cssi/SciSciGPT-SciSciNet huggingface dataset:
The Female Athlete Triad: A Metabolic Phenomenon

The Female Athlete Triad (Triad) is a syndrome in which low energy availability triggers a broad range of endocrine mechanisms that conserve energy expenditure, and thereby impairs reproductive and skeletal health. Energy availability is the amount of dietary energy remaining after exercise training for all other physiological functions each day. The specific kind of reproductive dysfunctions caused by low energy availability are functional hypothalamic menstrual disorders. To ensure that affected athletes receive appropriate care, endocrine tests are required to diagnose these disorders by the exclusion of other types of menstrual disorders unrelated to the Triad. In addition, low energy availability impairs skeletal health by uncoupling bone turnover, in which the rate of bone resorption increases while the rate of bone formation declines. The result is a progressive loss or failure to accrue bone mass, which increases the risks of stress fractures and osteoporosis. Low energy availability originates in one or more of three sources: restrictive eating disorders, especially anorexia nervosa; intentional efforts to lose body weight or body fat to improve athletic performance or appearance; and the inadvertent suppression of appetite by exercise and diets containing a high percentage of carbohydrates. It is necessary to know the origin of low energy availability in a particular athlete in order to intervene effectively with her. The key behavior modification for preventing and treating the Triad is to increase energy availability, either by increasing dietary energy intake, reducing exercise energy expenditure, or both. Guidelines for doing so are provided.
Consistent nonparametric estimation for heavy-tailed sparse graphs

We study graphons as a nonparametric generalization of stochastic block models, and show how to obtain compactly represented estimators for sparse networks in this framework. In contrast to previous work, we relax the usual boundedness assumption for the generating graphon and instead assume only integrability, so that we can handle networks that have long tails in their degree distributions. We also relax the usual assumption that the graphon is defined on the unit interval, to allow latent position graphs based on more general spaces. We analyze three algorithms. The first is a least squares algorithm, which gives a consistent estimator for all square-integrable graphons, with errors expressed in terms of the best possible stochastic block model approximation. Next, we analyze an algorithm based on the cut norm, which works for all integrable graphons. Finally, we show that clustering based on degrees works whenever the underlying degree distribution is atomless.
Distribution-Free, Risk-Controlling Prediction Sets

While improving prediction accuracy has been the focus of machine learning in recent years, this alone does not suffice for reliable decision-making. Deploying learning systems in consequential settings also requires calibrating and communicating the uncertainty of predictions. To convey instance-wise uncertainty for prediction tasks, we show how to generate set-valued predictions from a black-box predictor that control the expected loss on future test points at a user-specified level. Our approach provides explicit finite-sample guarantees for any dataset by using a holdout set to calibrate the size of the prediction sets. This framework enables simple, distribution-free, rigorous error control for many tasks, and we demonstrate it in five large-scale machine learning problems: (1) classification problems where some mistakes are more costly than others; (2) multi-label classification, where each observation has multiple associated labels; (3) classification problems where the labels have a hierarchical structure; (4) image segmentation, where we wish to predict a set of pixels containing an object of interest; and (5) protein structure prediction. Lastly, we discuss extensions to uncertainty quantification for ranking, metric learning and distributionally robust learning.
Graph-based Topological Exploration Planning in Large-scale 3D Environments

Currently, state-of-the-art exploration methods maintain high-resolution map representations in order to optimize exploration goals in each step that maximizes information gain. However, during exploring, those "optimal" selections could quickly become obsolete due to the influx of new information, especially in large-scale environments, and result in high-frequency re-planning that hinders the overall exploration efficiency. In this paper, we propose a graph-based topological planning framework, building a sparse topological map in three-dimensional (3D) space to guide exploration steps with high-level intents so as to render consistent exploration maneuvers. Specifically, this work presents a novel method to estimate 3D space’s geometry with convex polyhedrons. Then, the geometry information is utilized to group space into distinctive regions. And those regions are added as nodes into the topological map, directing the exploration process. We compared our method with the state-of-the-art in simulated environments. The proposed method achieves higher space coverage and outperforms exploration efficiency by more than 40% during experiments. Finally, a field experiment was conducted to further evaluate the applicability of our method to empower efficient and robust exploration in real-world environments.
Prey‐driven behavioral habitat use in a low‐energy ambush predator

Food acquisition is an important modulator of animal behavior and habitat selection that can affect fitness. Optimal foraging theory predicts that predators should select habitat patches to maximize their foraging success and net energy gain, likely achieved by targeting areas with high prey availability. However, it is debated whether prey availability drives fine-scale habitat selection for predators. We assessed whether an ambush predator, the timber rattlesnake (Crotalus horridus), exhibits optimal foraging site selection based on the spatial distribution and availability of prey. We used passive infrared camera trap detections of potential small mammal prey (Peromyscus spp., Tamias striatus, and Sciurus spp.) to generate variables of prey availability across the study area and used whether a snake was observed in a foraging location or not to model optimal foraging in timber rattlesnakes. Our models of small mammal spatial distributions broadly predicted that prey availability was greatest in mature deciduous forests, but T. striatus and Sciurus spp. exhibited greater spatial heterogeneity compared with Peromyscus spp. We found the spatial distribution of cumulative small mammal encounters (i.e., overall prey availability), rather than the distribution of any one species, to be highly predictive of snake foraging. Timber rattlesnakes appear to forage where the probability of encountering prey is greatest. Our study provides evidence for fine-scale optimal foraging in a low-energy, ambush predator and offers new insights into drivers of snake foraging and habitat selection.
Compensatory functional connectome changes in a rat model of traumatic brain injury

