cssi/SciSciGPT-SciSciNet huggingface dataset:
Mechanisms of tumor cell extravasation in an in vitro microvascular network platform

A deeper understanding of the mechanisms of tumor cell extravasation is essential in creating therapies that target this crucial step in cancer metastasis. Here, we use a microfluidic platform to study tumor cell extravasation from in vitro microvascular networks formed via vasculogenesis. We demonstrate tight endothelial cell–cell junctions, basement membrane deposition and physiological values of vessel permeability. Employing our assay, we demonstrate impaired endothelial barrier function and increased extravasation efficiency with inflammatory cytokine stimulation, as well as positive correlations between the metastatic potentials of MDA-MB-231, HT-1080, MCF-10A and their extravasation capabilities. High-resolution time-lapse microscopy reveals the highly dynamic nature of extravasation events, beginning with thin tumor cell protrusions across the endothelium followed by extrusion of the remainder of the cell body through the formation of small (∼1 μm) openings in the endothelial barrier which grows in size (∼8 μm) to allow for nuclear transmigration. No disruption to endothelial cell–cell junctions is discernible at 60×, or by changes in local barrier function after completion of transmigration. Tumor transendothelial migration efficiency is significantly higher in trapped cells compared to non-trapped adhered cells, and in cell clusters versus single tumor cells.
Constraints on Intracluster Gas Bulk Motions in Clusters of Galaxies with ASCA

The recent detection of Doppler shifts of X-ray spectral lines in the intracluster gas of the Centaurus and Perseus clusters of galaxies with ASCA has raised the question of the frequency of such velocity gradients and their relation to other cluster properties. To address this and improve the sample of ICM velocity gradient candidates we carried out a systematic search of the ASCA archive for clusters with suitable observing conditions that allow full azimuthal mapping of gas velocities near the central regions. Here we present the results of the azimuthal velocity distribution of a sample consisting of the "best" observed clusters for velocity analysis. Our sample encompasses clusters with different physical and morphological characteristics, including both well-behaved "cooling flow" and dynamically active clusters. The gas temperatures of the clusters in our sample range from 1.4 to 6.3 keV. We find velocity substructures in ~15% of the clusters in our sample on the order of a few ×103 km s-1. The significance of the velocity gradients' is greater than 99% in Abell 576 and RX J0419.6+0225, the clusters where velocity gradients are most significant. The velocity gradients are consistent with transitory and/or rotational bulk motion. The velocity gradients in these clusters are unlikely to be due to projected temperature anisotropies, ASCA PSF, intrachip gain variations, and flux contamination from other sources. Chandra images of these clusters do not show obvious cluster alignments within the field of view covered by ASCA. We also noticed a high frequency (~50%) of anisotropic temperature gradients in the core of "cooling flow" clusters, suggesting the presence of frequent dynamical activity in the core of galaxy clusters.
Spectral Energy Distributions of Passive T Tauri Disks: Inclination

We compute spectral energy distributions (SEDs) for passive T Tauri disks viewed at arbitrary inclinations. Semianalytic models of disks in radiative and hydrostatic equilibrium are employed. Over viewing angles for which the flared disk does not occult the central star, the SED varies negligibly with inclination. For such aspects, the SED shortward of ~80 μm is particularly insensitive to orientation, since short wavelength disk emission is dominated by superheated surface layers, which are optically thin. The SED of a nearly edge-on disk is that of a class I source. The outer disk occults inner disk regions, and emission shortward of ~30 μm is dramatically extinguished. Spectral features from dust grains may appear in absorption. However, millimeter-wavelength fluxes decrease by at most a factor of 2 from face-on to edge-on orientations. We present illustrative applications of our SED models. The class I source 04108+2803B is considered a T Tauri star hidden from view by an inclined circumstellar disk. Fits to its observed SED yield model-dependent values for the disk mass of ~0.015 M_☉ and a disk inclination of ~65° relative to face-on. The class II source GM Aur represents a T Tauri star only slightly obscured by its circumstellar disk. Fitted parameters include a disk mass of ~0.050 M_☉ and an inclination of ~60°, where the viewing angle is chosen to reproduce the observed visual extinction of A_V = 0.5 mag.
Magnetically Driven Accretion Flows in the Kerr Metric I: Models and Overall Structure

