cssi/SciSciGPT-SciSciNet huggingface dataset:
Direct gamete sequencing reveals no evidence for segregation distortion in house mouse hybrids.

Understanding the molecular basis of species formation is an important goal in evolutionary genetics, and Dobzhansky-Muller incompatibilities are thought to be a common source of postzygotic reproductive isolation between closely related lineages. However, the evolutionary forces that lead to the accumulation of such incompatibilities between diverging taxa are poorly understood. Segregation distorters are believed to be an important source of Dobzhansky-Muller incompatibilities between hybridizing species of Drosophila as well as hybridizing crop plants, but it remains unclear if these selfish genetic elements contribute to reproductive isolation in other taxa. Here, we collected viable sperm from first-generation hybrid male progeny of Mus musculus castaneus and M. m. domesticus, two subspecies of rodent in the earliest stages of speciation. We then genotyped millions of single nucleotide polymorphisms in these gamete pools and tested for a skew in the frequency of parental alleles across the genome. We show that segregation distorters are not measurable contributors to observed infertility in these hybrid males, despite sufficient statistical power to detect even weak segregation distortion with our novel method. Thus, reduced hybrid male fertility in crosses between these nascent species is attributable to other evolutionary forces.
A subspace algorithm for simultaneous identification and input reconstruction

This paper considers the concept of input and state observability, that is, conditions under which both the unknown input and initial state of a known model can be determined from output measurements. We provide necessary and sufficient conditions for input and state observability in discrete-time systems. Next, we develop a subspace identification algorithm that identifies the state-space matrices and reconstructs the unknown input using output measurements and known inputs. Finally, we present several illustrative examples, including a nonlinear system in which the unknown input is due to the endogenous nonlinearity. Copyright © 2008 John Wiley & Sons, Ltd.
A Geometric Interpretation of Fading in Wireless Networks: Theory and Applications

In wireless networks with random node distribution, the underlying point process model and the channel fading process are usually considered separately. A unified framework is introduced that permits the geometric characterization of fading by incorporating the fading process into the point process model. Concretely, assuming nodes are distributed in a stationary Poisson point process in Rd , the properties of the point processes that describe the path loss with fading are analyzed. The main applications are single-hop connectivity and broadcasting.
Kolmogorov-Burgers Model for Star-forming Turbulence

The process of star formation in interstellar molecular clouds is believed to be controlled by driven supersonic magnetohydrodynamic turbulence. We suggest that in the inertial range, such turbulence obeys the Kolmogorov law, while in the dissipative range, it behaves as Burgers turbulence developing shock singularities. On the base of the She-Leveque analytical model, we then predict the velocity power spectrum in the inertial range to be Ek ~ k-1.74. This result agrees well with recent numerical findings by Padoan & Nordlund and reproduces the observational Larson law u ~ l0.74...0.76. The application of the model to more general dissipative structures with higher fractal dimensionality is discussed.
Specialization of linear systems from curves to graphs

We investigate the interplay between linear systems on curves and graphs in the context of specialization of divisors on an arithmetic surface. We also provide some applications of our results to graph theory, arithmetic geometry, and tropical geometry.
A solution to the mysteries of morality.

We propose that moral condemnation functions to guide bystanders to choose the same side as other bystanders in disputes. Humans interact in dense social networks, and this poses a problem for bystanders when conflicts arise: which side, if any, to support. Choosing sides is a difficult strategic problem because the outcome of a conflict critically depends on which side other bystanders support. One strategy is siding with the higher status disputant, which can allow bystanders to coordinate with one another to take the same side, reducing fighting costs. However, this strategy carries the cost of empowering high-status individuals to exploit others. A second possible strategy is choosing sides based on preexisting relationships. This strategy balances power but carries another cost: Bystanders choose different sides, and this discoordination causes escalated conflicts and high fighting costs. We propose that moral cognition is designed to manage both of these problems by implementing a dynamic coordination strategy in which bystanders coordinate side-taking based on a public signal derived from disputants’ actions rather than their identities. By focusing on disputants’ actions, bystanders can dynamically change which individuals they support across different disputes, simultaneously solving the problems of coordination and exploitation. We apply these ideas to explain a variety of otherwise mysterious moral phenomena.
Justifying Imprisonment: On the Optimality of Excessively Costly Punishment

The criminal punishment literature has focused on justifying non-maximal punishments and the use of non-monetary sanctions. It has not addressed why imprisonment, rather than cheaper forms of corporal punishment, should be the dominant type of non-monetary sanctions. David Friedman (1999) recently hypothesized that, because convicts lack political influence, it is desirable to make punishment more costly than necessary to prevent policy makers from excessively punishing convicts. This paper explicitly models this hypothesis and uses simulations to determine under what circumstances this hypothesis justifies using imprisonment rather than cheaper non-monetary sanctions.
Damage resistance and tolerance of carbon/epoxy composite coupons subjected to simulated lightning strike

