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Showing papers by "University of Georgia published in 2000"


Journal ArticleDOI
TL;DR: The establishment of measurement invariance across groups is a logical prerequisite to conducting substantive cross-group comparisons (e.g., tests of group mean differences, invariance of structura, etc.).
Abstract: The establishment of measurement invariance across groups is a logical prerequisite to conducting substantive cross-group comparisons (e.g., tests of group mean differences, invariance of structura...

6,086 citations


Journal ArticleDOI
TL;DR: It is proposed that the individual traits of playfulness and personal innovativeness are important determinants of cognitive absorption, and operational measures for each dimension of this multi-dimensional construct are developed.
Abstract: Extant explanations of why users behave in particular ways toward information technologies have tended to focus predominantly on instrumental beliefs as drivers of individual usage intentions. Prior work in individual psychology, however, suggests that holistic experiences with technology as captured in constructs such as enjoyment and flow are potentially important explanatory variables in technology acceptance theories. In this paper, we describe a multi-dimensional construct labeled cognitive absorption and defined as a state of deep involvement with software. Cognitive absorption, theorized as being exhibited through the five dimensions of temporal dissociation, focused immersion, heightened enjoyment, control, and curiosity, is posited to be a proximal antecedent of two important beliefs about technology use: perceived usefulness and perceived ease of use. In addition, we propose that the individual traits of playfulness and personal innovativeness are important determinants of cognitive absorption. Based on the conceptual definition of this construct, operational measures for each dimension are developed. Using the World Wide Web as the target technology, scale validation indicates that the operational measures have acceptable psychometric properties and confirmatory factor analysis supports the proposed multi-dimensional structure. Structural equation analysis provides evidence for the theorized nomological net of cognitive absorption. Theoretical and practical implications are offered

4,018 citations


Journal ArticleDOI
21 Jan 2000-Science
TL;DR: These phenomena have two major biological implications: many wildlife species are reservoirs of pathogens that threaten domestic animal and human health; second, wildlife EIDs pose a substantial threat to the conservation of global biodiversity.
Abstract: Emerging infectious diseases (EIDs) of free-living wild animals can be classified into three major groups on the basis of key epizootiological criteria: (i) EIDs associated with “spill-over” from domestic animals to wildlife populations living in proximity; (ii) EIDs related directly to human intervention, via host or parasite translocations; and (iii) EIDs with no overt human or domestic animal involvement. These phenomena have two major biological implications: first, many wildlife species are reservoirs of pathogens that threaten domestic animal and human health; second, wildlife EIDs pose a substantial threat to the conservation of global biodiversity.

3,757 citations


Journal ArticleDOI
TL;DR: Public attitudes about the need for conservation of reptiles are probably linked to concern about amphibian declines and deformities, and counts of “officially” recognized endangered and threatened species are likely to grossly underestimate the actual number of imperiled s pecies.
Abstract: A s a group [reptiles] are nei t h er ‘good ’n or ‘b ad ,’ but ia re intere s ting and unu su a l , a l t h o u gh of m i n or i m port a n ce . If t h ey should all disappe a r, it wo u l d not make mu ch differen ce one way or the other ”( Zim and Smith 1953, p. 9 ) . Fortu n a tely, this op i n i on from the Golden Gu i de Series does not persist tod ay; most people have com e to recogn i ze the va lue of both reptiles and amph i bians as an i n tegral part of n a tu ral eco s ys tems and as heralds of envi ron m ental qu a l i ty (Gibbons and Stangel 1999). In recent ye a rs , as overa ll envi ron m ental aw a reness among the p u blic has incre a s ed , con cerns have come to inclu de intere s t in the eco l ogical state of reptile and amph i bian spec i e s t h em s elves and of t h eir habi t a t s . In c re a s ed aw a reness may s tem from bet ter edu c a ti on abo ut threats to bi od ivers i ty in gen era l , and to reptiles and amph i bians in parti c u l a r, a n d po s s i bly even from an innate attracti on to these taxa ( Kell ert and Wi l s on 1993). From the perspective of many nonscientists, the two vertebrate classes comprising reptiles and amphibians, collectively referred to as the herpetofauna, are interchangeable. For example,the Boy Scout merit badge pamphlet for herpetology was called simply Reptile Study from 1926 to 1993 (Conant 1972, Gibbons 1993), and major zoos (e.g., National Zoo in Washington, DC; Zoo Atlanta; and San Diego Zoo) use only the name “reptile” to refer to the facility that houses both amphibians and reptiles. Thus, public attitudes about the need for conservation of reptiles are probably linked to concern about amphibian declines and deformities (Alford and Richards 1999, Johnson et al. 1999, Sessions et al. 1999), which have been the subject of numerous, well-documented scientific studies. Because amphibians are distributed worldwide, but herpetologists who document amphibian declines are not, it is difficult to accurately assess what portion of amphibian populations are experiencing significant declines or have already disappeared. Furthermore, the means of determining a species’ conservation status is a rigorous and time-intensive process, and therefore counts of “officially” recognized endangered and threatened species are likely to grossly underestimate the actual number of imperiled s pecies (Ta ble 1). The worl dwi de amph i bian decl i n e probl em , as it has come to be known, has garnered significant attention not only among scientists but also in the popular media and in political circles.

