Showing papers by "Pennsylvania State University published in 1988"

A self-report measure of pubertal status: Reliability, validity, and initial norms.

Abstract: Puberty is a central process in the complex set of changes that constitutes the transition from childhood to adolescence. Research on the role of pubertal change in this transition has been impeded by the difficulty of assessing puberty in ways acceptable to young adolescents and others involved. Addressing this problem, this paper describes and presents norms for a selfreport measure of pubertal status. The measure was used twice annually over a period of three years in a longitudinal study of 335 young adolescent boys and girls. Data on a longitudinal subsample of 253 subjects are reported. The scale shows good reliability, as indicated by coefficient alpha. In addition, several sources of data suggest that these reports are valid. The availability of such a measure is important for studies, such as those based in schools, in which more direct measures of puberty may not be possible.

Optimal alignments in linear space.

Abstract: Space, not time, is often the limiting factor when computing optimal sequence alignments, and a number of recent papers in the biology literature have proposed space-saving strategies. However, a 1975 computer science paper by Hirschberg presented a method that is superior to the new proposals, both in theory and in practice. The goal of this paper is to give Hirschberg's idea the visibility it deserves by developing a linear-space version ofGotoh's algorithm, which accommodates affine gap penalties. A portable C-software package implementing this algorithm is available on the BIONET free of charge.

Narrative and the Self as Relationship

Abstract: Publisher Summary This chapter explores the nature of stories of self, both as they are told and lived in social life. It examines the story form—or more formally, the structure of narrative accounts. It then describes the way narratives of the self are constructed within social life and the uses to which they are put. As story advances, it become increasingly clear that narratives of the self are not fundamentally possessions of the individual; rather they are products of social interchange—possessions of the socius. This analysis set the stage for a discussion of lived narrative. The chapter proposes the traditional concept of individual selves is fundamentally problematic. What have served as individual traits, mental processes, or personal characteristics can promisingly be viewed as the constituents of relational forms. The form of these relationships is that of the narrative sequence. Thus, by the end of story it can be found that the individual self has all but vanished into the world of relationship.

Abandoned pastures in eastern Amazonia. I. Patterns of plant succession

Abstract: (1) Vegetation composition, structure, and biomass accumulation were studied on thirteen forest sites that had been cut and burned, used as cattle pasture, and then abandoned in the eastern Amazon near Paragominas, Para, Brazil. (2) The study sites were of two ages (two to four years and seven to eight years) and had received light, medium or heavy use for up to thirteen years. (3) Forest regenerated vigorously on sites of previously light use. Above-ground biomass accumulation averaged 10 t ha-' y-1 or 80 t after eight years (roughly onequarter of mature forest levels). Tree species richness was also high (about 20 per 100 mi2) and almost all species also occurred in native forest. Moderately grazed pastures also developed forest but biomass accumulation was only 5 t ha'-I y. Tree species richness was also lower than on light-use sites and there were fewer forest trees. Abandoned pastures subjected to heavy use had the least distinct patterns of succession. The single eight-year-old site was dominated by grasses and forbs with fewer than one tree per 100 m2 and an above-ground biomass accumulation of 0 6 t ha-' y1, a value only about 6% of that found on light-use sites. (4) The light-use sites had significantly higher biomass and species richness in both ageclasses than either moderateor heavy-use sites. Site age was a good predictor of aboveground biomass accumulation on lightand moderate-use sites, but not on heavy-use sites. (5) These Amazon ecosystems generally can recover after large-scale pasture disturbances. Only where land has been used too intensively for long periods is reforestation uncertain, but probably less than 10% of the pasture land in northern Para has degraded to this level. Nevertheless, the re-growth forest, regardless of pasture-use history, will not necessarily have the same characteristics of physiognomy or species composition as that originally occupying the site. Moreover, as burning becomes more prevalent in eastern Amazonia, abandoned sites may not develop into forest and the irreversible degradation of the entire regional ecosystem must be contemplated.

