cssi/SciSciGPT-SciSciNet huggingface dataset:
Experience with Image Management Networks at Three Universities: Is the Cup Half-Empty or Half-Full?

The digital imaging network (DIN) project is a federally funded demonstration and evaluation project which studies the usefulness of emerging management technologies for radiological images. The primary emphasis of the university-based efforts is in the clinical operation of the entire network. The project is interested in the evaluating the concept rather than any particular product.
Qualitative Spatial Reasoning in Interpreting Text and Narrative

Abstract Simple natural language texts and narratives often raise problems in commonsense spatial knowledge and reasoning of surprising logical complexity and geometric richness. In this article, I consider a dozen short texts—five taken from literature, the remainder contrived as illustrations—and discuss the spatial reasoning involved in understanding them. I conclude by summarizing their common features, and by tentatively drawing some morals for research in this area.
Investigation of deep level defects in electron irradiated indium arsenide quantum dots embedded in a gallium arsenide matrix

Abstract Gallium arsenide diodes with and without indium arsenide quantum dots were electron irradiated to investigate radiation induced defects. Baseline and quantum dot gallium arsenide pn-junction diodes were characterized by capacitance–voltage measurements, and deep level transient spectroscopy. Carrier accumulation was observed in the gallium arsenide quantum dot sample at the designed depth for the quantum dots via capacitance–voltage measurements. Prior to irradiation, a defect 0.84 eV below the conduction band (EC – 0.84 eV) was observed in the baseline sample which is consistent with the native EL2 defect seen in gallium arsenide. After 1 MeV electron irradiation three new defects were observed in the baseline sample, labeled as E3 (EC – 0.25 eV), E4 (EC – 0.55 eV), and E5 (EC – 0.76 eV), consistent with literature reports of electron irradiated gallium arsenide. Prior to irradiation, the addition of quantum dots appeared to have introduced defect levels at EC – 0.21, EC – 0.38, and EC – 0.75 eV denoted as QD–DX1, QD–DX2, and QD–EL2 respectively. In the quantum dot sample after 1 MeV electron irradiation, QD–E3 (EC – 0.28 eV), QD–E4 (EC – 0.49 eV), and QD–EL2 (EC – 0.72 eV) defects, similar to the baseline sample, were observed, although the trap density was dissimilar to that of the baseline sample. The quantum dot sample showed a higher density of the QD–E4 defect and a lower density of QD–E3, while the QD–EL2 defect seemed to be unaffected by electron irradiation. These findings suggest that the quantum dot sample may be more radiation tolerant to the E3 defect as compared to the baseline sample.
Expression of Epi 1, an epidermis-specific marker in Xenopus laevis embryos, is specified prior to gastrulation

The induction of morphologically observable neural structures occurs as the result of tissue interactions between chordamesoderm and overlying ectoderm beginning at gastrulation. Since the future dorsal, and hence neural, side of the embryo is determined around the time of fertilization, we questioned whether the presumptive neural epithelium might have received some developmental instructions prior to contact with the migrating chordamesoderm. Epi 1, a cell surface antigen present only on epidermal epithelium was used as a marker to determine when epithelial cells have been programmed to express (or not express) this epidermal-specific molecule. We find that ligated animal halves of precleavage embryos already contain all the information necessary for expression of Epi 1 at the appropriate developmental time (early neurula). By at least the eight-celled stage, the epithelial cells derived from ventral animal blastomeres are much better at expressing the Epi 1 antigen than their dorsal counterparts. We suggest that the mechanisms responsible for expression of the Epi 1 antigen are localized within the animal hemisphere prior to the onset of cleavage. By the third cleavage division, dorsal animal cells appear to have received information which inhibits the subsequent expression of this epidermal antigen.
Social anxiety, public self-consciousness, and variability of behavior.

A number of researchers have suggested that individuals vary in how they present themselves across time and situations ( 4 ) and that social anxiety and public selfconsciousness are possible predictors of such variability (1, 2 ) . Lennox ( 2 ) obtained only a moderate correlation between social anxiety and cross-situational variability and no correlation between public self-consciousness and variability of behavior, however, social anxiety and public self-awareness were moderately correlated. The present study is a replication of the Lennox ( 2 ) study. Altogether 40 men and 4 6 women were drawn voluntarily from a two-year nursing program and from an introductory psychology class of a junior college in Southern California. Subjects completed the Self-consciousness Scale ( 1 ) which measures public self-consciousness and social anxiety and the Lennox-Wolfe Cross-sirnational Variability of Behavior Scale ( 3 ) as one 56-item self-report survey. The response format was a six-point Likert scale ranging from "Certainly, always false" to "Certainly, always true." Men and women did not score differently o n the scales and the total means and standard deviations for public self-consciousness, social anxiety, and cross-situational variability scores were 20.7 and 5.5, 16.2 and 3.7, and 18.3 and 4.6, respectively, which are nor different from the ones Lennox ( 2 ) obtained. Unlike Lennox, no correlation was obtained berween social anxiety and public self-consciousness ( T = .14). However, consistent with Lennox, the cross-situational variable was not correlated with public self-awareness ( r = .15) but correlated significantly with social anxiety ( r = .32, p < .01). These results replicate the findings by Lennox ( 2 ) and support the contention that variability of behavior across situations may occur with a motive to avoid disapproval or negative evaluation. The issue of the relative contributions of dispositional and situational variables to the variability of behavior requires more substantial groups and analysis of tests.
Asymptotic optimality of constant capacity allocation policies for dynamic resource planning

