363 research outputs found
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Detection of Microbial sulfate-reduction associated with buried stainless steel coupons
The objective of this study was to demonstrate applicability of an innovative radioactive isotope method for imaging microbial activity in geological materials to a comprehensive study of metal corrosion. The method was tested on a sample of stainless steel coupons that had been buried as part of a corrosion study initiated by the National Institute of Standards and Testing or NIST (known as National Bureau of Standards prior to 1988) in 1970. The images showed evidence of microbial activity that could be mapped on a millimeter scale to coupon surfaces. A second more conventional isotope tracer method was also used to provide a quantitative measure of the same type of microbial activity in soil proximal to the buried coupons. Together the techniques offer a method for evaluating low metabolic levels of activity that have the potential for significant cumulative corrosion effects. The methods are powerful tools for evaluation of potential for microbial induced corrosion to buried steel components used on pipelines, in the power and communications infrastructure, and in nuclear waste repository containers
Microbial Diversity in the Eukaryotic SAR Clade: Illuminating the Darkness Between Morphology and Molecular Data
Despite their diversity and ecological importance, many areas of the SAR—Stramenopila, Alveolata, and Rhizaria—clade are poorly understood as the majority (90%) of SAR species lack molecular data and only 5% of species are from well-sampled families. Here, we review and summarize the state of knowledge about the three major clades of SAR, describing the diversity within each clade and identifying synapomorphies when possible. We also assess the “dark area” of SAR: the morphologically described species that are missing molecular data. The majority of molecular data for SAR lineages are characterized from marine samples and vertebrate hosts, highlighting the need for additional research effort in areas such as freshwater and terrestrial habitats and “non-vertebrate” hosts. We also describe the paucity of data on the biogeography of SAR species, and point to opportunities to illuminate diversity in this major eukaryotic clade. See also the video abstract above
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Long Term Corrosion/Degradation Test Six Year Results
The Subsurface Disposal Area (SDA) of the Radioactive Waste Management Complex (RWMC) located at the Idaho National Engineering and Environmental Laboratory (INEEL) contains neutron-activated metals from non-fuel, nuclear reactor core components. The Long-Term Corrosion/Degradation (LTCD) Test is designed to obtain site-specific corrosion rates to support efforts to more accurately estimate the transfer of activated elements to the environment. The test is using two proven, industry-standard methods—direct corrosion testing using metal coupons, and monitored corrosion testing using electrical/resistance probes—to determine corrosion rates for various metal alloys generally representing the metals of interest buried at the SDA, including Type 304L stainless steel, Type 316L stainless steel, Inconel 718, Beryllium S200F, Aluminum 6061, Zircaloy-4, low-carbon steel, and Ferralium 255. In the direct testing, metal coupons are retrieved for corrosion evaluation after having been buried in SDA backfill soil and exposed to natural SDA environmental conditions for times ranging from one year to as many as 32 years, depending on research needs and funding availability. In the monitored testing, electrical/resistance probes buried in SDA backfill soil will provide corrosion data for the duration of the test or until the probes fail. This report provides an update describing the current status of the test and documents results to date. Data from the one-year and three-year results are also included, for comparison and evaluation of trends. In the six-year results, most metals being tested showed extremely low measurable rates of general corrosion. For Type 304L stainless steel, Type 316L stainless steel, Inconel 718, and Ferralium 255, corrosion rates fell in the range of “no reportable” to 0.0002 mils per year (MPY). Corrosion rates for Zircaloy-4 ranged from no measurable corrosion to 0.0001 MPY. These rates are two orders of magnitude lower than those specified in the performance assessment for the SDA. The corrosion on the carbon steel, beryllium, and aluminum were more evident with a clear difference in corrosion performance between the 4-ft and 10-ft levels. Notable surface corrosion products were evident as well as numerous pit initiation sites. Since the corrosion of the beryllium and aluminum is characterized by pitting, the geometrical character of the corrosion becomes more significant than the general corrosion rate. Both pitting factor and weight loss data should be used together. For six-year exposure, the maximum carbon steel corrosion rate was 0.3643 MPY while the maximum beryllium corrosion rate was 0.3282 MPY and the maximum aluminum corrosion rate was 0.0030 MPY
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Mating disruption of stonefruit pests using sprayable formulations of biodegradable films and pheromone
COVID-19 publications: Database coverage, citations, readers, tweets, news, Facebook walls, Reddit posts
© 2020 The Authors. Published by MIT Press. This is an open access article available under a Creative Commons licence.
