The lion's share of bacteria in various environments cannot be cloned in the laboratory and thus cannot be sequenced using existing technologies. A major goal of single-cell genomics is to complement gene-centric metagenomic data with whole-genome assemblies of uncultivated organisms. Assembly of single-cell data is challenging because of highly non-uniform read coverage as well as elevated levels of sequencing errors and chimeric reads. We describe SPAdes, a new assembler for both single-cell and standard (multicell) assembly, and demonstrate that it improves on the recently released E+V-SC assembler (specialized for single-cell data) and on popular assemblers Velvet and SoapDeNovo (for multicell data). SPAdes generates single-cell assemblies, providing information about genomes of uncultivatable bacteria that vastly exceeds what may be obtained via traditional metagenomics studies. SPAdes is available online ( http://bioinf.spbau.ru/spades ). It is distributed as open source software.

SPAdes, a new genome assembly algorithm and its applications to single-cell sequencing ( 7th Annual SFAF Meeting, 2012)

The solar chemical composition is an important ingredient in our understanding of the formation, structure, and evolution of both the Sun and our Solar System. Furthermore, it is an essential refer ...

The Chemical Composition of the Sun

Rising atmospheric carbon dioxide (CO2), primarily from human fossil fuel combustion, reduces ocean pH and causes wholesale shifts in seawater carbonate chemistry. The process of ocean acidification is well documented in field data, and the rate will accelerate over this century unless future CO2 emissions are curbed dramatically. Acidification alters seawater chemical speciation and biogeochemical cycles of many elements and compounds. One well-known effect is the lowering of calcium carbonate saturation states, which impacts shell-forming marine organisms from plankton to benthic molluscs, echinoderms, and corals. Many calcifying species exhibit reduced calcification and growth rates in laboratory experiments under high-CO2 conditions. Ocean acidification also causes an increase in carbon fixation rates in some photosynthetic organisms (both calcifying and noncalcifying). The potential for marine organisms to adapt to increasing CO2 and broader implications for ocean ecosystems are not well known; both are high priorities for future research. Although ocean pH has varied in the geological past, paleo-events may be only imperfect analogs to current conditions.

/pdf/ocean-acidification-the-other-co-2-problem-4h18mw2cpj.pdf

Ocean Acidification: The Other CO 2 Problem

Climate change 2014 - Synthesis Report

About Supramolecular Assemblies of π-Conjugated Systems

Indigenous reduced carbon has been observed in the Martian meteorite Nakhla. For the first time we have analyzed the in situ carbon by a suite of micro-analytical techniques in order to identify and characterize the reduced carbonaceous matter. Optical analysis of the Nakhla petrographic thin-section revealed the existence of a dark brown/red vein-filling material appearing as a series of bifurcating intrusions into a fine (<300 nm width) crack / fissure system within an olivine/augite groundmass. Micro-analytical analyses utilizing Focus Ion Beam (FIB) extraction techniques, FESEM/EDX, STEM/EDX, NanoSIMS Ion Microprobe, Laser Raman Spectroscopy, Stepped-Combustion Isotopic Mass Spectrometry have been utilized. The structure of the carbonaceous phase in Nakhla indicates it could not have been introduced allochthonously in its current physical form. The close association to a region of secondary mineralization (i.e., iddingsite) implies, although certainly does not confirm, a connection with the period of Martian aqueous alteration experienced by the rock. This carbonaceous material has similarities to macromolecular carbonaceous matter and yet possesses a complex structural and textural morphology that is not observed in carbonaceous or ordinary chondrite meteoritic kerogen. One of the possible origins for the carbonaceous matter is from biogenic processes operating on Mars.

Identification and analysis of carbon-bearing phases in the Martian meteorite Nakhla

Establishing the origin of short-lived radionuclides (SLRs) with half-lives ≤100 Myr has important implications for the astrophysical context of our Sun's birth place. We review here the different origins proposed for the variety of SLRs present in the solar accretion disk 4.57 Ga ago. Special emphasis is given to an enhanced Galactic background origin for 60Fe which was inherited from several supernovae belonging to previous episodes of star formation, rather than from a nearby, contemporaneous supernova.

The origin of 60Fe and other short-lived radionuclides in the early solar system

The stopping cross section, the straggling parameter, and three higher moments over the energy-loss cross section have been evaluated for a moving point charge interacting with atomic hydrogen. The aim was to estimate the accuracy of predictions based on four commonly used models for computation of stopping parameters. The standard of reference was a straight evaluation of the Born approximation. All considered models, i.e., the dielectric theory, the binary-encounter model, the kinetic theory, and the harmonic-oscillator model, have been shown to be capable of providing reliable predictions within their respective regimes of feasibility, but distinct variations show up from lower to higher moments and from higher to lower projectile energy.

Intercomparison of atomic models for computing stopping parameters from the Bethe theory: Atomic hydrogen.

Keywords: Core ; Os Reference EPFL-ARTICLE-177117doi:10.1126/science.1153710View record in Web of Science Record created on 2012-05-15, modified on 2016-08-09

http://www.mantleplumes.org/WebDocuments/Meibom2008.pdf

Anders Meibom

Papers

Identification and analysis of carbon-bearing phases in the Martian meteorite Nakhla

The origin of 60Fe and other short-lived radionuclides in the early solar system

Intercomparison of atomic models for computing stopping parameters from the Bethe theory: Atomic hydrogen.

The Rise and Fall of a Great Idea

Management of Marine Protected Areas: A Network Perspective