cssi/SciSciGPT-SciSciNet huggingface dataset:
Spectral representations for convolutional neural networks

Discrete Fourier transforms provide a significant speedup in the computation of convolutions in deep learning. In this work, we demonstrate that, beyond its advantages for efficient computation, the spectral domain also provides a powerful representation in which to model and train convolutional neural networks (CNNs). We employ spectral representations to introduce a number of innovations to CNN design. First, we propose spectral pooling, which performs dimensionality reduction by truncating the representation in the frequency domain. This approach preserves considerably more information per parameter than other pooling strategies and enables flexibility in the choice of pooling output dimensionality. This representation also enables a new form of stochastic regularization by randomized modification of resolution. We show that these methods achieve competitive results on classification and approximation tasks, without using any dropout or max-pooling. Finally, we demonstrate the effectiveness of complex-coefficient spectral parameterization of convolutional filters. While this leaves the underlying model unchanged, it results in a representation that greatly facilitates optimization. We observe on a variety of popular CNN configurations that this leads to significantly faster convergence during training.
Crossover from quantum to classical transport

Understanding the crossover from quantum to classical transport has become of fundamental importance not only for technological applications due to the creation of sub-10-nm transistors – an important building block of our modern life – but also for elucidating the role played by quantum mechanics in the evolutionary fitness of biological complexes. This article provides a basic introduction into the nature of charge and energy transport in the quantum and classical regimes. It discusses the characteristic transport properties in both limits and demonstrates how they can be connected through the loss of quantum mechanical coherence. The salient features of the crossover physics are identified, and their importance in opening new transport regimes and in understanding efficient and robust energy transport in biological complexes are demonstrated.
A clinical and histopathologic study of lesions of the cervix uteri during pregnancy.

Abstract This report is an analysis of eighty-nine specimens obtained from the cervix uteri in a group of women at all stages of gestation. Four were obtained by hysterectomy and the others by removal of a lesion recognized grossly or by a biopsy of the cervix. Gross and histopathologic examination revealed that mucous polyps of the cervix were found in thirty-seven, erosion of the cervix in thirty-two, carcinoma of the cervix in ten, condyloma acuminata in five, endometrial polyps in three, and leucoplakia in two. A histopathologic analysis of thirty-two so-called “erosions of the cervix” extensive enough to warrant obtaining a biopsy specimen, suggests that this lesion should be considered as an adenoma of the cervix rather than an inflammatory condition. As a matter of record, some details are given of the ten cases of carcinoma of the cervix uteri seen during pregnancy in the Department of Obstetrics and Gynecology of the Stanford Medical School.
Health system strengthening: new potential for public health and human rights collaboration.

Is pregnancy getting safer for women? It depends. It depends on where a woman is born her social class ethnic group or other marker of social and geographic positioning. While specific changes in medical techniques or fashions may theoretically improve or worsen the risks for individual women everywhere from a public health perspective maternal mortality remains the indicator of population health that reveals most starkly the profound inequities of our time. For decades now estimates of lifetime risk of maternal death have captured the gulf between women in the poorest countries and those in the wealthiest: in sub-Saharan Africa women have a lifetime risk of 1 in 16 of dying in pregnancy and childbirth while in Europe they run a dramatically lower risk of 1 in 2400. Newer techniques use data from Demographic and Health Surveys to estimate disparities within countries between the highest and lowest wealth quintiles with analyses showing as much as a six-fold difference in maternal mortalityratios. There is a critical distinction between countries with "massive deprivation" (in which the elites have access while the great majority of the population is excluded) and countries with "marginal exclusion" (in which most of the population has access while only the poorest most disadvantaged are excluded). This distinction helps put the disparity between the highest and lowest quintiles into overall perspective and clarifies the nature of underlying systemic failures - and the very different strategies needed to tackle them. (excerpt)
Simultaneous resolution of singularities

We prove a local theorem on simultaneous resolution of singularities, which is valid in all dimensions. This theorem is proven in dimension 2 (and in all characteristics) by Abhyankar in his book "Ramification theoretic methods in algebraic geometry" (1959).
The Topology of Bendless Three-Dimensional Orthogonal Graph Drawing

We define an xyz graph to be a spatial embedding of a 3-regular graph such that the edges at each vertex are mutually perpendicular and no three points lie on an axis-parallel line. We describe an equivalence between xyz graphs and 3-face-colored polyhedral maps, under which bipartiteness of the graph is equivalent to orientability of the map. We show that planar graphs are xyz graphs if and only if they are bipartite, cubic, and three-connected. It is NP-complete to recognize xyz graphs, but we show how to do this in time O (n 2 n /2).
Quasistatic and Pulsed Current-Induced Switching With Spin-Orbit Torques in Ultrathin Films With Perpendicular Magnetic Anisotropy

