cssi/SciSciGPT-SciSciNet huggingface dataset:
Electromagnetically induced transparency and reduced speeds for single photons in a fully quantized model

We introduce a simple model for electromagnetically induced transparency in which all fields are treated quantum mechanically. We study a system of three separated atoms at fixed positions in a one-dimensional multimode optical cavity. The first atom serves as the source for a single spontaneously emitted photon; the photon scatters from a three-level 'Λ'-configuration atom which interacts with an additional single-mode field coupling two of the atomic levels; the third atom serves as a detector of the total transmitted field. We find an analytical solution for the quantum dynamics. From the quantum amplitude describing the excitation of the detector atom we extract information that provides exact single-photon analogues to wave delays predicted by semi-classical theories. We also find complementary information in the expectation value of the electric field intensity operator.
Reversible simulations of elastic collisions

Consider a system of N identical hard spherical particles moving in a d-dimensional box and undergoing elastic, possibly multiparticle, collisions. We develop a new algorithm that recovers the precollision state from the post-collision state of the system, across a series of consecutive collisions, with essentially no memory overhead. The challenge in achieving reversibility for an n-particle collision (where, in general, n L N) arises from the presence of nd - d - 1 degrees of freedom (arbitrary angles) during each collision, as well as from the complex geometrical constraints placed on the colliding particles. To reverse the collisions in a traditional simulation setting, all of the particular realizations of these degrees of freedom (angles) during the forward simulation must be tracked. This requires memory proportional to the number of collisions, which grows very fast with N and d, thereby severely limiting the de facto applicability of the scheme. This limitation is addressed here by first performing a pseudorandomization of angles, which ensures determinism in the reverse path for any values of n and d. To address the more difficult problem of geometrical and dynamic constraints, a new approach is developed which correctly samples the constrained phase space. Upon combining the pseudorandomization with correct phase space sampling, perfect reversibility of collisions is achieved, as illustrated for n ≤ 3, d = 2, and n = 2, d = 3. This result enables, for the first time, reversible simulations of elastic collisions with essentially zero memory accumulation. In principle, the approach presented here could be generalized to larger values of n. The reverse computation methodology presented here uncovers important issues of irreversibility in conventional models, and the difficulties encountered in arriving at a reversible model for one of the most basic and widely used physical system processes, namely, elastic collisions for hard spheres. Insights and solution methodologies, with regard to accurate phase space coverage with reversible random sampling proposed in this context, can help serve as models and/or starting points for other reversible simulations.
Measuring the Effect of Internet Adoption on Paper Consumption

A large fraction of the total supply of paper is produced with technologies that have serious adverse consequences on the environment and cause significant health problems, such as cancer. This paper reports on how Internet adoption affects paper consumption. The study used country-level panel data on Internet penetration and paper consumption disaggregated into various paper categories. The empirical strategy is to use fixed-effect models to study whether countries with faster Internet penetration growth have experienced faster declines in paper consumption. The analysis finds that Internet penetration significantly decreases aggregate paper consumption. Further, the estimates show that Internet growth reduces consumption for the paper categories that are more likely to be affected by the diffusion of the Internet (paper used to print newspapers and books and magazines), whereas the growth of the Internet does not have a statistically significant impact on a paper category unlikely to be affected by the Internet (such as sanitary paper).
Detection and classification of vehicles

This paper presents algorithms for vision-based detection and classification of vehicles in monocular image sequences of traffic scenes recorded by a stationary camera. Processing is done at three levels: raw images, region level, and vehicle level. Vehicles are modeled as rectangular patches with certain dynamic behavior. The proposed method is based on the establishment of correspondences between regions and vehicles, as the vehicles move through the image sequence. Experimental results from highway scenes are provided which demonstrate the effectiveness of the method. We also briefly describe an interactive camera calibration tool that we have developed for recovering the camera parameters using features in the image selected by the user.
Electrohydrodynamic gas pump in a vertical tube

The characteristics of electrohydrodynamic (EHD) gas pumps have been experimentally evaluated. Two tubes of different size were used to house the EHD gas pumps. Experiments were conducted using positive direct current with voltage varying from 13 kV to 30 kV. The applied voltage at which flow was induced correlates well with the electrode spacing. Air flows with a uniform velocity profile were induced in the smaller tube and an inverted parabolic profile in the larger tube. The results also show that the ionic wind velocity increases to a maximum value and then decreases to an asymptotic value.
"Engineeresses" invade campus: four decades of debate over technical coeducation

