Showing papers by "Pennsylvania State University published in 1982"
TL;DR: The reactions responsible for the biosynthesis and interconversion of the polyamines and their precursor putrescine are described and the means by which polyamine content can be varied in response to exogenous stimuli are discussed.
Abstract: Polyamines are ubiquitous organic cations of low molecular weight. The content of these amines is closely regulated by the cell according to the state of growth. The reactions responsible for the biosynthesis and interconversion of the polyamines and their precursor putrescine are described and the means by which polyamine content can be varied in response to exogenous stimuli are discussed. The role of polyamines in the cell cycle, cell division, tissue growth, and differentiation is considered. Recent studies using highly specific inhibitors of polyamine biosynthesis such as alpha-difluoromethylornithine to prevent accumulation of polyamines have indicated that the synthesis of polyamines is intimately associated with these processes. Such inhibitors have great potential for investigation of the cellular role of polyamines.
1,548 citations
TL;DR: The perovskite relaxor ferroelectric lead magnesium niobate (PbMg 1 3 Nb 2 3 O 3 ) is an important material because of its high dielectric constant and correspondingly large electrostrictive strains as mentioned in this paper.
1,465 citations
TL;DR: In this article, a one-dimensional planetary boundary layer (PBL) model is presented and verified using April 10, 1979 SESAME data, which contains two modules to account for two different regimes of turbulent mixing, and separate parameterizations are made for stable and unstable conditions, with a predictive slab model for surface temperature.
Abstract: A one-dimensional, planetary boundary layer (PBL) model is presented and verified using April 10, 1979 SESAME data. The model contains two modules to account for two different regimes of turbulent mixing. Separate parameterizations are made for stable and unstable conditions, with a predictive slab model for surface temperature. Atmospheric variables in the surface layer are calculated with a prognostic model, with moisture included in the coupled surface/PBL modeling. Sensitivity tests are performed for factors such as moisture availability, albedo, surface roughness, and thermal capacity, and a 24 hr simulation is summarized for day and night conditions. The comparison with the SESAME data comprises three hour intervals, using a time-dependent geostrophic wind. Close correlations were found with daytime conditions, but not in nighttime thermal structure, while the turbulence was faithfully predicted. Both geostrophic flow and surface characteristics were shown to have significant effects on the model predictions
1,011 citations
TL;DR: In this article, an intrinsic diversity ordering of communities is defined and is shown to be equivalent to stochastic ordering, and the sensitivity of an index to rare species is developed, culminating in a crossing-point theorem and a response theory to perturbations.
Abstract: This paper puts forth the view that diversity is an average property of a community and identifies that property as species rarity. An intrinsic diversity ordering of communities is defined and is shown to be equivalent to stochastic ordering. Also, the sensitivity of an index to rare species is developed, culminating in a crossing-point theorem and a response theory to perturbations. Diversity decompositions, analogous to the analysis of variance, are discussed for two-way classifications and mixtures. The paper concludes with a brief survey of genetic diversity, linguistic diversity, industrial concentration, and income inequality.
681 citations
TL;DR: In this article, a second order rate law was established for the partial exchange of sulfur isotopes between aqueous sulfates and sulfides in a Na-bearing H2-pH system.
586 citations
TL;DR: The relatively efficient running patterns used by the subjects during unrestricted running indicate either an adaption to the chosen stride length through training or a successful process of energy optimization.
Abstract: Ten recreational runners (mean VO2max 647 ml kg-1 min-1) underwent a 5-d acclimation period to treadmill running at a 7 min mile-1 pace (383 m s-1) for 30 min each day During these runs their freely chosen stride lengths were determined and expressed as a percentage of leg length (%LL) On two subsequent testing days stride length was systematically varied over a range of +/- 20% LL about the freely chosen value O2 uptake was determined by the Douglas Bag method All subjects exhibited a stride length of which O2 uptake was minimized, although the individual profiles varied considerably The mean increases in VO2 were 26 and 34 ml kg-1 min-1 at the short- and long-stride length extremes, respectively During unrestricted running deviations from optimal stride length caused a mean increase in VO2 of 02 ml kg-1 min-1 The relatively efficient running patterns used by the subjects during unrestricted running indicate either an adaption to the chosen stride length through training or a successful process of energy optimization
556 citations
TL;DR: A link between IL 1 and IL 2 is an essential element in the T cell activation sequence because it involves the conversion of a primary macrophage-derived maturational signal into a secondary T cell-derived proliferative signal that results in the amplification of specific immune responses.
