University of Lisbon

About: University of Lisbon is a education organization based out in Lisbon, Lisboa, Portugal. It is known for research contribution in the topics: Population & European union. The organization has 19122 authors who have published 48503 publications receiving 1102623 citations. The organization is also known as: Universidade de Lisboa & Lisbon University.

The population history of northeastern Siberia since the Pleistocene

Abstract: Northeastern Siberia has been inhabited by humans for more than 40,000 years but its deep population history remains poorly understood. Here we investigate the late Pleistocene population history of northeastern Siberia through analyses of 34 newly recovered ancient genomes that date to between 31,000 and 600 years ago. We document complex population dynamics during this period, including at least three major migration events: an initial peopling by a previously unknown Palaeolithic population of ‘Ancient North Siberians’ who are distantly related to early West Eurasian hunter-gatherers; the arrival of East Asian-related peoples, which gave rise to ‘Ancient Palaeo-Siberians’ who are closely related to contemporary communities from far-northeastern Siberia (such as the Koryaks), as well as Native Americans; and a Holocene migration of other East Asian-related peoples, who we name ‘Neo-Siberians’, and from whom many contemporary Siberians are descended. Each of these population expansions largely replaced the earlier inhabitants, and ultimately generated the mosaic genetic make-up of contemporary peoples who inhabit a vast area across northern Eurasia and the Americas. Analyses of 34 ancient genomes from northeastern Siberia, dating to between 31,000 and 600 years ago, reveal at least three major migration events in the late Pleistocene population history of the region.

ATLAS b-jet identification performance and efficiency measurement with tt¯ events in pp collisions at √s = 13 TeV

Abstract: The algorithms used by the ATLAS Collaboration during Run 2 of the Large Hadron Collider to identify jets containing b-hadrons are presented. The performance of the algorithms is evaluated in the s ...

Awaji criteria for the diagnosis of amyotrophic lateral sclerosis:a systematic review.

Abstract: Objective To estimate the potential diagnostic added value of the Awaji criteria for diagnosis of a myotrophiclateral sclerosis (ALS), which have been compared with the previously accepted gold standard the revised El Escorial criteria in several studies. Data sources MEDLINE and Web of Science (until October2011). Study selection We searched for studies testing the diagnostic accuracy of the Awaji criteria vs the revised El Escorial criteria in patients referred with suspected ALS. Data extraction Evaluation and data extraction of identified studies were done independently. The Quality Assessment of Diagnostic Accuracy Studies list was used to assess study quality. We determined the proportion of patients classified as having probable/definite ALS and derived indices of diagnostic performance(sensitivity, specificity, and diagnostic odds ratio). Quantitative data synthesis was accomplished through random-effects meta-analysis, and heterogeneity was assessed with the I2 test. Data synthesis Eight studies were included (3 prospective and 5 retrospective) enrolling 1187 patients. Application of Awaji criteria led to a 23% (95% CI, 12% to 33%; I2=84%) increase in the proportion of patients classified as having probable/definite ALS. Diagnostic performance of the Awaji criteria was higher than the revised El Escorial criteria (pooled sensitivity: 81.1% [95%CI, 72.2% to 90.0%; I2=91%] vs 62.2% [95% CI, 49.4%to 75.1%; I2=93%]; pooled diagnostic odds ratio, 35.8[95% CI, 15.2 to 84.7; I2=3%] vs 8.7 [95% CI, 2.2 to 35.6;I2=50%]). Diagnostic accuracy of Awaji criteria was higher in bulbar- than in limb-onset cases. Conclusion The Awaji criteria have a significant clinical impact allowing earlier diagnosis and clinical trial entry in ALS.

The influence of precipitation pulses on soil respiration – Assessing the “Birch effect” by stable carbon isotopes

Abstract: Sudden pulse-like events of rapidly increasing CO 2 -efflux occur in soils under seasonally dry climates in response to rewetting after drought. These occurrences, termed “Birch effect”, can have a marked influence on the ecosystem carbon balance. Current hypotheses indicate that the “Birch” pulse is caused by rapidly increased respiration and mineralization rates in response to changing moisture conditions but the underlying mechanisms are still unclear. Here, we present data from an experimental field study using straight-forward stable isotope methodology to gather new insights into the processes induced by rewetting of dried soils and evaluate current hypotheses for the “Birch“-CO 2 -pulse. Two irrigation experiments were conducted on bare soil, root-free soil and intact vegetation during May and August 2005 in a semi-arid Mediterranean holm oak forest in southern Portugal. We continuously monitored CO 2 -fluxes along with their isotopic compositions before, during and after the irrigation. δ 13 C signatures of the first CO 2 -efflux burst, occurring immediately after rewetting, fit the hypothesis that the “Birch” pulse is caused by the rapid mineralization of either dead microbial biomass or osmoregulatory substances released by soil microorganisms in response to hypo-osmotic stress in order to avoid cell lyses. The response of soil CO 2 -efflux to rewetting was smaller under mild (May) than under severe drought (August) and isotopic compositions indicated a larger contribution of anaplerotic carbon uptake with increasing soil desiccation. Both length and severity of drought periods probably play a key role for the microbial response to the rewetting of soils and thus for ecosystem carbon sequestration.