Damage is inflicted in a series of carbon fiber/epoxy composite specimens using a simulated lightning strike generator in the effort to understand the fundamental damage response of this material form. The strikes up to 50,000 A and 28,000 V are inflicted on both pristine specimens and specimens containing a Hilok stainless steel fastener. Damage area is evaluated via ultrasonic scanning, and advanced optical microscopy is used to gain further understanding in the morphology of damage. Subsequent mechanical testing to assess the residual tensile and compressive strength and modulus of the material is performed according to ASTM standards. Results show that residual tension strength counter intuitively increases after the infliction of damage, while residual compressive strength is much more dramatically and negatively affected. Furthermore, the presence of the fastener influences dramatically both the state of damage in the specimen and its residual strength by spreading throughout the thickness rather than limiting it to the specimen surface.
Perceptions of per diems in the health sector: evidence and implications

Per diems are used to pay work-related expenses and motivate employees, yet they also can distort incentives and may be abused. This study was designed to explore perceptions of per diems among 41 high-, mid- and low-level government officers and non-governmental organization (NGO) officials in Malawi and Uganda. Interviews explored attitudes about per diems, benefits and problems for organizations and individuals, and risks and patterns of abuse. The study found that per diems provide benefits such as encouraging training, increasing staff motivation and supplementing salary. Despite these advantages, respondents voiced many discontents about per diems, stating that they create conflict, contribute to a negative organizational culture where people expect to be paid for all activities, and lead to negative changes in work time allocation. Work practices are also manipulated in order to maximize financial gain by slowing work, scheduling unnecessary trainings, or exaggerating time needed for tasks. Officials may appropriate per diems meant for others or engage in various forms of fraud for personal financial gain. Abuse seemed more common in the government sector due to low pay and weaker controls. A striking finding was the distrust that lower-level workers felt toward their superiors: allowances were perceived to provide unfair financial advantages to already better-off and well-connected staff. To curb abuse of per diems, initiatives must reduce pressures and incentives to abuse, while controlling discretion and increasing transparency in policy implementation. Donors can play a role in reform by supporting development of policy analysis tools, design of control mechanisms and evaluation of reform strategies.
THE QUASAR/GALAXY PAIR PKS 1327-206/ESO 1327-2041: ABSORPTION ASSOCIATED WITH A RECENT GALAXY MERGER

We present HST/WFPC2 broadband and ground-based Hα images, H I 21 cm emission maps, and low-resolution optical spectra of the nearby galaxy ESO 1327-2041, which is located 38'' (14 h –1 70 kpc in projection) west of the quasar PKS 1327-206. Our Hubble Space Telescope (HST) images reveal that ESO 1327-2041 has a complex optical morphology, including an extended spiral arm that was previously classified as a polar ring. Our optical spectra show Hα emission from several H II regions in this arm located ~5'' from the quasar position (~2 h –1 70 kpc in projection) and our ground-based Hα images reveal the presence of several additional H II regions in an inclined disk near the galaxy's center. Absorption associated with ESO 1327-2041 is found in H I 21 cm, optical, and near-UV spectra of PKS 1327-206. We find two absorption components at cz abs = 5255 and 5510 km s–1 in the H I 21 cm absorption spectrum, which match the velocities of previously discovered metal-line components. We attribute the 5510 km s–1 absorber to disk gas in the extended spiral arm and the 5255 km s–1 absorber to high-velocity gas that has been tidally stripped from the disk of ESO 1327-2041. The complexity of the galaxy/absorber relationships for these very nearby H I 21 cm absorbers suggests that the standard view of high-redshift damped Lyα absorbers is oversimplified in many cases.
On the Query Complexity of Clique Size and Maximum Satisfiability

This paper explores the bounded query complexity of approximating the size of the maximum clique in a graph (Clique Size) and the number of simultaneously satisfiable clauses in a 3CNF formula (MaxSat). The results in the paper show that for certain approximation factors, approximating Clique Size and MaxSat are complete for corresponding bounded query classes under metric reductions. The completeness result is important because it shows that queries and approximation are interchangeable: NP queries can be used to solve NP-approximation problems and solutions to NP-approximation problems answer queries to NP oracles. Completeness also shows the existence of approximation preserving reductions from many NP-approximation problems to approximating Clique Size and MaxSat (e.g., from approximating Chromatic Number to approximating Clique Size). Since query complexity is a quantitative complexity measure, these results also provide a framework for comparing the complexities of approximating Clique Size and approximating MaxSat. In addition, this paper examines the query complexity of the minimization version of the satisfiability problem, MinUnsat, and shows that the complexity of approximating MinUnsat is very similar to the complexity of approximating Clique Size. Since MaxSat and MinUnsat share the same solution space, the “approximability” of MaxSat is not due to the intrinsic complexity of satisfiability, but is an artifact of viewing the approximation version of satisfiability as a maximization problem.
(1E,3E)-4-acetoxy-1-phenyldimethylsilyl-1,3-butadiene as a surrogate for (1E,3E)-1,4- diacetoxy-1,3-butadiene: a highly efficient synthesis of (+/-)-shikimic acid

