1000 resultados para Kyllästinen, Esa
Resumo:
Modeling ecological niches of species is a promising approach for predicting the geographic potential of invasive species in new environments. Argentine ants (Linepithema humile) rank among the most successful invasive species: native to South America, they have invaded broad areas worldwide. Despite their widespread success, little is known about what makes an area susceptible - or not - to invasion. Here, we use a genetic algorithm approach to ecological niche modeling based on high-resolution remote-sensing data to examine the roles of niche similarity and difference in predicting invasions by this species. Our comparisons support a picture of general conservatism of the species' ecological characteristics, in spite of distinct geographic and community contexts
Resumo:
Mediterranean endemic freshwater fish are among the most threatened biota in the world. Distinguishing the role of different extinction drivers and their potential interactions is crucial for achieving conservation goals. While some authors argue that invasive species are a main driver of native species declines, others see their proliferation as a co-occurring process to biodiversity loss driven by habitat degradation. It is difficult to discern between the two potential causes given that few invaded ecosystems are free from habitat degradation, and that both factors may interact in different ways. Here we analyze the relative importance of habitat degradation and invasive species in the decline of native fish assemblages in the Guadiana River basin (southwestern Iberian Peninsula) using an information theoretic approach to evaluate interaction pathways between invasive species and habitat degradation (structural equation modeling, SEM). We also tested the possible changes in the functional relationships between invasive and native species, measured as the per capita effect of invasive species, using ANCOVA. We found that the abundance of invasive species was the best single predictor of natives’ decline and had the highest Akaike weight among the set of predictor variables examined. Habitat degradation neither played an active role nor influenced the per capita effect of invasive species on natives. Our analyses indicated that downstream reaches and areas close to reservoirs had the most invaded fish assemblages, independently of their habitat degradation status. The proliferation of invasive species poses a strong threat to the persistence of native assemblages in highly fluctuating environments. Therefore, conservation efforts to reduce native freshwater fish diversity loss in Mediterranean rivers should focus on mitigating the effect of invasive species and preventing future invasions
Resumo:
Fungi and bacteria are key agents in plant litter decomposition in freshwater ecosystems. However, the specific roles of these two groups and their interactions during the decomposition process are unclear. We compared the growth and patterns of degradativeenzymes expressed by communities of bacteria and fungi grown separately and in coexistence on Phragmites leaves. The two groups displayed both synergistic and antagonistic interactions. Bacteria grew better together with fungi than alone. In addition, there was a negative effect of bacteria on fungi, which appeared to be caused by suppression of fungal growth and biomass accrual rather than specifically affecting enzyme activity. Fungi growing alone had a high capacity for the decomposition of plant polymers such as lignin, cellulose, and hemicellulose. In contrast, enzyme activities were in general low when bacteria grew alone, and the activity of key enzymes in the degradation of lignin and cellulose (phenol oxidase and cellobiohydrolase) was undetectable in the bacteria-only treatment. Still, biomass-specific activities of most enzymes were higher in bacteria than in fungi. The low total activity and growth of bacteria in the absence of fungi in spite of apparent high enzymatic efficiency during the degradation of many substrates suggest that fungi provide the bacteria with resources that the bacteria were not able to acquire on their own, most probably intermediate decomposition products released by fungi that could be used by bacteria
Resumo:
Most ecosystems undergo substantial variation over the seasons, ranging from changes in abiotic features, such as temperature, light and precipitation, to changes in species abundance and composition. How seasonality varies along latitudinal gradients is not well known in freshwater ecosystems, despite being very important in predicting the effects of climate change and in helping to advance ecological understanding. Stream temperature is often well correlated with air temperature and influences many ecosystem features such as growth and metabolism of most aquatic organisms. We evaluated the degree of seasonality in ten river mouths along a latitudinal gradient for a set of variables, ranging from air and water temperatures, to physical and chemical properties of water and growth of an invasive fish species (eastern mosquitofish, Gambusia holbrooki ). Our results show that