cssi/SciSciGPT-SciSciNet huggingface dataset:
DYNAMICAL ROTATIONAL INSTABILITY AT LOW T/W

Dynamical instability is shown to occur in differentially rotating polytropes with N = 3.33 and T/|W| 0.14. This instability has a strong m = 1 mode, although the m = 2, 3, and 4 modes also appear. Such instability may allow a centrifugally hung core to begin collapsing to neutron star densities on a dynamical timescale. The gravitational radiation emitted by such unstable cores may be detectable with advanced ground-based detectors, such as LIGO-II. If the instability occurs in a supermassive star, it may produce gravitational radiation detectable by the space-based detector LISA.
Do Income Tax-Related Deficiencies in Publicly Disclosed PCAOB Part II Reports Influence Audit Client Financial Reporting of Income Tax Accounts?

ABSTRACT: Deloitte's 2007 PCAOB Part II report identifies, among other issues, concerns related to the audit firm's quality controls with respect to auditing income tax accounts. We investigate whether Deloitte's actions to remediate the PCAOB's concerns are associated with changes to their clients' financial reporting for income taxes. We find that Deloitte's clients increased the reported valuation allowance on deferred tax assets and increased the reported reserve for uncertain tax benefits (UTBs) in response to increased auditor scrutiny over income tax accounts. Additionally, we find that in subsequent periods, Deloitte's clients report valuation allowances and UTB balances that are not significantly different than other annually inspected auditors, consistent with Deloitte changing the quality controls related to audits of income tax accounts after the failed remediation of the 2007 Part II report.
(0,2) Chiral Liouville Field Theory

As an existence proof of the (0, 2) heterotic supercurrent supermultiplets in (1+1)-dimensional quantum field theories which are consistent with the warped superconformal algebra, we construct the (0, 2) chiral Liouville field theories. The two distinct possibilities of the heterotic supercurrent supermultiplets are both realized.
MPs for Sale? Returns to Office in Postwar British Politics

Many recent studies show that firms profit from connections to influential politicians, but less is known about how much politicians financially benefit from wielding political influence. We estimate the returns to serving in Parliament, using original data on the estates of recently deceased British politicians. Applying both matching and a regression discontinuity design to compare Members of Parliament (MPs) with parliamentary candidates who narrowly lost, we find that serving in office almost doubled the wealth of Conservative MPs, but had no discernible financial benefits for Labour MPs. Conservative MPs profited from office largely through lucrative outside employment they acquired as a result of their political positions; we show that gaining a seat in Parliament more than tripled the probability that a Conservative politician would later serve as a director of a publicly traded firm—enough to account for a sizable portion of the wealth differential. We suggest that Labour MPs did not profit from office largely because trade unions collectively exerted sufficient control over the party and its MPs to prevent members from selling their services to other clients.
CHEMISTRY OF GLYCOSYL TRIFLATES: SYNTHESIS OF β-MANNOPYRANOSIDES

Among the numerous and varied glycosyl donors known, the glycosyl sulfonates have been somewhat neglected in recent years, despite their considerable potential in stereoselective glycosylation havi...
The diverse chemistry of oxazol-5-(4H)-ones.

The assembly of structurally diverse scaffolds via substrate controlled diversity oriented synthesis (DOS) has proven to be an effective tool in the discovery of novel biologically important compounds. This tutorial review aims to summarize some of the more recent applications of oxazolones as a general template for the stereoselective syntheses of amino acids and heterocyclic scaffolds. A brief introduction covers a short history, nomenclature and general reactivity of oxazolones. The main body of this tutorial review highlights several applications of oxazolones as starting blocks for the diverse and stereoselective synthesis of amino acids, oxazoles, β-lactams, pyrroles, imidazolines, pyrrolines, and imidazoles.
Synthesis and structure of benzoboroxoles: novel organoboron heterocycles

Abstract Benzoboroxoles (5) can be prepared from the readily available o-bromobenzyl alcohols via dilithiation followed by reaction with triisopropylborate. X-Ray structural analysis of 1-hydroxy-3(1H)-1,2-benzoboroxole (5a) as well as the results of ab initio molecular orbital calculations indicate a planar structure of the boron center with a relatively short CB bond. Preliminary results regarding the chemistry of benzoboroxoles are also reported.
Quasi-Coherent Oscillations in the Extreme Ultraviolet Flux of the Dwarf Nova SS Cygni

Quasi-coherent oscillations have been detected in the extreme ultraviolet flux of the dwarf nova SS Cygni during observations with the Extreme Ultraviolet Explorer satellite of the rise and plateau phases of an anomalous outburst in 1993 August and a normal outburst in 1994 June/July. On both occasions, the oscillation turned on during the rise to outburst and persisted throughout the observation. During the 1993 outburst, the period of the oscillation fell from 9.3 s to 7.5 s over an interval of 4.4 days; during the 1994 outburst, the period fell from 8.9 s to 7.19 s (the shortest period ever observed in SS Cyg, or any other dwarf nova) within less than a day, and then rose to 8.0 s over an interval of 8.0 days. For both outbursts, the period P of the oscillation was observed to correlate with the 75-120 A count rate IEUV according to P ∝ IEUV−0.094. A magnetospheric model is considered to reproduce this variation. It is found that an effective high-order multipole field is required, and that the field strength at the surface of the white dwarf is 0.1-1 MG. Such a field strength is at the lower extreme of those measured or inferred for bona fide magnetic cataclysmic variables.
A General and Extensible Unstructured Mesh Adjoint Method

