12 resultados para Synchronous generators

em BORIS: Bern Open Repository and Information System - Berna - Suiça


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Understanding the role of atmospheric CO2 during past climate changes requires clear knowledge of how it varies in time relative to temperature. Antarctic ice cores preserve highly resolved records of atmospheric CO2 and Antarctic temperature for the past 800,000 years. Here we propose a revised relative age scale for the concentration of atmospheric CO2 and Antarctic temperature for the last deglacial warming, using data from five Antarctic ice cores. We infer the phasing between CO2 concentration and Antarctic temperature at four times when their trends change abruptly. We find no significant asynchrony between them, indicating that Antarctic temperature did not begin to rise hundreds of years before the concentration of atmospheric CO2, as has been suggested by earlier studies.

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PURPOSE Metastatic renal cell carcinoma can be clinically diverse in terms of the pattern of metastatic disease and response to treatment. We studied the impact of metastasis and location on cancer specific survival. MATERIALS AND METHODS The records of 2,017 patients with renal cell cancer and tumor thrombus who underwent radical nephrectomy and tumor thrombectomy from 1971 to 2012 at 22 centers in the United States and Europe were analyzed. Number and location of synchronous metastases were compared with respect to patient cancer specific survival. Multivariable Cox regression models were used to quantify the impact of covariates. RESULTS Lymph node metastasis (155) or distant metastasis (725) was present in 880 (44%) patients. Of the patients with distant disease 385 (53%) had an isolated metastasis. The 5-year cancer specific survival was 51.3% (95% CI 48.6-53.9) for the entire group. On univariable analysis patients with isolated lymph node metastasis had a significantly worse cancer specific survival than those with a solitary distant metastasis. The location of distant metastasis did not have any significant effect on cancer specific survival. On multivariable analysis the presence of lymph node metastasis, isolated distant metastasis and multiple distant metastases were independently associated with cancer specific survival. Moreover higher tumor thrombus level, papillary histology and the use of postoperative systemic therapy were independently associated with worse cancer specific survival. CONCLUSIONS In our multi-institutional series of patients with renal cell cancer who underwent radical nephrectomy and tumor thrombectomy, almost half of the patients had synchronous lymph node or distant organ metastasis. Survival was superior in patients with solitary distant metastasis compared to isolated lymph node disease.

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We integrated research on the dimensionality of career success into social-cognitive career theory and explored the positive feedback loop between occupational self-efficacy and objective and subjective career success over time (self-efficacy → objective success → subjective success → self-efficacy). Furthermore, we theoretically accounted for synchronous and time-lagged effects, as well as indirect reciprocity between the variables. We tested the proposed model by means of longitudinal structural equation modeling in a 9-year four-wave panel design, by applying a model comparison approach and indirect effect analyses (N = 608 professionals). The findings supported the proposed positive feedback loop between occupational self-efficacy and career success. Supporting our time-based reasoning, the findings showed that unfolding effects between occupational self-efficacy and objective career success take more time (i.e., time-lagged or over time) than unfolding effects between objective and subjective career success, as well as between subjective career success and occupational self-efficacy (i.e., synchronous or concurrently). Indirect effects of past on future occupational self-efficacy via objective and subjective career success were significant, providing support for an indirect reciprocity model. Results are discussed with respect to extensions of social-cognitive career theory and occupational self-efficacy development over time.

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The deeply eroded West Gondwana Orogen is a major continental collision zone that exposes numerous occurrences of deeply subducted rocks, such as eclogites. The position of these eclogites marks the suture zone between colliding cratons, and the age of metamorphism constrains the transition from subduction-dominated tectonics to continental collision and mountain building. Here we investigate the metamorphic conditions and age of high-pressure and ultrahigh-pressure eclogites from Mali, Togo and NE-Brazil and demonstrate that continental subduction occurred within 20 million years over at least a 2,500-km-long section of the orogen during the Ediacaran. We consider this to be the earliest evidence of large-scale deep-continental subduction and consequent appearance of Himalayan-scale mountains in the geological record. The rise and subsequent erosion of such mountains in the Late Ediacaran is perfectly timed to deliver sediments and nutrients that are thought to have been necessary for the subsequent evolution of sustainable life on Earth.

