cssi/SciSciGPT-SciSciNet huggingface dataset:
Words with friends: writing collaboratively online

Author(s): Boellstorff, T; Nardi, B; Pearce, C; Taylor, TL | Abstract: Tom Boellstorff, Bonnie Nardi, both from University of California, Celia Pearce, Georgia Institute of Technology and T. L. Taylor from Massachusetts Institute of Technology, wrote Ethnography and Virtual Worlds: A Handbook of Method. The Handbook had been written as an entirely collaborative document, with a single authorial voice. They achieved their goal with a mix of synchronous and asynchronous collaboration methods. Aside from a small number of face-to-face meetings, they spent many hours in email and Skype discussing how best to present the principles of ethnographic research, how to clear up misconceptions regarding its scope and value, and how to reach a wide audience. Their breakthrough occurred when they realized that rather than propose an edit in a comment box, they could make the proposed edit in the text and paste the old version in a comment box. While they used asynchronous collaboration primarily during the early phases of composing the manuscript, they did return to asynchronous collaborating after the synchronous phase, in the final stages of writing.
Role of Duplicate Genes in Robustness against Deleterious Human Mutations

It is now widely recognized that robustness is an inherent property of biological systems [1],[2],[3]. The contribution of close sequence homologs to genetic robustness against null mutations has been previously demonstrated in simple organisms [4],[5]. In this paper we investigate in detail the contribution of gene duplicates to back-up against deleterious human mutations. Our analysis demonstrates that the functional compensation by close homologs may play an important role in human genetic disease. Genes with a 90% sequence identity homolog are about 3 times less likely to harbor known disease mutations compared to genes with remote homologs. Moreover, close duplicates affect the phenotypic consequences of deleterious mutations by making a decrease in life expectancy significantly less likely. We also demonstrate that similarity of expression profiles across tissues significantly increases the likelihood of functional compensation by homologs.
Some aspects of the stratospheric Cl-ClO-Cl cycle - Possible roles of ClO, ClNO3 and HOCl

The possible inhibitory effect of excited ClO produced during chlorine-sensitized ozone decomposition on the stratospheric Cl-ClO-Cl cycle is investigated. Collisional deactivation of excited ClO is discussed, chemical reactions involving excited ClO are examined, and the possible roles of HO2 and NO2 in weakening the Cl-ClO-Cl cycle are evaluated. It is noted that the formation of HOCl through a reaction between ClO and HO2 implies that the Cl-ClO-Cl cycle has not been completed.
Surface and pulpal temperature comparison of tooth whitening using lasers and curing lights

Chemical action of bleaching agents applied to tooth surface is accelerated by increase in temperature. This in vitro study measured the temperature rises on the surface and in the pulp of teeth during whitening using a diode laser, a plasma arc curing (PAC) light and conventional curing lights. Extracted, non-carious single-rooted teeth were exposed to PAC light and laser at times ranging from 10 to 60 seconds and energy ranges of 2 W, 4 W, and 6 W, and to low-intensity curing lights from 1 to 4 minutes. Maximum temperature rises were analyzed for both pulpal and surface temperature. Diode laser exposures at 2 W for all times and at 4 watts for 10 seconds and PAC light exposures at 10 seconds all produced acceptably safe pulpal rises equivalent to conventional light-curing exposures. Exposures at these settings also attained surface temperature rises that were significantly higher than those using conventional light-curing. The diode laser demonstrated bleaching results equivalent to the PAC light, and both were achieved in significantly less times than conventional light- curing.
Evaluation of a CCD star camera at Table Mountain Observatory

An instrument has been designed to demonstrate 5 arc second autonomous, all-stellar attitude determination on a NASA Spartan spacecraft. The instrument includes a CCD star camera that provides centroid measurements of up to 5 simultaneous star images with 10 frames of data per s. The performance of the camera and processing techniques have been studied in an extensive test program including star measurements taken under realistic conditions at the Jet Propulsion Laboratory Table Mountain Observatory. Results of these tests are presented and compared to laboratory and simulation data. At slue rates less than 0.1 deg/s the camera accuracy was found to vary from 5 to 15 arc seconds per image, depending on star magnitude. Q
Flavonol-rich fractions of yaupon holly leaves (Ilex vomitoria, Aquifoliaceae) induce microRNA-146a and have anti-inflammatory and chemopreventive effects in intestinal myofribroblast CCD-18Co cells

Polyphenolics extracted from yaupon holly (Ilex vomitoria, Aquifoliaceae) (YH) leaves were investigated in human colon cells for their chemopreventive and anti-inflammatory activities. An activity-guided fractionation allowed the selection of YH flavonol-rich fraction due to its preferential inhibition of HT-29 colon cancer viability over the normal CCD-18Co colon cells. Quercetin and kaempferol 3-rutinosides, main components identified in this fraction, protected CCD-18Co cells against reactive oxidative species (ROS) in part due to increased activity of antioxidant enzymes. In addition, up-regulation of microRNA-146a (miR-146a) known as a negative regulator of pro-inflammatory NF-κB activation was the underlying molecular mechanism that protected CCD-18Co from inflammation.
Comparison of viscous and gravity dominated gas–oil relative permeabilities

