cssi/SciSciGPT-SciSciNet huggingface dataset:
Total Synthesis, Structure Revision, and Absolute Configuration of (+)-Yatakemycin

The total synthesis of the reported structure 2 for yatakemycin, an exceptionally potent, naturally occurring antitumor agent disclosed in 2003, and its lack of correlation with the natural product are detailed. On the basis of spectroscopic distinctions between 2 and yatakemycin, the natural product structure was reformulated as 3, now bearing a thiomethyl ester versus thioacetate in the left-hand subunit. Total synthesis of 3 provided a compound nearly identical to but still subtly distinct from the natural product. A second reformulation of the yatakemycin structure as 1, incorporating the alternatively substituted right-hand subunit as well as the initial thiomethyl ester reformulation, was confirmed by total synthesis of both (+)- and ent-(−)-1 in studies that also unambiguously established the absolute configuration of the natural product.
Angle estimation using a polarization sensitive array

The authors consider using ESPRIT with a polarization-sensitive array to estimate signal directions and polarizations. They also compare the performance of different ways of using ESPRIT with each other and with that of a conventional ESPRIT estimator that does not take polarization into account. >
Analogies between Kruskal Space and de Sitter Space

The relation between Kruskal and Schwarzschild coordinates is analogous to that between hyperboloid and de Sitter coordinates; the Kruskal diagram is analogous to the hyperboloid diagram; and the crossing over of horizons in Kruskal space is analogous to the well-known crossing over of the particle horizon and the event horizon in cosmology.
A neural-network technique for the retrieval of atmospheric temperature and moisture profiles from high spectral resolution sounding data

A novel statistical method for the retrieval of atmospheric temperature and moisture profiles has been developed and evaluated with simulated clear-air and observed partially cloudy sounding data from the Atmospheric InfraRed Sounder (AIRS) and the Advanced Microwave Sounding Unit (AMSU). The algorithm is implemented in two stages. First, a projected principal components (PPC) transform is used to reduce the dimensionality of and optimally extract geophysical profile information from the cloud-cleared infrared radiance data. Second, a multilayer feedforward neural network (NN) is used to estimate the desired geophysical parameters from the PPCs. For the first time, NN temperature and moisture retrievals are presented using actual microwave and hyperspectral infrared observations of cloudy atmospheres, over both ocean and land (with variable terrain elevation), and at all sensor scan angles. The performance of the NN retrieval method (henceforth referred to as the PPC/NN method) was evaluated using global Earth Observing System Aqua orbits colocated with European Center for Medium-range Weather Forecasting fields for seven days throughout 2002 and 2003. Over 350,000 partially cloudy footprints were used in the study, and retrieval performance was compared with the AIRS Science Team Level-2 retrieval algorithm (version 3). Performance compares favorably with that obtained with simulated clear-air observations from the NOAA88b radiosonde set of approximately 7500 profiles. The PPC/NN method requires significantly less computation than traditional variational retrieval methods, while achieving comparable performance.
A holographic c-theorem for Schrödinger spacetimes

We prove a c-theorem for holographic renormalization group flows in a Schrodinger spacetime that demonstrates that the effective radius L(r) monotonically decreases from the UV to the IR, where r is the bulk radial coordinate. This result assumes that the bulk matter satisfies the null energy condition, but holds regardless of the value of the critical exponent z. We also construct several numerical examples in a model where the Schrodinger background is realized by a massive vector coupled to a real scalar. The full Schrodinger group is realized when z = 2, and in this case it is possible to construct solutions with constant effective z(r) = 2 along the entire flow.
Transients in wide-angle conical antennas

The response of an antenna to dc pulse excitation, both in reception and in transmission, can be determined by use of Fourier transforms provided the complex impedance and complex effective height of the antenna are known over the frequency range where the excitation has significant components. We have computed the time history of the response of a wide-angle conical antenna to dc pulse excitation and show the results herein for a matched source in transmission and a matched load in reception for several values of cone angle and antenna length. Under matched conditions, the faithful transmission of a pulse shape, requires a long antenna while faithful reception is not possible. Faithful reception can be achieved by a short antenna with a resistive load of high resistance or with a capacitive load, or by a long antenna with a series RC load. Since this work required transfer functions in transmission and reception, we have also presented here graphs of these quantities.
The Opportunity for Conspiracy in Asset Markets Organized with Dealer Intermediaries

This article reports an asset market experiment in which asymmetrically informed traders transact through competing dealers. Dealers face a classic adverse selection problem, because some traders have private information regarding the asset value while other traders are uninformed. When dealers cannot communicate outside the market, they price the asset competitively and the market is generally informationally efficient. When dealers communicate privately between periods, they collude successfully to widen spreads and increase profit. Another treatment permits traders to post limit orders, while still allowing dealers to communicate. Limit orders restore informational efficiency and narrow spreads but cause dealers to earn negative trading profits.
Friends in High Places