An efficient method for computing adjoint based, functional sensitivities has been developed in a manner that minimizes maintenance required to reflect subsequent updates to the function code. This method has been applied to an unstructured mesh, Navier Stokes flow solver, within an object-oriented, polymorphic framework. The use of Complex Taylor Series Expansion (CTSE), within this framework, allows for flexible application in the computation of derivatives.
Next generation IR magnets for hadron colliders

Brookhaven National Laboratory (BNL) is developing "React & Wind" designs and technology for building long high field accelerator magnets. This paper presents the R&D program for interaction region (IR) magnets made with "Rutherford" cable for the luminosity upgrade of the Large Hadron Collider (LHC). This paper will introduce a few new end design concepts that make the bend radius of the cable in the end independent of the coil aperture. These designs are suitable for building magnets with "React & Wind" technology.
Private Provision of Highways: Economic Issues

Abstract This paper reviews issues raised by the use of private firms to finance, build, and/or operate highways—issues including cost of capital, level and structure of tolls, and adaptability to unforeseen changes. The public sector’s apparent advantage in cost of capital is at least partly illusory due to differences in tax liability and constraints on the supply of public capital. The evidence for lower costs of construction or operation by private firms is slim. Private firms are likely to promote more efficient pricing. Effective private road provision depends on well‐structured franchise agreements that allow pricing flexibility, restrain market power, enforce a sound debt structure, promote transparency, and foster other social goals.
Optical Measurements of Unducted Fan Flutter

A nonintrusive optical method is described for flutter vibrations in unducted fan or propeller rotors and provides detailed spectral results for two flutter modes of a scaled unducted fan. The measurements were obtained in a high-speed wind tunnel. A single-rotor and a dual-rotor counterrotating configuration of the model were tested; however, only the forward rotor of the counterrotating configuration fluttered. Conventional strain gages were used to obtain flutter frequency; optical data provided complete phase results and an indication of the flutter mode shape through the ratio of the leading- to trailing-edge flutter amplitudes near the blade tip. In the transonic regime exhibited some features that are usually associated with nonlinear vibrations. Experimental mode shape and frequencies were compared with calculated values that included centrifugal effects.
Child day‐labourers in agriculture: evidence from farm accounts, 1740–1850

While child labour has always been an important part of the industrial revolutionstory, there is little quantitative evidence about the number of child workers in the1740–1850 period. This article estimates trends in the percentage of the agriculturalday-labouring workforce that were children. By using the wage level to identify childworkers, it is possible to estimate child labour for a large sample of English farms. Itis found that girls were rarely employed as day-labourers, while boys were employedabout as frequently as women. The percentage of boys in the day-labour workforceincreased until the 1820s and then declined.
Dynamics of strongly magnetized ejecta in gamma-ray bursts

We consider dynamical scales in magnetized GRB outows, using the solutions to the Riemann problem of expanding arbitrarily magnetized outows (Lyutikov 2010). For high ejecta magnetization, the behavior of the forward shock closely resembles the so-called thick shell regime of the hydrodynamical expansion. The exception is at small radii, where the motion of the forward shock is determined by the dynamics of subsonic relativistic outows. The behaviors of the reverse shock is dierent in uid and magnetized cases: in the latter case, even for medium magnetization, 1, the reverse shock forms at fairly large distances, and may never form in a wind-type external density prole.
Synthesis and structure-activity relationships of thieno[2,3-d]pyrimidine-2,4-dione derivatives as potent GnRH receptor antagonists.

Abstract The synthesis and SAR studies of thieno[2,3- d ]pyrimidine-2,4-diones as human GnRH receptor antagonists to treat reproductive diseases are discussed. It was found that the 2-(2-pyridyl)ethyl group on the 5-aminomethyl functionality of the core structure was a key feature for good receptor binding activity. SAR study of the 6-(4-aminophenyl) group suggests that hydrophobic substituents were preferred. The best compound from this series had binding affinity ( K i ) of 0.4 nM to the human GnRH receptor.
Unconstitutional Police Searches and Collective Responsibility

