Search results for "Seasonality"
showing 10 items of 229 documents
Seagrass meadows at the extreme of environmental tolerance: the case ofPosidonia oceanicain a semi-enclosed coastal lagoon
2009
Atoll-like structures of the endemic Mediterranean seagrass Posidonia oceanica were encountered in the innermost area of the Stagnone di Marsala, a semi-enclosed coastal lagoon along the western coasts of Sicily. The area is characterized by limited water exchange with the open sea and by a marked seasonal variation of water salinity and temperature, reaching beyond the theoretical tolerance limits of the species. In the present study we determined the genetic composition of the atoll-like structures, as well as the growth performance and flowering rate of these stands. We also assessed whether and to what extent the atoll-like structures are genetically isolated from plants growing in mead…
The Early Spörer Minimum – A Period of Extraordinary Climate and Socio-economic Changes in Western and Central Europe
2016
Abstract. Throughout the last millennium, mankind was affected by prolonged deviations from the climate mean state. While periods like the Maunder Minimum in the 17th century have been assessed in greater detail, earlier cold periods such as the 15th century received much less attention due to the sparse information available. Based on new evidence from different sources ranging from proxy archives to model simulations, it is now possible to provide an end-to-end assessment about the climate state during an exceptionally cold period in the 15th century, the role of internal, unforced climate variability and external forcing in shaping these extreme climatic conditions, and the impacts on an…
Estimation of the Combined Effects of Ageing and Seasonality on Mortality Risk: An Application to Spain
2021
Abstract Despite the overwhelming evidence that shows the persistence of intra-annual variations on demographic events (deaths, birth dates and migration flows), life tables are computed and provided on an annual basis. This paper develops a new estimator for estimating sub-annual death rates that, considering the exact moment of occurrence (exact age and day) of events, concurrently accounts for ageing and calendar fluctuations. This paper also shows how modelling the intra-annual variations of death rates, through specific seasonal–ageing indexes, can be used as a tool for constructing new sub-annual tables from annual tables. This new methodology is exemplified using a real database of S…
Analysis and modelling of wind speed in New York
2010
In this paper we propose an ARMA time-series model for the wind speed at a single spatial location, and estimate it on in-sample data recorded in three different wind farm regions in New York state. The data have a three-hour granularity, but based on applications to financial wind derivatives contracts, we also consider daily average wind speeds. We demonstrate that there are large discrepancies in the behaviour of daily average and three-hourly wind speed records. The validation procedure based on out-of-sample observations reflects that the proposed model is reliable and can be used for various practical applications, like, for instance, weather prediction, pricing of financial wind cont…
Zooplankton dynamics during autumn circulation in a small, wind-sheltered, Mediterranean lake
2006
12 pages, and tables statistics.
Finnish salmon resistant to Gyrodactylus salaris: a long-term study at fish farms.
1996
Abstract The occurrence of Gyrodactylus salaris on Baltic salmon ( Salmo salar ), sea trout ( S. trutta m. trutta ) and brown trout ( S. trutta m. lacustris ) was examined from 1984 to 1993 at 4 fish farms (A, B, C and D) that produce smolts for stocking in northern Finland. No G. salaris was found on the sea or brown trout, but it did occur on salmon for 6–7 years at farms B, C and D, the prevalences of infection being 9.5%, 17.7% and 8.8% for salmon yearlings and smolts during that time, respectively, but less than 1.2% for fingerlings at farms B and C. Only brood stock salmon were infected at farm A in 4 years. The abundances of G. salaris increased during the second winter of each year …
Profiles and seasonal distribution of airborne fungi in indoor and outdoor environments at a French hospital
2009
International audience; A one-year prospective survey of fungal air contamination was conducted in outdoor air and inside two haematological units of a French hospital. Air was sampled with a portable Air System Impactor. During this period of survey, the mean viable fungal load was 122.1 cfu/m(3) in outdoor air samples, and 4.1 and 3.9 cfu/m(3) in samples from adult and pediatric haematology units, respectively. In outdoor samples, Cladosporium was the dominant genus (55%) while in the clinical units, Penicillium sp. (23 to 25%), Aspergillus sp. (15 to 23%) and Bjerkandera adusta (11 to 13%) were the most frequently recovered airborne fungi. The outdoor fungal load was far higher in autumn…
Absolute Humidity Influences the Seasonal Persistence and Infectivity of Human Norovirus
2014
ABSTRACT Norovirus (NoV) is one of the main causative agents of acute gastroenteritis worldwide. In temperate climates, outbreaks peak during the winter season. The mechanism by which climatic factors influence the occurrence of NoV outbreaks is unknown. We hypothesized that humidity is linked to NoV seasonality. Human NoV is not cultivatable, so we used cultivatable murine norovirus (MNV) as a surrogate to study its persistence when exposed to various levels of relative humidity (RH) from low (10% RH) to saturated (100% RH) conditions at 9 and 25°C. In addition, we conducted similar experiments with virus-like particles (VLPs) from the predominant GII-4 norovirus and studied changes in bin…
The Influence of Seasonality on the Economic Efficiency of Wastewater Treatment Plants
2010
Many tourist areas are often characterized with seasonal water demand. The influence of seasonality on water management is more intensive in the context of water scarcity. Thus the use of so-called non-conventional water resources in these areas becomes a key aspect. In this sense, efficient performance, both in technical and cost terms, favors water reuse possibilities and, therefore, increases the supply of non-conventional resources. In tourist areas, seasonality is a determining factor in the efficiency of wastewater treatment plants (WWTPs) as these are operating at full capacity only during the summer season while the rest of the year they have under-utilization problems. Using the Fr…
Seasonal and Inter-annual Variation of Evapotranspiration in Amazonia Based on Precipitation, River Discharge and Gravity Anomaly Data
2019
We analyzed seasonal and spatial variations of evapotranspiration (ET) for five Amazon sub-basins and their response to the 2015/16 El Nino episode using a recently developed water-budget approach. ET varied typically between similar to 7 and 10 cm/month with exception of the Xingu basin for which it varied between 10 and 15 cm/month. Outstanding features of ET seasonality are (i) generally weak seasonality, (ii) two ET peaks for the two very wet catchments Solimoes and Negro, with one occurring during the wet season and one during the drier season, and (iii) a steady increase of ET during the second half of the dry season for the three drier catchments (Madeira, Tapajos, Xingu). Peak ET oc…