Engineering education in the United States has a gendered history, one that reveals an ongoing debate over women's place in the predominantly male engineering profession. Historically, women in engineering programs, even more than in science, have stood out due to their rarity. Their very presence thus led university communities to confront questions about what it means to be a man or a woman in a modern technological society, what it means to be an engineer. The article concentrates on four technically-centered schools that had, due to implicit or explicit policies, remained completely or virtually all-male up to WWII or beyond. These case studies demonstrate that in the debate about whether to become coeducational, faculty, administrators, students, and alumni came to confront a difficult set of issues concerning gender and technology, traditions which tied technical knowledge to masculinity. The very process of rethinking admission and education policies led these colleges to discuss whether or not women had a place studying engineering and if so, on what terms they should be admitted. The author's work examines the period from the 1940s through the 1970s, asking questions about when, why, and how four schools (Rensselaer Polytechnic Institute, the Georgia Institute of Technology, the California Institute of Technology, and the Massachusetts Institute of Technology), moved toward coeducation.
Technology-enabled employee wellness: Emerging trends, applications, and results

This presentation will provide a view into the emerging trends of technology-enabled solutions for employee wellness programs. We will examine what types of safety, cost, and productivity benefits an employer can expect to realize by implementing a state of the art wellness program. We will show examples of specific technologies, devices, programs, and services and best known practices that are available now and on the near term horizon that can be used to create a competitive advantage by optimizing the health, safety, and productivity of employees.
Spectral functions in mathematics and physics

Spectral functions relevant in the context of quantum field theory under the influence of spherically symmetric external conditions are analysed. Examples comprise heat-kernels, determinants and spectral sums needed for the analysis of Casimir energies. First, we summarize that a convenient way of handling them is to use the associated zeta function. A way to determine all its needed properties is derived. Using the connection with the mentioned spectral functions, we provide: i.) a method for the calculation of heat-kernel coefficients of Laplace-like operators on Riemannian manifolds with smooth boundaries and ii.) an analysis of vacuum energies in the presence of spherically symmetric boundaries and external background potentials.
Cosmology in a String-Dominated Universe

The string-dominated universe is a flat universe that locally resembles an open universe and fits dynamical measures of power spectra, cluster abundances, redshift distortions, lensing constraints, luminosity, angular diameter distance relations, and microwave background observations. We show examples of networks that might give rise to recent string-domination when formed by a phase transition near the electro-weak symmetry breaking scale. We discuss how future observations can distinguish this model from other cosmologies.
Black Holes with Hair

Among the most remarkable results of classical general relativity are the black hole uniqueness theorems for pure gravity and for gravity coupled to electromagnetism. The simplicity and elegance of these black holes inspired Chandrasekhar’s statement, in the prologue to his treatise [1], that “the black holes of nature are the most perfect macroscopic objects there are in the universe … and … they are the simplest objects as well”.
A 40-GHz frequency divider in 0.18-/spl mu/m CMOS technology

An analysis of regenerative dividers predicts the required phase shift or selectivity for proper operation. A divider topology is introduced that employs resonance techniques by means of on-chip spiral inductors to tune out the device capacitances. Configured as two cascaded /spl divide/2 stages, the circuit achieves a frequency range of 2.3 GHz at 40 GHz while consuming 31 mW from a 2.5-V supply.
Large-eddy simulations of Richtmyer–Meshkov instability in a converging geometry

This work presents on-going research on large-eddy simulations of shock-generated mixing in Richtmyer-Meshkov flow in converging geometries. A hybrid numerical method is used on each subgrid of the mesh hierarchy within the AMROC (adaptive mesh refinement object oriented C++) framework: it is a shock capturing method but reverts to a centered scheme with low numerical viscosity in regions of smoother flow. The stretched-vortex subgrid-scale model allows for the capturing of the small-scale mixing process between the two fluids. Results presented focus on the evolution of the mixing layer and its internal statistics including various spectra and p.d.f.s of mixed molar and mass fractions. A detailed quantitative analysis has also been conducted including space-time histories of instantaneous cylindrical shell-averages of diverse quantities, taken concentrically to the main shocks. Comparisons are made with the planar Richtmyer-Meshkov instability with reshock studied by Vetter and Sturtevant (1995) [1] and Hill et al. (2006).
Dynamic trees in practice

Dynamic tree data structures maintain forests that change over time through edge insertions and deletions. Besides maintaining connectivity information in logarithmic time, they can support aggregation of information over paths, trees, or both. We perform an experimental comparison of several versions of dynamic trees: ST-trees, ET-trees, RC-trees, and two variants of top trees (self-adjusting and worst-case). We quantify their strengths and weaknesses through tests with various workloads, most stemming from practical applications. We observe that a simple, linear-time implementation is remarkably fast for graphs of small diameter, and that worst-case and randomized data structures are best when queries are very frequent. The best overall performance, however, is achieved by self-adjusting ST-trees.
Models of Neptune-mass exoplanets: Emergent fluxes and albedos