Abstract Unsteady and steady-state gasflood, centrifuge and gravity-drainage experiments are routinely carried out to determine relative permeabilities for cores taken from petroleum reservoirs. These laboratory studies are often interpreted by simple methods, e.g., JBN or Hagoort method, and give different oil relative permeability for the same core. The objective of this paper is to investigate the factors that affect these tests and determine the best use of the data in the field scale studies. In this study, it has been shown that neglecting capillary pressure can lead to significant errors in the relative permeability curves for both gasflood and centrifuge experiments. The residual oil saturation obtained from a centrifuge experiment is very low (∼1%) for a set of unconsolidated and friable cores from offshore, West Africa with spreading oil and shown to be insensitive to the permeability of the porous medium (in the range studied). A comparison between the relative permeabilities determined from centrifuge and gasflood experiments shows that the residual oil saturation is much higher and oil relative permeability is lower for gasflood tests. An empirical model has been proposed to estimate residual oil saturation as a function of a heterogeneity index and displacement rate for cores obtained perpendicular to the bedding plane. The normalized relative permeabilities obtained from the centrifuge and the gasflood experiment are essentially the same for these vertical cores. The normalized oil relative permeabilities for the two techniques are different for cores obtained parallel to the bedding plane, perhaps due to the effects of layering. The centrifuge relative permeability should be applicable to those parts of the reservoir where the flow is gravity dominated. The gasflood relative permeability can be applicable to viscous dominated regions of the reservoir as long as heterogeneities and flow rates are accounted for properly.
IMPACT OF LOW LEFT VENTRICULAR EJECTION FRACTION ON MORTALITY AFTER VENTRICULAR TACHYCARDIA ABLATION: A MULTICENTER EXPERIENCE

There is limited data on the impact of very low left ventricular ejection fraction (LVEF) on mortality after catheter ablation of ventricular tachycardia (VT). Multicenter, retrospective analysis of all consecutive patients undergoing VT ablation at 4 high volume centers between 2007 and 2010. We
Comparison of methods for the removal of organic carbon and extraction of chromium, iron and manganese from an estuarine sediment standard and sediment from the Calcasieu River estuary, Louisiana, U.S.A.

U.S. National Bureau of Standards (NBS) estuarine sediment 1646 from the Chesapeake Bay, Maryland, and surface sediment collected at two sites in the Calcasieu River estuary, Louisiana, were used to evaluate the dilute hydrochloric acid extraction of Cr, Fe and Mn from air-dried and freeze-dried samples that had been treated by one of three methods to remove organic carbon. The three methods for the oxidation and removal of organic carbon were: (1) 30% hydrogen peroxide; (2) 30% hydrogen peroxide plus 0.25 mM pyrophosphate; and (3) plasma oxidation (low-temperature ashing). There was no statistically significant difference at the 95% confidence level between air- and freeze-dried samples with respect to the percent of organic carbon removed by the three methods. Generally, there was no statistically significant difference at the 95% confidence level between air- and freeze-dried samples with respect to the concentration of Cr, Fe and Mn that was extracted, regardless of the extraction technique that was used. Hydrogen peroxide plus pyrophosphate removed the most organic carbon from sediment collected at the site in the Calcasieu River that was upstream from industrial outfalls. Plasma oxidation removed the most organic carbon from the sediment collected at a site in the Calcasieu River close to industrial outfalls and from the NBS estuarine sediment sample. Plasma oxidation merits further study as a treatment for removal of organic carbon. Operational parameters can be chosen to limit the plasma oxidation of pyrite which, unlike other Fe species, will not be dissolved by dilute hydrochloric acid. Preservation of pyrite allows the positive identification of Fe present as pyrite in sediments.
Adolescents' Views Regarding Uses of Social Networking Websites and Text Messaging for Adolescent Sexual Health Education

Abstract Background: Adolescents frequently report barriers to obtaining sexual health education. Purpose: The purpose of this study was to determine adolescents' views regarding how new technologies could be used for sexual health education. Methods: Focus group interviews were conducted with a purposeful sample of adolescents between 14 and 19 years old. Facilitators asked participants for their views regarding use of social networking web sites (SNSs) and text messaging for sexual health education. Tape-recorded data were transcribed; transcripts were manually evaluated then discussed to determine thematic consensus. Results: Twenty-nine adolescents (65.5% female) participated in five focus groups. Three themes emerged from our data. First, adolescents preferred sexual health education resources that are accessible. Second, adolescents preferred online resources that are trustworthy. Third, adolescents discussed preference for “safe” resources. Discussion: Adolescents were enthusiastic and insightful r...
The effect of epinephrine versus methoxamine on regional myocardial blood flow and defibrillation rates following a prolonged cardiorespiratory arrest in a swine model