Graph-based heuristics for recognition of machined features from a 3D solid model

Abstract: The internal representation of the solid modeller provides a description of parts which when used directly is useful for automation of the process planning function. So that the CAD model can be used to provide the information required for manufacturing, techniques to improve machine understanding of the part as required for manufacturing are needed. This paper presents the development of the concept attributed adjacency graph (AAG) for the recognition of machined features from a 3D boundary representation of a solid. Current implementation of the feature recogniser is limited to polyhedral features such as pockets, slots, steps, blind steps, blind slots, and polyhedral holes. Sample results that show the capabilities of the system are presented.

A robust algorithm for text string separation from mixed text/graphics images

Abstract: The development and implementation of an algorithm for automated text string separation that is relatively independent of changes in text font style and size and of string orientation are described. It is intended for use in an automated system for document analysis. The principal parts of the algorithm are the generation of connected components and the application of the Hough transform in order to group components into logical character strings that can then be separated from the graphics. The algorithm outputs two images, one containing text strings and the other graphics. These images can then be processed by suitable character recognition and graphics recognition systems. The performance of the algorithm, both in terms of its effectiveness and computational efficiency, was evaluated using several test images and showed superior performance compared to other techniques. >

Helix signals in proteins

Abstract: The alpha helix, first proposed by Pauling and co-workers, is a hallmark of protein structure, and much effort has been directed toward understanding which sequences can form helices. The helix hypothesis, introduced here, provides a tentative answer to this question. The hypothesis states that a necessary condition for helix formation is the presence of residues flanking the helix termini whose side chains can form hydrogen bonds with the initial four-helix greater than N-H groups and final four-helix greater than C-O groups; these eight groups would otherwise lack intrahelical partners. This simple hypothesis implies the existence of a stereochemical code in which certain sequences have the hydrogen-bonding capacity to function as helix boundaries and thereby enable the helix to form autonomously. The three-dimensional structure of a protein is a consequence of the genetic code, but the rules relating sequence to structure are still unknown. The ensuing analysis supports the idea that a stereochemical code for the alpha helix resides in its boundary residues.

Integrated Communication and Control Systems: Part I—Analysis

Abstract: The paper presents the results of an ICCS analysis focusing on discrete-time control systems subject to time-varying delays. The present analytical technique is applicable to integrated dynamic systems such as those encountered in advanced aircraft, spacecraft, and the real-time control of robots and machine tools via a high-speed network within an autonomous manufacturing environment. The significance of data latency and missynchronization between individual system components in ICCS networks is discussed in view of the time-varying delays.

Antecedents of Organizational Slack

Abstract: Organizational slack has been widely discussed, but only in its role as an antecedent of performance, political behavior, bankruptcy, and other phenomena. A model that describes the antecedents of organizational slack is presented here. It contains three sets of predictors: environmental contingencies, organizational characteristics, and the values and beliefs of dominant coalition. Hypotheses detailing how each set of predictors leads to the development of different levels and types of slack resources are presented.

Changes in Wildlife Communities Near Edges

Abstract: Wildlife managers and land managers have traditionally considered edges as beneficial to wildlife because species diversity generally increases near habitat edges. Explanations for this edge effect include greater vegetative complexity at edges or the simultaneous availability of more than one landscape element. However, edges can have negative consequences for wildlife by modifying distribution and dispersal and by increasing incidence of nest predation and parasitism Edges also may be detrimental to species requiring large undisturbed areas because increases in edge generally result in concommitant reductions in size and possible isolation of patches and corridots. Thus, both wildlife and land managers should be cautious when describing the benefits of edges to wildlife: particularly when dealing with species that require forest interiors. Changes in wildlife communities associated with habitat edges are not easily assessed because defining edge species and measuring edge dimensions can be difficult in field studies Also, there is no general consensus as to how edge effect is best measured. Well-designed long-term studies of edges in various landscapes are needed (1) to better understand the positive and negative impacts of edges on wildlife communities, guilds, or key species, and (2) to effectively quantify edge effect and thereby develop management recommendations to improve the quality of edges for wildlife. Additional studies of edge effect are timely because greater amounts of edge will continue to be created in future landscapes due to extensive agriculture and other land-use-practices, and because developing knowledge in conservation biology and landscape ecology will facilitate multidisciplinary approaches to edge and landscape management for the benefit of wildlife.