Penetrating cortical impact injuries alter neuronal communication beyond the injury epicentre, across regions involved in affective, sensorimotor and cognitive processing. Understanding how traumatic brain injury reorganizes local and brain wide nodal interactions may provide valuable quantitative parameters for monitoring pathological progression and recovery. To this end, we investigated spontaneous fluctuations in the functional MRI signal obtained at 11.1 T in rats sustaining controlled cortical impact and imaged at 2- and 30-days post-injury. Graph theory-based calculations were applied to weighted undirected matrices constructed from 12 879 pairwise correlations between functional MRI signals from 162 regions. Our data indicate that on Days 2 and 30 post-controlled cortical impact there is a significant increase in connectivity strength in nodes located in contralesional cortical, thalamic and basal forebrain areas. Rats imaged on Day 2 post-injury had significantly greater network modularity than controls, with influential nodes (with high eigenvector centrality) contained within the contralesional module and participating less in cross-modular interactions. By Day 30, modularity and cross-modular interactions recover, although a cluster of nodes with low strength and low eigenvector centrality remain in the ipsilateral cortex. Our results suggest that changes in node strength, modularity, eigenvector centrality and participation coefficient track early and late traumatic brain injury effects on brain functional connectivity. We propose that the observed compensatory functional connectivity reorganization in response to controlled cortical impact may be unfavourable to brain wide communication in the early post-injury period.
Emerging nonlinear Hall effect in Kane-Mele two-dimensional topological insulators

The recent observations of nonlinear Hall effect in time-reversal symmetry protected systems and on the surface of three-dimensional topological insulators due to an in-plane magnetic field have attracted immense experimental and theoretical investigations in two-dimensional transition metal dichalcogenides and Weyl semimetals. The origin of this type of second order effect has been attributed to the emergence of a Berry curvature dipole, which requires a low-symmetry environment. Here, we propose a mechanism for generating such a second order nonlinear Hall effect in Kane-Mele two-dimensional topological insulators due to spatial and time reversal symmetry breaking in the presence of Zeeman and Rashba couplings. By actively tuning the energy gaps with external electromagnetic fields we also demonstrate that the nonlinear Hall effect shows remarkable signatures of topological phase transitions existing in the considered two-dimensional systems.
Residual state ownership, foreign ownership and firms' financing patterns

Abstract Would different types of ownerships affect each other's effect on firm behavior? We investigate the effect of residual state ownership, foreign ownership, and the interaction between the two on firms' financing patterns, employing the World Bank Enterprise Survey (WBES) dataset, which covers over 130 thousand firms in 139 economies from 2006 to 2017. We find that neither firms with residual state ownership only nor firms with foreign ownership only are positively related with external finance. In comparison, firms with both state and foreign ownerships are associated with higher external finance. The coefficient of the state-foreign interaction is both statistically and economically significant. The increased external finance for firms with both state and foreign ownerships mainly comes from private banks and new equity. Moreover, we explore the channels through which residual state ownership and/or foreign ownership affect firms' financing patterns. Firms with residual state ownership only or foreign ownership only do not actively expand in the market or innovate their products. While firms with both state and foreign ownerships are eagerly engaging in market expansion and product innovation.
Imitating Deep Learning Dynamics via Locally Elastic Stochastic Differential Equations

Understanding the training dynamics of deep learning models is perhaps a necessary step toward demystifying the effectiveness of these models. In particular, how do data from different classes gradually become separable in their feature spaces when training neural networks using stochastic gradient descent? In this study, we model the evolution of features during deep learning training using a set of stochastic differential equations (SDEs) that each corresponds to a training sample. As a crucial ingredient in our modeling strategy, each SDE contains a drift term that reflects the impact of backpropagation at an input on the features of all samples. Our main finding uncovers a sharp phase transition phenomenon regarding the {intra-class impact: if the SDEs are locally elastic in the sense that the impact is more significant on samples from the same class as the input, the features of the training data become linearly separable, meaning vanishing training loss; otherwise, the features are not separable, regardless of how long the training time is. Moreover, in the presence of local elasticity, an analysis of our SDEs shows that the emergence of a simple geometric structure called the neural collapse of the features. Taken together, our results shed light on the decisive role of local elasticity in the training dynamics of neural networks. We corroborate our theoretical analysis with experiments on a synthesized dataset of geometric shapes and CIFAR-10.
Genome-wide Imputation Using the Practical Haplotype Graph in the Heterozygous Crop Cassava.