This is the first in a series of papers that investigate the properties of accretion flows in the Kerr metric through three-dimensional general relativistic magnetohydrodynamic simulations of tori with a nearly Keplerian initial angular velocity profile. We study four models with increasing black hole spin, from a/M = 0 to 0.998, for which the structural parameters of the initial tori are maintained nearly constant. The subsequent accretion flows arise self-consistently from stresses and turbulence created by the magnetorotational instability. We investigate the overall evolution and the late-time global structure in the resulting nonradiative accretion flows, including the magnetic fields within the disks, the properties of the flow in the plunging region, and the flux of conserved quantities into the black hole. Independent of black hole spin, the global structure is described in terms of five regions: the main disk body, the coronal envelope, the inner disk (consisting of an inner torus and plunging region), an evacuated axial funnel, and a biconical outflow confined to the corona-funnel boundary. We find evidence for lower accretion rates, stronger funnel-wall outflows, and increased stress in the near-hole region with increasing black hole spin.
Millimeter-wave integrated circuits

Monolithic millimeter-wave integrated circuits have been designed and fabricated on semi-insulating GaAs substrates using microstrip transmission lines. Circuits using hybrid techniques have also been constructed on quartz and ceramics. This paper shows that microstrip-line integrated circuits are feasible at millimeter-wave frequencies. Circuit functions have been constructed and tested in the 25- to 100-GHz range. The loss in microstrip line on semi-insulating GaAs was found to be less than 0.3 dB/λ. Couplers from waveguide to microstrip have been made with transmission losses less than 0.5 dB. Monolithic integrated detectors showed 5-dB better sensitivity than a 1N53 diode in a philips detector mount. Monolithic diodes delivered 1.5 mW at 28 GHz. The results are encouraging and a fully monolithic integrated receiver is under development.
Global mineral distributions on Mars

[1] Determining the mineralogy of Mars is an essential part of revealing the conditions of the surface and subsurface. A deconvolution method was used to remove atmospheric components and determine surface mineralogy from Thermal Emission Spectrometer data at 1 pixel per degree (ppd). Minerals are grouped into categories on the basis of compositional and spectral similarity, and global concentration maps are produced. All binned pixels are fit well with RMS errors of ≤0.005 in emissivity. Higher RMS errors are attributed to short wavelength particle size effects on dust-covered surfaces. Significant concentrations (>0.10) of plagioclase, high-Ca pyroxene, sheet silicates/high-Si glass, and hematite are detected and display distributions consistent with previous studies. Elevated concentrations of plagioclase and high-Ca pyroxene are consistent with basaltic surfaces and are located in low-albedo highlands regions north of ∼45°S. Significant concentrations of plagioclase and sheet silicates/high-Si glass and low concentrations of high-Ca pyroxenes are consistent with andesitic surfaces and are concentrated in both southern and northern high-latitude, low-albedo regions. Andesitic surfaces in the southern hemisphere have a lower spectral contrast than northern surfaces. An isolated surface located in Solis Planum is spectrally distinct but compositionally similar to other surfaces interpreted to be andesitic in composition. Concentrations of olivine below the detection limit correctly identify its presence in two of three locations. Potassium feldspar, low-Ca pyroxene, basaltic glass, olivine, sulfate, carbonate, quartz, and amphibole are not detected with confidence at 1 ppd. The results presented here indicate a predominance of volcanic compositions within Martian dust-free surfaces.
Observation of phase coherent amplification of atomic matter waves

Summary form only given. Atomic matter waves, just like electromagnetic waves, can be focused, reflected, guided and split by the passive atom optical elements of today. However, the key for many applications of RF and light waves lies in the availability of amplifiers. Here, we report the observation of phase coherent amplification of atomic matter waves.
Squeezing the Arimoto–Blahut Algorithm for Faster Convergence

The Arimoto-Blahut algorithm for computing the capacity of a discrete memoryless channel is revisited. A so-called “squeezing” strategy is used to design algorithms that preserve its simplicity and monotonic convergence properties, but have provably better rates of convergence.
Energy Capacity Criterion for the Design of Columns against Collapse

Current practice in buckling design is based on the ultimate strength of a member such that excessive lateral deflections do not occur. This ultimate strength is often dictated by empirically derived formulae which correspond to postulated element imperfections including residual stresses. In this paper, the postbuckling behavior of columns is considered, and the limit state is considered to be total collapse. The load versus end displacement relationship is derived for a simplified elastic–perfectly plastic column model. Using this curve, the energy absorbed and released in going from one load/deflection state to another can be easily quantified. With this, the energy absorption capacity of an already loaded column is considered to be the critical performance metric. This “energy capacity criterion” is then used to develop alternative design curves for different levels of energy absorption capacity.
Analysis and measurement of thermal resistance in a 3-dimensional silicon multichip module populated with assembly test chips

