cssi/SciSciGPT-SciSciNet huggingface dataset:
Local and sex-specific biases in crossover vs. noncrossover outcomes at meiotic recombination hot spots in mice

Meiotic recombination initiated by programmed double-strand breaks (DSBs) yields two types of interhomolog recombination products, crossovers and noncrossovers, but what determines whether a DSB will yield a crossover or noncrossover is not understood. In this study, we analyzed the influence of sex and chromosomal location on mammalian recombination outcomes by constructing fine-scale recombination maps in both males and females at two mouse hot spots located in different regions of the same chromosome. These include the most comprehensive maps of recombination hot spots in oocytes to date. One hot spot, located centrally on chromosome 1, behaved similarly in male and female meiosis: Crossovers and noncrossovers formed at comparable levels and ratios in both sexes. In contrast, at a distal hot spot, crossovers were recovered only in males even though noncrossovers were obtained at similar frequencies in both sexes. These findings reveal an example of extreme sex-specific bias in recombination outcome. We further found that estimates of relative DSB levels are surprisingly poor predictors of relative crossover frequencies between hot spots in males. Our results demonstrate that the outcome of mammalian meiotic recombination can be biased, that this bias can vary depending on location and cellular context, and that DSB frequency is not the only determinant of crossover frequency.
The influence of enhanced surface magnetism on finite-size scaling

The thickness-dependent spin-polarized electronic structure of strained ultrathin and thin films of Gd has been investigated. The surface magnetic structure dominates the magnetic ordering of the ultrathin Gd films. With decreasing thickness some bulk bands exhibit increasingly more "passive" magnetic behavior. These bulk bands resemble a paramagnet over an increasing volume of the bulk Brillouin zone with decreasing film thickness.
Sampling independent sets in the discrete torus

The even discrete torus is the graph TL,d on vertex set {0,…,L 1}d (with L even) in which two vertices are adjacent if they differ on exactly one coordinate and differ by 1(modL) on that coordinate. The hard-core measure with activity λ on TL,d is the probability distribution πλ on the independent sets (sets of vertices spanning no edges) of TL,d in which an independent set I is chosen with probability proportional to λ|I|. This distribution occurs naturally in problems from statistical physics and the study of communication networks. We study Glauber dynamics, a single-site update Markov chain on the set of independent sets of TL,d whose stationary distribution is πλ. We show that for λ = ω(d-1-4 log 3-4d) and d sufficiently large the convergence to stationarity is (essentially) exponentially slow in Ld-1. This improves a result of Borgs, Chayes, Frieze, Kim, Tetali, Vigoda, and Vu (Proceedings of the IEEE FOCS (1999), 218229) [5] who had shown slow mixing of Glauber dynamics for λ growing exponentially with d. Our proof, which extends to ρ-local chains (chains which alter the state of at most a proportion ρ of the vertices in each step) for suitable ρ, closely follows the conductance argument of Borgs et al., [5] adding to it some combinatorial enumeration methods that are modifications of those used by Galvin and Kahn (Combinatorics, Probability and Computing 13 (2004), 137164) [12] to show that the hard-core model with parameter λ on the integer lattice ℤd exhibits phase coexistence for λ = ω(d-1-4 log 3-4d). The discrete even torus is a bipartite graph, with partition classes µ (consisting of those vertices the sum of whose coordinates is even) and $$ \cal{O} $$. Our result can be expressed combinatorially as the statement that for each sufficiently large λ, there is a ρ(λ) > 0 such that if I is an independent set chosen according to πλ, then the probability that ‖I ∩e||I ∩$ \cal{O} $‖ is at most ρ(λ)Ld is exponentially small in Ld-1. In particular, we obtain the combinatorial result that for all e > 0 the probability that a uniformly chosen independent set from TL,d satisfies ‖I ∩e||I ∩$ \cal{O} $‖≤ (.25 - e)Ld is exponentially small in Ld-1. © 2008 Wiley Periodicals, Inc. Random Struct. Alg., 2008 Author supported by National Science Foundation (DMS-0111298) while a member of Institute for Advanced Study.
Learning in parallel

Abstract In this paper, we extend Valiant's (Comm. ACM27 (1984), 1134–1142) sequential model of concept learning from examples and introduce models for the efficient learning of concept classes from examples in parallel. We say that a concept class is NC -learnable if it can be learned in polylog time with a polynomial number of processors. We show that several concept classes which are polynomial-time learnable are NC -learnable in constant time. Some other classes can be shown to be NC -learnable in logarithmic time, but not in constant time. Our main result shows that other classes, such as s-fold unions of geometrical objects in Euclidean space, which are polynomial-time learnable by a greedy set cover technique, are NC -learnable using a nongreedy technique. We also show that (unless P ⊆ RNC ) several polynomial-time learnable concept classes related to linear programming are not NC -learnable. Equivalence of various parallel learning models and issues of fault-tolerance are also discussed.
The Aggregate Effects of Trade and Migration: Evidence from OECD Countries

