cssi/SciSciGPT-SciSciNet huggingface dataset:
Artificial metalloenzymes based on protein cavities: Exploring the effect of altering the metal ligand attachment position by site directed mutagenesis

Abstract In an effort to construct catalysts with enzyme-like properties, we are employing a small, cavity-containing protein as a scaffold for the attachment of catalytic groups. In earlier work we demonstrated that a phenanthroline ligand could be introduced into the cavity of the protein ALBP and used to catalyze ester hydrolysis. To examine the effect of positioning the phenanthroline catalyst at different locations wthin the protein cavity, three new constucts — Phen60, Phen72 and Phen104 — were prepared. Each new conjugate was characterized by UV/vis spectroscopy, fluorescence spectroscopy, guanidine hydrochloride denaturation, gel filtration chromatography, and CD spectroscopy to confirm the preparation of the desired contruct. Analysis of reactions containing Ala-OiPr showed that Phen60 catalyzed ester hydrolysis with less selectivity than ALBP-Phen while Phen72 promoted this same reaction with higher selectivity. Reactions with Tyr-OMe were catalyzed with higher selectivity by Phen60 and more rapidly by Phen104. These results demonstrate that both the rates and selectivities of hydrolysis reactions catalyzed by these constructs are dependent on the precise site of attachment of the metal ligand within the protein cavity.
Multipath live streaming via TCP: Scheme, performance and benefits

Motivated by the wide use of TCP for multimedia streaming in practice and the increasing availability of multipath between end hosts, we study multipath live streaming via TCP in this article. We first design a simple and practical TCP-based multipath streaming scheme, named Dynamic MPath-streaming (DMP-streaming), which dynamically distributes packets over multiple paths by implicitly inferring the available bandwidths on these paths. To allow systematic performance study, we develop an analytical model for DMP-streaming and validate the model using extensive ns simulation and Internet experiments. We explore the parameter space of this model and find that DMP-streaming generally provides satisfactory performance when the aggregate achievable TCP throughput is 1.6 times the video bitrate, when allowing a few seconds of startup delay. Last, we comment on the benefits of using multipath versus single path for TCP-based streaming.
High Magnetic Field Pulsars and Magnetars: A Unified Picture.

We propose a unified picture of high magnetic field radio pulsars and magnetars by arguing that they are all rotating high-field neutron stars but that their magnetic axes have different orientations with respect to their rotation axes. In strong magnetic fields where photon splitting suppresses pair creation near the surface, the high-field pulsars can have active inner accelerators while the anomalous X-ray pulsars cannot. This can account for the very different observed emission characteristics of the anomalous X-ray pulsar 1E 2259+586 and the high-field radio pulsar PSR J1814-1744. A predicted consequence of this picture is that radio pulsars having surface magnetic fields greater than about 2 × 1014 G should not exist.
A Remark on Contraction Semigroups on Banach Spaces

Let $X$ be a complex Banach space and let $J:X \to X^*$ be a duality section on $X$ (i.e. $\langle x,J(x)\rangle=\|J(x)\|\|x\|=\|J(x)\|^2=\|x\|^2$). For any unit vector $x$ and any ($C_0$) contraction semigroup $T=\{e^{tA}:t \geq 0\}$, Goldstein proved that if $X$ is a Hilbert space and if $|\langle T(t) x,J(x)\rangle| \to 1 $ as $t \to \infty$, then $x$ is an eigenvector of $A$ corresponding to a purely imaginary eigenvalue. In this article, we prove the similar result holds if $X$ is a strictly convex complex Banach space.
Co-stimulation of TLR4 and Dectin-1 Induces the Production of Inflammatory Cytokines but not TGF-β for Th17 Cell Differentiation

Collaboration of TLR and non-TLR pathways in innate immune cells, which acts in concert for the induction of inflammatory cytokines, can mount a specific adaptive immune response tailored to a pathogen. Here, we show that murine DC produced increased IL-23 and IL-6 when they were treated with LPS together with curdlan that activates TLR4 and dectin-1, respectively. We also found that the induction of the inflammatory cytokine production by LPS and curdlan requires activation of IKK. However, the same treatment did not induce DC to produce a sufficient amount of TGF-β. As a result, the conditioned media from DC treated with LPS and curdlan was not able to direct CD4(+) T cells to Th17 cells. Addition of TGF-β but not IL-6 or IL-1β was able to promote IL-17 production from CD4(+) T cells. Our results showed that although signaling mediated by LPS together with curdlan is a potent stimulator of DC to secrete many pro-inflammatory cytokines, TGF-β production is a limiting factor for promoting Th17 immunity.
Proper Motions of OH Masers and Magnetic Fields in Massive Star-forming Regions

