Search results for "Vertical"
showing 10 items of 417 documents
Night, day, sunrise, sunset: do fish under snow and ice recognize the difference?
2008
1. Although boreal lakes are ice-covered for several months annually, little is known about the behaviour of fish under ice. To consider the reasons for diel vertical migrations (DVM) it is important to compare periods under ice as opposed to under open water. Echosounding provides a tool for non-intrusive continuous monitoring of fish, even in winter. 2. Changes in the vertical distribution of fish through six 48-h periods were monitored using a stationary, mounted echosounder that beamed vertically either from the bottom up or from the surface down from February to April, 2003. The up-beaming and down-beaming transducers were run alternately for 24 h each over the 48-h period. Standard ec…
Behavioral responses of Atlantic cod to sea temperature changes
2015
Understanding responses of marine species to temperature variability is essential to predict impacts of future climate change in the oceans. Most ectotherms are expected to adjust their behavior to avoid extreme temperatures and minimize acute changes in body temperature. However, measuring such behavioral plasticity in the wild is challenging. Combining 4 years of telemetry-derived behavioral data on juvenile and adult (30–80 cm) Atlantic cod (Gadus morhua), and in situ ocean temperature measurements, we found a significant effect of sea temperature on cod depth use and activity level in coastal Skagerrak. During summer, cod were found in deeper waters when sea surface temperature increase…
Rotifer vertical distribution in a strongly stratified lake: a multivariate analysis
1998
The main source of variation of rotifer species distributions in lake Arcas-2, a small karstic lake near Cuenca (Spain), was explored by means of principal components factor (PCA) and canonical correlation (CCA) analyses. PCA was performed using rotifer densities and CCA using rotifer densities plus physical and chemical parameters. Factor 1 of PCA separated summer species from winter-spring species and Factor 2 accounted for the variation in the vertical profile. Three summer species with different food habits (Polyarthra dolichoptera, Hexarthra mira and Asplanchna girodi) were grouped together at the positive end of Factor 1, while Factor 2 separated the two hypolimnetic species (Filinia …
The effect of temperature fluctuations on oxygen consumption and ammonia excretion of underyearling Lake Inari Arctic charr
1998
Underyearling Lake Inari Arctic charr Salvelinus alpinus were acclimated to 11·0) C for 3 weeks, and then one group was maintained at 11·0) C and others were exposed to 14·4) Cconst, 17·7) Cconst or a diel fluctuating temperature of 14·3° C ± 1° C (14·3° Cfluc). Routine rates of oxygen consumption and ammonia excretion were measured over 10 days before the temperature change and over 31 days following the change. Measurements were made on fish that were feeding and growing. The temperature increase produced an immediate increase in oxygen consumption. There was then a decline over the next few days, suggesting that thermal acclimation was rapid. For groups exposed to constant temperature th…
Diel vertical movements of zooplankton in lake La Cruz (Cuenca, Spain)
2000
The study of diel vertical movements of zooplankton in a small meromictic karstic lake (lake La Cruz), presenting highly stratified waters, was performed using two different methodologies: (i) samples were taken along the vertical profile and were compared at different hours in a diel cycle; (ii) some plankton traps were located at different depths, covering different periods of time, to catch organisms going upwards and downwards. The main subject of this study has been the vertical movements affecting rotifers since they were dominant in the zooplankton of this lake, but we have also included the results obtained for other zooplankton groups. The results indicate an almost general movemen…
Copepod limnocalanus macrurus mating in relation to vertical migrations and aspects of feeding rates in the Bothnian Sea (Baltic Sea)
2006
The studies of calanoid copepod Limnocalanus macrurus feeding rates and mating related to vertical migration were conducted in October 2005 in the Bothnian Sea. The monocyclic copepod Limnocalanus macrurus develops mostly to adult and larger copepodites stages in autumn and these stages were investigated. Bothnian Sea is a brackish-water basin in Baltic Sea with comparatively big depth therefore Limnocalanus macrurus which prefer to live in deep and cold water is more abundant in this Baltic Sea part. Recent observations in the Bothnian Sea showed that Limnocalanus macrurus performs diel vertical migrations and adults approve stricter tendency to stay under thermocline layer at night than c…
Japan's FDI drivers in a time of financial uncertainty. New evidence based on Bayesian Model Averaging
2021
En este artículo analizamos los determinantes del stock de FDI saliente de Japón para el período 1996–2017. Este período es especialmente relevante ya que abarca un proceso de creciente globalización económica y dos crisis financieras. Para ello, consideramos un amplio conjunto de variables candidatas basadas en la teoría, así como en análisis empíricos previos. Nuestra muestra incluye un total de 27 países anfitriones. Seleccionamos las covariables utilizando una metodología basada en datos, el análisis Bayesian Model Averaging (BMA). Además, también analizamos si estos determinantes cambian según el grado de desarrollo (emergentes vs desarrollados) o las áreas geográficas (UE vs Asia Orie…
Quality pricing-to-market
2014
We examine firm's pricing-to-market decisions in vertically differentiated industries featuring a large number of firms that compete monopolistically in the quality space. Firms sell goods of heterogeneous quality to consumers with non-homothetic preferences that differ in their income and thus their marginal willingness to pay for quality increments. We derive closed-form solutions for the pricing game under costly international trade, thus establishing existence and uniqueness. We then examine how the interaction of good quality and market demand for quality affects firms' pricing-to-market decisions. The relative price of high quality goods compared to that of low quality goods is an inc…
Un modelo no hidrostático global con coordenada vertical basada en altura
2015
Memoria presentada en la Universitat de València para optar grado de de Doctor Esta tesis documenta la investigación que he realizado en modelización atmosférica: se parte de las ecuaciones físicas de la atmósfera y se aplican métodos numéricos eficientes para encontrar una solución a dichas ecuaciones a partir de unas condiciones iniciales dadas. Para este fin, se ha desarrollado un modelo atmosférico cuyas características principales son: espectral en la representación horizontal de los campos, discretización vertical de alto orden de exactitud, y semi-implícito en la integración temporal. Además, el modelo es no hidrostático y tiene una coordenada vertical basada en altura, en vez de la …
Compensation verticale et compensation horizontale pour les familles avec enfants : une comparaison des approches française et québécoise
1986
International audience; L'analyse des politiques familiales demande que l'on ait au préalable défini les objectifs potentiels de ces politiques. Ceux-ci sont discutés en termes de compensation verticale, de compensation horizontale positive et compensation horizontale normative. Dans le cadre d'une politique familiale et de son influence sur la natalité, l'efficacité des techniques mises en œuvre ne peut être appréciée qu'un retard de l'importance relative accordée aux conceptions sociales de la compensation des charges familiales. L'étude identifie les différences systématiques entre la France et le Québec relativement à la politique familiale ; ce qui conduit à caractériser avec précision…