cssi/SciSciGPT-SciSciNet huggingface dataset:
Modeling the evolution of operating systems: An empirical study

In this paper, we report on an empirical experiment where we observe, record and analyze the evolution of selected operating systems over the past decades, and derive a statistical model that captures relevant evolutionary laws. This model is derived by quantifying relevant attributes of operating systems, including intrinsic technical factors and time-dependent environmental factors. We use this model to understand past evolution and learn to predict future evolution, not only of individual operating systems, but also of operating systems features. We combine the insights gained from this study with insights gained from other similar empirical experiments to attempt to derive evolutionary laws for software technology trends.
Risk Factors for Renal Stone Formation in Patients with Spinal Cord Injury

Summary— To determine factors that may influence kidney stone formation in spinal cord injury patients, the medical records of 893 patients who had been followed up by the Milwaukee Veterans Administration Medical Center from 1970 to 1984 were extensively reviewed. Urography showed that 12 patients had kidney stones. Twenty-four non-kidney stone patients with a similar age range, sex and duration of time since injury were selected as controls. Variables, such as level of spinal lesion, completeness of neurological dysfunction, presence of ureteric reflux etc, were compared and analysed statistically. The results showed that there was no difference between patients with and those without renal stone as far as the level of spinal injury and completeness of spinal cord lesion were concerned. There was no relationship between kidney stone formation and methods of urinary drainage or the presence of ureteric reflux. However, patients with good bladder control had no renal calculi. Serum creatinine, phosphorus, uric acid and calcium levels were similar in both groups of patients. There was a relationship between sepsis, positive urine culture and kidney stone formation. The absence of physical activity was not a risk factor for renal calculi and patients on a high fibre diet had the same incidence of stones as those on a regular diet.
An orthogonal projection and regularization technique for magnetospheric radio tomography

[1] A challenging problem in ill-posed inverse problems is incorporating prior knowledge of the solution into reconstruction techniques. This problem is particularly important in magnetospheric radio tomography where the path integrated measurements of the target region may be sparse. We present in this paper an orthogonal projection and regularization (OPR) technique that incorporates prior knowledge of magnetospheric parameters from existing models or past measurements into a direct reconstruction algorithm. The OPR scheme extracts first an optimal orthonormal basis containing the main features of the unknowns from an ensemble of modeled or measured snapshots through the proper orthogonal decomposition (POD) and then projects the line-of-sight equations onto the subspace spanned by the empirical orthonormal basis. The resulting low-dimensional model is well-conditioned, its coordinates are uncorrelated, and it contains prior knowledge of the solution. The magnetospheric parameters in the transformed coordinate are reconstructed from the low-dimensional model and quantities in the physical coordinate are easily recovered from the POD transformation. On the basis of magnetohydrodynamic (MHD) simulations and hypothetical satellite constellations, we demonstrate that the POD-based method may perform significantly better than the regularized direct method with sparse path-integrated measurements, combined with a few (5–10) model snapshots.
An Objective Measure of the Subjective Pain Response Resulting from Lumbar Muscle Fatigue Due to Lifting

Pain is one of the body's least understood biological responses. Pain measurement often relies on the perception of the individual without any link to known objective responses within the body. The objective of the study was to relate a quantitative measurement of pain obtained by Magnetic Resonance Spectroscopy (MRS), which analyzes chemical shifts in the brain, to perceived pain responses, as measured by ratings of pain. A lifting task was performed to achieve lumbar musculature fatigue, and induce muscle pain. Prior to, immediately following, and 24-hours post, MRS scans were recorded to document chemicals in the brain. All of the participants elicited significant fatigue during the lifting task that resulted in significant pain immediately following and 24-hrs after fatiguing exertions. However, for the majority of brain chemical responses, there was not a significant pattern. The exception was the significant difference in brain response between males and females. Although the results were not comple...
In Situ Water Sensing in a Nafion Membrane by Fluorescence Spectroscopy

The objective of this work is to use fiber-optic fluorescence spectroscopy to detect changes in the Nafion membrane water content in a fuel cell at several operating conditions. The fluorophore Rhodamine 6G was found to be sensitive to the membrane water content. The fluorescence measurement of the membrane water content predicted the dynamic response of the fuel cell during startup, during operating condition changes, and during many small perturbations. A decrease in the membrane water content was observed as the fuel cell current was increased. The decrease in the water content is attributed to mass-transfer limitations at the anode side of the membrane.
Long CTG·CAG Repeats from Myotonic Dystrophy Are Preferred Sites for Intermolecular Recombination