1,624 citations


Journal ArticleDOI
TL;DR: In this paper, the interior of the most massive brown dwarfs is shown to develop a conductive core after ~2 Gyr which slows down their cooling, and the authors suggest the possibility of a brown dwarf dearth in J, H, and K color-magnitude diagrams around this temperature.
Abstract: We present evolutionary calculations for very low-mass stars and brown dwarfs based on synthetic spectra and nongray atmosphere models which include dust formation and opacity, i.e., objects with Teff 2800 K. The interior of the most massive brown dwarfs is shown to develop a conductive core after ~2 Gyr which slows down their cooling. Comparison is made in optical and infrared color-magnitude diagrams with recent late-M and L dwarf observations. The saturation in optical colors and the very red near-infrared colors of these objects are well explained by the onset of dust formation in the atmosphere. Comparison of the faintest presently observed L dwarfs with these dusty evolutionary models suggests that dynamical processes such as turbulent diffusion and gravitational settling are taking place near the photosphere. As the effective temperature decreases below Teff ≈ 1300-1400 K, the colors of these objects move to very blue near-infrared colors, a consequence of the ongoing methane absorption in the infrared. We suggest the possibility of a brown dwarf dearth in J, H, and K color-magnitude diagrams around this temperature.

1,446 citations


Journal ArticleDOI
TL;DR: Hutchinson’s niche concept can be modified to incorporate the influences of niche width, habitat availability and dispersal, as well as interspecific competition per se, and a simulation model called NICHE is introduced that embodies many of Hutchinson's original niche concepts and is used to predict patterns of species distribution.
Abstract: Applications of Hutchinson’s n-dimensional niche concept are often focused on the role of interspecific competition in shaping species distribution patterns. In this paper, I discuss a variety of factors, in addition to competition, that influence the observed relationship between species distribution and the availability of suitable habitat. In particular, I show that Hutchinson’s niche concept can be modified to incorporate the influences of niche width, habitat availability and dispersal, as well as interspecific competition per se. I introduce a simulation model called NICHE that embodies many of Hutchinson’s original niche concepts and use this model to predict patterns of species distribution. The model may help to clarify how dispersal, niche size and competition interact, and under what conditions species might be common in unsuitable habitat or absent from suitable habitat. A brief review of the pertinent literature suggests that species are often absent from suitable habitat and present in unsuitable habitat, in ways predicted by theory. However, most tests of niche theory are hampered by inadequate consideration of what does and does not constitute suitable habitat. More conclusive evidence for these predictions will require rigorous determination of habitat suitability under field conditions. I suggest that to do this, ecologists must measure habitat specific demography and quantify how demographic parameters vary in response to temporal and spatial variation in measurable niche dimensions.

1,379 citations


Journal ArticleDOI
TL;DR: The authors highlights key conceptual and empirical advances that have emerged in the past decade, with particular emphasis on interpersonal processes that operate within marriage, including cognition, affect, physiology, behavioral patterning, social support, and violence.
Abstract: Scientific study of marital satisfaction attracted widespread attention in the 1990s from scholars representing diverse orientations and goals. This article highlights key conceptual and empirical advances that have emerged in the past decade, with particular emphasis on (a) interpersonal processes that operate within marriage, including cognition, affect, physiology, behavioral patterning, social support, and violence; (b) the milieus within which marriages operate, including microcontexts (e.g., the presence of children, life stressors and transitions) and macrocontexts (e.g., economic factors, perceived mate availability); and (c) the conceptualization and measurement of marital satisfaction, including 2-dimensional, trajectory-based, and social-cognitive approaches. Notwithstanding the continued need for theoretical progress in understanding the nature and determinants of marital satisfaction, we conclude by calling for more large-scale longitudinal research that links marital processes with sociocultural contexts, for more disconfirmatory than confirmatory research, and for research that directly guides preventive, clinical, and policy-level interventions.