The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1162/qss_a_00066The COVID-19 pandemic requires a fast response from researchers to help address biological,
medical and public health issues to minimize its impact. In this rapidly evolving context,
scholars, professionals and the public may need to quickly identify important new studies. In
response, this paper assesses the coverage of scholarly databases and impact indicators
during 21 March to 18 April 2020. The rapidly increasing volume of research, is particularly
accessible through Dimensions, and less through Scopus, the Web of Science, and PubMed.
Google Scholar’s results included many false matches. A few COVID-19 papers from the
21,395 in Dimensions were already highly cited, with substantial news and social media
attention. For this topic, in contrast to previous studies, there seems to be a high degree of
convergence between articles shared in the social web and citation counts, at least in the
short term. In particular, articles that are extensively tweeted on the day first indexed are
likely to be highly read and relatively highly cited three weeks later. Researchers needing wide
scope literature searches (rather than health focused PubMed or medRxiv searches) should
start with Dimensions (or Google Scholar) and can use tweet and Mendeley reader counts as
indicators of likely importance
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Estimates of biogenic methane production rates in deep marine sediments at Hydrate Ridge, Cascadia Margin
Methane hydrate found in marine sediments is thought to contain gigaton quantities of methane and is
considered an important potential fuel source and climate-forcing agent. Much of the methane in hydrates is
biogenic, so models that predict the presence and distribution of hydrates require accurate rates of in situ
methanogenesis. We estimated the in situ methanogenesis rates in Hydrate Ridge (HR) sediments by coupling
experimentally derived minimal rates of methanogenesis to methanogen biomass determinations for discrete
locations in the sediment column. When starved in a biomass recycle reactor, Methanoculleus submarinus
produced ca. 0.017 fmol methane/cell/day. Quantitative PCR (QPCR) directed at the methyl coenzyme M
reductase subunit A gene (mcrA) indicated that 75% of the HR sediments analyzed contained <1,000 methanogens/
g. The highest numbers of methanogens were found mostly from sediments <10 m below seafloor. By
considering methanogenesis rates for starved methanogens (adjusted to account for in situ temperatures) and
the numbers of methanogens at selected depths, we derived an upper estimate of <4.25 fmol methane
produced/g sediment/day for the samples with fewer methanogens than the QPCR method could detect. The
actual rates could vary depending on the real number of methanogens and various seafloor parameters that
influence microbial activity. However, our calculated rate is lower than rates previously reported for such
sediments and close to the rate derived using geochemical modeling of the sediments. These data will help to
improve models that predict microbial gas generation in marine sediments and determine the potential
influence of this source of methane on the global carbon cycle
The Right Place at the Right Time: Creative Spaces in Libraries
Purpose
This essay explores the recent trend in libraries: that of the establishment of spaces specifically set aside for creative work. The rise of these dedicated creative spaces is owed to a confluence of factors that happen to be finding their expression together in recent years. This essay examines the history of these spaces and explores the factors that gave rise to them and will fuel them moving forward.
Design/Methodology/Approach
A viewpoint piece, this essay combines historical research and historical/comparative analyses to examine the ways by which libraries have supported creative work in the past and how they may continue to do so into the 21st century.
Findings
The key threads brought together include a societal recognition of the value of creativity and related skills and attributes; the philosophies, values, and missions of libraries in both their longstanding forms and in recent evolutions; the rise of participatory culture as a result of inexpensive technologies; improved means to build community and share results of efforts; and library experience and historical practice in matters related to creativity. The chapter concludes with advice for those interested in the establishment of such spaces, grounding those reflections in the author’s experiences in developing a new creative space at Virginia Commonwealth University.
