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Showing papers by "University of Kentucky published in 2000"


Book ChapterDOI
01 Jan 2000
TL;DR: In this article, confirmatory factor analysis (CFA) is used to identify and explore hypothetical constructs as manifest in fallible indicators, where factors are influences that are not directly measured, but account for commonality among a set of measurements.
Abstract: Publisher Summary Confirmatory factor analysis (CFA) is a statistical strategy specifically designed to identify and explore hypothetical constructs as manifest in fallible indicators. The allure of CFA over other approaches to the study of hypothetical constructs is the capacity for testing detailed hypotheses in a deductive mode. Moreover, CFA models can be incorporated directly into general structural equation modeling (SEM) that includes directional relations among hypothetical constructs. It is noted that the central concern of CFA is modeling factors, sometimes referred to as latent variables. Factors are influences that are not directly measured, but account for commonality among a set of measurements. Recent developments in technical aspects of estimation and testing coupled with widely accessible and user-friendly software have rendered CFA more popular and appealing than ever. However, with the increased accessibility of CFA comes a responsibility to understand the conditions under which CFA is appropriately applied and the factors relevant to interpretation of CFA results.

2,055 citations


Journal ArticleDOI
01 Oct 2000
TL;DR: In this article, the authors investigated TAM for work-related tasks with the World Wide Web as the application and found that ease of understanding and ease of finding predict ease of use, and information quality predicts usefulness for revisited sites.
Abstract: The technology acceptance model (TAM) proposes that ease of use and usefulness predict applications usage. The current research investigated TAM for work-related tasks with the World Wide Web as the application. One hundred and sixty-three subjects responded to an e-mail survey about a Web site they access often in their jobs. The results support TAM. They also demonstrate that (1) ease of understanding and ease of finding predict ease of use, and that (2) information quality predicts usefulness for revisited sites. In effect, the investigation applies TAM to help Web researchers, developers, and managers understand antecedents to users' decisions to revisit sites relevant to their jobs.

1,362 citations


Journal ArticleDOI
TL;DR: The Mucorales are associated with angioinvasive disease, often leading to thrombosis, infarction of involved tissues, and tissue destruction mediated by a number of fungal proteases, lipases, and mycotoxins.
Abstract: The Zygomycetes represent relatively uncommon isolates in the clinical laboratory, reflecting either environmental contaminants or, less commonly, a clinical disease called zygomycosis. There are two orders of Zygomycetes containing organisms that cause human disease, the Mucorales and the Entomophthorales. The majority of human illness is caused by the Mucorales. While disease is most commonly linked to Rhizopus spp., other organisms are also associated with human infection, including Mucor, Rhizomucor, Absidia, Apophysomyces, Saksenaea, Cunninghamella, Cokeromyces, and Syncephalastrum spp. Although Mortierella spp. do cause disease in animals, there is no longer sufficient evidence to suggest that they are true human pathogens. The spores from these molds are transmitted by inhalation, via a variety of percutaneous routes, or by ingestion of spores. Human zygomycosis caused by the Mucorales generally occurs in immunocompromised hosts as opportunistic infections. Host risk factors include diabetes mellitus, neutropenia, sustained immunosuppressive therapy, chronic prednisone use, iron chelation therapy, broad-spectrum antibiotic use, severe malnutrition, and primary breakdown in the integrity of the cutaneous barrier such as trauma, surgical wounds, needle sticks, or burns. Zygomycosis occurs only rarely in immunocompetent hosts. The disease manifestations reflect the mode of transmission, with rhinocerebral and pulmonary diseases being the most common manifestations. Cutaneous, gastrointestinal, and allergic diseases are also seen. The Mucorales are associated with angioinvasive disease, often leading to thrombosis, infarction of involved tissues, and tissue destruction mediated by a number of fungal proteases, lipases, and mycotoxins. If the diagnosis is not made early, dissemination often occurs. Therapy, if it is to be effective, must be started early and requires combinations of antifungal drugs, surgical intervention, and reversal of the underlying risk factors. The Entomophthorales are closely related to the Mucorales on the basis of sexual growth by production of zygospores and by the production of coenocytic hyphae. Despite these similarities, the Entomophthorales and Mucorales have dramatically different gross morphologies, asexual reproductive characteristics, and disease manifestations. In comparison to the floccose aerial mycelium of the Mucorales, the Entomophthorales produce a compact, glabrous mycelium. The asexually produced spores of the Entomophthorales may be passively released or actively expelled into the environment. Human disease with these organisms occurs predominantly in tropical regions, with transmission occurring by implantation of spores via minor trauma such as insect bites or by inhalation of spores into the sinuses. Conidiobolus typically infects mucocutaneous sites to produce sinusitis disease, while Basidiobolus infections occur as subcutaneous mycosis of the trunk and extremities. The Entomophthorales are true pathogens, infecting primarily immunocompetent hosts. They generally do not invade blood vessels and rarely disseminate. Occasional cases of disseminated and angioinvasive disease have recently been described, primarily in immunocompromised patients, suggesting a possible emerging role for this organism as an opportunist.