Homologous recombination was shown to enable the expansion of CTG·CAG repeat sequences. Other prior investigations revealed the involvement of replication and DNA repair in these genetic instabilities. Here we used a genetic assay to measure the frequency of homologous intermolecular recombination between two CTG·CAG tracts. When compared with non-repeating sequences of similar lengths, long (CTG·CAG)n repeats apparently recombine with an ∼60-fold higher frequency. Sequence polymorphisms that interrupt the homogeneity of the CTG·CAG repeat tracts reduce the apparent recombination frequency as compared with the pure uninterrupted repeats. The orientation of the repeats relative to the origin of replication strongly influenced the apparent frequency of recombination. This suggests the involvement of DNA replication in the recombination process of triplet repeats. We propose that DNA polymerases stall within the CTG·CAG repeat tracts causing nicks or double-strand breaks that stimulate homologous recombination. The recombination process is RecA-dependent.
Ordered pairing in liquid metallic hydrogen

We study two possible types of pairing involving the protons of a proposed low-temperature liquid phase metallic hydrogen. Electron-proton pairing, which can result in an insulating phase, is investigated by using an approximate solution of an Eliashberg-type equation for the anomalous self-energy. A very low estimate of the transition temperature is obtained by including proton correlations in the effective interaction. For proton-proton pairing, we derive a new proton pair potential based on the Abrikosov wave function. This potential includes the electron-proton interaction to all orders and has a much larger well depth than is obtained with linear screening methods. This suggests the possibility of either a superfluid paired phase analogous to that in He-3, or alternatively a phase with true molecular pairing.
Axillosubclavian Vein Thrombosis or Paget Schroetter Syndrome: Outcomes of Alternative Surgical Approaches

METHODS: We retrospectively reviewed all venous TOS (vTOS) patients undergoing operation from 08/1995 11/2012. Charts were reviewed and patients divided into two groups. Group I patients underwent thrombolysis followed by FRR + open venous reconstruction. Group II patients underwent thrombolysis and FRR, +/subsequent EVT. Patients were distributed evenly between acute ( 2 weeks) presentations.
Bioinformatics Methods for Studying MicroRNA and ARE-Mediated Regulation of Post-Transcriptional Gene Expression

MicroRNAs (miRNAs) are short single-stranded RNA molecules with 21-22 nucleotides known to regulate post-transcriptional expression of protein-coding genes involved in most of the cellular processes. Prediction of miRNA targets is a challenging bioinformatics problem. AU-rich elements (AREs) are regulatory RNA motifs found in the 3â€™ untranslated regions (UTRs) of mRNAs, and they play dominant roles in the regulated decay of short-lived human mRNAs via specific interactions with proteins. In this paper, the authors review several miRNA target prediction tools and data sources, as well as computational methods used for the prediction of AREs. The authors discuss the connection between miRNA and ARE-mediated post-transcriptional gene regulation. Finally, a data mining method for identifying the co-occurrences of miRNA target sites in ARE containing genes is presented.
The export of metabolites from mitochondria and anaplerosis in insulin secretion

Abstract Combinations of insulin secretagogue-derived metabolites were added to microgram amounts of mitochondria obtained from rat and mouse pancreatic islets and the INS-1 cell line, and the export of citric acid cycle intermediates was surveyed to study anaplerosis in insulin secretion. Cellular levels of metabolites were also measured. In mitochondria from all three tissues, malate production was the most responsive to various substrates. The export of citrate and isocitrate in the presence of pyruvate and most other substrates was small and their levels in intact cells did not change with any secretagogue, except in INS-1 cells where citrate increased slightly. Changes in α-ketoglutarate and glutamate export from mitochondria and levels in intact cells indicate that glutamate can be consumed as a fuel secretagogue, but it is not likely produced as a messenger in insulin secretion. The citrate level may not need to increase in order to provide increased malonyl-CoA for signaling insulin secretion. Unlike some cells, insulin cells probably obtain cytosolic NADPH equivalents by exporting them from mitochondria to the cytosol via a pyruvate malate shuttle or an isocitrate shuttle. Only fuels that can enhance anaplerosis via pyruvate or α-ketoglutarate can be insulin secretagogues.
Long-term use of medications and destructive periodontal disease.

Background: Knowledge of typical medication use among patients with chronic periodontitis or destructive periodontal disease is limited. The aim of this study was to associate periodontitis severity with the use of different classes of medications.Methods: Patients (N = 12,631) who had medical, dental, and pharmaceutical coverage with a health maintenance organization and whose severity of destructive periodontal disease was diagnosed by a dentist or specialist were included in the study. The rate of drug use over 7 years was related to the severity of destructive periodontal disease by means of Poisson regression models.Results: Individuals with moderate to advanced periodontitis had significantly lower fill rates for the respiratory agents (antihistamines: −23%, 95% confidence interval [CI]: −10% to −34%; decongestants: −24%, 95% CI: −13% to −34%; and cough/cold medications: −12%, 95% CI: −3% to −21%) and anti-infective agents (antibiotics: −12%, 95% confidence interval: −6% to −18%; urinary anti-infect...
Visual detection of specific, native interactions between soluble and microbead-tethered alpha-helices from membrane proteins.