A three-dimensional multichip module (MCM) using a silicon-on-silicon architecture has been constructed to evaluate the thermal performance of various design schemes. The module has three planes of die, each populated of four assembly test chips (ATCs). Each chip has an array of 48 temperature sensing diodes, which are used to map the temperature distribution across the chip surface. The design and construction of the module are discussed and the calibration of the diodes are reviewed. Experimental results are presented for the top surface temperature distribution with the bottom substrate connected to a heat sink. These results are compared to those from a full finite element calculation as well as to results using more approximate thermal analysis tools. >
Seasonal effects of water quality: The hidden costs of the Green Revolution to infant and child health in India☆

article i nfo Thispaperexaminesthe impact of fertilizeragrichemicals inwater on infantand child health using waterquality data combined with data on child health outcomes from the Demographic and Health Surveys of India. Because fertilizers are applied at specific times in the growing season, the concentrations of agrichemicals in water vary seasonally and by cropped area as some Indian states plant predominantly summer crops while others plant winter crops. Our identification strategy exploits the differing timing of the planting seasons across states and differing seasonal prenatal exposure to agrichemicals to identify the impact of agrichemical contamination on
Firm Strategies in the “Mid Tail” of Platform-Based Retailing

While millions of products are sold on its retail platform, Amazon.com itself stocks and sells only a very small fraction of them. Most of these products are sold by third-party sellers who pay Amazon a fee for each unit sold. Empirical evidence clearly suggests that Amazon tends to sell high-demand products and leave long-tail products for independent sellers to offer. We investigate how a platform owner such as Amazon, facing ex ante demand uncertainty, may strategically learn from these sellers' early sales which of the “mid-tail” products are worthwhile for its direct selling and which are best left for others to sell. The platform owner's “cherry-picking” of the successful products, however, gives an independent seller the incentive to mask any high demand by lowering his sales with a reduced service level unobserved by the platform owner. We analyze this strategic interaction between a platform owner and an independent seller using a game-theoretic model with two types of sellers---one with high demand and one with low demand. We show that it may not always be optimal for the platform owner to identify the seller's demand. Interestingly, the platform owner may be worse off by retaining its option to sell the independent seller's product, whereas both types of sellers may benefit from the platform owner's threat of entry. The platform owner's entry option may reduce consumer surplus in the early period, although it increases consumer surplus in the later period. We also investigate how consumer reviews influence the market outcome.
The use of the FFT for the efficient solution of the problem of electromagnetic scattering by a body of revolution

The enhancement of the computational efficiency of the body of revolution scattering problem is discussed with a view of making it practical for solving large body problems. The problem of the electromagnetic scattering by a perfectly conducting body is considered, although the methods provided can be extended to multilayered dielectric bodies as well. Typically, the generation of the elements of the moment method matrix consumes a major portion of the computational time. It is shown how this time can be significantly reduced by manipulating the expression for the matrix elements in a manner that allows one to compute them efficiently by using the fast Fourier transform (FFT). A technique for extracting the singularity of the Green's function that appears within the integrands of the matrix diagonal is also presented, further enhancing the usefulness of the FFT. It is shown that, with the use of the method discussed here, the computational time can be improved by at least an order of magnitude for large bodies in comparison to that for previous algorithms. >
The leadership gap

Executive Overview Zaleznik's article is a critical assessment of a mystique that places a premium on the team over the individual as practiced in business and taught in our business schools. It's an argument for substance over process that calls for restoring the individual to his or her proper place as the source of vision and drive that can make an organization unique. The image of leadership projected is one of substance, humanity, and morality, which are qualities Zaleznik believes are painfully short in our collective lives. Good ideas and exciting directions generate enthusiasm, support, and cohesion in an organization. Professional managers with their bag of tools can indeed coordinate and control, but have lost sight of the substance of work in business. Self-esteem follows, not from submerging oneself in the team and following process, but from facing problems, assuming responsibility, and doing good work. Zaleznik argues the business schools have served as socialization plants to fit managers f...
Organic-inorganic nanocomposites composed of conjugated polymers and semiconductor nanocrystals for photovoltaics

Semiconductor organic-inorganic nanocomposites have garnered much attention as they integrate the advantageous properties from conjugated polymers (CPs) and semiconductor nanocrystals (NCs). Recent developments in interfacial engineering of CP-NC nanocomposites enabled the intimate contact between CPs and NCs, thereby facilitating charge separation between these two constituents. To capitalize on the use of CP-NC nanocomposites for hybrid solar cells, several issues need to be addressed, including materials design and engineering, light harvesting, and morphology of photoactive layer. In this Review, the general working principle of hybrid solar cells and the development of p-type and n-type CPs are briefly introduced, followed by the highlight of recent advances in synthesis of CP-NC nanocomposites in which CP and NC are in intimate contact for hybrid solar cells, and the discussion on various strategies for potentially improved power conversion efficiency. An outlook for future directions in this area is also presented. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 1641–1660
Outage and error events in bursty channels