1,332 citations


Journal ArticleDOI
TL;DR: It is demonstrated that increased plasma concentrations of Ang II have profound and rapid effects on vascular pathology when combined with hyperlipidemia, in the absence of hemodynamic influences.
Abstract: Increased plasma concentrations of angiotension II (Ang II) have been implicated in atherogenesis. To examine this relationship directly, we infused Ang II or vehicle for 1 month via osmotic minipumps into mature apoE(-/-) mice. These doses of Ang II did not alter arterial blood pressure, body weight, serum cholesterol concentrations, or distribution of lipoprotein cholesterol. However, Ang II infusions promoted an increased severity of aortic atherosclerotic lesions. These Ang II-induced lesions were predominantly lipid-laden macrophages and lymphocytes; moreover, Ang II promoted a marked increase in the number of macrophages present in the adventitial tissue underlying lesions. Unexpectedly, pronounced abdominal aortic aneurysms were present in apoE(-/-) mice infused with Ang II. Sequential sectioning of aneurysmal abdominal aorta revealed two major characteristics: an intact artery that is surrounded by a large remodeled adventitia, and a medial break with pronounced dilation and more modestly remodeled adventitial tissue. Although no atherosclerotic lesions were visible at the medial break point, the presence of hyperlipidemia was required because infusions of Ang II into apoE(+/+) mice failed to generate aneurysms. These results demonstrate that increased plasma concentrations of Ang II have profound and rapid effects on vascular pathology when combined with hyperlipidemia, in the absence of hemodynamic influences.

1,262 citations


Journal ArticleDOI
TL;DR: A theoretical overview of some critical issues relevant to conditioned place preference is provided and it seems clear that CPP measures a learning process that is fundamentally distinct from drug self-administration.
Abstract: Rationale: Among the various experimental protocols that have been used to measure drug reward in laboratory animals, conditioned place preference (CPP) has been one of the most popular. However, a number of controversial issues have surrounded the use of this experimental protocol. Objective: The present review provides a theoretical overview of some critical issues relevant to CPP. The advantages and limitations of CPP are also covered. Results: Based on modern and traditional theoretical formulations of Pavlovian conditioning, CPP appears to reflect a preference for a context due to the contiguous association between the context and a drug stimulus. Within this theoretical framework, it seems clear that CPP measures a learning process that is fundamentally distinct from drug self-administration. The main advantages of CPP are that it: (1) tests animals in a drug-free state; (2) is sensitive to both reward and aversion; (3) allows for simultaneous determination of CPP and locomotor activity; (4) is adaptable to a variety of species; (5) typically yields dose-effect curves that are monophasic rather than biphasic; and (6) has utility in probing the neural circuits involved in drug reward. The main limitations of CPP are that it: (1) is subject to interpretation based on the notion of novelty seeking; (2) is cumbersome for providing the graded dose-effect curves needed for answering some pharmacological questions; (3) is difficult to interpret when animals prefer one context prior to drug conditioning; and (4) lacks face validity as an experimental protocol of drug reward in humans. Conclusion: Despite some limitations, CPP provides unique information about the rewarding effect of contextual cues associated with a drug stimulus.

