cssi/SciSciGPT-SciSciNet huggingface dataset:
Parallelizing user-defined and implicit reductions globally on multiprocessors

Multiprocessors are becoming prevalent in the PC world. Major CPU vendors such as Intel and Advanced Micro Devices have migrated to multicore processors. However, this also means that computers will run an application at full speed only if that application is parallelized. To take advantage of more than a fraction of compute resource on a die, we develop a compiler to parallelize a common and powerful programming paradigm, namely reduction. Our goal is to exploit the full potential of reductions for efficient execution of applications on multiprocessors, including multicores. Note that reduction operations are common in streaming applications, financial computing and HPC domain. In fact, 9% of all MPI invocations in the NAS Parallel Benchmarks are reduction library calls. Recognizing implicit reductions in Fortran and C is important for parallelization on multiprocessors. Recent languages such as Brook Streaming language and Chapel language allow users to specify reduction functions. Our compiler provides a unified framework for processing both implicit and user-defined reductions. Both types of reductions are propagated and analyzed interprocedurally. Our global algorithm can enhance the scope of user-defined reductions and parallelize coarser-grained reductions. Thanking to the powerful algorithm and representation, we obtain an average speedup of 3 on 4 processors. The speedup is only 1.7 if only intraprocedural scalar reductions are parallelized.
Monitoring Continual Range Queries

This paper provides an overview of a query indexing method, called VCR indexing, for monitoring continual range queries. A VCR-based query index enables fast matching of events against a large number of range predicates. We first describe VCR indexing for general event matching against a set of 2D range predicates. We then show how VCR indexing can be used for efficient processing of continual range queries over moving objects. VCR stands for virtual construct rectangle. A set of VCRs are predefined, each with a unique ID. Each region defined by the range predicate is decomposed into or covered by one or more activated VCRs. The predicate ID is then stored in the ID lists associated with these activated VCRs. The use of VCRs provides an indirect and cost-effective way of pre-computing the search result for any given event or object position. Event matching becomes very efficient.
Rhodium(I)‐Catalyzed [2+2+2+2] Cycloaddition of Diynes To Form Cyclooctatetraenes

Unique reactivity of a rhodium catalyst in the presence of many different Lewis basic additives was observed and studied. In the absence of additives, it was observed that a selective [2+2+2] reaction to form benzene products occurred; however, in the presence of an additive, optimally DMSO, the first rhodium(I)-catalyzed [2+2+2+2] reaction of alkynes occurred. A screen of different additives and catalysts was performed. Finally, a brief mechanistic study per-formed by using a ReactIR determined that DMSO coordinates to the catalyst, which affects the energetics of the reaction pathway. This appears primarily to raise the transition-state energy for the reductive elimination to form the benzene products.
Solar-Type Post-T Tauri Stars in the Nearest OB Subgroups

I discuss results from the recent spectroscopic survey for solar-type pre-MS stars in the Lower Centaurus-Crux (LCC) and Upper Centaurus-Lupus (UCL) OB subgroups by Mamajek, Meyer, & Liebert (2002, AJ, 124, 1670). LCC and UCL are subgroups of the Sco-Cen OB association, and the two nearest OB subgroups to the Sun. In the entire survey of 110 pre-main sequence stars, there exists only one Classical T Tauri star (PDS 66), implying that only ∼1% of ∼1 M⊙ stars are still accreting at age 13±7 (1σ) Myr. Accounting for observational errors, the HRD placement of the pre-MS stars is consistent with the bulk of star-formation taking place within 5–10 Myr. In this contribution, I estimate conservative upper limits to the intrinsic velocity dispersions of the post-T Tauri stars in the LCC and UCL subgroups (<1.6 km s−1 and <2.2 km s−1, respectively; 95% CL) using Monte Carlo simulations of Tycho-2 proper motions for candidate subgroup members. I also demonstrate that a new OB subgroup recently proposed to exist in Chamaeleon probably does not.
Revisiting epistemic specifications

In 1991, Michael Gelfond introduced the language of epistemic specifications. The goal was to develop tools for modeling problems that require some form of meta-reasoning, that is, reasoning over multiple possible worlds. Despite their relevance to knowledge representation, epistemic specifications have received relatively little attention so far. In this paper, we revisit the formalism of epistemic specification. We offer a new definition of the formalism, propose several semantics (one of which, under syntactic restrictions we assume, turns out to be equivalent to the original semantics by Gelfond), derive some complexity results and, finally, show the effectiveness of the formalism for modeling problems requiring meta-reasoning considered recently by Faber and Woltran. All these results show that epistemic specifications deserve much more attention that has been afforded to them so far.
Cepheid Limb Darkening Models for the VLTI