Spin-orbit interaction derived spin torques provide a means of reversing the magnetization of perpendicularly magnetized ultrathin films with currents that flow in the plane of the layers. A basic and critical question for applications is the speed and efficiency of switching with nanosecond current pulses. Here, we investigate and contrast the quasistatic (slowly swept current) and pulsed current-induced switching characteristics of micrometer scale Hall crosses consisting of very thin ( $ nm) perpendicularly magnetized CoFeB layers on $\beta$ -Ta. While complete magnetization reversal occurs at a threshold current density in the quasistatic case, short duration ( $\le 10$ ns) larger amplitude pulses ( $\simeq 10$ times the quasistatic threshold current) lead to only partial magnetization reversal and domain formation. We associate the partial reversal with the limited time for reversed domain expansion during the pulse.
Corporate ownership of the public debt: mapping the new aristocracy of finance

In various writings Karl Marx made references to an ‘aristocracy of finance’ in Western Europe and the USA that dominated ownership of the public debt. Drawing on original research, this article offers the first comprehensive analysis of public debt ownership within the US corporate sector. The research shows that over the past three decades, and especially in the context of the current crisis, a new aristocracy of finance has emerged, as holdings of the public debt have become rapidly concentrated in favour of large corporations classified within Finance, Insurance and Real Estate. Operationalizing Wolfgang Streeck's concept of the ‘debt state’, the article goes on to demonstrate how concentration in ownership of the public debt reinforces patterns of social inequality and proceeds in tandem with a shift in government policy, one that prioritizes the interests of government bondholders over the general citizenry.
In Search of Chemical Frustration in the Ca-Cu-Cd System: Chemical Pressure Relief in the Crystal Structures of ­Ca5Cu2Cd and Ca2Cu2Cd9

Structural complexity in intermetallic phases is increasingly being linked to the coexistence of or competition between mutually exclusive types of bonding or packing. We present an approach to inducing such competition through the choice of a ternary combination of elements with inherent incompatibilities in the bonding preferences of their binary subsystems, a conflict we term chemical frustration by analogy with magnetic phenomena. One system in which we perceived the potential for chemical frustration emerging is Ca-Cu-Cd. We describe our synthetic efforts in this system and the structures of two new compounds that we have obtained with the approximate compositions Ca5Cu2Cd and Ca2Cu2Cd9. Both compounds crystallize in ternary variants of binary structure types: the Cr5B3 type for Ca5Cu2Cd and the Mg2Zn11 type for Ca2Cu2Cd9. Despite their ternary compositions, the structural features of binary and even elemental phases can be discerned at the level of local coordination polyhedra. These observations can be rationalized by the position of the compounds in the phase diagram as a sort of phase-segregation at a very small length scale, consistent with the presence of incompatible bonding modes. The impetus for the formation of ternary phases, as opposed to a multiphase sample with macroscopic separation between binary and elemental phases, is traced through μ2-Huckel chemical pressure analysis to the relief of electronic packing frustration in hypothetical binary compounds upon introducing a third element.
Attitude Estimation Employing Common Frame Error Representations

This work studies vector representation in the attitude filtering problem. Because vector coordinates must be estimated in lieu of the abstract vector itself, the choice of representation is important. A challenge arises in attitude estimation when the coordinates of a vector are sought with respect to the attitude state coordinate frame. Although a wealth of research examines filtering with attitude state constraints or discontinuities, this work focuses on vector state estimation with respect to the attitude state frame. Specifically, an alternative vector state error is defined using common coordinates over all vector error realizations. A modified extended Kalman filter is developed with this error realization as its foundation. Numerical simulations are conducted, and results obtained using the new filter are compared with those generated by employing a standard estimate error definition.
Social Induction of Malleability in Ducklings

To test the hypothesis that social rearing may induce malleability, socially reared and socially isolated mallard duck, Anas platyrhynchos, embryos and hatchlings were exposed to the maternal call of a chicken, Gallus gallus domesticus, until 48h after hatching. The hatchlings were then tested with the chicken call versus the mallard maternal call at 48 and 65h. Social rearing before and after hatching led to the development of a persistent preference for the maternal call of the chicken. Social isolates did not develop a preference for the chicken call. The preference for the chicken call in the socially reared birds required both prenatal and postnatal exposure; socially reared birds exposed to the chicken call only before or only after hatching did not develop a preference for it. Social rearing overrode the usual canalizing influence of exposure to the embryo's contact call. Socially reared birds spend most of their time asleep, so there may be a reduction in contact calling and/or less exposure to visual stimulation (less intersensory competition). Malleability is the requisite first step in the behavioural pathway to evolution.
Recent Progress in Obtaining Semiconducting Single‐Walled Carbon Nanotubes for Transistor Applications

High purity semiconducting single-walled carbon nanotubes (s-SWCNTs) with a narrow diameter distribution are required for high-performance transistors. Achieving this goal is extremely challenging because the as-grown material contains mixtures of s-SWCNTs and metallic- (m-) SWCNTs with wide diameter distributions, typically inadequate for integrated circuits. Since 2000, numerous ex situ methods have been proposed to improve the purity of the s-SWCNTs. The majority of these techniques fail to maintain the quality and integrity of the s-SWCNTs with a few notable exceptions. Here, the progress in realizing high purity s-SWCNTs in as-grown and post-processed materials is highlighted. A comparison of transistor parameters (such as on/off ratio and field-effect mobility) obtained from test structures establishes the effectiveness of various methods and suggests opportunities for future improvements.
Generalized fuzzy c-means algorithms