Two large but separate bodies of literature analyze the economic effects of international trade and immigration. Given that several factors affect both trade and migration flows, the previous studies potentially suffer from omitted-variables bias. This paper provides estimates of the effects of trade and immigration on income in a unified framework. We also provide a useful decomposition of the channels at work. We assemble panel data on immigration flows, output, employment and capital stocks for 30 OECD countries over the period 1980–2007. In order to identify the causal effects of trade and immigration we extend the gravity-based approach in Frankel and Romer (Am Econ Rev 89(3):379–399, 1999). Our predictors for trade and immigration flows are based on geography and the demographic trends of each country’s trade and migration partners. Our estimates suggest that immigration and trade do not have a significant effect on income per capita in the short run. However, this masks offsetting effects. Trade openness appears to reduce capital intensity but increase TFP. This is consistent with an increase in the degree of specialization in knowledge-intensive industries for OECD countries. In the case of immigration we find that it leads to an increase in the employment rate of the receiving economy but, at the same time, it appears to reduce TFP.
Partisan Mobilization Using Volunteer Phone Banks and Door Hangers

This article presents the results from a statewide partisan voter mobilization experiment in Michigan during the 2002 gubernatorial election. The tactics studied are volunteer phone calls and door hangers. With regard to turnout, the conclusion reached is that volunteer phone calls boost turnout by 3.2 percentage points and door hangers boost turnout by 1.2 percentage points. This effect size implies that both mobilization technologies are cost-competitive with door knocking and that partisan and nonpartisan campaigns are equally effective at increasing turnout. A postelection survey was used to determine whether the partisan blandishments to vote changed candidate preference. No evidence of persuasion from campaign contact was detected by the survey. However, the survey did indicate that the campaign failed in targeting likely Democratic voters and excluding likely Republican voters, emphasizing the need for detailed party databases.
The growth aftermath of natural disasters

This paper provides a description of the macroeconomic aftermath of natural disasters. It traces the yearly response of gross domestic product growth - both aggregated and disaggregated into its agricultural and non-agricultural components - to four types of natural disasters - droughts, floods, earthquakes, and storms. The paper uses a methodological approach based on pooling the experiences of various countries over time. It consists of vector auto-regressions in the presence of endogenous variables and exogenous shocks (VARX), applied to a panel of cross-country and time-series data. The analysis finds heterogeneous effects on a variety of dimensions. First, the effects of natural disasters are stronger, for better or worse, on developing than on rich countries. Second, while the impact of some natural disasters can be beneficial when they are of moderate intensity, severe disasters never have positive effects. Third, not all natural disasters are alike in terms of the growth response they induce, and, perhaps surprisingly, some can entail benefits regarding economic growth. Thus, droughts have a negative effect on both agricultural and non-agricultural growth. In contrast, floods tend to have a positive effect on economic growth in both major sectors. Earthquakes have a negative effect on agricultural growth but a positive one on non-agricultural growth. Storms tend to have a negative effect on gross domestic product growth but the effect is short-lived and small. Future research should concentrate on exploring the mechanisms behind these heterogeneous impacts.
Understanding the impact of trails on residential property values in the presence of spatial dependence

This paper examines the impacts of a multi-purpose trail on residential property values in a hedonic model. Using a large housing data set in combination with street network distances, we show that proximity to trail entrances positively effects property values. Among other things, our study compares the hedonic model results from three different spatial specifications. We pay specific attention to the direct and indirect effects on residential property prices associated with potential changes in house characteristics. In addition, our study predicts property values around trail entrances using a ‘modified spatial predictive process’ approach that is well suited for capturing spatial dependence in large data sets.
Underfunding in Terrorist Organizations

A review of international terrorist activity reveals a pattern of financially strapped operatives working for organizations that seem to have plenty of money. To explain this observation, and to examine when restricting terrorists' funds will reduce their lethality, we model a hierarchical terror organization in which leaders delegate financial and logistical tasks to middlemen, but cannot perfectly monitor them for security reasons. These middlemen do not always share their leaders' interests: the temptation exists to skim funds from financial transactions. When middlemen are sufficiently greedy and organizations suffer from sufficiently strong budget constraints, leaders will not fund attacks because the costs of skimming are too great. Using general functional forms, we find important nonlinearities in terrorists' responses to government counter-terrorism. Restricting terrorists' funds may be ineffective until a critical threshold is reached, at which point cooperation within terrorist organizations begins to break down and further government actions have a disproportionately large impact.
On the Evolutionary Status of Class I Stars and Herbig-Haro Energy Sources in Taurus-Auriga

