cssi/SciSciGPT-SciSciNet huggingface dataset:
Polypeptoids: a model system to study the effect of monomer sequence on polymer properties and self-assembly

As the ability to control the monomer sequence of synthetic polymers increases, new relationships between sequence, polymer structure, and functional properties are being discovered. Recent advances in the sequence control of traditional copolymers, such as polyethylenes and polystyrenes, have led to well controlled primary structures ranging from periodic to more precise sequences. As a result, this unprecedented control in the chemical structure of the polymer has necessitated a reexamination of the role of monomer sequence on polymer properties, such as crystallization and self-assembly. In this review, we summarize the developments in establishing a relationship between a polymer’s sequence and its properties, and we focus on one sequence-specific polymer system in particular: N-substituted glycines, or polypeptoids. Polypeptoid self-assembly has demonstrated remarkably tunable, hierarchical structures, and through this lens, we look to the future “designability” of sequence-specific polymers in general.
A Decision Model to Assess Cattle Feeding Price Risk

Traditional break-even/fed cattle price projections do not provide adequate risk information to feeders, investors, lenders, and other stakeholders interested in cattle feeding decisions. The objectives of this study were two-fold: 1) develop a spreadsheet model that could estimate the net income distribution surrounding a cattle placement decision based on historical errors of futures based price forecasts, and 2) determine whether information generated from the model can be used to improve placement and marketing decisions. To accomplish objective 1, model was developed that could estimate the income distribution around a pen of cattle under a cash speculating and short hedge pricing strategy. Distribution estimates were based on 7 alternative forecast horizons and were derived from historical forecast errors. To accomplish objective 2, decision rules were developed that allow the feeder to specify the maximum probability he/she is willing to risk losing a specified level of income. These decision rules were compared to random and naive decision rules by simulating the outcomes over 168 discrete six months feeding periods between 1987 and 2000. Risk averse decision rules were successful in signaling highly unprofitable feeding periods, but also filtered out highly profitable feeding periods.
Decay of Wake Vortices of Large Aircraft

A brief summary of previous works is followed by an in-depth analysis of velocities, circulations, and decay histories of a number of trailing vortices generated by large aircraft during field tests in Memphis, Tennessee. The results suggest that the decay of trailing vortices is governed by the mutual straining of vortices; intermittent exchange of mass, momentum, and vorticity across the core boundary; rotational damping and restructuring of turbulence in the core; stretching of large turbulent structures, turbulent diffusion, and the interaction of oppositely signed vorticity in the overlapping regions of the vortex pair; and the draining of vorticity from the Kelvin oval
Thermodynamics of lattice QCD with massless quarks and chiral 4-fermion interactions.

N{sub f} = 2 lattice QCD with massless quarks and a weak 4-fermion interaction appears to have the expected second order transition, at least for N{sub t} {ge} 6. More work is needed to clarify the N{sub t} = 4 case. With more statistics the N{sub t} = 6 simulations should produce an accurate determination of the critical exponent {beta}{sub m}. Moving to finite mass at {beta} = {beta}{sub c} should allow an accurate determination of {sigma}. Hadronic screening masses need further analysis. Other order parameters remain to be analyzed. Unfortunately, there is no obvious way to include 4-fermion interactions with full SU(2) x SU(2) chiral flavor symmetry.
The Importance of Population Growth and Regulation in Human Life History Evolution

Explaining the evolution of human life history traits remains an important challenge for evolutionary anthropologists. Progress is hindered by a poor appreciation of how demographic factors affect the action of natural selection. I review life history theory showing that the quantity maximized by selection depends on whether and how population growth is regulated. I show that the common use of R, a strategy’s expected lifetime number of offspring, as a fitness maximand is only appropriate under a strict set of conditions, which are apparently unappreciated by anthropologists. To concretely show how demography-free life history theory can lead to errors, I reanalyze an influential model of human life history evolution, which investigated the coevolution of a long lifespan and late age of maturity. I show that the model’s conclusions do not hold under simple changes to the implicitly assumed mechanism of density dependence, even when stated assumptions remain unchanged. This analysis suggests that progress in human life history theory requires better understanding of the demography of our ancestors.
Using Ancient Samples in Projection Analysis

Projection analysis is a tool that extracts information from the joint allele frequency spectrum to better understand the relationship between two populations. In projection analysis, a test genome is compared to a set of genomes from a reference population. The projection's shape depends on the historical relationship of the test genome's population to the reference population. Here, we explore in greater depth the effects on the projection when ancient samples are included in the analysis. First, we conduct a series of simulations in which the ancient sample is directly ancestral to a present-day population (one-population model), or the ancient sample is ancestral to a sister population that diverged before the time of sampling (two-population model). We find that there are characteristic differences between the projections for the one-population and two-population models, which indicate that the projection can be used to determine whether a test genome is directly ancestral to a present-day population or not. Second, we compute projections for several published ancient genomes. We compare two Neanderthals and three ancient human genomes to European, Han Chinese and Yoruba reference panels. We use a previously constructed demographic model and insert these five ancient genomes to assess how well the observed projections are recovered.
Star formation in mergers and interacting galaxies: gathering the fuel