Originality/value
While a number of pieces have been written that discuss the practicalities of developing certain kinds of creative spaces, very little has been written that situates these spaces in larger social and library professional contexts; this essay begins to fill that gap
Electronic excitation of furfural as probed by high-resolution vacuum ultraviolet spectroscopy, electron energy loss spectroscopy, and ab initio calculations
13 págs.; 7 figs.; 8 tabs.© 2015 AIP Publishing LLC. The electronic spectroscopy of isolated furfural (2-furaldehyde) in the gas phase has been investigated using high-resolution photoabsorption spectroscopy in the 3.5-10.8 eV energy-range, with absolute cross section measurements derived. Electron energy loss spectra are also measured over a range of kinematical conditions. Those energy loss spectra are used to derive differential cross sections and in turn generalised oscillator strengths. These experiments are supported by ab initio calculations in order to assign the excited states of the neutral molecule. The good agreement between the theoretical results and the measurements allows us to provide the first quantitative assignment of the electronic state spectroscopy of furfural over an extended energy range.F.F.S. and P.L.V. acknowledge the Portuguese Foundation
for Science and Technology (FCT-MEC) through Grant Nos.
SFRH/BPD/68979/2010 and SFRH/BSAB/105792/2014,
respectively, the research Grant Nos. PTDC/FIS-ATO/1832/
2012 and UID/FIS/00068/2013. P.L.V. also acknowledges
his Visiting Research Fellow position at Flinders University,
Adelaide, South Australia. The Patrimoine of the University
of Liège, the Fonds National de la Recherche Scientifique,
and the Fonds de la Recherche Fondamentale Collective of
Belgium have also supported this research. E.L. and R.F.C.N.
thank CNPq (Brazil) and the Science Without Borders
Programme for opportunities to study abroad. The authors
wish to acknowledge the beam time at the ISA synchrotron
at Aarhus University, Denmark. The research leading to these
results has received funding from the European Community’s
Seventh Framework Programme (Grant No. FP7/2007-2013)
CALIPSO under Grant Agreement No. 312284. D.B.J.
thanks the Australian Research Council for financial support
provided through a Discovery Early Career Research Award.
M.J.B. also thanks the Australian Research Council for some
financial support, while M.J.B. and M.C.A.L. acknowledge the
Brazilian agencies CNPq and FAPEMIG for financial support.
F.B. and G.G. acknowledge partial financial support from the
Spanish Ministry MINECO (Project No. FIS2012-31230) and
the EU COST Action No. CM1301 (CELINA). Finally, R.F.C.,
M.T.do N.V., M.H.F.B., and M.A.P.L. acknowledge support
from the Brazilian agency CNPq.Peer Reviewe
Causality guided machine learning model on wetland CH<sub>4</sub> emissions across global wetlands
Evolution of light-harvesting complex proteins from Chl c-containing algae
<p>Abstract</p> <p>Background</p> <p>Light harvesting complex (LHC) proteins function in photosynthesis by binding chlorophyll (Chl) and carotenoid molecules that absorb light and transfer the energy to the reaction center Chl of the photosystem. Most research has focused on LHCs of plants and chlorophytes that bind Chl <it>a </it>and <it>b </it>and extensive work on these proteins has uncovered a diversity of biochemical functions, expression patterns and amino acid sequences. We focus here on a less-studied family of LHCs that typically bind Chl <it>a </it>and <it>c</it>, and that are widely distributed in Chl <it>c</it>-containing and other algae. Previous phylogenetic analyses of these proteins suggested that individual algal lineages possess proteins from one or two subfamilies, and that most subfamilies are characteristic of a particular algal lineage, but genome-scale datasets had revealed that some species have multiple different forms of the gene. Such observations also suggested that there might have been an important influence of endosymbiosis in the evolution of LHCs.</p> <p>Results</p> <p>We reconstruct a phylogeny of LHCs from Chl <it>c</it>-containing algae and related lineages using data from recent sequencing projects to give ~10-fold larger taxon sampling than previous studies. The phylogeny indicates that individual taxa possess proteins from multiple LHC subfamilies and that several LHC subfamilies are found in distantly related algal lineages. This phylogenetic pattern implies functional differentiation of the gene families, a hypothesis that is consistent with data on gene expression, carotenoid binding and physical associations with other LHCs. In all probability LHCs have undergone a complex history of evolution of function, gene transfer, and lineage-specific diversification.</p> <p>Conclusion</p> <p>The analysis provides a strikingly different picture of LHC diversity than previous analyses of LHC evolution. Individual algal lineages possess proteins from multiple LHC subfamilies. Evolutionary relationships showed support for the hypothesized origin of Chl <it>c </it>plastids. This work also allows recent experimental findings about molecular function to be understood in a broader phylogenetic context.</p
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