cssi/SciSciGPT-SciSciNet huggingface dataset:
Facilitating Adoption of Internet Technologies and Services with Externalities via Cost Subsidization

This article models the temporal adoption dynamics of an abstracted Internet technology or service, where the instantaneous net value of the service perceived by each (current or potential) user/customer incorporates three key features: (i) user service affinity heterogeneity, (ii) a network externality, and (iii) a subscription cost. Internet technologies and services with network externalities face a “chicken-and-egg” adoption problem in that the service requires an established customer base to attract new customers. In this article, we study cost subsidization as a means to “reach the knee,” at which point the externality drives rapid service adoption, and thereby change the equilibrium service fractional adoption level from an initial near-zero level to a final near-one level (full adoption). We present three simple subsidy models and evaluate them under two natural performance metrics: (i) the duration required for the subsidized service to reach a given target adoption level and (ii) the aggregate cost of the subsidy born by the service provide. First, we present a “two-target adoption subsidy” that subsidizes the cost to keep the fraction of users with positive net utility at a (constant) target level until the actual adoption target is reached. Second, we study a special case of the above where the target ensures all users have positive net utility, corresponding to a “quickest adoption” subsidy (QAS). Third, we introduce an approximation of QAS that only requires the service provider adjust the subsidy level a prescribed number of times. Fourth, we study equilibria and their stability under uniformly and normally distributed user service affinities, highlighting the unstable equilibrium in each case as the natural target adoption level for the provider. Finally, we provide a fictional case study to illustrate the application of the results in a (hopefully) realistic scenario, along with a brief discussion of the limitations of the model and analysis.
The Advantages of Probabilistic Survey Questions

In monetary policymaking, central bankers have long pointed out the importance of measuring the expectations of financial market participants, households, and firms —especially with regard to inflation and the central bank’s so-called “reaction function” to changes in the economic outlook. In addition to model- and market-implied measures, there has been a growing interest in and reliance on survey-based measures of subjective expectations. This article describes two major innovative survey initiatives conducted by the New York Fed to measure policy-relevant expectations of households and market participants: the Survey of Consumer Expectations, and the Survey of Primary Dealers and Survey of Market Participants. A key feature of these surveys is its use of a probabilistic question format to elicit the likelihood respondents assign to different future events. We discuss the advantages of using probabilistic questions, illustrate their value in more fully measuring beliefs and uncertainty, and document the pervasiveness and importance of heterogeneity in beliefs among our survey respondents.
The expressive power of voting polynomials

We consider the problem of approximating a Boolean functionf∶{0,1} n →{0,1} by the sign of an integer polynomialp of degreek. For us, a polynomialp(x) predicts the value off(x) if, wheneverp(x)≥0,f(x)=1, and wheneverp(x)<0,f(x)=0. A low-degree polynomialp is a good approximator forf if it predictsf at almost all points. Given a positive integerk, and a Boolean functionf, we ask, “how good is the best degreek approximation tof?” We introduce a new lower bound technique which applies to any Boolean function. We show that the lower bound technique yields tight bounds in the casef is parity. Minsky and Papert [10] proved that a perceptron cannot compute parity; our bounds indicate exactly how well a perceptron canapproximate it. As a consequence, we are able to give the first correct proof that, for a random oracleA, PP A is properly contained in PSPACE A . We are also able to prove the old AC0 exponential-size lower bounds in a new way. This allows us to prove the new result that an AC0 circuit with one majority gate cannot approximate parity. Our proof depends only on basic properties of integer polynomials.
EFFECTIVENESS OF THE GROUND-BASED TRANSCEIVER (GBT) PARROT SYSTEM FOR MONITORING GPS INTEGRITY FOR ALASKA ATC 'RADAR-LIKE SERVICES' USING ADS-B

In January of 2001, the Federal Aviation Administration (FAA) commissioned the first use of Automatic Dependent Surveillance Broadcast (ADS-B) based on the Global Positioning System (GPS) to suppor...
Pricing and capacity planning for product-line expansion and reduction

We investigate optimal pricing and capacity planning decisions for product-line settings such as introducing a new product or dropping an existing one. We consider a two-product, two-period model with stochastic demands, where price and capacity decisions are made at the outset. Investment in capacity must be traded-off against the possibility of buying at higher spot market prices due to shortage in capacity or charging a higher price to manage the demand. Prior studies argue that introducing an additional product to the product-line strains capacity, resulting in an increase in the price of an existing product. In contrast, we find that introducing a new product can also result in a drop in price of an existing product, enabling strategic pricing by firms. The necessary condition for this to occur is that the demand uncertainties for the products are of similar magnitude and negatively correlated. Similar insights are obtained for the setting where an existing product is dropped from the product-line. H...
Financial Frictions and the Great Productivity Slowdown