Jon Gould and Stephen Mastrofski document astonishingly high rates of unconstitutional police searches in their groundbreaking article, “Suspect Searches: Assessing Police Behavior Under the U.S. Constitution.” By their conservative estimate, 30% of the 115 police searches they studied— searches that were conducted by officers in a department ranked in the top 20% nationwide, that were systematically observed by trained field observers, and that were coded by Gould, Mastrofski, and a team including a state appellate judge, a former federal prosecutor, and a government attorney—violated Fourth Amendment prohibitions on searches and seizures. The majority of the unconstitutional searches—31 out of 34— were invisible to the courts, having resulted in no arrest, charge, or citation. In fact, the rate of unconstitutional searches was highest for suspects who were released—44% versus 7% of arrested or cited suspects. Focusing exclusively on stop-and-frisk searches, an even higher proportion— 46%—were unconstitutional. Moreover, 84% of the searches involved black suspects. The searches were conducted and observed in the early 1990s in the midst of an ongoing war on drugs, during a period of increased police discretion nationwide. The study paints a troubling picture of police practices and raises a number of difficult questions about discretionary policing.2 Gould and Mastrofski’s findings have a disturbingly familiar ring to them. In a somewhat analogous context—stop-and-frisk searches conducted in New York City during the late 1990s—research similarly
Azimuthal asymmetry in lepton-proton scattering at high energies.

We consider the azimuthal angular dependence of the distribution of final-state hadrons in high-energy lepton-proton scattering. The distribution displays an azimuthal asymmetry due to both perturbative and nonperturbative effects. At the large momentum transfers attainable, for example, at the DESY $\mathrm{ep}$ collider HERA we expect the perturbative effects to dominate and constitute a clear test of QCD.
ANCHOR - self-configuring robotic network

A challenging task for a robotic radio network is to establish the connectivity among a set of entities (humans or radio nodes) in an unknown environment with minimum number of robots. The main difficulty is that the locations of the entities and the radio connectivities between the physical locations are not known in advance. We represent the problem by a topological graph of locations with known access links but unknown radio links and develop a novel ANCHOR algorithm for a set of autonomous robots to discover radio links dynamically and self-organize a radio network to connect the given entities with the least number of robots. We show in simulation analysis the algorithm scale near-linearly with maximum number of connected hops away from the terminals. Experiment also shows performance improvement with increasing number of robots.
The Making of the standard model

I have been asked to review the history of the formation of the Standard Model. It is natural to tell this story as a sequence of brilliant ideas and experiments, but here I will also talk about some of the misunderstandings and false starts that went along with this progress, and why some steps were not taken until long after they became possible. The study of what was not understood by scientists, or was understood wrongly, seems to me often the most interesting part of the history of science. Anyway, it is an aspect of the Standard Model with which I am very familiar, for as you will see in this talk, I shared in many of these misunderstandings. I’ll begin by taking you back before the Standard Model to the 1950’s. It was a time of frustration and confusion. The success of quantum electrodynamics in the late 1940s had produced a boom in elementary particle theory, and then the market crashed. It was realized that the four-fermion theory of weak interactions had infinities that could not be eliminated by the technique of renormalization, which had worked so brilliantly in electrodynamics. The four-fermion theory was perfectly good as a lowest-order approximation, but when you tried to push it to the next order of perturbation theory you encountered unremovable infinities. The theory of strong interactions had a different problem; there was no difficulty i n constructing renormalizable theories of the strong interactions like the original Yukawa theory but, because the strong interactions are strong, perturbation theory was useless, and one could do no practical calculations with these theories. A deeper problem with our understanding of both the weak and the strong interactions was that there was no rationale for any of these theories. The weak interaction theory was simply cobbled together to fit what experimen
On the Origin of the High-Ionization Intermediate-Velocity Gas toward HD 14434

We present Far-Ultraviolet Spectroscopic Explorer and Space Telescope Imaging Spectrograph observations of high-ionization interstellar absorption toward HD 14434 (l ¼ 135=1, b ¼� 3=8; d � 2:3 kpc), an O5.5 V star in the Perseus OB1 association. Intermediate-velocity interstellar Si iv and C iv absorption is present at VLSR ¼� 67 km s � 1 , while low-ionization gas associated with the Perseus arm is detected at about � 50 km s � 1 . Neither N v nor O vi is detected at VLSR ¼� 67 km s � 1 , although Al iii and Fe iii, tracers of warm ionized gas, are seen. The high-ion column densities in the � 67 km s � 1 component are log½NðC ivÞ� ¼ 13:92 � 0:02 cm � 2 ,l og½NðSi ivÞ� ¼ 13:34 � 0:02 cm � 2 ,l og½NðN vÞ� � 12:65 cm � 2 ,a nd log½NðO viÞ� � 13:73 cm � 2 (3 � limits). The observed Civ/Siiv ratio of 3:8 � 0:3 in this intermediate-velocity cloud (IVC) is similar to the Galactic average (4:3 � 1:9). Our analysis of the Si iv and C iv line widths yields a temperature of T � 10; 450 � 3400 K for this component. At this low temperature, neither Si iv nor C iv can be produced via collisions. We investigate several photoionization models to explain the intermediatevelocity Si iv and C iv absorption toward HD 14434. Photoionization models employing cooling of a hot (T � 10 6 K) diffuse plasma as the source of ionizing radiation reproduce the observed properties of the IVC toward HD 14434 quite well. The hot plasma responsible for the ionizing radiation in these models may be attributed to hot gas contained in a supershell in or near the Perseus arm or from a more generally distributed hot ionized medium. Subject headings: ISM: abundances — ISM: atoms — ISM: structure — open clusters and associations: individual (Perseus OB1) — stars: individual (HD 14434) — ultraviolet: ISM
Design considerations for high-current superconducting ion linacs

