cssi/SciSciGPT-SciSciNet huggingface dataset:
The acoustic repertoire of the Southern right whale, a quantitative analysis

Abstract Some 1274 southern right whale sounds were randomly selected and each sound was described by 10 acoustic variables. Two hundred and fifty of these sounds were also ‘labelled’ by the activity, size and sexual composition o the group producing them. Principal components analysis was performed on all the sounds' variables (1274×10) and on the variables for a subset of 823 sounds referred to as calls. Results of the principal components analyses indicate that the sounds can be divided into three major classes: blow sounds, slaps, and calls; and that the repertoire of calls is a continuum with certain types more common than others. The distribution of the ‘labelled’ sounds in the principal components analyses patterns revealed general associations between whale activities and the types of sounds produced.
Three-dimensional orthogonal vector basis functions for time-domain finite element solution of vector wave equations

Three-dimensional (3-D) orthogonal vector basis functions are developed for the time-domain finite element solution of vector wave equations. These basis functions enforce both the tangential continuity of the electric field and the normal continuity of the electric flux. The stability of the resulting time-domain finite element schemes is investigated and demonstrated to be guaranteed. The use of the proposed basis functions completely eliminates the matrix solution at each time step required by the time-domain finite element solution of vector wave equations. The computational cost thereby scales as O(N/sub t/N) with N/sub t/ and N denoting the number of time steps and the number of unknowns, respectively. Defined over tetrahedral elements, the proposed basis functions increase the solution efficiency without compromising the geometry modeling flexibility. Both numerical results and comparison with traditional vector basis functions demonstrate the accuracy as well as the efficiency of the proposed three-dimensional orthogonal vector bases.
N-Alkylation of 2,6-Dichloropurine Hydrochloride with a Variety of Alcohols over Alumina Catalyst

2,6-Dichloropurine hydrochloride reacts with various types of alcohols using different alumina catalysts and converts into its N-9-alkyl-2-chloro-6-hydroxy-9H-purine products to an extent of 49–74%. The product selectivity depends on the stability of carbocation generated from the alcohol. More stable carbocation formulates both N-7 and N-9-alkyl-2,6-dichloropurine products, whereas the less stable carbocation results in exclusively N-9-alkyl-2-chloro-6-hydroxy-9H-purine. The catalytic activity of alumina prepared using the sol-gel method has larger Brunauer, Emmett, and Teller (BET) surface area and hence shows significantly greater catalytic activity than the commercially available alumina samples.
The statistical properties of host load

Understanding how host load changes over time is instrumental in predicting the execution time of tasks or jobs, such as in dynamic load balancing and distributed soft real-time systems. To improve this understanding, we collected week-long, 1 Hz resolution traces of the Digital Unix 5 second exponential load average on over 35 different machines including production and research cluster machines, compute servers, and desktop workstations. Separate sets of traces were collected at two different times of the year. The traces capture all of the dynamic load information available to user-level programs on these machines. We present a detailed statistical analysis of these traces here, including summary statistics, distributions, and time series analysis results. Two significant new results are that load is self-similar and that it displays epochal behavior. All of the traces exhibit a high degree of self-similarity with Hurst parameters ranging from 0.73 to 0.99, strongly biased toward the top of that range. The traces also display epochal behavior in that the local frequency content of the load signal remains quite stable for long periods of time (150-450 s mean) and changes abruptly at epoch boundaries. Despite these complex behaviors, we have found that relatively simple linear models are sufficient for short-range host load prediction.
Nodal Sets of Random Eigenfunctions for the Isotropic Harmonic Oscillator

The expected hypersurface measure H(ZE,h ∩B(r, x)) of nodal sets of random eigenfunctions of eigenvalue E of the semi-classical isotropic harmonic oscillator in balls B(r, x) ⊂ R is determined as h → 0. In the allowed region the volumes are of order h−1, while in the forbidden region they are of order h− 1 2 . 0. Introduction This article is concerned with the semi-classical asymptotics of nodal (i.e. zero) sets of random eigenfunctions of the isotropic Harmonic Oscillator,
ON THE ORIGIN OF COOL CORE GALAXY CLUSTERS: COMPARING X-RAY OBSERVATIONS WITH NUMERICAL SIMULATIONS