We study the role of financial frictions for productivity. Using a rich cross-country firm-level data, we exploit variation in preexisting exposure to the 2008 global financial crisis to study the post-crisis productivity slowdown. Firms with weaker precrisis balance sheets experienced a highly persistent decline in post-crisis total factor productivity growth relative to their less vulnerable counterparts, accounting for about one-third of the within-firm productivity slowdown. This decline was larger for firms that faced a more severe tightening of credit conditions. Financially fragile firms cut back on innovation activities, one channel through which financial frictions weakened post-crisis productivity growth.
Earnings quality and short selling: Evidence from real earnings management in the United States

Prior research provides evidence consistent with managers using real earnings management (REM) to increase earnings. This study examines whether short sellers exploit the overvaluation of firms employing REM. I find that firms with more REM have higher subsequent short interest. The positive relation between REM and short interest is more pronounced in settings where the costs associated with accrual-based earnings management are high, such as when a firm has low accounting flexibility or faces greater scrutiny from a high quality auditor. I also find some evidence that short sellers respond to REM more than to other fundamental signals of firm overvaluation. My inferences are robust to the use of propensity score matching. Collectively, my evidence suggests that short sellers not only trade on REM information, but they also trade as if they understand the substitutive nature of alternative earnings management methods. This study provides additional insight into the important role that short sellers play in monitoring managerial operating decisions and overall earnings quality.
The Grecian horse: does immigration lead to the deterioration of American institutions?

Concerns about the institutional impact of immigration, particularly in the United States, are not new. We can trace them back to Benjamin Franklin, Thomas Jefferson, and Alexander Hamilton. More recently, in response to a literature that questions the desirability of current immigration restrictions, Borjas (J Econ Lit 53:961–974, 2015) speculates that immigrants coming from countries with poor institutions could reduce substantially the institutional quality in the United States to a point where it could negate all economic gains associated with immigration in terms of GDP and income. Using the Economic Freedom of North America index since 1980, we find no evidence to corroborate Borjas’s concerns. However, we find mixed evidence that immigration increases minimum wages and union density.
Memories with Josephson Junctions

The talk is based on an overview which was published recently (1). For this reason, only an abstract is given here, which includes Later results not contained in the aforementioned overview. The presently-known Josephson memory cells store information as persistent currents in superconducting loops, or what is equivalent as a magnetic flux in the area of the ring. This method of storage is nonvolatile and has no power consumption in the storing state. In a superconducting ring system, the magnetic flux is quantized, and cells have been built which operate either with only one flux quantum, or with many of them. For the Latter cells with many flux quanta (ring cells), quite a number of designs exist. They have one or two Josephson junctions in the ring, which allow writing. An external junction which is controlled by the ring current serves for non-destructive reading of the information. The smallest cell realized had an area of 900 ?m2 with a 2 ?m minimum line width. Switching speed was ? 80 ps. Cells which store information as a single-flux quantum (single flux-quantum cells = SFQ cells) in the ring, usually contain two Josephson junctions used for reading and writing. Read-out in most of these cells is destructive, but methods of reading non-destructively have also been proposed. The smallest device made had an area of ? 150 ?m2 with a minimum line width of 2 ?m. The read signal had a rise time ? 100 ps.
SERUM ALBUMIN PREDICTS SURVIVAL AND POST-OPERATIVE COURSE FOLLOWING SURGERY FOR GERIATRIC HIP FRACTURE

Malnutrition is a potentially modifiable risk factor that may contribute to complications following geriatric hip fracture surgery. The purpose of this study was to investigate the association between preoperative hypoalbuminemia, a marker for malnutrition, and complications during the thirty days following surgery for geriatric hip fracture. The American College of Surgeons National Surgical Quality Improvement Program was used to conduct a retrospective cohort study of geriatric patients (>65 years) undergoing surgery for hip fracture. Patients without preoperative serum albumin concentration were excluded. Outcomes were compared between patients with and without hypoalbuminemia (defined as serum albumin concentration 17,651 Patients were identified. Of these, 8,272 (46.9%) underwent hemiarthroplasty, 759 (4.3%) total joint arthroplasty, 324 (1.9%) percutaneous fixation, 2,445 (13.9%) plate/screw fixation, and 5,833 (33.1%) intramedullary fixation. The prevalence of hypoalbuminemia was 45.9% (Figure 1). The risk for death was strongly associated with serum albumin concentration, with a linear increase in risk observed as albumin fell below 3.5 g/dL (p The present study suggests that hypoalbuminemia is a powerful independent risk factor for death following surgery for geriatric hip fracture. This association persists over-and-above any associations of death with age, sex, body mass index, and comorbidities. Based on these data, we propose that the nutritional status of hip fracture patients should receive greater attention, and that randomized trials testing for efficacy of aggressive postoperative nutritional interventions may be warranted. For any figures or tables, please contact the authors directly by clicking on ‘Info & Metrics’ above to access author contact details.
Trust is heritable, whereas distrust is not