1,170 citations


Journal ArticleDOI
26 May 2000-Science
TL;DR: The degree of aggregation in the distribution of 1768 tree species is examined based on the average density of conspecific trees in circular neighborhoods around each tree, and it is found that nearly every species was more aggregated than a random distribution.
Abstract: Fully mapped tree census plots of large area, 25 to 52 hectares, have now been completed at six different sites in tropical forests, including dry deciduous to wet evergreen forest on two continents. One of the main goals of these plots has been to evaluate spatial patterns in tropical tree populations. Here the degree of aggregation in the distribution of 1768 tree species is examined based on the average density of conspecific trees in circular neighborhoods around each tree. When all individuals larger than 1 centimeter in stem diameter were included, nearly every species was more aggregated than a random distribution. Considering only larger trees (≥ 10 centimeters in diameter), the pattern persisted, with most species being more aggregated than random. Rare species were more aggregated than common species. All six forests were very similar in all the particulars of these results.

1,117 citations


Journal ArticleDOI
TL;DR: In this article, the authors examine potential relationships among categories of personal information, beliefs about direct marketing, situational characteristics, specific privacy concerns, and consumers' direct marketing shopping habits, and offer an assessment of the trade-offs consumers are willing to make when they exchange personal information for shopping benefits.
Abstract: The authors examine potential relationships among categories of personal information, beliefs about direct marketing, situational characteristics, specific privacy concerns, and consumers’ direct marketing shopping habits. Furthermore, the authors offer an assessment of the trade-offs consumers are willing to make when they exchange personal information for shopping benefits. The findings indicate that public policy and self-regulatory efforts to alleviate consumer privacy concerns should provide consumers with more control over the initial gathering and subsequent dissemination of personal information. Such efforts must also consider the type of information sought, because consumer concern and willingness to provide marketers with personal data vary dramatically by information type.

968 citations


Journal ArticleDOI
TL;DR: Because elements are immutable, phytoremediation strategies for radionuclide and heavy metal pollutants focus on hyperaccumulation above-ground, in contrast, organic pollutants can potentially be completely mineralized by plants.

845 citations


Journal ArticleDOI
TL;DR: The Learning Transfer System Inventory (LTSI) as discussed by the authors was developed and administered to 1,616 training participants from a wide range of organizations to measure factors in the system affecting transfer of learning.
Abstract: This study expands on the concept of the learning transfer system and reports on the validation of an instrument to measure factors in the system affecting transfer of learning. The Learning Transfer System Inventory (LTSI) was developed and administered to 1,616 training participants from a wide range of organizations. Exploratory common factor analysis revealed a clean interpretable factor structure of sixteen transfer system constructs. Second-order factor analysis suggested a three-factor higher order structure of climate, job utility, and rewards. The instrument development process, factor structure, and use of the LTSI as a diagnostic tool in organizations are discussed.© 2000 Jossey-Bass, A Publishing Unit of John Wiley & Sons, Inc.

Journal ArticleDOI
TL;DR: In this article, the authors adapt Lambert's methodology to an upper bounded count situation, thereby obtaining a zero-inflated binomial (ZIP) model, and add to the flexibility of these fixed effects models by incorporating random effects so that, e.g., the within-subject correlation and between-subject heterogeneity typical of repeated measures data can be accommodated.
Abstract: Summary. In a 1992 Technometrics paper, Lambert (1992, 34, 1–14) described zero-inflated Poisson (ZIP) regression, a class of models for count data with excess zeros. In a ZIP model, a count response variable is assumed to be distributed as a mixture of a Poisson(λ) distribution and a distribution with point mass of one at zero, with mixing probability p. Both p and λ are allowed to depend on covariates through canonical link generalized linear models. In this paper, we adapt Lambert's methodology to an upper bounded count situation, thereby obtaining a zero-inflated binomial (ZIP) model. In addition, we add to the flexibility of these fixed effects models by incorporating random effects so that, e.g., the within-subject correlation and between-subject heterogeneity typical of repeated measures data can be accommodated. We motivate, develop, and illustrate the methods described here with an example from horticulture, where both upper bounded count (binomial-type) and unbounded count (Poisson-type) data with excess zeros were collected in a repeated measures designed experiment.