We consider a stochastic capacity problem of dynamically matching the supply of resources and the uncertain demand for resources over a planning horizon of T periods. If demand exceeds the resource capacity in any time period, then such excess demand is lost and a penalty is incurred for the amount of lost demand. The discrete-time model reflects the relative time granularity at which resource capacity decisions can be made, whereas a lead time L > 0 represents in the model the relative time-scale difference between when a resource capacity decision is made and when this capacity decision takes effect. Our optimal control problem then is to determine the best policy for making resource capacity allocation decisions in each period, based on the demand realized up to that period, with the goal of maximizing netbenefit in expectation over the planning horizon. The net-benefit structure of each period in our model consists of a per-unit penalty for insufficient resource capacity to serve uncertain demand and a per-unit cost for the amount of resource capacity allocated. Such resource capacity problems arise within many different computing/networking applications, including capacity provisioning for cloud computing environments where high-frequency demand, having considerable uncertainty, needs to be served by resource capacity allocations over planning horizons during which any decisions to change the resource capacity allocation requires relatively long lead times. This resource capacity allocation model can be mapped in a mathematically equivalent manner to lost-sales inventory models [6]. In particular, the optimal order policy of the corresponding stochastic inventory control problem can be directly mapped to the optimal resource capacity policy, where the capacity allocation for any period is equivalent to the (nonnegative) inventory at the end of the period. We therefore consider henceforth our stochastic capacity planning problem within the context of stochastic lost-sales inventory control problems. Lost-sales inventory models have a long and rich history in the research literature, starting with their introduction by Bellman et al. [1]. Certain properties of the optimal policy have been investigated by various researchers; see, e.g., [8]. With respect to computation of the optimal policy, the primary approach has been dynamic programming, combined with various heuristics to speed up computations [7]. However, since the state-space of any such dynamic program
Argon and nitrogen adsorption studies of changes in connectivity of ordered cage-like large mesopores during the hydrothermal treatment

Abstract FDU-1 silicas with large cage-like mesopores were synthesized, using tetraethyl orthosilicate as a silica source and a poly(ethylene oxide)–poly(butylene oxide)–poly(ethylene oxide) triblock copolymer (EO 39 BO 47 EO 39 ) as a structure-directing agent. The evolution of the FDU-1 pore structure during a hydrothermal treatment at 373, 393, and 413 K was studied, using nitrogen and argon adsorption at 77 K. As the time of the hydrothermal treatment was extended, a moderate increase in the pore cage diameter and a significant enlargement of the pore entrances took place, as inferred from the analysis of adsorption and desorption branches of isotherms, respectively. The materials retain a monodisperse distribution of pore cage diameters. On the other hand, argon and nitrogen desorption data provided evidences that there are two major populations of pore entrances according to their diameter and that they both undergo a concomitant enlargement as the hydrothermal treatment is prolonged. Argon desorption was superior in providing information about pore connectivity in FDU-1 samples, except for those obtained after particularly severe hydrothermal treatments (long time or high temperature). The latter materials had a fraction of pores, which were so large that the capillary condensation of argon at 77 K in them was not observed, and consequently, the information regarding the connectivity and volume of this fraction of pores cannot be extracted from the argon data. In the case of relatively large mesopores (above ∼15–20 nm), nitrogen that exhibits capillary condensation at 77 K in much wider range of pore sizes (up to 100–200 nm) is better as far as the pore connectivity assessment from desorption data is concerned.
Solvent extraction separations of the lanthanides and selected metal ions with 1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octanedione

Abstract 1,1,1,2,2,3,3-Heptafluoro-7,7-dimethyl-4,6-octanedione (0.1 M) in benzene was used for the solvent extraction separation of the lanthanides and other selected metals from an aqueous phase containing l M total acetate in the pH range 1–7. A series of batch extractions was performed with the various metals and percent extraction versus pH curves were constructed. The lanthanides studied were completely extracted in the pH range of 5.7–7.0. Of the other metals that were investigated, only iron(III) and copper(II) were completely extracted. While the separation factors achieved for adjacent lanthanides were not large, the countercurrent distribution studies showed that such separations are feasible.
A program to reduce the number of open I/T jobs at Purdue University: an industry case study

