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Sample records for transient microbial habitats

  1. Subsurface microbial habitats on Mars

    Science.gov (United States)

    Boston, P. J.; Mckay, C. P.

    1991-01-01

    We developed scenarios for shallow and deep subsurface cryptic niches for microbial life on Mars. Such habitats could have considerably prolonged the persistence of life on Mars as surface conditions became increasingly inhospitable. The scenarios rely on geothermal hot spots existing below the near or deep subsurface of Mars. Recent advances in the comparatively new field of deep subsurface microbiology have revealed previously unsuspected rich aerobic and anaerobic microbal communities far below the surface of the Earth. Such habitats, protected from the grim surface conditions on Mars, could receive warmth from below and maintain water in its liquid state. In addition, geothermally or volcanically reduced gases percolating from below through a microbiologically active zone could provide the reducing power needed for a closed or semi-closed microbial ecosystem to thrive.

  2. Threatened corals provide underexplored microbial habitats.

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    Shinichi Sunagawa

    2010-03-01

    Full Text Available Contemporary in-depth sequencing of environmental samples has provided novel insights into microbial community structures, revealing that their diversity had been previously underestimated. Communities in marine environments are commonly composed of a few dominant taxa and a high number of taxonomically diverse, low-abundance organisms. However, studying the roles and genomic information of these "rare" organisms remains challenging, because little is known about their ecological niches and the environmental conditions to which they respond. Given the current threat to coral reef ecosystems, we investigated the potential of corals to provide highly specialized habitats for bacterial taxa including those that are rarely detected or absent in surrounding reef waters. The analysis of more than 350,000 small subunit ribosomal RNA (16S rRNA sequence tags and almost 2,000 nearly full-length 16S rRNA gene sequences revealed that rare seawater biosphere members are highly abundant or even dominant in diverse Caribbean corals. Closely related corals (in the same genus/family harbored similar bacterial communities. At higher taxonomic levels, however, the similarities of these communities did not correlate with the phylogenetic relationships among corals, opening novel questions about the evolutionary stability of coral-microbial associations. Large proportions of OTUs (28.7-49.1% were unique to the coral species of origin. Analysis of the most dominant ribotypes suggests that many uncovered bacterial taxa exist in coral habitats and await future exploration. Our results indicate that coral species, and by extension other animal hosts, act as specialized habitats of otherwise rare microbes in marine ecosystems. Here, deep sequencing provided insights into coral microbiota at an unparalleled resolution and revealed that corals harbor many bacterial taxa previously not known. Given that two of the coral species investigated are listed as threatened under

  3. Effect of pesticides on microbial communities in container aquatic habitats

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    Mosquitoes develop in a variety of aquatic habitats and feed on microbial communities associated with decaying organic matter. These aquatic habitats are often embedded within and around agricultural lands and are frequently exposed to agricultural chemicals. We used a microcosm approach to examine ...

  4. Destiny of microbial aerosol in confined habitat

    Science.gov (United States)

    Viacheslav, Ilyin; Tikhomirov, Alexander A.; Novikova, Nataliya; Nickolay Manukovsky, D..; Kharin, Sergey; Pasanen, Pertti

    Biomodeling experiment was performed at the Institute of Biophysics in Krasnoyarsk dedicated to modeling the bacterial aerosol behavior in airtight chamber. The experiment was perform an one of workpackages of FP-7 project BIOSMHARS. Bacterial aerosol included particles of bacteria and fungi: Staphylococcus epidermidis, Bacillus licheniformis and Penicillium expansum The experiments allowed the following conclusions: 1. The major trend in air and surface contamination is permanent presence of the microbial factor throughout the time of generation. In the course of generation, level of contamination was gradually dropping except for the upward trend at the end of generation. These patterns were confirmed equally by the results of sedimentation studies and measurements using the Andersen impact 2. Sedimentation of airborne particles containing microbes went on at least two hours after the generation had been finished. However, level of this late sedimentation was approximately 10 folds less as compared with that in the course of generation. 3. Horizontal surfaces appear to be particularly vulnerable loci in airtight rooms. Their contamination was the highest. Levels of their contamination were higher than elsewhere. The closer is the source, the higher the level of contamination. 4. Walls were least contaminated. The ceiling was essentially clean. Air in the vicinity of the ceiling contained microbiota little if any. To summarize, the modeling experiments showed that the microbial component is a permanent resident of airtight rooms no matter decontamination effort (HEPA filters). The gravitational forces ensure that air cleans from microbiota by way of sedimentation. At the same time, together with microparticles microflora accumulates on horizontal surfaces which become the loci of microbes deposition and development. Therefore, despite the system of microbial control, risks of infection still raises the major concern for those who work in airtight facilities

  5. Accounting for microbial habitats in modeling soil organic matter dynamics

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    Chenu, Claire; Garnier, Patricia; Nunan, Naoise; Pot, Valérie; Raynaud, Xavier; Vieublé, Laure; Otten, Wilfred; Falconer, Ruth; Monga, Olivier

    2017-04-01

    The extreme heterogeneity of soils constituents, architecture and inhabitants at the microscopic scale is increasingly recognized. Microbial communities exist and are active in a complex 3-D physical framework of mineral and organic particles defining pores of various sizes, more or less inter-connected. This results in a frequent spatial disconnection between soil carbon, energy sources and the decomposer organisms and a variety of microhabitats that are more or less suitable for microbial growth and activity. However, current biogeochemical models account for C dynamics at the macroscale (cm, m) and consider time- and spatially averaged relationships between microbial activity and soil characteristics. Different modelling approaches have intended to account for this microscale heterogeneity, based either on considering aggregates as surrogates for microbial habitats, or pores. Innovative modelling approaches are based on an explicit representation of soil structure at the fine scale, i.e. at µm to mm scales: pore architecture and their saturation with water, localization of organic resources and of microorganisms. Three recent models are presented here, that describe the heterotrophic activity of either bacteria or fungi and are based upon different strategies to represent the complex soil pore system (Mosaic, LBios and µFun). These models allow to hierarchize factors of microbial activity in soil's heterogeneous architecture. Present limits of these approaches and challenges are presented, regarding the extensive information required on soils at the microscale and to up-scale microbial functioning from the pore to the core scale.

  6. Microbial diversity and metabolic networks in acid mine drainage habitats

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    Celia eMendez-Garcia

    2015-05-01

    Full Text Available Acid mine drainage (AMD emplacements are low-complexity natural systems. Low-pH conditions appear to be the main factor underlying the limited diversity of the microbial populations thriving in these environments, although temperature, ionic composition, total organic carbon and dissolved oxygen are also considered to significantly influence their microbial life. This natural reduction in diversity driven by extreme conditions was reflected in several studies on the microbial populations inhabiting the various micro-environments present in such ecosystems. Early studies based on the physiology of the autochthonous microbiota and the growing success of omics technologies have enabled a better understanding of microbial ecology and function in low-pH mine outflows; however, complementary omics-derived data should be included to completely describe their microbial ecology. Furthermore, recent updates on the distribution of eukaryotes and ultra-micro-archaea demand their inclusion in the microbial characterisation of AMD systems. In this review, we present a complete overview of the bacterial, archaeal (including ultra-micro-archaeal and eukaryotic diversity in these ecosystems and include a thorough depiction of the metabolism and element cycling in AMD habitats. We also review different metabolic network structures at the organismal level, which is necessary to disentangle the role of each member of the AMD communities described thus far.

  7. Linking microbial diversity and functionality of arctic glacial surface habitats.

    Science.gov (United States)

    Lutz, Stefanie; Anesio, Alexandre M; Edwards, Arwyn; Benning, Liane G

    2017-02-01

    Distinct microbial habitats on glacial surfaces are dominated by snow and ice algae, which are the critical players and the dominant primary colonisers and net producers during the melt season. Here for the first time we have evaluated the role of these algae in association with the full microbial community composition (i.e., algae, bacteria, archaea) in distinct surface habitats and on 12 glaciers and permanent snow fields in Svalbard and Arctic Sweden. We cross-correlated these data with the analyses of specific metabolites such as fatty acids and pigments, and a full suite of potential critical physico-chemical parameters including major and minor nutrients, and trace metals. It has been shown that correlations between single algal species, metabolites, and specific geochemical parameters can be used to unravel mixed metabolic signals in complex communities, further assign them to single species and infer their functionality. The data also clearly show that the production of metabolites in snow and ice algae is driven mainly by nitrogen and less so by phosphorus limitation. This is especially important for the synthesis of secondary carotenoids, which cause a darkening of glacial surfaces leading to a decrease in surface albedo and eventually higher melting rates. © 2016 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

  8. Transient habitats limit development time for periodical cicadas.

    Science.gov (United States)

    Karban, Richard

    2014-01-01

    Periodical cicadas (Magicicada spp.) mature in 13 or 17 years, the longest development times for any non-diapausing insects. Selection may favor prolonged development since nymphs experience little mortality and individuals taking 17 years have been shown to have greater fecundity than those taking 13 years. Why don't periodical cicadas take even longer to develop? Nymphs feed on root xylem fluid and move little. Ovipositing females prefer fast-growing trees at forest edges. I hypothesized that (1) adults emerging at edges would be heavier than those from forest interiors and (2) habitat changes could limit development time. I collected newly eclosed females that had neither fed as adults nor moved from their site of development. For M. septendecim, females from edges were 4.9% heavier than those from the interior. I assumed that emergence density indicated habitat quality and measured density at eight sites in 1979, 1996, and 2013. Over three generations, variation in densities was great; densities at two sites crashed, and at one site they exploded to 579/m2 Habitat transience may limit development time because only adults can reassess habitats and reposition offspring. In conclusion, cicadas are affected by habitat characteristics, habitats change over 17 years, and cicadas may emerge, mate, and redistribute their offspring to track habitat dynamics.

  9. Space Use and Habitat Selection by Resident and Transient Red Wolves (Canis rufus.

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    Joseph W Hinton

    Full Text Available Recovery of large carnivores remains a challenge because complex spatial dynamics that facilitate population persistence are poorly understood. In particular, recovery of the critically endangered red wolf (Canis rufus has been challenging because of its vulnerability to extinction via human-caused mortality and hybridization with coyotes (Canis latrans. Therefore, understanding red wolf space use and habitat selection is important to assist recovery because key aspects of wolf ecology such as interspecific competition, foraging, and habitat selection are well-known to influence population dynamics and persistence. During 2009-2011, we used global positioning system (GPS radio-telemetry to quantify space use and 3rd-order habitat selection for resident and transient red wolves on the Albemarle Peninsula of eastern North Carolina. The Albemarle Peninsula was a predominantly agricultural landscape in which red wolves maintained spatially stable home ranges that varied between 25 km2 and 190 km2. Conversely, transient red wolves did not maintain home ranges and traversed areas between 122 km2 and 681 km2. Space use by transient red wolves was not spatially stable and exhibited shifting patterns until residency was achieved by individual wolves. Habitat selection was similar between resident and transient red wolves in which agricultural habitats were selected over forested habitats. However, transients showed stronger selection for edges and roads than resident red wolves. Behaviors of transient wolves are rarely reported in studies of space use and habitat selection because of technological limitations to observed extensive space use and because they do not contribute reproductively to populations. Transients in our study comprised displaced red wolves and younger dispersers that competed for limited space and mating opportunities. Therefore, our results suggest that transiency is likely an important life-history strategy for red wolves that

  10. Space use and habitat selection by resident and transient red wolves (Canis rufus)

    Science.gov (United States)

    Hinton, Joseph W.; Proctor, Christine; Kelly, Marcella J.; van Manen, Frank T.; Vaughan, Michael R.; Chamberlain, Michael J.

    2016-01-01

    Recovery of large carnivores remains a challenge because complex spatial dynamics that facilitate population persistence are poorly understood. In particular, recovery of the critically endangered red wolf (Canis rufus) has been challenging because of its vulnerability to extinction via human-caused mortality and hybridization with coyotes (Canis latrans). Therefore, understanding red wolf space use and habitat selection is important to assist recovery because key aspects of wolf ecology such as interspecific competition, foraging, and habitat selection are well-known to influence population dynamics and persistence. During 2009–2011, we used global positioning system (GPS) radio-telemetry to quantify space use and 3rd-order habitat selection for resident and transient red wolves on the Albemarle Peninsula of eastern North Carolina. The Albemarle Peninsula was a predominantly agricultural landscape in which red wolves maintained spatially stable home ranges that varied between 25 km2 and 190 km2. Conversely, transient red wolves did not maintain home ranges and traversed areas between 122 km2 and 681 km2. Space use by transient red wolves was not spatially stable and exhibited shifting patterns until residency was achieved by individual wolves. Habitat selection was similar between resident and transient red wolves in which agricultural habitats were selected over forested habitats. However, transients showed stronger selection for edges and roads than resident red wolves. Behaviors of transient wolves are rarely reported in studies of space use and habitat selection because of technological limitations to observed extensive space use and because they do not contribute reproductively to populations. Transients in our study comprised displaced red wolves and younger dispersers that competed for limited space and mating opportunities. Therefore, our results suggest that transiency is likely an important life-history strategy for red wolves that facilitates

  11. Space Use and Habitat Selection by Resident and Transient Coyotes (Canis latrans.

    Directory of Open Access Journals (Sweden)

    Joseph W Hinton

    Full Text Available Little information exists on coyote (Canis latrans space use and habitat selection in the southeastern United States and most studies conducted in the Southeast have been carried out within small study areas (e.g., ≤1,000 km2. Therefore, studying the placement, size, and habitat composition of coyote home ranges over broad geographic areas could provide relevant insights regarding how coyote populations adjust to regionally varying ecological conditions. Despite an increasing number of studies of coyote ecology, few studies have assessed the role of transiency as a life-history strategy among coyotes. During 2009-2011, we used GPS radio-telemetry to study coyote space use and habitat selection on the Albemarle Peninsula of northeastern North Carolina. We quantified space use and 2nd- and 3rd-order habitat selection for resident and transient coyotes to describe space use patterns in a predominantly agricultural landscape. The upper limit of coyote home-range size was approximately 47 km2 and coyotes exhibiting shifting patterns of space use of areas >65 km2 were transients. Transients exhibited localized space use patterns for short durations prior to establishing home ranges, which we defined as "biding" areas. Resident and transient coyotes demonstrated similar habitat selection, notably selection of agricultural over forested habitats. However, transients exhibited stronger selection for roads than resident coyotes. Although transient coyotes are less likely to contribute reproductively to their population, transiency may be an important life history trait that facilitates metapopulation dynamics through dispersal and the eventual replacement of breeding residents lost to mortality.

  12. Space use and habitat selection by resident and transient coyotes (Canis latrans)

    Science.gov (United States)

    Hinton, Joseph W; van Manen, Frank T.; Chamberlain, Michael J

    2015-01-01

    Little information exists on coyote (Canis latrans) space use and habitat selection in the southeastern United States and most studies conducted in the Southeast have been carried out within small study areas (e.g., ≤1,000 km2). Therefore, studying the placement, size, and habitat composition of coyote home ranges over broad geographic areas could provide relevant insights regarding how coyote populations adjust to regionally varying ecological conditions. Despite an increasing number of studies of coyote ecology, few studies have assessed the role of transiency as a life-history strategy among coyotes. During 2009–2011, we used GPS radio-telemetry to study coyote space use and habitat selection on the Albemarle Peninsula of northeastern North Carolina. We quantified space use and 2nd- and 3rd-order habitat selection for resident and transient coyotes to describe space use patterns in a predominantly agricultural landscape. The upper limit of coyote home-range size was approximately 47 km2 and coyotes exhibiting shifting patterns of space use of areas >65 km2 were transients. Transients exhibited localized space use patterns for short durations prior to establishing home ranges, which we defined as “biding” areas. Resident and transient coyotes demonstrated similar habitat selection, notably selection of agricultural over forested habitats. However, transients exhibited stronger selection for roads than resident coyotes. Although transient coyotes are less likely to contribute reproductively to their population, transiency may be an important life history trait that facilitates metapopulation dynamics through dispersal and the eventual replacement of breeding residents lost to mortality.

  13. Limited recovery of soil microbial activity after transient exposure to gasoline vapors

    DEFF Research Database (Denmark)

    Modrzyński, Jakub J.; Christensen, Jan H.; Mayer, Philipp

    2016-01-01

    During gasoline spills complex mixtures of toxic volatile organic compounds (VOCs) are released to terrestrial environments. Gasoline VOCs exert baseline toxicity (narcosis) and may thus broadly affect soil biota. We assessed the functional resilience (i.e. resistance and recovery of microbial...... functions) in soil microbial communities transiently exposed to gasoline vapors by passive dosing via headspace for 40 days followed by a recovery phase of 84 days. Chemical exposure was characterized with GC-MS, whereas microbial activity was monitored as soil respiration (CO2 release) and soil bacterial...... microbial activity indicating residual soil toxicity, which could not be attributed to BTEX, but rather to mixture toxicity of more persistent gasoline constituents or degradation products. Our results indicate a limited potential for functional recovery of soil microbial communities after transient...

  14. Habitat constraints on the functional significance of soil microbial communities

    Science.gov (United States)

    Nunan, Naoise; Leloup, Julie; Ruamps, Léo; Pouteau, Valérie; Chenu, Claire

    2017-04-01

    An underlying assumption of most ecosystem models is that soil microbial communities are functionally equivalent; in other words, that microbial activity under given set of conditions is not dependent on the composition or diversity of the communities. Although a number of studies have suggested that this assumption is incorrect, ecosystem models can adequately describe ecosystem processes, such as soil C dynamics, without an explicit description of microbial functioning. Here, we provide a mechanistic basis for reconciling this apparent discrepancy. In a reciprocal transplant experiment, we show that microbial communities are not always functionally equivalent. The data suggest that when the supply of substrate is restricted, then the functioning of different microbial communities cannot be distinguished, but when the supply is less restricted, the intrinsic functional differences among communities can be expressed. When the supply of C is restricted then C dynamics are related to the properties of the physical and chemical environment of the soil. We conclude that soil C dynamics may depend on microbial community structure or diversity in environments such as the rhizosphere or the litter layer, but are less likely to do so in oligotrophic environments such as the mineral layers of soil.

  15. Transitory microbial habitat in the hyperarid Atacama Desert

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    Schulze-Makuch, Dirk; Wagner, Dirk; Kounaves, Samuel P.; Mangelsdorf, Kai; Devine, Kevin G.; de Vera, Jean-Pierre; Schmitt-Kopplin, Philippe; Grossart, Hans-Peter; Parro, Victor; Kaupenjohann, Martin; Galy, Albert; Schneider, Beate; Airo, Alessandro; Frösler, Jan; Davila, Alfonso F.; Arens, Felix L.; Cáceres, Luis; Solís Cornejo, Francisco; Carrizo, Daniel; Dartnell, Lewis; DiRuggiero, Jocelyne; Flury, Markus; Ganzert, Lars; Gessner, Mark O.; Grathwohl, Peter; Guan, Lisa; Heinz, Jacob; Hess, Matthias; Keppler, Frank; Maus, Deborah; McKay, Christopher P.; Meckenstock, Rainer U.; Montgomery, Wren; Oberlin, Elizabeth A.; Probst, Alexander J.; Sáenz, Johan S.; Sattler, Tobias; Schirmack, Janosch; Sephton, Mark A.; Schloter, Michael; Uhl, Jenny; Valenzuela, Bernardita; Vestergaard, Gisle; Wörmer, Lars; Zamorano, Pedro

    2018-03-01

    Traces of life are nearly ubiquitous on Earth. However, a central unresolved question is whether these traces always indicate an active microbial community or whether, in extreme environments, such as hyperarid deserts, they instead reflect just dormant or dead cells. Although microbial biomass and diversity decrease with increasing aridity in the Atacama Desert, we provide multiple lines of evidence for the presence of an at times metabolically active, microbial community in one of the driest places on Earth. We base this observation on four major lines of evidence: (i) a physico-chemical characterization of the soil habitability after an exceptional rain event, (ii) identified biomolecules indicative of potentially active cells [e.g., presence of ATP, phospholipid fatty acids (PLFAs), metabolites, and enzymatic activity], (iii) measurements of in situ replication rates of genomes of uncultivated bacteria reconstructed from selected samples, and (iv) microbial community patterns specific to soil parameters and depths. We infer that the microbial populations have undergone selection and adaptation in response to their specific soil microenvironment and in particular to the degree of aridity. Collectively, our results highlight that even the hyperarid Atacama Desert can provide a habitable environment for microorganisms that allows them to become metabolically active following an episodic increase in moisture and that once it decreases, so does the activity of the microbiota. These results have implications for the prospect of life on other planets such as Mars, which has transitioned from an earlier wetter environment to today’s extreme hyperaridity.

  16. Synthetic Microbial Ecology: Engineering Habitats for Modular Consortia.

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    Ben Said, Sami; Or, Dani

    2017-01-01

    The metabolic diversity present in microbial communities enables cooperation toward accomplishing more complex tasks than possible by a single organism. Members of a consortium communicate by exchanging metabolites or signals that allow them to coordinate their activity through division of labor. In contrast with monocultures, evidence suggests that microbial consortia self-organize to form spatial patterns, such as observed in biofilms or in soil aggregates, that enable them to respond to gradient, to improve resource interception and to exchange metabolites more effectively. Current biotechnological applications of microorganisms remain rudimentary, often relying on genetically engineered monocultures (e.g., pharmaceuticals) or mixed-cultures of partially known composition (e.g., wastewater treatment), yet the vast potential of "microbial ecological power" observed in most natural environments, remains largely underused. In line with the Unified Microbiome Initiative (UMI) which aims to "discover and advance tools to understand and harness the capabilities of Earth's microbial ecosystems," we propose in this concept paper to capitalize on ecological insights into the spatial and modular design of interlinked microbial consortia that would overcome limitations of natural systems and attempt to optimize the functionality of the members and the performance of the engineered consortium. The topology of the spatial connections linking the various members and the regulated fluxes of media between those modules, while representing a major engineering challenge, would allow the microbial species to interact. The modularity of such spatially linked microbial consortia (SLMC) could facilitate the design of scalable bioprocesses that can be incorporated as parts of a larger biochemical network. By reducing the need for a compatible growth environment for all species simultaneously, SLMC will dramatically expand the range of possible combinations of microorganisms and their

  17. Build your own soil: exploring microfluidics to create microbial habitat structures

    Science.gov (United States)

    Aleklett, Kristin; Kiers, E Toby; Ohlsson, Pelle; Shimizu, Thomas S; Caldas, Victor EA; Hammer, Edith C

    2018-01-01

    Soil is likely the most complex ecosystem on earth. Despite the global importance and extraordinary diversity of soils, they have been notoriously challenging to study. We show how pioneering microfluidic techniques provide new ways of studying soil microbial ecology by allowing simulation and manipulation of chemical conditions and physical structures at the microscale in soil model habitats. PMID:29135971

  18. Microbial community composition of transiently wetted Antarctic Dry Valley soils.

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    Niederberger, Thomas D; Sohm, Jill A; Gunderson, Troy E; Parker, Alexander E; Tirindelli, Joëlle; Capone, Douglas G; Carpenter, Edward J; Cary, Stephen C

    2015-01-01

    During the summer months, wet (hyporheic) soils associated with ephemeral streams and lake edges in the Antarctic Dry Valleys (DVs) become hotspots of biological activity and are hypothesized to be an important source of carbon and nitrogen for arid DV soils. Recent research in the DV has focused on the geochemistry and microbial ecology of lakes and arid soils, with substantially less information being available on hyporheic soils. Here, we determined the unique properties of hyporheic microbial communities, resolved their relationship to environmental parameters and compared them to archetypal arid DV soils. Generally, pH increased and chlorophyll a concentrations decreased along transects from wet to arid soils (9.0 to ~7.0 for pH and ~0.8 to ~5 μg/cm(3) for chlorophyll a, respectively). Soil water content decreased to below ~3% in the arid soils. Community fingerprinting-based principle component analyses revealed that bacterial communities formed distinct clusters specific to arid and wet soils; however, eukaryotic communities that clustered together did not have similar soil moisture content nor did they group together based on sampling location. Collectively, rRNA pyrosequencing indicated a considerably higher abundance of Cyanobacteria in wet soils and a higher abundance of Acidobacterial, Actinobacterial, Deinococcus/Thermus, Bacteroidetes, Firmicutes, Gemmatimonadetes, Nitrospira, and Planctomycetes in arid soils. The two most significant differences at the genus level were Gillisia signatures present in arid soils and chloroplast signatures related to Streptophyta that were common in wet soils. Fungal dominance was observed in arid soils and Viridiplantae were more common in wet soils. This research represents an in-depth characterization of microbial communities inhabiting wet DV soils. Results indicate that the repeated wetting of hyporheic zones has a profound impact on the bacterial and eukaryotic communities inhabiting in these areas.

  19. A submarine volcanic eruption leads to a novel microbial habitat.

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    Danovaro, Roberto; Canals, Miquel; Tangherlini, Michael; Dell'Anno, Antonio; Gambi, Cristina; Lastras, Galderic; Amblas, David; Sanchez-Vidal, Anna; Frigola, Jaime; Calafat, Antoni M; Pedrosa-Pàmies, Rut; Rivera, Jesus; Rayo, Xavier; Corinaldesi, Cinzia

    2017-04-24

    Submarine volcanic eruptions are major catastrophic events that allow investigation of the colonization mechanisms of newly formed seabed. We explored the seafloor after the eruption of the Tagoro submarine volcano off El Hierro Island, Canary Archipelago. Near the summit of the volcanic cone, at about 130 m depth, we found massive mats of long, white filaments that we named Venus's hair. Microscopic and molecular analyses revealed that these filaments are made of bacterial trichomes enveloped within a sheath and colonized by epibiotic bacteria. Metagenomic analyses of the filaments identified a new genus and species of the order Thiotrichales, Thiolava veneris. Venus's hair shows an unprecedented array of metabolic pathways, spanning from the exploitation of organic and inorganic carbon released by volcanic degassing to the uptake of sulfur and nitrogen compounds. This unique metabolic plasticity provides key competitive advantages for the colonization of the new habitat created by the submarine eruption. A specialized and highly diverse food web thrives on the complex three-dimensional habitat formed by these microorganisms, providing evidence that Venus's hair can drive the restart of biological systems after submarine volcanic eruptions.

  20. The Universe: a Cryogenic Habitat for Microbial Life

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    Wickramasinghe, Chandra

    Panspermia, an ancient idea, posits that microbial life is ubiquitous in the Universe. After several decades of almost irrational rejection, panspermia is at last coming to be regarded as a serious contender for the beginnings of life on our planet. Astronomical data is shown to be consistent with the widespread distribution of complex organic molecules and dust particles that may have a biological provenance. A minuscule (10-21) survival rate of freeze-dried bacteria in space is all that is needed to ensure the continual recycling of cosmic microbial life in the galaxy. Evidence that terrestrial life may have come from elsewhere in the solar system has accumulated over the past decade. Mars is seen by some as a possible source of terrestrial life, but some hundreds of billions of comets that enveloped the entire solar system, are a far more likely primordial reservoir of life. Comets would then have seeded Earth, Mars, and indeed all other habitable planetary bodies in the inner regions of the solar system. The implications of this point of view, which was developed in conjunction with the late Sir Fred Hoyle since the 1970's, are now becoming amenable to direct empirical test by studies of pristine organic material in the stratosphere. The ancient theory of panspermia may be on the verge of vindication, in which case the entire universe would be a grand crucible of cryomicrobiology.

  1. Routine habitat change: a source of unrecognized transient alteration of intestinal microbiota in laboratory mice.

    Science.gov (United States)

    Ma, Betty W; Bokulich, Nicholas A; Castillo, Patricia A; Kananurak, Anchasa; Underwood, Mark A; Mills, David A; Bevins, Charles L

    2012-01-01

    The mammalian intestine harbors a vast, complex and dynamic microbial population, which has profound effects on host nutrition, intestinal function and immune response, as well as influence on physiology outside of the alimentary tract. Imbalance in the composition of the dense colonizing bacterial population can increase susceptibility to various acute and chronic diseases. Valuable insights on the association of the microbiota with disease critically depend on investigation of mouse models. Like in humans, the microbial community in the mouse intestine is relatively stable and resilient, yet can be influenced by environmental factors. An often-overlooked variable in research is basic animal husbandry, which can potentially alter mouse physiology and experimental outcomes. This study examined the effects of common husbandry practices, including food and bedding alterations, as well as facility and cage changes, on the gut microbiota over a short time course of five days using three culture-independent techniques, quantitative PCR, terminal restriction fragment length polymorphism (TRFLP) and next generation sequencing (NGS). This study detected a substantial transient alteration in microbiota after the common practice of a short cross-campus facility transfer, but found no comparable alterations in microbiota within 5 days of switches in common laboratory food or bedding, or following an isolated cage change in mice acclimated to their housing facility. Our results highlight the importance of an acclimation period following even simple transfer of mice between campus facilities, and highlights that occult changes in microbiota should be considered when imposing husbandry variables on laboratory animals.

  2. In vitro anticancer activity of microbial isolates from diverse habitats

    Directory of Open Access Journals (Sweden)

    Angel Treasa Thomas

    2011-06-01

    Full Text Available Extracts from natural products, especially microorganisms, have served as a valuable source of diverse molecules in many drug discovery efforts and led to the discovery of several important drugs. Identification of microbial strains having promising biological activities and purifying the bio-molecules responsible for the activities, have led to the discovery of many bioactive molecules. Extracellular, as well as intracellular, extracts of the metabolites of thirty-six bacterial and twenty-four fungal isolates, grown under unusual conditions such as high temperature, high salt and low sugar concentrations, were in vitro tested for their cytotoxic potential on various cancer cell lines. The extracts were screened on HeLa and MCF-7 cell lines to study the cytotoxic potential. Nuclear staining and flow cytometric studies were carried out to assess the potential of the extracts in arresting the cell cycle. The crude ethylacetate extract of isolate F-21 showed promising results by MTT assay with IC50 as low as 20.37±0.36 µg/mL on HeLa, and 44.75±0.81 µg/mL on MCF-7 cells, comparable with Cisplatin. The isolate F-21 was identified as Aspergillus sp. Promising results were also obtained with B-2C and B-4E strains. Morphological studies, biochemical tests and preliminary chemical investigation of the extracts were also carried out.Extratos de produtos naturais, especialmente de microrganismos, constituíram-se em fonte valiosa de diversas moléculas em muitas descobertas de fármacos e levaram à descoberta de fármacos importantes. A identificação de espécies microbianas que apresentam atividade biológica e a purificação de biomoléculas responsáveis pelas atividades levou à descoberta de muitas moléculas bioativas. Extratos extracelulares tanto quanto intracelulares de metabólitos de 36 isolados de bactérias e 24 isolados de fungos, que cresceram sob condições não usuais, como alta temperatura, alta concentração de sal e baixa

  3. Resolution of habitat-associated ecogenomic signatures in bacteriophage genomes and application to microbial source tracking.

    Science.gov (United States)

    Ogilvie, Lesley A; Nzakizwanayo, Jonathan; Guppy, Fergus M; Dedi, Cinzia; Diston, David; Taylor, Huw; Ebdon, James; Jones, Brian V

    2018-04-01

    Just as the expansion in genome sequencing has revealed and permitted the exploitation of phylogenetic signals embedded in bacterial genomes, the application of metagenomics has begun to provide similar insights at the ecosystem level for microbial communities. However, little is known regarding this aspect of bacteriophage associated with microbial ecosystems, and if phage encode discernible habitat-associated signals diagnostic of underlying microbiomes. Here we demonstrate that individual phage can encode clear habitat-related 'ecogenomic signatures', based on relative representation of phage-encoded gene homologues in metagenomic data sets. Furthermore, we show the ecogenomic signature encoded by the gut-associated ɸB124-14 can be used to segregate metagenomes according to environmental origin, and distinguish 'contaminated' environmental metagenomes (subject to simulated in silico human faecal pollution) from uncontaminated data sets. This indicates phage-encoded ecological signals likely possess sufficient discriminatory power for use in biotechnological applications, such as development of microbial source tracking tools for monitoring water quality.

  4. Investigating Microbial Habitats in Hydrothermal Chimneys using Ti-Thermocouple Arrays: Microbial Diversity

    Science.gov (United States)

    Pagé, A.; Tivey, M. K.; Stakes, D. S.; Bradley, A. M.; Seewald, J. S.; Wheat, C. G.; Reysenbach, A.