1,184 citations


Journal ArticleDOI
TL;DR: A novel implementation of perfectly matched layer (PML) media is presented for the termination of FDTD lattices based on the stretched coordinate form of the PML, a recursive convolution, and the use of complex frequency, shifted (CFS) PML parameters.
Abstract: A novel implementation of perfectly matched layer (PML) media is presented for the termination of FDTD lattices. The implementation is based on the stretched coordinate form of the PML, a recursive convolution, and the use of complex frequency, shifted (CFS) PML parameters. The method, referred to here as the convolutional PML (CPML), offers a number of advantages over the traditional implementations of the PML. Specifically, the application of the CPML is completely independent of the host medium. Thus, no modifications are necessary when applying it to inhomogeneous, lossy, anisotropic, dispersive, or nonlinear media. Secondly, it is shown that the CFS–PML is highly absorptive of evanescent modes and can provide significant memory savings when computing the wave interaction of elongated structures, sharp corners, or low-frequency excitations. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 27: 334–339, 2000.

1,176 citations


Journal ArticleDOI
TL;DR: Positive behavior support (PBS) and functional behavioral assessment (FBA) are two significant concepts of the 1997 amendments to the Individuals with Disabilities Education Act (IDEA) as discussed by the authors.
Abstract: Positive behavior support (PBS) and functional behavioral assessment (FBA) are two significant concepts of the 1997 amendments to the Individuals with Disabilities Education Act. These two concepts...

1,013 citations


Journal ArticleDOI
TL;DR: Analytical challenges inherent in the interpretation of focus group data are described and approaches for enhancing the rigor of analysis and the reliability and validity of focus groups findings are suggested.
Abstract: In the literature on focus groups, far more attention has been devoted to how groups are organized and conducted than to issues of analysis. Although exploitation of group dynamics is touted as a virtue of focus groups, there is very little guidance in the literature with respect to how differences between group and individual discourse impact the analysis and interpretation of focus group data. In this article, the authors describe analytical challenges inherent in the interpretation of focus group data and suggest approaches for enhancing the rigor of analysis and the reliability and validity of focus group findings.

970 citations


Journal ArticleDOI
TL;DR: In this article, the authors examined the relation between the composition of financially distressed firms' audit committees and the likelihood of receiving going-concern reports for firms experiencing financial distress during 1994 and found that the greater the percentage of affiliated directors on the audit committee, the lower the probability the auditor will issue a going concern report.
Abstract: This study examines the relation between the composition of financially distressed firms' audit committees and the likelihood of receiving going‐concern reports For firms experiencing financial distress during 1994, we find that the greater the percentage of affiliated directors on the audit committee, the lower the probability the auditor will issue a going‐concern report These results support regulators' concern about financial‐reporting quality and the recent calls for more independent audit committees

928 citations


Journal ArticleDOI
TL;DR: The strengths and weaknesses of three approaches to measurement: managerial perceptions, firm behaviors, and resource allocations are examined, and it is suggested that measurement accuracy can be improved by using a triangulation of methods.

883 citations


Journal ArticleDOI
TL;DR: The ability of different enteric pathogens and coliforms to trigger agglutination of yeast cells (Saccharomyces cerevisiae, NCYC 1026) and a yeast cell wall preparation (MOS) was examined and had no effect on cecal concentrations of lactobacilli, enterococci, anaerobic bacteria, lactate, volatile fatty acid, or cECal pH.

Journal ArticleDOI
TL;DR: The PARP inhibitor 3-aminobenzamide (3AB) protects neurons against homocysteine-induced NAD depletion, loss of mitochondrial transmembrane potential, and cell death, demonstrating a requirement for PARP activation and/or NAD depletion in homocystite-induced apoptosis.
Abstract: Elevated plasma levels of the sulfur-containing amino acid homocysteine increase the risk for atherosclerosis, stroke, and possibly Alzheimer's disease, but the underlying mechanisms are unknown. We now report that homocysteine induces apoptosis in rat hippocampal neurons. DNA strand breaks and associated activation of poly-ADP-ribose polymerase (PARP) and NAD depletion occur rapidly after exposure to homocysteine and precede mitochondrial dysfunction, oxidative stress, and caspase activation. The PARP inhibitor 3-aminobenzamide (3AB) protects neurons against homocysteine-induced NAD depletion, loss of mitochondrial transmembrane potential, and cell death, demonstrating a requirement for PARP activation and/or NAD depletion in homocysteine-induced apoptosis. Caspase inhibition accelerates the loss of mitochondrial potential and shifts the mode of cell death to necrosis; inhibition of PARP with 3AB attenuates this effect of caspase inhibition. Homocysteine markedly increases the vulnerability of hippocampal neurons to excitotoxic and oxidative injury in cell culture and in vivo, suggesting a mechanism by which homocysteine may contribute to the pathogenesis of neurodegenerative disorders.

