cssi/SciSciGPT-SciSciNet huggingface dataset:
How students invent representations of motion: A genetic account

Abstract The purpose of this paper is to illustrate, through example, a particular approach to understanding how students learn to use scientific and mathematical representations. Much of the work in these fields has been focused on a microanalysis of how students use specific representations, such as line graphs and equations, and on the particular difficulties that students have with these representations. Here, in contrast, I will illustrate an approach that attempts to place students' work with representations in the context of the broader history of their representational experience, and the capabilities that this experience engenders. I refer to this approach as “genetic,” because it attempts to understand episodes of representational learning within the broader context of the genesis of representational competence. I will illustrate this new program by looking at episodes in which students are engaged in the invention of graphical representations of motion. The heart of my analysis will be the identification of what I call constructive resources , basic and somewhat generic resources that contribute to a student's ability to invent representations of motion. The analysis will include a number of core observations. I will argue for the importance of prior experiences with drawing and that some features of drawings are carried over to representations invented by students. I will describe a type of representation I call a temporal sequence that I believe develops from student experience with notational systems. Finally, I will discuss how students' abilities to make use of certain features of elements of a representational display contribute to their ability to invent novel forms.
Experimental Electromechanics of Red Blood Cells Using Dielectrophoresis-Based Microfluidics

This study focuses on electrically coupled mechanics of red blood cells (RBCs) using dielectrophoresis in a microfluidic chamber. When RBCs are exposed to non-uniform alternating current electric fields, they exhibit not only a net motion towards high electric field gradients but also morphological deformation at certain conditions. Through interdigitated electrode arrays, multiple cells can be trapped and stretched simultaneously in response to dielectrophoresis actuations. We utilize this approach to measure mechanical properties of individual RBCs. In addition, this dielectrophoresis platform provides a flexibility in different loading profiles, allowing us to measure both static and dynamic behavior of individual RBCs in response to cyclic stretching-relaxation loading. This approach can potentially lead to insights of the accumulative membrane failure of RBCs in blood and extracorporeal circulations.
Pyridoxine-Dependent Seizures and Intelligence

Clinical manifestations, MRI abnormalities, learning disabilities, and effect of pyridoxine dose on intelligence quotients were studied in 6 definite and 3 possible cases of pyridoxine dependent seizures in children, ages 2.5 to 14 years, seen at Newcastle General Hospital, Newcastle upon Tyne, UK.
Imaging results with a LaBr 3 -based rotational modulator

A gamma-ray imager based on rotational modulation is capable of obtaining significantly better angular resolution than the fundamental geometric resolution defined by the ratio of detector diameter to mask-detector separation. Compared to a standard coded aperture or Compton telescope, a Rotational Modulator (RM) requires a detection plane with only modest spatial resolution, and is consequently less complex. A prototype of this concept developed at LSU features high sensitivity and energy resolution, and a simple readout system. The instrument consists of a single grid of 1.5" wide lead slats separated by 1.5" and spaced 1.2 m in front of an array of 19 1.5" x1" thick LaBr3:Ce scintillators in a concentric circular layout. As the grid rotates, the transmission from a source is modulated on each detector between 0 and 100%. This count profile is cross-correlated with pre-calculated modulation profiles to produce an initial source image. A novel reconstruction technique deconvolves this image with the point-spread function to reduce the effects of noise and resolve sources to within 20', or about 6x better than the geometric resolution of the instrument. We describe this reconstruction technique, and present imaging and spectral results for the RM prototype.
Prioritized Analysis of Inter-App Communication Risks

Inter-Component Communication (ICC) enables useful interactions between mobile apps. However, misuse of ICC exposes users to serious threats such as intent hijacking/spoofing and app collusions, allowing malicious apps to access privileged user data via another app. Unfortunately, existing ICC analyses are largely incompetent in both accuracy and scale. This poster points out the need and technical challenges of prioritized analysis of inter-app ICC risks. In this poster, we propose MR-Droid, a MapReduce-based computing framework for accurate and scalable inter-app ICC analysis in Android. MR-Droid extracts data-flow features between multiple communicating apps and the target apps to build a large-scale ICC graph. Our approach is to leverage the ICC graph to provide contexts for inter-app communications to produce precise alerts and prioritize risk assessments. This process requires large app-pair data, which is enabled by our MapReduce-based program analysis. Our initial extensive experiments on 11,996 apps from 24 app categories (13 million pairs) demonstrate the scalability of our approach.
A method to accelerate creation of plasma etch recipes using physics and Bayesian statistics

