cssi/SciSciGPT-SciSciNet huggingface dataset:
Using decision lists to construct interpretable and parsimonious treatment regimes

A treatment regime formalizes personalized medicine as a function from individual patient characteristics to a recommended treatment. A high-quality treatment regime can improve patient outcomes while reducing cost, resource consumption, and treatment burden. Thus, there is tremendous interest in estimating treatment regimes from observational and randomized studies. However, the development of treatment regimes for application in clinical practice requires the long-term, joint effort of statisticians and clinical scientists. In this collaborative process, the statistician must integrate clinical science into the statistical models underlying a treatment regime and the clinician must scrutinize the estimated treatment regime for scientific validity. To facilitate meaningful information exchange, it is important that estimated treatment regimes be interpretable in a subject-matter context. We propose a simple, yet flexible class of treatment regimes whose members are representable as a short list of if-then statements. Regimes in this class are immediately interpretable and are therefore an appealing choice for broad application in practice. We derive a robust estimator of the optimal regime within this class and demonstrate its finite sample performance using simulation experiments. The proposed method is illustrated with data from two clinical trials.
Non-Boltzmann dynamics in networks of spiking neurons

Networks of spiking neurons in which spikes are fired as a Poisson process are studied. The state of a cell is determined by the instantaneous firing rate, and in the limit of high firing rates the model reduces to that studied by Hopfield. The inclusion of spiking results in several features including a noise-induced asymmetry between on and off states, and probability currents which destroy the usual description of network dynamics in terms of energy surfaces. Taking account of spikes also allows calibration of network parameters such as synaptic weights against experiments on real synapses. Realistic forms of the post-synaptic response alter the network dynamics, which suggests a dynamical learning mechanism. >
Sparse projections of medical images onto manifolds

Manifold learning has been successfully applied to a variety of medical imaging problems. Its use in real-time applications requires fast projection onto the low-dimensional space. To this end, out-of-sample extensions are applied by constructing an interpolation function that maps from the input space to the low-dimensional manifold. Commonly used approaches such as the Nystrom extension and kernel ridge regression require using all training points. We propose an interpolation function that only depends on a small subset of the input training data. Consequently, in the testing phase each new point only needs to be compared against a small number of input training data in order to project the point onto the low-dimensional space. We interpret our method as an out-of-sample extension that approximates kernel ridge regression. Our method involves solving a simple convex optimization problem and has the attractive property of guaranteeing an upper bound on the approximation error, which is crucial for medical applications. Tuning this error bound controls the sparsity of the resulting interpolation function. We illustrate our method in two clinical applications that require fast mapping of input images onto a low-dimensional space.
Distance to market and search costs in an African maize market

Farm-gate buying by small itinerant buyers is the dominant mode of primary marketing in Tanzania's maize market. This paper estimates the effect of household distance to market on maize farm-gate prices, and the extent to which seasonally determined search costs can explain price variations between the lean and the harvest seasons using data from the most recent Tanzania Household Budget Survey (2007). The author observes that greater distance to market depresses farm-gate prices but that it is a relatively modest effect, and that this effect is pro-cyclical in that it is stronger during the harvest season when prices are lowest. The paper discusses the latter result with reference to search costs as an explanatory factor. It also briefly places the findings in the context of Tanzania's food security patterns, making a link between food insecurity and high search costs. The main policy conclusion is that coordinating mechanisms such as village market places (in parallel with farm-gate buying) may reduce transaction costs in rural markets.
Shortest-Path Queries in Planar Graphs on GPU-Accelerated Architectures

We develop an efficient parallel algorithm for answering shortest-path queries in planar graphs and implement it on a multi-node CPU-GPU clusters. The algorithm uses a divide-and-conquer approach for decomposing the input graph into small and roughly equal subgraphs and constructs a distributed data structure containing shortest distances within each of those subgraphs and between their boundary vertices. For a planar graph with n vertices, that data structure needs O(n) storage per processor and allows queries to be answered in \(O(n^{1/4})\) time.
Dovetail: Stronger Anonymity In Next-generation Internet Routing

Given current research initiatives advocating “clean slate” Internet designs, researchers have the opportunity to design an internetwork layer routing protocol that provides efficient anonymity by decoupling identity from network location. Prior work in anonymity for the next-generation Internet fully trusts the user’s ISP. We propose Dovetail, which provides anonymity against an active attacker located at any single point within the network, including the user’s ISP. A major design challenge is to provide this protection without including an applicationlayer proxy in data transmission. We address this in path construction by using a matchmaker node (an end host) to overlap two path segments at a dovetail node (a router). The dovetail then trims away part of the path so that data transmission bypasses the matchmaker. We develop a systematic mechanism to measure the topological anonymity of our designs, and we demonstrate their privacy and efficiency by Internet-scale simulations at the AS-level.
Propagation through trapped sets and semiclassical resolvent estimates

