Showing papers by "University of Connecticut published in 2000"

Democracy and Development: Political Institutions and Well-Being in the World, 1950–1990

Abstract: Introduction 1. Democracies and dictatorships 2. Dynamic of political regimes 3. Political regimes and economic growth 4. Political instability and economic growth 5. Political regimes and population Conclusion.

The Logic of Violence in Civil War

Abstract: Introduction 1. Concepts and definitions 2. Pathologies 3. Barbarism 4. A theory of irregular war I: collaboration 5. A theory of irregular war II: control 6. The logic of indiscriminate violence 7. A theory of selective violence 8. Empirics I: comparative evidence 9. Empirics II: microcomparative evidence 10. Intimacy 11. Cleavage and agency Conclusion.

Interleukin-7 mediates the homeostasis of naïve and memory CD8 T cells in vivo.

Abstract: The naive and memory T lymphocyte pools are maintained through poorly understood homeostatic mechanisms that may include signaling via cytokine receptors. We show that interleukin-7 (IL-7) plays multiple roles in regulating homeostasis of CD8+ T cells. We found that IL-7 was required for homeostatic expansion of naive CD8+ and CD4+ T cells in lymphopenic hosts and for CD8+ T cell survival in normal hosts. In contrast, IL-7 was not necessary for growth of CD8+ T cells in response to a virus infection but was critical for generating T cell memory. Up-regulation of Bcl-2 in the absence of IL-7 signaling was impaired after activation in vivo. Homeostatic proliferation of memory cells was also partially dependent on IL-7. These results point to IL-7 as a pivotal cytokine in T cell homeostasis.

Strategizing Throughout the Organization: Managing Role Conflict in Strategic Renewal

Abstract: Strategic renewal consists of three subprocesses (competence definition, deployment, and modification). Within each subprocess, the roles of top-, middle- and operating-level managers differ in their time horizon, information requirements, and core values. Dissensus in managers' perceptions about the need for change creates strategic role conflicts within individual managers and between managerial roles. In this article we explain when and where strategic role conflict occurs and how organizational controls may be used to alleviate it.

Necrotic but not apoptotic cell death releases heat shock proteins, which deliver a partial maturation signal to dendritic cells and activate the NF-κB pathway

Abstract: Dendritic cells (DC) are key components of innate and adaptive immune responses. The identity of endogenous signals that activate DC is a crucial and unresolved question. We report here that heat shock proteins (HSP), the most abundant and conserved mammalian molecules, constitute such an internal signal. Necrotic but not apoptotic cell death leads to release of HSP gp96, calreticulin, hsp90 and hsp70. HSP stimulate macrophages to secrete cytokines, and induce expression of antigen-presenting and co-stimulatory molecules on the DC. The HSP gp96 and hsp70 act differentially, and each induces some but not all molecules. HSP interact with these antigen-presenting cells through the highly conserved NF-kappa B pathway. As HSP are intracellular, abundant and soluble, their presence in the extra-cellular milieu and the consequent activation of antigen-presenting cells (APC) constitutes an excellent mechanism for response to cell death. As HSP are conserved from bacteria to mammals, the ability of HSP to activate APC provides a unified mechanism for response to internal and external stimuli.

Art and Agency: An Anthropological Theory.

Abstract: Art and Agency: An Anthropological Theory. Alfred Gell. New York: Oxford University Press, 1998. 271 pp.

Handbook of early childhood intervention

Abstract: Foreword E. F. Zigler Preface Part 1. Introduction: Part II. Concepts of Developmental Vulnerability: Part III. Theoretical Bases of Early Intervention: Part IV. Approaches to Assessment: Part V. Models of Service Delivery: Part VI. Research Perspectives and Findings: Part VII. Policy Issues and Programmatic Directions.