We present high-resolution (R ~ 34,000) optical (6330-8750 A) spectra obtained with the HIRES spectrograph on the W. M. Keck I telescope of stars in Taurus-Auriga whose circumstellar environment suggests that they are less evolved than optically revealed T Tauri stars. Many of the stars are seen only via scattered light. The sample includes 15 class I stars and all class II stars that power Herbig-Haro flows in this region. For 28 of the 36 stars observed, our measurements are the first high-dispersion optical spectra ever obtained. Photospheric features are observed in all stars with detected continuum, 11 of 15 class I stars (42% of known Taurus class I stars) and 21 of 21 class II stars; strong emission lines (e.g., Hα) are detected in the spectra of all stars. These spectra, in combination with previous measurements, are used to search for differences between stars that power Herbig-Haro flows and stars that do not and to reassess the evolutionary state of so-called protostars (class I stars) relative to optically revealed T Tauri stars (class II stars). The stellar mass distribution of class I stars is similar to that of class II stars and includes three spectroscopically confirmed class I brown dwarfs. Class I stars (and brown dwarfs) in Taurus are slowly rotating (v sin i < 35 km s^(-1)); the angular momentum of a young star appears to dissipate prior to the optically revealed T Tauri phase. The amount of optical veiling and the inferred mass accretion rates of class I stars are surprisingly indistinguishable from class II stars. Class I stars do not have accretion-dominated luminosities; the accretion luminosity accounts for ~25% of the bolometric luminosity. The median mass accretion rate of class I and class II stars of K7-M1 spectral type is 4 × 10^(-8) M_☉ yr^(-1), and the median mass outflow rate is 5% of the mass accretion rate. The large ranges in mass accretion rate (~2 orders of magnitude), mass outflow rate (~3 orders of magnitude), and the ratio of these quantities (~2 orders of magnitude) represent real dispersions in young accreting stars of similar mass. We confirm previous results that find larger forbidden-line emission associated with class I stars than class II stars. We suggest that this is caused by an orientation bias that allows a more direct view of the somewhat extended forbidden emission line regions than of the obscured stellar photospheres, rather than being caused by larger mass outflow rates. Overall, the similar masses, luminosities, rotation rates, mass accretion rates, mass outflow rates, and millimeter flux densities of class I stars and class II stars are best explained by a scenario in which most class I stars are no longer in the main accretion phase and are much older than traditionally assumed. Similarly, although stars that power Herbig-Haro flows appear to have larger mass outflow rates, their stellar and circumstellar properties are generally indistinguishable from those of similar mass stars that do not power these flows.
Capillary rheology of two composite resin systems

The rheological properties of two commercial resin systems, Isopast and Cosmic, were studied in the shear rate range 0.65-65 s-1 by capillary techniques. Isopast represents a low inorganic filled composite, whereas Cosmic is a conventionally filled system whose resin matrix resembles that of Isopast. All components of both systems obeyed power law dependence of shear stress as a function of shear rate according to the relation 1n tau = 1n K + n 1n gamma; values of n for Cosmic catalyst and paste and Isopast paste were of the order of 0.6 whereas Isopast catalyst was of the order of 0.3. Setting systems obeyed a power law relationship during the working time with an exponent n congruent to 0.7-1.0. Accordingly the systems appear pseudoplastic in component form and slightly pseudoplastic to near Newtonian after mixing.
Demography and Low-Frequency Capital Flows

Abstract We consider the role of demographic trends in driving international capital flows in a multicountry overlapping generations model in which saving decisions are tied to agents' life expectancy. Capital flows reflect differences between saving and investment across countries. Demographic changes affect the aggregate accumulation of assets in two ways: by changing life expectancy which changes individual household saving behavior, and by changing the age distribution of the population by which individual household decisions are aggregated. We use a quantitative version of the model to illustrate the impact of demography on capital flows and net foreign assets in China, Germany, Japan, and the United States.
A multiply-by-3 coupled-ring oscillator for low-power frequency synthesis

A frequency-synthesis technique which extracts the Nth harmonic from an N-stage oscillator is presented. This technique enables significant power savings in the prescaler of a frequency synthesizer. The maximum achievable voltage swing from such an oscillator is estimated. To study this technique, a multiply-by-3 circuit with two 180/spl deg/-coupled single-ended three-stage ring oscillators has been fabricated in 0.24-/spl mu/m CMOS, designed to work in the 902-928-MHz ISM band (U.S. and Canada). It provides two outputs: one at the normal operating frequency of the oscillator and the other at three times that frequency. The circuit can work at voltages as low as 1.3 V, while consuming 210 /spl mu/A of current.
Mice that express human interleukin-8 have increased mobilization of immature myeloid cells, which exacerbates inflammation and accelerates colon carcinogenesis.