Why do people distrust others in social exchange? To what degree, if at all, is distrust subject to genetic influences, and thus possibly heritable, and to what degree is it nurtured by families and immediate peers who encourage young people to be vigilant and suspicious of others? Answering these questions could provide fundamental clues about the sources of individual differences in the disposition to distrust, including how they may differ from the sources of individual differences in the disposition to trust. In this article, we report the results of a study of monozygotic and dizygotic female twins who were asked to decide either how much of a counterpart player's monetary endowment they wanted to take from their counterpart (i.e., distrust) or how much of their own monetary endowment they wanted to send to their counterpart (i.e., trust). Our results demonstrate that although the disposition to trust is explained to some extent by heritability but not by shared socialization, the disposition to distrust is explained by shared socialization but not by heritability. The sources of distrust are therefore distinct from the sources of trust in many ways.
Survival of Infants With Spina Bifida—Atlanta, 1972–1979

• We studied the survival of a population-based cohort of 154 infants with spina bifida who were born during the eight-year period from 1972 through 1979 to residents of Atlanta. Our objectives were to describe the cohort's survival experience and to explore relationships between clinical characteristics and survival. Overall, 57% of the cohort survived one year or more. This figure is misleading, however, because it conceals important differences in survival among subgroups of affected infants. From univariate analyses, we observed significant differences in survival among infants categorized by year of birth, birth weight, the open-closed status of the defect, the highest level of the defect on the spine, the presence of multiple major birth defects, and the presence of hydrocephalus at birth. More infants born in the late 1970s survived their first year of life than infants born in the early 1970s; infants with open defects had lower survival than those with closed defects; and infants whose defects were low on the spine had better survival than those whose defects were higher. When comparing the survival experience of this cohort with that of other groups from other areas or from more recent years, health workers must consider referral biases and differences in the distribution of clinical characteristics. ( AJDC 1985;139:518-523)
Adaptive path tracking control of robotic manipulators with unknown payload dynamics

Abstract In practical applications, robots are often required to handle payloads with unknown dynamics. This paper considers the path tracking control problem of a robot carrying an unknown payload. An adaptive control scheme is presented in which the uncertain dynamics of the payload is taken into account, and prior information about the payload's mass or inertia is not required. By introducing a generalized inner product, an alternative approach for stability analysis (rather than the more usual Lyapunov method) is established which proves the asymptotically stable control of the proposed strategy.
Use of Biofeedback in Treatment of Fecal Incontinence in Patients With Meningomyelocele

Fourteen children (aged 5 to 17 years) with meningomyelocele and significant fecal soiling underwent anorectal manometry using a three-balloon system connected to a physiograph. On the basis of manometric criteria demonstrating some rectal sensation, eight patients were treated with biofeedback conditioning. Patients were taught to contract the external anal sphincter or nearby gluteal muscles in response to various volumes of rectal distention. Four of the eight patients who were treated with biofeedback had a good clinical response with disappearance of soiling or a greater than 75% improvement in the frequency of soiling. Follow-up periods ranged from three to 12 months. The minimum criteria for successful treatment appeared to be normal threshold of rectal sensation and ability to contract gluteal or related muscles. Anorectal manometry is a rapid, easily obtained test that can identify those children with meningomyelocele and fecal incontinence who may benefit from biofeedback conditioning. Biofeedback is a simple, safe, and effective technique in the treatment of certain children with fecal soiling due to neurogenic anal sphincter dysfunction.
Genetics of paediatric cardiomyopathies.

Purpose of reviewPaediatric cardiomyopathy is a rare disease with a genetic basis. The purpose of this review is to discuss the current status of genetic findings in the paediatric cardiomyopathy population and present recent progress in utilizing this information for management and therapy.Recent f
Decentralizing Pork: Congressional Roll‐Call Voting, Decentralized Administration, and Distributive Politics

Congress packages pork‐barrel spending in complicated proposals that belie theories of distributive politics. We theorize that roll‐call voting on such bills depends on grant programs' administrative centralization, party ties with presidents or home‐state governors, and differences in geographic representation between chambers. Analyzing votes between 1973 and 2010 using a within‐legislator strategy reveals that House members are less likely to support decentralized spending when they are copartisans with presidents, while senators support decentralization regardless of such party ties. When House members or senators share affiliation with only governors or with neither chief executive, the likelihood of support rises with decentralization. Supporting Information
Velocity force curves, laning, and jamming for oppositely driven disk systems

Using simulations we examine a two-dimensional disk system in which two disk species are driven in opposite directions. We measure the average velocity of one of the species versus the applied driving force and identify four phases as function of drive and disk density: a jammed state, a completely phase separated state, a continuously mixing phase, and a laning phase. The transitions between these phases are correlated with jumps in the velocity–force curves that are similar to the behavior observed at dynamical phase transitions in driven particle systems with quenched disorder such as vortices in type-II superconductors. In some cases the transitions between phases are associated with negative differential mobility in which the average absolute velocity of either species decreases with increasing drive. We also consider the situation where the drive is applied to only one species as well as systems in which both species are driven in the same direction with different drive amplitudes. We show that the phases are robust against the addition of thermal fluctuations. Finally, we discuss how the transitions we observe could be related to absorbing phase transitions where a system in a phase separated or laning regime organizes to a state in which contacts between the disks no longer occur and dynamical fluctuations are lost.
The propagation and backscattering of soliton-like pulses in a chain of quartz beads and related problems. (II). Backscattering