Fast quantum gates for neutral atoms

Abstract: We propose several schemes for implementing a fast two-qubit quantum gate for neutral atoms with the gate operation time much faster than the time scales associated with the external motion of the atoms in the trapping potential. In our example, the large interaction energy required to perform fast gate operations is provided by the dipole-dipole interaction of atoms excited to low-lying Rydberg states in constant electric fields. A detailed analysis of imperfections of the gate operation is given.

Edg-1, the G protein–coupled receptor for sphingosine-1-phosphate, is essential for vascular maturation

Abstract: Sphingolipid signaling pathways have been implicated in many critical cellular events. Sphingosine-1-phosphate (SPP), a sphingolipid metabolite found in high concentrations in platelets and blood, stimulates members of the endothelial differentiation gene (Edg) family of G protein-coupled receptors and triggers diverse effects, including cell growth, survival, migration, and morphogenesis. To determine the in vivo functions of the SPP/Edg signaling pathway, we disrupted the Edg1 gene in mice. Edg1(-/-) mice exhibited embryonic hemorrhage leading to intrauterine death between E12.5 and E14.5. Vasculogenesis and angiogenesis appeared normal in the mutant embryos. However, vascular maturation was incomplete due to a deficiency of vascular smooth muscle cells/pericytes. We also show that Edg-1 mediates an SPP-induced migration response that is defective in mutant cells due to an inability to activate the small GTPase, Rac. Our data reveal Edg-1 to be the first G protein-coupled receptor required for blood vessel formation and show that sphingolipid signaling is essential during mammalian development.

Urinary and sexual function after radical prostatectomy for clinically localized prostate cancer : The Prostate Cancer Outcomes Study

Abstract: ContextPatients with prostate cancer and their physicians need knowledge of treatment options and their potential complications, but limited data on complications are available in unselected population-based cohorts of patients.ObjectiveTo measure changes in urinary and sexual function in men who have undergone radical prostatectomy for clinically localized prostate cancer.DesignThe Prostate Cancer Outcomes Study, a population-based longitudinal cohort study with up to 24 months of follow-up.SettingPopulation-based cancer registries in 6 geographic regions of the United States.ParticipantsA total of 1291 black, white, and Hispanic men aged 39 to 79 years who were diagnosed as having primary prostate cancer between October 1, 1994, and October 31, 1995, and who underwent radical prostatectomy within 6 months of diagnosis for clinically localized disease.Main Outcome MeasuresDistribution of and change in urinary and sexual function measures reported by patients at baseline and 6, 12, and 24 months after diagnosis.ResultsAt 18 or more months following radical prostatectomy, 8.4% of men were incontinent and 59.9% were impotent. Among men who were potent before surgery, the proportion of men reporting impotence at 18 or more months after surgery varied according to whether the procedure was nerve sparing (65.6% of non–nerve-sparing, 58.6% of unilateral, and 56.0% of bilateral nerve–sparing). At 18 or more months after surgery, 41.9% reported that their sexual performance was a moderate-to-large problem. Both sexual and urinary function varied by age (39.0% of men aged <60 years vs 15.3%-21.7% of older men were potent at ≥18 months [P<.001]; 13.8% of men aged 75-79 years vs 0.7%-3.6% of younger men experienced the highest level of incontinence at ≥18 months [P = .03]), and sexual function also varied by race (38.4% of black men reported firm erections at ≥18 months vs 25.9% of Hispanic and 21.3% of white men; P = .001).ConclusionsOur study suggests that radical prostatectomy is associated with significant erectile dysfunction and some decline in urinary function. These results may be particularly helpful to community-based physicians and their patients with prostate cancer who face difficult treatment decisions.

The mid-domain effect: geometric constraints on the geography of species richness.

Abstract: Geographic patterns of species richness are influenced by many factors, but the role of shared physiographical and physiological boundaries in relation to range-size distributions has been surprisingly neglected, in spite of the fact that such geometric constraints lead to mid-domain richness peaks even without environmental gradients (the mid-domain effect). Relying on null models, several recent studies have begun to quantify this problem using simulated and empirical data. This approach promises to transform how we perceive geographic variation in diversity, including the long unresolved latitudinal gradient in species richness. The question is not whether geometry affects such patterns, but by how much.