To better constrain models of cool core galaxy cluster formation, we have used X-ray observations taken from the Chandra and ROSAT archives to examine the properties of cool core and noncool core clusters, especially beyond the cluster cores. Using an optimized reduction process, we produced X-ray images, surface brightness profiles, and hardness ratio maps of 30 nearby rich Abell clusters (17 cool cores and 13 noncool cores). We show that the use of double β models with cool core surface brightness profiles and single β models for noncool core profiles yield statistically significant differences in the slopes (i.e., β values) of the outer surface brightness profiles, but similar cluster core radii, for the two types of clusters. Hardness ratio profiles as well as spectroscopically fit temperatures suggest that noncool core clusters are warmer than cool core clusters of comparable mass beyond the cluster cores. We compared the properties of these clusters with the results from analogously reduced simulations of 88 numerical clusters created by the adaptive mesh refinement Enzo code. The simulated surface brightness profiles have steeper β-model fits in the outer cluster regions for both cool cores and noncool cores, suggesting additional intracluster medium (ICM) heating is required compared to observed cluster ICMs. Temperature and surface brightness profiles reveal that the simulated clusters are overcooled in their cores. As in the observations, however, simulated hardness ratio and temperature profiles indicate that noncool core clusters are warmer than cool core clusters of comparable mass far beyond the cluster cores. The general similarities between observations and simulations support a model described in Paper I suggesting that noncool core clusters suffered early major mergers destroying nascent cool cores. Differences between simulations and observations will be used to motivate new approaches to feedback in subsequent numerical models.
Outage probability of dual-branch diversity systems in presence of co-channel interference

Outage probability of two low-complexity dual-branch diversity schemes with the consideration of both minimum carrier-to-interference ratio and the carrier-to-noise ratio constraints is investigated. More specifically, closed-form expressions for this outage probability for selection combining and switch and stay combining in single-interferer Rayleigh fading environment are derived, first under the assumption of perfectly estimated independent diversity paths, then by taking into account the effect of branch correlation and outdated/imperfect channel estimates. When applicable, the results obtained as special cases of the offered generic closed-form expressions are compared with those previously reported in the literature. In addition, some numerical examples are provided and discussed.
Clinical engineering education: the internship approach

The importance of a hospital internship for clinical engineers is discussed. The primary objectives of an internship approach are outlined. Specific experiences with a graduate program at Trinity College are included. >
(NH4)AgMoS4: Synthesis, structure and catalytic activity

The synthesis, characterization and crystal structure of (NH4)AgMoS4 is presented. (NH4)AgMoS4 was prepared by the stoichiometric reaction of AgNO3 with (NH4)2MoS4. The black microcrystalline (NH4)AgMoS4 is thermally unstable and contaminated by a phase that analyzes for Ag2MoS4. In the TGA continuous weight loss was observed corresponding to the loss of ammonia gas subsequent loss of sulfur and H2S to give Ag2S and MoS2. In the infrared spectrum of (NH4)AgMoS4, characteristic bands for the ammonium ion at 1350–1400 cm–1 and for the [MoS4]2– group at 460 cm–1 are observed. Crystals of (NH4)AgMoS4 were investigated using a synchroton source. (NH4)AgMoS4 is isostructural to (NH4)CuMoS4 and crystallizes in the tetragonal space group I (Z = 2, a = 7.8740(3), c = 5.7733(4) A). (NH4)AgMoS4 can be used as a catalyst in the syngas conversion to higher alcohols with showing good activity and ethanol selectivity.
Classified Boards, Stability, and Strategic Risk Taking

Classified boards are the focus of recent shareholder activism aimed at improving U.S. corporate governance. Although critics argue that classified boards reduce directors’ effectiveness, proponents counter that they enhance corporate stability, board independence, and long-term strategic risk taking. Based on hand-collected data, this study found that stability was similar for both classified and nonclassified boards and that continuity rates for independent directors were comparable for both categories. The study found as well that companies with classified boards invested less in R&D and other company-specific capital assets. These findings were also true for companies with relatively complex operations that are often considered most likely to benefit from classified boards.
Distributed call admission control in mobile/wireless networks

The major focus of this paper is distributed call admission control in mobile/wireless networks, the purpose of which is to limit the call handoff dropping probability in loss systems or the cell overload probability in lossless systems. Handoff dropping or cell overload are consequences of congestion in wireless networks. Our call admission control algorithm takes into consideration the number of calls in adjacent cells, in addition to the number of calls in the cell where a new call request is made, in order to make a call admission decision. This is done by every base station in a distributed manner without the involvement of the network call processor. The admission condition is simple enough that the admission decision can be made in real time. Furthermore, we show that our distributed call admission control scheme limits the handoff dropping or the cell overload probability to a predefined level almost independent of load conditions. This is an important requirement of future wireless/mobile networks with quality-of-service (QoS) provisioning.
Asymmetric total synthesis of (20R)-homocamptothecin, substituted homocamptothecins and homosilatecans

An efficient asymmetric synthesis of a key DE lactone pyridone intermediate in the synthesis of homocamptothecin is reported. The synthesis is scalable and features a Stille coupling and a Sharpless asymmetric epoxidation as the key steps. The key intermediate has been parleyed into homocamptothecin and an assortment of fluorinated homocamptothecins and homosilatecans (7-silylhomocamptothecins), thereby providing the first asymmetric entry to this important new class of antitumor agents.
A structural characterization of numéraires of convex sets of nonnegative random variables