This paper presents the development, testing and evaluation of generalized fuzzy c-means (FCM) algorithms. The proposed algorithms are developed by relaxing the constraints imposed on the membership functions by the axiomatic requirements associated with fuzzy c-partitions. Clustering is formulated as a constrained minimization problem, whose solution depends on the constraints imposed on the membership functions. This minimization problem results in a broad family of Generalized FCM algorithms, which include the FCM algorithm as a special case. The Minimum FCM and Geometric FCM algorithms are also obtained as limiting cases of Generalized FCM algorithms. The proposed formulation assigns to each feature vector a parameter that can be used to measure the certainty of its assignment to various clusters. These parameters can be used to identify outliers in the feature set. The Generalized FCM algorithms are evaluated and tested by experiments involving the IRIS data set and a two-dimensional vowel data set.
Reduction of photosynthetically active radiation under extreme stratospheric aerosol loads

The recently published hypothesis that the Cretaceous-Tertiary extinctions might be caused by an obstruction of sunlight is tested by model calculations. First we compute the total mass of stratospheric aerosols under normal atmospheric conditions for four different (measured) aerosol size distributions and vertical profiles. For comparison, the stratospheric dust masses after four volcanic eruptions are also evaluated. Detailed solar radiative transfer calculations are then performed for artificially increased aerosol amounts until the postulated darkness scenario is obtained. Thus we find that a total stratospheric aerosol mass between 1 and 4 times 10/sup 16/ g is sufficient to reduce photosynthesis to 10/sup 3/ of normal. We also infer from this result that the impact of a 0.4- to 3-km-diameter asteroid or a close encounter with a Halley-size comet may deposit that amount of particulates into the stratosphere. The darkness scenario of Alvarez et al., is thus shown to be a possible extinction mechanism, even with smaller size asteroids or comets than previously estimated.
Batch Codes Through Dense Graphs Without Short Cycles

Consider a large database of $n$ data items that need to be stored using $m$ servers. We study how to encode information so that a large number $k$ of read requests can be performed in parallel, while the rate remains constant (and ideally approaches one). This problem is equivalent to the design of multiset batch codes introduced by Ishai et al. We give the families of multiset batch codes with asymptotically optimal rates of the form $1-1/\text {poly}(k)$ and a number of servers $m$ scaling polynomially in the number of read requests $k$ . An advantage of our batch code constructions over most previously known multiset batch codes is explicit and deterministic decoding algorithms and asymptotically optimal fault tolerance. Our main technical innovation is a graph-theoretic method of designing multiset batch codes using dense bipartite graphs with no small cycles. We modify prior graph constructions of dense, high-girth graphs to obtain our batch code results. We achieve close-to-optimal tradeoffs between the parameters for bipartite graph-based batch codes.
Dyadic torsion of elliptic curves

Let k be a field of characteristic different from 2, and let \(\alpha _{1}, \alpha _{2}\), and \(\alpha _{3}\) be algebraically independent and transcendental over k. Let K be the transcendental field extension of k obtained by adjoining the elementary symmetric functions of \(\alpha _{i}\). Let E be the elliptic curve defined over K which is given by the equation \(y^{2} = (x - \alpha _{1})(x - \alpha _{2})(x - \alpha _{3})\). We define a tower of field extensions \(K = K_{0}' \subset K_{1}' \subset K_{2}' \subset \cdots \) by giving recursive formulas for the generators of each \(K_{n}'\) over \(K_{n - 1}'\). We show that \(K_{\infty }'\) is a certain subextension of the field \(K(E[2^{\infty }]) = \bigcup _{n = 0}^{\infty } K(E[2^{n}])\), and a generator of \(K(E[2^{\infty }])\) over \(K_{\infty }'(\mu _{2})\) is given. Moreover, if we assume that k contains all 2-power roots of unity, for each n, we show that \(K(E[2^{n}])\) contains \(K_{n}'\) and is contained in a certain quadratic extension of \(K_{n + 1}'\).
Learning Fast-Mixing Models for Structured Prediction

Markov Chain Monte Carlo (MCMC) algorithms are often used for approximate inference inside learning, but their slow mixing can be difficult to diagnose and the resulting approximate gradients can seriously degrade learning. To alleviate these issues, we define a new model family using strong Doeblin Markov chains, whose mixing times can be precisely controlled by a parameter. We also develop an algorithm to learn such models, which involves maximizing the data likelihood under the induced stationary distribution of these chains. We show empirical improvements on two inference tasks.
Learning to identify contrast-defined letters in peripheral vision