We demonstrate that personal connections amongst US politicians have a significant impact on Senate voting behavior. Networks based on alumni connections between politicians are consistent predictors of voting behavior. We estimate sharp measures that control for common characteristics of the network, as well as heterogeneous impacts of a common network characteristic across votes. We find that the effect of alumni networks is close to 60 percent as large as the effect of state-level considerations. We show that politicians use school ties as a mechanism to engage in vote trading ("logrolling"), and that alumni networks help facilitate the procurement of discretionary earmarks.
The impact of diversification strategy on risk-return performance

This study examines the impact of diversification strategy on risk and return in diversified firms. Following an assessment of previous research on strategic risk, relationships between risk, return, and diversification strategy are hypothesized. Regression analysis shows that differences in risk-return performance among diversified firms are more closely associated with structural factors associated with markets and businesses than with the particular diversification strategy chosen. Returns also influence the choice of diversification strategles which, in turn, do not get rewarded with higher profits. A curvilinear risk-return relationship is also observed which is consistent with previous theoretical suggestions. Implications for the strategic management of risk are then drawn.
Absolute energy calibration with the neutron-activated liquid-source system at BABAR's CsI(Tl) calorimeter

The electro-magnetic calorimeter at the BABAR detector, part of the asymmetric B Factory at SLAC, measures photons in the energy range from 20 MeV to 8 GeV with good resolution. The calorimeter is calibrated at the low energy end with 6.13 MeV photons obtained from a liquid source system. During the calibration, a fluorine-rich liquid is activated via a neutron generator and pumped past the front of the calorimeter's crystals. Decays that occur in front of the crystals emit photons of well-defined energy, which are detected in the crystals with the regular data acquisition system. The liquid source system adds only very little material in front of the calorimeter, needs nearly no maintenance, and allows operation at the switch of a key with minimal safety hazards. The report describes the system, presents calibration results obtained from its operation since 1999, shows the crystals' loss of light yield due to radiation damage, and shares experiences gained over the years.
FINITE MIXTURE ESTIMATION OF SIZE ECONOMIES AND COST FRONTIERS IN THE FACE OF MULTIPLE PRODUCTION TECHNOLOGIES

Finite mixture estimation (FME) is compared to estimated generalized least squares (EGLS) in the estimation of economies of size and production cost frontiers for Alabama dairy farms. FME provides several unique insights into the economic forces behind recent changes in Alabama’s dairy industry. FME provides estimation of a stochastic average cost frontier with known statisticalproperties, which it was not otherwise possible to obtain using available stochastic frontier estimation packages.
A CURE FOR CRIME? PSYCHO-PHARMACEUTICALS AND CRIME TRENDS

In this paper we consider possible links between the diffusion of new pharmaceuticals used for treating mental illness and crime rates. We describe recent trends in crime and review the evidence showing that mental illness is a clear risk factor both for criminal behavior and victimization. We summarize the development of a number of new pharmaceutical therapies for the treatment of mental illness that came into wide use during the "great American crime decline." We examine limited international data, as well as more detailed American data, to assess the relationship between rates of prescriptions of psychotropic drugs and crime rates, while controlling for other factors that may explain trends in crime rates. Using state-level variation in the rates that various drug therapies disperse within populations to identify impacts on crime rates, we find some evidence that the expansion of psychiatric drugs is associated with decreased violent crime rates, but not property crime rates. We find no robust impacts on homicide rates and no effects on arrest rates. Further, the magnitudes of the estimated effects of expanded drug treatment on violent crime are small. Our estimates imply that about 5 percent of the decline in crime during the period of our study was due to expanded mental health treatment. © 2010 by the Association for Public Policy Analysis and Management. Language: en
Is a guaranteed living wage a good anti-poverty policy?

Minimum wages are generally thought to be unenforceable in developing rural economies. But there is one solution - a workfare scheme in which the government acts as the employer of last resort. Is this a cost-effective policy against poverty? Using a microeconometric model of the casual labor market in rural India, the authors find that a guaranteed wage rate sufficient for a typical poor family to reach the poverty line would bring the annual poverty rate down from 34 percent to 25 percent at a fiscal cost representing 3-4 percent of GDP when run for the whole year. Confining the scheme to the lean season (three months) would bring the annual poverty rate down to 31 percent at a cost of 1.3 percent of GDP. While the gains from a guaranteed wage rate would be better targeted than a uniform (untargeted) cash transfer, the extra costs of the wage policy imply that it would have less impact on poverty.
Feasibility of using time–space prism to represent available opportunities and choice sets for destination choice models in the context of dynamic urban environments