We present data of proper motions of OH masers in the massive star-forming regions ON 1, K3-50, and W51 Main/South. OH maser motions in ON 1 are consistent with expansion at approximately 5 km s-1, likely tracing the expanding ultracompact H II region. Motions in K3-50 are faster and may be indicating the final stages of OH maser emission in the source, before the OH masers turn off as the H II region transitions from the ultracompact to the compact phase. W51 South shows indications of aspherical expansion, while motions in W51 Main are more difficult to interpret. Nevertheless, it appears that the relative projected separation between W51 Main and W51 South is decreasing, corresponding to an estimate of enclosed mass of at least 1500 M?, consistent with estimates derived from millimeter-wavelength dust emission. We confirm the ~20 mG magnetic fields previously seen in W51 Main, which may represent the upper end of the density range allowable for 1665 MHz maser emission. Magnetic field strengths and directions, obtained from Zeeman splitting, in each source are consistent with values obtained in the first epoch 4-9 yr ago.
Comparison of Three Empirical Models of Airport Congestion Pricing

Abstract We compare three empirical models of airport congestion pricing: a standard peak-load-pricing model with econometrically estimated demand and delay functions (Morrison [ 7 ], Morrison and Winston [ 8 ]); a deterministic bottleneck model with traffic adjusting intertemporally to congestion prices (Vickrey [ 9 ], Arnott et al. [ 2 ]); and a bottleneck model with time-dependent stochastic queuing (Daniel [ 4 ]). When implemented using Daniel's airport traffic data, the models produce similar traffic patterns under weight-based pricing, but differ significantly under congestion pricing. We conclude that structural modeling of stochastic traffic, queues, and intertemporal substitution is necessary to produce realistic responses of traffic patterns to congestion pricing.
Engaging faculty in technology for teaching and research

As computer technology continues to develop at an unprecedented rate and costs for hardware decrease, its diffusion in higher education is growing dramatically. According to the National Center for Education Statistics, the number of students using computers in the first through fourth years of college increased from 39.2 percent in 1989 to 55.2 percent in October 1993. 1 Computers are everywhere on campus-in classrooms, labs, dorms, and offices. This widespread availability of technology in higher education has raised the hopes for radical changes and improvements in the teaching and learning process. While students have eagerly embraced technology, using computers as tools for communication, composition, and research, faculty, on the other hand, have used it much less in their work. Researchers speculate that one reason might be that faculty have experienced little or no computer training.2 This phenomenon has created a unique challenge for those of us who train computer users. We must nurture and expand the skills of computer savvy students. At the same time, we must also educate faculty about the value of technology in meeting their teaching goals and objectives.
Applications of state estimation in aircraft flight-data analysis

This paper traces the evolution of the use of state estimation in the analysis of aircraft flight data and discusses some recent applications associated with airline turbulence upsets and high-angle-of-attack flight tests. A unifying mathematical framework for state estimation is reviewed, and several examples are shown that illustrate a general approach for estimating variables that are difficult to measure. It is hoped that the diversity of the applications discussed and the examples presented will make the flight-data analyst mindful of the potential advantages of using state estimation methods.
Egocentric Categorization and Product Judgment: Seeing Your Traits in What You Own (and Their Opposite in What You Don’t)

Previous research uses categorization principles to analyze the interplay between individuals and groups. The present research uniquely employs categorization principles to analyze the interplay between individuals and products. It proposes that consumers classify owned (but not unowned) products as integral to their personal self (experiment 1). Consequently, consumers judge product traits (e.g., masculinity) as consistent with their own traits (assimilation) if they own the product, but as inconsistent with their own traits (contrast) if they interact with the product but do not own it, even when owning the product is nondiagnostic of its properties (e.g., following random ownership assignment; experiments 2–4). For example, less creative consumers who enter a drawing for an iPhone may judge it as less creative (assimilation) if they win the product, but as more creative (contrast) if they do not win the product. Moderators of these effects are identified, and their theoretical and substantive implicati...
Instrumental Variable Estimation of a Spatial Autoregressive Panel Model with Random Effects

This paper extends the instrumental variable estimators of Kelejian and Prucha (1998) and Lee (2003) proposed for the cross-sectional spatial autoregressive model to the random effects spatial autoregressive panel data model. It also suggests an extension of the Baltagi (1981) error component 2SLS estimator to this spatial panel model.
The Impact of Inflation on ROE, Growth and Stock Prices

Abstract Using the constant growth dividend discount model (DDM), it can be shown that the critical factor which determines whether common stocks will be able to be an inflation hedge is the growth rate of dividends. In turn, the growth of dividends is mainly impacted by the aggregate return on equity (ROE). Using the DuPont formula, it is clear that the main variable that drives the aggregate ROE in an inflationary environment is the profit margin. Following from this background, this article updates and extends an earlier analysis that involves an analysis of ROE and its components for the 40-year period 1956–1995. The analysis demonstrates that the aggregate ROE is currently at about the same level as in the 1960's, but the components have changed, that is, there has been a decline in total asset turnover and profit margin, but a significant increase in financial leverage that has compensated for the declines in turnover and profit margin. It is further shown that there have been periods of high and low inflation since 1956, and the negative impact of inflation of the implied growth rate is confirmed, which helps explain why investigators find consistent empirical results that common stocks are poor inflation hedges.
TeV physics and the Planck scale

