879 research outputs found
Traits influence responses to land-use and climate change in terrestrial vertebrates
Human activities have profoundly impacted global biodiversity. Currently, anthropogenic land-use and climate change figure among the major threats to the worldâs fauna. However, not all species respond similarly to these pressures. Interspecific variability in responses to human threats is notably underpinned by the fact that different species possess different ecological characteristics, some of them allowing species to cope with environmental changes, while others confer a disadvantage to species in modified environments. Understanding what renders species sensitive to anthropogenic pressures is vital to inform and prioritise conservation efforts. Yet, in terrestrial vertebrates, a group for which ecological data are the most abundant, it remains unclear which traits are associated with higher sensitivity to human pressures. The aims of my thesis are to investigate whether and which traits are associated with land-use responses and climate-change sensitivity in terrestrial vertebrates, and to highlight some of the consequences for ecosystem functioning. I first assess the global availability of ecological trait data for terrestrial vertebrates, identifying understudied groups and regions (e.g., Central-African reptiles). I then show that, at global scales, disturbed land uses negatively impact the functional diversity of vertebrate assemblages. Further, I find that in all classes, higher sensitivity to land-use and climate change is associated with narrower ranges, smaller habitat breadth and inability to use human-modified habitats. Both land-use responses and climate-change sensitivity are unevenly distributed among dietary groups, highlighting potential food-web disruptions in assemblages under pressure. Finally, I show that land-use responses are influenced by speciesâ energetic requirements, so that energetic fluxes within vertebrate assemblages are likely modified under human-driven land-use change. Although the large-scale consequences of biodiversity changes for ecosystem functioning remain to be fully understood, my thesis highlights a compositional reshaping of vertebrate assemblages under human pressure and furthers our understanding of anthropogenic impacts on biodiversity
Luxembourg's evolution from city to smart city with 5G
This paper aims at showing the link between the fifth-generation mobile network and the concept of smart cities. Herein, the goal is to argue how could Luxembourg evolve towards a smart city with 5G.
5G demonstrates several distinctions compared to its predecessor the fourth-generation, such as its ultra-high reliability and low-latency, its efficiency, capacity as well as its greater coverage. Thanks to those main characteristics, it is an enabler of many new use cases and it could potentially support Luxembourg tackle its main challenges that are mobility, housing, and healthcare. Although this technology seems to present new possible applications and capabilities, it also has drawbacks such as, amongst others, the need to have 5G-enabled devices to use it. Indeed, it does not appear to be the logical continuation of 4G but more of an advanced technology that could disrupt the decade ahead of us. Thereafter, the concept of a smart city is discussed and argued in this research paper, aiming to evaluate the smartness of Luxembourg regarding its public sector, and mostly the sectors representing the biggest defy for the country.
Academic literature has been studied in this research paper and compared with the conducted interviews of both the public sector and 5G. This has also been supported by the conduction of a survey that aimed to evaluate Luxembourgâs inhabitantsâ expectations and needs for the future of their country, and mainly regarding the three challenging sectors as well as their potential fears regarding the implementation of 5G in the Grand-Duchy. Advantages of Luxembourg to both become a smart city and to deploy 5G are discussed and counterbalanced with the challenges the city could face during this evolution towards an increased smartness
Contacts homme-eau et schistosomiase urinaire dans un village mauritanien = Water contact and urinary schistosomiasis in a Mauritanian village
Huit jours d'observations directes, de septembre à décembre 1985, dans un village d'endémie bilharzienne à #S. haematobium$ situé en zone sahélienne ont permis d'enregistrer 1226 contacts homme-eau dans la mare du village et d'analyser la responsabilité des diverses activités dans la transmission. Un indice d'exposition, intégrant la durée du contact, la surface corporelle exposée et la probabilité de présence de cercaires dans l'eau a été calculé pour chaque contact. Les activités domestiques, essentiellement féminines, ont représenté 62 % des contacts mais seulement 15 % de l'exposition totale. La situation est inverse pour les activités récréatives qui, impliquant principalement de jeunes garçons, n'étaient responsables que de 14 % des contacts mais de 70 % de l'exposition totale. Entre 6 et 20 ans l'exposition moyenne par contact est plus importante pour le sexe masculin. Une politique de prévention de la maladie par une action sur les contacts semble irréaliste dans le contexte étudié et le traitement sélectif des enfants ou des sujets fortement infectés apparaßt comme la stratégie de lutte la mieux adaptée. (Résumé d'auteur
Global gaps in trait data for terrestrial vertebrates
