Search results for "Models"
showing 10 items of 8211 documents
Do large‐scale associations in birds imply biotic interactions or environmental filtering?
2023
Aim There has been a wide interest in the effect of biotic interactions on species' occurrences and abundances at large spatial scales, coupled with a vast development of the statistical methods to study them. Still, evidence for whether the effects of within-trophic-level biotic interactions (e.g. competition and heterospecific attraction) are discernible beyond local scales remains inconsistent. Here, we present a novel hypothesis-testing framework based on joint dynamic species distribution models and functional trait similarity to dissect between environmental filtering and biotic interactions. Location France and Finland. Taxon Birds. Methods We estimated species-to-species association…
Comparison of machine learning and logistic regression as predictive models for adverse maternal and neonatal outcomes of preeclampsia: A retrospecti…
2022
IntroductionPreeclampsia, one of the leading causes of maternal and fetal morbidity and mortality, demands accurate predictive models for the lack of effective treatment. Predictive models based on machine learning algorithms demonstrate promising potential, while there is a controversial discussion about whether machine learning methods should be recommended preferably, compared to traditional statistical models.MethodsWe employed both logistic regression and six machine learning methods as binary predictive models for a dataset containing 733 women diagnosed with preeclampsia. Participants were grouped by four different pregnancy outcomes. After the imputation of missing values, statistic…
Prediction and interpolation of time series by state space models
2015
Artikkeliväitöskirja. Sisältää yhteenveto-osan ja neljä artikkelia. Article dissertation. Contains an introduction part and four articles. A large amount of data collected today is in the form of a time series. In order to make realistic inferences based on time series forecasts, in addition to point predictions, prediction intervals or other measures of uncertainty should be presented. Multiple sources of uncertainty are often ignored due to the complexities involved in accounting them correctly. In this dissertation, some of these problems are reviewed and some new solutions are presented. A state space approach is also advocated for an e cient and exible framework for time series forecas…
Tècniques d'anàlisi genètica: Tema 6
2014
El document forma part dels materials docents programats mitjançant l'ajut del Servei de Política Lingüística de la Universitat de València. Tema 6 de 8, de què consta l'assignatura. Presenta l'ús de marcadors de grups de lligament en espècies model, tant en les que tenen l'entrecreuament limitat a un dels dos sexes com en les que els dos sexes presenten entrecreuament.
Marine reserves : fish life history and ecological traits matter
2010
Copyright by the Ecological Society of America
Students' understanding of mathematical models in three norwegian biology courses
2018
International audience; Development in Biology over the last three decades have greatly increased the need for using mathematics in this field. This has influenced biology students which need to develop mathematical knowledge to be able to work with contemporary biology models, including frameworks that are applicable in analyzing the overwhelming flow of biological data (i.e. Labov, Reid & Yamamoto, 2010). Although a quantitative approach is often used in university biology courses, yet they remain largely qualitative and descriptive (Nelson, et. al., 2009). In Norwegian context, where this study will be conducted, there is an increased awareness towards mathematics from the Departments of…
Estimation of linear errors-in-variable models with error free covariates: a backfitting approach
2008
We present a backfitting algorithm to estimate linear regression mod- els having both error-prone and error-free covariates as predictors. The algorithm assumes that the variance-ratios are known, and it is particulary efficient when several explanatory variables are included. The resulting estimators are shown to be unbiased and to perform well as compared to method-of-moments estimators which are usually employed when the variance ratio is known.
Internal resources as tools to increase the global competition: the Italian wine industry case
2017
Purpose The purpose of this paper is twofold: first, it identifies distinct organizational models in a sample of small and medium enterprises operating in the Sicilian wine industry; and second, it identifies the key factors enabling a superior export success. Design/methodology/approach Internal resources were analyzed theoretically in order to achieve the aims of the study. Subsequently the empirical investigation was carried out administering a questionnaire to a sample of 102 wineries in Sicily, Italy. A cluster analysis was performed in order to group these firms into homogeneous categories. Findings The findings show that success in the international market is more common among winer…
Plasma membrane glycoproteins covalently bound to silica beads as a model for molecular studies of cell-cell interactions in culture.
1987
Abstract In previous studies, we have shown that plasma membrane glycoproteins are of major importance in the density-dependent regulation of growth of normal diploid fibroblasts. Due to the hydrophobic portions of these molecules, functional studies in cell culture are often diffucult to perform and to interpret. Specially, the addition of these molecules in soluble form to cell culture, after depletion of detergents needed for their solubilization, leads to aggregation and internalization. Therefore, we developed a method for the covalent immobilization of the solubilized plasma membrane proteins to derivatized silica beads for further investigations on the molecular nature of the active …
Human Sensorimotor Communication: A Theory of Signaling in Online Social Interactions
2013
Although the importance of communication is recognized in several disciplines, it is rarely studied in the context of online social interactions and joint actions. During online joint actions, language and gesture are often insufficient and humans typically use non-verbal, sensorimotor forms of communication to send coordination signals. For example, when playing volleyball, an athlete can exaggerate her movements to signal her intentions to her teammates (say, a pass to the right) or to feint an adversary. Similarly, a person who is transporting a table together with a co-actor can push the table in a certain direction to signal where and when he intends to place it. Other examples of ``si…