Let \(P = -{h}^{2}\Delta + V (x)\), \(V \in {C}_{0}^{\infty }({\mathbb{R}}^{n})\).We are interested in semiclassical resolvent estimates of the form $$ \|\chi {(P - E - i0)}^{-1}{\chi \|}_{{L}^{2}({\mathbb{R}}^{n})\rightarrow {L}^{2}({\mathbb{R}}^{n})} \leq \frac{a(h)}{h} ,\qquad h \in (0,{h}_{0}],$$ (1) for E > 0, \(\chi \in {C}^{\infty }({\mathbb{R}}^{n})\) with \(\vert \chi (x)\vert \leq \langle {x\rangle }^{-s}\), s > 1 ∕ 2. We ask: how is the function a(h) for which (1) holds affected by the relationship between the support of \(\chi \) and the trapped set at energy E, defined by $${K}_{E} =\{ \alpha \in {T}^{{_\ast}}{\mathbb{R}}^{n}: \exists C > 0,\forall t > 0,\vert \exp (t{H}_{p})\alpha \vert \leq C\}?$$ Here \(p = \vert \xi {\vert }^{2} + V (x)\) and \({H}_{p} = 2\xi \cdot {\nabla }_{x} -\nabla V \cdot {\nabla }_{\xi }\).
Pions and neutrinos as probes of the nucleon and nuclear few body system

A number of studies of few-body nucleon and nuclear systems are being pursued at LAMPF using pions and neutrinos as probes. These include: a high-statistics measurement of the cross section for the reaction π + p → π + π 0 p to determine the I = 2 π π scattering length; precision measurements of the π- p charge exchange cross section in the region of the Δ; measurements of the cross section for the (π ±, π ± p) from D, 3He, and 4He as tests of charge symmetry and reaction mechanisms; measurements of the π + p cross section below the Δ; and studies of vp elastic scattering at low Q 2 to determine the quark content of the proton spin. Some of these experiments acquired data last year, while others are presently running. LAMPF, the highest power proton accelerator in the world, is presently in the midst of its 1993 production run.
MARKET POWER AND EFFICIENCY IN A SEARCH MODEL

We build a theoretical model to study the welfare effects and resulting policy implications of firms’ market power in a frictional labor market. Our environment has two main characteristics: wages play a role in allocating labor across firms and there is a finite number of agents. We find that the decentralized equilibrium is inefficient and that the firms’ market power results in the misallocation of workers from the high to the low-productivity firms. A minimum wage forces the low-productivity firms to increase their wage, leading them to hire even more often thereby exacerbating the inefficiencies. Moderate unemployment benefits can increase welfare because they limit firms’ market power by improving the workers’ outside option.
Goals and Social Comparisons Promote Walking Behavior

The effectiveness of a pedometer intervention was affected by manipulating the goals given to participants and by providing social comparison feedback about how participants' performance compared with others. In study 1 (n= 148), university staff members received a low, medium, or high walking goal (10%, 50%, or 100% increase over baseline walking). Participants walked 1358 more steps per day (95% confidence interval [CI], 729, 1985), when receiving a high goal than when receiving a medium goal, but a medium goal did not increase walking relative to a low goal (554 more steps; 95% CI, -71,1179). In study 2 (n= 64), participants received individual feedback only or individual plus social comparison feedback. Participants walked 1120 more steps per day (95% CI, 538, 1703) when receiving social comparison feedback than when receiving only individual feedback. Goals and the performance of others act as reference points and influence the effect that pedometer feedback has on walking behavior, illustrating the applicability of the principles of behavioral economics and social psychology to the design of health behavior interventions.
Update on Specifications for NIF Ignition Targets, and Their Rollup into an Error Budget

Targets intended to produce ignition on NIF are being simulated and the simulations are used to set specifications for target fabrication. Recent design work has focused on designs that assume only...
Regulatory T Cells in Tumor-Associated Tertiary Lymphoid Structures Suppress Anti-tumor T Cell Responses

Infiltration of regulatory T (Treg) cells into many tumor types correlates with poor patient prognoses. However, mechanisms of intratumoral Treg cell function remain to be elucidated. We investigated Treg cell function in a genetically engineered mouse model of lung adenocarcinoma and found that Treg cells suppressed anti-tumor responses in tumor-associated tertiary lymphoid structures (TA-TLSs). TA-TLSs have been described in human lung cancers, but their function remains to be determined. TLSs in this model were spatially associated with >90% of tumors and facilitated interactions between T cells and tumor-antigen-presenting dendritic cells (DCs). Costimulatory ligand expression by DCs and T cell proliferation rates increased in TA-TLSs upon Treg cell depletion, leading to tumor destruction. Thus, we propose that Treg cells in TA-TLSs can inhibit endogenous immune responses against tumors, and targeting these cells might provide therapeutic benefit for cancer patients.
A product space perspective on structural change in Morocco