We present a new method to compute wavelength- and phase-dependent limb darkening corrections for classical Cepheids. These corrections are derived from hydrodynamic simulations and radiative transfer modeling with a full set of atomic and molecular opacities. Comparison with hydrostatic models having the same stellar parameters show a larger limb darkening for most phases in our models, and temporal variations related to the hydrodynamics of the stellar pulsation. We assess the implications of our results with respect to the geometric Baade-Wesselink method, which uses interferometric measurements of Cepheid angular diameters to determine their distances and radii. The relevance of the hydrodynamic effects predicted by our model on the limb darkening of pulsating Cepheids is finally discussed in terms of the predicted capabilities of the VLTI.
Metal–Metal Bonding in Bridging Hydride and Alkyl Compounds

A theoretical analysis of the bonding in a series of dinuclear compounds that feature bridging hydride or alkyl ligands indicates that the direct metal–metal bond order is best predicted by an electron-counting procedure in which 3-center-2-electron M–H–M and M–R–M interactions are represented by the μ-LX “half-arrow” method. In contrast, an electron-counting procedure which apportions half of the valence electron of H or R to each metal center results in direct metal–metal bond orders that are not in accord with theory.
The Planet Observer's Handbook

This is an informative, up-to-date and well-illustrated guide to planetary observations for amateurs. After a brief description of the solar system and a chapter on the celestial sphere, readers are shown how to choose, test and use a telescope with various accessories and how to make observations and record results. For each planet and the asteroids, details are given of observational techniques, together with suggestions for how to make contributions of scientific value. From a general description and detailed observational history of each planet, observers can anticipate what they should see and assess their own observations. The chapter on planetary photography includes the revolutionary use of videography, charge coupled devices and video-assisted drawing. There are also chapters on making maps and planispheres and on photoelectric photometry.
On the Gauge Theory/Geometry Correspondence

The 't Hooft expansion of SU(N) Chern-Simons theory on $S^3$ is proposed to be exactly dual to the topological closed string theory on the $S^2$ blow up of the conifold geometry. The $B$-field on the $S^2$ has magnitude $Ng_s=\lambda$, the 't Hooft coupling. We are able to make a number of checks, such as finding exact agreement at the level of the partition function computed on {\it both} sides for arbitrary $\lambda$ and to all orders in 1/N. Moreover, it seems possible to derive this correspondence from a linear sigma model description of the conifold. We propose a picture whereby a perturbative D-brane description, in terms of holes in the closed string worldsheet, arises automatically from the coexistence of two phases in the underlying U(1) gauge theory. This approach holds promise for a derivation of the AdS/CFT correspondence.
Strings in Gravity with Torsion

A theory of gravitation in 4D is presented with strings used in the material action in U 4 spacetime. It is shown that the string naturally gives rise to torsion. It is also shown that the equation of motion a string follows from the Bianchi identity, gives the identical result as the Noether conservation laws, and follows a geodesic only in the lowest order approximation. In addition, the conservation laws show that strings naturally have spin, which arises not from their motion but from their one dimensional structure.
Quantum circuits for incompletely specified two-qubit operators

While the question "how many CNOT gates are needed to simulate an arbitrary twoqubit operator" has been conclusively answered - three are necessary and sufficient - previous work on this topic assumes that one wants to simulate a given unitary operator up to global phase. However, in many practical cases additional degrees of freedom are allowed. For example, if the computation is to be followed by a given projective measurement, many dissimilar operators achieve the same output distributions on all input states. Alternatively, if it is known that the input state is |0〉, the action of the given operator on all orthogonal states is immaterial. In such cases, we say that the unitary operator is incompletely specified; in this work, we take up the practical challenge of satisfying a given specification with the smallest possible circuit. In particular, we identify cases in which such operators can be implemented using fewer quantum gates than are required for generic completely specified operators.
Two-phase flows and heat transfer within systems with ambient pressure above the thermodynamic critical pressure

In systems where the design inlet and outlet pressures P sub amb are maintained above the thermodynamic critical pressure P sub c, it is often assumed that heat and mass transfer are governed by single-phase relations and that two-phase flows cannot occur. This simple rule of thumb is adequate in many low-power designs but is inadequate for high-performance turbomachines, boilers, and other systems where two-phase regions can exist even though P sub amb P sub c. Heat and mass transfer and rotordynamic-fluid-mechanic restoring forces depend on momentum differences, and those for a two-phase zone can differ significantly from those for a single-phase zone. By using a laminar, variable-property bearing code and a rotating boiler code, pressure and temperature surfaces were determined that illustrate nesting of a two-phase region within a supercritical pressure region. The method of corresponding states is applied to bearings with reasonable rapport.
Performance of a range-ambiguous MTI and doppler filter system