National athletic trainers' association position statement: fluid replacement for athletes.

Abstract: Objective: To present recommendations to optimize the fluid-replacement practices of athletes. Background: Dehydration can compromise athletic performance and increase the risk of exertional heat injury. Athletes do not voluntarily drink sufficient water to prevent dehydration during physical activity. Drinking behavior can be modified by education, increasing accessibility, and optimizing palatability. However, excessive overdrinking should be avoided because it can also compromise physical performance and health. We provide practical recommendations regarding fluid replacement for athletes. Recommendations: Educate athletes regarding the risks of dehydration and overhydration on health and physical performance. Work with individual athletes to develop fluid-replacement practices that optimize hydration status before, during, and after competition.

Technology Adaptation: The Case of a Computer-Supported Inter-Organizational Virtual Team

Abstract: The adaptation process for new technology is not yet well understood. This study analyzes how an inter-organizational virtual team, tasked with creating a highly innovative product over a 10 month period, adapted the use of a collaborative technology and successfully achieved its challenging objectives. The study of such a virtual team is especially useful for extending our understanding of the adaptation process as virtual teams have more malleable structures than typical organizational units and controlled group experiments. Data were obtained from observations of weekly virtual meetings, electronic log files, interviews, and weekly questionnaires administered to team members. We found that the team initially experienced significant misalignments among the pre-existing organizational environment, group, and technology structures. To resolve these misalignments, the team modified the organizational environment and group structures, leaving the technology structure intact. However, as the team proceeded, a series of events unfolded that caused the team to re-evaluate and further modify its structures. This final set of modifications involved reverting back to the pre-existing organizational environment, while new technology and group structures emerged as different from both the pre-existing and the initial ones. A new model of the adaptation process - one that integrates these findings and those of several previous models - is proposed.

The relationship of gender to pain, pain behavior, and disability in osteoarthritis patients: the role of catastrophizing.

Abstract: One hundred and sixty-eight patients with osteoarthritis (OA) of the knees participated in this study. Of the participants, 72 were men and 96 were women. All participants completed the Arthritis Impact Measurement Scales (AIMS), underwent a 10 min standardized observation session to assess their pain behavior, and completed the Catastrophizing Scale of the Coping Strategies Questionnaire (CSQ) and the Depression Scale of the Symptom Checklist 90 Revised (SCL-90R). The study found that there were significant differences in pain, pain behavior, and physical disability in men and women having OA. Women had significantly higher levels of pain and physical disability, and exhibited more pain behavior during an observation session than men. Further analyses revealed that catastrophizing mediated the relationship between gender and pain-related outcomes. Once catastrophizing was entered into the analyses, the previously significant effects of gender were no longer found. Interestingly, catastrophizing still mediated the gender-pain relationship even after controlling for depression. These findings underscore the importance of both gender and catastrophizing in understanding the OA pain experience and may have important implications for pain assessment and treatment.

CD91: a receptor for heat shock protein gp96.

Abstract: Antigen presenting cells (APCs) can take up exogenous antigenic peptides chaperoned by heat shock protein gp96 and re-present them through the endogenous pathway on their major histocompatibility class I molecules. The high efficiency of this process has been attributed previously to a receptor for gp96 on APCs. The CD91 molecule (also called alpha 2-macroglobulin receptor or the low density lipoprotein-related protein) is shown here to be a cell surface receptor for the heat shock protein gp96. CD91 binds gp96 directly, rather than through another ligand for CD91. The previously known CD91 ligand, alpha 2-macroglobulin, inhibits re-presentation of gp96-chaperoned antigenic peptides by macrophages, as do antibodies to CD91. As gp96 is exclusively intracellular and is released as a result of necrotic but not apoptotic cell death, we propose that CD91 acts as a sensor for necrotic cell death.

