2,580 research outputs found
Political economy and life course patterns: the heterogeneity of occupational, family and household trajectories of young spaniards
We explore the strong linkages between macro changes and the dynamics of educational, occupational, family, and residential careers of young Spanish adults born between 1945 and 1974. We review theory and evidence on macro factors: changes in the welfare system, centrality of the family as a service provider, and the changing role of women. We outline some hypotheses of how life course trajectories, and their heterogeneity, change across cohorts. We build data on sequences of states using FFS. In our analysis, we find an increase in the discontinuity of careers and of the heterogeneity among cohort members, especially for employment. Women´s careers are becoming more similar to those of men. Family and household formation is postponed, with a limited spread of post-nuclear family forms.
Cohabitation, marriage, first birth: the interrelationship of family formation events in Spain
In this paper we investigate (1) the mutual causal relationship between first union formation and first childbirth, and (2) the existence of constant common determinants of these two events. It is argued that (unmeasured) common factors reflect differentials among the population in value orientations and in norms about the sequencing of events. We apply event history techniques to retrospective survey data for Spain, allowing for the correlation between unobserved heterogeneity components belonging to each process. Our findings confirm the strong interrelationship between union formation and first birth. After controlling for these common factors, we find that the risk of conception increases immediately at marriage, and it continues to be high during the following four years. Entry into cohabitation produces much smaller increases in the relative risk. The effect of the conception of the first child on union formation is especially strong during pregnancy, but declines sharply after delivery.
Leaving home in Europe: the experience of cohorts born around 1960
In this paper we analyse the leaving home experience of men and women born around 1960 in 16 European countries. We use extensive empirical evidence from Fertility and Family Survey data, providing a large-scale comparison. We focus on some key indicators of the process of leaving home: the timing, sequencing and synchronisation of leaving home with the end of education and the formation of a first union. As far as these dimensions of leaving home are concerned, Europe appears to be extremely heterogeneous, and explaining this will undoubtedly be a challenge. The complex interplay between the present economic situation of young people and long-term institutional and cultural factors is thought to be the main driving factor. Our findings constitute a benchmark against which subsequent behaviour, such as that of cohorts coming of age after the fall of the Iron Curtain, could be compared. (AUTHORS)Europe
Instability and new phases of higher-dimensional rotating black holes
It has been conjectured that higher-dimensional rotating black holes become
unstable at a sufficiently large value of the rotation, and that new black
holes with pinched horizons appear at the threshold of the instability. We
search numerically, and find, the stationary axisymmetric perturbations of
Myers-Perry black holes with a single spin that mark the onset of the
instability and the appearance of the new black hole phases. We also find new
ultraspinning Gregory-Laflamme instabilities of rotating black strings and
branes.Comment: 5 pages, 5 figures. The instability of the black hole is argued to
appear at the second zero mode. The first zero mode is not associated to a
new branch of black hole solution
Study of meta-analysis strategies for network inference using information-theoretic approaches
© 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Reverse engineering of gene regulatory networks (GRNs) from gene expression data is a classical challenge in systems biology. Thanks to high-throughput technologies, a massive amount of gene-expression data has been accumulated in the public repositories. Modelling GRNs from multiple experiments (also called integrative analysis) has; therefore, naturally become a standard procedure in modern computational biology. Indeed, such analysis is usually more robust than the traditional approaches focused on individual datasets, which typically suffer from some experimental bias and a small number of samples.
To date, there are mainly two strategies for the problem of interest: the first one (”data merging”) merges all datasets together and then infers a GRN whereas the other (”networks ensemble”) infers GRNs from every dataset separately and then aggregates them using some ensemble rules (such as ranksum or weightsum). Unfortunately, a thorough comparison of these two approaches is lacking.