Selected results from recent studies of star formation in galaxies at different stages of interaction are reviewed. Recent results from the Spitzer Space Telescope are highlighted. Ideas on how large-scale driving of star formation in interacting galaxies might mesh with our understanding of star formation in isolated galaxies and small scale mechanisms within galaxies are considered. In particular, there is evidence that on small scales star formation is determined by the same thermal and turbulent processes in cool compressed clouds as in isolated galaxies. If so, this affirms the notion that the primary role of large-scale dynamics is to gather and compress the gas fuel. In gas-rich interactions this is generally done with increasing efficiency through the merger process.
An ADH1B variant and peer drinking in progression to adolescent drinking milestones: evidence of a gene-by-environment interaction.

BACKGROUND: Adolescent drinking is an important public health concern, one that is influenced by both genetic and environmental factors. The functional variant rs1229984 in alcohol dehydrogenase 1B (ADH1B) has been associated at a genome-wide level with alcohol use disorders in diverse adult populations. However, few data are available regarding whether this variant influences early drinking behaviors and whether social context moderates this effect. This study examines the interplay between rs1229984 and peer drinking in the development of adolescent drinking milestones. METHODS: One thousand five hundred and fifty European and African American individuals who had a full drink of alcohol before age 18 were selected from a longitudinal study of youth as part of the Collaborative Study on the Genetics of Alcoholism (COGA). Cox proportional hazards regression, with G × E product terms in the final models, was used to study 2 primary outcomes during adolescence: age of first intoxication and age of first DSM-5 alcohol use disorder symptom. RESULTS: The minor A allele of rs1229984 was associated with a protective effect for first intoxication (HR = 0.56, 95% CI 0.41 to 0.76) and first DSM-5 symptom (HR = 0.45, 95% CI 0.26 to 0.77) in the final models. Reporting that most or all best friends drink was associated with a hazardous effect for first intoxication (HR = 1.81, 95% CI 1.62 to 2.01) and first DSM-5 symptom (HR = 2.17, 95% 1.88 to 2.50) in the final models. Furthermore, there was a significant G × E interaction for first intoxication (p = 0.002) and first DSM-5 symptom (p = 0.01). Among individuals reporting none or few best friends drinking, the ADH1B variant had a protective effect for adolescent drinking milestones, but for those reporting most or all best friends drinking, this effect was greatly reduced. CONCLUSIONS: Our results suggest that the risk factor of best friends drinking attenuates the protective effect of a well-established ADH1B variant for 2 adolescent drinking behaviors. These findings illustrate the interplay between genetic and environmental factors in the development of drinking milestones during adolescence. Language: en
The Oaxaca decomposition generalized to a continuous group variable

Abstract Almost universally, the Oaxaca (1973) decomposition is used to compare the outcomes between two discrete groups, e.g., black and white. In many applications, however, groups are not readily divided into discrete bins. The purpose of this paper is to extend the Oaxaca decomposition to examine differences amongst groups that are most naturally modeled as at points in a continuum. The gap can vary by values of the group variable.
Condensed Matter and AdS/CFT

I review two classes of strong coupling problems in condensed matter physics, and describe insights gained by application of the AdS/CFT correspondence. The first class concerns non-zero temperature dynamics and transport in the vicinity of quantum critical points described by relativistic field theories. I describe how relativistic structures arise in models of physical interest, present results for their quantum critical crossover functions and magneto-thermoelectric hydrodynamics. The second class concerns symmetry breaking transitions of two-dimensional systems in the presence of gapless electronic excitations at isolated points or along lines (i.e. Fermi surfaces) in the Brillouin zone. I describe the scaling structure of a recent theory of the Ising-nematic transition in metals, and discuss its possible connection to theories of Fermi surfaces obtained from simple AdS duals.
A serendipitous discovery: nickel catalyst for the cycloaddition of diynes with unactivated nitriles.

Xanted Nickel! The catalytic combination of Ni(COD)2 and Xantphos was used to access pyridines. The reaction proceeds under ambient conditions to provide excellent yields of products. Comparison of this catalyst with the other state-of-the-art catalysts is also provided.
Species-specific densities of states of Ga and As in the chemisorption of oxygen on GaAs(110)

Auger line-shape measurements have been made to extract the variation in the local charge distribution around Ga and As sites for chemisorption of oxygen on cleaved and sputter-etched GaAs(110). A significant variation with changing oxygen coverage is observed in the Ga spectrum, with a much more subtle change in the As spectrum. The kinetics of oxygen chemisorption on the sputter-etched surface is much more rapid than that on the cleaved surface. The line-shape changes induced by oxygen on the two surfaces are, however, similar. Conclusions on the nature of the bonding and on the mechanism for adsorption at both low and high coverages are drawn.
Security analysis in role-based access control

