2,488 research outputs found

    Measurements of pernitric acid at the South Pole during ISCAT 2000

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    The first measurements of pernitric acid at the South Pole were performed during the second Investigation of Sulfur Chemistry in the Antarctic Troposphere (ISCAT 2000). Observed HO2NO2 concentrations averaged 25 pptv. Simple steady-state calculations constrained by measurements show that the lifetime of pernitric acid was largely controlled by dry deposition, with thermal decomposition becoming increasingly important at warmer temperatures. We determined that the pernitric acid equilibrium constant is less uncertain than indicated in the literature. One consequence of pernitric acid deposition to the snow surface is that it is an important sink for both NOx and HOx. Another is that the photochemistry of HO2NO2 in the Antarctic snowpack may be a NOx source in addition to nitrate photolysis. This might be one of the important differences in snow photochemistry between the South Pole and warmer polar sites

    Siting prisons, sighting communities: geographies of objection in a planning process

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    This paper reviews the planning process for a Scottish prison located near a former mining village. Analysing the letters of objection submitted by residents offers an opportunity to explore local views about prison and community and to relate these to the unique social and spatial history of the area. The planning process itself structured how residents were able to express themselves and defined what counted as a relevant objection. After deconstructing this process, the paper then restores and uses as a framework for analysis three geographies of objection stripped from local responses to the development proposal: the emotional, temporal, and spatial. Emotional expressions of objection added intensity and gave meaning to claims about the historical decline of the region and also conveyed a deep sense of the proposed building site as a lived space. Particular grounds of opposition—over fear of strangers, the fragility of a local orchid, and the pollution from mining—provide an opportunity to explore the complex nature of place meaning and community identity, ultimately leading to a conclusion that the meaning of place is always in flux. The paper argues that Simmel’s classic concept of the stranger, as the outsider who comes to stay, offers a useful analytic in understanding how the quality of proximal remoteness that prisons and other unwanted developments constitute participates in a constantly evolving sense of the local

    The 18-Year Risk of Cancer, Angioedema, Insomnia, Depression, and Erectile Dysfunction in Association With Antihypertensive Drugs: Post-Trial Analyses From ALLHAT-Medicare Linked Data

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    PURPOSE: This study aimed to determine the 18-year risk of cancer, angioedema, insomnia, depression, and erectile dysfunction in association with antihypertensive drug use. METHODS: This is a post-trial passive follow-up study of Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) participants between 1994 and 1998 that was conducted by linking their follow-up data with Medicare claims data until 2017 of subjects who were free of outcomes at baseline on 1 January 1999. The main outcomes were the occurrence of cancer (among RESULTS: The 18-year cumulative incidence rate of cancer other than non-melanoma skin cancer from Medicare inpatient claims was 23.9% for chlorthalidone, 23.4% for amlodipine, and 25.3% for lisinopril. There were no statistically significant differences in the 18-year risk of cancer, depression, and erectile dysfunction among the three drugs based on the adjusted hazard ratios. The adjusted 18-year risk of angioedema was elevated in those receiving lisinopril than in those receiving amlodipine (hazard ratio: 1.63, 95% CI: 1.14-2.33) or in those receiving chlorthalidone (1.33, 1.00-1.79), whereas the adjusted 18-year risk of insomnia was statistically significantly decreased in those receiving lisinopril than in those receiving amlodipine (0.90, 0.81-1.00). CONCLUSIONS: The 18-year risk of angioedema was significantly higher in patients receiving lisinopril than in those receiving amlodipine or chlorthalidone; the risk of insomnia was significantly lower in patients receiving lisinopril than in those receiving amlodipine; and the risk of cancer, depression, and erectile dysfunction (in men) was not statistically significantly different among the three drug groups

    Direct Fitness Correlates and Thermal Consequences of Facultative Aggregation in a Desert Lizard

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    Social aggregation is a common behavioral phenomenon thought to evolve through adaptive benefits to group living. Comparing fitness differences between aggregated and solitary individuals in nature – necessary to infer an evolutionary benefit to living in groups – has proven difficult because communally-living species tend to be obligately social and behaviorally complex. However, these differences and the mechanisms driving them are critical to understanding how solitary individuals transition to group living, as well as how and why nascent social systems change over time. Here we demonstrate that facultative aggregation in a reptile (the Desert Night Lizard, Xantusia vigilis) confers direct reproductive success and survival advantages and that thermal benefits of winter huddling disproportionately benefit small juveniles, which can favor delayed dispersal of offspring and the formation of kin groups. Using climate projection models, however, we estimate that future aggregation in night lizards could decline more than 50% due to warmer temperatures. Our results support the theory that transitions to group living arise from direct benefits to social individuals and offer a clear mechanism for the origin of kin groups through juvenile philopatry. The temperature dependence of aggregation in this and other taxa suggests that environmental variation may be a powerful but underappreciated force in the rapid transition between social and solitary behavior