    2004-12-01

    In order to examine the changes that occur in the microbial community composition as a deep-sea hydrothermal vent chimney develops, we deployed Ti-thermocouple arrays over high temperature vents at two active sites of the Guaymas Basin Southern Trough. Chimney material that precipitated around the arrays was recovered after 4 and 72 days. Chimney material that precipitated prior to deployment of the arrays was also recovered at one of the sites (Busted Shroom). Culture-independent analysis based on the small subunit rRNA sequence (cloning and DGGE) was used to determine the microbial diversity associated with subsamples of each chimney. The original Busted Shroom chimney (BSO) was dominated by members of the Crenarchaeota Marine Group I, a group of cosmopolitan marine Archaea, ɛ -Proteobacteria, and γ -Proteobacteria, two divisions of Bacteria that are common to deep-sea vents. The 4 days old Busted Shroom chimney (BSD1) was dominated by members of the Methanocaldococcaceae, hyperthermophilic methanogens, and the 72 days old chimney (BSD2) by members of the Methanosarcinaceae, mesophilic and thermophilic methanogens. At the second site, Toadstool, the 72 days old chimney material that had precipitated around the array (TS) revealed the dominance of sequences from uncultured marine Archaea, the DHVE group I and II, and from the ɛ -Proteobacteria. Additionally, sequences belonging to the Methanocaldococcaceae and Desulfurococcaceae were recovered next to thermocouples that were at temperatures of 109° C (at Busted Shroom) and 116° C (at Toadstool), respectively. These temperatures are higher than the upper limit for growth of cultured representatives from each family.

  5. Habitat Fragmentation can Modulate Drought Effects on the Plant-soil-microbial System in Mediterranean Holm Oak (Quercus ilex) Forests.

    Science.gov (United States)

    Flores-Rentería, Dulce; Curiel Yuste, Jorge; Rincón, Ana; Brearley, Francis Q; García-Gil, Juan Carlos; Valladares, Fernando

    2015-05-01

    Ecological transformations derived from habitat fragmentation have led to increased threats to above-ground biodiversity. However, the impacts of forest fragmentation on soils and their microbial communities are not well understood. We examined the effects of contrasting fragment sizes on the structure and functioning of soil microbial communities from holm oak forest patches in two bioclimatically different regions of Spain. We used a microcosm approach to simulate the annual summer drought cycle and first autumn rainfall (rewetting), evaluating the functional response of a plant-soil-microbial system. Forest fragment size had a significant effect on physicochemical characteristics and microbial functioning of soils, although the diversity and structure of microbial communities were not affected. The response of our plant-soil-microbial systems to drought was strongly modulated by the bioclimatic conditions and the fragment size from where the soils were obtained. Decreasing fragment size modulated the effects of drought by improving local environmental conditions with higher water and nutrient availability. However, this modulation was stronger for plant-soil-microbial systems built with soils from the northern region (colder and wetter) than for those built with soils from the southern region (warmer and drier) suggesting that the responsiveness of the soil-plant-microbial system to habitat fragmentation was strongly dependent on both the physicochemical characteristics of soils and the historical adaptation of soil microbial communities to specific bioclimatic conditions. This interaction challenges our understanding of future global change scenarios in Mediterranean ecosystems involving drier conditions and increased frequency of forest fragmentation.

  6. Volcano-ice interaction as a microbial habitat on Earth and Mars.

    Science.gov (United States)

    Cousins, Claire R; Crawford, Ian A

    2011-09-01

    Volcano-ice interaction has been a widespread geological process on Earth that continues to occur to the present day. The interaction between volcanic activity and ice can generate substantial quantities of liquid water, together with steep thermal and geochemical gradients typical of hydrothermal systems. Environments available for microbial colonization within glaciovolcanic systems are wide-ranging and include the basaltic lava edifice, subglacial caldera meltwater lakes, glacier caves, and subsurface hydrothermal systems. There is widespread evidence of putative volcano-ice interaction on Mars throughout its history and at a range of latitudes. Therefore, it is possible that life on Mars may have exploited these habitats, much in the same way as has been observed on Earth. The sedimentary and mineralogical deposits resulting from volcano-ice interaction have the potential to preserve evidence of any indigenous microbial populations. These include jökulhlaup (subglacial outflow) sedimentary deposits, hydrothermal mineral deposits, basaltic lava flows, and subglacial lacustrine deposits. Here, we briefly review the evidence for volcano-ice interactions on Mars and discuss the geomicrobiology of volcano-ice habitats on Earth. In addition, we explore the potential for the detection of these environments on Mars and any biosignatures these deposits may contain.

  7. Microbial community diversity and composition varies with habitat characteristics and biofilm function in macrophyte-rich streams

    DEFF Research Database (Denmark)

    Levi, Peter S.; Starnawski, Piotr; Poulsen, Britta

    2017-01-01

    Biofilms in streams play an integral role in ecosystem processes and function yet few studies have investigated the broad diversity of these complex prokaryotic and eukaryotic microbial communities. Physical habitat characteristics can affect the composition and abundance of microorganisms...... in these biofilms by creating microhabitats. Here we describe the prokaryotic and eukaryotic microbial diversity of biofilms in sand and macrophyte habitats (i.e. epipsammon and epiphyton, respectively) in five macrophyte-rich streams in Jutland, Denmark. The macrophyte species varied in growth morphology, C......:N stoichiometry, and preferred stream habitat, providing a range in environmental conditions for the epiphyton. Among all habitats and streams, the prokaryotic communities were dominated by common phyla, including Alphaproteobacteria, Bacteriodetes, and Gammaproteobacteria, while the eukaryotic communities were...

  8. Inter-domain microbial diversity within the coral holobiont Siderastrea siderea from two depth habitats

    Directory of Open Access Journals (Sweden)

    Guido Bonthond

    2018-02-01

    Full Text Available Corals host diverse microbial communities that are involved in acclimatization, pathogen defense, and nutrient cycling. Surveys of coral-associated microbes have been particularly directed toward Symbiodinium and bacteria. However, a holistic understanding of the total microbiome has been hindered by a lack of analyses bridging taxonomically disparate groups. Using high-throughput amplicon sequencing, we simultaneously characterized the Symbiodinium, bacterial, and fungal communities associated with the Caribbean coral Siderastrea siderea collected from two depths (17 and 27 m on Conch reef in the Florida Keys. S. siderea hosted an exceptionally diverse Symbiodinium community, structured differently between sampled depth habitats. While dominated at 27 m by a Symbiodinium belonging to clade C, at 17 m S. siderea primarily hosted a mixture of clade B types. Most fungal operational taxonomic units were distantly related to available reference sequences, indicating the presence of a high degree of fungal novelty within the S. siderea holobiont and a lack of knowledge on the diversity of fungi on coral reefs. Network analysis showed that co-occurrence patterns in the S. siderea holobiont were prevalent among bacteria, however, also detected between fungi and bacteria. Overall, our data show a drastic shift in the associated Symbiodinium community between depths on Conch Reef, which might indicate that alteration in this community is an important mechanism facilitating local physiological adaptation of the S. siderea holobiont. In contrast, bacterial and fungal communities were not structured differently between depth habitats.

  9. Implications of Extracellular Polymeric Substance Matrices of Microbial Habitats Associated with Coastal Aquaculture Systems

    Directory of Open Access Journals (Sweden)

    Juan Carlos Camacho-Chab

    2016-08-01

    Full Text Available Coastal zones support fisheries that provide food for humans and feed for animals. The decline of fisheries worldwide has fostered the development of aquaculture. Recent research has shown that extracellular polymeric substances (EPS synthesized by microorganisms contribute to sustainable aquaculture production, providing feed to the cultured species, removing waste and contributing to the hygiene of closed systems. As ubiquitous components of coastal microbial habitats at the air–seawater and seawater–sediment interfaces as well as of biofilms and microbial aggregates, EPS mediate deleterious processes that affect the performance and productivity of aquaculture facilities, including biofouling of marine cages, bioaccumulation and transport of pollutants. These biomolecules may also contribute to the persistence of harmful algal blooms (HABs and their impact on cultured species. EPS may also exert a positive influence on aquaculture activity by enhancing the settling of aquaculturally valuable larvae and treating wastes in bioflocculation processes. EPS display properties that may have biotechnological applications in the aquaculture industry as antiviral agents and immunostimulants and as a novel source of antifouling bioproducts.

  10. Simple measures of channel habitat complexity predict transient hydraulic storage in streams

    Science.gov (United States)

    Stream thalweg depth profiles (along path of greatest channel depth) and woody debris tallies have recently become components of routine field procedures for quantifying physical habitat in national stream monitoring efforts. Mean residual depth, standard deviation of thalweg dep...

  11. Performance enhancement of microbial fuel cell by applying transient-state regulation

    International Nuclear Information System (INIS)

    Liang, Peng; Zhang, Changyong; Jiang, Yong; Bian, Yanhong; Zhang, Helan; Sun, Xueliang; Yang, Xufei; Zhang, Xiaoyuan; Huang, Xia

    2017-01-01

    Highlights: • MFC was operated with transient-state regulation to enhance its performance. • Effects of the TSR parameters on MFC performance were thoroughly investigated. • Long-term operation of MFC in TSR mode allowed 32.7% higher power production. • Anode capacitance helped reduce the MFC’s internal impedance in the TSR mode. - Abstract: A binder-free, pseudocapacitive anode was fabricated by coating reduced graphene oxide (rGO) and manganese oxide (MnO_2) nanoparticles on stainless steel fibre felt (SS). Microbial fuel cell (MFC) equipped with this novel anode yielded a maximum power density of 1045 mW m"−"2, 20 times higher than that of a similar MFC with a bare SS anode (46 mW m"−"2). Transient-state regulation (TSR) was implemented to further improve the MFC’s power generation. The optimal TSR duty cycle ranged from 67% to 95%, and the MFC’s power density increased with TSR frequency. A maximum power density output of 1238 mW m"−"2 was achieved at the TSR duty cycle of 75% and the frequency of 1 Hz, 18.4% greater than that obtained from the steady state operation. The TSR mode delivered better MFC performance especially when the external resistance was small. Long-term operation tests revealed that the current density and power density yielded in the TSR mode were on average 15.0% and 32.7% greater than those in the steady state mode, respectively. The TSR mode was believed to reduce the internal resistance of the MFC while enhance substrate mass transfer and electron transfer within the anode matrix, thereby improving the MFC performance.

  12. Nematode-associated microbial taxa do not correlate with host phylogeny, geographic region or feeding morphology in marine sediment habitats.

    Science.gov (United States)

    Schuelke, Taruna; Pereira, Tiago José; Hardy, Sarah M; Bik, Holly M

    2018-04-01

    Studies of host-associated microbes are critical for advancing our understanding of ecology and evolution across diverse taxa and ecosystems. Nematode worms are ubiquitous across most habitats on earth, yet little is known about host-associated microbial assemblages within the phylum. Free-living nematodes are globally abundant and diverse in marine sediments, with species exhibiting distinct buccal cavity (mouth) morphologies that are thought to play an important role in feeding ecology and life history strategies. Here, we investigated patterns in marine nematode microbiomes, by characterizing host-associated microbial taxa in 281 worms isolated from a range of habitat types (deep-sea, shallow water, methane seeps, Lophelia coral mounds, kelp holdfasts) across three distinct geographic regions (Arctic, Southern California and Gulf of Mexico). Microbiome profiles were generated from single worms spanning 33 distinct morphological genera, using a two-gene metabarcoding approach to amplify the V4 region of the 16S ribosomal RNA (rRNA) gene targeting bacteria/archaea and the V1-V2 region of the 18S rRNA gene targeting microbial eukaryotes. Contrary to our expectations, nematode microbiome profiles demonstrated no distinct patterns either globally (across depths and ocean basins) or locally (within site); prokaryotic and eukaryotic microbial assemblages did not correlate with nematode feeding morphology, host phylogeny or morphological identity, ocean region or marine habitat type. However, fine-scale analysis of nematode microbiomes revealed a variety of novel ecological interactions, including putative parasites and symbionts, and potential associations with bacterial/archaeal taxa involved in nitrogen and methane cycling. Our results suggest that in marine habitats, free-living nematodes may utilize diverse and generalist foraging strategies that are not correlated with host genotype or feeding morphology. Furthermore, some abiotic factors such as geographic region

  13. Microbial habitat connectivity across spatial scales and hydrothermal temperature gradients at Guaymas Basin

    Directory of Open Access Journals (Sweden)

    Stefanie eMeyer

    2013-07-01

    Full Text Available The Guaymas Basin (Gulf of California hydrothermal vent area is known as a dynamic and hydrothermally vented sedimentary system, where the advection and production of a variety of different metabolic substrates support a high microbial diversity and activity in the seafloor. The main objective of our study was to explore the role of temperature and other environmental factors on community diversity, such as the presence of microbial mats and seafloor bathymetry within one hydrothermally vented field of 200 × 250 m dimension. In this field, temperature increased strongly with sediment depth reaching the known limit to life within a few decimeters. Potential sulfate reduction rate as a key community activity parameter was strongly affected by in situ temperature and sediment depth, declining from high rates of 1-5 μmol ml-1 d-1 at the surface to the detection limit below 5 cm sediment depth, despite the presence of sulfate and hydrocarbons. Automated Ribosomal Intergenic Spacer Analysis yielded a high-resolution fingerprint of the dominant members of the bacterial community. Our analyses showed strong temperature and sediment depth effects on bacterial cell abundance and Operational Taxonomic Units (OTUs number, both declining by more than one order of magnitude below the top 5 cm of the sediment surface. Another fraction of the variation in diversity and community structure was explained by differences in the local bathymetry and spatial position within the vent field. Nevertheless, more than 80% of all detected OTUs were shared among the different temperature realms and sediment depths, after being classified as cold (T<10°C, medium (10°C≤T<40°C or hot (T≥40°C temperature conditions, with significant OTU overlap with the richer surface communities. Overall, this indicates a high connectivity of benthic bacterial habitats in this dynamic and heterogeneous marine ecosystem influenced by strong hydrothermalism.

  14. Microbial Biofilm Community Variation in Flowing Habitats: Potential Utility as Bioindicators of Postmortem Submersion Intervals

    Directory of Open Access Journals (Sweden)

    Jennifer M. Lang

    2016-01-01

    Full Text Available Biofilms are a ubiquitous formation of microbial communities found on surfaces in aqueous environments. These structures have been investigated as biomonitoring indicators for stream heath, and here were used for the potential use in forensic sciences. Biofilm successional development has been proposed as a method to determine the postmortem submersion interval (PMSI of remains because there are no standard methods for estimating the PMSI and biofilms are ubiquitous in aquatic habitats. We sought to compare the development of epinecrotic (biofilms on Sus scrofa domesticus carcasses and epilithic (biofilms on unglazed ceramic tiles communities in two small streams using bacterial automated ribosomal intergenic spacer analysis. Epinecrotic communities were significantly different from epilithic communities even though environmental factors associated with each stream location also had a significant influence on biofilm structure. All communities at both locations exhibited significant succession suggesting that changing communities throughout time is a general characteristic of stream biofilm communities. The implications resulting from this work are that epinecrotic communities have distinctive shifts at the first and second weeks, and therefore the potential to be used in forensic applications by associating successional changes with submersion time to estimate a PMSI. The influence of environmental factors, however, indicates the lack of a successional pattern with the same organisms and a focus on functional diversity may be more applicable in a forensic context.

  15. In situ Dynamics of O2, pH, Light, and Photosynthesis in Ikaite Tufa Columns (Ikka Fjord, Greenland)?A Unique Microbial Habitat

    OpenAIRE

    Trampe, Erik C. L.; Larsen, Jens E. N.; Glaring, Mikkel A.; Stougaard, Peter; K?hl, Michael

    2016-01-01

    The Ikka Fjord (SW Greenland) harbors a unique microbial habitat in the form of several hundred submarine tufa columns composed of ikaite, a special hexahydrate form of calcium carbonate that precipitates when alkaline phosphate- and carbonate-enriched spring water seeping out of the sea floor meets cold seawater. While several unique heterotrophic microbes have been isolated from the tufa columns, the microbial activity, and the boundary conditions for microbial growth in ikaite have remaine...

  16. Colonization Habitat Controls Biomass, Composition, and Metabolic Activity of Attached Microbial Communities in the Columbia River Hyporheic Corridor

    Energy Technology Data Exchange (ETDEWEB)

    Stern, Noah; Ginder-Vogel, Matthew; Stegen, James C.; Arntzen, Evan; Kennedy, David W.; Larget, Bret R.; Roden, Eric E.; Kostka, Joel E.

    2017-06-09

    Hydrologic exchange plays a critical role in biogeochemical cycling within the hyporheic zone (the interface between river water and groundwater) of riverine ecosystems. Such exchange may set limits on the rates of microbial metabolism and impose deterministic selection on microbial communities that adapt to dynamically changing dissolved organic carbon (DOC) sources. This study examined the response of attached microbial communities (in situcolonized sand packs) from groundwater, hyporheic, and riverbed habitats within the Columbia River hyporheic corridor to “cross-feeding” with either groundwater, river water, or DOC-free artificial fluids. Our working hypothesis was that deterministic selection duringin situcolonization would dictate the response to cross-feeding, with communities displaying maximal biomass and respiration when supplied with their native fluid source. In contrast to expectations, the major observation was that the riverbed colonized sand had much higher biomass and respiratory activity, as well as a distinct community structure, compared with those of the hyporheic and groundwater colonized sands. 16S rRNA gene amplicon sequencing revealed a much higher proportion of certain heterotrophic taxa as well as significant numbers of eukaryotic algal chloroplasts in the riverbed colonized sand. Significant quantities of DOC were released from riverbed sediment and colonized sand, and separate experiments showed that the released DOC stimulated respiration in the groundwater and piezometer colonized sand. These results suggest that the accumulation and degradation of labile particulate organic carbon (POC) within the riverbed are likely to release DOC, which may enter the hyporheic corridor during hydrologic exchange, thereby stimulating microbial activity and imposing deterministic selective pressure on the microbial community composition.

    IMPORTANCEThe influence of river water

  17. Microbial abundance on the eggs of a passerine bird and related fitness consequences between urban and rural habitats.

    Science.gov (United States)

    Lee, Sang-Im; Lee, Hyunna; Jablonski, Piotr G; Choe, Jae Chun; Husby, Magne

    2017-01-01

    Urban environments present novel and challenging habitats to wildlife. In addition to well-known difference in abiotic factors between rural and urban environments, the biotic environment, including microbial fauna, may also differ significantly. In this study, we aimed to compare the change in microbial abundance on eggshells during incubation between urban and rural populations of a passerine bird, the Eurasian Magpie (Pica pica), and examine the consequences of any differences in microbial abundances in terms of hatching success and nestling survival. Using real-time PCR, we quantified the abundances of total bacteria, Escherichia coli/Shigella spp., surfactin-producing Bacillus spp. and Candida albicans on the eggshells of magpies. We found that urban magpie eggs harboured greater abundances of E. coli/Shigella spp. and C. albicans before incubation than rural magpie eggs. During incubation, there was an increase in the total bacterial load, but a decrease in C. albicans on urban eggs relative to rural eggs. Rural eggs showed a greater increase in E. coli/Shigella spp. relative to their urban counterpart. Hatching success of the brood was generally lower in urban than rural population. Nestling survival was differentially related with the eggshell microbial abundance between urban and rural populations, which was speculated to be the result of the difference in the strength of the interaction among the microbes. This is the first demonstration that avian clutches in urban and rural populations differ in eggshell microbial abundance, which can be further related to the difference in hatching success and nestling survival in these two types of environments. We suggest that future studies on the eggshell microbes should investigate the interaction among the microbes, because the incubation and/or environmental factors such as urbanization or climate condition can influence the dynamic interactions among the microbes on the eggshells which can further determine the

  18. Water relations and photosynthesis in the cryptoendolithic microbial habitat of hot and cold deserts

    Science.gov (United States)

    Palmer, R. J. Jr; Friedmann, E. I.

    1990-01-01

    Two cryptoendolithic microbial communities, lichens in the Ross Desert of Antarctica and cyanobacteria in the Negev Desert, inhabit porous sandstone rocks of similar physical structure. Both rock types adsorb water vapor by physical mechanisms unrelated to biological processes. Yet the two microbial communities respond differently to water stress: cryptoendolithic lichens begin to photosynthesize at a matric water potential of -46.4 megaPascals (MPa) [70% relative humidity (RH) at 8 degrees C], resembling thallose desert lichens. Cryptoendolithic cyanobacteria, like other prokaryotes, photosynthesize only at very high matric water potentials [> -6.9 MPa, 90% RH at 20 degrees C].

  19. Habitat heterogeneity and connectivity shape microbial communities in South American peatlands.

    Science.gov (United States)

    Oloo, Felix; Valverde, Angel; Quiroga, María Victoria; Vikram, Surendra; Cowan, Don; Mataloni, Gabriela

    2016-05-10

    Bacteria play critical roles in peatland ecosystems. However, very little is known of how habitat heterogeneity affects the structure of the bacterial communities in these ecosystems. Here, we used amplicon sequencing of the 16S rRNA and nifH genes to investigate phylogenetic diversity and bacterial community composition in three different sub-Antarctic peat bog aquatic habitats: Sphagnum magellanicum interstitial water, and water from vegetated and non-vegetated pools. Total and putative nitrogen-fixing bacterial communities from Sphagnum interstitial water differed significantly from vegetated and non-vegetated pool communities (which were colonized by the same bacterial populations), probably as a result of differences in water chemistry and biotic interactions. Total bacterial communities from pools contained typically aquatic taxa, and were more dissimilar in composition and less species rich than those from Sphagnum interstitial waters (which were enriched in taxa typically from soils), probably reflecting the reduced connectivity between the former habitats. These results show that bacterial communities in peatland water habitats are highly diverse and structured by multiple concurrent factors.

  20. Habitat heterogeneity and connectivity shape microbial communities in South American peatlands

    Science.gov (United States)

    Oloo, Felix; Valverde, Angel; Quiroga, María Victoria; Vikram, Surendra; Cowan, Don; Mataloni, Gabriela

    2016-01-01

    Bacteria play critical roles in peatland ecosystems. However, very little is known of how habitat heterogeneity affects the structure of the bacterial communities in these ecosystems. Here, we used amplicon sequencing of the 16S rRNA and nifH genes to investigate phylogenetic diversity and bacterial community composition in three different sub-Antarctic peat bog aquatic habitats: Sphagnum magellanicum interstitial water, and water from vegetated and non-vegetated pools. Total and putative nitrogen-fixing bacterial communities from Sphagnum interstitial water differed significantly from vegetated and non-vegetated pool communities (which were colonized by the same bacterial populations), probably as a result of differences in water chemistry and biotic interactions. Total bacterial communities from pools contained typically aquatic taxa, and were more dissimilar in composition and less species rich than those from Sphagnum interstitial waters (which were enriched in taxa typically from soils), probably reflecting the reduced connectivity between the former habitats. These results show that bacterial communities in peatland water habitats are highly diverse and structured by multiple concurrent factors. PMID:27162086

  1. Transient exposure to oxygen or nitrate reveals ecophysiology of fermentative and sulfate-reducing benthic microbial populations.

    Science.gov (United States)

    Saad, Sainab; Bhatnagar, Srijak; Tegetmeyer, Halina E; Geelhoed, Jeanine S; Strous, Marc; Ruff, S Emil

    2017-12-01

    For the anaerobic remineralization of organic matter in marine sediments, sulfate reduction coupled to fermentation plays a key role. Here, we enriched sulfate-reducing/fermentative communities from intertidal sediments under defined conditions in continuous culture. We transiently exposed the cultures to oxygen or nitrate twice daily and investigated the community response. Chemical measurements, provisional genomes and transcriptomic profiles revealed trophic networks of microbial populations. Sulfate reducers coexisted with facultative nitrate reducers or aerobes enabling the community to adjust to nitrate or oxygen pulses. Exposure to oxygen and nitrate impacted the community structure, but did not suppress fermentation or sulfate reduction as community functions, highlighting their stability under dynamic conditions. The most abundant sulfate reducer in all cultures, related to Desulfotignum balticum, appeared to have coupled both acetate- and hydrogen oxidation to sulfate reduction. We describe a novel representative of the widespread uncultured candidate phylum Fermentibacteria (formerly candidate division Hyd24-12). For this strictly anaerobic, obligate fermentative bacterium, we propose the name ' U Sabulitectum silens' and identify it as a partner of sulfate reducers in marine sediments. Overall, we provide insights into the function of fermentative, as well as sulfate-reducing microbial communities and their adaptation to a dynamic environment. © 2017 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

  2. Transient exposure to oxygen or nitrate reveals ecophysiology of fermentative and sulfate‐reducing benthic microbial populations

    Science.gov (United States)

    Saad, Sainab; Bhatnagar, Srijak; Tegetmeyer, Halina E.; Geelhoed, Jeanine S.; Strous, Marc

    2017-01-01

    Summary For the anaerobic remineralization of organic matter in marine sediments, sulfate reduction coupled to fermentation plays a key role. Here, we enriched sulfate‐reducing/fermentative communities from intertidal sediments under defined conditions in continuous culture. We transiently exposed the cultures to oxygen or nitrate twice daily and investigated the community response. Chemical measurements, provisional genomes and transcriptomic profiles revealed trophic networks of microbial populations. Sulfate reducers coexisted with facultative nitrate reducers or aerobes enabling the community to adjust to nitrate or oxygen pulses. Exposure to oxygen and nitrate impacted the community structure, but did not suppress fermentation or sulfate reduction as community functions, highlighting their stability under dynamic conditions. The most abundant sulfate reducer in all cultures, related to Desulfotignum balticum, appeared to have coupled both acetate‐ and hydrogen oxidation to sulfate reduction. We describe a novel representative of the widespread uncultured candidate phylum Fermentibacteria (formerly candidate division Hyd24‐12). For this strictly anaerobic, obligate fermentative bacterium, we propose the name ‘USabulitectum silens’ and identify it as a partner of sulfate reducers in marine sediments. Overall, we provide insights into the function of fermentative, as well as sulfate‐reducing microbial communities and their adaptation to a dynamic environment. PMID:28836729

  3. Microbial ecology of extreme environments: Antarctic dry valley yeasts and growth in substrate limited habitats

    Science.gov (United States)

    Vishniac, H. S.

    1981-01-01

    The multiple stresses temperature, moisture, and for chemoheterotrophs, sources of carbon and energy of the Dry Valley Antarctica soils allow at best depauperate communities, low in species diversity and population density. The nature of community structure, the operation of biogeochemical cycles, the evolution and mechanisms of adaptation to this habitat are of interest in informing speculations upon life on other planets as well as in modeling the limits of gene life. Yeasts of the Cryptococcus vishniacil complex (Basidiobiastomycetes) are investigated, as the only known indigenes of the most hostile, lichen free, parts of the Dry Valleys. Methods were developed for isolating these yeasts (methods which do not exclude the recovery of other microbiota). The definition of the complex was refined and the importance of nitrogen sources was established as well as substrate competition in fitness to the Dry Valley habitats.

  4. Microbial ecology of extreme environments: Antarctic yeasts and growth in substrate-limited habitats

    Science.gov (United States)

    Vishniac, H. S.

    1984-01-01

    An extreme environment is by definition one with a depauperate biota. While the Ross Desert is by no means homogeneous, the most exposed and arid habitats, soils in the unglaciated high valleys, do indeed contain a very sparse biota of low diversity. So sparse that the natives could easily be outnumbered by airborne exogenous microbes. Native biota must be capable of overwintering as well as growing in the high valley summer. Tourists may undergo a few divisions before contributing their enzymes and, ultimately, elements to the soil - or may die before landing. The simplest way to demonstrate the indigenicity of a particular microbe is therefore to establish unique distribution; occurrence only in the habitat in question precludes foreign origin.

  5. Extracellular polymeric substances are transient media for microbial extracellular electron transfer

    DEFF Research Database (Denmark)

    Xiao, Yong; Zhang, Enhua; Zhang, Jingdong

    2017-01-01

    in microbiology and microbial exploitation for mineral bio-respiration, pollutant conversion, and bioenergy production. We have addressed these challenges by comparing pure and EPS-depleted samples of three representative electrochemically active strains viz Gram-negative Shewanella oneidensis MR-1, Gram......-positive Bacillus sp. WS-XY1, and yeast Pichia stipites using technology from electrochemistry, spectroscopy, atomic force microscopy, and microbiology. Voltammetry discloses redox signals from cytochromes and flavins in intact MR-1 cells, whereas stronger signals from cytochromes and additional signals from both...

  6. Response of core microbial consortia to hydrocarbon contaminations in coastal sediment habitats

    Directory of Open Access Journals (Sweden)

    Mathilde Jeanbille

    2016-10-01

    Full Text Available Traditionally, microbial surveys investigating the effect of chronic anthropogenic pressure such as polyaromatic hydrocarbons (PAHs contaminations consider just the alpha and beta diversity and ignore the interactions among the different taxa forming the microbial community. Here, we investigated the ecological relationships between the three domains of life (i.e. Bacteria, Archaea and Eukarya using 454 pyrosequencing data of the 16S rRNA and 18S rRNA genes from chronically impacted and pristine sediments, along the coasts of the Mediterranean Sea (Gulf of Lion, Vermillion coast, Corsica, Bizerte lagoon and Lebanon and the French Atlantic Ocean (Bay of Biscay and English Channel. Our approach provided a robust ecological framework for the partition of the taxa abundance distribution into 859 core OTUs and 6629 satellite OTUs. OTUs forming the core microbial community showed the highest sensitivity to changes in environmental and contaminant variations, with salinity, latitude, temperature, particle size distribution, total organic carbon (TOC and PAH concentrations as main drivers of community assembly. The core communities were dominated by Gammaproteobacteria and Deltaproteobacteria for Bacteria, by Thaumarchaeota, Bathyarchaeota and Thermoplasmata for Archaea and Metazoa and Dinoflagellata for Eukarya. In order to find associations among microorganisms, we generated a co-occurrence network in which PAHs were found to impact significantly the potential predator – prey relationship in one microbial consortium composed of ciliates and Actinobacteria. Comparison of network topological properties between contaminated and non-contaminated samples showed substantial differences in the structure of the network and indicated a higher vulnerability to environmental perturbations in the contaminated sediments.

  7. Microbial ecology of extreme environments: Antarctic dry valley yeasts and growth in substrate-limited habitats

    Science.gov (United States)

    Vishniac, H. S.

    1982-01-01

    The success of the Antarctic Dry Valley yeasts presumeably results from adaptations to multiple stresses, to low temperatures and substrate-limitation as well as prolonged resting periods enforced by low water availability. Previous investigations have suggested that the crucial stress is substrate limitation. Specific adaptations may be pinpointed by comparing the physiology of the Cryptococcus vishniacii complex, the yeasts of the Tyrol Valley, with their congeners from other habitats. Progress was made in methods of isolation and definition of ecological niches, in the design of experiments in competition for limited substrate, and in establishing the relationships of the Cryptococcus vishniacii complex with other yeasts. In the course of investigating relationships, a new method for 25SrRNA homology was developed. For the first time it appears that 25SrRNA homology may reflect parallel or convergent evolution.

  8. Patterns and variability in geochemical signatures and microbial activity within and between diverse cold seep habitats along the lower continental slope, Northern Gulf of Mexico

    Science.gov (United States)

    Bowles, Marshall; Hunter, Kimberley S.; Samarkin, Vladimir; Joye, Samantha

    2016-07-01

    We collected 69 sediment cores from distinct ecological and geological settings along the deep slope in the Northern Gulf of Mexico to evaluate whether specific geochemical- or habitat-related factors correlated with rates of microbial processes and geochemical signatures. By collecting replicate cores from distinct habitats across multiple sites, we illustrate and quantify the heterogeneity of cold seep geochemistry and microbial activity. These data also document the factors driving unique aspects of the geochemistry of deep slope gas, oil and brine seeps. Surprisingly little variation was observed between replicate (n=2-5) cores within sites for most analytes (except methane), implying that the common practice of collecting one core for geochemical analysis can capture the signature of a habitat in most cases. Depth-integrated concentrations of methane, dissolved inorganic carbon (DIC), and calcium were the predominant geochemical factors that correlated with a site's ecological or geological settings. Pore fluid methane concentration was related to the phosphate and DIC concentration, as well as to rates of sulfate reduction. While distinctions between seep habitats were identified from geochemical signatures, habitat specific geochemistry varied little across sites. The relative concentration of dissolved inorganic nitrogen versus phosphorus suggests that phosphorus availability limits biomass production at cold seeps. Correlations between calcium, chloride, and phosphate concentrations were indicative of brine-associated phosphate transport, suggesting that in addition to the co-migration of methane, dissolved organic carbon, and ammonium with brine, phosphate delivery is also associated with brine advection.