Abstract The 5-step synthesis of (±)-shikimic acid has been achieved in 55% overall yield from (1 E ,3 E )-4-acetoxy-1-phenyldimethylsilyl-1,3-butadiene, starting with its Diels-Alder reaction with 2-(trimethylsilyl)ethyl acrylate and featuring the use of Fleming's one-pot procedure for the conversion of the phenyldimethylsilyl group to the hydroxyl as the salient, pivotal step in the synthesis.
British Industrialization and the Profit Constraint Hypothesis: The Case of a Manchester Cotton Enterprise, 1798-1827

This paper test the hypothesis that capital market imperfections constrained the growth of British firms during the Industrial Revolution. Using data on the cost structure of a representative British cotton manufacturer during the 1798 to 1827 period, this paper shows that the scale of operation was too small. The findings suggests that industrialization could have proceeded more rapidly if firms would have had access to alternative sources of capital financing.
Microfluidic preparative free-flow isoelectric focusing in a triangular channel: system development and characterization.

A preparative scale free-flow isoelectric focusing (FF-IEF) device is developed and characterized with the aim of addressing needs of molecular biologists working with protein samples on the milligrams and milliliters scale. A triangular-shape separation channel facilitates the establishment of the pH gradient with a corresponding increase in separation efficiency and decrease in focusing time compared to that in a regular rectangular channel. Functionalized, ion-permeable poly (acrylamide) gel membranes are sandwiched between poly (dimethyl silxoane) (PDMS) and glass layers to both isolate the electrode buffers from the central separation channel and also to selectively adjust the voltage efficiency across separation channel to achieve high electric field separation. The 50 × 70 mm device is fabricated by soft lithography and has 24 outlets evenly spaced across a pH gradient between pH 4 and 10. This preparative FF-IEF system is investigated and optimized for both aqueous and denaturing conditions with respect to the electric field and potential efficiency and with consideration of Joule-heating removal. Energy distribution across the functionalized polyacrylamide gel is investigated and controlled to adjust the potential efficiency between 15 - 80% across the triangular separation channel. The device is able to achieve constant electric fields high as 370 ± 20 V/cm through the entire triangular channel given the separation voltage of 1800 V, enabling separation of five fluorescent pI markers as a demonstration example.
Better Living: Toward a Cultural History of a Business Slogan

This article traces the migration of the slogan “better living” from its inception in 1935 as an attempt to clean up the corporate image of Du Pont, through its dissemination into the building trades and architecture during and after World War II, and finally into urban planning in the postwar decades. These fields borrowed the phrase back and forth in their promotional literature in order to serve their own, often clashing agendas—one strand of the larger contest between the forces of free enterprise and those of centralized planning and reform. The essay aims to bring together aspects of business, architecture, and planning in order to explore the fertile cultural milieu these different fields shared in the middle decades of the twentieth century. In 1935 the advertising firm Batten, Barton, Durstine and Osborn (BBD&O) proposed the now-famous Du Pont slogan, “Better Things for Better Living.” What might at first appear to be an appeal to mass consumption veiled an important public relations move. Du Pont was under siege. The company had figured prominently in the 1934 book Merchants of Death, which exposed American corporate profiteering during World War I. 1 “Better things for better living through
KEEP UP THE GOOD WORK? AN EVALUATION OF THE USDA'S LIVESTOCK PRICE FORECASTS

One step-ahead forecasts of quarterly live cattle, live hog, and broiler prices are evaluated under two general approaches: accuracy-based measures and the ability to categorize price movements directionally or within a forecasted range. Results suggest USDA price forecasts are not optimal. Broiler price forecasts are biased, and all the forecast series tend to repeat errors. While the USDA forecasts are more accurate that those of a univariate AR(4) time series model, the evidence suggests that live cattle forecasts could be improved with a composite forecast. However, the USDA correctly identifies the direction of price change in at least 70% of its forecasts. Prices fall within the USDA's forecasted range 48% of the time for broilers but only 35% for hogs. Finally, there is some evidence that the USDA's price forecasting accuracy has improved over time for broilers, but it has gotten marginally worse for hogs.
ORPHANS AND SCHOOLING IN AFRICA: A LONGITUDINAL ANALYSIS*

AIDS deaths could have a major impact on economic development by affecting the human capital accumulation of the next generation. We estimate the impact of parent death on primary school participation using an unusual five-year panel data set of over 20,000 Kenyan children. There is a substantial decrease in school participation following a parent death and a smaller drop before the death (presumably due to pre-death morbidity). Estimated impacts are smaller in specifications without individual fixed effects, suggesting that estimates based on cross-sectional data are biased toward zero. Effects are largest for children whose mothers died and, in a novel finding, for those with low baseline academic performance.
Adaptive Triangular Deployment Algorithm for Unattended Mobile Sensor Networks