Effect of metabolic products of muscular contraction on discharge of group III and IV afferents

Abstract: Static muscular contraction has been firmly established to reflexly increase cardiovascular and ventilatory function. Although group III and IV fibers with endings in muscle have been shown to comp...

Estimated prevalence of anabolic steroid use among male high school seniors

Abstract: The use of anabolic-androgenic steroids (AS) is perceived by the media, by segments of the sports medicine and athletic communities, and by the public to have grown to epidemic proportions. Unfortunately, the incidence and prevalence of AS use among elite, amateur, and recreational athletes is poorly documented. This study was designed to help identify AS use patterns among the male portion of the general adolescent population. The overall participation rate on a schoolwide basis was 68.7% and on an individual basis reached 50.3%. Participants in this investigation were 12th-grade male students (N = 3403) in 46 private and public high schools across the nation who completed a questionnaire that established current or previous use of AS as well as user and nonuser characteristics. Results indicate that 6.6% of 12th grade male students use or have used AS and that over two thirds of the user group initiated use when they were 16 years of age or younger. Approximately 21% of users reported that a health professional was their primary source. The evidence indicates that educational intervention strategies should begin as early as junior high school; the intervention should not be directed only toward those individuals who participate in school-based athletics. (JAMA1988;260:3441-3445)

A Model of CEO Dismissal

Abstract: A model is presented in which social and political factors are used to predict the likelihood of a CEO's dismissal. Although an organization's performance affects dismissal of a CEO, it is argued that the link is not direct. It is mediated by four constructs: (a) the board of directors' expectations and attributions, (b) the board's allegiances and values, (c) the availability of alternative candidates for CEO, and (d) the power of the incumbent CEO. Observable determinants of these constructs are identified It is suggested that these determinants can be found in characteristics of the board, the organization, the industry, the CEO, and the CEO's predecessor.

A method for prediction of volcanic eruptions

Abstract: The relationship Ω·–α Ω¨ – A = 0 describes the behaviour of materials in terminal stages of failure, where Ω is an observable quantity such as strain, and A and α are empirical constants. Drawing on analogies between failure mechanics and eruption processes at volcanoes, Ω is interpreted in terms of conventional geodetic, seismic or geochemical observations. Manipulation of Ω provides a consistent analytical basis for eruption prediction.

Surface tension of binary metal—surface active solute systems under conditions relevant to welding metallurgy

Abstract: Since the fluid flow, heat transfer, and the resulting weld properties are significantly affected by interfacial tension driven flow, the variation of interfacial tension in dilute binary solutions is studied as a function of both composition and temperature. Entropy and enthalpy of adsorption of surface active components such as oxygen, sulfur, selenium, and tellurium in Fe-O, Fe-S, Fe-Se, Cu-O, Cu-S, Cu-Se, Cu-Te, Ag-O, and Sn-Te systems were calculated from the analysis of the published data on interfacial tension of these systems. For these calculations, a formalism based on the combination of Gibbs and Langmuir adsorption isotherms was used. Interfacial tensions in Cr-O, Co-S, and Ni-S systems, where the data are scarce, were predicted by using certain approximations. The computed values were found to be in reasonable agreement with the data available in the literature. Temperature coefficients of interfacial tensions were calculated for several binary systems. It was demonstrated that in dilute solutions, the temperature coefficient of interfacial tension is strongly influenced by the heat of adsorption which, in turn, is influenced by the difference in electronegativity between the solute and solvent ions.

Role of glycoprotein B of herpes simplex virus type 1 in viral entry and cell fusion.

Abstract: Glycoprotein B (gB) of herpes simplex virus type 1 is an envelope protein that is essential for viral growth. We previously reported the isolation of two gB-null viruses, which form gB-free virions in nonpermissive cells. In the present study, these gB-free virions were shown to bind to the cell surface at the same rate as the wild-type virus. They failed, however, to form plaques and to synthesize virus-specific proteins upon infection. Their plating efficiency was significantly enhanced by treatment with polyethylene glycol, a membrane fusion agent. Therefore, gB is required in a stage after viral attachment but before the expression of the virus-specific proteins. A gB-null syncytial virus was isolated, which contained a gB defect and a syncytial mutation in another genetic locus. It caused complete fusion of gB-transformed cells but no fusion on untransformed cells, indicating the essential role of gB in virus-induced cell fusion. Mutations located at two independent sites in the cytoplasmic domain of gB were transferred to viral DNA and shown to confer a syncytial phenotype to the virus. A transient-expression assay was developed to determine the ability of a set of plasmids containing addition and nonsense mutations in the gB gene to complement the cell-fusion defect in the gB-null syncytial virus. Mutations in plasmids, including those located in the extracytoplasmic domain of gB, were identified that reduced the fusion activity of gB. Therefore, gB contains different functional regions responsible for fusion induction and its inhibition.