Abstract: The antigen-specific activation of T cells is dependent upon two distinct but interdependent macrophage signals. Macrophages are required to bin^, process, and present antigens in an immunogcnic form to T cells (Schwartz et ul. 1978). This function of the macrophage is genetically-restricted and is a property of an la positive subpopulation of macrophages. The second macfophage-derived T cell activating signal is a Iow molecular weight antigen-non-specific peptide termed interleukin 1 (IL I) (Aarden et al. 1979) that is apparently produced by all macrophages (Oppenheim etal. 1979). As will be discussed in this review, IL I appears to act as a maturational signal, preparing T cells to respond to antigens or secondary mediator signals. One of the major activities of interleukin 1 is to induce the synthesis and secretion of the T cell-derived mitogenic lymphokine, interleukin 2 (IL2) (Farrar et al. 1980b, Smith et al. 1980, Larsson et al. 1980). This link between IL 1 and IL 2 is an essential element in the T cell activation sequence because it involves the conversion of a primary macrophage-derived maturational signal into a secondary T cell-derived proliferative signal that results in the amplification of specific immune responses.
530 citations
TL;DR: In this article, the validity, adverse impact and fairness of eight categories of alternatives were reviewed and the feasibility of operational use of each type of alternative in an employment setting was also discussed.
Abstract: Despite extensive evidence that tests are valid for employee selection, Federal Guidelines have urged employers to seek alternative selection procedures that are equally valid but have less adverse impact on minorities. Research on the validity, adverse impact and fairness of eight categories of alternatives was reviewed. Feasibility of operational use of each type of alternative in an employment setting was also discussed. Only biodata and peer evaluation were supported as having validities substantially equal to those for standardized tests. Previous reviews and more recent research indicated that interviews, self-assessments, reference checks, academic achievement, expert judgment and projective techniques had levels of validity generally below those reported for tests. Data, where available, offered no clear indication that any of the alternatives met the criterion of having equal validity with less adverse impact. Results are discussed and several additional promising alternatives are described.
450 citations
TL;DR: In this article, theoretical and experimental results concerning two sources of error in the determination of specific contact resistance of ohmic contacts to semiconductor device structures that utilize circular test patterns with varying gap length are presented.
Abstract: This paper presents theoretical and experimental results concerning two sources of error in the determination of specific contact resistance of ohmic contacts to semiconductor device structures that utilize circular test patterns with varying gap length. It is shown that the potential drop vs gap length data cannot be usually represented by a straight line and a non-zero metal overlay sheet resistance can significantly alter the effective contact resistance value.
429 citations
TL;DR: The kinetic mechanism for adenosine cyclic 3',5'-monophosphate dependent protein kinase was determined from initial velocity studies in the absence and presence of the product MgADP and dead-end inhibitors and the binding of Mg2+ to a second site was characterized.
Abstract: The kinetic mechanism for adenosine cyclic 3',5'-monophosphate dependent protein kinase was determined from initial velocity studies in the absence and presence of the product MgADP and dead-end inhibitors. Data are consistent with random addition of MgATP and Ser-peptide and ordered release of phospho-Ser-peptide and MgADP with a dead-end E-MgADP-Ser-peptide complex. In addition to the metal required for the nucleotide, we also characterized the binding of Mg2+ to a second site. Increasing the Mg2+ results in a 5-6-fold decrease in V,,, in the presence or absence of 0.1 M KCl. There is a 5-fold increase in V/KMgATP in the absence of KCl and a 13-fold increase in V/KMdTP at 0.1 M KC1. The effect of increasing free Mg2+ on V,,, and V/K was also obtained with MgITP (20% the V,,, with MgATP) and MgGTP (10% the V,,, with MgATP) as substrates. The dissociation constant for Mg2+ from E-Ser-peptide-Mg2+ and central complexes is 2-3 mM. At low concentrations of free Adenosine cyclic 3',5'-monophosphate dependent protein kinase catalyzes the phorphorylation of a variety of proteins according to
366 citations
TL;DR: In this paper, a method was developed for directly converting esters to amides using reagents derived from the reaction of trimethylaluminum with ammonium chloride, methylamine hydrochloride or dimethylamine hydchloride.