Abstract Recent studies in swine have shown that larger doses of epinephrine than those currently employed for cardiopulmonary resuscitation (CPR) significantly improve regional myocardial blood flow following prolonged cardiac arrest. The dose-response effect of a pure alpha-adrenergic agonist, methoxamine, on regional myocardial blood flow has not been investigated in this setting. This study compared the effect of high-dose epinephrine with graded doses of methoxamine on regional myocardial blood flow, oxygen delivery/utilization, and defibrillation rates during CPR. Twenty swine were instrumented for regional myocardial blood flow measurements using radiolabeled tracer microspheres. Measurements of regional myocardial blood flow, oxygen delivery, and oxygen consumption were made during normal sinus rhythm. Ventricular fibrillation was then induced. Following 10 minutes of ventricular fibrillation, CPR was initiated with a pneumatic compressor. Regional myocardial blood flow, oxygen delivery, and oxygen consumption were then measured during CPR. Following 3 minutes of CPR, the swine were allocated to one of four treatment groups (five per group): group I, epinephrine 0.2 mg/kg; group II, methoxamine 0.1 mg/kg; group III, methoxamine 1.0 mg/kg; and group IV, methoxamine 10.0 mg/kg. One minute after drug administration, regional myocardial blood flow, oxygen delivery, and oxygen consumption measurements again were made. Three and one half minutes after drug administration, defibrillation was attempted. Regional myocardial blood flow following drug administration was compared using an analysis of covariance. Epinephrine (0.2 mg/kg) significantly improved myocardial blood flow ( P
Outcomes of Nonoperatively Treated Displaced Scapular Body Fractures

Background Displaced scapular body fractures most commonly are treated conservatively. However there is conflicting evidence in the literature regarding the outcomes owing to retrospective design of studies, different classification systems, and diverse outcome tools.
Probability binning and testing agreement between multivariate immunofluorescence histograms: Extending the chi-squared test

Background A key problem in immunohistochemistry is assessing when two sample histograms are significantly different. One test that is commonly used for this purpose in the univariate case is the chi-squared test. Comparing multivariate distributions is qualitatively harder, as the “curse of dimensionality” means that the number of bins can grow exponentially. For the chi-squared test to be useful, data-dependent binning methods must be employed. An example of how this can be done is provided by the “probability binning” method of Roederer et al. (1, 2, 3). Methods We derive the theoretical distribution of the probability binning statistic, giving it a more rigorous foundation. We show that the null distribution is a scaled chi-square, and show how it can be related to the standard chi-squared statistic. Results A small simulation shows how the theoretical results can be used to (a) modify the probability binning statistic to make it more sensitive and (b) suggest variant statistics which, while still exploiting the data-dependent strengths of the probability binning procedure, may be easier to work with. Conclusions The probability binning procedure effectively uses adaptive binning to locate structure in high-dimensional data. The derivation of a theoretical basis provides a more detailed interpretation of its behavior and renders the probability binning method more flexible.
Method for studying the development, structure and microflora of denture plaque

Pieces of sandblasted, self-adhesive tape were stuck to the fitting surface of maxillary dentures in 17 edentulous subjects with clinically normal palatal mucosa. After 1 week, during which the subjects abstained from denture hygiene, the tape samples were removed for cultural and microscopical examinations. The microorganisms were suspended in RTF by ultrasonic treatment and total viable anaerobic counts and viable counts of yeasts per cm2 of tape were calculated after inoculation of serial dilutions on nonselective medium and sabouraud agar. Total anaerobic viable counts ranged from 4 X 10(4) to 5 X 10(8). By repeated sampling the largest intra-individual variation was 10-fold, only. Yeast counts constituted less than 1% of the total viable counts in all but two of the subjects. Light and electron microscopy showed a bacterial plaque of predominantly cocci and rods.
The event calculus and consistency maintenance

The relationship between nonmonotonic formalisms and the problem of temporal projection has long been recognized, though not well understood. The straightforward application of various nonmonotonic formalisms (circumscription, default logic, etc.) has been blocked by the multiple-extension problem [Hanks and McDermott 87], where a seemingly intuitive set of axioms gives rise to extensions (or minimal models, depending on the formalism) other than the one desired. However, recent work in the semantics of logic programs has gone a long way toward clarifying this situation. In particular, a class of logic programs (called the stratified logic programs) has been identified in which nonmonotonic reasoning can be carried out in a well-defined fashion [Przymusinski 88].This paper presents a system, based on the Event Calculus [Kowalski and Sergot 86], for temporal reasoning in a deductive database context. The axioms used to perform temporal projection are constructed to satisfy the stratification property, so that nonmonotonic inference can be performed safely. The system employs a caching mechanism which stores conclusions drawn from the axioms along with justifications. The cache is managed using truth maintenance techniques which faithfully reflect the nonmonotonic semantics of the system.
Empirical Learning as a Function of Concept Character

