3,017 research outputs found
Observability and Synchronization of Neuron Models
Observability is the property that enables to distinguish two different
locations in -dimensional state space from a reduced number of measured
variables, usually just one. In high-dimensional systems it is therefore
important to make sure that the variable recorded to perform the analysis
conveys good observability of the system dynamics. In the case of networks
composed of neuron models, the observability of the network depends
nontrivially on the observability of the node dynamics and on the topology of
the network. The aim of this paper is twofold. First, a study of observability
is conducted using four well-known neuron models by computing three different
observability coefficients. This not only clarifies observability properties of
the models but also shows the limitations of applicability of each type of
coefficients in the context of such models. Second, a multivariate singular
spectrum analysis (M-SSA) is performed to detect phase synchronization in
networks composed by neuron models. This tool, to the best of the authors'
knowledge has not been used in the context of networks of neuron models. It is
shown that it is possible to detect phase synchronization i)~without having to
measure all the state variables, but only one from each node, and ii)~without
having to estimate the phase
Short communication: Genetic parameters for post-weaning visual scores and reproductive traits in Suffolk sheep
         The aim of this study was to estimate the coefficients of heritability and genetic correlations among visual scores (conformation, CPW; precocity, PPW; musculature, MPW) and reproductive traits: age at first lambing (AFL) and scrotal circumference (SC) evaluated at 180 days of age in Suffolk lambs. In the statistical model only the additive genetic effect was considered as random effect. The heritability estimates by univariate analyses for CPW, PPW, MPW, AFL and SC were 0.08, 0.12, 0.09, 0.20 and 0.22, respectively. The genetic correlations among AFL and CPW, PPW, MPW were -0.26, 0.19, and 0.08, respectively. The genetic correlation among SC and CPW, PPW, MPW were, respectively, 0.54, 0.88 and 0.86, and between AFL and SC was 0.26. The direct selection for conformation, precocity and musculature at 180 days of age and age at first lambing will provide slow genetic progress due to low heritability estimates. It is possible to obtain genetic gain in sexual precocity through selection on scrotal circumference in Suffolk rams. The favorable genetic correlation among visual scores and SC and between CPW and AFL, indicated the possibility to gain in genetic progress for reproductive traits through indirect selection of the visual scores in Suffolk sheep
Perguntamos: qual o diagnóstico?
Centro de Medicina Diagnóstica FleuryUniversidade Federal de São Paulo (UNIFESP)University of British ColumbiaUNIFESPSciEL
Migration, communities-on-the-move and international innovation networks: An empirical analysis of Spanish regions
This paper investigates the impact of migration on innovation networks between regions and foreign countries. We posit that immigrants (emigrants) act as a transnational knowledge bridge between the host (home) regions and their origin (destination) countries, thus facilitating their co-inventorship networks. We also argue that the social capital of both the hosting and the moving communities reinforces such a bridging role, along with language commonality and migrants’ human capital. Focusing on Spain, as a country that hosted an intense process of migration over the past two decades, we combine patent data with national data on residents and electors abroad and we apply a gravity model to the co-inventorship between Spanish provinces (NUTS3 regions) and a number of foreign countries. Both immigrants and emigrants affect the kind of innovation networking at stake. The social capital of both the moving and the hosting communities actually moderate this impact in a positive way. The effect of migration is stronger for more skilled migrants and with respect to non-Spanish speaking countries, pointing to a language-bridging role of migrants. Policy implications are drawn accordingly
Regime-Dependent Sovereign Risk Pricing During the Euro Crisis
Previous work has documented a greater sensitivity of long-term government bond yields to fundamentals in euro area peripheral countries during the euro crisis, but we know little about the driver(s) of regime switches. Our estimates based on a panel smooth threshold regression model quantify and explain them: (1) investors have penalized a deterioration of fundamentals more strongly from 2010 to 2012; (2) the higher the bank credit risk, measured with the premium on credit derivatives, the higher the extra premium on fundamentals; (3) after ECB President Draghi’s speech in July 2012, it took 1 year to restore the noncrisis regime and suppress the extra premiu