Supersymmetry is one of the best motivated possibilities for new physics at the TeV scale. However, both concrete string constructions and phenomenological considerations suggest the possibility that the physics at the TeV scale could be more complicated than the minimal supersymmetric standard model (MSSM), e.g. due to extended gauge symmetries, new vector-like supermultiplets with non-standard SU(2)× U(1) assignments, and extended Higgs sectors. We briefly comment on some of these possibilities, and discuss in more detail the class of extensions of the MSSM involving an additional standard model singlet field. The latter provides a solution to the μ problem, and allows significant modifications of the MSSM in the Higgs and neutralino sectors, with important consequences for collider physics, cold dark matter, and electroweak baryogenesis.
THE X-RAY POWER SPECTRAL DENSITY FUNCTION OF THE SEYFERT ACTIVE GALACTIC NUCLEUS NGC 7469

We present the broadband X-ray power spectral density (PSD) function of the X-ray-luminous Seyfert 1.2 NGC 7469, measured from Rossi X-ray Timing Explorer monitoring data and two XMM-Newton observations. We find significant evidence for a turnover in the 2-10 keV PSD at a temporal frequency of 2.0{sup +3.0}{sub -0.8} x 10{sup -6} Hz or 1.0{sup +3.0}{sub -0.6} x 10{sup -6} Hz, depending on the exact form of the break (sharply broken or slowly bending power law, respectively). The 'surrogate' Monte Carlo method of Press et al. was used to map out the probability distributions of PSD model parameters and obtain reliable uncertainties (68% confidence limits quoted here). The corresponding break timescale of 5.8 {+-} 3.5 days or 11.6{sup +17.5}{sub -8.7} days, respectively, is consistent with the empirical relation between PSD break timescale, black hole mass, and bolometric luminosity of McHardy et al. Compared to the 2-10 keV PSD, the 10-20 keV PSD has a much flatter shape at high temporal frequencies, and no PSD break is significantly detected, suggesting an energy-dependent evolution not unlike that exhibited by several Galactic black hole systems.
Pd-Catalyzed Cross-Coupling Reactions of Amides and Aryl Mesylates

A catalyst, based on a biarylphosphine ligand, for the Pd-catalyzed cross-coupling reactions of amides and aryl mesylates is described. This system allows an array of aryl and heteroaryl mesylates to be transformed into the corresponding N-aryl amides in moderate to excellent yields.
Quasiconvex analysis of backtracking algorithms

We consider a class of multivariate recurrences frequently arising in the worst case analysis of Davis-Putnam-style exponential time backtracking algorithms for NP-hard problems. We describe a technique for proving asymptotic upper bounds on these recurrences, by using a suitable weight function to reduce the problem to that of solving univariate linear recurrences; show how to use quasiconvex programming to determine the weight function yielding the smallest upper bound; and prove that the resulting upper bounds are within a polynomial factor of the true asymptotics of the recurrence. We develop and implement a multiple-gradient descent algorithm for the resulting quasiconvex programs, using a real-number arithmetic package for guaranteed accuracy of the computed worst case time bounds.
Pervaporation, perstillation and percrystallization

Abstract 1. (1) Collodion and parchment membrane containers permit water to evaporate through the walls as though no membrane were present. This phenomenon is called pervaporation. 2. (2) Distillation by means of pervaporation is called perstillation, and can be conducted at ordinary atmospheric pressure with low temperatures as well as with vaccum. 3. (3) When a dialyzable constituent of a liquid within these containers reaches saturation, crystallization usually takes place on the outside. This phenomenon is called percrystallization. 4. (4) A number of experiments are described which show the possible uses of these phenomena in the arts and sciences. The theoretical considerations of the phenomena are briefly discussed.
Gravitational scattering in the c = 1 matrix model

Abstract The c =1 matrix model is equivalent to (1 + 1)-dimensional string theory. However, the tachyon self-interaction in the former is local, while in the latter it is nonlocal due to the gravitational, dilaton and higher string fields. By studying scattering of classical pulses we show that the appropriate nonlocal field redefinition converts the local matrix model interaction into the expected string form. In particular, we see how the asymptotic behavior of the gravitational field appears in the scattering.
Defect chemistry in layered transition-metal oxides from screened hybrid density functional calculations

We report a comprehensive first-principles study of the thermodynamics and transport of intrinsic point defects in layered oxide cathode materials LiMO2 (M = Co, Ni), using density-functional theory and the Heyd–Scuseria–Ernzerhof screened hybrid functional. We find that LiCoO2 has a complex defect chemistry; different electronic and ionic defects can exist under different synthesis conditions, and LiCoO2 samples free of cobalt antisite defects can be made under Li-excess (Co-deficient) environments. A defect model for lithium over-stoichiometric LiCoO2 is also proposed, which involves negatively charged lithium antisites and positively charged small (hole) polarons. In LiNiO2, a certain amount of Ni3+ ions undergo charge disproportionation and the concentration of nickel ions in the lithium layers is high. Tuning the synthesis conditions may reduce the nickel antisites but would not remove the charge disproportionation. In addition, we find that LiMO2 cannot be doped n- or p-type; the electronic conduction occurs via hopping of small polarons and the ionic conduction occurs via migration of lithium vacancies, either through a monovacancy or divacancy mechanism, depending on the vacancy concentration.
Wavelength-Dependent Photochemistry of 4-Methoxybicyclo[3.1.0]hexenones†