Genomic applications such as genomic selection and genome-wide association have become increasingly common since the advent of genome sequencing. The cost of sequencing has decreased in the past two decades, however genotyping costs are still prohibitive to gathering large datasets for these genomic applications, especially in non-model species where resources are less abundant. Genotype imputation makes it possible to infer whole genome information from limited input data, making large sampling for genomic applications more feasible. Imputation becomes increasingly difficult in heterozygous species where haplotypes must be phased. The Practical Haplotype Graph is a recently developed tool that can accurately impute genotypes, using a reference panel of haplotypes. We showcase the ability of the Practical Haplotype Graph to impute genomic information in the highly heterozygous crop cassava (Manihot esculenta). Accurately phased haplotypes were sampled from runs of homozygosity across a diverse panel of individuals to populate PHG, which proved more accurate than relying on computational phasing methods. The Practical Haplotype Graph achieved high imputation accuracy, using sparse skim-sequencing input, which translated to substantial genomic prediction accuracy in cross validation testing. The Practical Haplotype Graph showed improved imputation accuracy, compared to a standard imputation tool Beagle, especially in predicting rare alleles.
Test-time Collective Prediction

An increasingly common setting in machine learning involves multiple parties, each with their own data, who want to jointly make predictions on future test points. Agents wish to benefit from the collective expertise of the full set of agents to make better predictions than they would individually, but may not be willing to release their data or model parameters. In this work, we explore a decentralized mechanism to make collective predictions at test time, leveraging each agent's pre-trained model without relying on external validation, model retraining, or data pooling. Our approach takes inspiration from the literature in social science on human consensus-making. We analyze our mechanism theoretically, showing that it converges to inverse meansquared-error (MSE) weighting in the large-sample limit. To compute error bars on the collective predictions we propose a decentralized Jackknife procedure that evaluates the sensitivity of our mechanism to a single agent's prediction. Empirically, we demonstrate that our scheme effectively combines models with differing quality across the input space. The proposed consensus prediction achieves significant gains over classical model averaging, and even outperforms weighted averaging schemes that have access to additional validation data.
Early-stopped neural networks are consistent

This work studies the behavior of neural networks trained with the logistic loss via gradient descent on binary classification data where the underlying data distribution is general, and the (optimal) Bayes risk is not necessarily zero. In this setting, it is shown that gradient descent with early stopping achieves population risk arbitrarily close to optimal in terms of not just logistic and misclassification losses, but also in terms of calibration, meaning the sigmoid mapping of its outputs approximates the true underlying conditional distribution arbitrarily finely. Moreover, the necessary iteration, sample, and architectural complexities of this analysis all scale naturally with a certain complexity measure of the true conditional model. Lastly, while it is not shown that early stopping is necessary, it is shown that any univariate classifier satisfying a local interpolation property is necessarily inconsistent.
Pharmacologic profiling reveals lapatinib as a novel antiviral against SARS-CoV-2 in vitro

Abstract The emergence of SARS-CoV-2 virus has resulted in a worldwide pandemic, but effective antiviral therapies are not widely available. To improve treatment options, we conducted a high-throughput screen to uncover compounds that block SARS-CoV-2 infection. A minimally pathogenic human betacoronavirus (OC43) was used to infect physiologically-relevant human pulmonary fibroblasts (MRC5) to facilitate rapid antiviral discovery in a preclinical model. Comprehensive profiling was conducted on more than 600 compounds, with each compound arrayed across 10 dose points. Our screening revealed several FDA-approved agents that can attenuate both OC43 and SARS-CoV-2 viral replication, including lapatinib, doramapimod, and 17-AAG. Importantly, lapatinib inhibited SARS-CoV-2 RNA replication by over 50,000-fold. Further, both lapatinib and doramapimod could be combined with remdesivir to improve antiviral activity in cells. These findings reveal novel therapeutic avenues that could limit SARS-CoV-2 infection.
Responsibility and Organization Science: Integrating Micro and Macro Perspectives

Responsibility is an important issue in organizations and society. Employees, managers, and owners can behave responsibly in the workplace and beyond. In addition, these individuals can be influenc...
Outgoing Small Claims President's Message

This column discusses the priorities and accomplishments of the New York City Civil Court's Association of Small Claims Arbitrators.
Preclinical alphavirus immunotherapy for NPM/ALK+ lymphoma in a mouse model