Concept learning depends on data character. To discover how, some researchers have used theoretical analysis to relate the behavior of idealized learning algorithms to classes of concepts. Others have developed pragmatic measures that relate the behavior of empirical systems such as ID3 and PLS1 to the kinds of concepts encountered in practice. But before learning behavior can be predicted, concepts and data must be characterized. Data characteristics include their number, error, “size,” and so forth. Although potential characteristics are numerous, they are constrained by the way one views concepts. Viewing concepts as functions over instance space leads to geometric characteristics such as concept size (the proportion of positive instances) and concentration (not too many “peaks”). Experiments show that some of these characteristics drastically affect the accuracy of concept learning. Sometimes data characteristics interact in non-intuitive wayss for example, noisy data may degrade accuracy differently depending on the size of the concept. Compared with effects of some data characteristics, the choice of learning algorithm appears less important: performance accuracy is degraded only slightly when the splitting criterion is replaced with random selection. Analyzing such observations suggests directions for concept learning research.
The Hierarchical Complexity View of Evolution and History

Evolution means different things at different stages of development. Higher stage explanations for it are downward assimilated at lower stages. Different scientific explanations for evolution also reflect different stages of development. Hierarchical complexity of tasks in evolution is a behavioral analytic explanation. It is selection processes of various kinds in tandem with changes in selection tasks' orders of hierarchical complexity. There is neither teleology nor evolutionary favoring of the highest stages of performance. Selection tasks at higher orders of complexity increasingly decenter at all scales of behaviors from thought to history's social periods. These processes account for sociopolitical conflicts over evolution.
Phenocryst-poor rhyolites of bimodal, tholeiitic provinces: the Rattlesnake Tuff and implications for mush extraction models

We consider the origin of rhyolites associated with tholeiitic basalt in bimodal provinces, as exemplified by the Rattlesnake Tuff of the High Lava Plains of eastern Oregon, in comparison to rhyolites associated with calcalkaline suites in light of recent models of extraction of rhyolite from crystal mush (Hildreth, J Volcanol Geotherm Res, 136:169–198, 2004; Bachmann and Bergantz, J Petrol, 45:1565–1582, 2004). The High Lava Plains encompass a strongly bimodal, tholeiite-rhyolite suite, spatially and compositionally related to the Snake River Plain and Yellowstone Plateau. In our assessment we draw the distinction between fractionation dominated processes to make rhyolites from rhyolites and processes required to make the parental rhyolite melt. New isotopic data and compositional zoning profiles in phenocrysts confirm that crystal fractionation dominated the generation of progressively more evolved, discrete rhyolites in the zoned Rattlesnake Tuff and are consistent with an origin of the least evolved high-silica rhyolites by partial melting of a mafic crust. While the most evolved rhyolites are compositionally virtually indistinguishable from those of calcalkaline suites, the parental rhyolites from bimodal suites are more Fe-rich than their calcalkaline counterparts. Oxygen isotope thermometry yields pre-eruptive temperatures of 860°C, in keeping with 800–880°C zircon saturation temperatures. High magmatic temperatures are common among rhyolites of bimodal suites, distinguishing them from cooler rhyolites of calcalkaline suites. Extraction of interstitial melt from a granodioritic mush cannot produce compositions of the Rattlesnake Tuff on the basis of major and trace element arguments (especially Fe, Ba, Sr, and Eu) and on the basis of temperature considerations. Chemically viable parental crystal mushes are syenite and alkali (A-type) granites for the production of all more evolved Rattlesnake Tuff rhyolites; ferro-dacitic mush is required for production of the least-evolved, parental Rattlesnake Tuff rhyolite. Paucity of such ferro-dacitic compositions in tholeiitic bimodal suites, especially compared to the abundance of dacitic (granodioritic) compositions in calcalkaline suites, argues against the mush extraction model for the parental rhyolite. Furthermore, rhyolites of bimodal suites lack associated voluminous eruptions of crystal-rich ignimbrite that might represent a parental mush, as exemplified by the “monotonous intermediate” Fish Canyon Tuff in calcalkaline suites. We conclude that extensive fractionation is common among rhyolites and may obscure their ancestry. Fe-rich parental rhyolites common in bimodal tholeiitic suites, as represented by Rattlesnake Tuff, may often be the result of partial melting of mafic to intermediate crust, in contrast to calcalkaline high-silica rhyolites that are related to voluminous suites of intermediate intrusive rocks where the pre-plutonic mush-extraction model works better.
PHYLOGENETIC POSITION OF BOLBOCOLEON PILIFERUM (ULVOPHYCEAE, CHLOROPHYTA): EVIDENCE FROM REPRODUCTION, ZOOSPORE AND GAMETE ULTRASTRUCTURE, AND SMALL SUBUNIT RRNA GENE SEQUENCES1

