1,708 research outputs found

    Gaston Bachelard and Contemporary Philosophy

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    This special issue aims to redress the balance and to open up Gaston Bachelard's work beyond a small in-crowd of experts and aficionado’s in France. It aims to stimulate the discovery of new and understudied aspects of Bachelard’s work, including aspects of the intellectual milieu he was working in. Fortunately, for this purpose we were able to rely both on renowned Bachelard specialists, such as Hans-Jörg Rheinberg-er, Cristina Chimisso and Dominique Lecourt, as well as on a number of younger scholars who are discovering their work in a different intellectual context. At the same time we also want to reassess the value of this oeuvre, which also entails examining the reasons and causes of the relative neglect of Bachelard’s work in recent times. Has it exhausted its possibilities? Does it have intrinsic limitations that have contributed to the eclipse, as some influential, mainly French, philoso-phers have more or less explicitly suggested

    Marginal analysis of longitudinal count data in long sequences: Methods and applications to a driving study

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    Most of the available methods for longitudinal data analysis are designed and validated for the situation where the number of subjects is large and the number of observations per subject is relatively small. Motivated by the Naturalistic Teenage Driving Study (NTDS), which represents the exact opposite situation, we examine standard and propose new methodology for marginal analysis of longitudinal count data in a small number of very long sequences. We consider standard methods based on generalized estimating equations, under working independence or an appropriate correlation structure, and find them unsatisfactory for dealing with time-dependent covariates when the counts are low. For this situation, we explore a within-cluster resampling (WCR) approach that involves repeated analyses of random subsamples with a final analysis that synthesizes results across subsamples. This leads to a novel WCR method which operates on separated blocks within subjects and which performs better than all of the previously considered methods. The methods are applied to the NTDS data and evaluated in simulation experiments mimicking the NTDS.Comment: Published in at http://dx.doi.org/10.1214/11-AOAS507 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

    Los desafíos de la seguridad energética mundial

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    Study of DNA mediated gene transfer in mouse cells

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    Microwave characterization of slotline on high resistivity silicon for antenna feed network

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    Conventional silicon wafers have low resistivity and consequently unacceptably high value of dielectric attenuation constant. Microwave circuits for phased array antenna systems fabricated on these wafers therefore have low efficiency. By choosing a silicon substrate with sufficiently high resistivity it is possible to make the dielectric attenuation constant of the interconnecting microwave transmission lines approach those of GaAs or InP. In order for this to be possible, the transmission lines must be characterized. In this presentation, the effective dielectric constant (epsilon sub eff) and attenuation constant (alpha) of a slotline on high resistivity (5000 to 10 000 ohm-cm) silicon wafer will be discussed. The epsilon sub eff and alpha are determined from the measured resonant frequencies and the corresponding insertion loss of a slotline ring resonator. The results for slotline will be compared with microstrip line and coplanar waveguide

    Rodents of Unusual Sperm

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    Interactive ant colony optimization (iACO) for early lifecycle software design

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    Finding good designs in the early stages of the software development lifecycle is a demanding multi-objective problem that is crucial to success. Previously, both interactive and non-interactive techniques based on evolutionary algorithms (EAs) have been successfully applied to assist the designer. However, recently ant colony optimization was shown to outperform EAs at optimising quantitative measures of software designs with a limited computational budget. In this paper, we propose a novel interactive ACO (iACO) approach, in which the search is steered jointly by an adaptive model that combines subjective and objective measures. Results show that iACO is speedy, responsive and effective in enabling interactive, dynamic multi-objective search. Indeed, study participants rate the iACO search experience as compelling. Moreover, inspection of the learned model facilitates understanding of factors affecting users' judgements, such as the interplay between a design's elegance and the interdependencies between its components. © 2014 Springer Science+Business Media New York

    Sperm Pairing and Measures of Efficiency in Planar Swimming Models

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    Sperm of certain species engage in cooperative swimming behaviors which result in differences in velocity and efficiency of swimming, as well as ability to effectively fertilize the egg. In particular, Monodelphis domestica is a species of opossum whose sperm often swim cooperatively as a pair, with heads fused together. In order to understand the empirical effects of cooperative swimming behaviors, we propose a simple preferred-curvature-based model to model individual and paired sperm using the method of regularized Stokeslets to model the viscous fluid environment. The effects of swimming freely versus paired swimming, phase relationship, and the angle at which sperm heads are fused are investigated. Results are consistent with previous modeling work for free swimmers. Paired (fused) swimming results also compare well with experimental work, and provide evidence for optimal geometrical configurations. This indicates that there may be a fluid mechanical advantage to such cooperative motility behaviors in sperm swimming

    Cyclical production planning without losing flexibility

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    On the ground electronic states of copper silicide and its ions

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    The low-lying electronic states of SiCu, SiCu^+, and SiCu^− have been studied using a variety of high-level ab initio techniques. As expected on the basis of simple orbital occupancy and bond forming for Si(s^2p^2)+Cu(s^1) species, ^2Π_r, ^1Σ^+, and ^3Σ^− states were found to be the ground electronic states for SiCu, SiCu^+, and SiCu^−, respectively; the ^2Π_r state is not that suggested in most recent experimental studies. All of these molecules were found to be quite strongly bound although the bond lengths, bond energies, and harmonic frequencies vary slightly among them, as a result of the nonbonding character of the 2π-MO (molecular orbital) [composed almost entirely of the Si 3p-AO (atomic orbital)], the occupation of which varies from 0 to 2 within the ^1Σ^+, ^2Π_r, and ^3Σ^− series. The neutral SiCu is found to have bound excited electronic states of ^4Σ^−, ^2Δ, ^2Σ^+, and ^2Π_i symmetry lying 0.5, 1.2, 1.8, and 3.2 eV above the ^2Π_r ground state. It is possible but not yet certain that the ^2Π_i state is, in fact, the “B state” observed in the recent experimental studies by Scherer, Paul, Collier, and Saykally
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