Proc Amer Assoc Cancer Res, Volume 46, 2005 6043 Background: Twenty to 30% of large cell lymphomas in children are classified as non-Hodgkin’s anaplastic large cell lymphomas (ALCL). Of these, the NPM/ALK oncogene occurs in 50% and stimulates both ALK specific antibodies and cytotoxic T cells, associated with better outcome. Objective: We propose to deliver NPM/ALK to antigen presenting cells (APC) for a robust immune response to treat lymphoma in a ALCL mouse model. Methods: APC of the popliteal lymph node were infected by one round of replicating Venezuelan equine encephalitis virus replicon particles expressing NPM/ALKmut (NPM/LK-VRP) by injecting VRP subcutaneously into the footpad of BALB/cJ female mice. VRP were delivered either prior to or after an intravenous (i.v.) injection of stably transformed BaF3-NPM/ALK pro-B cells to protect against or regress tumor establishment, respectively. To protect against ALCL, NPM/LK-VRP or the VRP control, GFP-VRP, at 1e6 infectious units was given in a prime-boost fashion 3 weeks apart, followed 3 weeks later by tumor challenge. To regress ALCL, VRP were given 2, 5 or 7 days after tumor cells with a prime and 2 boosts 3 weeks apart. Results: Mice inoculated i.v. with tumor cells developed two phases of death; one by 2 months with 50-70% mortality and one by 4-6 months with 10% mortality. Tumors were found most frequently in lymphoid tissues, whereas metastasis was found most frequently in the ovary, followed by liver, kidneys and lung. There was a male predominance in mortality from ALCL in two sub-stains of BALB/c mice. BALB/cANn Tac (Logrank, P=0.0205) and BALB/cJ (Logrank, P=0.0493) survival curves were similar with more males dying (0-7% survival) moderately faster (32-56 d median survival) than females (25-52% survival/ 36-149 d median survival). Pre-treatment of BALB/cJ mice with NPM/ALK-VRP compared to the VRP control significantly increased survival following tumor transfer (80% and 10%, respectively; P=0.0077). Regression of ALCL 2 days after tumor cell delivery occurred with NPM/ALK-VRP as survival was increased compared to the PBS vehicle (100% and 30%, respectively, P<0.0001). Administration of the vaccine 7 days after tumor cells resulted in a decrease in the vaccine specific response. A rechallenge of tumor cells in the 2- and 7-day regression resulted in a only a ≤10% further increase in mortality, indicating long-lived protection. Conclusion: Administration of NPM/ALK-VRP vaccine in mice protected against tumor establishment and regressed ALCL. The addition of immunotherapy to conventional therapy may improve the outcome of 30% of patients with ALCL who do not recover from their disease despite aggressive intervention.
The Blind Side

The Blind Side is based on the true story of famed football player, Michael Oher. The film begins when Michael is enrolled in a private, Christian school on the opposite side of town from the proje...
Different pharmacokinetics of tramadol in mothers treated for labour pain and in their neonates. Towards an increased knowledge of paediatric clinical pharmacology.

. Tramadol and O-desmethyl-tramadol, its M1 metabolite, freely reach the neonate indicating a high placental permeability. . At the time of birth there is no indication that either tramadol or its M1 metabolite is lost during foetal passage. . The neonate already possesses the complete hepatic capacity for the metabolism of tramadol into its active metabolite. . The ‘renal’ elimination of the tramadol metabolite M1 is considerably attenuated in the neonate during the first 12 h postpartum compared to adults.
Cell-Free Amino Acid-Incorporating System from Pseudomonas indigofera

Shiio, Tsuru (Washington State University, Pullman), and Bruce A. McFadden. Cell-free amino acid-incorporating system from Pseudomonas indigofera. J. Bacteriol. 90:978–983. 1965.—A cell-free preparation from Pseudomonas indigofera incorporated C14-phenylalanine and C14-leucine into a product which was insoluble in hot trichloroacetic acid. The phenylalanine incorporation process, which had a temperature optimum of 30 C and a pH optimum of 7.6, had many characteristics of protein synthesis. The process depended upon both “ribosomes” and supernatant fraction from centrifugation at 105,000 × g. Incorporation required adenosine triphosphate, apparently depended upon guanosine triphosphate, and was inhibited by chloramphenicol, puromycin, actinomycin, ribonuclease, and deoxyribonuclease. Leucine incorporation was also studied and had many similar characteristics. C14-phenylalanine uptake was stimulated by sRNA or polyuridylic acid, and together these substances had a synergistic effect upon stimulation. The incorporation of C14-phenylalanine into a product which was precipitated by antiserum to crystalline isocitrate lyase was also observed.
Relation of Frequency of Collection to Amount of Semen Obtained from Turkey Males

Abstract IN A study of seasonal variation of semen production by turkey males Carson et al. (1955, a, b) obtained monthly flock-average semen volumes varying from barely measurable amounts to over 0.3 ml. During the period late February to late May the average volume was 0.24 and 0.27 ml. in two successive years. These figures are low as compared with those previously reported, e.g., by Burrows and Marsden (1938) who obtained 0.1 to 0.7 ml. with averages of 0.3 and 0.4, and by Parker (1946) who reported an average production of 0.33 ml. On the other hand, average estimates of sperm concentration obtained by Carson et al. (1955b) were higher (10.26 and 16.7 billions per ml.) than the 8.4 billions reported by Parker (1946), yielding estimates of numbers of sperm per ejaculate in the same order of magnitude: 2.3 and 4.5 billion from the data of Carson et al. and 2.8 …
Unearthing the nonassociative origins of fears and phobias: A rejoinder