In this report the clutter rejection performance of a range-ambiguous MTI and doppler filter system is analyzed. The reduction of correlation time in a range-ambiguous system in general improves the clutter rejection performance. However, due to the fold-over phenomenon, a far-away target has to compete with the near-in clutter; hence, a higher improvement factor is required. Examples presented here which take into account these effects show that the improvement factor of a range-ambiguous MTI system is slightly better than that of a range-unambiguous system. However, the performance of a doppler filter processor in a range-ambiguous system is worse.
Evidence of multiple r-process sites in the early galaxy: new observations of cs 22892-052

First results are reported of a new abundance study of neutron-capture elements in the ultra-metal-poor ([Fe/H] = -3.1) halo field giant star CS 22892-052. Using new high-resolution, high signal-to-noise ratio spectra, abundances of more than 30 neutron-capture elements (Z > 30) have been determined. Six elements in the 40 < Z < 56 domain (Nb, Ru, Rh, Pd, Ag, and Cd) have been detected for the first time in an ultra-metal-poor star. Abundances are also derived for three of the heaviest stable elements (Os, Ir, and Pb). A second transition of thorium, Th II λ4086, confirms the abundance deduced from the standard Th II λ4019 line, and an upper limit to the abundance of uranium is established from the absence of the U II λ3859 line. As found in previous studies, the abundances of the heavier (Z ≥ 56) stable neutron-capture elements in CS 22892-052 match well the scaled solar system r-process abundance distribution. From the observed Th abundance, an average age of 16 ± 4 Gyr is derived for CS 22892-052, consistent with the lower age limit of 11 Gyr derived from the upper limit on the U abundance. The concordance of scaled solar r-process and CS 22892-052 abundances breaks down for the lighter neutron-capture elements, supporting previous suggestions that different r-process production sites are responsible for lighter and heavier neutron-capture elements.
Improving Precision of Java Script Program Analysis with an Extended Domain of Intervals

Interpretation has been a promising approach for static analysis of Java Script programs. Static analysis is used for security auditing, debugging, optimization and error checking. Java Script is dynamically typed, uses prototype-based inheritance and first class functions. It supports reflective calls, access to object fields and allows object fields to be dynamically added and deleted. These dynamic features make Java Script flexible to use. At the same time, they make Java Script applications more susceptible to programming errors. The challenge that comes with the analysis of such programs is the design of abstract domains that will precisely track properties of interest without affecting performance. This paper presents our work on improving analysis precision of Java Script programs. We used an extended domain of intervals to track ranges of numeric values of variables. This is the first time interval domain has been applied to the analysis of the full Java Script language. We implemented the new abstract domain within a Java Script abstract interpreter. Our experiments show that the new abstract domain enables the abstract interpreter to infer more precise type information for most of the benchmark programs and strikes a good balance between analysis precision and cost. While the analysis of some benchmarks take more time as expected, some other benchmarks actually take less time.
MHD Turbulence: Scaling Laws and Astrophysical Implications

Turbulence is the most common state of astrophysical flows. In typical astrophysical fluids, turbulence is accompanied by strong magnetic fields, which has a large impact on the dynamics of the turbulent cascade. Recently, there has been a significant breakthrough on the theory of magnetohydrodynamic (MHD) turbulence. For the first time we have a scaling model that is supported by both observations and numerical simulations. We review recent progress in studies of both incompressible and compressible turbulence. We compare Iroshnikov-Kraichnan and Goldreich-Sridhar models, and discuss scalings of Alfven, slow, and fast waves. We also discuss the completely new regime of MHD turbulence that happens below the scale at which hydrodynamic turbulent motions are damped by viscosity. In the case of the partially ionized diffuse interstellar gas the viscosity is due to neutrals and truncates the turbulent cascade at ~parsec scales. We show that below this scale magnetic fluctuations with a shallow spectrum persist and discuss the possibility of a resumption of the MHD cascade after ions and neutrals decouple. We discuss the implications of this new insight into MHD turbulence for cosmic ray transport, grain dynamics, etc., and how to test theoretical predictions against observations.
The Formulation of Quantum Field Theory in Curved Spacetime

The usual formulations of quantum field theory in Minkowski spacetime make crucial use of Poincare symmetry, positivity of total energy, and the existence of a unique, Poincare invariant vacuum state. These and other key features of quantum field theory do not generalize straightforwardly to curved spacetime. We discuss the conceptual obstacles to formulating quantum field theory in curved spacetime and how they can be overcome.
The Real Density Matrix

We introduce a nonsymmetric real matrix which contains all the information that the usual Hermitian density matrix does, and which has exactly the same tensor product structure. The properties of this matrix are analyzed in detail in the case of multi-qubit (e.g., spin = 1/2) systems, where the transformation between the real and Hermitian density matrices is given explicitly as an operator sum, and used to convert the essential equations of the density matrix formalism into the real domain. PACS: 03.65.Ca; 03.67-a; 33.25.+k; 02.10.Xm
Point: should childhood vaccination against measles be a mandatory requirement for attending school? Yes.