Contrasting actions of tamoxifen on endometrial and breast tumor growth in the athymic mouse.

Abstract: The effects of the antiestrogen tamoxifen (TAM) on the growth of two hormone-sensitive human tumors have been examined in athymic mice. The endometrial tumor, EnCa101, was stimulated to grow by TAM either alone or when combined with estradiol. This contrasted with the non-stimulation of the breast tumor, MCF-7, by TAM alone and the antagonist action of TAM on estradiol-stimulated growth of MCF-7 tumors. The individual tumor responses were observed even when the two tumor types were implanted on opposite sides of the same animal. This suggests that host metabolism of TAM does not dictate tissue response. The conclusion is supported by the finding of very similar patterns of metabolites in the two tumors after administration of [ ring - 3 H]TAM. Tissue metabolism therefore is unlikely to be involved. Progesterone receptor levels were higher in estradiol (376 ± 35 fmol/mg cytosol protein)- or TAM (317 ± 37 fmol/mg cytosol protein)-stimulated EnCa101 tumors than control (42 ± 5 fmol/mg cytosol protein) and increased further with combined treatment (485 ± 75 fmol/mg cytosol protein). Estrogen receptor levels, however, were lower in estradiol (45 ± 11 fmol/mg cytosol protein)-treated tumors than control (92 ± 13 fmol/mg cytosol protein) but higher than control in TAM (200 ± 15 fmol/mg cytosol protein)-treated tumors. Tumors grown with estradiol and TAM had lower estrogen receptor levels (130 ± 7 fmol/mg cytosol protein) than tumors grown with TAM alone. Estrogen receptor levels indicate that TAM may not be acting exactly as estradiol in the EnCa101 tumor. Overall, these findings suggest that the disparate pharmacology of TAM is a tissue-specific phenomenon.

Dyson's crank of a partition

Abstract: holds. He was thus led to conjecture the existence of some other partition statistic (which he called the crank); this unknown statistic should provide a combinatorial interpretation of ^-p(lln + 6) in the same way that (1.1) and (1.2) treat the primes 5 and 7. In [4, 5], one of us was able to find a crank relative to vector partitions as follows: For a partition 7r, let #(7r) be the number of parts of ir and cr{n) be the sum of the parts of ir (or the number ir is partitioning) with the convention #( ) = ) = 0 for the empty partition 0, of 0. Let