Next generation semiconductor technologies like high density memory storage require precise 2D and 3D nanopatterns. Plasma etching processes are essential to achieving the nanoscale precision required for these structures. Current plasma process development methods rely primarily on iterative trial and error or factorial design of experiment (DOE) to define the plasma process space. Here we evaluate the efficacy of the software tool Recipe Optimization for Deposition and Etching (RODEo) against standard industry methods at determining the process parameters of a high density O2 plasma system with three case studies. In the first case study, we demonstrate that RODEo is able to predict etch rates more accurately than a regression model based on a full factorial design while using 40% fewer experiments. In the second case study, we demonstrate that RODEo performs significantly better than a full factorial DOE at identifying optimal process conditions to maximize anisotropy. In the third case study we experimentally show how RODEo maximizes etch rates while using half the experiments of a full factorial DOE method. With enhanced process predictions and more accurate maps of the process space, RODEo reduces the number of experiments required to develop and optimize plasma processes.
Effects of entanglement in optical amplifiers

Entanglement between the signal and the amplifying medium can produce a large amount of decoherence in an ideal optical amplifier even when the gain is arbitrarily close to unity and the added noise is negligible.
Abstract 280: Deficiency of FKBP12 in the Heart Leads to Impaired Contractility and Pregnancy Induced Cardiomyopathy

FK506 Binding Proteins (FKBPs) are a family of cis-trans prolyl isomerases that bind rapamycin and FK506. FKBP12 and 12.6 interact with ryanodine receptors (RyR), homotetrameric transmembrane ion channels that regulate Ca2+ release from the sarcoplasmic reticulum (SR). FKBP12 interacts with RyR1 in skeletal muscle and FKBP12.6 interacts with RyR2 in cardiac muscle to regulate the Ca2+ leak properties of these channels. Recently it has been suggested that FKBP12 also plays a role in regulating RyR2 activity. Using mice with a cardiac specific deficiency in FKBP12, we analyzed the role of FKBP12 in cardiac function. We found that both male and female mice with a α-MyHC Cre/Lox mediated deficiency in FKBP12 in the heart (FKBP12 KD) developed a mild dilated cardiomyopathy, with enlarged left ventricular diameter both during systole and diastole, decreased ejection fraction and decreased fractional shortening. To elucidate the mechanism for these effects we assessed Ca2+ sparks in isolated cardiomyocytes. We found an increase in both Ca2+ spark frequency and spark amplitude in FKBP12 cardiac deficient mice without a change in spark duration. Despite a mild phenotype in adult mice, we found that approximately 25% of all pregnancies (26/106) in the FKBP12 deficient mice resulted in the mothers dying following the birth. Autopsies show that these cardiac specific FKBP12 deficient mice had increased heart weight and significantly dilated ventricles compared to female Cre mice. Our data suggest that a cardiac specific deficiency in FKBP12 leads to the development of pregnancy induced cardiomyopathy. Echocardiography on FKBP12 deficient mice one day after giving birth found that there was no significant difference in ejection fraction or fractional shortening compared to α-MyHC Cre control mice. FKBP12 deficient females, however, had larger hearts and 50% (2/4) displayed heart failure and died. In conclusion, we show that FKBP12 does indeed alter Ca2+ handling in the heart and that a loss of FKBP12 leads to the development of pregnancy induced cardiomyopathies in females.
Measurements and Simulations of Ultralow Emittance and Ultrashort Electron Beams in the Linac Coherent Light Source

The Linac Coherent Light Source (LCLS) is an x-ray Free-Electron Laser (FEL) project presently in a commissioning phase at SLAC. We report here on very low emittance measurements made at low bunch charge, and a few femtosecond bunch length produced by the LCLS bunch compressors. Start-to-end simulations associated with these beam parameters show the possibilities of generating hundreds of GW at 1.5 {angstrom} x-ray wavelength and nearly a single longitudinally spike at 1.5 nm with 2-fs duration.
Electroencephalography (EEG) classification of cognitive tasks based on task engagement index

The application of autonomous systems is on an increase, and there is the need to optimize the fit between humans and these systems. While operators must be aware of the autonomous systems dynamic behaviors, the autonomous systems must in turn base their operations, among other things, on an ongoing knowledge of operators' cognitive state, and its application domain. Psychophysiology allows for the use of physiological measurements to understand an operators behavior by noninvasively recording peripheral and central physiological changes while the operator behaves under controlled conditions. Electroencephalography (EEG) is a psychophysiological technique for studying brain activation. In the present study, EEG task engagement index, defined as the ratio of beta to (alpha + theta), are used as inputs to an artificial neural network (ANN) to allow identification and classification of mental engagement. Six separate feedforward ANN with single hidden layer trained by backpropagation were designed to classify five mental tasks for each of six participants. The average classification accuracy across the six participants was 88.67 %. The results show that differences in cognitive task demand do elicit different degrees of mental engagement, which can be measured through the use of the task engagement index.
Lessons from Forty Years as a Literacy Educator: An Information Literacy Narrative

This article summarises the author’s evolution as a writing instructor toward a career as a librarian teaching information literacy and finally as a scholar and researcher studying information literacy as an academic subject. Changes in writing pedagogy are explored as they relate to changes in the author’s instructional practices and how they underlie an understanding of information literacy as a form of literacy practice closely related to writing. Questions about the future of information literacy under current management philosophy are presented.
Prospective measures of competitive balance application to money lines in the national hockey league