The role of microbes in accretion, lamination and early lithification of modern marine stromatolites

Abstract: For three billion years, before the Cambrian diversification of life, laminated carbonate build-ups called stromatolites were widespread in shallow marine seas. These ancient structures are generally thought to be microbial in origin and potentially preserve evidence of the Earth's earliest biosphere. Despite their evolutionary significance, little is known about stromatolite formation, especially the relative roles of microbial and environmental factors in stromatolite accretion. Here we show that growth of modern marine stromatolites represents a dynamic balance between sedimentation and intermittent lithification of cyanobacterial mats. Periods of rapid sediment accretion, during which stromatolite surfaces are dominated by pioneer communities of gliding filamentous cyanobacteria, alternate with hiatal intervals. These discontinuities in sedimentation are characterized by development of surface films of exopolymer and subsequent heterotrophic bacterial decomposition, forming thin crusts of microcrystalline carbonate. During prolonged hiatal periods, climax communities develop, which include endolithic coccoid cyanobacteria. These coccoids modify the sediment, forming thicker lithified laminae. Preservation of lithified layers at depth creates millimetre-scale lamination. This simple model of modern marine stromatolite growth may be applicable to ancient stromatolites.

NG2-positive oligodendrocyte progenitor cells in adult human brain and multiple sclerosis lesions.

Abstract: Multiple sclerosis (MS) is characterized by multifocal loss of myelin, oligodendrocytes, and axons. Potential MS therapies include enhancement of remyelination by transplantation or manipulation of endogenous oligodendrocyte progenitor cells. Characteristics of endogenous oligodendrocyte progenitors in normal human brain and in MS lesions have not been studied extensively. This report describes the distribution of cells in sections from normal adult human brain and MS lesions by using antibodies directed against NG2, an integral membrane chondroitin sulfate proteoglycan expressed by oligodendrocyte progenitor cells. Stellate-shaped NG2-positive cells were detected in the white and gray matter of normal adult human brain and appeared as abundant as, but distinct from, astrocytes, oligodendrocytes, and microglia. Stellate-shaped or elongated NG2-positive cells also were detected in chronic MS lesions. A subpopulation of the elongated NG2-positive cells expressed the putative apoptotic signaling molecule p75(NTR). TUNEL-positive cells in three active, nine chronic active, and four chronic inactive lesions, however, were p75(NTR)-negative. These studies identify cells with phenotypic markers of endogenous oligodendrocyte progenitors in the mature human CNS and suggest that functional subpopulations of NG2-positive cells exist in MS lesions. Endogenous oligodendrocyte progenitor cells may represent a viable target for future therapies intended to enhance remyelination in MS patients.

Functional neuroimaging studies of reading and reading disability (developmental dyslexia)

Abstract: Converging evidence from a number of neuroimaging studies, including our own, suggest that fluent word identification in reading is related to the functional integrity of two consolidated left hemisphere (LH) posterior systems: a dorsal (temporo-parietal) circuit and a ventral (occipito-temporal) circuit. This posterior system is functionally disrupted in developmental dyslexia. Reading disabled readers, relative to nonimpaired readers, demonstrate heightened reliance on both inferior frontal and right hemisphere posterior regions, presumably in compensation for the LH posterior difficulties. We propose a neurobiological account suggesting that for normally developing readers the dorsal circuit predominates at first, and is associated with analytic processing necessary for learning to integrate orthographic features with phonological and lexical-semantic features of printed words. The ventral circuit constitutes a fast, late-developing, word identification system which underlies fluent word recognition in skilled readers.

The underachievement of gifted students: What do we know and where do we go?

Abstract: The process of defining underachievement, identifying underachieving gifted students, and explaining the reasons for this underachievement continues to stir controversy among practitioners, researchers, and clinicians. Despite this interest, the underachievement of gifted students remains an enigma. This article reviews and analyzes three decades of research on the underachievement of gifted students in an attempt to clarify the present state of research. The problems inherent in defining and identifing underachieving gifted students are given special attention. The authors also include suggestions for those interested in pursuing potentially promising new lines of research and inquiry in this area.