We demonstrate that the propagation of solitons, soliton-like excitations and acoustic pulses discussed in the preceding article (M. Manciu, S. Sen and A.J. Hurd, Physica A, preceding article) can be used to detect buried impurities in a chain of elastic grains with Hertzian contacts. We also present preliminary data for 3D granular beds, where soliton-like objects can form and can be used to probe for buried impurities, thus suggesting that soliton-pulse spectroscopy has the potential to become a valuable tool for probing the structural properties of granular assemblies. The eects of restitution are briey discussed. We refer to available experiments which support our contention. c 1999 Elsevier Science B.V. All rights reserved.
The 4/3 Additive Spanner Exponent Is Tight

A spanner is a sparse subgraph that approximately preserves the pairwise distances of the original graph. It is well known that there is a smooth tradeoff between the sparsity of a spanner and the quality of its approximation, so long as distance error is measured multiplicatively. A central open question in the field is to prove or disprove whether such a tradeoff exists also in the regime of additive error. That is, is it true that for all v > 0, there is a constant kv such that every graph has a spanner on O(n1+v) edges that preserves its pairwise distances up to +kv? Previous lower bounds are consistent with a positive resolution to this question, while previous upper bounds exhibit the beginning of a tradeoff curve: All graphs have +2 spanners on O(n3/2) edges, +4 spanners on O(n7/5) edges, and +6 spanners on O(n4/3) edges. However, progress has mysteriously halted at the n4/3 bound, and despite significant effort from the community, the question has remained open for all 0
Minimal Clinically Important Difference for the Rasch Neuropsychiatric Inventory Irritability and Aggression Scale for Traumatic Brain Injury.

Abstract Objective To determine the minimal clinically important difference (MCID) for a Rasch measure derived from the Irritability/Lability and Agitation/Aggression subscales of the Neuropsychiatric Inventory (NPI)—the Rasch NPI Irritability and Aggression Scale for Traumatic Brain Injury (NPI-TBI-IA). Design Distribution-based statistical methods were applied to retrospective data to determine candidates for the MCID. These candidates were evaluated by anchoring the NPI-TBI-IA to Global Impression of Change (GIC) ratings by participants, significant others, and a supervising physician. Setting Postacute rehabilitation outpatient clinic. Participants 274 cases with observer ratings; 232 cases with self-ratings by participants with moderate-severe TBI at least 6 months postinjury. Interventions Not applicable. Main Outcome Measure NPI-TBI-IA. Results For observer ratings on the NPI-TBI-IA, anchored comparisons found an improvement of 0.5 SD was associated with at least minimal general improvement on GIC by a significant majority (69%–80%); 0.5 SD improvement on participant NPI-TBI-IA self-ratings was also associated with at least minimal improvement on the GIC by a substantial majority (77%–83%). The percentage indicating significant global improvement did not increase markedly on most ratings at higher levels of improvement on the NPI-TBI-IA. Conclusions A 0.5 SD improvement on the NPI-TBI-IA indicates the MCID for both observer and participant ratings on this measure.
Assessing bimanual motor skills with optical neuroimaging

Measuring motor skill proficiency is critical for the certification of highly skilled individuals in numerous fields. However, conventional measures use subjective metrics that often cannot distinguish between expertise levels. We present an advanced optical neuroimaging methodology that can objectively and successfully classify subjects with different expertise levels associated with bimanual motor dexterity. The methodology was tested by assessing laparoscopic surgery skills within the framework of the fundamentals of a laparoscopic surgery program, which is a prerequisite for certification in general surgery. We demonstrate that optical-based metrics outperformed current metrics for surgical certification in classifying subjects with varying surgical expertise. Moreover, we report that optical neuroimaging allows for the successful classification of subjects during the acquisition of these skills.
Evidence for accretion of fine-grained rims in a turbulent nebula for CM Murchison