Superconducting linacs may be a viable option for high-current applications such as fusion materials irradiation testing, spallation neutron source, transmutation of radioactive waste, tritium production, and energy production. These linacs must run reliably for many years and allow easy routine maintenance. Superconducting cavities operate efficiently with high cw gradients, properties which help to reduce operating and capital costs, respectively. However, cost-effectiveness is not the sole consideration in these applications. For example, beam impingement must be essentially eliminated to prevent unsafe radioactivation of the accelerating structures, and thus large apertures are needed through which to pass the beam. Because of their high efficiency, superconducting cavities can be designed with very large bore apertures, there by reducing the effect of beam impingement. Key aspects of high-current cw superconducting linac designs are explored in this context. >
Image labeling on a network: using social-network metadata for image classification

Large-scale image retrieval benchmarks invariably consist of images from the Web. Many of these benchmarks are derived from online photo sharing networks, like Flickr, which in addition to hosting images also provide a highly interactive social community. Such communities generate rich metadata that can naturally be harnessed for image classification and retrieval. Here we study four popular benchmark datasets, extending them with social-network metadata, such as the groups to which each image belongs, the comment thread associated with the image, who uploaded it, their location, and their network of friends. Since these types of data are inherently relational, we propose a model that explicitly accounts for the interdependencies between images sharing common properties. We model the task as a binary labeling problem on a network, and use structured learning techniques to learn model parameters. We find that social-network metadata are useful in a variety of classification tasks, in many cases outperforming methods based on image content.
AN ADAPTIVE OPTICS SURVEY OF M6.0-M7.5 STARS: DISCOVERY OF THREE VERY LOW MASS BINARY SYSTEMS INCLUDING TWO PROBABLE HYADES MEMBERS

A survey of 30 nearby M6.0–M7.5 dwarfs with Ks 12 and 0>29 (3–10 AU) with similar mass ratios (q > 0:8, DKs 20 AU), very low mass (Mtot 3 AU. This binary frequency is less than the � 32% measured among early M dwarfs over the same separation range. Two of the low-mass binaries are probable Hyades open cluster members based on proper motions, cluster membership probabilities, radial velocities, and near-IR photometry. LP 415-20 has the distinction of being the tightest (3.6 AU) multiple system ever spatially resolved in the cluster, and the companions of LP 415-20 and LP 475-855 are among the least massive objects ever resolved in the Hyades, with estimated masses of 0:081 þ0:009 � 0:010 and 0:082 þ0:009 � 0:009 M� . Subject headings: binaries: general — instrumentation: adaptive optics — open clusters and associations: individual (Hyades) — stars: individual (LP 415-20, LP 475-855, 2MASSW J1750129+442404) — stars: low-mass, brown dwarfs
Ultrasound Technique for Prediction of Statistical Characteristics of Grid-Generated Turbulence

Ultrasonic technique can be used to determine some characteristics of turbulent flows. In this work, measurements of the difference in propagation times of ultrasonic waves along two paths are combined with the Kolmogorov (2/3)-power law to study characteristics of grid-generated turbulence. The paper focuses on ultrasonic measurements of turbulent flow using the travel-time technique. The theoretical analysis is based on the well-known Kolmogorov theory and supported by experimental data. The present research is of interest from two points of view. First, it demonstrates a non-invasive method of investigation of turbulence, and second, it furthers understanding of the effect of turbulence on sound propagation.
Instrumented assessment of FNS hand control during specific manipulation tasks

Describes tests that quantitatively assess the operation of FNS hand grasp neuroprostheses and the ability of spinal cord injury patients to use these systems to perform specific tasks simulating activities of daily living. An integrated measurement system monitors internal variables within the neuroprosthesis, the kinematics of the patient's arm and the grasped object, and interactions of the subject's hand with the object and the environment. Two tasks, drinking and eating, are broken down into sequential elemental states based on the measurements. The durations of each state, determined from the data, show that 1) patients using the neuroprosthesis take more time than normals to perform nearly all states of the two tasks, 2) the command control scheme has a large effect on the time a patient takes to pick up an object, 3) patients compensate for paralyzed forearm pronators by increasing shoulder abduction, and 4) patients use forces in the same range as normals during grasp. >
Comment on “The shape and composition of interstellar silicate grains”

In the paper entitled “The shape and composition of interstellar silicate grains” (AA Flynn 1994; Goodman & Whittet 1995; Martin 1995; Bradley et al. 1999). We agree that the match is imperfect, but given the statistical limitations of comparing less than a microgram of GEMS with the enormous mass of silicates in the ISM, this is not surprising.
Lewis Acid Adducts of [PCl2N]3