The authors have previously introduced the concept of utilizing point spreads to measure competitive balance in professional sports and a methodology for doing so. They assessed competitive balance...
Evolution and Language: Overview

The complex relationship between general evolution and its application to language is discussed from two points of view. The first concerns the basic similarity of structure between biological and linguistic classification. A classificational hierarchy is in both cases explained as the outcome of a process of evolutionary change and divergence from common originals through time rather than a succession of creationist acts. The second major topic is the basic role of language in the evolution of communication in general.
A General-Purpose System for Simulating and Training Complex Diagnosis and Troubleshooting Tasks

As military hardware becomes increasingly complex and costly, the suitability of using the prime equipment to meet the bulk of training requirements diminishes. At the present time, “general purpose” trainers can be developed which have the capability of providing realistic experience in operating or maintaining the prime equipment. Such trainers not only can simulate the functional and physical characteristics of the particular prime equipment, but they can deliver tutorial and special problem assistance when required by individual students; they can rapidly select, initiate, and administer problems based upon individual student performance; and they can record detailed performance data for instructor use. Furthermore, it is possible to provide “universal” applicability of both hardware and software, such that the trainer can be rapidly switched to a different prime equipment once the “courseware” is produced.
Real-Time Surveys Reveal Important Safety Risks During Interhospital Care Transitions for Neurologic Emergencies.

Critically ill patients may be exposed to unique safety threats as a result of the complexity of interhospital and intrahospital transitions involving the emergency department (ED). Real-time surveys were administered to clinicians in the ED and neuroscience intensive care unit of a tertiary health care system to assess perceptions of handoff safety and quality in transitions involving critically ill neurologic patients. In all, 115 clinical surveys were conducted among 26 patient transfers. Among all clinician types, 1 in 5 respondents felt the handoff process was inadequate. Risks to patient safety during the transfer process were reported by 1 in 3 of respondents. Perceived risks were reported more frequently by nurses (44%) than physicians/advanced practice providers (28%). Real-time survey methodology appears to be a feasible and valuable, albeit resource intensive, tool to identify safety risks, expose barriers to communication, and reveal challenges not captured by traditional approaches to inform ...
Physiology of Hemostasis

Disorders of hemostasis and thrombosis arise from the loss of an elegant balance of activation and inhibition among the proteins, the cells in the intravascular compartment, and the parent vessel that carries these participants. Tipping the balance one way or another leads to abnormal bleeding or clotting. Hemostasis, that is, the cessation of bleeding, consists of protein, cellular, and vessel components. The surface of neutrophils, platelets, and endothelial cells are the main loci where hemostasis or thrombosis initiates. The protein components consist of three systems: coagulation, fibrinolysis, and anticoagulant. In physiologic hemostasis when there is a bleeding risk, hemostasis is initiated by tissue factor and factor VIIa. In disease (pathophysiologic states), bleeding cessation can be induced by contact activation of factor XII. Alternatively, in both physiologic and pathophysiologic states, vessel occlusion or thrombosis arises from both expression of tissue factor and factor VIIa or activation of factor XII upon contact with various physiologic or pathophysiologic anionic biologic surfaces. The goal of hemostasis is to generate thrombin in a kinetically fast manner to stop bleeding in a sufficient manner without complete vessel occlusion and downstream tissue ischemia. Two important coagulation protein assemblies, called tenase and prothrombinase, contribute to the rate of thrombin generation that is directly measurable with relatively simple techniques. Three major anticoagulant systems, protein C and S, antithrombin, and tissue factor pathway inhibitor, limit the extent of thrombin formation in vivo. These reactions occur in the intravascular compartment and on or about cell surfaces.
Wisdom of Crowds and the Market’s Response to Earnings News: Evidence From the Geographic Dispersion of Investors

The wisdom of crowds suggests that groups reach more informed decisions when its members are more diversely informed because, collectively, they have more information which complements the group's assessments and decisions. I examine whether the response to earnings news is more complete and timely when investors are more diversely informed. I measure how diversely informed firms’ investors are using the amount of dispersion in their locations, estimated using the locations of the requests for firms’ filings from EDGAR. I find greater abnormal turnover in the three-day window around announcements for firms that have a greater dispersion of requests, consistent with diverse investors having more disagreement in their assessments of earnings news. My analysis of the price response also suggests a more complete and timely response to announcements, consistent with more complementary information being incorporated in the response to earnings news in a timelier manner when investors are more diversely informed.
A Synopsis of Pediatric Patients With Hepatoblastoma and Wilms Tumor: NSQIP-P 2012-2016.