  9. Determination of charge transfer resistance and capacitance of microbial fuel cell through a transient response analysis of cell voltage.

    Science.gov (United States)

    Ha, Phuc Thi; Moon, Hyunsoo; Kim, Byung Hong; Ng, How Yong; Chang, In Seop

    2010-03-15

    An alternative method for determining the charge transfer resistance and double-layer capacitance of microbial fuel cells (MFCs), easily implemented without a potentiostat, was developed. A dynamic model with two parameters, the charge transfer resistance and double-layer capacitance of electrodes, was derived from a linear differential equation to depict the current generation with respect to activation overvoltage. This model was then used to fit the transient cell voltage response to the current step change during the continuous operation of a flat-plate type MFC fed with acetate. Variations of the charge transfer resistance and the capacitance value with respect to the MFC design conditions (biocatalyst existence and electrode area) and operating parameters (acetate concentration and buffer strength in the catholyte) were then determined to elucidate the validity of the proposed method. This model was able to describe the dynamic behavior of the MFC during current change in the activation loss region; having an R(2) value of over 0.99 in most tests. Variations of the charge transfer resistance value (thousands of Omega) according to the change of the design factors and operational factors were well-correlated with the corresponding MFC performances. However, though the capacitance values (approximately 0.02 F) reflected the expected trend according to the electrode area change and catalyst property, they did not show significant variation with changes in either the acetate concentration or buffer strength. (c) 2009 Elsevier B.V. All rights reserved.

  10. Seasonal and environmental influences on recruitment patterns and habitat usage among resident and transient fishes in a World Heritage Site subtropical estuary.

    Science.gov (United States)

    Pichler, H A; Gray, C A; Broadhurst, M K; Spach, H L; Nagelkerken, I

    2017-01-01

    This study investigated whether the fish communities inhabiting shallow non-vegetated habitats in two divergent bays in a subtropical World Heritage Site estuarine system differed according to wet (spring-summer) and dry (autumn-winter) seasons or polyhaline and mesohaline zones, within the broader objective of facilitating spatio-temporal management. Species richness (total of 74 taxa; total length, L T  = 11-552 mm) and abundance (51 109 individuals) were mostly greater in the wet than dry season and in polyhaline than mesohaline areas. There was a major effect of rainfall on recruitment, particularly among transient fishes, which could be the result of enhanced survival of young via greater productivity (food resources) and protection from predators (via turbidity reducing visual cues). Salinity had strong interactive effects with rainfall and temperature in one bay, with greater species richness and overall abundances as well as large abundances of four key species [Anchoa januaria and Atherinella brasiliensis (pelagic residents), Cetengraulis edentulus (pelagic transient) and Diapterus rhombeus (demersal transient)] during the wet season in polyhaline areas; possibly reflecting a biodiversity hotspot that might be affected by distance to the estuary mouth and convergence hydrology. Regionally, the results support enforcing spatio-temporal restrictions to minimize anthropogenic activities within statutory (but not always enforced) protected areas. Globally, the data reiterate the need to identify and understand biotic and abiotic effects on estuarine ichthyofaunal distributions and abundances as a precursor to their management. © 2016 The Fisheries Society of the British Isles.

  11. Evidence of the St. Clair-Detroit River system as a dispersal corridor and nursery habitat for transient larval burbot

    Science.gov (United States)

    McCullough, Darrin E.; Roseman, Edward F.; Keeler, Kevin M.; DeBruyne, Robin L.; Pritt, Jeremy J.; Thompson, Patricia A.; Ireland, Stacey A.; Ross, Jason E.; Bowser, Dustin; Hunter, Robert D.; Castle, Dana Kristina; Fischer, Jason; Provo, Stacy A.

    2015-01-01

    Burbot Lota lota are distributed across the Laurentian Great Lakes where they occupy a top piscivore role. The St. Clair-Detroit River System is known to provide a migration corridor as well as spawning and nursery habitat for many indigenous fishes of economic and ecological significance. However, knowledge is scant of the early life history of burbot and the importance of this system in their dispersal, survival, and recruitment. In order to assess the role of the St. Clair-Detroit River System to burbot ecology, we collected larval burbot during ichthyoplankton surveys in this system from 2010 to 2013 as part of a habitat restoration monitoring program. More and larger burbot larvae were found in the St. Clair River than in the lower Detroit River, although this may be due to differences in sampling methods between the two rivers. Consistent with existing studies, larval burbot exhibited ontogenesis with a distinct transition from a pelagic zooplankton-based diet to a benthic macroinvertebrate-based diet. Our results demonstrate that the St. Clair-Detroit Rivers provide food resources, required habitat, and a migration conduit between the upper and lower Great Lakes, but the contribution of these fish to the lower lakes requires further examination.

  12. The effect of soil habitat connectivity on microbial interactions, community structure and diversity: a microcosm-based approach

    NARCIS (Netherlands)

    Wolf, A.B.

    2014-01-01

    Soils contain tremendous microbial phylogenetic and functional diversity. Recent advances in the application of molecular methods into microbial ecology have provided a new appreciation of the extent of soil-borne microbial diversity, but our understanding of the forces that shape and maintain this

  13. Transient exposure to oxygen or nitrate reveals ecophysiology of fermentative and sulfate-reducing benthic microbial populations

    NARCIS (Netherlands)

    Saad, S.; Bhatnagar, S.; Tegetmeyer, H.E.; Geelhoed, J.S.; Strous, M.; Ruff, S.E.

    2017-01-01

    SummaryFor the anaerobic remineralization of organic matter inmarine sediments, sulfate reduction coupled to fer-mentation plays a key role. Here, we enriched sulfate-reducing/fermentative communities from intertidalsediments under defined conditions in continuousculture. We transiently exposed

  14. In situ dynamics of O2, pH, light and photosynthesis in ikaite tufa columns (Ikka Fjord, Greenland – a unique microbial habitat.

    Directory of Open Access Journals (Sweden)

    Erik Christian Løvbjerg Trampe

    2016-05-01

    Full Text Available The Ikka Fjord (SW Greenland harbors a unique microbial habitat in the form of several hundred submarine tufa columns composed of ikaite, a special hexahydrate form of calcium carbonate that precipitates when alkaline phosphate- and carbonate-enriched spring water seeping out of the sea floor meets cold seawater. While several unique heterotrophic microbes have been isolated from the tufa columns, the microbial activity and the boundary conditions for microbial growth in ikaite have remained unexplored. We present the first detailed in situ characterization of the physico-chemical microenvironment and activity of oxygenic phototrophs thriving within the ikaite columns. In situ underwater microsensor measurements of pH, temperature, and irradiance in the porous ikaite crystal matrix, revealed an extreme microenvironment characterized by low temperatures, strong light attenuation, and gradients of pH changing from pH 9 at the outer column surface to above pH 10 over the first 1-2 cm of the ikaite. This outer layer of the freshly deposited ikaite matrix contained densely pigmented yellow and green zones harboring a diverse phototrophic community dominated by diatoms and cyanobacteria, respectively, as shown by amplicon sequencing. In situ O2 measurements, as well as underwater variable chlorophyll fluorescence measurements of photosynthetic activity, demonstrated high levels of oxygenic photosynthesis in this extreme gradient environment with strong irradiance-driven O2 dynamics ranging from anoxia to hyperoxic conditions in the ikaite matrix, albeit the local formation of gas bubbles buffered the day-night dynamics of O2 in the tufa columns. The microbial phototrophs in the ikaite matrix are embedded in exopolymers forming endolithic biofilms that may interact with mineral formation and cementing of ikaite crystals.

  15. In situ Dynamics of O2, pH, Light, and Photosynthesis in Ikaite Tufa Columns (Ikka Fjord, Greenland)-A Unique Microbial Habitat.

    Science.gov (United States)

    Trampe, Erik C L; Larsen, Jens E N; Glaring, Mikkel A; Stougaard, Peter; Kühl, Michael

    2016-01-01

    The Ikka Fjord (SW Greenland) harbors a unique microbial habitat in the form of several hundred submarine tufa columns composed of ikaite, a special hexahydrate form of calcium carbonate that precipitates when alkaline phosphate- and carbonate-enriched spring water seeping out of the sea floor meets cold seawater. While several unique heterotrophic microbes have been isolated from the tufa columns, the microbial activity, and the boundary conditions for microbial growth in ikaite have remained unexplored. We present the first detailed in situ characterization of the physico-chemical microenvironment and activity of oxygenic phototrophs thriving within the ikaite columns. In situ underwater microsensor measurements of pH, temperature, and irradiance in the porous ikaite crystal matrix, revealed an extreme microenvironment characterized by low temperatures, strong light attenuation, and gradients of pH changing from pH 9 at the outer column surface to above pH 10 over the first 1-2 cm of the ikaite. This outer layer of the freshly deposited ikaite matrix contained densely pigmented yellow and green zones harboring a diverse phototrophic community dominated by diatoms and cyanobacteria, respectively, as shown by amplicon sequencing. In situ O2 measurements, as well as underwater variable chlorophyll fluorescence measurements of photosynthetic activity, demonstrated high levels of oxygenic photosynthesis in this extreme gradient environment with strong irradiance-driven O2 dynamics ranging from anoxia to hyperoxic conditions in the ikaite matrix, albeit the local formation of gas bubbles buffered the day-night dynamics of O2 in the tufa columns. The microbial phototrophs in the ikaite matrix are embedded in exopolymers forming endolithic biofilms that may interact with mineral formation and cementing of ikaite crystals.

  16. In situ Dynamics of O2, pH, Light, and Photosynthesis in Ikaite Tufa Columns (Ikka Fjord, Greenland)—A Unique Microbial Habitat

    Science.gov (United States)

    Trampe, Erik C. L.; Larsen, Jens E. N.; Glaring, Mikkel A.; Stougaard, Peter; Kühl, Michael

    2016-01-01

    The Ikka Fjord (SW Greenland) harbors a unique microbial habitat in the form of several hundred submarine tufa columns composed of ikaite, a special hexahydrate form of calcium carbonate that precipitates when alkaline phosphate- and carbonate-enriched spring water seeping out of the sea floor meets cold seawater. While several unique heterotrophic microbes have been isolated from the tufa columns, the microbial activity, and the boundary conditions for microbial growth in ikaite have remained unexplored. We present the first detailed in situ characterization of the physico-chemical microenvironment and activity of oxygenic phototrophs thriving within the ikaite columns. In situ underwater microsensor measurements of pH, temperature, and irradiance in the porous ikaite crystal matrix, revealed an extreme microenvironment characterized by low temperatures, strong light attenuation, and gradients of pH changing from pH 9 at the outer column surface to above pH 10 over the first 1–2 cm of the ikaite. This outer layer of the freshly deposited ikaite matrix contained densely pigmented yellow and green zones harboring a diverse phototrophic community dominated by diatoms and cyanobacteria, respectively, as shown by amplicon sequencing. In situ O2 measurements, as well as underwater variable chlorophyll fluorescence measurements of photosynthetic activity, demonstrated high levels of oxygenic photosynthesis in this extreme gradient environment with strong irradiance-driven O2 dynamics ranging from anoxia to hyperoxic conditions in the ikaite matrix, albeit the local formation of gas bubbles buffered the day-night dynamics of O2 in the tufa columns. The microbial phototrophs in the ikaite matrix are embedded in exopolymers forming endolithic biofilms that may interact with mineral formation and cementing of ikaite crystals. PMID:27242741

  17. A Synthetic Ecology Perspective: How Well Does Behavior of Model Organisms in the Laboratory Predict Microbial Activities in Natural Habitats?

    Science.gov (United States)

    Yu, Zheng; Krause, Sascha M B; Beck, David A C; Chistoserdova, Ludmila

    2016-01-01

    In this perspective article, we question how well model organisms, the ones that are easy to cultivate in the laboratory and that show robust growth and biomass accumulation, reflect the dynamics and interactions of microbial communities observed in nature. Today's -omics toolbox allows assessing the genomic potential of microbes in natural environments in a high-throughput fashion and at a strain-level resolution. However, understanding of the details of microbial activities and of the mechanistic bases of community function still requires experimental validation in simplified and fully controlled systems such as synthetic communities. We have studied methane utilization in Lake Washington sediment for a few decades and have identified a number of species genetically equipped for this activity. We have also identified co-occurring satellite species that appear to form functional communities together with the methanotrophs. Here, we compare experimental findings from manipulation of natural communities involved in metabolism of methane in this niche with findings from manipulation of synthetic communities assembled in the laboratory of species originating from the same study site, from very simple (two-species) to rather complex (50-species) synthetic communities. We observe some common trends in community dynamics between the two types of communities, toward representation of specific functional guilds. However, we also identify strong discrepancies between the dominant methane oxidizers in synthetic communities compared to natural communities, under similar incubation conditions. These findings highlight the challenges that exist in using the synthetic community approach to modeling dynamics and species interactions in natural communities.

  18. Spatial and Temporal Changes in Fluid Chemistry and Microbial Community Diversity in Subseafloor Habitats at Axial Seamount Following the 1998 Eruption

    Science.gov (United States)

    Opatkiewicz, A. D.; Butterfield, D. A.; Baross, J. A.

    2006-12-01

    The subseafloor associated with hydrothermal vents has the potential to contribute significantly to primary production and biogeochemical cycling in the ocean. However, too little is known about the phylogenetic and physiological diversity of the microbial communities or their in situ activity to assess this potential. There are previous reports that subseafloor environments at active vent sites harbor a high diversity of microorganisms that include different thermal and metabolic groups of Bacteria and Archaea. However, little is known about how these communities change over time (minutes to years), at different vent sites, or in response to perturbations. In an effort to address these issues, the subseafloor microbial community diversity was examined from five diffuse-flow hydrothermal vent sites (distributed geographically over the seamount between three distinguishable vent fields) over the course of six years following the 1998 eruption at Axial Seamount (45° 58'N; 130° 00' W). PCR-based Terminal Restriction Fragment Length Polymorphism (TRFLP) analyses were used to follow changes in the microbial community structure. 16S rRNA gene sequence analysis was used to identify the specific groups of Bacteria and Archaea from the TRFLP analyses. Deep-sea background seawater microorganisms were detected in hydrothermal fluid samples (Bacteria: Alpha and Gamma Proteobacteria, Archaea: Marine Group I Crenarchaeota and Marine Group II Euryarchaeota). The unique subseafloor phylotypes detected included Epsilon, Delta and Beta Proteobacteria, Methanococcales and thermophilic Euryarchaeota. Temperature and key chemical species, which indicate the degree of mixing of hydrothermal fluid with seawater in the subsurface, have been shown previously to be important in affecting the diversity of the microbial communities (Huber et al., 2003). This work substantiates these earlier findings and furthermore presents evidence that additional chemical species, distinguishing the

  19. Discovery and Description of Giant Submarine Smectite Cones on the Seafloor in Eyjafjordur, Northern Iceland, and a Novel Thermal Microbial Habitat

    Science.gov (United States)

    Marteinsson, Viggó Thór; Kristjánsson, Jakob K.; Kristmannsdóttir, Hrefna; Dahlkvist, Maria; Sæmundsson, Kristján; Hannington, Mark; Pétursdóttir, Sólveig K.; Geptner, Alfred; Stoffers, Peter

    2001-01-01

    With the submersible JAGO and by scuba diving we discovered three remarkable geothermal cones, rising 33, 25, and 45 m from the seafloor at a depth of 65 m in Eyjafjordur, northern Iceland. The greatest geothermal activity was on the highest cone, which discharged up to 50 liters of freshwater per s at 72°C and pH 10.0. The cones were built up from precipitated smectite, formed by mixing of the hot SiO2-rich geothermal fluid with the cold Mg-rich seawater. By connecting a rubber hose to one outflow, about 240 liters of pure geothermal fluids was concentrated through a 0.2-μm-pore-size filter. Among 50 thermophilic isolates, we found members of Bacillus and Thermonema and a new unidentified low-G+C gram-positive member of the Bacteria as well as one member of the Archaea, Desulfurococcus mobilis. Analysis of small-subunit rRNA genes PCR amplified and cloned directly from environmental DNA showed that 41 out of 45 Bacteria sequences belonged to members of the Aquificales, whereas all of the 10 Archaea sequences belonged to the Korarchaeota. The physiological characteristics of isolates from different parts of the cones indicate a completely freshwater habitat, supporting the possibility of subterranean transmittance of terrestrial organisms. PMID:11157250

  20. Transient analyzer

    International Nuclear Information System (INIS)

    Muir, M.D.

    1975-01-01

    The design and design philosophy of a high performance, extremely versatile transient analyzer is described. This sub-system was designed to be controlled through the data acquisition computer system which allows hands off operation. Thus it may be placed on the experiment side of the high voltage safety break between the experimental device and the control room. This analyzer provides control features which are extremely useful for data acquisition from PPPL diagnostics. These include dynamic sample rate changing, which may be intermixed with multiple post trigger operations with variable length blocks using normal, peak to peak or integrate modes. Included in the discussion are general remarks on the advantages of adding intelligence to transient analyzers, a detailed description of the characteristics of the PPPL transient analyzer, a description of the hardware, firmware, control language and operation of the PPPL transient analyzer, and general remarks on future trends in this type of instrumentation both at PPPL and in general

  1. Deep subsurface microbial processes

    Science.gov (United States)

    Lovley, D.R.; Chapelle, F.H.

    1995-01-01

    Information on the microbiology of the deep subsurface is necessary in order to understand the factors controlling the rate and extent of the microbially catalyzed redox reactions that influence the geophysical properties of these environments. Furthermore, there is an increasing threat that deep aquifers, an important drinking water resource, may be contaminated by man's activities, and there is a need to predict the extent to which microbial activity may remediate such contamination. Metabolically active microorganisms can be recovered from a diversity of deep subsurface environments. The available evidence suggests that these microorganisms are responsible for catalyzing the oxidation of organic matter coupled to a variety of electron acceptors just as microorganisms do in surface sediments, but at much slower rates. The technical difficulties in aseptically sampling deep subsurface sediments and the fact that microbial processes in laboratory incubations of deep subsurface material often do not mimic in situ processes frequently necessitate that microbial activity in the deep subsurface be inferred through nonmicrobiological analyses of ground water. These approaches include measurements of dissolved H2, which can predict the predominant microbially catalyzed redox reactions in aquifers, as well as geochemical and groundwater flow modeling, which can be used to estimate the rates of microbial processes. Microorganisms recovered from the deep subsurface have the potential to affect the fate of toxic organics and inorganic contaminants in groundwater. Microbial activity also greatly influences 1 the chemistry of many pristine groundwaters and contributes to such phenomena as porosity development in carbonate aquifers, accumulation of undesirably high concentrations of dissolved iron, and production of methane and hydrogen sulfide. Although the last decade has seen a dramatic increase in interest in deep subsurface microbiology, in comparison with the study of

  2. Transient pseudohypoaldosteronism

    Directory of Open Access Journals (Sweden)

    Stajić Nataša

    2011-01-01

    Full Text Available Introduction. Infants with urinary tract malformations (UTM presenting with urinary tract infection (UTI are prone to develop transient type 1 pseudohypoaldosteronism (THPA1. Objective. Report on patient series with characteristics of THPA1, UTM and/or UTI and suggestions for the diagnosis and therapy. Methods. Patients underwent blood and urine electrolyte and acid-base analysis, serum aldosterosterone levels and plasma rennin activity measuring; urinalysis, urinoculture and renal ultrasound were done and medical and/or surgical therapy was instituted. Results. Hyponatraemia (120.9±5.8 mmol/L, hyperkalaemia (6.9±0.9 mmol/L, metabolic acidosis (plasma bicarbonate, 11±1.4 mmol/L, and a rise in serum creatinine levels (145±101 μmol/L were associated with inappropriately high urinary sodium (51.3±17.5 mmol/L and low potassium (14.1±5.9 mmol/L excretion. Elevated plasma aldosterone concentrations (170.4±100.5 ng/dL and the very high levels of the plasma aldosterone to potassium ratio (25.2±15.6 together with diminished urinary K/Na values (0.31±0.19 indicated tubular resistance to aldosterone. After institution of appropriate medical and/or surgical therapy, serum electrolytes, creatinine, and acid-base balance were normalized. Imaging studies showed ureteropyelic or ureterovesical junction obstruction in 3 and 2 patients, respectively, posterior urethral valves in 3, and normal UT in 1 patient. According to our knowledge, this is the first report on THPA1 in the Serbian literature. Conclusion. Male infants with hyponatraemia, hyperkalaemia and metabolic acidosis have to have their urine examined and the renal ultrasound has to be done in order to avoid both, the underdiagnosis of THPA1 and the inappropriate medication.

  3. The Habitat Connection.

    Science.gov (United States)

    Naturescope, 1987

    1987-01-01

    Consists of activities which address the causes of habitat destruction and the effects of habitat loss on animals and plants. Identifies habitat loss as the major reason for the endangerment and extinction of plant and animal species. (ML)

  4. Microbial ecology of terrestrial Antarctica: Are microbial systems at risk from human activities?

    Energy Technology Data Exchange (ETDEWEB)

    White, G.J.

    1996-08-01

    Many of the ecological systems found in continental Antarctica are comprised entirely of microbial species. Concerns have arisen that these microbial systems might be at risk either directly through the actions of humans or indirectly through increased competition from introduced species. Although protection of native biota is covered by the Protocol on Environmental Protection to the Antarctic Treaty, strict measures for preventing the introduction on non-native species or for protecting microbial habitats may be impractical. This report summarizes the research conducted to date on microbial ecosystems in continental Antarctica and discusses the need for protecting these ecosystems. The focus is on communities inhabiting soil and rock surfaces in non-coastal areas of continental Antarctica. Although current polices regarding waste management and other operations in Antarctic research stations serve to reduce the introduction on non- native microbial species, importation cannot be eliminated entirely. Increased awareness of microbial habitats by field personnel and protection of certain unique habitats from physical destruction by humans may be necessary. At present, small-scale impacts from human activities are occurring in certain areas both in terms of introduced species and destruction of habitat. On a large scale, however, it is questionable whether the introduction of non-native microbial species to terrestrial Antarctica merits concern.

  5. Current interruption transients calculation

    CERN Document Server

    Peelo, David F

    2014-01-01

    Provides an original, detailed and practical description of current interruption transients, origins, and the circuits involved, and how they can be calculated Current Interruption Transients Calculationis a comprehensive resource for the understanding, calculation and analysis of the transient recovery voltages (TRVs) and related re-ignition or re-striking transients associated with fault current interruption and the switching of inductive and capacitive load currents in circuits. This book provides an original, detailed and practical description of current interruption transients, origins,

  6. Transient drainage summary report

    International Nuclear Information System (INIS)

    1996-09-01

    This report summarizes the history of transient drainage issues on the Uranium Mill Tailings Remedial Action (UMTRA) Project. It defines and describes the UMTRA Project disposal cell transient drainage process and chronicles UMTRA Project treatment of the transient drainage phenomenon. Section 4.0 includes a conceptual cross section of each UMTRA Project disposal site and summarizes design and construction information, the ground water protection strategy, and the potential for transient drainage

  7. PSH Transient Simulation Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Muljadi, Eduard [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-12-21

    PSH Transient Simulation Modeling presentation from the WPTO FY14 - FY16 Peer Review. Transient effects are an important consideration when designing a PSH system, yet numerical techniques for hydraulic transient analysis still need improvements for adjustable-speed (AS) reversible pump-turbine applications.

  8. Coastal Critical Habitat Designations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Endangered Species Act (ESA) requires the Federal government to designate critical habitat, areas of habitat essential to the species' conservation, for ESA...

  9. California Condor Critical Habitat

    Data.gov (United States)

    California Natural Resource Agency — These Data identify (in general) the areas where critical habitat for the California Condor occur. Critical habitat for the species consists of the following 10...

  10. Indicators: Physical Habitat Complexity

    Science.gov (United States)

    Physical habitat complexity measures the amount and variety of all types of cove at the water’s edge in lakes. In general, dense and varied shoreline habitat is able to support more diverse communities of aquatic life.

  11. Microbial Safari.

    Science.gov (United States)

    Wagner, Stephen C.; Stewart, Robert S., Jr.

    2000-01-01

    Introduces an investigative microbiology laboratory activity emphasizing critical thinking and experimental design in which students isolate and characterize a bacterium from a specific habitat. Explains the procedures of the laboratory including safety, sample collection, and isolation. (YDS)

  12. EVALUATION OF MICROBIAL SURVIVAL IN EXTRATERRESTRIAL ENVIRONMENTS

    Directory of Open Access Journals (Sweden)

    Betül BULUÇ

    2012-08-01

    Full Text Available In this paper, the space environments where microbial terrestrial life could form and evolve in, were evaluted with the base of the physical and chemical properties. In addition, Earthial microbial life formation conditions in the interstellar medium and the other planets are investigated and the survival of microorganisms in the space environments are questioned. As a result, considering the aspects of terrestrial microbial life, we suggest that the space environment and other planets could not be a habitat for Earthial microorganisms.

  13. Microbial biosensors

    International Nuclear Information System (INIS)

    Le Yu; Chen, Wilfred; Mulchandani, Ashok

    2006-01-01

    A microbial biosensor is an analytical device that couples microorganisms with a transducer to enable rapid, accurate and sensitive detection of target analytes in fields as diverse as medicine, environmental monitoring, defense, food processing and safety. The earlier microbial biosensors used the respiratory and metabolic functions of the microorganisms to detect a substance that is either a substrate or an inhibitor of these processes. Recently, genetically engineered microorganisms based on fusing of the lux, gfp or lacZ gene reporters to an inducible gene promoter have been widely applied to assay toxicity and bioavailability. This paper reviews the recent trends in the development and application of microbial biosensors. Current advances and prospective future direction in developing microbial biosensor have also been discussed

  14. Influence of ice and snow covers on the UV exposure of terrestrial microbial communities: dosimetric studies.

    Science.gov (United States)

    Cockell, Charles S; Rettberg, Petra; Horneck, Gerda; Wynn-Williams, David D; Scherer, Kerstin; Gugg-Helminger, Anton

    2002-08-01

    Bacillus subtilis spore biological dosimeters and electronic dosimeters were used to investigate the exposure of terrestrial microbial communities in micro-habitats covered by snow and ice in Antarctica. The melting of snow covers of between 5- and 15-cm thickness, depending on age and heterogeneity, could increase B. subtilis spore inactivation by up to an order of magnitude, a relative increase twice that caused by a 50% ozone depletion. Within the snow-pack at depths of less than approximately 3 cm snow algae could receive two to three times the DNA-weighted irradiance they would receive on bare ground. At the edge of the snow-pack, warming of low albedo soils resulted in the formation of overhangs that provided transient UV protection to thawed and growing microbial communities on the soils underneath. In shallow aquatic habitats, thin layers of heterogeneous ice of a few millimetres thickness were found to reduce DNA-weighted irradiances by up to 55% compared to full-sky values with equivalent DNA-weighted diffuse attenuation coefficients (K(DNA)) of >200 m(-1). A 2-mm snow-encrusted ice cover on a pond was equivalent to 10 cm of ice on a perennially ice covered lake. Ice covers also had the effect of stabilizing the UV exposure, which was often subject to rapid variations of up to 33% of the mean value caused by wind-rippling of the water surface. These data show that changing ice and snow covers cause relative changes in microbial UV exposure at least as great as those caused by changing ozone column abundance. Copyright 2002 Elsevier Science B.V.

  15. Riverine habitat dynamics

    Science.gov (United States)

    Jacobson, R.B.

    2013-01-01

    The physical habitat template is a fundamental influence on riverine ecosystem structure and function. Habitat dynamics refers to the variation in habitat through space and time as the result of varying discharge and varying geomorphology. Habitat dynamics can be assessed at spatial scales ranging from the grain (the smallest resolution at which an organism relates to its environment) to the extent (the broadest resolution inclusive of all space occupied during its life cycle). In addition to a potentially broad range of spatial scales, assessments of habitat dynamics may include dynamics of both occupied and nonoccupied habitat patches because of process interactions among patches. Temporal aspects of riverine habitat dynamics can be categorized into hydrodynamics and morphodynamics. Hydrodynamics refers to habitat variation that results from changes in discharge in the absence of significant change of channel morphology and at generally low sediment-transport rates. Hydrodynamic assessments are useful in cases of relatively high flow exceedance (percent of time a flow is equaled or exceeded) or high critical shear stress, conditions that are applicable in many studies of instream flows. Morphodynamics refers to habitat variation resulting from changes to substrate conditions or channel/floodplain morphology. Morphodynamic assessments are necessary when channel and floodplain boundary conditions have been significantly changed, generally by relatively rare flood events or in rivers with low critical shear stress. Morphodynamic habitat variation can be particularly important as disturbance mechanisms that mediate population growth or for providing conditions needed for reproduction, such as channel-migration events that erode cutbanks and provide new pointbar surfaces for germination of riparian trees. Understanding of habitat dynamics is increasing in importance as societal goals shift toward restoration of riverine ecosystems. Effective investment in restoration

  16. TRANSIENT ELECTRONICS CATEGORIZATION

    Science.gov (United States)

    2017-08-24

    AFRL-RY-WP-TR-2017-0169 TRANSIENT ELECTRONICS CATEGORIZATION Dr. Burhan Bayraktaroglu Devices for Sensing Branch Aerospace Components & Subsystems...SUBTITLE TRANSIENT ELECTRONICS CATEGORIZATION 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER N/A 5c. PROGRAM ELEMENT NUMBER N/A 6. AUTHOR(S) Dr. Burhan...88ABW-2017-3747, Clearance Date 31 July 2017. Paper contains color. 14. ABSTRACT Transient electronics is an emerging technology area that lacks proper

  17. Assessing juvenile salmon rearing habitat and associated predation risk in a lower Snake River reservoir

    Science.gov (United States)

    Tiffan, Kenneth F.; Hatten, James R.; Trachtenbarg, David A

    2015-01-01

    Subyearling fall Chinook salmon (Oncorhynchus tshawytscha) in the Columbia River basin exhibit a transient rearing strategy and depend on connected shoreline habitats during freshwater rearing. Impoundment has greatly reduced the amount of shallow-water rearing habitat that is exacerbated by the steep topography of reservoirs. Periodic dredging creates opportunities to strategically place spoils to increase the amount of shallow-water habitat for subyearlings while at the same time reducing the amount of unsuitable area that is often preferred by predators. We assessed the amount and spatial arrangement of subyearling rearing habitat in Lower Granite Reservoir on the Snake River to guide future habitat improvement efforts. A spatially explicit habitat assessment was conducted using physical habitat data, two-dimensional hydrodynamic modelling and a statistical habitat model in a geographic information system framework. We used field collections of subyearlings and a common predator [smallmouth bass (Micropterus dolomieu)] to draw inferences about predation risk within specific habitat types. Most of the high-probability rearing habitat was located in the upper half of the reservoir where gently sloping landforms created low lateral bed slopes and shallow-water habitats. Only 29% of shorelines were predicted to be suitable (probability >0.5) for subyearlings, and the occurrence of these shorelines decreased in a downstream direction. The remaining, less suitable areas were composed of low-probability habitats in unmodified (25%) and riprapped shorelines (46%). As expected, most subyearlings were found in high-probability habitat, while most smallmouth bass were found in low-probability locations. However, some subyearlings were found in low-probability habitats, such as riprap, where predation risk could be high. Given their transient rearing strategy and dependence on shoreline habitats, subyearlings could benefit from habitat creation efforts in the lower

  18. Microbial co-habitation and lateral gene transfer: what transposases can tell us

    Energy Technology Data Exchange (ETDEWEB)

    Hooper, Sean D.; Mavromatis, Konstantinos; Kyrpides, Nikos C.

    2009-03-01

    Determining the habitat range for various microbes is not a simple, straightforward matter, as habitats interlace, microbes move between habitats, and microbial communities change over time. In this study, we explore an approach using the history of lateral gene transfer recorded in microbial genomes to begin to answer two key questions: where have you been and who have you been with? All currently sequenced microbial genomes were surveyed to identify pairs of taxa that share a transposase that is likely to have been acquired through lateral gene transfer. A microbial interaction network including almost 800 organisms was then derived from these connections. Although the majority of the connections are between closely related organisms with the same or overlapping habitat assignments, numerous examples were found of cross-habitat and cross-phylum connections. We present a large-scale study of the distributions of transposases across phylogeny and habitat, and find a significant correlation between habitat and transposase connections. We observed cases where phylogenetic boundaries are traversed, especially when organisms share habitats; this suggests that the potential exists for genetic material to move laterally between diverse groups via bridging connections. The results presented here also suggest that the complex dynamics of microbial ecology may be traceable in the microbial genomes.

