisms of UNE. Methods: Clinical, neurophysiologic, and radiologic (MRI) records were reviewed in 52 patients with symptoms and signs of ulnar neuropathy. Ulnar nerve MRI studies were assessed by an unblinded observer. Results: The sensitivity of MRI at diagnosing UNE was higher than conventional nerve conduction studies, 90 versus 65%, respectively. In patients with non-localizing neurophysiologic studies (nZ19), MRI disclosed changes consistent with UNE in 16 (84%) cases. The most frequent MRI findings included a combination of high signal intensity and nerve enlargement (63%), followed by nerve compression (27%) and isolated high signal intensity (23%), and isolated nerve enlargement (2%). There was no significant difference between patients with localizing and non-localizing neurophysiologic testing. Lastly, there were no differences between different grades of UNE, suggesting that UNE may be a neurophysiologically heterogeneous disorder. Conclusions: MRI studies proved to be more sensitive than conventional nerve conduction studies at diagnosing UNE. In addition, the MRI studies were highly sensitive in patients with non-localizing UNE. Significance: Our study shows that MRI of the ulnar nerve should be used in patients with clinical features of UNE especially in those with non-localizing neurophysiologic testing. q

Four concepts are considered for the trophic level of a species in a community food web. The long-way-uplevel (or LU-level) of species A is the length of the longest simple food chain from a basal species (one with no prey in the web) to A. (A simple chain is a chain that does not pass through any given species more than once.) The short-way-up-level (SU-level) of species A is the length of the shortest chain from a basal species to A. The long-way-down-level (LD-ievel) of species A is the length of the longest simple chain from species A to a top species (one with no consumers in the web). The short-way-down-level (SD-level) of species A is the length of the shortest chain from species A to a top species. The stratigraphy of a web is the analogue for species of the 'pyramid of numbers' for individuals: it is the frequency distribution of species according to level. The LU-, SU-, LD-, and SD-stratigraphies of the seven webs in the Briand-Cohen collection with 30 or more trophic species reveal no species with LU-level or LD-level more than 6, no species with SU-level more than 3, and no species with SD-level more than 2. In all seven webs, SD-levels are stochastically less than SU-levels: species tend to be closer to a top predator than to a basal species. Two stochastic models of food web structure (the cascade model and the homogeneous superlinear model) correctly predict that 95% or more of species should have LU-level and LD-level in the range 0-6. The models also correctly predict some details of the distribution of species in the SU-and SD-stratigraphies, particularly the fraction of species in level 1. The models do not, in general, correctly predict the distribution of species within the range 0-6 of LU-levels and LD-levels.

AbstractÐA new limonoid was isolated from the bark of Khaya senegalensis and identi®ed as 2,6-dihydrox-y®ssinolide. The assignments of some signals in the 13 C NMR spectrum of ®ssinolide have been reversed and the signals of the 1 H NMR spectrum of methyl 3b-acetoxy-6-hydroxy-1-oxomeliac-14-enoate have been assigned. The limonoids only showed moderate antiprotozoal activities. #

A resource allocation framework is presented for spectrum underlay in cognitive radio networks. We consider both interference constraints for primary users and quality of service (QoS) constraints for secondary users. Specifically, interference from secondary users to primary users is constrained to be below a tolerable limit. Also, signal to interference plus noise ratio (SINR) of each secondary user is maintained higher than a desired level for QoS insurance. We propose admission control algorithms to be used during high network load conditions which are performed jointly with power control so that QoS requirements of all admitted secondary users are satisfied while keeping the interference to primary users below the tolerable limit. If all secondary users can be supported at minimum rates, we allow them to increase their transmission rates and share the spectrum in a fair manner. We formulate the joint power/rate allocation with proportional and max-min fairness criteria as optimization problems. We show how to transform these optimization problems into a convex form so that their globally optimal solutions can be obtained. Numerical results show that the proposed admission control algorithms achieve performance very close to that of the optimal solution. Also, impacts of different system and QoS parameters on the network performance are investigated for the admission control, and rate/power allocation algorithms under different fairness criteria.

The microwave limb sounder (MLS) on the Upper Atmosphere Research Satellite (UARS) is the first satellite experiment using limb sounding techniques at microwave frequencies. Primary measurement objectives are stratospheric C10, 03, H20, temperature, and pressure. Measurements are of thermal emission: all are performed simultaneously and continuously and are not degraded by ice clouds or volcanic aerosols. The instrument has a 1.6-m mechanically scanning antenna system and contains heterodyne radiometers in spectral bands centered near 63, 183, and 205 GHz. The radiometers operate at ambient temperature and use Schottky-diode mixers with local oscillators derived from phase-locked Gunn oscillators. Frequency tripling by varactor multipliers generates the 183-and 205-GHz local oscillators, and quasi-optical techniques inject these into the mixers. Six 15-channel filter banks spectrally resolve stratospheric thermal emission lines and produce an output spectrum every 2 s. Thermal stability is sufficient for "total power" measurements which do not require fast chopping. Radiometric calibration, consisting of measurements of cold space and an internal target, is performed every 65-s limb scan. Instrument in-orbit performance has been excellent, and all objectives are being met.