cssi/SciSciGPT-SciSciNet huggingface dataset:
Public Choice and Public Life

This chapter attempts to impose analytical order on my 6 years as a city council member and 4 years as mayor of a small Utah city. It traces how Buchanan and Tullock affected my academic and public life and the difficulties of being a public choice mayor. The Buchanan/Tullock enterprise provides insights to how people act badly when trying to act through government and do good when acting in voluntary small groups.
The magnitude of the stereodirecting effect of an allylic alkoxy-substituent in an amidomercuration cyclization

Abstract A surprisingly large stereodirecting effect for the allylic alkoxy-substituent (> 4 kcal/mol) is revealed in the amidomercuration cyclization of an unsaturated amidal in which the stereodirecting effect of the allylic alkoxy-substituent competes against the stcreodirecting effect of a stereogenic amidal center.
The color of the Kuiper belt Core

Abstract Recent dynamical analyses of the Kuiper belt have introduced a rigorous classification scheme, determined the mean orbital plane, and identified “Core” and “Halo” populations as a function of inclination with respect to this plane (Elliot, J.L., Kern, S.D., Clancy, K.B., Gulbis, A.A.S., Millis, R.L., Buie, M.W., Wasserman, L.H., Chiang, E.I., Jordan, A.B., Trilling, D.E., Meech, K.J., 2005. Astron. J. 129, 1117–1162). Here, we use new observations and existing data to investigate the colors of Kuiper belt objects (KBOs) within this framework. With respect to the bulk KBO color distribution (all objects for which we have B – V and V – R colors; median B – R = 1.56 ), we find that the population of objects classified following (Elliot, J.L., Kern, S.D., Clancy, K.B., Gulbis, A.A.S., Millis, R.L., Buie, M.W., Wasserman, L.H., Chiang, E.I., Jordan, A.B., Trilling, D.E., Meech, K.J., 2005. Astron. J. 129, 1117–1162) as Classical tends to be red ( B – R > 1.56 ) while the Scattered Near population is mostly neutral ( B – R 1.56 ). Colors of Scattered Extended and Resonant objects are consistent with the bulk distribution. Separating objects into specific resonances demonstrates that the color of the Resonant sample is dominated by KBOs in the 3:2 resonance, which is consistent with previous findings. Unlike the objects in the 3:2 resonance, however, the majority of objects in the 5:2 resonance are neutral and all but one of the objects in the 4:3, 5:3, 7:4, 2:1, and 7:3 resonances are red. In particular, the objects in the 7:4 resonance are remarkably red. We find that the colors of KBOs in the Core (low-inclination) and Halo (high-inclination) are statistically different, with Core objects being primarily red and Halo objects having a slight tendency to be neutral. Notably, virtually all of the non-Resonant Core objects are red. This combination of low inclination, unperturbed orbits and red colors in the Core may be indicative of a relic grouping of objects.
CONSTRUCTING REGULAR ULTRAFILTERS FROM A MODEL-THEORETIC POINT OF VIEW

This paper contributes to the set-theoretic side of understanding Keisler's order. We consider properties of ultralters which aect saturation of unstable theories: the lower conality lcf(@0,D) of @0 modulo D, saturation of the minimum unstable theory (the random graph), exi- bility, goodness, goodness for equality, and realization of symmetric cuts. We work in ZFC except when noted, as several constructions appeal to complete ultralters thus assume a measurable car- dinal. The main results are as follows. First, we investigate the strength of exibility, known to be detected by non-low theories. Assuming� > @0 is measurable, we construct a regular ultralter on � � 2 � which is exible but not good, and which moreover has large lcf(@0) but does not even saturate models of the random graph. This implies (a) that exibility alone cannot characterize saturation of any theory, however (b) by separating exibility from goodness, we remove a main obstacle to proving non-low does not imply maximal. Since exible is precisely OK, this also shows that (c) from a set-theoretic point of view, consistently, ok need not imply good, addressing a prob- lem from Dow 1985. Second, under no additional assumptions, we prove that there is a loss of saturation in regular ultrapowers of unstable theories, and also give a new proof that there is a loss of saturation in ultrapowers of non-simple theories. More precisely, for D regular onand M a model of an unstable theory, M � /D is not (2 � ) + -saturated; and for M a model of a non-simple theory and � = � <� , M � /D is not � ++ -saturated. In the third part of the paper, we investigate realization and omission of symmetric cuts, signicant both because of the maximality of the strict order property in Keisler's order, and by recent work of the authors on SOP2. We prove that if D is a �-complete ultralter on �, any ultrapower of a suciently saturated model of linear or der will have no (�,�)-cuts, and that ifD is also normal, it will have a (� + ,� + )-cut. We apply this to prove that for any n < !, assuming the existence of n measurable cardinals below �, there is a regular ultralter D onsuch that any D-ultrapower of a model of linear order will haven alternations of cuts, as dened below. Moreover, D will � + -saturate all stable theories but will not (2 � ) + -saturate any unstable theory, whereis the smallest measurable cardinal used in the construction.
Wind Tunnel Wall Effects in a Linear Oscillating Cascade

