cssi/SciSciGPT-SciSciNet huggingface dataset:
Cooperative Heart Disease Trials

This review of multicenter trials in heart disease sponsored by the United States National Heart, Lung, and Blood Institute illustrates some design and biostatistical advances that selected trials have developed or used effectively to answer important public health questions. Many of the design, organizational characteristics and methods for monitoring modern clinical trials were implemented as a result of the Greenberg Report completed in 1967 and were first used in the Coronary Drug Project during the 1960s. While more recent studies employed more efficient organizations, newer designs, and newer monitoring guidelines, the genesis of multicenter clinical trial practice in heart disease was outlined in the 1960s and that early structure has endured the test of time. Keywords: NIH ; HHLBI ; clinical trial; data monitoring; CDP ; HDFP ; MRFIT ; LRC-CPPT; BHAT ; CASS ; CAST ; WHI
Clustering without (thinking about) triangulation

The undirected technique for evaluating belief networks [Jensen et al., 199Oa, Lauritzen and Spiegelhalter, 1988] requires clustering the nodes in the network into a junction tree. In the traditional view, the junction tree is constructed from the cliques of the moralized and triangulated belief network: triangulation is taken to be the primitive concept, the goal towards which any clustering algorithm (e.g. node elimination) is directed. In this paper, we present, an alternative conception of clustering, in which clusters and the junction tree property play the role of primitives: given a graph (not a tree) of clusters which obey (a modified version of) the junction tree property, we transform this graph until we have obtained a tree. There are several advantages to this approach: it is much clearer and easier to understand, which is important for humans who are constructing belief networks; it admits a wider range of heuristics which may enable more efficient or superior clustering algorithms; and it serves as the natural basis for an incremental clustering scheme, which we describe.
The Politics of Economic Policy Reform in Developing Countries

Various social groups may oppose economic reforms such as currency devaluation, privatization of state firms, and the elimination of consumer (food) subsidies because of doubts about the benefits of these reforms or because they believe that these reforms will harm their economic interests. Whether such opposition can stall reform depends on the aggregate political weight of the affected social groups. Because of politics, some economic policy reforms are adopted and pursued in the developing world and others are delayed and resisted. Economic reform is inherently a political act: It changes the distribution of benefits in society, benefiting some social groups and hurting others. Social groups may oppose reform because of doubts about its benefits or because they know it will harm their economic interests. Adams shows how three types of reform - currency devaluation, the privatization of state enterprises, and the elimination of consumer (food) subsidies - affect the utility of nine different social groups (including international financial institutions). When governments try to privatize state-owned enterprises, for example, more social groups with greater political weight are likely to be disadvantaged than helped. Urban workers, urban bureaucrats, urban students, and the urban poor are likely to lose out and will strongly oppose privatization. But the ruling elite and urban politicians are also likely to at least partly resist privatization, fearing that such reform will reduce their economic rents. More social groups and power points thus oppose privatization than favor it, so this policy reform is likely to be delayed or not implemented at all. However, social groups do not possess an absolute veto over economic reform, and policy reform can (and often does) occur despite the opposition of certain social groups. It depends on the aggregate political weight of the groups opposing reform. For example, as Adams shows, five social groups either wholly or partly oppose eliminating consumer (food) subsidies, but the combined weight of those groups is only roughly equal to the political weight of the four social groups - international financial institutions, the ruling elite, urban politicians, and urban capitalists - that favor this reform. Politically, consumer subsidies can be eliminated or reduced if the right kind of concern is shown for opposing social groups. This paper - a product of the Poverty Division, Poverty Reduction and Economic Management Network - is part of a larger effort in the network to understand the political economy issues affecting economic reform and poverty interventions. The author may be contacted at radams@worldbank.org.
Genetic control by metabolite-binding riboswitches

Modern organisms must coordinate the expression of many hundreds of genes in response to metabolic demands and environmental changes. Each gene product must be regulated temporally, quantitatively, and often spatially. Additionally, genetic control processes must be dynamic, rapid, and selectively responsive to the specific conditions undergoing change. Therefore, organisms require sentries of genetic regulatory factors that continuously quantify a multitude of signals. Upon measurement of a particular signal, which may be one of many possible biochemical or physical cues, these regulatory factors must modulate expression of a specific subset of the organism's genes. It has generally been assumed that proteins are the obligate sensors of these signals because protein is a proven medium for forming highly responsive sensors. However, recent findings demonstrate that mRNAs also are capable of acting as direct sensors of chemical and physical conditions for the purpose of genetic control. Classes of mRNA domains, collectively referred to as 'riboswitches', serve as RNA genetic control elements that sense the concentrations of specific metabolites by directly binding the target compound. Known riboswitches are responsible for sensing metabolites that are critical for fundamental biochemical processes including coenzyme B12, thiamine pyrophosphate (TPP), flavin mononucleotide (FMN), 5] S-adenosylmethionine (SAM), 7, 9] lysine, guanine, and adenine. 11] Upon interaction with the appropriate smallmolecule ligand, riboswitch mRNAs undergo a structural reorganization that results in the modulation of genes that they encode. To date, all riboswitches that have been examined in detail cause genetic repression upon binding their target ligand, although riboswitches that activate gene expression upon ligand binding are certainly possible. In each instance, riboswitch domains have been subjected to a battery of biochemical and genetic analyses in order to convincingly demonstrate that direct interaction of small organic metabolites with mRNA receptors leads to a corresponding alteration in genetic expression. This review provides a brief summary of these efforts and of some of the general characteristics that are exhibited by riboswitches. Although these findings represent the initial steps in elucidating the principles that underlie RNA-based detection of small molecules, the prospects for riboswitches as genetic tools and as possible targets for development of antimicrobials are already beginning to emerge. 2. General Organization of Riboswitch RNAs
On Effective Procedures for Speeding Up Algorithms