Journal ArticleDOI
TL;DR: The authors assesses several major streams in this research over the last two decades, which in some ways refute widely held a priori assumptions about similarities and differences between public and private organizations.
Abstract: Research comparing public and private organizations and examining the publicness of organizations represents a substantial and growing body of empirical evidence, relevant to many international issues in political economy and organization theory such as the privatization of public services. This article assesses several major streams in this research over the last two decades, which in some ways refute widely held a priori assumptions about similarities and differences between public and private organizations but which in some ways support such assumptions. The review covers research on goal complexity and ambiguity, organizational structure, personnel and purchasing processes, and work-related attitudes and values. The research results converge in important ways, but they also present anomalies. For example, in spite of virtually universal agreement among scholars that public organizations have more goal complexity and ambiguity, public managers do not differ from business managers in response to survey questions about such matters. Public managers do not differ from business managers on perceptions about organizational formalization, in spite of a chorus of assertions that government agencies have more red tape and rules than private firms have. Public managers do, however, show very sharp differences in response to questions about constraints under personnel and purchasing rules. The article concludes with an assessment of the credibility of these streams of research through consideration of alternative plausible hypotheses. No enemy of empiricism, Immanuel Kant simply insisted on empiricism's knowing its place. God, freedom, and immortality, Kant asserted, cannot be denied. Each is an a priori category of the mind and, as such, must necessarily be presupposed. One of J-PART 10(2000):2:447-469 modernity's strongest candidates for the a priori, and presumed 447/Journal of Public Administration Research and Theory at U niersity of G ergia on Feruary 9, 2012 http://jpaordjournals.org/ D ow naded rom Comparing Public and Private Organizations exemption from the hurly-burly world of empirical knowledge, is the public organization. Persons on the street and scholars in the academy will lecture at length on the character of public bureaucracies, blithely free of any concern over the need to show evidence for their assertions. Less confident of our own omniscience about this topic, we feel the need to look at evidence. Our article assesses nearly two decades of empirical research comparing public and private organizations with the following questions in mind: (1) What progress has come from the past twenty-five years or so of empirical research on differences between public and private organizations? (2) Why is there so often discrepancy between empirical research and a priori knowledge about public organizations? (3) Why has empirical research been so feckless in the face of well-established, but unproved, assumptions about public organizations? (4) Should this transcendence of the a priori over the empirical matter to anyone other than academic researchers? In this article we cannot resolve all these questions, but we make a start by reviewing several points in this comparative research where findings have converged on a particular conclusion. A second part of the article considers how much confidence we should place in this convergence, in view of various rival explanations that would suggest that the results are wrong. Before going on, we need to clarify what we mean by a priori views about the public-private distinction in organizational and managerial research. Here, a priori refers to untested assertions and foregone conclusions about this distinction. As we will elaborate below, two decades ago the literature on this topic was dominated by observations that had received scant empirical testing and confirmation. While empirical research has accumulated, these a priori views show remarkable staying power even though research has contradicted many of them. A striking aspect of the a priori views, one that made it necessary to test them empirically, is that there were—and still are—two general a priori positions on this topic, and they conflict with each other (see Rainey 1997, chap. 3). Many scholars in economics and political science have taken the position that public bureaucracies differ from private business firms in important ways (e.g., Barton 1980; Dahl and Lindblom 1953; Dixit 1997; Downs 1967). Their observations about the differences have coincided with the negative views of public bureaucracy in the popular culture, that Goodsell (1994) describes, coupled with the perception of business firms as inherently superior in efficiency and effectiveness. Fascinatingly, the people who specialized in analysis of 'Answers: (i) quite a bit, actually; (2) the organizations and management-organizational sociologists and unreliability of conventional wisdom; (3) psychologists, and researchers on business management—usually passive conveying of research; (4) yes! took a diametrically opposing position. They treated such UW-PART, April 2000 at U niersity of G ergia on Feruary 9, 2012 http://jpaordjournals.org/ D ow naded rom Comparing Public and Private Organizations distinctions as public vs. private and for-profit vs. nonprofit as crude stereotypes, taken seriously only by persons poorly educated in the field of organization theory. Prominent scholars denounced these distinctions as harmful and misleading oversimplifications that needed to be exorcised from the literature on organizations and management and replaced with typologies of organizations developed through sound empirical research. Some of the most eminent scholars in management and organization theory took pains to denounce the public-private distinction, or at least to point out that public and private organizations are more similar than they are different. This tradition continues and is manifest, among other ways, in a recent pronunciation by no less a social scientist than Herbert Simon (1995, 283, n. 3). Simon said that public, private, and nonprofit organizations are essentially identical on the dimension that receives more attention than virtually any other in discussions of the unique aspects of public organizations—the capacities of leaders to reward employees. The assumption that leaders in government organizations have less capacity to reward employees than do leaders in business firms, and that government needs to become more like business in this regard, has driven civil service reforms at all levels of government in the United States and in otheT nations. Yet a Nobel Laureate denies that such differences exist. Thus we have a strong a priori position among many economists and political scientists that treats a distinction between public and private organizations as a truism, while many organization theorists have treated this same distinction with contempt. This divergence among different fields complicates but also enhances the analysis of a priori assertions and of convergence in the research. When we refer to convergence of findings at various points in this article, we often are referring to convergence of findings that support one or the other of these two sides. Part of the value of the stream of research that we review is that it shows that both sides of this divergence were right in some ways 'Generalizations like these always involve and m c o m p i e te in other ways. The findings indicate definite coninjustices and oversimplifications them, • ^ .i_ i_ u » *: i -J cselves. Exceptions abound. Among mmy vergence on the point that we have substantial evidence of unporexampies are a typology developed by tant differences between public and private organizations. Yet organization theorists Peter Biau and they also indicate convergence on evidence that some of the freRichard Scott (1962) that included cate^ ^ y asserted differences receive little or no empirical confirgories for business firms and for public . , , , . . . . . . . . .. . . agencies, along with additional categories. m&tion and that the pubhc-pnvate distinction may well mvolve and many other references to public oversimplifications and stereotypes in those cases. Happily, both organizations by organization dworists sides can take pride in being right in certain ways. (Perry and Rainey 1988). The Dahl and Lindblom analysis and the Downs anal, » : « . _ » »i_ • -i •»• ysis are actually much more balanced and W e n e e d however, to continue to sort out the similarities carefully reasoned than the phrasing here and differences, whether or not our results please one side of the might suggest. debate or the other. The analysis of this topic has important 449/J-PART, April 2000 at U niersity of G ergia on Feruary 9, 2012 http://jpaordjournals.org/ D ow naded rom Comparing PubUc and Private Organizations implications for major current theoretical and practical issues, including these: privatization of public services; allocation of functions and tasks among sectors; the nature of the sectors themselves; the dimensions that define the sectors, including their complex overlapping and blurring with the third and nonprofit sectors; administrative reforms and organizational change; and the theoretical and practical analysis of major administrative topics, such as organizational goals, structure, and individual motivation and work attitudes. EMPIRICAL RESULTS COMPARING PUBUC AND PRIVATE ORGANIZATIONS Research that compares public and private organizations and examines the publicness of organizations now represents a substantial body of empirical evidence. Twenty-five years ago, a systematic empirical research base had just begun to accumulate. In one comprehensive review of writings about public and private organizations (Rainey, Backoff, and Levine 1976), less than ten of the nearly one hundred papers and books cited provided propositions based on empirical research. By contrast,