Journal ArticleDOI
01 Oct 2000-Leukemia
TL;DR: Data indicate that CD123 represents a unique marker for primitive leukemic stem cells and it is proposed that targeting of CD123 may be a promising strategy for the preferential ablation of AML cells.
Abstract: Recent studies suggest that the population of malignant cells found in human acute myelogenous leukemia (AML) arises from a rare population of leukemic stem cells (LSCs). LSCs have been documented for nearly all AML subtypes and have been phenotypically described as CD34+/CD38- or CD34+/HLA-DR-. Given the potentially critical role of these primitive cells in perpetuating leukemic disease, we sought to further investigate their molecular and cellular characteristics. Flow cytometric studies using primary AML tissue showed that the interleukin-3 receptor alpha chain (IL-3Ralpha or CD123) was strongly expressed in CD34+/CD38- cells (98 +/- 2% positive) from 16 of 18 primary specimens. Conversely, normal bone marrow derived CD34+/CD38- cells showed virtually no detectable expression of the CD123 antigen. To assess the functional role of IL-3Ralpha positive cells, purified CD34+/CD123+ leukemia cells were transplanted into immune deficient NOD/SCID mice. These experiments showed that CD123+ cells were competent to establish and maintain leukemic populations in vivo. To begin to elucidate a biological role for CD123 in leukemia, primary AML samples were analyzed with respect to signal transduction activity in the MAPK, Akt, and Stat5 pathways. Phosphorylation was not detected in response to IL-3 stimulation, thereby suggesting CD123 is not active in conventional IL-3-mediated signaling. Collectively, these data indicate that CD123 represents a unique marker for primitive leukemic stem cells. Given the strong expression of this receptor on LSCs, we propose that targeting of CD123 may be a promising strategy for the preferential ablation of AML cells.

Journal ArticleDOI
TL;DR: It is found that both assumptions about progeny size and fitness are supported by empirical studies but that the trade-off is less apparent when organisms are iteroparous, use adult-acquired resources for reproduction, or provide parental care.
Abstract: ▪ Abstract Most models of optimal progeny size assume that there is a trade-off between progeny size and number, and that progeny fitness increases with increasing investment per young. We find that both assumptions are supported by empirical studies but that the trade-off is less apparent when organisms are iteroparous, use adult-acquired resources for reproduction, or provide parental care. We then review patterns of variation in progeny size among species, among populations within species, among individuals within populations, and among progeny produced by a single female. We argue that much of the variation in progeny size among species, and among populations within species, is likely due to variation in natural selection. However, few studies have manipulated progeny environments and demonstrated that the relationship between progeny size and fitness actually differs among environments, and fewer still have demonstrated why selection favors different sized progeny in different environments. We argue ...

Journal ArticleDOI
TL;DR: The prevalence of restless legs in the general adult population is high and may be associated with decreased well-being, emphasizing the need for further research and greater medical recognition of this condition.
Abstract: Background Restless legs syndrome (RLS) is a disorder characterized by sleep-disrupting unpleasant leg sensations, often accompanied by daytime behavioral problems. Treatment for this condition is available, but it is suspected that most instances of RLS remain undiagnosed. The goal of this investigation was to assess the prevalence and health status correlates of restless legs symptoms (hereinafter referred to as restless legs) in the general population. Methods A question reflecting the clinical features of RLS was added to the 1996 Kentucky Behavioral Risk Factor Surveillance Survey. Data on the frequency of experiencing restless legs, self-rated general and mental health status, demographics, and behavioral risk factors were collected by telephone interview from 1803 men and women, 18 years and older. Results Experiencing restless legs 5 or more nights per month was reported by 3% of participants aged 18 to 29 years, 10% of those aged 30 to 79 years, and 19% of those 80 years and older. The age-adjusted prevalence for Kentucky adults is 10.0%; prevalence did not vary significantly by sex. The adjusted odds ratios (95% confidence intervals) for restless legs and diminished general health and poor mental health status were 2.4 (1.4-4.0) and 3.1 (2.0-4.6), respectively. Restless legs were significantly associated with increased age and body mass index, lower income, smoking, lack of exercise, low alcohol consumption, and diabetes. Conclusions The prevalence of restless legs in the general adult population is high. Restless legs may be associated with decreased well-being, emphasizing the need for further research and greater medical recognition of this condition.