Experiments in a linear oscillating cascade reveal that the wind tunnel walls enclosing the airfoils have, in some cases, a detrimental effect on the oscillating cascade aerodynamics. In a subsonic flow field, biconvex airfoils are driven simultaneously in harmonic, torsion-mode oscillations for a range of interblade phase angle values. It is found that the cascade dynamic periodicity - the airfoil to airfoil variation in unsteady surface pressure - is good for some values of interblade phase angle but poor for others. Correlation of the unsteady pressure data with oscillating flat plate cascade predictions is generally good for conditions where the periodicity is good and poor where the periodicity is poor. Calculations based upon linearized unsteady aerodynamic theory indicate that pressure waves reflected from the wind tunnel walls are responsible for the cases where there is poor periodicity and poor correlation with the predictions.
Efficient Generation of Jets from Magnetically Arrested Accretion on a Rapidly Spinning Black Hole

We describe global, 3D, time-dependent, non-radiative, general-relativistic, magnetohydrodynamic simulations of accreting black holes (BHs). The simulations are designed to transport a large amount of magnetic flux to the centre, more than the accreting gas can force into the BH. The excess magnetic flux remains outside the BH, impedes accretion, and leads to a magnetically arrested disc. We find powerful outflows. For a BH with spin parameter a = 0.5, the efficiency with which the accretion system generates outflowing energy in jets and winds is η ≈ 30 per cent. For a = 0.99, we find η ≈ 140 per cent, which means that more energy flows out of the BH than flows in. The only way this can happen is by extracting spin energy from the BH. Thus the a = 0.99 simulation represents an unambiguous demonstration, within an astrophysically plausible scenario, of the extraction of net energy from a spinning BH via the Penrose–Blandford–Znajek mechanism. We suggest that magnetically arrested accretion might explain observations of active galactic nuclei with apparent η ≈ few × 100 per cent.
A trio of dualities: Walls, trees and cascades

We study the RG flow of N = 1 world-volume gauge theories of D3-brane probes on certain singular Calabi-Yau threefolds. Taking the gauge theories out of conformality by introducing fractional branes, we compute the NSVZ beta-function and follow the subsequent RG flow in the cascading manner of Klebanov-Strassler. We study the duality trees that blossom from various Seiberg dualities and encode possible cascades. We observe the appearance of duality walls, a finite limit energy scale in the UV beyond which the dualization cascade cannot proceed. Diophantine equations of the Markov type characterize the dual phases of these theories. We discuss how the classification of Markov equations for different geometries into families relates the RG flows of the corresponding gauge theories.
A convenient asymmetric synthesis of pyrrolo[2,1-a]isoquinolines

Abstract A four-step synthesis of optically pure 6α-phenyl pyrroloisoquinolines from chiral formamidines has been accomplished.
Non-commutative Henselian rings

Abstract Non-commutative Henselian rings are defined and some basic properties of them are discussed. It is shown that a local ring which is complete in the topology defined by its maximal ideal is Henselian provided that it is almost commutative. Some examples of non-commutative Henselian rings are also given.
Algorithms, games, and the internet

If the Internet is the next great subject for Theoretical Computer Science to model and illuminate mathematically, then Game Theory, and Mathematical Economics more generally, are likely to prove useful tools. In this talk I survey some opportunities and challenges in this important frontier.
Topological Digital Topology

The usefulness of topology in science and mathematics means that topological spaces must be studied, and computers should be used in this study. We discuss how many useful spaces (including all compact Hausdorff spaces) can be approximated by finite spaces, and these finite spaces are completely determined by their specialization orders. As a special case, digital n-space, used to interpret Euclidean n-space and in particular, the computer screen, is also dealt with in terms of the specialization. Indeed, algorithms written using the specialization are comparable in difficulty, storage usage and speed to those which use the traditional (8,4), (4,8) and (6,6) adjacencies, and are of course completely representative of the spaces.
Assortment Planning and Inventory Decisions Under a Locational Choice Model

We consider a single-period assortment planning and inventory management problem for a retailer, using a locational choice model to represent consumer demand. We first determine the optimal variety, product location, and inventory decisions under static substitution, and show that the optimal assortment consists of products equally spaced out such that there is no substitution among them regardless of the distribution of consumer preferences. The optimal solution can be such that some customers prefer not to buy any product in the assortment, and such that the most popular product is not offered. We then obtain bounds on profit when customers dynamically substitute, using the static substitution for the lower bound, and a retailer-controlled substitution for the upper bound. We thus define two heuristics to solve the problem under dynamic substitution and numerically evaluate their performance. This analysis shows the value of modeling dynamic substitution and identifies conditions in which the static substitution solution serves as a good approximation.
Semantics of transactional memory and automatic mutual exclusion