Abstract We use X-ray computed tomography (XCT) to examine the 3D morphology and spatial relationship of fine-grained rims (FGRs) of Type I chondrules in the CM carbonaceous chondrite Murchison to investigate the formation setting (nebular vs. parent body) of the FGRs. We quantify the sizes, shapes, and orientations of the chondrules and FGRs and develop a new algorithm to examine the 3D variation of FGR thickness around each chondrule. We find that the average proportion of chondrule volume contained in the rim for Murchison chondrules is 35.9%. The FGR volume in relation to the interior chondrule radius is well described by a power law function as proposed for accretion of FGRs in a weakly turbulent nebula by Cuzzi (2004) . The power law exponent indicates that the rimmed chondrules behaved as Stokes number S t η > 1 nebular particles in Kolmogorov η scale turbulence. FGR composition as inferred from XCT number appears essentially uniform across interior chondrule types and compositions, making formation by chondrule alteration unlikely. We determine that the FGRs were compressed by the impact event(s) that deformed Murchison ( Hanna et al., 2015 ), resulting in rims that are thicker in the plane of foliation but that still preserve their nebular morphological signature. Finally, we propose that the irregular shape of some chondrules in Murchison is a primary feature resulting from chondrule formation and that chondrules with a high degree of surface roughness accreted a relatively larger amount of nebular dust compared to smoother chondrules.
Strategic Commitment to a Production Schedule with Uncertain Supply and Demand: Renewable Energy in Day-Ahead Electricity Markets

We consider a day-ahead electricity market that consists of multiple competing renewable firms (e.g., wind generators) and conventional firms (e.g., coal-fired power plants) in a discrete-time setting. The market is run in every period, and all firms submit their price-contingent production schedules in every day-ahead market. Following the clearance of a day-ahead market, in the next period, each (renewable) firm chooses its production quantity (after observing its available supply). If a firm produces less than its cleared day-ahead commitment, the firm pays an undersupply penalty in proportion to its underproduction. We explicitly characterize firms’ equilibrium strategies by introducing and analyzing a supply function competition model. The purpose of an undersupply penalty is to improve reliability by motivating each firm to commit to quantities it can produce in the following day. We prove that in equilibrium, imposing or increasing a market-based undersupply penalty rate in a period can result in a...
Women’s welfare and livelihoods outside of marriage: evidence from rural Tanzania

This paper explores the welfare and livelihood strategies of women in rural Tanzania after they exit marriage. We draw from a three-wave individual-level longitudinal survey, using a correlated random effects approach within regression analysis to control for time-invariant individual effects. Attention is given to whether women exit marriage through widowhood or divorce, and whether they subsequently become household heads or join another household. Nearly 40% of widowed or divorced women are not the heads of their households, but instead reside with relatives. We find that women, and particularly widows, are more likely to be poor after marriage exit. Upon widowhood or divorce, women also work longer hours in off-farm employment, and those who become household heads are especially likely to experience a reduction in land access and a heightened reliance on non-farm income, including the receipt of transfers. This underscores the importance of both the non-farm economy and family networks for women’s livelihoods after marriage. Results illustrate that women’s experiences outside of marriage are diverse and cannot be broadly proxied with a household status of being female-headed.
Structural Complementation of the Catalytic Domain of Pseudomonas Exotoxin A

Pseudomonas exotoxin A (PE3) is a specific ADP-ribosyltransferase for eukaryotic elongation factor 2 (eEF2). ADP-ribosylation of eEF2 arrests ribosomal protein synthesis and potently induces cell death by apoptosis. A single molecule of functional homologs of exotoxin A, such as Diphtheria toxin, is known to be sufficient to kill a cell. We have designed and characterized catalytically inactive fragments of PE3 that are capable of structural complementation. We dissected PE3 at an extended loop and fused each fragment to one subunit of a heterospecific coiled coil.In vitro ADP-ribosylation and protein translation assays demonstrate that the resulting fusions - supplied exogenously as genetic elements or purified protein fragments - had no significant catalytic activity or effect on protein synthesis individually, but in combination catalyzed the ADP-ribosylation of eEF2 and inhibited protein synthesis. Although complementing PE3 fragments are less efficient catalytically than intact PE3 in cell-free systems, co-expression in live cells transfected with transgenes encoding the toxin fusions inhibits protein synthesis and causes cell death comparably as intact PE3. Split PE3 offers a direct extension of the immunotoxin approach to generate bispecific agents that may be useful to target complex phenotypes.View Large Image | View Hi-Res Image | Download PowerPoint Slide
Automatic cell segmentation by adaptive thresholding (ACSAT) for large-scale calcium imaging datasets

Advances in calcium imaging have made it possible to record from an increasingly larger number of neurons simultaneously. Neuroscientists can now routinely image hundreds to thousands of individual neurons. An emerging technical challenge that parallels the advancement in imaging a large number of individual neurons is the processing of correspondingly large datasets. One important step is the identification of individual neurons. Traditional methods rely mainly on manual or semimanual inspection, which cannot be scaled for processing large datasets. To address this challenge, we focused on developing an automated segmentation method, which we refer to as automated cell segmentation by adaptive thresholding (ACSAT). ACSAT works with a time-collapsed image and includes an iterative procedure that automatically calculates global and local threshold values during successive iterations based on the distribution of image pixel intensities. Thus, the algorithm is capable of handling variations in morphological details and in fluorescence intensities in different calcium imaging datasets. In this paper, we demonstrate the utility of ACSAT by testing it on 500 simulated datasets, two wide-field hippocampus datasets, a wide-field striatum dataset, a wide-field cell culture dataset, and a two-photon hippocampus dataset. For the simulated datasets with truth, ACSAT achieved >80% recall and precision when the signal-to-noise ratio was no less than ∼24 dB.
CRISPR, Patents, and the Public Health