Wavelength-dependent photochemistry of a series of 4-methoxybicyclo[3.1.0]hexenones is mechanistically investigated. Upon excitation of the symmetry-forbidden S1 n→π* state, photoisomerization is exclusively observed. By comparison of the direct and sensitized quantum yields for this particular process, the T1 π→π* state, which is populated via efficient intersystem crossing as shown by phosphorescence experiments, is proven to be the reactive state. A pathway via external cyclopropane bond cleavage followed by racemization of the formed triplet biradicals reasonably accounts for the observed photostationarity. Excitation of the electric dipole allowed S2 π→π* state initiates phenol formation. The T2 n→π* state, which could not be sensitized, gives a type-B oxyallyl zwitterion via internal cleavage as could be shown by intermolecular as well as intramolecular trapping experiments. The observed data are in good agreement with computational studies.
Modular invariants of N = 2 supersymmetric SU (1, 1) models

Abstract We study the modular invariance of N = 2 superconformal SU (1, 1) models. By decomposing the characters of the Kazama-Suzuki model SU (3) ( SU (2) × U (1)) into an infinite sum of the characters of ( SU (1,1) U (1) ) × U (1) we construct modular invariant partition functions of ( SU (1,1) U (1) ) × U (1) .
An evaluation of Java for numerical computing

This paper describes the design and implementation of high performance numerical software in Java. Our primary goals are to characterize the performance of object-oriented numerical software written in Java and to investigate whether Java is a suitable language for such endeavors. We have implemented JLAPACK, a subset of the LAPACK library in Java. LAPACK is a high-performance Fortran 77 library used to solve common linear algebra problems. JLAPACK is an object-oriented library, using encapsulation, inheritance, and exception handling. It performs within a factor of four of the optimized Fortran version for certain platforms and test cases. When used with the native BLAS library, JLAPACK performs comparably with the Fortran version using the native BLAS library. We conclude that high-performance numerical software could be written in Java if a handful of concerns about language features and compilation strategies are adequately addressed.
The Political Roots of Executive Clemency

It is widespread conventional wisdom that presidential pardons—the only way for offenders to remove or eliminate all disabilities that arise from a federal or military offense—are political. We move beyond this belief and assess five broad ways that federal pardons may be systematically influenced by the policy agendas present in a separated powers system. We model the aggregate dispensation of clemency appeals (requests for pardons) using Prais-Winsten regression and find that the probability of denials for executive clemency reflects the president’s own agenda and ideological position, congressional attention to criminal justice issues, and the homicide rate. In sum, both policy signals and the political processes they signify permeate the presidential pardons process.
Landau Levels, Magnetic Fields and Holographic Fermi Liquids

We consider further a probe fermion in a dyonic black hole background in anti-de Sitter spacetime, at zero temperature, comparing and contrasting two distinct classes of solution that have previously appeared in the literature. Each class has members labeled by an integer n, corresponding to the nth Landau level for the fermion. Our interest is in the study of the spectral function of the fermion, interpreting poles in it as indicative of quasiparticles associated with the edge of a Fermi surface in the holographically dual strongly coupled theory in a background magnetic field H at finite chemical potential. Using both analytical and numerical methods, we explicitly show how one class of solutions naturally leads to an infinite family of quasiparticle peaks, signaling the presence of a Fermi surface for each level n. We present some of the properties of these peaks, which fall into a well-behaved pattern at large n, extracting the scaling of Fermi energy with n and H, as well as the dispersion of the quasiparticles.
Temperature dependence of DNA persistence length

We have determined the temperature dependence of DNA persistence length, a, using two different methods. The first approach was based on measuring the j-factors of short DNA fragments at various temperatures. Fitting the measured j-factors by the theoretical equation allowed us to obtain the values of a for temperatures between 5°C and 42°C. The second approach was based on measuring the equilibrium distribution of the linking number between the strands of circular DNA at different temperatures. The major contribution into the distribution variance comes from the fluctuations of DNA writhe in the nicked circular molecules which are specified by the value of a. The computation-based analysis of the measured variances was used to obtain the values of a for temperatures up to 60°C. We found a good agreement between the results obtained by these two methods. Our data show that DNA persistence length strongly depends on temperature and accounting for this dependence is important in quantitative comparison between experimental results obtained at different temperatures.
Targeting microRNAs in obesity

Obesity is a serious health problem worldwide associated with an increased risk of life-threatening diseases such as type 2 diabetes, atherosclerosis, and certain types of cancer. Fundamental for the development of novel therapeutics for obesity and its associated metabolic syndromes is an understanding of the regulation of fat cell development. Recent computational and experimental studies have shown that microRNAs (miRNAs) play a role in metabolic tissue development, lipid metabolism and glucose homeostasis. In addition, many miRNAs are dysregulated in metabolic tissues from obese animals and humans, which potentially contributes to the pathogenesis of obesity-associated complications. In this review we summarize the current state of understanding of the roles of miRNAs in metabolic tissues under normal development and obese conditions, and discuss the potential use of miRNAs as therapeutic targets.
Automated Synthesis of a Protected N-Linked Glycoprotein Core Pentasaccharide