Background & Aims Interleukin (IL)-8 has an important role in initiating inflammation in humans, attracting immune cells such as neutrophils through their receptors CXCR1 and CXCR2. IL-8 has been proposed to contribute to chronic inflammation and cancer. However, mice do not have the IL-8 gene, so human cancer cell lines and xenograft studies have been used to study the role of IL-8 in colon and gastric carcinogenesis. We generated mice that carry a bacterial artificial chromosome that encompasses the entire human IL-8 gene, including its regulatory elements (IL-8Tg mice). Methods We studied the effects of IL-8 expression in APCmin +/− mice and IL-8Tg mice given azoxymethane and dextran sodium sulfate (DSS). We also examined the effects of IL-8 expression in gastric cancer in INS-GAS mice that overexpress gastrin and IL-8Tg mice infected with Helicobacter felis . Results In IL-8Tg mice, expression of human IL-8 was controlled by its own regulatory elements, with virtually no messenger RNA or protein detectable under basal conditions. IL-8 was strongly up-regulated on systemic or local inflammatory stimulation, increasing mobilization of immature CD11b + Gr-1 + myeloid cells (IMCs) with thioglycolate-induced peritonitis, DSS-induced colitis, and H. felis –induced gastritis. IL-8 was increased in colorectal tumors from patients and IL-8Tg mice compared with nontumor tissues. IL-8Tg mice developed more tumors than wild-type mice following administration of azoxymethane and DSS. Expression of IL-8 increased tumorigenesis in APCmin +/− mice compared with APCmin +/− mice that lack IL-8; this was associated with increased numbers of IMCs and angiogenesis in the tumors. Conclusions IL-8 contributes to gastrointestinal carcinogenesis by mobilizing IMCs and might be a therapeutic target for gastrointestinal cancers.
K2 of localisations of local rings

Abstract We show that K 2 of “sufficiently regular” localisations of local rings (e.g. inverting a sequence of regular parameters) can be described by the Steinberg presentation. The proof is inductive on the number of irreducible elements being inverted, successively using a generalisation of a co-Cartesian square first exploited by Dennis and Stein.
Massive star formation and feedback in W49A: the source of our Galaxy's most luminous water maser outflow★

We present high spatial resolution mid-infrared (IR) images of the ring of ultracompact H ii regions in W49A obtained at Gemini North, allowing us to identify the driving source of its powerful H2O maser outflow. These data also confirm our previous report that several radio sources in the ring are undetected in the mid-IR because they are embedded deep inside the cloud core. We locate the source of the water maser outflow at the position of the compact mid-IR peak of source G (source G:IRS1) to within 0. ′′ 07. This IR source is not coincident with any identified compact radio continuum source, but is coincident with a hot molecular core, so we propose that G:IRS1 is a hot core driving an outflow analogous to the wide-angle bipolar outflow in OMC-1. G:IRS1 is at the origin of a larger bipolar cavity and CO outflow. The water maser outflow is orthogonal to the bipolar CO cavity, so the masers probably reside near its waist in the thin cavity walls. Models of the IR emission require a massive protostar with M∗ ≃45 M⊙, L∗ ≃3×10 5 L⊙, and an effective envelope accretion rate of ∼10 −3 M⊙ yr −1 . Feedback from the central star could potentially drive the small-scale H2O maser outflow, but it has insufficient radiative momentum to have driven the largescale bipolar CO outflow, requiring that this massive star had an active accretion disk over the past 10 4 yr. Combined with the spatialy resolved morphology in IR images, G:IRS1 in W49 provides compelling evidence for a massive protostar that formed by accreting from a disk, accompanied by a bipolar outflow.
On the derivative of the generalized inverse of a matrix

An expression for the C4 inverse of a differential matrix Ais given whenever that inverse is differentiable.
Intracavity-pumped Raman laser action in a mid-IR, continuous-wave (cw) MgO:PPLN optical parametric oscillator

Intracavity-pumped Raman laser action in a fiber-laser–pumped, single-resonant, continuous-wave (cw) MgO:PPLN optical parametric oscillator with a high-Q linear resonator has been observed for the first time to our knowledge. Experimental results of this phenomenon investigation will be discussed.
Thermally stimulated H emission and diffusion in hydrogenated amorphous silicon

We report first principles ab initio density functional calculations of hydrogen dynamics in hydrogenated amorphous silicon. Thermal motion of the host Si atoms drives H diffusion, as we demonstrate by direct simulation and explain with simple models. Si-Si bond centers and Si ring centers are local energy minima as expected. We also describe a new mechanism for breaking Si-H bonds to release free atomic H into the network: fluctuating bond center detachment (FBCD)-assisted diffusion, in which a bond center H may be liberated by intercession of a third nearby Si. H dynamics in a-Si:H is dominated by structural fluctuations intrinsic to the amorphous phase not present in the crystal.
Matching Methods for Causal Inference: A Review and a Look Forward

When estimating causal effects using observational data, it is desirable to replicate a randomized experiment as closely as possible by obtaining treated and control groups with similar covariate distributions. This goal can often be achieved by choosing well-matched samples of the original treated and control groups, thereby reducing bias due to the covariates. Since the 1970's, work on matching methods has examined how to best choose treated and control subjects for comparison. Matching methods are gaining popularity in fields such as economics, epidemiology, medicine, and political science. However, until now the literature and related advice has been scattered across disciplines. Researchers who are interested in using matching methods-or developing methods related to matching-do not have a single place to turn to learn about past and current research. This paper provides a structure for thinking about matching methods and guidance on their use, coalescing the existing research (both old and new) and providing a summary of where the literature on matching methods is now and where it should be headed.
Scalar-linear solvability of matroidal networks associated with representable matroids