The number of unfilled information technology (IT) positions in demand in the United States is estimated at 1.6 million this year. The demand for skilled IT people far exceeds the supply and it is estimated that half of the 1.6 million positions will likely remain vacant. Due to the shortage of skilled I/T professionals, companies and universities have to be creative and develop in-house programs that will allow them to produce their own IT professionals from among a pool of employees working in non-technical areas or possessing non-technical degrees. Purdue University has developed such a program that will help fill open computing positions by providing people with a solid educational foundation as well as current technical skills. This paper discusses the program Purdue has put into place to help overcome its shortage of qualified I/T professionals.
Transitional problems accompanying vocational development and college graduation

Abstract In order to determine whether college graduation and vocational development are accompanied by an upsurge in amount and kinds of personal problems, senior students were contrasted with juniors according to three categories of specific-diffuse postgraduate career endeavors. Personal adjustment problems were assessed by the Mooney Problem Checklist, and response bias controlled by the MMPI K Scale. Results indicated that students report increased personal problems during the senior year, specifically where vocational choices are decisively formulated; furthermore, problems tend to cluster into specifiable adjustment areas. Findings were discussed in terms of college graduation as a transitional stage, and implications were drawn for the career counseling process.
Solubility-based gas separation with oligomer-modified inorganic membranes

Abstract The potential of hybrid organic–inorganic membranes for separating organic molecules from air, based on a solubility-selective mechanism, was evaluated. Alumina membranes with average pore sizes near 5 and 12 nm were surface-derivatized with various alkyl trichlorosilanes, and their permeances to nitrogen, methane, and propane gases were evaluated at feed pressures up to 2 bar. The permeation rates in the modified membranes generally decreased by two to three orders of magnitude compared with the untreated membranes, while the propane/nitrogen selectivity increased significantly. The membrane performance was correlated with the materials and synthesis conditions employed in the modification, which indicated an ability to control the hydrophobic character and free volume of the hybrids. The maximum propane/nitrogen selectivity observed was 32, which compares very favorably to the best results reported for purely polymeric membranes. This study demonstrates that the synthesis of hybrid membranes with tunable free volume and surface chemistry is feasible, and that such membranes may achieve high performance in solubility-based separations.
Heat Transfer Through Small Moveable Gas Gaps in a Multi-Body System Using the ANSYS Finite Element Software

The Thermal Hydraulics and Irradiation Engineering (THIE) Group at Oak Ridge National Laboratory (ORNL) designs and builds capsules in which to irradiate advanced fuels and materials that are typically inserted into ORNL’s High Flux Isotope Reactor. Experiments are designed to achieve a target temperature that ranges from 250°C to 1200°C. Most capsules do not have active temperature measurement or control, which puts an imperative on accurate temperature simulation. Temperature control in these capsules is accomplished by designing specific gaps between adjacent parts and filling the capsules with an inert gas: helium, neon, or argon.Most any finite element solver will do an excellent job estimating temperatures within individual parts, but the simulation challenge for these complex, multi-body systems is to accurately predict the heat transfer through contact surfaces or interstitial gas gaps. The gas gaps are on the order of 150 μm, so accurate simulation must include thermal expansion of the adjacent parts, the thermal jump effect on the part surfaces, and the possibility the parts will touch or break contact during expansion. This paper will discuss the limitations in thermal contact modeling in finite element modelers and the algorithms the THIE Group uses to overcome these limitations.Copyright © 2013 by ASME
Characterization of SEN3800-associated virulence of Salmonella enterica serovar Enteritidis phage type 8

Salmonella is a major public health concern due to the consumption of contaminated food. Salmonella enterica serovar Enteritidis (SE) infection in humans is often associated with the consumption of contaminated poultry products. Binding of the bacterium to the intestinal mucosa is a major pathogenic mechanism of Salmonella in poultry. In this study, transposon mutagenesis identified SEN3800 as a potential binding mutant of SE. Therefore, we hypothesize that SEN3800 plays a role in the colonization ability of SE in the gastrointestinal tract of poultry. To test our hypothesis, we created a mutant of SE in which SEN3800 was deleted. We then tested the in-vitro and in-vivo binding ability of ∆SEN3800 when compared to the wild-type and complemented SE strains. Our data showed a significant decrease in the binding ability of ∆SEN3800 to T84 intestinal epithelial cells, as well as in the small intestine and cecum of poultry. Furthermore, this binding defect correlated to a defect in invasion, as evidenced by a cell culture model using T84 intestinal epithelial cells and bacterial recovery from the livers and spleens of chickens. Overall, these studies indicate that SEN3800 contributes to the colonization ability of Salmonella in the gastrointestinal tract of poultry.
Mississippian Conodont Zones of Southeastern Arizona: ABSTRACT

Analyses of conodont faunas from Mississippian rocks in southeastern Arizona differentiate 7 conodont zones and 1 zone essentially barren of conodonts. Based on this conodont zonation, the Escabrosa Limestone ranges in age from late Kinderhookian (Siphonodella isosticha-S. cooperi zone) to late Meramecian (Taphrognathus varians-Apatognathus-Cavusgnathus zone). The Paradise Formation, represented by only the Gnathodus girtyi-Cavusgnathus zone, is middle Chesterian in age. Accordingly, the boundaries of both formations are represented by unconformities. The conodont fauna is large and diversified: 387 samples from 7 localities yielded 6,600 specimens representing 118 form species of 30 form genera. Species of Siphonodella, Pseudopolygnathus, Polygnathus, Gnathodus, Cavusgna hus, Apatognathus, and Taphrognathus are especially important in the zonation. The zonation recognized suggests relatively rapid transgression of Mississippian seas across a shelf of low relief in southeastern Arizona. End_of_Article - Last_Page 642------------
Laterality tests: an inferential problem.