We introduce the concept of numeraire s of convex sets in \({L^0_{+}}\), the nonnegative orthant of the topological vector space L 0 of all random variables built over a probability space. A necessary and sufficient condition for an element of a convex set \({\mathcal{C} \subseteq L^0_{+}}\) to be a numeraire of \({\mathcal{C}}\) is given, inspired from ideas in financial mathematics.
Unified Electronic Recombination of Ne-like Fe XVII: Implications for Modeling X-Ray Plasmas

Unified recombination cross sections and rates are computed for ( xviii xvii including nonresonant e 1 Fe ) r Fe and resonant (radiative recombination [RR] and dielectronic recombination [DR]) processes in an ab initio manner with relativistic fine structure. The highly resolved theoretical cross sections exhibit considerably more resonance structures than observed in the heavy-ion storage ring measurements at Heidelberg, Germany. Nonetheless, the detailed resonance complexes agree well with experimental results, and the unified rates agree with the sum of experimentally derived DR and theoretical RR rates to »20%, within experimental or theoretical uncertainties. Theoretical results may provide estimates of field ionization of Rydberg levels close to the DR peak and nonresonant background contributions particularly close to the RR peak as . More generally, the unified results E r 0 avoid the physical and practical problems in astrophysical models inherent in the separation of electronic recombination into RR and DR on the one hand and further subdivision into low-energy DR and high-energy Dn p 0 DR in photoionized and collisionally ionized X-ray plasmas on the other hand. Dn 1 0 Subject headings: atomic data — atomic processes — line: formation — X-rays: general
Providing deterministic end-to-end fairness guarantees in core-stateless networks

End-to-end fairness guarantee is an important service semantics that network providers would like to offer to their customers. A network provider can offer such service semantics by deploying a network where each router employs a fair packet scheduling algorithm. Unfortunately, these scheduling algorithms require every router to maintain per-flow state and perform per-packet flow classification; these requirements limit the scalability of the routers. In this paper, we propose the Core-stateless Guaranteed Fair (CSGF) network architecture--the first work-conserving architecture that, without maintaining per-flow state or performing per-packet flow classification in core routers, provides to flows fairness guarantees similar to those provided by a network of core-stateful fair routers.
Extractors for a Constant Number of Independent Sources with Polylogarithmic Min-Entropy

We study the problem of constructing explicit extractors for independent general weak random sources. Given weak sources on n bits, the probabilistic method shows that there exists a deterministic extractor for two independent sources with min-entropy as small as log n+O(1). However, even to extract from a constant number of independent sources, previously the best known extractors require the min-entropy to be at least nδ for any constant δ > 0 [1], [2], [3]. For sources on n bits with min-entropy k ≥ polylog(n), previously the best known extractor needs to use O(log(log n/log k))+O(1) independent sources Li12d. In this paper, we construct the first explicit extractor for a constant number of independent sources on n bits with min-entropy k ≥ polylog(n). Thus, for the first time we get extractors for independent sources that are close to optimal. Our extractor is obtained by improving the condenser for structured somewhere random sources in [3], which is based on a connection between the problem of condensing somewhere random sources and the problem of leader election in distributed computing.
Theoretical Studies of the Electronic Properties of Ceramic Materials

The first-principles orthogonalized linear combination of atomic orbitals (OLCAO) method for electronic structure studies has been applied to a variety of complex inorganic crystals. The theory and the practice of the OLCAO method in the local density approximation are discussed in detail. Recent progress in the study of electronic and optical properties of a large list of ceramic systems are summarized. Eight selected topics on different ceramic crystals focusing on specific points of interest are presented as examples. The materials discussed are AIN, Cu2O, β-Si3N4, Y2O3, LiB3O5, ferroelectric crystals, Fe-B compounds, and the YBa2Cu3O7 superconductor. The results include the band structure, density of states, charge density distribution, spin density distribution, effective charges, total energy and totalenergy-derived results, optical absorption, positron annihilation spectra, and more. Extension of the band theoretical approach to the study of other areas of fundamental ceramic science is also discussed.
Alkene aziridination and epoxidation catalyzed by chiral metal salen complexes

Abstract New chiral metal salen complexes substituted in the 3 position with bulky silyl groups (TMS, TBDMS) have been synthesized. Although some of these complexes catalyzed the epoxidation of unfunctionalized olefins in moderate to high ee's, they catalyzed the aziridination of cis-β-methylstyrene without any asymmetric induction.
Accessing 2-(Hetero)arylmethyl-, -allyl-, and -propargyl-2,1-borazaronaphthalenes: Palladium-Catalyzed Cross-Couplings of 2-(Chloromethyl)-2,1-borazaronaphthalenes

The synthesis of 2-(chloromethyl)-2,1-borazaronaphthalene has provided an opportunity to expand dramatically the functionalization of the azaborines. This azaborinyl building block can serve as the electrophile in palladium-catalyzed cross-coupling reactions to form sp3–sp and sp3–sp2 bonds. The cross-coupling reactions of 2-(chloromethyl)-2,1-borazaronaphthalene with potassium (hetero)aryl- and alkenyltrifluoroborates as well as terminal alkynes provides access to a variety of novel azaborines, allowing a library of pseudobenzylic substituted azaborines to be prepared from one common starting material.
SenCar: An Energy-Efficient Data Gathering Mechanism for Large-Scale Multihop Sensor Networks