Book
01 Jan 2000
TL;DR: In this paper, the existence of covers and envelopes of injective and projective comodules is studied and the projective dimension of a coalgebra is characterized. And the relation between injective, projective and injective co-occurrences is analyzed.
Abstract: We study classes of relative injective and projective comodules and extend well-known results about projective comodules given in [7]. The existence of covers and envelopes by these classes of comodules is also studied and used to characterize the projective dimension of a coalgebra. We also compare this homological coalgebra with the very intensively studied homological algebra of the dual algebra (see [5]).

Journal ArticleDOI
TL;DR: Significant evidence is outlined from multiidisciplinary approaches for amyloid beta-peptide-associated free radical oxidative stress and neurotoxicity and protection against these oxidative processes and cell death by free radical scavengers and the strong evidence supporting the notion that the single methionine residue of amyloids beta- peptide is vital to the oxidative Stress and neurotoxicological properties of this peptide.

Journal ArticleDOI
TL;DR: The data demonstrate that inhibition of Akt activation may play a crucial role in the induction of apoptosis by celecoxib, supported by studies showing that overexpression of constitutively active Akt protects PC-3 cells from Celecoxib-induced apoptosis.

Journal ArticleDOI
TL;DR: This article examined the relationship between large infrastructure spending, of the type implied by interstate highway construction, and the level of economic activity and found that highways have a differential impact across industries: certain industries grow as a result of reduced transportation costs, whereas others shrink as economic activity relocates.

Journal ArticleDOI
TL;DR: A descriptive framework for understanding factors that influence the success of knowledge management (KM) initiatives in an organization is introduced and identifies three main classes of influencing factors and characterizes the individual factors in each class.
Abstract: Modern organizations are increasingly seen as knowledge-based enterprises in which proactive knowledge management is important for competitiveness. This paper introduces a descriptive framework for understanding factors that influence the success of knowledge management (KM) initiatives in an organization. It identifies three main classes of influencing factors (managerial, resource, and environmental) and characterizes the individual factors in each class. A Delphi process was used to develop and assess the framework. The Delphi panel was comprised of 31 recognized researchers and practitioners in the KM field. The resultant framework can be used by researchers for KM issue and hypothesis generation, by practitioners for benchmarking KM practices, and by educators for helping organize the study of KM.

Journal ArticleDOI
TL;DR: For instance, this paper found that repetitive thought was positively correlated with anxiety and depression in students and negatively correlated with depression in patients, respectively, in a study with over 1000 participants.
Abstract: Worry and depressive rumination have both been described as unproductive, repetitive thought which contributes to anxiety or depression, respectively. It was hypothesized that repetitive thought, rather than its specific forms, is a general concomitant of negative mood. Study 1 was a cross-sectional test of the hypothesis. Repetitive thought was positively correlated with anxiety and depression in students (n = 110). In patients (n = 40), repetitive thought was positively correlated with anxiety and depression, and rumination was also specifically correlated with depression. Study 2 was a prospective test of the hypothesis. In students (n = 90), there were significant cross-sectional relationships between repetitive thought and both anxiety and depression. In addition, repetitive thought at least partially predicted maintenance of anxious symptoms. Phenomena such as goal interruption, failures of emotional processing, and information processing may lead to repetitive thought which increases negative mood states, including both anxiety and depression.