We study matroidal networks introduced by Dougherty et al., who showed that if a network is scalar-linearly solvable over some finite field, then the network is a matroidal network associated with a representable matroid over a finite field. In this paper, we prove the converse. It follows that a network is scalar-linearly solvable if and only if the network is a matroidal network associated with a representable matroid over a finite field and that determining scalar-linear solvability of a network is equivalent to finding a representable matroid over a finite field and a valid network-matroid mapping. As a consequence, we obtain a correspondence between scalar-linearly solvable networks and representable matroids over finite fields. We note that this result, combined with the construction method due to Dougherty et al., can generate potentially new scalar-linearly solvable networks.
Improving Gate-Level Simulation of Quantum Circuits

Simulating quantum computation on a classical computer is a difficult problem. The matrices representing quantum gates, and the vectors modeling qubit states grow exponentially with an increase in the number of qubits. However, by using a novel data structure called the Quantum Information Decision Diagram (QuIDD) that exploits the structure of quantum operators, a useful subset of operator matrices and state vectors can be represented in a form that grows polynomially with the number of qubits. This subset contains, but is not limited to, any equal superposition of n qubits, any computational basis state, n-qubit Pauli matrices, and n-qubit Hadamard matrices. It does not, however, contain the discrete Fourier transform (employed in Shor's algorithm) and some oracles used in Grover's algorithm. We first introduce and motivate decision diagrams and QuIDDs. We then analyze the runtime and memory complexity of QuIDD operations. Finally, we empirically validate QuIDD-based simulation by means of a general-purpose quantum computing simulator QuIDDPro implemented in C++. We simulate various instances of Grover's algorithm with QuIDDPro, and the results demonstrate that QuIDDs asymptotically outperform all other known simulation techniques. Our simulations also show that well-known worst-case instances of classical searching can be circumvented in many specific cases by data compression techniques. PACS: 03.67.Lx, 03.65.Fd, 03.65.Vd, 07.05.Bx
Reactivity of Ruthenium(II) and Copper(I) Complexes that Possess Anionic Heteroatomic Ligands: Synthetic Exploitation of Nucleophilicity and Basicity of Amido, Hydroxo, Alkoxo, and Aryloxo Ligands for the Activation of Substrates that Possess Polar Bonds as well as Nonpolar C–H and H–H Bonds

The preparation and reactivity of late transition-metal complexes in low oxidation states with nondative-heteroatomic ligands (e.g., amido, hydroxo, alkoxo, and aryloxo ligands) are described. For such complexes the disruption of ligand-to-metal π-donation because of a filled dπ manifold can enhance the nucleophilic and/or basic reactivity at the nondative-heteroatomic ligand relative to transition-metal complexes in high oxidation states. The chemistry of five- and six-coordinate Ru complexes with amido, hydroxo, methoxo, and aryloxo ligands is described including Bronsted acid/base reactions, coordination, and activation of polar substrates toward N–C bond forming reactions and metal-mediated activation of dihydrogen and C–H bonds. The impact of ancillary ligands and Ru oxidation states (RuII versus RuIII) are discussed. In addition, the preparation and reactivity of well-defined monomeric two- and three-coordinate Cu complexes with amido, alkoxo, hydroxo, and aryloxo ligands are presented including examples of reactions to probe fundamental reactivity patterns as well as catalytic addition of N–H and O–H bonds across C=C bonds of olefins. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Theoretical Performance Of Mid-Infrared Broken-Gap Multilayer Superlattice Lasers

We present calculations of the intersubband absorption and Auger recombination rate of superlattices based on the InAs/GaInSb material system involving more than two layers in the repeating unit cell and strain balanced to match the GaSb substrate. We demonstrate theoretically the presence of final-state optimization in a 4.0 μm strain-balanced brokengap superlattice. This system's band structure is optimized not only at the band edge, where the valence density of states has been reduced, but also at resonance energies, where reside final states for Auger and intersubband processes. The spectral structure of the intersubband absorption, which for some wavelengths near the lasing wavelength can exceed 500 cm −1 at lasing threshold, has been considered when designing this active region. Fortunately, final-state optimized designs which minimize Auger recombination tend to minimize intersubband absorption as well. The effectiveness of final-state optimization is evaluated by considering band structures with identical band edge structure, but different final-state structure.
Radiation of Mixed Layer Near-Inertial Oscillations into the Ocean Interior

The radiation from the mixed layer into the interior of the ocean of near-inertial oscillations in the presence of the beta effect is reconsidered as an initial-value problem. Making use of the fact that the mixed layer depth is much smaller than the total depth of the ocean, the solution is obtained in the limit of an ocean that is effectively infinitely deep. For a uniform initial condition, analytical results for the velocity, horizontal kinetic energy density, and fluxes are obtained. This is the canonical solution for the radiation of near-inertial oscillations in the vertical, which captures the basic mechanisms due to the beta effect, and leads to the formation of small scales in the vertical. By superposing events, an average vertical wavenumber spectrum is constructed. The predicted decay of near-inertial mixed layer energy in the presence of the beta effect occurs on a timescale similar to that observed.
Subjective assessment of fever by parents: comparison with measurement by noncontact tympanic thermometer and calibrated rectal glass mercury thermometer