Journal ArticleDOI
TL;DR: Results parallel earlier comparative summaries of allozyme variation in marine, anadromous, and freshwater fishes and probably are attributable in part to differences in evolutionarily effective population sizes typifying species inhabiting these realms.
Abstract: Author(s): DeWoody, JA; Avise, JC | Abstract: From a total of 524 microsatellite loci considered in nearly 40 000 individuals of 78 species, freshwater fish displayed levels of population genetic variation (mean heterozygosity, h=0.46, and mean numbers of alleles per locus, a=7.5) roughly similar to those of non-piscine animals (h=0.58 and a=7.1). In contrast, local population samples of marine fish displayed on average significantly higher heterozygosities (h=0.79) and nearly three times the number of alleles per locus (a=20.6). Anadromous fish were intermediate to marine and freshwater fish (h=0.68 and a=11.3). Results parallel earlier comparative summaries of allozyme variation in marine, anadromous, and freshwater fishes and probably are attributable in part to differences in evolutionarily effective population sizes typifying species inhabiting these realms. (C) 2000 The Fisheries Society of the British Isles.

Journal ArticleDOI
TL;DR: In this paper, the authors studied sequential long-term photochemical and biological degradation of estuarine dissolved organic matter from the Satilla River, an estuary in the southeastern United States that is dominated by vascular plant-derived organic matter.
Abstract: Terrestrially derived dissolved organic matter (DOM) impacts the optical properties of coastal seawater and affects carbon cycling on a global scale. We studied sequential long-term photochemical and biological degradation of estuarine dissolved organic matter from the Satilla River, an estuary in the southeastern United States that is dominated by vascular plant-derived organic matter. During photodegradation, dissolved organic carbon (DOC) loss (amounting to 31% of the initial DOC) was much less extensive than colored dissolved organic matter (CDOM) or fluorescent dissolved organic matter (FDOM) loss (50% and 56% of the initial CDOM and FDOM), and analysis of kinetics suggested a reservoir of DOC that was resistant to photodegradation. In contrast, CDOM photodegradation closely followed first-order kinetics over two half-lives with no indication of a nondegradable component. FDOM loss was slightly biased toward fluorophores considered representative of terrestrial humic substances. Additional changes in optical properties included increases in spectral slope and shifts in fluorescence excitation/ emission maxima that were generally consistent with previous observations from field studies of photobleached DOM. Biological degradation of photobleached DOM was more rapid than that of unbleached material, and this net positive effect was evident even for extensively photodegraded material. Bacterial degradation caused shifts in the opposite direction from photochemical degradation for both spectral slope and excitation/emission maxima and thus dampened but did not eliminate changes in optical properties caused by photobleaching.

