Search results for "Rates"
showing 10 items of 1636 documents
Oceka kačectva tekuŝih vod na osnovanii analiza kompleksa donnoj makrofauny. Primer monitoringa reki Śčinava Nemodlinska (Polʺša) v 1999-2005 godah
2008
Assessment of possibilities of the biotic index application in the biological monitoring of the running water quality
2003
Data from: Sex-specific effects of natural and sexual selection on the evolution of life span and ageing in Drosophila simulans
2015
1. Variation in the strength of age-dependent natural selection shapes differences in ageing rates across species and populations. Likewise, sexual selection can promote divergent patterns of senescence across the sexes. However, the effects of these processes on the evolution of ageing have largely been considered independently, and interactions between them are poorly understood. 2. We use experimental evolution to investigate how natural and sexual selection affect life span and ageing in Drosophila simulans. 3. Replicate populations were evolved under lifetime monogamy (relaxed sexual selection) or lifetime polyandry (elevated sexual selection) and at one of two temperatures, 25 °C (rel…
Limits to Arbitrage and Interest Rates: a Debate Between Keynes, Hawtrey and Hicks
2018
International audience; This paper deals with a debate between Hawtrey, Hicks and Keynes concerning the capacity of the central bank to influence the short-term and the long-term rates of interest. Both Hawtrey and Keynes considered the central bank’s ability to influence short-term rates of interest. However, they do not put the same emphasis on the study of the long-term rates of interest. According to Keynes, long-term rates are influenced by future expected short-term rates (1930, 1936), whereas for Hawtrey (1932, 1937, 1938), long-term rates are more dependent on the business cycle. Short-term rates do not have much effect on long-term rates according to Hawtrey. In 1939, Hicks enters …
Niche position drives interspecific variation in occupancy and abundance in a highly-connected lake system
2019
Highlights • We studied interspecific variation in occupancy and abundance of freshwater species. • Occupancy and abundance correlated positively for both diatoms and macroinvertebrates. • Niche position had clearest effects on variation in occupancy and abundance. • The more marginal the niche position, the rarer a species is. We examined how niche position, niche breadth, biological traits and taxonomic relatedness affect interspecific variation in occupancy and abundance of two commonly-used biological indicator groups, i.e. diatoms and macroinvertebrates. We studied 291 diatom and 103 macroinvertebrate species that occupied the littoral zones of a large (305 km2) highly-connected freshw…
Predictive models in assessment of macroinvertebrates in boreal rivers
2009
Jukka Aroviita tutki väitöskirjassaan jokien ja purojen biologisen tilan mittaamismenetelmiä. Aroviita osoitti, että ihmistoiminnan aiheuttamat biologiset muutokset voivat jäädä havaitsematta, jos eliöyhteisöjen luonnollista taustavaihtelua ei oteta kunnolla huomioon.- Tällöin vesistöjen saatetaan arvioida olevan paremmassa kunnossa kuin ne todellisuudessa ovatkaan. Muutosten tunnistamistarkkuuden tulisi olla mahdollisimman hyvä, sillä tila-arvioilla on myös juridisesti määräytyviä yhteiskunnallisia ja taloudellisia seuraamuksia, Aroviita toteaa. Vielä 1990-luvulla järvien ja jokien tilaa arvioitiin suurelta osin ihmisen näkökulmasta ja veden kemian perusteella. Nykylainsäädäntö edellyttää …
Fish introductions and light modulate food web fluxes in tropical streams : a whole-ecosystem experimental approach
2016
Decades of ecological study have demonstrated the importance of top-down and bottom-up controls on food webs, yet few studies within this context have quantified the magnitude of energy and material fluxes at the whole-ecosystem scale. We examined top-down and bottom-up effects on food web fluxes using a field experiment that manipulated the presence of a consumer, the Trinidadian guppy Poecilia reticulata, and the production of basal resources by thinning the riparian forest canopy to increase incident light. To gauge the effects of these reach-scale manipulations on food web fluxes, we used a nitrogen (15N) stable isotope tracer to compare basal resource treatments (thinned canopy vs. con…
Parasite avoidance behaviours in aquatic environments
2018
Parasites, including macroparasites, protists, fungi, bacteria and viruses, can impose a heavy burden upon host animals. However, hosts are not without defences. One aspect of host defence, behavioural avoidance, has been studied in the terrestrial realm for over 50 years, but was first reported from the aquatic environment approximately 20 years ago. Evidence has mounted on the importance of parasite avoidance behaviours and it is increasingly apparent that there are core similarities in the function and benefit of this defence mechanism between terrestrial and aquatic systems. However, there are also stark differences driven by the unique biotic and abiotic characteristics of terrestrial …
Improving statistical classification methods and ecological status assessment for river macroinvertebrates
2016
Aquatic ecosystems are facing a growing number of human-induced stressors and the need to implement more biomonitoring to assess the ecological status of water bodies is eminent. This dissertation aims at providing tools to reduce the costs and improve the accuracy of freshwater benthic macroinvertebrate biomonitoring. To improve the cost-e ciency, we consider automated classi cation and develop a novel classi er suitable for complex macroinvertebrate image data. To enhance the accuracy of macroinvertebrate biomonitoring, we study the statistical properties of the Percent Model A nity index crucial to current Finnish biomonitoring and the factors a ecting these statistics. Finally, we perfo…
Historia del Pensamiento Político Premoderno 03 Platón
2010
Tema 3 El pensamiento político de Platón 1. Platón 2. ¿Cuál es el contexto político e intelectual en el que vivirá Platón? Las guerras del Peloponeso. Platón y la dictadura de los Treinta Tiranos. Sócrates, el único político autentico de Atenas. La experiencia con el joven Dionisio de Siracusa. 3. Platón crea la Academia. Regreso a Siracusa. La Academia, centro de conocimiento. 4. El Mito de la caverna. 5. Justicia, estado y política: el rey-filósofo. 6. Ciudadanos, sofistas y Sócrates. 7. Teoría política de Platón: el Estado Ideal. 8. Teoría de la educación en Platón. 9. La República, obra de madurez de Platón. 10. Formas políticas de gobierno: Aristocracia. Timocracia. Oligarquía. Democra…