  19. Microbial glycoproteomics

    DEFF Research Database (Denmark)

    Halim, Adnan; Anonsen, Jan Haug

    2017-01-01

    Mass spectrometry-based "-omics" technologies are important tools for global and detailed mapping of post-translational modifications. Protein glycosylation is an abundant and important post translational modification widespread throughout all domains of life. Characterization of glycoproteins...... and research in this area is rapidly accelerating. Here, we review recent developments in glycoproteomic technologies with a special focus on microbial protein glycosylation....

  20. Stratification of habitats for identifying habitat selection by Merriam's turkeys

    Science.gov (United States)

    Mark A. Rumble; Stanley H. Anderson

    1992-01-01

    Habitat selection patterns of Merriam’s Turkeys were compared in hierarchical analyses of three levels of habitat stratification. Habitat descriptions in first-level analyses were based on dominant species of vegetation. Habitat descriptions in second-level analyses were based on dominant species of vegetation and overstory canopy cover. Habitat descriptions in third-...

  1. Spectroscopic classification of transients

    DEFF Research Database (Denmark)

    Stritzinger, M. D.; Fraser, M.; Hummelmose, N. N.

    2017-01-01

    We report the spectroscopic classification of several transients based on observations taken with the Nordic Optical Telescope (NOT) equipped with ALFOSC, over the nights 23-25 August 2017.......We report the spectroscopic classification of several transients based on observations taken with the Nordic Optical Telescope (NOT) equipped with ALFOSC, over the nights 23-25 August 2017....

  2. Surface Habitat Systems

    Science.gov (United States)

    Kennedy, Kriss J.

    2009-01-01

    The Surface Habitat Systems (SHS) Focused Investment Group (FIG) is part of the National Aeronautics and Space Administration (NASA) Johnson Space Center (JSC) effort to provide a focused direction and funding to the various projects that are working on human surface habitat designs and technologies for the planetary exploration missions. The overall SHS-FIG effort focuses on directing and guiding those projects that: 1) develop and demonstrate new surface habitat system concepts, innovations, and technologies to support human exploration missions, 2) improve environmental systems that interact with human habitats, 3) handle and emplace human surface habitats, and 4) focus on supporting humans living and working in habitats on planetary surfaces. The activity areas of the SHS FIG described herein are focused on the surface habitat project near-term objectives as described in this document. The SHS-FIG effort focuses on mitigating surface habitat risks (as identified by the Lunar Surface Systems Project Office (LSSPO) Surface Habitat Element Team; and concentrates on developing surface habitat technologies as identified in the FY08 gap analysis. The surface habitat gap assessment will be updated annually as the surface architecture and surface habitat definition continues to mature. These technologies are mapped to the SHS-FIG Strategic Development Roadmap. The Roadmap will bring to light the areas where additional innovative efforts are needed to support the development of habitat concepts and designs and the development of new technologies to support of the LSSPO Habitation Element development plan. Three specific areas of development that address Lunar Architecture Team (LAT)-2 and Constellation Architecture Team (CxAT) Lunar habitat design issues or risks will be focused on by the SHS-FIG. The SHS-FIG will establish four areas of development that will help the projects prepare in their planning for surface habitat systems development. Those development areas are

  3. Wildlife Habitat Evaluation Handbook.

    Science.gov (United States)

    Neilson, Edward L., Jr.; Benson, Delwin E.

    The National 4-H Wildlife Invitational is a competitive event to teach youth about the fundamentals of wildlife management. Youth learn that management for wildlife means management of wildlife habitat and providing for the needs of wildlife. This handbook provides information about wildlife habitat management concepts in both urban and rural…

  4. Wildlife habitat considerations

    Science.gov (United States)

    Helen Y. Smith

    2000-01-01

    Fire, insects, disease, harvesting, and precommercial thinning all create mosaics on Northern Rocky Mountain landscapes. These mosaics are important for faunal habitat. Consequently, changes such as created openings or an increase in heavily stocked areas affect the water, cover, and food of forest habitats. The “no action” alternative in ecosystem management of low...

  5. Critical Habitat :: NOAA Fisheries

    Science.gov (United States)

    occupied by the species at the time of listing, if they contain physical or biological features essential essential for conservation. Critical Habitat Maps NOTE: The critical habitat maps provided here are for Data Leatherback Turtle (U.S. West Coast) » Biological Report » Economic Report 2012 77 FR 4170 Go to

  6. Microfluidics expanding the frontiers of microbial ecology.

    Science.gov (United States)

    Rusconi, Roberto; Garren, Melissa; Stocker, Roman

    2014-01-01

    Microfluidics has significantly contributed to the expansion of the frontiers of microbial ecology over the past decade by allowing researchers to observe the behaviors of microbes in highly controlled microenvironments, across scales from a single cell to mixed communities. Spatially and temporally varying distributions of organisms and chemical cues that mimic natural microbial habitats can now be established by exploiting physics at the micrometer scale and by incorporating structures with specific geometries and materials. In this article, we review applications of microfluidics that have resulted in insightful discoveries on fundamental aspects of microbial life, ranging from growth and sensing to cell-cell interactions and population dynamics. We anticipate that this flexible multidisciplinary technology will continue to facilitate discoveries regarding the ecology of microorganisms and help uncover strategies to control microbial processes such as biofilm formation and antibiotic resistance.

  7. Microbial xanthophylls.

    Science.gov (United States)

    Bhosale, Prakash; Bernstein, Paul S

    2005-09-01

    Xanthophylls are oxygenated carotenoids abundant in the human food supply. Lutein, zeaxanthin, and cryptoxanthin are major xanthophyll carotenoids in human plasma. The consumption of these xanthophylls is directly associated with reduction in the risk of cancers, cardiovascular disease, age-related macular degeneration, and cataract formation. Canthaxanthin and astaxanthin also have considerable importance in aquaculture for salmonid and crustacean pigmentation, and are of commercial interest for the pharmaceutical and food industries. Chemical synthesis is a major source for the heavy demand of xanthophylls in the consumer market; however, microbial producers also have potential as commercial sources. In this review, we discuss the biosynthesis, commercial utility, and major microbial sources of xanthophylls. We also present a critical review of current research and technologies involved in promoting microbes as potential commercial sources for mass production.

  8. Summary of transient analysis

    International Nuclear Information System (INIS)

    Saha, P.

    1984-01-01

    This chapter reviews the papers on the pressurized water reactor (PWR) and boiling water reactor (BWR) transient analyses given at the American Nuclear Society Topical Meeting on Anticipated and Abnormal Plant Transients in Light Water Reactors. Most of the papers were based on the systems calculations performed using the TRAC-PWR, RELAP5 and RETRAN codes. The status of the nuclear industry in the code applications area is discussed. It is concluded that even though comprehensive computer codes are available for plant transient analysis, there is still a need to exercise engineering judgment, simpler tools and even hand calculations to supplement these codes

  9. Habitat Blocks and Wildlife Corridors

    Data.gov (United States)

    Vermont Center for Geographic Information — Habitat blocks are areas of contiguous forest and other natural habitats that are unfragmented by roads, development, or agriculture. Vermonts habitat blocks are...

  10. PWR systems transient analysis

    International Nuclear Information System (INIS)

    Kennedy, M.F.; Peeler, G.B.; Abramson, P.B.

    1985-01-01

    Analysis of transients in pressurized water reactor (PWR) systems involves the assessment of the response of the total plant, including primary and secondary coolant systems, steam piping and turbine (possibly including the complete feedwater train), and various control and safety systems. Transient analysis is performed as part of the plant safety analysis to insure the adequacy of the reactor design and operating procedures and to verify the applicable plant emergency guidelines. Event sequences which must be examined are developed by considering possible failures or maloperations of plant components. These vary in severity (and calculational difficulty) from a series of normal operational transients, such as minor load changes, reactor trips, valve and pump malfunctions, up to the double-ended guillotine rupture of a primary reactor coolant system pipe known as a Large Break Loss of Coolant Accident (LBLOCA). The focus of this paper is the analysis of all those transients and accidents except loss of coolant accidents

  11. Transients: The regulator's view

    International Nuclear Information System (INIS)

    Sheron, B.W.; Speis, T.P.

    1984-01-01

    This chapter attempts to clarify the basis for the regulator's concerns for transient events. Transients are defined as both anticipated operational occurrences and postulated accidents. Recent operational experience, supplemented by improved probabilistic risk analysis methods, has demonstrated that non-LOCA transient events can be significant contributors to overall risk. Topics considered include lessons learned from events and issues, the regulations governing plant transients, multiple failures, different failure frequencies, operator errors, and public pressure. It is concluded that the formation of Owners Groups and Regulatory Response Groups within the owners groups are positive signs of the industry's concern for safety and responsible dealing with the issues affecting both the US NRC and the industry

  12. Transient multivariable sensor evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Vilim, Richard B.; Heifetz, Alexander

    2017-02-21

    A method and system for performing transient multivariable sensor evaluation. The method and system includes a computer system for identifying a model form, providing training measurement data, generating a basis vector, monitoring system data from sensor, loading the system data in a non-transient memory, performing an estimation to provide desired data and comparing the system data to the desired data and outputting an alarm for a defective sensor.

  13. The soil and plant determinants of community structures of the dominant actinobacteria in Marion Island terrestrial habitats, Sub-Antarctica

    CSIR Research Space (South Africa)

    Sanyika, TW

    2012-08-01

    Full Text Available Marion Island is a Sub-Antarctic island made up of distinct ecological habitats based on soil physiochemical, plant cover and physical characteristics. The microbial diversity and ecological determinants in this harsh Sub-Antarctic environment...

  14. Subseafloor basalts as fungal habitats

    Directory of Open Access Journals (Sweden)

    M. Ivarsson

    2012-09-01

    Full Text Available The oceanic crust is believed to host the largest potential habitat for microbial life on Earth, yet, still we lack substantial information about the abundance, diversity, and consequence of its biosphere. The last two decades have involved major research accomplishments within this field and a change in view of the ocean crust and its potential to harbour life. Here fossilised fungal colonies in subseafloor basalts are reported from three different seamounts in the Pacific Ocean. The fungal colonies consist of various characteristic structures interpreted as fungal hyphae, fruit bodies and spores. The fungal hyphae are well preserved with morphological characteristics such as hyphal walls, septa, thallic conidiogenesis, and hyphal tips with hyphal vesicles within. The fruit bodies consist of large (∼50–200 µm in diameter body-like structures with a defined outer membrane and an interior filled with calcite. The fruit bodies have at some stage been emptied of their contents of spores and filled by carbonate-forming fluids. A few fruit bodies not filled by calcite and with spores still within support this interpretation. Spore-like structures (ranging from a few µm to ∼20 µm in diameter are also observed outside of the fruit bodies and in some cases concentrated to openings in the membrane of the fruit bodies. The hyphae, fruit bodies and spores are all closely associated with a crust lining the vein walls that probably represent a mineralized biofilm. The results support a fungal presence in deep subseafloor basalts and indicate that such habitats were vital between ∼81 and 48 Ma.

  15. Designated Critical Habitat

    Data.gov (United States)

    Kansas Data Access and Support Center — Critical habitats include those areas documented as currently supporting self-sustaining populations of any threatened or endangered species of wildlife as well as...

  16. VT Wildlife Linkage Habitat

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) The Wildlife Linkage Habitat Analysis uses landscape scale data to identify or predict the location of potentially significant wildlife linkage...

  17. Deep Space Habitat Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Deep Space Habitat was closed out at the end of Fiscal Year 2013 (September 30, 2013). Results and select content have been incorporated into the new Exploration...

  18. Smalltooth Sawfish Critical Habitat

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data represent the critical habitat for smalltooth sawfish (Pristis pectinatat) as designated by 74 FR 45353, September 2, 2009, Rules and Regulations.

  19. Right Whale Critical Habitat

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data represent the critical habitat for Right Whale as designated by Federal Register Vol. 59, No. 28805, May 19, 1993, Rules and Regulations.

  20. Johnsons Seagrass Critical Habitat

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data represent the critical habitat for Johnson's Seagrass as designated by Federal Register Vol. 65, No. 66, Wednesday, April 5, 2000, Rules and Regulations.

  1. Green Turtle Critical Habitat

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data represent the critical habitat for green turtle as designated by Federal Register Vol. 63, No. 46701, September 2, 1998, Rules and Regulations.

  2. Habitat Mapping Camera (HABCAM)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset entails imagery collected using the HabCam towed underwater vehicle and annotated data on objects or habitats in the images and notes on image...

  3. Macrofaunal communities associated with chemosynthetic habitats from the U.S. Atlantic margin: A comparison among depth and habitat types

    Science.gov (United States)

    Bourque, Jill R.; Robertson, Craig M.; Brooke, Sandra; Demopoulos, Amanda W.J.

    2016-01-01

    Hydrocarbon seeps support distinct benthic communities capable of tolerating extreme environmental conditions and utilizing reduced chemical compounds for nutrition. In recent years, several locations of methane seepage have been mapped along the U.S. Atlantic continental slope. In 2012 and 2013, two newly discovered seeps were investigated in this region: a shallow site near Baltimore Canyon (BCS, 366–412 m) and a deep site near Norfolk Canyon (NCS, 1467–1602 m), with both sites containing extensive chemosynthetic mussel bed and microbial mat habitats. Sediment push cores, suction samples, and Ekman box cores were collected to quantify the abundance, diversity, and community structure of benthic macrofauna (>300 μm) in mussel beds, mats, and slope habitats at both sites. Community data from the deep site were also assessed in relation to the associated sediment environment (organic carbon and nitrogen, stable carbon and nitrogen isotopes, grain size, and depth). Infaunal assemblages and densities differed both between depths and among habitat types. Macrofaunal densities in microbial mats were four times greater than those present in mussel beds and slope sediments and were dominated by the annelid families Dorvilleidae, Capitellidae, and Tubificidae, while mussel habitats had higher proportions of crustaceans. Diversity was lower in BCS microbial mat habitats, but higher in mussel and slope sediments compared to NCS habitats. Multivariate statistical analysis revealed specific sediment properties as important for distinguishing the macrofaunal communities, including larger grain sizes present within NCS microbial mat habitats and depleted stable carbon isotopes (δ13C) in sediments present at mussel beds. These results suggest that habitat differences in the quality and source of organic matter are driving the observed patterns in the infaunal assemblages, including high β diversity and high variability in the macrofaunal community composition. This

  4. Microbial effects

    International Nuclear Information System (INIS)

    Sharpe, V.J.

    1985-10-01

    The long term safety and integrity of radioactive waste disposal sites proposed for use by Ontario Hydro may be affected by the release of radioactive gases. Microbes mediate the primary pathways of waste degradation and hence an assessment of their potential to produce gaseous end products from the breakdown of low level waste was performed. Due to a number of unknown variables, assumptions were made regarding environmental and waste conditions that controlled microbial activity; however, it was concluded that 14 C and 3 H would be produced, albeit over a long time scale of about 1500 years for 14 C in the worst case situation

  5. Transient flow combustion

    Science.gov (United States)

    Tacina, R. R.

    1984-01-01

    Non-steady combustion problems can result from engine sources such as accelerations, decelerations, nozzle adjustments, augmentor ignition, and air perturbations into and out of the compressor. Also non-steady combustion can be generated internally from combustion instability or self-induced oscillations. A premixed-prevaporized combustor would be particularly sensitive to flow transients because of its susceptability to flashback-autoignition and blowout. An experimental program, the Transient Flow Combustion Study is in progress to study the effects of air and fuel flow transients on a premixed-prevaporized combustor. Preliminary tests performed at an inlet air temperature of 600 K, a reference velocity of 30 m/s, and a pressure of 700 kPa. The airflow was reduced to 1/3 of its original value in a 40 ms ramp before flashback occurred. Ramping the airflow up has shown that blowout is more sensitive than flashback to flow transients. Blowout occurred with a 25 percent increase in airflow (at a constant fuel-air ratio) in a 20 ms ramp. Combustion resonance was found at some conditions and may be important in determining the effects of flow transients.

  6. Transient hardened power FETs

    International Nuclear Information System (INIS)

    Dawes, W.R. Jr.; Fischer, T.A.; Huang, C.C.C.; Meyer, W.J.; Smith, C.S.; Blanchard, R.A.; Fortier, T.J.

    1986-01-01

    N-channel power FETs offer significant advantages in power conditioning circuits. Similiarily to all MOS technologies, power FET devices are vulnerable to ionizing radiation, and are particularily susceptible to burn-out in high dose rate irradiations (>1E10 rads(Si)/sec.), which precludes their use in many military environments. This paper will summarize the physical mechanisms responsible for burn-out, and discuss various fabrication techniques designed to improve the transient hardness of power FETs. Power FET devices were fabricated with several of these techniques, and data will be presented which demonstrates that transient hardness levels in excess of 1E12 rads(Si)/sec. are easily achievable

  7. Transients in the Vivitron

    International Nuclear Information System (INIS)

    Cooke, C.M.; Frick, G.; Roumie, M.

    1993-01-01

    Electrical measurements are presented for the construction of a model for the study of transients in the Vivitron. Observation of the transmission of electrical pulses in the porticos clearly shows transmission-line behaviour. Measurements of the vector impedance of the outer porticos show the same transmission-line properties, but also gives a description of the modification from a pure transmission line due to the circular electrodes. The results of this investigation should allow the construction of a computer model which predicts the evolution of the transients in the case of a spark in the Vivitron. (orig.)

  8. Transient Heat Conduction

    DEFF Research Database (Denmark)

    Rode, Carsten

    1998-01-01

    Analytical theory of transient heat conduction.Fourier's law. General heat conducation equation. Thermal diffusivity. Biot and Fourier numbers. Lumped analysis and time constant. Semi-infinite body: fixed surface temperature, convective heat transfer at the surface, or constant surface heat flux...

  9. Transient cavitation in pipelines

    NARCIS (Netherlands)

    Kranenburg, C.

    1974-01-01

    The aim of the present study is to set up a one-dimensional mathematical model, which describes the transient flow in pipelines, taking into account the influence of cavitation and free gas. The flow will be conceived of as a three-phase flow of the liquid, its vapour and non-condensible gas. The

  10. Compressive Transient Imaging

    KAUST Repository

    Sun, Qilin

    2017-04-01

    High resolution transient/3D imaging technology is of high interest in both scientific research and commercial application. Nowadays, all of the transient imaging methods suffer from low resolution or time consuming mechanical scanning. We proposed a new method based on TCSPC and Compressive Sensing to achieve a high resolution transient imaging with a several seconds capturing process. Picosecond laser sends a serious of equal interval pulse while synchronized SPAD camera\\'s detecting gate window has a precise phase delay at each cycle. After capturing enough points, we are able to make up a whole signal. By inserting a DMD device into the system, we are able to modulate all the frames of data using binary random patterns to reconstruct a super resolution transient/3D image later. Because the low fill factor of SPAD sensor will make a compressive sensing scenario ill-conditioned, We designed and fabricated a diffractive microlens array. We proposed a new CS reconstruction algorithm which is able to denoise at the same time for the measurements suffering from Poisson noise. Instead of a single SPAD senor, we chose a SPAD array because it can drastically reduce the requirement for the number of measurements and its reconstruction time. Further more, it not easy to reconstruct a high resolution image with only one single sensor while for an array, it just needs to reconstruct small patches and a few measurements. In this thesis, we evaluated the reconstruction methods using both clean measurements and the version corrupted by Poisson noise. The results show how the integration over the layers influence the image quality and our algorithm works well while the measurements suffer from non-trival Poisson noise. It\\'s a breakthrough in the areas of both transient imaging and compressive sensing.

  11. Microbial lifestyles that enable survival in lithifying habitats

    DEFF Research Database (Denmark)

    Tamez-Hidalgo, Paulina

    2010-01-01

    , ion chromatographic and ICP-MS analyses of the major solutes and for ANC titration. Temperature, conductivity and pH were measured at the sampling sites. A pyrotagged 16S rRNA gene sequencing approach at both sites was used along with a publicly accessible metagenome of a similar site at the same...... for carbon fixation. Surprisingly, genes for RubisCo appear to be absent. Almost all genes found for enzymes that catalyze the conversion of sulfur compounds are involved in aerobic oxidation pathways. The stoichiometric balance of these pathways leads to ANC decreases and to carbonate dissolution. Although...

  12. Microbial mat ecosystems: Structure types, functional diversity, and biotechnological application

    Directory of Open Access Journals (Sweden)

    Cristina M. Prieto-Barajas

    2018-01-01

    Full Text Available Microbial mats are horizontally stratified microbial communities, exhibiting a structure defined by physiochemical gradients, which models microbial diversity, physiological activities, and their dynamics as a whole system. These ecosystems are commonly associated with aquatic habitats, including hot springs, hypersaline ponds, and intertidal coastal zones and oligotrophic environments, all of them harbour phototrophic mats and other environments such as acidic hot springs or acid mine drainage harbour non-photosynthetic mats. This review analyses the complex structure, diversity, and interactions between the microorganisms that form the framework of different types of microbial mats located around the globe. Furthermore, the many tools that allow studying microbial mats in depth and their potential biotechnological applications are discussed.

  13. Saproxylic Hemiptera Habitat Associations

    Science.gov (United States)

    Michael D. Ulyshen; James L. Hanula; Robert L. Blinn; Gene. Kritsky

    2012-01-01

    Understanding the habitat requirements of organisms associated with dead wood is important in order to conserve them in managed forests. Unfortunately, many of the less diverse saproxylic taxa, including Hemiptera, remain largely unstudied. An effort to rear insects from dead wood taken from two forest types (an upland pine-dominated and a bottomland mixed hardwood),...

  14. Transient osteoporosis of hip

    Directory of Open Access Journals (Sweden)

    Mahesh M Choudhary

    2015-01-01

    Full Text Available We report a case of transient osteoporosis of the hip (TOH in a 50-year-old man including the clinical presentation, diagnostic studies, management, and clinical progress. TOH is a rare self-limiting condition that typically affects middle-aged men or, less frequently, women in the third trimester of pregnancy. Affected individuals present clinically with acute hip pain, limping gait, and limited ranges of hip motion. TOH may begin spontaneously or after a minor trauma. Radiographs are typically unremarkable but magnetic resonance (MR imaging studies yield findings consistent with bone marrow edema. TOH is referred to as regional migratory osteoporosis (RMO if it travels to other joints or the contralateral hip. TOH often resembles osteonecrosis but the two conditions must be differentiated due to different prognoses and management approaches. The term TOH is often used interchangeably and synonymously with transient bone marrow edema (TBME.

  15. Timing of global regression and microbial bloom linked with the Permian-Triassic boundary mass extinction: implications for driving mechanisms.

    Science.gov (United States)

    Baresel, Björn; Bucher, Hugo; Bagherpour, Borhan; Brosse, Morgane; Guodun, Kuang; Schaltegger, Urs

    2017-03-06

    New high-resolution U-Pb dates indicate a duration of 89 ± 38 kyr for the Permian hiatus and of 14 ± 57 kyr for the overlying Triassic microbial limestone in shallow water settings of the Nanpanjiang Basin, South China. The age and duration of the hiatus coincides with the Permian-Triassic boundary (PTB) and the extinction interval in the Meishan Global Stratotype Section and Point, and strongly supports a glacio-eustatic regression, which best explains the genesis of the worldwide hiatus straddling the PTB in shallow water records. In adjacent deep marine troughs, rates of sediment accumulation display a six-fold decrease across the PTB compatible with a dryer and cooler climate as indicated by terrestrial plants. Our model of the Permian-Triassic boundary mass extinction (PTBME) hinges on the synchronicity of the hiatus with the onset of the Siberian Traps volcanism. This early eruptive phase released sulfur-rich volatiles into the stratosphere, thus simultaneously eliciting a short-lived ice age responsible for the global regression and a brief but intense acidification. Abrupt cooling, shrunk habitats on shelves and acidification may all have synergistically triggered the PTBME. Subsequently, the build-up of volcanic CO 2 induced a transient cool climate whose early phase saw the deposition of the microbial limestone.

  16. Studies about behavior of microbial degradation of organic compounds

    International Nuclear Information System (INIS)

    Ohtsuka, Makiko

    2003-02-01

    Some of TRU waste include organic compounds, thus these organic compounds might be nutrients for microbial growth at disposal site. This disposal system might be exposed to high alkali condition by cement compounds as engineering barrier material. In the former experimental studies, it has been supposed that microbial exist under pH = 12 and the microbial activity acclimated to high alkali condition are able to degrade asphalt under anaerobic condition. Microbes are called extremophile that exist in cruel habitat as high alkali or reductive condition. We know less information about the activity of extremophile, though any recent studies reveal them. In this study, the first investigation is metabolic pathway as microbial activity, the second is microbial degradation of aromatic compounds in anaerobic condition, and the third is microbial activity under high alkali. Microbial metabolic pathway consist of two systems that fulfill their function each other. One system is to generate energy for microbial activities and the other is to convert substances for syntheses of organisms' structure materials. As these systems are based on redox reaction between substances, it is made chart of the microbial activity region using pH, Eh, and depth as parameter, There is much report that microbe is able to degrade aromatic compounds under aerobic or molecular O 2 utilizing condition. For degradation of aromatic compounds in anaerobic condition, supplying electron acceptor is required. Co-metabolism and microbial consortia has important role, too. Alcalophile has individual transporting system depending Na + and acidic compounds contained in cell wall. Generating energy is key for survival and growth under high alkali condition. Co-metabolism and microbial consortia are effective for microbial degradation of aromatic compounds under high alkali and reductive condition, and utilizable electron acceptor and degradable organic compounds are required for keeping microbial activity and

  17. Stability of Ignition Transients

    OpenAIRE

    V.E. Zarko

    1991-01-01

    The problem of ignition stability arises in the case of the action of intense external heat stimuli when, resulting from the cut-off of solid substance heating, momentary ignition is followed by extinction. Physical pattern of solid propellant ignition is considered and ignition criteria available in the literature are discussed. It is shown that the above mentioned problem amounts to transient burning at a given arbitrary temperature distribution in the condensed phase. A brief survey...

  18. Transient FDTD simulation validation

    OpenAIRE

    Jauregui Tellería, Ricardo; Riu Costa, Pere Joan; Silva Martínez, Fernando

    2010-01-01

    In computational electromagnetic simulations, most validation methods have been developed until now to be used in the frequency domain. However, the EMC analysis of the systems in the frequency domain many times is not enough to evaluate the immunity of current communication devices. Based on several studies, in this paper we propose an alternative method of validation of the transients in time domain allowing a rapid and objective quantification of the simulations results.

  19. NEPR Benthic Habitat Map 2015

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This benthic habitat map was created from a semi-automated habitat mapping process, using a combination of bathymetry, satellite imagery, aerial imagery and...

  20. NORTHWOODS Wildlife Habitat Data Base

    Science.gov (United States)

    Mark D. Nelson; Janine M. Benyus; Richard R. Buech

    1992-01-01

    Wildlife habitat data from seven Great Lakes National Forests were combined into a wildlife-habitat matrix named NORTHWOODS. Several electronic file formats of NORTHWOODS data base and documentation are available on floppy disks for microcomputers.

  1. MHD aspects of coronal transients

    International Nuclear Information System (INIS)

    Anzer, U.

    1979-10-01

    If one defines coronal transients as events which occur in the solar corona on rapid time scales (< approx. several hours) then one would have to include a large variety of solar phenomena: flares, sprays, erupting prominences, X-ray transients, white light transients, etc. Here we shall focus our attention on the latter two phenomena. (orig.) 891 WL/orig. 892 RDG

  2. Environmental Monitoring as Part of Life Support for the Crew Habitat for Lunar and Mars Missions

    Science.gov (United States)

    Jan, Darrell L.

    2010-01-01

    Like other crewed space missions, future missions to the moon and Mars will have requirements for monitoring the chemical and microbial status of the crew habitat. Monitoring the crew habitat becomes more critical in such long term missions. This paper will describe the state of technology development for environmental monitoring of lunar lander and lunar outpost missions, and the state of plans for future missions.

  3. Microbial diversity in soil : Selection of microbial populations by plant and soil type and implications for disease suppressiveness

    NARCIS (Netherlands)

    Garbeva, P; van Veen, JA; van Elsas, JD

    2004-01-01

    An increasing interest has emerged with respect to the importance of microbial diversity in soil habitats. The extent of the diversity of microorganisms in soil is seen to be critical to the maintenance of soil health and quality, as a wide range of microorganisms is involved in important soil

  4. Microbial micropatches within microbial hotspots

    Science.gov (United States)

    Smith, Renee J.; Tobe, Shanan S.; Paterson, James S.; Seymour, Justin R.; Oliver, Rod L.; Mitchell, James G.

    2018-01-01

    The spatial distributions of organism abundance and diversity are often heterogeneous. This includes the sub-centimetre distributions of microbes, which have ‘hotspots’ of high abundance, and ‘coldspots’ of low abundance. Previously we showed that 300 μl abundance hotspots, coldspots and background regions were distinct at all taxonomic levels. Here we build on these results by showing taxonomic micropatches within these 300 μl microscale hotspots, coldspots and background regions at the 1 μl scale. This heterogeneity among 1 μl subsamples was driven by heightened abundance of specific genera. The micropatches were most pronounced within hotspots. Micropatches were dominated by Pseudomonas, Bacteroides, Parasporobacterium and Lachnospiraceae incertae sedis, with Pseudomonas and Bacteroides being responsible for a shift in the most dominant genera in individual hotspot subsamples, representing up to 80.6% and 47.3% average abundance, respectively. The presence of these micropatches implies the ability these groups have to create, establish themselves in, or exploit heterogeneous microenvironments. These genera are often particle-associated, from which we infer that these micropatches are evidence for sub-millimetre aggregates and the aquatic polymer matrix. These findings support the emerging paradigm that the microscale distributions of planktonic microbes are numerically and taxonomically heterogeneous at scales of millimetres and less. We show that microscale microbial hotspots have internal structure within which specific local nutrient exchanges and cellular interactions might occur. PMID:29787564

  5. Sound solutions for habitat monitoring

    Science.gov (United States)

    Mary M. Rowland; Lowell H. Suring; Christina D. Vojta

    2015-01-01

    For agencies and organizations to effectively manage wildlife, knowledge about the status and trend of wildlife habitat is critical. Traditional wildlife monitoring, however, has focused on populations rather than habitat, because ultimately population status drives long-term species viability. Still, habitat loss has contributed to the decline of nearly all at-risk...

  6. Microbial community changes along the active seepage site of one cold seep in the Red Sea.

    KAUST Repository

    Cao, Huiluo

    2015-07-21

    The active seepage of the marine cold seeps could be a critical process for the exchange of energy between the submerged geosphere and the sea floor environment through organic-rich fluids, potentially even affecting surrounding microbial habitats. However, few studies have investigated the associated microbial community changes. In the present study, 16S rRNA genes were pyrosequenced to decipher changes in the microbial communities from the Thuwal seepage point in the Red Sea to nearby marine sediments in the brine pool, normal marine sediments and water, and benthic microbial mats. An unexpected number of reads from unclassified groups were detected in these habitats; however, the ecological functions of these groups remain unresolved. Furthermore, ammonia-oxidizing archaeal community structures were investigated using the ammonia monooxygenase subunit A (amoA) gene. Analysis of amoA showed that planktonic marine habitats, including seeps and marine water, hosted archaeal ammonia oxidizers that differed from those in microbial mats and marine sediments, suggesting modifications of the ammonia oxidizing archaeal (AOA) communities along the environmental gradient from active seepage sites to peripheral areas. Changes in the microbial community structure of AOA in different habitats (water vs. sediment) potentially correlated with changes in salinity and oxygen concentrations. Overall, the present results revealed for the first time unanticipated novel microbial groups and changes in the ammonia-oxidizing archaea in response to environmental gradients near the active seepages of a cold seep.

