224 research outputs found

    Radiocarbon Analysis Confirms the Annual Nature of Sagebrush Growth Rings

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    In the Great Basin of North America, big sagebrush (Artemisia tridentata Nutt.) growth rings can be used to reconstruct environmental changes with annual resolution in areas where there is otherwise little such information available. We tested the annual nature of big sagebrush wood layers using accelerator mass spectrometry (AMS) radiocarbon dating. Four cross-sections from 3 sagebrush plants were collected near Ely, Nevada, USA, and analyzed using dendrochronological methods. Ten 14C measurements were then used to trace the location of the 1963–64 "bomb spike." Although the number of rings on each section did not exceed 60, crossdating was possible within a section and between sections. Years assigned to individual wood layers by means of crossdating aligned with their expected 14C values, matching the location of the 14C peak. This result confirmed the annual nature of growth rings formed by big sagebrush, and will facilitate the development of spatially explicit, well-replicated proxy records of environmental change, such as wildfire regimes, in Great Basin valleys

    Seismic Safety Margins Research Program load combination project, Task 3. Load combination methodology development. Interim report 1

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    This is the first interim report giving the results to date on the development of a load combination methodology. After a brief background, the objectives and scope of the load combination methodology task are listed. This is followed by user oriented requirements on the methodology. The proposed methodology is then introduced and simply demonstrated. Examples of similar applications of the reliability based methodology are presented and accompanied by a listing of some of the unique considerations in applying this type of methodology to nuclear design. A fairly detailed exposition of a component reliability and design code optimization scheme is given along with a brief discussion of system and plant reliability considerations

    Land management explains major trends in forest structure and composition over the last millennium in California's Klamath Mountains

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    For millennia, forest ecosystems in California have been shaped by fire from both natural processes and Indigenous land management, but the notion of climatic variation as a primary controller of the pre-colonial landscape remains pervasive. Understanding the relative influence of climate and Indigenous burning on the fire regime is key because contemporary forest policy and management are informed by historical baselines. This need is particularly acute in California, where 20th-century fire suppression, coupled with a warming climate, has caused forest densification and increasingly large wildfires that threaten forest ecosystem integrity and management of the forests as part of climate mitigation efforts. We examine climatic versus anthropogenic influence on forest conditions over 3 millennia in the western Klamath Mountains—the ancestral territories of the Karuk and Yurok Tribes—by combining paleoenvironmental data with Western and Indigenous knowledge. A fire regime consisting of tribal burning practices and lightning were associated with long-term stability of forest biomass. Before Euro-American colonization, the long-term median forest biomass was between 104 and 128 Mg/ha, compared to values over 250 Mg/ha today. Indigenous depopulation after AD 1800, coupled with 20th-century fire suppression, likely allowed biomass to increase, culminating in the current landscape: a closed Douglas fir–dominant forest unlike any seen in the preceding 3,000 y. These findings are consistent with precontact forest conditions being influenced by Indigenous land management and suggest large-scale interventions could be needed to return to historic forest biomass levels

    Is telemonitoring an option against shortage of physicians in rural regions? attitude towards telemedical devices in the North Rhine-Westphalian health survey, Germany

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    <p>Abstract</p> <p>Background</p> <p>General practitioners (GP) in rural areas of Germany are struggling to find successors for their private practices. Telemonitoring at home offers an option to support remaining GPs and specialists in ambulatory care.</p> <p>Methods</p> <p>We assessed the knowledge and attitude towards telemedicine in the population of North Rhine-Westphalia (NRW), Germany, in a population-based telephone survey.</p> <p>Results</p> <p>Out of 2,006 participants, 734 (36.6%) reported an awareness of telemedical devices. Only 37 participants (1.8%) have experience in using them. The majority of participants were in favour of using them in case of illness (72.2%). However, this approval declined with age. These findings were similar in rural and urban areas. Participants who were in favour of telemedicine (n = 1,480) strongly agreed that they would have to see their doctor less often, and that the doctor would recognize earlier relevant changes in their vital status. Participants who disliked to be monitored by telemedical devices preferred to receive immediate feedback from their physician. Especially, the elderly fear the loss of personal contact with their physician. They need the direct patient-physician communication.</p> <p>Conclusions</p> <p>The fear of being left alone with the technique needs to be compensated for today's elderly patients to enhance acceptance of home telemonitoring as support for remaining doctors either in the rural areas or cities.</p

    Phase-rectified signal averaging method to predict perinatal outcome in infants with very preterm fetal growth restriction- a secondary analysis of TRUFFLE-trial