This paper is concerned with the nature of speedups. Let f be any recursive func- tion. We show that there is no effective procedure for going from an algorithm forf to another algorithm for f that is significantly faster on all but a finite number of inputs. On the other hand, for a large class of functions f, one can go effectively from any algorithm for f to one that is faster on at least infinitely many integers. Finally, if one has an algorithm for a given function f, and if there is an algorithm which is faster on all but a finite number of inputs, then even though one cannot get this faster algorithm effectively, one can still obtain a pseudo- speedup: This is a very fast algorithm which computes a variant of the function, one which differs from the original function on a finite number of inputs.
Crystal–Melt Separation and the Development of Isotopic Heterogeneities in Hybrid Magmas

If a magma is a hybrid of two (or more) isotopically distinct endmembers, at least one of which is partially crystalline, separation of melt and crystals after hybridization will lead to the development of isotopic heterogeneities in the magma as long as some of the preexisting crystalline material (antecrysts) retains any of its original isotopic composition.This holds true whether the hybridization event is magma mixing as traditionally construed, bulk assimilation, or melt assimilation. Once a magma-scale isotopic heterogeneity is formed by crystal^melt separation, it is essentially permanent, persisting regardless of subsequent crystallization, mixing, or equilibration events. The magnitude of the isotopic variability resulting from crystal^melt separation can be as large as that resulting from differential contamination, multiple isotopically distinct sources, or in situ isotopic evolution. In one model, a redistribution of onethird of the antecryst cargo yielded a crystal-enriched sample with 87 Sr/ 86 Sr of 0� 7058, whereas the complementary crystal-poor sample has 87 Sr/ 86 Sr of 0� 7068. In other models, crystal-rich samples are enriched in radiogenic Sr. Isotopic heterogeneities can be either continuous (controlled by the modal distribution of crystals and melt) or discontinuous (when there is complete separation of crystals and liquid). The first case may be exemplified by some isotopically zoned large-volume rhyolites, formed by the eruptive inversion of a modally zoned magma chamber. In the latter case, the isotopic composition of any (for example) interstitial liquid will be distinct from the isotopic composition of the bulk crystal fraction.The separation of such an interstitial liquid may explain the presence of isotopically distinct late-stage aplites in plutons. Crystal^melt separation provides an additional option for the interpretation of isotopically zoned or heterogeneous magmas.This option is particularly attractive for systems whose chemical variation is otherwise explicable by fractionation-dominated processes. Non-isotopic chemical heterogeneities can also develop in this fashion.
Measurement of bone mineral in vivo: an improved method

The mineral content of bone can be determined by measuring the absorption by bone of a monochromatic, low-energy photon beam which originates in a radioactive source (iodine-125 at 27.3 kev or americium-241 at 59.6 kev). The intensity of the beam transmitted by the bone is measured by counting with a scintillation detector. Since the photon source and detector are well collimated, errors resulting from scattered radiation are reduced. From measurements of the intensity of the transmitted beam, made at intervals across the bone, the total mineral content of the bone can be determined. The results are accurate and reproducible to within about 3 percent.
Post‐Newtonian limitations on measurement of the PPN parameters caused by motion of gravitating bodies

We derive an explicit Lorentz-invariant solution of the Einstein and null geodesic equations for data processing of the time delay and ranging experiments in the gravitational field of moving gravitating bodies of the Solar system – the Sun and major planets. We discuss the generalrelativistic interpretation of these experiments and the limitations imposed by motion of the massive bodies on measurement of the parameters γ PPN, βPPN and δPPN of the parametrized post-Newtonian (PPN) formalism.
A Shifting Mandate: International Ownership, Global Fragmentation, and a Case for Deeper Integration under the WTO