In recent years numerous disagreements and controversies have ensued over the place of Pavlovian or associative conditioning in the etiology of specific phobias and other fear-related clinical syndromes. A major source of disagreement emerged from clinical observations suggesting that environmental aversive conditioning events could not be identified for many specific phobias. Part of the controversy can also be traced to disagreements over what constitutes a direct conditioning event and over what exactly is being conditioned in phobic acquisition. More fundamental, however, is confusion over the critical process variables involved in the conditioning etiology of human phobias and fear-related clinical syndromes. We address some of the recent controversies surrounding associative conditioning accounts of phobic onset in light of recent proposals that nonassociative factors account for the etiology of many specific phobias. The viability of the nonassociative position is questioned and alternatives are suggested that emphasize the complex and multifaceted processes involved in the etiology of specific phobias.
A new route to the Ni(O) ‘cradle’ complex Ni2(μ-CO)(CO)2(PPh2CH2PPh2)2: μ-CO ligand and metal-centered reactivity

We report a new synthesis of the complex Ni 2 (μ-CO)(CO) 2 (dppm) 2 (dppm=bis(diphenylphosphino(methane)) and present evidence for both metal-centered and μ-carbonyl oxygen atom reactivity
Critical Elements of Development Impact‐Fee Programs

Development impact fees have become a major source of new capital revenue for local governments. The need for new revenue is occasioned by declining federal public works funds, rising construction standards and costs, and increasing unwillingness of voters to pass tax increases. Communities thus look to new development to pay for its own way in part through impact fees. Impact fees are assessed to raise new revenue for the construction of a wide range of facilities. They are also being assessed by an increasingly large number of communities, some of which have no apparent growth problems. Soon, most communities of modest sophistication will assess impact fees. But courts require that impact fees be assessed in particular ways. This paper discusses the critical elements of defensible impact‐fee programs. It includes a review of policy issues, basic legal considerations, general procedures for identifying impacts and assessing impact fees, and principles of administration.
Introduction: United States and Canadian Academy of Pathology Specialty Conference Case Reports

Four pediatric pathologists presented interesting and challenging tumor cases at the Spring 2003 meeting of the United States and Canadian Academy of Pathology. This issue contains the case clinical history, photographic illustrations of pathology, differential diagnosis, final diagnosis, and references for each case presented. Ashley Hill beautifully summarized pleuropulmonary blastoma and informed all of the national registry for this tumor. John Hicks reminded us of the necessity to correlate pathology with clinical and radiographic findings, especially in the diagnosis of bone tumors. Cheryl Coffin reviewed the pathologic and clinical challenges of vascular tumors, including changes seen after therapy. David Parham closed the evening session with a discussion of bone tumors, the World Health Organization classification, and cytogenetics findings. Whether you had the pleasure of hearing these discussions in person or were unable to attend, the papers will serve as an excellent review and reference for your next pediatric tumor.
Charge-symmetry breaking forces and isospin mixing in 8 Be

We report Green's function Monte Carlo calculations of isospin-mixing (IM) matrix elements for the ${2}^{+}$, ${1}^{+}$, and ${3}^{+}$ $T=0$ and 1 pairs of states at 16--19 MeV excitation in ${}^{8}$Be. The realistic Argonne ${v}_{18}$ (AV18) two-nucleon and Illinois-7 three-nucleon potentials are used to generate the nuclear wave functions. Contributions from the full electromagnetic interaction and strong class III charge-symmetry breaking (CSB) components of the AV18 potential are evaluated. We also examine two theoretically more complete CSB potentials based on $\ensuremath{\rho}$-$\ensuremath{\omega}$ mixing, tuned to give the same neutron-neutron scattering length as AV18. The contribution of these different CSB potentials to the ${}^{3}$H-${}^{3}$He, ${}^{7}$Li-${}^{7}$Be, and ${}^{8}$Li-${}^{8}$B isovector energy differences is evaluated and reasonable agreement with experiment is obtained. Finally, for the ${}^{8}$Be IM calculation we add the small class IV CSB terms coming from one-photon, one-pion, and one-$\ensuremath{\rho}$ exchange, as well as $\ensuremath{\rho}$-$\ensuremath{\omega}$ mixing. The expectation values of the three CSB models vary by up to 20% in the isovector energy differences, but only by 10% or less in the IM matrix element. The total matrix element gives 85--90% of the experimental IM value of $\ensuremath{-}145$ keV for the ${2}^{+}$ doublet, with about two thirds coming from the Coulomb interaction. We also report the IM matrix element to the first ${2}^{+}$ state at 3 MeV excitation, which is the final state for various tests of the standard model for $\ensuremath{\beta}$ decay.
Growth of High-Density Parallel Arrays of Long Single-Walled Carbon Nanotubes on Quartz Substrates

Herein we report a CVD approach to prepare high-density and perfectly aligned arrays of long SWNTs on stable temperature (ST)-cut quartz substrates using copper as catalyst and ethanol as carbon source. Compared with earlier reports, we have demonstrated that the aligned nanotube arrays can be grown on ST quartz substrate without the need of thermal annealing. The density can reach >50 nanotubes per micron and the length can be a few millimeters. Additionally, we have obtained direct proof on the “tip-growth” mechanism for the aligned nanotubes and important evidence that explained the termination of the growth.
Atmospheric Dynamics on the Outer Planets