In this paper, we propose a new data gathering mechanism for large-scale multihop sensor networks. A mobile data observer, called SenCar, which could be a mobile robot or a vehicle equipped with a powerful transceiver and battery, works like a mobile base station in the network. SenCar starts the data gathering tour periodically from the static data processing center, traverses the entire sensor network, gathers the data from sensors while moving, returns to the starting point, and, finally, uploads data to the data processing center. Unlike SenCar, sensors in the network are static and can be made very simple and inexpensive. They upload sensed data to SenCar when SenCar moves close to them. Since sensors can only communicate with others within a very limited range, packets from some sensors may need multihop relays to reach SenCar. We first show that the moving path of SenCar can greatly affect network lifetime. We then present heuristic algorithms for planning the moving path/circle of SenCar and balancing traffic load in the network. We show that, by driving SenCar along a better path and balancing the traffic load from sensors to SenCar, network lifetime can be prolonged significantly. Our moving planning algorithm can be used in both connected networks and disconnected networks. In addition, SenCar can avoid obstacles while moving. Our simulation results demonstrate that the proposed data gathering mechanism can prolong network lifetime significantly compared to a network that has only a static observer or a network in which the mobile observer can only move along straight lines.
Atom trapping in an interferometrically generated bottle beam trap

We demonstrate an optical bottle beam trap created by interfering two fundamental Gaussian beams with different waists. The beams are derived from a single laser source using a Mach-Zehnder interferometer whose arms have unequal magnifications. Destructive interference of the two beams from the Mach-Zehnder leads to a three-dimensional intensity null at the mutual focus of the beams. We demonstrate trapping of cold cesium atoms in a blue detuned bottle beam trap.
Multisegmented One‐Dimensional Nanorods Prepared by Hard‐Template Synthetic Methods

In the science and engineering communities, the nanoscience revolution is intensifying. As many types of nanomaterials are becoming more reliably synthesized, they are being used for novel applications in all branches of nanoscience and nanotechnology. Since it is sometimes desirable for single nanomaterials to perform multiple functions simultaneously, multicomponent nanomaterials, such as core-shell, alloyed, and striped nanoparticles, are being more extensively researched. Nanoscientists hope to design multicomponent nanostructures and exploit their inherent multiple functionalities for use in many novel applications. This review highlights recent advances in the synthesis of multisegmented one-dimensional nanorods and nanowires with metal, semiconductor, polymer, molecular, and even gapped components. It also discusses the applications of these multicomponent nanomaterials in magnetism, self-assembly, electronics, biology, catalysis, and optics. Particular emphasis is placed on the new materials and devices achievable using these multicomponent, rather than single-component, nanowire structures.
The Long-Term Availability of Railroads Services for U.S. Agriculture

Future customer demands, service availability, and industry investment decisions will shape the modal marketing decisions of the grain-marketing sector. The Delphi technique is used to survey a cross section of grain-industry experts regarding future trends for the grain-marketing sector. The survey produces several interesting expectations, including further consolidation of the rail and elevator industries, increasing prominence of the heavy-axle cars in grain service, the upward trend in rail rates, increased use of market-based car-ordering systems and shuttles, expansion of the short-line rail network, and small market-scale, but large-volume, increases in the share of grain marketed via container. The insights are valuable in understanding the future of the rail grain industry. These expert opinions are important to identify research needs and discuss implications of government policy and market investment that affect the rail grain sector.
A Hybrid Approach for Fast and Accurate Trace Signal Selection for Post-Silicon Debug

A major challenge in post-silicon debug is the lack of observability to the internal signals of a chip. Trace buffer technology provides one venue to address this challenge by online tracing of a few selected state elements. Due to the limited bandwidth of the trace buffer, only a few state elements can be selected for tracing. Recent research has focused on automated trace signal selection problem to maximize restoration of the untraced state elements using the few traced signals. Existing techniques can be categorized into high quality but slow simulation-based techniques and lower quality but much faster metric-based techniques. This paper presents a new trace signal selection technique which has comparable or better quality than simulation-based while it has a fast runtime, comparable to the metric-based techniques.
A FERMIONIC HODGE STAR OPERATOR

A fermionic analogue of the Hodge star operation is shown to have an explicit operator representation in models with fermions, in space–times of any dimension. This operator realizes a conjugation (pairing) not used explicitly in field theory, and induces a metric in the space of wave function(al)s just as in exterior calculus. If made real (hermitian), this induced metric turns out to be identical to the standard one constructed using hermitian conjugation; the utility of the induced complex bilinear form remains unclear.
Store Within a Store

