73 research outputs found
Seismometer to Investigate Ice and Ocean Structure (SIIOS)
No abstract availabl
Patterns of Positive Selection and Neutral Evolution in the Protein-Coding Genes of Tetraodon and Takifugu
Recent genome-wide analyses have revealed patterns of positive selection acting on protein-coding genes in humans and mammals. To assess whether the conclusions drawn from these analyses are valid for other vertebrates and to identify mammalian specificities, I have investigated the selective pressure acting on protein-coding genes of the puffer fishes Tetraodon and Takifugu. My results indicate that the strength of purifying selection in puffer fishes is similar to previous reports for murids but stronger in hominids, which have a smaller population size. Gene ontology analyses show that more than half of the biological processes targeted by positive selection in mammals are also targeted in puffer fishes, highlighting general patterns for vertebrates. Biological processes enriched with positively selected genes that are shared between mammals and fishes include immune and defense responses, signal transduction, regulation of transcription and several of their descendent terms. Mammalian-specific processes displaying an excess of positively selected genes are related to sensory perception and neurological processes. The comparative analyses also revealed that, for both mammals and fishes, genes encoding extracellular proteins are preferentially targeted by positive selection, indicating that adaptive evolution occurs more often in the extra-cellular environment rather than inside the cell. Moreover, I present here the first genome-wide characterization of neutrally-evolving regions of protein-coding genes. This analysis revealed an unexpectedly high proportion of genes containing both positively selected motifs and neutrally-evolving regions, uncovering a strong link between neutral evolution and positive selection. I speculate that neutrally-evolving regions are a major source of novelties screened by natural selection
The status of the world's land and marine mammals: diversity, threat, and knowledge
Knowledge of mammalian diversity is still surprisingly disparate, both regionally and taxonomically. Here, we present a comprehensive assessment of the conservation status and distribution of the world's mammals. Data, compiled by 1700+ experts, cover all 5487 species, including marine mammals. Global macroecological patterns are very different for land and marine species but suggest common mechanisms driving diversity and endemism across systems. Compared with land species, threat levels are higher among marine mammals, driven by different processes (accidental mortality and pollution, rather than habitat loss), and are spatially distinct (peaking in northern oceans, rather than in Southeast Asia). Marine mammals are also disproportionately poorly known. These data are made freely available to support further scientific developments and conservation action
Expert range maps of global mammal distributions harmonised to three taxonomic authorities
AimComprehensive, global information on species' occurrences is an essential biodiversity variable and central to a range of applications in ecology, evolution, biogeography and conservation. Expert range maps often represent a species' only available distributional information and play an increasing role in conservation assessments and macroecology. We provide global range maps for the native ranges of all extant mammal species harmonised to the taxonomy of the Mammal Diversity Database (MDD) mobilised from two sources, the Handbook of the Mammals of the World (HMW) and the Illustrated Checklist of the Mammals of the World (CMW).LocationGlobal.TaxonAll extant mammal species.MethodsRange maps were digitally interpreted, georeferenced, error-checked and subsequently taxonomically aligned between the HMW (6253 species), the CMW (6431 species) and the MDD taxonomies (6362 species).ResultsRange maps can be evaluated and visualised in an online map browser at Map of Life (mol.org) and accessed for individual or batch download for non-commercial use.Main conclusionExpert maps of species' global distributions are limited in their spatial detail and temporal specificity, but form a useful basis for broad-scale characterizations and model-based integration with other data. We provide georeferenced range maps for the native ranges of all extant mammal species as shapefiles, with species-level metadata and source information packaged together in geodatabase format. Across the three taxonomic sources our maps entail, there are 1784 taxonomic name differences compared to the maps currently available on the IUCN Red List website. The expert maps provided here are harmonised to the MDD taxonomic authority and linked to a community of online tools that will enable transparent future updates and version control
Airports Offer Unrealized Potential for Alternative Energy Production
Scaling up for alternative energy such as solar, wind, and biofuel raises a number of environmental issues, notably changes in land use and adverse effects on wildlife. Airports offer one of the few land uses where reductions in wildlife abundance and habitat quality are necessary and socially acceptable, due to risk of wildlife collisions with aircraft. There are several uncertainties and limitations to establishing alternative energy production at airports, such as ensuring these facilities do not create wildlife attractants or other hazards. However, with careful planning, locating alternative energy projects at airports could help mitigate many of the challenges currently facing policy makers, developers, and conservationists
3D Printing and MEMS Propulsion for the RAMPART 2U CUBESAT
A volunteer consortium of the individuals and organizations listed on the title page of this document is using rapid prototyping and MEMS technologies to design and build a 2U RAMPART CUBESAT (RApidprototypedMemsPropulsionAndRadiationTest CUBEflowSATellite). f being manifested on a Falcon 1e launch. The flight of this satellite is intended to certify warm gas propulsion subsystems and magnetic stabilization for Cubesat orbital altitude adjustment, as well as rapid prototyping methods of building one-piece satellite structures, propellant tanks, printed circuit board cages, erectable solar panels, antenna deployment mechanisms, etc. at a fraction of the cost of current methods. Design revisions are being accommodated with a minimum of effort, time and expense. New laser-sintered materials with improved mechanical and thermal properties are being adapted for space use from the Formula 1 Racing field. Polymer sealants and metal platings have been utilized on surfaces inside and outside the satellite to eliminate outgassing and to aid in thermal management. This paper describes the use of these techniques to design-print-fly a 2U Cubesat that will raise its own apogee altitude to 1200 km, just below the equatorial inner Van Allen Radiation Belt, following deployment from its launch vehicle into an initial 450km circular orbit with an inclination of 45 deg. The satellite will measure incident energetic particle flux, together with the performance of new, improved radiation-hardened Cubeflow components and circuits and high-performance solar cells and cover glasses in that enhanced radiation environment, and telemeter those measurements to a redundant international ground station network
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