In this paper the outage concept is discussed. Classic definitions, only based on the marginal statistics, are found not to be adequate for a proper characterization of the effect of channel impairments at the application level. A more flexible definition, which incorporates time parameters and appears suitable for the characterization of the performance of packet communications systems, is proposed. An analytical framework for the computation of various performance metrics is also presented. A Markov description is assumed for the channel, which allows closed-form solutions and can effectively model many situations of interest. Outage events are defined as being triggered by T/sub b/ consecutive channel errors, and being ended by T/sub g/ consecutive successes. A numerical example of application is given and extensions of the analysis to more general definitions are discussed.
Cramer-Rao Bounds for Joint RSS/DoA-Based Primary-User Localization in Cognitive Radio Networks

Knowledge about the location of licensed primary-users (PU) could enable several key features in cognitive radio (CR) networks including improved spatio-temporal sensing, intelligent location-aware routing, as well as aiding spectrum policy enforcement. In this paper we consider the achievable accuracy of PU localization algorithms that jointly utilize received-signal-strength (RSS) and direction-of-arrival (DoA) measurements by evaluating the Cramer-Rao Bound (CRB). Previous works evaluate the CRB for RSS-only and DoA-only localization algorithms separately and assume DoA estimation error variance is a fixed constant or rather independent of RSS. We derive the CRB for joint RSS/DoA-based PU localization algorithms based on the mathematical model of DoA estimation error variance as a function of RSS, for a given CR placement. The bound is compared with practical localization algorithms and the impact of several key parameters, such as number of nodes, number of antennas and samples, channel shadowing variance and correlation distance, on the achievable accuracy are thoroughly analyzed and discussed. We also derive the closed-form asymptotic CRB for uniform random CR placement, and perform theoretical and numerical studies on the required number of CRs such that the asymptotic CRB tightly approximates the numerical integration of the CRB for a given placement.
Pericyclic umpolung. Reversal of regioselectivity in the diels-alder reaction

Abstract New methodology is reported which enables reversal of regiochemistry in the Diels-Alder reaction. Esterification of 2-(β-hydroxyethyl)dimerhylsilydienes with common dienophiles followed by type 2 intramolecular Diels-Alder reaction results in formation of a single regio- and stereoisomer. Oxidative cleavage of the cycloadduct produces a cyclohexanone with a substitution pattern opposite of that found in the analogous bimolecular cycloaddition reaction.
Efficiency of Scalar-Parameterized Mechanisms

We consider the problem of allocating a fixed amount of an infinitely divisible resource among multiple competing, fully rational users. We study the efficiency guarantees that are possible when we restrict to mechanisms that satisfy certain scalability constraints motivated by large-scale communication networks; in particular, we restrict attention to mechanisms where users are restricted to one-dimensional strategy spaces. We first study the efficiency guarantees possible when the mechanism is not allowed to price differentiate. We study the worst-case efficiency loss (ratio of the utility associated with a Nash equilibrium to the maximum possible utility), and show that Kelly's proportional allocation mechanism minimizes the efficiency loss when users are price anticipating. We then turn our attention to mechanisms where price differentiation is permitted; using an adaptation of the Vickrey-Clarke-Groves class of mechanisms, we construct a class of mechanisms with one-dimensional strategy spaces where Nash equilibria are fully efficient. These mechanisms are shown to be fully efficient even in general convex environments, under reasonable assumptions. Our results highlight a fundamental insight in mechanism design: when the pricing flexibility available to the mechanism designer is limited, restricting the strategic flexibility of bidders may actually improve the efficiency guarantee.
Examining Cross-Country Agricultural Productivity Differences

This paper computes Malmquist agricultural productivity indexes for 125 countries over the period 1961-2001. These are decomposed into efficiency change (i.e., pure technical efficiency and scale efficiency changes) and technical change (i.e., input bias and magnitude components). Results show that developing and developed countries derive their growth from efficiency change and technical change, respectively. Input bias technical change is evident for both developing and developed countries.
Main Drivers of Income Inequality in Central European and Baltic Countries: Some Insights from Recent Household Survey Data

Present levels of income inequality in Czech Republic, Estonia, Latvia, Lithuania, Hungary, Poland, Slovakia, and Slovenia remain considerably higher than their pre-transition levels, although the relative pace of change over time has varied quite a bit across countries. Using data from the 2006 European Union Survey of Income and Living Conditions, this paper finds that prevailing levels of income inequality in these countries continue to be low by international standards, and that this is in large part due to the very high redistributive impact of direct taxes and public transfers. In addition to the instrumental role of tax and transfer policies in redistributing income, the paper highlights the important role played by differences in education levels and labor market participation rates in explaining observed inequalities across people and across different regions (although not in explaining observed differences across countries). The paper includes an analysis of key factors that help explain observed variation across countries in the level of public support for redistribution, including peoples' economic background and relative success in life, whether they perceive poverty to be associated with factors within or outside the control of those it afflicts (for example, laziness/lack of willpower vs. injustice in society).
Slow Mixing of Markov Chains Using Fault Lines and Fat Contours