Journal ArticleDOI
TL;DR: Comparison of data from this trial with data from previous studies indicates that recurrent CDD may respond to a short course of high- dose vancomycin or to longer courses of low-dose vancomYcin when either is combined with S. boulardii.
Abstract: Recurrent Clostridium difficile disease (CDD) is a difficult clinical problem because antibiotic therapy often does not prevent further recurrences. In a previous study, the biotherapeutic agent Saccharomyces boulardii was used in combination with standard antibiotics and was found to be effective in reducing subsequent recurrences of CDD. In an effort to further refine a standard regimen, we tested patients receiving a regimen of a standard antibiotic for 10 days and then added either S. boulardii (1 g/day for 28 days) or placebo. A significant decrease in recurrences was observed only in patients treated with high-dose vancomycin (2 g/day) and S. boulardii (16.7%), compared with those who received high-dose vancomycin and placebo (50%; ). No serious adverse reactions were observed in these patients. ComP p .05

Journal ArticleDOI
TL;DR: Among the substantive findings were effects for sensation seeking, impulsivity, and agreeableness on all sexual risk-taking behaviors considered, and there were effects on specific behaviors for neuroticism and conscientiousness.
Abstract: Findings from a quantitative review of the empirical research literature on normal personality and sexual risk taking are reported. The review focuses on domains identified in major models of normal personality representing the psychobiological and taxonomic perspectives. Focal sexual risk-taking behaviors were number of partners, unprotected sex, and high-risk sexual encounters (e.g., sex with a stranger). A comprehensive search produced 53 studies relevant to the review. A striking feature of the results is the paucity of research on domains of normal personality and sexual risk taking for all domains other than sensation seeking, which accounted for 64% of the effect sizes. The preponderance of studies (81%) took the psychobiological perspective and were published since 1990 (75%). Among the substantive findings were effects for sensation seeking, impulsivity, and agreeableness on all sexual risk-taking behaviors considered. Additionally, there were effects on specific behaviors for neuroticism and conscientiousness. The implications of these findings for future research on normal personality and sexual risk taking are discussed.

Journal ArticleDOI
TL;DR: The American Thyroid Association recommends that adults be screened for thyroid dysfunction by measurement of the serum thyrotropin concentration, beginning at age 35 years and every 5 years thereafter.
Abstract: Objective To define the optimal approach to identify patients with thyroid dysfunction. Participants The 8-member Standards of Care Committee of the American Thyroid Association prepared a draft, which was reviewed by the association's 780 members, 50 of whom responded with suggested revisions. Evidence Relevant published studies were identified through MEDLINE and the association membership's personal resources. Consensus Process Consensus was reached at group meetings. The first draft was prepared by a single author (P.W.L.) after group discussion. Suggested revisions were incorporated after consideration by the committee. Conclusions The American Thyroid Association recommends that adults be screened for thyroid dysfunction by measurement of the serum thyrotropin concentration, beginning at age 35 years and every 5 years thereafter. The indication for screening is particularly compelling in women, but it can also be justified in men as a relatively cost-effective measure in the context of the periodic health examination. Individuals with symptoms and signs potentially attributable to thyroid dysfunction and those with risk factors for its development may require more frequent serum thyrotropin testing.

Journal ArticleDOI
01 Feb 2000-Synapse
TL;DR: Experiments in the hippocampal slice preparation suggest important roles for TNF and signaling pathways that modulate NF‐κB activity in regulation of hippocampal synaptic plasticity.
Abstract: The cytokine tumor necrosis factor-alpha (TNF), well-known for its roles in cellular responses to tissue injury, has recently been shown to be produced in response to physiological activity in neuronal circuits. TNF stimulates receptors in neurons linked to the activation of the transcription factor NF-kappaB, and recent findings suggest that this signaling pathway can modulate neuronal excitability and vulnerability of neurons to excitotoxicity. Because data indicate that TNF is produced, and NF-kappaB activated, under conditions associated with learning and memory, we performed experiments in the hippocampal slice preparation aimed at elucidating roles for TNF and NF-kappaB in modulating synaptic plasticity. Whereas stimulation of Schaffer collateral axons at a frequency of 1 Hz induced long-term depression (LTD) of synaptic transmission in region CA1 of wild-type mice, LTD did not occur in slices from TNF receptor knockout mice. Stimulation at 100 Hz induced long-term potentiation (LTP) in slices from both wild-type mice and mice lacking TNF receptors. Basal transmission was unaltered in mice lacking TNF receptors. Pretreatment of slices from wild-type mice with kappaB decoy DNA prevented induction of LTD and significantly reduced the magnitude of LTP. Collectively, these data suggest important roles for TNF and signaling pathways that modulate NF-kappaB activity in regulation of hippocampal synaptic plasticity.