The administration of large role-based access control (RBAC) systems is a challenging problem. In order to administer such systems, decentralization of administration tasks by the use of delegation is an effective approach. While the use of delegation greatly enhances flexibility and scalability, it may reduce the control that an organization has over its resources, thereby diminishing a major advantage RBAC has over discretionary access control (DAC). We propose to use security analysis techniques to maintain desirable security properties while delegating administrative privileges. We give a precise definition of a family of security analysis problems in RBAC, which is more general than safety analysis that is studied in the literature. We show that two classes of problems in the family can be reduced to similar analysis in the RT[L∩] role-based trust-management language, thereby establishing an interesting relationship between RBAC and the RT framework. The reduction gives efficient algorithms for answering most kinds of queries in these two classes and establishes the complexity bounds for the intractable cases.
The Welfare Economics of Default Options in 401(k) Plans

Default contribution rates for 401(k) pension plans powerfully influence choices. Potential causes include opt-out costs, procrastination, inattention, and psychological anchoring. Using realistically parameterized models, we show how the optimal default, the magnitude of the welfare effects, and the degree of normative ambiguity depend on the behavioral model, the scope of the choice domain deemed welfare-relevant, the use of penalties for passive choice, and other 401(k) plan features. While results are theory-specific, our analysis provides reasonably robust justifications for setting the default either at the highest contribution rate matched by the employer or�contrary to common wisdom�at zero. (JEL D14, D91, J26, J32)
Tools for Change: An Examination of Transformative Learning and Its Precursor Steps in Undergraduate Students

In this quantitative study of college students spanning three waves, the 10 theoretical precursor steps of transformational learning did predict its occurrence. The most consistent predictor was the step of reflection. Maturity and ethnicity also showed a predictive value, but college major was not a significant differentiator for transformative learning.
Control systems curriculum national survey

The IEEE Control Systems Society Education Committee conducted a curriculum survey on control education in 1990-1991. Out of 224 schools contacted, 143 schools responded. The results of the survey are reported in this paper. >
Present status and future prospects for a Higgs boson discovery at the Tevatron and LHC

Discovering the Higgs boson is one of the primary goals of both the Tevatron and the Large Hadron Collider (LHC). The present status of the Higgs search is reviewed and future prospects for discovery at the Tevatron and LHC are considered. This talk focuses primarily on the Higgs boson of the Standard Model and its minimal supersymmetric extension. Theoretical expectations for the Higgs boson and its phenomenological consequences are reviewed.
Thermodynamic Equilibrium-Air Correlations for Flowfield Applications

Equilibrium-air thermodynamic correlations have been developed for flowfield calculation procedures. A comparison between the postshock results computed by the correlation equations and detailed chemistry calculations is very good. The thermodynamic correlations are incorporated in an approximate in viscid flowfield code with a convective heating capability for the purpose of defining the thermodynamic environment through the shock layer. Comparisons of heating rates computed by the approximate code and a viscous-shock-layer method are good. In addition to presenting the thermodynamic correlations, the impact of several viscosity models on the convective heat transfer is demonstrated.
Risk Taking Propensity of Entrepreneurs

The risk taking propensities of entrepreneurs of new ventures were objectively obtained using the Kogan- Wallach choice dilemmas questionnaire and were compared to those of managers and to normative data developed for the measurement instrument. The findings suggest that risk taking propensity may not be a distinguishing characteristic of entrepreneurs. They refute assumptions based on research that has been subjective and noncomparative and that used established entrepreneurs.
Adaptive compliant motion control of manipulators without velocity measurements

This paper presents two adaptive schemes for compliant motion control of uncertain manipulators: an adaptive impedance controller and an adaptive position/force controller. The proposed controllers are very general and computationally efficient, need virtually no information regarding the manipulator dynamic model or the environment, and require only position and force measurements for implementation. It is shown that the schemes ensure semiglobal uniform boundedness of all signals in the presence of bounded disturbances, and that the ultimate size of the system errors can be made arbitrarily small. The capabilities of the proposed control strategies are illustrated though both computer simulations and laboratory experiments with a six degree-of-freedom (DOF) IMI Zebra Zero manipulator.
Voltage and Current-Programmed Modes in Control of the Z-Source Converter

The Z-source converter (ZSC) is an alternative power conversion topology that can both buck and boost the input voltage using passive components with improved reliability. Dynamic modeling of the ZSC from different perspectives has been studied. So far, based on these models, the dc-link voltage is controlled using direct measurement, or through measurement of the capacitor voltage. In this paper, two methods of dc-link voltage control of ZSC are analyzed and compared. Both methods are based on measuring the input voltage and state variables of the ZSC and designing a compensator based on the converter state space averaged model. Voltage mode (VM) and current-programmed mode (CPM) controls are derived based on the ideal small-signal model of the Z-source network with inductive loading. Nonminimum phase characteristics caused by the right half-plane zero in the control-to-capacitor-voltage transfer function are minimized by designing proper compensators in both VM and CPM controls. In CPM, since the order of the system reduces by one, it is possible to achieve similar dynamic performance with a simpler compensator. Performance of both control methods of the compensated ZSC are verified by simulation and experimental results for input and load disturbances.
Optimal signal design for estimation of correlated MIMO channels