Described is the first automated solid-phase synthesis of the core N-linked pentasaccharide, common to all N-linked glycoproteins via stepwise assembly from mono- and disaccharide building blocks. The challenging β-mannosidic linkage was incorporated by the inclusion of a disaccharide trichloroacetimidate. This automated synthesis provides rapid access to an oligosaccharide common to an entire class of glycoconjugates.
Multi-attribute Regret-Based Dynamic Pricing

In this paper, we consider the problem of dynamic pricing by a set of competing sellers in an information economy where buyers differentiate products along multiple attributes, and buyer preferences can change temporally. Previous research in this area has either focused on dynamic pricing along a limited number of (e.g. binary) attributes, or, assumes that each seller has access to private information such as preference distribution of buyers, and profit/price information of other sellers. However, in real information markets, private information about buyers and sellers cannot be assumed to be available a priori. Moreover, due to the competition between sellers, each seller faces a tradeoff between accuracy and rapidity of the pricing mechanism. In this paper, we describe a multi-attribute dynamic pricing algorithm based on minimax regret that can be used by a seller’s agent called a pricebot, to maximize the seller’s utility. Our simulation results show that the minimax regret based dynamic pricing algorithm performs significantly better than other algorithms for rapidly and dynamically tracking consumer attributes without using any private information from either buyers or sellers.
Alfabetización mediática como método para fomentar la participación cívica

Los cambios en la tecnologia han posibilitado un nuevo tipo de ciudadania participativa; los ciudadanos utilizan blogs, correos, tweets, principalmente para crear e interactuar con otros. Este articulo explora la interseccion de los medios de comunicacion y la alfabetizacion mediatica y su relacion con la participacion ciudadana, mediante el analisis de tres programas especificos que se llevan a cabo en Estados Unidos. Estos proyectos son «Voces para los ninos» (Powerful Voices for Kids), «Academia de Salzburgo en Comunicacion y Cambio Social» (The Salzburg Academy on Media and Social Change) y «Educando a jovenes en Red como ciudadanos globales, alfabetizados mediaticamente en la era digital» (Cultivating the NetGeneration of Youth as Global Citizens and Media Literate Leaders in a Digital Age). En ellos educadores y alumnos de escuelas de Estados Unidos y Africa tienen encuentros virtuales y presenciales para explorar metodos colaborativos, utilizando los medios para construir puentes de entendimiento. A traves del analisis de cada programa y las entrevistas personales con algunos de sus directores, se presentan metodos que consiguen un buen desarrollo de proyectos de alfabetizacion mediatica focalizados en la participacion democratica, incluyendo, a su vez, la necesidad de crear actividades que reflejen el respeto hacia el interes de los estudiantes en la cultura popular, la voluntad de los educadores para superar los prejuicios sobre su falta de interes en temas de actualidad, el reconocimiento de la tecnologia como un medio y no como un fin en si misma, y la utilizacion de un equipo de apoyo para el profesorado.
Fabrication and characterization of superconducting circuit QED devices for quantum computation

We present fabrication and characterization procedures of devices for circuit quantum electrodynamics (cQED). We have made 3-GHz cavities with quality factors in the range 10/sup 4/-10/sup 6/, which allow access to the strong coupling regime of cQED. The cavities are transmission line resonators made by photolithography. They are coupled to the input and output ports via gap capacitors. An Al-based Cooper pair box is made by e-beam lithography and Dolan bridge double-angle evaporation in superconducting resonators with high quality factor. An important issue is to characterize the quality factor of the resonators. We present an RF-characterization of superconducting resonators as a function of temperature and magnetic field. We have realized different versions of the system with different box-cavity couplings by using different dielectrics and by changing the box geometry. Moreover, the cQED approach can be used as a diagnostic tool of qubit internal losses.
Stereocontrol in the EtAlCl2-Induced cyclization of chiral γ, δ-unsaturated methyl ketones to form cyclopentanones

EtAlCl2-induced cyclization of chiral γ,δ-unsaturated ketones 11c and 17b takes place mainly from the expected face. The selectivity is modest for 11c (60:40) in which the large substituent is a pr...
Deformations of Coxeter Hyperplane Arrangements

We investigate several hyperplane arrangements that can be viewed as deformations of Coxeter arrangements. In particular, we prove a conjecture of Linial and Stanley that the number of regions of the arrangement xi?xj=1, 1?i
Hundreds of Milky Way Satellites? Luminosity Bias in the Satellite Luminosity Function