although most of the variation in air temperature was explained by latitude and season, this was not the case for water features, including temperature, in lowland Mediterranean streams, which depended less on season and much more on local factors. Similarly, although there was evidence of latitude-dependent seasonality in fish growth, the relationship was nonlinear and weak and the significant latitudinal differences in growth rates observed during winter were compensated later in the year and did not result in overall differences in size and growth. Our results suggest that although latitudinal differences in air temperature cascade through properties of freshwater ecosystems, local factors and complex interactions often override the water temperature variation with latitude and might therefore hinder projections of species distribution models and effects of climate change
Resumo:
International texts recognise the buyer's right to the repair or replacement if the goods do not conform with the contract, and at the same time, establish exceptions to their application and certain rules of protection for the seller (Art. 46 CISG, Art. 7.2.3 UNIDROIT Principles of International Commercial Contracts, Art.9:102 PECL and Arts. 4:202 y 4:204 (1) PEL S). This approach is a result of a compromise between civil law systems and the common law and it has been widely extended to the regulation of consumer sales over the last decade (Art. 3.3 of the Directive 1999/44/CE, Art. III.-3:302 DCFR, Art. 26 of the proposal for a Directive on Consumer Rights). These norms regulate the different ways of requiring the fulfilment of a contractual obligation from a new paradigm which has little to do with a need to protect the weak consumer which governed the origins of consumer policy in the European Community. Now the idea of the consumer who shall behave economically efficiently prevails in Art. 3.3 of the Directive 1999/44/CE, a norm which is clearly influenced by the international texts and whose transposing into the national legislation of Member States has created important problems for traditional dogmas. In this sense there are still some unclear issues, such as the possibility of replacing in sales of goods of specific nature or second-hand goods, some aspects on the exercise of repair and replacement, and, even, their use as primary remedies rather than a reduction in price or a rescission of the contract. With regard to this, in England the possibility of offering the consumer free choice between these measures if the goods do not conform with the contract has been raised. This is far from the principle of pacta sunt servanda and is clearly contrary to the economic approach of the proposal for a Directive on Consumer Rights. Up to now Spain has limited itself to implementing Art. 3.3 Directive 1999/44/CE into its legal system in almost literal terms and the case law on the issue has completely turned out to be insufficient. By contrast with Germany, the Spanish legislator has not extended the application of the rules of repair and replacement of Directive 1999/44/CE to nonconsumer sales, even though two draft bill proposals along these lines presented by the General Commission for Codifying (“Comisión General de Codificación”), the last one being in January, 2009
Homogenization Dynamics and Introduction Routes of Invasive Freshwater Fish in the Iberian Peninsula
Resumo:
Nonnative invasive species are one of the main global threats to biodiversity. The understanding of the traits characterizing successful invaders and invasion-prone ecosystems is increasing, but our predictive ability is still limited. Quantitative information on biotic homogenization and particularly its temporal dynamics is even scarcer. We used freshwater fish distribution data in the Iberian Peninsula in four periods (before human intervention, 1991, 1995, and 2001) to assess the temporal dynamics of biotic homogenization among river basins. The percentage of introduced species among fish faunas has increased in recent times (from 41.8% in 1991 to 52.5% in 2001), leading to a clear increase in the similarity of community composition among basins. The mean Jaccard's index increase (a measure of biotic homogenization) from the pristine situation to the present (17.1%) was similar to that for Californian fish but higher than for other studies. However, biotic homogenization was found to be a temporally dynamic process, with finer temporal grain analyses detecting transient stages of biotic differentiation. Introduced species assemblages were spatially structured along a latitudinal gradient in the Iberian Peninsula, with species related to sport fishing being characteristic of northern basins. Although the comparison of fish distributions in the Iberian Peninsula and France showed significant and generalized biotic homogenization, nonnative assemblages of northeastern Iberian basins were more similar to those of France than to those of the rest of the Iberian Peninsula, indicating a main introduction route. Species introduced to the Iberian Peninsula tended to be mainly piscivores or widely introduced species that previously had been introduced to France. Our results indicate that the simultaneous analysis of the spatial distribution of introduced assemblages (excluding native species that reflect other biogeographical patterns) and their specific traits can be an effective tool to detect introduction and invasion routes and to predict future invaders from donor regions