We address signal design for optimal estimation of correlated multi-input multi-output (MIMO) channels using pilot signals, assuming knowledge of the second-order channel statistics at the transmitter. Assuming a block fading channel model and minimum mean square error (MMSE) estimation at the receiver, we design the transmitted signal to optimize two criteria: MMSE and the conditional mutual information between the MIMO channel and the received signal. Our analysis is based on the proposed virtual channel representation, however, it is generalized to other known channel models like the one in D.Shiu et al. [Mar. 2000]. We show that optimal signaling is in a block form, where the block length depends on the signal to noise ratio (SNR) as well as the channel correlation matrix. The block signal corresponds to transmitting beams in successive time intervals along a fixed virtual transmit angles, whose powers are determined by (non-identical) water filling arguments based on the optimization criteria. Our analysis effectively provides characterization of the dominant subspaces of the channel as a function of the SNR and the scattering environment, which is critical to achieving capacity and space-time code design. In particular, at low SNR the block length reduces to one and all the power is transmitted on the beam corresponding to the strongest transmit angle, while at high SNR the block length has a maximum length equal to the number of active virtual transmit angles and the power is assigned equally to all active transmit angles. Consequently, from a channel estimation viewpoint, a faster fading rate can be tolerated at low SNRs relative to higher SNRs.
On the asymptotic character of electromagnetic waves in a Friedmann–Robertson–Walker universe

Asymptotic properties of electromagnetic waves are studied within the context of Friedmann–Robertson–Walker (FRW) cosmology. Electromagnetic fields are considered as small perturbations on the background spacetime and Maxwell’s equations are solved for all three cases of flat, closed and open FRW universes. The asymptotic character of these solutions is investigated and their relevance to the problem of cosmological tails of electromagnetic waves is discussed.
Capital Market Regimes and Bank Structure in Europe

We hypothesize that fundamental features that distinguish European capital markets have predictably influenced emerging national differences in bank capitalization and loan growth. Using bank-level data from 13 European countries, 1998 to 2004, we find evidence of positive effects of “equity-friendly” market features on bank capitalization and positive effects of both “equity-friendly” and “credit-friendly” market features on loan growth. The findings are strongest in small banks and in banks with cooperative charters. Our results suggest that ongoing and prospective integration of European banking markets is mitigated by relatively static features of the equity and credit markets on which banks rely.
Policy Responses to Exchange-rate Movements

This paper examines policy responses to exchange-rate movements in a simple model of an open economy. The optimal response of monetary policy to an exchange-rate change depends on the source of the change: on whether the underlying shock is a shift in capital flows, manufactured exports, or commodity prices. The paper compares the model’s prescriptions to the policies of an actual central bank, the Bank of Canada. Finally, the paper considers the role of fiscal policy in an open economy. Coordinated fiscal and monetary responses to exchange-rate movements stabilize output at the sectoral as well as aggregate level.
SHOPPING EXTERNALITIES AND SELF-FULFILLING UNEMPLOYMENT FLUCTUATIONS

We propose a novel theory of self-fulfilling fluctuations in the labor market. A firm employing an additional worker generates positive externalities on other firms, because employed workers have more income to spend and have less time to shop for low prices than unemployed workers. We quantify these shopping externalities and show that they are sufficiently strong to create s complementarities in the employment decisions of different firms and to generate multiple rational expectations equilibria. Equilibria differ with respect to agents’ (rational) expectations about future unemployment. We show that negative shocks to agents’ expectations lead to fluctuations in vacancies, unemployment, labor productivity and the stock market that closely resemble those observed in the US during the Great Recession.
The Effects of Multipath and Fading on the Performance of Direct-Sequence CDMA Systems

We show the following results concerning the maximum number N max of simultaneous users supportable by an asynchronous direct-sequence code-division multiple-access (CDMA) system using DPSK. (a) For a network of single-path nonfading links in which all users' signals arrive at any receiver with equal energies, N max is 10-20 percent of the number of chips M in the system's codes at bit error rates of 10-3to 10-5. (b) If typical urban/suburban multipath and fading phenomena occur and no power control ameliorates them, N max falls to 1-5 percent of M even under the best of circumstances (availability of multipath diversity and ideal multipath combining receivers). (c) If the links consist mostly of only single fading paths and no power control is available, direct-sequence CDMA becomes unusable. Power-control policies can be devised to overcome shadowing (slow fading) or near/far problems, thus partially restoring the N max of (a). It is unlikely that power control will effectively combat fast fading, especially in single-path situations.
Structured porous materials via colloidal crystal templating: from inorganic oxides to metals