Drawing on international trade data, this paper uses the product space approach to analyze changes in Morocco’s goods exports in 1990–2010 and future export priorities. The level of Morocco’s gross domestic product and its moderate growth match the predictions of product space analysis, informed by changes in the income potential of Morocco’s export basket, reflecting relatively strong capabilities (a high density) in products with relatively low potentials in income and diversification. Morocco’s peripheral position in the product space map matches its slow growth and points to the difficulty of diversification into more sophisticated products. Encouraging changes since 1990 include the development of a revealed comparative advantage for medium- and high-tech manufactures, which in 2010 represented around 40 percent of total goods exports. However, the number of goods involved is relatively small and this transformation has not sufficed to raise per capita growth to the average for middle-income countries. Export projections up to 2025 suggest that future developments will follow the trends of the past. Among sectors, high growth is likely for phosphate-based fertilizer exports. However, like edible oil products, which also may grow rapidly, phosphates are hampered by low income and diversification potentials. Along with various other manufactured products, electronics and the automotive industry are promising sectors that may offer more lasting positive contributions to Morocco’s future development. Beyond goods, Morocco’s policy makers should also consider the potential contributions of service exports, which in recent years have enjoyed rapid growth.
The relationship between hope and patient activation in consumers with schizophrenia: Results from longitudinal analyses

Hope (goal-directed thinking) and patient activation (knowledge and skills to manage one's illness) are both important in managing chronic conditions like schizophrenia. The relationship between hope and patient activation has not been clearly defined. However, hope may be viewed as a foundational, motivating factor that can lead to greater involvement in care and feelings of efficacy. The purpose of the present study was to understand the prospective relationship between hope and patient activation in a sample of adults with schizophrenia (N=118). This study was a secondary data analysis from a study on Illness Management and Recovery (IMR) - a curriculum-based approach to schizophrenia self-management. Data were collected at baseline (prior to any intervention), and at 9 and 18-month follow-up. As predicted, hope and patient activation were significantly related with each other, showing large positive concurrent correlations. Demographics and background characteristics were not significantly related to patient activation or hope. Longitudinal analyses found no specific directional effect, yet suggested that hope and patient activation mutually influence each other over time. Our findings add flexibility in designing recovery-based interventions - fostering hope may not be a pre-requisite for activating consumers to be more involved in their own care.
Vortex equations governing the fractional quantum Hall effect

An existence theory is established for a coupled non-linear elliptic system, known as “vortex equations,” describing the fractional quantum Hall effect in 2-dimensional double-layered electron systems. Via variational methods, we prove the existence and uniqueness of multiple vortices over a doubly periodic domain and the full plane. In the doubly periodic situation, explicit sufficient and necessary conditions are obtained that relate the size of the domain and the vortex numbers. For the full plane case, existence is established for all finite-energy solutions and exponential decay estimates are proved. Quantization phenomena of the magnetic flux are found in both cases.
Measuring Monetary Policy in Open Economies

The paper extends Bernanke and Mihov's [6] closed-economy strategy for identification of monetary policy shocks to open-economy settings, accounting for the simultaneity between interest-rate and exchange-rate innovations. The methodology allows a separate treatment of two distinct monetary policy shocks, one that operates through open market operations, and another one that takes place through interventions in the foreign exchange market. Implementation of this strategy to the case of Argentina provides the stylized facts necessary to choose among competing theoretical models of this economy. In addition to studying the effects of monetary policy innovations, the present study sheds light on the endogenous component of monetary policy. In this regard, the paper finds that, notwithstanding the relative stability of the exchange rate and the accumulation of large amounts of international reserves, the central bank in Argentina has been far from absorbing balance of payments shocks in a currency-board fashion. The growing level of international reserves can be rationalized, instead, as the monetary authority's response to terms of trade, supply and domestic currency demand shocks.
Ehrhart $f^*$-Coefficients of Polytopal Complexes are Non-negative Integers

The Ehrhart polynomial $L_P$ of an integral polytope $P$ counts the number of integer points in integral dilates of $P$. Ehrhart polynomials of polytopes are often described in terms of their Ehrhart $h^*$-vector (aka Ehrhart $\delta$-vector), which is the vector of coefficients of $L_P$ with respect to a certain binomial basis and which coincides with the $h$-vector of a regular unimodular triangulation of $P$ (if one exists). One important result by Stanley about $h^*$-vectors of polytopes is that their entries are always non-negative. However, recent combinatorial applications of Ehrhart theory give rise to polytopal complexes with $h^*$-vectors that have negative entries. In this article we introduce the Ehrhart $f^*$-vector of polytopes or, more generally, of polytopal complexes $K$. These are again coefficient vectors of $L_K$ with respect to a certain binomial basis of the space of polynomials and they have the property that the $f^*$-vector of a unimodular simplicial complex coincides with its $f$-vector. The main result of this article is a counting interpretation for the $f^*$-coefficients which implies that $f^*$-coefficients of integral polytopal complexes are always non-negative integers. This holds even if the polytopal complex does not have a unimodular triangulation and if its $h^*$-vector does have negative entries. Our main technical tool is a new partition of the set of lattice points in a simplicial cone into discrete cones. Further results include a complete characterization of Ehrhart polynomials of integral partial polytopal complexes and a non-negativity theorem for the $f^*$-vectors of rational polytopal complexes.
Free-Riding and Performance in Collaborative and Non-Collaborative Groups

