Search results for "Environment"

Entornos virtuales de aprendizaje: modelo ampliado de aceptación de la tecnología

2019

Dentro de la actual renovación de las metodologías docentes, las universidades están impulsando el uso de entornos virtuales de aprendizaje como una herramienta básica en la enseñanza presencial, ya que permite flexibilizar e individualizar la educación. El objetivo del presente trabajo es aportar evidencia empírica sobre la percepción que tienen los alumnos respecto a la mejora en su aprendizaje, al adoptar y utilizar entornos virtuales en la enseñanza presencial, a partir del Modelo de Aceptación de la Tecnología ampliado. La población objeto del estudio son 251 casos de estudiantes de primer grado de la Facultad de Economía de la Universitat de Valencia. Se ha evidenciado empíricamente, …

Análisis edad-periodo-cohorte de la mortalidad por accidentes de tráfico en España

1999

OBJETIVO. Estudiar la evolución de la mortalidad por accidentes de tráfico en España y su posible aplicación a un modelo edad-periodo-cohorte, así como el efecto que pueden tener algunas medidas de seguridad vial seleccionadas. MATERIAL Y MÉTODOS. Se obtuvieron las tasas de mortalidad por accidentes de tráfico y las tasas en intervalos quinquenales de edad para cada sexo, lo que permite su estudio como tasas específicas de edad por cohortes de nacimiento. Para determinar la asociación entre las medidas de seguridad vial seleccionadas y la mortalidad se han construido modelos de regresión de Poisson. RESULTADOS. Se observaron dos ondas evolutivas en la mortalidad por accidentes de tráfico. R…

Interactions, spillovers de connaissance et croissance des économies modernes. Faut-il préférer la globalisation ou la proximité géographique ?

2009

Globalisation and metropolisation in modern economies induce some locational strategies of knowledge based activities towards cities and deeply increase trade and move of ideas across cities. In that context, we study the way knowledge spillovers have influenced the economic growth of 82 European Metropolises over the 1990-2005 period. We model knowledge spillovers across cities according to three specific interaction patterns depending either on geography or on global advanced services or thought a combination of these patterns. We show that the mixed pattern matters the best for economic growth of cities in Europe.

Chemical-Based Methodologies to Extend the Shelf Life of Fresh Fish—A Review

2021

Due to its characteristics, fresh fish is a highly perishable food with a very short shelf-life under refrigeration. Several methods have been introduced to slow down its deterioration, such as by means of oxygen depletion of the food package (vacuum packaging), or by changing the natural atmosphere that is in contact with the fresh fish (modified atmosphere packaging), or by the use of chemicals generally recognized as safe: such compounds can be directly applied (by dipping or spraying) or incorporated into packaging materials and slowly migrate to the product, exerting a hurdle effect against microbial development and lipid oxidation (active packaging). This review aims to cover the most…

Simafield : Un logiciel de modélisation spatiale de scènes agronomiques

2013

Environmental measures lead farmers to use more and more decision support tools to reduce their chemical inputs without losing yield. Imaging system based on crop/weed discrimination algorithms have been developed to detect weeds in field and allow a site specific spraying. These algorithms needs to be thoroughly evaluated before considering a public release and current evaluation are based on real images and are very tedious. SimAField is a software that aims at modeling agronomic fields with crop and weeds and simulate the picture taking process to replace ground truth and allow an automated evaluation of crop/weed discrimination algorithms.

Impact du climat sur la santé : modélisation régionale des poussières pour les épidémies de méningites au Sahel.

2014

6 pages; International audience; Les épidémies des méningites bactériennes constituent encore à l’heure actuelle un problème de santé publiquemajeur en Afrique de l’Ouest. Chaque année, au coeur de la saison sèche (de janvier à mars), 25 000 à 250 000 cas sontenregistrés par l’Organisation Mondiale de la Santé (OMS) dans la zone latitudinale 10-15°N, plus communément appelée« ceinture de la méningite ». L’importance des facteurs sociétaux dans l’expansion des épidémies est indéniable. Cependant,une série d’études récentes a permis de mettre en lumière le rôle important du climat. Ainsi, l’intensité des épidémies sembleliée à des conditions de circulation atmosphérique spécifiques quelques m…

Molecular approaches to study microbial mechanisms involved in pesticide biodegradation: atrazine as a case study

2006

Sediment quality of the ecoregion Engure, Gulf of Riga, assessed by using ecotoxicity tests and biomarker responses

2014

Pētījuma mērķis bija novērtēt Engures ekoreģiona (Rīgas līča rietumu piekrastes) sedimentu kvalitāti, izmantojot sedimentu ekotoksicitātes testus. Lai noteiktu bioloģiskās atbildes reakcijas uz dažāda veida stresoriem, kā testorganismi pielietotas sānpeldes Monoporeia affinis and Pontogammarus robustoides, un izvēlēti biomarķieri (AChE, GST, GR, CAT, MT), kas noteikti gliemenēs Macoma balthica. Engures ekoreģionu varētu uzskatīt par nepiesārņotu rajonu, jo tā sedimentus raksturo salīdzinoši zemas smago metālu koncentrācijas. Engures ekoreģiona sedimentu ekotoksicitātes testu rezultāti neuzrādīja statistiski būtisku (>20% mirstība) toksisko efektu. Testorganismu izdzīvotība bija robežās no 8…

Concentrations of metallothionein in the bivalve molluscsAnodonta spp.andUnio spp.from Latvian lakes with different anthropogenic pressure

2013

Concentrations of metallothioneins (MT) were analysed in bivalve molluscs Anodonta spp. and Unio spp. from 6 lakes and watercourses of Latvia with different anthropogenic pressure. The aim of the study was to find the relationship between MT in molluscs and concentrations of heavy metals in sediments. Unio spp. and Anodonta spp. showed no significant differences in the concentrations of MT. High concentrations of heavy metals (Cd, Pb, Hg, Cu, Zn) were detected in the deepest parts of polluted water bodies, however their concentrations significantly decreased in near shore sediments inhabited by molluscs. Only Zn tends to accumulate in the molluscs, reaching 2-7 times higher concentrations i…

Ambrosia trifida L. in France: current distribution and ecological knowledge. Towards an eradication of the species?

2014

National audience; Giant ragweed (Ambrosia trifida L.) is an annual plant belonging to Asteraceae, originating from North America. It was introduced in France in the early twentieth century. Originally described as a ruderal plant, Ambrosia trifida was recently reported in agricultural areas (maize and soybean) in the region Midi-Pyrénées. Beyond the potential public health issue, this species is a major invasive weed in North America, its native area. That is why a question arises about the future trend of the species in France. Can we expect a low ability of the species to adapt the French habitats and land-uses, with a low probability of naturalization? Viceversa, should we consider lead…