The formation of nanostructured materials by using colloidal crystals as templates is a relatively new but rapidly growing area of materials science. Colloid crystalline templates are three-dimensional close-packed crystals of submicrometer spheres, whose long-ranged ordered structure is replicated in a solid matrix, to yield materials with ordered pores. These materials hold promise for use as photonic crystals, advanced catalysts, and in a variety of other applications. Here we review the wide range of materials that have been made following the original synthesis of structured porous silica. This method has been recently modified to produce porous metals.
The KR-Benes network: a control-optimal rearrangeable permutation network

The Benes network has been used as a rearrangeable network for over 40 years, yet the uniform N(2 log N-1) control complexity of the N/spl times/N Benes is not optimal for many permutations. In this paper, we present a novel O(log N) depth rearrangeable network, called KR-Benes, that is permutation-specific control-optimal The KR-Benes routes every permutation with the minimal control complexity specific to that permutation and its worst-case complexity for arbitrary permutations is bounded by the Benes; thus, it replaces the Benes when considering control complexity/latency. We design the KR-Benes by first constructing a restricted 2log K+2 depth rearrangeable network called K-Benes for routing K-bounded permutations with control 2N log K, 0/spl les/K/spl les/N/4. We then show that the N/spl times/N Benes network itself (with one additional stage) contains every KR-Benes network as a subgraph and use this property to construct the KR-Benes network. With regard to the control-optimality of the KR-Benes, we show that any optimal network for rearrangeably routing K-bounded permutations must have depth 2log K+2 and, therefore, the K-Benes (and, hence, the KR-Benes) is optimal.
MAXIMUM LIKELIHOOD ESTIMATION OF LATENT AFFINE PROCESSES

This article develops a direct filtration-based maximum likelihood methodology for estimating the parameters and realizations of latent affine processes. Filtration is conducted in the transform space of characteristic functions, with a version of Bayes’ rule used for recursively updating the joint characteristic function of latent variables and the data conditional upon past data. An application to daily stock returns over 1953-96 reveals substantial divergences from EMM-based estimates; in particular, more substantial and time-varying jump risk. The implications for stock index options’ prices are discussed.
STRATEGIC RULES ON SPECULATION IN THE FOREIGN EXCHANGE MARKET

In this article we specify the conditions for profitable speculaion in the foreign exchange market with spot and forward contracts. We derive the unique strategic rules from the initial two-choice situations in a given environment. Finally, in a more complex structure involving covered arbitrage, speculative profits are computed with iterative plays. JEL classification: F310
Is FIRST J102347.6+003841 Really a Cataclysmic Binary?

The radio source FIRST J102347.6+003841 was presented as the first radio-selected cataclysmic variable star. In the discovery paper, Bond et al. (2002) show a spectrum consistent with a magnetic AM Her–type system, or polar, featuring strong Balmer lines, He I and He II emission lines, and a light curve with rapid, irregular flickering. In contrast, Woudt, Warner, and Pretorius found a smoothly varying light curve with a period near 4.75 hr and one minimum per orbit, indicating that the state of the system had changed dramatically. We present time-resolved spectra showing a superficially normal, mid-G type photosphere, with no detectable emission lines. The absorption-line radial velocity varies sinusoidally, with semiamplitude 268 ± 4 km s-1, on the orbital period, which is refined to 0.198094(2) days. At this orbital period, the secondary's spectral type is atypically early, suggesting an unusual evolutionary history. We also obtained photometry around the orbit in B, V, and I. The light curve resembles that observed by Woudt, Warner, and Pretorius, and the colors are modulated in a manner consistent with a heating effect. A simple illumination model matches the observations strikingly well, with a Roche lobe–filling secondary near Teff = 5650 K being illuminated by a primary with an isotropic luminosity of ~2 L⊙. The modest amplitude of the observed modulation constrains the orbital inclination i ~ 55° or less, unless the gravity darkening is artificially reduced. Combining the low i with the secondary's velocity amplitude gives a primary star mass above the Chandrasekhar limit when conventional gravity darkening is assumed. We consider the robustness of this conclusion and examine the possibility that the compact object in this system is not a white dwarf, in which case this is not actually a cataclysmic variable. On close examination, FIRST J102347.6+003841 defies easy classification.
Velocity analysis for transversely isotropic media

The main difficulty in extending seismic processing to anisotropic media is the recovery of anisotropic velocity fields from surface reflection data. We suggest carrying out velocity analysis for transversely isotropic (TI) media by inverting the dependence of P‐wave moveout velocities on the ray parameter. The inversion technique is based on the exact analytic equation for the normal‐moveout (NMO) velocity for dipping reflectors in anisotropic media. We show that P‐wave NMO velocity for dipping reflectors in homogeneous TI media with a vertical symmetry axis depends just on the zero‐dip value Vnmo(0) and a new effective parameter η that reduces to the difference between Thomsen parameters e and δ in the limit of weak anisotropy. Our inversion procedure makes it possible to obtain η and reconstruct the NMO velocity as a function of ray parameter using moveout velocities for two different dips. Moreover, Vnmo(0) and η determine not only the NMO velocity, but also long‐spread (nonhyperbolic) P‐wave moveout ...
Antegrade and retrograde endoscopic approach in the establishment of a neo-esophagus: a novel technique