Abstract Background Hepatoblastoma and Wilms tumor are the most common primary liver and kidney tumor in children, respectively, and little is documented about patient outcomes in the immediate perioperative period. The aim of this study was to analyze the short-term outcomes of pediatric patients after surgical resection for hepatoblastoma and Wilms tumor. Methods We queried the 2012-2016 ACS National Surgical Quality Improvement Program-Pediatric (NSQIP-P) database for patients with hepatoblastoma who underwent liver resection and patients with Wilms tumor who underwent a partial or total nephrectomy. Patient demographics, preoperative, intraoperative, and postoperative characteristics were analyzed. Multivariate logistic regression was used to determine independent risk factors for unplanned reoperations. Results There were a total of 189 patients with hepatoblastoma and 586 patients with Wilms in National Surgical Quality Improvement Program-Pediatric. The mean age of patients with hepatoblastoma was 3.1 y and 4.2 y in the Wilms group. Nine percent (n = 17) of patients underwent an unplanned reoperation after hepatectomy, and 4.1% (n = 24) of patients with Wilms experienced an unplanned reoperation. Over half of patients with hepatoblastoma (59.8%, n = 113) and 29.7% (n = 174) patients with Wilms tumor received a blood transfusion in the perioperative period. Patients in both groups demonstrated low rates of surgical site infections, but 6.3% (n = 12) of hepatoblastoma patients showed evidence of sepsis. Conclusions This study will allow providers to more effectively counsel families of the common morbidities in the associated perioperative period following surgical resection of either solid tumor type including the substantial risk of blood transfusion.
Responsive neurostimulation targeting anterior thalamic nucleus in generalized epilepsy

Responsive neurostimulation (RNS) has emerged as an adjunctive treatment modality for patients with intractable focal epilepsy who are not surgical candidates or have more than one ictal onset focus. We report a 34-year-old patient with intractable, childhood-onset, genetic generalized epilepsy (GGE) with tonic, atonic, myoclonic and absence seizures treated with RNS. Strip electrodes over the right posterior frontal cortex and depth electrodes placed in the right anterior nucleus were used for event detection and responsive stimulation. Two-year follow-up revealed 90-95% clinical seizure reduction. This case suggests that refractory GGE may be effectively treated with RNS targeting thalamocortical networks.
Relationships and Retaliation in the #MeToo Era

In this #MeToo era, so much important work is being done (and so many stories are being told and listened to) but very little of the work focuses on retaliation. And none of it focuses on situations where the fear of retaliation is not necessarily job loss (although that certainly happens) but rather, is the fear of harming workplace relationships. This article will use a real-life story of harassment to demonstrate how much workplace relationships matter (especially to women) and how the fear of harming those relationships often affects an employee’s willingness to report harassment. Thus, this article argues for reforms surrounding harassment and retaliation law that recognize this reality. Right now, courts penalize victims of harassment for not reporting harassment soon enough because they feared harming their workplace relationships; or, when they do report, courts penalize them by holding that the relationship-based harm they experienced after reporting wasn’t a real harm worthy of a remedy. The reasoning of these courts is that reasonable employees would not and should not be deterred from reporting harassment because they fear relationship-based harms. And yet, most of the empirical evidence tells us that the opposite is true—that reasonable employees (sometimes men, but especially women) often do avoid reporting because of fear of harming their relationships in the workplace. The law should reflect this reality.
Splitting tower of Hanoi into odd even disks

This paper addresses a Tower of Hanoi related problem. The problem is to split a tower of disks into a tower of odd numbered disks and a tower of even numbered disks. There are three poles and the standard rules of disk movement apply. Two algorithms to solve the problem are presented. The first algorithm is easy to design and analyze. It uses direct recursion. The second algorithm is a better algorithm but it is more complex. It involves two other splitting problems. The three splitting problems are solved by three functions which call each other in a circular order resulting in indirect recursion. Analysis of the three coupled recursive functions involves three simultaneous recurrence equations which are solved iteratively.
Performance Study of a GAA-GAA Coexistence Scheme in the CBRS Band

The General Authorized Access (GAA) users in the Citizens Broadband Radio Service (CBRS) band are the lowest priority users who not only have to make sure that they do not cause harmful interference to the higher tier users but also must cooperate with each other to minimize potential interference among themselves. Thus, efficient GAA coexistence scheme is essential for operation of GAA users and to obtain high spectrum utilization. Towards this goal, the Wireless Innovation Forum (WInnForum) has recommended three schemes to facilitate coexistence among the GAA users. To the best of our knowledge, there is no performance study on any of these schemes available in the public domain. In this paper, we study performance of one of these schemes (called Approach 1). We choose two actual locations in the USA around which our study is conducted using actual terrain and land cover data of the continental USA. We evaluate performance of the scheme at different deployment densities, using different propagation models and with different mix of CBRS devices (CBSDs) at those two locations. We provide some interesting insights into the bandwidth allocation process and performance of Approach 1 in terms of mutual interference.
Condom-Associated Erectile Function, But Not Other Domains of Sexual Functioning, Predicts Condomless Insertive Anal Sex Among Young Men Who Have Sex with Men