Performance for identifying luminance-defined letters in peripheral vision improves with training. The purpose of the present study was to examine whether performance for identifying contrast-defined letters also improves with training in peripheral vision, and whether any improvement transfers to luminance-defined letters. Eight observers were trained to identify contrast-defined letters presented singly at 10 degrees eccentricity in the inferior visual field. Before and after training, we measured observers' thresholds for identifying luminance-defined and contrast-defined letters, embedded within a field of white luminance noise (maximum luminance contrast=0, 0.25, and 0.5), at the same eccentric location. Each training session consisted of 10 blocks (100 trials per block) of identifying contrast-defined letters at a background noise contrast of 0.5. Letters (x-height=4.2 degrees) were the 26 lowercase letters of the Times-Roman alphabet. Luminance-defined letters were generated by introducing a luminance difference between the stimulus letter and its mid-gray background. The background noise covered both the letter and its background. Contrast-defined letters were generated by introducing a differential noise contrast between the group of pixels that made up the stimulus letter and the group of pixels that made up the background. Following training, observers showed a significant reduction in threshold for identifying contrast-defined letters (p<0.0001). Averaged across observers and background noise contrasts, the reduction was 25.8%, with the greatest reduction (32%) occurring at the trained background noise contrast. There was virtually no transfer of improvement to luminance-defined letters, or to an untrained letter size (2 x original), or an untrained retinal location (10 degrees superior field). In contrast, learning transferred completely to the untrained contralateral eye. Our results show that training improves performance for identifying contrast-defined letters in peripheral vision. This perceptual learning effect seems to be stimulus-specific, as it shows no transfer to the identification of luminance-defined letters. The complete interocular transfer, and the retinotopic (retinal location) and size specificity of the learning effect are consistent with the properties of neurons in early visual area V2.
Pet ownership, social support, and one-year survival after acute myocardial infarction in the Cardiac Arrhythmia Suppression Trial (CAST)

Social support and pet ownership, a nonhuman form of social support, have both been associated with increased coronary artery disease survival. The independent effects of pet ownership, social support, disease severity, and other psychosocial factors on 1-year survival after acute myocardial infarction are examined prospectively. The Cardiac Arrhythmia Suppression Trial provided physiologic data on a group of post-myocardial infarction patients with asymptomatic ventricular arrhythmias. An ancillary study provided psychosocial data, including pet ownership, social support, recent life events, future life events, anxiety, depression, coronary prone behavior, and expression of anger. Subjects (n = 424) were randomly selected from patients attending participating Cardiac Arrhythmia Suppression Trial sites and completed baseline psychosocial questionnaires. One year survival data were obtained from 369 patients (87%), of whom 112 (30.4%) owned pets and 20 (5.4%) died. Logistic regression indicates that high social support (p < 0.068) and owning a pet (p = 0.085) tend to predict survival independent of physiologic severity and demographic and other psychosocial factors. Dog owners (n = 87, 1 died) are significantly less likely to die within 1 year than those who did not own dogs (n = 282, 19 died; p < 0.05); amount of social support is also an independent predictor of survival (p = 0.065). Both pet ownership and social support are significant predictors of survival, independent of the effects of the other psychosocial factors and physiologic status. These data confirm and extend previous findings relating pet ownership and social support to survival among patients with coronary artery disease.
RANS Analyses of Turbofan Nozzles With Internal Wedge Deflectors for Noise Reduction

Computational fluid dynamics (CFD) was used to evaluate the flow field and thrust performance of a promising concept for reducing the noise at take-off of dual-stream turbofan nozzles. The concept, offset stream technology, reduces the jet noise observed on the ground by diverting (offsetting) a portion of the fan flow below the core flow, thickening and lengthening this layer between the high-velocity core flow and the ground observers. In this study a wedge placed in the internal fan stream is used as the diverter. Wind, a Reynolds averaged Navier-Stokes (RANS) code, was used to analyze the flow field of the exhaust plume and to calculate nozzle performance. Results showed that the wedge diverts all of the fan flow to the lower side of the nozzle, and the turbulent kinetic energy on the observer side of the nozzle is reduced. This reduction in turbulent kinetic energy should correspond to a reduction in noise. However, because all of the fan flow is diverted, the upper portion of the core flow is exposed to the freestream, and the turbulent kinetic energy on the upper side of the nozzle is increased, creating an unintended noise source. The blockage due to the wedge reduces the fan mass flow proportional to its blockage, and the overall thrust is consequently reduced. The CFD predictions are in very good agreement with experimental flow field data, demonstrating that RANS CFD can accurately predict the velocity and turbulent kinetic energy fields. While this initial design of a large scale wedge nozzle did not meet noise reduction or thrust goals, this study identified areas for improvement and demonstrated that RANS CFD can be used to improve the concept.
PHYSICAL PROPERTIES OF COMPLEX C HALO CLOUDS