A measles outbreak linked to California’s Disneyland has led to > 300 cases in at least seven states, Mexico, and Canada through March 2015. Most cases occurred in people choosing to forego vaccination.1,2 The costs associated with this outbreak exceed those borne by individuals opting out of vaccination: > 10% of the California cases occurred in children too young to be vaccinated, schools and daycares were forced either to close or to enforce policies excluding unvaccinated and vulnerable children for multiple weeks, and health departments spent scores of personnel hours—and hundreds of thousands of dollars from limited budgets—containing the spread of this vaccine-preventable illness.1,2
Governing for impact and performance within social entrepreneurial ventures : the mediating role of organizational capabilities

Social entrepreneurial ventures pursue a double bottom line, i.e., they try to achieve simultaneous social and financial performance. Governance has been shown to be a critical issue for firm performance. However, this issue has been neglected in the SE literature. This exploratory study empirically addresses this gap by proposing a mediational model between governance behaviors (agency and stewardship) and financial performance and social impact. Although showing mixed results about the mediation by organizational capabilities, this study shows that these are good predictors of both financial performance and social impact, and that agents’ opportunistic behaviors negatively influence the development of these organizational capabilities.
Coping with urban fiscal stress around the world

The economic recession, the end of stimulus funding and central government cutbacks, rising social costs and aging, and the need for infrastructure upgrading for urbanization are putting enormous fiscal stress on cities. The financing capacity of municipalities is greatly affected because of the decline in the tax base, expenditure pressures, and growing and more expensive debt. Today's urban fiscal crisis is similar to that experienced in the 1970s, but the growing urbanization in the world and massive increase in municipal access to financial markets create a new context. This paper surveys three important topics related to the urban fiscal crisis in developed and developing countries: How do cities finance themselves? When they have access to financial markets, should city managers use loans, own revenues or private-public partnerships to pay for municipal expenditures? And what are the remedies to municipal fiscal crises in case of insolvency?
North American winter‐spring storms: Modeling investigation on tropical Pacific sea surface temperature impacts

[1] An increased frequency and intensity of winter and spring storms have recently manifested over a broad area of North America—along the east coast of the U.S. especially, though global mean storm tracks are suggested to shift northward. To understand these changes, we have conducted atmospheric model experiments, examining the response of North American storm activity to the elevated tropical Pacific sea surface temperature (SST) associated with El Nino. The results indicate that, when tropical Pacific SST increases, there are more numerous intense storms over southwestern, southeastern, and northwestern North America, but fewer weaker storms over the northeast. Transient eddy analysis of the general circulation demonstrates consistent changes, suggesting systematic changes from large-scale general circulation to synoptic-scale storms. These changes can be attributed to enhanced lower tropospheric baroclinicity, to which the southward shift and an intensification of extratropical jet streams make a major contribution.
Generators for the representation rings of certain wreath products

Abstract Working in the setting of Deligne categories, we generalize a result of Marin that hooks generate the representation ring of symmetric groups to wreath products of symmetric groups with a fixed finite group or Hopf algebra. In particular, when we take the finite group to be cyclic order 2 we recover a conjecture of Marin about Coxeter groups in type B.
The digital public library of america ingestion ecosystem: lessons learned after one year of large-scale collaborative metadata aggregation

The Digital Public Library of America (DPLA) aggregates metadata for cultural heritage materials from 20 direct partners, or Hubs, across the United States. While the initial build-out of the DPLA's infrastructure used a lightweight ingestion system that was ultimately pushed into production, a year's experience has allowed DPLA and its partners to identify limitations to that system, the quality and scalability of metadata remediation and enhancement possible, and areas for collaboration and leadership across the partnership. Although improved infrastructure is needed to support aggregation at this scale and complexity, ultimately DPLA needs to balance responsibilities across the partnership and establish a strong community that shares ownership of the aggregation process.
The Neuroscience of Consumer Decision-Making

While there is an extensive history of neuroscience, only recently has the theory and the methods of this discipline been applied to answer questions about decision making, choice, preference, risk and happiness. This new area of research, coined neuroeconomics, seeks to reveal more about the neural functioning and associated implications for economic and consumer behavior. In this paper are some of the key developments in neuroeconomics research as they relate to consumer decision-making, culminating with a discussion of possible future research areas in marketing where this type of research could be applied with important managerial, policy and academic implications.
Vacuum Cleaning CTL Formulae