Aspects of the reproduction of Bolbocoleon piliferum N. Pringsheim, a common, small, filamentous, endophytic marine green alga, were examined by LM and TEM. These observations were combined with phylogenetic analysis of nuclear-encoded small subunit rRNA gene sequences to assess the phylogenetic position of B. piliferum. Quadriflagellate zoospores and planozygotes derived from fusion of isogametes yielded plants with identical morphology. Zoosporangia and gametangia divided by sequential cleavages. Plugs at the apices of zoosporangia and gametangia formed during development; tubes were found at zoosporangial and gametangial apices after swarmer release. Flagellar apparatuses of zoospores and gametes were similar to those of algae in the Ulvales (Ulvophyceae), except that terminal caps were entire rather than bilobed and rhizoplasts and "stacked" microtubular root configurations were absent. Structures associated with planozygotes were identical to those observed in other algae currently assigned to Ulotrichales and Ulvales. Molecular phylogenetic analyses placed B. piliferum within the Ulvophyceae, at the base of a clade that contains representatives of the families Ulvaceae, Ulvellaceae, and Kornmanniaceae. The results support an earlier hypothesis that B. piliferum constitutes a distinct lineage. Analyses including Kornmanniaceae recover mono'!' phyletic Ulotrichales and Ulvales, whereas analyses omitting the Kornmanniaceae indicate that Ulotrichales is paraphyletic. The structures associated with gamete fusion are conserved within Ulotrichales and Ulvales and perhaps more widely within Chlorophyta.
Modding to the big leagues: Exploring the space between modders and the game industry

Modding is an important characteristic of participatory culture in video games. Studies have shown that PC game modders mod for a host of reasons not least of which as a means of developing the skills and portfolio needed to get a job in the video game industry. Modding culture can be thought of as a point of articulation between the industry and participatory cultural practices. Modding culture is not only concerned with accessing the game industry however, but also puts a high premium on modding for fun or out of love for a particular community or game. Because it effectively straddles market and non-market interests it is important to study how modders negotiate the two sides of modding, which has been at the leading edge of the participatory turn in media consumption and production. This article undertakes an evaluation of modding discourses, first through an evaluation of surveys taken by moderators of modding discussion forums and secondly through an evaluation of discussions regarding technologies used by modders. The article sheds light on the complex ways in which modders' understand the practice of modding. It is framed broadly within political economic theories that have attempted to map modding in post-industrial logics and within theories that have understood it as a participatory culture. Ultimately this paper discusses other participatory practices, drawing parallels with modding and venturing some observations about user participation in the new media environment.
Fluorescence-lifetime measurements in atmospheric-pressure flames using nanosecond-pulsed lasers

Measurements of fluorescence lifetimes are needed to quantify concentration measurements when using linear laser-induced fluorescence. However, lifetimes are only a few nanoseconds for many important species at atmospheric pressure. When using a typical Q-switched laser with a pulse width of about 10 ns, the fluorescence follows the shape of the laser pulse and the lifetime cannot be easily measured. In this paper, a technique is described for experimentally determining the fluorescence lifetime in atmospheric-pressure flames using a nanosecond-pulsed laser; that is, measurement of a lifetime an order-of-magnitude faster than the laser pulse itself. This technique relies on an observable temporal shift in the fluorescence signal as a function of the lifetime. Simulations show the efficacy of this approach, and data in liquid samples and in an atmospheric-pressure flame show excellent agreement with prior picosecond measurements. This technique is successful because only the temporal shift is examined and details of the fluorescence profile are ignored.
Periodic retinoic acid-STRA8 signaling intersects with periodic germ-cell competencies to regulate spermatogenesis.

Mammalian spermatogenesis—the transformation of stem cells into millions of haploid spermatozoa—is elaborately organized in time and space. We explored the underlying regulatory mechanisms by genetically and chemically perturbing spermatogenesis in vivo, focusing on spermatogonial differentiation, which begins a series of amplifying divisions, and meiotic initiation, which ends these divisions. We first found that, in mice lacking the retinoic acid (RA) target gene Stimulated by retinoic acid gene 8 (Stra8), undifferentiated spermatogonia accumulated in unusually high numbers as early as 10 d after birth, whereas differentiating spermatogonia were depleted. We thus conclude that Stra8, previously shown to be required for meiotic initiation, also promotes (but is not strictly required for) spermatogonial differentiation. Second, we found that injection of RA into wild-type adult males induced, independently, precocious spermatogonial differentiation and precocious meiotic initiation; thus, RA acts instructively on germ cells at both transitions. Third, the competencies of germ cells to undergo spermatogonial differentiation or meiotic initiation in response to RA were found to be distinct, periodic, and limited to particular seminiferous stages. Competencies for both transitions begin while RA levels are low, so that the germ cells respond as soon as RA levels rise. Together with other findings, our results demonstrate that periodic RA–STRA8 signaling intersects with periodic germ-cell competencies to regulate two distinct, cell-type-specific responses: spermatogonial differentiation and meiotic initiation. This simple mechanism, with one signal both starting and ending the amplifying divisions, contributes to the prodigious output of spermatozoa and to the elaborate organization of spermatogenesis.
Fabrication of high-efficiency multilayer-coated gratings for the EUV regime using e-beam patterned substrates

The use of multilayer reflection coatings has proven to be an effective means for improving the efficiency of soft X-ray and extreme ultraviolet gratings. These techniques have recently been extended to e-beam-patterned binary blazed substrates. Here we present further refinement of the e-beam-patterned substrate method, demonstrating near normal-incidence reflection efficiencies as high as 41% into the first-diffracted order.
A Flashback-Resistant Burner for Use with the Nitrous Oxide-Acetylene Flame