We show that local dynamics require exponential time for two sampling problems motivated by statistical physics: independent sets on the triangular lattice (the hard-core lattice gas model) and weighted even orientations of the two-dimensional Cartesian lattice (the 8-vertex model). For each problem, there is a parameter λ known as the fugacity, such that local Markov chains are expected to be fast when λ is small and slow when λ is large. Unfortunately, establishing slow mixing for these models has been a challenge, as standard contour arguments typically used to show that a chain has small conductance do not seem to apply. We modify this approach by introducing the notion of fat contours that can have nontrivial area, and use these to establish slow mixing of local chains defined for these models.
Back to Work: Expectations and Realizations of Work after Retirement

This paper analyzes a puzzling aspect of retirement behavior known as "unretirement." Nearly 50 percent of retirees follow a nontraditional retirement path that involves partial retirement or unretirement, and at least 26 percent of retirees later unretire. I explore two possible explanations: 1) unretirement transitions result from failures in planning or financial shocks; and 2) unretirement transitions are anticipated prior to retirement, reflecting a more complex retirement process. I show that unretirement was anticipated for the vast majority of those returning to work, and is not a result of financial shocks, poor planning or low wealth accumulation.
Restricted strong convexity and weighted matrix completion: optimal bounds with noise

We consider the matrix completion problem under a form of row/column weighted entrywise sampling, including the case of uniformentrywise sampling as a special case. We analyze the associated random observation operator, and prove that with high probability, it satisfies a form of restricted strong convexity with respect to weighted Frobenius norm. Using this property, we obtain as corollaries a number of error bounds on matrix completion in the weighted Frobenius norm under noisy sampling and for both exact and near low-rank matrices. Our results are based on measures of the 'spikiness' and 'low-rankness' of matrices that are less restrictive than the incoherence conditions imposed in previous work. Our technique involves an M-estimator that includes controls on both the rank and spikiness of the solution, and we establish non-asymptotic error bounds in weighted Frobenius norm for recovering matrices lying with lq-"balls" of bounded spikiness. Using information-theoretic methods, we show that no algorithm can achieve better estimates (up to a logarithmic factor) over these same sets, showing that our conditions on matrices and associated rates are essentially optimal.
THE EFFECTS OF FINANCIAL EDUCATION IN THE WORKPLACE: EVIDENCE FROM A SURVEY OF EMPLOYERS

We examine the effects of education on financial decision-making skills by identifying an interesting source of variation in pertinent training. During the 1990s, an increasing number of individuals were exposed to programs of financial education provided by their employers. If, as some have argued, low saving frequently results from a failure to appreciate economic vulnerabilities, then education of this form could prove to have a powerful effect on behavior. The current paper undertakes an analysis of these programs using a previously unexploited survey of employers. We find that both participation in and contributions to voluntary savings plans are significantly higher when employers offer retirement seminars. The effect is typically much stronger for non-highly compensated employees than for highly compensated employees. The frequency of seminars emerges as a particularly important correlate of behavior. We are unable to detect any effects of written materials, such as newsletters and summary plan descriptions, regardless of frequency. We also present evidence on other determinants of plan activity.
Rigidity of Spherical Codes

A packing of spherical caps on the surface of a sphere (that is, a spherical code) is called rigid or jammed if it is isolated within the space of packings. In other words, aside from applying a global isometry, the packing cannot be deformed. In this paper, we systematically study the rigidity of spherical codes, particularly kissing configurations. One surprise is that the kissing configuration of the Coxeter–Todd lattice is not jammed, despite being locally jammed (each individual cap is held in place if its neighbors are fixed); in this respect, the Coxeter–Todd lattice is analogous to the face-centered cubic lattice in three dimensions. By contrast, we find that many other packings have jammed kissing configurations, including the Barnes–Wall lattice and all of the best kissing configurations known in four through twelve dimensions. Jamming seems to become much less common for large kissing configurations in higher dimensions, and in particular it fails for the best kissing configurations known in 25 through 31 dimensions. Motivated by this phenomenon, we find new kissing configurations in these dimensions, which improve on the records set in 1982 by the laminated lattices.
Speech Patterns and Racial Wage Inequality

Speech patterns differ substantially between whites and many African Americans. I collect and analyze speech data to understand the role that speech may play in explaining racial wage differences. Among blacks, speech patterns are highly correlated with measures of skill such as schooling and AFQT scores. They are also highly correlated with the wages of young workers. Even after controlling for measures of skill and family background, black speakers whose voices were distinctly identified as black by anonymous listeners earn about 12 percent less than whites with similar observable skills. Indistinctly identified blacks earn essentially the same as comparable whites. I discuss a number of models that may be consistent with these results and describe the data that one would need to distinguish among them.
Strong forms of linearization for Hopf monoids in species