Abstract In a store-within-a-store arrangement, retailers essentially rent out retail space to manufacturers and give them complete autonomy over retail decisions, such as pricing and in-store service. This intriguing retailing format appears in an increasing number of large department stores worldwide. The authors use a theoretical model to investigate the economic incentives a retailer faces when deciding on this arrangement. The retailer's trade-off is between channel efficiency and interbrand competition, moderated by returns to in-store service and increased store traffic. The retailer cannot credibly commit to the retail prices and service levels that the manufacturers effect in an integrated channel, so it decides instead to allow them to set up stores within its store. Thus, the stores-within-a-store phenomenon emerges when a powerful retailer, ironically, gives manufacturers autonomy in its retail space. An extension of the model to the case of competing retailers shows that the store-within-a-st...
Measurement of local strains in intervertebral disc anulus fibrosus tissue under dynamic shear : contributions of matrix fiber orientation and elastin content

Shear strain has been implicated as an initiator of intervertebral disc anulus failure, however a clear, multi-scale picture of how shear strain affects the tissue microstructure has been lacking. The purposes of this study were to measure microscale deformations in anulus tissue under dynamic shear in two orie ntations, and to determine the role of elastin in regulating these deformations. Bovine AF tissue was simultaneously shear loaded and imaged using confocal microscopy following either a buffer or elastase treatment. Digital image analysis was used to track through time local shear strains in specimens sheared transversely, and stretch and rotation of collagen fiber bundles in specimens sheared circumferentially. The results of this study suggest that sliding does not occur between AF plies under shear, and that interlamellar connections are governed by collagen and fibrilin rather than elastin. The transverse shear modulus was found to be approximately 1.6 times as high in plies the direction of the collagen fibers as in plies across them. Under physiological levels of in-plane shear, fiber bundles stretched and re-oriented linearly. Elastin was found to primarily stiffen plies transversely. We conclude that alterations in the elastic fiber network, as found with IVD herniation and degeneration, can therefore be expected to significantly influence the AF response to shear making it more susceptible to micro failure under bending or torsion loading.
The Effects of Fluid Viscosity on the Kinematics and Material Properties of C. elegans Swimming at Low Reynolds Number

The effects of fluid viscosity on the kinematics of a small swimmer at low Reynolds numbers are investigated in both experiments and in a simple model. The swimmer is the nematode Caenorhabditis elegans, which is an undulating roundworm approximately 1 mm long. Experiments show that the nematode maintains a highly periodic swimming behavior as the fluid viscosity is varied from 1.0 to 12 mPa s. Surprisingly, the nematode’s swimming speed (~0.35 mm/s) is nearly insensitive to the range of fluid viscosities investigated here. However, the nematode’s beating frequency decreases to an asymptotic value (~1.7 Hz) with increasing fluid viscosity. A simple model is used to estimate the nematode’s Young’s modulus and tissue viscosity. Both material properties increase with increasing fluid viscosity. It is proposed that the increase in Young’s modulus may be associated with muscle contraction in response to larger mechanical loading while the increase in effective tissue viscosity may be associated with the energy necessary to overcome increased fluid drag forces.
ULTRAFILTERS IN REVERSE MATHEMATICS

We extend theories of reverse mathematics by a non-principal ultrafilter, and show that these are conservative extensions of the usual theories ACA0, ATR0, and ${\bf{\Pi^1_1{-}{\rm CA}_0}}$.
Identifying the protein folding nucleus using molecular dynamics.

Molecular dynamics simulations of folding in an off-lattice protein model reveal a nucleation scenario, in which a few well-defined contacts are formed with high probability in the transition state ensemble of conformations. Their appearance determines folding cooperativity and drives the model protein into its folded conformation. Amino acid residues participating in those contacts may serve as "accelerator pedals" used by molecular evolution to control protein folding rate.
Learning and efficiency in games with dynamic population

We study the quality of outcomes in repeated games when the population of players is dynamically changing, and where participants use learning algorithms to adapt to the dynamic environment. Price of anarchy has originally been introduced to study the Nash equilibria of one-shot games. Many games studied in computer science, such as packet routing or ad-auctions, are played repeatedly. Given the computational hardness of Nash equilibria, an attractive alternative in repeated game settings is that players use no-regret learning algorithms. The price of total anarchy considers the quality of such learning outcomes, assuming a steady environment and player population, which is rarely the case in online settings.In this paper we analyze efficiency of repeated games in dynamically changing environments. An important trait of learning behavior is its versatility to changing environments, assuming that the learning method used is adaptive, i.e., doesn't rely too heavily on experience from the distant past. We show that, in large classes of games, if players choose their strategies in a way that guarantees low adaptive regret, high social welfare is ensured, even under very frequent changes.A main technical tool for our analysis is the existence of a solution to the welfare maximization problem that is both close to optimal and relatively stable over time. Such a solution serves as a benchmark in the efficiency analysis of learning outcomes. We show that such a stable and close to optimal solution exists for many problems, even in cases when the exact optimal solution can be very unstable. We further show that a sufficient condition on the existence of stable outcomes is the existence of a differentially private algorithm for the welfare maximization problem. Hence, we draw a strong connection between differential privacy and high efficiency of learning outcomes in frequently changing repeated games.We demonstrate our techniques by focusing on two classes of games as examples: independent item auctions and congestion games. In both applications we show that adaptive learning guarantees high social welfare even with surprisingly high churn in the player population.
Stereoselective synthesis of 2,3,4-trisubstituted tetrahydrofurans