Abstract The use of the high-temperature nitrous oxide-acetylene flame both in atomic absorption and emission spectroscopy can be hazardous. In particular, the high burning velocity of this gas mixture can cause serious flashback when supported on the conventional slot-type burner. For safe operation of the N2O-C2H2 flame on a slot burner, it is necessary to maintain a high total gas issuing velocity. Commonly, burner start-up procedures require initially lighting a less flashbackprone mixture—and then switching over to nitrous oxide. Often differential flow controllers are employed so that the change over can be accomplished smoothly. However, in conventional burners, if the proper flow rates are not maintained during this change over and during subsequent operation, a rather violent flashback can occur.
HIV-induced syncytia of a T cell line form single giant pseudopods and are motile

The human immunodeficiency virus, HIV, induces syncytium formation in cultures of many T cell lines. These syncytia have previously been viewed as disorganized fusion products in the throes of death. Evidence is presented that in HIV1-infected SupT1 cultures, syncytia five times to over one hundred times larger than single cells organize their many nuclei into blastula-like balls, reorganize their cytoskeleton to mimic that of a single cell, and extend single, giant pseudopods in a polar fashion. Medium-sized syncytia are capable of translocation through extension of these giant pseudopods. The rate of translocation of syncytia is comparable to that of single cells. Single cell motility, syncytium motility and pseudopod extension also appear to play roles in the recruitment of cells into syncytia. Finally, condensation of F-actin at cell-syncytium and syncytium-syncytium adhesion sites suggests the involvement of the cytoskeleton in the adhesion and/or subsequent fusion event. These results suggest that the fusion events involved in HIV-induced syncytia formation involve both cell motility and reorganization of the cytoskeleton, and demonstrate that syncytia are highly organized, motile entities.
International Cooperation in Border Regions: An Overview and Research Agenda:

This paper examines critically various theoretical and conceptual approaches to the analysis of interactions between neighboring border regions. As an important indicator of the degree of rapprochement between nations, the nature and significance of evolving transboundary cooperation in Western Europe and along the U.S.-Mexico border are considered. Despite barriers raised by national governments, such cooperation has been extensive at the regional and local levels. Suggestions are made for research that would contribute to a better under-standing of the processes that foster transboundary cooperation.
Performance Analysis and Evaluation of Assemble-to-Order Systems with Stochastic Sequential Lead Times

We consider the multiproduct and multicomponent assemble-to-order (ATO) systems where the replenishment lead times of the components are stochastic, sequential, and independent of the system state. The component inventories are either controlled by the continuous-time base-stock policies, namely, a base-stock ATO system, or by the continuous-time batch-ordering policies, namely, a batch-ordering ATO system. This paper develops the following results: First, for a base-stock ATO system with a single end product and renewal demand arrivals, we characterize the probability distribution of the delivery lead time, i.e., the time it takes to satisfy a demand. The exact analysis allows us to provide simple proofs for the important system properties. Second, for a base-stock ATO system with multiple end products and demand following independent Poisson processes, we characterize the dependence among the stockout delays of the components. We show that a multiproduct ATO system can be decomposed into multiple single...
Creep Recovery and Hardening Effects on the Stress Field Near a Crack Tip Under Variable Loads

It is thought that creep recovery may be one of the main causes of acceleration of crack growth rates under creep fatigue interaction conditions. In this paper, effects of creep recovery and hardening on the near tip fields under variable loads are examined. Robinson’s constitutive relation, which is based on the Bailey-Orowan model, is used to take these effects into account. It is found that the Hutchinson-Rice-Rosengren type singular fields prevail near the crack tip for any combination of material parameters. The variation in intensities of the singular fields is discussed.
Visually Relating Gene Expression and in vivo DNA Binding Data

Gene expression and in vivo DNA binding data provide important information for understanding gene regulatory networks: in vivo DNA binding data indicate genomic regions where transcription factors are bound, and expression data show the output resulting from this binding. Thus, there must be functional relationships between these two types of data. While visualization and data analysis tools exist for each data type alone, there is a lack of tools that can easily explore the relationship between them. We propose an approach that uses the average expression driven by multiple of cis-control regions to visually relate gene expression and in vivo DNA binding data. We demonstrate the utility of this tool with examples from the network controlling early Drosophila development. The results obtained support the idea that the level of occupancy of a transcription factor on DNA strongly determines the degree to which the factor regulates a target gene, and in some cases also controls whether the regulation is positive or negative.
New frontiers for commercial applications of terahertz

We present several preliminary experimental data to demonstrate the potential of terahertz imaging for various commercial applications. Specifically, terahertz images and signatures are presented using terahertz pulsed imaging (TPI™) for green leaves, lung cancer tissues, as well as farm and wild raised salmons. Raw data from these measurements provided the associated refractive indices and absorption coefficients. Time domain reflectometry (TDR) signatures were also collected at terahertz frequencies for integrated circuits. This was done using an electro-optic terahertz pulse reflectometry (EOTPR) system. In all cases, it is demonstrated that discriminatory information can be readily obtained from terahertz images or TDR signals for various organic and non-organic materials.
Influence of Rhodamine WT Properties on Sorption and Transport in Subsurface Media

