December 2016. From University of Helsinki. The results are just published in the journal Nature Communications. We still know fairly little about the specific impacts of climate change and human activity, such as nutrient enrichment of waterways, on broad geographical scales. Researchers from the Department of Geosciences and Geography at the University of Helsinki, the Finnish Environment Institute, and the Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences have studied hundreds of microcosms in mountainous regions with the aid of natural temperature gradients in the studied areas, while modifying the enrichment level in field tests. The results indicate that the bacteria in elevated tropical areas are similar to e.g. those in arctic areas. As a result of changes in temperature and aquatic enrichment, significant alterations occur in the microcosms, and as the enrichment increases, biodiversity reduces, says Associate Professor Janne Soininen.
Altez Rogelio1Recibido: febrero, 2013 / Aceptado: julio, 20131 Universidad Central de Venezuela, Facultad de Ciencias Económicas y Sociales, Escuela de Antropología, Caracas- Venezuela. Correo electrónico: firstname.lastname@example.orgResumenCaracas ha sido impactada desde su fundación por cuatro terremotos que le han causado daños severos: 1641, 1812, 1900 y 1967. El único espacio que ha sido testigo continuo de estos temblores es su casco central o histórico, cuyas condiciones de sitio presentan una profundidad de sedimentos que aumenta los efectos de las ondas sísmicas. En este trabajo se pretende revisar las intensidades de esos temblores utilizando la Escala Macrosísmica Europea (EMS-98) y comparar sus efectos a través del tiempo y de los cambios ocurridos en la construcción de la ciudad. La investigación propone un modelo analítico para casos similares, a partir de lo cual se ponga en práctica una estrategia comparativa entre sismos destructores observando sus efectos sobre un mismo sitio a través del tiempo, tomando en cuenta las transformaciones ocurridas por los cambios históricos indefectibles a ese paso del tiempo y las condiciones geológicas de sitio para la asignación de intensidades.Palabras clave: Caracas; terremotos; intensidades; modelos comparativos
Abstract The tree of life is one of the most important organizing principles in biology1. Gene surveys suggest the existence of an enormous number of branches2, but even an approximation of the full scale of the tree has remained elusive. Recent depictions of the tree of life have focused either on the nature of deep evolutionary relationships3,4,5 or on the known, well-classified diversity of life with an emphasis on eukaryotes6. These approaches overlook the dramatic change in our understanding of life's diversity resulting from genomic sampling of previously unexamined environments. New methods to generate genome sequences illuminate the identity of organisms and their metabolic capacities, placing them in community and ecosystem contexts7,8. Here, we use new genomic data from over 1,000 uncultivated and little known organisms, together with published sequences, to infer a dramatically expanded version of the tree of life, with Bacteria, Archaea and Eukarya included. The depiction is both a global overview and a snapshot of the diversity within each major lineage. The results reveal the dominance of bacterial diversification and underline the importance of organisms lacking isolated representatives, with substantial evolution concentrated in a major radiation of such organisms. This tree highlights major lineages currently underrepresented in biogeochemical models and identifies radiations that are probably important for future evolutionary analyses. Early approaches to describe the tree of life distinguished organisms based on their physical characteristics and metabolic features. Molecular methods dramatically broadened the diversity that could be included in the tree because they circumvented the need for direct observation and experimentation by relying on sequenced genes as markers for lineages. Gene surveys, typically using the small subunit ribosomal RNA (SSU rRNA) gene, provided a remarkable and novel view of the biological world1,9,10, but questions about the structure and extent of diversity remain. Organisms from novel lineages have eluded surveys, because many are invisible to these methods due to sequence divergence relative to the primers commonly used for gene amplification7,11. Furthermore, unusual sequences, including those with unexpected insertions, may be discarded as artefacts7. Whole genome reconstruction was first accomplished in 1995 (ref. 12), with a near-exponential increase in the number of draft genomes reported each subsequent year. There are 30,437 genomes from all three domains of life—Bacteria, Archaea and Eukarya—which are currently available in the Joint Genome Institute's Integrated Microbial Genomes database (accessed 24 September 2015). Contributing to this expansion in genome numbers are single cell genomics13 and metagenomics studies. Metagenomics is a shotgun sequencing-based method in which DNA isolated directly from the environment is sequenced, and the reconstructed genome fragments are assigned to draft genomes14. New bioinformatics methods yield complete and near-complete genome sequences, without a reliance on cultivation or reference genomes7,15. These genome- (rather than gene) based approaches provide information about metabolic potential and a variety of phylogenetically informative sequences that can be used to classify organisms16. Here, we have constructed a tree of life by making use of genomes from public databases and 1,011 newly reconstructed genomes that we recovered from a variety of environments (see Methods). To render this tree of life, we aligned and concatenated a set of 16 ribosomal protein sequences from each organism. This approach yields a higher-resolution tree than