Abstract The stereoselective synthesis of trisubstituted tetrahydrofurans from benzyl diazoacetate and α-alkyl-β-benzyloxyaldehydes or α-alkyl-β-(triethylsilyl)oxyaldehydes is described.
Restriction of A-discriminants and dual defect toric varieties

We study the A-discriminant of toric varieties. We reduce its computation to the case of irreducible configurations and describe its behavior under specialization of some of the variables to zero. We give characterizations of dual defect toric varieties in terms of their Gale dual and classify dual defect toric varieties of codimension less than or equal to four.
Simulation of electric machinery and power electronics interfacing using MATLAB/SIMULINK

This paper introduces power electronic and electric machines toolboxes based on the MATLAB/SIMULINK simulation package. Simulation components include DC-DC converters, power-factor-correction rectifiers, field-oriented and direct torque control methods for electric drives, induction machines, DC machines, synchronous machines, and more complete systems. Switching and averaged power electronic models are included, as well as dynamic and steady-state machine models. The toolboxes make possible the straightforward construction and simulation of complex dynamic systems involving power electronic components and machines.
Harmonic cosmology: how much can we know about a universe before the big bang?

Quantum gravity may remove classical space–time singularities and thus reveal what a universe at the big bang could be like. In loop quantum cosmology, an exactly solvable model is available, which allows one to address precise dynamical coherent states and their evolution in such a setting. It is shown here that quantum fluctuations before the big bang are generically unrelated to those after the big bang. While this is derived only in the solvable model, it presents the case of the strongest control on coherence properties; adding ingredients to a realistic model could only increase the complexity. A reliable determination of pre-big bang quantum fluctuations of geometry would thus require exceedingly precise observations.
Mode-coupling theory and beyond: A diagrammatic approach

For almost thirty years, mode-coupling theory has been the most widely discussed and used but also the most controversial theory of the glass transition. In this paper we briefly review the reasons for both its popularity and its controversy. We emphasize the need for the development of approaches that would be able to evaluate corrections to and extensions of the existing (standard) mode-coupling theory. Next, we review our diagrammatic formulation of the dynamics of interacting Brownian particles. We show that within this approach the standard mode-coupling theory can be derived in a very simple way. Finally, we use our diagrammatic approach to calculate two corrections to the mode-coupling theory's expression for the so-called irreducible memory function. These corrections involve re-summations of well defined classes of non-mode-coupling diagrams.
Endotoxin and cancer

A exposicao a endotoxina, componente de paredes celulares bacterianas gram-negativas, e muito comum em plantas industriais e no meio ambiente. Ambientes de alta exposicao incluem fazendas de criacao de animais, instalacoes texteis de algodao e moinhos. Neste artigo, revemos estudos experimentais, epidemiologicos e ensaios clinicos sobre a hipotese de que a endotoxina previne o câncer. Desde os anos 70, estudos epidemiologicos em texteis de algodao e outros grupos ocupacionais expostos a endotoxina demonstram reducao no risco de câncer de pulmao. Pesquisa experimental de toxicologia animal e ensaios terapeuticos limitados em pacientes com câncer dao suporte para um potencial anticarcinogenico. Os mecanismos biologicos anticarcinogenicos de base ainda nao sao completamente compreendidos, mas acredita-se que incluem recrutamento e ativacao de celulas imunologicas e mediadores pro-inflamatorios (ex.: fator de necrose tumoral α e interleucina-1 e - 6). Devido ao estagio atual de conhecimento, seria prematuro recomendar a endotoxina como agente quimiopreventivo. Porem, pesquisas epidemiologicas e experimentais que esclarecam relacoes de dosagem-efeito e exposicao-relacoes temporais podem trazer beneficios para a saude publica e a biomedicina basica.
The Brown Dwarf Desert at 75-1200 AU

We present results of a comprehensive infrared coronagraphic search for substellar companions to nearby stars. The research consisted of (1) a 178-star survey at Steward and Lick observatories, with optical follow-up from Keck Observatory, capable of detecting companions with masses greater than 30 MJ, and semimajor axes between about 140 to 1200 AU; (2) a 102-star survey using the Keck Telescope, capable of detecting extrasolar brown dwarfs and planets typically more massive than 10 MJ, with semimajor axes between about 75 and 300 AU. Only one brown dwarf companion was detected, and no planets. The frequency of brown dwarf companions to G, K, and M stars orbiting between 75 and 300 AU is measured to be 1% ± 1%, the most precise measurement of this quantity to date. The frequency of massive (greater than 30 MJ) brown dwarf companions at 120–1200 AU is found to be f = 0.7% ± 0.7%. The frequency of giant planet companions with masses between 5 and 10 MJ orbiting between 75 and 300 AU is measured here for the first time to be no more than ~3%. Together with other surveys that encompass a wide range of orbital separations, these results imply that substellar objects with masses between 12 and 75 MJ form only rarely as companions to stars. Theories of star formation that could explain these data are only now beginning to emerge.
Environmental Factors and Children's Malnutrition in Ethiopia

