348 research outputs found

    A comparison of block and semi-parametric bootstrap methods for variance estimation in spatial statistics

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    Efron (1979) introduced the bootstrap method for independent data but it cannot be easily applied to spatial data because of their dependency. For spatial data that are correlated in terms of their locations in the underlying space the moving block bootstrap method is usually used to estimate the precision measures of the estimators. The precision of the moving block bootstrap estimators is related to the block size which is difficult to select. In the moving block bootstrap method also the variance estimator is underestimated. In this paper, first the semi-parametric bootstrap is used to estimate the precision measures of estimators in spatial data analysis. In the semi-parametric bootstrap method, we use the estimation of the spatial correlation structure. Then, we compare the semi-parametric bootstrap with a moving block bootstrap for variance estimation of estimators in a simulation study. Finally, we use the semi-parametric bootstrap to analyze the coal-ash data

    Memory, attention and fluency deficits in COPD may be a specific form of cognitive impairment

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    There is increasing evidence demonstrating an association between chronic obstructive pulmonary disease (COPD) and cognitive impairment. We present a narrative review of published studies on the subject and a cross-sectional study investigating domain-specific cognitive impairment in people with COPD compared to people with known Alzheimer's dementia, and controls without known COPD or cognitive impairment. The aim of the study was to compare prevalence and pattern of cognitive impairment between the three groups using the Addenbrooke's Cognitive Examination (ACE)-III tool. A total of 89 participants were recruited (44 with COPD, 17 with Alzheimer's and 28 controls). Patients with COPD had significantly lower total ACE-III scores than controls (p<0.001). When comparing the COPD group to the known Alzheimer's dementia group, overall ACE-III scores were significantly lower in the Alzheimer's dementia group than the COPD group (p=0.019). The domain-specific scores for attention (p<0.004), memory (p<0.004) and fluency (p<0.001) were significantly lower in the Alzheimer's dementia group than the COPD group. Our result suggest that the COPD group were significantly more likely to have cognitive impairment than the healthy control group. This was supported by the results of a narrative review of the published literature. Our results show that the pattern of impairment in the COPD group is different to the pattern of impairment shown in the known Alzheimer's dementia group, with significant differences in the cognitive domains affected. These results are in keeping with the findings of other previously published studies included in the narrative review

    Synergistic Monitoring – Addressing the Threats and Identifying Opportunities

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    For many years, land managers and scientists have been applying a variety of land treatments to improve or protect rangeland ecosystems. Collectively, we have studied the response of these treatments and wildfire events to identify opportunities for maintaining or improving Nevada sagebrush ecosystem health and functionality. In partnership with collaborators, we initiated a State-wide effort to capture, consolidate, and summarize implementation, monitoring, and research information for these events. We are conducting field studies to identify and fill information gaps. We seek a new and expanded information base that is available to Nevada land managers, scientists, and others interested in healthy and resilient sagebrush sites. We plan to identify the consequences of passive and active management; develop predictive tools for adaptive management; identify research needs; and increase accessibility to location, implementation and monitoring information for these events. Through the collaborative integration of our field study results with historic and current research and monitoring information, we seek to increase knowledge of landscape-level and site-specific ecological processes. This will further develop our ability to manage and predict rangeland health, integrity, resilience (after disturbance), and resistance (to undesired change under significant disturbance regimes) in the context of multiple-use management

    The 2005 Nevada Rangeland Vegetation Survey General Public Questionnaire and Survey of Responses

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    The 2005 Nevada Rangeland Vegetation Survey was conducted as a collaborative effort between the University of Nevada, Reno (UNR) Department of Resource Economics and the University of Nevada Cooperative Extension (UNCE) Natural Resources Program to fulfill two roles

    The Effect of Combination Spirulina–chitosan on Angiogenesis, Osteoclast, and Osteoblast Cells in Socket Models of Hyperglycemic Rattus norvegicus

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    Background: Prolongation of the inflammatory process in hyperglycemic interferes with bone formation, inhibits the healing process, and triggers bone resorption. A combination of spirulina and chitosan in the tooth socket of Rattus norvegicus is expected to promote the bone remodeling process. This study aimed to evaluate the effect of spirulina and chitosan on angiogenesis, osteoclast, and osteoblast cell in tooth socket models of type 1 diabetes. Materials and Methods: A laboratory‑based experiment involving 36 R. norvegicus, divided into three groups (nondiabetes mellitus (DM), uncontrolled DM, and controlled DM) and further divided into six subgroups. The controlled groups (K1, K2, and K3) were induced with 3% carboxymethyl cellulose Na, while the treated groups were induced with 12% spirulina and 20% chitosan. On the 14th day, the mandibles of the rats were removed. The capillary lumen, osteoblasts, and osteoclast cells were counted by hypothalamic–pituitary–adrenal examination and the results analyzed by means of Shapiro–Wilk, Levene’s, one‑way ANOVA, and post hoc Tukey’s honestly significant difference test. Results: There was a significant increment in the number of capillary lumen, osteoblast cells, and a decrease in osteoclasts in all three treated groups (P1, P2, and P3). Conclusions: A combination of spirulina and chitosan can effectively promote the healing process in postextraction sockets of type 1 DM R. norvegicus

    Tachyon search speeds up retrieval of similar sequences by several orders of magnitude

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    Summary: The usage of current sequence search tools becomes increasingly slower as databases of protein sequences continue to grow exponentially. Tachyon, a new algorithm that identifies closely related protein sequences ~200 times faster than standard BLAST, circumvents this limitation with a reduced database and oligopeptide matching heuristic
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