Hagerstrand’s original framework of time geography and the subsequent time–space prism computational methods form the foundation of a new computational method for potential path areas (PPA) in a realistic representation of dynamic urban environments. In this paper the time–space prism framework is used to assess sensitivity of PPA size to different parameters and to build choice sets for regional destination choice models. We explain the implication of different parameters to choice set formation in a step-wise manner and illustrate not only the complexity of the idea and the high computational demand but also behavioral realism. In this context, this paper tests the feasibility of using constraint-based time–space prism to find the choice sets for a large-scale destination choice model, and identifies a variety of implementation issues. Computational demand is estimated based on a household travel survey for the Southern California Association of Government, and the feasibility of using time–space prisms for destination choice models is assessed with different levels of information on the network and destinations available. The implications of time of day effects and flexibility in scheduling on choice set development due to varying level of service on the network and availability of activity opportunities are discussed and numerically assessed.
Initial Results from the Palomar Adaptive Optics Survey of Young Solar-Type Stars: A Brown Dwarf and Three Stellar Companions

We present first results from the Palomar Adaptive Optics Survey of Young Stars conducted at the Hale 5 m telescope. Through direct imaging we have discovered a brown dwarf and two low-mass stellar companions to the young solar-type stars HD 49197, HD 129333 (EK Dra), and V522 Per and confirmed a previously suspected companion to RX J0329.1+0118 (Sterzik et al.), at respective separations of 0."95 (43 AU), 0."74 (25 AU), 2."09 (400 AU), and 3."78 (380 AU). Physical association of each binary system is established through common proper motion and/or low-resolution infrared spectroscopy. Based on the companion spectral types, we estimate their masses at 0.06, 0.20, 0.13, and 0.20 M_☉, respectively. From analysis of our imaging data combined with archival radial velocity data, we find that the spatially resolved companion to HD 129333 is potentially identical to the previously identified spectroscopic companion to this star (Duquennoy & Mayor). However, a discrepancy with the absolute magnitude suggests that the two companions could also be distinct, with the resolved one being the outermost component of a triple system. The brown dwarf HD 49197B is a new member of a growing list of directly imaged substellar companions at 10-1000 AU separations from main-sequence stars, indicating that such brown dwarfs may be more common than initially speculated.
Test-suite reduction and prioritization for modified condition/decision coverage

Software testing is particularly expensive for developers of high-assurance software, such as software that is produced for commercial airborne systems. One reason for this expense is the Federal Aviation Administration's requirement that test suites be modified condition/decision coverage (MC/DC) adequate. Despite its cost, there is evidence that MC/DC is an effective verification technique and can help to uncover safety faults. As the software is modified and new test cases are added to the test suite, the test suite grows and the cost of regression testing increases. To address the test-suite size problem, researchers have investigated the use of test-suite reduction algorithms, which identify a reduced test suite that provides the same coverage of the software according to some criterion as the original test suite, and test-suite prioritization algorithms, which identify an ordering of the test cases in the test suite according to some criteria or goals. Existing test-suite reduction and prioritization techniques, however, may not be effective in reducing or prioritizing MC/DC-adequate test suites because they do not consider the complexity of the criterion. This paper presents new algorithms for test-suite reduction and prioritization that can be tailored effectively for use with MC/DC. The paper also presents the results of empirical studies of these algorithms.
Ordered mesoporous silica-based inorganic nanocomposites

This article reviews the synthesis and characterization of nanoparticles and nanowires grown in ordered mesoporous silicas (OMS). Summarizing work performed over the last 4 years, this article highlights the material properties of the final nanocomposite in the context of the synthesis methodology employed. While certain metal-OMS systems (e.g. gold in MCM-41) have been extensively studied this article highlights that there is a rich set of chemistries that have yet to be explored. The article concludes with some thoughts on future developments and challenges in this area.
Compactification of the moduli space of hyperplane arrangements

Consider the moduli space M 0 of arrangements of n hyperplanes in general position in projective (r − 1)-space. When r =2t he space has a compactification given by the moduli space of stable curves of genus 0 with n marked points. In higher dimensions, the analogue of the moduli space of stable curves is the moduli space of stable pairs: pairs (S, B) consisting of a variety S (possibly reducible) and a divisor B = B1 + ··· + Bn, satisfying various additional conditions. We identify the closure of M 0 in the moduli space of stable pairs as Kapranov’s Hilbert quotient compactification of M 0 , and give an explicit description of the pairs at the boundary. We also construct additional irreducible components of the moduli space of stable pairs.
Radio remote sensing of the corona and the solar wind

