Search results for "stratification"
showing 10 items of 210 documents
Aortic valve stenosis: Treatments options in elderly high-risk patients
2016
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Unbiased Estimators and Multilevel Monte Carlo
2018
Multilevel Monte Carlo (MLMC) and unbiased estimators recently proposed by McLeish (Monte Carlo Methods Appl., 2011) and Rhee and Glynn (Oper. Res., 2015) are closely related. This connection is elaborated by presenting a new general class of unbiased estimators, which admits previous debiasing schemes as special cases. New lower variance estimators are proposed, which are stratified versions of earlier unbiased schemes. Under general conditions, essentially when MLMC admits the canonical square root Monte Carlo error rate, the proposed new schemes are shown to be asymptotically as efficient as MLMC, both in terms of variance and cost. The experiments demonstrate that the variance reduction…
Benthic foraminiferal assemblage turnover during intensification of the Northern Hemisphere glaciation in the Piacenzian Punta Piccola section (South…
2012
Abstract We present the results of a high-resolution analysis of the benthic foraminiferal assemblages at the Punta Piccola section (Stratotype for the Piacenzian Stage), which spans the gradual climate transition of the intensification of the Northern Hemisphere glaciation (3.6–2.6 Ma). This study highlighted a major benthic foraminiferal fauna turnover, which started at about 3.05 Ma with LO of Cibicidoides italicus , registered the gradual decline of Stilostomella spp. and culminated at about 2.7–2.75 Ma, when the dominant Siphonina reticulata was replaced by Cibicidoides pachyderma , costate Bulimine, spinose Bulimine, spinose Uvigerine and the Bolivina dilatata group. Four compositiona…
Route to chaos in the weakly stratified Kolmogorov flow
2019
We consider a two-dimensional fluid exposed to Kolmogorov’s forcing cos(ny) and heated from above. The stabilizing effects of temperature are taken into account using the Boussinesq approximation. The fluid with no temperature stratification has been widely studied and, although relying on strong simplifications, it is considered an important tool for the theoretical and experimental study of transition to turbulence. In this paper, we are interested in the set of transitions leading the temperature stratified fluid from the laminar solution [U∝cos(ny),0, T ∝ y] to more complex states until the onset of chaotic states. We will consider Reynolds numbers 0 < Re ≤ 30, while the Richardson numb…
Forest types for biodiversity assessment at regional level: the case study of Sicily (Italy)
2007
Within Europe the question of plant coenosis is attracting growing interest. The quality and quantity of collected information on forest resources at a global level largely depends on the capacity to collect and analyse data at national and sub-national scale in a way compatible with those at global or continental levels. In Italy the acceptance of all the international agreements and protocols on the protection of the environment and management of natural resources, requires a standardization of collected information and statistics, with the aim to produce homogeneous and integrative data at global level. This need is reflected in the following points: (1) the adoption of a classification …
Frank W. Taussig and Carl S. Joslyn on the Social Origins of American Business Leaders: A Chapter in the History of Social Science at Harvard
2019
In their 1932 volume "American Business Leaders: A Study in Social Origins and Social Stratification," Frank W. Taussig and Carl S Joslyn, then a young Harvard graduate, argued that success in business depended more on innate superiority than on other environmental factors such as financial aid, influential connections, and formal education. The aim of this paper is to analyze the main contentions of Taussig and Joslyn, as well the intellectual genesis of, and the general reactions to, this controversial volume. Although our main focus is on Taussig and Joslyn, other figures, all directly affiliated with Harvard, will play a decisive role in our narrative—the economist Thomas Nixon Carver, …
Suggestive evidence for association of D2S2188 marker (2q31.1) with autism in 143 Sicilian (Italian) TRIO families
2005
We have screened 143 Sicilian (Italian) families with one autistic child to verify, by a linkage disequilibrium approach, the involvement of the 2q31.1 region in the cause of the disease in these families. Our study design includes the use of intrafamilial association to prevent a population stratification bias and ethnic homogeneity of the sample. The results of our analysis provided suggestive evidence of the occurrence of transmission disequilibrium between autism and the D2S2188 polymorphism in Sicilian TRIO families, a finding which provides further and independent support to the hypothesis of the existence of a susceptibility gene (or genes) for autism on chromosome 2q.
The advanced use of mobile phones in five European countries
2014
The paper explores the advanced users of mobile phones in Italy, France, Germany, Spain and the UK (EU5 countries) and aims to clarify the social meaning of advanced use. The mobile phone is seen as a strategic tool of social labour, whose capabilities are exploited to a different extent in the five studied countries. The analysis is based on a cross-national survey data collected in 2009 (N = 7,255). First, the results show that there are substantial differences in the advanced use of mobile phone and its predictors in Europe. Generally, only about one third of the studied mobile features are exploited. British and French people are the most advanced users, followed by German, Spanish and …
Sclerochronological evidence of pronounced seasonality from the late Pliocene of the southern North Sea basin and its implications
2022
Oxygen isotope (δ18O) sclerochronology of benthic marine molluscs provides a means of reconstructing the seasonal range in seafloor temperature, subject to use of an appropriate equation relating shell δ18O to temperature and water δ18O, a reasonably accurate estimation of water δ18O, and due consideration of growth-rate effects. Taking these factors into account, δ18O data from late Pliocene bivalves of the southern North Sea basin (Belgium and the Netherlands) indicate a seasonal seafloor range a little smaller than now in the area. Microgrowth-increment data from Aequipecten opercularis, together with the species composition of the bivalve assemblage and aspects of preservation, suggest …
Akute Lungenembolie – Eine kritische Übersicht über aktuelle Leitlinien und Empfehlungen
2013
Die akute Lungenembolie (LE) ist eine haufige und potenziell lebensbedrohliche Erkrankung. Dieser Artikel bietet eine kritische Ubersicht uber die aktuellen Leitlinien und Empfehlungen fur das Management der akuten LE. Die Symptome und klinischen Zeichen sind unspezifisch und umfassen Dyspnoe, Brustschmerzen, Hamoptyse, Synkope, arterielle Hypotension und Schock. Bei Patienten mit klinischem Verdacht auf akute LE sollte umgehend das Vorliegen eines hohen Risikos aufgrund hamodynamischer Instabilitat festgestellt oder ausgeschlossen werden. Dies wird ein risikoadaptiertes diagnostisches und therapeutisches Vorgehen ermoglichen. Nach Semiquantifizierung der klinischen Wahrscheinlichkeit einer…