Summary A Baysean analysis is used to examine some of the inductive inferences about hemispheric “dominance” based on various laterality measures (e.g., dichotic listening). The results reveal some glaring errors of induction that may occur when inferences are made on constructs that have a low probability of occurrence in the population (i.e., right brain speech). The problem of measurement error and test validity is also discussed.
Ultra-thin epitaxial Al and Cu films on CaF2/Si(1 1 1)

Abstract In this work, smooth epitaxial films of Al and Cu with thickness between 5 and 20 nm have been grown by molecular beam epitaxy (MBE). This was done in order to study the surface contribution to scattering of conduction electrons, without masking effects of grain boundary scattering. Aluminum epitaxy on CaF2/Si(1 1 1) was confirmed by reflection high energy electron diffraction (RHEED). The surface and interface rms roughness below 0.3 nm was achieved for 10 nm-thick Al films, as measured by atomic force microscopy (AFM). Threading screw dislocations but no grain boundaries were observed in these films by scanning tunneling microscopy (STM). Preliminary resistivity measurements on the films between 4 and 20 nm thick agreed qualitatively with the Fuchs–Sondheimer model of resistivity size effect due to diffuse electron scattering from surfaces. For Cu, the epitaxial growth was obtained when depositing on a 3 nm-thick Al seed layer.
Lessons in hypoxic adaptation from high-altitude populations

An increase in hemoglobin level is seen in virtually all lowlanders who move to or train at altitude; however, studies of high-altitude native populations illustrate that this response is not necessary for successful long-term residence. Indigenous populations living at the same altitude have differences not only in hemoglobin level but also in other traits like oxygen saturation. Support for a genetic causation for differences in features of oxygen transport, namely hemoglobin levels and oxygen saturation, is derived from kindred studies among the highlander populations. Indeed, evidence from Tibet suggests that inferred genes for high oxygen saturation are associated with higher offspring survival. It may be that signaling molecules like nitric oxide and transcription factors such as hypoxia-inducible factor could act as an upstream regulator for highlander traits. However, the preponderance of data suggests that it is unlikely that one process or even a common set of processes is responsible for successful biologic adaptation shown in all three resident high-altitude populations. Future studies will require the ability to identify combinations of genetic variants with outcomes including expression levels, appropriate phenotypes, and functional responses.
Effects of temperature and nutritional state on the acute toxicity of acridine to the calanoid copepod, Diaptomus clavipes schacht

Acute toxicity tests were performed on adult males and females of a freshwater calanoid copepod, Diaptomus clavipes Schacht, using the azaarene acridine as the test compound. Tests were performed at three temperatures (16, 21 and 26°C) and over a range of nutritional states (fed, starved and stock). Observations on mortality were made at 24-h intervals for 96 h. Analysis of the data was based on comparisons (using different treatment combinations) of the parameters in a logistic survival function used to describe the mortality data. Median lethal concentrations (using 96-h LC50 values) were estimated from the logistic survival function as well as from the probit function, for comparative purposes. The LC50 values ranged from 1.64 to 6.70 mg/L, depending on temperature, nutritional state of the animals and sex. The LC50 values were highest for animals (fed before testing) at 16°C. As food availability decreased and temperature increased, toxicity of acridine increased up to fourfold. No significant differences in LC50 values were found between the sexes except in starved animals at 26°C, when males were more sensitive than females. This difference in toxicity between the sexes at 26°C may be due to differences in nutritional stress between the sexes (at this temperature), since control mortality at this temperature was also higher in males than in females.
Stimulation by subsynaptosomal fractions of transmitter efflux from plain synaptic vesicle fraction.

The effects were investigated of purified subsynaptic fractions on the efflux of radioactivity from a plain synaptic vesicle fraction which had incorporated [3H]dopamine. About 50% of the radioactivity incorporated into the plain vesicles (120 μg protein) was liberated on exposure to purified synaptic membranes (30 μg protein). The synaptic membrane-dependent efflux appeared to depend on both adenosine triphosphate and divalent cations, especially Ca2+. Of the subcellular fractions used, the heavy microsomal fraction showed the same effects as the synaptic membrane fraction. Purified synaptic junctions exhibited the strongest stimulating effects: the efflux was 2 times greater than that observed with synaptic membranes. The stimulating effects of myelin were less than oneseventh of those of synaptic junctional fraction. These observations may indicate that the transmitters are liberated by interaction of vesicle membrane with synaptic membrane in the presence of ATP and divalent cations.
FINE STRUCTURE OF CELL SURFACE SPECIALIZATIONS IN THE MATURING DUODENAL MUCOSA OF THE CHICK