Background Although total obstruction or secondary atresia of the esophagus is extremely rare, high-grade strictures are not uncommon. The retrograde approach was previously described to achieve dilation when the conventional antegrade method fails. Setting Gastroenterology laboratory in a tertiary referral center. Patient A 30-year-old man with congenital T-cell immunodeficiency had complete esophageal obstruction after a severe episode of cryptococcal meningitis that required prolonged nasogastric intubation. For the next 3 years, he had daily episodes of regurgitations and several hospitalizations for aspiration pneumonia. A barium study revealed a dilated megaesophagus, with no contrast reaching to the stomach. Intervention Initially, a new track was created by using access from above and below the obstruction. This was followed by placement of a self-expandable silicone stent after allowing sufficient time for the new track to mature. Main Outcome Measurements Restoration of esophageal continuity, which allowed resolution of the patient's aspiration pneumonia and resumption of oral feeding. Conclusions Complete esophageal obstruction after prolonged nasogastric intubation is a rare but serious complication. A novel endoscopic approach can be used to restore esophageal continuity, minimize complications, and avoid major reconstructive surgeries.
Measurement of Jet Modification at RHIC

Recent results from RHIC on high p ⊥ suppression and statistical jet reconstruction are presented. The results are discussed in context of the two prerequisites for QGP formation: high energy density and parton thermalization.
The Effectiveness of Monetary Policy Anchors: Firm-Level Evidence

Analyses of monetary policy posit that exchange-rate pegs, inflation targets, and central bank independence can help anchor private-sector inflation expec- tations+ Yet there are few direct tests of this argument+ We offer cross-national, micro- level evidence on the effectiveness of monetary anchors in controlling private-sector inflation concerns+ Using firm-level data from eighty-one countries ~approximately 10,000 firms!, we find evidence that "international" anchors ~exchange-rate commit- ments! correlate significantly with a substantial reduction in private-sector concerns about inflation while "domestic" anchors ~inflation targeting and central bank inde- pendence! do not+ Our conjecture is that private-sector inflation expectations are more responsive to exchange-rate anchors because they are more transparent, more con- straining, and more costly than domestic anchoring arrangements+ The literature on monetary policy highlights the role of monetary institutions in stabilizing private-sector inflation expectations+ Central bank independence ~CBI!, inflation targeting ~IT!, and fixed exchange rates ~pegs! are widely viewed as insti- tutions that have the capacity to mitigate private-sector concerns that policymak- ers will exploit them after they have locked in their price, wage, and investment decisions+ While other empirical research explores the institutional correlates of inflation and its variability—yielding mixed results—we use firm-level data in our study to directly assess the impact of monetary anchors on private-sector inflation concerns+ We find evidence that pegs mitigate firm owners' concerns with infla- tion, but that domestic anchors such as IT and CBI are uncorrelated with our micro- indicators of inflation expectations+ Considerable research has investigated the use of IT, CBI, and pegs as institu- tions that establish monetary policy credibility+ Whereas these anchors are expected,
The effect of massive neutrinos on the matter power spectrum

We investigate the impact of massive neutrinos on the distribution of matter in the semi-non-linear regime (0:1 < k < 0:6hMpc 1 ). We present a suite of large-scale N body simulations quantifying the scale dependent suppression of the total matter power spectrum, resulting from the free-streaming of massive neutrinos out of highdensity regions. Our simulations show a power suppression of 3:5 90 per cent at k 0:6hMpc 1 for total neutrino mass, m = 0:05 1:9 eV respectively. We also discuss the precision levels that future cosmological datasets would have to achieve in order to distinguish the normal and inverted neutrino mass hierarchies.
Reversal of the Regiochemistry in the Rhodium‐Catalyzed [4+3] Cycloaddition between Vinyldiazoacetates and Dienes

A regio-, diastereo-, and enantioselective [4+3] cycloaddition between vinylcarbenes and dienes has been achieved using the dirhodium tetracarboxylate catalyst [Rh2(S-BTPCP)4]. This methodology provides facile access to 1,4-cycloheptadienes that are regioisomers of those formed from the tandem cyclopropanation/Cope rearrangement reaction of vinylcarbenes with dienes.
The Path of Carbon in Photosynthesis

An overview is presented of photosynthesis and the problems involved in attempting to study and understand this process. The study of the order of appearance of the compounds in time and the methods of separation and analysis are discussed. About twenty compounds in the process of photosynthesis have been identified. Additional information was obtained which is more crucial in defining the path of carbon in photosynthesis. Degradative methods were devised which not only determined the compounds containing the radioactive carbon atoms, but also determined which atoms in the compounds are the radioactive ones.
Large and small artery compliance changes during hemodialysis.