Theoretical Approaches to Individual-Level Change in HIV Risk Behavior

Abstract: Over the course of the human immunodeficiency virus (HIV) epidemic, large numbers of HIV prevention interventions have been implemented in a broad array of settings. Unfortunately, there typically has been an enormous gap between what is known about effective HIV prevention interventions and HIV prevention practice as typically implemented.1 To date, the vast majority of interventions targeting groups that practice high-risk behavior have been enacted by the public health sector and are government-funded projects. Generally, these are either implemented directly by state or provincial health departments, or funded by them and administered by community-based organizations (CBOs). All too often, neither behavioral scientists nor well-tested theories of behavior change are incorporated into the intervention design process,2,3 and rigorous evaluations of the efficacy of these programs are rare. A large number of additional HIV prevention interventions have been undertaken by the public schools,4 and in many jurisdictions there are laws mandating that HIV education be provided but without stipulations concerning how this should be done. Primary and secondary educational institutions generally have fielded extremely weak, atheoretical interventions designed not to offend the religious right wing, with content that is highly unlikely to effectively change HIV risk behavior.4 Until recently, of the entire “portfolio” of HIV prevention interventions that have been implemented, most have focused primarily —and in many cases solely—on providing information about HIV. Such information consistently has been shown to be unrelated to HIV risk behavior change.5–8

Nutrition in bone health revisited: a story beyond calcium

Abstract: Osteoporosis is a complex, multi-factorial condition characterized by reduced bone mass and impaired micro-architectural structure, leading to an increased susceptibility to fractures. Although most of the bone strength (including bone mass and quality) is genetically determined, many other factors (nutritional, environmental and life-style) also influence bone. Nutrition is important modifiable factor in the development and maintenance of bone mass and the prevention and treatment of osteoporosis. Approximately 80-90% of bone mineral content is comprised of calcium and phosphorus. Other dietary components, such as protein, magnesium, zinc, copper, iron, fluoride, vitamins D, A, C, and K are required for normal bone metabolism, while other ingested compounds not usually categorized as nutrients (e.g. caffeine, alcohol, phytoestrogens) may also impact bone health. Unraveling the interaction between different factors; nutritional, environmental, life style, and heredity help us to understand the complexity of the development of osteoporosis and subsequent fractures. This paper reviews the role of dietary components on bone health throughout different stages of life. Each nutrient is discussed separately, however the fact that many nutrients are co-dependent and simultaneously interact with genetic and environmental factors should not be neglected. The complexity of the interactions is probably the reason why there are controversial or inconsistent findings regarding the contribution of a single or a group of nutrients in bone health.

Health outcomes after prostatectomy or radiotherapy for prostate cancer: results from the Prostate Cancer Outcomes Study.

Abstract: Background: Radical prostatectomy and external beam radiotherapy are the two major therapeutic options for treating clinically localized prostate cancer. Because survival is often favorable regardless of therapy, treatment decisions may depend on other therapy-specific health outcomes. In this study, we compared the effects of two treatments on urinary, bowel, and sexual functions and on general healthrelated quality-of-life outcomes over a 2-year period following initial treatment. Methods: A diverse cohort of patients aged 55–74 years who were newly diagnosed with clinically localized prostate cancer and received either radical prostatectomy (n = 1156) or external beam radiotherapy (n = 435) were included in this study. A propensity score was used to balance the two treatment groups because they differed in some baseline characteristics. This score was used in multivariable cross-sectional and longitudinal regression analyses comparing the treatment groups. All statistical tests were two-sided. Results: Almost 2 years after treatment, men receiving radical prostatectomy were more likely than men receiving radiotherapy to be incontinent (9.6% versus 3.5%; P<.001) and to have higher rates of impotence (79.6% versus 61.5%; P<.001), although large, statistically significant declines in sexual function were observed in both treatment groups. In contrast, men receiving radiotherapy reported greater declines in bowel function than did men receiving radical prostatectomy. All of these differences remained after adjustments for propensity score. The treatment groups were similar in terms of general health-related quality of life. Conclusions: There are important differences in urinary, bowel, and sexual functions over 2 years after different treatments for clinically localized prostate cancer. In contrast to previous reports, these outcome differences reflect treatment delivered to a heterogeneous group of patients in diverse health care settings. These results provide comprehensive and representative information about long-term treatment complications to help guide and inform patients and clinicians about prostate cancer treatment decisions. [J Natl Cancer Inst 2000;92:1582–92]