Using peptides tethered to polymer microbeads, we have developed a technique for measuring the interactions between the transmembrane α-helices of membrane proteins and for screening combinatorial libraries of peptides for members that interact with specific helices from membrane proteins. The method was developed using the well-characterized homodimerization sequence of the membrane-spanning α-helix from the erythrocyte membrane protein glycophorin A (GPA). As a control, we also tested a variant with a dimer-disrupting alteration of a critical glycine residue to leucine. To test for detectable, native interactions between detergent-solubilized and microbead-tethered α-helices, we incubated fluorescent dye-labeled GPA analogues in sodium dodecyl sulfate solution with microbeads that contained covalently attached GPA analogues. When the dye-labeled peptide in solution and the bead-tethered peptide both contained the native glycophorin A sequence, the microbeads readily accumulated the dye through lateral p...
Inhibition of M-current in cultured rat superior cervical ganglia by linopirdine: mechanism of action studies.

Abstract The mechanism involved in the blockade of M-current by linopirdine was studied in cultured rat superior cervical sympathetic ganglia using whole-cell patch clamp recording. The effects of modulators of intracellular signal transduction pathways on muscarine- or linopirdine-induced inhibition of M-current were compared. Intracellular addition of GDP-β-S (500 μM) attenuated M-current block by muscarine (1 μM) but not that of linopirdine (10 μM). Intracellular dialysis of GTP-γ-S (100 μM) enhanced and prolonged muscarineinduced inhibition of M-current but had no effect on the activity of linopirdine. Intracellular BAPTA (20 mM) also inhibited the effects of muscarine without affecting those of linopirdine. Intracellular application of linopirdine had no effect on either basal M-current amplitude or the ability of linopirdine to block M-current when administered extracellularly. These results indicate that M-current inhibition by linopirdine is unlikely to be either G-protein-mediated or calcium-mediated or to involve an intracellular site of action and are, therefore, consistent with a direct block of the M-channel from its extracellular side.
HIV Preclinical-Clinical Therapeutics Research: central nervous system approaches.

The prevalence of HIV-associated brain disorders is reportedly increasing due, in part, to the prolonged life span of individuals who are surviving well on highly active antiretroviral treatments (HAART). While clinicians report CNS-related deficits that are more subtle in presentation than the frank dementia evident in the pre-HAART era, the milder presentation continues to substantively reduce an individual’s quality of life. The development of novel drugs or therapeutic strategies for treating HIV-related CNS disease is important as most investigators agree that the brain is a sanctuary for latent virus, local viral recrudescence, and associated brain inflammatory responses. The prolonged chronic and cumulative effects on the brain of living with HIV-related inflammatory processes, antiretroviral treatments, and their long-term side effects, toxicities, and brain-related aging processes collectively indicate that the burden of CNS and PNS complications will increase profoundly during the upcoming years. Considering the high expense for new drugs entering CNS-related clinical trials and their ultimately low success rate, the NIMH convened a meeting entitled, HIV Preclinical–Clinical Therapeutics Research Meeting, to discuss the current and proposed novel approaches for neuroAIDS drug development and clinical practices. The purposes of the meeting were twofold: to identify the most promising approaches for future neuroAIDS therapeutics development research and to discuss optimal structures and partnerships with industry that may facilitate the successful movement of compounds from the bench to the bedside. Several themes can be derived from the sessions and are highlighted below for preclinical, translational and clinical neuroAIDS therapeutics research.
A1 noradrenergic input to medial preoptic-medial septal area: an electrophysiological study.

The effects of electrical stimulation of the Al noradrenergic cell group on the extracellular activity of medial preoptic-medial septal (MPO-S) neurons were studied in ovariectomized (OVX) female rats under different hormonal conditions [estrogen and progesterone (E-P)-primed or unprimed] via conventional electrophysiological techniques. In addition, MPO-S neurons responding to the Al noradrenergic cell group stimulation were characterized by examining their connections with the arcuate nucleus/median eminence (ARC/ME). With respect to stimulation of the Al noradrenergic cell group, a large proportion of MPO-S neurons exhibited one of the following three types of orthodromic responses: orthodromic excitation (OD + ), orthodromic inhibition (OD-), or complex orthodromic response (OD comp). The predominant type of response was OD +. Although E-P-priming did not change the relative proportion of neurons displaying a specific type of orthodromic response, it did increase the overall percentage of MPO-S neurons orthodromically responding to Al stimulation (39% of MPO-S neurons responded to Al stimulation in the E-P-primed group whereas only 25% of the neurons did so in the unprimed group). Neurons responsive to Al stimulation were more likely to respond orthodromically to ARC/ME stimulation than were those neurons which were unresponsive to Al stimulation. About one fifth of MPO-S neurons identified as projecting to the ARC/ME [putative luteinizing hormone-releasing hormone (LHRH) neurons] orthodromically responded to Al stimulation. The predominant type of response was OD + . The present study indicates that Al noradrenergic input to MPO-S neurons is predominantly excitatory. Furthermore, the findings that (1) the proportion of neurons which responded to Al stimulation was increased by E-P-priming, a treatment used to induce a surge in luteinizing hormone (LH) secretion in an OVX rat, (2) the neurons responding to Al stimulation had a tendency to receive input from the ARC/ME, a brain site intimately involved in the control of LH release, and (3) the activity of putative LHRH neurons was able to be affected by Al stimulation suggest that Al input to MPO-S area may be involved in the control of LH secretion.
Automated title page cataloging: a feasibility study