In this paper, we present a novel sensor deployment algorithm, called the adaptive triangular deployment (ATRI) algorithm, for large-scale unattended mobile sensor networks. The ATRI algorithm aims at maximizing coverage area and minimizing coverage gaps and overlaps by adjusting the deployment layout of nodes close to equilateral triangulation, which is proven to be the optimal layout to provide the maximum no-gap coverage. The algorithm only needs the location information of nearby nodes, thereby avoiding communication cost for exchanging global information. By dividing the transmission range into six sectors, each node adjusts the relative distance to its one-hop neighbors in each sector separately. The distance threshold strategy and the movement state diagram strategy are adopted to avoid the oscillation of nodes. The simulation results show that the ATRI algorithm achieves a much larger coverage area and smaller average moving distance of nodes than existing algorithms. We also show that the ATRI algorithm is applicable to practical environments and tasks such as working in both bounded and unbounded areas and avoiding irregularly shaped obstacles. In addition, the density of nodes can be adjusted adaptively to different requirements of tasks.
The Velocity distribution of isolated radio pulsars

We infer the velocity distribution of radio pulsars based on large-scale 0.4 GHz pulsar surveys. We do so by modelling evolution of the locations, velocities, spins, and radio luminosities of pulsars; calculating pulsed flux according to a beaming model and random orientation angles of spin and beam; applying selection effects of pulsar surveys; and comparing model distributions of measurable pulsar properties with survey data using a likelihood function. The surveys analyzed have well-defined characteristics and cover approx. 95% of the sky. We maximize the likelihood in a 6-dimensional space of observables P, dot-P, DM, absolute value of b, mu, F (period, period derivative, dispersion measure, Galactic latitude, proper motion, and flux density). The models we test are described by 12 parameters that characterize a population's birth rate, luminosity, shutoff of radio emission, birth locations, and birth velocities. We infer that the radio beam luminosity (i) is comparable to the energy flux of relativistic particles in models for spin-driven magnetospheres, signifying that radio emission losses reach nearly 100% for the oldest pulsars; and (ii) scales approximately as E(exp 1/2) which, in magnetosphere models, is proportional to the voltage drop available for acceleration of particles. We find that a two-component velocity distribution with characteristic velocities of 90 km/ s and 500 km/ s is greatly preferred to any one-component distribution; this preference is largely immune to variations in other population parameters, such as the luminosity or distance scale, or the assumed spin-down law. We explore some consequences of the preferred birth velocity distribution: (1) roughly 50% of pulsars in the solar neighborhood will escape the Galaxy, while approx. 15% have velocities greater than 1000 km/ s (2) observational bias against high velocity pulsars is relatively unimportant for surveys that reach high Galactic absolute value of z distances, but is severe for spatially bounded surveys; (3) an important low-velocity population exists that increases the fraction of neutron stars retained by globular clusters and is consistent with the number of old objects that accrete from the interstellar medium; (4) under standard assumptions for supernova remnant expansion and pulsar spin-down, approx. 10% of pulsars younger than 20 kyr will appear to lie outside of their host remnants. Finally, we comment on the ramifications of our birth velocity distribution for binary survival and the population of inspiraling binary neutron stars relevant to some GRB models and potential sources for LIGO.
Application of hadamard transform to fiber‐optic smart‐skin sensing

An array of optical fibers can be applied to smart-skin sensing applications, which include stress monitoring, fatigue detection, temperature sensing, etc. Although a single light source can be used in a fiber array sensor, the input light power is divided by a sensing fiber array and each fiber may require a detector. Thus as the channel number of a fiber array increases, the number of detectors also increases and the signal intensity of each fiber channel decreases, which decreases the signal-to-noise ratio and increases the complexity and the cost of the system. In this article we will analyze the Hadamard transform to enhance the signal processing of the fiber array sensor. The apparent advantages are that only one detector is needed and the signal-to-noise ratio of the fiber array sensor can be improved by a factor of N/2, where N is the number of sensing fibers. Analysis for an array of 127 sensing fibers is illustrated, in which we have shown that the calculated results are in agreement with the analytical model. © 1993 John Wiley & Sons, Inc.
Genotyping errors, pedigree errors, and missing data.