A vector species is a functor from the category of finite sets with bijections to vector spaces; informally, one can view this as a sequence of $$S_n$$Sn-modules. A Hopf monoid (in the category of vector species) consists of a vector species with unit, counit, product, and coproduct morphisms satisfying several compatibility conditions, analogous to a graded Hopf algebra. We say that a Hopf monoid is strongly linearized if it has a "basis" preserved by its product and coproduct in a certain sense. We prove several equivalent characterizations of this property and show that any strongly linearized Hopf monoid, which is commutative and cocommutative, possesses four bases, which one can view as analogs of the classical bases of the algebra of symmetric functions. There are natural functors which turn Hopf monoids into graded Hopf algebras, and applying these functors to strongly linearized Hopf monoids produces several notable families of Hopf algebras. For example, in this way, we give a simple unified construction of the Hopf algebras of superclass functions attached to the maximal unipotent subgroups of three families of classical Chevalley groups.
Structure of a novel antimalarial gallium(III) complex with selective activity against chloroquine-resistant Plasmodium falciparum

The crystal structure of an amine phenol complex of gallium(III), [{1,12-bis(2-hydroxy-3-methoxybenzyl)-1,5,8,12-tetraazadodecane}gallium(III)] [Ga(madd)]+, a potent new antimalarial which selectively targets chloroquine-resistant organisms is reported; the compound is shown to directly inhibit heme polymerization.
The long march of history: Farm wages, population, and economic growth, England 1209–1869†

SUMMARY The article forms three series for English farm workers from 1209–1869: nominal day wages, the implied marginal product of a day of farm labour, and the purchasing power of a day’s wage in terms of farm workers’ consumption. These series suggest that labour productivity in English agriculture was already high in the middle ages. Furthermore, they fit well with one method of estimating medieval population that suggests a peak English population c.1300 of nearly 6 million. Lastly, they imply that both agricultural technology and the general efficiency of the economy were static from 1250 till 1600. Economic changes were in these years entirely a product of demographic shifts. From 1600 to 1800, technological advance in agriculture provided an alternative source of dynamism in the English economy.
Effective medium theory for drag-reducing micro-patterned surfaces in turbulent flows

Many studies in the last decade have revealed that patterns at the microscale can reduce skin drag. Yet, the mechanisms and parameters that control drag reduction, e.g. Reynolds number and pattern geometry, are still unclear. We propose an effective medium representation of the micro-features, that treats the latter as a porous medium, and provides a framework to model turbulent flow over patterned surfaces. Our key result is a closed-form expression for the skin friction coefficient in terms of frictional Reynolds (or Karman) number in turbulent regime, the viscosity ratio between the fluid in and above the features, and their geometrical properties. We apply the proposed model to turbulent flows over superhydrophobic ridged surfaces. The model predictions agree with laboratory experiments for Reynolds numbers ranging from 3000 to 10000.
Mass Limits For Black Hole Formation

We present a series of two-dimensional core-collapse supernova simulations for a range of progenitor masses and different input physics. These models predict a range of supernova energies and compact remnant masses. In particular, we study two mechanisms for black hole formation: prompt collapse and delayed collapse owing to fallback. For massive progenitors (greater than 20 M☉), after a hydrodynamic time for the helium core (a few minutes to a few hours), fallback drives the compact object beyond the maximum neutron star mass, causing it to collapse into a black hole. With the current accuracy of the models, progenitors more massive than 40 M☉ form black holes directly with no supernova explosion (if rotating, these black holes may be the progenitors of gamma-ray bursts). We calculate the mass distribution of black holes formed and compare these predictions to the observations, which represent a small biased subset of the black hole population. Uncertainties in these estimates are discussed.
Do read errors matter for genome assembly

While most current high-throughput DNA sequencing technologies generate short reads with low error rates, emerging sequencing technologies generate long reads with high error rates. A basic question of interest is the tradeoff between read length and error rate in terms of the information needed for the perfect assembly of the genome. Using an adversarial erasure error model, we make progress on this problem by establishing a critical read length, as a function of the genome and the error rate, above which perfect assembly is guaranteed. For several real genomes, including those from the GAGE dataset, we verify that this critical read length is not significantly greater than the read length required for perfect assembly from reads without errors.
H → WW as the discovery mode for a light Higgs boson