Vegetation Dynamics in Amazonian Treefall Gaps

Abstract: In a 1 -ha plot of old-growth tierra firme forest near San Carlos de Rio Negro, Venezuela (northwest Amazon Basin), 88 trees - 10 cm dbh out of 786 died over a 10-yr period. Most deaths resulted in the formation of small (5-100 m2) canopy openings (gaps). Occasionally, large gaps are formed in this region when strong winds topple many trees together. In five small (single-treefall) gaps and one large (multiple-treefall) gap we studied changes in soil fertility and nutrient leaching, and also plant establishment, mortality, and growth during the first 4 yr following gap formation. Gaps were divided into four zones, or mi- crohabitats: a trunk zone, an open zone (between bole and forest edge), a crown zone, and a root-pit zone. Sampling was conducted in each microhabitat. Soil nutrient levels in single-treefall gaps did not differ in a predictable fashion in response to microhabitat within gap or gap age. Moreover, except for a small, short-term increase in NO3-N, leaching losses from single-treefall gaps did not differ from forest levels. Advance regeneration plays a dominant role in treefall gap succession at San Carlos. Under closed forest, advance regeneration has a mean annual survivorship of - 80%; height growth is only a few centimetres a year, and leaf retention times frequently exceed 4 yr. Four years after gap formation, advance regeneration accounted for 97% of all trees ?-1 m tall in the single-treefall gaps and 83% of all trees in the multiple-treefall gap. Almost all trees in both gap types were of primary forest species; pioneer trees comprised only a small fraction of the regrowth. In general, microhabitat within gaps did not influence plant density, or plant estab- lishment and mortality patterns. However, mortality was much higher for individuals that germinated after gap formation than for individuals present as advance regeneration. Plant growth within treefall gaps was influenced by gap size, gap microhabitat type, gap age, and plant size. Seedlings and saplings of forest trees in the multiple-treefall gap grew three times as fast as those in the single-treefall gaps. Within single-treefall gaps, height growth was greater in the trunk and open zones than in the crown zone, and trees generally grew more slowly as gaps aged. Furthermore, tree growth was positively correlated with tree size, causing the size differential between trees of different heights to expand as gaps aged. At San Carlos, tree seedlings do not grow to the canopy during a single gap event; rather, canopy closure occurs by growth of larger pole-sized trees that survived treefalls or by lateral expansion of bordering subcanopy trees. Our results indicate that neither gap size, microhabitat within gaps, nor gap age have measurable effects on nutrient loss, nor do they appear to affect plant density, plant estab- lishment, or plant mortality. Size, microhabitat, and temporal affects are minimized, in large part, because of the great importance of advance regeneration in gap succession.

Nonmaternal care in the first year of life and the security of infant-parent attachment.

Abstract: Evidence from 2 longitudinal studies of infant and family development was combined and examined in order to determine if experience of extensive nonmaternal care in the first year is associated with heightened risk of insecure infant-mother attachment and, in the case of sons, insecure infant-father attachment. Analysis of data obtained during Strange Situation assessments conducted when infants were 12 and 13 months of age revealed that infants exposed to 20 or more hours of care per week displayed more avoidance of mother on reunion and were more likely to be classified as insecurely attached to her than infants with less than 20 hours of care per week. Sons whose mothers were employed on a full-time basis (greater than 35 hours per week) were more likely to be classified as insecure in their attachments to their fathers than all other boys, and, as a result, sons with 20 or more hours of nonmaternal care per week were more likely to be insecurely attached to both parents and less likely to be securely attached to both parents than other boys. A secondary analysis of infants with extensive care experience who did and did not develop insecure attachment relationships with their mothers highlights several conditions under which the risk of insecurity is elevated or reduced. Both sets of findings are considered in terms of other research and the context in which infant day-care is currently experienced in the United States.

Growth mechanism of vapor-deposited diamond

Abstract: An elementary-reaction mechanism of diamond growth by a vapor deposition process is proposed. The central postulate is that the main monomer growth species is acetylene. The mechanism basically consists of two alternating steps: surface activation by H abstraction of a hydrogen atom from a surface carbon and the addition of one or two acetylene molecules. During the addition reaction cycle a number of solid C–C bonds is formed and hydrogen atoms migrate from a lower to an upper surface layer. The mechanism is in general agreement with the macroscopic views of the Russian researchers and is consistent with the numerous experimental observations reported in the literature.

An improved spatial smoothing technique for bearing estimation in a multipath environment

Abstract: It is well known that signal subspace algorithms perform poorly when coherent or highly correlated signals are present. Recently, the so-called spatial smoothing technique was devised to preprocess the array covariance matrix so that signal subspace algorithms can be applied irrespective of the signal correlation. Unfortunately, the application of this technique reduces the effective aperture of the array. A modified spatial smoothing technique that is capable of increasing the effective aperture of the array over that of conventional spatial smoothing methods is explored. It is shown that under certain conditions, the modified algorithm may fail to yield the desired increase in array aperture, and some simulation results concerning the sensitivity of the modified spatial smoothing algorithm to these conditions are provided. >

Crystals in gels and Liesegang rings

Abstract: Providing the first comprehensive overview of the method of crystal growth in gels, Professor Henisch reviews the field, covering the underlying physics as well as the empirical experience of growth techniques accumulated over the past century. In addition, the book discusses the phenomenon of periodic precipitation, which often governs the distribution of crystal in laboratory growth systems. For the first time, computer techniques are brought to bear on the subject, the diffusion equations being solved numerically, in association with the conditions governing precipitations and crystal growth.