Reaction of aluminum trichloride or gallium trichloride with the extremely weak base hexachlorotriphosphazene gives adducts in which the group 13 element is bound to a phosphazene nitrogen atom. In solution, the adducts exhibit fluxional behavior. The phosphazene ring of the adducts is distorted into a slight chair conformation.
Brief and rare mental “breaks” keep you focused: Deactivation and reactivation of task goals preempt vigilance decrements

We newly propose that the vigilance decrement occurs because the cognitive control system fails to maintain active the goal of the vigilance task over prolonged periods of time (goal habituation). Further, we hypothesized that momentarily deactivating this goal (via a switch in tasks) would prevent the activation level of the vigilance goal from ever habituating. We asked observers to perform a visual vigilance task while maintaining digits in-memory. When observers retrieved the digits at the end of the vigilance task, their vigilance performance steeply declined over time. However, when observers were asked to sporadically recollect the digits during the vigilance task, the vigilance decrement was averted. Our results present a direct challenge to the pervasive view that vigilance decrements are due to a depletion of attentional resources and provide a tractable mechanism to prevent this insidious phenomenon in everyday life.
Copper-catalyzed trifluoromethylation of unactivated olefins.

The inclusion of fluorinated functional groups in small molecules has had a profound impact on the pharmaceutical, material, and agrochemical industries.[1, 2] In particular, the trifluoromethyl (CF3) substituent has emerged as an important functional group for the modulation of the physical properties in new pharmaceutical candidates as it has excellent metabolic stability, lipophilicity, and is electron-withdrawing in nature.[3] Myriad of fluorinated biologically active pharmaceutical compounds have been identified,[4] with an estimated 20% of drugs on the market containing fluorine.[1] On this basis, there has been a recent surge in the number of reports describing the formation of carbon–trifluoromethyl (C–CF3) bonds, demonstrating the continuing need for the development of efficient methods to incorporate these groups.
Penetration of liquid fingers into superheated fractured rock

[1] Water infiltrating down a fracture in unsaturated rock experiences complex fluid flow and heat transfer phenomena when entering above-boiling rock temperature regions. Such conditions are expected, for example, after emplacement of heat-generating nuclear waste in underground repositories. A new efficient semianalytical method is proposed in this paper that simulates the flow processes of infiltration events subject to vigorous boiling from the adjacent hot rock. It is assumed that liquid flow forms in localized preferential flow paths and that infiltration events are typically short in duration but large in magnitude relative to the average net infiltration. The new solution scheme is applied to several test cases studying sensitivity to a variety of input parameters. Sample simulations are performed for conditions representative of the potential nuclear waste repository at Yucca Mountain, Nevada. A characteristic parameter is introduced that provides a quick estimate of the relative significance of boiling at a given location of interest.
The First Catalytic, Diastereoselective, and Enantioselective Crossed‐Aldol Reactions of Aldehydes

The apotheosis of the aldol addition reaction is one of the most well-documented chapters of modern organic synthesis; the generality, versatility, and selectivity associated with this process have been the subject of countless reviews and authoritative summaries. Stimulated by the challenge posed by nature, a generation of synthetic organic chemists has constructed an impressive edifice of knowledge which constitutes insightful, elegant, and practical solutions to the structural and stereochemical problems presented by polypropionate-derived natural products. Yet, at this advanced vantage, it is remarkable that the most basic of aldol scaffold can be efficiently accomplished according to the Woerpel procedure employing the use of basic tBuOOH in DMF.[16] Several representative tetraols 12 were prepared in good yields with complete overall diastereoselectivity illustrating the generality of this strategy (Table 2). The occurrence of a polyol motif 12 in a number of bioactive natural products is noteworthy. Representative examples include the side chain portion of bacteriohopanoid.[17a] and the central macrolide segment of herbarumin I, a highly potent phytotoxic agent.[17b] In summary, we have demonstrated a highly enantioselective catalytic isomerization of silacyclopentene oxide, a pivotal point in our strategy for the stereoselective assembly of acyclic polyols. Development of an arsenal of new asymmetric processes utilizing cyclic silanes is currently in progress.
Do Going Concern Audit Reports Protect Auditors from Litigation? A Simultaneous Equations Approach

ABSTRACT: Audit researchers have a long-standing interest in understanding whether issuing a going concern report to financially stressed clients protects auditors from litigation. An endogeneity issue arises, in that litigation risk affects the going concern decision and the going concern decision impacts auditor litigation risk. Using a simultaneous equations approach, we find a significant positive association between auditors' ex ante litigation risk and going concern reporting. By applying simultaneous equations, we also find a significant negative association between going concern reporting and auditor litigation, suggesting that auditors deter lawsuits by issuing going concern reports to their financially stressed clients. Our research further provides a more rigorous analysis of the relation between going concern reporting and lawsuit outcomes in the form of auditor litigation dismissals, small settlement amounts, and large settlement amounts. Our results indicate that when auditors are named in ...
Learning by Communicating in Natural Language With Conversational Agents