Vacuity detection in model checking looks for properties that hold in a model, and can be strengthened without causing them to fail. Such properties often signal problems in the model, its environment, or the properties themselves. The seminal paper of Beer et al. [1] proposed an efficient algorithm applicable to a restricted set of properties. Subsequently, Kupferman and Vardi [15] extended vacuity detection to more expressive specification mechanisms. They advocated a more minute examination of temporal logic formulae than the one adopted in [1]. However, they did not address the issues of practicality and usefulness of this more scrupulous inspection. In this paper we discuss efficient algorithms for the detection of vacuous passes of temporal logic formulae, showing that a thorough vacuity check for CTL formulae can be carried out with very small overhead, and even, occasionally, in less time than plain model checking. We also demonstrate the usefulness of such a careful analysis with the help of case studies.
The emerging genomics and systems biology research lead to systems genomics studies

Synergistically integrating multi-layer genomic data at systems level not only can lead to deeper insights into the molecular mechanisms related to disease initiation and progression, but also can guide pathway-based biomarker and drug target identification. With the advent of high-throughput next-generation sequencing technologies, sequencing both DNA and RNA has generated multi-layer genomic data that can provide DNA polymorphism, non-coding RNA, messenger RNA, gene expression, isoform and alternative splicing information. Systems biology on the other hand studies complex biological systems, particularly systematic study of complex molecular interactions within specific cells or organisms. Genomics and molecular systems biology can be merged into the study of genomic profiles and implicated biological functions at cellular or organism level. The prospectively emerging field can be referred to as systems genomics or genomic systems biology. The Mid-South Bioinformatics Centre (MBC) and Joint Bioinformatics Ph.D. Program of University of Arkansas at Little Rock and University of Arkansas for Medical Sciences are particularly interested in promoting education and research advancement in this prospectively emerging field. Based on past investigations and research outcomes, MBC is further utilizing differential gene and isoform/exon expression from RNA-seq and co-regulation from the ChiP-seq specific for different phenotypes in combination with protein-protein interactions, and protein-DNA interactions to construct high-level gene networks for an integrative genome-phoneme investigation at systems biology level.
Microstructural study of synthetic sintered diamond and comparison with carbonado, a natural polycrystalline diamond

Efforts to simulate the extreme toughness of the polycrystalline diamond variety known as carbonado typically entail the sintering of diamond powders in the presence of metal solvent-catalysts. In this study, we have attempted to duplicate the carbonado microstructure by sintering diamond powders without catalysts in a multi-anvil press at pressures of 6 to 9 GPa, temperatures of 1200 to 1800 °C, and times up to 6 h. The resultant microstructural defect assemblages for each experimental condition were characterized by transmission electron microscopy (TEM). Despite the absence of catalysts, sintered compacts were successfully produced for all runs, though intergranular porosity was significantly higher than that observed in natural carbonado. Primary grain sizes were reduced by more than 50% from their original dimensions in some experiments due to surface fracturing and abrasion, and aperiodic slip planes rigorously parallel to {111} consistently emerged in high densities, with lamellar spacings of 3 to 30 nm. In addition, sintering over all conditions produced polysynthetic spinel twinning in close association with the partial slip defects. Compacts compressed at 8 GPa produced some euhedral crystals with very low dislocation densities surrounded by grains in which dislocation densities were quite high. In addition, curviplanar defects loosely constrained to {111} were visible within some specimens sintered at the highest pressures. These textures resembled the polygonalization fabrics and defect microstructures observed in natural carbonado (De et al. 1998), and the appearance of these features suggests that our experiments at their most extreme pressure and temperature parameters reproduced carbonado-like defect assemblages. The formation of such textures in quasi-hydrostatic experiments suggests that shock metamorphism is not required to produce the periodic defect lamellae observed in carbonado.
Sum capacity of the Gaussian interference channel in the low interference regime

New upper bounds on the sum capacity of the two-user Gaussian interference channel are derived. Using these bounds, it is shown that treating interference as noise achieves the sum capacity if the interference levels are below certain thresholds.
On 2-Generator Subgroups of SO(3)

We classify all subgroups of SO(3) that are generated by two elements, each a rotation of finite order, about axes separated by an angle that is a rational multiple of 7r. In all cases we give a presentation of the subgroup. In most cases the subgroup is the free product, or the amalgamated free product, of cyclic groups or dihedral groups. The relations between the generators are all simple consequences of standard facts about rotations by 7r and 7r/2. Embedded in the subgroups are explicit free groups on 2 generators, as used in the Banach-Tarski paradox.
Cylindrical hierarchy for deforming necklaces