Patent issues surrounding CRISPR, the revolutionary genetic editing technology, may have important implications for the public health. Patents maintain high prices for novel therapies, limiting patient access. Relatedly, insurance coverage for expensive therapies is waning. Patents also misallocate research and development resources to profitable disease indications rather than those that necessarily impinge on the public health. And it is unclear how CRISPR therapies will figure into the current regulatory framework for biosimilars. Policy makers and physicians should consider these issues now, before CRISPR therapies become widely adopted-and entrenched-in the marketplace.
Towards an accurate and efficient heuristic for species/gene tree co-estimation

Motivation Species and gene trees represent how species and individual loci within their genomes evolve from their most recent common ancestors. These trees are central to addressing several questions in biology relating to, among other issues, species conservation, trait evolution and gene function. Consequently, their accurate inference from genomic data is a major endeavor. One approach to their inference is to co-estimate species and gene trees from genome-wide data. Indeed, Bayesian methods based on this approach already exist. However, these methods are very slow, limiting their applicability to datasets with small numbers of taxa. The more commonly used approach is to first infer gene trees individually, and then use gene tree estimates to infer the species tree. Methods in this category rely significantly on the accuracy of the gene trees which is often not high when the dataset includes closely related species. Results In this work, we introduce a simple, yet effective, iterative method for co-estimating gene and species trees from sequence data of multiple, unlinked loci. In every iteration, the method estimates a species tree, uses it as a generative process to simulate a collection of gene trees, and then selects gene trees for the individual loci from among the simulated gene trees by making use of the sequence data. We demonstrate the accuracy and efficiency of our method on simulated as well as biological data, and compare them to those of existing competing methods. Availability and implementation The method has been implemented in PhyloNet, which is publicly available at http://bioinfocs.rice.edu/phylonet.
Trust and Disintermediation: Evidence from an Online Freelance Marketplace

As a platform improves trust between the two sides of its market to facilitate matching and transactions, it faces an increased risk of disintermediation: with sufficient trust, the two sides may c...
Combinatorial proof of an identity of Andrews and Yee

Recently, Andrews and Yee studied two-variable generalizations of two identities involving partition functions $$p_\omega (n)$$ and $$p_\nu (q)$$ introduced by Andrews, Dixit and Yee. In this paper, we present a combinatorial proof of an interesting identity in their work.
Pediatric vision screening: The Colorado school nurse experience

Colorado schools are required by law to perform vision screening. The aim of the study was to elucidate the vision screening process from the school nurse perspective. An electronic questionnaire distributed to Colorado school nurses, and developed by the author, was used to query Colorado nurses about the logistical challenges they face when performing vision screening. Common challenges faced when performing vision screening included: inadequate staff to perform vision screening, inadequate space to complete testing, uncooperative students, and poor parental compliance with referrals for further evaluation after their child failed their vision screen. Most nurses do not use instrument-based screening. Many nurses did not properly occlude the eyes when performing monocular visual acuity testing, which may lead to false negative screening results. The results of the questionnaire suggest there are opportunities to improve the vision screening process by nurses in Colorado schools.
Heterochromatin-Enriched Assemblies Reveal the Sequence and Organization of the Drosophila melanogaster Y Chromosome.

Heterochromatic regions of the genome are repeat-rich and poor in protein coding genes, and are therefore underrepresented in even the best genome assemblies. One of the most difficult regions of the genome to assemble are sex-limited chromosomes. The Drosophila melanogaster Y chromosome is entirely heterochromatic, yet has wide-ranging effects on male fertility, fitness, and genome-wide gene expression. The genetic basis of this phenotypic variation is difficult to study, in part because we do not know the detailed organization of the Y chromosome. To study Y chromosome organization in D. melanogaster, we develop an assembly strategy involving the in silico enrichment of heterochromatic long single-molecule reads and use these reads to create targeted de novo assemblies of heterochromatic sequences. We assigned contigs to the Y chromosome using Illumina reads to identify male-specific sequences. Our pipeline extends the D. melanogaster reference genome by 11.9 Mb, closes 43.8% of the gaps, and improves overall contiguity. The addition of 10.6 MB of Y-linked sequence permitted us to study the organization of repeats and genes along the Y chromosome. We detected a high rate of duplication to the pericentric regions of the Y chromosome from other regions in the genome. Most of these duplicated genes exist in multiple copies. We detail the evolutionary history of one sex-linked gene family, crystal-Stellate. While the Y chromosome does not undergo crossing over, we observed high gene conversion rates within and between members of the crystal-Stellate gene family, Su(Ste), and PCKR, compared to genome-wide estimates. Our results suggest that gene conversion and gene duplication play an important role in the evolution of Y-linked genes.
Tearing of Indian mantle lithosphere from high-resolution seismic images and its implications for lithosphere coupling in southern Tibet