Cell surfaces in the duodenal mucosa have been studied in maturing tissue of the chick from incubation until hatching. Changes in the distribution of mitoses in this tissue give an indication of its rate of maturation. This rate is paralleled in developmental changes in microvilli and junctional complexes. Concentration of mitotic figures towards the base of villous folds is gradual from day 9 to day 16, then rapid to day 19, after which the mature pattern is acquired. By day 11, microvilli appear in a regular pattern which does not alter through hatching. Their height remains the same to day 16 when it increases gradually to day 19, then very sharply. The angle formed between the microvilli and the cell surface increases gradually to day 16, giving evidence of advancing internal structure. Changes in cell adhesion also occur at day 16. Thereafter, following trypsin treatment cells are held together in patches by the tight junctions of the terminal bar, although the desmosomes are separated. The timing of these morphological changes is compared with that of alkaline phosphatase accumulation in this tissue as reported by Moog (13). Increase in the surface area of the microvilli parallels the increase in the activity of the enzyme.
Geometrical illusions in solid objects under ordinary viewing conditions.

The Muller-Lyer and Ponzo illusions were obtained under free binocular viewing of three-dimensional objects, and the function relating magnitude of illusion to fin angle, characteristic of converging-line versions of the Muller-Lyer pattern, was closely paralleled by volumetric (three-cone), line-free objects (but not with an erect, planar "walk-through" construction and moving observers). Illusions cannot be dismissed as artifacts of static, impoverished viewing, therefore, but must be explained within any general theory of perception. Perspective explanations have difficulties with such three-dimensional manifestations, and seem completely inapplicable to our further finding that approximately the same amount of illusion occurred in objects and patterns with no oblique lines or edges. Confusion or averaging theories, not themselves tested here, remain unthreatened by these data.
Our youngest patients' pain--from disbelief to belief?

Though human pain has existed since the dawn of time, formal medical pain relief in the form of anesthesia and analgesia has been available only since the mid-nineteenth century. Even after these measures became available, they were used very selectively for the first 100 years of their existence. The youngest patients, especially, were denied pain relief, probably because they could not complain about their pain as articulately and as effectively as adult patients could. A desperate need existed for health care professionals to recognize and appreciate the fact that their youngest patients could suffer immensely and to adequately address the issue. This article reviews the evolution of knowledge and attitudes regarding young patients' pain and addresses why and how this process occurred. The evolution of knowledge was traced by reviewing the literature found in MEDLINE, CINAHL, and LEXIS-NEXIS searches and through hand searches of articles that were frequently cited. Physiologic, pharmacologic, ethical, and psychologic aspects of young patients' pain are addressed. A unique phenomenon arose from the data reviewed. The process of belief and changes in practice were encouraged not only by advances in science, but also by consumer demand. Advances in the past decade in the management of young patients' pain were profound, but are still not complete. Understanding the evolution surrounding pain recognition in young patients provides a stepping stone that can facilitate further improvements in the management of pain in young patients.
The production of growth-suppressing volatile substances by stored potato tubers

The sprout-suppressing constituent(s) of the volatiles may be removed by a solution of silver sulphate in 96% H2SO4 or by aqueous solutions of mercuric acetate or chloride. but not by 96% H2SO4 alone, suggesting that they may be olefinic, ethereal and/or sulphur-containing. Ethylene may be produced in very small quantities, insufficient to be an active olefinic constituent.
Maximum likelihood analysis for heteroscedastic one-way random effects ANOVA in interlaboratory studies.

Summary. This article presents results for the maximum likelihood analysis of several groups of measurements made on the same quantity. Following Cochran (1937, Journal of the Royal Statistical Society4(Supple), 102–118; 1954, Biometrics10, 101–129; 1980, in Proceedings of the 25th Conference on the Design of Experiments in Army Research, Development and Testing, 21–33) and others, this problem is formulated as a one-way unbalanced random-effects ANOVA with unequal within-group variances. A reparametrization of the likelihood leads to simplified computations, easier identification and interpretation of multimodality of the likelihood, and (through a non-informative-prior Bayesian approach) approximate confidence regions for the mean and between-group variance.
Beryllium geochemistry in soils: evaluation of 10Be/9Be ratios in authigenic minerals as a basis for age models