Modern radio telescopes are extremely sensitive to plasma on the line of sight from a radio source to the antenna. Plasmas in the corona and solar wind produce measurable changes in the radio wave amplitude and phase, and the phase difference between wave fields of opposite circular polarization. Such measurements can be made of radio waves from spacecraft transmitters and extragalactic radio sources, using radio telescopes and spacecraft tracking antennas. Data have been taken at frequencies from about 80 MHz to 8000 MHz. Lower frequencies probe plasma at greater heliocentric distances. Analysis of these data yields information on the plasma density, density fluctuations, and plasma flow speeds in the corona and solar wind, and on the magnetic field in the solar corona. This paper will concentrate on the information that can be obtained from measurements of Faraday rotation through the corona and inner solar wind. The magnitude of Faraday rotation is proportional to the line of sight integral of the plasma density and the line-of-sight component of the magnetic field. Faraday rotation provides an almost unique means of estimating the magnetic field in this part of space. This technique has contributed to measurement of the large scale coronal magnetic field, the properties of electromagnetic turbulence in the corona, possible detection of electrical currents in the corona, and probing of the internal structure of coronal mass ejections (CMEs). This paper concentrates on the search for small-scale coronal turbulence and remote sensing of the structure of CMEs. Future investigations with the Expanded Very Large Array (EVLA) or Murchison Widefield Array (MWA) could provide unique observational input on the astrophysics of CMEs.
Efficient and robust feature extraction by maximum margin criterion

In pattern recognition, feature extraction techniques are widely employed to reduce the dimensionality of data and to enhance the discriminatory information. Principal component analysis (PCA) and linear discriminant analysis (LDA) are the two most popular linear dimensionality reduction methods. However, PCA is not very effective for the extraction of the most discriminant features, and LDA is not stable due to the small sample size problem . In this paper, we propose some new (linear and nonlinear) feature extractors based on maximum margin criterion (MMC). Geometrically, feature extractors based on MMC maximize the (average) margin between classes after dimensionality reduction. It is shown that MMC can represent class separability better than PCA. As a connection to LDA, we may also derive LDA from MMC by incorporating some constraints. By using some other constraints, we establish a new linear feature extractor that does not suffer from the small sample size problem, which is known to cause serious stability problems for LDA. The kernelized (nonlinear) counterpart of this linear feature extractor is also established in the paper. Our extensive experiments demonstrate that the new feature extractors are effective, stable, and efficient.
Non-biomimetic route to deoxyadenosine adducts of carcinogenic polycyclic aromatic hydrocarbons

Aminotriols are prepared by direct aminolysis of the diol epoxides of polycyclic aromatic hydrocarbons, providing a substantial improvement over literature methods. The condensation of aminotriols with 6-halopurine deoxyribonucleosides provides a regio- and stereospecific synthesis of deoxyadenosine N6 adducts.
Differential RAID: rethinking RAID for SSD reliability

Deployment of SSDs in enterprise settings is limited by the low erase cycles available on commodity devices. Redundancy solutions such as RAID can potentially be used to protect against the high Bit Error Rate (BER) of aging SSDs. Unfortunately, such solutions wear out redundant devices at similar rates, inducing correlated failures as arrays age in unison. We present Diff-RAID, a new RAID variant that distributes parity unevenly across SSDs to create age disparities within arrays. By doing so, Diff-RAID balances the high BER of old SSDs against the low BER of young SSDs. Diff-RAID provides much greater reliability for SSDs compared to RAID-4 and RAID-5 for the same space overhead, and offers a trade-off curve between throughput and reliability.
ON THE NATURE OF THE RADIAL VELOCITY VARIABILITY OF ALDEBARAN : A SEARCH FOR SPECTRAL LINE BISECTOR VARIATIONS

The shape of the Ti i 6303.8-A spectral line of Aldebaran as measured by the line bisector was investigated using high signal-to-noise ratio, high-resolution data. The goal of this study was to understand the nature of the 643-d period in the radial velocity for this star reported by Hatzes & Cochran. Variations in the line bisector with the radial velocity period would provide strong evidence in support of rotational modulation or stellar pulsations as the cause of the 643-d period. A lack of any bisector variability at this period would support the planet hypothesis. Variations in the line asymmetries are found with a period of 49.93 d. These variations are uncorrelated with the 643-d period found previously in the radial velocity measurements. It is demonstrated that this 50-d period is consistent with an m=4 non-radial sectoral g-mode oscillation. The lack of spectral variability with the radial velocity period of 643 d may provide strong evidence in support of the hypothesis that this variability stems from the reflex motion of the central star due to a planetary companion having a mass of 11 Jupiter masses. However, this long-period variability may still be the result of a low-order (m=2) pulsation mode as these would cause bisector variations of less than the error measurement.
Diffusion in Fluid Flow: Dissipation Enhancement by Flows in 2D