  7. Microbial community changes along the active seepage site of one cold seep in the Red Sea.

    KAUST Repository

    Cao, Huiluo; Zhang, Weipeng; Wang, Yong; Qian, Pei-Yuan

    2015-01-01

    The active seepage of the marine cold seeps could be a critical process for the exchange of energy between the submerged geosphere and the sea floor environment through organic-rich fluids, potentially even affecting surrounding microbial habitats. However, few studies have investigated the associated microbial community changes. In the present study, 16S rRNA genes were pyrosequenced to decipher changes in the microbial communities from the Thuwal seepage point in the Red Sea to nearby marine sediments in the brine pool, normal marine sediments and water, and benthic microbial mats. An unexpected number of reads from unclassified groups were detected in these habitats; however, the ecological functions of these groups remain unresolved. Furthermore, ammonia-oxidizing archaeal community structures were investigated using the ammonia monooxygenase subunit A (amoA) gene. Analysis of amoA showed that planktonic marine habitats, including seeps and marine water, hosted archaeal ammonia oxidizers that differed from those in microbial mats and marine sediments, suggesting modifications of the ammonia oxidizing archaeal (AOA) communities along the environmental gradient from active seepage sites to peripheral areas. Changes in the microbial community structure of AOA in different habitats (water vs. sediment) potentially correlated with changes in salinity and oxygen concentrations. Overall, the present results revealed for the first time unanticipated novel microbial groups and changes in the ammonia-oxidizing archaea in response to environmental gradients near the active seepages of a cold seep.

  8. Habitat Use Database - Groundfish Essential Fish Habitat (EFH) Habitat Use Database (HUD)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Habitat Use Database (HUD) was specifically designed to address the need for habitat-use analyses in support of groundfish EFH, HAPCs, and fishing and nonfishing...

  9. Magnetic transients in flares

    International Nuclear Information System (INIS)

    Zirin, H.; Tanaka, K.

    1981-01-01

    We present data on magnetic transients (mgtr's) observed in flares on 1980 July 1 and 5 with Big Bear videomagnetograph (VMG). The 1980 July 1 event was a white light flare in which a strong bipolar mgtr was observed, and a definite change in the sunspots occurred at the time of the flare. In the 1980 July 5 flare, a mgtr was observed in only one polarity, and, although no sunspot changes occurred simultaneous with the flare, major spot changes occurred in a period of hours

  10. Familial Transient Global Amnesia

    Directory of Open Access Journals (Sweden)

    R.Rhys Davies

    2012-12-01

    Full Text Available Following an episode of typical transient global amnesia (TGA, a female patient reported similar clinical attacks in 2 maternal aunts. Prior reports of familial TGA are few, and no previous account of affected relatives more distant than siblings or parents was discovered in a literature survey. The aetiology of familial TGA is unknown. A pathophysiological mechanism akin to that in migraine attacks, comorbidity reported in a number of the examples of familial TGA, is one possibility. The study of familial TGA cases might facilitate the understanding of TGA aetiology.

  11. Measurand transient signal suppressor

    Science.gov (United States)

    Bozeman, Richard J., Jr. (Inventor)

    1994-01-01

    A transient signal suppressor for use in a controls system which is adapted to respond to a change in a physical parameter whenever it crosses a predetermined threshold value in a selected direction of increasing or decreasing values with respect to the threshold value and is sustained for a selected discrete time interval is presented. The suppressor includes a sensor transducer for sensing the physical parameter and generating an electrical input signal whenever the sensed physical parameter crosses the threshold level in the selected direction. A manually operated switch is provided for adapting the suppressor to produce an output drive signal whenever the physical parameter crosses the threshold value in the selected direction of increasing or decreasing values. A time delay circuit is selectively adjustable for suppressing the transducer input signal for a preselected one of a plurality of available discrete suppression time and producing an output signal only if the input signal is sustained for a time greater than the selected suppression time. An electronic gate is coupled to receive the transducer input signal and the timer output signal and produce an output drive signal for energizing a control relay whenever the transducer input is a non-transient signal which is sustained beyond the selected time interval.

  12. Transient regional osteoporosis

    Directory of Open Access Journals (Sweden)

    F. Trotta

    2011-09-01

    Full Text Available Transient osteoporosis of the hip and regional migratory osteoporosis are uncommon and probably underdiagnosed bone diseases characterized by pain and functional limitation mainly affecting weight-bearing joints of the lower limbs. These conditions are usually self-limiting and symptoms tend to abate within a few months without sequelae. Routine laboratory investigations are unremarkable. Middle aged men and women during the last months of pregnancy or in the immediate post-partum period are principally affected. Osteopenia with preservation of articular space and transitory edema of the bone marrow provided by magnetic resonance imaging are common to these two conditions, so they are also known by the term regional transitory osteoporosis. The appearance of bone marrow edema is not specific to regional transitory osteoporosis but can be observed in several diseases, i.e. trauma, reflex sympathetic dystrophy, avascular osteonecrosis, infections, tumors from which it must be differentiated. The etiology of this condition is unknown. Pathogenesis is still debated in particular the relationship with reflex sympathetic dystrophy, with which regional transitory osteoporosis is often identified. The purpose of the present review is to remark on the relationship between transient osteoporosis of the hip and regional migratory osteoporosis with particular attention to the bone marrow edema pattern and relative differential diagnosis.

  13. 11 Soil Microbial Biomass

    African Journals Online (AJOL)

    186–198. Insam H. (1990). Are the soil microbial biomass and basal respiration governed by the climatic regime? Soil. Biol. Biochem. 22: 525–532. Insam H. D. and Domsch K. H. (1989). Influence of microclimate on soil microbial biomass. Soil Biol. Biochem. 21: 211–21. Jenkinson D. S. (1988). Determination of microbial.

  14. Molecular microbial ecology manual

    NARCIS (Netherlands)

    Kowalchuk, G.A.; Bruijn, de F.J.; Head, I.M.; Akkermans, A.D.L.

    2004-01-01

    The field of microbial ecology has been revolutionized in the past two decades by the introduction of molecular methods into the toolbox of the microbial ecologist. This molecular arsenal has helped to unveil the enormity of microbial diversity across the breadth of the earth's ecosystems, and has

  15. Microbial Rechargeable Battery

    NARCIS (Netherlands)

    Molenaar, Sam D.; Mol, Annemerel R.; Sleutels, Tom H.J.A.; Heijne, Ter Annemiek; Buisman, Cees J.N.

    2016-01-01

    Bioelectrochemical systems hold potential for both conversion of electricity into chemicals through microbial electrosynthesis (MES) and the provision of electrical power by oxidation of organics using microbial fuel cells (MFCs). This study provides a proof of concept for a microbial

  16. Childhood microbial keratitis

    Directory of Open Access Journals (Sweden)

    Abdullah G Al Otaibi

    2012-01-01

    Conclusion: Children with suspected microbial keratitis require comprehensive evaluation and management. Early recognition, identifying the predisposing factors and etiological microbial organisms, and instituting appropriate treatment measures have a crucial role in outcome. Ocular trauma was the leading cause of childhood microbial keratitis in our study.

  17. Manipulatiaon of Biofilm Microbial Ecology

    Energy Technology Data Exchange (ETDEWEB)

    Burkhalter, R.; Macnaughton, S.J.; Palmer, R.J.; Smith, C.A.; Whitaker, K.W.; White, D.C.; Zinn, M.; kirkegaard, R.

    1998-08-09

    The Biofilm mode of growth provides such significant advantages to the members of the consortium that most organisms in important habitats are found in biofilms. The study of factors that allow manipulation of biofilm microbes in the biofilm growth state requires that reproducible biofilms by generated. The most effective monitoring of biofilm formation, succession and desquamation is with on-line monitoring of microbial biofilms with flowcell for direct observation. The biofilm growth state incorporates a second important factor, the heterogeneity in the distribution in time and space of the component members of the biofilm consortium. This heterogeneity is reflected not only in the cellular distribution but in the metabolic activity within a population of cells. Activity and cellular distribution can be mapped in four dimensions with confocal microscopy, and function can be ascertained by genetically manipulated reporter functions for specific genes or by vital stains. The methodology for understanding the microbial ecology of biofilms is now much more readily available and the capacity to manipulate biofilms is becoming an important feature of biotechnology.

  18. Manipulation of Biofilm Microbial Ecology

    Energy Technology Data Exchange (ETDEWEB)

    White, D.C.; Palmer, R.J., Jr.; Zinn, M.; Smith, C.A.; Burkhalter, R.; Macnaughton, S.J.; Whitaker, K.W.; Kirkegaard, R.D.

    1998-08-15

    The biofilm mode of growth provides such significant advantages to the members of the consortium that most organisms in important habitats are found in biofilms. The study of factors that allow manipulation of biofilm microbes in the biofilm growth state requires that reproducible biofilms be generated. The most effective monitoring of biofilm formation, succession and desaturation is with on-line monitoring of microbial biofilms with flowcell for direct observation. The biofilm growth state incorporates a second important factor, the heterogeneity in distribution in time and space of the component members of the biofilm consortium. This heterogeneity is reflected not only in the cellular distribution but in the metabolic activity within a population of cells. Activity and cellular distribution can be mapped in four dimensions with confocal microscopy, and function can be ascertained by genetically manipulated reporter functions for specific genes or by vital stains. The methodology for understanding the microbial ecology of biofilms is now much more readily available and the capacity to manipulate biofilms is becoming an important feature of biotechnology.

  19. Lichens of neglected habitats in Eastern and East-Central European lowlands

    Directory of Open Access Journals (Sweden)

    Jurga Motiejūnaitē

    2013-12-01

    Full Text Available Situation of lichens of aquatic and transient habitats in Eastern and East-Central European lowlands is discussed basing on example of several selected species: Leptogium biatorinum, Sarcosagium campestre, Steinia geophana, Verrucaria aquatilis, V. hydrela, V. praetermissa, V. xyloxena. Both habitat types are generally very much neglected in the region and all species show large spatial gaps in recording, which makes it difficult to judge both about their true distribution limits and spreading dynamics. On the other hand, targeted search through the suitable habitats and abundance of such indicate that many of these lichens are probably not uncommon in the region.

  20. The joy of transient chaos

    Energy Technology Data Exchange (ETDEWEB)

    Tél, Tamás [Institute for Theoretical Physics, Eötvös University, and MTA-ELTE Theoretical Physics Research Group, Pázmány P. s. 1/A, Budapest H-1117 (Hungary)

    2015-09-15

    We intend to show that transient chaos is a very appealing, but still not widely appreciated, subfield of nonlinear dynamics. Besides flashing its basic properties and giving a brief overview of the many applications, a few recent transient-chaos-related subjects are introduced in some detail. These include the dynamics of decision making, dispersion, and sedimentation of volcanic ash, doubly transient chaos of undriven autonomous mechanical systems, and a dynamical systems approach to energy absorption or explosion.

  1. Transient osteoporosis of the hip

    International Nuclear Information System (INIS)

    McWalter, Patricia; Hassan Ahmed

    2007-01-01

    Transient osteoporosis of the hip is an uncommon cause of hip pain, mostly affecting healthy middle-aged men and also women in the third trimester of pregnancy. We present a case of transient osteoporosis of the hip in a 33-year-old non-pregnant female patient. This case highlights the importance of considering a diagnosis of transient osteoporosis of the hip in patients who present with hip pain. (author)

  2. The ZTF Bright Transient Survey

    Science.gov (United States)

    Fremling, C.; Sharma, Y.; Kulkarni, S. R.; Miller, A. A.; Taggart, K.; Perley, D. A.; Gooba, A.

    2018-06-01

    As a supplement to the Zwicky Transient Facility (ZTF; ATel #11266) public alerts (ATel #11685) we plan to report (following ATel #11615) bright probable supernovae identified in the raw alert stream from the ZTF Northern Sky Survey ("Celestial Cinematography"; see Bellm & Kulkarni, 2017, Nature Astronomy 1, 71) to the Transient Name Server (https://wis-tns.weizmann.ac.il) on a daily basis; the ZTF Bright Transient Survey (BTS; see Kulkarni et al., 2018; arXiv:1710.04223).

  3. The joy of transient chaos.

    Science.gov (United States)

    Tél, Tamás

    2015-09-01

    We intend to show that transient chaos is a very appealing, but still not widely appreciated, subfield of nonlinear dynamics. Besides flashing its basic properties and giving a brief overview of the many applications, a few recent transient-chaos-related subjects are introduced in some detail. These include the dynamics of decision making, dispersion, and sedimentation of volcanic ash, doubly transient chaos of undriven autonomous mechanical systems, and a dynamical systems approach to energy absorption or explosion.

  4. Transient Infrared Emission Spectroscopy

    Science.gov (United States)

    Jones, Roger W.; McClelland, John F.

    1989-12-01

    Transient Infrared Emission Spectroscopy (TIRES) is a new technique that reduces the occurrence of self-absorption in optically thick solid samples so that analytically useful emission spectra may be observed. Conventional emission spectroscopy, in which the sample is held at an elevated, uniform temperature, is practical only for optically thin samples. In thick samples the emission from deep layers of the material is partially absorbed by overlying layers.1 This self-absorption results in emission spectra from most optically thick samples that closely resemble black-body spectra. The characteristic discrete emission bands are severely truncated and altered in shape. TIRES bypasses this difficulty by using a laser to heat only an optically thin surface layer. The increased temperature of the layer is transient since the layer will rapidly cool and thicken by thermal diffusion; hence the emission collection must be correlated with the laser heating. TIRES may be done with both pulsed and cw lasers.2,3 When a pulsed laser is used, the spectrometer sampling must be synchronized with the laser pulsing so that only emission during and immediately after each laser pulse is observed.3 If a cw laser is used, the sample must move rapidly through the beam. The hot, transient layer is then in the beam track on the sample at and immediately behind the beam position, so the spectrometer field of view must be limited to this region near the beam position.2 How much self-absorption the observed emission suffers depends on how thick the heated layer has grown by thermal diffusion when the spectrometer samples the emission. Use of a pulsed laser synchronized with the spectrometer sampling readily permits reduction of the time available for heat diffusion to about 100 acs .3 When a cw laser is used, the heat-diffusion time is controlled by how small the spectrometer field of view is and by how rapidly the sample moves past within this field. Both a very small field of view and a

  5. Plant Habitat (PH)

    Science.gov (United States)

    Onate, Bryan

    2016-01-01

    The International Space Station (ISS) will soon have a platform for conducting fundamental research of Large Plants. Plant Habitat (PH) is designed to be a fully controllable environment for high-quality plant physiological research. PH will control light quality, level, and timing, temperature, CO2, relative humidity, and irrigation, while scrubbing ethylene. Additional capabilities include leaf temperature and root zone moisture and oxygen sensing. The light cap will have red (630 nm), blue (450 nm), green (525 nm), far red (730 nm) and broad spectrum white LEDs. There will be several internal cameras (visible and IR) to monitor and record plant growth and operations.

  6. Anticipated transients without scram

    International Nuclear Information System (INIS)

    Lellouche, G.S.

    1980-01-01

    This article discusses in various degrees of depth the publications WASH-1270, WASH-1400, and NUREG-0460, and has as its purpose a description of the technical work done by Electric Power Research Institute (EPRI) personnel and its contractors on the subject of anticipated transients without scram (ATWS). It demonstrates the close relation between the probability of scram failure derived from historical scram data and that derived from the use of component data in a model of a system (the so-called synthesis method), such as was done in WASH-1400. The inherent conservatism of these models is demonstrated by showing that they predict significantly more events than have in fact occurred and that such models still predict scram failure probabilities low enough to make ATWS an insignificant contributor to accident risk

  7. Transient fuel melting

    International Nuclear Information System (INIS)

    Roche, L.; Schmitz, F.

    1982-10-01

    The observation of micrographic documents from fuel after a CABRI test leads to postulate a specific mode of transient fuel melting during a rapid nuclear power excursion. When reaching the melt threshold, the bands which are characteristic for the solid state are broken statistically over a macroscopic region. The time of maintaining the fuel at the critical enthalpy level between solid and liquid is too short to lead to a phase separation. A significant life-time (approximately 1 second) of this intermediate ''unsolide'' state would have consequences on the variation of physical properties linked to the phase transition solid/liquid: viscosity, specific volume and (for the irradiated fuel) fission gas release [fr

  8. Transient osteoporosis of pregnancy.

    Science.gov (United States)

    Maliha, George; Morgan, Jordan; Vrahas, Mark

    2012-08-01

    Transient osteoporosis of pregnancy (TOP) is a rare yet perhaps under-reported condition that has affected otherwise healthy pregnancies throughout the world. The condition presents suddenly in the third trimester of a usually uneventful pregnancy and progressively immobilizes the mother. Radiographic studies detect drastic loss of bone mass, elevated rates of turnover in the bone, and oedema in the affected portion. Weakness of the bone can lead to fractures during delivery and other complications for the mother. Then, within weeks of labour, symptoms and radiological findings resolve. Aetiology is currently unknown, although neural, vascular, haematological, endocrine, nutrient-deficiency, and other etiologies have been proposed. Several treatments have also been explored, including simple bed rest, steroids, bisphosphonates, calcitonin, induced termination of pregnancy, and surgical intervention. The orthopedist plays an essential role in monitoring the condition (and potential complications) as well as ensuring satisfactory outcomes for both the mother and newborn. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Vacant habitats in the Universe.

    Science.gov (United States)

    Cockell, Charles S

    2011-02-01

    The search for life on other planets usually makes the assumption that where there is a habitat, it will contain life. On the present-day Earth, uninhabited habitats (or vacant habitats) are rare, but might occur, for example, in subsurface oils or impact craters that have been thermally sterilized in the past. Beyond Earth, vacant habitats might similarly exist on inhabited planets or on uninhabited planets, for example on a habitable planet where life never originated. The hypothesis that vacant habitats are abundant in the Universe is testable by studying other planets. In this review, I discuss how the study of vacant habitats might ultimately inform an understanding of how life has influenced geochemical conditions on Earth. Copyright © 2010 Elsevier Ltd. All rights reserved.

  10. Microbial activity in the terrestrial subsurface

    International Nuclear Information System (INIS)

    Kaiser, J.P.; Bollag, J.M.

    1990-01-01

    Little is known about the layers under the earth's crust. Only in recent years have techniques for sampling the deeper subsurface been developed to permit investigation of the subsurface environment. Prevailing conditions in the subsurface habitat such as nutrient availability, soil composition, redox potential, permeability and a variety of other factors can influence the microflora that flourish in a given environment. Microbial diversity varies between geological formations, but in general sandy soils support growth better than soils rich in clay. Bacteria predominate in subsurface sediments, while eukaryotes constitute only 1-2% of the microorganisms. Recent investigations revealed that most uncontaminated subsurface soils support the growth of aerobic heteroorganotrophic bacteria, but obviously anaerobic microorganisms also exist in the deeper subsurface habitat. The microorganisms residing below the surface of the earth are capable of degrading both natural and xenobiotic contaminants and can thereby adapt to growth under polluted conditions. (author) 4 tabs, 77 refs

  11. Habitat segregation in fish assemblages

    OpenAIRE

    Ibbotson, A.T.

    1990-01-01

    The segregation of habitats of fish assemblages found in the chalk streams and rivers within the Wessex, South West and Southern Water Authority boundaries in southern England have been examined. Habitat segregation is the most frequent type of resource partitioning in natural communities. The habitat of individual fish species will be defined in order to determine the following: (1) the requirements of each species in terms of depth, current velocity, substrate, cover etc.; (2) identify the ...

  12. Transient Go: A Mobile App for Transient Astronomy Outreach

    Science.gov (United States)

    Crichton, D.; Mahabal, A.; Djorgovski, S. G.; Drake, A.; Early, J.; Ivezic, Z.; Jacoby, S.; Kanbur, S.

    2016-12-01

    Augmented Reality (AR) is set to revolutionize human interaction with the real world as demonstrated by the phenomenal success of `Pokemon Go'. That very technology can be used to rekindle the interest in science at the school level. We are in the process of developing a prototype app based on sky maps that will use AR to introduce different classes of astronomical transients to students as they are discovered i.e. in real-time. This will involve transient streams from surveys such as the Catalina Real-time Transient Survey (CRTS) today and the Large Synoptic Survey Telescope (LSST) in the near future. The transient streams will be combined with archival and latest image cut-outs and other auxiliary data as well as historical and statistical perspectives on each of the transient types being served. Such an app could easily be adapted to work with various NASA missions and NSF projects to enrich the student experience.

  13. Engineering chemical interactions in microbial communities.

    Science.gov (United States)

    Kenny, Douglas J; Balskus, Emily P

    2018-03-05

    Microbes living within host-associated microbial communities (microbiotas) rely on chemical communication to interact with surrounding organisms. These interactions serve many purposes, from supplying the multicellular host with nutrients to antagonizing invading pathogens, and breakdown of chemical signaling has potentially negative consequences for both the host and microbiota. Efforts to engineer microbes to take part in chemical interactions represent a promising strategy for modulating chemical signaling within these complex communities. In this review, we discuss prominent examples of chemical interactions found within host-associated microbial communities, with an emphasis on the plant-root microbiota and the intestinal microbiota of animals. We then highlight how an understanding of such interactions has guided efforts to engineer microbes to participate in chemical signaling in these habitats. We discuss engineering efforts in the context of chemical interactions that enable host colonization, promote host health, and exclude pathogens. Finally, we describe prominent challenges facing this field and propose new directions for future engineering efforts.

  14. Microbial Insights into Shifting Methane Production Potential in Thawing Permafrost

    Science.gov (United States)

    Crossen, K.; Wilson, R.; Raab, N.; Neumann, R.; Chanton, J.; Saleska, S. R.; Rich, V. I.

    2017-12-01

    Permafrost, which stores 50% of global soil carbon, is thawing rapidly due to climate change, and resident microbes are contributing to changing carbon gas emissions. Predictions of the fate of carbon in these regions is poorly constrained; however, improved, careful mapping of microbial community members influencing CO2 and CH4 emissions will help clarify the system response to continued change. In order to more fully understand connections between the microbial communities, major geochemical transformations, and CO2 and CH4 emissions, peat cores were collected from the active layers of three permafrost habitats spanning a thaw gradient (collapsed palsa, bog, and fen) at Stordalen Mire, Abisko, Sweden. Anaerobic incubations of shallow and deep subsamples from these sites were performed, with time-course characterization of the changes in microbial communities, peat geochemistry, and carbon gas production. The latter were profiled with 16S rRNA amplicon sequencing, and targeted metagenomes. The communities within each habitat and depth were statistically distinct, and changed significantly over the course of the incubations. Acidobacteria was consistently the dominant bacterial phylum in all three habitat types. With increased thaw, the relative abundance of Actinobacteria tended to decrease, while Chloroflexi and Bacteroidetes increased with thaw. The relative abundance of methanogens increased with thaw and with depth within each habitat. Over time in the incubations, the richness of the communities tended to decrease. Homoacetogenesis (CO2 + H2 -> CH3COOH) has been documented in other peatlands, and homoacetogens can influence CH4 production by interacting with methanogens, competing with hydrogenotrophs while providing substrate for acetoclasts. Modelling of microbial reaction networks suggests potential for highest homoacetogenesis rates in the collapsed palsa, which also contains the highest relative abundances of lineages taxonomically affiliated with known

  15. Manipulating soil microbial communities in extensive green roof substrates.

    Science.gov (United States)

    Molineux, Chloe J; Connop, Stuart P; Gange, Alan C

    2014-09-15

    There has been very little investigation into the soil microbial community on green roofs, yet this below ground habitat is vital for ecosystem functioning. Green roofs are often harsh environments that would greatly benefit from having a healthy microbial system, allowing efficient nutrient cycling and a degree of drought tolerance in dry summer months. To test if green roof microbial communities could be manipulated, we added mycorrhizal fungi and a microbial mixture ('compost tea') to green roof rootzones, composed mainly of crushed brick or crushed concrete. The study revealed that growing media type and depth play a vital role in the microbial ecology of green roofs. There are complex relationships between depth and type of substrate and the biomass of different microbial groups, with no clear pattern being observed. Following the addition of inoculants, bacterial groups tended to increase in biomass in shallower substrates, whereas fungal biomass change was dependent on depth and type of substrate. Increased fungal biomass was found in shallow plots containing more crushed concrete and deeper plots containing more crushed brick where compost tea (a live mixture of beneficial bacteria) was added, perhaps due to the presence of helper bacteria for arbuscular mycorrhizal fungi (AMF). Often there was not an additive affect of the microbial inoculations but instead an antagonistic interaction between the added AM fungi and the compost tea. This suggests that some species of microbes may not be compatible with others, as competition for limited resources occurs within the various substrates. The overall results suggest that microbial inoculations of green roof habitats are sustainable. They need only be done once for increased biomass to be found in subsequent years, indicating that this is a novel and viable method of enhancing roof community composition. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Predicting micro thermal habitat of lizards in a dynamic thermal environment

    NARCIS (Netherlands)

    Fei, T.; Skidmore, A.K.; Venus, V.; Wang, T.; Toxopeus, A.G.; Bian, B.M.; Liu, Y.

    2012-01-01

    Understanding behavioural thermoregulation and its consequences is a central topic in ecology. In this study, a spatial explicit model was developed to simulate the movement and thermal habitat use of lizards in a controlled environment. The model incorporates a lizard's transient body temperatures

  17. European red list of habitats. Part 1: Marine habitats

    NARCIS (Netherlands)

    Gubbay, S.; Sanders, N.; Haynes, T.; Janssen, J.A.M.; Rodwell, J.R.; Nieto, A.; Garcia Criado, M.; Beal, S.; Borg, J.

    2016-01-01

    The European Red List of Habitats provides an overview of the risk
    of collapse (degree of endangerment) of marine, terrestrial and
    freshwater habitats in the European Union (EU28) and adjacent
    regions (EU28+), based on a consistent set of categories and
    criteria, and detailed data

  18. Pressure transients in pipeline systems

    DEFF Research Database (Denmark)

    Voigt, Kristian

    1998-01-01

    This text is to give an overview of the necessary background to do investigation of pressure transients via simulations. It will describe briefly the Method of Characteristics which is the defacto standard for simulating pressure transients. Much of the text has been adopted from the book Pressur...

  19. Our cosmic habitat

    CERN Document Server

    Rees, Martin

    2001-01-01

    Our universe seems strangely 'biophilic,' or hospitable to life. Is this providence or coincidence? According to Martin Rees, the answer depends on the answer to another question, the one posed by Einstein's famous remark: 'What interests me most is whether God could have made the world differently.' This highly engaging book centres on the fascinating consequences of the answer being 'yes'. Rees explores the notion that our universe is just part of a vast 'multiverse,' or ensemble of universes, in which most of the other universes are lifeless. What we call the laws of nature would then be local by laws, imposed in the aftermath of our own Big Bang. In this scenario, our cosmic habitat would be a special, possibly unique universe where the prevailing laws of physics allowed life to emerge.

  20. Transient regional osteoporosis.

    Science.gov (United States)

    Cano-Marquina, Antonio; Tarín, Juan J; García-Pérez, Miguel-Ángel; Cano, Antonio

    2014-04-01

    Transient regional osteoporosis (TRO) is a disease that predisposes to fragility fracture in weight bearing joints of mid-life women and men. Pregnant women may also suffer the process, usually at the hip. The prevalence of TRO is lower than the systemic form, associated with postmenopause and advanced age, but may be falsely diminished by under-diagnosis. The disease may be uni- or bilateral, and may migrate to distinct joints. One main feature of TRO is spontaneous recovery. Pain and progressive limitation in the functionality of the affected joint(s) are key symptoms. In the case of the form associated with pregnancy, difficulties in diagnosis derive from the relatively young age at presentation and from the clinical overlapping with the frequent aches during gestation. Densitometric osteoporosis in the affected region is not always present, but bone marrow edema, with or without joint effusion, is detected by magnetic resonance. There are not treatment guidelines, but the association of antiresorptives to symptomatic treatment seems to be beneficial. Surgery or other orthopedic interventions can be required for specific indications, like hip fracture, intra-medullary decompression, or other. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  1. Applied hydraulic transients

    CERN Document Server

    Chaudhry, M Hanif

    2014-01-01

    This book covers hydraulic transients in a comprehensive and systematic manner from introduction to advanced level and presents various methods of analysis for computer solution. The field of application of the book is very broad and diverse and covers areas such as hydroelectric projects, pumped storage schemes, water-supply systems, cooling-water systems, oil pipelines and industrial piping systems. Strong emphasis is given to practical applications, including several case studies, problems of applied nature, and design criteria. This will help design engineers and introduce students to real-life projects. This book also: ·         Presents modern methods of analysis suitable for computer analysis, such as the method of characteristics, explicit and implicit finite-difference methods and matrix methods ·         Includes case studies of actual projects ·         Provides extensive and complete treatment of governed hydraulic turbines ·         Presents design charts, desi...

  2. Quantitative phylogenetic assessment of microbial communities indiverse environments

    Energy Technology Data Exchange (ETDEWEB)

    von Mering, C.; Hugenholtz, P.; Raes, J.; Tringe, S.G.; Doerks,T.; Jensen, L.J.; Ward, N.; Bork, P.

    2007-01-01

    The taxonomic composition of environmental communities is an important indicator of their ecology and function. Here, we use a set of protein-coding marker genes, extracted from large-scale environmental shotgun sequencing data, to provide a more direct, quantitative and accurate picture of community composition than traditional rRNA-based approaches using polymerase chain reaction (PCR). By mapping marker genes from four diverse environmental data sets onto a reference species phylogeny, we show that certain communities evolve faster than others, determine preferred habitats for entire microbial clades, and provide evidence that such habitat preferences are often remarkably stable over time.

  3. Toward a microbial Neolithic revolution in buildings.

    Science.gov (United States)

    Thaler, David S

    2016-03-29

    The Neolithic revolution--the transition of our species from hunter and gatherer to cultivator--began approximately 14,000 years ago and is essentially complete for macroscopic food. Humans remain largely pre-Neolithic in our relationship with microbes but starting with the gut we continue our hundred-year project of approaching the ability to assess and cultivate benign microbiomes in our bodies. Buildings are analogous to the body and it is time to ask what it means to cultivate benign microbiomes in our built environment. A critical distinction is that we have not found, or invented, niches in buildings where healthful microbial metabolism occurs and/or could be cultivated. Key events affecting the health and healthfulness of buildings such as a hurricane leading to a flood or a burst pipe occur only rarely and unpredictably. The cause may be transient but the effects can be long lasting and, e.g., for moisture damage, cumulative. Non-invasive "building tomography" could find moisture and "sentinel microbes" could record the integral of transient growth. "Seed" microbes are metabolically inert cells able to grow when conditions allow. All microbes and their residue present actinic molecules including immunological epitopes (molecular shapes). The fascinating hygiene and microbial biodiversity hypotheses propose that a healthy immune system requires exposure to a set of microbial epitopes that is rich in diversity. A particular conjecture is that measures of the richness of diversity derived from microbiome next-generation sequencing (NGS) can be mechanistically coupled to--rather than merely correlated with some measures of--human health. These hypotheses and conjectures inspire workers and funders but an alternative is also consequent to the first Neolithic revolution: That the genetic uniformity of contemporary foods may also decrease human exposure to molecular biodiversity in a heath-relevant manner. Understanding the consequences--including the unintended

  4. Clay Animals and Their Habitats

    Science.gov (United States)

    Adamson, Kay

    2010-01-01

    Creating clay animals and their habitats with second-grade students has long been one of the author's favorite classroom activities. Students love working with clay and they also enjoy drawing animal homes. In this article, the author describes how the students created a diorama instead of drawing their clay animal's habitat. This gave students…

  5. Habitat modeling for biodiversity conservation.

    Science.gov (United States)

    Bruce G. Marcot

    2006-01-01

    Habitat models address only 1 component of biodiversity but can be useful in addressing and managing single or multiple species and ecosystem functions, for projecting disturbance regimes, and in supporting decisions. I review categories and examples of habitat models, their utility for biodiversity conservation, and their roles in making conservation decisions. I...

  6. Habitat specialization through germination cueing

    DEFF Research Database (Denmark)

    Ten Brink, Dirk-Jan; Hendriksma, Harmen; Bruun, Hans Henrik

    2013-01-01

    This study examined the adaptive association between seed germination ecology and specialization to either forest or open habitats across a range of evolutionary lineages of seed plants, in order to test the hypotheses that (1) species' specialization to open vs. shaded habitats is consistently...

  7. Food technology in space habitats

    Science.gov (United States)

    Karel, M.

    1979-01-01

    The research required to develop a system that will provide for acceptable, nutritious, and safe diets for man during extended space missions is discussed. The development of a food technology system for space habitats capable of converting raw materials produced in the space habitats into acceptable food is examined.