Abstract The production cross section for a m H ≈115 GeV, SM Higgs boson in weak boson fusion at the LHC is sizable. However, the branching fraction for H → W + W − is expected to be relatively small. The signal, with its two forward jets, is sufficiently different from the main backgrounds that a signal to background ratio of better than 1:1 can nevertheless be obtained, with large enough rate to allow for a 5 σ signal with 35 fb −1 of data. The H → WW signal in weak boson fusion may thus prove to be the discovery mode for the Higgs boson at the LHC.
Quantitative determination of a selective alpha-1a receptor antagonist in human plasma by high-performance liquid chromatography with tandem mass spectrometric detection

Solid-phase extraction, utilizing a 96-well plate format, was used to isolate an alpha-1a receptor antagonist and internal standard from human plasma. Following the isolation procedure, the analyte and internal standard were separated and detected using reversed-phase HPLC coupled with atmospheric pressure chemical ionization (APCI) mass spectrometry operated in the positive ion multiple reaction monitoring (MRM) mode. Based upon the peak area ratio (analyte: internal standard) the analyte was quantified over a concentration range of 0.02-2 ng/ml. Assay validation results including parameters such as precision and accuracy are presented. The validated method was subsequently used to support human pharmacokinetic studies.
Information Sharing and Oligopoly in Agricultural Markets: The Role of Bargaining Associations

We study incentives for information sharing (about uncertain future demand for final output) among firms in imperfectly competitive markets for farm output. Information sharing generally leads to increases in expected total welfare but may reduce expected firm profits. Even when expected firm profits increase, information sharing does not represent equilibrium behavior because firms face a prisoner?s dilemma in which it is privately rational for each firm to withhold information, given that other firms report truthfully. This equilibrium can be overcome if firms commit to simultaneously reporting their information and if reports are verifiable. We argue that agricultural bargaining associations serve both these roles.
A Fracture-Mechanics-Based Methodology for Fatigue Life Prediction of Single Crystal Nickel-Based Superalloys

A comprehensive fracture-mechanics-based life prediction methodology is presented for fcc single crystal components based on the computation of stress intensity factors (SIFs), and the modeling of the crystallographic fatigue crack growth (FCG) process under mixed-mode loading conditions. The 3D finite element numerical procedure presented for computing SIFs for anisotropic materials under mixed-mode loading is very general and not just specific to fcc single crystals. SIFs for a Brazilian disk specimen are presented for the crack on the {111}) plane in the 101 and 121 directions, which represent the primary and secondary slip directions. Variation of SIFs as a function of thickness is also presented. Modeling of the crystallographic FCG behavior is performed by using the resolved shear stress intensity coefficient, Krss. This parameter is sensitive to the grain orientation and is based on the resolved shear stresses on the slip planes at the crack tip, which is useful in identifying the active crack plane as well as in predicting the crack growth direction. A multiaxial fatigue crack driving force parameter, Krss, was quantified, which can be used to predict the FCG rate and, hence, life in single crystal components subject to mixed-mode fatigue loading. DOI: 10.1115/1.2838990
Stand Your Ground Laws, Homicides, and Injuries

This paper examines the impact of Stand Your Ground laws on firearm homicides and injuries. Using state-level monthly data and a difference-in-difference identification strategy, we find that these laws result in an increase in homicides. According to our estimates, at least 30 individuals are killed each month as a result of Stand Your Ground laws. Furthermore, we document evidence to suggest that these laws also are associated with an increase in hospitalizations related to firearm-inflicted injuries. Taken together, the findings in this paper raise serious doubts against the argument that Stand Your Ground laws make the public safer.
Conductive Polymer and Silicon Composite Secondary Particles for a High Area-Loading Negative Electrode

Author(s): Xun, S; Xiang, B; Minor, A; Battaglia, V; Liu, G | Abstract: A conductive polymer and silicon nanoparticles were used to form elastic and porous micron-sized composite secondary particles using spray precipitation method. These composite secondary particles are used to fabricate a lithium-ion anode electrode. Although the Si volume changes during charge and discharge process, the composite secondary particles retain their size during these processes, to maintain a stable electrode microstructure. This dimension stability leads to improved electrode cycling stability and enhanced rate performance. © 2013 The Electrochemical Society. All rights reserved.
Principal series representations of direct limit groups

We combine the geometric realization of principal series representations on partially holomorphic cohomology spaces, with the Bott–Borel–Weil theorem for direct limits of compact Lie groups, obtaining limits of principal series representations for direct limits of real reductive Lie groups. We introduce the notion of weakly parabolic direct limits and relate it to the conditions that the limit representations are norm-preserving representations on a Banach space or unitary representations on a Hilbert space. We specialize the results to diagonal embedding direct limit groups. Finally we discuss the possibilities of extending the results to limits of tempered series other than the principal series.
Multifocal three-dimensional bootlace lenses

