Search results for "Season"
showing 10 items of 1002 documents
Essays On European Natural Gas Market
2018
La presente tesis ha cubierto diferentes aspectos de los mercados europeos del gas natural y la electricidad, en particular algunas propiedades que afectan a la efectividad de la cobertura, como la estacionalidad en varianza y en precios. Asimismo, se ha realizado un estudio de la prima de riesgo del gas natural, su relación con las variables de riesgo y su descomposición en una prima de riesgo de reinversión o ‘rollover’ y una prima de ‘preferencia por liquidez’ relacionada con el plazo. La tesis se compone de tres capítulos: el Capítulo I estudia la estacionalidad en los precios y la volatilidad y cómo mejora la efectividad de la cobertura teniendo en cuenta dicha estacionalidad; el Capít…
Girdles as the main infection site for Paradeontacylix kampachi (Sanguinicolidae) in the greater amberjack Seriola dumerili.
2003
In this study, we provide new information about the habitats selected by the blood fluke Paradeontacylix kampachi in the greater amberjack Seriola dumerili based on an exhaustive anatomical examination. From May to October 1998, 21 fish of the 0+ age class were collected from tanks of the Spanish Institute of Oceanography in Puerto de Mazarrón, Spain, for parasitological analysis. Individuals of P. kampachi were found in 17 of the 21 fish analysed (mean intensity +/- SD: 13.6 +/- 16.6; median: 6). Worms occurred in the girdles, cephalic kidney, sinus venosus, kidney and branchial arteries. A Friedman test with a post-hoc contrast revealed a significantly higher number of worms in the girdle…
High Temperatures Result in Smaller Nurseries which Lower Reproduction of Pollinators and Parasites in a Brood Site Pollination Mutualism
2014
In a nursery pollination mutualism, we asked whether environmental factors affected reproduction of mutualistic pollinators, non-mutualistic parasites and seed production via seasonal changes in plant traits such as inflorescence size and within-tree reproductive phenology. We examined seasonal variation in reproduction in Ficus racemosa community members that utilise enclosed inflorescences called syconia as nurseries. Temperature, relative humidity and rainfall defined four seasons: winter; hot days, cold nights; summer and wet seasons. Syconium volumes were highest in winter and lowest in summer, and affected syconium contents positively across all seasons. Greater transpiration from the…
Erratum: “The Role of Humidity in Associations of High Temperature with Mortality: A Multicountry, Multicity Study”
2019
There is strong experimental evidence that physiologic stress from high temperatures is greater if humidity is higher. However, heat indices developed to allow for this have not consistently predicted mortality better than dry-bulb temperature.We aimed to clarify the potential contribution of humidity an addition to temperature in predicting daily mortality in summer by using a large multicountry dataset.In 445 cities in 24 countries, we fit a time-series regression model for summer mortality with a distributed lag nonlinear model (DLNM) for temperature (up to lag 3) and supplemented this with a range of terms for relative humidity (RH) and its interaction with temperature. City-specific as…
Long-term changes of precipitation in Latvia
2010
This study investigated long-term variability and trends in Latvia's annual, seasonal, monthly and daily precipitation using data from 10 meteorological stations for the period 1925–2006 and from station Riga University for the period 1850–2006. The obtained results indicate that during the 20th century a significant increase in precipitation has occurred in the cold season while the warm period showed a decreasing tendency. The annual precipitation totals showed a slight decrease, at half of the studied stations, due to opposite tendencies in cold season and warm season. The long-term trend in the annual precipitation in Riga (from 1850) was positive with large interannual and interdecadal…
Wheat growth simulation and yield prediction with seasonal forecasts and a numerical model
2007
Abstract Wheat is a major winter crop in northern Italy. Italian agricultural markets and government agencies would undoubtedly benefit from the early availability of wheat yield forecasts at the regional and national scales as useful support in decision making. In this study we tested the skill of seasonal weather forecasts, in combination with observed weather data, as input to a crop model working in water limited conditions. The observations were used to simulate wheat growth from sowing up to 2 months before harvest, while seasonal forecasts were used afterwards to predict final yields. Observations included climatic variables and water table levels from a location in the Po river plai…
Transient soil-moisture dynamics and climate change in Mediterranean ecosystems
2008
[1] Plants in Mediterranean ecosystems have developed different strategies to cope with transient soil-moisture dynamics induced by the markedly out of phase seasonal behavior of rainfall and temperature. Deep-rooted plants use the soil moisture stored in the wet winter (extensive users), while shallower rooted plants exploit both the wet season storage and the more sporadic growing season rainfall (intensive users). Using stochastic models of soil-moisture dynamics, we present an analytical and numerical description of the probabilistic structure of the soil-moisture storage at the beginning of the growing season in relation to the dynamics of the wet season and then study its evolution du…
Spatial distribution and temporal changes in river water temperature in the Baltic States
2017
Abstract The thermal regime of rivers in the Baltic States (Estonia, Latvia and Lithuania) is not sufficiently studied. The presented research describes the spatial distribution and temporal variation of river water temperature (WT) in the Baltic States using a unified methodology. The object of the research is the WT of rivers during the warm season (May–October) and the warmest month of the year (July). The contour maps of WT were compiled for the rivers of the Baltic States using data series for the period 1961–1990 from 17 water measuring stations in Estonia (EST), 36 stations in Latvia (LV) and 40 stations in Lithuania (LT). These maps allow the evaluation of WT for the unmonitored riv…
Combining a data-driven approach with seasonal forecasts data to predicting reservoir water volume in the Mediterranean area.
2021
<p>Artificial reservoirs are one of the main water supply resources in the Mediterranean areas; their management can be strongly affected by the problems of drought and water scarcity. The reservoir water level is the result of the hydrological processes occurring in the upstream catchment, which, in turn, depend on meteorological variables, such as rainfall and temperature. It follows that a reliable forecast model of the meteorological forcing, along with a reliable water balance model, could enhance the correct management of a reservoir. With regard to the rainfall/temperature forecast model, the use of forecast climate data in the mid-term may provide further support for t…
Stable isotopes of water as a tool to study groundwater–seawater interactions in coastal south-eastern Sicily
2009
Summary Stable isotopes of hydrogen (δD) and oxygen (δ 18 O) in groundwater, submarine springs and seawater collected in coastal south-eastern Sicily were investigated. While the spatial distribution of δ 18 O in groundwater showed that most of the heavy-isotope-depleted samples (from −5.7‰ to −6.9‰) were located in the higher portion of the Hyblean Mountains, more positive values (from −3.4‰ to −5.6‰) were found in the marginal areas. The isotope composition of submarine springs was characterized by significant variability (δ 18 O between −5.6‰ and +1.0‰ and δD between −30‰ and +5.0‰) reflecting seasonal variations and different seawater contributions. The isotopic and chemical composition…