Abstract Background: Cardiovascular disease is the major cause of mortality and morbidity in patients undergoing hemodialysis. Reduced arterial compliance is an independent predictor of cardiovascular mortality in end stage renal disease and can be measured noninvasively using pulse wave analysis technology. Methods: Ten chronic hemodialysis patients were evaluated using pulse wave analysis to determine large and small vessel compliance before hemodialysis, midway through the treatment, and at the end of the treatment. Serum calcium was measured before and after hemodialysis. Results: No significant changes in systolic blood pressure (BP), diastolic BP, pulse pressure, or heart rate occurred during hemodialysis. A significant decrease in small vessel compliance (C2) occurred during the treatment, with the mean C2 decreasing from 5.6 ± 2.7 mL/mm Hg × 10 predialysis to 3.3 ± 1.5 mL/mm Hg × 10 midway through the treatment ( P = .04) and to 3.9 ± 4.3 mL/mm Hg × 10 at the end of the dialysis treatment. There was no significant change in large vessel compliance (C1). Serum calcium increased significantly during the dialysis treatment from 8.0 ± 1.2 mg/dL to 9.8 ± 0.9 mg/dL ( P = .003). Conclusions: Significant decreases in small artery compliance occur without systolic or diastolic BP changes during routine hemodialysis. A significant increase in serum calcium also occurred during hemodialysis. Measurements of arterial compliance during hemodialysis may be an important tool to identify patients with vascular responses, which may place them at greater risk for cardiovascular disease.
Selective α-amination and α-acylation of esters and amides via dual reactivity of O-acylhydroxylamines toward zinc enolates

Selective α-amination and α-acylation of esters and amides have been developed, employing O-acylhydroxylamines as a dually reactive aminating and acylating reagent. Treatment of zinc enolates with O-acylhydroxylamines provides solely 1,3-dicarbonyl compounds under mild conditions. Introduction of a copper catalyst into the system shifts the reactivity entirely, yielding α-amination products exclusively.
Local Starbursts: Perspectives from the Optical

The optical regime is historically the best-studied wavelength range. Gas ionized by massive stars produces optical emission lines that have been used to derive indicators of star-formation rate, metallicity, dust reddening, and the ionization conditions of the interstellar medium. Absorption lines have been used to measure velocity dispersions, and the 4000 A break has been shown to be a useful indicator of the mean age of stellar populations. I briefly summarize some recent work done on, specifically, star-formation rate indicators, in view of their importance for understanding star-forming galaxies at high redshift.
Generalized approximate message passing for estimation with random linear mixing

We consider the estimation of a random vector observed through a linear transform followed by a componentwise probabilistic measurement channel. Although such linear mixing estimation problems are generally highly non-convex, Gaussian approximations of belief propagation (BP) have proven to be computationally attractive and highly effective in a range of applications. Recently, Bayati and Montanari have provided a rigorous and extremely general analysis of a large class of approximate message passing (AMP) algorithms that includes many Gaussian approximate BP methods. This paper extends their analysis to a larger class of algorithms to include what we call generalized AMP (G-AMP). G-AMP incorporates general (possibly non-AWGN) measurement channels. Similar to the AWGN output channel case, we show that the asymptotic behavior of the G-AMP algorithm under large i.i.d. Gaussian transform matrices is described by a simple set of state evolution (SE) equations. The general SE equations recover and extend several earlier results, including SE equations for approximate BP on general output channels by Guo and Wang.
Demanding to be Served : Holding Governments to Account for Improved Access

This paper presents an overview of the constitutional-legal provisions on access to services in developing countries and shows that rights to public services are not justice-able. It further documents the performance record to show that governments' response to such a weak accountability framework has been predictable - poor performance in service delivery with little accountability. The paper also shows that while there has not been a shortage of ideas on how to deal with this problem, most approaches have failed because they could not diagnose and deal with the underlying causes of government dysfunction. The paper presents an analytical perspective on understanding the causes of dysfunctional governance and the incentives and accountability regimes that have the potential to overcome this dysfunction. The paper also documents practices that have shown some promise in improving access. The paper then integrates ideas from successful practices with conceptual underpinnings for good governance and presents a citizen-centric (rights based) governance approach to access. It further explores how such a citizen empowerment and government accountability framework can be implemented in practice, especially in the context of developing countries, where most governments still operate in a command and control environment with little or no orientation to serve their people. It also presents ideas on how to overcome resistance to such reforms.
Resource-driven mission-phasing techniques for constrained agents in stochastic environments