We consider the advection-diffusion equation on ℝ2, with u a periodic incompressible flow and A ≫ 1 its amplitude. We provide a sharp characterization of all u that optimally enhance dissipation in...
A Descriptive Analysis of Discrete U.S. Industrial Complexes

We use the Getis/Ord local G statistic and detailed county-level industry employment data from the U.S. Bureau of Labor Statistics to isolate discrete industrial complexes-or groups of nominally linked industries clustered in particular locations-for two recent years: 1989 and 1997. We describe the characteristics of the complexes in terms of their number, spatial extent, broad regional distribution, and other factors. Data from the two periods help illustrate key shifts in industrial locations, including the continuing concentration of the apparel industry in the Southeast and the ongoing southern shift in U.S. vehicle production.
Using gradual numbers to analyze non-monotonic functions of fuzzy intervals

Gradual numbers have been introduced recently as a means of extending standard interval computation methods to fuzzy intervals. The literature treats monotonic functions of fuzzy intervals. In this paper, we combine the concepts of gradual numbers and optimization, which allows for the evaluation of any differentiable function on fuzzy intervals, with no monotonicity requirement.
Rates of Convergence for Nearest Neighbor Classification

We analyze the behavior of nearest neighbor classification in metric spaces and provide finite-sample, distribution-dependent rates of convergence under minimal assumptions. These are more general than existing bounds, and enable us, as a by-product, to establish the universal consistency of nearest neighbor in a broader range of data spaces than was previously known. We illustrate our upper and lower bounds by introducing a new smoothness class customized for nearest neighbor classification. We find, for instance, that under the Tsybakov margin condition the convergence rate of nearest neighbor matches recently established lower bounds for nonparametric classification.
Simulation of coupled bunch mode growth driven by a high-Q resonator: a transient response approach

The use of a longitudinal phase-space tracking code, ESME, to simulate the growth of a coupled-bunch instability in the Fermilab Booster is examined. The calculation of the resonant response is described. Two simulations are presented. In the first, all 84 RF buckets are populated with a bi-Gaussian distribution of emittance of 0.02 eV-s. Each bunch is represented by 100 macro-particles. The entire distribution (the ring) is divided into 3000 bins for the purposes of computing and applying the voltage due to the resonance. The charge corresponding to each bunch is set to 6.6*10/sup 12/ protons. In the second simulation, the parameters are the same as in the first, except for the fact that five buckets are not initially populated. The absence of these bunches enhanced the growth of the mode considerably. The induced voltage in the second case rises to an amplitude an order of magnitude larger than the first, 200 kV vs. 7 kV. The larger growth of the mode in the gapped-beam case may be caused by the enhancement of the harmonic component of the current at mode 56 initially, whereas in the symmetrical case the instability grows out of noise. >
Fluorescence lifetime spectroscopy in multiply scattering media

In vivo analytical sensing using fluorescence spectroscopy is complicated not only by the scattering of tissue, but also by the fact that most sensing fluorophores do not exhibit single exponential decay lifetime. Herein, we present a study that underscore the sensitivity of lifetime spectroscopy in tissue-like scattering media by comparisons of measurements made on a mixture of two dyes in Intralipid solution to the predictions incorporating optical diffusion equation and various decay kinetics model. In addition, this work extends fluorescence sensing to dyes whose relaxation kinetics are described not only by first order kinetics but by more complex kinetics owing to quenching and multiple activated states of the sensing dye.
Orbital Formationkeeping with Differential Drag

This paper examines the feasibility of using differential drag between two spacecraft as the means for controlling their relative positions. The equations ofirelative motion between two satellites are derived and a coordinate transformation is made to reduce the formationkeeping problem to the simultaneous solution of a double integrator and a harmonic oscillator. A simple feedback control law is developed that simultaneously and dependently solves the double integrator and harmonic oscillator; the control law consists of two parts: the main control law and the eccentricity minimizing control scheme. Results are presented of four test cases which show that the control law can drive a satellite from an initial position to a target position and maintain the satellite at that location.
Volume fractions of the kinematic 'near-critical' sets of the quantum ensemble control landscape

An estimate is derived for the volume fraction of a subset C P ={ U : � grad J( U )� � }⊂ U(N) in the neighborhood of the critical set C PU(n)PU(m) of the kinematic quantum ensemble control landscape J( U )= Tr(UρU † O), where U represents the unitary time evolution operator, ρ is the initial density matrix of the ensemble, and O is an observable operator. This estimate is based on the Hilbert-Schmidt geometry for the unitary group and a first-order approximation ofgrad J( U )� 2 . An upper bound on these near-critical volumes is conjectured and supported by numerical simulation, leading to an asymptotic analysis as the dimension N of the quantum system rises in which the volume fractions of these 'near-critical' sets decrease to zero as N increases. This result helps explain the apparent lack of influence exerted by the many saddles of J over the gradient flow.
Bayesian source separation and localization