Software Transactional Memory (STM) is an attractive basis for the development of language features for concurrent programming. However, the semantics of these features can be delicate and problematic. In this article we explore the trade-offs semantic simplicity, the viability of efficient implementation strategies, and the flexibility of language constructs. Specifically, we develop semantics and type systems for the constructs of the Automatic Mutual Exclusion (AME) programming model; our results apply also to other constructs, such as atomic blocks. With this semantics as a point of reference, we study several implementation strategies. We model STM systems that use in-place update, optimistic concurrency, lazy conflict detection, and rollback. These strategies are correct only under nontrivial assumptions that we identify and analyze. One important source of errors is that some efficient implementations create dangerous “zombie” computations where a transaction keeps running after experiencing a conflict; the assumptions confine the effects of these computations.
Attention-Deficit/Hyperactivity Disorder: Diagnosis, Lifespan, Comorbidities, and Neurobiology

In this report, we provide an evidence-based overview of attention-deficit/hyperactivity disorder (ADHD), including diagnosis, prevalence, developmental expression of symptoms, persistence, the heterogeneity of functional outcome, impairment in afflicted adults, psychiatric comorbidity, pathophysiology, genetics, psychosocial and biologic risk factors, and neurobiology. Attention-deficit/hyperactivity disorder is an early-onset, highly prevalent neurobehavioral disorder, with genetic, environmental, and biologic etiologies, that persists into adolescence and adulthood in a sizable majority of afflicted children of both sexes. It is characterized by behavioral symptoms of inattention, hyperactivity, and impulsivity across the life cycle and is associated with considerable morbidity and disability. Comorbidity is a distinct clinical feature of both childhood and adult ADHD. Although its etiology remains unclear, emerging evidence documents its strong neurobiologic and genetic underpinnings. Despite the high diagnostic reliability and the robust evidence of the validity of ADHD, there are many underlying issues that remain to be resolved. These include establishing developmentally appropriate diagnostic criteria at older ages, further elaborating the impact of gender on symptom expression, and examining risk and protective factors in relationship to prevention or amelioration of ADHD as well as related functional impairments.
Sodium Bismuthate Mediated Oxidation of Allylic and Benzylic Alcohols

Abstract A simple and readily available oxidation of primary allylic and benzylic alcohols to the corresponding aldehydes is carried out by sodium bismuthate in acetic acid.
Th(VO3)2(SeO3) and Ln(VO3)2(IO3) (Ln = Ce, Pr, Nd, Sm, and Eu): unusual cases of aliovalent substitution

Th(VO3)2(SeO3) and Ln(VO3)2(IO3) (Ln = Ce, Pr, Nd, Sm, and Eu) have been prepared and characterized. Surprisingly, these compounds are isotypic and rather extreme examples of aliovalent substitution (ThIVvs. LnIII; SeIVO32−vs. IVO3−) are possible in this structure type.
A comparison of two types of social support for mothers of mentally ill children.

In the United States, approximately 20% of children have mental health problems, of which only 20% are receiving mental health services (National Institute of Mental Health, 2002; U.S. Public Health Service, 2000) and only about half are receiving appropriate services (Junek & Thompson, 1999; Knitzer, 1993; President’s New Freedom Commission on Mental Health, 2003). As with other areas of health care, more and more responsibility for mental health care is being placed on the parents or other primary caregivers (Grey, Knafl, & McCorkle, 2006). Being the mother of a child with mental illness is associated with high levels of distress and depression (Elgar, McGrath, Waschbusch, Stewart, & Curtis, 2004). Efforts to reduce parents’ depression and/or distress have been significantly associated with improvement in child mental health problems (Weissman et al., 2006). However, the main focus of care is typically the treatment of the child, and as a result, the parents’ needs are rarely addressed (Downey & Coyne, 1990; Elgar et al.). According to the National Mental Health Association and the Federation of Families for Children’s Mental Health (NMHA & FOF, 1993), parents who are caring for children with mental illness find it extremely difficult to get their own mental health needs met while trying to meet the mental health needs of their children. The Surgeon General’s Conference on Children’s Mental Health (U.S. Public Health Service) noted that these children and their families face a healthcare crisis because of a lack of available services. A randomized controlled investigation is being conducted to test two types of social support interventions—TSS and Web-based social support—for mothers of seriously mentally ill children. Mothers recruited for the study have children ranging from 5 to 12 years of age who have been recently discharged from an inpatient psychiatry unit. The ongoing study uses an experimental design with randomization to three groups: a usual care group, a TSS group, and a Web-based social support group. This paper reports the findings from a qualitative portion of the investigation examining the interactions between mothers with the TSS nurses and the chat room nurse facilitator. The purpose of this analysis was to compare the amount and types of support offered via these two different types of telehealth interventions.
Do Tax Cuts Starve the Beast?: The Effect of Tax Changes on Government Spending