Our group studied the effects of genotyping errors, pedigree errors, and missing data on a wide range of techniques, with a focus on the role of single-nucleotide polymorphisms (SNPs). Half of our group used simulated data, and half of our group used data from the Collaborative Study on the Genetics of Alcoholism (COGA). The simulated data had no missing genotypes and no genotyping errors, so our group, as a whole, removed data and introduced artificial errors to study the robustness of various techniques. Our teams showed that genotyping errors are less detectable and may have a greater impact on SNPs than on microsatellites, but recently developed methods that account for genotyping errors help reduce false positives, and the assumptions of these methods appear to be supported by observations from repeated genotyping. The ability to detect linkage disequilibrium (LD) was also substantially reduced by missing data; this in turn could affect tagging SNPs chosen to generate haplotypes. In the COGA sample, genotyping measurements were repeated in three ways. First, full-genome screens were performed on three sets of markers: 328 microsatellites, 11,560 SNPs from the Affymetrix GeneChip Mapping 10 K Array marker set, and 4,720 SNPs from the Illumina Linkage III panel. Second, the entire Affymetrix marker set was typed on the same 184 individuals by two different laboratories. Finally, the Affymetrix and Illumina marker panels had 94 SNPs in common. Our teams showed that both SNPs and microsatellites can be readily used to identify pedigree errors, and that SNPs have fewer genotyping errors and a low inconsistency rate. However, a fairly high rate of no-calls, especially for the Affymetrix platform, suggests that the inconsistency rate may be higher than observed. Genet. Epidemiol. 29(Suppl. 1):S120–S124, 2005. r 2005 Wiley-Liss, Inc.
Chandra Observations of the Bursting X-Ray Transient SAX J1747.0–2853 during Low-Level Accretion Activity

We present Chandra/ACIS observations of the bursting X-ray transient SAX J1747.0-2853 performed on 2001 July 18. We detected a bright source at the position of R.A. = 17h47m0260 and decl. = -28°52'589 (J2000.0, with a 1 σ error of ~07), consistent with the BeppoSAX and ASCA positions of SAX J1747.0-2853 and with the Ariel V position of the transient GX +0.2-0.2, which was active during the 1970s. The 0.5-10 keV luminosity of the source during our observations was ~ 3 × 1035 ergs s-1 (assuming a distance of 9 kpc), demonstrating that the source was in a low-level accretion state. We also report on the long-term light curve of the source as observed with the all-sky monitor on board the Rossi X-Ray Timing Explorer. After the initial 1998 outburst, two more outbursts (in 2000 and 2001) were detected with peak luminosities about 2 orders of magnitude larger than our Chandra luminosity. Our Chandra observation falls between those two outbursts, making the outburst history for SAX J1747.0-2853 complex. Those bright 2000 and 2001 outbursts, combined with the likely extended period of low-level activity between those outbursts, strongly suggest that the classification of SAX J1747.0-2853 as a faint X-ray transient was premature. It might be possible that the other faint X-ray transients can also exhibit bright, extended outbursts that would eliminate the need for a separate subclass of X-ray transients. We discuss our results also in the context of the behavior of X-ray binaries accreting at low levels with luminosities around 1035 ergs s-1, a poorly studied accretion rate regime.
Predicting genetic regulatory response using classification: yeast stress response

We present a novel classification-based algorithm called GeneClass for learning to predict gene regulatory response. Our approach is motivated by the hypothesis that in simple organisms such as Saccharomyces cerevisiae, we can learn a decision rule for predicting whether a gene is up- or down-regulated in a particular experiment based on (1) the presence of binding site subsequences (“motifs”) in the gene's regulatory region and (2) the expression levels of regulators such as transcription factors in the experiment (“parents”). Thus our learning task integrates two qualitatively different data sources: genome-wide cDNA microarray data across multiple perturbation and mutant experiments along with motif profile data from regulatory sequences. Rather than focusing on the regression task of predicting real-valued gene expression measurements, GeneClass performs the classification task of predicting +1 and -1 labels, corresponding to up- and down-regulation beyond the levels of biological and measurement noise in microarray measurements. GeneClass uses the Adaboost learning algorithm with a margin-based generalization of decision trees called alternating decision trees. In computational experiments based on the Gasch S. cerevisiae dataset, we show that the GeneClass method predicts up- and down-regulation on held-out experiments with high accuracy. We explore a range of experimental setups related to environmental stress response, and we retrieve important regulators, binding site motifs, and relationships between regulators and binding sites that are known to be associated to specific stress response pathways. Our method thus provides predictive hypotheses, suggests biological experiments, and provides interpretable insight into the structure of genetic regulatory networks. Supplementary website: http://www.cs.columbia.edu/compbio/geneclass
Useful signals from motor cortex

Historically, the motor cortical function has been explained as a funnel to muscle activation. This invokes the idea that motor cortical neurons, or ‘upper motoneurons’, directly cause muscle contraction just like spinal motoneurons. Thus, the motor cortex and muscle activity are inextricably entwined like a puppet master and his marionette. Recently, this concept has been challenged by current experimentation showing that many behavioural aspects of action are represented in motor cortical activity. Although this activity may still be related to muscle activation, the relation between the two is likely to be indirect and complex, whereas the relation between cortical activity and kinematic parameters is simple and robust. These findings show how to extract useful signals that help explain the underlying process that generates behaviour and to harness these signals for potentially therapeutic applications.
Estimating shoulder maximum muscle forces in individuals with C5-C6 tetraplegia