  8. Microbial electrosynthetic cells

    Energy Technology Data Exchange (ETDEWEB)

    May, Harold D.; Marshall, Christopher W.; Labelle, Edward V.

    2018-01-30

    Methods are provided for microbial electrosynthesis of H.sub.2 and organic compounds such as methane and acetate. Method of producing mature electrosynthetic microbial populations by continuous culture is also provided. Microbial populations produced in accordance with the embodiments as shown to efficiently synthesize H.sub.2, methane and acetate in the presence of CO.sub.2 and a voltage potential. The production of biodegradable and renewable plastics from electricity and carbon dioxide is also disclosed.

  9. Research and Application of Marine Microbial Enzymes: Status and Prospects

    Science.gov (United States)

    Zhang, Chen; Kim, Se-Kwon

    2010-01-01

    Over billions of years, the ocean has been regarded as the origin of life on Earth. The ocean includes the largest range of habitats, hosting the most life-forms. Competition amongst microorganisms for space and nutrients in the marine environment is a powerful selective force, which has led to evolution. The evolution prompted the marine microorganisms to generate multifarious enzyme systems to adapt to the complicated marine environments. Therefore, marine microbial enzymes can offer novel biocatalysts with extraordinary properties. This review deals with the research and development work investigating the occurrence and bioprocessing of marine microbial enzymes. PMID:20631875

  10. Mars polar cap: a habitat for elementary life1

    Science.gov (United States)

    Wallis, M. K.; Wickramasinghe, N. C.

    2009-04-01

    Ices in the Martian polar caps are potential habitats for various species of microorganisms. Salts in the ice and biological anti-freeze polymers maintain liquid in cracks in the ices far below 0°C, possibly down to the mean 220-240 K. Sub-surface microbial life is shielded from ultraviolet (UV) radiation, but could potentially be activated on south-facing slopes under the midday, midsummer Sun. Such life would be limited by low levels of vapour, little transport of nutrients, low light levels below a protective dirt-crust, frost accumulation at night and in shadows, and little if any active translocation of organisms. As in the Antarctic and in permafrost, movement to new habitats depends on geo-climatic changes, which for Mars's north polar cap occur on a 50 000 year scale, except for rare meteorite impacts.

  11. Explosive and radio-selected Transients: Transient Astronomy with ...

    Indian Academy of Sciences (India)

    40

    sitive measurements will lead to very accurate mass loss estimation in these supernovae. .... transients are powerful probes of intervening media owing to dispersion ...... A., & Chandra, P. 2011, Nature Communications,. 2, 175. Chakraborti, S.

  12. Habitats and Species Covered by the EEC Habitats Directive

    DEFF Research Database (Denmark)

    Pihl, S.; Søgaard, B.; Ejrnæs, R.

    of Conservation (SAC's), Natura 2000. The designations are based upon the presence of 60 of the natural habitat types listed in Annex I of the Directive and approx. 44 of the species listed in Annex II which occur within the territory of Denmark and for the conservation of which the Community has a special...... and the Danish county authorities have initiated a co-operative programme to provide and compile the data necessary to assess the conservation status of the natural habitat types and species concerned. The purpose of this report is to present the conservation status of the habitats and species in Denmark...

  13. Analyses of the microbial diversity across the human microbiome.

    Directory of Open Access Journals (Sweden)

    Kelvin Li

    Full Text Available Analysis of human body microbial diversity is fundamental to understanding community structure, biology and ecology. The National Institutes of Health Human Microbiome Project (HMP has provided an unprecedented opportunity to examine microbial diversity within and across body habitats and individuals through pyrosequencing-based profiling of 16 S rRNA gene sequences (16 S from habits of the oral, skin, distal gut, and vaginal body regions from over 200 healthy individuals enabling the application of statistical techniques. In this study, two approaches were applied to elucidate the nature and extent of human microbiome diversity. First, bootstrap and parametric curve fitting techniques were evaluated to estimate the maximum number of unique taxa, S(max, and taxa discovery rate for habitats across individuals. Next, our results demonstrated that the variation of diversity within low abundant taxa across habitats and individuals was not sufficiently quantified with standard ecological diversity indices. This impact from low abundant taxa motivated us to introduce a novel rank-based diversity measure, the Tail statistic, ("τ", based on the standard deviation of the rank abundance curve if made symmetric by reflection around the most abundant taxon. Due to τ's greater sensitivity to low abundant taxa, its application to diversity estimation of taxonomic units using taxonomic dependent and independent methods revealed a greater range of values recovered between individuals versus body habitats, and different patterns of diversity within habitats. The greatest range of τ values within and across individuals was found in stool, which also exhibited the most undiscovered taxa. Oral and skin habitats revealed variable diversity patterns, while vaginal habitats were consistently the least diverse. Collectively, these results demonstrate the importance, and motivate the introduction, of several visualization and analysis methods tuned specifically for

  14. Transient-Switch-Signal Suppressor

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1995-01-01

    Circuit delays transmission of switch-opening or switch-closing signal until after preset suppression time. Used to prevent transmission of undesired momentary switch signal. Basic mode of operation simple. Beginning of switch signal initiates timing sequence. If switch signal persists after preset suppression time, circuit transmits switch signal to external circuitry. If switch signal no longer present after suppression time, switch signal deemed transient, and circuit does not pass signal on to external circuitry, as though no transient switch signal. Suppression time preset at value large enough to allow for damping of underlying pressure wave or other mechanical transient.

  15. Electromagnetic transients in power cables

    CERN Document Server

    da Silva, Filipe Faria

    2013-01-01

    From the more basic concepts to the most advanced ones where long and laborious simulation models are required, Electromagnetic Transients in Power Cables provides a thorough insight into the study of electromagnetic transients and underground power cables. Explanations and demonstrations of different electromagnetic transient phenomena are provided, from simple lumped-parameter circuits to complex cable-based high voltage networks, as well as instructions on how to model the cables.Supported throughout by illustrations, circuit diagrams and simulation results, each chapter contains exercises,

  16. Microbial community dynamics and transformation of vascular plant detritus in two wetland ecosystems

    International Nuclear Information System (INIS)

    Moran, M.A.

    1987-01-01

    The microbial ecology of two wetland ecosystems in southeastern Georgia, USA, was studied with respect to microbial community dynamics and microbially-mediated transformations of vascular plant detritus. In the Okefenokee Swamp, biomass of microorganisms in the water column and sediments was generally lower in winter months and higher during spring and summer. Biomass and activity (measured as 14 C-lignocellulose mineralization) differed significantly among five habitats within the Okefenokee, and also among locations within each habitat. Significant heterogeneity in the structure of Okefenokee microbial communities was found at scales from 30 cm to 150 m. In field and laboratory studies of vascular plant decomposition in the Okefenokee and a salt marsh on Sapelo Island, the mathematical model which best describes decomposition kinetics is the decaying coefficient model

  17. Habitat Predicts Levels of Genetic Admixture in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Viranga Tilakaratna

    2017-09-01

    Full Text Available Genetic admixture can provide material for populations to adapt to local environments, and this process has played a crucial role in the domestication of plants and animals. The model yeast, Saccharomyces cerevisiae, has been domesticated multiple times for the production of wine, sake, beer, and bread, but the high rate of admixture between yeast lineages has so far been treated as a complication for population genomic analysis. Here, we make use of the low recombination rate at centromeres to investigate admixture in yeast using a classic Bayesian approach and a locus-by-locus phylogenetic approach. Using both approaches, we find that S. cerevisiae from stable oak woodland habitats are less likely to show recent genetic admixture compared with those isolated from transient habitats such as fruits, wine, or human infections. When woodland yeast strains do show recent genetic admixture, the degree of admixture is lower than in strains from other habitats. Furthermore, S. cerevisiae populations from oak woodlands are genetically isolated from each other, with only occasional migration between woodlands and local fruit habitats. Application of the phylogenetic approach suggests that there is a previously undetected population in North Africa that is the closest outgroup to the European S. cerevisiae, including the domesticated Wine population. Careful testing for admixture in S. cerevisiae leads to a better understanding of the underlying population structure of the species and will be important for understanding the selective processes underlying domestication in this economically important species.

  18. Habitat Predicts Levels of Genetic Admixture in Saccharomyces cerevisiae.

    Science.gov (United States)

    Tilakaratna, Viranga; Bensasson, Douda

    2017-09-07

    Genetic admixture can provide material for populations to adapt to local environments, and this process has played a crucial role in the domestication of plants and animals. The model yeast, Saccharomyces cerevisiae , has been domesticated multiple times for the production of wine, sake, beer, and bread, but the high rate of admixture between yeast lineages has so far been treated as a complication for population genomic analysis. Here, we make use of the low recombination rate at centromeres to investigate admixture in yeast using a classic Bayesian approach and a locus-by-locus phylogenetic approach. Using both approaches, we find that S. cerevisiae from stable oak woodland habitats are less likely to show recent genetic admixture compared with those isolated from transient habitats such as fruits, wine, or human infections. When woodland yeast strains do show recent genetic admixture, the degree of admixture is lower than in strains from other habitats. Furthermore, S. cerevisiae populations from oak woodlands are genetically isolated from each other, with only occasional migration between woodlands and local fruit habitats. Application of the phylogenetic approach suggests that there is a previously undetected population in North Africa that is the closest outgroup to the European S. cerevisiae , including the domesticated Wine population. Careful testing for admixture in S. cerevisiae leads to a better understanding of the underlying population structure of the species and will be important for understanding the selective processes underlying domestication in this economically important species. Copyright © 2017 Tilakaratna and Bensasson.

  19. Feedbacks Between Soil Structure and Microbial Activities in Soil

    Science.gov (United States)

    Bailey, V. L.; Smith, A. P.; Fansler, S.; Varga, T.; Kemner, K. M.; McCue, L. A.

    2017-12-01

    Soil structure provides the physical framework for soil microbial habitats. The connectivity and size distribution of soil pores controls the microbial access to nutrient resources for growth and metabolism. Thus, a crucial component of soil research is how a soil's three-dimensional structure and organization influences its biological potential on a multitude of spatial and temporal scales. In an effort to understand microbial processes at scale more consistent with a microbial community, we have used soil aggregates as discrete units of soil microbial habitats. Our research has shown that mean pore diameter (x-ray computed tomography) of soil aggregates varies with the aggregate diameter itself. Analyzing both the bacterial composition (16S) and enzyme activities of individual aggregates showed significant differences in the relative abundances of key members the microbial communities associated with high enzyme activities compared to those with low activities, even though we observed no differences in the size of the biomass, nor in the overall richness or diversity of these communities. We hypothesize that resources and substrates have stimulated key populations in the aggregates identified as highly active, and as such, we conducted further research that explored how such key populations (i.e. fungal or bacterial dominated populations) alter pathways of C accumulation in aggregate size domains and microbial C utilization. Fungi support and stabilize soil structure through both physical and chemical effects of their hyphal networks. In contrast, bacterial-dominated communities are purported to facilitate micro- and fine aggregate stabilization. Here we quantify the direct effects fungal versus bacterial dominated communities on aggregate formation (both the rate of aggregation and the quality, quantity and distribution of SOC contained within aggregates). A quantitative understanding of the different mechanisms through which fungi or bacteria shape aggregate

  20. Coupling Spatiotemporal Community Assembly Processes to Changes in Microbial Metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Graham, Emily B.; Crump, Alex R.; Resch, Charles T.; Fansler, Sarah; Arntzen, Evan; Kennedy, David W.; Fredrickson, Jim K.; Stegen, James C.

    2016-12-16

    Community assembly processes govern shifts in species abundances in response to environmental change, yet our understanding of assembly remains largely decoupled from ecosystem function. Here, we test hypotheses regarding assembly and function across space and time using hyporheic microbial communities as a model system. We pair sampling of two habitat types through hydrologic fluctuation with null modeling and multivariate statistics. We demonstrate that dual selective pressures assimilate to generate compositional changes at distinct timescales among habitat types, resulting in contrasting associations of Betaproteobacteria and Thaumarchaeota with selection and with seasonal changes in aerobic metabolism. Our results culminate in a conceptual model in which selection from contrasting environments regulates taxon abundance and ecosystem function through time, with increases in function when oscillating selection opposes stable selective pressures. Our model is applicable within both macrobial and microbial ecology and presents an avenue for assimilating community assembly processes into predictions of ecosystem function.

  1. Steelhead Critical Habitat, Coast - NOAA [ds122

    Data.gov (United States)

    California Department of Resources — This layer depicts areas designated for Steelhead Critical Habitat as well as habitat type and quality in the Coastal California Steelhead ESUs (evolutionarily...

  2. Transient or permanent fisheye views

    DEFF Research Database (Denmark)

    Jakobsen, Mikkel Rønne; Hornbæk, Kasper

    2012-01-01

    Transient use of information visualization may support specific tasks without permanently changing the user interface. Transient visualizations provide immediate and transient use of information visualization close to and in the context of the user’s focus of attention. Little is known, however......, about the benefits and limitations of transient visualizations. We describe an experiment that compares the usability of a fisheye view that participants could call up temporarily, a permanent fisheye view, and a linear view: all interfaces gave access to source code in the editor of a widespread...... programming environment. Fourteen participants performed varied tasks involving navigation and understanding of source code. Participants used the three interfaces for between four and six hours in all. Time and accuracy measures were inconclusive, but subjective data showed a preference for the permanent...

  3. Transient thyrotoxicosis during nivolumab treatment

    NARCIS (Netherlands)

    van Kooten, M. J.; van den Berg, G.; Glaudemans, A. W. J. M.; Hiltermann, T. J. N.; Groen, H. J. M.; Rutgers, A.; Links, T. P.

    Two patients presented with transient thyrotoxicosis within 2-4 weeks after starting treatment with nivolumab. This thyrotoxicosis turned into hypothyroidism within 6-8 weeks. Temporary treatment with a beta blocker may be sufficient.

  4. Spatial Distribution of Viruses Associated with Planktonic and Attached Microbial Communities in Hydrothermal Environments

    Science.gov (United States)

    Nunoura, Takuro; Kazama, Hiromi; Noguchi, Takuroh; Inoue, Kazuhiro; Akashi, Hironori; Yamanaka, Toshiro; Toki, Tomohiro; Yamamoto, Masahiro; Furushima, Yasuo; Ueno, Yuichiro; Yamamoto, Hiroyuki; Takai, Ken

    2012-01-01

    Viruses play important roles in marine surface ecosystems, but little is known about viral ecology and virus-mediated processes in deep-sea hydrothermal microbial communities. In this study, we examined virus-like particle (VLP) abundances in planktonic and attached microbial communities, which occur in physical and chemical gradients in both deep and shallow submarine hydrothermal environments (mixing waters between hydrothermal fluids and ambient seawater and dense microbial communities attached to chimney surface areas or macrofaunal bodies and colonies). We found that viruses were widely distributed in a variety of hydrothermal microbial habitats, with the exception of the interior parts of hydrothermal chimney structures. The VLP abundance and VLP-to-prokaryote ratio (VPR) in the planktonic habitats increased as the ratio of hydrothermal fluid to mixing water increased. On the other hand, the VLP abundance in attached microbial communities was significantly and positively correlated with the whole prokaryotic abundance; however, the VPRs were always much lower than those for the surrounding hydrothermal waters. This is the first report to show VLP abundance in the attached microbial communities of submarine hydrothermal environments, which presented VPR values significantly lower than those in planktonic microbial communities reported before. These results suggested that viral lifestyles (e.g., lysogenic prevalence) and virus interactions with prokaryotes are significantly different among the planktonic and attached microbial communities that are developing in the submarine hydrothermal environments. PMID:22210205

  5. Riparian Habitat - Product of 2 riparian habitat workshops

    Data.gov (United States)

    California Natural Resource Agency — In two riparian habitat workshops held between 2001 and 2002, scientists and managers identified the need for determining the scope of a consistent and acceptable...

  6. Microbial accumulation of uranium

    International Nuclear Information System (INIS)

    Zhang Wei; Dong Faqin; Dai Qunwei

    2005-01-01

    The mechanism of microbial accumulation of uranium and the effects of some factors (including pH, initial uranium concentration, pretreatment of bacteria, and so on) on microbial accumulation of uranium are discussed briefly. The research direction and application prospect are presented. (authors)

  7. MICROBIAL FUEL CELL

    DEFF Research Database (Denmark)

    2008-01-01

    A novel microbial fuel cell construction for the generation of electrical energy. The microbial fuel cell comprises: (i) an anode electrode, (ii) a cathode chamber, said cathode chamber comprising an in let through which an influent enters the cathode chamber, an outlet through which an effluent...

  8. Microbial control of pollution

    Energy Technology Data Exchange (ETDEWEB)

    Fry, J C; Gadd, G M; Herbert, R A; Jones, C W; Watson-Craik, I A [eds.

    1992-01-01

    12 papers are presented on the microbial control of pollution. Topics covered include: bioremediation of oil spills; microbial control of heavy metal pollution; pollution control using microorganisms and magnetic separation; degradation of cyanide and nitriles; nitrogen removal from water and waste; and land reclamation and restoration.

  9. Transient Tsunamis in Lakes

    Science.gov (United States)

    Couston, L.; Mei, C.; Alam, M.

    2013-12-01

    A large number of lakes are surrounded by steep and unstable mountains with slopes prone to failure. As a result, landslides are likely to occur and impact water sitting in closed reservoirs. These rare geological phenomena pose serious threats to dam reservoirs and nearshore facilities because they can generate unexpectedly large tsunami waves. In fact, the tallest wave experienced by contemporary humans occurred because of a landslide in the narrow bay of Lituya in 1958, and five years later, a deadly landslide tsunami overtopped Lake Vajont's dam, flooding and damaging villages along the lakefront and in the Piave valley. If unstable slopes and potential slides are detected ahead of time, inundation maps can be drawn to help people know the risks, and mitigate the destructive power of the ensuing waves. These maps give the maximum wave runup height along the lake's vertical and sloping boundaries, and can be obtained by numerical simulations. Keeping track of the moving shorelines along beaches is challenging in classical Eulerian formulations because the horizontal extent of the fluid domain can change over time. As a result, assuming a solid slide and nonbreaking waves, here we develop a nonlinear shallow-water model equation in the Lagrangian framework to address the problem of transient landslide-tsunamis. In this manner, the shorelines' three-dimensional motion is part of the solution. The model equation is hyperbolic and can be solved numerically by finite differences. Here, a 4th order Runge-Kutta method and a compact finite-difference scheme are implemented to integrate in time and spatially discretize the forced shallow-water equation in Lagrangian coordinates. The formulation is applied to different lake and slide geometries to better understand the effects of the lake's finite lengths and slide's forcing mechanism on the generated wavefield. Specifically, for a slide moving down a plane beach, we show that edge-waves trapped by the shoreline and free

  10. Transient two-phase flow

    International Nuclear Information System (INIS)

    Hsu, Y.Y.

    1974-01-01

    The following papers related to two-phase flow are summarized: current assumptions made in two-phase flow modeling; two-phase unsteady blowdown from pipes, flow pattern in Laval nozzle and two-phase flow dynamics; dependence of radial heat and momentum diffusion; transient behavior of the liquid film around the expanding gas slug in a vertical tube; flooding phenomena in BWR fuel bundles; and transient effects in bubble two-phase flow. (U.S.)

  11. Protection of Antarctic microbial communities – ‘out of sight, out of mind’

    Science.gov (United States)

    Hughes, Kevin A.; Cowan, Don A.; Wilmotte, Annick

    2015-01-01

    Recent advances in molecular biology techniques have shown the presence of diverse microbial communities and endemic species in Antarctica. Endemic microbes may be a potential source of novel biotechnologically important compounds, including, for example, new antibiotics. Thus, the scientific and biotechnological value of Antarctic terrestrial microbial habitats can be compromised by human visitation to a greater extent than previously realized. The ever-increasing human footprint in Antarctica makes consideration of this topic more pressing, as the number of locations known to be pristine habitats, where increasingly sophisticated cutting-edge research techniques may be used to their full potential, declines. Examination of the Protected Areas system of the Antarctic Treaty shows that microbial habitats are generally poorly protected. No other continent on Earth is dominated to the same degree by microbial species, and real opportunities exist to develop new ways of conceptualizing and implementing conservation of microbial biogeography on a continental scale. Here we highlight potential threats both to the conservation of terrestrial microbial ecosystems, and to future scientific research requiring their study. PMID:25762992

  12. Riparian Habitat - San Joaquin River

    Data.gov (United States)

    California Natural Resource Agency — The immediate focus of this study is to identify, describe and map the extent and diversity of riparian habitats found along the main stem of the San Joaquin River,...

  13. Tidal Creek Sentinel Habitat Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Ecological Research, Assessment and Prediction's Tidal Creeks: Sentinel Habitat Database was developed to support the National Oceanic and Atmospheric...

  14. Deep Space Habitat Concept Demonstrator

    Science.gov (United States)

    Bookout, Paul S.; Smitherman, David

    2015-01-01

    This project will develop, integrate, test, and evaluate Habitation Systems that will be utilized as technology testbeds and will advance NASA's understanding of alternative deep space mission architectures, requirements, and operations concepts. Rapid prototyping and existing hardware will be utilized to develop full-scale habitat demonstrators. FY 2014 focused on the development of a large volume Space Launch System (SLS) class habitat (Skylab Gen 2) based on the SLS hydrogen tank components. Similar to the original Skylab, a tank section of the SLS rocket can be outfitted with a deep space habitat configuration and launched as a payload on an SLS rocket. This concept can be used to support extended stay at the Lunar Distant Retrograde Orbit to support the Asteroid Retrieval Mission and provide a habitat suitable for human missions to Mars.

  15. Leatherback Sea Turtle Critical Habitat

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data represent the critical habitat for leatherback turtle as designated by Federal Register Vol. 44, No. 17711, March 23, 1979, Rules and Regulations....

  16. Hawksbill Sea Turtle Critical Habitat

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data represent the critical habitat for hawksbill turtle as designated by Federal Register Vol. 63, No. 46701, September 2, 1998, Rules and Regulations....

  17. Endangered Species Act Critical Habitat

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Critical habitat (CH) is designated for the survival and recovery of species listed as threatened or endangered under the Endangered Species Act (ESA). Critical...

  18. Transient magnetoviscosity of dilute ferrofluids

    International Nuclear Information System (INIS)

    Soto-Aquino, Denisse; Rinaldi, Carlos

    2011-01-01

    The magnetic field induced change in the viscosity of a ferrofluid, commonly known as the magnetoviscous effect and parameterized through the magnetoviscosity, is one of the most interesting and practically relevant aspects of ferrofluid phenomena. Although the steady state behavior of ferrofluids under conditions of applied constant magnetic fields has received considerable attention, comparatively little attention has been given to the transient response of the magnetoviscosity to changes in the applied magnetic field or rate of shear deformation. Such transient response can provide further insight into the dynamics of ferrofluids and find practical application in the design of devices that take advantage of the magnetoviscous effect and inevitably must deal with changes in the applied magnetic field and deformation. In this contribution Brownian dynamics simulations and a simple model based on the ferrohydrodynamics equations are applied to explore the dependence of the transient magnetoviscosity for two cases: (I) a ferrofluid in a constant shear flow wherein the magnetic field is suddenly turned on, and (II) a ferrofluid in a constant magnetic field wherein the shear flow is suddenly started. Both simulations and analysis show that the transient approach to a steady state magnetoviscosity can be either monotonic or oscillatory depending on the relative magnitudes of the applied magnetic field and shear rate. - Research Highlights: →Rotational Brownian dynamics simulations were used to study the transient behavior of the magnetoviscosity of ferrofluids. →Damped and oscillatory approach to steady state magnetoviscosity was observed for step changes in shear rate and magnetic field. →A model based on the ferrohydrodynamics equations qualitatively captured the damped and oscillatory features of the transient response →The transient behavior is due to the interplay of hydrodynamic, magnetic, and Brownian torques on the suspended particles.

  19. Biogeography of serpentinite-hosted microbial ecosystems

    Science.gov (United States)

    Brazelton, W.; Cardace, D.; Fruh-Green, G.; Lang, S. Q.; Lilley, M. D.; Morrill, P. L.; Szponar, N.; Twing, K. I.; Schrenk, M. O.

    2012-12-01

    Ultramafic rocks in the Earth's mantle represent a tremendous reservoir of carbon and reducing power. Upon tectonic uplift and exposure to fluid flow, serpentinization of these materials generates copious energy, sustains abiogenic synthesis of organic molecules, and releases hydrogen gas (H2). To date, however, the "serpentinite microbiome" is poorly constrained- almost nothing is known about the microbial diversity endemic to rocks actively undergoing serpentinization. Through the Census of Deep Life, we have obtained 16S rRNA gene pyrotag sequences from fluids and rocks from serpentinizing ophiolites in California, Canada, and Italy. The samples include high pH serpentinite springs, presumably representative of deeper environments within the ophiolite complex, wells which directly access subsurface aquifers, and rocks obtained from drill cores into serpentinites. These data represent a unique opportunity to examine biogeographic patterns among a restricted set of microbial taxa that are adapted to similar environmental conditions and are inhabiting sites with related geological histories. In general, our results point to potentially H2-utilizing Betaproteobacteria thriving in shallow, oxic-anoxic transition zones and anaerobic Clostridia thriving in anoxic, deep subsurface habitats. These general taxonomic and biogeochemical trends were also observed in seafloor Lost City hydrothermal chimneys, indicating that we are beginning to identify a core serpentinite microbial community that spans marine and continental settings.

  20. Gammarus-Microbial Interactions: A Review

    Directory of Open Access Journals (Sweden)

    Daniel Nelson

    2011-01-01

    Full Text Available Gammarus spp. are typically classified as shredders under the functional feeding group classification. In the wild and in the laboratory, Gammarus spp. will often shred leaves, breaking them down into finer organic matter fractions. However, leaf litter is a poor quality food source (i.e., high C : N and C : P ratios and very little leaf material is assimilated by shredders. In freshwater habitats leaf litter is colonized rapidly (within ∼1-2 weeks by aquatic fungi and bacteria, making the leaves more palatable and nutritious to consumers. Several studies have shown that Gammarus spp. show preference for conditioned leaves over nonconditioned leaves and certain fungal species to others. Furthermore, Gammarus spp. show increased survival and growth rates when fed conditioned leaves compared to non-conditioned leaves. Thus, Gammarus spp. appear to rely on the microbial biofilm associated with leaf detritus as a source of carbon and/or essential nutrients. Also, Gammarus spp. can have both positive and negative effects on the microbial communities on which they fed, making them an important component of the microbial loop in aquatic ecosystems.

  1. Requirements for modeling airborne microbial contamination in space stations

    Science.gov (United States)

    Van Houdt, Rob; Kokkonen, Eero; Lehtimäki, Matti; Pasanen, Pertti; Leys, Natalie; Kulmala, Ilpo

    2018-03-01

    Exposure to bioaerosols is one of the facets that affect indoor air quality, especially for people living in densely populated or confined habitats, and is associated to a wide range of health effects. Good indoor air quality is thus vital and a prerequisite for fully confined environments such as space habitats. Bioaerosols and microbial contamination in these confined space stations can have significant health impacts, considering the unique prevailing conditions and constraints of such habitats. Therefore, biocontamination in space stations is strictly monitored and controlled to ensure crew and mission safety. However, efficient bioaerosol control measures rely on solid understanding and knowledge on how these bioaerosols are created and dispersed, and which factors affect the survivability of the associated microorganisms. Here we review the current knowledge gained from relevant studies in this wide and multidisciplinary area of bioaerosol dispersion modeling and biological indoor air quality control, specifically taking into account the specific space conditions.

  2. Microbial activity in the marine deep biosphere: Progress and prospects

    Directory of Open Access Journals (Sweden)

    Beth N Orcutt

    2013-07-01

    Full Text Available The vast marine deep biosphere consists of microbial habitats within sediment, pore waters, upper basaltic crust and the fluids that circulate throughout it. A wide range of temperature, pressure, pH, and electron donor and acceptor conditions exists – all of which can combine to affect carbon and nutrient cycling and result in gradients on spatial scales ranging from millimeters to kilometers. Diverse and mostly uncharacterized microorganisms live in these habitats, and potentially play a role in mediating global scale biogeochemical processes. Quantifying the rates at which microbial activity in the subsurface occurs is a challenging endeavor, yet developing an understanding of these rates is essential to determine the impact of subsurface life on Earth's global biogeochemical cycles, and for understanding how microorganisms in these "extreme" environments survive (or even thrive. Here, we synthesize recent advances and discoveries pertaining to microbial activity in the marine deep subsurface, and we highlight topics about which there is still little understanding and suggest potential paths forward to address them. This publication is the result of a workshop held in August 2012 by the NSF-funded Center for Dark Energy Biosphere Investigations (C-DEBI "theme team" on microbial activity (www.darkenergybiosphere.org.

  3. Microbial activity in the marine deep biosphere: progress and prospects

    Science.gov (United States)

    Orcutt, Beth N.; LaRowe, Douglas E.; Biddle, Jennifer F.; Colwell, Frederick S.; Glazer, Brian T.; Reese, Brandi Kiel; Kirkpatrick, John B.; Lapham, Laura L.; Mills, Heath J.; Sylvan, Jason B.; Wankel, Scott D.; Wheat, C. Geoff

    2013-01-01

    The vast marine deep biosphere consists of microbial habitats within sediment, pore waters, upper basaltic crust and the fluids that circulate throughout it. A wide range of temperature, pressure, pH, and electron donor and acceptor conditions exists—all of which can combine to affect carbon and nutrient cycling and result in gradients on spatial scales ranging from millimeters to kilometers. Diverse and mostly uncharacterized microorganisms live in these habitats, and potentially play a role in mediating global scale biogeochemical processes. Quantifying the rates at which microbial activity in the subsurface occurs is a challenging endeavor, yet developing an understanding of these rates is essential to determine the impact of subsurface life on Earth's global biogeochemical cycles, and for understanding how microorganisms in these “extreme” environments survive (or even thrive). Here, we synthesize recent advances and discoveries pertaining to microbial activity in the marine deep subsurface, and we highlight topics about which there is still little understanding and suggest potential paths forward to address them. This publication is the result of a workshop held in August 2012 by the NSF-funded Center for Dark Energy Biosphere Investigations (C-DEBI) “theme team” on microbial activity (www.darkenergybiosphere.org). PMID:23874326

  4. Microbial activity in the marine deep biosphere: progress and prospects.

    Science.gov (United States)

    Orcutt, Beth N; Larowe, Douglas E; Biddle, Jennifer F; Colwell, Frederick S; Glazer, Brian T; Reese, Brandi Kiel; Kirkpatrick, John B; Lapham, Laura L; Mills, Heath J; Sylvan, Jason B; Wankel, Scott D; Wheat, C Geoff

    2013-01-01

    The vast marine deep biosphere consists of microbial habitats within sediment, pore waters, upper basaltic crust and the fluids that circulate throughout it. A wide range of temperature, pressure, pH, and electron donor and acceptor conditions exists-all of which can combine to affect carbon and nutrient cycling and result in gradients on spatial scales ranging from millimeters to kilometers. Diverse and mostly uncharacterized microorganisms live in these habitats, and potentially play a role in mediating global scale biogeochemical processes. Quantifying the rates at which microbial activity in the subsurface occurs is a challenging endeavor, yet developing an understanding of these rates is essential to determine the impact of subsurface life on Earth's global biogeochemical cycles, and for understanding how microorganisms in these "extreme" environments survive (or even thrive). Here, we synthesize recent advances and discoveries pertaining to microbial activity in the marine deep subsurface, and we highlight topics about which there is still little understanding and suggest potential paths forward to address them. This publication is the result of a workshop held in August 2012 by the NSF-funded Center for Dark Energy Biosphere Investigations (C-DEBI) "theme team" on microbial activity (www.darkenergybiosphere.org).

  5. Microbial community assembly and metabolic function during mammalian corpse decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Metcalf, J. L.; Xu, Z. Z.; Weiss, S.; Lax, S.; Van Treuren, W.; Hyde, E. R.; Song, S. J.; Amir, A.; Larsen, P.; Sangwan, N.; Haarmann, D.; Humphrey, G. C.; Ackermann, G.; Thompson, L. R.; Lauber, C.; Bibat, A.; Nicholas, C.; Gebert, M. J.; Petrosino, J. F.; Reed, S. C.; Gilbert, J. A.; Lynne, A. M.; Bucheli, S. R.; Carter, D. O.; Knight, R.