Individuals bring effort to a group to achieve a common objective. Group membership introduces a free riding incentive, reducing effort, as well as a social responsibility incentive, increasing effort. This paper shows that the free riding effect is stronger. Individuals significantly reduce their effort as the difficulty of the task increases when they cannot collaborate in the group. Once collaboration is allowed, the negative effects of free riding are not observed. Collaborating groups outperform both groups without collaboration and individuals. They do as well as the best constituent member would have done on her own, thus aggregating existing knowledge.
A Program Logic for Verifying Secure Routing Protocols

The Internet, as it stands today, is highly vulnerable to attacks. However, little has been done to understand and verify the formal security guarantees of proposed secure inter-domain routing protocols, such as Secure BGP (S-BGP). In this paper, we develop a sound program logic for SANDLog—a declarative specification language for secure routing protocols—for verifying properties of these protocols. We prove invariant properties of SANDLog programs that run in an adversarial environment. As a step towards automated verification, we implement a verification condition generator (VCGen) to automatically extract proof obligations. VCGen is integrated into a compiler for SANDLog that can generate executable protocol implementations; and thus, both verification and empirical evaluation of secure routing protocols can be carried out in this unified framework. To validate our framework, we (1) encoded several proposed secure routing mechanisms in SANDLog, (2) verified variants of path authenticity properties by manually discharging the generated verification conditions in Coq, and (3) generated executable code based on SANDLog specification and ran the code in simulation.
Deforesting the Earth: From Prehistory to Global Crisis

Michael Williams. Chicago: University of Chicago Press, 2003. xxvi and 689 pp., figs., maps, tables, diagrams, photos, notes, bibliog., and index. $80.00 cloth (ISBN 0-226-89926-8). Deforestation, ...
Reconstitution of Golgi stacks from vesiculated Golgi membranes in permeabilized cells

Abstract Golgi membranes are organized into stacks of flattened cisternae in the cytoplasm of eukaryotic cells. These membranes are constantly budding and receiving small transport vesicles during protein trafficking. In mammalian cells, during mitosis, the Golgi cisternae break down extensively into small vesicles and tubules, which are partitioned into the cytoplasm of the newly formed daughter cells, where they fuse and assemble into stacks of cisternae. These findings raise intriguing questions; how Golgi membranes maintain their organization in stacks of cisternae amidst the tremendous membrane flux in non-dividing cells and how is the organization of the Golgi regulated in association with the cell cycle events? The scope of this article is to describe an assay that reconstitutes the process of Golgi stack formation from vesiculated Golgi membranes (VGMs) in semi-intact cells and to highlight some of the recent findings that increase our understanding of the mechanism of Golgi stack assembly.
Chemoselective TBS deprotection of primary alcohols by means of pyridinium tribromide (Py·Br3) in MeOH

Abstract A catalytic amount of pyridinium tribromide (Py·Br 3 ) in MeOH chemoselectively deprotects primary TBS ethers in the presence of a variety of other protecting and common functional groups in modest to excellent yields when performed at 0 °C.
The boundary N=2 supersymmetric sine-Gordon model

Abstract We construct an action for the N=2 supersymmetric sine-Gordon model on the half-line, which we argue is both supersymmetric and integrable. The boundary interaction depends on three continuous boundary parameters, as well as the bulk mass parameter.
Gauge/Gravity duality with a chiral N=(0,8) string defect

We study the defect AdS/CFT correspondence for a system of Nc D3-branes intersecting certain configurations of D7-branes and O7-planes in 1+1-dimensions. The intersection is chiral, preserving = (0, 8) supersymmetry. The geometry produced by the 7-branes does not decouple in the low energy limit on the D3-branes; consequently the field theory must be considered in the curved background of the 7-branes, and the supergravity background is the fully backreacted solution accounting for both sets of branes. Although we can not work in the probe-brane limit, we still find a consistent defect mode-operator map. In our previous study of the field theory we found chiral D3-brane zero-modes that localized to the intersection. Here we obtain a dual supergravity description of the localized R-symmetry anomaly that these zero-modes produce.
Dispersion of picosecond pulses propagating on microstrip interconnections on semiconductor integrated-circuit substrates

A weighted residual formulation for the transverse electric field is presented for the finite-element analysis of microstrip transmission lines on semiconductor substrates. The frequency dependence of the effective dielectric constant and the attenuation constant of the transmission lines are examined. The results from the full-wave analysis are used to determine when a quasi-TEM analysis is applicable.
Ion Beam Texturing of Heat-Transfer Surfaces

Nucleate boiling heat transfer is examined as a means of energy conservation. Nucleate boiling curves were obtained for ion beam textured copper surfaces, untreated cooper surfaces, copper surfaces which had been polished and surfaces which had been coated with a plasma deposited polymer. Results show that texturing aids heat transfer while polishing has the opposite effect. The polymer coatings did not change nucleate boiling behavior. Aging effects were observed for untreated and for polished surfaces, while no such effects were noticed for textured surfaces. These data suggest that aging may be dependent on surface microgeometry, which is important in nucleate boiling heat transfer.
A social cost-benefit criterion for evaluating Voluntary Counseling and Testing with an application to Tanzania.