Observations from the Galactic Arecibo L-band Feed Array H I (GALFA-H I) Survey of the tail of Complex C are presented and the halo clouds associated with this complex are cataloged. The properties of the Complex C clouds are compared to clouds cataloged at the tail of the Magellanic Stream to provide insight into the origin and destruction mechanism of Complex C. Magellanic Stream and Complex C clouds show similarities in their mass distributions (slope = –0.7 and –0.6 , respectively) and have a common line width of 20-30 km s–1 (indicative of a warm component), which may indicate a common origin and/or physical process breaking down the clouds. The clouds cataloged at the tail of Complex C extend over a mass range of 101.1-104.8 M ☉, sizes of 101.2-102.6 pc, and have a median volume density and pressure of 0.065 cm–3 and (P/k) = 580 K cm–3. We do not see a prominent two-phase structure in Complex C, possibly due to its low metallicity and inefficient cooling compared to other halo clouds. Assuming that the Complex C clouds are in pressure equilibrium with a hot halo medium, we find a median halo density of 5.8 × 10–4 cm–3, which given a constant distance of 10 kpc is at a z-height of ~3 kpc. Using the same argument for the Stream results in a median halo density of . These densities are consistent with previous observational constraints and cosmological simulations. We also assess the derived cloud and halo properties with three-dimensional grid simulations of halo H I clouds and find that the temperature is generally consistent within a factor of 1.5 and the volume densities, pressures, and halo densities are consistent within a factor of three.
A self-similar model for shear flows in dense granular materials

We propose a model to describe the quasistatic shearing of dry granular materials, which notably captures the differences in velocity profiles recently observed in 2 and 3D Couette flow experiments. In our scheme, the steady-state flow is due to the intermittent motion of clusters of particles moving together with the wall. The motion of a cluster is associated with the transient formation of a fracture inside the sheared pack. The model is based on the existence of a persistence length for the fractures, which imposes a self-similar structure on the clusters. Through a probabilistic approach, we can evaluate the rate of appearance of a cluster of a given size and obtain a prediction for the average velocity profiles. We also predict the existence of large stress fluctuations at the moving wall, whose characteristics are in good agreement with experimental data.
A comparison of satellite systems for gravity field measurements

A detailed and accurate earth gravity field model is important to the understanding of the structure and composition of the earth's crust and upper mantle. Various satellite-based techniques for providing more accurate models of the gravity field are analyzed and compared. A high-low configuration satellite-to-satellite tracking mission is recommended for the determination of both the long wavelength and short wavelength portions of the field. Satellite altimetry and satellite gradiometry missions are recommended for determination of the short wavelength portion of the field.
The hydrolysis of Di‐isopropyl methylphosphonate in ground water

Abstract The half‐life of di‐isopropyl methylphosphonate (DIMP) in ground water at 10°C was estimated to be 500 years with a 95% confidence interval of 447 to 559 years from measurements of the hydrolysis rates at four temperatures ranging between 70 and 98°C. First‐order kinetics were assumed, and the Arrhenius equation was used to extrapolate the hydrolysis rates to the normal temperature of ground water, 10°C. The half‐life calculated at this temperature for ASTM Type II water was estimated to be 684 years with a 95% confidence interval of 470 to 995 years, in agreement with a previously published study. The major hydrolysis products detected were isopropyl methylphosphonic acid and methylphosphonic acid. After heating samples for 43 days at 90°C, the molar accounting of the remaining DIMP and its detected hydrolysis products was 15% of the starting material. Inorganic phosphate was not detected. The very slow rate of DIMP hydrolysis in ground water suggests that the unidentified products are not likel...
Submodular Approximation: Sampling-based Algorithms and Lower Bounds

We introduce several generalizations of classical computer science problems obtained by replacing simpler objective functions with general submodular functions. The new problems include submodular load balancing, which generalizes load balancing or minimum-makespan scheduling, submodular sparsest cut and submodular balanced cut, which generalize their respective graph cut problems, as well as submodular function minimization with a cardinality lower bound. We establish upper and lower bounds for the approximability of these problems with a polynomial number of queries to a function-value oracle. The approximation guarantees that most of our algorithms achieve are of the order of $\sqrt{{n}/{\ln n}}$. We show that this is the inherent difficulty of the problems by proving matching lower bounds. We also give an improved lower bound for the problem of approximating a monotone submodular function everywhere. In addition, we present an algorithm for approximating submodular functions with a special structure, whose guarantee is close to the lower bound. Although quite restrictive, the class of functions with this structure includes the ones that are used for lower bounds both by us and in previous work.
Medical students' exposure to and attitudes about the pharmaceutical industry: a systematic review.