Flow patterns in the outer planets are complex and not well understood. In his Perspective, Gierasch comments on new results presented by Cho and Polvani in this issue (p. 335) in which a shallow-fluid dynamical model was used to simulate the atmospheric flows on Jupiter, Saturn, Neptune, and Uranus. Several features of the observed flows, including the behavior of the jets and eddies, are captured in the model.
A comparison of laparoscopic and open pyloromyotomy at a teaching hospital

Abstract Background/Purpose: An increasing number of pediatric surgeons are using the laparoscopic approach to treat pyloric stenosis. The advantage of laparoscopic pyloromyotomy is uncertain and has not been evaluated in the setting of a pediatric surgery fellowship program. Methods: The authors retrospectively reviewed the medical records of all patients who underwent pyloromyotomy for congenital hypertrophic pyloric stenosis at their institution from January 1, 1997 through December 31, 2000 (n = 117). Information obtained included age, sex, weight, admission laboratory values, attending surgeon, resident surgeon and their level of training, operating time, intraoperative and postoperative complications, time to full feedings, incidence of postoperative emesis, duration of postoperative emesis, length of stay, and total hospital charges. These variables then were compared between the open (OPEN) and laparoscopic (LAP) groups. Results: From January 1, 1997 through December 31, 2000, 65 LAP and 52 OPEN pyloromyotomies were performed. Characteristics of patients in the OPEN and LAP groups were similar. The mean operating time was 33 ± 2 minutes for OPEN versus 38 ± 2 minutes for LAP ( P =.07). The incidence of postoperative emesis (LAP, 68%, OPEN, 65%), duration of postoperative emesis (LAP, 7.3 ± 1.2 hours; OPEN, 8.1 ± 1.8 hours), and time to full feedings (LAP, 19.5 ± 1.6 hours; OPEN, 19.5 ± 1.3 hours) did not differ significantly between groups ( P >.05). Mean postoperative length of stay in both groups was similar (LAP, 31 ± 5; OPEN, 28 ± 2 hours; P =.64). Mucosal perforation occurred in 5 patients (8%) in the Lap and 2 patients (4%) in the OPEN group ( P =.39). Postoperative complications occurred in 12 LAP (18%) and 6 OPEN patients (12%, P =.31). Five LAP cases were converted to OPEN. In the LAP group there was one unrecognized mucosal perforation and one incomplete pyloromyotomy both of which required reoperation. As the laparoscopic approach was adopted, general surgery resident participation as operating surgeon in these cases decreased from 81% in 1997 to 19% in 2000. Hospital charges were higher in the LAP group, but not significantly (LAP, $6,676 ± 1,005; OPEN, $5,292 ± 306; P = 27). Conclusions: Laparoscopic pyloromyotomy has progressively become the dominant surgical approach to pyloromyotomy at our institution. The LAP and OPEN approaches have similar outcomes. However, the Lap approach may be associated with increased complication rates, a reduction in general surgery resident operative experience, and higher hospital charges. J Pediatr Surg 37:1068-1071. Copyright 2002, Elsevier Science (USA). All rights reserved.
In Vitro Evaluation of Heparin Fractions: Old vs. New Methods

Conventionally, heparin has been evaluated for its anticoagulant effect by various nonspecific, poorly standardized coagulant methods such as the U.S. Pharmacopeial and other global (APTT) tests. However, these assays are relatively insensitive to heparin fractions and fragments, and give varying with the newer modes of heparin administration. It has become necessary, therefore, to develop other methods able to detect a proper therapeutic/prophylactic level and to evaluate a standard potency for these agents. Newer amidolytic assays utilizing synthetic substrates provide for specific anti-factor Xa or anti-factor IIa evaluation. Although these factors are believed to reflect the antithrombotic effect of heparin and its fractions/fragments, conclusive clinical studies are not available at this time. Interactions with non-AT-III-mediated pathways, the contact, kallikrein-kinin, and fibrinolytic system, other coagulant factors, endothelium, and eicosanoid system all can contribute to the overall antithrombotic response of heparin. Some of these actions are not measurable by current in vitro test methods. Amidolytic, immunochemical, and physical assays using various activators to generate endogenous factor Xa, as well as assays for the detection of metabolic or release products of each of these systems, may be more relevant to in vivo conditions. Specific low molecular weight markers such as fibrinopeptide A, which provide the earliest detection of hemostatic activation, can be measured directly, or an in vitro system can be developed to quantitate the relative generation of these markers. These methods can then be modified to assay the in vitro potency of heparin preparations. With proper consideration of reagent specificity and concentration, molecular interactions, reaction time and temperature, ionic type and concentration, reliable accurate methods for a true in vitro representation of in vivo events may be developed. Clinical assays must measure an endogenous response to therapy and not merely an absolute circulating level of drug. However, a standardized pure enzyme system may be ideal to evaluate the potency of these agents. The development of heparin derivatives necessitates a reassessment of currently practiced laboratory technology. Furthermore, well-defined biochemical methods are required for a standardized evaluation of potency and clinical monitoring of these agents.
The Origin of the 4.5 micron Excess from Dwarf Galaxies