The problem of mixed signals occurs in many different contexts; one of the most familiar being acoustics. The forward problem in acoustics consists of finding the sound pressure levels at various detectors resulting from sound signals emanating from the active acoustic sources. The inverse problem consists of using the sound recorded by the detectors to separate the signals and recover the original source waveforms. In general, the inverse problem is unsolvable without additional information. This general problem is called source separation, and several techniques have been developed that utilize maximum entropy, minimum mutual information, and maximum likelihood. In previous work, it has been demonstrated that these techniques can be recast in a Bayesian framework. This paper demonstrates the power of the Bayesian approach, which provides a natural means for incorporating prior information into a source model. An algorithm is developed that utilizes information regarding both the statistics of the amplitudes of the signals emitted by the sources and the relative locations of the detectors. Using this prior information, the algorithm finds the most probable source behavior and configuration. Thus, the inverse problem can be solved by simultaneously performing source separation and localization. It should be noted that this algorithm is not designed to account for delay times that are often important in acoustic source separation. However, a possible application of this algorithm is in the separation of electrophysiological signals obtained using electroencephalography (EEG) and magnetoencephalography (MEG).
A bit of progress in language modeling

In the past several years, a number of different language modeling improvements over simple trigram models have been found, including caching, higher-order n -grams, skipping, interpolated Kneser?Ney smoothing, and clustering. We present explorations of variations on, or of the limits of, each of these techniques, including showing that sentence mixture models may have more potential. While all of these techniques have been studied separately, they have rarely been studied in combination. We compare a combination of all techniques together to a Katz smoothed trigram model with no count cutoffs. We achieve perplexity reductions between 38 and 50% (1 bit of entropy), depending on training data size, as well as a word error rate reduction of 8.9%. Our perplexity reductions are perhaps the highest reported compared to a fair baseline.
Provably correct runtime enforcement of non-interference properties

Non-interference has become the standard criterion for ensuring confidentiality of sensitive data in the information flow literature. However, application of non-interference to practical software systems has been limited. This is partly due to the imprecision that is inherent in static analyses that have formed the basis of previous non-interference based techniques. Runtime approaches can be significantly more accurate than static analysis, and have often been more successful in practice. However, they can only reason about explicit information flows that take place via assignments in a program. Implicit flows that take place without involving assignments, and can be inferred from the structure and/or semantics of the program, are missed by runtime techniques. This paper seeks to bridge the gap between the accuracy provided by runtime techniques and the completeness provided by static analysis techniques. In particular, we develop a hybrid technique that relies primarily on runtime information-flow tracking, but augments it with static analysis to reason about implicit flows that arise due to unexecuted paths in a program. We prove that the resulting technique preserves non-interference, while providing some of the traditional benefits of dynamic analysis such as improved accuracy.
Self-duality, helicity and background field loopology

I show that helicity plays an important role in the development of rules for computing higher loop effective Lagrangians. Specifically, the two-loop Heisenberg-Euler effective Lagrangian in quantum electrodynamics is remarkably simple when the background field has definite helicity (i.e., is self-dual). Furthermore, the twoloop answer can be derived essentially algebraically, and is naturally expressed in terms of one-loop quantities. This represents a generalization of the familiar “integration-by-parts’’ rules for manipulating diagrams involving free propagators to the more complicated case where the propagators are those for scalars or spinors in the presence of a background field.
A mild and efficient route to the pharmacophore of the enediyne antitumor agents : (Z)-1,6-[bis (trimethylsilyl)]-hex-3-ene-1,5-diyne via a novel carbenoid coupling reaction

(Z)-1,6-[Bis (trimethylsilyl)]-hex-3-ene-1,5-diyne has been prepared in high yield and in one pot from trimethylsilylpropargyl bromide by a remarkably stereoselective tandem carbenoid coupling-HX elimination sequence.
Overview of non-liquid noble direct detection dark matter experiments

In the last few years many advances have been made in the field of dark matter direct detection. In this article I will review the progress and status of experiments that employ detection techniques that do not use noble liquids. First, I will give an introduction to the field of dark matter and discuss the background challenges that confront all dark matter experiments. I will also discuss various detection techniques employed by the current generation and the next generation of dark matter experiments. Finally, I will discuss recent results and the status of current and future direct detection experiments.
Metal fume fever presenting as aseptic meningitis with pericarditis, pleuritis and pneumonitis.