There are now many known exoplanets with Msin i within a factor of 2 of Neptune's, including the transiting planets GJ 436b and HAT-P-11b. Planets in this mass range are different from their more massive cousins in several ways that are relevant to their radiative properties and thermal structures. By analogy with Neptune and Uranus, they are likely to have metal abundances that are an order of magnitude or more greater than those of larger, more massive planets. This increases their opacity, decreases Rayleigh scattering, and changes their equation of state. Furthermore, their smaller radii mean that fluxes from these planets are roughly an order of magnitude lower than those of otherwise identical gas giant planets. Here, we compute a range of plausible radiative equilibrium models of GJ 436b and HAT-P-11b. In addition, we explore the dependence of generic Neptune-mass planets on a range of physical properties, including their distance from their host stars, their metallicity, the spectral type of their stars, the redistribution of heat in their atmospheres, and the possible presence of additional optical opacity in their upper atmospheres.
Blind identification of multichannel FIR blurs and perfect image restoration

Despite its practical importance in image processing and computer vision, blind blur identification and blind image restoration have so far been addressed under restrictive assumptions such as all-pole stationary image models blurred by zero or minimum-phase point-spread functions. Relying upon diversity (availability of a sufficient number of multiple blurred images), we develop blind FIR blur identification and order determination schemes. Apart from a minimal persistence of the excitation condition (also present with nonblind setups), the inaccessible input image is allowed to be deterministic or random and of unknown color of distribution. With the blurs satisfying a certain co-primeness condition in addition, we establish existence and uniqueness results which guarantee that single input/multiple-output FIR blurred images can be restored blindly, though perfectly in the absence of noise, using linear FIR filters. Results of simulations employing the blind order determination, blind blur identification, and blind image restoration algorithms are presented. When the SNR is high, direct image restoration is found to yield better results than indirect image restoration which employs the estimated blurs. In low SNR, indirect image restoration performs well while the direct restoration results vary with the delay but improve with larger equalizer orders.
Benefits from U.S. Monetary Policy Experimentation in the Days of Samuelson and Solow and Lucas

A policy maker knows two models of ination-unemplo yment dynamics. One implies an exploitable trade-o, the other does not. The policy maker’s prior probability over the two models is part of his state vector. Bayes’ law converts the prior probability into a posterior probability at each date and gives the policy maker an incentive to experiment. For two models calibrated to U.S. data through the early 1960s, we isolate the component of government policy that is due to experimentation by comparing the outcomes from two Bellman equations, the rst of which ‘experiments and learns’, the second of which ‘learns but doesn’t experiment’. We interpret the second as an ‘anticipated utility’ model and study how well its outcomes approximate those from the ‘experiment and learn’ Bellman equation. The approximation is good. For our calibrations, the benets from purposeful experimentation are small.
Pulsed-inductive thruster

The Flux-Coil-Generated, Field-Reversed Configuration Experiment (FCX) at Tri Alpha Energy, Inc. (TAE) requires an initial source of plasma, from which the FRC is formed. This paper details the design, simulation, and performance measured for a new set of PITs developed for the FCX. The simulation solves coupled differential equations for the circuit, plasma parameters, including formation and acceleration. The PIT construction involves: 5 gas valves, a 2-stage Marx generator capacitor bank, a low-inductance parallel-plate transmission line and a H.V. feedthrough. The system delivers a 2.5 us, 1/4 period pulse and 1 Ohm impedance. Measurements at the surface of the PIT indicate: n = 1014-1015 cm-3, Ti = 30 eV, Vi = 100 eV. Measurements 1-m downstream indicate: n = 1012-1014 cm-3, temperature, Ti = 10 eV, and total plasma energy content, Wp = 30 J, which are adequate for the FCX.
A finite element multiscale capability for nonlinear quasistatic stress analysis

Failure modeling is inherently a multi length scale phenomenon that requires a failure model and a computational method that solves for stress/strain gradients at interesting locations. Focusing on the computational method, we recognize that the mesh resolution must be relatively fine in regions where failure is expected and relatively coarse elsewhere. Furthermore, in some modeling approaches the topology in the structural model is different than that required in the fine scale model where failure is to be predicted. This necessarily precludes approaches such as h-adaptivity. We are therefore led to consider multiscale approaches to solve these problems.This work describes an approach to solve multiple (a reference scale and fine scale) coupled boundary value problems for the purpose of nonlinear quasistatic stress analysis. Two examples are included: one example illustrates the multiscale solution strategy to perform quasistatic stress analysis and the other demonstrates the computational beginnings of the ability to model material failure.
Use of coupled passivants and consolidants on calcite mineral surfaces