Rationale: There are many interventions for HIV/AIDS that require that people know their status and hence require a HIV test. Testing that is driven by a desire to prevent the spread of the disease often has an indirect effect on others. These external effects need to be identified, quantified and included as part of the benefits and costs of testing. Pioneering analyses of HIV testing by Philipson and Posner have introduced the economic calculus of individual expected benefits and costs of activities into an understanding of the HIV epidemic. What is required for social evaluations is an extension of the analysis to ensure that external effects are included. Objectives: The objective of this paper is two-fold. First we seek to formulate cost–benefit criteria that incorporate fully the external effects in the evaluation of Voluntary Counseling and Testing (VCT). We achieve this by recasting the individual calculus of benefits and costs to a couple setting. We can then compare an individual's cost–benefit analysis of being tested with social criteria that look at outcomes from a couple's perspective for both separate and dual/joint testing. Second we aim to apply our social criteria to VCT programs as they currently operate in Tanzania and how these programs might operate in the future when they are scaled up to relate to the general population. Methodology: We develop social criteria for evaluating separate and dual VCT using a couple's perspective with and without altruism. Therefore, the welfare function is based on two individual expected utility functions viewed as a couple, either married or regular partners. The benefits are the averted lives lost whenever discordant couples are revealed. The costs of VCT are the benefits of unprotected sex that the couple foregoes and the costs of the testing and counseling. The cost–benefit criteria are applied to VCT programs in Tanzania. The four main ingredients estimated are: the foregone benefit of unprotected sex (measured by the compensated wage differentials charged by commercial sex workers); the probability of infection; the cost of an infection (measured by both the value of a statistical life and the human capital approaches) and the cost of a single test (which includes behavior-modifying counseling). Conclusions: We find separate testing in existing VCT programs to be only marginally worthwhile. However, in scaled-up programs the benefit–cost ratio is over three. Dual testing is always more beneficial than separate testing. However, this advantage is reduced in scaled-up programs. VCT should be greatly expanded throughout Tanzania as future returns would be even higher for both separate and joint counseling and HIV testing. Copyright © 2009 John Wiley & Sons, Ltd.
Dynamics of Pricing in the Video Game Console Market: Skimming or Penetration?

Abstract Nintendo lost its dominant position in the video game industry during the console war between its Nintendo 64 and Sony's PlayStation. However, Nintendo could have made several different strategic decisions to change the outcome. This article develops a structural model and investigates these alternative strategies through policy simulations. In particular, the author provides a framework to study firms' optimal pricing strategies under network effects, consumer heterogeneity, and oligopolistic competition. Consumer heterogeneity provides an incentive for a durable goods manufacturer to price skim, while network effects lead to an opposite motive for penetration pricing. The proposed framework incorporates these two competing motives under oligopolistic competition. The author estimates a demand system that allows for indirect network effects and consumer heterogeneity and then numerically solves for the Markov perfect equilibrium in firms' dynamic pricing game. Policy simulations indicate that Ni...
Weak–Strong Uniqueness for the Isentropic Compressible Navier–Stokes System

We prove weak–strong uniqueness results for the isentropic compressible Navier–Stokes system on the torus. In other words, we give conditions on a weak solution, such as the ones built up by Lions (Compressible Models, Oxford Science, Oxford, 1998), so that it is unique. It is of fundamental importance since uniqueness of these solutions is not known in general. We present two different methods, one using relative entropy, the other one using an improved Gronwall inequality due to the author; these two approaches yield complementary results. Known weak–strong uniqueness results are improved and classical uniqueness results for this equation follow naturally.
The unbounded-error communication complexity of symmetric functions

We prove an essentially tight lower bound on the unbounded-error communication complexity of every symmetric function, i.e., f(x,y)=D(|x∧y|), where D: {0,1,…,n}→{0,1} is a given predicate and x,y range over {0,1}n . Specifically, we show that the communication complexity of f is between Θ(k/log5 n) and Θ(k logn), where k is the number of value changes of D in {0,1,…, n}. Prior to this work, the problem was solved only for the parity predicate D (Forster 2001). Our proof is built around two new ideas. First, we show that a predicate D gives rise to a rapidly mixing random walk on ℤ2 n , which allows us to reduce the problem to communication lower bounds for “typical” predicates. Second, we use Paturi’s approximation lower bounds (1992), suitably generalized here to clusters of real nodes in [0,n] and interpreted in their dual form, to prove that a typical predicate behaves analogous to the parity predicate with respect to a smooth distribution on the inputs.
Callisto: Disk Temperature at 3.71-Centimeter Wavelength

We observed the radio emission of Callisto with a three-element interferometer at the time of the 1973 opposition of Jupiter. Special care was taken to remove the residual, unresolved contribution from Jupiter itself in the antenna side lobes. The resulting disk temperature at a wavelength of 3.71 centimeters, assuming a radius of 2500+/-75 kilometers for Callisto, was 101 degrees +/-25 degrees K. This temperature is much more consistent with emission from a simple dielectric sphere than the considerably higher temnperatures that have been reported for wavelengths of 3.5 and 8.2 millimeters.
Strongly regular graphs from unions of cyclotomic classes