Learning is facilitated by conversational interactions both with human tutors and with computer agents that simulate human tutoring and ideal pedagogical strategies. In this article, we describe some intelligent tutoring systems (e.g., AutoTutor) in which agents interact with students in natural language while being sensitive to their cognitive and emotional states. These systems include one-on-one tutorial dialogues, conversational trialogues in which two agents (a tutor and a “peer”) interact with a human student, and other conversational ensembles in which agents take on different roles. Tutorial conversations with agents have also been incorporated into educational games. These learning environments have been developed for different populations (elementary through high school students, college students, adults with reading difficulties) and different subjects spanning science, technology, engineering, mathematics, reading, writing, and reasoning. This article identifies some of the conversation patter...
The Bose Gas and Asymmetric Simple Exclusion Process on the Half-Line

In this paper we find explicit formulas for: (1) Green’s function for a system of one-dimensional bosons interacting via a delta-function potential with particles confined to the positive half-line; and (2) the transition probability for the one-dimensional asymmetric simple exclusion process (ASEP) with particles confined to the nonnegative integers. These are both for systems with a finite number of particles. The formulas are analogous to ones obtained earlier for the Bose gas and ASEP on the line and integers, respectively. We use coordinate Bethe Ansatz appropriately modified to account for confinement of the particles to the half-line. As in the earlier work, the proof for the ASEP is less straightforward than for the Bose gas.
Internal 26Al–26Mg isotope systematics of a Type B CAI: Remelting of refractory precursor solids

High precision SIMS 26 Al- 26 Mg isotope analyses were performed for a pristine Type B1 CAI Leoville 3535-1 on multiple mineral phases that include aluminum-rich zoned melilite mantle (Ak20-Ak60), magnesium-rich melilite (Ak70), fassaite, spinel and anorthite in the core. The data yield a well-defined internal isochron with an inferred initial 26 Al/ 27 Al ratio of (5.002 ± 0.065) � 10 � 5 , which is lower than those of bulk CAIs and pristine fine-grained CAIs. Assuming homogeneous dis- tribution of 26 Al in the early solar system, Leoville 3535-1 formed � 50 ka after the time corresponding to the bulk CAI iso- chron. One anorthite analysis near the grain boundary adjacent to melilite shows sub-lm-scale heterogeneous magnesium distribution, though the 26 Al- 26 Mg data plot on the isochron regression. Thus, the internal 26 Al- 26 Mg system of the CAI remained closed since the last melting event that crystallized anorthite. High precision magnesium isotope analyses of magnesium-rich minerals (fassaite, magnesium-rich melilite, and spinel) show a small amount of scatter from the regression line (� 0.1&) beyond analytical uncertainties. Most spinel and some fassa- ite data are systematically displaced below and above the regression line, respectively. It is likely that spinel remained unmelted at the time of the last melting event, while fassaite and anorthite crystallized from a partial melt. The regression line made by fassaite and anorthite data shows an initial 26 Al/ 27 Al ratio indistinguishable from that using all data. Mass dependent fractionation of magnesium isotopes in spinel is the same as those in melilite and fassaite (d 25 Mg � 5&), indicating that magnesium isotope fractionation, presumably from evaporative magnesium loss, predated the last melting event. Thus a majority of the CAI appears to have escaped magnesium isotope exchange with nebular gas during the last melting event, except for the outer rim of the melilite mantle that shows slightly lower d 25 Mg values. The 26 Al- 26 Mg systematics of this Leoville Type B CAI suggest it experienced a final melting event at � 50 ka after the initial Al-Mg fractionation event. This may correspond to melting during the active protostar stage (known as "Class I"), during which sporadic high temperature heating events repeatedly affected refractory solids in the solar nebula. 2012 Elsevier Ltd. All rights reserved.
Thermal parameter estimation using recursive identification

A novel method that converts a semiconductor transient thermal impedance curve (TTIC) into an equivalent thermal RC network model is presented. Thermal resistance (R) and thermal capacitance (C) parameters of the model are identified using manufacturer's data and offline recursive least square techniques. Relevant estimation theory concepts and the formulation of an appropriate model for the identification process are given. Model synthesis is illustrated using an isolated base power transistor module. The application of time decoupled theory for high order thermal models is outlined. Simulation of junction temperature responses using model and manufacturer TTICs are compared. Estimated parameter validity is further confirmed by parameter calculation obtained from module physical dimensions. >
The complexity of decentralized control of Markov decision processes

Planning for distributed agents with partial state information is considered from a decisiontheoretic perspective. We describe generalizations of both the MDP and POMDP models that allow for decentralized control. For even a small number of agents, the finite-horizon problems corresponding to both of our models are complete for nondeterministic exponential time. These complexity results illustrate a fundamental difference between centralized and decentralized control of Markov processes. In contrast to the MDP and POMDP problems, the problems we consider provably do not admit polynomialtime algorithms and most likely require doubly exponential time to solve in the worst case. We have thus provided mathematical evidence corresponding to the intuition that decentralized planning problems cannot easily be reduced to centralized problems and solved exactly using established techniques.
Engineering theories with z3