The hypothesis that decreases in taxes reduce future government spending is often cited as a reason for cutting taxes. However, because taxes change for many reasons, examinations of the relationship between overall measures of taxation and subsequent spending are plagued by problems of reverse causation and omitted variable bias. To derive more reliable estimates, this paper examines the behavior of government expenditure following legislated tax changes that narrative sources suggest are largely uncorrelated with other factors affecting spending. The results provide no support for the hypothesis that tax cuts restrain government spending; indeed, the point estimates suggest that tax cuts increase spending. The results also indicate that the main effect of tax cuts on the government budget is to induce subsequent legislated tax increases. Examination of four episodes of major tax cuts reinforces these conclusions.
Uncertainty Shocks, Asset Supply and Pricing over the Business Cycle

This article estimates a business cycle model with endogenous financial asset supply and ambiguity averse investors. Firms’ shareholders choose not only production and investment, but also capital structure and payout policy subject to financial frictions. An increase in uncertainty about profits lowers stock prices and leads firms to substitute away from debt as well as reduce shareholder payout. This mechanism parsimoniously accounts for the postwar comovement in investment, stock prices, leverage, and payout, at both business cycle and medium term cycle frequencies. Ambiguity aversion permits a Markov-switching VAR representation of the model, while preserving the effect of uncertainty shocks on the time variation in the equity premium.
Analytic and simulation methods in computer network design

The Seventies are here and so are computer networks! The time sharing industry dominated the Sixties and it appears that computer networks will play a similar role in the Seventies. The need has now arisen for many of these time-shared systems to share each others' resources by coupling them together over a communication network thereby creating a computer network. The mini-computer will serve an important role here as the sophisticated terminal as well as, perhaps, the message switching computer in our networks.
A critical review of accounting and economic methods for estimating the costs of addiction treatment

Researchers have been at the forefront of applying new costing methods to drug abuse treatment programs and innovations. The motivation for such work has been to improve costing accuracy. Recent work has seen applications initiated in establishing charts of account and cost accounting for service delivery. As a result, researchers now have available five methods to apply to the costing of drug abuse treatment programs. In all areas of costing, there is room for more research on costing concepts and measurement applications. Additional work would be useful in establishing studies with activity-based costing for both research and managerial purposes. Studies of economies of scope are particularly relevant because of the integration of social services and criminal justice in drug abuse treatment. In the long run, managerial initiatives to improve the administration and quality of drug abuse treatment will benefit directly from research with new information on costing techniques.
Patterns of rainfall insurance participation in rural India

Take-up of an innovative rainfall insurance policy offered to smallholder farmers in rural India decreases with basis risk between insurance payouts and income fluctuations, increases with household wealth, and decreases with binding credit constraints. These results are consistent with the predictions of a simple neoclassical model with borrowing constraints. Other patterns are less consistent with the benchmark model. For example, participation in village networks and measures of familiarity with the insurance vendor are strongly correlated with insurance take-up decisions, and risk-averse households are less, not more, likely to purchase insurance. These results may reflect household uncertainty about the product, given their limited experience with it.
Probability 1 computation with chemical reaction networks

The computational power of stochastic chemical reaction networks (CRNs) varies significantly with the output convention and whether or not error is permitted. Focusing on probability 1 computation, we demonstrate a striking difference between stable computation that converges to a state where the output cannot change, and the notion of limit-stable computation where the output eventually stops changing with probability 1. While stable computation is known to be restricted to semilinear predicates (essentially piecewise linear), we show that limit-stable computation encompasses the set of predicates $$\phi :{\mathbb {N}}\rightarrow \{0,1\}$$?:N?{0,1} in $$\Delta ^0_2$$Δ20 in the arithmetical hierarchy (a superset of Turing-computable). In finite time, our construction achieves an error-correction scheme for Turing universal computation. We show an analogous characterization of the functions $$f:{\mathbb {N}}\rightarrow {\mathbb {N}}$$f:N?N computable by CRNs with probability 1, which encode their output into the count of a certain species. This work refines our understanding of the tradeoffs between error and computational power in CRNs.
The welfare effects of third-degree price discrimination in intermediate good markets: the case of bargaining

This article examines the welfare effects of third-degree price discrimination by a monopolist selling to downstream firms with bargaining power. One of the downstream firms (the �chain store�) can integrate backward at lower cost than rivals. Bargaining powers also depend on disagreement profits, bargaining weights, and concession costs. If the chain's integration threat is not credible, price discrimination reduces the input price charged symmetric downstream firms and often reduces the average input price charged asymmetric downstream firms.
Throughput guarantees for multi-priority traffic in ad hoc networks

In this paper, we present MPARC (Multi-Priority Admission and Rate Control), a novel joint admission control and rate policing protocol for multi-priority ad hoc networks. MPARC is based on our novel bandwidth allocation model, which captures the bandwidth allocation for saturated, unsaturated and semi-saturated networks. MPARC guarantees that the throughput of admitted realtime flows will not decrease due to later arriving realtime flows with equal or lower priorities or due to best effort flows. MPARC achieves this goal by performing accurate admission control on every newly arriving realtime flow and appropriate rate policing on all best effort traffic. Through simulation, we demonstrate that MPARC has better performance than existing approaches.
Social preferences, self-interest, and the demand for redistribution