Journal ArticleDOI
TL;DR: Policy implementation has been a hot topic in recent years as discussed by the authors, with a resurgence of attention to the subject. But some of the discourse has shifted, the questions have broadened, and the agenda has become complicated.
Abstract: While policy implementation no longer frames the core question of public management and public policy, some scholars have debated appropriate steps for revitalization. And the practical world stands just as much in need now of valid knowledge about policy implementation as ever. Where has all the policy implementation gone? Or at least all the scholarly signs of it? And why? What has the field accomplished? Should a resurgence of attention to the subject be exhorted? And if so, in what directions? This article considers these questions as foci of an assessment of the state of the field, and the argument reaches somewhat unconventional conclusions: There is more here than meets the eye. While modest to moderate progress can be noted on a number of fronts, an initial assessment is likely to understate the extent of work underway on matters quite close to the implementation theme. Research on policy implementation-like questions has partially transmogrified. One has to look, sometimes, in unusual places and be informed by a broader logic of intellectual development to make sense of the relevant scholarship. Policy implementation work, in short, continues to bear relevance for important themes of policy and management. But some of the discourse has shifted, the questions have broadened, and the agenda has become complicated. Research on implementation, under whatever currently fashionable labels, is alive and lively.

Journal ArticleDOI
TL;DR: This review summarizes the currently known components of the telomere/telomerase functional complex, and focuses on how they act in the control of processes occurring at telomeres.
Abstract: ▪ Abstract Telomeres are DNA and protein structures that form complexes protecting the ends of chromosomes. Understanding of the mechanisms maintaining telomeres and insights into their function have advanced considerably in recent years. This review summarizes the currently known components of the telomere/telomerase functional complex, and focuses on how they act in the control of processes occurring at telomeres. These include processes acting on the telomeric DNA and on telomeric proteins. Key among them are DNA replication and elongation of one telomeric DNA strand by telomerase. In some situations, homologous recombination of telomeric and subtelomeric DNA is induced. All these processes act to replenish or restore telomeres. Conversely, degradative processes that shorten telomeric DNA, and nonhomologous end-joining of telomeric DNA, can lead to loss of telomere function and genomic instability. Hence they too must normally be tightly controlled.

Journal ArticleDOI
TL;DR: The F-box is a protein motif of approximately 50 amino acids that functions as a site of protein-protein interaction that links the F- box protein to other components of the SCF complex by binding the core SCF component Skp I.
Abstract: The F-box is a protein motif of approximately 50 amino acids that functions as a site of protein-protein interaction. F-box proteins were first characterized as components of SCF ubiquitin-ligase complexes (named after their main components, Skp I, Cullin, and an F-box protein), in which they bind substrates for ubiquitin-mediated proteolysis. The F-box motif links the F-box protein to other components of the SCF complex by binding the core SCF component Skp I. F-box proteins have more recently been discovered to function in non-SCF protein complexes in a variety of cellular functions. There are 11 F-box proteins in budding yeast, 326 predicted in Caenorhabditis elegans, 22 in Drosophila, and at least 38 in humans. F-box proteins often include additional carboxy-terminal motifs capable of protein-protein interaction; the most common secondary motifs in yeast and human F-box proteins are WD repeats and leucine-rich repeats, both of which have been found to bind phosphorylated substrates to the SCF complex. The majority of F-box proteins have other associated motifs, and the functions of most of these proteins have not yet been defined.

Journal ArticleDOI
TL;DR: In this article, over 800 American teachers responded to an open-ended questionnaire by identifying and describing characteristics of principals that enhanced their classroom instruction and what impacts those characteristics had on them.
Abstract: Few studies have directly examined teachers’ perspectives on principals’ everyday instructional leadership characteristics and the impacts of those characteristics on teachers. In this study, over 800 American teachers responded to an open‐ended questionnaire by identifying and describing characteristics of principals that enhanced their classroom instruction and what impacts those characteristics had on them. The data revealed two themes (and 11 strategies) of effective instructional leadership: talking with teachers to promote reflection and promoting professional growth.