TL;DR: Yeast transformed with GAL4-bearing plasmid become constitutive for expression of the galactose/melibiose genes, even in normally repressing (glucose) medium, indicating that the repressing effects of glucose, at least in part, are mediated by the product of the negative regulatory gene GAL80.
Abstract: GAL4 is a classically defined positive regulatory gene controlling the five inducible structural genes of galactose/melibiose utilization in yeast. The positive regulatory function of the GAL4 gene product in turn is controlled by the product of another gene, the negative regulator GAL80. We have cloned a 3.1-kilobase fragment containing GAL4 by homologous complementation using the multicopy chimeric vector YEp24 and demonstrated that multiple copies of GAL4 in yeast have pronounced dosage effects on the expression of the structural genes. Yeast transformed with GAL4-bearing plasmid become constitutive for expression of the galactose/melibiose genes, even in normally repressing (glucose) medium. Multiple copies of the GAL4 plasmid also increase expression of the structural genes in inducing (galactose) medium and can partially overcome the effects of a dominant super-repressor mutant, GAL80S. Using an internal deletion in GAL4, we have demonstrated that these dosage effects are due to overproduction of GAL4 positive regulatory product rather than an effect of the flanking sequences titrating out a negative regulator. These results point to the importance of competitive interplay between the positive and negative regulatory proteins in the control of this system. We have also used the dosage effect of GAL4 plasmid in combination with different GAL4 and GAL80 alleles to create new phenotypes. We interpret these phenotypes as indicating that (i) the repressing effects of glucose, at least in part, are mediated by the product of the negative regulatory gene, GAL80, and (ii) the GAL80 protein may have specific interactions with the control regions of the structural genes.
TL;DR: Simpson's Paradox in Real Life as mentioned in this paper is a well-known example of the Simpson paradox in real life, and it has been studied extensively in the literature. The American Statistician: Vol. 36, No. 1, pp. 46-48.
Abstract: (1982). Simpson's Paradox in Real Life. The American Statistician: Vol. 36, No. 1, pp. 46-48.
TL;DR: Algorithms are presented that run in time which depends nontrivially on the rank k of the element to be selected and which is sublinear with respect to set cardinality, and all bounds are shown to be optimal to within a constant multiplicative factor.
TL;DR: Solutions to this family of convex programs are shown to be Nash equilibria in the formal sense of N person games, which leads to a mathematical programming-based algorithm for determining an oligopolistic market equilibrium.
Abstract: During the past several years it has become increasingly common to use mathematical programming methods for deriving economic equilibria of supply and demand. Well-defined approaches exist for the case of a single firm (monopoly) and for the case of many firms (perfect competition). In this paper a certain family of convex programs is formulated to determine equilibria for the case of a few firms (oligopoly). Solutions to this family of convex programs are shown to be Nash equilibria in the formal sense ofN person games. This equivalence leads to a mathematical programming-based algorithm for determining an oligopolistic market equilibrium.
TL;DR: In this article, a free-volume theory of polymer-solvent diffusion coefficients is proposed and evaluated using experimental diffusivity data collected over wide temperature and concentration ranges, showing that the theory accurately predicts the large temperature variations typically observed for polymer solvents diffusion coefficients.
Abstract: A revised version of a recently proposed free-volume theory of polymer-solvent diffusion is introduced and evaluated using experimental diffusivity data collected over wide temperature and concentration ranges. The theory accurately predicts the large temperature and concentration variations typically observed for polymer-solvent diffusion coefficients.
TL;DR: In this article, the Bekenstein-Parker Gaussian pathintegral approximation is used to evaluate the thermal propagator for a conformally invariant scalar field in an ultrastatic metric.