We give two constructions of strongly regular Cayley graphs on finite fields F"q by using union of cyclotomic classes and index 2 Gauss sums. In particular, we obtain twelve infinite families of strongly regular graphs with new parameters.
The Role of Tip Clearance in High-Speed Fan Stall

A numerical experiment has been carried out to define the near-stall casing endwall flow field of a high-speed fan rotor. The experiment used a simulation code incorporating a simple clearance model, whose calibration is presented. The results of the simulation show that the interaction of the tip leakage vortex and the in-passage shock plays a major role in determining the fan flow range. More specifically, the computations imply that it is the area increase of this vortex as it passes through the in-passage shock that is the source of the blockage associated with stall. In addition, for fans of this type, it is the clearance over the forward portion of the fan blade that controls the flow processes leading to stall.
Alexandrov immersed minimal tori in $S^3$

We show that any minimal torus in $S^3$ which is Alexandrov immersed must be rotationally symmetric. An analogous result holds for surfaces of constant mean curvature.
Modeling and sizing for minimum energy operation in subthreshold circuits

This paper examines energy minimization for circuits operating in the subthreshold region. Subthreshold operation is emerging as an energy-saving approach to many energy-constrained applications where processor speed is less important. In this paper, we solve equations for total energy to provide an analytical solution for the optimum V/sub DD/ and V/sub T/ to minimize energy for a given frequency in subthreshold operation. We show the dependence of the optimum V/sub DD/ for a given technology on design characteristics and operating conditions. This paper also examines the effect of sizing on energy consumption for subthreshold circuits. We show that minimum sized devices are theoretically optimal for reducing energy. A fabricated 0.18-/spl mu/m test chip is used to compare normal sizing and sizing to minimize operational V/sub DD/ and to verify the energy models. Measurements show that existing standard cell libraries offer a good solution for minimizing energy in subthreshold circuits.
Evidence of Cosmic Evolution of the Stellar Initial Mass Function

Theoretical arguments and indirect observational evidence suggest that the stellar IMF may evolve with time, such that it is more weighted toward high-mass stars at higher redshift. Here we test this idea by comparing the rate of luminosity evolution of massive early-type galaxies in clusters at -->0.02 ≤ z≤ 0.83 to the rate of their color evolution. A combined fit to the rest-frame -->U − V color evolution and the previously measured evolution of the -->M/LB ratio gives -->x = − 0.3+ 0.4−0.7 for the logarithmic slope of the IMF in the region around 1 M☉, significantly flatter than the present-day value in the Milky Way disk of -->x = 1.3 ± 0.3. The best-fitting luminosity-weighted formation redshift of the stars in massive cluster galaxies is -->3.7+ 2.3−0.8, and a possible interpretation is that the characteristic mass -->mc had a value of ~2 M☉ at -->z ~ 4 (compared to -->mc ~ 0.1 M☉ today), in qualitative agreement with models in which the characteristic mass is a function of the Jeans mass in molecular clouds. Such a bottom-light IMF for massive cluster galaxies has significant implications for the interpretation of measurements of galaxy formation and evolution. Applying a simple form of IMF evolution to literature data, we find that the volume-averaged SFR at high redshift may have been overestimated (by a factor of 3-4 at -->z > 4), and the cosmic star formation history may have a fairly well defined peak at -->z ~ 1.5. The -->M/LV ratios of galaxies are less affected than their SFRs, and future data on the stellar mass density at -->z > 3 will provide further constraints on IMF evolution. The formal errors likely underestimate the uncertainties, and confirmation of these results requires a larger sample of clusters and the inclusion of redder rest-frame colors in the analysis.
Microscopic theory of atomic diffusion mechanisms in silicon

We report self-consistent Green's-function total-energy calculations which provide, for the first time, a firm theoretical framework for understanding the microscopic mechanisms of atomic diffusion in Si. We find that the self-interstitial has negative-$U$ properties, roughly the same formation energy at several sites, small migration barriers, and charge-state instabilities that allow athermal migration along several paths. We also find that both vacancies and interstitials mediate self-diffusion and reconcile contrasting low- and high-temperature data.
Preparation of Primary Thioamides From Nitriles Using Sodium Hydrogen Sulfide and Diethylamine Hydrochloride

Primary thioamides are prepared in moderate to excellent yields by treating nitriles with sodium hydrogen sulfide and diethylamine hydrochloride in an appropriate solvent with mild heating.
Illegal products and the question of consumer redress

Despite the enormous size of the illicit market in the United States, there is a paucity of research concerning the rights of consumers of illegal products. In this article it is argued that the illicit nature of a transaction should not deny consumers the right to safety and redress. Recognition of these rights is not only in line with the public policy goal, i.e., protecting public interests, but it can also serve as a deterrent factor for the sales of illegal products.
Development of a 2-Aza-Cope-[3+2] Dipolar Cycloaddition Strategy for the Synthesis of Quaternary Proline Scaffolds