Background Metal fume fever (MFF) is a well-known complication of zinc oxide fume inhalation. Prompt recognition of this condition is essential for the proper medical management of this self-limited disease. Aim To present a unique and unusual case of MFF. Results Our patient is a 25-year-old male welder who had MFF and presented with aseptic meningitis with pericarditis, pleuritis and pneumonitis. To our knowledge, this is the first case of MMF presenting with these signs and symptoms. Conclusions MFF can present with a systemic inflammatory response causing a multi-organ serositis. Our case highlights the utmost importance of obtaining an occupational history on all our patients, even if they are critically ill.
Connectomic constraints on computation in feedforward networks of spiking neurons

Several efforts are currently underway to decipher the connectome or parts thereof in a variety of organisms. Ascertaining the detailed physiological properties of all the neurons in these connectomes, however, is out of the scope of such projects. It is therefore unclear to what extent knowledge of the connectome alone will advance a mechanistic understanding of computation occurring in these neural circuits, especially when the high-level function of the said circuit is unknown. We consider, here, the question of how the wiring diagram of neurons imposes constraints on what neural circuits can compute, when we cannot assume detailed information on the physiological response properties of the neurons. We call such constraints--that arise by virtue of the connectome--connectomic constraints on computation. For feedforward networks equipped with neurons that obey a deterministic spiking neuron model which satisfies a small number of properties, we ask if just by knowing the architecture of a network, we can rule out computations that it could be doing, no matter what response properties each of its neurons may have. We show results of this form, for certain classes of network architectures. On the other hand, we also prove that with the limited set of properties assumed for our model neurons, there are fundamental limits to the constraints imposed by network structure. Thus, our theory suggests that while connectomic constraints might restrict the computational ability of certain classes of network architectures, we may require more elaborate information on the properties of neurons in the network, before we can discern such results for other classes of networks.
Revised Annotations, Sex-Biased Expression, and Lineage-Specific Genes in the Drosophila melanogaster Group

Here, we provide revised gene models for D. ananassae, D. yakuba, and D. simulans, which include untranslated regions and empirically verified intron-exon boundaries, as well as ortholog groups identified using a fuzzy reciprocal-best-hit blast comparison. Using these revised annotations, we perform differential expression testing using the cufflinks suite to provide a broad overview of differential expression between reproductive tissues and the carcass. We identify thousands of genes that are differentially expressed across tissues in D. yakuba and D. simulans, with roughly 60% agreement in expression patterns of orthologs in D. yakuba and D. simulans. We identify several cases of putative polycistronic transcripts, pointing to a combination of transcriptional read-through in the genome as well as putative gene fusion and fission events across taxa. We furthermore identify hundreds of lineage specific genes in each species with no blast hits among transcripts of any other Drosophila species, which are candidates for neofunctionalized proteins and a potential source of genetic novelty.
Time to Work or Time to Play: The Effect of Student Employment on Homework, Sleep, and Screen Time

Abstract We use detailed time-diary information on high school students’ daily activities from the 2003–2008 American Time Use Surveys (ATUS) to investigate the effects of employment on the time a student spends on homework and other major activities. Time-diary data are more detailed and accurate than data derived from responses to “usual activity” survey questions underlying other analyses and capture the immediate effects of working that may well accumulate over time to affect future outcomes. Our results suggest that employment decreases the time that high school students spend on homework, which is human-capital building, on all days, but also decreases screen time on non-school days, which may be considered unproductive time. Employed teens get more than the recommended amount of sleep on school days, and only slightly less on non-school days.
Rule ordering in bottom-up fixpoint evaluation of logic programs

Logic programs can be evaluated bottom-up by repeatedly applying all rules, in "iterations", until the fixpoint is reached. However, it is often desirable-and, in some cases, e.g. programs with stratified negation, it is even necessary to guarantee the semantics-to apply the rules in some order. We present two algorithms that apply rules in a specified order without repeating inferences. One of them (GSN) is capable of dealing with a wide range of rule orderings, but with a little more overhead than the well-known seminaive algorithm (which we call BSN). The other (PSN) handles a smaller class of rule orderings, but with no overheads beyond those in BSN. We also demonstrate that by choosing a good ordering, we can reduce the number of rule applications (and thus the number of joins). We present a theoretical analysis of rule orderings and identify orderings that minimize the number of rule applications (for all possible instances of the base relations) with respect to a class of orderings called fair orderings. We also show that though nonfair orderings may do a little better on some data sets, they can do much worse on others. The analysis is supplemented by performance results. >
Continuous Forecasting and Evaluation of Derived Z-R Relationships in a Sparse Rain Gauge Network Using NEXRAD

AbstractDistributed rainfall information is necessary for making operational hydrologic predictions and retrospective studies. Rainfall measurements from radar require conversion of reflectivity into rainfall rates, but contain systematic errors (bias). Default Z-R relationships that are commonly used are not adapted to particular radars and vary by season. Improved rainfall estimation may be obtained for a given season and radar installation by deriving Z-R relationships. These derived Z-R relationships are used before prospective storms cross over gauges within a network, i.e., before near real-time bias corrections are possible. This research focuses on the derivation of Z-R relationships for rainfall estimation in the South Florida Water Management District. These relationships are derived through seasonal characterization of gauge and Next-Generation Radar (NEXRAD) system observations. Verification of the derived Z-R relationships is evaluated using rain gauges withheld for cross validation. Methods ...
On the spherical derivative of a rational function