Background The relationship between health professionals and the pharmaceutical industry has become a source of controversy. Physicians' attitudes towards the industry can form early in their careers, but little is known about this key stage of development.
Memory and comprehension for health information among older adults: Distinguishing the effects of domain-general and domain-specific knowledge

While there is evidence that knowledge influences understanding of health information, less is known about the processing mechanisms underlying this effect and its impact on memory. We used the moving window paradigm to examine how older adults varying in domain-general crystallised ability (verbal ability) and health knowledge allocate attention to understand health and domain-general texts. Participants (n = 107, age: 60-88 years) read and recalled single sentences about hypertension and about non-health topics. Mixed-effects modelling of word-by-word reading times suggested that domain-general crystallised ability increased conceptual integration regardless of text domain, while health knowledge selectively increased resource allocation to conceptual integration at clause boundaries in health texts. These patterns of attentional allocation were related to subsequent recall performance. Although older adults with lower levels of crystallised ability were less likely to engage in integrative processing, when they did, this strategy had a compensatory effect in improving recall. These findings suggest that semantic integration during reading is an important comprehension process that supports the construction of the memory representation and is engendered by knowledge. Implications of the findings for theories of text processing and memory as well as for designing patient education materials are discussed.
Large deviations and linear statistics for potential theoretic ensembles associated with regular closed sets

A two-dimensional statistical model of N charged particles interacting via logarithmic repulsion in the presence of an oppositely charged regular closed region K whose charge density is determined by its equilibrium potential at an inverse temperature β is investigated. When the charge on the region, s, is greater than N, the particles accumulate in a neighborhood of the boundary of K, and form a point process in the complex plane. We describe the weak* limits of the joint intensities of this point process and show that it is exponentially likely to find the process in a neighborhood of the equilibrium measure for K.
Spectrum-Generating Algebra and No-Ghost Theorem for the Neveu-Schwarz Model

The no-ghost theorem of Brower for the conventional dual model (intercept ${\ensuremath{\alpha}}_{0}=1$) is extended to the Neveu-Schwarz model, and its spectrum-generating algebra is constructed. These conformally invariant generators (${A}_{n}, {B}_{s}$) are obtained by a systematic use of the gauges ${G}_{r}$. As a consequence it is demonstrated that particular dual models having resonances with positive-definite norms and masses are possible.
Response of the Antarctic Stratosphere to Two Types of El Niño Events

This study is the first to identify a robust El Nino/Southern Oscillation (ENSO) signal in the Antarctic stratosphere. El Nino events are classified as either conventional "cold tongue" events (positive SST anomalies in the Nino 3 region) or "warm pool" events (positive SST anomalies in the Nino 4 region). The ERA-40, NCEP and MERRA meteorological reanalyses are used to show that the Southern Hemisphere stratosphere responds differently to these two types of El Nino events. Consistent with previous studies, "cold tongue" events do not impact temperatures in the Antarctic stratosphere. During "warm pool" El Nino events, the poleward extension and increased strength of the South Pacific Convergence Zone (SPCZ) favor an enhancement of planetary wave activity during the SON season. On average, these conditions lead to higher polar stratospheric temperatures and a weakening of the Antarctic polar jet in November and December, as compared with neutral ENSO years. The phase of the quasi-biennial oscillation (QBO) modulates the stratospheric response to "warm pool" El Nino events: the strongest planetary wave driving events are coincident with the easterly phase of the QBO.
Superconductors as giant atoms predicted by the theory of hole superconductivity

Abstract The theory of hole superconductivity proposes that superconductivity originates in the fundamental electron–hole asymmetry of condensed matter and that it is an ‘undressing’ transition. Here we propose that a natural consequence of this theory is that superconductors behave as giant atoms. The model predicts that the charge distribution in superconductors is inhomogeneous, with higher concentration of negative charge near the surface. Some of this negative charge will spill out, giving rise to a negative electron layer right outside the surface of the superconductor, which should be experimentally detectable. Also superconductors should have a tendency to easily lose negative charge and become positively charged. Macroscopic spin currents are predicted to exist in superconducting bodies, giving rise to electric fields near the surface of multiply connected superconductors that should be experimentally detectable.
Cell migration in Drosophila optic lobe neurons is controlled by eyeless/Pax6

In the developing Drosophila optic lobe, eyeless, apterous and distal-less, three genes that encode transcription factors with important functions during development, are expressed in broad subsets of medulla neurons. Medulla cortex cells follow two patterns of cell movements to acquire their final position: first, neurons are arranged in columns below each neuroblast. Then, during pupation, they migrate laterally, intermingling with each other to reach their retinotopic position in the adult optic lobe. eyeless, which encodes a Pax6 transcription factor, is expressed early in progenitors and controls aspects of this cell migration. Its loss in medulla neurons leads to overgrowth and a failure of lateral migration during pupation. These defects in cell migration among medulla cortex cells can be rescued by removing DE-Cadherin. Thus, eyeless links neurogenesis and neuronal migration.
Asymmetric epoxidation, Michael addition, and triple cascade reaction using polymer-supported prolinol-based auxiliaries

Abstract The applicability of polymer-supported diphenylprolinol derivatives in directing either asymmetric epoxidation or Michael addition of suitable α,β-unsaturated substrates has been assessed. Epoxidation of cinnamaldehyde in the solid state give poorer yields and stereoselectivities than in the solution-phase systems. In contrast Michael additions of several aldehyde enolates to 2-nitro-1-arylalkenes gave results that approached or surpassed those in solution, and could be extended successfully to a three-component Michael/Michael/aldol cascade process. Comparisons of the results of pendant- versus crosslinked functionalized resins in these applications were revealing of the benefits and limitations of each, as were attempts to reuse the polymer-bound auxiliaries.
Regioselective C–H bond amination by aminoiodanes