Soils contain a diverse and complex set of chemicals and minerals. Being an ‘open system’, both in the chemical and nuclear sense, soils have defied quantitative nuclear dating. However, based on the published studies of the cosmogenic atmospheric 10Be in soils, its relatively long half-life (1.5 Ma), and the fact that 10Be gets quickly incorporated in most soil minerals, this radionuclide appears to be potentially the most useful for soil dating. We therefore studied the natural variations in the specific activities of 10Be with respect to the isotope 9Be in mineral phases in eight profiles of diverse soils from temperate to tropical climatic regimes and evaluated the implications of the data for determining the time of formation of soil minerals, following an earlier suggestion [Lal et al., 1991. Development of cosmogenic nuclear methods for the study of soil erosion and formation rates. Current Sci. 61, 636–639.]. We find that the 10Be/9Be ratios in both bulk soils and in the authigenic mineral phases are confined within a narrower range than in 10Be concentrations. Also, the highest 10Be/9Be ratios in authigenic minerals are observed at the soil-rock interface as predicted by the model. We present model 10Be/9Be ages of the B-horizon and the corresponding soil formation rates for several soil profiles. The present study demonstrates that the 10Be/9Be ratios in the authigenic phases, e.g. clay and Fe-hydroxides, can indeed be used for obtaining useful model ages for soils younger than 10–15 Ma. However, the present work has to be pushed considerably further, to take into account more realistic age models in which, for instance, downward transport 10Be and clays, and in-situ dissolution of clay minerals at depths, altering the 10Be/9Be ratios of the acidic solutions, are included. We show that in the case of younger soils (< 1 Ma) studied here, their 10Be inventories and 10Be/9Be ratios have been significantly disturbed possibly by mixing with transported soils.
Modeling of changes in crosslinking for structural silicone sealants subjected to moisture and sunlight

Abstract Structural sealants function as a weather seal and also act as an adhesive joint between the glass and the support structure for the glazing unit. The effects of the various aging factors which are produced by environmental and climatic changes on the silicone elastomers were studied by measuring changes in crosslink density. As a weather seal, the sealants will be exposed to a wide variety of service conditions which include sunlight, moisture, buffeting forces of the wind, oxidative effects of ozone, live load of the building, etc. The question arises, therefore, as to the potential damage caused by these factors on the performance of these sealants. In this study the effects of some of these factors on the structural silicone sealant were correlated through crosslinking changes. The factors considered in this paper are the effects due to moisture and solar radiation. A typical weathering event consisted of exposing sets of test coupons to moisture having different pH levels. These ranged from ...
Singular perturbations and input-to-state stability

This paper establishes a type of total stability for the input-to-state stability property with respect to singular perturbations. In particular, if the boundary layer system is uniformly globally asymptotically stable and the reduced system is input-to-state stable with respect to disturbances, then these properties continue to hold, up to an arbitrarily small offset, for initial conditions, disturbances, and their derivatives in an arbitrarily large compact set as long as the singular perturbation parameter is sufficiently small.
On the algorithmic implementation of stochastic discrimination

Stochastic discrimination is a general methodology for constructing classifiers appropriate for pattern recognition. It is based on combining arbitrary numbers of very weak components, which are usually generated by some pseudorandom process, and it has the property that the very complex and accurate classifiers produced in this way retain the ability, characteristic of their weak component pieces, to generalize to new data. In fact, it is often observed, in practice, that classifier performance on test sets continues to rise as more weak components are added, even after performance on training sets seems to have reached a maximum. This is predicted by the underlying theory, for even though the formal error rate on the training set may have reached a minimum, more sophisticated measures intrinsic to this method indicate that classifier performance on both training and test sets continues to improve as complexity increases. We begin with a review of the method of stochastic discrimination as applied to pattern recognition. Through a progression of examples keyed to various theoretical issues, we discuss considerations involved with its algorithmic implementation. We then take such an algorithmic implementation and compare its performance, on a large set of standardized pattern recognition problems from the University of California Irvine, and Statlog collections, to many other techniques reported on in the literature, including boosting and bagging. In doing these studies, we compare our results to those reported in the literature by the various authors for the other methods, using the same data and study paradigms used by them. Included in the paper is an outline of the underlying mathematical theory of stochastic discrimination and a remark concerning boosting, which provides a theoretical justification for properties of that method observed in practice, including its ability to generalize.
Experimental modeling of jet-ring turbine disk cooling

The experimental facility and some early results are described from a current research program modeling turbine disk cooling with multiple impinging jets, such as employed on the Space Shuttle Main Engine oxygen turbopump. The study is designed to obtain detailed local convection heat transfer rates on specially constructed turbine disk models that employ either multiple cooling jet impingement near the disk outer radius from a jet ring, or alternatively, single entrance coolant supply into the center of the disk cavity. Jet impingement is an effective scheme for cooling of turbine disks at or near the blade attachment region, but the heat transfer mechanisms and merits relative to other schemes are not well understood. The present study employs two specially constructed full scale plastic model disks, contoured and plane, together with the corresponding stators. Local heat transfer rates are determined by a computer vision system from the response of thin liquid crystal coatings applied to the disk test faces. The present results indicate that multiple jet impingement directed at the blade attachment region results in higher cooling rates in that region than does the same flow supplied to the disk center, but this conclusion must be regarded as tentative.
Direct Luteinizang Activity of FSH-NIH.∗

