50 research outputs found

    Variation of Maximum Tree Height and Annual Shoot Growth of Smith Fir at Various Elevations in the Sygera Mountains, Southeastern Tibetan Plateau

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    Little is known about tree height and height growth (as annual shoot elongation of the apical part of vertical stems) of coniferous trees growing at various altitudes on the Tibetan Plateau, which provides a high-elevation natural platform for assessing tree growth performance in relation to future climate change. We here investigated the variation of maximum tree height and annual height increment of Smith fir (Abies georgei var. smithii) in seven forest plots (30 m×40 m) along two altitudinal transects between 3,800 m and 4,200/4,390 m above sea level (a.s.l.) in the Sygera Mountains, southeastern Tibetan Plateau. Four plots were located on north-facing slopes and three plots on southeast-facing slopes. At each site, annual shoot growth was obtained by measuring the distance between successive terminal bud scars along the main stem of 25 trees that were between 2 and 4 m high. Maximum/mean tree height and mean annual height increment of Smith fir decreased with increasing altitude up to the tree line, indicative of a stress gradient (the dominant temperature gradient) along the altitudinal transect. Above-average mean minimum summer (particularly July) temperatures affected height increment positively, whereas precipitation had no significant effect on shoot growth. The time series of annual height increments of Smith fir can be used for the reconstruction of past climate on the southeastern Tibetan Plateau. In addition, it can be expected that the rising summer temperatures observed in the recent past and anticipated for the future will enhance Smith fir's growth throughout its altitudinal distribution range

    Durability of treatment effects of the Sleep Position Trainer versus oral appliance therapy in positional OSA: 12-month follow-up of a randomized controlled trial

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    The Sleep Position Trainer (SPT) is a new option for treating patients with positional obstructive sleep apnea (POSA). This study investigated long-term efficacy, adherence, and quality of life during use of the SPT device compared with oral appliance therapy (OAT) in patients with POSA. This prospective, multicenter trial randomized patients with mild to moderate POSA (apnea-hypopnea index [AHI] 5-30/h) to SPT or OAT. Polysomnography was performed at baseline and after 3 and 12 months' follow-up. The primary endpoint was OSA severity; adherence, quality of life, and adverse events were also assessed. Ninety-nine patients were randomized and 58 completed the study (29 in each group). Median AHI in the SPT group decreased from 13.2/h at baseline to 7.1/h after 12 months (P < 0.001); corresponding values in the OAT group were 13.4/h and 5.0/h (P < 0.001), with no significant between-group difference (P = 1.000). Improvements throughout the study were maintained at 12 months. Long-term median adherence was also similar in the two treatment groups; the proportion of patients who used their device for ≄ 4 h for 5 days in a week was 100% in the SPT group and 97.0% in the OAT group (P = 0.598). The efficacy of SPT therapy was maintained over 12 months and was comparable to that of OAT in patients with mild to moderate POSA. Adherence was relatively high, and similar in the two groups. www.clinicaltrials.gov (NCT02045576

    Study of breast cancer incidence in patients of lymphangioleiomyomatosis

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    Molecular evidence has linked the pathophysiology of lymphangioleiomyomatosis (LAM) to that of metastatic breast cancer. Following on this observation, we assessed the association between LAM and subsequent breast cancer. An epidemiological study was carried out using three LAM country cohorts, from Japan, Spain, and the United Kingdom. The number of incident breast cancer cases observed in these cohorts was compared with the number expected on the basis of the country-specific incidence rates for the period 2000–2014. Immunohistochemical studies and exome sequence analysis were performed in two and one tumors, respectively. All cohorts revealed breast cancer standardized incidence ratios (SIRs) ≄ 2.25. The combined analysis of all cases or restricted to pre-menopausal age groups revealed significantly higher incidence of breast cancer: SIR = 2.81, 95 % confidence interval (CI) = 1.32–5.57, P = 0.009; and SIR = 4.88, 95 % CI = 2.29–9.99, P = 0.0007, respectively. Immunohistochemical analyses showed positivity for known markers of lung metastatic potential. This study suggests the existence of increased breast cancer risk among LAM patients. Prospective studies may be warranted to corroborate this result, which may be particularly relevant for pre-menopausal women with LAM. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10549-016-3737-8) contains supplementary material, which is available to authorized users

    OSA and MAD

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    Results of TRIPOLI-4 version 10 on the TRIPOLI Criticality Validation Suite, Part 1,thermal spectra

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    International audienceThis paper presents the results of the latest version of TRIPOLI-4 [1] on its criticality validation suite, part I dedicated to thermal spectra. The criticality validation suite is made of 148 carefully chosen ICSBEP [2] benchmarks with various enrichments, fissile materials and spectra. The ICSBEP benchmarks computational models are prepared by the TRIPOLI-4 VetV team and are run in the same conditions for each benchmark initial source, number of neutrons per cycle, number of inactive and active cycles, keff estimator, nuclear data. Comparisons are made with the measured keff as well as with previous versions of TRIPOLI-4

    CO2 and vitamin B-12 interactions determine bioactive trace metal requirements of a subarctic Pacific diatom

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    Phytoplankton growth can be limited by numerous inorganic nutrients and organic growth factors. Using the subarctic diatom Attheya sp. in culture studies, we examined how the availability of vitamin B-12 and carbon dioxide partial pressure (pCO(2)) influences growth rate, primary productivity, cellular iron (Fe), cobalt (Co), zinc (Zn) and cadmium (Cd) quotas, and the net use efficiencies (NUEs) of these bioactive trace metals (mol C fixed per mol cellular trace metal per day). Under B-12-replete conditions, cells grown at high pCO(2) had lower Fe, Zn and Cd quotas, and used those trace metals more efficiently in comparison with cells grown at low pCO(2). At high pCO(2), B-12-limited cells had similar to 50% lower specific growth and carbon fixation rates, and used Fe similar to 15-fold less efficiently, and Zn and Cd similar to 3-fold less efficiently, in comparison with B-12-replete cells. The observed higher Fe, Zn and Cd NUE under high pCO(2)/B-12-replete conditions are consistent with predicted downregulation of carbon-concentrating mechanisms. Co quotas of B-12-replete cells were similar to 5- to 14-fold higher in comparison with B-12-limited cells, suggesting that >80% of cellular Co of B-12-limited cells was likely from B-12. Our results demonstrate that CO2 and vitamin B-12 interactively influence growth, carbon fixation, trace metal requirements and trace metal NUE of this diatom. This suggests the need to consider complex feedback interactions between multiple environmental factors for this biogeochemically critical group of phytoplankton in the last glacial maximum as well as the current and future changing ocean. The ISME Journal (2011) 5, 1388-1396; doi: 10.1038/ismej.2010.211; published online 20 January 201
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