Preferences for redistribution may be influenced by values and beliefs about distributive justice as well as by self-interest. People may prefer more redistribution to the poor if they believe that poverty is caused by circumstances beyond individual control. Therefore, beliefs about the causes of income may affect demand for redistribution. Alternatively, the effect of these beliefs on redistributive preferences may be spurious if they are correlated with income, and self-interest is not properly controlled for. They may also measure incentive cost concerns. Using social survey data, I find that self-interest cannot explain the effect of these beliefs on redistributive preferences. © 2001 Elsevier Science B.V. All rights reserved.
Enantioselective synthesis of All 2,4-dideoxyhexose stereoisomers

The preparation of all possible methyl 2,4-dideoxyhexopyranosides starting from optically pure enzymatic asymmetrization products1 and 2 is reported.
The Near-Infrared Background: Interplanetary Dust or Primordial Stars?

The intensity of the diffuse ~1-4 μm sky emission from which solar system and Galactic foregrounds have been subtracted is in excess of that expected from energy released by galaxies and stars that formed during the z 5 redshift interval.The spectral signature of this excess near-infrared background light (NIRBL) component is almost identical to that of reflected sunlight from the interplanetary dust cloud and could therefore be the result of the incomplete subtraction of this foreground emission component from the diffuse sky maps. Alternatively, this emission component could be extragalactic. Its spectral signature is consistent with that of redshifted continuum and recombination line emission from H II regions formed by the first generation of very massive stars. In this paper we analyze the implications of this spectral component for the formation rate of these Population III stars, the redshift interval during which they formed, the reionization of the universe, and evolution of collapsed halo masses. Assuming that these Population III stars are massive objects radiating at the Eddington luminosity and ending their lives by directly collapsing into black holes, we find that to reproduce the intensity and spectral shape of the NIRBL requires a peak star formation rate of ~2.5 M☉ yr-1 Mpc-3, with a (1 + z)-2 dependence on redshift, until the epoch ends at redshifts z ≈ 7-9. It requires a comoving luminosity density of about 2.7 × 1011 L☉ Mpc-3, corresponding to a total energy input of 670-820 keV per baryon, and that about 10% of the total number of baryons in the universe be converted to Population III stars. All these numbers are higher by about a factor of 4-10 than those derived from models in which Population III stars form at a rate that is proportional to the collapse rate of halos in a cold dark matter dominated universe. Furthermore, an extragalactic origin for the NIRBL leads to physically unrealistic absorption-corrected spectra of distant TeV blazars. All these results suggest that Population III stars contribute only a fraction of the NIRBL intensity, with zodiacal light, star-forming galaxies, and/or nonnuclear sources giving rise to the remaining fraction. Further 0.1-10 μm observations of the diffuse sky and the zodiacal cloud are therefore crucial for resolving the true spectrum and origin of the NIRBL.
Description and tracking of moving articulated objects

This paper discusses the problem of deriving a description for an articulated object from images taken in the real environment. Sometimes with the articulated object, the detection of the articulation is difficult depending on the deformation or the direction of the view line. Also, the false articulation is detected due to the disconnection of the object contour derived from the image or due to the noise. To cope with such difficulties, a method is proposed for the moving articulated object, where the articulation is detected with a high reliability, and the description as well as the segmentation of the articulated object are derived by processing a series of images containing different outblocks and deformations of the object. In this method, the ribbon, which is the two-dimensional version of the generalized cylinder, is used as the basic representation for the part. The initial description is derived from each frame image, and the initial descriptions of various frames are compared by ribbon matching to detect the articulation position with a high reliability. Based on the detected positions, the initial descriptions are integrated selectively and the final description is obtained. As a by-product of the ribbon matching, the tracking of parts also is realized. By an experiment using a human walking scene, the usefulness of the proposed method is demonstrated.
Dynamics on Berkovich Spaces in Low Dimensions

These are expanded lecture notes for the summer school on Berkovich spaces that took place at the Institut de Mathematiques de Jussieu, Paris, during June 28–July 9, 2010. They serve to illustrate some techniques and results from the dynamics on low-dimensional Berkovich spaces and to exhibit the structure of these spaces.
Application of Comparative Dynamics in Stochastic Invasive Species Management in Agricultural Production

In this study, we formulate a stochastic dynamic framework for pest control over the growing season taking into account forecasts of weather conditions and pest infestation expectations. Using stochastic envelope theorem and stochastic comparative dynamics, we analytically show how the stochastic correlation between the prediction errors should affect optimal pesticide usage path. As a case study, we apply the analytical results of the paper for pesticide use in the Palouse region of Washington where pea aphid is the primary threat for lentil production. By stochastic dynamic programming, our simulation shows the optimal dimethoate usage path, which illustrates our findings in the analytical part.
Combining Forecasts from Nested Models