Deterioration of monuments, buildings, and works of art constructed of carbonate-based stone potentially can be arrested by applying a combination of chemical passivants and consolidants that prevent hydrolytic attack and mechanical weakening. The authors used molecular modeling and laboratory synthesis to develop an improved passivating agent for the calcite mineral surface based on binding strength and molecular packing density. The effectiveness of the passivating agent with and without a linked outer layer of consolidant against chemical weathering was determined through leaching tests conducted with a pH-stat apparatus at pH 5 and 25 C. For the range of molecules considered, modeling results indicate that the strongest-binding passivant is the trimethoxy dianionic form of silylalkylaminocarboxylate (SAAC). The same form of silylalkylphosphonate (SAP) is the second strongest binder and the trisilanol neutral form of aminoethylaminopropylsilane (AEAPS) is ranked third. Short-term leaching tests on calcite powders coated with the trisilanol derivative of SAAC, the triethoxy neutral form of SAP, and the trimethoxy neutral form of AEAPS show that the passivant alone does not significantly slow the dissolution rate. However, all passivants when linked to the sol consolidant result in decreased rates. Combined AEAPS plus consolidant results in a coating that performs better than the commercial product Conservare{reg_sign} OH and at least as well as Conservare{reg_sign} H. The modeling results indicate that there may be a threshold binding energy for the passivant above which the dissolution rate of calcite is actually enhanced. More strongly-binding passivants may aid in the dissolution mechanism or dissociate in aqueous solution exposing the calcite surface to water.
Explaining Variation in Takeover: Defenses Blame the Lawyers

Traditional law and economics scholarship predicts that no companies will adopt takeover defenses prior to IPOs, because defenses increase agency costs between shareholders and managers, and reduce IPO proceeds. In fact, data from 357 IPOs in the 1990s show that many companies adopt defenses prior to IPOs. Even more puzzling for conventional scholarship, defenses vary widely at the IPO stage. Analysis shows that more of this variation in defenses can be explained by characteristics of law firms advising owner-managers than by traditional theories about defenses. Among other findings: (1) Companies advised by larger law firms with more takeover experience adopt more defenses; (2) In 1991-92, companies with Silicon Valley lawyers adopted almost no defenses; by 1998, Silicon Valley lawyers' clients were as likely to use defenses as clients of other lawyers; (3) Companies with high quality underwriters and venture capital backing adopt more defenses; (4) The overall rate of defense adoption increased in the 1990s. Together, these findings provide strong evidence that lawyers determine key terms in the "corporate contract", due to agency costs between owner-managers and their lawyers.
Why don't Lenders Finance High-Return Technological Change in Developing-Country Agriculture?

Most of the literature attributes credit constraints in small-farm developing-country agriculture to the variability of returns to investment in this sector. But the literature does not fully explain lenders' reluctance to finance investments in technologies that provide both higher average and less variable returns. This article develops an information-theoretic credit market model with endogenous technology choice. The model demonstrates that lenders may refuse to finance any investment in a riskless high-return technology—regardless of the interest rate they are offered—when they are imperfectly informed about loan applicants' time preferences and, therefore, about their propensities to default intentionally in order to finance current consumption. Copyright 2001, Oxford University Press.
The syntheses, structures, bonding, and reactivity of cyclopentadienylaluminum(III) derivatives

Abstract Cyclopentadienylaluminum compounds have been a curiosity due to the ring-slipped structures they exhibit and due to their highly fluxional nature, which has prevented the freezing out of discrete solution structures on the NMR time scale. Lately, increased attention toward these compounds in the form of molecular structure determinations, theoretical calculations, and 27Al-NMR spectroscopic measurements is providing a clearer picture of the bonding between the aluminum and its cyclopentadienyl ring(s). A variety of ring coordination geometries (η1, η2, η3, η5) have been identified in molecular structures of these compounds, and although theoretical calculations reveal very small energy differences between different haptotropes, consistent with their highly fluxional behavior in solution, there is close agreement between the calculated ground state geometries for the compounds and the geometries they exhibit in the solid state and in solution. Theory and experiment reveal a delicate balance of covalent π-interactions and ionic interactions between the aluminum and its cyclopentadienyl ring. Although the balance is easily tipped by steric effects, some structural trends are emerging. The solution 27Al-NMR chemical shifts of cyclopentadienylaluminum compounds are surprisingly diagnostic of their geometries, exhibiting a strong correlation with coordination numbers that take into account the hapticity of the cyclopentadienyl ring.
Diamond—Ceramic Coating of the Future

On etudie le depot chimique en phase vapeur et la croissance cristalline de revetement de diamant
"No-Till" Farming Is a Growing Practice

Most U.S. farmers prepare their soil for seeding and weed and pest control through tillage—plowing operations that disturb the soil. Tillage practices affect soil carbon, water pollution, and farmers’ energy and pesticide use, and therefore data on tillage can be valuable for understanding the practice’s role in reaching climate and other environmental goals. In order to help policymakers and other interested parties better understand U.S. tillage practices and, especially, those practices’ potential contribution to climate-change efforts, ERS researchers compiled data from the Agricultural Resource Management Survey and the National Resources Inventory-Conservation Effects Assessment Project’s Cropland Survey. The data show that approximately 35.5 percent of U.S. cropland planted to eight major crops, or 88 million acres, had no tillage operations in 2009.
A Game-Theoretic Interpretation of Sun Tzu's The Art of War"