Individuals with spinal cord injury (SCI) at the C5-C6 level, lose voluntary control over some of the shoulder muscles, preventing them from performing activities such as transfers or reaching above horizontal. Rehabilitation interventions such as functional neuromuscular stimulation can be used to restore lost function in this population, but due to the mechanical complexity of the shoulder, implementing such interventions is a difficult task. Musculoskeletal modeling can be used to gain a better understanding of shoulder function following cervical SCI and to aid in the design of rehabilitation interventions that restore lost function. Following spinal cord injury, some muscles will become completely paralyzed and the strength of the muscles remaining under partial voluntary control will vary across subjects depending on the level and extent of the injury. In order to reflect SCI, the musculoskeletal model needs to be customized for each individual, specifically to include maximum muscle forces. An algorithm to estimate shoulder maximum muscle forces based on experimental measurements of shoulder moments and muscle activation has been developed and applied to simulated trial data. The algorithm could successfully retrieve the maximum muscle forces from the simulated data. The effect of practical issues such as the difficulty of measuring muscle activity in deeper muscles was also evaluated.
Reducing the probability of capture into resonance

A migrating planet can capture planetesimals into mean motion resonances. However, resonant trapping can be prevented when the drift or migration rate is sufficiently high. Using a simple Hamiltonian system for first and second order resonances, we explore how the capture probability depends on the order of the resonance, drift rate and initial particle eccentricity. We present scaling factors as a function of the planet mass and resonance strength to estimate the planetary migration rate above which the capture probability drops to less than 1/2. Applying our framework to multiple extra solar planetary systems that have two planets locked in resonance, we estimate lower limits for the outer planet’s migration rate allowing resonance capture of the inner planet. Mean motion resonances are comprised of multiple resonant subterms. We find that the corotation subterm can reduce the probability of capture when the planet eccentricity is above a critical value. We present factors that can be used to estimate this critical planet eccentricity. Applying our framework to the migration of Neptune, we find that Neptune’s eccentricity is near the critical value that would make its 2:1 resonance fail to capture twotinos. The capture probability is affected by the separation between resonant subterms and so is also a function of the precession rates of the longitudes of periapse of both planet and particle near resonance. Subject headings: celestial mechanics
Enantioselective synthesis of (−)-idiospermuline

Abstract The enantioselective total synthesis of the nonacyclic polypyrrolidinoindoline (−)-idiospermuline is described. Stereocontrolled formation of the vicinal quaternary carbon centers is achieved in a single step by dialkylation of an unsymmetrical prostereogenic dienolate with a tartrate-derived chiral dielectrophile. A catalyst-controlled diastereoselective Heck cyclization is employed to form the diaryl-substituted quaternary center.
Synthesis and biological activity of naturally occurring α-glucosidase inhibitors

Covering: 2005 to the end of 2009 In addition to their clinical importance in the treatment of type II diabetes, α-glucosidase inhibitors have attracted considerable attention from the synthetic community because of their profound effect on an array of cellular processes, including N-linked glycoprotein processing and maturation, oligosaccharide metabolism, and cell–cell and cell–virus recognition. Over the past decade, a number of structurally novel naturally occurring α-glucosidase inhibitors which do not conform to the classical iminosugar mold have been identified, including zwitterionic thiosugars and marine organosulfates. While these natural products are important leads in the development of new classes of glucosidase inhibitors, they have also attracted considerable attention as synthetic targets in of themselves. This article reviews the recent literature concerning the synthesis of these emerging natural product families, as well as the preparation of those polyhydroxylated alkaloids more traditionally associated with anti-α-glucosidase activity. 176 references are cited.
Analytical solution of a new class of integral equations

Let (1)Rh = f ,0 • xL, Rh = R L 0 R(x;y)h(y)dy, where the kernel R(x;y) satisfles the equation QR = P-(xiy). Here, Q and P are formal difierential operators of order n and m 0, m‚ 0, Qu := qn(x)u (n) + P ni1 j=0 qj(x)u (j) , Ph := h (m) + P mi1 j=0 pj(x)h (j) , q n(x) ‚ c> 0, the coe-cientsqj(x) andpj(x) are smooth functions deflned onR,-(x) is the delta-function, f 2 H fi (0;L), fi := nim 2 , H fi is the Sobolev space. An
A 4+3 cycloaddition approach to the spatane ring system

Abstract The adduct of dichloroketene and cyclopentene was converted to a tricyclo[5.3.0.0 2,6 ]decane ring system using a 4+3 cycloaddition reaction followed by a quasi-Favorskii rearrangement as the key steps.
Using multiple samples to learn mixture models