Because an agent's resources dictate what actions it can possibly take, it should plan which resources it holds over time carefully, considering its inherent limitations (such as power or payload restrictions), the competing needs of other agents for the same resources, and the stochastic nature of the environment. Such agents can, in general, achieve more of their objectives if they can use -- and even create -- opportunities to change which resources they hold at various times. Driven by resource constraints, the agents could break their overall missions into an optimal series of phases, optimally reconfiguring their resources at each phase, and optimally using their assigned resources in each phase, given their knowledge of the stochastic environment. In this paper, we formally define and analyze this constrained, sequential optimization problem in both the single-agent and multi-agent contexts. We present a family of mixed integer linear programming (MILP) formulations of this problem that can optimally create phases (when phases are not predefined) accounting for costs and limitations in phase creation. Because our formulations simultaneously also find the optimal allocations of resources at each phase and the optimal policies for using the allocated resources at each phase, they exploit structure across these coupled problems. This allows them to find solutions significantly faster (orders of magnitude faster in larger problems) than alternative solution techniques, as we demonstrate empirically.
Catalytic Kinetic Resolution of Biaryl Compounds

Biaryl compounds with axial chirality are very common in synthetic chemistry, especially in catalysis. Axially chiral biaryls are important due to their biological activities and extensive applications in asymmetric catalysis. Thus the development of efficient enantioselective methods for their synthesis has attracted considerable attention. This Minireview discusses the progress made in catalytic kinetic resolution of biaryl compounds and chronicles significant advances made recently in catalytic kinetic resolution of biaryl scaffolds.
A deeper understanding of white dwarf interiors

A detailed record of the physical processes that operate during post-main-sequence evolution is contained in the internal chemical structure of white dwarfs. Global pulsations allow us to probe the stellar interior through asteroseismology, revealing the signatures of prior nuclear burning, mixing and diffusion in these stars. I review the rapid evolution of structural models for helium atmosphere variable (DBV) white dwarfs over the past five years, and I present a new series of model fits using recent observations to illustrate the relative importance of various interior structures. By incorporating physically motivated C/O profiles into double-layered envelope models for the first time, I identify an optimal asteroseismic model that agrees with both diffusion theory and the expected nuclear burning history of the progenitor. I discuss the implications of this fundamental result, and I evaluate the prospects for continued progress in the future.
The Consequences of Rivalry: Explaining Insurgent Violence Using Fuzzy Sets

The author presents a unique theory of insurgent group behavior using a fuzzy-set approach. In contrast to arguments that place the culpability of insurgent group violence toward noncombatants in t...
The complex of non-crossing diagonals of a polygon

Given a convex n-gon P in R^2 with vertices in general position, it is well known that the simplicial complex @q(P) with vertex set given by diagonals in P and facets given by triangulations of P is the boundary complex of a polytope of dimension n-3. We prove that for any non-convex polygonal region P with n vertices and h+1 boundary components, @q(P) is a ball of dimension n+3h-4. We also provide a new proof that @q(P) is a sphere when P is convex with vertices in general position.
Discourses of difference: civilians, combatants, and compliance with the laws of war

Why have President Bush and his administration consistently, and publicly, stated their commitment to fully comply with the laws of war protecting civilians while, simultaneously, refusing to fully comply with the laws of war protecting prisoners of war? How do we understand President Bush and his administration’s unquestioning acceptance of the protection of civilians, but the rejection of the same for prisoners of war? Are the strategic and normative costs of each so dissimilar as to justify this difference? Considering the recent expose of abuses and torture of prisoners of war held in both Iraq and Cuba, the answers to these questions are not merely academic.
Prediction of protein retention times in anion-exchange chromatography systems using support vector regression.

Quantitative Structure-Retention Relationship (QSRR) models are developed for the prediction of protein retention times in anion-exchange chromatography systems. Topological, subdivided surface are...
Spin Dynamics in a Tunnel Junction between Ferromagnets

The dynamics of a single spin embedded in the tunnel junction (quantum point contact) between ferromagnets is addressed. Using the Keldysh technique, we derive a quantum Langevin equation. As a consequence of the spin-polarization in the leads, the spin displays a rich and unusual dynamics. Parallel configured and equally strong magnetic moments in the leads yield an ordinary spin precession with a Larmor frequency given by the effective magnetic field. Unequal and/or non-parallel configured magnetization, however, causes nutation of the spin in addition to the precession. Our predictions may be directly tested for macroscopic spin clusters.
Radiative Cooling of a Hydrogen Plasma in a Shock Tube

A method of computing radiative cooling of a hydrogen plasma, assuming quasi-isothermal radiative transfer, is described. In this approach, the flux divergence is evaluated using the isothermal solution to the equation of radiative transfer. With this simplification, coupled with the exponential approximation, nongray radiative cooling calculations in geometrically complex flowfields can be easily made. A comparison with nonisothermal calculations for a plane parallel slab indicates good agreement for temperature gradients up to 300 K/cm. Further comparisons with shock-tube data obtained in the Jet Propulsion Laboratory (JPL) high-performance shock-tube facility are presented.