Condoms effectively prevent against HIV, especially when used in conjunction with biomedical strategies such as PrEP and viral suppression. However, consistent use of condoms in the real world has been a continual health promotion challenge, even among populations at highest risk, such as young men who have sex with men (YMSM). Inconsistent condom use may be related to poor sexual functioning, but limited research exists. The analytic sample comprised 688 racially diverse YMSM aged 16–29 (M = 22.9 years) living in Chicago, IL (19.2% living with HIV). Using multivariable logistic regression, we examined longitudinal associations between condom-associated sexual functioning (erectile function, orgasm satisfaction, global satisfaction, and anal discomfort) and condomless insertive anal sex (CIAS) and condomless receptive anal sex (CRAS) 6 months later. CIAS at Time 2 was associated with condom-associated erectile function at the bivariate and multivariable levels, even after controlling for CIAS at Time 1 (p < .05). Condom-associated erectile function, orgasm satisfaction, and global satisfaction predicted Time 2 CRAS in bivariate models, but none remained significant in the multivariable models. Age, having had a serious partner in the past 6 months, and HIV/PrEP status at Time 2 were significant predictors of CIAS/CRAS in some but not all models. Future interventions to improve consistent condom use should specifically highlight information and skills on how to use condoms within real-world contexts rather than from a clinical perspective. Our results also support the importance of biomedical strategies for those who have continued problems with sexual functioning when using condoms.
Imaging of Brainstem Lesions

Brainstem lesions can arise from the midbrain, pons, or medulla. Oftentimes, these lesions will affect adjacent nuclei/pathways or result in mass-effect within the posterior fossa. Imaging of brainstem lesions can be achieved by utilizing multiple modalities, each of which offer modality-specific advantages and disadvantages. Imaging may include magnetic resonance imaging (MRI), computed tomography (CT), and/or positron emission tomography (PET) imaging. Ultrasound imaging may also be utilized to evaluate the posterior fossa of newborns. The density of the skull base typically presents an obstacle for imaging of the posterior fossa. MRI is the modality of choice for the evaluation and characterization of brainstem lesions. Imaging characteristics of different brainstem lesions can provide invaluable pretreatment information to aid in the diagnosis, assess impact on adjacent structures, and assist in treatment planning. When evaluating neoplastic lesions, imaging may also serve to distinguish between neoplastic progression versus development of post-treatment changes. In this chapter, we provide an overview of the typical imaging appearance of common neoplastic and non-neoplastic lesions within the brainstem.
Dissipative Pulsar Magnetosphere

Dissipative axisymmetric pulsar magnetosphere is calculated by a direct numerical simulation of the Strong-Field Electrodynamics equations. The magnetic separatrix disappears, it is replaced by a region of enhanced dissipation. With a better numerical scheme, one should be able to calculate the bolometric lightcurves for a given conductivity.
A COMPARISON OF STOCHASTIC MESH CELL VOLUME COMPUTATION STRATEGIES FOR THE RANDOM RAY METHOD OF NEUTRAL PARTICLE TRANSPORT

The random ray method is a recently developed neutron transport method that can be used to perform efficient full-core, general-purpose, high-fidelity 3D simulations of nuclear reactors. While Tramm et al. have so far documented the new random ray algorithm in several publications, one critical detail has not yet been published: how to best determine the volume of each source region (or cell) of the simulation. As the “true” analytical constructive solid geometry cell volumes are typically not known a priori they must be computed by the application at runtime, which is not straightforward in TRRM as different rays are used each power iteration such that the sampled volume of each cell also changes between iterations. In the present study, we analyze two different on-the-fly stochastic methods for computing the cell volumes and quantify their impacts on the accuracy of scalar flux estimates. We find that the “na¨ive” stochastic volume estimator (which arises naturally from the derivation of the Method of Characteristics), is highly biased and can result in over 1,000 pcm error in eigenvalue. Conversely, we find that the “simulation averaged” estimator is unbiased and is therefore equivalent to the use of analytical cell volumes even when using a coarse ray density. Thus, the new simulation averaged method is a critical (and as yet undocumented) component of the TRRM algorithm, and is therefore vital information for those in the reactor physics community working to implement random ray solvers of their own.
The Values We Share

tain moral principles, such as respect for human rights, we also witness a major theoretical challenge to the notion that anything can ever be universal. Wisely, the editors of Prospects for a Common Morality choose to address this paradox tentatively. Their aim is not to establish what they call "a party line" on either the postmodern or the human rights side. It is rather to ask some of our more thoughtful philosophers and theologians to reflect on the issues involved.
Fluorescence measurement of changes in intracellular calcium induced by excitatory amino acids in cultured cortical astrocytes