Over twenty five hundred years ago the Chinese scholar Sun Tzu, in The Art of War, attempted to codify the general strategic character of conflict and, in the process, offer practical advice about how to win military conflicts. His advice is credited with having greatly influenced both Japanese military and business practices, as well as Mao Tse-Tung's approach to conflict and revolution. The question, however, is whether or to what extent Sun Tzu anticipated the implications of the contemporary theory of conflict -- game theory. The thesis of this essay is that he can be credited with having anticipated the concepts of dominant, minmax, and mixed strategies, but that he failed to intuit the full implications of the notion of equilibrium strategies. Thus, while he offers a partial resolution of "he-thinks-that-I-think" regresses, his advice remains vulnerable to a more complete strategic analysis.
INFORMALITY: CAUSES, CONSEQUENCES AND POLICY RESPONSES

A stylized prediction of the development economics discourse is that informality will disappear with development, and yet in the last 20 years conventional measures of informality, far from declining, have either remained stagnant or have actually increased. This includes countries such as India where economic growth has been at historically high levels. What exactly is informality and what are its magnitudes and trends? What are the causes of informality and why is it not decreasing as predicted by standard theories of development? What are the consequences for inclusive economic growth of a large and increasing informal sector? What are feasible and desirable policy responses to informality? These are the questions that motivate this broad based overview of informality. The questions will be addressed based on recent and ongoing research on India and globally.
UNIVERSAL LABELING ALGEBRAS AS INVARIANTS OF LAYERED GRAPHS

Abstract In this work we will study the universal labeling algebra A ( Γ ) , a related algebra B ( Γ ) , and their behavior as invariants of layered graphs. We will introduce the notion of an upper vertex-like basis, which allows us to recover structural information about the graph Γ from the algebra B ( Γ ) . We will use these bases to show that several classes of layered graphs are uniquely identified by their corresponding algebras B ( Γ ) .
Sea ice identification using dual-polarized Ku-band scatterometer data

This paper describes a classification algorithm using dual-polarized scatterometer measurements to identify the edge of the sea ice cover. The distinct polarization scattering signatures of sea ice and open water are discussed and illustrated with the dual-polarized radar measurements from the Seasat-A scatterometer (SASS). The analysis of SASS data suggests that the ratio of vertical and horizontal polarization backscatter, denoted as the copol ratio, is a useful discriminator of sea ice and open ocean. A simple classification algorithm using the thresholds of the copol ratio and backscatter levels is proposed. The feasibility of this algorithm is demonstrated using the SASS data from the single-sided, dual-polarization mode. The results indicate that the dual-polarized measurements from the NASA scatterometer (NSCAT) can be used to produce routine maps of sea ice edges.
A GALAXY PHOTOMETRIC REDSHIFT CATALOG FOR THE SLOAN DIGITAL SKY SURVEY DATA RELEASE 6

We present and describe a catalog of galaxy photometric redshifts (photo-z's) for the Sloan Digital Sky Survey (SDSS) Data Release 6 (DR6). We use the neural network (NN) technique to calculate photo-z's and the nearest neighbor error (NNE) method to estimate photo-z errors for ~77 million objects classified as galaxies in DR6 with r < 22. The photo-z and photo-z error estimators are trained and validated on a sample of ~640,000 galaxies that have SDSS photometry and spectroscopic redshifts measured by SDSS, the Two Degree Field, the SDSS Luminous Red Galaxy and Quasi-stellar Object Survey (2SLAQ), the Canada-France Redshift Survey (CFRS), the Canadian Network for Observational Cosmology Field Galaxy Survey (CNOC2), the Team Keck Redshift Survey (TKRS), the Deep Extragalactic Evolutionary Probe (DEEP), and DEEP2. For the two best NN methods we have tried, we find that 68% of the galaxies in the validation set have a photo-z error smaller than σ68 = 0.021 or 0.024. After presenting our results and quality tests, we provide a short guide for users accessing the public data.
Contour Extraction of Drosophila Embryos

Contour extraction of Drosophila (fruit fly) embryos is an important step to build a computational system for matching expression pattern of embryonic images to assist the discovery of the nature of genes. Automatic contour extraction of embryos is challenging due to severe image variations, including 1) the size, orientation, shape, and appearance of an embryo of interest; 2) the neighboring context of an embryo of interest (such as nontouching and touching neighboring embryos); and 3) illumination circumstance. In this paper, we propose an automatic framework for contour extraction of the embryo of interest in an embryonic image. The proposed framework contains three components. Its first component applies a mixture model of quadratic curves, with statistical features, to initialize the contour of the embryo of interest. An efficient method based on imbalanced image points is proposed to compute model parameters. The second component applies active contour model to refine embryo contours. The third component applies eigen-shape modeling to smooth jaggy contours caused by blurred embryo boundaries. We test the proposed framework on a data set of 8,000 embryonic images, and achieve promising accuracy (88 percent), that is, substantially higher than the-state-of-the-art results.
On scheduling real-time traffic under controlled load service in an integrated services Internet