Abstract The cost of original cataloging remains a substantial expense for libraries and a hindrance to rapid availability of newly published materials. We have prototyped a rule-based system to explore the impediments to automating descriptive cataloging from title pages. Our test results suggest that it is possible to capture a substantial part of the regularity in title page layout in a small set of rules. Our system correctly identified over 80% of the bibliographic fields present on a random sample of title pages. Significant unsolved problems include the difficulty of incorporating a cataloger's general knowledge about the world in such a system, the complexity and irregularity of cataloging rules, and lack of reliable data capture techniques. Nonetheless, the methods explored hold promise for advancing the state of the art in the automation of cataloging and document format recognition.
Cognitive task performance and symptoms contribute to personality abnormalities in first hospitalized schizophrenia

Chronic schizophrenia patients have personality abnormalities and cognitive deficits that are associated with poor clinical, social, and vocational outcomes. Very few studies have examined relationships between personality and cognitive function, and chronic illness effects may have confounded those studies. In this study personality traits in clinically stable first episode schizophrenia patients (21M, 9F) and psychiatrically healthy controls (38M, 24F) were measured with the NEO-FFI, a self-report measure of neuroticism, extraversion, openness, agreeableness, and conscientiousness. All subjects completed the Information, Digit Span, Vocabulary, and Digit Symbol subtests of the Wechsler Adult Intelligence Scale; and Trails A and B. Standard statistical techniques were used to quantify relationships between personality and symptom levels and/or task performance, and relative contributions of diagnosis and task performance to personality variance. Patients showed elevated mean neuroticism and openness, and reduced mean extraversion, agreeableness and conscientiousness. Task performance and negative symptoms contributed significantly and uniquely to most personality dimensions in patients. Task performance accounted for significant amounts of personality variance even after accounting for diagnosis, and it also contributed to personality variance in controls. These results suggest that cognitive deficits and negative symptoms contribute to consistently observed personality abnormalities in this disorder, and that the contribution of neuropsychological performance to personality variance may be independent of diagnostic classification. Personality abnormalities in schizophrenia may stem from the neurocognitive deficits associated with this disorder, and add to their adverse effects on social and vocational functioning.
Study of persistence in gadolinium oxysulfide x-ray phosphors

There is a need in the x-ray imaging community for phosphors with short persistence (I/I0 < 0.1-0.01% in less than 0.5 ms). Persistence limits a detector's performance by defining the minimum x-ray exposure discernable for a given time after a previous exposure, by ghosting of previous images, and by limiting the dynamic range. The description of the luminescence decay time for any particular phosphor is tedious since the decay time is usually a complicated function of the excitation intensity, the exposure time, the phosphor temperature, and the impurity concentration, as well as the manufacturing procedure. We have characterized commercially available and specially synthesized gadolinium oxysulfide (Gd2O2S) phosphors with a variety of activators in terms of persistence, and relative light output, and discussed their possible usefulness for particular x-ray imaging experiments. We have found that the level of long-term persistence for Gd2O2S x-ray phosphors can differ by more than an order of magnitude solely due to changes in the exposure time. The persistence of these phosphors is characterized as a function of x-ray intensity, exposure time, and, when possible, imppurity concentrations.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Nuclear data sheets for A = 119

Nuclear structure data available through October 1978 are compiled and evaluated. Adopted level and decay properties are given. The bulk of the data is presented pictorially for easy comparison. Experimental details, references, and additional comments, where required, are given in the text. All drawings, tables, and comments are reproduced from the Evaluated Nuclear Structure Data File (ENSDF). Any additions or corrections desired by the users should be addressed to the evaluators for maintenance and updating of the data file.
Acinar cell cystadenocarcinoma of human pancreas

A 7000 g cystic tumor replacing the body and tail of the pancreas was resected in a 64-year-old man. Numerous peritoneal implants confirmed its malignant nature. Light microscopy of both the primary tumor and the implants revealed distinctive cytoplasmic eosinophilia and apical granules. Ultrastructural examination demonstrated numerous zymogen granules and abundant, rough endoplasmic reticulum, which confirmed that the tumor was composed of acinar cells. No mucinous or serous differentiation was detected. We have not found report of a similar tumor.
Discriminative stimulus effects of m-chlorophenylpiperazine as a model of the role of serotonin receptors in anxiety