Journal ArticleDOI
TL;DR: In this paper, the authors examined the requirement for the hemagglutinin (HA) for support of viral replication in horses, using viruses whose HAs differ in receptor specificity.
Abstract: The distribution of sialic acid (SA) species varies among animal species, but the biological role of this variation is largely unknown. Influenza viruses differ in their ability to recognize SA-galactose (Gal) linkages, depending on the animal hosts from which they are isolated. For example, human viruses preferentially recognize SA linked to Gal by the α2,6(SAα2,6Gal) linkage, while equine viruses favor SAα2,3Gal. However, whether a difference in relative abundance of specific SA species (N-acetylneuraminic acid [NeuAc] and N-glycolylneuraminic acid [NeuGc]) among different animals affects the replicative potential of influenza viruses is uncertain. We therefore examined the requirement for the hemagglutinin (HA) for support of viral replication in horses, using viruses whose HAs differ in receptor specificity. A virus with an HA recognizing NeuAcα2,6Gal but not NeuAcα2,3Gal or NeuGcα2,3Gal failed to replicate in horses, while one with an HA recognizing the NeuGcα2,3Gal moiety replicated in horses. Furthermore, biochemical and immunohistochemical analyses and a lectin-binding assay demonstrated the abundance of the NeuGcα2,3Gal moiety in epithelial cells of horse trachea, indicating that recognition of this moiety is critical for viral replication in horses. Thus, these results provide evidence of a biological effect of different SA species in different animals.

Journal ArticleDOI
TL;DR: Phylogenetic data and fossil evidence seem to support the PY→(PY+PD) evolutionary sequence in Anacardiaceae, which also may have occured in Leguminosae.
Abstract: Physical dormancy (PY) is caused by a water-impermeable seed or fruit coat. It is known, or highly suspected, to occur in nine orders and 15 families of angiosperms (sensuAngiosperm Phylogeny Group 1998), 13 of which are core eudicots. The Zingiberales is the only monocot order, and Cannaceae (Canna) the only monocot family, in which PY is known to occur. Six of the nine orders, and 12 of the 15 families, in which PY occurs are rosids. Furthermore, six of the families belong to the Malvales. The water-impermeable palisade layer(s) of cells are located in the seed coats of 13 of the families, and in the fruit coats of Anacardiaceae and Nelumbonaceae. In all 15 families, a specialized structure is associated with the water-impermeable layer(s). The breaking of PY involves disruption or dislodgment of these structures, which act as environmental ‘signal detectors’ for germination. Representatives of the nine angiosperm orders in which PY occurs had evolved by the late Cretaceous or early Tertiary (Paleogene). Anatomical evidence for PY in fruits of the extinct species Rhus rooseae (Anacardiaceae, middle Eocene) suggests that PY had evolved by 43Ma, and probably much earlier. We have constructed a conceptual model for the evolution of PY, and of PY+ physiological dormancy (PD), within Anacardiaceae. The model begins in pre-Eocene times with an ancestral species that has large, pachychalazal, non-dormant (ND), recalcitrant seeds. By the middle Eocene, a derived species with relatively small, partial pachychalazal, orthodox seeds and a water-impermeable endocarp (thus PY) had evolved, and by the Oligocene, PD had been added to the seed (true seed + endocarp) dormancy mechanism. It is suggested that climatic drying (Eocene), followed by climatic cooling (Eocene–Oligocene transition), were the primary selective agents in the development of PY. An evolutionary connection between PY and recalcitrance is suggested by the relatively high concentration of these two character states in the rosids. Phylogenetic data and fossil evidence seem to support the PY→(PY+PD) evolutionary sequence in Anacardiaceae, which also may have occured in Leguminosae.