Dwarf galaxies tend to have redder [3.6 micron] - [4.5 micron] Spitzer broadband colors than spirals. To investigate this effect, for a large sample of dwarf galaxies we combine Spitzer fluxes with data at other wavelengths and compare to population synthesis models. Lower metallicity systems are found to have redder [3.6] - [4.5] colors on average, but with considerable scatter. The observed range in [3.6] - [4.5] color is too large to be accounted for solely by variations in stellar colors due to age or metallicity differences; interstellar effects must contribute as well. For the reddest systems, the 4.5 micron luminosity may not be a good tracer of stellar mass. We identify three factors that redden this color in dwarfs. First, in some systems, strong Br-alpha emission contributes significantly to the 4.5 micron emission. Second, in some cases high optical depths lead to strong reddening of the starlight in the Spitzer bands. Third, in some galaxies, the nebular continuum dominates the 4.5 micron flux, and in extreme cases, the 3.6 micron flux as well. The harder UV radiation fields in lower metallicity systems produce both more gaseous continuum in the infrared and more Br-alpha per star formation rate. The combination of these three factors can account for the 4.5 micron excess in our sample galaxies, thus it is not necessary to invoke a major contribution from hot dust to the 4.5 micron band. However, given the uncertainties, we are not able to completely rule out hot dust emission at 4.5 micron. More spectroscopic observations in the 3 - 5 micron range are needed to disentangle these effects.
Learning in analog neural network hardware

Abstract Hardware implementations of neuroprocessor architectures are currently enjoying commercial availability for the first time ever. This development has been caused in part by the requirement for real-time solutions to time critical neural network applications. Massively parallel asynchronous neuromorphic representations are inherently capable of very high computational speeds when properly cast in the “right stuff”, i.e. electronic or optoelectronic hardware. However, hardware based learning in such systems is still at a primitive stage. In practise, simulations are typically performed in software, and the resulting synaptic weight capturing the input-output transformation subsequently quantized and down-loaded onto the neural hardware. However, because of the numerous discrepancies between the software and hardware, such systems are inherently poor in performance. In this paper we report on chip-in-the-loop learning systems assembled from custom analog “building blocks” hardware.
In vitro calcification of rat aorta in serum.

ALTHOUGH hydroxyapatite has been identified as a major component of aortic plaques1, the events leading to its deposition in this tissue are little understood. Recently, we have found that substantial quantities of calcium and phosphate are deposited on to rat aortas during the incubation of this tissue in serum. This finding has provided a useful system for the study of aortic calcification in vitro.
Evaluating Vigilance in a Dynamic Environment: Methodological Issues and Proposals

Decades of vigilance research have contributed much to our understanding of the factors affecting sustained attention. However most of what we know about vigilance has been from studies employing tasks that involve relatively static stimuli presented on relatively uncluttered backgrounds. This bears little resemblance to many modern day vigilance tasks. The present study discusses the challenges and issues in applying the vigilance paradigm and methodology to a dynamic task requiring vigilance in an IED detection task.
Numerical Modeling of Sub-Wavelength Anti-Reflective Structures for Solar Module Applications.

This paper reviews the current progress in mathematical modeling of anti-reflective subwavelength structures. Methods covered include effective medium theory (EMT), finite-difference time-domain (FDTD), transfer matrix method (TMM), the Fourier modal method (FMM)/rigorous coupled-wave analysis (RCWA) and the finite element method (FEM). Time-based solutions to Maxwell’s equations, such as FDTD, have the benefits of calculating reflectance for multiple wavelengths of light per simulation, but are computationally intensive. Space-discretized methods such as FDTD and FEM output field strength results over the whole geometry and are capable of modeling arbitrary shapes. Frequency-based solutions such as RCWA/FMM and FEM model one wavelength per simulation and are thus able to handle dispersion for regular geometries. Analytical approaches such as TMM are appropriate for very simple thin films. Initial disadvantages such as neglect of dispersion (FDTD), inaccuracy in TM polarization (RCWA), inability to model aperiodic gratings (RCWA), and inaccuracy with metallic materials (FDTD) have been overcome by most modern software. All rigorous numerical methods have accurately predicted the broadband reflection of ideal, graded-index anti-reflective subwavelength structures; ideal structures are tapered nanostructures with periods smaller than the wavelengths of light of interest and lengths that are at least a large portion of the wavelengths considered.
The crystal structures of the high and low temperature forms of rhombohedral Cr-doped V2O3

Abstract X-ray diffraction studies of single crystals of (Cr0.01V0.99)2O3 have shown that the transition from the low to high temperature rhombohedral forms of this material proceeds without changing the orientation of the unit cell axes. The structures of both the high and low temperature forms have been determined at 23°C using single crystal x-ray diffraction techniques. Both forms are isomorphous with V2O3, but upon heating the M-M distance across the shared octahedral face increases from 2.700(1) A to 2.747(1) A while the M-M distance across the shared edge increases from 2.884(1) A to 2.917(1) A. The M-O distances increase by a maximum of 0.011A. The low temperature form of (Cr0.01V0.99)2O3 is isostructural with V2O3 while the high temperature form is isostructural with (Cr0.038V0.962)2O3.
Role of the pro‐α2(I) COOH‐terminal region in assembly of type I collagen: Truncation of the last 10 amino acid residues of pro‐α2(I) chain prevents assembly of type I collagen heterotrimer