This paper reviews several key implications of international investment and global supply chain fragmentation for the multilateral trading system. Based on existing economic research, I identify a two-fold challenge for policy makers: first, to leverage the trade-liberalizing potential of global fragmentation at the multilateral level; and, second, to counter the potential for opportunistic manipulation of behind-the-border policy instruments.
Triazene formation via reaction of imidazol-2-ylidenes with azides

Treatment of N-heterocyclic carbenes (as their free carbenes or generated in situ) with alkyl, aryl, acyl or tosyl azides afforded the respective substituted triazenes in excellent yields.
Compressive Earth observatory: An insight from AIRS/AMSU retrievals

We demonstrate that the global fields of temperature, humidity, and geopotential heights admit a nearly sparse representation in the wavelet domain, offering a viable path forward to explore new paradigms of sparsity-promoting data assimilation and compressive recovery of land surface-atmospheric states from space. We illustrate this idea using retrieval products of the Atmospheric Infrared Sounder (AIRS) and Advanced Microwave Sounding Unit (AMSU) on board the Aqua satellite. The results reveal that the sparsity of the fields of temperature is relatively pressure independent, while atmospheric humidity and geopotential heights are typically sparser at lower and higher pressure levels, respectively. We provide evidence that these land-atmospheric states can be accurately estimated using a small set of measurements by taking advantage of their sparsity prior.
QUASI-ACTIONS ON TREES AND PROPERTY (QFA)

We prove some general results about quasi-actions on trees and define Property (QFA), which is analogous to Serre's Property (FA), but in the coarse setting. This property is shown to hold for a class of groups, including SL(n, Z) for n ≥ 3. We also give a way of thinking about Property (QFA) by breaking it down into statements about particular classes of trees.
Power-Bandwidth Tradeoff in Dense Multi-Antenna Relay Networks

We consider a dense fading multi-user network with multiple active multi-antenna source-destination pair terminals communicating simultaneously through a large common set of K multi-antenna relay terminals in the full spatial multiplexing mode. We use Shannon-theoretic tools to analyze the tradeoff between energy efficiency and spectral efficiency (known as the power-bandwidth tradeoff) in meaningful asymptotic regimes of signal-to-noise ratio (SNR) and network size. We design linear distributed multi-antenna relay beamforming (LDMRB) schemes that exploit the spatial signature of multi-user interference and characterize their power-bandwidth tradeoff under a system-wide power constraint on source and relay transmissions. The impact of multiple users, multiple relays and multiple antennas on the key performance measures of the high and low SNR regimes is investigated in order to shed new light on the possible reduction in power and bandwidth requirements through the usage of such practical relay cooperation techniques. Our results indicate that point-to-point coded multi-user networks supported by distributed relay beamforming techniques yield enhanced energy efficiency and spectral efficiency, and with appropriate signaling and sufficient antenna degrees of freedom, can achieve asymptotically optimal power-bandwidth tradeoff with the best possible (i.e., as in the cutset bound) energy scaling of K-1 and the best possible spectral efficiency slope at any SNR for large number of relay terminals. Furthermore, our results help to identify the role of interference cancellation capability at the relay terminals on realizing the optimal power- bandwidth tradeoff; and show how relaying schemes that do not attempt to mitigate multi-user interference, despite their optimal capacity scaling performance, could yield a poor power- bandwidth tradeoff.
Robust Parsing Based on Discourse Information: Completing partial parses of ill-formed sentences on the basis of discourse information

In a consistent text, many words and phrases are repeatedly used in more than one sentence. When an identical phrase (a set of consecutive words) is repeated in different sentences, the constituent words of those sentences tend to be associated in identical modification patterns with identical parts of speech and identical modifiee-modifier relationships. Thus, when a syntactic parser cannot parse a sentence as a unified structure, parts of speech and modifiee-modifier relationships among morphologically identical words in complete parses of other sentences within the same text provide useful information for obtaining partial parses of the sentence.In this paper, we describe a method for completing partial parses by maintaining consistency among morphologically identical words within the same text as regards their part of speech and their modifiee-modifier relationship. The experimental results obtained by using this method with technical documents offer good prospects for improving the accuracy of sentence analysis in a broad-coverage natural language processing system such as a machine translation system.
Fast Firing and Conventional Sintering of Lead Zirconate Titanate Ceramic

Conventional sintering and fast firing were examined as sintering techniques for PZT-5 pressed compacts. Density maxima of 7.42 ± 0.05 and 7.66 ± 0.01 g/cm3 were obtained at 1350°C for conventionally sintered ceramics and at 1300°C for fast-fired ceramics, respectively. Analysis of the ceramic obtained from these two sintering routes showed fast-fired material to possess a three-point fracture strength 33% greater and an average grain size almost 50% less than the conventionally sintered counterpart.
Beyond Sentiment: The Manifold of Human Emotions