In the mixture models problem it is assumed that there are K distributions θ1,..., θK and one gets to observe a sample from a mixture of these distributions with unknown coefficients. The goal is to associate instances with their generating distributions, or to identify the parameters of the hidden distributions. In this work we make the assumption that we have access to several samples drawn from the same K underlying distributions, but with different mixing weights. As with topic modeling, having multiple samples is often a reasonable assumption. Instead of pooling the data into one sample, we prove that it is possible to use the differences between the samples to better recover the underlying structure. We present algorithms that recover the underlying structure under milder assumptions than the current state of art when either the dimensionality or the separation is high. The methods, when applied to topic modeling, allow generalization to words not present in the training data.
Random Expected Utility

We develop and analyze a model of random choice and random expected utility. A decision problem is a finite set of lotteries that describe the feasible choices. A random choice rule associates with each decision problem a probability measure over choices. A random utility function is a probability measure over von Neumann-Morgenstern utility functions. We show that a random choice rule maximizes some random utility function if and only if it is mixture continuous, monotone (the probability that a lottery is chosen does not increase when other lotteries are added to the decision problem), extreme (lotteries that are not extreme points of the decision problem are chosen with probability 0), and linear (satisfies the independence axiom).
Human Capital and Economic Activity in Urban America

Abel J. R. and Gabe T. M. Human capital and economic activity in urban America, Regional Studies. The relationship between human capital and economic activity in US metropolitan areas is examined, extending the literature in two ways. First, new data on metropolitan area gross domestic product are utilized to measure economic activity. Results show that a 1 percentage point increase in the proportion of residents with a college degree is associated with about a 2% increase in metropolitan area gross domestic product per capita. Second, measures of human capital are developed that reflect the types of knowledge within US metropolitan areas. Regional knowledge stocks related to the provision of producer services and information technology are important determinants of economic vitality. Abel J. R. et Gabe T. M. Le capital humain et l'activite economique dans l'Amerique urbaine, Regional Studies. On examine le rapport entre le capital humain et l'activite economique dans les zones metropolitaines aux Etats-U...
Evaluating the Impact of Data Quality on Sampling

Learning from imbalanced training data can be a difficult endeavour, and the task is made even more challenging if the data is of low quality or the size of the training dataset is small. Data sampling is a commonly used method for improving learner performance when data is imbalanced. However, little effort has been put forth to investigate the performance of data sampling techniques when data is both noisy and imbalanced. In this work, we present a comprehensive empirical investigation of the impact of changes in four training dataset characteristics — dataset size, class distribution, noise level and noise distribution — on data sampling techniques. We present the performance of four common data sampling techniques using 11 learning algorithms. The results, which are based on an extensive suite of experiments for which over 15 million models were trained and evaluated, show that: (1) even for relatively clean datasets, class imbalance can still hurt learner performance, (2) data sampling, however, may not improve performance for relatively clean but imbalanced datasets, (3) data sampling can be very effective at dealing with the combined problems of noise and imbalance, (4) both the level and distribution of class noise among the classes are important, as either factor alone does not cause a significant impact, (5) when sampling does improve the learners (i.e. for noisy and imbalanced datasets), RUS and SMOTE are the most effective at improving the AUC, while SMOTE performed well relative to the F-measure, (6) there are significant differences in the empirical results depending on the performance measure used, and hence it is important to consider multiple metrics in this type of analysis, and (7) data sampling rarely hurt the AUC, but only significantly improved performance when data was at least moderately skewed or noisy, while for the F-measure, data sampling often resulted in significantly worse performance when applied to slightly skewed or noisy datasets, but did improve performance when data was either severely noisy or skewed, or contained moderate levels of both noise and imbalance.
Gender Differences in Trust and Reciprocity

We use the investment game introduced by Berg, Dickhaut and McCabe (1995) to explore gender differences in trust and reciprocity. In doing so we replicate and extend the results first reported by Croson and Buchan (1999). We find that men exhibit greater trust than women do while women show higher levels of reciprocity. Trusting behavior is driven strongly by expectations of reciprocation. We posit that the lower levels of trust exhibited by women may be attributed to a higher degree of risk aversion.
Relations between Distorted and Original Angles in STR

Using the Oblique-Length Contraction Factor, which is a generalization of Lorentz Contraction Factor, one shows several trigonometric relations between distorted and original angles of a moving object lengths in the Special Theory of Relativity.
The Effect of a Pulsed Interference Signal on an Adaptive Array

The performance of a least mean square (LMS) adaptive array in the presence of a pulsed interference signal is examined. It is shown that a pulsed interference signal has two effects. First, it causes the array to modulate the desired signal envelope (but not its phase). Second, it causes the array output signal-to-interferenceplus-noise ratio (SINR) to vary with time. The desired signal modulation is evaluated as a function of signal arrival angles, powers and interference pulse-repetition frequency (PRF) and pulsewidth. It is shown that the signal modulation is small except when the interference arrives close to the desired signal. To evaluate the effect of the time-varying SINR, it is assumed that the array is used in a differential phase-shift keyed (DPSK) communication system. It is shown that the SINR variation causes a noticeable but not disastrous increase in the bit error probability.
Dynamical systems method for solving nonlinear equations with monotone operators