Procollagen (Type I) contains a noncollagenous COOH-terminal propeptide (C-propeptide) hypoth- esized to be important in directing chain association and alignment during assembly. We previously expressed human pro-a2(I) cDNA in rat liver epithelial cells, W8, that produce only pro-a1(I) trimer collagen (Lim et al. (1994) Matrix Biol. 14: 21-30). In the resulting cell lines, a2(I) assembled with a1(I) forming heterotrimers. Using this cell system, we investigated the importance of the COOH-terminal propeptide sequence of the pro-a2(I) chain for normal assembly of type I collagen. Full-length human pro-a2(I) cDNA was cloned into expression vectors with a premature stop signal eliminating the final 10 amino acids. No triple-helical molecules containing a2(I) were detected in transfected W8 cells, although pro-a2(I) mRNA was detected. Additional protein analysis demonstrated that these cells synthesize small amounts of truncated pro-a2(I) chains detected by immunoprecipitation with a pro-a2(I) antibody. In addition, since the human-rat collagen was less thermostable than normal intraspecies collagen, wild-type and C-terminal truncated mouse cDNAs were expressed in mouse D2 cells, which produced only type I trimers. Results from both systems were consistent, suggesting that the last 10 amino acid residues of the pro-a2(I) chain are important for formation of stable type I collagen. J. Cell. Biochem. 71:216-232, 1998. r 1998 Wiley-Liss, Inc.
Prevalence and Predictors of Abnormal Liver Enzymes in Young Women with Anorexia Nervosa

Objective To determine the prevalence and predictors of abnormal liver enzyme levels in ambulatory young women with anorexia nervosa (AN). Study design In this cross-sectional study of 53 females with AN, serum concentrations of liver enzymes and hormones were measured. Anthropometric, dietary, and body composition information was collected. Correlational analyses were performed between liver enzyme concentrations and these variables. Results Elevated alanine aminotransferase (ALT) and gamma-glutamyl transpeptidase (GGT) levels were found in 14 subjects (26%) and 5 subjects (9%), respectively. ALT and GGT were inversely correlated with body mass index (r = −0.27 to −0.30, P P P = .01). Liver enzyme concentrations did not correlate with dietary variables, except for GGT and percentage of calories from protein (r = 0.28, P = .04). Conclusions Serum ALT and GGT concentrations are inversely related to adiposity in young women with AN. Future studies are needed to determine whether these liver enzyme elevations signify unrecognized, clinically relevant liver disease.
Celiac disease A diagnostic challenge with many facets

Abstract Celiac disease (CD) is an enteropathy occurring in genetically susceptible individuals with HLA DQ2 or DQ8 heterodimer caused by ingestion of certain cereals. Until recently it was generally believed that CD is a rare disorder in the United States. More recently, a screening with antiendomysium antibody (EMA) in healthy blood donors in the United States found the prevalence of EMA-positive individuals to be one in 250. The classical form of CD presents with gastrointestinal symptoms between 6 and 18 months of age. Recent studies have shown that almost 50% of patients with newly diagnosed CD do not present with gastrointestinal symptoms The diagnosis of CD can be established when the characteristic changes of the duodenal mucosa are found in a child with signs and/or symptoms consistent with CD, provided that a full and unequivocal clinical remission after withdrawal of gluten is seen, associated with the disappearance of circulating antibodies. Serologic testing for CD has included testing for food protein-directed antibodies (antigliadin, or AGA) and for an autoantibody (EMA). Recently tissue transglutaminase (tTG) was identified as the autoantigen of celiac disease. An enzyme linked immunosorbent assay (ELISA) for immunoglobulin A (IgA) tTG antibodies was found to be 98.1% sensitive and 94.7% specific in patients with biopsy proven CD. While serology should be utilized to screen for CD, particularly in the higher risk populations, intestinal biopsy should be used to confirm the diagnosis. Total lifelong avoidance of gluten ingestion is the cornerstone treatment for the celiac disease.
Aerosol-Assisted Chemical Vapor Deposition of Lubricating MoS2 Films. Ferrous Substrates and Titanium Film Doping

MoS2 thin films have been deposited onto 52100 steel substrates by aerosol-assisted chemical vapor deposition using the metal-organic precursor tetrakis(diethyl-dithiocarbamato)molybdenum(IV) (1). Analysis of the films indicates growth of an initial, highly crystalline FeS layer exhibiting preferred orientation parallel to the substrate, followed by growth of MoS2 nanoparticles. Friction coefficients for MoS2-coated steel specimens reach 0.10 when tested at 100 °C in air. Tetrakis(tert-butylthiolato)titanium(IV) (2), dissolved with complex 1 in THF solutions, yields nanoparticle films of variable TiO2 content as a result of solvent decomposition on MoS2 and subsequent in situ reaction with the titanium precursor.