Sentiment analysis predicts the presence of positive or negative emotions in a text document. In this paper we consider higher dimensional extensions of the sentiment concept, which represent a richer set of human emotions. Our approach goes beyond previous work in that our model contains a continuous manifold rather than a nite set of human emotions. We investigate the resulting model, compare it to psychological observations, and explore its predictive capabilities. Besides obtaining signicant improvements over a baseline without manifold, we are also able to visualize dierent notions of positive sentiment in dierent domains.
A pre- + post- + feedforward compensator design for zero placement

We demonstrate the design of a pre- + post- + feedforward compensator that places the transmission zeros of a stabilizable and detectable multi-input multi-output linear-time-invariant plant at arbitrary locations.
Meta-Regression Estimates for CGE Models: A Case Study for Input Substitution Elasticities in Production Agriculture

The selection of appropriate parameters for computable general equilibrium (CGE) models critically affects the results of applied economic modeling exercises. Valid and reliable parameter selection models are needed, and typically comprise direct estimation, expert opinion, or copycatting of results from seminal studies. The purpose of this study is to use meta-analysis to summarize and more accurately estimate elasticities of input substitution, specifically between labor and other inputs in agricultural production. We construct a comprehensive database of elasticity estimates through an extensive literature review, and perform a meta-regression analysis to identify structural sources of variation in elasticity estimates sampled from primary studies. The use of meta-analysis contributes to improved baseline analysis in CGE simulations because it allows for the computation of input parameters tailored to a specific CGE model setup. We correct for variations in research design, which are typically constant within studies, and account for bias associated with undue selection effects associated with editorial publication decision processes. Improved accuracy and knowledge of the distribution of imputed input parameters derived from a meta-analysis contributes to improved performance of CGE sensitivity analyses.
Loud and Clear: Human-Verifiable Authentication Based on Audio

Secure pairing of electronic devices that lack any previous association is a challenging problem which has been considered in many contexts and in various flavors. In this paper, we investigate the use of audio for human-assisted authentication of previously un-associated devices. We develop and evaluate a system we call Loud-and-Clear (L&C) which places very little demand on the human user. L&C involves the use of a text-to-speech (TTS) engine for vocalizing a robust-sounding and syntactically-correct (English-like) sentence derived from the hash of a devices public key. By coupling vocalization on one device with the display of the same information on another device, we demonstrate that L&C is suitable for secure device pairing (e.g., key exchange) and similar tasks. We also describe several common use cases, provide some performance data for our prototype implementation and discuss the security properties of L&C.
DISCOVERY OF AN ULTRACOOL WHITE DWARF COMPANION

The discovery of a low-luminosity common proper-motion companion to the white dwarf GD 392 at a wide separation of 46'' is reported. BVRI photometry suggests a low temperature (Teff ~ 4000 K), while JHK data strongly indicate suppressed flux at all near-infrared wavelengths. Thus, GD 392B is one of the few white dwarfs to show significant collision-induced absorption due to the presence of photospheric H2 and the first ultracool white dwarf detected as a companion to another star. Models fail to explain GD 392B as a normal-mass white dwarf. If correct, the cool companion may be explained as a low-mass white dwarf or unresolved double degenerate. The similarities of GD 392B to known ultracool degenerates are discussed, including some possible implications for the faint end of the white dwarf luminosity function.
On the capacities of bipartite Hamiltonians and unitary gates

We consider interactions as bidirectional channels. We investigate the capacities for interaction Hamiltonians and nonlocal unitary gates to generate entanglement and transmit classical information. We give analytic expressions for the entanglement generating capacity and entanglement-assisted one-way classical communication capacity of interactions, and show that these quantities are additive, so that the asymptotic capacities equal the corresponding 1-shot capacities. We give general bounds on other capacities, discuss some examples, and conclude with some open questions.
Lifetime cumulative risk factors predict cardiovascular disease mortality in a 50-year follow-up study in Finland

BACKGROUND Systolic blood pressure, total cholesterol and smoking are known predictors of cardiovascular disease (CVD) mortality. Less is known about the effect of lifetime accumulation and changes of risk factors over time as predictors of CVD mortality, especially in very long follow-up studies. METHODS Data from the Finnish cohorts of the Seven Countries Study were used. The baseline examination was in 1959 and seven re-examinations were carried out at approximately 5-year intervals. Cohorts were followed up for mortality until the end of 2011. Time-dependent Cox models with regular time-updated risk factors, time-dependent averages of risk factors and latest changes in risk factors, using smoothing splines to discover nonlinear effects, were used to analyse the predictive effect of risk factors for CVD mortality. RESULTS A model using cumulative risk factors, modelled as the individual-level averages of several risk factor measurements over time, predicted CVD mortality better than a model using the most recent measurement information. This difference seemed to be most prominent for systolic blood pressure. U-shaped effects of the original predictors can be explained by partitioning a risk factor effect between the recent level and the change trajectory. The change in body mass index predicted the risk although body mass index itself did not. CONCLUSIONS The lifetime accumulation of risk factors and the observed changes in risk factor levels over time are strong predictors of CVD mortality. It is important to investigate different ways of using the longitudinal risk factor measurements to take full advantage of them.
The complexity of optimal mechanism design