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Gebiet: Chirurgie Abstract: Introduction: Carotid endarterectomy (CEA) and coronary artery bypass grafting (CABG) could be approached in a combined or a staged fashion. Some crucial studies have shown no significant difference in peri-operative stroke and death rate in combined versus staged CEA/CABG. At present conventional extracorporeal circulation (CECC) is regarded as the gold standard for performing on-pump coronary artery bypass grafting. On contrary, the use of minimized extracorporeal circulation (MECC) for CABG diminishes hemodilution, blood-air contact, foreign surface contact and inflammatory response. At the same time, general anaesthesia (GA) is a potential risk factor for higher perioperative stroke rate after isolated CEA, not only for the ipsilateral but also for the contralateral side especially in case of contralateral high-grade stenosis or occlusion. The aim of the study was to analyze if synchronous CEA/CABG using MECC (CEA/CABG group) allows reducing the perioperative stroke risk to the level of isolated CEA performed under GA (CEA-GA group). – Methods: A retrospective analysis of all patients who underwent CEA at our institution between January 2005 and December 2012 was performed. We compared outcomes between all patients undergoing CEA/CABG to all isolated CEA-GA during the same time period. The CEA/CABG group was additionally compared to a reference group consisting of patients undergoing isolated CEA in local anaesthesia. Primary outcome was in-hospital stroke. – Results: A total of 367 CEAs were performed, from which 46 patients were excluded having either off-pump CABG or other cardiac surgery procedures than CABG combined with CEA. Out of 321 patients, 74 were in the CEA/CABG and 64 in the CEA-GA group. There was a significantly higher rate of symptomatic stenoses among patients in the CEA-GA group (p<0.002). Three (4.1%) strokes in the CEA/CABG group were registered, two ipsilateral (2.7%) and one contralateral (1.4%) to the operated side. In the CEA-GA group 2 ipsilateral strokes (3.1%) occurred. No difference was noticed between the groups (p=1.000). One patient with stroke in each group had a symptomatic stenosis preoperatively. – Conclusions: Outcome with regard to mortality and neurologic injury is very good in both -patients undergoing CEA alone as well as patients undergoing synchronous CEA and CABG using the MECC system. Although the CEA/CABG group showed slightly increased risk of stroke, it can be considered as combined treatment in particular clinical situations.

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Eight synchronous pre-Roman cold phases were found at 9600–9200, 8600–8150, 7550–6900, 6600– 6200, 5350–4900, 4600–4400, 3500–3200 and 2600–2350 radiocarbon years BP by reconstructing past climate at two sites on the Swiss Plateau and at timberline in the Alps. The cooling events during the early-and mid-Holocene represent temperature values similar to today, and apparently the onset of cooling events represents a deviation from today's mean annual temperature of about 1°C and is triggered at a 1000-year periodicity. At Wallisellen-Langachermoos (440 m), a former oligotrophic lake near Zürich, the correlation between sum mertime lake levels and the seed production of the amphi-Atlantic aquatic plantNajas flexilis was used to reconstruct lake levels over a 3000-year period during the first part of the Holocene. At Lake Seedorf on the western Swiss Plateau (609 m) the sedimentological, palynological and macrofossil record revealed fluctuations of lake levels for the complete Holocene. From Lago Basso in the southern Alps (2250 m, Val San Giacomo near Splügen Pass, Northern Italy) the terrestrial plant macrofossils – especiallyPinus cembra andLarix – allowed the reconstruction of timberline fluctuations controlled by climate. A similar climatic pattern was found at Gouillé Rion pond in the central Swiss Alps (2343 m, Val d'Hérémence) with plant macrofossils and pollen concentrations and percentages. We postulate that these climatic events are detectable throughout central Europe by independent methods in combination with precise AMS-radiocarbon datings on terrestrial plant remains. Our data fit other proxy records of regional climatic change, such as cool intervals from Greenland ice cores, glacier movements in the Swiss and Austrian Alps, and dendro-densitometry on subfossil wood, as well as the palaeoclimatic data from the Jura Mountains of France obtained by sedimentological analyses. Thus our data indicate that the Northern Hemisphere climate was less stable during the Holocene than previously believed.