In this paper, we evaluate the performances of various metaanalysis approaches mentioned above with a systematic set of experiments based on in silico benchmarks. Furthermore, we present a new meta-analysis approach for inferring GRNs from multiple studies. Our proposed approach, adapted to methods based on pairwise measures such as correlation or mutual information, consists of two steps: aggregating matrices of the pairwise measures from every dataset followed by extracting the network from the meta-matrix.Peer ReviewedPostprint (author's final draft
Atrial cellular electrophysiological changes in patients with ventricular dysfunction may predispose to AF
<b>Background:</b>
Left ventricular systolic dysfunction (LVSD) is a risk factor for atrial fibrillation (AF), but the atrial cellular electrophysiological mechanisms in humans are unclear.
Objective
This study sought to investigate whether LVSD in patients who are in sinus rhythm (SR) is associated with atrial cellular electrophysiological changes that could predispose to AF.
<b>Methods:</b>
Right atrial myocytes were obtained from 214 consenting patients in SR who were undergoing cardiac surgery. Action potentials or ion currents were measured using the whole-cell-patch clamp technique.
<b>Results:</b>
The presence of moderate or severe LVSD was associated with a shortened atrial cellular effective refractory period (ERP) (209 ± 8 ms; 52 cells, 18 patients vs 233 ± 7 ms; 134 cells, 49 patients; P <0.05); confirmed by multiple linear regression analysis. The left ventricular ejection fraction (LVEF) was markedly lower in patients with moderate or severe LVSD (36% ± 4%, n = 15) than in those without LVSD (62% ± 2%, n = 31; P <0.05). In cells from patients with LVEF ≤ 45%, the ERP and action potential duration at 90% repolarization were shorter than in those from patients with LVEF > 45%, by 24% and 18%, respectively. The LVEF and ERP were positively correlated (r = 0.65, P <0.05). The L-type calcium ion current, inward rectifier potassium ion current, and sustained outward ion current were unaffected by LVSD. The transient outward potassium ion current was decreased by 34%, with a positive shift in its activation voltage, and no change in its decay kinetics.
<b>Conclusion:</b>
LVSD in patients in SR is independently associated with a shortening of the atrial cellular ERP, which may be expected to contribute to a predisposition to AF
Benchmarking CPUs and GPUs on embedded platforms for software receiver usage
Smartphones containing multi-core central processing units (CPUs) and powerful many-core graphics processing units (GPUs) bring supercomputing technology into your pocket (or into our embedded devices). This can be exploited to produce power-efficient, customized receivers with flexible correlation schemes and more advanced positioning techniques. For example, promising techniques such as the Direct Position Estimation paradigm or usage of tracking solutions based on particle filtering, seem to be very appealing in challenging environments but are likewise computationally quite demanding. This article sheds some light onto recent embedded processor developments, benchmarks Fast Fourier Transform (FFT) and correlation algorithms on representative embedded platforms and relates the results to the use in GNSS software radios. The use of embedded CPUs for signal tracking seems to be straight forward, but more research is required to fully achieve the nominal peak performance of an embedded GPU for FFT computation. Also the electrical power consumption is measured in certain load levels.Peer ReviewedPostprint (published version
Electrophysiological and arrhythmogenic effects of 5-hydroxytryptamine on human atrial cells are reduced in atrial fibrillation
5-Hydroxytryptamine (5-HT) is proarrhythmic in atrial cells from patients in sinus rhythm (SR) via activation of 5-HT<sub>4</sub> receptors, but its effects in atrial cells from patients with atrial fibrillation (AF) are unknown. The whole-cell perforated patch-clamp technique was used to record L-type Ca<sup>2+</sup> current (<i>I</i><sub>CaL</sub>), action potential duration (APD) and arrhythmic activity at 37 °C in enzymatically isolated atrial cells obtained from patients undergoing cardiac surgery, in SR or with chronic AF. In the AF group, 5-HT (10 μM) produced an increase in <i>I</i><sub>CaL</sub> of 115 ± 21% above control (<i>n</i> = 10 cells, 6 patients) that was significantly smaller than that in the SR group (232 ± 33%; <i>p</i> 