Journal ArticleDOI
TL;DR: For example, the authors of the paper as discussed by the authors presented the results of a study at the Netherlands Institute of Terrestrial Ecology (ZG Heteren) and the University of Utrecht (UTHeteren).
Abstract: Assistant professor in the Department of Biology at Western Washington University, Bellingham, Washington 98225-9160 10: Professor at the Laboratoire d'Ecologie de Sols Tropicaux, ORSTOM/Universite Paris VI, 32 Avenue Henri Varagnat, 93143 Bondy, France 11: Senior scientist at the Centre for Terrestrial Ecology, Netherlands Institute of Ecology, 6666 ZG Heteren, Netherlands Utrecht, Netherlands 12: Professor at the Department of Environmental Studies, University of Utrecht, Utrecht, Netherlands 13: Professor at the Institute of Soil Biology, Academy of Sciences of the Czech Republic, Na sadkach 7, 370 05 Ceske Budejovice, Czech Republic 14: Professor at the Department of Environmental Science, Policy,and Management, University of California, Berkeley, California 94720-3110 15: Professor at the Center for Microbial Ecology, Michigan State University, 540 Plant and Soil Science Building, East Lansing, Michigan 48824-1325 16: Professor at the Department of Animal Ecology, Justus Liebig University of Giessen, Heinrich-Buff-Ring 26-32 (IFZ), D-35392 Giessen, Germany 2: Professor at the Queen Mary and Westfield College, School of Biological Sciences, University of London, London E1 4NS, United Kingdom 3: Research professor and the director of the Centre for Agri-Environmental Research, Department of Agriculture, University of Reading, Earley Gate, Reading RG6 6AT, United Kingdom 4: Professor of Soil Biology and Biological Soil Quality and director of the Department of Environmental Sciences, Wageningen University, 6700 EC Wageningen, Netherlands 5: Professor at the Centre for Biodiversity and Bioresources, School of Biological Sciences, Macquarie University, Sydney, New South Wales 2109, Australia 6: Chair, SCOPE Committee on Soil and Sediment Biodiversity and Ecosystem Functioning, and professor and director, Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, Colorado 80523 7: Scientist at Landcare Research, Lincoln, New Zealand 8: Research professor in the Institute of Ecology at the University of Georgia, 102 Ecology Annex, Athens, Georgia 30602-2360 9: Professor at the Department of Soil Science and Agricultural Engineering, University of Zimbabwe, Mount Pleasant, Harare, Zimbabwe

Journal ArticleDOI
TL;DR: In this paper, the authors argue that wages are a better measure of labor market conditions than the unemployment rate, and that economic factors are more important for property crime than violent crime.
Abstract: The relationship between crime and labor market conditions is typically studied by looking at the unemployment rate. In contrast, this paper argues that wages are a better measure of labor market conditions than the unemployment rate. As the wages of those most likely to commit crime (unskilled men) have been falling in the past few decades, we examine the impact of this trend on the crime rate giving special attention to issues of endogeneity. Wages are found to be a significant determinant of crime and more important than the unemployment rate. As theory would predict, economic factors are more important for property crime than violent crime. These results are robust to various measures of wages, two regression strategies, the inclusion of deterrence variables, and controls for simultaneity.

Journal ArticleDOI
TL;DR: Several measures of effect size that might be used in group comparison studies involving univariate and/or multivariate models are discussed.

Journal ArticleDOI
TL;DR: The architecture, design and implementation of the OBSERVER system is described, which considers the use of concepts from pre-existing real world domain ontologies for describing the content of the underlying data repositories.
Abstract: There has been an explosion in the types, availability and volume of data accessible in an information system, thanks to the World Wide Web (the Web) and related inter-networking technologies. In this environment, there is a critical need to replace or complement earlier database integration approaches and current browsing and keyword-based techniques with concept-based approaches. Ontologies are increasingly becoming accepted as an important part of any concept or semantics based solution, and there is increasing realization that any viable solution will need to support multiple ontologies that may be independently developed and managed. In particular, we consider the use of concepts from pre-existing real world domain ontologies for describing the content of the underlying data repositories. The most challenging issue in this approach is that of vocabulary sharing, which involves dealing with the use of different terms or concepts to describe similar information. In this paper, we describe the architecture, design and implementation of the OBSERVER system. Brokering across the domain ontologies is enabled by representing and utilizing interontology relationships such as (but not limited to) synonyms, hyponyms and hypernyms across terms in different ontologies. User queries are rewritten by using these relationships to obtain translations across ontologies. Well established metrics like precision and recall based on the extensions underlying the concepts are used to estimate the loss of information, if any.