SummaryThe luteal response to FSH-NIH-S1 and S2 in ovarian isografts in male mice indicates that they have equal LH activity and that this is equivalent to 12% of that of LH-NIH-B1. The response was unchanged by pentobarbital or atropine administration and occurred in androgenized females.
Strong cooperativity between subunits in voltage-gated proton channels

Voltage-activated proton (Hv) channels are essential components in the innate immune response. Hv channels are dimeric proteins with one proton permeation pathway per subunit. It is unknown how Hv channels are activated by voltage and whether there is any cooperation between subunits during voltage activation. Using cysteine accessibility measurements and voltage-clamp fluorometry, we show data consistent with the possibility that the fourth transmembrane segment S4 functions as the voltage sensor in Ciona intestinalis Hv channels. Unexpectedly, in a dimeric Hv channel, the S4 in both subunits must move to activate the two proton permeation pathways. In contrast, if Hv subunits are prevented from dimerizing, the movement of a single S4 is sufficient to activate the proton permeation pathway in a subunit. These results indicate strong cooperativity between subunits in dimeric Hv channels.
How Do African American and Caucasian Women View Themselves at Midlife?1,2

This report examines midlife perceptions of African American and Caucasian women. African American and Caucasian women (aged 42 to 52) completed self-report measures of midlife perceptions, health status, and personality factors. Women had positive perceptions of themselves at midlife; few women reported interpersonal isolation or hopelessness. More optimistic women reported a more positive perception of their current identity and security at midlife. African American women reported more positive perceptions than did Caucasian women. Among those who reported more stressful life events and financial difficulty, African Americans had more positive perceptions, whereas Caucasians had more negative perceptions. Although women tend to view themselves positively at midlife, race is an important moderator of psychosocial factors that may be associated with midlife perceptions.
Nutritional requirements ofCytophaga johnsonae and some of its auxotrophic mutants

A defined medium for growing cells ofCytophaga johnsonae was developed for use in studies of the genetics of gliding motility of this organism. The defined medium, containing only mineral salts and any of six sugars, supports good growth of actively motile cells of several strains ofC. johnsonae. Characteristics of growth in the defined medium and ability of cells to use alternative sources of carbon and nitrogen are reported. Certain compounds, when added to solid media, inhibit colony spread ofC. johnsonae without affecting motility of individual cells. Amino acid requirements were determined for 41 of 43 auxotrophic mutants isolated following penicillin selection of unmutagenized cells growing in the minimal medium.
Microrheological study of polyelectrolyte collapse and reexpansion in the presence of multivalent counterions

We studied salt-induced changes in the viscosity of dilute solutions of a flexible polyelectrolyte, sodium poly(styrenesulfonate) (PSS), using particle tracking microrheology. It was found that PSS responds distinctively different to the presence of various trivalent cations. In addition to the well-known polyelectrolyte precipitation and redissolution, we also observed more subtle changes in solution viscosity, which can be attributed to chain collapse and reexpansion. In particular, the addition of indium chloride (InCl3) to PSS solutions leads to polyelectrolyte chain collapse at low salt concentrations, followed by chain reexpansion upon further increasing the salt concentration, as evidenced by an increase in relative viscosity of the polyelectrolyte solution; at even higher salt concentrations, the relative viscosity decreases and chains exhibit a secondary collapse The salt concentration at which the onset of reexpansion is observed is a function of the polyelectrolyte molecular weight and concentr...
Testing Formal Specifications to Detect Design Errors

Formal specification and verification techniques are now apused to increase the reliability of software systems. However, these proaches sometimes result in specifying systems that cannot be realized or that are not usable. This paper demonstrates why it is necessary to test specifications early in the software life cycle to guarantee a system that meets its critical requirements and that also provides the desired functionality. Definitions to provide the framework for classifying the validity of a functional requirement with respect to a formal specification tion are also introduced. Finally, the design of two tools for testing formal specifications is discussed.
A Lactation Measure of Somatic Cell Count

Abstract Adjustments and weights to combine individual sample day SCC into a lactation measure were developed from 182,446 Holstein lactation records completed in 1984 from herds primarily in the western United States. Data included 1,660,782 sample day SCC expressed as log base 2 scores. Stage of lactation effects were investigated within average lactation score. Curves for lactations with averages less than 3.5 were essentially identical, which indicated that effect of stage of lactation did not increase with average somatic cell score. Lactations with averages above 4.5 did not display the typical curve of an early minimum followed by a gradual increase and, therefore, were excluded from estimating effects of stage of lactation and season. Curve for lactations with an average somatic cell score of 4.0 was intermediate. Small season effects were detected; scores were lowest in February and March and highest in August, September, and October. Parities after first had similar curves for effect of stage of lactation, but first parity showed relatively little increase in late lactation. Weightings were developed to combine adjusted sample day scores into a lactation measure. Weights were squares of correlations (computed from sample days grouped by month) between adjusted score for a given sample day and average of adjusted scores from other sample days. Weights were lowest at start of lactation, highest in midlactation, and intermediate at end of lactation.
Hydrogen production by the unicellular, diazotrophic cyanobacterium Cyanothece sp. strain ATCC 51142 under conditions of continuous light.