Abstract: The Bekenstein-Parker Gaussian path-integral approximation is used to evaluate the thermal propagator for a conformally invariant scalar field in an ultrastatic metric If the ultrastatic metric is conformal to a static Einstein metric, the trace anomaly vanishes and the Gaussian approximation is especially good One then gets the ordinary flat-space expressions for the renormalized mean-square field and stress-energy tensor in the ultrastatic metric Explicit formulas for the changes in $〈{\ensuremath{\varphi}}^{2}〉$ and $〈{T}_{\ensuremath{\mu}\ensuremath{
u}}〉$ resulting from a conformal transformation of an arbitrary metric are found and used to take the Gaussian approximations for these quantities in the ultrastatic metric over to the Einstein metric The result for $〈{\ensuremath{\varphi}}^{2}〉$ is exact for de Sitter space and agrees closely with the numerical calculations of Fawcett and Whiting in the Schwarzschild metric The result for $〈{T}_{\ensuremath{\mu}\ensuremath{
u}}〉$ is exact in de Sitter space and the Nariai metric and is close to Candelas's values on the bifurcation two-sphere in the Schwarzschild metric Thus one gets a good closed-form approximation for the energy density and stresses of a conformal scalar field in the Hartle-Hawking state everywhere outside a static black hole
TL;DR: Two fundamentally different ways of conceptualizing and measuring firm diversity are identified, their strengths and weaknesses discussed, and their suitability for investigating commonly asked questions evaluated as mentioned in this paper, and a strategic measure of diversity is recommended.
Abstract: Two fundamentally different ways of conceptualizing and measuring firm diversity—by business count and by strategy—are identified, their strengths and weaknesses discussed, and their suitability for investigating commonly asked questions evaluated. A business count measure is claimed to be suitable for research comparing diversified and nondiversified firms but not for investigating differences among diversified firms. For the latter task, a strategic measure of diversity is recommended.
TL;DR: In this article, the catalytic capacity of the (Pd(CH/sub 3/CN)/sub 4/)(BF/ sub 4/)/sub 2/n-triphenylphosphine n = (1-3) was demonstrated for copolymerization of CO with ethylene and other alkenes under very mild conditions.
Abstract: The catalyst, (Pd(CH/sub 3/CN)/sub 4/)(BF/sub 4/)/sub 2/.n-triphenylphosphine n = (1-3), demonstrated the capacity to mediate the copolymerization of CO with ethylene and other alkenes under very mild conditions. The reaction of ethylene (350 psi), dissolved in acetonitrile, and CO(350 psi) was performed at 25/sup 0/C for 1 d. The copolymerizations of CO(800 psi) with norbornadiene and norbornylene were performed at 60/sup 0/C. The structures of the copolymers were studied by NMR. 9 references, 1 figure.
TL;DR: The growth retardation was greatest when women were underweight pregravid and had a low pregnancy weight gain, when they were hypertensive, or when the work required standing, and the frequency of large placental infarcts progressively increased when women continued stand-up work into late gestation.
Abstract: In order to determine whether pregnancy outcome was altered when women were employed outside their homes, 7,722 pregnancies were analyzed. Gestations were not shortened but newborns of women who worked in the third trimester weighed 150 to 400 gm less than newborns of mothers who remained at home. The growth retardation was greatest when women were underweight pregravid and had a low pregnancy weight gain, when they were hypertensive, or when the work required standing. The growth retardation remained after the data were stratified by race, socioeconomic status, and other maternal factors that commonly influence fetal growth. The frequency of large placental infarcts progressively increased when women continued stand-up work into late gestation. Such infarcts reached a peak of 250/1,000 births after the 37th week of gestation in stand-up workers. Low uteroplacental blood flow is a likely explanation for both the fetal growth retardation and the large placental infarcts.
TL;DR: In the 18th-century frontiers of the Virginia highland, weary travelers were fortunate to arrive by nightfall at a log cabin called a “necessary.” The cabin provided the bare essentials of shelter, food and drink, enabling them to continue the journey on the next day into the wilderness.
Abstract: On the 18th-century frontiers of the Virginia highland, weary travelers were fortunate to arrive by nightfall at a log cabin called a “necessary.” The “necessary” provided the bare essentials of shelter, food and drink, enabling them to continue the journey on the next day into the wilderness. The concepts I shall discuss are needed in psychology’s “necessary” to enable the difficult journey toward understanding the psychology of being woman in a social context. Today’s psychology is more like a luxury hotel, offering the traveler a superabundance of conceptual tools. I would perform no service by adding new concepts to the bewildering array that already includes gender identity, sex identity, sex roles and sex role identities, masculinity, femininity, sex-reversed identity, androgyny (high and “undifferentiated”), etc. The plethora of concepts is complicated by the several definitions given to each by different authors. “Gender identity” means different things to different people. Some broad definitions encompass everything it means to feel, think and act like a woman or man. More specific definitions are modeled on social stereotypes of masculinity or femininity and on androgyny. Other normative definitions require acceptance of one’s biological sexuality, hence presumably of certain social meanings attached to it. Our concepts should be capable of handling such evaluative issues, but they should not be evaluative concepts. Therefore, I will start naively with the first needed concept, and ask what gender is. Gender is a
TL;DR: This article classified major works on suicide into four analytic categories according to their theoretical emphasis: cultural, economic, modernization, and social integration perspectives, and assessed the research under these paradigms in terms of four themes.