Journal ArticleDOI
TL;DR: The authors argue that the interview site itself embodies and constitutes multiple scales of spatial relations and meaning, which construct the power and positionality of participants in relation to the people, places, and interactions discussed in the interview.
Abstract: For qualitative researchers, selecting appropriate sites in which to conduct interviews may seem to be a relatively simple research design issue. In fact it is a complicated decision with wide-reaching implications. In this paper, we argue that the interview site itself embodies and constitutes multiple scales of spatial relations and meaning, which construct the power and positionality of participants in relation to the people, places, and interactions discussed in the interview. We illustrate how observation and analysis of interview sites can offer new insights with respect to research questions, help researchers understand and interpret interview material, and highlight particular ethical considerations that researchers need to address.

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TL;DR: In this paper, the authors compare two methods for the calculation of efficiency; namely Stochastic Frontier Analysis (SFA) and Data Envelopment Analysis (DEA), and reveal the strengths and weaknesses for estimating environmental efficiency of the methods applied.

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TL;DR: In a recent article as discussed by the authors, the authors argued that elephants and public organizations have something in common and proposed a theory of effective public organizations and urge the research community to test this theory empirically.
Abstract: 'In a recent article published in this journal, the authors argued that elephants and public organizations have something in common. Both are saddled with inaccurate stereotypes. Elephants are believed to be slow and insensitive creatures, when in fact they can run very fast and are very sensitive. Similarly, public organizations are believed to be low-performing and unresponsive, when in fact many public organizations perform very well and are models of responsiveness. After making (he crucial point that some public organizations are doing a good job, the authors propose a theory of effective public organizations and urge the research community to test this theory empirically.

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TL;DR: There were no differences between adolescents reared in conventional or nonconventional families in the distribution of adolescent attachment security, the experience of negative life events, or the continuity of attachment from infancy through adolescence.
Abstract: This study reports relations between infant Ainsworth Strange Situation classifications, negative life events, and Adolescent Attachment Interview classifications. Overall, the stability of secure versus insecure classifications was 77%, and infant attachment classification was a significant predictor of adolescent attachment classification. Chi-square analyses indicate that negative life events are significantly related to change in attachment classification. The sample (n = 30) is drawn from the Family Lifestyles Project (FLS), an ongoing longitudinal study of children's development within the context of nonconventional family lifestyles. The distribution of family lifestyles within this study, unlike those in the full FLS sample, represent a higher proportion of conventional two-parent families (40%). There were no differences between adolescents reared in conventional or nonconventional families in the distribution of adolescent attachment security, the experience of negative life events, or the continuity of attachment from infancy through adolescence.


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TL;DR: The ratio of the proton's elastic electromagnetic form factors, G(E(p))/G(M(p)), was obtained by measuring P(t) and P(l), the transverse and the longitudinal recoil proton polarization, respectively, indicating for the first time a definite difference in the spatial distribution of charge and magnetization currents in the Proton.
Abstract: The ratio of the proton's elastic electromagnetic form factors was obtained by measuring the transverse and longitudinal polarizations of recoiling protons from the elastic scattering of polarized electrons with unpolarized protons. The ratio of the electric to magnetic form factor is proportional to the ratio of the transverse to longitudinal recoil polarizations. The ratio was measured over a range of four-momentum transfer squared between 0.5 and 3.5 GeV-squared. Simultaneous measurement of transverse and longitudinal polarizations in a polarimeter provides good control of the systematic uncertainty. The results for the ratio of the proton's electric to magnetic form factors show a systematic decrease with increasing four momentum squared, indicating for the first time a marked difference in the spatial distribution of charge and magnetization currents in the proton.

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TL;DR: The results show that corals from all depths exhibited bleaching every year, regardless of whether they appeared white, tan, or mottled to the human eye, suggesting that all tropical reef-building corals, world-wide, exhibit similar predictable cycles in their tissue biomass and symbiotic algae.
Abstract: Tissue biomass (ash-free dry weight) and symbiotic dinoflagellates (density, chlorophyll a cell 21 or cm 22 of coral surface area) of five species of reef-building corals were monitored seasonally for up to 4 yr at three different depths in the Bahamas. The lowest values of all tissue biomass and algal symbiont parameters occurred during the late summer‐fall sample periods. In contrast, the highest densities and pigment content of symbionts usually occurred during the winter, whereas tissue biomass peaked most often in the spring, the time lag implying a functional relationship between these variables. Corals living in shallow water often (but not always) had higher levels of all parameters measured compared to deeper corals, except chlorophyll a content, which usually displayed the opposite trend. The results show that corals from all depths exhibited bleaching (loss of symbiotic dinoflagellates and/or their pigments) every year, regardless of whether they appeared white, tan, or mottled to the human eye. We speculate that these patterns are driven by seasonal changes in light and temperature on algal and animal physiology. Furthermore, we hypothesize that all tropical reef-building corals, world-wide, exhibit similar predictable cycles in their tissue biomass and symbiotic algae.