We report on the hydrogen production properties of the unicellular, diazotrophic cyanobacterium Cyanothece sp. strain ATCC 51142. This organism has a versatile metabolism and can grow in the presence or absence of combined nitrogen and can grow photosynthetically or mixotrophically and heterotrophically in the presence of glycerol. The strain produces a bidirectional hydrogenase (encoded by the hox genes), an uptake hydrogenase (hupLS), and nitrogenase (nifHDK). We demonstrated hydrogen production by both the hydrogenase and the nitrogenase under appropriate metabolic conditions. The highest rates of hydrogen production were produced under nitrogen-fixing conditions when cells were grown and incubated under continuous light conditions, in either the presence or absence of glycerol. Under such nitrogen-fixing conditions, we have achieved rates of 300 mol H2/mg chloramphenicol (Chl)/hr during the first 24 h of incubation. The levels of H2 measured were dependent upon the incubation conditions, such as sparging with argon, which generated anaerobic conditions. We demonstrated that the same conditions led to high levels of H2 production and N2 fixation, indicating that low-oxygen conditions favor nitrogenase activity for both processes. The levels of hydrogen produced by the hydrogenase are much lower, typically 5 to 10 mol H2/mg Chl/hr. Hydrogenase activity was dependent upon electron transport through photosystem II (PS II), whereas nitrogenase activity was more dependent on PS I, as well as on respiration. Although cells do not double under the incubation conditions when sparged with argon to provide a low-oxygen environment, the cells are metabolically active, and hydrogen production can be inhibited by the addition of chloramphenicol to inhibit protein synthesis.
Intrapulse temporal and wavelength shifts of a high-power 2.1-µm Ho:YAG laser and their potential influence on atmospheric lidar measurements.

A high-power, flash-lamp-pumped, Q-switched Ho:YAG laser has been developed to produce up to 150 mJ in a 100-ns Q-switched pulse. The Ho laser was initially used in a direct detection lidar–differential absorption lidar (DIAL) system to measure vertical density profiles of aerosols and water vapor in the atmosphere. It was found, however, that the Ho laser operated simultaneously on two closely spaced spectral emission wavelengths (2.090 and 2.097 μm) and that the distribution of energy between the two wavelengths could change significantly on time scales of several seconds to minutes. Such intrapulse temporal and wavelength shifts were found to alter the atmospheric lidar return significantly because one of the laser lines coincided with a water vapor absorption line in the atmosphere. This laser spectral output problem was overcome by the use of intracavity etalons that controlled the laser spectral–temporal characteristics but reduced the laser output energy to approximately 75 mJ/pulse in a 100-ns pulse length. These results are important as they serve to point out the difficulties of developing and using a high-power 2.1-μm Ho laser for atmospheric lidar when high-resolution spectral and temporal characteristics can significantly influence the lidar return and be misinterpreted as resulting from atmospheric signals.
MANAGEMENT OF INDINAVIR ASSOCIATED NEPHROLITHIASIS

The treatment of human immunodeficiency virus (HIV) infection has improved greatly with the recent introduction of a new class of anti-HIV drugs, the protease inhibitors. The significance of these new agents derives from their ability to suppress dramatically HIV replication by inhibiting HIV protease, an enzyme needed to cleave functional proteins that render HIV infectious. Recent studies have shown that when one of these drugs, indinavir, is combined with 2 other drugs, plasma HIV viral load may decrease to undetectable levels.' Such dramatic results ensure that indinavir will have a dominant role in the treatment of the more than 1 million HIV infected individuals in the United States. The most significant side effect of indinavir, occurring in up to 4% of individuals, is nephrolithiasis.2 There is a dearth of detailed published information on the natural history and management of indinavir associated nephrolithiasis among patients enrolled in clinical trials and patients receiving indinavir as part of routine clinical care.
TRACING BURIAL HISTORY AND SEDIMENT RECYCLING IN A SHALLOW ESTUARINE SETTING (COPANO BAY, TEXAS) USING POSTMORTEM AGES OF THE BIVALVE MULINIA LATERALIS

ABSTRACT Age spectra of Mulinia lateralis shells from the top 0–10 cm of the sediment column in Copano Bay, Texas, show three distinct populations: a young population with a highly skewed distribution ranging from 0 to 1 years, a middle-aged population that is more symmetrical ranging from 1 to 10 years with a peak ∼ 4 years, and a small, very old population ranging from 100 to > 10000 years. The young population is interpreted to record the rapid loss of shells from the taphonomically active zone at or near the sediment surface. The middle-aged population is interpreted to record a sequestered population of shells that has had time to accumulate below the taphonomically active zone. Although surface age spectra differ among depositional environments and at different locations, both of these populations are present in all sampled facies at multiple locations within the bay, indicating that the overarching controls on surface age spectra affect the entire bay. The very old surface population is present onl...