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showing 10 items of 363 documents
Modelling soil moisture at SMOS scale by use of a SVAT model over the Valencia Anchor Station
2010
16 páginas, 9 figuras, 5 tablas.
Global-Scale Evaluation of Roughness Effects on C-Band AMSR-E Observations
2015
Quantifying roughness effects on ground surface emissivity is an important step in obtaining high-quality soil moisture products from large-scale passive microwave sensors. In this study, we used a semi-empirical method to evaluate roughness effects (parameterized here by the parameter) on a global scale from AMSR-E (Advanced Microwave Scanning Radiometer for EOS) observations. AMSR-E brightness temperatures at 6.9 GHz obtained from January 2009 to September 2011, together with estimations of soil moisture from the SMOS (Soil Moisture and Ocean Salinity) L3 products and of soil temperature from ECMWF’s (European Centre for Medium-range Weather Forecasting) were used as inputs in a retrieval…
Phenological and intrinsic predictors of mite and haemacoccidian infection dynamics in a Mediterranean community of lizards
2021
Ectotherms are vulnerable to environmental changes and their parasites are biological health indicators. Thus, parasite load in ectotherms is expected to show a marked phenology. This study investigates temporal host–parasite dynamics in a lizard community in Eastern Spain during an entire annual activity period. The hosts investigated were Acanthodactylus erythrurus, Psammodromus algirus and Psammodromus edwardsianus, three lizard species coexisting in a mixed habitat of forests and dunes, providing a range of body sizes, ecological requirements and life history traits. Habitat and climate were considered as potential environmental predictors of parasite abundance, while size, body conditi…
MAB2.0 project: Integrating algae production into wastewater treatment
2018
Abstract Different species of microalgae are highly efficient in removing nutrients from wastewater streams and are able to grow using flue gas as a CO2 source. These features indicate that application of microalgae has a promising outlook in wastewater treatment. However, practical aspects and process of integration of algae cultivation into an existing wastewater treatment line have not been investigated. The Climate-KIC co-funded Microalgae Biorefinery 2.0 project developed and demonstrated this integration process through a case study. The purpose of this paper is to introduce this process by phases and protocols, as well as report on the challenges and bottlenecks identified in the cas…
EPIDEMIOLOGY OF PLASMODIUM RELICTUM INFECTION IN THE HOUSE SPARROW.
2014
International audience; : Abstract In vertebrates, multiple host characteristics and environmental factors are known to influence infectious disease dynamics. Here, we investigated variability in prevalence and parasitemia of Plasmodium relictum in the house sparrow (Passer domesticus), across a large number of rural and urban populations (n = 16). We found that prevalence was not predicted by any of the host traits investigated (age, sex, body mass or wing length). However, parasitemia was significantly higher in females when compared to males and in 1-yr-olds as compared to older individuals. Neither prevalence nor parasitemia differed according to habitat type (urban vs. rural). These re…
Impact of host nutritional status on infection dynamics and parasite virulence in a bird-malaria system.
2014
10 pages; International audience; Host resources can drive the optimal parasite exploitation strategy by offering a good or a poor environment to pathogens. Hosts living in resource-rich habitats might offer a favourable environment to developing parasites because they provide a wealth of resources. However, hosts living in resource-rich habitats might afford a higher investment into costly immune defences providing an effective barrier against infection. Understanding how parasites can adapt to hosts living in habitats of different quality is a major challenge in the light of the current human-driven environmental changes. We studied the role of nutritional resources as a source of phenoty…
Sensitive measure of prevalence and parasitaemia of haemosporidia from European blackbird (Turdus merula) populations: value of PCR-RFLP and quantita…
2006
8 pages; International audience; Haemosporidian parasites are common in birds in which they act as an important selective pressure. While most studies so far have focused on the effect of their prevalence on host life-history traits, no study has measured the effect of parasitaemia. We developed molecular methods to detect, identify and quantify haemosporidia in 2 natural populations of the Blackbird Turdus merula. Three different parasite genotypes were found - 1 Haemoproteus and 2 Plasmodium. A PCR-RFLP screening revealed that only approximately 3% of blackbirds were free of parasites, compared to the 34% of uninfected birds estimated by blood smear screening. A quantitative PCR (q-PCR) a…
Predictions of avian Plasmodium expansion under climate change.
2013
International audience; Vector-borne diseases are particularly responsive to changing environmental conditions. Diurnal temperature variation has been identified as a particularly important factor for the development of malaria parasites within vectors. Here, we conducted a survey across France, screening populations of the house sparrow (Passer domesticus) for malaria (Plasmodium relictum). We investigated whether variation in remotely-sensed environmental variables accounted for the spatial variation observed in prevalence and parasitemia. While prevalence was highly correlated to diurnal temperature range and other measures of temperature variation, environmental conditions could not pre…
Effect of repeated exposure to Plasmodium relictum (lineage SGS1) on infection dynamics in domestic canaries.
2010
7 pages; International audience; Parasites are known to exert strong selection pressures on their hosts and, as such, favour the evolution of defence mechanisms. The negative impact of parasites on their host can have substantial consequences in terms of population persistence and the epidemiology of the infection. In natural populations, however, it is difficult to assess the cost of infection while controlling for other potentially confounding factors. For instance, individuals are repeatedly exposed to a variety of parasite strains, some of which can elicit immunological memory, further protecting the host from subsequent infections. Cost of infection is, therefore, expected to be partic…
Variational Approximations for Generalized Linear Latent Variable Models
2017
Generalized linear latent variable models (GLLVMs) are a powerful class of models for understanding the relationships among multiple, correlated responses. Estimation, however, presents a major challenge, as the marginal likelihood does not possess a closed form for nonnormal responses. We propose a variational approximation (VA) method for estimating GLLVMs. For the common cases of binary, ordinal, and overdispersed count data, we derive fully closed-form approximations to the marginal log-likelihood function in each case. Compared to other methods such as the expectation-maximization algorithm, estimation using VA is fast and straightforward to implement. Predictions of the latent variabl…