Ethiopia has one of the highest child malnutrition rates in the world. A considerable effort to monitor child malnutrition rates over the last two decades shows that, despite some improvements, approximately half of the children under five are still malnourished. Much of the burden of deaths resulting from malnutrition, estimated to be over half of childhood deaths in developing countries, can be attributed to just mild and moderate malnutrition. Several biological and social economic factors contribute to malnutrition. Using the 2000 Ethiopia Demographic and Health Survey data, this study examines the impact of access to basic environmental services, such as water and sanitation on the probability children are stunted and underweight. The focus is on the impact of externalities associated with access to these services. We find that biological factors, such as child's age and mother's height, and social economic factors, such as household wealth and mother's education, are important determinants of a child's nutritional status. This is consistent with the findings of most studies in this literature. With respect to the environmental factors, we find that there are indeed significant externalities associated with access to water and sanitation at the community level. The external impacts of community level of access to these services are an important determinant of the probability a child is underweight. Our results also show that the external impact of access to water is larger for children living in rural areas.
Growth and Election Outcomes in a Developing Country

With the exception Brander and Drazen (2008), who use a comprehensive cross-country database consisting of both developed and developing countries, the hypothesis that rapid growth helps incumbents win elections has been tested exclusively for the developed countries (e.g., Ray Fair 1978). But since sustained rapid growth offers the prospect of pulling vast numbers of the voters out of poverty within a generation, such an effect is far more likely to be present in the developing rather than developed countries. In this paper, we offer the first test of the hypothesis on a large developing and poor country, India, which has seen its economy grow 8 to 9 percent recently. We first generalize the Fair model to allow for multiple candidates instead for just two and then test it using cross-state data. We find quantitatively large and statistically robust effect of growth on the prospects of the candidates of the state incumbent parties to win elections. Specifically, we use the data on 422 candidates in the 2009 parliamentary elections and show that the candidates of incumbent parties in high-growth states have much better prospects of victory than those in low-growth states.
Archaeology of Eukaryotic DNA Replication

Recent advances in the characterization of the archaeal DNA replication system together with comparative genomic analysis have led to the identification of several previously uncharacterized archaeal proteins involved in replication and currently reveal a nearly complete correspondence between the components of the archaeal and eukaryotic replication machineries. It can be inferred that the archaeal ancestor of eukaryotes and even the last common ancestor of all extant archaea possessed replication machineries that were comparable in complexity to the eukaryotic replication system. The eukaryotic replication system encompasses multiple paralogs of ancestral components such that heteromeric complexes in eukaryotes replace archaeal homomeric complexes, apparently along with subfunctionalization of the eukaryotic complex subunits. In the archaea, parallel, lineage-specific duplications of many genes encoding replication machinery components are detectable as well; most of these archaeal paralogs remain to be functionally characterized. The archaeal replication system shows remarkable plasticity whereby even some essential components such as DNA polymerase and single-stranded DNA-binding protein are displaced by unrelated proteins with analogous activities in some lineages.
Raids, Rewards, and Reputations in the Market for Managerial Talent

We find that executives who jump to chief executive officer (CEO) positions at new employers come from firms that exhibit aboveaverage stock price performance. This relationship is more pronounced for more senior executives. No such relationship exists for jumps to non-CEO positions. Stock options and restricted stock do not appear to significantly affect the likelihood of jumping ship, but the existence of an "heir apparent" on the management team increases the likelihood that executives will leave for non-CEO positions elsewhere. Hiring grants used to attract managers are correlated with the equity position forfeited at the prior employer and with the prior employer's performance. Copyright 2003, Oxford University Press.
Postclassic Petén Maya bow-and-arrow use as revealed by immunological analysis

Abstract The bow-and-arrow was a widely used weapon in the Postclassic and Contact periods in the Maya lowlands. A sample of 108 arrow points from varied archaeological contexts in the lakes region of central Peten, northern Guatemala, was submitted for cross-over immunoelectrophoresis (CIEP) analysis. Analysis resulted in 25 positive matches to available antisera for a wide range of local and introduced fauna, from small and large land mammals to avians. These findings indicate possible uses in subsistence and ritual, as well as the first immunological identification of human proteins from projectile weaponry in Mesoamerica. This study did not reveal strong correlations between targeted fauna and point morphology, although larger points were likely used for larger game.
Local permit ownership in Alaska salmon fisheries