is obtained from a single gene, such as the widely used 16S rRNA gene16. The use of ribosomal proteins avoids artefacts that would arise from phylogenies constructed using genes with unrelated functions and subject to different evolutionary processes. Another important advantage of the chosen ribosomal proteins is that they tend to be syntenic and co-located in a small genomic region in Bacteria and Archaea, reducing binning errors that could substantially perturb the geometry of the tree. Included in this tree is one representative per genus for all genera for which high-quality draft and complete genomes exist (3,083 organisms in total). Despite the methodological challenges, we have included representatives of all three domains of life. Our primary focus relates to the status of Bacteria and Archaea, as these organisms have been most difficult to profile using macroscopic approaches, and substantial progress has been made recently with acquisition of new genome sequences7,8,13. The placement of Eukarya relative to Bacteria and Archaea is controversial1,4,5,17,18. Eukaryotes are believed to be evolutionary chimaeras that arose via endosymbiotic fusion, probably involving bacterial and archaeal cells19. Here, we do not attempt to confidently resolve the placement of the Eukarya. We position them using sequences of a subset of their nuclear-encoded ribosomal proteins, an approach that classifies them based on the inheritance of their information systems as opposed to lipid or other cellular structures5. Figure 1 presents a new view of the tree of life. This is one of a relatively small number of three-domain trees constructed from molecular information so far, and the first comprehensive tree to be published since the development of genome-resolved metagenomics. We highlight all major lineages with genomic representation, most of which are phylum-level branches (see Supplementary Fig. 1 for full bootstrap support values). However, we separately identify the Classes of the Proteobacteria, because the phylum is not monophyletic (for example, the Deltaproteobacteria branch away from the other Proteobacteria, as previously reported2,20).
Where tardigrades belong in the tree of life is a difficult question. Some previous work suggests that these tiny animals that can survive intense environmental challenges are most closely related to nematodes, while other studies and the animals’ morphology point to arthropods as water bears’ nearest relatives. Now, an international team of scientists has compared detailed genome assemblies of two tardigrade species. While their analysis, published today (July 27) in PLOS Biology, sheds light on water bears’ ability to endure punishing circumstances, it does not resolve their evolutionary history. “Even the full genomes of two tardigrades, which the authors report here, were not sufficient to decide whether tardigrades were closer to the arthropods or the nematodes,” Thorsten Burmester, a biologist at the University of Hamburg in Germany who did not participate in the study, writes in an email to The Scientist. “Genome sequences from related phyla, which are not yet available, may help in the future.” Scientists have identified more than 1,200 species of tardigrades living on land, in freshwater, and in marine environments. The animals are no bigger than a grain of salt and look like chubby, bumbling bears with four pairs of legs. Many terrestrial species have the unique capacity to survive without water for years by drying themselves up, only to rehydrate when their environment—often a patch of moss—becomes hospitable again.
Stephen Hawking is the former Lucasian Professor of Mathematics at the University of Cambridge and author of A Brief History of Time which was an international bestseller. Now the Dennis Stanton Avery and Sally Tsui Wong- Avery Director of Research at the Department of Applied Mathematics and Theoretical Physics and Founder of the Centre for Theoretical Cosmology at Cambridge, his other books for the general reader include A Briefer History of Time, the essay collection Black Holes and Baby Universe and The Universe in a Nutshell. In 1963, Hawking contracted motor neurone disease and was given two years to live. Yet he went on to Cambridge to become a brilliant researcher and Professorial Fellow at Gonville and Caius College. From 1979 to 2009 he held the post of Lucasian Professor at Cambridge, the chair held by Isaac Newton in 1663. Professor Hawking has over a dozen honorary degrees and was awarded the CBE in 1982. He is a fellow of the Royal Society and a member of the US National Academy of Science. Stephen Hawking is regarded as one of the most brilliant theoretical physicists since Einstein.
A rare and cosmically important position While many space agencies hire planetary protection officers, they're often shared or part-time roles. In fact, only two such full-time roles exist in the world: one at NASA and the other at the European Space Agency. That's according to Catharine Conley, NASA's only planetary protection officer since 2014. Business Insider interviewed Conley most recently in March. "This new job ad is a result of relocating the position I currently hold to the Office of Safety and Mission Assurance, which is an independent technical authority within NASA," Conley told Business Insider in an email on Tuesday. (She did not say whether she planned to reapply for the position, which is held for at least three years but may be extended to five years.)
EI Museo del Instituto de Zoología Agrícola “Francisco Fernández Yépez” (MIZA), es una institución dedicada al estudio de la biodiversidad tropical. Tenemos la convicción de que el conocimiento de nuestro patrimonio biológico está íntimamente relacionado con su preservación y uso sostenible, es por ello que la educación ambiental es una herramienta vital para formar ciudadanos conscientes y protectores de nuestro patrimonio biológico.