A version of the Dynamical Systems Method (DSM) for solving ill-posed nonlinear equations with monotone operators in a Hilbert space is studied in this paper. An a posteriori stopping rule, based on a discrepancy-type principle is proposed and justified mathematically. The results of two numerical experiments are presented. They show that the proposed version of DSM is numerically efficient. The numerical experiments consist of solving nonlinear integral equations.
Native Internal Migration and the Labor Market Impact of Immigration

This paper presents a theoretical and empirical study of how immigration influences the joint determination of the wage structure and internal migration behavior for native-born workers in local labor markets. Using data from the 1960-2000 decennial censuses, the study shows that immigration is associated with lower in-migration rates, higher out-migration rates, and a decline in the growth rate of the native workforce. The native migration response attenuates the measured impact of immigration on wages in a local labor market by 40 to 60 per cent, depending on whether the labor market is defined at the state or metropolitan area level.
The optimal single forest rotation under climatic fluctuation effect

The stochastic impact of the "climatic fluctuation effect" is introduced in the traditional determinant timber growth model and optimal harvesting strategies are derived under different stochastic "climatic fluctuation effect" patterns. Results show that properties of different patterns significantly affect the forms of the optimal harvesting rules.
Plasma reflectors for electronic beam steering in radar systems

The author describes investigations into methods of generating a planar plasma for use as a reflector for radar waves. The use of the plasma reflector could allow electronic beam steering at frequencies above what is generally viable for phased arrays. Three aspects of the planar plasma production are investigated: localization of the plasma, main plasma production, and long-term viability of the system. Possible applications include ship-based antennas at X-band, airborne antennas at 94 GHz, and space-based antennas at 60 GHz. The author discusses system considerations for the three potential radar configurations. Results and potential small-scale experiments to test various aspects of the concept are discussed. >
Wildlife Conservation Payments to Address Habitat Fragmentation and Disease Risks

We develop a bioeconomic model to gain insight into the challenges of Payments for Environmental Services (PES) as applied to protect endangered species given wildlife-livestock disease risks and habitat fragmentation. We show how greater connectivity of habitat creates an endogenous trade-off. More connectedness both (i) ups the chance that populations of endangered species will grow more rapidly, while (ii) simultaneously increasing the likelihood diseases will spread more quickly. We examine subsidies for habitat connectedness, livestock vaccination, and reduced movement of infected livestock. We find the cost-effective policy is to first subsidize habitat connectivity rather than vaccinations – this serves to increase habitat contiguousness. Once habitat is sufficiently connected, disease risks increase to a level to make disease-related subsidies worthwhile. Highly connected habitat requires nearly all the government budget be devoted to disease prevention and control. The result of the conservation payments is significantly increased wildlife abundance, increased livestock health and abundance, and increased development opportunities.
Policy Signals and Executive Governance: Presidential Rhetoric in the War on Drugs

One consequence of the president's use of rhetoric to shape the public agenda, the media, and congressional attention is less recognized: Presidential rhetoric shapes the priorities of the administrative agents over whom he seeks managerial control. We present statistical tests of the managerial power of presidential policy signals in the case of the United States Attorneys' implementation of the federal “War on Drugs.” We find that presidential policy signals shifted the composition of the Attorneys' caseload, although not to the exclusion of other pertinent local, national, and internal factors. Yet, the consequences of presidential rhetoric for executive governance remain real and substantial.
A Word-to-Word Model of Translational Equivalence

Many multilingual NLP applications need to translate words between different languages, but cannot afford the computational expenses of inducing or applying a full translation model. For theses applications, we have designed a fast algorithm for estimating a partial translation model, which accounts for translational equivalence only at the word level. The model's precision/recall trade-off can be directly controlled via one threshold parameter. This feature makes the model more suitable for applications that are not fully statistical. The model's hidden parameters can be easily conditioned on information extrinsic to the model, providing an easy way to integrate pre-existing knowledge such as part-of-speech, dictionaries, word order, etc., Our model can link word tokens in parallel texts as well as other translation models in the literature. Unlike other translation models, it can automatically produce dictionary-sized translation lexicons, and it can do so with over 99% accuracy.
Laboratory Simulation of a Deep Ocean In-Situ Heat Transfer Experiment

The Subseabed Disposal Program has recently completed a 30-day, 0.286-scale laboratory simulation of an In Situ Heat Transfer Experiment (ISHTE), scheduled for eventual deployment in the deep ocean 600 nautical miles north of Hawaii.
Stereoselective hydrogenations of aryl-substituted dienes

The carbene complex 1 can mediate hydrogenations of dienes with up to 20∶1.0 diastereoselectivity and 99% ee; the scope and limitations of these reactions were investigated.