Motivated by the common finding that linear autoregressive models forecast better than models that incorporate additional information, this paper presents analytical, Monte Carlo, and empirical evidence on the e!e ctiveness of combining forecasts from nested models. In our analytics, the unrestricted model is true, but as the sample size grows, the data generating process converges to the restricted model. This approach captures the practical reality that the predictive content of variables of interest is often low. We derive MSE-minimizing weights for combining the restricted and unrestricted forecasts. Monte Carlo and empirical analyses verify the practical e!e ctiveness of our combination approach.
Drinking Water Salinity and Infant Mortality in Coastal Bangladesh

Bangladesh, with two-thirds of its land area less than five meters above sea level, is one of the most climate-vulnerable countries in the world. Low-lying coastal districts along the Bay of Bengal are particularly vulnerable to sea level rise, tidal flooding, storm surges, and climate-induced increases in soil and water salinity. This paper investigates the impact of drinking water salinity on infant mortality in coastal Bangladesh. It focuses on the salinity of drinking water consumed during pregnancy, which extensive medical research has linked to maternal hypertension, preeclampsia, and post-partum morbidity and mortality. The study combines spatially-formatted salinity measures for 2001-09 provided by Bangladesh with individual and household survey information from the Bangladesh Demographic and Health Surveys for 2004 and 2007. It uses probit and logit analyses to estimate mortality probability for infants less than two months old. Controlling for many other determinants of infant mortality, the analysis finds high significance for salinity exposure during the last month of pregnancy and no significance for exposure during the preceding months. The estimated impact of salinity on infant mortality is comparable in magnitude to the estimated effects of traditionally-cited variables such as maternal age and education, gender of the household head, household wealth, toilet facilities, drinking water sources, and cooking fuels.
Continued fractions and heavy sequences

We initiate the study of the sets H(c), 0 c). More formally, H(c) def {α∈ℝ | card ({1≤k≤ n | (kα) cn, for all n > 1}, where (x) = x ― [x] stands for the fractional part of x ∈ R. We prove that, for rational c, the sets H(c) are of positive Hausdorff dimension and, in particular, are uncountable. For integers m > 1, we obtain a surprising characterization of the numbers α ∈ H m = def H(1/m) in terms of their continued fraction expansions: The odd entries (partial quotients) of these expansions are divisible by m. The characterization implies that x ∈ H m if and only if 1/mx ∈ H m , for x > 0. We are unaware of a direct proof of this equivalence without making use of the mentioned characterization of the sets H m . We also introduce the dual sets H m of reals y for which the sequence of integers ([ky]) k≥1 consistently hits the set mZ with the at least expected frequency 1/m and establish the connection with the sets H m : If xy = m for x, y > 0, then x ∈ Hm ⇒ y ∈ H m . The motivation for the present study comes from Y. Peres's ergodic lemma.
Understanding Friction Factor Behavior in Liquid Annular Seals With Deliberately Roughened Surfaces

Multistage centrifugal pumps and compressors are among the most widely used pieces of rotating machinery in industry. A typical application demands the arrangement of several impellers or wheels mounted on a shaft that spins within a stationary case. Annular seals are the most common sealing devices used in this type of machinery. The annular seal design affects both (i) machinery performance in terms of energy conversion efficiency, and (ii) stability due to the interaction within the rotor and the stator through the fluid flow within the seals. Traditionally, the “bulk-flow” theory due to Hirs 1 has been used to estimate annular seals leakage and dynamic coefficients. To predict the flow behavior through the seal, this theory relies on empirical friction factor correlations. While leakage is well predicted, the dynamic coefficients are not. The discrepancy is attributed to the friction factor model. Several experiments have produced seal leakage data indicating that friction factor increases as the seal clearance is increased, contradicting predictions based on Moody’s pipe-friction model. A Computational Fluid Dynamics (CFD) commercial code was used to simulate flat-platechannel-flow experimental tests of water flowing within deliberately roughened surfaces, showing a directly proportional behavior of the friction factor versus the plate clearance. The higher friction factor characteristics of these deliberately roughened surfaces are governed by their ability to develop a high static pressure in the trailing face of each roughness cavity, while the wall shear stresses on the smooth land play a secondary role. In a certain Reynolds number range, the maximum friction factor observed in a specific roughness pattern size is independent of the actual clearance, in what we have referred to as the friction-factor-to-clearance indifference behavior. This phenomenon appears to be related to the roughness cavity size and its length-to-clearance ratio. NOMENCLATURE
A photonic analog-to-digital converter based on an unbalanced Mach-Zehnder quantizer

A Mach-Zehnder modulator (MZM) based analog to digital converter (ADC) is described. The signal to be digitized is applied to a single electrode of a high speed unbalanced modulator that acts as a quantizer. The rest of the system consists of commercially available wavelength division multiplexing (WDM) components. Analysis indicates that 6 bit operation at 40 Giga Samples per second (GS/s) is possible with moderate optical carrier power.
Vascular endothelium, hemodynamic forces, and atherogenesis.