Myerson's seminal work provides a computationally efficient revenue-optimal auction for selling one item to multiple bidders [18]. Generalizing this work to selling multiple items at once has been a central question in economics and algorithmic game theory, but its complexity has remained poorly understood. We answer this question by showing that a revenue-optimal auction in multi-item settings cannot be found and implemented computationally efficiently, unless ZPP ⊇ P#P. This is true even for a single additive bidder whose values for the items are independently distributed on two rational numbers with rational probabilities. Our result is very general: we show that it is hard to compute any encoding of an optimal auction of any format (direct or indirect, truthful or non-truthful) that can be implemented in expected polynomial time. In particular, under well-believed complexity-theoretic assumptions, revenue-optimization in very simple multi-item settings can only be tractably approximated.We note that our hardness result applies to randomized mechanisms in a very simple setting, and is not an artifact of introducing combinatorial structure to the problem by allowing correlation among item values, introducing combinatorial valuations, or requiring the mechanism to be deterministic (whose structure is readily combinatorial). Our proof is enabled by a flow-interpretation of the solutions of an exponential-size linear program for revenue maximization with an additional supermodularity constraint.
Supercomputer applications in computational fluid dynamics

The field of computational fluid dynamics (CFD) using large-scale supercomputer applications is discussed. Formulational and computational requirements for the various governing equations, including the Euler and Navier-Stokes approaches, are examined for typical problems including the viscous flow field solution about a complete aerospace vehicle. Recent computed results and experimental comparisons are given to highlight the presentation. The future of CFD associated with three-dimensional applications is found to be rapidly expanding across a broad front, including internal and external flows and flows across the entire speed regime. >
Reliability-Based Optimal Design of a Bistable Compliant Mechanism

Compliant mechanisms obtain at least some of their motion from the deflection of their flexible members. Advantages of such mechanisms include the reduction of manufacturing and assembly cost and time. Bistable mechanisms are particularly useful in applications where two stable equilibrium positions are required, such as switches, gates, and closures. Fatigue is a major concern in many compliant mechanisms due to the cyclic stresses induced on the flexible members. In this paper, a method for the probabilistic design of a bistable compliant slider-crank mechanism is proposed. Link lengths, material properties, and cross-section dimensions are taken as random variables. Probabilistic constraints on the maximum and minimum required input torque, location of stable equilibrium position, and overall size are included. The objective function is the maximization of the mechanism reliability in fatigue. Several design studies are performed to gain further insight into the nature of the problem.
Benzene forms hydrogen bonds with water.

Fully rotationally resolved spectra of three isotopic species of 1:1 clusters of benzene with water (H_2O, D_2O, and HDO) were fit to yield moments of inertia that demonstrate unambiguously that water is positioned above the benzene plane in nearly free internal rotation with both hydrogen atoms pointing toward the π cloud. Ab initio calculations (MP2 level of electron correlation and 6-31 G** basis set with basis set superposition error corrections) predict a binding energy D_e ≳ 1.78 kilocalories per mole. In both the experimental and theoretical structures, water is situated nearly 1 angstrom within the van der Waals contacts of the monomers, a clear manifestation of hydrogen bond formation in this simple model of aqueous-π electron interactions.
Assessing Monetary Policy Effects Using Daily Fed Funds Futures Contracts

This paper develops a generalization of the formulas proposed by Kuttner (2001) and others for purposes of measuring the effects of a change in the federal funds target on Treasury yields of different maturities. The generalization avoids the need to condition on the date of the target change and allows for deviations of the effective fed funds rate from the target as well as gradual learning by market participants about the target. The paper shows that parameters estimated solely on the basis of the behavior of the fed funds and fed funds futures can account for the broad calendar regularities in the relation between fed funds futures and Treasury yields of different maturities. Although the methods are new, the conclusion is quite similar to that reported by earlier researchers— changes in the fed funds target seem to be associated with quite large changes in Treasury yields, even for maturities of up to 10 years. (JEL: E52, E43)
A Facile Synthetic Method to Prepare Fluorescently Labeled ROMP Polymers

To probe the activities of sperm ADAM protein (fertilinβ), we devised a general synthetic strategy to generate fluorescently labeled fertilinβ oligopeptide polymers. Immunofluorescence studies with these polymers demonstrated that fertilinβ polymers bind specifically to a protein receptor on the mouse egg plasma membrane.
Economic Evaluation of Rice-Prawn Gher Farming System on Soil Fertility for Modern Variety (MV) Paddy Production in Bangladesh