Study objective: To assess the ability of parents to subjectively evaluate their children for fever and to compare their assessments with temperature measurements made with the use of a noncontact tympanic (NCT) or rectal glass mercury thermometer. A secondary goal was to assess how well a recently developed definition of fever for NCT thermometers, when used in the ear-equivalent mode (temperature of 37.7° C or more), performed in a clinical situation. Methods: This 6-month prospective observational study employed a convenience sample of 180 children, aged birth to 4 years, who presented to the emergency department of a tertiary care children's hospital. Parents were asked to subjectively assess whether their child had a fever. The child's temperature was then measured with an NCT thermometer (three times in the rectal-equivalent mode and three times in the actual-ear mode). Both the subjective assessment and the NCT temperatures were compared with the rectal temperature measured by a rectal glass mercury thermometer. Results: The mean age of participants was 14.6±11.8 months (range, 2 days to 48 months); 56% were boys. The sensitivity of parental detection of fever by subjective means was 81.8% and the specificity 76.5%. The parent and the rectal glass thermometer agreed 79% of the time (95% confidence interval [CI], 73% to 85%). The sensitivity of the first temperature reading obtained with the NCT thermometer in rectal-equivalent mode was 74.7%, and the specificity was 96.3%. The NCT thermometer and the rectal glass thermometer agreed 84% of the time (95% CI, 78% to 89%). Use of the proposed definition of fever for NCT thermometers, when used in the ear-equivalent mode, caused sensitivity of a single measurement for fever to drop to 53.5%. Conclusion: Parental subjective assessment of fever agreed with the presence of fever as measured by rectal glass thermometer in 79% of cases. Specificity was improved with the use of the NCT thermometer. The recently proposed definition for fever for NCT thermometers, when they are used in the ear-equivalent mode, does not appear to be validated by the current data. (Hooker EA, Smith SW, Miles T, King L: Subjective assessment of fever by parents: Comparison with measurement by noncontact tympanic thermometer and calibrated rectal glass mercury thermometer. Ann Emerg Med September 1996;28:313–317.)
BUILDING BRAND EQUITY THROUGH CORPORATE SOCIETAL MARKETING

Abstract Marketers have shown increasing interest in the use of corporate societal marketing (CSM) programs. In this article, the authors describe six means by which CSM programs can build brand equity: (1) building brand awareness, (2) enhancing brand image, (3) establishing brand credibility, (4) evoking brand feelings, (5) creating a sense of brand community, and (6) eliciting brand engagement. The authors also address three key questions revolving around how CSM programs have their effects, which cause the firm should choose, and how CSM programs should be branded. The authors offer a series of research propositions throughout and conclude by outlining a set of potential future research directions.
Trade Dynamics in the Market for Federal Funds

We develop a model of the market for federal funds that explicitly accounts for its two distinctive features: banks have to search for a suitable counterparty, and once they have met, both parties negotiate the size of the loan and the repayment. The theory is used to answer a number of positive and normative questions: What are the determinants of the fed funds rate? How does the market reallocate funds? Is the market able to achieve an efficient reallocation of funds? We also use the model for theoretical and quantitative analyses of policy issues facing modern central banks.
Efficient Regio- and Stereocontrolled Synthesis of Highly Functionalized Polycyclic Systems Using the Diels-Alder Addition of Stannyl-Substituted Vinylketeneacetals

The vinylketeneacetal obtained by deprotonation-silylation of methyl 3-trimethylstannyl-2-butenoate undergoes Diels-Alder addition regiospecifically with 5-hydroxy-1,4-naphthoquinone to lead to organometallic derivatives in which the organic portion is a differentially protected polyketonic hydroanthracene system.
Breaking and making quantum money: toward a new quantum cryptographic protocol

Public-key quantum money is a cryptographic protocol in which a bank can create quantum states which anyone can verify but no one except possibly the bank can clone or forge. There are no secure public-key quantum money schemes in the literature; as we show in this paper, the only previously published scheme (1) is insecure. We introduce a category of quantum money protocols which we call collision-free. For these protocols, even the bank cannot prepare multiple identical- looking pieces of quantum money. We present a blueprint for how such a protocol might work as well as a concrete example which we believe may be insecure.
The time-sequenced adaptive filter