A new approach for the direct amination of 2-phenylpyridine derivatives using a diphthalimide-iodane and copper triflate has been developed. A series of different 2-phenylpyridine derivatives were aminated with yields up to 88%. Mechanistic investigations indicate that the reaction proceeds via a copper-mediated single electron transfer.
SYNTHESES OF DIAZA-18-CROWN-6 LIGANDS CONTAINING TWO UNITS EACH OF 4-HYDROXYAZOBENZENE, BENZIMIDAZOLE, URACIL, ANTHRAQUINONE, OR FERROCENE GROUPS

Abstract : Six diaza-18-crown-6 ligands each containing two aromatic side arms with responsive functions were prepared. Diaza-18-crown-6 containing two 4-hydroxyazobenzene or two 4- hydroxy-4'-(dimethylamino)-azobenzene (3 or 4) substituents were prepared via a one-pot Mannich reaction. Diaza-1 8-crown-6 containing two berizimidazole (5), two uracil (6) or two 9,10-anthraquinone (7) substituents were prepared by treating the diazacrown with the appropriate chloromethyl-containing compound. Reductive amination using sodium triacetoxyborohydride, diaza-18-crown-6 and ferrocenecarboxaldehyde was used to prepare bisferrocene-substituted diaza-18-crown-6 (3). Interactions of compounds 3, 5, and 6 with Na(+), K(+), Ba(2+), Ag(+), and Cu(2+) were evaluated by a calorimetric titration technique at 25 deg C in methanol. All three ligands form more stable complexes with Ag(+) and Cu(2+) (5 forms a precipitate with Ag(+)) than with Na(+) and K(+). Ligand 5 also forms a highly stable complex with Ba(2+).
Thermal conductivity of rare-earth nickel borocarbides

Abstract YNi 2 B 2 C and LuNi 2 B 2 C are relatively high T c superconductors ( T c =15.6K and 16.6K, respectively) for quaternary intermetallic compounds. Recent neutron scattering experiments show anomalous phonon behavior below T c for both YNi 2 B 2 C and LuNi 2 B 2 C. Thermal conductivity measurements have been performed and indicate a strong enhancement below T c in the thermal conductivity of LuNi 2 B 2 C, and a weaker enhancement below T c for YNi 2 B 2 C which is similar to measurements previously reported by others for YNi 2 B 2 C.
Stability of Oscillatory Integral Asymptotics in Two Dimensions

The stability under phase perturbations of the decay rate of local scalar oscillatory integrals in two dimensions is analyzed. For a smooth phase S(x,y) and a smooth perturbation function f(x,y), the decay rate for phase S(x,y)+tf(x,y) is shown to be the same for all but finitely many t and given an explicit description. The decay rate of the generic S(x,y)+tf(x,y) is always at least as fast as that of S(x,y), and the “good” cases where it is the same as that of S(x,y) are explicitly described. Uniform stability of the decay rate is proven for S(x,y)+f(x,y) for small enough such good f(x,y), and the coefficient of the leading term of the asymptotics is shown to be Lipschitz of some order alpha, again for small enough good perturbations f(x,y).
Impact of Customer Traffic and Service Process Outsourcing Levels on e‐Retailer Operational Performance

Many service firms deliver services via a mix of internally developed and delivered (i.e., insourced) and externally developed and delivered (i.e., outsourced) service processes. Service process outsourcing is especially common in e-retailing. Portions of e-retail customer ordering processes and delivery processes can be digitized and contracted to third-party vendors. Via outsourcing, service systems change from dyadic to triadic. Prior research examines consumer perceptions of dyadic (consumer to e-retailer) outcomes, but little research considers service co-delivery with outsourcing partners (i.e., triadic systems). Literature also does not focus on joint associations of service process outsourcing and customer traffic with e-retailer operations. We analyze several years of data on North American e-retailers. We first examine factors associated with e-retailer outsourcing levels, for front-end and back-end service processes. We observe customer traffic is positively associated with future outsourcing. We then examine how outsourcing moderates associations between contemporaneous customer traffic and e-retailer operational performance, as measured by numbers of processed orders, website response times, and customer satisfaction. Results suggest outsourcing levels are associated with operational outcomes, yet surprisingly, high outsourcing and high traffic jointly may not benefit e-retailers
A Hierarchy of Aryloxide Deprotection by Boron Tribromide

Aryl propargyl ethers and esters are cleaved selectively in the presence of aryl methyl ethers and esters by boron tribromide in dichloromethane. Under the same conditions, allyl ethers undergo very rapid Claisen rearrangement, and benzyl ethers are also cleaved more rapidly than propargyl. A mechanism involving intramolecular delivery of bromide to the propargyl terminus is proposed. [reaction: see text]
Chandra observations of supernova remnants and neutron stars – an overview