The controlled load service defined within the IETF's Integrated Services architecture for quality-of-service (QoS) in the Internet requires source nodes to regulate their traffic while the network, in combination with an admission control strategy, provides a guarantee of performance equivalent to that achieved in a lightly loaded network. Packets sent in violation of the traffic contract are marked so that the network may assign them a lower priority in the use of bandwidth and buffer resources. In this paper, we define the requirements of a scheduler serving packets belonging to the controlled load service and present a novel scheduler that exactly achieves these requirements. In this set of requirements, besides efficiency and throughput, we include an additional important requirement to bound the additional delay of unmarked packets caused due to the transmission of marked packets while dropping as few marked packets as possible. Without such a bound, unmarked packets that are in compliance with the traffic contract are not likely to experience delays consistent with that in a lightly loaded network. For any given desired bound α on this additional delay, we present the CL(α) scheduler which achieves the bound while also achieving a per-packet work complexity of O(1) with respect to the number of flows. We provide an analytical proof of these properties of the CL(α) scheduler, and we also verify this with simulation using real traces of video traffic. The scheduler presented here may be readily adapted for use in scheduling flows with multi-level priorities such as in some real-time video streams, as well as in other emerging service models of the Internet that mark packets to identify drop precedences.
Some contributions to aerodynamic theory for vertical-axis wind turbines

A review and modest extensions are described of quasisteady aerodynamic theory for performance prediction on Darrieus-type turbines. Results are given for both parallel-axis and curved-blade configurations. Blade stall and variable inflow are neglected; it is hypothesized that unsteady effects support the former approximation down to lower values of tip-speed ratio than hitherto believed. Both profile and induced drag are included, and their influences on power and downwind force are expressed in terms of elliptic integrals. Comparisons are presented with power data from the Sandia 2-m turbine. Three values of profile drag coefficient are employed, and it is argued that numbers in the range CD() =0.015-0.017 are most appropriate to the example chosen. Finally, a linearized analysis of unsteady flow effects on performance is summarized. Calculations suggest that they may be larger than might be expected in view of the low operating reduced frequencies of these machines.
Efficient attributes for anonymous credentials

We extend the Camenisch-Lysyanskaya anonymous credential system such that selective disclosure of attributes becomes highly efficient. The resulting system significantly improves upon existing approaches, which suffer from a linear complexity in the total number of attributes. This limitation makes them unfit for many practical applications, such as electronic identity cards. Our system can incorporate an arbitrary number of binary and finite-set attributes without significant performance impact. Our approach folds all such attributes in a single attribute base and, thus, boosts the efficiency of all proofs of possession. The core idea is to encode discrete binary and finite-set attribute values as prime numbers. We use the divisibility property for efficient proofs of their presence or absence. We additionally contribute efficient methods for conjunctions and disjunctions. The system builds on the Strong-RSA assumption alone. We demonstrate the applicability and performance improvements of our method in realistic application scenarios, such as, electronic identity cards and complex/structured credentials. Our method has crucial advantages in devices with restricted computational capabilities, such as smartcards and cell phones.
Clinical effectiveness of an aerosol contraceptive foam

Abstract Vaginal contraceptive foam was used by 2,932 women for 28,322 cycles. The pregnancy rate, 3.98 pregnancies/100 women-years, was relatively low for a vaginal contraceptive. This degree of effectiveness is attributed to patient instruction and motivation and frequent contact between patient and clinic staff.
Chelation-controlled ester-derived titanium enolate aldol reaction: diastereoselective syn-aldols with mono- and bidentate aldehydes

A chelation-controlled and highly diastereoselective synthesis of syn-aldols is described. Aldol reaction of (S)-valinol-derived ester with a variety of aldehydes proceeded with high syn-diastereoselectivities (up to 99:1) and isolated yields (94%).
Generalized tardiness bounds for global multiprocessor scheduling

We consider the issue of deadline tardiness under global multiprocessor scheduling algorithms. We present a general tardiness-bound derivation that is applicable to a wide variety of such algorithms (including some whose tardiness behavior has not been analyzed before). Our derivation is very general: job priorities may change rather arbitrarily at runtime, capacity restrictions may exist on certain processors, and, under certain conditions, non-preemptive regions are allowed. Our results show that, with the exception of static-priority algorithms, most global algorithms considered previously have bounded tardiness. In addition, our results provide a simple means for checking whether tardiness is bounded under newly-developed algorithms.
Measuring network effects on trade: Are Japanese affiliates distinctive?