We correct the observed Milky Way satellite luminosity function for luminosity bias using published completeness limits for the Sloan Digital Sky Survey DR5. Assuming that the spatial distribution of Milky Way satellites tracks the subhalos found in the Via Lactea ΛCDM N-body simulation, we show that there should be between ~300 and ~600 satellites within 400 kpc of the Sun that are brighter than the faintest known dwarf galaxies and that there may be as many as ~1000, depending on assumptions. By taking into account completeness limits, we show that the radial distribution of known Milky Way dwarfs is consistent with our assumption that the full satellite population tracks that of subhalos. These results alleviate the primary worries associated with the so-called missing satellites problem in CDM. We show that future, deep wide-field surveys such as SkyMapper, the Dark Energy Survey (DES), PanSTARRS, and the Large Synoptic Survey Telescope (LSST) will deliver a complete census of ultrafaint dwarf satellites out to the Milky Way virial radius, offer new limits on the free-streaming scale of dark matter, and provide unprecedented constraints on the low-luminosity threshold of galaxy formation.
Theories of Statistical Discrimination and Affirmative Action: A Survey

Abstract This chapter surveys the theoretical literature on statistical discrimination and affirmative action. This literature suggests different explanations for the existence and persistence of group inequality. This survey highlights such differences and describes in these contexts the effects of color-sighted and color-blind affirmative action policies, and the efficiency implications of discriminatory outcomes. JEL Classification Codes: J150, J160, J700, J780
Boolean satisfiability with transitivity constraints

We consider a variant of the Boolean satisfiability problem where a subset e of the propositional variables appearing in formula Fsat encode a symmetric, transitive, binary relation over N elements. Each of these relational variables, ei,j, for 1 ≤ i
Pulsed Laser Activated Cell Sorting with Three Dimensional Sheathless Inertial Focusing

The fluorescence-activated cell sorter (FACS) is a powerful tool for high-throughput single cell analysis in both fundamental biomedical research and clinical applications.[1–9] Conventional FACS focuses a cell suspension into a single stream with three-dimensional sheath flows through a small nozzle. Droplets leaving the nozzle are selectively and electrostatically charged and sorted based on the fluorescence of an encapsulated cell at a typical throughput lower than 25000 cells s−1.[4,5,10] This throughput facilitates both research and clinical applications, such as isolating sub-populations of immune cells for molecular analysis and sorting of circulating tumor cells (CTCs) from blood samples in a reasonable time.[11] However, current aerosol based FACS suffers several drawbacks. One shortcoming is the potential for sample contamination, which can generate a personal safety issue for FACS operators due to infectious aerosols.[12] Perhaps more importantly, aerosol-based FACS does not provide a convenient interface for integration with upstream pre-sort or downstream post-sort sample preparation or analysis modules, especially with many of the novel microfluidic modules developed over the past decade.
The organization of responsiveness: innovation and recovery in the trading rooms of Lower Manhattan

What is the organizational basis of responsiveness under conditions of crisis? In this essay we examine a trading room that was damaged in the September 11th attack on the World Trade Center. What did the crisis reveal about the social practices and the technological tools of trading? Drawing on ethnographic field research prior to September 11th, we show how the heterarchical (as opposed to hierarchical) organization of the trading room contributed to innovation on an ongoing basis. Drawing on our subsequent observations in the relocated trading room and focus group discussions with executives in other World Trade Center financial firms, we show that similarly heterarchical features contributed to innovation in response to crisis. Under conditions of radical uncertainty, one cannot know in advance what resources one will need, or even know in advance what might be a resource. Laterally distributed intelligence and a tolerance of multiple registers of valuation and interaction provide generative structures of resourcefulness where the replicative redundancy of contingency planning confronts its limits. We conclude with a brief discussion of the implications of our findings on innovation, location and responsiveness for the changing urban geography of finance and the redevelopment of Lower Manhattan.
Matrices of unitary moments

We investigate certain matrices composed of mixed, second-order moments of unitaries. The unitaries are taken from $C^*$-algebras with moments taken with respect to traces, or, alternatively, from matrix algebras with the usual trace. These sets are of interest in light of a theorem of E. Kirchberg about Connes' embedding problem.
Ultrasound screening for fetal aneuploidy using soft markers in the overweight and obese gravida

Objective To determine the completion rate of ultrasound surveys for aneuploidy markers by maternal body mass index (BMI). Methods A retrospective review of ultrasounds on midtrimester singleton pregnancies was performed. Subjects were grouped as normal, overweight (BMI 25–29.9 kg/m2), and obese: class I (30–34.9 kg/m2), class II (35–39.9 kg/m2), and class III (≥ 40 kg/m2). Examinations with visualization of at least seven of eight markers were considered complete. Results Of 14 353 ultrasounds reviewed, 5690 patients were eligible: 43% normal, 29% overweight, 27% obese. Completion rates differed significantly between groups (64% normal, 64% overweight, 61% class I, 55% class II, 47% class III, p < 0.001). The screen positive rates (≥1 marker) differed significantly overall (16% normal, 13% overweight, 15% class I, 12% class II, 10% class III, p < 0.02), but not for complete examinations (p = 0.42). Conclusions Since completion rates for ultrasound aneuploidy screening are inversely related to maternal obesity, obese women are underscreened. Copyright © 2010 John Wiley & Sons, Ltd.
An integrated patch-clamp amplifier in silicon-on-sapphire CMOS