Serotonin is known to play a role in anxiety. The roles of serotonin reuptake and 5-HT1A receptors have been well characterized, but the contribution of other serotonin receptor subtypes is not as clear. 1-(3-Chlorophenyl)-piperazine (mCPP), which binds non-selectively to a wide range of serotonin receptors, has often been used to produce anxiety in humans and in animal models. Because functional assays indicate that mCPP is significantly more potent at 5-HT2C receptors, it may serve as a tool to investigate the contribution of 5-HT2C receptors to anxiety. This paper reviews the results of behavioral tests using mCPP, including the drug discrimination assay, to model anxiety. Although the discriminative stimulus effects of mCPP do not seem to be a useful screen for general anxiolytics, they do seem to be useful for characterization of the contribution of 5-HT1B and 5-HT2C receptors to the mediation of anxiety-like behaviors.
Variations in the Sun’s Meridional Flow over a Solar Cycle

The Sun's meridional flow is an axisymmetric flow that is generally directed from its equator toward its poles at the surface. The structure and strength of the meridional flow determine both the strength of the Sun's polar magnetic field and the intensity of sunspot cycles. We determine the meridional flow speed of magnetic features on the Sun using data from the Solar and Heliospheric Observatory. The average flow is poleward at all latitudes up to 75 degrees, which suggests that it extends to the poles. It was faster at sunspot cycle minimum than at maximum and substantially faster on the approach to the current minimum than it was at the last solar minimum. This result may help to explain why this solar activity minimum is so peculiar.
Prostate cryoablation using direct transperineal placement of ultrathin probes through a 17-gauge brachytherapy template-technique and preliminary results.

Abstract Objectives. To describe a new surgical approach to third-generation cryoablation of the prostate and present our preliminary results. Methods. The technique is detailed and demonstrated in a Web-based video- clip tutorial. Ninety-two men underwent prostate cryoablation (71 primary ablations, 19 salvage procedures, and 2 repeated cryoablations), using direct transperineal placement of ultrathin probes through a 17-gauge brachytherapy template. Results. No fistulous or major complications were observed. Eight patients (8.3%) had minor complications. In 36 patients, the follow-up period was long enough to permit nadir prostate-specific antigen (PSA) evaluation. In 31 (86%), the nadir PSA was 0.5 ng/mL or less. In 5 patients, the nadir PSA was greater than 0.5 ng/mL. The workup revealed systemic failure in 3 patients and inadequate eradication of the prostate gland in 2 patients. In 18 (86%) of 21 androgen-ablation-naive patients, the nadir PSA was 0.5 ng/mL or less. Nine (43%) had an undetectable nadir PSA and 3 had a nadir PSA of greater than 0.5 ng/mL. Conclusions. A modified, less-invasive approach to cryoablation of the prostate is presented. The preliminary results do not show an increased rate of complications compared with other published series. The clinical outcome data are preliminary. Longer follow-up data are required to draw conclusions concerning efficacy.
The binding interaction between alpha-latrotoxin from black widow spider venom and a dog cerebral cortex synaptosomal membrane preparation.

—The major toxin of black widow spider venom, α-latrotoxin, can be iodinated with 125I with hardly any loss in biological activity. The radioactive toxin could bind specifically to a dog cerebral cortex synaptosomal membrane preparation but not to a dog liver plasma membrane preparation. The bound protein could be recovered from the neuronal membrane preparation in an unchanged form. Non-specific binding was only 6–10% of the total binding. The protein nature of the presumed receptor was indicated by the complete inhibition of the binding by either heating the membrane preparation at 70°C or treating the membrane with trypsin. Pre-incubation with 2%β-mercaptoethanol also completely inhibited the binding, while 70% inhibition was observed after pre-treatment with 10m M-EDTA or EGTA. From plots of the equilibrium binding data, it could be ascertained that the binding is non-cooperative, with an apparent equilibrium dissociation constant, K1, of 1.0 nM. Kinetic data gave an apparent association rate constant of 8.2 × 105 M−1 s−1. Dissociation followed a biphasic exponential with rate constants of 1.4 × 10−3 and 5.2 × 10−5s−1 corresponding to half-lives of 8.2 min and 3.7 h. Possible schemes for the binding interaction were proposed. Based on the present results and on previous results which indicated that α-latrotoxin causes the release of all neurotransmitters and a depletion of the synaptic vesicle population in vertebrate synapses, a hypothetical mechanism of the action for the toxin was proposed, involving the binding of the toxin to a membrane protein receptor which interacts with filamentous proteins linking the synaptic vesicles to the axolemma.
Preference, topology and measure

A symmetric difference metric topology on the collection of binary relations on a countably infinite set provides a new setting for the study of properties of preferences and, as an illustration, is used to lend credence and meaning to some simple intuitions about properties of binary relations. A finite measure on a \(\sigma \)-algebra over the same collection of binary relations is used to provide support for the topological results.
Phonon assisted site-to-site electronic energy transfer between Eu3+ ions in an amorphous solid

Abstract We have investigated the dynamics of phonon assisted electronic energy transfer between Eu3+ ions, experiencing different crystal fields in an amorphous Ca(PO3)2 matrix, using the technique of time-resolved fluorescence line-narrowing (TRFLN). From the concentration and temporal dependence of the transfer rate, the mechanism of the ion—ion electronic coupling has been identified as electric dipole—dipole. Both the excitation wavelength independence and the power law temperature dependence of the transfer rate identify the mechanism of the phonon participation in the transfer process as one involving a two-phonon process, with one-phonon action at each of two coupled ion sites.
Neurite outgrowth from cultured CNS neurons is promoted by inhibitors of protein and RNA synthesis.