Abstract This paper examines network effects on trade by comparing the trade patterns of foreign affiliates in the United States with the trade patterns of US-owned firms. The evidence strongly supports the following hypotheses: (1) foreign affiliates behave differently from US firms in their trade patterns; (2) in particular, foreign affiliates display strong home biases in their trade patterns; and (3) among the foreign affiliates, Japanese affiliates demonstrate by far the strongest home bias in their trade patterns. Controlling for income and distance effects, foreign affiliates from Canada, France, Germany, the Netherlands and Switzerland traded on average 17 times more with their respective home countries and those from the United Kingdom traded 30 times more with the United Kingdom, while Japanese affiliates traded a whopping 130 times more with Japan. J. Japanese Int. Economies 19 (2) (2005) 194–214.
A HYBRID MODE MODEL OF THE BLAZHKO EFFECT, SHOWN TO ACCURATELY FIT KEPLER DATA FOR RR Lyr

The waveform for Blazhko stars can be substantially different during the ascending and descending parts of the Blazhko cycle. A hybrid model, consisting of two component oscillators of the same frequency, is proposed as a means to fit the data over the entire cycle. One component exhibits a sawtooth-like velocity waveform while the other is nearly sinusoidal. One method of generating such a hybrid is presented: a nonlinear model is developed for the first overtone mode, which, if excited to large amplitude, is found to drop strongly in frequency and become highly non-sinusoidal. If the frequency drops sufficiently to become equal to the fundamental frequency, the two can become phase locked and form the desired hybrid. A relationship is assumed between the hybrid mode velocity and the observed light curve, which is approximated as a power series. An accurate fit of the hybrid model is made to actual Kepler data for RR Lyr. The sinusoidal component may tend to stabilize the period of the hybrid which is found in real Blazhko data to be extremely stable. It is proposed that the variations in amplitude and phase might result from a nonlinear interaction with a third mode, possibly a nonradial mode at 3/2 the fundamental frequency. The hybrid model also applies to non-Blazhko RRab stars and provides an explanation for the light curve bump. A method to estimate the surface gravity is also proposed.
Biological chemistry of organotin compounds: Interactions and dealkylation by dithiols

In this paper, we review our past and current efforts toward the elucidation of the biological chemistry of organotin compounds. In particular, we cover two prominent aspects of organotin compounds: their reactivity toward biological dithiols, and their degradation (or metabolization) mechanism using a combination of experimental and computational techniques.
Are artworks more like people than artifacts? Individual concepts and their extensions.

This paper examines people’s reasoning about identity continuity (i.e., how people decide that a particular object is the same object over time) and its relation to previous research on how people value one-of-a-kind artifacts, such as artwork. We propose that judgments about the continuity of artworks are related to judgments about the continuity of individual persons because art objects are seen as physical extensions of their creators. We report a reanalysis of previous data and the results of two new empirical studies that test this hypothesis. The first study demonstrates that the mere categorization of an object as “art” versus “a tool” changes people’s intuitions about the persistence of those objects over time. In a second study, we examine some conditions that may lead artworks to be thought of as different from other artifacts. These observations inform both current understanding of what makes some objects one-of-a-kind as well as broader questions regarding how people intuitively think about the persistence of human agents.
On Computational Methods for Crashworthiness

The evolution of computational methods for crashworthiness and related fields is described and linked with the decreasing cost of computational resources and with improvements in computation methodologies. The latter includes more effective time integration procedures and more efficient elements. Some recent developments in methodologies and future trends are also summarized. These include multi-time step integration (or subcycling), further improvements in elements, adaptive meshes, and the exploitation of parallel computers.
Guidelines for colonoscopy surveillance after polypectomy: A consensus update by the US Multi-Society Task Force on Colorectal Cancer and the American Cancer Society

Adenomatous polyps are the most common neoplastic findings uncovered in people who undergo colorectal screening or have a diagnostic workup for symptoms. It was common practice in the 1970s for these patients to have annual follow-up surveillance examinations to detect additional new adenomas as well as missed synchronous adenomas. As a result of the National Polyp Study report in 1993, which demonstrated clearly in a randomized design that the first postpolypectomy examination could be deferred for 3 years, guidelines published by a gastrointestinal consortium in 1997 recommended that the first follow-up surveillance be 3 years after polypectomy for most patients. In 2003, these guidelines were updated, colonoscopy was recommended as the only follow-up examination, and stratification at baseline into lower and higher risk for subsequent adenomas was suggested. The 1997 and 2003 guidelines dealt with both screening and surveillance. However, it has become increasingly clear that postpolypectomy surveillance is now a large part of endoscopic practice, draining resources from screening and diagnosis. In addition, surveys have demonstrated that a large proportion of endoscopists are conducting surveillance examinations at shorter intervals than recommended in the guidelines. In the present paper, a careful analytic approach was designed addressing all evidence available in the literature to delineate predictors of advanced pathology, both cancer and advanced adenomas, so that patients can be more definitely stratified at their baseline colonoscopy into those at lower or increased risk for a subsequent advanced neoplasia. People at increased risk have either three or more adenomas, or high-grade dysplasia, or villous features, or an adenoma ≥1 cm in size. It is recommended that they have a 3-year follow-up colonoscopy. People at lower risk who have one or two small (<1 cm) tubular adenomas with no high-grade dysplasia can have a follow up in 5 to 10 years, whereas people with hyperplastic polyps only should have a 10-year follow up as average-risk people. Recent papers have reported a significant number of missed cancers by colonoscopy. However, high-quality baseline colonoscopy with excellent patient preparation and adequate withdrawal time should minimize this and reduce clinicians' concerns. These guidelines were developed jointly by the US Multi-Society Task Force on Colorectal Cancer and the American Cancer Society to provide a broader consensus and thereby increase utilization of the recommendations by endoscopists. Adoption of these guidelines nationally can have a dramatic impact on shifting available resources from intensive surveillance to screening. It has been shown that the first screening colonoscopy and polypectomy produces the greatest effects on reducing the incidence of colorectal cancer in patients with adenomatous polyps.
Launch Vehicle Dynamic and Control Effects from Solid Rocket Motor Slag Ejection