This present study attempts to examine the economic evaluation of rice-prawn gher farming system on land fertility for modern variety (MV) paddy production in Bangladesh. Laboratory based experimental data and field survey data were used in the present study. To test the change of land fertility, soils were collected before paddy production (after prawn production) and after paddy production (before prawn production) and tested in the Soil Resource Development Institute (SRDI) laboratory in Khulna, Bangladesh. The findings of the study indicate that the farmer applied comparatively less chemical fertilizers in MV paddy production under the rice-prawn gher farming system compared to MV paddy production. The input cost of chemical fertilizers for MV paddy farming was about six times higher than MV paddy production under the rice-prawn gher farming system. However, per acre MV paddy production of MV paddy farming was almost same to MV paddy production under the rice-prawn gher farming system. The rice-prawn gher farming is a cost-saving technology for MV paddy production.
Nonlinear controllers for positive real systems with arbitrary input nonlinearities

Input nonlinearities such as saturation can severely degrade closed-loop performance due to integrator windup and other effects. For positive real plants with positive real controllers, we propose a nonlinear controller modification that effectively counteracts the effects of arbitrary input nonlinearities. For this class of problems, we prove global asymptotic stability of the closed-loop system and demonstrate closed-loop performance by means of system simulation. >
A TWO-STAGE INFORMATION-THEORETIC APPROACH TO MODELING LANDSCAPE- LEVEL ATTRIBUTES AND MAXIMUM RECRUITMENT OF CHINOOK SALMON IN THE COLUMBIA RIVER BASIN

Many anadromous salmonid stocks in the Pacific Northwest are at their lowest recorded levels, which has raised questions regarding their long-term persistence under current conditions. There are a number of factors, such as freshwater spawning and rearing habitat, that could potentially influence their numbers. Therefore, we used the latest advances in information-theoretic methods in a two-stage modeling process to investigate relationships between landscape-level habitat attributes and maximum recruitment of 25 index stocks of chinook salmon (Onocorhynchus tshawytscha) in the Columbia River basin. Our first-stage model selection results indicated that the Ricker-type, stock recruitment model with a constant Ricker a, i.e., recruits-per-spawner at low numbers of fish) across stocks was the only plausible one given these data, which contrasted with previous unpublished findings. Our second-stage results revealed that maximum recruitment of chinook salmon had a strongly negative relationship with percentage of surrounding subwatersheds categorized as predominantly containing U.S. Forest Service and private moderate-high impact managed forest. That is, our model predicted that average maximum recruitment of chinook salmon would decrease by at least 247 fish for every increase of 33% in surrounding subwatersheds categorized as predominantly containing U.S. Forest Service and privately managed forest. Conversely, mean annual air temperature had a positive relationship with salmon maximum recruitment, with an average increase of at least 179 fish for every increase in 2oC mean annual air temperature.
An Experimental Investigation into the Effect of Surfactants on Air-Water Two-Phase Flow in Minichannels

The complex interfacial phenomena involved in two-phase gas-liquid flow have defied mathematical simplification and modeling. However, these systems are used in heat exchangers, condensers, chemical processing plants, nuclear reactor systems, and fuel cells. The present work considers a 1 mm-square minichannel and adiabatic flows corresponding to practical PEM fuel cell conditions. Pressure drop data is collected over mass fluxes of 4.0–12.0 kg/m2s for air and 0.5–21.6 kg/m2s for water, corresponding to superficial gas and liquid velocities of 3.19–10.06 m/s and 0.0005–0.022 m/s, respectively. The experiments are repeated with water-surfactant mixtures of different concentrations in order to quantify the surface tension effects, as it is recognized that surface tension is an important parameter for two-phase flow in minichannels. The accuracy of various two-phase pressure drop models is evaluated, and a new model for laminar-laminar two-phase flow pressure drop is developed.
Simulation of blunt-fin-induced shock wave and turbulent boundary-layer interaction

The Reynolds-averaged Navier-Stokes equations are solved numerically for supersonic flow over a blunt fin mounted on a flat plate. The fin shock causes the boundary layer to separate. which results in a complicated, three-dimensional shock-wave and boundary-layer interaction. The computed results are in good agreement with the mean static pressure measured on the fin and the flat plate. The main features, such as peak pressure on the fin leading edge and a double peak on the plate. are predicted well. The role of the horseshoe vortex is discussed. This vortex leads to the development of high-speed flow and, hence, low-pressure regions on the fin and the plate. Different thicknesses of the incoming boundary layer have been studied. Varying the thicknesses by an order of magnitude shows that the size of the horseshoe vortex and, therefore, the spatial extent of the interaction are dominated by inviscid flow and only weakly dependent on the Reynolds number. Colored graphics are used to show details of the interaction flow field.
Asymmetric Synthesis of 2H-Azirine 3-Carboxylates

Dehydrochlorination of methyl 2-chloroaziridine 2-carboxylates generates the first examples of enantiopure 2-substituted 2H-azirine 3-carboxylates which undergo the aza Diels−Alder reaction with dienes to give bicyclic and tricyclic aziridines in good yields.
Distinguishing between knowledge transfer and technology transfer activities: the role of key organizational factors