A new form of adaptive filter is proposed which is especially suited for the estimation of a class of nonstationary signals. This new filter, called the time-sequenced adaptive filter, is an extension of the least mean-square error (LMS) adaptive filter. Both the LMS and timesequenced adaptive filters are digital filters composed of a tapped delay line and adjustable weights, whose impulse response is controlled by an adaptive algorithm. For stationary stochastic inputs the mean-square error, which is the expected value of the squared difference between the filter output and an externally supplied "desired response," is a quadratic function of the weights--a paraboloid with a single fixed minimum point which can be sought by gradient techniques, such as the LMS algorithm. For nonstationary inputs however the minimum point, curvature, and orientation of the error surface could be changing over time. The time-sequenced adaptive filter is applicable to the estimation of that subset of nonstationary signals having a recurring (but not necessarily periodic) statistical character, e.g., recurring pulses in noise. In this case there are a finite number of different paraboloidal error surfaces, also recurring in time. The time-sequenced adaptive filter uses multiple sets of adjustable weights. At each point in time, one and only one set of weights is selected to form the filter output and to be adapted using the LMS algorithm. The index of the set of weights chosen is synchronized with the recurring statistical character of the filter input so that each set of weights is associated with a single error surface. After many adaptations of each set of weights, the minimum point of each error surface is reached resulting in an optimal time-varying filter. For this procedure, some a priori knowledge of the filter input is required to synchronize the selection of the set of weights with the recurring statistics of the filter input. For pulse-type signals, this a priori knowledge could be the location of the pulses in time; for signals with periodic statistics, knowledge of the period is sufficient. Possible applications of the time-sequenced adaptive filter include electrocardiogram enhancement and electric load prediction.
A Nonlinear Factor Analysis of S&P 500 Index Option Returns

Growing evidence suggests that extraordinary average returns may be obtained by trading equity index options, and that at least part of this abnormal performance is attributable to volatility and jump risk premia. This paper asks whether such priced risk factors are alone sufficient to explain these average returns. To provide an answer in as general as possible a setting, I estimate a flexible class of nonlinear models using all S&P 500 Index futures options traded between 1986 and 2000. The results show that priced factors contribute to these expected returns but are insufficient to explain their magnitudes, particularly for short-term out-of-the-money puts. IN A RECENT PAPER ,C OVAL AND SHUMWAY (2001) examine the returns on deltahedged option positions, focusing on the at-the-money straddle, and find average returns close to minus 3% per week. Since over short time horizons these positions are approximately invariant to movements in the underlying index, Coval and Shumway argue that their CAPM betas should be near zero and their expected returns close to the risk-free rate. They conclude that large deviations from the CAPM are the norm, which they suggest is evidence that some other systematic factor, such as stochastic volatility, might be priced by the market. Similar conclusions are made by Jackwerth (2000), who finds risk-adjusted profitability from selling puts, and by Bakshi and Kapadia (2003), who find that the volatility risk premium contributes significantly to higher prices for calls and puts. Buraschi and Jackwerth (2001) concur, suggesting that more than one priced risk factor is necessary to explain option prices. A less direct set of evidence is the now standard observation that the Black‐ Scholes implied volatilities of equity index options are upward-biased predictors of future realized volatility. Numerous studies, such as Fleming, Ostdiek, and Whaley (1995) and Christensen and Prabhala (1998), document that implied volatilities of short-term at-the-money equity index options are on average several percentage points higher than the volatilities realized over the option’s
F-theory and neutrinos: Kaluza-Klein dilution of flavor hierarchy

We study minimal implementations of Majorana and Dirac neutrino scenarios in Ftheory GUT models. In both cases the mass scale of the neutrinos m M 2 weak = UV arises from integrating out Kaluza-Klein modes, where UV is close to the GUT scale. The participation of non-holomorphic Kaluza-Klein mode wave functions dilutes the mass hierarchy in comparison to the quark and charged lepton sectors, in agreement with experimentally measured mass splittings. The neutrinos are predicted to exhibit a \normal" mass hierarchy, with masses (m3;m2;m1) :05 (1; 1=2 GUT ; GUT ) eV. When the interactions of the neutrino and charged lepton sectors geometrically unify, the neutrino mixing matrix exhibits a mild hierarchical structure such that the mixing angles 23 and 12 are large and comparable,
Who Benefits from Marriage

The phenomenon that married men earn higher average wages than unmarried men, the so-called marriage premium, is well known. However, the robustness of the marriage premium across the wage distribution and the underlying causes of the marriage premium deserve closer scrutiny. Focusing on the entire wage distribution and employing recently developed semi-nonparametric tests for quantile treatment effects, our findings cast doubt on the robustness of the premium. We find that the premium is explained by selection above the median, whereas a positive premium is obtained only at very low wages. We argue that the causal effect at low wages is probably attributable to employer discrimination.
Implications of Ubiquitous Computing for the Social Studies Curriculum

In March 2002, members of the National Technology Leadership Initiative (NTLI) met in Charlottesville, Virginia to discuss the potential effects of ubiquitous computing on the field of education. Ubiquitous computing, or “on-demand availability of task-necessary computing power,” involves prov iding every student with a handheld computer—a situation with enormous repercussions for education and teacher education. Over a two day period, participants engaged in intensive discussion of the issue of ubiquitous computing and developed seven conclusio ns. This paper, written by the representatives from social studies organizations, seeks to examine the specific implications of these seven conclusions for the field of social studies education. The paper discusses the concept of ubiquitous computing and the impact this technology shift may have on social studies curricula, teacher preparation, software development, and research agendas.
DC Transformer and DC Josephson(-like) Effects in Quantum Hall Bilayers