The effects of the ejection of slag from a Titan IV solid rocket motor upgrade (SRMU) are analyzed for the maximum dynamic pressure time. It is assumed that the 2500 Ibs of slag on board at that time is ejected, and the corresponding thrust perturbation is determined using existing theory for the discharge of an inert body. The slag ejection event causes sharp thrust transients during blockage of the nozzle throat and blow-down of the motor internal pressure. Control simulations indicate a worst-case SRMU gimbal angle change of 0.51 deg during the event, and small-amplitude limit cycles after the excitation. An aeroelastic analysis yields yaw shear loads and bending moments as high as 13600 Ibf and 5.1x 106 Ibf-in, respectively, at the aft end of the vehicle. It is shown that the degree of the nozzle throat blockage primarily defines the lateral load magnitudes. The Titan IV has adequate structural and control margins, and slag ejection does not pose a concern for its missions. Nomenclature A* =
Structures and self-activating photoluminescent properties of Sr3−xAxGaO4F (A=Ba, Ca) materials

Abstract The synthesis, structures and photoluminescent properties of mixed oxyfluorides of the type Sr 3− x A x GaO 4 F are compared to Sr 3− x A x AlO 4 F ( A =Ca, Ba) materials. In these compounds the F − and O 2− ions are ordered and located on two distinct crystallographic sites. When substituting Sr 2+ by Ba 2+ and Ca 2+ , we find in Sr 3− x A x GaO 4 F materials an ordering of the alkaline earth cations over the two crystallographic sites. The amount of Ba 2+ ions that can be substituted into Sr 3− x A x GaO 4 F is x ≤1.2, which is slightly more than can be incorporated into the previously reported Al-analog Sr 3− x A x AlO 4 F ( x =1.0). Conversely, the amount of Ca 2+ ions that can be substituted into Sr 3− x Ca x GaO 4 F ( x =0.3) is significantly less than in Sr 3− x Ca x AlO 4 F ( x =1.0). A post-synthesis reduction step causes these materials to exhibit self-activating broad band photoluminescence where the emitted colors vary with the amount of ions substituted into the host lattice.
Simultaneous localization and mapping with detection and tracking of moving objects

Both simultaneous localization and mapping (SLAM) and detection and tracking of moving objects (DTMO) play key roles in robotics and automation. For certain constrained environments, SLAM and DTMO are becoming solved problems, but for robots working outdoors and at high speeds, SLAM and DTMO are still incomplete. In earlier works, SLAM and DTMO are treated as two separate problems. In fact, they can be complementary to one another. In this paper, we present a new method to integrate SLAM and DTMO to solve both problems simultaneously for both indoor and outdoor applications. The results of experiments carried out with CMU Navlab8 and Navlab11 vehicles with the maximum speed of 45 mph in crowded urban and suburban areas verify the described work.
A parallel second-order adaptive mesh algorithm for incompressible flow in porous media

In this paper we present a second-order accurate adaptive algorithm for solving multiphase, incompressible ows in porous media. We assume a multiphase form of Darcy's law with relative permeabilities given as a function of the phase saturation. The remaining equations express conservation of mass for the uid constituents. In this setting the total velocity, dened to be the sum of the phase velocities, is divergence-free. The basic integration method is based on a total-velocity splitting approach in which we solve a second-order elliptic pressure equation to obtain a total velocity. This total velocity is then used to recast component conservation equations as nonlinear hyperbolic equations. Our approach to adaptive renement uses a nested hierarchy of logically rectangular grids with simultaneous renement of the grids in both space and time. The integration algorithm on the grid hierarchy is a recursive procedure in which coarse grids are advanced in time, ne grids are advanced multiple steps to reach the same time as the coarse grids and the data at dierent levels are then synchronized. The single grid algorithm is described briey, but the emphasis here is on the time-stepping procedure for the adaptive hierarchy. Numerical examples are presented to demonstrate the algorithm's accuracy and convergence properties and to illustrate the behavior of the method.