We examined the effects of changes caused by the blocking of protein and RNA synthesis on neurite outgrowth from neurons of the central nervous system (CNS) in primary culture. Exposure to cycloheximide and actinomycin-D led to dramatic increases in the length of neurites in cultures of neurons from various rat or chick CNS regions. Inhibitor-induced neurite outgrowth was observed (1) from dopaminergic neurons in mixed cultures of the rat substantia nigra or (2) in pure cultures of rat and chick neurons grown on a polyornithine/laminin substratum. These results suggest that neurite outgrowth from CNS neurons is kept restricted, at least in culture, by the continuous production of a labile neurite-inhibiting protein intrinsic to the neurons, which rapidly decays following inhibition of protein or RNA synthesis. 1994 John Wiley & Sons, Inc.
Anisotropic Damage Effect Tensors for the Symmetrization of the Effective Stress Tensor

Based on the concept of the effective stress and on the description of anisotropic damage deformation within the framework of continuum damage mechanics, a fourth order damage effective tensor is properly defined. For a general state of deformation and damage, it is seen that the effective stress tensor is usually asymmetric. Its symmetrization is necessary for a continuum theory to be valid in the classical sense. In order to transform the current stress tensor to a symmetric effective stress tensor, a fourth order damage effect tensor should be defined such that it follows the rules of tensor algebra and maintains a physical description of damage. Moreover, an explicit expression of the damage effect tensor is of particular importance in order to obtain the constitutive relation in the damaged material. The damage effect tensor in this work is explicitly characterized in terms of kinematic measure of damage through a second-order damage tensor. In this work, tensorial forms are used for the derivation of such a linear transformation tensor which is then converted to a matrix form.
Modeling magnetization transfer using a three-pool model and physically meaningful constraints on the fitting parameters.

Abstract A model for water–macromolecular magnetization transfer is presented which addresses the mechanism of coupling between the hydrogen populations and the extraction of physically meaningful parameters from experimental magnetization transfer data. Both physical exchange between bulk-solvent and site-specific hydration-layer hydrogens and inter molecular magnetic dipolar coupling between these specific hydration-layer-solvent and macromolecular hydrogens are explicitly included, leading to a three-pool model for magnetization transfer. It is shown that the three-pool model is well approximated by a two-pool model for coupling between the bulk-solvent and macromolecular hydrogens when the dipolar-coupled solvent hydrogens are a small fraction of the total solvent, and the solvent–macromolecular coupling constant includes both dipolar magnetic, κ dip , and physical exchange, κ ex , coupling rates. The model is also extended to multiple solvent systems. The model results in a set of coupled equations that predict magnetization transfer spectra as a function of temperature and composition. Physically meaningful constraints on the coupling and relaxation parameters are established for systems in which magnetization transfer has been observed including solvated cross-linked proteins and lipid bilayers. Using parameter estimates based on these constraints, empirical magnetization transfer spectra are well predicted by the model. It is found that the degree of magnetization transfer becomes independent of κ dip and κ ex when these parameters become greater than about 50 s −1 . In the semi-rigid cross-linked protein systems where the mobility of the macromolecular matrix is insensitive to temperature, the magnitude of the observed magnetization transfer is consistent with being limited by the intermolecular dipolar coupling and spin–lattice relaxation in the bulk-solvent phase.
Waves on Inhomogeneous Cylindrical Structures

An analysis is given of some of the basic properties of exponential modes on passive cylindrical structures in which the material constants of the medium vary over the cross section. The bounding surface is assumed to be opaque, in the form of an electric or a magnetic wall; it is therefore always nondissipative. Major consideration is given to structures in which the internal medium is also nondissipative. Each mode is usually a TE = TM mixture. Some of the conventional orthogonality conditions no longer remain valid. In certain circumstances, however, the instantaneous and vector power that flow along the system are still additive among the various modes. Stored and dissipated energies per unit length generally are not additive. The propagation constant for modes on a nondissipative structure cannot be complex. The relation between the direction of the time-average Poynting vector at any point of the cross section, and that of the phase and group velocities, is no longer necessarily conventional, and the space angle between the transverse electric and magnetic fields may vary over the cross section. The field distribution of each mode varies with frequency in a manner which is clarified by physical interpretation.
Electrical and mechanical dyssynchrony in pediatric pulmonary hypertension