Resumo:
El presente documento tiene como objetivo analizar los riesgos a los que se ven sometidos los trabajadores de un pequeño taller mecánico. Para ello se planificó una evaluación de riesgos ergonómica la cual se ejecutó dentro de unos plazos marcados.El análisis está basado en la detección de las situaciones de riesgo mediante la observación in-situ del desarrollo del trabajo. Con esa finalidad se realizaron dos visitas al taller. La primera de ellas, tenía como objetivo detectar aquellas tareas que su ejecución representaba un riesgo para la salud del trabajador. Una vez detectadas las tareas, y previamente a la segunda visita, se realizó un pequeño estudio para determinar qué métodos ergonómicos se emplearían para realizar el estudio, conociendo de esa manera, que datos serían necesarios recoger al realizar una segunda visita. Seguidamente, se realizó una segunda visita al taller para realizar la observación de las tareas concretada previamente, y la medición de los datos.Finalmente, se procedió a procesar toda la información siguiendo las instrucciones pautadas por los métodos ergonómicos, comparando los resultados obtenidos con los niveles de riesgo admisibles, para extraer unas conclusiones del estudio, las cuales definían las condiciones laborales en las que se encontraba el trabajador. Como muchas de ellas, eran prácticamente inevitables para la ejecución de la tarea, se estudiaron una serie de medidas preventivas para reducir el nivel de riesgo. Una vez analizadas, fueron explicadas a los trabajadores mediante una pequeña formación con la finalidad de que las condiciones de trabajo mejoraran.
Resumo:
Yritysten vaihto-omaisuudenhallinnasta löytyy usein selviä puutteita. Yksi selkeä syy tähän on perinteisen ABC-analyysin riittämättömyys, joka pohjautuu puhtaasti historiatietoihin. ABC-analyysia oikein tulkitsemalla, voi siitä kuitenkin saada erinomaisen työkalun varastonhallintaan. Tämä edellyttää tuotteen elinkaarenvaiheen huomioimista. Tätä elinkaarenvaiheet huomioivaa ABC-analyysia kutsutaan elinkaaripohjaiseksi ABC-analyysiksi. Koska nykyisissä toiminnanohjausjärjestelmissä ei kuitenkaan ole mahdollista luokitella tuotteita tämän uuden menetelmän mukaisesti, syntyy tarve tukijärjestelmälle. Tukijärjestelmän tarkoituksena on sekä luokitella tuotteet elinkaaripohjaisen ABC-analyysin avulla että antaa tuotteille varastonohjaussuositukset Salmivuori Consulting Oy:n käyttämän ohjausmenetelmän mukaisesti. Varastotasojen määrittämistä helpottamaan luotiin järjestelmän yhteyteen vielä erillinen ohjaustyökalu. Lisäksi työssä on havainnollistettu keskimääräistä varaston arvoa sekä puutekustannuksia minimoivien varastotasojen valintaa case-esimerkin avulla. Järjestelmän luomien tuoteluokkien sekä varastonohjaussuositusten avulla, päätöksentekijällä on mahdollisuudet tehostaa yrityksen vaihto-omaisuudenhallintaa.
Resumo:
En este artículo se analizará la forma de los contratos de crédito al consumo, con especial atención a la manera en que debe exteriorizarse la declaración de voluntad (por escrito, en otro soporte duradero) y al contenido del contrato (menciones que forman parte de la información contractual). Lo primero es la forma "externa" y lo segundo es la forma "interna" del contrato. La diferenciación entre forma interna y forma externa también sirve para analizar el deber de información precontractual. Los efectos civiles previstos en la ley para el caso de contravención debe tener en cuenta esa distinción. El análisis se centra en la ley española de crédito al consumo, pero otros ordenamientos jurídicos se tomarán igualmente en consideración.
Resumo:
Daphne du Maurier’s popular classic Rebecca (1938) was traditionally marketed as a Gothic romance in which two lovers conquered the evil women that separated them. In more recent years, some feminist critics have provided a very different view of the story as a Gothic narrative about the dangers women suffer under patriarchal control. In this thesis, I propose, through a Gothic Studies and a Gender Studies reading, that the victim/abuser statuses in du Maurier’s novel cannot be equated to femininity and masculinity, respectively. Instead, I argue that villainy in Rebecca comes from being in a powerful position within patriarchy—a position that is occupied by both male and female characters
Resumo:
Resumen y objeto: Los socios de una Sociedad, en virtud del principio de autonomía de la voluntad, pueden definir a través de una cláusula expresa inserta en un contrato entre socios el tipo de incumplimiento que da lugar a la resolución de las compraventas de participaciones de esa sociedad. Dicha cláusula no puede considerarse como una condición puramente potestativa, dependiente de la exclusiva voluntad del deudor, puesto que está ligada al hecho del incumplimiento.