It is well known that a two-dimensional (parallel plate configuration) bootlace lens can be designed to have more than one focal point. Wide angle scanning capabilities of these lenses in two dimensions is well established, being larger for higher number of focal points. However, no three-dimensional bootlace lens having more than one focal point has been reported. It is the purpose of this paper to report on three-dimensional bootlace lenses having two, three, and four perfect focal points. Equations for lens surfaces are obtained for all three cases. The results of the aperture phase error analysis show that a lens with a larger number of focal points can be scanned to much larger angles in one plane at the expense of the scanning capability in the orthogonal plane.
Managing Asthma Exacerbations in the Emergency Department: Summary of the National Asthma Education and Prevention Program Expert Panel Report 3 Guidelines for the Management of Asthma Exacerbations

This article summarizes the recommendations regarding the management of asthma exacerbations presented in the Expert Panel Report 3 (EPR3). The evidence supporting these recommendations can be found in the report itself. All of the recommendations in this article are strong recommendations, unless indicated by the term conditional. Asthma exacerbations consist of acute or subacute episodes of progressively worsening shortness of breath, coughing, wheezing, and chest tightness or any combination thereof. These episodes differ from poor asthma control in that diurnal variability in airflow, a key marker of poor asthma control, might not change during an exacerbation. An important advance in the new National Asthma Education and Prevention Program (NAEPP) EPR3 guidelines is the creation of a chapter devoted to the management of asthma exacerbations. Moreover, the new EPR3 guidelines present different spirometry cut points for assessing the severity of acute asthma (exacerbations) versus chronic asthma. These and other changes underscore the distinction between acute and chronic asthma management. Two patient populations at particular risk during an asthma exacerbation include patients with 1 or more risk factors for asthma-related death (Table I) and infants, who are at greater risk
Intramolecular reactions of unactivated alkenes with conjugated dienones

Abstract Lewis acid- or Amberlyst resin-promoted cyclizations of unactivated alkenes with 3-vinylcycloalkenones afford a variety of polycyclic systems.
Resolving the Formation of Protogalaxies. II. Central Gravitational Collapse

Numerous cosmological hydrodynamic studies have addressed the formation of galaxies. Here we choose to study the first stages of galaxy formation, including nonequilibrium atomic primordial gas cooling, gravity, and hydrodynamics. Using initial conditions appropriate for the concordance cosmological model of structure formation, we perform two adaptive mesh refinement simulations of ~108 M☉ galaxies at high redshift. The calculations resolve the Jeans length at all times with more than 16 cells and capture over 14 orders of magnitude in length scales. In both cases, the dense, 105 solar mass, one parsec central regions are found to contract rapidly and have turbulent Mach numbers up to 4. Despite the ever decreasing Jeans length of the isothermal gas, we only find one site of fragmentation during the collapse. However, rotational secular bar instabilities transport angular momentum outward in the central parsec as the gas continues to collapse and lead to multiple nested unstable fragments with decreasing masses down to sub-Jupiter mass scales. Although these numerical experiments neglect star formation and feedback, they clearly highlight the physics of turbulence in gravitationally collapsing gas. The angular momentum segregation seen in our calculations plays an important role in theories that form supermassive black holes from gaseous collapse.
International trade and inclusive growth : a primer for busy policy analysts

This note provides two analytical frameworks for understanding the role of trade in promoting inclusive growth in developing economies. A working definition of inclusive growth focuses on long-term, sustained growth associated with productivity growth and employment opportunities for broad portions of households and firms within countries. International integration can promote inclusive growth when workers and firms are able to adjust to enter into growing economic activities and adopt technologies availed through international trade. The frameworks described in this note build on simple household and firm choice models, which require only basic knowledge of development economics. The discussion highlights how these frameworks can help analysts focus on research and policy questions related to the impacts of international trade across the distribution of households and firms within countries. It also discusses publicly available data sets that can be used to explore some aspects of inclusive growth. In addition, the note highlights important caveats that need to be acknowledged by analysts and discusses avenues for future research, which needs to be part and parcel of the inclusive growth agenda.
Tourism area life cycle extensions.

Abstract This paper investigates the effect of both strategic and environmental factors on the tourist area life cycle for Cypress Gardens. It is hypothesized that both types of factors can have a revitalization effect on the tourist area life cycle. A step-logarithmic function is used to model the attendance for the tourist attraction. Strategic and environmental factors are both found to have a significant effect on the life cycle and the step-logarithmic function demonstrates a very good model fit for the life cycle. The implications for tourist areas are discussed.
Smooth Optimization with Approximate Gradient

We show that the optimal complexity of Nesterov's smooth first-order optimization algorithm is preserved when the gradient is computed only up to a small, uniformly bounded error. In applications of this method to semidefinite programs, this means in some instances computing only a few leading eigenvalues of the current iterate instead of a full matrix exponential, which significantly reduces the method's computational cost. This also allows sparse problems to be solved efficiently using sparse maximum eigenvalue packages.