Intimal lipid accumulation, hyperplasia, and scarring are stigmata of atherosclerotic vascular disease, whose major complications—myocardial and cerebral ischemia and infarction—continue to be major health problems in developed nations. 1 This insidiously progressive disease typically spans decades, but can reach a clinical horizon in a matter of minutes due to critical changes in a given atherosclerotic plaque that result in localized but life-threatening thrombosis. Epidemiological studies have established that hypercholesterolemia is an important risk factor in this disease process, and lipid-lowering drugs have been proven to have clinical efficacy. Experimental animals that are fed lipid-rich diets to elevate their plasma cholesterol levels also can develop atherosclerotic-like lesions, as do animals with naturally occurring or genetically engineered mutations that result in altered cholesterol metabolism. However, regardless of a given patient’s risk factor profile, species of animal model, or type of natural or engineered genetic alteration, the early, lipid-rich lesions of atherosclerosis show a markedly nonrandom pattern of distribution within the arterial vasculature. Atherosclerotic lesions typically develop in the vicinity of branch points and areas of major curvature. These arterial geometries are associated with blood flow disturbances such as nonuniform laminar flow with boundary layer separation, complex secondary flows with flow reversal and dynamic stagnation points, and resultant temporal and spatial gradients in wall shear stresses. In contrast to these atherosclerosis-prone areas, unbranched, tubular arterial geometries, which are associated with a more uniformly laminar flow profile, characteristically are relatively atherosclerosis-resistant, at least in the early phases of the disease. This strikingly localized pattern of lesion formation, even in the face of systemic risk factors such as elevated plasma cholesterol, has intrigued experimental pathologists and fluid mechanical engineers alike for decades, and has motivated the search for a mechanistic link between hemodynamic forces and atherogenesis.
Downlink dynamic resource allocation for multi-cell OFDMA system

This paper presents an OFDMA radio resource control (RRC) scheme where dynamic resource allocation is realized at both a radio network controller (RNC) and base stations (BTSs). The scheme is semi-distributed in the sense that the RNC coordinates the mutual interference (inter-cell) at a super-frame level, whereas each BTS makes faster frame-level channel assignment decision based on resources' utility value to users. Another contribution of the paper is a set of computationally efficient algorithms that perform dynamic channel allocation at RNC and BTSs. Simulations show that the algorithm yields excellent performance for both real-time and non real-time services, even under very fast fading.
Mass production technology for multicrystalline Si solar cells

Worldwide shipments of PV modules in the last 10 years show an increase of about 20% per year; shipments were 277 MW in 2000. About 80% of modules are made from crystalline silicon. Shipments of multicrystalline silicon (mc-Si) modules have shown substantial increase. The PV market may be expected to increase by the development of low-cost, and high-technology multicrystalline silicon solar cells. This paper reviews recent progress in mass production technologies of mc-Si solar cells. Copyright © 2002 John Wiley & Sons, Ltd.
Communicating Vague Spatial Concepts in Human-GIS Interactions: A Collaborative Dialogue Approach

Natural language requests involving vague spatial concepts are not easily communicated to a GIS because the meaning of spatial concepts depends largely on the contexts (such as task, spatial contexts, and user’s personal background) that may or may not be available or specified in the system. To address such problems, we developed a collaborative dialogue approach that enables the system and the user to construct shared knowledge about relevant contexts. The system is able to anticipate what contextual knowledge must be shared, and to form a plan to exchange contextual information based on the system’s belief on who knows what. To account those user contexts that are not easily communicated by language, direct feedback approach is used to refine the system’s belief so that the intended meaning is properly grounded. The approach is implemented as a dialogue agent, GeoDialogue, and is illustrated through an example dialogue involving the communication of the vague spatial concept near.
A simple model of unbounded evolutionary versatility as a largest-scale trend in organismal evolution

The idea that there are any large-scale trends in the evolution of biological organisms is highly controversial. It is commonly believed, for example, that there is a large-scale trend in evolution towards increasing complexity, but empirical and theoretical arguments undermine this belief. Natural selection results in organisms that are well adapted to their local environments, but it is not clear how local adaptation can produce a global trend. In this paper, I present a simple computational model, in which local adaptation to a randomly changing environment results in a global trend towards increasing evolutionary versatility. In this model, for evolutionary versatility to increase without bound, the environment must be highly dynamic. The model also shows that unbounded evolutionary versatility implies an accelerating evolutionary pace. I believe that unbounded increase in evolutionary versatility is a large-scale trend in evolution. I discuss some of the testable predictions about organismal evolution that are suggested by the model.
Hydrogen-Mediated C−C Bond Formation: Catalytic Regio- and Stereoselective Reductive Condensation of α-Keto Aldehydes and 1,3-Enynes