Background Electrical and mechanical dyssynchrony are often seen in patients with left ventricular failure. In pediatric pulmonary hypertension (PH), right ventricular failure predominates; however, the prevalence of electrical and/or mechanical dyssynchrony in these patients is unknown. We examined the prevalence of electrical and mechanical dyssynchrony in pediatric PH patients. Methods Medical records (including, functional status, electrocardiograms and echocardiograms) of pediatric PH patients were reviewed. QRS duration z -scores were calculated to determine electrical dyssynchrony. Echo vector velocity imaging was used to calculate the mechanical dyssynchrony index (DI). Results Seventy-seven PH patients (idiopathic pulmonary arterial hypertension [IPAH]: n = 26; congenital heart disease: n = 41; other: n = 10) were studied. Electrical dyssynchrony was seen in 84% ( p z -score of 4.3 (95% CI 3.5 to 5.1). There was no difference between those with IPAH, z = 3.6 (95% CI 2.5 to 4.6), and those without, z = 4.7 (95% CI 3.6 to 5.8). Mechanical dyssynchrony was seen in 76% of patients (mean DI=66 ± 47 vs 18 ± 8 milliseconds in historic controls, p Conclusions Significant electrical and mechanical dyssynchrony is present in pediatric PH patients, regardless of etiology. The overall effect of electrical and mechanical dyssynchrony on outcomes in this patient population is still unknown. Select patients may benefit from resynchronization therapy.
A genetic mutation and gross pathologies in populations of the Triatoma protracta superspecies (Hemiptera: Reduviidae: Triatominae).

A morphological mutation in Triatoma protracta was found to be recessive and not sex linked. Abnormalities in molting, mating trauma and malfunction of the malpighian tubules are discussed. There are 6 figures in the text. Populations discussed in the text are as follows: T. barberi Usinger, 1939; T. peninsularis Usinger, 1940; T. protracta protracta (Uhler, 1894); T. protracta nahuatlae Ryckman, 1962; T. protracta woodi Usinger, 1939; T. protracta zacatecensis Ryckman, 1962; T. sinaloensis Ryckman, 1962.
LOGISTIC REGRESSION AND THE ANALYSIS OF BEGGING AND PARENTAL PROVISIONING

The statistical analysis of parental responses associated with complex offspring begging signals is challenging. The outcome is frequently dichotomous — one nestling receives food first while all others do not, all nestmates potentially affect the outcome, and begging signals are comprised of a variety of cues. Logistic regression is a method that is ideally suited to analyse parental responses (care / no care) relative to offspring cues. I first illustrate the use of simple, univariate logistic regression to examine whether male or female offspring are preferentially fed by their parents, when taking the sex ratio of the entire brood into account. Next, I introduce a model (called Arena) which is specifically designed to analyse the probability of a nestling receiving food given multiple explanatory variables (multivariate), while integrating information from all interacting nestlings (multinomial). Overall, logistic regression models are a statistically rigorous and flexible method to analyse complex parental care data.
Indicators and Standards of Quality Related to Seasonal Employment in the Ski Industry

With a large turnover rate of seasonal employees, the ski industry is in need of a better understanding of indicators of quality related to employee retention. The objectives of the current study were to (1) determine which attributes of a seasonal ski job are best at predicting return to work intentions for both first-year and returning employees, (2) determine which attributes of employment are best at predicting overall job satisfaction for both first-year and returning employees, and (3) determine the optimal levels for six chosen job standards of quality. Distinct differences were found between first-year and returning employees regarding the variables most highly related to both their intentions to return and their overall job satisfaction. Furthermore, social norm curves were utilized to suggest standards of quality related to seasonal ski employment. Specific managerial and theoretical implications are discussed.
Ventriculocordectomy reduces respiratory noise in horses with laryngeal hemiplegia.

Reasons for performing study: Show and performance horse with laryngeal hemiplegia (LH) often present for excessive respiratory noise rather than significant exercise intolerance. Therefore, the goal of surgery in these horses is to reduce respiratory noise but there are no quantitative studies evaluating the effect of any upper-airway surgery in LH-affected horses. Objective: To determine whether bilateral ventriculocordectomy (VC) reduces respiratory noise in exercising horses with laryngeal hemiplegia. Methods: Six Standardbred horses with normal upper airways were used in this study. Respiratory sounds and inspiratory trans-upper airway pressure (P u i ) were measured in all horses before and after induction of LH, and 30, 90 and 120 days after VC. In horses with LH, spectrogram analysis revealed 3 inspiratory sound formants centred at approximately 400, 1700 and 3700 Hz. Inspiratory sound levels (SL) and the sound intensity of the 3 inspiratory formants (F 1 , F 2 , F 3 respectively) were measured using a computer-based sound analysis programme. Results: In LH-affected horses, P u i , inspiratory SL and the sound intensity of F 2 and F 3 were significantly increased compared to baseline values. At 90 and 120 days after VC the sound intensities of F 2 and F 3 returned to baseline values. The P u i and SL, were significantly decreased compared to LH values, but remained different from baseline. Conclusions: VC effectively reduces inspiratory noise in LH-affected horses by 90 days following surgery. Inspiratory trans-upper airway pressures are improved 30 days following VC, but do not return to baseline values. Potential relevance: VC can be recommended as a surgical treatment of LH-affected horses if reduction of respiratory noise is the primary objective of surgery. Further studies are required to determine if variations of the surgical technique used in this study will have similar results.
Network cycle features: Application to computer-aided Gleason grading of prostate cancer histopathological images