Abstract: Major works on suicide are reviewed and classified into four analytic categories according to their theoretical emphasis: cultural, economic, modernization, and social integration perspectives. The research under these paradigms is assessed in terms of four themes. First, attention is drawn to research evidence that questions traditional theories. An example is Durkheim's position on social class and suicide. Second, the review notes several new theories including Phillips’ imitation thesis and the author's own model of migration's effects on suicide. Third, the paper observes and reviews explanations of new trends in suicide rates such as the rapid increase in youth suicide and the decline in suicide among the elderly. Finally, the review calls attention to explanations of suicide, such as that linking suicide to low marital solidarity, that have withstood the test of the more rigorous empirical testing of recent times.
TL;DR: For instance, this article found that subjects who were required to present a speech after their sleep period and told the topic of the speech required significantly longer to fall asleep and obtained less sleep than subjects in two control conditions.
TL;DR: The work behavior of five elementary school principals was examined using Mintzberg's structured observation technique as mentioned in this paper, and the principals' activities exhibited the intensity, variety, and fragmentation typical of administrator work.
Abstract: The work behavior of five elementary school principals was examined using Mintzberg's structured observation technique. The principals' activities exhibited the intensity, variety, and fragmentation typical of administrator work. Compared with secondary principals in an earlier study, the elementary principals' pace was less hectic, and they spent more time on the instructional program. They also exhibited many individual differences. The authors conclude with a consideration of the limitations of structured observation. The article is an expanded version of a paper presented at the Annual Meeting of the American Educational Research Association, New York Citv, March 1982.
TL;DR: The results suggest that a significant fraction of Ca2+ flux across the MEL cell plasma membrane occurs via a Na+/Ca2+ antiport system and that amiloride prevents differentiation by blocking Ca2-inhibitable influx through this system.
TL;DR: An effective regimen to inhibit estrogen production in postmenopausal women using aminoglutethimide and replacement glucocorticoid is developed, and plasma and urinary estrogen levels fell equally in responder versus nonresponder groups whereas androgen levels declined less in patients with progressive disease.
Abstract: Hormone-dependent breast carcinomas respond to deprivation of biologically active estrogens with objectively quantifiable tumor regression. Aminoglutethimide, a known inhibitor of steroid ...
TL;DR: Goodman as discussed by the authors presented a class of models for the analysis of association between two discrete, ordinal variables, measured in terms of the odds ratios in 2 × 2 subtables formed from adjacent rows and adjacent columns of the cross-classification.
Abstract: Goodman recently presented a class of models for the analysis of association between two discrete, ordinal variables The association was measured in terms of the odds ratios in 2 × 2 subtables formed from adjacent rows and adjacent columns of the cross-classification, and models were devised that allowed the odds ratios to depend on an overall effect, on row effects, on column effects, and on other effects This article presents some generalizations of this approach appropriate for multiway cross-classifications, including (a) models for the analysis of conditional association, (b) models for the analysis of partial association, and (c) models for the analysis of symmetric association Three cross-classifications are analyzed with these models and methods, and rather simple interpretations of the association in each are provided
TL;DR: It was demonstrated that tsB5 enters human embryonic lung (HEL) cells more rapidly than KOS, another strain of HSV-1, and DNA sequences that specify a functional domain for virus entry were localized to the nucleotide sequences between the two mutations.
TL;DR: The assumption that energy development causes social disruption in western communities is based on undocumented assertions, questionable interpretations of evidence, and superficial analyses as discussed by the authors. But the assumption is not supported by empirical evidence.
Abstract: The assumption that energy development causes social disruption in western communities is based on undocumented assertions, questionable interpretations of evidence, and superficial analyses. Theor...