Laboratory batch and column studies with two subsurface media demonstrated that structural isomers of rhodamine WT (RWT) are responsible for the observed two-step sigmoidal breakthrough curve. A linear isotherm was observed at RWT concentrations 100 μ/1. In column studies, the breakthrough curve for RWT was observed to exhibit a plateau at values of C/ Co around 0.43 to 0.49. Titration curves for RWT indicated a single pKa value of 5.1. The pH effects on the breakthrough curve for RWT were evaluated and showed no evidences related to the observed two-step breakthrough curve. Sorption of RWT was observed to be much more significant at low values of pH (e.g., 3.0), and to decrease at elevated values of pH (e.g., 11.3); both observations are consistent with the ionogenic nature of RWT and the surface charge of the media. Chromatographic separation of RWT resulted in two UV spectrophotoscopically distinct peaks indicating two structural isomers. Combination of the individual breakthrough curves for each of the two RWT isomers resulted in a two-step breakthrough curve similar to that observed for the original RWT solution. The distinct sorptive characteristic of the different isomers is explained by the relative positions of two carboxyl groups (COO-) attached to the phenyl ring of RWT.
The Single‐Pedicle Retroauricular Advancement Flap

. The single-pedicle retroauricular advancement flap is very useful for defects of the posterior ear surface and along the helical rim. Design elements are simple, vascular support excellent, and the aesthetic reconstruction of involved areas highly acceptable. Several cases are demonstrated photographically along with appropriate commentary.
Social Workers in Private Practice: A Descriptive Study of What they do

This article reports on the findings of a national study conducted with a randomized sample of NASW members in private practice. The study examined such issues as populations served, lengths of treatment, fees charged, treatment approaches, and whether private practitioners used evidence-based practice or practice-based evidence in their work with clients. The article reflects on such questions as whether private practitioners have abandoned the social work mission, whether graduate schools should aim to prepare social workers for private practice, and whether social workers in private practice adhere to the NASW Code of Ethics.
Artificial intelligence in medical consultation systems: a review

A history of artificial intelligence (AI) in medicine is presented. Pre-1970 medical consultation systems are described briefly. Early prototypes of AI consultation systems are then examined. The shift from predominantly general-problem solving research to domain-specific knowledge-based systems research is discussed. Two phases in the evolution of ideas during the period from 1975-82 are distinguished. From 1975 to 1978, prototype systems were fully developed and subjected to critical testing, while giving rise to generalizations. During the period from 1978 to 1982, the first general system-building frameworks were produced. The reexamination of the foundations of medical consultation systems and the shift to rule-based systems during the period 1982 to 1987 are discussed. >
Pilot study of iPS-derived neural cells to examine biologic effects of alcohol on human neurons in vitro.

Background Studies of the effects of alcohol on NMDA receptor function and gene expression have depended on rodent or post-mortem human brain models. Ideally, the effects of alcohol might better be examined in living neural tissue derived from human subjects. In this study, we used new technologies to reprogram human subject-specific tissue into pluripotent cell colonies and generate human neural cultures as a model system to examine the molecular actions of alcohol.
Extrapolation of the Isabelle Design to 400 × 400 GeV

Consideration of a national program for the development of new high energy facilities during the next ten years suggests that the most appropriate energy for proton storage rings may be higher than the 200 × 200 GeV of the present ISABELLE design. It has been indicated that 300 × 300 GeV or 400 × 400 GeV may provide a more reasonable step to maximize the scientific potential of the next major proton storage ring facility. A preliminary analysis of the design consequences of changing the ISABELLE energy to 300 × 300 GeV and 400 × 400 GeV is given, keeping the luminosity, maximum field and most of the original design parameters unchanged. It is concluded that the ISABELLE concept can be extrapolated to 400 × 400 GeV without any unmanageable technical problems and that even higher energies seem to be feasible.
Demonstration of dimer formation of the cytoplasmic domain of a transmembrane osmosensor protein, EnvZ, of Escherichia coli using Ni-histidine tag affinity chromatography

EnvZ is a transmembrane osmosensor which regulates the phosphorylation of OmpR, a transcription factor for ompF and ompC genes which encode the major outer membrane porin proteins, OmpF and OmpC in Escherichia coli. Autophosphorylation of EnvZ occurs through a transphosphorylation reaction between two EnvZ molecules. To elucidate the molecular mechanism of signal transduction by EnvZ, we examined the dimer formation of the EnvZ cytoplasmic domain [EnvZ(C)]. For this purpose, we developed a method to determine the complex formation between the purified EnvZ(C) and the purified His6-EnvZ(C) by means of Ni-6xhistidine tag affinity chromatography. When the mixture of EnvZ(C) and His6-EnvZ(C) was applied to Ni-NTA resin, both His6-EnvZ(C) and EnvZ(C) were bound to the resin, indicating that EnvZ can form an oligomer without the periplasmic and transmembrane domains. Binding experiments using the Ni-NTA resin revealed that EnvZ(C) forms a dimer with the Ka value for dimerization being approximately 10(5) M(-1) in the equilibrium state.
Effect of sex on counterregulatory responses to exercise after antecedent hypoglycemia in type 1 diabetes

A marked sexual dimorphism exists in healthy individuals in the pattern of blunted neuroendocrine and metabolic responses following antecedent stress. It is unknown whether significant sex-related ...
Power Requirements of Swimming: Do New Methods Resolve Old Questions?