AIM: Trait data are increasingly being used in studies investigating the impacts of global changes on the structure and functioning of ecological communities. Despite a growing number of trait data collations for terrestrial vertebrates, there is to date no global assessment of the gaps and biases the data present. Here, we assess whether terrestrial vertebrate trait data are taxonomically, spatially and phylogenetically biased. LOCATION: Global. TIME PERIOD: Present. MAJOR TAXA STUDIED: Terrestrial vertebrates. METHODS: We compile seven ecological traits and quantify coverage as the proportion of species for which an estimate is available. For a species, we define completeness as the proportion of nonâmissing values across traits. We assess whether coverage and completeness differ across classes and examine phylogenetic biases in trait data. To investigate spatial biases, we test whether widerâranging species have more complete trait data than narrowâranging species. Additionally, we test whether speciesârich regions, which are of most concern for conservation, are less well sampled than speciesâpoor regions. RESULTS: Mammals and birds are well sampled even in speciesârich regions. For reptiles and amphibians (herptiles), only body size presents a high coverage (>80%), in addition to habitatârelated variables (amphibians). Herptiles are poorly sampled for other traits. The shortfalls are particularly acute in some speciesârich regions and for certain clades. Across all classes, geographically rarer species have less complete trait information. MAIN CONCLUSIONS: Trait information is less available on average in some of the most diverse areas and in geographically rarer species, both of which crucial for biodiversity conservation. Gaps in trait data might impede our ability to conduct largeâscale analyses, whereas biases can impact the validity of extrapolations. A shortâterm solution to the problem is to estimate missing trait data using imputation techniques, whereas a longerâterm and more robust filling of existing gaps requires continued dataâcollection efforts
Age-acquired resistance and predisposition to reinfection with Schistosoma haematobium after treatment with Praziquantel in Mali
Shuttling of the chaperones Unc45b and Hsp90a between the A band and the Z line of the myofibril
The formation of thick filaments in striated muscle involves the chaperones Hsp90a and Unc45. We show that Unc45b and Hsp90a, two zebrafish orthologues, colocalize with myosin during myofibrillogenesis and associate with the Z line when myofibril assembly is completed. In response to stress or damage to the myofiber, Unc45b and Hsp90a dissociate from the Z line and transiently associate with myosin. Although chaperone activity of Unc45b requires the full-length protein, only the central and Unc45-Cro1p-She4p domains are required to anchor it to the Z line, and multiple subdomains mediate association with nascent myosin. We propose that the Z line serves as a reservoir for chaperones, allowing a rapid mobilization in response to muscle damage. Our data are consistent with a differential affinity model as an explanation for the shuttling of the chaperones between the Z line and myosin
Intensive human land uses negatively affect vertebrate functional diversity
Land-use change is the leading driver of global biodiversity loss thus characterising its impacts on the functional structure of ecological communities is an urgent challenge. Using a database describing vertebrate assemblages in different land uses, we assess how the type and intensity of land use affect the functional diversity of vertebrates globally. We find that human land uses alter local functional structure by driving declines in functional diversity, with the strongest effects in the most disturbed land uses (intensely used urban sites, cropland and pastures), and among amphibians and birds. Both tropical and temperate areas experience important functional losses, which are only partially offset by functional gains. Tropical assemblages are more likely to show decreases in functional diversity that exceed those expected from species loss alone. Our results indicate that land-use change non-randomly reshapes the functional structure of vertebrate assemblages, raising concerns about the continuation of ecological processes sustained by vertebrates
Early visual evoked potentials are modulated by eye position in humans induced by whole body rotations
BACKGROUND: To reach and grasp an object in space on the basis of its image cast on the retina requires different coordinate transformations that take into account gaze and limb positioning. Eye position in the orbit influences the image's conversion from retinotopic (eye-centered) coordinates to an egocentric frame necessary for guiding action. Neuroimaging studies have revealed eye position-dependent activity in extrastriate visual, parietal and frontal areas that is along the visuo-motor pathway. At the earliest vision stage, the role of the primary visual area (V1) in this process remains unclear. We used an experimental design based on pattern-onset visual evoked potentials (VEP) recordings to study the effect of eye position on V1 activity in humans. RESULTS: We showed that the amplitude of the initial C1 component of VEP, acknowledged to originate in V1, was modulated by the eye position. We also established that putative spontaneous small saccades related to eccentric fixation, as well as retinal disparity cannot explain the effects of changing C1 amplitude of VEP in the present study. CONCLUSIONS: The present modulation of the early component of VEP suggests an eye position-dependent activity of the human primary visual area. Our findings also evidence that cortical processes combine information about the position of the stimulus on the retinae with information about the location of the eyes in their orbit as early as the stage of primary visual area
Effects of rarity form on species' responses to land use
Anthropogenic land-use change causes substantial changes in local and global biodiversity. Rare and common species can differ in sensitivity to land-use change, with rare species expected to be more negatively affected. Rarity may be defined in terms of geographic range size, population density or breadth of habitat requirements. How these three forms of rarity interact in determining global responses to land use is yet to be assessed. Using global data representing 912 vertebrate species, we test for differences in the responses to land use of species characterised by different types of rarity. Species considered rare with respect to all three forms of rarity showed particularly strong declines in disturbed land uses (more than 40% of species and 30% of individuals in the most disturbed land uses). In contrast, species common both geographically and numerically, and with broad habitat requirements, showed strong increases (up to 90% increase in species and 40% in abundance in some land uses). Our results suggest that efforts to understand the vulnerability of species to environmental changes should account for different types of rarity where possible. Our results also have potentially important implications for ecosystem functioning, given that rare species may play unique roles within ecosystems. Article impact statement: Rare species show stronger negative responses to anthropogenic land use than common species
- âŠ