    2015-12-10

    Vertebrate corpse decomposition provides an important stage in nutrient cycling in most terrestrial habitats, yet microbially mediated processes are poorly understood. Here we combine deep microbial community characterization, community-level metabolic reconstruction, and soil biogeochemical assessment to understand the principles governing microbial community assembly during decomposition of mouse and human corpses on different soil substrates. We find a suite of bacterial and fungal groups that contribute to nitrogen cycling and a reproducible network of decomposers that emerge on predictable time scales. Our results show that this decomposer community is derived primarily from bulk soil, but key decomposers are ubiquitous in low abundance. Soil type was not a dominant factor driving community development, and the process of decomposition is sufficiently reproducible to offer new opportunities for forensic investigations.

  6. Microbial ecology of deep-water mid-Atlantic canyons

    Science.gov (United States)

    Kellogg, Christina A.

    2011-01-01

    The research described in this fact sheet will be conducted from 2012 to 2014 as part of the U.S. Geological Survey's DISCOVRE (DIversity, Systematics, and COnnectivity of Vulnerable Reef Ecosystems) Program. This integrated, multidisciplinary effort will be investigating a variety of topics related to unique and fragile deep-sea ecosystems from the microscopic level to the ecosystem level. One goal is to improve understanding, at the microbiological scale, of the benthic communities (including corals) that reside in and around mid-Atlantic canyon habitats and their associated environments. Specific objectives include identifying and characterizing the microbial associates of deep-sea corals, characterizing the microbial biofilms on hard substrates to better determine their role in engineering the ecosystem, and adding a microbial dimension to benthic community structure and function assessments by characterizing micro-eukaryotes, bacteria, and archaea in deep-sea sediments.

  7. Microbial community assembly and metabolic function during mammalian corpse decomposition

    Science.gov (United States)

    Metcalf, Jessica L; Xu, Zhenjiang Zech; Weiss, Sophie; Lax, Simon; Van Treuren, Will; Hyde, Embriette R.; Song, Se Jin; Amir, Amnon; Larsen, Peter; Sangwan, Naseer; Haarmann, Daniel; Humphrey, Greg C; Ackermann, Gail; Thompson, Luke R; Lauber, Christian; Bibat, Alexander; Nicholas, Catherine; Gebert, Matthew J; Petrosino, Joseph F; Reed, Sasha C.; Gilbert, Jack A; Lynne, Aaron M; Bucheli, Sibyl R; Carter, David O; Knight, Rob

    2016-01-01

    Vertebrate corpse decomposition provides an important stage in nutrient cycling in most terrestrial habitats, yet microbially mediated processes are poorly understood. Here we combine deep microbial community characterization, community-level metabolic reconstruction, and soil biogeochemical assessment to understand the principles governing microbial community assembly during decomposition of mouse and human corpses on different soil substrates. We find a suite of bacterial and fungal groups that contribute to nitrogen cycling and a reproducible network of decomposers that emerge on predictable time scales. Our results show that this decomposer community is derived primarily from bulk soil, but key decomposers are ubiquitous in low abundance. Soil type was not a dominant factor driving community development, and the process of decomposition is sufficiently reproducible to offer new opportunities for forensic investigations.

  8. New England wildlife: management forested habitats

    Science.gov (United States)

    Richard M. DeGraaf; Mariko Yamasaki; William B. Leak; John W. Lanier

    1992-01-01

    Presents silvicultural treatments for six major cover-type groups in New England to produce stand conditions that provide habitat opportunities for a wide range of wildlife species. Includes matrices for species occurrence and utilization by forested and nonforested habitats, habitat breadth and size class, and structural habitat features for the 338 wildlife species...

  9. Pressure transients across HEPA filters

    International Nuclear Information System (INIS)

    Gregory, W.; Reynolds, G.; Ricketts, C.; Smith, P.R.

    1977-01-01

    Nuclear fuel cycle facilities require ventilation for health and safety reasons. High efficiency particulate air (HEPA) filters are located within ventilation systems to trap radioactive dust released in reprocessing and fabrication operations. Pressure transients within the air cleaning systems may be such that the effectiveness of the filtration system is questioned under certain accident conditions. These pressure transients can result from both natural and man-caused phenomena: atmospheric pressure drop caused by a tornado or explosions and nuclear excursions initiate pressure pulses that could create undesirable conditions across HEPA filters. Tornado depressurization is a relatively slow transient as compared to pressure pulses that result from combustible hydrogen-air mixtures. Experimental investigation of these pressure transients across air cleaning equipment has been undertaken by Los Alamos Scientific Laboratory and New Mexico State University. An experimental apparatus has been constructed to impose pressure pulses across HEPA filters. The experimental equipment is described as well as preliminary results using variable pressurization rates. Two modes of filtration of an aerosol injected upstream of the filter is examined. A laser instrumentation for measuring the aerosol release, during the transient, is described

  10. Recent development of transient electronics

    Directory of Open Access Journals (Sweden)

    Huanyu Cheng

    2016-01-01

    Full Text Available Transient electronics are an emerging class of electronics with the unique characteristic to completely dissolve within a programmed period of time. Since no harmful byproducts are released, these electronics can be used in the human body as a diagnostic tool, for instance, or they can be used as environmentally friendly alternatives to existing electronics which disintegrate when exposed to water. Thus, the most crucial aspect of transient electronics is their ability to disintegrate in a practical manner and a review of the literature on this topic is essential for understanding the current capabilities of transient electronics and areas of future research. In the past, only partial dissolution of transient electronics was possible, however, total dissolution has been achieved with a recent discovery that silicon nanomembrane undergoes hydrolysis. The use of single- and multi-layered structures has also been explored as a way to extend the lifetime of the electronics. Analytical models have been developed to study the dissolution of various functional materials as well as the devices constructed from this set of functional materials and these models prove to be useful in the design of the transient electronics.

  11. Wide Field Radio Transient Surveys

    Science.gov (United States)

    Bower, Geoffrey

    2011-04-01

    The time domain of the radio wavelength sky has been only sparsely explored. Nevertheless, serendipitous discovery and results from limited surveys indicate that there is much to be found on timescales from nanoseconds to years and at wavelengths from meters to millimeters. These observations have revealed unexpected phenomena such as rotating radio transients and coherent pulses from brown dwarfs. Additionally, archival studies have revealed an unknown class of radio transients without radio, optical, or high-energy hosts. The new generation of centimeter-wave radio telescopes such as the Allen Telescope Array (ATA) will exploit wide fields of view and flexible digital signal processing to systematically explore radio transient parameter space, as well as lay the scientific and technical foundation for the Square Kilometer Array. Known unknowns that will be the target of future transient surveys include orphan gamma-ray burst afterglows, radio supernovae, tidally-disrupted stars, flare stars, and magnetars. While probing the variable sky, these surveys will also provide unprecedented information on the static radio sky. I will present results from three large ATA surveys (the Fly's Eye survey, the ATA Twenty CM Survey (ATATS), and the Pi GHz Survey (PiGSS)) and several small ATA transient searches. Finally, I will discuss the landscape and opportunities for future instruments at centimeter wavelengths.

  12. Chernobyl reactor transient simulation study

    International Nuclear Information System (INIS)

    Gaber, F.A.; El Messiry, A.M.

    1988-01-01

    This paper deals with the Chernobyl nuclear power station transient simulation study. The Chernobyl (RBMK) reactor is a graphite moderated pressure tube type reactor. It is cooled by circulating light water that boils in the upper parts of vertical pressure tubes to produce steam. At equilibrium fuel irradiation, the RBMK reactor has a positive void reactivity coefficient. However, the fuel temperature coefficient is negative and the net effect of a power change depends upon the power level. Under normal operating conditions the net effect (power coefficient) is negative at full power and becomes positive under certain transient conditions. A series of dynamic performance transient analysis for RBMK reactor, pressurized water reactor (PWR) and fast breeder reactor (FBR) have been performed using digital simulator codes, the purpose of this transient study is to show that an accident of Chernobyl's severity does not occur in PWR or FBR nuclear power reactors. This appears from the study of the inherent, stability of RBMK, PWR and FBR under certain transient conditions. This inherent stability is related to the effect of the feed back reactivity. The power distribution stability in the graphite RBMK reactor is difficult to maintain throughout its entire life, so the reactor has an inherent instability. PWR has larger negative temperature coefficient of reactivity, therefore, the PWR by itself has a large amount of natural stability, so PWR is inherently safe. FBR has positive sodium expansion coefficient, therefore it has insufficient stability it has been concluded that PWR has safe operation than FBR and RBMK reactors

  13. A NEW HABITAT CLASSIFICATION AND MANUAL FOR STANDARDIZED HABITAT MAPPING

    Directory of Open Access Journals (Sweden)

    A. KUN

    2007-01-01

    Full Text Available Today the documentation of natural heritage with scientific methods but for conservation practice – like mapping of actual vegetation – becomes more and more important. For this purpose mapping guides containing only the names and descriptions of vegetation types are not sufficient. Instead, new, mapping-oriented vegetation classification systems and handbooks are needed. There are different standardised systems fitted to the characteristics of a region already published and used successfully for surveying large territories. However, detailed documentation of the aims and steps of their elaboration is still missing. Here we present a habitat-classification method developed specifically for mapping and the steps of its development. Habitat categories and descriptions reflect site conditions, physiognomy and species composition as well. However, for species composition much lower role was given deliberately than in the phytosociological systems. Recognition and mapping of vegetation types in the field is highly supported by a definition, list of subtypes and list of ‘types not belonging to this habitat category’. Our system is two-dimensional: the first dimension is habitat type, the other is naturalness based habitat quality. The development of the system was conducted in two steps, over 200 mappers already tested it over 7000 field days in different projects.

  14. Bacterial phylogeny structures soil resistomes across habitats

    Science.gov (United States)

    Forsberg, Kevin J.; Patel, Sanket; Gibson, Molly K.; Lauber, Christian L.; Knight, Rob; Fierer, Noah; Dantas, Gautam

    2014-05-01

    Ancient and diverse antibiotic resistance genes (ARGs) have previously been identified from soil, including genes identical to those in human pathogens. Despite the apparent overlap between soil and clinical resistomes, factors influencing ARG composition in soil and their movement between genomes and habitats remain largely unknown. General metagenome functions often correlate with the underlying structure of bacterial communities. However, ARGs are proposed to be highly mobile, prompting speculation that resistomes may not correlate with phylogenetic signatures or ecological divisions. To investigate these relationships, we performed functional metagenomic selections for resistance to 18 antibiotics from 18 agricultural and grassland soils. The 2,895 ARGs we discovered were mostly new, and represent all major resistance mechanisms. We demonstrate that distinct soil types harbour distinct resistomes, and that the addition of nitrogen fertilizer strongly influenced soil ARG content. Resistome composition also correlated with microbial phylogenetic and taxonomic structure, both across and within soil types. Consistent with this strong correlation, mobility elements (genes responsible for horizontal gene transfer between bacteria such as transposases and integrases) syntenic with ARGs were rare in soil by comparison with sequenced pathogens, suggesting that ARGs may not transfer between soil bacteria as readily as is observed between human pathogens. Together, our results indicate that bacterial community composition is the primary determinant of soil ARG content, challenging previous hypotheses that horizontal gene transfer effectively decouples resistomes from phylogeny.

  15. HEDL experimental transient overpower program

    International Nuclear Information System (INIS)

    Hikido, T.; Culley, G.E.

    1976-01-01

    HEDL is conducting a series of experiments to evaluate the performance of Fast Flux Test Facility (FFTF) prototypic fuel pins up to the point of cladding breach. A primary objective of the program is to demonstrate the adequacy of fuel pin and Plant Protective System (PPS) designs for terminated transients. Transient tests of prototypic FFTF fuel pins previously irradiated in the Experimental Breeder Reactor-II (EBR-II) have demonstrated the adequacy of the PPS and fuel pin designs and indicate that a very substantial margin exists between PPS-terminated transients and that required to produce fuel pin cladding failure. Additional experiments are planned to extend the data base to high burnup, high fluence fuel pin specimens

  16. Transient voltage oscillations in coils

    International Nuclear Information System (INIS)

    Chowdhuri, P.

    1985-01-01

    Magnet coils may be excited into internal voltage oscillations by transient voltages. Such oscillations may electrically stress the magnet's dielectric components to many times its normal stress. This may precipitate a dielectric failure, and the attendant prolonged loss of service and costly repair work. Therefore, it is important to know the natural frequencies of oscillations of a magnet during the design stage, and to determine whether the expected switching transient voltages can excite the magnet into high-voltage internal oscillations. The series capacitance of a winding significantly affects its natural frequencies. However, the series capacitance is difficult to calculate, because it may comprise complex capacitance network, consisting of intra- and inter-coil turn-to-turn capacitances of the coil sections. A method of calculating the series capacitance of a winding is proposed. This method is rigorous but simple to execute. The time-varying transient voltages along the winding are also calculated

  17. Transient analysis of DTT rakes

    International Nuclear Information System (INIS)

    Kamath, P.S.; Lahey, R.T. Jr.

    1981-01-01

    This paper presents an analytical model for the determination of the cross-sectionally averaged transient mass flux of a two-phase fluid flowing in a conduit instrumented by a Drag-Disk Turbine Transducer (DTT) Rake and a multibeam gamma densitometer. Parametric studies indicate that for a typical blowdown transient, dynamic effects such as rotor inertia can be important for the turbine-meter. In contrast, for the drag-disk, a frequency response analysis showed that the quasisteady solution is valid below a forcing frequency of about 10 Hz, which is faster than the time scale normally encountered during blowdowns. The model showed reasonably good agreement with full scale transient rake data, where the flow regimes were mostly homogeneous or stratified, thus indicating that the model is suitable for the analysis of a DTT rake. (orig.)

  18. Evolution of microbial pathogens

    National Research Council Canada - National Science Library

    DiRita, Victor J; Seifert, H. Steven

    2006-01-01

    ... A. Hogan vvi ■ CONTENTS 8. Evolution of Pathogens in Soil Rachel Muir and Man-Wah Tan / 131 9. Experimental Models of Symbiotic Host-Microbial Relationships: Understanding the Underpinnings of ...

  19. Wind and sunlight shape microbial diversity in surface waters of the North Pacific Subtropical Gyre.

    Science.gov (United States)

    Bryant, Jessica A; Aylward, Frank O; Eppley, John M; Karl, David M; Church, Matthew J; DeLong, Edward F

    2016-06-01

    Few microbial time-series studies have been conducted in open ocean habitats having low seasonal variability such as the North Pacific Subtropical Gyre (NPSG), where surface waters experience comparatively mild seasonal variation. To better describe microbial seasonal variability in this habitat, we analyzed rRNA amplicon and shotgun metagenomic data over two years at the Hawaii Ocean Time-series Station ALOHA. We postulated that this relatively stable habitat might reveal different environmental factors that influence planktonic microbial community diversity than those previously observed in more seasonally dynamic habitats. Unexpectedly, the data showed that microbial diversity at 25 m was positively correlated with average wind speed 3 to 10 days prior to sampling. In addition, microbial community composition at 25 m exhibited significant correlations with solar irradiance. Many bacterial groups whose relative abundances varied with solar radiation corresponded to taxa known to exhibit strong seasonality in other oceanic regions. Network co-correlation analysis of 25 m communities showed seasonal transitions in composition, and distinct successional cohorts of co-occurring phylogenetic groups. Similar network analyses of metagenomic data also indicated distinct seasonality in genes originating from cyanophage, and several bacterial clades including SAR116 and SAR324. At 500 m, microbial community diversity and composition did not vary significantly with any measured environmental parameters. The minimal seasonal variability in the NPSG facilitated detection of more subtle environmental influences, such as episodic wind variation, on surface water microbial diversity. Community composition in NPSG surface waters varied in response to solar irradiance, but less dramatically than reported in other ocean provinces.

  20. Synthetic Electric Microbial Biosensors

    Science.gov (United States)

    2017-06-10

    domains and DNA-binding domains into a single protein for deregulation of down stream genes of have been favored [10]. Initially experiments with... Germany DISTRIBUTION A. Approved for public release: distribution unlimited.   Talk title: “Synthetic biology based microbial biosensors for the...toolbox” in Heidelberg, Germany Poster title: “Anaerobic whole cell microbial biosensors” Link: http://phdsymposium.embl.org/#home   September, 2014

  1. Transient analysis of multicavity klystrons

    International Nuclear Information System (INIS)

    Lavine, T.L.; Miller, R.H.; Morton, P.L.; Ruth, R.D.

    1988-09-01

    We describe a model for analytic analysis of transients in multicavity klystron output power and phase. Cavities are modeled as resonant circuits, while bunching of the beam is modeled using linear space-charge wave theory. Our analysis has been implemented in a computer program which we use in designing multicavity klystrons with stable output power and phase. We present as examples transient analysis of a relativistic klystron using a magnetic pulse compression modulator, and of a conventional klystron designed to use phase shifting techniques for RF pulse compression. 4 refs., 4 figs

  2. Transient formation of forbidden lines

    International Nuclear Information System (INIS)

    Rosmej, F.B.; Rosmej, O.N.

    1996-01-01

    An explanation of anomalously long time scales in the transient formation of forbidden lines is proposed. The concept is based on a collisionally induced density dependence of the relaxation times of metastable level populations in transient plasma. Generalization leads to an incorporation of diffusion phenomena. We demonstrate this new concept for the simplest atomic system: the He-like isoelectronic sequence. A new interpretation of the observed long duration and anomalously high intensity of spin-forbidden emission in hot plasmas is given. (author)

  3. Transient formation of forbidden lines

    Energy Technology Data Exchange (ETDEWEB)

    Rosmej, F.B. [Bochum Univ., Ruhr (Germany). Inst. fuer Experimentalphysik V; Rosmej, O.N. [VNIIFTRI, Moscow Region (Russian Federation). MISDC

    1996-05-14

    An explanation of anomalously long time scales in the transient formation of forbidden lines is proposed. The concept is based on a collisionally induced density dependence of the relaxation times of metastable level populations in transient plasma. Generalization leads to an incorporation of diffusion phenomena. We demonstrate this new concept for the simplest atomic system: the He-like isoelectronic sequence. A new interpretation of the observed long duration and anomalously high intensity of spin-forbidden emission in hot plasmas is given. (author).

  4. Mining of unexplored habitats for novel chitinases-chiA as a helper gene proxy in metagenomics

    NARCIS (Netherlands)

    Cretoiu, Mariana Silvia; Kielak, Anna Maria; Abu Al-Soud, Waleed; Sorensen, Soren J.; van Elsas, Jan Dirk; Sørensen, S.J.

    The main objective of this study was to assess the abundance and diversity of chitin-degrading microbial communities in ten terrestrial and aquatic habitats in order to provide guidance to the subsequent exploration of such environments for novel chitinolytic enzymes. A combined protocol which

  5. Microbial bioinformatics 2020.

    Science.gov (United States)

    Pallen, Mark J

    2016-09-01

    Microbial bioinformatics in 2020 will remain a vibrant, creative discipline, adding value to the ever-growing flood of new sequence data, while embracing novel technologies and fresh approaches. Databases and search strategies will struggle to cope and manual curation will not be sustainable during the scale-up to the million-microbial-genome era. Microbial taxonomy will have to adapt to a situation in which most microorganisms are discovered and characterised through the analysis of sequences. Genome sequencing will become a routine approach in clinical and research laboratories, with fresh demands for interpretable user-friendly outputs. The "internet of things" will penetrate healthcare systems, so that even a piece of hospital plumbing might have its own IP address that can be integrated with pathogen genome sequences. Microbiome mania will continue, but the tide will turn from molecular barcoding towards metagenomics. Crowd-sourced analyses will collide with cloud computing, but eternal vigilance will be the price of preventing the misinterpretation and overselling of microbial sequence data. Output from hand-held sequencers will be analysed on mobile devices. Open-source training materials will address the need for the development of a skilled labour force. As we boldly go into the third decade of the twenty-first century, microbial sequence space will remain the final frontier! © 2016 The Author. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  6. Maladaptive habitat selection of a migratory passerine bird in a human-modified landscape.

    Directory of Open Access Journals (Sweden)

    Franck A Hollander

    Full Text Available In human-altered environments, organisms may preferentially settle in poor-quality habitats where fitness returns are lower relative to available higher-quality habitats. Such ecological trapping is due to a mismatch between the cues used during habitat selection and the habitat quality. Maladaptive settlement decisions may occur when organisms are time-constrained and have to rapidly evaluate habitat quality based on incomplete knowledge of the resources and conditions that will be available later in the season. During a three-year study, we examined settlement decision-making in the long-distance migratory, open-habitat bird, the Red-backed shrike (Lanius collurio, as a response to recent land-use changes. In Northwest Europe, the shrikes typically breed in open areas under a management regime of extensive farming. In recent decades, Spruce forests have been increasingly managed with large-size cutblocks in even-aged plantations, thereby producing early-successional vegetation areas that are also colonised by the species. Farmland and open areas in forests create mosaics of two different types of habitats that are now occupied by the shrikes. We examined redundant measures of habitat preference (order of settlement after migration and distribution of dominant individuals and several reproductive performance parameters in both habitat types to investigate whether habitat preference is in line with habitat quality. Territorial males exhibited a clear preference for the recently created open areas in forests with higher-quality males settling in this habitat type earlier. Reproductive performance was, however, higher in farmland, with higher nest success, offspring quantity, and quality compared to open areas in forests. The results showed strong among-year consistency and we can therefore exclude a transient situation. This study demonstrates a case of maladaptive habitat selection in a farmland bird expanding its breeding range to human

  7. Trapping Triatominae in Silvatic Habitats

    Directory of Open Access Journals (Sweden)

    Noireau François

    2002-01-01

    Full Text Available Large-scale trials of a trapping system designed to collect silvatic Triatominae are reported. Live-baited adhesive traps were tested in various ecosystems and different triatomine habitats (arboreal and terrestrial. The trials were always successful, with a rate of positive habitats generally over 20% and reaching 48.4% for palm trees of the Amazon basin. Eleven species of Triatominae belonging to the three genera of public health importance (Triatoma, Rhodnius and Panstrongylus were captured. This trapping system provides an effective way to detect the presence of triatomines in terrestrial and arboreal silvatic habitats and represents a promising tool for ecological studies. Various lines of research are contemplated to improve the performance of this trapping system.

  8. Loss and modification of habitat

    Science.gov (United States)

    Lemckert, Francis; Hecnar, Stephen; Pilliod, David S.; Wilkinson, John W.; Heatwole, Harold

    2012-01-01

    Amphibians live in a wide variety of habitats around the world, many of which have been modified or destroyed by human activities. Most species have unique life history characteristics adapted to specific climates, habitats (e.g., lentic, lotic, terrestrial, arboreal, fossorial, amphibious), and local conditions that provide suitable areas for reproduction, development and growth, shelter from environmental extremes, and predation, as well as connectivity to other populations or habitats. Although some species are entirely aquatic or terrestrial, most amphibians, as their name implies, lead a dual life and require a mosaic of habitats in both aquatic and terrestrial ecosystems. With over 6 billion people on Earth, most species are now persisting in habitats that have been directly or indirectly influenced by human activities. Some species have disappeared where their habitats have been completely destroyed, reduced, or rendered unsuitable. Habitat loss and degradation are widely considered by most researchers as the most important causes of amphibian population decline globally (Barinaga 1990; Wake and Morowitz 1991; Alford and Richards 1999). In this chapter, a background on the diverse habitat requirements of amphibians is provided, followed by a discussion of the effects of urbanization, agriculture, livestock grazing, timber production and harvesting, fire and hazardous fuel management, and roads on amphibians and their habitats. Also briefly discussed is the influence on amphibian habitats of natural disturbances, such as extreme weather events and climate change, given the potential for human activities to impact climate in the longer term. For amphibians in general, microhabitats are of greater importance than for other vertebrates. As ectotherms with a skin that is permeable to water and with naked gelatinous eggs, amphibians are physiologically constrained to be active during environmental conditions that provide appropriate body temperatures and adequate

  9. Wildlife habitats in managed rangelands—the Great Basin of southeastern Oregon: manmade habitats.

    Science.gov (United States)

    Chris Maser; Jack Ward Thomas; Ira David Luman; Ralph. Anderson

    1979-01-01

    Manmade structures on rangelands provide specialized habitats for some species. These habitats and how they function as specialized habitat features are examined in this publication. The relationships of the wildlife of the Great Basin to such structures are detailed.

  10. Geomorphology and Sustainable Subsistence Habitats

    Science.gov (United States)

    Johnson, A. C.; Kruger, L. E.

    2016-02-01

    Climatic, tectonic, and human-related impacts are changing the distribution of shoreline habitats and associated species used as food resources. There is a need to summarize current and future shoreline geomorphic - biotic relationships and better understand potential impacts to native customary and traditional gathering patterns. By strategically integrating Native knowledge and observations, we create an inclusive vulnerability assessment strategy resulting in a win-win opportunity for resource users and research scientists alike. We merged the NOAA ShoreZone database with results from over sixty student intern discussions in six southeast Alaska Native communities. Changes in shore width and unit length were derived using near shore bathymetry depths and available isostatic rebound, tectonic movement, and rates of sea level rise. Physical attributes including slope, substrate, and exposure were associated with presence and abundance of specific species. Student interns, selected by Tribes and Tribal associations, conducted resource-based discussions with community members to summarize species use, characteristics of species habitat, transportation used to access collection areas, and potential threats to habitats. Geomorphic trends and community observations were summarized to assess potential threats within a spatial context. Given current measured rates of uplift and sea level rise, 2.4 to 0 m of uplift along with 0.20 m of sea level rise is expected in the next 100 years. Coastlines of southeast Alaska will be subject to both drowning (primarily to the south) and emergence (primarily to the north). We predict decreases in estuary and sediment-dominated shoreline length and an increase in rocky habitats. These geomorphic changes, combined with resident's concerns, highlight six major interrelated coastal vulnerabilities including: (1) reduction of clam and clam habitat quantity and quality, (2) reduction in chiton quality and quantity, (3) harmful expansion of

  11. Transient attenuation in optical fibers

    International Nuclear Information System (INIS)

    Hopkins, A.A.; Kelly, R.E.; Looney, L.D.; Lyons, P.B.

    1984-01-01

    Low and high energy pulsed electron beams were used to generate radiation-induced transient attenuation in high-OH, Suprasil core, PCS fibers, demonstrating the energy dependence of the radiation damage and recovery mechanisms. A radiation resistant low-OH fiber was studied and its performance contrasted to that of high-OH materials. Several fibers with differing core compositions were also studied

  12. Charging transient in polyvinyl formal

    Indian Academy of Sciences (India)

    Unknown

    401–406. © Indian Academy of Sciences. 401. Charging transient in polyvinyl formal. P K KHARE*, P L JAIN† and R K PANDEY‡. Department of Postgraduate Studies & Research in Physics & Electronics, Rani Durgavati University,. Jabalpur 482 001, India. †Department of Physics, Government PG College, Damoh 470 ...

  13. Transient filament stretching rheometer II

    DEFF Research Database (Denmark)

    Kolte, Mette Irene; Rasmussen, Henrik K.; Hassager, Ole

    1997-01-01

    The Lagrangian sspecification is used to simulate the transient stretching filament rheometer. Simulations are performed for dilute PIB-solutions modeled as a four mode Oldroyd-B fluid and a semidilute PIB-solution modeled as a non-linear single integral equation. The simulations are compared...

  14. Fuel rod behaviour during transients

    International Nuclear Information System (INIS)

    Hughes, H.; Haste, T.J.; Cameron, R.F.; Sinclair, J.E.

    1982-04-01

    The fuel pin performance code SLEUTH, the transient codes FRAP-T5 and TRAFIC and the clad deformation code CANSWEL-2 are described. It is shown how the codes treat gas release, pin cooling, cladding deformation and interaction, gap conductance etc. The materials properties used are indicated. (author)

  15. Simulation Model of a Transient

    DEFF Research Database (Denmark)

    Jauch, Clemens; Sørensen, Poul; Bak-Jensen, Birgitte

    2005-01-01

    This paper describes the simulation model of a controller that enables an active-stall wind turbine to ride through transient faults. The simulated wind turbine is connected to a simple model of a power system. Certain fault scenarios are specified and the turbine shall be able to sustain operati...

  16. Stationary and Transient Response Statistics

    DEFF Research Database (Denmark)

    Madsen, Peter Hauge; Krenk, Steen

    1982-01-01

    The covariance functions for the transient response of a linear MDOF-system due to stationary time limited excitation with an arbitrary frequency content are related directly to the covariance functions of the stationary response. For rational spectral density functions closed form expressions fo...

  17. Transient anisotropic magnetic field calculation

    International Nuclear Information System (INIS)

    Jesenik, Marko; Gorican, Viktor; Trlep, Mladen; Hamler, Anton; Stumberger, Bojan

    2006-01-01

    For anisotropic magnetic material, nonlinear magnetic characteristics of the material are described with magnetization curves for different magnetization directions. The paper presents transient finite element calculation of the magnetic field in the anisotropic magnetic material based on the measured magnetization curves for different magnetization directions. For the verification of the calculation method some results of the calculation are compared with the measurement

  18. Habitat classification modelling with incomplete data: Pushing the habitat envelope

    Science.gov (United States)

    Phoebe L. Zarnetske; Thomas C. Edwards; Gretchen G. Moisen

    2007-01-01

    Habitat classification models (HCMs) are invaluable tools for species conservation, land-use planning, reserve design, and metapopulation assessments, particularly at broad spatial scales. However, species occurrence data are often lacking and typically limited to presence points at broad scales. This lack of absence data precludes the use of many statistical...

  19. [Transient amnesia in the elderly].

    Science.gov (United States)

    Sellal, François

    2006-03-01

    The two main aetiologies of transient amnesia in the elderly are idiopathic transient global amnesia (TGA) and iatrogenic or toxic amnesia. Vascular and epileptic amnesia are less common. According to the literature, transient psychogenic amnesia, which is a frequent cause of amnesia at age 30 to 50, is very rare in the elderly. TGA is the prototypical picture of transient amnesia. It occurs more often after age 50, with no identified cause, even if some authors accept emotional stress or minor head trauma as occasional precipitants. The mechanism of TGA remains a matter of discussion. It may be the consequence of a spreading depression similar to that described in migraine with aura, but other arguments support an ischemic mechanism. Iatrogenic amnesias are mainly caused by benzodiazepines (BZs) or anticholinergics. The former may occur in a non-anxious subject, who is not a usual consumer of BZ and takes a single dose. The latter are more often due to a hypersensitivity to anticholinergic drugs, in particular in patients presenting with a covert, incipient Alzheimer's disease. A vascular origin must be considered when amnesia is accompanied by other neurological symptoms, and when the regression of the amnesic disorder is slow, lasting several days. It results from lesions involving various mechanisms and locations, mainly subcortical. Partial seizures, most often mesio-temporal, more rarely frontal, may be the cause of transient amnesia in the elderly, in the absence of a past history of epilepsy. The red flag supportive of an epileptic origin is the repetition of stereotyped amnesic episodes. EEG demonstration of seizures may be difficult and the response to antiepileptic drugs effective on partial seizures is usually good.

  20. Research of the transient management in TQNPC

    International Nuclear Information System (INIS)

    Guo Longzhang; Lin Chuanqing

    2008-01-01

    Transient management is the basic technical subject in nuclear power plant. Since the Third Qinshan nuclear power company (TQNPC) successful completes the commissioning in 2003, the transient management work start at the transient management item selection and the flow definition. Now TQNPC have a complete transient management system and the management flow. In the last two years, TNQPC have finished the historic transient data collection for two units, and confirmed that the plant's key systems and equipments are at safe state. The development of the transient management subject would build a reliable foundation for the plant safe operation, plant lifetime management and periodic safety review. (author)

  1. A niche for cyanobacteria producing chlorophyll f within a microbial mat.

    Science.gov (United States)

    Ohkubo, Satoshi; Miyashita, Hideaki

    2017-10-01

    Acquisition of additional photosynthetic pigments enables photosynthetic organisms to survive in particular niches. To reveal the ecological significance of chlorophyll (Chl) f, we investigated the distribution of Chl and cyanobacteria within two microbial mats. In a 7-mm-thick microbial mat beneath the running water of the Nakabusa hot spring, Japan, Chl f was only distributed 4.0-6.5 mm below the surface, where the intensity of far-red light (FR) was higher than that of photosynthetically active radiation (PAR). In the same mat, two ecotypes of Synechococcus and two ecotypes of Chl f-producing Leptolyngbya were detected in the upper and deeper layers, respectively. Only the Leptolyngbya strains could grow when FR was the sole light source. These results suggest that the deeper layer of the microbial mat was a habitat for Chl f-producing cyanobacteria, and Chl f enabled them to survive in a habitat with little PAR.