Population response of [Ca2+]i in cultured cortical astrocytes to excitatory amino acids was measured at room temperature using the calcium-sensitive dye fura-2. Quisqualic acid (QA), glutamate (Glu), and kainic acid (KA) caused a peak increase in [Ca2+]i in the order QA greater than Glu greater than KA. No response to N-methyl-D-aspartic acid (NMDA) was observed whether or not Mg2+ was present externally. Both QA and Glu (100 microM) frequently elicited a decaying oscillatory [Ca2+]i response during sustained agonist application; the period of oscillations initially was 23.5 sec and increased as the response was damped. Comparatively, the [Ca2+]i response to KA was nonoscillatory. Both responses to Glu and KA were reduced slightly by antagonist gamma-D-glutamylaminomethyl-sulfonic acid (1 mM), but virtually were abolished by kynurenic acid (3 mM). Replacement of external Na+ by choline had no significant effect on the Glu response. Removal of external Ca2+ reduced the peak response to QA, Glu, and KA to 40, 34, and 18%, respectively; and markedly reduced the degree of QA- and Glu-induced [Ca2+]i oscillations. Pretreatment with phorbol esters, a potent activator of protein kinase C, blocked the [Ca2+]i response to Glu but not KA. It is concluded that cortical astrocytes express Glu receptors of the non-NMDA type in culture and that receptor activation leads to Ca2+ influx and release of internal Ca2+. Mobilization of Ca2+ apparently occurs via the known Glu-mediated hydrolysis of inositol lipids, which may come under negative-feed-back control by protein kinase C activation. Oscillatory [Ca2+]i signaling offers the possibility of a dynamic population response in an electrically coupled glial network.
Enteral compared with parenteral nutrition: a meta-analysis

Background: The difference in outcomes in patients is unclear when 2 types of enteral nutrition, ie, tube feeding and conventional oral diets with intravenous dextrose (standard care), are compared with parenteral nutrition. Objective: We reviewed systematically and aggregated statistically the results of prospective randomized clinical trials (PRCTs) to examine the relations among the nutrition interventions, complications, and mortality rates. Design: We conducted a MEDLINE search for PRCTs comparing the effects of enteral and parenteral nutrition in adults. Two different people abstracted data for the method and outcomes separately. We used fixed-effects meta-analysis technique to combine the relative risks (RRs) of the outcomes of infection, nutrition support complications, other complications, and mortality. Results: Twenty-seven studies in 1828 patients met the study criteria. Aggregated results showed a significantly lower RR of infection with tube feeding (0.64; 95% CI: 0.54, 0.76) and standard care (0.77; 95% CI: 0.65, 0.91). A priori hypotheses showed a lower RR of infection with tube feeding than with parenteral nutrition, regardless of nutritional status, presence of cancer, year of study publication, or quality of the study method. In studies in which participants had high rates of protein-energy malnutrition, there was a significantly higher risk of mortality (3.0; 95% CI: 10.9, 8.56) and a trend toward a higher risk of infection with standard care than with parenteral nutrition (1.17; 95% CI: 0.88, 1.56). Conclusions: Tube feeding and standard care are associated with a lower risk of infection than is parenteral nutrition; however, mortality is higher and the risk of infection tends to be higher with standard care than with parenteral nutrition in malnourished populations.
Applications of Solid-State Magic Angle NMR Spectroscopy to Fiber Reinforced Composites

The solid-state NMR techniques of cross polarization (CP), high power proton decoupling and magic angle sample spinning allow one to study the binding of coupling agents to silica surfaces, γ-mercaptopropyltrimethoxysilane (y -MPTS), γ-aminopropyltriethoxy-silane (γ-APS), γ-glycidoxypropyltrimethoxysilane (γ-GPS), γ-metha-cryloxypropyltrimethoxysilane (γ-MPS) and vinyltriethoxysilane (VTES) were the organosilanes utilized on high-surface-area silica. High resolution solid-state 13C NMR spectra were obtained for coupling agents adsorbed on silica surfaces and for the corresponding coupling agents condensed as bulk polymers. Chemical shifts and line widths of the resonances of the chemically modified silicas are compared to those resonances arising from the bulk organosilanes. The spectra confirm chemical binding of the coupling agent to the silica surface. A graphite-filled epoxy is characterized in terms of molecular motion. In this study 13C spin-lattice relaxation times in the rotating frame of reference (T1ρ) were obtained for the composite.
Pulse time and agarose concentration affect the electrophoretic mobility of cccDNA during electrophoresis in CHEF and In FIGE

Abstract Circular DNAs have been shown to migrate in an unusual manner during field inversion gel electrophoresis (FIGE) and orthogonal field alternating gel electrophoresis (OFAGE). We studied the effect of varying pulse time and agarose concentration on the electrophoretic mobility of supercoiled (ccc) DNAs ranging from 2 kbp to 16 kbp during FIGE and contoured homogeneous electric fields (CHEF). Both supercoiled and linear molecules display a minimum mobility as a function of pulse time in a CHEF apparatus. Linear and cccDNAs of the same size are differently affected by pulse time. Pulse-time dependence was observed for cccDNAs in both systems. Pulse-time dependence in FIGE is very small at a 1.0% agarose concentration, but is pronounced in 0.8% or 1.2% gels.
Physiological differences between the alpha and beta ryanodine receptors of fish skeletal muscle