Features extracted from cell networks have become popular tools in histological image analysis. However, existing features do not take sufficient advantage of the cycle structure present within the cell networks. We introduce a new class of network cycle features that take advantage of such structures. We demonstrate the utility of these features for automated prostate cancer scoring using histological images. Prostate cancer is commonly scored by pathologists using the Gleason grading system and our automated system based upon network cycle features serves an important need in making this process less labor-intensive and more reproducible. Our system first extracts the cells from the histological images, computes networks from the cell locations and then computes features based upon statistics for the different cycles present in these networks. Using an SVM (Support Vector Machine) classifier on these features, we demonstrate the efficacy of our system in distinguishing between grade 3 and grade 4 prostate tumors. We also show the superiority of our approach over previously developed systems for this problem based upon texture features, fractal features and alternative network features.
Efficient parametric encoding scheme for white matter fiber bundles

We present a novel parametric encoding scheme for efficiently recording white matter fiber bundle information obtained from diffusion tensor imaging. The coordinates of fiber tracts are parameterized using a cosine series expansion. For an arbitrary tract, a 19 degree expansion is found to be sufficient to reconstruct the tract with an average error of about 0.26 mm. Then each tract is fully parameterized with 60 parameters, which results in a substantial data reduction. Unlike traditional splines, the proposed method does not have internal knots and explicitly represents the tract as a linear combination of basis functions. This simplicity in the representation enables us to design statistical models, register tracts and perform subsequent analysis in a more streamlined mathematical framework. As an illustration, we apply the proposed method in characterizing abnormal tracts that pass through the splenium of the corpus callosum in autistic subjects.
Contemporary North American influenza H7 viruses possess human receptor specificity: Implications for virus transmissibility.

Avian H7 influenza viruses from both the Eurasian and North American lineage have caused outbreaks in poultry since 2002, with confirmed human infection occurring during outbreaks in The Netherlands, British Columbia, and the United Kingdom. The majority of H7 infections have resulted in self-limiting conjunctivitis, whereas probable human-to-human transmission has been rare. Here, we used glycan microarray technology to determine the receptor-binding preference of Eurasian and North American lineage H7 influenza viruses and their transmissibility in the ferret model. We found that highly pathogenic H7N7 viruses from The Netherlands in 2003 maintained the classic avian-binding preference for α2–3-linked sialic acids (SA) and are not readily transmissible in ferrets, as observed previously for highly pathogenic H5N1 viruses. However, H7N3 viruses isolated from Canada in 2004 and H7N2 viruses from the northeastern United States isolated in 2002–2003 possessed an HA with increased affinity toward α2–6-linked SA, the linkage type found prominently on human tracheal epithelial cells. We identified a low pathogenic H7N2 virus isolated from a man in New York in 2003, A/NY/107/03, which replicated efficiently in the upper respiratory tract of ferrets and was capable of transmission in this species by direct contact. These results indicate that H7 influenza viruses from the North American lineage have acquired sialic acid-binding properties that more closely resemble those of human influenza viruses and have the potential to spread to naive animals.
Association of 24-Hour Cortisol Production Rates, Cortisol-Binding Globulin, and Plasma-Free Cortisol Levels with Body Composition, Leptin Levels, and Aging in Adult Men and Women

The present study was designed to examine the hypothesis that hypothalamic-pituitary-adrenal axis activity as measured by 24-h cortisol production rate (CPR) and plasma levels of free cortisol is linked to increased body fat in adults, and that increased cortisol levels with aging results from increased CPR. Fifty-four healthy men and women volunteers with a wide range of body mass indexes and ages underwent measurement of CPR by isotope dilution measured by gas chromatography-mass spectroscopy, cortisol-binding globulin, and free cortisol in pooled 24-h plasma, body composition, and leptin. Cortisol clearance rates were determined from the 10-h disappearance curves of hydrocortisone after steady-state infusion in a separate group of lean and obese subjects with adrenal insufficiency. Although CPR significantly increased with increasing body mass index and percentage body fat, free cortisol levels remained independent of body composition and leptin levels due to increased cortisol clearance rates. CPR and free cortisol levels were, however, significantly higher in men than women. In addition, 24-h plasma free cortisol levels were increased with age in association with increased CPR, independent of body size. This increase in hypothalamic-pituitary-adrenal axis activity may play a role in the alterations in body composition and central fat distribution in men vs. women and with aging.