622 research outputs found
Segregation patterns of Neurospora chromosome ends: mapping chromosome tips.
Segregation patterns of Neurospora chromosome ends: mapping chromosome tips
Segregation patterns of Neurospora chromosome ends: mapping chromosome tips.
Segregation patterns of Neurospora chromosome ends: mapping chromosome tips
Atherosclerosis of the ascending aorta is a predictor of renal dysfunction after cardiac operations
AbstractObjectives: Renal dysfunction occurring after cardiac operations has been attributed to various factors, but the importance of an atherosclerotic thoracic aorta has not been previously evaluated. The purpose of this study was to identify predictors of postoperative renal dysfunction (50% or more increase from preoperative values) and to evaluate the importance of atherosclerosis of the ascending aorta as a predictor of this complication. Methods: Nine hundred seventy-eight consecutive patients, 50 years of age and older with normal preoperative renal function (serum creatinine level of 1.5 mg/dL or less), who were scheduled to undergo cardiac surgery were prospectively evaluated. Atherosclerosis of the ascending aorta was assessed during the operation (with epiaortic ultrasound), and patients were divided into 3 groups according to its severity (normal-to-mild, moderate, and severe). Results: Univariate predictors of renal dysfunction at postoperative day 1 were atherosclerosis of the ascending aorta (P < .045) and postoperative low cardiac output (P = .05); at postoperative day 6 they were atherosclerosis of the ascending aorta (P < .0001), postoperative low cardiac output (P < .0001), advanced age (P = .001), decreased preoperative left ventricular function (P = .01), and female gender (P = .03). Multivariate analysis showed that atherosclerosis of the ascending aorta (odds ratio, 3.06; P = .04) was the only independent predictor of postoperative renal dysfunction at day 1 and that postoperative low cardiac output (odds ratio, 4.83; P < .0001), atherosclerosis of the ascending aorta (odds ratio, 2.13; P = .0006), and preoperative left ventricular dysfunction (odds ratio, 1.48; P = .028) were independent predictors of postoperative renal dysfunction at day 6. Conclusions: An atherosclerotic ascending aorta is an important predictor of postoperative renal dysfunction, possibly because atheroembolism to the kidneys occurs in the perioperative period (ie, during surgical manipulation of an atherosclerotic aorta) or because the diseased aorta may be a marker of widespread atherosclerotic disease that may predispose to perioperative renal dysfunction. (J Thorac Cardiovasc Surg 1999;117:111-6
Using Analysis of Gini (ANoGi) for Detecting Whether Two Sub-Samples Represent the Same Universe: The SOEP Experience
A particular shortcoming of panel surveys is potential bias arising from selective attrition.
Based on data from the German Socio-Economic Panel Study (SOEP) we analyze potential
artifacts (level, structure, inequality of income) by comparing results from two independently
drawn panel sub-samples, started in 1984 and 2000, respectively. Both sub-samples carried
on using the same set of follow-up rules. We apply ANOGI (ANalysis Of GIni) techniques, the
equivalent of ANOVA (ANalysis Of VAriance) performed on the basis of the Gini coefficient.
The decomposition followed is presented in Yitzhaki (1994). We rearrange, reinterpret and
use the decomposition in the comparison of sub-populations from which the different subsamples
were drawn. Taking into account indicators for income, and for control purposes
those for education and satisfaction as well, significant differences between these two subsamples
with respect to (income) inequality are found in the first year, which start to fade
away in wave 2 and disappear in wave 3. We find credible indication for these differences to
be driven by changes in response behavior of short term panel members rather than by
attrition among members of the longer running sub-sample
Using Analysis of Gini (ANOGI) for Detecting Whether Two Subsamples Represent the Same Universe: The German Socio-Economic Panel Study (SOEP) Experience
A wildly discussed shortcoming of panel surveys is a potential bias arising from selective attrition. Based on data of the German Socio-Economic Panel Study (SOEP), the authors analyze potential artifacts (level, structure, income inequality) by comparing results for two independently drawn panel subsamples started in 1984 and 2000. They apply ANOGI (analysis of Gini) techniques, the equivalent of ANOVA performed with the Gini coefficient. They rearrange, reinterpret, and use the decomposition in the comparison of subpopulations from which the different samples were drawn. Taking into account indicators for income, significant differences between these two samples with respect to income inequality are found in the first year, which start to fade away in Wave 2 and disappear in Wave 3. The authors find credible indication for these differences to be driven by changes in response behavior of short-term panel members rather than by attrition among members of the longer running sample.Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich. - This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively
Independent individual addressing of multiple neutral atom qubits with a MEMS beam steering system
We demonstrate a scalable approach to addressing multiple atomic qubits for
use in quantum information processing. Individually trapped 87Rb atoms in a
linear array are selectively manipulated with a single laser guided by a MEMS
beam steering system. Single qubit oscillations are shown on multiple sites at
frequencies of ~3.5 MHz with negligible crosstalk to neighboring sites.
Switching times between the central atom and its closest neighbor were measured
to be 6-7 us while moving between the central atom and an atom two trap sites
away took 10-14 us.Comment: 9 pages, 3 figure
Dynamical differential equations compatible with rational qKZ equations
For the Lie algebra we introduce a system of differential operators
called the dynamical operators. We prove that the dynamical differential
operators commute with the rational quantized Knizhnik-Zamolodchikov
difference operators. We describe the transformations of the dynamical
operators under the natural action of the Weyl group.Comment: 7 pages, AmsLaTe
Quantum W-algebras and Elliptic Algebras
We define quantum W-algebras generalizing the results of Reshetikhin and the
second author, and Shiraishi-Kubo-Awata-Odake. The quantum W-algebra associated
to sl_N is an associative algebra depending on two parameters. For special
values of parameters it becomes the ordinary W-algebra of sl_N, or the
q-deformed classical W-algebra of sl_N. We construct free field realizations of
the quantum W-algebras and the screening currents. We also point out some
interesting elliptic structures arising in these algebras. In particular, we
show that the screening currents satisfy elliptic analogues of the Drinfeld
relations in U_q(n^).Comment: 26 pages, AMSLATE
Online Embeddings
13th International Workshop, APPROX 2010, and 14th International Workshop, RANDOM 2010, Barcelona, Spain, September 1-3, 2010. ProceedingsWe initiate the study of on-line metric embeddings. In such an embedding we are given a sequence of n points X = x [subscript 1],...,x [subscript n] one by one, from a metric space M = (X,D). Our goal is to compute a low-distortion embedding of M into some host space, which has to be constructed in an on-line fashion, so that the image of each x i depends only on x [subscript 1],...,x [subscript i] . We prove several results translating existing embeddings to the on-line setting, for the case of embedding into ℓ [subscript p] spaces, and into distributions over ultrametrics
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