Journal ArticleDOI
TL;DR: In this article, a simple vanilla method for using manifestos data to estimate party left-right positions is described. But the vanilla method consistently produces the best estimates of party positions, and these estimates are quite good (less than one point, on average, from the estimates of other accepted approaches).
Abstract: The left-right ideological positions of political parties play a central role in theorizing about many different aspects of democratic processes. Unfortunately, scholars are hindered in their ability to test existing theories by the limited availability of data that is comparable over time and across countries. This paper describes a simple 'vanilla' method for using manifestos data to estimate party leftright positions. It then tests this method and four existing ones by regressing a variety of accepted survey-based measures of left-right party positions on the estimates of party positions generated by the various techniques. Finally, analysis of the residuals from these regressions identifies the extent to which there are systematic sources of errors in using manifestos data to estimate party left-right positions. The vanilla method consistently produces the best estimates of party positions, and these estimates are quite good (less than one point, on average, from the estimates of other accepted approaches). Manifestos data, however, tend to locate extreme parties closer to the ideological center than do other survey-based approaches. he left-right ideological positions of political parties play a central role in theorizing many different aspects of democratic processes. Scholars employ the left-right positions of parties in theoretical arguments and empirical tests on such topics as macro-economic policymaking, legislative institutional choice, electoral competition, voting behavior, political representation, and cabinet stability. Thus, evaluation of a wide range of theoretical arguments in comparative politics requires reliable measures of the left-right positions of political parties. A practical problem facing scholars, however, is the limited availability of appropriate measures. There are two common sources of data on leftright party locations. One consists of expert surveys on specific party systems, where experts are asked to provide estimates of party left-right positions in these systems. Castles and Mair (1984) published the first such survey in a large number of countries, and results from a similar, subsequent survey are presented in Huber and Inglehart (1995).' Although these surveys are widely used to measure party positions, they suffer important limitations: they have been administered infrequently, in different formats, and only over the last fifteen years. A second source of data is the left-right positions of party supporters as reported in mass surveys such as the Eurobarometer or the World Values Survey. These surveys have been administered more frequently, but only over the last two decades and for a limited number of countries. Thus, scholars are frequently forced to limit their

Journal ArticleDOI
TL;DR: Successful nonoperative management was associated with higher blood pressure and hematocrit, and less severe injury based on ISS, Glasgow Coma Scale, grade of splenic injury, and quantity of hemoperitoneum.
Abstract: Background: Nonoperative management of blunt injury to the spleen in adults has been applied with increasing frequency. However, the criteria for nonoperative management are controversial. The purpose of this multi-institutional study was to determine which factors predict successful observation of blunt splenic injury in adults. Methods: A total of 1,488 adults (>15 years of age) with blunt splenic injury from 27 trauma centers in 1997 were studied through the Multi-institutional Trials Committee of the Eastern Association for the Surgery of Trauma. Statistical analysis was performed with analysis of variance and extended X 2 test. Data are expressed as mean ± SD; a value of p 15 were successfully observed. Frequency of immediate operation correlated with American Association for the Surgery of Trauma (AAST) grades of splenic injury: I (23.9%), II (22.4%), III (38.1%), IV (73.7%), and V (94.9%) (p < 0.05). Of patients initially managed nonoperatively, the failure rate increased significantly by AAST grade of splenic injury: I (4.8%), II (9.5%), III (19.6%), IV (33.3%), and V (75.0%) (p < 0.05). A total of 60.9% of the patients failed nonoperative management within 24 hours of admission; 8% failed 9 days or later after injury. Laparotomy was ultimately performed in 19.9% of patients with small hemoperitoneum, 49.4% of patients with moderate hemoperitoneum, and 72.6% of patients with large hemoperitoneum. Conclusion: In this multicenter study, 38.5% of adults with blunt splenic injury went directly to laparotomy. Ultimately, 54.8% of patients were successfully managed nonoperatively; the failure rate of planned observation was 10.8%, with 60.9% of failures occurring in the first 24 hours. Successful nonoperative management was associated with higher blood pressure and hematocrit, and less severe injury based on ISS, Glasgow Coma Scale, grade of splenic injury, and quantity of hemoperitoneum.