For a rational function $$f$$ we consider the norm of the derivative with respect to the spherical metric and denote by $$K(f)$$ the supremum of this norm. We give estimates of this quantity $$K(f)$$ both for an individual function and for sequences of iterates.
Vibrational Energy Flow and Chemical Reactions

How vibrational energy flows in molecules has recently become much better understood through the joint efforts of theory, experiment, and computation. The phenomenology of energy flow is much richer than earlier thought. We now know energy flow depends on the local structure of molecular vibrational state space. The details of the theoretically predicted transition from localized vibrations to free flow, where the molecule can act as its own heat bath, are now well-established experimentally. Energy flow is a quantum diffusive process leading to nonexponential decays, also seen in experiment. The slowness of energy flow in activated molecules causes substantial deviation from statistical Rice−Ramsperger−Kassel−Marcus (RRKM) theories for low barrier rate processes, such as isomerization. Quantitative calculations of rates in those cases are now possible.
The relation between optical extinction and hydrogen column density in the Galaxy

A linear relation between the hydrogen column density (N H ) and optical extinction (A v ) in the Galaxy has long been observed. A number of studies found differing results in the slope of this relation. Here, we utilize the data on 22 supernova remnants that have been observed with the latest generation X-ray observatories and for which optical extinction and/or reddening measurements have been performed and find N H (cm -2 ) = (2.21 ± 0.09) x 10 21 Av (mag). We compare our result with the previous studies and assess any systematic uncertainties that may affect these results.
Localized asynchronous packet scheduling for buffered crossbar switches

Buffered crossbar switches are a special type of crossbar switches. In such a switch, besides normal input queues and output queues, a small buffer is associated with each crosspoint. Due to the introduction of crosspoint buffers, output and input contention is eliminated, and the scheduling process for buffered crossbar switches is greatly simplified. Moreover, crosspoint buffers enable the switch to work in an asynchronous mode and easily schedule and transmit variable length packets. Compared with fixed length packet scheduling or cell scheduling, variable length packet scheduling, or packet scheduling for short, has some unique advantages: higher throughput, shorter packet latency and lower hardware cost. In this paper, we present a fast and practical scheduling scheme for buffered crossbar switches called Localized Asynchronous Packet Scheduling (LAPS). With LAPS, an input port or output port makes scheduling decisions solely based on the state information of its local crosspoint buffers, i.e., the crosspoint buffers where the input port sends packets to or the output port retrieves packets from. The localization property makes LAPS suitable for a distributed implementation and thus highly scalable. Since no comparison operation is required in LAPS, scheduling arbiters can be efficiently implemented using priority encoders, which can make arbitration decisions quickly in hardware. Another advantage of LAPS is that each crosspoint needs only L (the maximum packet length) buffer space, which minimizes the hardware cost of the switches. We also theoretically analyze the performance of LAPS, and in particular we prove that LAPS achieves 100% throughput for any admissible traffic with speedup of two. Finally, simulations are conducted to verify the analytical results and measure the performance of LAPS.
Supercritical Fluid Technologies for Ceramic-Processing Applications

This paper reports on the applications of supercritical fluid technologies for ceramic processing. The physical and chemical properties of these densified gases are summarized and related to their use as solvents and processing media. Several areas are identified in which specific ceramic processes benefit from the unique properties of supercritical fluids. The rapid expansion of supercritical fluid solutions provides a technique for producing fine uniform powders and thin films of widely varying materials. Supercritical drying technologies allow the formation of highly porous aerogel products with potentially wide application. Hydrothermal processes leading to the formation of large single crystals and microcrystalline powders can also be extended into the supercritical regime of water. Additional applications and potential applications are identified in the areas of extraction of binders and other additives from ceramic compacts, densification of porous ceramics, the formation of powders in supercritical micro-emulsions, and in preceramic polymer processing.
Molecular Electronics with Carbon Nanotubes

Carbon nanotubes have unique properties that make them a most promising system on which to base molecular electronics. We briefly review the electrical characteristics of carbon nanotubes, and then focus on carbon nanotube field-effect transistors (CNTFETs). Procedures by which hole-transport, electron-transport and ambipolar CNTFETs can be fabricated are presented, and their electrical characteristics are discussed and compared with those of Si MOSFETs. Ways to fabricate arrays of CNTFETs are also demonstrated, and electron and hole CNTFETs are integrated to form complementary logic circuits.