Hydrogenation of 1,3-enynes in the presence of alpha-keto aldehydes using cationic Rh(I) catalysts enables regio- and stereoselective reductive coupling to the acetylenic terminus of the enyne to afford (E)-2-hydroxy-3,5-dien-1-one products. Reductive condensation of 1-phenyl but-3-en-1-yne 1a with phenyl glyoxal 2a performed under an atmosphere of D(2) provides the product of mono-deuteration, (E)-2-hydroxy-3-deuterio-3,5-dien-1-one deuterio-3a, in 85% yield. Competition experiments involving catalytic hydrogenation of phenyl glyoxal in the presence of equimolar quantities of 1,4-diphenylbutadiene and 1,4-diphenylbut-3-en-1-yne 10a, as well as 1,4-diphenylbut-3-en-1-yne 10a and 1,4-diphenylbutadiyne, are chemoselective for coupling to the more highly unsaturated partner, suggesting a preequilibrium involving precoordination and exchange of the pi-unsaturated pronucleophiles with the catalyst prior to C-C bond formation, as well as a preference for coordination of the most pi-acidic reacting partner, as explained by the Dewar-Chatt-Duncanson model for alkyne coordination.
DYNAMIC ASPECTS OF FAMILY TRANSFERS

Parents transfer a great deal to their adult children, and we have rich theoretical models providing a framework for these transfers. However, both the models and existing empirical work typically examine behavior in the cross section. To date, we know little about the dynamic aspects of family transfers. Here I examine transfers over a span of 17 years and find substantial changes in recipiency over time and a strong negative correlation between transfers and transitory income. I also find that events such as job loss and divorce are strong predictors of parental transfers and, although rare, are typically associated with larger transfers than income alone might predict. Finally, transfers are distributed unequally across siblings, and perhaps surprisingly, the distribution of transfers becomes even more unequal when examined over an extended period of time than in any single year. The evidence presented here thus suggests that dynamic analyses can provide insights into behavior that are impossible to obtain in a static context.
Interconnection and electromigration scaling theory

Interconnections will become the limit in performance and reliability at submicrometer dimensions. Long-distance interconnections are defined using models based on resistivity, and it is found that more than half of the interconnections will become categorized as such at 0.5-µm feature sizes. The resistivity of even less resistive materials, therefore, will become important. A model for analyzing the trends of material usage for interconnections and for projecting design rules is presented. Electromigration is the driving force away from the lowest resistivity silicon compatible material, namely aluminum. Replacements such as gold, however, have technological problems and the resistivity of refractory metals will be too high for a large fraction of the interconnections. Layered structures are one possible solution to the problems of electromigration and hillocks.
Industry concentration in common value auctions: theory and evidence

We examine theoretically and experimentally two countervailing effects of industry concentration in common value auctions. Greater concentration of information among fewer bidders reduces competition but increases the precision of private estimates. We demonstrate that this generally leads to more aggressive bidding. However, the reduction in competition dominates the informational effects, resulting in lower prices. We examine these hypothesized effects experimentally by conducting a series of auctions with constant informational content but distributed among a varying number of bidders. The experimental results are consistent with our theoretical predictions.
Semiconductor Device Scaling: Physics, Transport, and the Role of Nanowires

Nanoelectronics (including nanomagnetics and nanophotonics) generally refer to nanometer scale devices, and to circuits and architectures which are composed of these devices. Continued device scaling into the nanometer range leads to enhanced information processing systems. Generally, this scaling has arisen from three major sources, one of which is reduction of the physical gate length of individual transistors. Until recently, this has also allowed an increase in the clock speed of the chip, but power considerations have halted this to levels around 4 GHz in Si. Indeed, there are indications that scaling itself may be finished by the end of this decade. Instead, there are now pushes to seek alternative materials for nano-devices that may supplement the Si CMOS in a manner that allows both higher speeds and lower power. This paper covers some of the impending limitations, and discuss some alternative approaches that may signal continued evolution of integrated circuits beyond the end of the decade.
An analytical dishing and step height reduction model for chemical mechanical planarization (CMP)

An analytical model for dishing and step height reduction in chemical mechanical planarization (CMP) is presented. The model is based on the assumption that at the feature scale, high areas on the wafer experience higher pressure than low areas. A Prestonian material removal model is assumed. The model delineates how dishing and step height reduction depend on slurry properties (selectivity and Preston's constants), pad characteristics (stiffness and bending ability), polishing conditions (pressure, relative velocity and overpolishing) and wafer surface geometry (linewidth, pitch and pattern density). Model predictions are in good agreement with existing experimental observations. The present model facilitates understanding of the CMP process at the feature scale. Based on the proposed model, design avenues for decreasing dishing and increasing the speed of step height reduction may be explored through modification of appropriate parameters for slurry, pad and polishing conditions. The proposed model may also be used as a design tool for pattern layout to optimize the performance of the CMP process.