A recurring question in the study of fish biomechanics and energetics is the mechanical power required for tail-swimming at the high speeds seen among aquatic vertebrates. The quest for answers has been driven by conceptual advances in fluid dynamics, starting with ideas on the boundary layer and drag initiated by Prandtl, and in measurement techniques starting with force balances focussing on drag and thrust. Drag (=thrust) from measurements on physical models, carcasses, kinematics as inputs to hydromechanical models, and physiological power sources vary from less than that expected for an equivalent rigid reference to over an order of magnitude greater. Estimates of drag and thrust using recent advances largely made possible by increased computing power have not resolved the discrepancy. Sources of drag and thrust are not separable in axial undulatory self propulsion, are open to interpretation and Froude efficiency is zero. Wakes are not easily interpreted, especially for thrust evaluation. We suggest the best measures of swimming performance are velocity and power consumption for which 2D inviscid simulations can give realistic predictions. Steady swimming power is several times that required for towing an equivalent flat plate at the same speed.
Security Models and Requirements for Healthcare Application Clouds

With the widespread use of electronic health record (EHR), building a secure EHR sharing environment has attracted a lot of attention in both healthcare industry and academic community. Cloud computing paradigm is one of the popular healthIT infrastructure for facilitating EHR sharing and EHR integration. In this paper we discuss important concepts related to EHR sharing and integration in healthcare clouds and analyze the arising security and privacy issues in access and management of EHRs. We describe an EHR security reference model for managing security issues in healthcare clouds, which highlights three important core components in securing an EHR cloud. We illustrate the development of the EHR security reference model through a use-case scenario and describe the corresponding security countermeasures and state of art security techniques that can be applied as basic security guards.
Random sampling from hash files

In this paper we discuss simple random sampling from hash files on secondary storage. We consider both iterative and batch sampling algorithms from both static and dynamic hashing methods. The static methods considered are open addressing hash files and hash files with separate overflow chains. The dynamic hashing methods considered are Linear Hash files [Lit80] and Extendible Hash files [FNPS79]. We give the cost of sampling in terms of the cost of successfully searching a hash file and show how to exploit features of the dynamic hashing methods to improve sampling efficiency.
Asynchronous channel hopping for establishing rendezvous in cognitive radio networks

In Cognitive Radio (CR) networks, establishing a link between a pair of communicating nodes requires that their radios are able to “rendezvous” on a common channel (a.k.a. a rendezvous channel). When unlicensed (secondary) users opportunistically share spectrum with licensed (primary or incumbent) users, a given rendezvous channel may become unavailable due to the appearance of licensed user signals, which makes rendezvous impossible. Ideally, any node pair should be able to rendezvous over every available channel to minimize the possibility of such rendezvous failures. Channel hopping (CH) protocols have been proposed previously for establishing pairwise rendezvous. Some of them enable pairwise rendezvous over all channels but require global clock synchronization, which is very difficult to achieve in decentralized networks. In this paper, we present a systematic approach, called asynchronous channel hopping (ACH), for designing CH-based rendezvous protocols for decentralized CR networks. The resulting protocols are resistant to rendezvous failures caused by the appearance of primary user signals and do not require clock synchronization. We propose an optimal ACH design that maximizes the rendezvous probability between any pair of nodes, and show its rendezvous performance via simulation results
Dual-Class Shares and Active Investment Strategies

In this article, the authors propose a strategy that exploits significant deviations from parity between the two classes of shares for dual-class firms. The strategy involves taking a short position in one class and a long position in the other class, depending on whether the deviation is above or below parity. The analysis reveals potentially profitable opportunities for active investors. The authors “alpha test” the strategy on two sample firms (Blockbuster Entertainment and Lennar Homes) with a retail brokerage account to ensure that it is logistically feasible.
MEMS Scanning Diffraction Grating Spectrometer

A new type of grating spectroscopy, using a micromachined scanning grating spectrometer is presented. We achieve resolution of 17-70 nm in the spectroscopy using a HeNe laser as a source
Understanding Psychological Safety in Health Care and Education Organizations: A Comparative Perspective

Psychological safety plays a vital role in helping people overcome barriers to learning and change in interpersonally challenging work environments. This article focuses on two such contexts—health care and education. The authors theorize differences in psychological safety based on work type, hierarchical status, and leadership effectiveness. Consistent with prior research, the authors employ cross-industry comparison to highlight distinctive features of different professions. The goal is to illuminate similarities and differences with implications for future psychological safety research. To do this, the authors review relevant literature and present analyses of large data samples in each industry to stimulate further research on psychological safety in both sectors, separately and together.