975 resultados para Roth, Venla


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The stability of terrestrial carbon reservoirs is thought to be closely linked to variations in climate 1, but the magnitude of carbon–climate feedbacks has proved dificult to constrain for both modern 2–4 and millennial 5–13 timescales. Reconstructions of atmospheric CO2 concentrations for the past thousand years have shown fluctuations on multidecadal to centennial timescales 5–7, but the causes of these fluctuations are unclear. Here we report high-resolution carbon isotope measurements of CO2 trapped within the ice of the West Antarctic Ice Sheet Divide ice core for the past 1,000 years. We use a deconvolution approach 14 to show that changes in terrestrial organic carbon stores best explain the observed multidecadal variations in the 13 C of CO2 and in CO2 concentrations from 755 to 1850 CE. If significant long-term carbon emissions came from pre-industrial anthropogenic land-use changes over this interval, the emissions must have been offset by a natural terrestrial sink for 13 C-depleted carbon, such as peatlands. We find that on multidecadal timescales, carbon cycle changes seem to vary with reconstructed regional climate changes. We conclude that climate variability could be an important control of fluctuations in land carbon storage on these timescales.

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Vorbesitzer: Abraham Merzbacher. Paginierung in Prijs/Roth fehlerhaft, das Inhaltsverzeichnis befindet sich auf fol. 175. Bei der Neubearbeitung wurden die Schutzblätter am Ende des Bandes foliiert.

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Vorbesitzer: Abraham Merzbacher. Paginierung in Prijs/Roth fehlerhaft angegeben.

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OBJECTIVE To evaluate the long term oncological and functional outcomes after readaptation of the dorsolateral peritoneal layer following pelvic lymph node dissection (PLND) and cystectomy . PATIENTS AND METHODS A randomised, single-center, single-blinded, two-arm trial was conducted on 200 consecutive cystectomy patients who underwent PLND and cystectomy for bladder cancer (

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In the catchment basin of the Songwe River, the institutional order thwarts sustainable resource management. District borders obstruct coherent policy - and so does the national border between Malawi and Tanzania. Joint decision making will be necessary if matter are to improve.

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Manual used for the implementation of CDE's Geoprocessing courses in the South and East. Composed of 6 modules covering important aspects of GIS handling and implementation: 1) Introduction to GIS; 2) Management issues; 3) GIS data preparation; 4) GIS data presentation; 5) Vector data analysis; 6) Raster data analysis. At the moment the manual is designed for use with ArcGIS. Work on a manual for use with open source software is currently ongoing. This manual was successfully used during several GIS training events in Kenya and Tajikistan.

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by Cecil Roth

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OBJECTIVE To test whether sleep-deprived, healthy subjects who do not always signal spontaneously perceived sleepiness (SPS) before falling asleep during the Maintenance of Wakefulness Test (MWT) would do so in a driving simulator. METHODS Twenty-four healthy subjects (20-26 years old) underwent a MWT for 40 min and a driving simulator test for 1 h, before and after one night of sleep deprivation. Standard electroencephalography, electrooculography, submental electromyography, and face videography were recorded simultaneously to score wakefulness and sleep. Subjects were instructed to signal SPS as soon as they subjectively felt sleepy and to try to stay awake for as long as possible in every test. They were rewarded for both "appropriate" perception of SPS and staying awake for as long as possible. RESULTS After sleep deprivation, seven subjects (29%) did not signal SPS before falling asleep in the MWT, but all subjects signalled SPS before falling asleep in the driving simulator (p <0.004). CONCLUSIONS The previous results of an "inaccurate" SPS in the MWT were confirmed, and a perfect SPS was shown in the driving simulator. It was hypothesised that SPS is more accurate for tasks involving continuous feedback of performance, such as driving, compared to the less active situation of the MWT. Spontaneously perceived sleepiness in the MWT cannot be used to judge sleepiness perception while driving. Further studies are needed to define the accuracy of SPS in working tasks or occupations with minimal or no performance feedback.

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Cecil Roth