Search results for " Probability"
showing 10 items of 2176 documents
Resident and transient dynamics, site fidelity and survival in wintering Blackcaps Sylvia atricapilla: evidence from capture-recapture analyses
2007
In their winter quarters, migrant birds may either remain within a small area (resident strategy) or move frequently over a large area looking for locally abundant food (transient strategy). It has been suggested that both strategies could simultaneously occur in the same population. We used time-since-marking capture‐recapture models to infer the coexistence of these two behavioural strategies (transient and resident) among wintering Blackcaps Sylvia atricapilla using weekly recapture data over a 7-year period. A related question is whether Blackcaps, if surviving to the next winter, always return to the same wintering area, so we also used this approach to analyse winter site fidelity and…
The use of Markovian metapopulation models: Reducing the dimensionality of transition matrices by self-organizing Kohonen networks
2006
Abstract Markovian population models are used in conservation biology to find an accurate estimate of a population's extinction probability. Such models require handling of large transition matrices and calculations are thus extremely time-consuming when large populations have to be studied. To accomplish these problems, some authors have suggested to group together several states/sizes of the population. Unfortunately, this so-called binning frequently results in errors in estimates obtained. The main problem with binning is that it assumes that grouped states behave nearly identical with respect to the underlying stochastic population process and that so far binning methods implicitly vio…
Estimating Polling Accuracy in Multiparty Elections Using Surveybias
2016
Any rigorous discussion of bias in opinion surveys requires a scalar measure of survey accuracy. Martin, Traugott, and Kennedy (2005, Public Opinion Quarterly 69: 342-369) propose such a measure A for the two-party case, and Arzheimer and Evans (2014, Political Analysis 22: 31-44) demonstrate how measures A'i, B, and Bw for the more common multiparty case can be derived. We describe the commands surveybias, surveybiasi, and surveybiasseries, which enable the fast computation of these binomial and multinomial measures of bias in opinion surveys. While the examples are based on pre-election surveys, the methodology applies to any multinomial variable whose true distribution in the population…
Application of a Bayesian Spatiotemporal Surveillance Method to NYC Syndromic Data
2014
Incorporating prior knowledge (e.g., the spatial distribution of zip codes and background population effects) into a model using Bayesian methods could potentially improve outbreak detection. We adapted a previously described Bayesian model-based spatiotemporal surveillance technique to daily respiratory syndrome counts in NYC Emergency Department data in 2009, the year of the H1N1 influenza pandemic. Citywide, 56 alarms were produced across 15 zip codes, all during days of elevated respiratory visits. Future work includes evaluating our choice of baseline length, considering other alarm thresholds, and conducting a formal evaluation of the method across five syndromes in NYC.
Bayesian reanalysis of a quantitative trait locus accounting for multiple environments by scaling in broilers1
2006
A Bayesian method was developed to handle QTL analyses of multiple experimental data of outbred populations with heterogeneity of variance between sexes for all random effects. The method employed a scaled reduced animal model with random polygenic and QTL allelic effects. A parsimonious model specification was applied by choosing assumptions regarding the covariance structure to limit the number of parameters to estimate. Markov chain Monte Carlo algorithms were applied to obtain marginal posterior densities. Simulation demonstrated that joint analysis of multiple environments is more powerful than separate single trait analyses of each environment. Measurements on broiler BW obtained from…
<em>Grid</em> poblacional 2011 para España. Evaluación metodológica de diversas posibilidades de elaboración
2017
Este trabajo presenta una evaluación, desde el punto de vista del usuario, de la malla regular (grid) de población, con resolución de 1 km2 , que el Instituto Nacional de Estadística (INE) ha hecho pública a partir de los resultados del Censo de Población y Viviendas 2011. Esta forma de difusión de resultados resulta muy novedosa y ofrece un gran valor analítico. Por primera vez esta información sobre la distribución espacial de la población se ha generado desde abajo (bottom-up) para el conjunto de España, es decir, a partir del conocimiento de las coordenadas de cada hogar, considerando como tales las del edificio donde reside. La disponibilidad de otra grid con idéntica resolución, elabo…
Steering Distillation Processes through Zeno dynamics
2005
A quantum system in interaction with a repeatedly measured one undergoes a nonunitary time evolution and is pushed into a subspace substantially determined by the two-system coupling. The possibility of suitably modifying such an evolution through quantum Zeno dynamics (i.e., the generalized quantum Zeno effect) addressing the system toward an a priori decided target subspace is illustrated. Applications and their possible realizations in the context of trapped ions are also discussed.
Food Security Is None Of Your Business? Food Supply Chain Management In Support Of A Sustainable Food System
2017
Food security is the principal outcome of any given food system and it can be defined in terms of a sustainable food system where the core goal is to feed everyone sustainably, equitably and healthily. A sustainable food system addresses needs for availability, affordability and accessibility, is diverse, ecologically-sound and resilient, and builds the capabilities and skills necessary for future generations. This paper identifies the essential elements of food supply chain management in support of a sustainable food system, which ultimately enhances food security. The existing food supply chain and food system literature is synthesized in order to study the correspondence between public i…
Determination of intrinsic scatter in lifetimes of carbon fibre epoxy pressure vessels in view of defining fundamental safety factors
2011
International audience
Inherent information in the prices of options
2018
Esta tesis tiene como objetivo analizar el contenido informacional de los precios observados de las opciones. En este caso particular, teniendo diferentes opciones sobre el mismo subyacente y con la misma fecha de vencimiento, podemos obtener información sobre la función de densidad neutral al riesgo (RND). Éstas son las densidades con las que los agentes valoran los activos derivados, y en definitiva cómo ponen precio a unidades de consumo en diferentes estados de la naturaleza futuros. Esta información implícita en el precio de las opciones es considerada información forward-looking (con miras al futuro). Esta tesis consta de tres capítulos enfocados a analizar diferentes aspectos de los …