What happened to the Indian mantle lithosphere (IML) during the Indian–Eurasian collision and what role it has played on the plateau growth are fundamental questions that remain unanswered. Here, we show clear images of the IML from high-resolution P and S tomography, which suggest that the subducted IML is torn into at least four pieces with different angles and northern limits, shallower and extending further in the west and east sides while steeper in the middle. Intermediate-depth earthquakes in the lower crust and mantle are located almost exclusively in the high-velocity (and presumably strong) part of the Indian lithosphere. The tearing of the IML provides a unified mechanism for Late Miocene and Quaternary rifting, current crustal deformation, and intermediate-depth earthquakes in the southern and central Tibetan Plateau and suggests that the deformations of the crust and the mantle lithosphere are strongly coupled.
Foreign competition and acquisitions

Abstract I provide evidence on the impact of foreign competition on firms' propensities to engage in mergers and acquisitions. Using import tariff reductions as exogenous shocks that increase foreign competition, I find that affected firms are more likely to make acquisitions following tariff reductions. Cross-sectional tests show that this association is more pronounced for single segment firms, capital intensive firms, firms with higher profit margins, and firms with better growth opportunities, which suggests that this association is stronger for firms that are affected by increased competition to a greater extent and firms that stand to gain more from acquisitions when faced with increased competition. Moreover, the positive relation between acquisition propensities and tariff cuts is more pronounced for financially unconstrained firms and during times of high capital liquidity, which implies that it is easier for firms with greater access to capital to respond to increases in foreign competition by making acquisitions. Finally, I find some evidence that the acquisitions made in response to tariff decreases are associated with better firm profitability ratios in the following year, indicating that firms respond to increased competition by making acquisitions to improve their operational efficiency.
Graph-Counting Polynomials for Oriented Graphs

If $$\mathcal{F}$$ is a set of subgraphs F of a finite graph E we define a graph-counting polynomial $$p_\mathcal{F}(z)=\sum _{F\in \mathcal{F}}z^{|F|}$$ In the present note we consider oriented graphs and discuss some cases where $$\mathcal{F}$$ consists of unbranched subgraphs E. We find several situations where something can be said about the location of the zeros of $$p_\mathcal{F}$$ .
Probabilistic Blocking with an Application to the Syrian Conflict

Entity resolution seeks to merge databases as to remove duplicate entries where unique identifiers are typically unknown. We review modern blocking approaches for entity resolution, focusing on those based upon locality sensitive hashing (LSH). First, we introduce k-means locality sensitive hashing (KLSH), which is based upon the information retrieval literature and clusters similar records into blocks using a vector-space representation and projections. Second, we introduce a subquadratic variant of LSH to the literature, known as Densified One Permutation Hashing (DOPH). Third, we propose a weighted variant of DOPH. We illustrate each method on an application to a subset of the ongoing Syrian conflict, giving a discussion of each method.
Overall constitutive description of symmetric layered media based on scattering of oblique SH waves

Abstract This papers investigates the scattering of oblique shear horizontal (SH) waves off finite periodic media made of elastic and viscoelastic layers. It further considers whether a Willis-type constitutive matrix (in temporal and spatial Fourier domain) may reproduce the scattering matrix (SM) of such a system. In answering this question the procedure to determine the relevant overall constitutive parameters for such a medium is presented. To do this, first the general form of the dispersion relation and impedances for oblique SH propagation in such coupled Willis-type media are developed. The band structure and scattering of layered media are calculated using the transfer matrix (TM) method. The dispersion relation may be derived based on the eigen-solutions of an infinite periodic domain. The wave impedances associated with the exterior surfaces of a finite thickness slab are extracted from the scattering of such a system. Based on reciprocity and available symmetries of the structure and each constituent layer, the general form of the dispersion and impedances may be simplified. The overall quantities may be extracted by equating the scattering data from TM with those expected from a Willis-type medium. It becomes evident that a Willis-type coupled constitutive tensor with components that are assumed independent of wave vector is unable to reproduce all oblique scattering data. Therefore, non-unique wave vector dependent formulations are introduced, whose SM matches that of the layered media exactly. It is further shown that the dependence of the overall constitutive tensors of such systems on the wave vector is not removable even at very small frequencies and incidence angles and that analytical considerations significantly limit the potential forms of the spatially dispersive constitutive tensors.
How Consumer Price Subsidies affect Nutrition

Summary We study the effect of an exogenous increase in food grain subsidy from a program targeting the poor in rural India and find that the increase in income resulting from the subsidy increased consumption of the subsidized grains and certain more expensive sources of nutrition, lowered consumption of coarse grains, the cheaper, yet, unsubsidized staple food, and increased expenditures on nonfood items but had no effect on nutrition in poor households. Estimates of the price effect of the subsidy on nutrition are also negligible; the price subsidy increased consumption of wheat and rice and lowered consumption of coarse grains.
The Intractability of Inaccurate Eyewitness Identification