Two isoforms of the sarcoplasmic reticulum Ca2+ release channel (ryanodine receptor or RYR) are expressed together in the skeletal muscles of most vertebrates. We have studied physiological properties of the two isoforms (alpha and beta) by comparing SR preparations from specialized fish muscles that express the alpha isoform alone to preparations from muscles containing both alpha and beta. Regulation of channel activity was assessed through [3H]ryanodine binding and reconstitution into planar lipid bilayers. Distinct differences were observed in the calcium-activation and -inactivation properties of the two isoforms. The fish alpha isoform, expressed alone in extraocular muscles, closely resembled the rabbit skeletal muscle RYR. Maximum [3H]ryanodine binding and maximum open probability (Po) of the alpha RYR were achieved from 1 to 10 microM free Ca2+. Millimolar Ca2+ reduced [3H]ryanodine binding and Po close to zero. The beta isoform more closely resembled the fish cardiac RYR in Ca2+ activation of [3H]ryanodine binding. The most prominent difference of the beta and cardiac isoforms from the alpha isoform was the lack of inactivation of [3H]ryanodine binding and Po by millimolar free Ca2+. Differences in activation of [3H]ryanodine binding by adenine nucleotides and inhibition by Mg2+ suggest that the beta and cardiac RYRs are not identical, however. [3H]ryanodine binding by the alpha RYR was selectively inhibited by 100 microM tetracaine, whereas cardiac and beta RYRs were much less affected. Tetracaine can thus be used to separate the properties of the alpha and beta RYRs in preparations in which both are present. The distinct physiological properties of the alpha and beta RYRs that are present together in most vertebrate muscles support models of EC coupling incorporating both directly coupled and Ca(2+)-coupled channels within a single triad junction.
Theorems of electrochemical mass transport in dilute solutions of mixtures of electrolytes, including weak electrolytes and hydrolysis reactions

The Nernst-Planck mass-transport treatment is extended to electrolytic multicomponent systems including mixtures of strong electrolytes, weak electrolytes, and hydrolysis reactions, in dilute, stagnant solutions. The extension is presented in the form of theorems of electrochemical mass transport. The validity and usefulness of the theorems have been demonstrated in their application to two important and complex systems, namely, electrodialysis at larger than limiting currents, and corrosion of ferrous alloys in waters at high temperature and pressure. These applications are briefly summarized here. The theorems are useful for treatment of electrochemical mass transport in boundary layers that can be approximated by stagnant layers. The theorems should prove useful to workers and students of electrochemical transport problems, especially for problems involving electrolytic multicomponent and heterogeneous systems.
Spectral imaging of clouds using a digital array scanned interferometer

Abstract Spectral images of various cloud fields have been made from the ground using a prototype imaging interferometer. The instrument, called DASI (digital array scanned interferometer), is under development as an alternative technique for terrestrial remote sensing. Our paper describes the unusual characteristics of DASI's that make them promising candidates for both ground and aircraft based measurements of clouds. These characteristics include superior signal-to-noise potential, design simplicity and compactness. The prototype DASI had a wavelength sensitivity range of 4550–9090 cm −1 (1.1–2.2 μm), a spectral resolution of 300 cm −1 , a spatial field of view of 5 degrees, and 256 transverse spatial elements for each exposure frame with exposure rates up to 1 frame/s. Spectrally resolved images of cirrus and cumulus clouds over the San Francisco Bay area were obtained by multiple frame scanning over the field of view. The DASI measurements are compared with radiative transfer calculations using LOWTRAN-7. Modification of the LOWTRAN code was necessary so that high spectral resolution data for ice optical properties could be used. With these modifications, the agreement between measured and model results is good in some cases. However, quantitative interpretation of these preliminary measurements was not generally possible because of various sources of uncertainty. Finally, a discussion is given on the potential applications and science yields of DASI instruments in the framework of coordinated field missions such as project FIRE. Such applications include the use of ground and airborne based DASI's to retrieve microphysical properties of clouds and to investigate current problems in atmospheric radiation.
COSTS AND BENEFITS OF WITHIN‐GROUP SPATIAL POSITION: A FEEDING COMPETITION MODEL

ABSTRACT An animal’s within‐group spatial position has several important fitness consequences. Risk of predation, time spent engaging in antipredatory behavior, and feeding competition can all vary with respect to spatial position. Previous research has found evidence that feeding rates are higher at the group edge in many species, but these studies have not represented the entire breadth of dietary diversity and ecological situations faced by many animals. In particular, the presence of concentrated, defendable food patches can lead to increased feeding rates by dominants in the center of the group that are able to monopolize or defend these areas. To fully understand the tradeoffs of within‐group spatial position in relation to a variety of factors, it is important to be able to predict where individuals should preferably position themselves in relation to feeding rates and food competition. A qualitative model is presented here to predict how food depletion time, abundance of food patches within a grou...
Relation of desert pupfish abundance to selected environmental variables in natural and manmade habitats in the Salton Sea basin