Recently, Guibas et al. [7] studied deformable necklaces - flexible chains of balls, called beads, in which only adjacent balls can intersect. In this paper, we investigate a problem of covering a necklace by cylinders. We consider several problems under different optimization criteria. We show that optimal cylindrical cover of a necklace with n beads in R3 by k cylinders can be computed in polynomial time. We also study a bounding volume hierarchy based on cylinders.
Global Civil Unrest: Contagion, Self-Organization, and Prediction

Civil unrest is a powerful form of collective human dynamics, which has led to major transitions of societies in modern history. The study of collective human dynamics, including collective aggression, has been the focus of much discussion in the context of modeling and identification of universal patterns of behavior. In contrast, the possibility that civil unrest activities, across countries and over long time periods, are governed by universal mechanisms has not been explored. Here, records of civil unrest of 170 countries during the period 1919–2008 are analyzed. It is demonstrated that the distributions of the number of unrest events per year are robustly reproduced by a nonlinear, spatially extended dynamical model, which reflects the spread of civil disorder between geographic regions connected through social and communication networks. The results also expose the similarity between global social instability and the dynamics of natural hazards and epidemics.
Far-from-equilibrium dynamics of a strongly coupled non-Abelian plasma with non-zero charge density or external magnetic field

Using holography, we study the evolution of a spatially homogeneous, far from equilibrium, strongly coupled $$ \mathcal{N}=4 $$ supersymmetric Yang-Mills plasma with a non-zero charge density or a background magnetic field. This gauge theory problem corresponds, in the dual gravity description, to an initial value problem in Einstein-Maxwell theory with homogeneous but anisotropic initial conditions. We explore the dependence of the equilibration process on different aspects of the initial departure from equilibrium and, while controlling for these dependencies, examine how the equilibration dynamics are affected by the presence of a non-vanishing charge density or an external magnetic field. The equilibration dynamics are remarkably insensitive to the addition of even large chemical potentials or magnetic fields; the equilibration time is set primarily by the form of the initial departure from equilibrium. For initial deviations from equilibrium which are well localized in scale, we formulate a simple model for equilibration times which agrees quite well with our results.
Downstream coarsening in headwater channels

[1] Field data from four mountain drainage basins in western Washington document systematic downstream coarsening of median bed surface grain size (D50) and a subsequent shift to downstream fining at a drainage area of about 10 km2. Analyses of network-wide patterns of unit stream power derived from both channel surveys and digital elevation models reveal maximum unit stream power that in all four study areas roughly corresponds with both the grain size maxima and an inflection in the drainage area-slope relation thought to represent the transition from debris flow-dominated channels to fluvially dominated channels. Our results support the hypothesis that basin-wide trends in D50 are hydraulically controlled by systematic variations in unit stream power in addition to lag deposits forced by mass-wasting processes. The similar relations found in our four study areas suggest that the tendency for downstream coarsening may be ubiquitous in headwater reaches of mountain drainage basins where debris flow processes set the channel gradient.
A scaling limit for the degree distribution in sublinear preferential attachment schemes

We consider a general class of preferential attachment schemes evolving by a reinforcement rule with respect to certain sublinear weights. In these schemes, which grow a random network, the sequence of degree distributions is an object of interest which sheds light on the evolving structures. In this article, we use a fluid limit approach to prove a functional law of large numbers for the degree structure in this class, starting from a variety of initial conditions. The method appears robust and applies in particular to ‘non-tree’ evolutions where cycles may develop in the network. A main part of the argument is to show that there is a unique nonnegative solution to an infinite system of coupled ODEs, corresponding to a rate formulation of the law of large numbers limit, through C0-semigroup/dynamical systems methods. These results also resolve a question in Chung, Handjani and Jungreis (2003). © 2015 Wiley Periodicals, Inc. Random Struct. Alg., 2015
Dividends Versus Share Repurchase

In the past four decades, major U.S. corporations have increasingly repurchased significant amounts of their own common shares. The reasons for this development and its implications for the theory of share valuation and for public policy, however, have been subject to numerous, and often conflicting interpretations.
Electrocardiograms transmitted via facsimile may not allow accurate interval interpretation.