Abstract Changes in ownership of limited entry permits by “local” residents of the region where a fishery occurs may have significant economic and social implications for fishery-dependent regions. This paper examines changes in local permit ownership in Alaska salmon fisheries, for which a long-term decline in rural local permit ownership is an important policy concern. Theoretically, permit markets allocate permits over time to the individuals who are willing to pay the most for them. Any factors that differentially affect what local and non-local residents are willing to pay for permits may affect the equilibrium share of permits held by local residents. For remote rural fisheries in particular, these may include differences between local and non-local residents with respect to access to and costs of financing permits and boats, costs of travel to the fishery, opportunity costs of participation in the fishery, and many other factors. As a fishery increases in profitability, differences between local and non-local residents in access to financing matter more while differences in costs of travel and opportunity costs matter less in the relative ranking of what local and non-local residents are willing to pay for permits. This tends to increase the share of non-local residents among buyers willing to pay the market price for permits, reducing the equilibrium share of permits held by local residents. This leads to a conflict between two important policy goals: increasing fishery profitability and maintaining rural local permit ownership. Consistent with predictions of this theory, the local share of permit ownership in Alaska salmon fisheries is negatively related to permit prices (an indicator of fishery profitability).
Credit Rating Changes and Institutional Trading

Proactive bond-rating changes, especially downgrades, are associated with heightened equity market trading by institutional investors. Institutional sell minus buy imbalance jumps from almost 0 to nearly 13% of the total volume in the 5-day period preceding downgrades, controlling for other determinants of volume. Trades consistent with credit-rating changes are more profitable than those consistent with equity analysts’ recommendations. Rating changes have an incremental explanatory power for overall profitability of institutional trades controlling for past returns, momentum, Fama–French factors, and regulation fair disclosure in periods both before and after the financial crisis.
Density of the SO(3) TQFT Representation of Mapping Class Groups

We show that for an odd prime r>3 and an integer g>1, in the projective representation given by the SO(3) Witten-Reshitikhin-Turaev theory at an rth root of unity, the image of the mapping class group of a surface of genus g is dense.
Public policy and health insurance choices of the elderly: evidence from the medicare buy-in program

This study provides evidence on health insurance decisions of senior citizens. Nearly all senior citizens have health insurance coverage through Medicare, but poor seniors may also qualify for Medicaid that fills many gaps in Medicare coverage. Since 1987, the Medicaid program has expanded eligibility. Using the SIPP, I find that Medicaid eligibility increased from 8.7% in 1987 to 12.4% in 1995. For every 100 elderly who became eligible, approximately 50 took up Medicaid, but more than 30 dropped private coverage, resulting in crowd-out of 60%. Crowd-out came from individuals dropping privately purchased health insurance rather than dropping employer-provided retiree health insurance. The roles of asset tests, health status, and the panel structure of the SIPP are also explored. I find that a major strength of the SIPP is in its point-in-time asset information for determining Medicaid eligibility, while the changing income and demographic information over the course of the 2-year panel adds little insight beyond cross-sectional data. © 2000 Elsevier Science S.A. All rights reserved.
Enantioselective hydrolysis of 1-arylallyl acetates catalyzed by Candida antarctica lipase

Abstract ( R )-1-Arylallyl alcohols were obtained with excellent enantioselectivities via kinetic resolution of the corresponding acetates using immobilized Candida antarctica lipase. The scope and limitations of this reaction were investigated. The best results are obtained using the water/acetonitrile solvent system, and the reaction tolerates a variety of aryl and heteroaryl substituents.
Aerodynamic design optimization on unstructured grids with a continuous adjoint formulation

A continuous adjoint approach for obtaining sensitivity derivatives on unstructured grids is developed and analyzed. The derivation of the costate equations is presented, and a second-order accurate discretization method is described. The relationship between the continuous formulation and a discrete formulation is explored for inviscid, as well as for viscous flow. Several limitations in a strict adherence to the continuous approach are uncovered, and an approach that circumvents these difficulties is presented. The issue of grid sensitivities, which do not arise naturally in the continuous formulation, is investigated and is observed to be of importance when dealing with geometric singularities. A method is described for modifying inviscid and viscous meshes during the design cycle to accommodate changes in the surface shape. The accuracy of the sensitivity derivatives is established by comparing with finite-difference gradients and several design examples are presented.
UCDs as Probes of the Major and Minor Merger Histories of Galaxies

Two competing theories posit that Ultra Compact Dwarfs (UCDs) form either as the stripped nuclei of dwarf galaxies or as giant globular clusters (GGCs) associated with the largest globular cluster (GC) systems. By focussing on the field and group environments where young UCDs may be most common, we have discovered the first UCD that is clearly the result of recent ( Gyr ago) stripping of a companion galaxy during a minor galaxy merger. However, we have also found a definitive case of a multiple-UCD system created via GC formation processes, which are likely associated with major galaxy mergers.