Search results for " Models"

Simulation model comparing the hydroperiod of temporary ponds with different shapes

2010

A model of the water dynamics for shallow, small and temporary Mediterranean ponds has been developed taking into account the annual patterns of rainfall and potential evaporation, pond parameters (pond area, depth and shape) and watershed parameters (watershed area and saturated water content of the soil). This model predicts the amount of water retained in the pond in real time and therefore, when a pond is going to dry out. It is then possible to calculate how much water will remain in the pond after raining or the number of days per year that the pond is going to be dry. Analyses have been performed for different shapes of ponds and sensitivity of the state variables, at different value…

Invasion biology in non‐free‐living species: interactions between abiotic (climatic) and biotic (host availability) factors in geographical space in …

2013

In invasion processes, both abiotic and biotic factors are considered essential, but the latter are usually disregarded when modeling the potential spread of exotic species. In the framework of set theory, interactions between biotic (B), abiotic (A), and movement-related (M) factors in the geographical space can be hypothesized with BAM diagrams and tested using ecological niche models (ENMs) to estimate A and B areas. The main aim of our survey was to evaluate the interactions between abiotic (climatic) and biotic (host availability) factors in geographical space for exotic symbionts (i.e., non-free-living species), using ENM techniques combined with a BAM framework and using exotic Entoc…

Ocean acidification through the lens of ecological theory

2015

© 2015 by the Ecological Society of America. Ocean acidification, chemical changes to the carbonate system of seawater, is emerging as a key environmental challenge accompanying global warming and other humaninduced perturbations. Considerable research seeks to define the scope and character of potential outcomes from this phenomenon, but a crucial impediment persists. Ecological theory, despite its power and utility, has been only peripherally applied to the problem. Here we sketch in broad strokes several areas where fundamental principles of ecology have the capacity to generate insight into ocean acidification's consequences. We focus on conceptual models that, when considered in the co…

Introduction

1998

Climatic Characterization and Phenology of Local Peach Genotypes in the Udzungwa Uplands of Tanzania

2014

The phenology of two local peach genotypes was studied to verify whether peaches can be produced in the Tanzanian uplands. Observations were conducted on trees of one early- and one late-ripening peach genotype in 2010 and 2011. Temperature trends were reconstructed and three chilling estimation models were tested. The two peach genotypes differed for timing of flower and leaf bud-break. Common symptoms of insufficient chilling (presence of numerous stages at a specific date and about 20% of undeveloped flower buds) were observed in the late genotype. Both Utah and Dynamic models indicated low chilling accumulation, lower than the Mean Temperature model in most cases. This is inconsistent w…

Valoració de l’Avaluació en Competències a través de models d’elecció discreta

2017

La implantació dels nous mètodes d’ensenyament, sota el marc establert per l’Espai Europeu d’Educació  Superior (EEES), suposa un canvi en l’organització de la forma d’ensenyar i aprendre, centrat en la formació per competències. En termes d’avaluació, la nova forma d’ensenyament implica el pas d’un sistema d’avaluació única a un sistema d’avaluació contínua, en el qual l’estudiant participa activament en el procés d’aprenentatge i en la consecució no només dels objectius establerts per a cada assignatura, sinó també en l’adquisició d’habilitats i destreses més generals i de caràcter transversal. L’objectiu d’aquesta comunicació és presentar una anàlisi de l’impacte sobre el resultat final …

Does Tourism Consumption Behaviour Mirror Differences in Living Standards?

2016

Based on the theoretical foundation of well-being measurement, the study explores differences in living standards by analysing the distribution of tourism expenditure. A mixture of regression models is used to explore the heterogeneity in tourism consumption by identifying groups of families with similar tourism consumption behaviour as a function of certain socio-demographic and economic factors. The empirical analysis, performed on Italian expenditure data, suggests that there are three different patterns of consumption behaviour conditional to the socio-demographic and economic covariates in the tourism market and that differences in tourism consumption between groups of households mirro…

Contribution of the Economic Crisis to the Risk Increase of Poor Mental Health in a Region of Spain

2018

Previous research suggests that the economic crisis can affect mental health. The purpose of this study was to analyse the association of risk of poor mental health with various socioeconomic, demographic, health, quality of life, and social support variables

Resisting the extortion racket: an empirical analysis

2018

While the contributions on the organized crime and Mafia environments are many, there is a lack of empirical evidence on the firm’s decision to resist to extortion. Our case study is based on Addiopizzo, an NGO that, from 2004, invites firms to refuse requests from the local Mafia and to join a public list of “non-payers”. The research is based on a dataset obtained linking the current administrative archives maintained by the chambers of commerce and the list updated by the NGO. The objective of this paper is twofold: first, to gather sound data on the characteristics of the Addiopizzo joiners; second to model the probability to join Addiopizzo by a two-level logistic regression model. We …

Unbundling technology adoption and tfp at the firm level. Do intangibles matter?

2012

We use a panel of European firms to investigate the relationship between intangible assets and productivity. We distinguish between total factor productivity (tfp) and technology adoption, whereas standard estimations consider only a notion of productivity that conflates the two effects. Although we are unable to address simultaneity, we allow for the existence of multiple technologies within sectors through a mixture model approach. We find that intangible assets have nonnegligible effects that both push firms toward better technologies (technology adoption effects) and allow for more efficient exploitation of a given technology (tfp effects).