    Risk of Developing alzheimer\u27s Disease and Related Dementias in allhat Trial Participants Receiving Diuretic, ace-inhibitor, or Calcium-Channel Blocker With 18 Years of Follow-Up

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    BACKGROUND: There is no any large randomized clinical trial of antihypertensive drug treatment with 18-year passive follow-up to examine the risk of Alzheimer\u27s Disease (AD) or Related Dementias (ADRD). METHODS: Post-trial passive follow-up study of Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) participants in 1994-1998 by linking with their Medicare claims data through 2017 among 17,158 subjects in 567 U.S. centers who were free of ADRD at baseline on January 1, 1999. Main outcome was the occurrence of ADRD over 18 years of follow-up. RESULTS: The 18-year cumulative incidence rates were 30.9% for AD, 59.2% for non-AD dementias, and 60.9% for any ADRD. The 18-year cumulative incidence of AD was almost identical for the 3 drug groups (30.5% for chlorthalidone, 31.1% for amlodipine, and 31.4% for lisinopril). The hazard ratios of AD, non-AD dementias and total ADRD were not statistically significantly different among the 3 drug groups. The adjusted hazard ratio of AD was 1.04 (95% CI: 0.94-1.14) for chlorthalidone CONCLUSION: The risk of ADRD did not vary significantly by 3 antihypertensive drugs in ALLHAT trial participants with 18-years of follow-up. The risk of ADRD was significantly associated with age, gender, race/ethnicity, education, and history of vascular diseases

    Mortality and Morbidity among individuals With Hypertension Receiving a Diuretic, ace inhibitor, or Calcium Channel Blocker: a Secondary analysis of a Randomized Clinical Trial

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    IMPORTANCE: The long-term relative risk of antihypertensive treatments with regard to mortality and morbidity is not well understood. OBJECTIVE: to determine the long-term posttrial risk of primary and secondary outcomes among trial participants who were randomized to either a thiazide-type diuretic, calcium channel blocker (CCB), or angiotensin-converting enzyme (ACE) inhibitor with up to 23 years of follow-up. DESIGN, SETTING, AND PARTICIPANTS: This prespecified secondary analysis of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT), a multicenter randomized, double-blind, active-controlled clinical trial, followed up with participants aged 55 years or older with a diagnosis of hypertension and at least 1 other coronary heart disease risk factor for up to 23 years, from February 23, 1994, to December 31, 2017. Trial participants were linked with administrative databases for posttrial mortality (N = 32 804) and morbidity outcomes (n = 22 754). Statistical analysis was performed from January 2022 to October 2023. INTERVENTIONS: Participants were randomly assigned to receive a thiazide-type diuretic (n = 15 002), a CCB (n = 8898), or an ACE inhibitor (n = 8904) for planned in-trial follow-up of approximately 4 to 8 years and posttrial passive follow-up for up to 23 years. MAIN OUTCOMES AND MEASURES: The primary end point was mortality due to cardiovascular disease (CVD). Secondary outcomes included all-cause mortality, combined fatal and nonfatal (morbidity) CVD, and both mortality and morbidity for coronary heart disease, stroke, heart failure, end-stage renal disease, and cancer. RESULTS: A total of 32 804 participants (mean [SD] age, 66.9 [7.7] years; 17 411 men [53.1%]; and 11 772 Black participants [35.9%]) were followed up for all-cause mortality and a subgroup of 22 754 participants (mean [SD] age, 68.7 [7.2] years; 12 772 women [56.1%]; and 8199 Black participants [36.0%]) were followed up for fatal or nonfatal CVD through 2017 (mean [SD] follow-up, 13.7 [6.7] years; maximum follow-up, 23.9 years). Cardiovascular disease mortality rates per 100 persons were 23.7, 21.6, and 23.8 in the diuretic, CCB, and ACE inhibitor groups, respectively, at 23 years after randomization (adjusted hazard ratio [AHR], 0.97 [95% CI, 0.89-1.05] for CCB vs diuretic; AHR, 1.06 [95% CI, 0.97-1.15] for ACE inhibitor vs diuretic). The long-term risks of most secondary outcomes were similar among the 3 groups. Compared with the diuretic group, the ACE inhibitor group had a 19% increased risk of stroke mortality (AHR, 1.19 [95% CI, 1.03-1.37]) and an 11% increased risk of combined fatal and nonfatal hospitalized stroke (AHR, 1.11 [95% CI, 1.03-1.20]). CONCLUSIONS AND RELEVANCE: In this secondary analysis of a randomized clinical trial in an adult population with hypertension and coronary heart disease risk factors, CVD mortality was similar between all 3 groups. ACE inhibitors increased the risk of stroke outcomes by 11% compared with diuretics, and this effect persisted well beyond the trial period. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT00000542