Knowledge transfer and technology transfer are often used interchangeably and while both knowledge transfer and technology transfer are highly interactive activities, they serve different purposes. Knowledge transfer implies a broader, more inclusive construct that is directed more toward understanding the "whys" for change. In contrast, technology transfer is a narrower and more targeted construct that usually embodies certain tools for changing the environment. Grounding our work in the 7-S framework, we examine the role of key organizational factors in facilitating knowledge transfer and technology transfer activities. Survey data for this study were collected from 189 industrial firms representing 21 different industrial sectors. Results show that there are differences in the types of firm structures, cultures and university policies for intellectual property rights (IPR), patent ownership, and licensing that facilitated knowledge transfer activities compared to those that facilitated technology transfer activities. Specifically, firms with more mechanistic structures and more stable direction-oriented cultures were associated with higher levels of knowledge transfer. Conversely, firms with more organic structures, more flexible change-oriented cultures, and more customized university policies for IPR, patent ownership, and licensing were associated with higher levels of technology transfer. The firm's trust in its university research center partner was equally important for both activities. We conclude by discussing the implications of our findings for future research and management practice.
Janossy Densities II. Pfaffian Ensembles

We extend the main result of the companion paper J. Stat. Phys. 113:595–610 to the case of the pfaffian ensembles.
A spectroscopic CMOS photodetector for use with a cell-based biosensor

Spectroscopic photodetectors have been fabricated in a standard CMOS process. These photodetectors are designed to distinguish between two different fluorescent markers. They have applications in nucleic acid analysis, cell-based biosensors and tissue based-biosensors.
Control of cooperative multiple flexible joint robots

The problem of controlling multiple flexible joint robots during cooperative manipulation of a rigidly grasped common load (denoted as the CMFJR problem) is addressed. The dynamic model of the CMFJR shows the interaction between the manipulators in the closed chain is analogous to a single manipulator interacting with frictionless (algebraic constraint) surface, while in motion along the surface. It is assumed that each flexible joint robot is equipped with joint velocity and position sensors and also actuator mounted position and velocity sensors. It is shown that it is not necessary to employ force sensors mounted on the robot wrist in order to track a desired load trajectory and an internal force trajectory. The transient response of the position error and the internal force error can be arbitrarily assigned even though the force sensors are not employed. >
Errors in completion of referrals among older urban adults in ambulatory care.

Rationale, aims and objectives Clinical care often requires referrals, but many referrals never result in completed evaluations. We determined the extent to which referral-based consultations were completed in a US medical institution. Factors associated with completion were identified. Method In a cross-sectional analysis, we analysed billing records and electronic and paper-based medical records for patients aged 65 years or older receiving health care between July 2000 and June 2002 in an integrated, urban, tax-supported medical institution on an academic campus.All referrals in ambulatory care, scheduling of consultation within 180 days, and completion were assessed. We conducted a multivariate survival analysis to identify factors associated with completion. Results We identified 6785 patients with encounters. Mean age was 72 years, and, of the participants, 66% were women, 55% were African-American and 32% were Medicaid eligible. Of the 81% with at least one primary-care visit in ambulatory care, 63% had at least one referral. About 8% of referrals required multiple orders before an appointment was scheduled. Among 7819 orders for specialty consultation in ambulatory care, 71% led to appointments, and 70% of appointments were kept (completed = 0.71*0.70 or 50%). Scheduling of consultations varied (12% to 90%) by specialty. Medicare, singular orders, location of referral and lack of hospitalization were independently significantly associated with scheduling of appointments. Conclusions Among older adults studied, half of medical specialty referrals were not completed. Multiple process errors, including missing information, misguided referrals and faulty communications, likely contribute to these results. Information systems offer important opportunities to improve the referrals process.
The power spectrum of galaxies in the 2dF 100k redshift survey

We compute the real-space power spectrum and the redshift-space distortions of galaxies in the 2dF 100k galaxy redshift survey using pseudo-Karhunen-Loeve eigenmodes and the stochastic bias formalism. Our results agree well with those published by the 2dFGRS team, and have the added advantage of producing easy-to-interpret uncorrelated minimum-variance measurements of the galaxy-galaxy, galaxy-velocity and velocity-velocity power spectra in 27 k-bands, with narrow and well-behaved window functions in the range 0.01 h Mpc −1 0.4 and the redshift-distortion parameter β = 0.49 ± 0.16 for r = 1( β = 0.47 ± 0.16 without finger-of-god compression). Since this is an apparent-magnitude limited sample, luminosity-dependent bias may cause a slight red-tilt in the power spectrum. A battery of systematic error tests indicate that the sur- vey is not only impressive in size, but also unusually clean, free of systematic errors at the level to which our tests are sensitive. Our measurements and window functions are available at http://www.hep.upenn.edu/∼max/2df.html together with the survey mask, radial selection function and uniform subsample of the survey that we have constructed.
Nitridation Kinetics and Thermodynamics of Silicon Powder Compacts