0.05; <i>n</i> = 27 cells, 12 patients). Subsequent co-application of isoproterenol (1 μM) caused a further increase in <i>I</i><sub>CaL</sub> in the AF group (by 256 ± 94%) that was greater than that in the SR group (22 ± 6%; p < 0.05). The APD at 50% repolarisation (APD<sub>50</sub>) was prolonged by 14 ± 3 ms by 5-HT in the AF group (<i>n</i> = 37 cells, 14 patients). This was less than that in the SR group (27 ± 4 ms; <i>p</i> < 0.05; <i>n</i> = 58 cells, 24 patients). Arrhythmic activity in response to 5-HT was observed in 22% of cells in the SR group, but none was observed in the AF group (p < 0.05). Atrial fibrillation was associated with reduced effects of 5-HT, but not of isoproterenol, on <i>I</i><sub>CaL</sub> in human atrial cells. This reduced effect on <i>I</i><sub>CaL</sub> was associated with a reduced APD<sub>50</sub> and arrhythmic activity with 5-HT. Thus, the potentially arrhythmogenic influence of 5-HT may be suppressed in AF-remodelled human atrium
Field oriented control dataset of a 3-phase permanent magnet synchronous motor
This paper presents a dataset of a 3-phase Permanent Magnet Synchronous Motor (PMSM) controlled by a Field Oriented Control (FOC) scheme. The data set was generated from a simulated FOC motor control environment developed in Simulink; the model is available in the public GitHub repository1. The dataset includes the motor response to various input signal shapes that are fed to the control scheme to verify the control capabilities when the motor is subjected to real life scenarios and corner conditions. Motor control is one of the most widespread fields in control engineering as it is widely used in machine tools and robots, the FOC scheme is one of the most used control approaches thanks to its performance in speed and torque control, with the drawback of having to handcraft the Proportional-Integrative-Derivative (PID) regulators using Look Up Tables (LUT). The test conditions are designed by setting a motor desired speed. Different input speed variations shapes are proposed as well as extreme scenarios where the linear behaviour of the PID regulator is challenged by applying fast and high magnitude speed variations so that the PID controller is not able to correctly follow the reference. The measured data includes both the outer and inner-loop signals of the FOC, which opens the possibility to develop non-linear control approaches such as Machine Learning (ML) and Neural Networks (NN) with different topologies to replace the linear controllers in the FOC scheme
Post-operative atrial fibrillation is influenced by beta-blocker therapy but not by pre-operative atrial cellular electrophysiology
We investigated whether post-cardiac surgery (CS) new-onset atrial fibrillation (AF) is predicted by pre-CS atrial cellular electrophysiology, and whether the antiarrhythmic effect of beta-blocker therapy may involve pre-CS pharmacological remodeling. Atrial myocytes were obtained from consenting patients in sinus rhythm, just prior to CS. Action potentials and ion currents were recorded using whole-cell patch-clamp technique. Post-CS AF occurred in 53 of 212 patients (25%). Those with post-CS AF were older than those without (67 ± 2 vs 62 ± 1 years, P = 0.005). In cells from patients with post-CS AF, the action potential duration at 50% and 90% repolarization, maximum upstroke velocity, and effective refractory period (ERP) were 13 ± 4 ms, 217 ± 16 ms, 185 ± 10 V/s, and 216 ± 14 ms, respectively (n = 30 cells, 11 patients). Peak L-type Ca2+ current, transient outward and inward rectifier K+ currents, and the sustained outward current were −5.0 ± 0.5, 12.9 ± 2.4, −4.1 ± 0.4, and 9.7 ± 1.0 pA/pF, respectively (13-62 cells, 7-19 patients). None of these values were significantly different in cells from patients without post-CS AF (P > 0.05 for each, 60-279 cells, 29-86 patients), confirmed by multiple and logistic regression. In patients treated >7 days with a beta-blocker pre-CS, the incidence of post-CS AF was lower than in non-beta-blocked patients (13% vs 27%, P = 0.038). Pre-CS beta-blockade was associated with a prolonged pre-CS atrial cellular ERP (P = 0.001), by a similar degree (∼20%) in those with and without post-CS AF. Conclusion: Pre-CS human atrial cellular electrophysiology does not predict post-CS AF. Chronic beta-blocker therapy is associated with a reduced incidence of post-CS AF, unrelated to a pre-CS ERP-prolonging effect of this treatment
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