Background: Electrocardiograms (ECGs) are sent via facsimile by pediatricians and psychiatrists to cardiologists for assessment. The validity of this method of transmission has not been established. Methods: ECGs were collected from 100 consecutive patients from the cardiology clinic of the Children's Hospital at Montefiore. The ECGs were faxed and also electronically faxed (efax) and printed. Two electrophysiologists (EP1 and EP2) interpreted the intervals on original, faxed, and efaxed ECGs and intervals (RR, PR, and QT) were compared. A three-way analysis of variance to examine differences between raters, among ECG intervals, and among methods (repeated factor) was performed. Because no interaction terms were significant, a Duncan's multiple range test was used to evaluate where differences occurred among the three intervals and three methods, given these main effects were significant. Results: The difference between raters EP1 and EP2 was not significant (P = 0.6681). Although the interval measurements of the faxed and efaxed ECGs were not significantly different from each other (P > 0.05), each was significantly different from the original across all three ECG intervals and both raters (P = 0.0138). The RR interval yielded mean (SD) values for the original, faxed, and efaxed methods of 0.6986 seconds (0.2074), 0.6646 seconds (0.1938), and 0.6838 seconds (0.1935), respectively. For the QT interval, the mean (SD) values for the original, faxed, and efaxed methods were 0.3370 seconds (0.0524), 0.32134 seconds (0.0466), and 0.3284 seconds (0.0515), respectively. Conclusions: ECG transmission via facsimile or efax may introduce significant distortion of the intervals. Alternative means of sending ECGs for interpretation should be considered. PACE 2011; 34:1283–1287)
Virasoro Conformal Blocks and Thermality from Classical Background Fields

We show that in 2d CFTs at large central charge, the coupling of the stress tensor to heavy operators can be re-absorbed by placing the CFT in a non-trivial background metric. This leads to a more precise computation of the Virasoro conformal blocks between heavy and light operators, which are shown to be equivalent to global conformal blocks evaluated in the new background. We also generalize to the case where the operators carry U(1) charges. The refined Virasoro blocks can be used as the seed for a new Virasoro block recursion relation expanded in the heavy-light limit. We comment on the implications of our results for the universality of black hole thermality in AdS3, or equivalently, the eigenstate thermalization hypothesis for CFT2 at large central charge.
Parsing occluded people by flexible compositions

This paper presents an approach to parsing humans when there is significant occlusion. We model humans using a graphical model which has a tree structure building on recent work [32, 6] and exploit the connectivity prior that, even in presence of occlusion, the visible nodes form a connected subtree of the graphical model. We call each connected subtree a flexible composition of object parts. This involves a novel method for learning occlusion cues. During inference we need to search over a mixture of different flexible models. By exploiting part sharing, we show that this inference can be done extremely efficiently requiring only twice as many computations as searching for the entire object (i.e., not modeling occlusion). We evaluate our model on the standard benchmarked “We Are Family” Stickmen dataset and obtain significant performance improvements over the best alternative algorithms.
Statistical and Computational Tradeoffs in Stochastic Composite Likelihood

Maximum likelihood estimators are often of limited practical use due to the intensive computation they require. We propose a family of alternative estimators that maximize a stochastic variation of the composite likelihood function. We prove the consistency of the estimators, provide formulas for their asymptotic variance and computational complexity, and discuss experimental results in the context of Boltzmann machines and conditional random fields. The theoretical and experimental studies demonstrate the effectiveness of the estimators in achieving a predefined balance between computational complexity and statistical accuracy.
Low temperature synthesis and electrode properties of Li4Mn5O12

Stoichiometric L 4 Mn 6 O 12 spinel oxide has been synthesized by an oxidation of Mn 2+ by lithium peroxide in the presence of excess lithium hydroxide followed by firing at T ≤ 500°C. The sample has been characterized by X-ray diffraction, elemental and oxidation state analyses, and thermogravimetric analysis. X-ray results indicate that Li 4 Mn 5 O 12 begins to disproportionate at T > 500°C to give Li 1+x Mn 2-x O 4 (x < 0.33) and Li 2 MnO 3 . The samples fired at 400 and 500°C show in the voltage range 3.3-2.3 V, an initial capacity of 160 and 153 mAh/g, respectively, which is close to the theoretical value. The sample fired at 500°C shows excellent cyclability with <2% capacity decline over 40 cycles.
Ram Accelerator Utilizing Active Projectile

A chemical-propulsion accelerator (either ram- or external-propulsion) system, utilizing a novel, activeprojectile concept is proposed. The projectile comprises the mechanism for compression, storage, and release of high-pressure fluid, that may be either the fuel or the oxidizer used in the ambient combustible gas mixture or inert gas. The shock pattern established by ejection of high-pressure gas from the supersonic projectile into the ambient, combustible-gas mixture serves to ignite the mixture through shock heating and compression, and therefore, to induce the desired propulsive mode (combustion or detonation). The ejected gas then serves to alter locally the ambient mixture, and therefore, can enhance its reactive properties. The present method alse-effers potential application in future aerospace vehicles that will utilize external propulsion modes. A simple model is used to show the practicality of the method and to estimate the lateral size of the combustion zone. The results show that the jet bow shock can ignite the combustible mixture within a radial distance from the body comparable with the barrel radius used in the present ram accelerators. The size of the combustion zone is shown to scale favorably with increasing Mach numbers encountered during the acceleration. The amount of the injectant gas needed is shown to be small. ^
A Phenylcarbene Transfer System