We present a brief overview of Chandra observations of supernova remnants and neutron stars, with emphasis on neutron stars in supernova remnants. The Chandra images demonstrate the importance of angular resolution in separating the neutron star emission from the surrounding nebulosity.
Attack-resilient time synchronization for wireless sensor networks

Abstract The existing time synchronization schemes in sensor networks were not designed with security in mind, thus leaving them vulnerable to security attacks. In this paper, we first identify various attacks that are effective to several representative time synchronization schemes, and then focus on a specific type of attack called delay attack , which cannot be addressed by cryptographic techniques. Next we propose two approaches to detect and accommodate the delay attack. Our first approach uses the generalized extreme studentized deviate (GESD) algorithm to detect multiple outliers introduced by the compromised nodes; our second approach uses a threshold derived using a time transformation technique to filter out the outliers. Finally we show the effectiveness of these two schemes through extensive simulations.
Re-examination of electroweak symmetry breaking in supersymmetry and implications for light superpartners

Abstract We examine arguments that could avoid light superpartners as an implication of supersymmetric radiative electroweak symmetry breaking. We argue that, from the point of view of string theory and standard approaches to generating the μ term, cancellations among parameters are not a generic feature. While the coefficients relating M Z to parameters in the soft supersymmetry breaking Lagrangian can be made smaller, these same mechanisms lead to lighter superpartner masses at the electroweak scale. Consequently we strengthen the implication that gluinos, neutralinos, and charginos are light and likely to be produced at the Fermilab Tevatron and a linear collider.
Aerobraking as a potential planetary capture mode.

The synthesis of manned aerobraking spacecraft for missions to Mars and Venus is described. Pertinent data derived from performance, weights, heating, and heat shield design analyses conducted to support the synthesis are presented. The sequential approach that was used, in which aerobraker mission-system requirements were establised and candidate vehicle arrangements were prepared, is discussed. Sensitivity analyses and selected configurations are presented along with the evolved modular approach to aerobraker spacecraft design. Considerable commonality between the Mars and Venus vehicles and requirements for elliptical parking orbit missions using modular designs is shown. Comparisons of the aerobraking and retrobraking modes of orbital capture at Mars and Venus are presented to show that a chemically (FLOX/CELi) propelled aerobraker vehicle system requires less mass on Earth orbit than a nuclear (LH^) retrobraker for all mission opportunities from 1980 to 2000.
The N/O Plateau of Blue Compact Galaxies: Monte Carlo Simulations of the Observed Scatter

Chemical evolution models and Monte Carlo simulation techniques have been combined for the first time to study the distribution of blue compact galaxies on the N/O plateau. Each simulation comprises 70 individual chemical evolution models. For each model, input parameters relating to a galaxy's star formation history (bursting or continuous star formation, star formation efficiency), galaxy age, and outflow rate are chosen randomly from ranges predetermined to be relevant. Predicted abundance ratios from each simulation are collectively overplotted onto the data to test its viability. We present our results both with and without observational scatter applied to the model points. Our study shows that most trial combinations of input parameters, including a simulation comprising only simple models with instantaneous recycling, are successful in reproducing the observed morphology of the N/O plateau once observational scatter is added. Therefore, simulations that include delay of nitrogen injection are no longer favored over those that propose that most nitrogen is produced by massive stars, if only the plateau morphology is used as the principal constraint. The one scenario that clearly cannot explain plateau morphology is one in which galaxy ages are allowed to range below 250 Myr. We conclude that the present data for the N/O plateau are insufficient by themselves for identifying the portion of the stellar mass spectrum most responsible for cosmic nitrogen production.
Command Generation for Three-Axis CNC Machining

This paper investigates the command generation for three-axis CNC machining. In the integration of CAD and CAM, it is necessary to relate machine tool dynamics and control in a CAM process to the geometrical data in a CAD model. The data stored in a CAD model is usually static in nature and represented by unitless parameters. Yet, in machine tool motion and control, the data should be transformed into a time dependent domain. In this paper, the geometrical properties of a cutter path, including position, tangent, curvature and torsion are analytically related to the motion dynamics of a machine tool including feedrate, acceleration, jerk and driving force. The information about feedrate, acceleration and driving force is needed for command generation. Jerk analysis can be used for cutting quality analysis.
Lateral inhibition models of developmental processes

Abstract Most mathematical models for embryological pattern formation depend on the phenomenon of local autocatalysis with lateral inhibition (LALI). While the underlying physical and chemical mechanisms hypothesized by the models may be quite different, they all predict very similar kinds of spatial patterns. Therefore, since the underlying mechanism cannot in general be deduced from the pattern itself, other criteria must be applied in evaluating the usefulness of pattern formation models. The author points out how LALI is implemented in neural, chemical, and mechanical models of development, and suggests some general properties of LALI models that may impose limitations on organ shapes in ontogeny and phylogeny.