Inaccurate eyewitness testimony is a leading cause of wrongful convictions. As early as 1967, the U.S. Supreme Court recognized this danger, but the tests it promulgated to distinguish reliable fro...
Multi-Stream LDPC Decoder on GPU of Mobile Devices

Low-density parity check (LDPC) codes have been extensively applied in mobile communication systems due to their excellent error correcting capabilities. However, their broad adoption has been hindered by the high complexity of the LDPC decoder. Although to date, dedicated hardware has been used to implement low latency LDPC decoders, recent advancements in the architecture of mobile processors have made it possible to develop software solutions. In this paper, we propose a multi-stream LDPC decoder designed for a mobile device. The proposed decoder uses graphics processing unit (GPU) of a mobile device to achieve efficient real-time decoding. The proposed solution is implemented on an NVIDIA Tegra board as a system on a chip (SoC), where our results indicate that we can control the load on the central processing units through the multi-stream structure.
R & Q Analysis†

This entry discusses five alternative criteria for performing principal components analysis on a data matrix. These criteria differ in whether the data are corrected for the variable means, the observation means, both variable and observation means, or neither of them. Keywords: principal component analysis; covariance matrix; correlation matrix; singular value decomposition
Mission Analysis and Emissions for Conventional and Hybrid-Electric Commercial Transport Aircraft

A feasibility study of a hybrid-electric commercial transport aircraft was conducted by analyzing the simulated performance and lifecycle carbon dioxide (CO2) emissions of a conventional single-ais...
Convergence and the colonization of custom in pre-modern Europe

This paper argues that once men trained in the learned laws during the Middle Ages, they could no longer conceive of custom in the traditional manner, but rewrote the narrative of custom to fit into the framework of law established by the Roman law.
Ecopracticology : the study of socio-ecological practice

In this communication, the author defines ecopracticology as a legitimate field of scholarly inquiry, discusses its theoretical independence and interdependence, introduces Socio-Ecological Practice Research (SEPR) as its home journal, and pays tribute to those who contributed to the field’s development. In compliance with journal’s requirements for the article type Communication, presentations are concise; footnotes are used as needed to compensate brevity.
UNA "PRINCESA TRISTE, QUE HA PERDIDO LA RISA, QUE HA PERDIDO EL COLOR". CUERPO Y VIOLENCIA EN CIERRA LOS OJOS, PRINCESA DE JOSÉ ALEJANDRO CASTAÑO

espanolEl presente articulo pretende analizar la construccion de un cuerpo de la violencia en la novela Cierra los ojos, princesa (2012) de Jose Alejandro Castano (Medellin, 1972). Para esto, se recurrira a una lectura de las multiples tipologias de cuerpos que se elaboran en esta narrativa, para lo cual se contara con autores teoricos como David Le Breton, Jean Luc Nancy y Yuber Rojas Ariza. El aporte de este texto radicaria en entender un periodo de la historia colombiana mediante la incorporacion a la literatura de una corporalidad necro-logica de la violencia contemporanea. EnglishThe aim of this article is to analise the construction of a body of violence in the novel Cierra los ojos, princesa written by Jose Alejandro Castano (Medellin, 1972). To do this, there will be a reading of the multiple types of bodies that are elaborated in this narrative following the guidance of theoretical authors such as David Le Breton, Jean Luc Nancy y Yuber Rojas Ariza. This text would contribute to understand a period of Colombian history by way of the incorporation of a necro-logic corporality of contemporary violence into literature.
Comparing time series transcriptome data between plants using a network module finding algorithm

Comparative transcriptome analysis is the comparison of expression patterns between homologous genes in different species. Since most molecular mechanistic studies in plants have been performed in model species, including Arabidopsis and rice, comparative transcriptome analysis is particularly important for functional annotation of genes in diverse plant species. Many biological processes, such as embryo development, are highly conserved between different plant species. The challenge is to establish one-to-one mapping of the developmental stages between two species. In this manuscript, we solve this problem by converting the gene expression patterns into co-expression networks and then apply network module finding algorithms to the cross-species co-expression network. We describe how such analyses are carried out using bash scripts for preliminary data processing followed by using the R programming language for module finding with a simulated annealing method. We also provide instructions on how to visualize the resulting co-expression networks across species. We provide a comprehensive pipeline from installing software and downloading raw transcriptome data to predicting homologous genes and finding orthologous co-expression networks. From the example provided, we demonstrate the application of our method to reveal functional conservation and divergence of genes in two plant species.
A few comments on a result of A. Novikov and Girsanov's theorem

We give a simple proof that for a continuous local martingale Mt lim_e↓0⁡elog⁡Ee(1−e)⟨M⟩∞/2<∞⟹Eexp⁡(M∞−⟨M⟩∞/2)=1.