Genetic markers in the study of Anisakis typica (Diesing, 1860): larval identification and genetic relationships with other species of Anisakis Dujardin, 1845 (Nematoda: Anisakidae)
Genetic variation at 21 gene-enzyme systems was studied in a sample of an adult population of Anisakis typica
(Diesing, 1860) recovered in the dolphin Sotalia fluviatilis from the Atlantic coast of Brazil. The characteristic
alleles, detected in this population, made it possible to identify as A. typica, Anisakis larvae with a Type I morphol ogy (sensu Berland, 1961) from various fishes: Thunnus thynnus and Auxis thazard from Brazil waters, Trachurus
picturatus and Scomber japonicus from Madeiran waters, Scomberomorus commerson, Euthynnus affinis, Sarda
orientalis and Coryphaena hippurus from the Somali coast of the Indian Ocean, and Merluccius merluccius from
the Eastern Mediterranean. Characteristic allozymes are given for the identification, at any life-stage and in both
sexes, of A. typica and the other Anisakis species so far studied genetically. The distribution of A. typica in warmer
temperate and tropical waters is confirmed; the definitive hosts so far identified for this species belong to delphinids,
phocoenids and pontoporids. The present findings represent the first established records of intermediate/paratenic
hosts of A. typica and extend its range to Somali waters of the Indian Ocean and to the Eastern Mediterranean
Sea. A remarkable genetic homogeneity was observed in larval and adult samples of A. typica despite their
different geographical origin; interpopulation genetic distances were low, ranging from DNei = 0.004 (Eastern
Mediterranean versus Somali) to DNei = 0.010 (Brazilian versus Somali). Accordingly, indirect estimates of gene
flow gave a rather high average value of Nm = 6.00. Genetic divergence of A. typica was, on average, DNei = 1.12
from the members of the A. simplex complex (A. simplex s.s, A. pegreffii, A. simplex C) and DNei = 1.41 from
A. ziphidarum, which all share Type I larvae; higher values were found from both A. physeteris (DNei = 2.77) and A. brevispiculata (DNei = 2.52), which have Type II larvae (sensu Berland, 1961). Genetic relationships
among these species are shown using multidimensional scaling ordination (MDS). The genus Anisakis appears to
be phylogenetically heterogeneous and includes two distinct groups of species, which are morphologically and
genetically differentiated.info:eu-repo/semantics/publishedVersio
One Hundred Fourth Annual Report of the Town Officers Plainville, Massachusetts for the Year Ending June 30, 2008
The concept of observability of linear systems initiated with Kalman in the
mid 1950s. Roughly a decade later, the observability of nonlinear systems
appeared. By such definitions a system is either observable or not. Continuous
measures of observability for linear systems were proposed in the 1970s and two
decades ago were adapted to deal with nonlinear dynamical systems. Related
topics developed either independently or as a consequence of these.
Observability has been recognized as an important feature to study complex
networks, but as for dynamical systems in the beginning the focus has been on
determining conditions for a network to be observable. In this relatively new
field previous and new results on observability merge either producing new
terminology or using terms, with well established meaning in other fields, to
refer to new concepts. Motivated by the fact that twenty years have passed
since some of these concepts were introduced in the field of nonlinear
dynamics, in this paper (i)~various aspects of observability will be reviewed,
and (ii)~it will be discussed in which ways networks could be ranked in terms
of observability. The aim is to make a clear distinction between concepts and
to understand what does each one contribute to the analysis and monitoring of
networks. Some of the main ideas are illustrated with simulations
Une plateforme pour l'acquisition, la maintenance et la validation de ressources lexicales
International audienceNous présentons une plateforme de développement de lexique offrant une base lexicale accompagnée d'un certain nombre d'outils de maintenance et d'utilisation. Cette base, qui comporte aujourd'hui 440.000 formes du Français contemporain, est destinée à être diffusée et remise à jour régulièrement. Nous exposons d'abord les outils et les techniques employées pour sa constitution et son enrichissement, notamment la technique de calcul des fréquences lexicales par catégorie morphosyntaxique. Nous décrivons ensuite différentes approches pour constituer un sous-lexique de taille réduite, dont la particularité est de couvrir plus de 90% de l'usage. Un tel lexique noyau offre en outre la possibilité d'être réellement complété manuellement avec des informations sémantiques, de valence, pragmatiques etc
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