We assessed the relation between abundance of desert pupfish, Cyprinodon macularius, and selected biological and physicochemical variables in natural and manmade habitats within the Salton Sea Basin. Field sampling in a natural tributary, Salt Creek, and three agricultural drains captured eight species including pupfish (1.1% of the total catch), the only native species encountered. According to Bray–Curtis resemblance functions, fish species assemblages differed mostly between Salt Creek and the drains (i.e., the three drains had relatively similar species assemblages). Pupfish numbers and environmental variables varied among sites and sample periods. Canonical correlation showed that pupfish abundance was positively correlated with abundance of western mosquitofish, Gambusia affinis, and negatively correlated with abundance of porthole livebearers, Poeciliopsis gracilis, tilapias (Sarotherodon mossambica and Tilapiazillii), longjaw mudsuckers, Gillichthys mirabilis, and mollies (Poecilia latipinnaandPoecilia mexicana). In addition, pupfish abundance was positively correlated with cover, pH, and salinity, and negatively correlated with sediment factor (a measure of sediment grain size) and dissolved oxygen. Pupfish abundance was generally highest in habitats where water quality extremes (especially high pH and salinity, and low dissolved oxygen) seemingly limited the occurrence of nonnative fishes. This study also documented evidence of predation by mudsuckers on pupfish. These findings support the contention of many resource managers that pupfish populations are adversely influenced by ecological interactions with nonnative fishes.
Sexually Transmitted Diseases: Current and Emerging Concerns

Sexually transmitted diseases (STDs) are epidemic today, with the highest prevalence being among adolescents and young adults. If any decrease in incidence is to occur, nurses must make a determined effort to identify at-risk individuals and groups and empower them through teaching and counseling about strategies of primary and secondary prevention. Current and emerging concerns that make prevention of STDs difficult include such problems as the huge reservoir of infected individuals with no symptoms, the synergy between STDs and human immunodeficiency virus infections, and the particular vulnerability of women to STDs based on their biology. A holistic approach to care that is sensitive to the age, race, culture, and core group characteristics is essential for effective prevention efforts.
Sodium-dependent uptake of [3H]scyllo-inositol by Tetrahymena: incorporation into phosphatidylinositol, phosphatidylinositol-linked glycans, and polyphosphoinositols.

[3H]Scyllo-inositol was taken up by Tetrahymena cells through a sodium-dependent pathway wherein unlabeled scyllo- and myo-inositol competed for uptake. d-Glucose was a competitor of [3H]myo-inositol uptake, but did not appear to compete for [3H]scyllo-inositol uptake. Transport of [3H]scyllo- and [3H]myo-inositol was inhibited when sodium was removed from the labeling buffer and by phlorizin, an inhibitor of sodium-dependent transporters. Cytochalasin B, an inhibitor of facilitated glucose transporters, had no significant effect on inositol transport. Internalized [3H]scyllo-inositol was readily incorporated intact into phosphatidylinositol, phosphatidylinositol-linked glycans, and polyphosphoinositols. Distribution of [3H]scyllo- and [3H]myo-inositol radioactivity into individual polyphosphoinositols was found to differ.
Relative sea-level history and isostatic rebound in Newfoundland, Canada

The island of Newfoundland, Canada, is situated close to the former margins of the Laurentide ice sheet. The post-glacial sea-level history is complex, dominated by the effects of an ice-marginal crustal forebulge produced by isostatic deformation of the lithosphere. Marine fossils found above present sea-level can be 14C dated, and examination of the temporal and geographical distribution of these 14C dates in combination with geomorphological indicators of past sea-levels indicates regional trends of relative sea-level change. For most of the island (apart from the Northern Peninsula) no samples have been recovered that date younger than 8000 BP. suggesting that sea-level lay below the present one in these areas for the last 8000 years. The same areas commonly show geomorphological evidence for stands of sea-level both above and below present sea-level. This evidence is interpreted as showing that over most of Newfoundland, following deglaciation, sea-level fell to below present levels, and subsequently rose to the modern level. Exceptions to this pattern are the north of the Northern Peninsula, which shows a history of continuous emergence, or a more complex pattern of sea-levels falling below present, subsequently rising above present, and currently falling; and the northeast Avalon Peninsula, which may have had sea-levels below present throughout post glacial times. This pattern of relative sea-level change is interpreted as being mostly due to isostatic recovery, with the main factor being northerly migration of the forebulge. Mapping the time at which sea-level fell below the present level allows estimation of the rate of northerly migration and collapse of the forebulge at between 4.5 and 11 km/100 years; this is considerably faster than previous estimates.