In the early days of superconductivity, Ivar Giaver discovered that it was possible to make a novel DC transformer by using one superconductor to drag vortices through another. An analogous effect was predicted to exist in quantum Hall bilayers and has recently been discovered experimentally by Eisenstein's group at Caltech. Similarly, new experiments from the Caltech group have demonstrated the existence of a Josephson-like 'supercurrent' branch for electrons coherently tunnelling between the two layers.
Unidentified EGRET sources and the extragalactic gamma-ray background

The large majority of EGRET point sources remain to this day without an identified low-energy counterpart. Whatever the nature of the EGRET unidentified sources, faint unresolved objects of the same class must have a contribution to the diffuse gamma-ray background: if most unidentified objects are extragalactic, faint unresolved sources of the same class contribute to the background, as a distinct extragalactic population; on the other hand, if most unidentified sources are Galactic, their counterparts in external galaxies will contribute to the unresolved emission from these systems. Understanding this component of the gamma-ray background, along with other guaranteed contributions from known sources, is essential in any attempt to use gamma-ray observations to constrain exotic high-energy physics. Here, we follow an empirical approach to estimate whether a potential contribution of unidentified sources to the extragalactic gamma-ray background is likely to be important, and we find that it is. Additionally, we comment on how the anticipated GLAST measurement of the diffuse gamma-ray background will change, depending on the nature of the majority of these sources.
Changes in rainfall seasonality in the tropics

Climate change is altering the seasonal distribution, interannual variability and overall magnitude of precipitation. A new global measure of precipitation seasonality is proposed, and application of this method to observations from the tropics shows that increases in variability were accompanied by shifts in seasonal magnitude, timing and duration.
Risk Perceptions of Arsenic in Tap Water and Consumption of Bottled Water

[1] The demand for bottled water has increased rapidly over the past decade, but bottled water is extremely costly compared to tap water. The convenience of bottled water surely matters to consumers, but are others factors at work? This manuscript examines whether purchases of bottled water are associated with the perceived risk of tap water. All of the past studies on bottled water consumption have used simple scale measures of perceived risk that do not correspond to risk measures used by risk analysts. We elicit a probability-based measure of risk and find that as perceived risks rise, expenditures for bottled water rise.
Reflections on the magnetic pair distribution function

The recent application of the total scattering method to magnetic systems is discussed. The ability to determine the magnetic pair distribution function opens the door to the study of local order in magnetic systems ranging from multiferroics to dilute magnetic semiconductors.
Effectiveness of job search interventions: a meta-analytic review.

The current meta-analytic review examined the effectiveness of job search interventions in facilitating job search success (i.e., obtaining employment). Major theoretical perspectives on job search interventions, including behavioral learning theory, theory of planned behavior, social cognitive theory, and coping theory, were reviewed and integrated to derive a taxonomy of critical job search intervention components. Summarizing the data from 47 experimentally or quasi-experimentally evaluated job search interventions, we found that the odds of obtaining employment were 2.67 times higher for job seekers participating in job search interventions compared to job seekers in the control group, who did not participate in such intervention programs. Our moderator analysis also suggested that job search interventions that contained certain components, including teaching job search skills, improving selfpresentation, boosting self-efficacy, encouraging proactivity, promoting goal setting, and enlisting social support, were more effective than interventions that did not include such components. More important, job search interventions effectively promoted employment only when both skill development and motivation enhancement were included. In addition, we found that job search interventions were more effective in helping younger and older (vs. middle-aged) job seekers, short-term (vs. long-term) unemployed job seekers, and job seekers with special needs and conditions (vs. job seekers in general) to find employment. Furthermore, meta-analytic path analysis revealed that increased job search skills, job search self-efficacy, and job search behaviors partially mediated the positive effect of job search interventions on obtaining employment. Theoretical and practical implications and future research directions are discussed.
COMPLEX UNIT ROOTS AND BUSINESS CYCLES: ARE THEY REAL?

In this paper the asymptotic properties of ARMA processes with complex-conjugate unit roots in the AR lag polynomial are stud- ied. These processes behave quite dierently from regular unit root processes (with a single root equal to 1). In particular, the asymp- totic properties of a standardized version of the periodogram for such processes are analyzed, and a nonparametric test of the complex unit root hypothesis against the stationarity hypothesis is derived. This test is applied to the annual change of the monthly number of unem- ployed in the US, in order to see whether this time series has complex unit roots in the business cycle frequencies.
Localized photonic band edge modes and orbital angular momenta of light in a golden-angle spiral

A golden-angle spiral lattice can posses an omnidirectional photonic bandgap despite the lack of translational and rotational symmetries. We show that the band edge modes are spatially localized and possess discrete angular momenta.