The nitridation kinetics of Si powder compacts were studied by measuring the flow rate dependence of N2 and N2–H2 gas mixtures during slow heating of Si compacts while simultaneously monitoring the oxygen partial pressure of the egress gas. The reaction was found to occur in two distinct stages. In pure nitrogen the initial stage was interpreted in terms of devitrification of the native silica layer, catalyzed by Fe impurities, and the exposure of the underlying Si. The reaction sequence at that point has been unequivocally shown to be followed by the formation of oxynitride according to as evidenced by a large increase in the oxygen partial pressure simultaneously with the onset of the initial stage. In the absence of hydrogen, both reactions are rapidly suppressed as the oxygen liberated competes with the nitrogen for the exposed silicon surface and reoxidizes it. However, in the presence of hydrogen, the oxygen liberated reacts with the hydrogen and prevents the reoxidation of the Si. The net reaction in this case is and/or with the second reaction being thermodynamically favored. The main nitridation reaction occurring between 1300° and 1400°C appears to be diffusion controlled and depends on the nature of the passivating layer that forms during the initial stage.
Predicted Effects of Bearing Sump and Injection Pressures on Oil Labyrinth Leakage

New information and an enhanced understanding concerning the oil vapor contaminant leaking through nonflooded oil labyrinth seals are provided. The results were obtained using a finite volume Navier-Stokes computer code that was extended to include the concentration transport equation. The minimum (i.e., critical) pressure and flow rate at which uncontaminated buffer gas must be injected to prevent oil vapor from leaking to the process gas was determined for a range of seal geometries and operating conditions. It was found that the variation of the critical buffer-gas injection pressure with bearing gas and process gas pressures. for example, was surprisingly small for the cases considered. In addition, the bearing gas and oil vapor flow rates for a wide range of bearing and injection (where present) pressures and geometries were determined for both buffered as well as nonbuffered seals.
Harmonic measurements: current and voltage transducers

Summary form only given. At the National Research Council of Canada, special current and voltage transducers have been developed to accurately measure harmonics in power systems. An overview of the development of these special transducers with a wide dynamic and frequency range of operation are presented. The transducers include two-stage and electronically-aided instrument transformers, openable-core AC and AC/DC current transformers, multi-stage clamp-on current transformers, and current-comparator-based current and voltage transducers.
Investigation of Maillard reaction products using 15N isotope studies and analysis by electrospray ionization-mass spectrometry.

Structural characterization of reaction products of Maillard Chemistry has proved to be rather challenging. This can be directly attributed to the extreme complexity of product reaction mixtures that are known to range from small organic molecules to extremely large polymers. In addition, contemporary analytical techniques have been significantly challenged by the hydrophilic nature of advanced glycation endproducts (AGEs). Recently, methods such as on-line capillary electrophoresis-electrospray ionization-mass spectrometry (CE-MS) have emerged to provide a means of structurally characterizing molecules of extreme hydrophilicity. However, while this technique provides a means to identify such molecules, it is often difficult to differentiate products of ion/molecule reactions that can occur in the interface from authentic Maillard reaction products (MRPs). These artifacts are misleading, and lead to erroneous conclusions regarding solution composition. In the present study, we have prepared MRPs by reaction of 5-hydroxymethylfurfural (5-HMF) separately with 14N-glycine and 15N-glycine. CE-MS analysis of a 50:50 (vv) mixture of these solutions readily identifies product of ion/molecule reactions by a multiplicity of isotopes that fit a simple binomial expansion statistical output. By contrast, the mass spectrum of a MRP present in a preformed mixture of isotopically pure reaction products is much simpler. Such spectra display two responses (one for each isotope) that are separated by a mass number that directly corresponds to the number of nitrogen atoms present in the MRP. In addition, tandem mass spectrometric analysis of both of the isotopically pure MRPs aids the structural characterization of molecules of interest. Each fragment ion increases in mass by the number of nitrogen atoms it contains in the spectrum of the 15N labeled MRP. This strategy is demonstrated by the detection and structural characterization of 2-formyl-5-(hydroxy-methyl)pyrrole-1-acetic acid.
Throughput optimal switching in multi-channel WLANs

We observe that in a multi-channel system, an opportunistic channel access scheme that solely focuses on channel quality sensing measured by received SNR may induce users to use channels that, while providing better signals, are more congested. Ultimately the notion of channel quality should include both the signal quality and the level of congestion, and a good multi-channel access scheme should take both into account in deciding which channel to use and when. Motivated by this, we focus on the congestion aspect and examine what type of dynamic channel switching schemes may result in the best system throughput performance. Specifically we derive the stability region of a multi-user multi-channel WLAN system and determine the throughput optimal channel switching scheme within a certain class of schemes.