Modern Satisfiability Modulo Theories (SMT) solvers are fundamental to many program analysis, verification, design and testing tools. They are a good fit for the domain of software and hardware engineering because they support many domains that are commonly used by the tools. The meaning of domains are captured by theories that can be axiomatized or supported by efficient theory solvers. Nevertheless, not all domains are handled by all solvers and many domains and theories will never be native to any solver. We here explore different theories that extend Microsoft Research's SMT solver Z3's basic support. Some can be directly encoded or axiomatized, others make use of user theory plug-ins. Plug-ins are a powerful way for tools to supply their custom domains.
The boundary conditions of the heliosphere : photoionization models constrained by interstellar and in situ data

Context. The boundary conditions of the heliosphere are set by the ionization, density, and composition of inflowing interstellar matter. Aims. Our aim is to constrain the properties of the Local Interstellar Cloud (LIC) at the heliosphere, which requires radiative transfer ionization models. Methods. We modeled the background interstellar radiation field using observed stellar FUV and EUV emission and the diffuse soft X-ray background. We also modeled the emission from the boundary between the LIC and the hot Local Bubble plasma, assuming that the cloud is evaporating because of thermal conduction. We created a grid of models covering a plausible range of LIC and Local Bubble properties, and used the modeled radiation field as input to radiative transfer/thermal equilibrium calculations using the Cloudy code. Data from in situ observations of He 0 , pickup ions and anomalous cosmic rays in the heliosphere, as well as from – –
Micro-reactors for PET Tracer Labeling

Miniaturization of PET radiosynthesis devices (micro-reactors or microfluidic systems) is an emerging area that has the potential to deliver many advantages, such as more efficient use of hot-cell space for production of multiple radiotracers; use of less non-radioactive precursor for saving precious material and a reduced separation challenge; highly controlled, reproducible and reliable radiotracer production; and cheap, interchangeable, disposable and quality-assured radiochemistry processors. Several ‘proof of principle’ examples along with basics of micro-reactor flow control, mixing principle and design, and device fabrication are discussed in this chapter.
Enantiospecific total synthesis of (+)- and (–)-avarone and -avarol

Enantiopure avarol and its oxidized congener avarone are synthesized in both podal series from an optically pure Wieland–Miescher enone; preliminary results from biochemical studies are summarized.
RIEMANN-ROCH FOR QUOTIENTS AND TODD CLASSES OF SIMPLICIAL TORIC VARIETIES

Abstract In this paper we give an explicit formula for the Riemann-Roch map for singular schemes which are quotients of smooth schemes by diagonalizable groups. As an application we obtain a simple proof of a formula for the Todd class of a simplicial toric variety. An equivariant version of this formula was previously obtained for complete simplicial toric varieties by Brion and Vergne (Brion M. and Vergne M. ([1997]). An equivariant Riemann-Roch theorem for complete simplicial toric varieties. J. Reine. Agnew. Math.482:67–92) using different techniques. Dedicated to Steven L. Kleiman on the occasion of his 60th birthday.
Remittances and the Brain Drain : do more skilled migrants remit more?

In most destination countries, immigration policies are tilted more and more in favor of skilled individuals. Whether this shift hurts economic prospects in sending countries, as argued by the traditional brain drain literature, is somewhat controversial. The most recent literature focuses on the link between skilled outmigration and educational achievements in the home country. This article emphasizes a different channel. It considers the argument that skilled migrants raise economic welfare at home by sending a relatively larger flow of remittances. While skilled migrants typically earn more, and so might be expected to remit more, they are also likely to spend more time abroad and to reunite with their close family in the host country. These second two factors should be associated with a smaller propensity to remit. Thus, the sign of the impact of the brain drain on total remittances is an empirical question. A simple model has been developed showing that skilled migrants may indeed have a lower propensity to remit from a given flow of earnings. An empirical equation of remittances is estimated as a measure of the brain drain in developing countries using the Docquier and Marfouk (2004) data set. Evidence is found that the brain drain is associated with a smaller propensity to remit.
Feature Selection via Probabilistic Outputs

This paper investigates two feature-scoring criteria that make use of estimated class probabilities: one method proposed by Shen et al. (2008) and a complementary approach proposed below. We develop a theoretical framework to analyze each criterion and show that both estimate the spread (across all values of a given feature) of the probability that an example belongs to the positive class. Based on our analysis, we predict when each scoring technique will be advantageous over the other and give empirical results validating our predictions.
Adaptive dimension reduction for clustering high dimensional data

It is well-known that for high dimensional data clustering, standard algorithms such as EM and K-means are often trapped in a local minimum. Many initialization methods have been proposed to tackle this problem, with only limited success. In this paper we propose a new approach to resolve this problem by repeated dimension reductions such that K-means or EM are performed only in very low dimensions. Cluster membership is utilized as a bridge between the reduced dimensional subspace and the original space, providing flexibility and ease of implementation. Clustering analysis performed on highly overlapped Gaussians, DNA gene expression profiles and Internet newsgroups demonstrate the effectiveness of the proposed algorithm.
An Eulerian Model of Phytoplankton Photosynthetic Response in the Upper Mixed Layer