    A Cepheid Distance to NGC 4603 in Centaurus

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    In an attempt to use Cepheid variables to determine the distance to the Centaurus cluster, we have obtained images of NGC 4603 with the Hubble Space Telescope on 9 epochs using WFPC2 and the F555W and F814W filters. This galaxy has been suggested to lie within the ``Cen30'' portion of the cluster and is the most distant object for which this method has been attempted. Previous distance estimates for Cen30 have varied significantly and some have presented disagreements with the peculiar velocity predicted from redshift surveys, motivating this investigation. Using our observations, we have found 61 candidate Cepheid variable stars; however, a significant fraction of these candidates are likely to be nonvariable stars whose magnitude measurement errors happen to fit a Cepheid light curve of significant amplitude for some choice of period and phase. Through a maximum likelihood technique, we determine that we have observed 43 +/- 7 real Cepheids and that NGC 4603 has a distance modulus of 32.61 +0.11/-0.10 (random, 1 sigma) +0.24/-0.25 (systematic, adding in quadrature), corresponding to a distance of 33.3 Mpc. This is consistent with a number of recent estimates of the distance to NGC 4603 or Cen30 and implies a small peculiar velocity consistent with predictions from the IRAS 1.2 Jy redshift survey if the galaxy lies in the foreground of the cluster.Comment: Accepted for publication in the Astrophysical Journal. 17 pages with 17 embedded figures and 3 tables using emulateapj.sty. Additional figures and images may be obtained from http://astro.berkeley.edu/~marc/n4603

    Lack of a significant legacy effect of baseline blood pressure 'treatment naivety' on all-cause and cardiovascular mortality in the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial

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    Objectives: To investigate legacy effects at 14-year follow-up of all-cause and cardiovascular disease (CVD) mortality in 'treatment-naive' or 'previous treatment' groups based on blood pressure (BP)-lowering treatment status at baseline. Methods: A post-hoc observational study of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial. We excluded participants with a previous history of CVD events. Cox proportional hazard model and 95% confidence interval were used to estimate the effects of treatment naive on mortality outcomes. Moreover, a subgroup analysis by estimated 10-year Framingham risk score was performed. Results: In multivariable models adjusting for baseline and in-trial characteristics (BP values and number of BP medications as time-dependent variables), there was no statistically significant difference in 5 and 14-year all-cause mortality with a hazard ratio of 0.93 (95% confidence interval 0.80-1.09) and hazard ratio 0.95 (0.88-1.03) and in 5 and 14-year CVD mortality hazard ratio 0.94 (0.72-1.23) and hazard ratio 0.93 (0.80-1.08). In subgroup by absolute CVD risk, no heterogeneity of the association between treatment naive and short-term or long-term all-cause or CVD mortality were found. All comparisons are between the treatment-naive and previous treatment groups. Conclusion: Physicians are concerned about 'legacy effects' of not treating individuals with a BP of 140 mmHg or over and low absolute risk. When treatment intensification was taken into consideration in the primary prevention population in this study, no adverse legacy effect as a result of baseline BP 'treatment naivety' was evident in 14 years of follow-up. The nonsignificant associations were consistent across the CVD risk subgroups. However, the results may be biased due to unobserved residual confounding and therefore should be interpreted with caution

    On the segmentation and classification of hand radiographs

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    This research is part of a wider project to build predictive models of bone age using hand radiograph images. We examine ways of finding the outline of a hand from an X-ray as the first stage in segmenting the image into constituent bones. We assess a variety of algorithms including contouring, which has not previously been used in this context. We introduce a novel ensemble algorithm for combining outlines using two voting schemes, a likelihood ratio test and dynamic time warping (DTW). Our goal is to minimize the human intervention required, hence we investigate alternative ways of training a classifier to determine whether an outline is in fact correct or not. We evaluate outlining and classification on a set of 1370 images. We conclude that ensembling with DTW improves performance of all outlining algorithms, that the contouring algorithm used with the DTW ensemble performs the best of those assessed, and that the most effective classifier of hand outlines assessed is a random forest applied to outlines transformed into principal components
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