We fabricated an integrated patch-clamp amplifier capable of recording from pico- to tens of micro-amperes of current. The high-dynamic range of seven decades and the pico-ampere sensitivity of the instrument was designed for whole-cell patch-clamp recordings. The prototype was fabricated on a 0.5/spl mu/m silicon-on-sapphire process. The device employs an integrating headstage with a frequency-modulated output pulse ranging from 3Hz to 10MHz. A digital interface produces a 16bit output conversion of the input currents. We report on electrical measurements from the fabricated device, and measurements conducted on cells in a typical patch-clamp experiment.
On Learning Discrete Graphical Models using Greedy Methods

In this paper, we address the problem of learning the structure of a pairwise graphical model from samples in a high-dimensional setting. Our first main result studies the sparsistency, or consistency in sparsity pattern recovery, properties of a forward-backward greedy algorithm as applied to general statistical models. As a special case, we then apply this algorithm to learn the structure of a discrete graphical model via neighborhood estimation. As a corollary of our general result, we derive sufficient conditions on the number of samples n, the maximum node-degree d and the problem size p, as well as other conditions on the model parameters, so that the algorithm recovers all the edges with high probability. Our result guarantees graph selection for samples scaling as n = Ω(d2 log(p)), in contrast to existing convex-optimization based algorithms that require a sample complexity of Ω(d3 log(p)). Further, the greedy algorithm only requires a restricted strong convexity condition which is typically milder than irrepresentability assumptions. We corroborate these results using numerical simulations at the end.
The External Debt Problem of Sub-Saharan Africa

The massive external debt burden of sub-Saharan Africa has gained widespread attention as a serious policy issue during the past few years. This paper reviews recent trends in the debt levels and economic performance of sub-Saharan countries and assesses a number of proposals for reducing their external debt service obligations. There is also a discussion of the modalities of various debt relief proposals that have been advanced.
ParNes: a rapidly convergent algorithm for accurate recovery of sparse and approximately sparse signals

In this article, we propose an algorithm, nesta-lasso, for the lasso problem, i.e., an underdetermined linear least-squares problem with a 1-norm constraint on the solution. We prove under the assumption of the restricted isometry property (rip) and a sparsity condition on the solution, that nesta-lasso is guaranteed to be almost always locally linearly convergent. As in the case of the algorithm nesta, proposed by Becker, Bobin, and Candes, we rely on Nesterov's accelerated proximal gradient method, which takes $O(\sqrt {1/\varepsilon })$ iterations to come within $\varepsilon > 0$ of the optimal value. We introduce a modification to Nesterov's method that regularly updates the prox-center in a provably optimal manner. The aforementioned linear convergence is in part due to this modification. In the second part of this article, we attempt to solve the basis pursuit denoising (bpdn) problem (i.e., approximating the minimum 1-norm solution to an underdetermined least squares problem) by using nesta-lasso in conjunction with the Pareto root-finding method employed by van den Berg and Friedlander in their spgl1 solver. The resulting algorithm is called parnes. We provide numerical evidence to show that it is comparable to currently available solvers.
A utility-theoretic approach to privacy in online services

Online offerings such as web search, news portals, and e-commerce applications face the challenge of providing high-quality service to a large, heterogeneous user base. Recent efforts have highlighted the potential to improve performance by introducing methods to personalize services based on special knowledge about users and their context. For example, a user's demographics, location, and past search and browsing may be useful in enhancing the results offered in response to web search queries. However, reasonable concerns about privacy by both users, providers, and government agencies acting on behalf of citizens, may limit access by services to such information. We introduce and explore an economics of privacy in personalization, where people can opt to share personal information, in a standing or on-demand manner, in return for expected enhancements in the quality of an online service. We focus on the example of web search and formulate realistic objective functions for search efficacy and privacy. We demonstrate how we can find a provably near-optimal optimization of the utility-privacy tradeoff in an efficient manner. We evaluate our methodology on data drawn from a log of the search activity of volunteer participants. We separately assess users preferences about privacy and utility via a large-scale survey, aimed at eliciting preferences about peoples willingness to trade the sharing of personal data in returns for gains in search efficiency. We show that a significant level of personalization can be achieved using a relatively small amount of information about users.
Q-systems as cluster algebras

Q-systems first appeared in the analysis of the Bethe equations for the XXX model and generalized Heisenberg spin chains (Kirillov and Reshetikhin 1987 Zap. Nauchn. Sem. Leningr. Otd. Mat. Inst. Steklov. 160 211–21, 301). Such systems are known to exist for any simple Lie algebra and many other Kac–Moody algebras. We formulate the Q-system associated with any simple, simply-laced Lie algebras in the language of cluster algebras (Fomin and Zelevinsky 2002 J. Am. Math. Soc. 15 497–529), and discuss the relation of the polynomiality property of the solutions of the Q-system in the initial variables, which follows from the representation–theoretical interpretation, to the Laurent phenomenon in cluster algebras (Fomin and Zelevinsky 2002 Adv. Appl. Math. 28 119–44).
Direct evidence that the VEGF-specific antibody bevacizumab has antivascular effects in human rectal cancer