Resumo:
The time interval between successive migrations of biological species causes a delay time in the reaction-diffusion equations describing their space-time dynamics. This lowers the predicted speed of the waves of advance, as compared to classical models. It has been shown that this delay-time effect improves the modeling of human range expansions. Here, we demonstrate that it can also be important for other species. We present two new examples where the predictions of the time-delayed and the classical (Fisher) approaches are compared to experimental data. No free or adjustable parameters are used. We show that the importance of the delay effect depends on the dimensionless product of the initial growth rate and the delay time. We argue that the delay effect should be taken into account in the modeling of range expansions for biological species
Resumo:
Per diferents motius, l'acció de la justícia es troba permanentment d'actualitat. Una de les causes és la contínua novetat que prové de les propostes de modernització en els diversos àmbits, que tracten de pal·liar els dèficits amb els quals s'enfronta cada dia l'acció judicial. El debat és ja antic i permanent, sent que, simultàniament un ventall de projectes ha aparegut amb la intenció de dur a terme un canvi profund i determinant en la visió de l'estructura del Poder Judicial i dels serveis associats. En particular, la proposta de reforma de Llei Orgànica del Poder Judicial i de Demarcació i Planta, suposa la concentració de tots els jutjats a les capitals de província, amb el risc d'allunyament enfront dels ciutadans i problemes associats. L'esborrany de Codi Processal Penal aposta per un nou sistema de recerca a càrrec del Ministeri Fiscal, amb curts terminis taxats per a la finalització del procediment, promoció de la mediació i augment de les possibilitats de no continuació de la causa, a més una concentració i simplificació de totes les fases del procediment penal. D'altra banda, el Registre Civil ha estat retirat dels jutjats però, malgrat el transcurs del temps, no s'és capaç d'identificar a quin col·lectiu li correspondrà aquesta funció, amb la conseqüent generació d'una important inquietud social. Aquestes i altres novetats seran analitzades en profunditat, amb especial perspectiva des de l'àmbit de Catalunya, tractant d'aportar solucions i propostes de millora.
Resumo:
El sector agrícola de la Amazonía norte de Ecuador, está conformada por miles de pequeños agricultores que fundamentan principalmente sus ingresos en los cultivos de café, cacao. La necesidad de contar con mayores ingresos económicos provoca que los agricultores incursionen en cultivos. Esta condición determina que los procesos de producción tengan diferentes comportamientos frente al uso del suelo. Determinar los principales patrones de uso del suelo como generadores de ingresos económicos, permite tener una mejor óptica de cómo está diversificada la producción en términos de dinero. Este artículo inicia abordando algunas consideraciones necesarias para enmarcarse en cómo ha evolucionado la forma de uso del suelo, se exponen distintos criterios de investigadores que explican este comportamiento. Seguidamente se analiza cómo los productores se embarcan en esa búsqueda por incrementar sus rentas adoptando diversas formas de cultivo. Posteriormente se establecen cuatro tipologías de productores muy bien definidas en torno al uso del suelo. Con los resultados obtenidos se entabla una discusión, que permite mostrar el porqué de ciertos comportamientos productivos. Finalmente, se presentan conclusiones en función de las tipologías encontradas acompañadas de información válida para la aplicación de políticas públicas, orientadas a mejorar los ingresos de los productores.
Resumo:
In a very short time, the Internet has become an enormous source of information for teachers and students alike, in various scientific fields and at different levels of education. However, not all of this information is as reliable as one would wish and it is not always presented in the right way, nor is the content suitably structured for our purposes. Teachers need easily accessible criteria for selecting, analysing and evaluating web pages for their students, while bearing in mind the level and the material they are working with. In this article, we present the fundamental steps towards the analysis and subsequent evaluation of web pages of interest in the teaching of the Earth Sciences at different levels of education: Primary Education, Obligatory Secondary Education and “Bachillerato” (Pre-University Education)