A one-pot multicomponent procedure for the synthesis of highly functionalized pyrrolidine rings through a domino 2-aza-Cope-[3 + 2] dipolar cycloaddition sequence has been demonstrated. This protocol was found to be both high-yielding and stereoselective for the endo cycloadduct.
Measurement and calibration of large-area alpha-particle sources at NIST

Abstract Work has been performed at NIST to develop and calibrate large-area 238 Pu alpha-particle sources and related measuring equipment. A large-area-source X-ray counting system and a 2πα internal gas-proportional counting system were used for the primary calibration of these sources. Studies have been performed to relate these calibrations to the measurement of thin, large area 239 Pu sources, which are of primary interest but are generally unavailable in the necessary high specific activities required. Two systems have been characterized for the monitoring and measurement of large-area alpha sources: 1. (i) a source-detector mounting unit developed at NIST to calibrate monitoring systems by mounting a standard source of plutonium at an accurately calibrated distance from the user's alpha-monitoring detector; 2. (ii) a diffused-junction silicon semiconductor detector which is used as a transfer standard from low to high activity of large-area alpha-particle sources. A determination of the L X-ray emission probability for 239 Pu has been made.
Bridge Safety Assurance Measures Taken in New York State

A description of New York State's Bridge Safety Assurance (BSA) Program is given, and specific examples of interim countermeasures that can be taken to lessen the risk of failure due to hydraulic scour, overload, steel details, collision, concrete details, and earthquakes are provided. The BSA program was adopted to provide a systematic means of identifying situations that pose a threat to the structural integrity of bridges. A traditional bridge inspection program ascertains the condition of various bridge elements. This information is typically used to drive an agency's capital and maintenance bridge programs. New York's BSA program supplements this condition-based evaluation by taking a slightly different perspective. It assesses and rates the degree of risk that is associated with certain design details and circumstances. The program is used to evaluate a bridge by using current design practice as a reference, whereas the inspection procedures are used to rate each element of a bridge only according to its condition and ability to function as intended in the original design. Rating all bridges according to their ability to remain safe under current conditions by using today's design philosophy provides an ability to evaluate structures by using a common reference regardless of when they were built. Specific examples of retrofit work that has been undertaken as a result of the adoption of New York's BSA policy in 1992 are given.
Antikaon flow in heavy-ion collisions: Effects of absorption and mean-field potential.

We study antikaon flow in heavy-ion collisions at SIS energies based on the relativistic transport model (RVUU 1.0). The production of antikaons from both baryon-baryon and pion-baryon collisions are included. Taking into account only elastic and inelastic collisions of the antikaon with nucleons and neglecting its mean-field potential as in the cascade model, a strong antiflow or anticorrelation of antikaons with respect to nucleons is seen as a result of the strong absorption of antikaons by nucleons. However, the antiflow of antikaons disappears after including also their propagation in the attractive mean-field potential. The experimental measurement of antikaon flow in heavy-ion collision will be very useful in shedding light on the relative importance of antikaon absorption versus its mean-field potential. {copyright} {ital 1996 The American Physical Society.}
Synthesis of some 7‐substituted‐2,4,8(1H,3H,7H)pyrimido[5,4‐d]pyrimidinetriones

A synthesis of 2,4,8-pyrimido[5,4-d]pyrimidinetriones under mild conditions from ethyl 5-ethoxymethyleneamino-orotate allows the introduction of a variety of substituents regiospecifically into the 7-position. The 7-methyl and 7-benzyl derivatives were methylated with trimethyl phosphate to the 1,3,7-trialkyl derivatives.
Molecular Star Formation Rate Indicators in Galaxies

We derive a physical model for the observed relations between star formation rate (SFR) and molecular line (CO and HCN) emission in galaxies and show how these observed relations are reflective of the underlying star formation law. We do this by combining 3D non-LTE radiative transfer calculations with hydrodynamic simulations of isolated disk galaxies and galaxy mergers. We demonstrate that the observed SFR-molecular line relations are driven by the relationship between molecular line emission and gas density and anchored by the index of the underlying Schmidt law controlling the SFR in the galaxy. Lines with low critical densities (e.g., CO -->J = 1–0) are typically thermalized and trace the gas density faithfully. In these cases, the SFR will be related to line luminosity with an index similar to the Schmidt law index. Lines with high critical densities greater than the mean density of most of the emitting clouds in a galaxy (e.g., CO -->J = 3–2, HCN -->J = 1–0) will have only a small amount of thermalized gas and consequently a superlinear relationship between molecular line luminosity ( -->Lmol) and mean gas density ($o{n}$ -->). This results in an SFR-line luminosity index less than the Schmidt index for high critical density tracers. One observational consequence of this is a significant redistribution of light from the small pockets of dense, thermalized gas to diffuse gas along the line of sight, and prodigious emission from subthermally excited gas. At the highest star formation rates, the SFR- -->Lmol slope tends to the Schmidt index, regardless of the molecular transition. The fundamental relation is the Kennicutt-Schmidt law, rather than the relation between SFR and molecular line luminosity. Our model for SFR-molecular line relations quantitatively reproduces the slopes of the observed SFR-CO ( -->J = 1–0), CO ( -->J = 3–2), and HCN ( -->J = 1–0) relations when a Schmidt law with index of ~1.5 describes the SFR. We use these results to make imminently testable predictions for the SFR-molecular line relations of unobserved transitions.
Thiolysis of oxazolines: A new, selective method for the direct conversion of peptide oxazolines into thiazolines