Marital Change Across the Transition to Parenthood

Abstract: Recent studies of the transition to parenthood which advance understanding over to earlier, cross sectional and retrospective investigations are examined with regard to what they indicate about how marriages change that occur in marital activities/interactions and sentiments, design issues pertaining to this recent research are considered, specifically the need for and meaning of a childless comparison group. An analysis of studies which employ and do not employ such contrast groups indicates that across the transition household of labor becomes more traditional, couple leisure activities become less frequent, positive interchanges decrease whereas conflict increases, and overall satisfaction with the marriage and feelings of love for the spouse decline, especially in the case of wives. It is observed, however, that these changes are modest in magnitude (at least as currently measured) and probably represent the accentuation of changes that typically take place in marital relationships over time. The need...

Central distribution of subdiaphragmatic vagal branches in the rat.

Abstract: In the rat, the subdiaphragmatic vagus nerves (SDX) have five major branches--the right gastric, the left gastric, the coeliac, the accessory coeliac, and the hepatic Although these branches innervate more than the organs after which they are named, some mediate specific behavioral functions In addition to the SDX trunk, the central stump of each of these branches was incubated in horseradish peroxidase (HRP) for 6 hours in anesthetized rats After processing the vagal ganglia, pons, medulla, and upper cervical spinal cord of each preparation, the sections were examined for both retrogradely and anterogradely transported HRP reaction product When only one nerve had been incubated, retrogradely labeled neurons were confined primarily to the ipsilateral ganglion, medulla, and spinal cord Within the brain, a few labeled neurons occurred within the nucleus ambiguus (NA) and the reticular formation caudal to the NA, but the vast majority appeared in the dorsal motor nucleus of the vagus (DMX) The axons of most labeled neurons in the NA distributed in the gastric branches; those from cells caudal to the NA, probably distributed in the coeliac branch Most labeled DMX cells also distributed with the gastric branches Those on the lateral tip of the right DMX, however, had axons in the coeliac branch; those on the left DMX tip, in the accessory coeliac After incubation of the SDX trunk, anterograde HRP reaction product occurred in the caudomedial nucleus of the solitary tract (NST) just rostral and subjacent to the area postrema (AP) Unlike the retrograde label, anterograde reaction product was bilateral, but always weaker contralaterally Within the SDX distribution, the afferent axons from the gastric branches exhibited one pattern of termination; those from the coeliac, accessory coeliac, and hepatic branches, another The gastric branch distributions began dorsolaterally in the SDX termination zone and continued caudally beneath the AP Immediately subjacent to the AP, gastric branch terminals were never dense and the entire distribution faded at the level of the obex The coeliac and accessory coeliac distributions began dorsomedially within the SDX termination zone and intensified caudally in a thin band immediately subjacent to the AP The densest label was associated with the caudal half of the AP, but the distribution thinned rapidly caudal to the obex The hepatic distribution was similar to that of the coeliac branches but never achieved similar density Physiological and behavioral data correlate with the anatomical picture in that the efferent functions appear to be more densely localized than the afferent functions

The use of budgetary symbols in the political arena: An historically informed field study☆

Abstract: Within accounting, an emerging perspective has held that budgeting is complicit in the creation of a social reality. Seen in such terms, budgetary dialogue is one manner in which societal expectations are expressed, thereby transforming contemporary organizations. Further, it is argued that organizational practice must specifically embody and reproduce these societal expectations in order for the organization to exist. This paper describes a field study directed at assessing the usefulness of such a perspective on budgeting by examining the nature of the budgetary process between a major state university and its state government.

Crystals in Gels and Liesegang Rings

Abstract: Providing the first comprehensive overview of the method of crystal growth in gels, Professor Henisch reviews the field, covering the underlying physics as well as the empirical experience of growth techniques accumulated over the past century. In addition, the book discusses the phenomenon of periodic precipitation, which often governs the distribution of crystal in laboratory growth systems. For the first time, computer techniques are brought to bear on the subject, the diffusion equations being solved numerically, in association with the conditions governing precipitations and crystal growth.