The nuclear receptor PPAR gamma and immunoregulation: PPAR gamma mediates inhibition of helper T cell responses.

Abstract: The peroxisome proliferator-activated receptors (PPARs) are a family of transcription factors belonging to the nuclear receptor superfamily Until recently, the genes regulated by PPARs were those believed to be predominantly associated with lipid metabolism Recently, an immunomodulatory role for PPAR gamma has been described in cells critical to the innate immune system, the monocyte/macrophage In addition, evidence for an antiinflammatory role of the PPAR gamma ligand, 15-deoxy-Delta 12,14-PGJ2 (15d-PGJ2) has been found In the present studies, we demonstrate, for the first time, that murine helper T cell clones and freshly isolated splenocytes express PPAR gamma 1 The PPAR gamma expressed is of functional significance in that two ligands for PPAR gamma, 15d-PGJ2 and a thiazolidinedione, ciglitazone, mediate significant inhibition of proliferative responses of both the T cell clones and the freshly isolated splenocytes This inhibition is mediated directly at the level of the T cell and not at the level of the macrophage/APC Finally, we demonstrate that the two ligands for PPAR gamma mediate inhibition of IL-2 secretion by the T cell clones while not inhibiting IL-2-induced proliferation of such clones The demonstration of the expression and function of PPAR gamma in T cells reveals a new level of immunoregulatory control for PPARs and significantly increases the role and importance of PPAR gamma in immunoregulation

Securing information by use of digital holography.

Abstract: An information security method that uses a digital holographic technique is presented. An encrypted image is stored as a digital hologram. The decryption key is also stored as a digital hologram. The encrypted image can be electrically decrypted by use of the digital hologram of the key. This security technique provides secure storage and data transmission. Experimental results are presented to demonstrate the proposed method.

Disruption of the fibroblast growth factor-2 gene results in decreased bone mass and bone formation.

Abstract: Basic fibroblast growth factor (FGF-2), an important modulator of cartilage and bone growth and differentiation, is expressed and regulated in osteoblastic cells. To investigate the role of FGF-2 in bone, we examined mice with a disruption of the Fgf2 gene. Measurement of trabecular bone architecture of the femoral metaphysis of Fgf2+/+ and Fgf2–/– adult mice by micro-CT revealed that the platelike trabecular structures were markedly reduced and many of the connecting rods of trabecular bone were lost in the Fgf2–/– mice. Dynamic histomorphometry confirmed a significant decrease in trabecular bone volume, mineral apposition, and bone formation rates. In addition, there was a profound decreased mineralization of bone marrow stromal cultures from Fgf2–/– mice. This study provides strong evidence that FGF-2 helps determine bone mass as well as bone formation.

Media bias in presidential elections: a meta-analysis

Abstract: A meta-analysis considered 59 quantitative studies containing data concerned with partisan media bias in presidential election campaigns since 1948. Types of bias considered were gatekeeping bias, which is the preference for selecting stories from one party or the other; coverage bias, which considers the relative amounts of coverage each party receives; and statement bias, which focuses on the favorability of coverage toward one party or the other. On the whole, no significant biases were found for the newspaper industry. Biases in newsmagazines were virtually zero as well. However, meta-analysis of studies of television network news showed small, measurable, but probably insubstantial coverage and statement biases.