Abstract A direct oxazoline→thiazoline conversion can be realized by thiolysis of oxazolines with H2S in methanol/triethylamine, followed by cyclodehydration with Burgess reagent. This protocol is high-yielding, chemoselective, and essentially free of racemization for C(5)-unsubstituted and trans-4,5-disubstituted peptide oxazolines. Thioamide intermediates are obtained regioselectively, thus the thiolysis of oxazolines offers an alternative to the thiation of peptides with Lawesson's reagent.
Measuring oscillatory velocity fields due to swimming algae

Single cells exhibit a diverse array of swimming strategies at low Reynolds number to search for nutrients, light, and other organisms. The fluid flows generated by their locomotion are important to understanding biomixing and interactions between cells in suspension..."
Weak Hironaka theorem

The purpose of this note is to give a simple proof of the following theorem: Let $X$ be a normal projective variety over an algebraically closed field $k$, $\op{char} k = 0$ and let $D \subset X$ be a proper closed subvariety of $X$. Then there exist a smooth projective variety $M$, a strict normal crossings divisor $R \subset M$ and a birational morphism $f : M \to X$ with $f^{-1} D = R$. The method of proof is inspired by A.J. de Jong alteration ideas. We also use a multidimensional version of G.Belyi argument which allows us to simplify the shape of a ramification divisor. By induction on the dimension of $X$ the problem is reduced to resolving toroidal singularities. This process however is too crude and does not permit any control over the structure of the birational map $f$. A different proof of the same theorem was found independently by D. Abramovich and A.J. de Jong. The approach is similar in both proofs but they seem to be rather different in details.
The effect of Fed monetary policy regimes on the US interest rate swap spreads

Abstract This paper analyzes the asymmetric impacts of various economic shocks on swap spreads under distinct Fed monetary policy regimes. The results indicate that (a) during periods of aggressive interest rate reductions, slope of the Treasury term structure accounts for a sizeable share of the swap spread variance although default shock is also a major player. (b) On the other hand, liquidity premium is the only contributor to the 2-year swap spread variance in monetary tightening cycles. (c) The impact of default risk varies across both monetary cycles and swap maturities. (d) The effect of interest rate volatility is generally more evident in loosening monetary regimes.
Higher alcohol and oxygenate synthesis over Cs/Cu/ZnO/M2O3 (M Al, Cr) catalysts

Surface doping of Cu/ZnO/M{sub 2}O{sub 3} (M = Al, Cr) catalysts prepared from hydrotalcite precursors with cesium (Cs/Cu/ZnO/M{sub 2}O{sub 3}) significantly enhanced to the alcohol synthesis rate under higher alcohol synthesis conditions. With respect to the unsupported Cs/Cu/ZnO catalyst, the product selectivity of the Cs/Cu/ZnO/Al{sub 2}O{sub 3} catalyst was shifted toward methanol, while the Cs/Cu/ZnO/Cr{sub 2}O{sub 3} catalyst maintained a high selectivity toward C{sub 2}{sup +} alcohols. The presence of cesium in the Cu/ZnO/M{sub 2}O{sub 3} catalysts inhibited the synthesis of dimethyl ether. Comparison of the product distributions obtained over the Cs/Cu/ZnO/M{sub 2}O{sub 3} catalysts with those observed over the Cs/Cu/ZnO catalysts indicates that the function of the Cs/Cu/ZnO/Cr{sub 2}O{sub 3} catalyst is similar to that of the Cs/Cu/ZnO in that higher alcohols are synthesized by a stepwise carbon chain growth via a unique aldol coupling with oxygen retention reversal mechanism. The Al{sub 2}O{sub 3}-based catalysts undergo complex structural changes that probably cause occlusion of the Cs dopant, thus resulting in low selectivity to higher alcohols while retaining high activity toward methanol. 23 refs.
Integrating energy storage into the smart grid: A prospect theoretic approach

In this paper, the interactions and energy exchange decisions of a number of geographically distributed storage units are studied under decision-making involving end-users. In particular, a noncooperative game is formulated between customer-owned storage units where each storage unit's owner can decide on whether to charge or discharge energy with a given probability so as to maximize a utility that reflects the tradeoff between the monetary transactions from charging/discharging and the penalty from power regulation. Unlike existing game-theoretic works which assume that players make their decisions rationally and objectively, we use the new framework of prospect theory (PT) to explicitly incorporate the users' subjective perceptions of their expected utilities. For the two-player game, we show the existence of a proper mixed Nash equilibrium for both the standard game-theoretic case and the case with PT considerations. Simulation results show that incorporating user behavior via PT reveals several important insights into load management as well as economics of energy storage usage. For instance, the results show that deviations from conventional game theory, as predicted by PT, can lead to undesirable grid loads and revenues thus requiring the power company to revisit its pricing schemes and the customers to reassess their energy storage usage choices.