We combined an Eulerian model of an upper mixed layer forced by dynamic and convective processes with a responsive photoadaptation model of photosynthesis. Incident radiation was divided into photosynthetically active and inactive components. The model was initialized to simulate physical conditions in Lake Titicaca on August 12, 1982, but it applies equally well to oceanic conditions. The simulation provides the time course of water column temperature, phytoplankton photoinhibition, and relative carbon fixation of phytoplankton as depth contours for comparison with the field data. The predicted and observed temperature profiles generally agree; diurnal changes in specific humidity are required to more accurately specify heat loss. The predicted photoinhibition resembles the observed photosynthetic state of the natural community based on fluorescence, but the modeled recovery from photoinhibition is too rapid. This discrepancy also affects the comparison between predicted and observed bottle determination of carbon fixation. The biological formulations in the model provide approximate fits to field observations, but improved realism requires a biological initialization that is more specific to the natural phytoplankton community.
Automatic Robust Neurite Detection and Morphological Analysis of Neuronal Cell Cultures in High-content Screening

Cell-based high content screening (HCS) is becoming an important and increasingly favored approach in therapeutic drug discovery and functional genomics. In HCS, changes in cellular morphology and biomarker distributions provide an information-rich profile of cellular responses to experimental treatments such as small molecules or gene knockdown probes. One obstacle that currently exists with such cell-based assays is the availability of image processing algorithms that are capable of reliably and automatically analyzing large HCS image sets. HCS images of primary neuronal cell cultures are particularly challenging to analyze due to complex cellular morphology. Here we present a robust method for quantifying and statistically analyzing the morphology of neuronal cells in HCS images. The major advantages of our method over existing software lie in its capability to correct non-uniform illumination using the contrast-limited adaptive histogram equalization method; segment neuromeres using Gabor-wavelet texture analysis; and detect faint neurites by a novel phase-based neurite extraction algorithm that is invariant to changes in illumination and contrast and can accurately localize neurites. Our method was successfully applied to analyze a large HCS image set generated in a morphology screen for polyglutamine-mediated neuronal toxicity using primary neuronal cell cultures derived from embryos of a Drosophila Huntington’s Disease (HD) model.
Multinational Firms and the Structure of International Trade

This chapter reviews the state of the international trade literature on multinational firms. This literature addresses three main questions. First, why do some firms operate in more than one country while others do not? Second, what determines in which countries production facilities are located? Finally, why do firms own foreign facilities rather than simply contract with local producers or distributors? We organize our exposition of the trade literature on multinational firms around the workhorse monopolistic competition model with constant-elasticity-of-substitution (CES) preferences. On the theoretical side, we review alternative ways to introduce multinational activity into this unifying framework, illustrating some key mechanisms emphasized in the literature. On the empirical side, we discuss the key studies and provide updated empirical results and further robustness tests using new sources of data.
Long's equation in terrain following coordinates

Long's equation describes two dimensional strat- ified atmospheric flow over terrain which is represented by the geometry of the domain. The solutions of this equation over simple topography were investigated analytically and numerically by many authors. In this paper we derive a new terrain following formulation of this equation which incorpo- rates the terrain as part of the differential equation rather than the geometry of the domain. This new formulation enables us to compute analytically steady state gravity wave patterns over complex topography in some limiting cases of the pa- rameters that appear in this equation. Long's equation also provides the theoretical framework for the analysis of experimental data (Shutts, 1988, 1994; Jumper, 2005) under the assumption of shearless base flow. (An assumption which, in general, is not supported by the data; Humi, 2004b.) An extensive list of references appears in (Baines, 1995; Carmen, 2002; Yih, 1980). An analytic approach to the study of the solutions of this nonlinear equation was initiated recently by the current au- thor (Humi, 2004a, 2006, 2007). We showed that for a base flow without shear and under rather mild restrictions the non- linear terms in the equation can be simplified. We also iden- tified the "slow variable" that controls the nonlinear oscilla- tions in this equation. Using phase averaging approximation we derived for self similar solutions of this equation a for- mula for the attenuation of the stream function perturbation with height. This result is generically related to the presence of the nonlinear terms in Long's equation. The impact that
Some norm estimates for semimartingales

In this paper we introduce a new type of norms for semimartingales, under both linear and nonlinear expectations. Our norm is defined in the spirit of quasimartingales, and it characterizes square integrable semimartingales. This work is motivated by our study of zero-sum stochastic differential games, whose value process is conjectured to be a semimartingale under a class of probability measures. As a by product, we establish some a priori estimates for doubly reflected BSDEs without imposing the Mokobodski's condition directly.
Application of an equilibrium vaporization model to the ablation of chondritic and achondritic meteoroids

We modeled equilibrium vaporization of chondritic and achondritic materials using the MAGMA code. We calculated both instantaneous and integrated element abundances of Na, Mg, Ca, Al, Fe, Si, Ti, and K in chondritic and achondritic meteors. Our results are qualitatively consistent with observations of meteor spectra.