The effects of vascular endothelial growth factor (VEGF) blockade on the vascular biology of human tumors are not known. Here we show here that a single infusion of the VEGF-specific antibody bevacizumab decreases tumor perfusion, vascular volume, microvascular density, interstitial fluid pressure and the number of viable, circulating endothelial and progenitor cells, and increases the fraction of vessels with pericyte coverage in rectal carcinoma patients. These data indicate that VEGF blockade has a direct and rapid antivascular effect in human tumors.
Optical Properties and Electronic Structure of Mantle Silicates

Summary Unpolarized specular reflectance spectra at near-normal incidence were measured in the silicates olivine, pyroxene, spinel and Al-garnet in the photon energy range 4-14eV at 300"K, and the optical and dielectric functions were obtained from the reflectance by Kramers-Kronig analysis. The spectra indicate that these minerals, with a variety of divalent cation substitutions, have wide valence and conduction bands separated by an energy gap (EJ of 7.5-9.5eV that is marked by a prominent absorption peak of an exciton associated with this gap. EB increases with the ratio x = Mg/(Mg+Fe+Mn+Ni+Ca) and in olivine it varies from 7.8 eV in fayalite to 8.8 eV in forsterite. For a given x, Eg increases in the order spinel, olivine, pyroxene, garnet over a range of about 1-5 eV. While the pure Mg-silicates are transparent at photon energies below the exciton peak, transition metal substitutions result in strong absorption beginning about 1-2 eV below Eg, presumably due to electronic transitions between the wide bands and d states localized on the transition metal cations. The large magnitude of Eg rules out the possibility that electronic band conduction due to valence-conduction band excitations is an important conduction mechanism in mantle silicates.
Roadcast: a popularity aware content sharing scheme in VANETs

Content sharing through vehicle-to-vehicle communication can help people find their interested content on the road. In VANETs, due to limited contact duration time and the unreliable wireless connection, a vehicle can only get the useful data when it meets the vehicle which has the exactly matching data. However, the probability of such cases is very low. To improve the performance of content sharing in intermittently connected VANETs, we propose a novel P2P content sharing scheme called Roadcast. Roadcast relaxes user's query requirement a little bit so that each user can have more chances to get the requested content quickly. Furthermore, Roadcast ensures popular data is more likely to be shared with other vehicles so that the performance of overall query delay can be improved. Roadcast consists of two components called popularity aware content retrieval and popularity aware data replacement. The popularity aware content retrieval scheme makes use of Information Retrieval (IR) techniques to find the most relevant data towards user's query, but significantly different from IR techniques by taking the data popularity factor into consideration. The popularity aware data replacement algorithm ensures that the density of different data is proportional to the square-root of their popularity in the system steady state, which firmly obeys the optimal "square-root" replication rule [6]. Results based on real city map and real traffic model show that Roadcast outperforms other content sharing schemes in VANETs.
Dust Processing and Grain Growth in Protoplanetary Disks in the Taurus-Auriga Star-Forming Region

Mid-infrared spectra of 65 T Tauri stars (TTS) taken with the Infrared Spectrograph (IRS) on board the Spitzer Space Telescope are modeled using populations of optically thin warm and cool grains to probe the radial variation in dust composition in the uppermost layers of protoplanetary disks. Most spectra with narrow emission features associated with crystalline silicates require Mg-rich minerals and silica, while a few spectra with these features suggest the presence of other components. IRS spectra indicating the presence of large amounts of warm enstatite of ~400-500 K require crystalline silicates (enstatite or forsterite) at temperatures lower than the median temperature of the cool dust in the models, ~127 K; spectra showing a high abundance of other crystalline silicates (forsterite or silica) typically do not. A few spectra show 10 ?m complexes of very small equivalent width. They are fit well using abundant crystalline silicates but very few large grains, inconsistent with the expectation that a low peak-to-continuum ratio of the 10 ?m complex always indicates grain growth. Most of the spectra in our sample are fit well without using the opacities of large crystalline silicate grains. If large grains grow by agglomeration of submicron grains of all dust types, the amorphous silicate components of these aggregates must typically be more abundant than the crystalline silicate components. We also find that the more there is of one crystalline dust species, the more there is of the others. This could suggest that crystalline silicates are processed directly from amorphous silicates, whether through evaporation of the amorphous grains and condensation in chemical equilibrium or by annealing of the amorphous precursors. Alternatively, if one kind of crystalline silicate transforms into another kind, it suggests that the intermediate species transforms into the end-product species at a slower rate than the precursor transforms into the intermediate species; otherwise, there would be a negligible abundance of intermediate species. It is also found that the crystalline silicate abundance is correlated tightly with disk geometry, in the sense of higher crystallinity accompanying more-settled disks, which are commonly associated with growth and settling of grains. The abundance of large grains is also correlated with disks that are more highly settled, but with a wide range of large grain abundance for a given degree of settling. We interpret this range as that the settling of large grains is sensitive to individual disk properties. We also find that lower-mass stars have higher abundances of large grains in their inner regions.