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    BACKGROUND: Phase-rectified signal averaging, an innovative signal processing technique, can be used to investigate quasi-periodic oscillations in noisy, nonstationary signals that are obtained from fetal heart rate. Phase-rectified signal averaging is currently the best method to predict survival after myocardial infarction in adult cardiology. Application of this method to fetal medicine has established significantly better identification than with short-term variation by computerized cardiotocography of growth-restricted fetuses. OBJECTIVE: The aim of this study was to determine the longitudinal progression of phase-rectified signal averaging indices in severely growth-restricted human fetuses and the prognostic accuracy of the technique in relation to perinatal and neurologic outcome. STUDY DESIGN: Raw data from cardiotocography monitoring of 279 human fetuses were obtained from 8 centers that took part in the multicenter European “TRUFFLE” trial on optimal timing of delivery in fetal growth restriction. Average acceleration and deceleration capacities were calculated by phase-rectified signal averaging to establish progression from 5 days to 1 day before delivery and were compared with short-term variation progression. The receiver operating characteristic curves of average acceleration and deceleration capacities and short-term variation were calculated and compared between techniques for short- and intermediate-term outcome. RESULTS: Average acceleration and deceleration capacities and short-term variation showed a progressive decrease in their diagnostic indices of fetal health from the first examination 5 days before delivery to 1 day before delivery. However, this decrease was significant 3 days before delivery for average acceleration and deceleration capacities, but 2 days before delivery for short-term variation. Compared with analysis of changes in short-term variation, analysis of (delta) average acceleration and deceleration capacities better predicted values of Apgar scores <7 and antenatal death (area under the curve for prediction of antenatal death: delta average acceleration capacity, 0.62 [confidence interval, 0.19–1.0]; delta short-term variation, 0.54 [confidence interval, 0.13–0.97]; P=.006; area under the curve for prediction Apgar <7: average deceleration capacity <24 hours before delivery, 0.64 [confidence interval, 0.52–0.76]; short-term variation <24 hours before delivery, 0.53 [confidence interval, 0.40–0.65]; P=.015). Neither phase-rectified signal averaging indices nor short-term variation showed predictive power for developmental disability at 2 years of age (Bayley developmental quotient, <95 or <85). CONCLUSIONS: The phase-rectified signal averaging method seems to be at least as good as short-term variation to monitor progressive deterioration of severely growth-restricted fetuses. Our findings suggest that for short-term outcomes such as Apgar score, phase-rectified signal averaging indices could be an even better test than short-term variation. Overall, our findings confirm the possible value of prospective trials based on phase-rectified signal averaging indices of autonomic nervous system of severely growth-restricted fetuses

    Racial/Ethnic Differences in Multiple Self-Care Behaviors in Adults with Diabetes

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    OBJECTIVE: To assess racial/ethnic differences in multiple diabetes self-care behaviors. DESIGN: Cross-sectional study. PARTICIPANTS: 21,459 participants with diabetes in the 2003 Behavioral Risk Factor Surveillance survey. MEASUREMENTS: The study assessed self-care behaviors including physical activity, fruits/vegetables consumption, glucose testing, and foot examination, as well as a composite of the 4 self-care behaviors across racial/ethnic groups. Multiple logistic regression was used to assess the independent association between race/ethnicity, the composite variable, and each self-care behavior controlling for covariates. STATA was used for statistical analysis. RESULTS: Overall, 6% engaged in all 4 self-care behaviors, with a range of 5% in non-insulin users to 8% in insulin users. Blacks were less likely to exercise (OR 0.63, 95% CI 0.51, 0.79), while Hispanics and “others” were not significantly different from whites. Hispanics (OR 0.64, 95% CI 0.49, 0.82) and others (OR 0.69, 95% CI 0.49, 0.96) were less likely to do home glucose testing, while blacks were not significantly different from whites. Blacks (OR 1.42, 95% CI 1.12, 1.80) were more likely to do home foot examinations, while Hispanics and others were not significantly different from whites. Blacks (OR 0.56, 95% CI 0.36, 0.87) were less likely to engage in all 4 behaviors, while Hispanics and others were not significantly different from whites. There were no significant racial/ethnic differences in fruit and vegetable consumption. CONCLUSIONS: Few patients engage in multiple self-care behaviors at recommended levels, and there are significant racial/ethnic differences in physical activity, dietary, and foot care behaviors among adults with diabetes

    Tyrrhenian central Italy: Holocene population and landscape ecology

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    This paper compares changes in vegetation structure and composition (using synthetic fossil pollen data) with proxy data for population levels (including settlements and radiocarbon dates) over the course of the last 10 millennia in Tyrrhenian central Italy. These data show generalised patterns of clearance of woodland in response both to early agriculturalists and urbanism, as well as the specific adoption of tree crops and variations in stock grazing. The results provide a comprehensive understanding of the development of the anthropogenised landscape of one of the most important early centres of European civilisation, showing regional trends as well as local variations.</jats:p
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