Abstract Treatment of (α,α-dichlorotenzyl)trimethylsilane with potassium fluoride/18-crown-6 ether/diglyme transfers phenyl-chlorocarbene to a number of carbenophiles at room temperature.
Muon cooling R&D

International efforts are under way to design and test a muon ionization cooling channel. The present R&D program is described, and future plans outlined.
Emergent quantum jumps in a nano-electro-mechanical system

We describe a nano-electro-mechanical system that exhibits the 'retroactive' quantum jumps discovered by Mabuchi and Wiseman (1998 Phys. Rev. Lett. 81 4620). This system consists of a Cooper-pair box coupled to a nano-mechanical resonator, in which the latter is continuously monitored by a single-electron transistor or quantum point contact. Further, we show that these kinds of jumps, and the jumps that emerge in a continuous quantum non-demolition measurement, are one and the same phenomena. We also consider manipulating the jumps by applying feedback control to the Cooper-pair box.
Changes in the activities of protein kinases A, C, and M in dog heart and liver following endotoxin administration.

Changes in the activities of protein kinase A (cAMP-dependent), protein kinase C (Ca2+/phospholipid-dependent), and protein kinase M (Ca2+/calmodulin-dependent) in dog heart and liver were studied 4 hr following endotoxin injection. Protein kinases A and C were extracted and partially purified by DEAE-cellulose chromatography. Protein kinase M was extracted and partially purified by DEAE-cellulose, DEAE-Sephacel, and calmodulin-Sepharose chromatography. The results indicate that in the heart, both type I (eluted at low ionic strength) and type II (eluted at high ionic strength) protein kinase A activities were unchanged after endotoxin administration. Cardiac cytosolic protein kinase C activity was increased by 50% (p<0.05) while the membrane-associated protein kinase C activity remained unaltered following endotoxin injection. Cardiac protein kinase M activity was decreased by 38.5% (p<0.01) post endotoxin. In the liver, type I protein kinase A activity was unaffected while type II protein kinase A activity was decreased by 34% (p<0.01) following endotoxin injection. Hepatic cytosolic and membrane-associated protein kinase C activities were inhibited by 37% (p<0.01) and 53% (p<0.01), respectively, 4 hr postendotoxin. Hepatic protein kinase M activity was decreased by 61% (p<0.01) after endotoxin administration. These data indicate that the activities of various protein kinases in the heart and liver were modified by endotoxin administration. Since protein kinases regulate cell function through phosphorylation of various substrate proteins, a modification on protein kinase activities may contribute to the development of organ dysfunction in endotoxin shock.
FMR1 premutation carrier frequency in patients undergoing routine population-based carrier screening: Insights into the prevalence of fragile X syndrome, fragile X-associated tremor/ataxia syndrome, and fragile X-associated primary ovarian insufficiency in the United States

FMR1 premutation carrier frequency in patients undergoing routine population-based carrier screening: Insights into the prevalence of fragile X syndrome, fragile X-associated tremor/ataxia syndrome, and fragile X-associated primary ovarian insufficiency in the United States
Discrete monodromy, pentagrams, and the method of condensation

This paper studies the pentagram map, a projectively natural iteration on the space of polygons. Inspired by a method from the theory of ordinary differential equations, the paper constructs roughly n algebraically independent invariants for the map, when it is defined on the space of n-gons. These invariants strongly suggest that the pentagram map is a discrete completely integrable system. The paper also relates the pentagram map to Dodgson’s method of condensation for computing determinants, also known as the octahedral recurrence.
Highlights of the Rome Workshop on gamma-ray bursts in the afterglow Era

I review some of the highlights of the Rome Workshop on Gamma-Ray Bursts, and discuss some of the questions these results pose about the nature and origin of gamma-ray bursts.
On the Plausibility of “The Neurodevelopmental Hypothesis” of Schizophrenia

Speculation that schizophrenia is associated with abnormal brain development, the so-called neurodevelopmental hypothesis, has become so popular that it is rarely challenged in the literature. This paper critically examines the evidence for this hypothesis, taking primarily the “devil's advocate” position. The evidence from neuroimaging studies, from studies of prenatal and perinatal intrauterine events and of premorbid development are circumstantial with respect to brain development, many studies are methodologically flawed, and most do not exclude alternative explanations. Evidence from postmortem studies of anomalous cytoarchitecture in limbic and prefrontal cortices is especially noteworthy, as a developmental defect is virtually certain if artifacts can be excluded. Unfortunately, the studies responsible for these findings have serious methodological limitations. The neurobiological plausibility of the hypothesis, which might have been predicted to be its weakest aspect, has proved surprisingly unshakeable in a recent series of animal studies. Ironically, the principal weakness of the neurodevelopmental hypothesis at present is the clinical database on which it rests.