  2. Microbial conversion technologies

    Energy Technology Data Exchange (ETDEWEB)

    Lau, P. [National Research Council of Canada, Ottawa, ON (Canada). Bioconversion and Sustainable Development

    2006-07-01

    Microbes are a biomass and an valuable resource. This presentation discussed microbial conversion technologies along with background information on microbial cells, their characteristics and microbial diversity. Untapped opportunities for microbial conversion were identified. Metagenomic and genome mining approaches were also discussed, as they can provide access to uncultivated or unculturable microorganisms in communal populations and are an unlimited resource for biocatalysts, novel genes and metabolites. Genome mining was seen as an economical approach. The presentation also emphasized that the development of microbial biorefineries would require significant insights into the relevant microorganisms and that biocatalysts were the ultimate in sustainability. In addition, the presentation discussed the natural fibres initiative for biochemicals and biomaterials. Anticipated outputs were identified and work in progress of a new enzyme-retting cocktail to provide diversity and/or consistency in fibre characteristics for various applications were also presented. It was concluded that it is necessary to leverage understanding of biological processes to produce bioproducts in a clean and sustainable manner. tabs., figs.

  3. Analysis of Low-Biomass Microbial Communities in the Deep Biosphere.

    Science.gov (United States)

    Morono, Y; Inagaki, F

    2016-01-01

    Over the past few decades, the subseafloor biosphere has been explored by scientific ocean drilling to depths of about 2.5km below the seafloor. Although organic-rich anaerobic sedimentary habitats in the ocean margins harbor large numbers of microbial cells, microbial populations in ultraoligotrophic aerobic sedimentary habitats in the open ocean gyres are several orders of magnitude less abundant. Despite advances in cultivation-independent molecular ecological techniques, exploring the low-biomass environment remains technologically challenging, especially in the deep subseafloor biosphere. Reviewing the historical background of deep-biosphere analytical methods, the importance of obtaining clean samples and tracing contamination, as well as methods for detecting microbial life, technological aspects of molecular microbiology, and detecting subseafloor metabolic activity will be discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Microbial ecology and biogeochemistry of continental Antarctic soils

    Directory of Open Access Journals (Sweden)

    Don A Cowan

    2014-04-01

    Full Text Available The Antarctica Dry Valleys are regarded as the coldest hyperarid desert system on Earth. While a wide variety of environmental stressors including very low minimum temperatures, frequent freeze-thaw cycles and low water availability impose severe limitations to life, suitable niches for abundant microbial colonization exist. Antarctic desert soils contain much higher levels of microbial diversity than previously thought. Edaphic niches, including cryptic and refuge habitats, microbial mats and permafrost soils all harbour microbial communities which drive key biogeochemical cycling processes. For example, lithobionts (hypoliths and endoliths possess a genetic capacity for nitrogen and carbon cycling, polymer degradation and other system processes. Nitrogen fixation rates of hypoliths, as assessed through acetylene reduction assays, suggest that these communities are a significant input source for nitrogen into these oligotrophic soils. Here we review aspects of microbial diversity in Antarctic soils with an emphasis on functionality and capacity. We assess current knowledge regarding adaptations to Antarctic soil environments and highlight the current threats to Antarctic desert soil communities.

  5. Microbial ecology and biogeochemistry of continental Antarctic soils.

    Science.gov (United States)

    Cowan, Don A; Makhalanyane, Thulani P; Dennis, Paul G; Hopkins, David W

    2014-01-01

    The Antarctica Dry Valleys are regarded as the coldest hyperarid desert system on Earth. While a wide variety of environmental stressors including very low minimum temperatures, frequent freeze-thaw cycles and low water availability impose severe limitations to life, suitable niches for abundant microbial colonization exist. Antarctic desert soils contain much higher levels of microbial diversity than previously thought. Edaphic niches, including cryptic and refuge habitats, microbial mats and permafrost soils all harbor microbial communities which drive key biogeochemical cycling processes. For example, lithobionts (hypoliths and endoliths) possess a genetic capacity for nitrogen and carbon cycling, polymer degradation, and other system processes. Nitrogen fixation rates of hypoliths, as assessed through acetylene reduction assays, suggest that these communities are a significant input source for nitrogen into these oligotrophic soils. Here we review aspects of microbial diversity in Antarctic soils with an emphasis on functionality and capacity. We assess current knowledge regarding adaptations to Antarctic soil environments and highlight the current threats to Antarctic desert soil communities.

  6. Instream Physical Habitat Modelling Types

    DEFF Research Database (Denmark)

    Conallin, John; Boegh, Eva; Krogsgaard, Jørgen

    2010-01-01

    The introduction of the EU Water Framework Directive (WFD) is providing member state water resource managers with significant challenges in relation to meeting the deadline for 'Good Ecological Status' by 2015. Overall, instream physical habitat modelling approaches have advantages and disadvanta......The introduction of the EU Water Framework Directive (WFD) is providing member state water resource managers with significant challenges in relation to meeting the deadline for 'Good Ecological Status' by 2015. Overall, instream physical habitat modelling approaches have advantages...... suit their situations. This paper analyses the potential of different methods available for water managers to assess hydrological and geomorphological impacts on the habitats of stream biota, as requested by the WFD. The review considers both conventional and new advanced research-based instream...... physical habitat models. In parametric and non-parametric regression models, model assumptions are often not satisfied and the models are difficult to transfer to other regions. Research-based methods such as the artificial neural networks and individual-based modelling have promising potential as water...

  7. Habitats: staging life and art

    DEFF Research Database (Denmark)

    Andersen, Peter Bøgh

    2004-01-01

    The paper presents the concept of habitat. It is a bounded chunk of space/time that isdesigned to accommodate a delimited set of activities. It accommodates the activities by in-cludingphysical artefacts that can be used in the activities and signs that offer activity-relevantinformation. The hab...

  8. Oak woodlands as wildlife habitat

    Science.gov (United States)

    W. Tietje; K. Purcell; S. Drill

    2005-01-01

    This chapter provides local planners and policymakers with information on the diversity and abundance of oak woodland wildlife, wildlife habitat needs, and how local planning activities can influence wildlife abundance and diversity. Federal and state laws, particularly the federal and California Endangered Species Act and the California Environmental Quality Act (CEQA...

  9. Habitat factors influencing the distribution of Cymbopogon validus in ...

    African Journals Online (AJOL)

    Habitat factors influencing the distribution of Cymbopogon validus in Mkambati Game Reserve, Transkei. ... disturbance; game reserve; grassland; grasslands; habitat conditions; habitat factors; mkambati game ... AJOL African Journals Online.

  10. Mapping Thermal Habitat of Ectotherms Based on Behavioral Thermoregulation in a Controlled Thermal Environment

    Science.gov (United States)

    Fei, T.; Skidmore, A.; Liu, Y.

    2012-07-01

    Thermal environment is especially important to ectotherm because a lot of physiological functions rely on the body temperature such as thermoregulation. The so-called behavioural thermoregulation function made use of the heterogeneity of the thermal properties within an individual's habitat to sustain the animal's physiological processes. This function links the spatial utilization and distribution of individual ectotherm with the thermal properties of habitat (thermal habitat). In this study we modelled the relationship between the two by a spatial explicit model that simulates the movements of a lizard in a controlled environment. The model incorporates a lizard's transient body temperatures with a cellular automaton algorithm as a way to link the physiology knowledge of the animal with the spatial utilization of its microhabitat. On a larger spatial scale, 'thermal roughness' of the habitat was defined and used to predict the habitat occupancy of the target species. The results showed the habitat occupancy can be modelled by the cellular automaton based algorithm at a smaller scale, and can be modelled by the thermal roughness index at a larger scale.

  11. Microbial co-occurrence relationships in the human microbiome.

    Directory of Open Access Journals (Sweden)

    Karoline Faust

    Full Text Available The healthy microbiota show remarkable variability within and among individuals. In addition to external exposures, ecological relationships (both oppositional and symbiotic between microbial inhabitants are important contributors to this variation. It is thus of interest to assess what relationships might exist among microbes and determine their underlying reasons. The initial Human Microbiome Project (HMP cohort, comprising 239 individuals and 18 different microbial habitats, provides an unprecedented resource to detect, catalog, and analyze such relationships. Here, we applied an ensemble method based on multiple similarity measures in combination with generalized boosted linear models (GBLMs to taxonomic marker (16S rRNA gene profiles of this cohort, resulting in a global network of 3,005 significant co-occurrence and co-exclusion relationships between 197 clades occurring throughout the human microbiome. This network revealed strong niche specialization, with most microbial associations occurring within body sites and a number of accompanying inter-body site relationships. Microbial communities within the oropharynx grouped into three distinct habitats, which themselves showed no direct influence on the composition of the gut microbiota. Conversely, niches such as the vagina demonstrated little to no decomposition into region-specific interactions. Diverse mechanisms underlay individual interactions, with some such as the co-exclusion of Porphyromonaceae family members and Streptococcus in the subgingival plaque supported by known biochemical dependencies. These differences varied among broad phylogenetic groups as well, with the Bacilli and Fusobacteria, for example, both enriched for exclusion of taxa from other clades. Comparing phylogenetic versus functional similarities among bacteria, we show that dominant commensal taxa (such as Prevotellaceae and Bacteroides in the gut often compete, while potential pathogens (e.g. Treponema and

  12. Microbial Co-occurrence Relationships in the Human Microbiome

    Science.gov (United States)

    Izard, Jacques; Segata, Nicola; Gevers, Dirk

    2012-01-01

    The healthy microbiota show remarkable variability within and among individuals. In addition to external exposures, ecological relationships (both oppositional and symbiotic) between microbial inhabitants are important contributors to this variation. It is thus of interest to assess what relationships might exist among microbes and determine their underlying reasons. The initial Human Microbiome Project (HMP) cohort, comprising 239 individuals and 18 different microbial habitats, provides an unprecedented resource to detect, catalog, and analyze such relationships. Here, we applied an ensemble method based on multiple similarity measures in combination with generalized boosted linear models (GBLMs) to taxonomic marker (16S rRNA gene) profiles of this cohort, resulting in a global network of 3,005 significant co-occurrence and co-exclusion relationships between 197 clades occurring throughout the human microbiome. This network revealed strong niche specialization, with most microbial associations occurring within body sites and a number of accompanying inter-body site relationships. Microbial communities within the oropharynx grouped into three distinct habitats, which themselves showed no direct influence on the composition of the gut microbiota. Conversely, niches such as the vagina demonstrated little to no decomposition into region-specific interactions. Diverse mechanisms underlay individual interactions, with some such as the co-exclusion of Porphyromonaceae family members and Streptococcus in the subgingival plaque supported by known biochemical dependencies. These differences varied among broad phylogenetic groups as well, with the Bacilli and Fusobacteria, for example, both enriched for exclusion of taxa from other clades. Comparing phylogenetic versus functional similarities among bacteria, we show that dominant commensal taxa (such as Prevotellaceae and Bacteroides in the gut) often compete, while potential pathogens (e.g. Treponema and Prevotella in the

  13. Microbial ecology in a future climate: effects of temperature and moisture on microbial communities of two boreal fens.

    Science.gov (United States)

    Peltoniemi, Krista; Laiho, Raija; Juottonen, Heli; Kiikkilä, Oili; Mäkiranta, Päivi; Minkkinen, Kari; Pennanen, Taina; Penttilä, Timo; Sarjala, Tytti; Tuittila, Eeva-Stiina; Tuomivirta, Tero; Fritze, Hannu

    2015-07-01

    Impacts of warming with open-top chambers on microbial communities in wet conditions and in conditions resulting from moderate water-level drawdown (WLD) were studied across 0-50 cm depth in northern and southern boreal sedge fens. Warming alone decreased microbial biomass especially in the northern fen. Impact of warming on microbial PLFA and fungal ITS composition was more obvious in the northern fen and linked to moisture regime and sample depth. Fungal-specific PLFA increased in the surface peat in the drier regime and decreased in layers below 10 cm in the wet regime after warming. OTUs representing Tomentella and Lactarius were observed in drier regime and Mortierella in wet regime after warming in the northern fen. The ectomycorrhizal fungi responded only to WLD. Interestingly, warming together with WLD decreased archaeal 16S rRNA copy numbers in general, and fungal ITS copy numbers in the northern fen. Expectedly, many results indicated that microbial response on warming may be linked to the moisture regime. Results indicated that microbial community in the northern fen representing Arctic soils would be more sensitive to environmental changes. The response to future climate change clearly may vary even within a habitat type, exemplified here by boreal sedge fen. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  14. Nuclear power plant transients: where are we

    International Nuclear Information System (INIS)

    Majumdar, D.

    1984-05-01

    This document is in part a postconference review and summary of the American Nuclear Society sponsored Anticipated and Abnormal Plant Transients in Light Water Reactors Conference held in Jackson, Wyoming, September 26-29, 1983, and in part a reflection upon the issues of plant transients and their impact on the viability of nuclear power. This document discusses state-of-the-art knowledge, deficiencies, and future directions in the plant transients area as seen through this conference. It describes briefly what was reported in this conference, emphasizes areas where it is felt there is confidence in the nuclear industry, and also discusses where the experts did not have a consensus. Areas covered in the document include major issues in operational transients, transient management, transient events experience base, the status of the analytical tools and their capabilities, probabilistic risk assessment applications in operational transients, and human factors impact on plant transients management

  15. Stream Habitat Reach Summary - NCWAP [ds158

    Data.gov (United States)

    California Natural Resource Agency — The Stream Habitat - NCWAP - Reach Summary [ds158] shapefile contains in-stream habitat survey data summarized to the stream reach level. It is a derivative of the...

  16. Chinook Critical Habitat, Coast - NOAA [ds124

    Data.gov (United States)

    California Department of Resources — This layer depicts areas designated for Chinook Critical Habitat as well as habitat type and quality in the California Coastal Evolutionary Significant Unit (ESU -...

  17. A Conceptual Approach to Recreation Habitat Analysis

    National Research Council Canada - National Science Library

    Hamilton, H. R

    1996-01-01

    .... The Habitat Evaluation Procedures (HEP) is a commonly used technique for assessing human impacts on the vigor of wildlife species, and serves as the model for the Recreation Habitat Analysis Method (RHAM...

  18. Beaked Whale Habitat Characterization and Prediction

    National Research Council Canada - National Science Library

    Ward, Jessica A; Mitchell, Glenn H; Farak, Amy M; Keane, Ellen P

    2005-01-01

    The objective of this study was to characterize known beaked whale habitat and create a predictive beaked whale habitat model of the Gulf of Mexico and east coast of the United States using available...

  19. Pacific Northwest Salmon Habitat Project Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In the Pacific Northwest Salmon Habitat Project Database Across the Pacific Northwest, both public and private agents are working to improve riverine habitat for a...

  20. Nonlinear Diffusion and Transient Osmosis

    International Nuclear Information System (INIS)

    Igarashi, Akira; Rondoni, Lamberto; Botrugno, Antonio; Pizzi, Marco

    2011-01-01

    We investigate both analytically and numerically the concentration dynamics of a solution in two containers connected by a narrow and short channel, in which diffusion obeys a porous medium equation. We also consider the variation of the pressure in the containers due to the flow of matter in the channel. In particular, we identify a phenomenon, which depends on the transport of matter across nano-porous membranes, which we call ''transient osmosis . We find that nonlinear diffusion of the porous medium equation type allows numerous different osmotic-like phenomena, which are not present in the case of ordinary Fickian diffusion. Experimental results suggest one possible candidate for transiently osmotic processes. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  1. Fast thermal transients on valve

    International Nuclear Information System (INIS)

    Ferjancic, M.; Stok, B.; Halilovic, M.; Koc, P.; Mole, N.; Otrin, Z.; Kotar, A.

    2007-01-01

    One of the regulatory body methods to supervise nuclear safety of a nuclear power plant is a review of plant modifications and evaluation of their impact on plant operating experience. The Slovenian Nuclear Safety Administration (SNSA) licensed in April 2003 the use of leak-before-break (LBB) methodology in the Krsko NPP for the primary loop including surge line and connecting pipelines with minimal diameter of 6 inch. The SNSA decision based also on fracture mechanics analyses that include direct pipe failure mechanisms such as water hammer, creep damage, erosion and corrosion, fatigue and environmental conditions over the entire life of the plant. The evaluation of the operating transients pointed out, that presumed loadings, used for the LBB analysis, did not incorporate all the fast thermal transients data. For that purpose the SNSA requested Faculty of Mechanical Engineering (FS) in Ljubljana to perform additional analyses. The results of the analysis shall confirm the validity of the LBB analysis. (author)

  2. Pressure transient in liquid lines

    International Nuclear Information System (INIS)

    Sun, J.G.; Wang, X.Q.

    1995-01-01

    The pressure surge that results from a step change of flow in liquid pipelines, commonly known as water hammer, was analyzed by an eigenfunction method. A differential-integral Pressure wave equation and a linearized velocity equation were derived from the equations of mass and momentum conservation. Waveform distortion due to viscous dissipation and pipe-wall elastic expansion is characterized by a dimensionless transmission number K. The pressure surge condition, which is mathematically singular, was used in the solution procedure. The exact solutions from numerical calculation of the differential-integral equation provide a complete Pressure transient in the pipe. The problems are also calculated With the general-purpose computer code COMMIX, which solves the exact mass conservation equation and Navier-Stokes equations. These solutions were compared with published experimental results, and agreement was good. The effect of turbulence on the pressure transient is discussed in the light of COMMIX calculational results

  3. Superresolution microscopy with transient binding.

    Science.gov (United States)

    Molle, Julia; Raab, Mario; Holzmeister, Susanne; Schmitt-Monreal, Daniel; Grohmann, Dina; He, Zhike; Tinnefeld, Philip

    2016-06-01

    For single-molecule localization based superresolution, the concentration of fluorescent labels has to be thinned out. This is commonly achieved by photophysically or photochemically deactivating subsets of molecules. Alternatively, apparent switching of molecules can be achieved by transient binding of fluorescent labels. Here, a diffusing dye yields bright fluorescent spots when binding to the structure of interest. As the binding interaction is weak, the labeling is reversible and the dye ligand construct diffuses back into solution. This approach of achieving superresolution by transient binding (STB) is reviewed in this manuscript. Different realizations of STB are discussed and compared to other localization-based superresolution modalities. We propose the development of labeling strategies that will make STB a highly versatile tool for superresolution microscopy at highest resolution. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Electromagnetic Transients in Power Cables

    DEFF Research Database (Denmark)

    Silva, Filipe Faria Da; Bak, Claus Leth

    . The chapter ends by proposing a systematic method that can be used when doing the insulation co-ordination study for a line, as well as the modelling requirements, both modelling depth and modelling detail of the equipment, for the study of the different types of transients followed by a step-by-step generic...... typically used for the screens of cables (both-ends bonding and cross-boding) and also presents methods that can be used to estimate the maximum current of a cable for different types of soils, i.e. thermal calculations. The end of the chapter introduces the shunt reactor, which is an important element...... detail of the equipment, for the study of the different types of transients followed by a step-by-step generic example....

  5. Community Structure of Lithotrophically-Driven Hydrothermal Microbial Mats from the Mariana Arc and Back-Arc

    Directory of Open Access Journals (Sweden)

    Kevin W. Hager

    2017-08-01

    Full Text Available The Mariana region exhibits a rich array of hydrothermal venting conditions in a complex geological setting, which provides a natural laboratory to study the influence of local environmental conditions on microbial community structure as well as large-scale patterns in microbial biogeography. We used high-throughput amplicon sequencing of the bacterial small subunit (SSU rRNA gene from 22 microbial mats collected from four hydrothermally active locations along the Mariana Arc and back-arc to explore the structure of lithotrophically-based microbial mat communities. The vent effluent was classified as iron- or sulfur-rich corresponding with two distinct community types, dominated by either Zetaproteobacteria or Epsilonproteobacteria, respectively. The Zetaproteobacterial-based communities had the highest richness and diversity, which supports the hypothesis that Zetaproteobacteria function as ecosystem engineers creating a physical habitat within a chemical environment promoting enhanced microbial diversity. Gammaproteobacteria were also high in abundance within the iron-dominated mats and some likely contribute to primary production. In addition, we also compare sampling scale, showing that bulk sampling of microbial mats yields higher diversity than micro-scale sampling. We present a comprehensive analysis and offer new insights into the community structure and diversity of lithotrophically-driven microbial mats from a hydrothermal region associated with high microbial biodiversity. Our study indicates an important functional role of for the Zetaproteobacteria altering the mat habitat and enhancing community interactions and complexity.

  6. EVA Suit Microbial Leakage Investigation

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this project is to collect microbial samples from various EVA suits to determine how much microbial contamination is typically released during...

  7. LLL transient-electromagnetics-measurement facility

    International Nuclear Information System (INIS)

    Deadrick, F.J.; Miller, E.K.; Hudson, H.G.

    1975-01-01

    The operation and hardware of the Lawrence Livermore Laboratory's transient-electromagnetics (EM)-measurement facility are described. The transient-EM range is useful for determining the time-domain transient responses of structures to incident EM pulses. To illustrate the accuracy and utility of the EM-measurement facility, actual experimental measurements are compared to numerically computed values

  8. Learning from anticipated and abnormal plant transients

    International Nuclear Information System (INIS)

    Varnado, B.

    1983-01-01

    A report is given of the American Nuclear Society topical meeting on Anticipated and Abnormal Transients in Light Water Reactors held in Jackson, Wyoming in September 1983. Industry involvement in the evaluation of operating experience, human error contributions, transient management, thermal hydraulic modelling, the role of probabilistic risk assessment and the cost of transient incidents are discussed. (U.K.)

  9. A transient absorption study of allophycocyanin

    Indian Academy of Sciences (India)

    Transient dynamics of allophycocyanin trimers and monomers are observed by using the pump-probe, transient absorption technique. The origin of spectral components of the transient absorption spectra is discussed in terms of both kinetics and spectroscopy. We find that the energy gap between the ground and excited ...

  10. Adaptive sampling of AEM transients

    Science.gov (United States)

    Di Massa, Domenico; Florio, Giovanni; Viezzoli, Andrea

    2016-02-01

    This paper focuses on the sampling of the electromagnetic transient as acquired by airborne time-domain electromagnetic (TDEM) systems. Typically, the sampling of the electromagnetic transient is done using a fixed number of gates whose width grows logarithmically (log-gating). The log-gating has two main benefits: improving the signal to noise (S/N) ratio at late times, when the electromagnetic signal has amplitudes equal or lower than the natural background noise, and ensuring a good resolution at the early times. However, as a result of fixed time gates, the conventional log-gating does not consider any geological variations in the surveyed area, nor the possibly varying characteristics of the measured signal. We show, using synthetic models, how a different, flexible sampling scheme can increase the resolution of resistivity models. We propose a new sampling method, which adapts the gating on the base of the slope variations in the electromagnetic (EM) transient. The use of such an alternative sampling scheme aims to get more accurate inverse models by extracting the geoelectrical information from the measured data in an optimal way.

  11. Transient virulence of emerging pathogens.

    Science.gov (United States)

    Bolker, Benjamin M; Nanda, Arjun; Shah, Dharmini

    2010-05-06

    Should emerging pathogens be unusually virulent? If so, why? Existing theories of virulence evolution based on a tradeoff between high transmission rates and long infectious periods imply that epidemic growth conditions will select for higher virulence, possibly leading to a transient peak in virulence near the beginning of an epidemic. This transient selection could lead to high virulence in emerging pathogens. Using a simple model of the epidemiological and evolutionary dynamics of emerging pathogens, along with rough estimates of parameters for pathogens such as severe acute respiratory syndrome, West Nile virus and myxomatosis, we estimated the potential magnitude and timing of such transient virulence peaks. Pathogens that are moderately evolvable, highly transmissible, and highly virulent at equilibrium could briefly double their virulence during an epidemic; thus, epidemic-phase selection could contribute significantly to the virulence of emerging pathogens. In order to further assess the potential significance of this mechanism, we bring together data from the literature for the shapes of tradeoff curves for several pathogens (myxomatosis, HIV, and a parasite of Daphnia) and the level of genetic variation for virulence for one (myxomatosis). We discuss the need for better data on tradeoff curves and genetic variance in order to evaluate the plausibility of various scenarios of virulence evolution.

  12. Cortical computations via transient attractors.

    Directory of Open Access Journals (Sweden)

    Oliver L C Rourke

    Full Text Available The ability of sensory networks to transiently store information on the scale of seconds can confer many advantages in processing time-varying stimuli. How a network could store information on such intermediate time scales, between typical neurophysiological time scales and those of long-term memory, is typically attributed to persistent neural activity. An alternative mechanism which might allow for such information storage is through temporary modifications to the neural connectivity which decay on the same second-long time scale as the underlying memories. Earlier work that has explored this method has done so by emphasizing one attractor from a limited, pre-defined set. Here, we describe an alternative, a Transient Attractor network, which can learn any pattern presented to it, store several simultaneously, and robustly recall them on demand using targeted probes in a manner reminiscent of Hopfield networks. We hypothesize that such functionality could be usefully embedded within sensory cortex, and allow for a flexibly-gated short-term memory, as well as conferring the ability of the network to perform automatic de-noising, and separation of input signals into distinct perceptual objects. We demonstrate that the stored information can be refreshed to extend storage time, is not sensitive to noise in the system, and can be turned on or off by simple neuromodulation. The diverse capabilities of transient attractors, as well as their resemblance to many features observed in sensory cortex, suggest the possibility that their actions might underlie neural processing in many sensory areas.

  13. Cortical computations via transient attractors.

    Science.gov (United States)

    Rourke, Oliver L C; Butts, Daniel A

    2017-01-01

    The ability of sensory networks to transiently store information on the scale of seconds can confer many advantages in processing time-varying stimuli. How a network could store information on such intermediate time scales, between typical neurophysiological time scales and those of long-term memory, is typically attributed to persistent neural activity. An alternative mechanism which might allow for such information storage is through temporary modifications to the neural connectivity which decay on the same second-long time scale as the underlying memories. Earlier work that has explored this method has done so by emphasizing one attractor from a limited, pre-defined set. Here, we describe an alternative, a Transient Attractor network, which can learn any pattern presented to it, store several simultaneously, and robustly recall them on demand using targeted probes in a manner reminiscent of Hopfield networks. We hypothesize that such functionality could be usefully embedded within sensory cortex, and allow for a flexibly-gated short-term memory, as well as conferring the ability of the network to perform automatic de-noising, and separation of input signals into distinct perceptual objects. We demonstrate that the stored information can be refreshed to extend storage time, is not sensitive to noise in the system, and can be turned on or off by simple neuromodulation. The diverse capabilities of transient attractors, as well as their resemblance to many features observed in sensory cortex, suggest the possibility that their actions might underlie neural processing in many sensory areas.

  14. Mechanisms Affecting Population Density in Fragmented Habitat

    Directory of Open Access Journals (Sweden)

    Lutz Tischendorf

    2005-06-01

    Full Text Available We conducted a factorial simulation experiment to analyze the relative importance of movement pattern, boundary-crossing probability, and mortality in habitat and matrix on population density, and its dependency on habitat fragmentation, as well as inter-patch distance. We also examined how the initial response of a species to a fragmentation event may affect our observations of population density in post-fragmentation experiments. We found that the boundary-crossing probability from habitat to matrix, which partly determines the emigration rate, is the most important determinant for population density within habitat patches. The probability of crossing a boundary from matrix to habitat had a weaker, but positive, effect on population density. Movement behavior in habitat had a stronger effect on population density than movement behavior in matrix. Habitat fragmentation and inter-patch distance may have a positive or negative effect on population density. The direction of both effects depends on two factors. First, when the boundary-crossing probability from habitat to matrix is high, population density may decline with increasing habitat fragmentation. Conversely, for species with a high matrix-to-habitat boundary-crossing probability, population density may increase with increasing habitat fragmentation. Second, the initial distribution of individuals across the landscape: we found that habitat fragmentation and inter-patch distance were positively correlated with population density when individuals were distributed across matrix and habitat at the beginning of our simulation experiments. The direction of these relationships changed to negative when individuals were initially distributed across habitat only. Our findings imply that the speed of the initial response of organisms to habitat fragmentation events may determine the direction of observed relationships between habitat fragmentation and population density. The time scale of post

  15. 3.10. Habitat restoration and creation

    OpenAIRE

    2016-01-01

    1.12.1 Terrestrial habitat Based on the collated evidence, what is the current assessment of the effectiveness of interventions for terrestrial habitat restoration and creation? Beneficial ● Replant vegetation Likely to be beneficial ● Clear vegetation● Create artificial hibernacula or aestivation sites● Create refuges● Restore habitat connectivity Unknown effectiveness (limited evidence) ● Change mowing regime No evidence found (no assessment) ● Create habitat connectivity Beneficial Repla...

  16. Microbial ecology of Thailand tsunami and non-tsunami affected terrestrials.

    Science.gov (United States)

    Somboonna, Naraporn; Wilantho, Alisa; Jankaew, Kruawun; Assawamakin, Anunchai; Sangsrakru, Duangjai; Tangphatsornruang, Sithichoke; Tongsima, Sissades

    2014-01-01

    The effects of tsunamis on microbial ecologies have been ill-defined, especially in Phang Nga province, Thailand. This ecosystem was catastrophically impacted by the 2004 Indian Ocean tsunami as well as the 600 year-old tsunami in Phra Thong island, Phang Nga province. No study has been conducted to elucidate their effects on microbial ecology. This study represents the first to elucidate their effects on microbial ecology. We utilized metagenomics with 16S and 18S rDNA-barcoded pyrosequencing to obtain prokaryotic and eukaryotic profiles for this terrestrial site, tsunami affected (S1), as well as a parallel unaffected terrestrial site, non-tsunami affected (S2). S1 demonstrated unique microbial community patterns than S2. The dendrogram constructed using the prokaryotic profiles supported the unique S1 microbial communities. S1 contained more proportions of archaea and bacteria domains, specifically species belonging to Bacteroidetes became more frequent, in replacing of the other typical floras like Proteobacteria, Acidobacteria and Basidiomycota. Pathogenic microbes, including Acinetobacter haemolyticus, Flavobacterium spp. and Photobacterium spp., were also found frequently in S1. Furthermore, different metabolic potentials highlighted this microbial community change could impact the functional ecology of the site. Moreover, the habitat prediction based on percent of species indicators for marine, brackish, freshwater and terrestrial niches pointed the S1 to largely comprise marine habitat indicating-species.

  17. Stream microbial diversity responds to environmental changes: Review and synthesis of existing research

    Directory of Open Access Journals (Sweden)

    Lydia eZeglin

    2015-05-01

    Full Text Available The importance of microbial activity to ecosystem function in aquatic ecosystems is well established, but microbial diversity has been less frequently addressed. This review and synthesis of the hundreds of published studies on stream microbial diversity shows that factors known to drive ecosystem processes, such as nutrient availability, hydrology, metal contamination, contrasting land-use and temperature, also cause heterogeneity in bacterial diversity. Temporal heterogeneity in stream bacterial diversity was frequently observed, reflecting the dynamic nature of both stream ecosystems and microbial community composition. However, within-stream spatial differences in stream bacterial diversity were more commonly observed, driven specifically by different organic matter compartments. Bacterial phyla showed similar patterns in relative abundance with regard to compartment type across different streams. For example, surface water contained the highest relative abundance of Actinobacteria, while epilithon contained the highest relative abundance of Cyanobacteria and Bacteroidetes. This suggests that contrasting physical and/or nutritional habitats characterized by different stream organic matter compartment types may select for certain bacterial lineages. When comparing the prevalence of physicochemical effects on stream bacterial diversity, effects of changing metal concentrations were most, while effects of differences in nutrient concentrations were least frequently observed. This may indicate that although changing nutrient concentrations do tend to affect microbial diversity, other environmental factors are more likely to alter stream microbial diversity and function. The common observation of connections between ecosystem process drivers and microbial diversity suggests that microbial taxonomic turnover could mediate ecosystem-scale responses to changing environmental conditions, including both microbial habitat distribution and

  18. A technical guide for monitoring wildlife habitat

    Science.gov (United States)

    M.M. Rowland; C.D. Vojta

    2013-01-01

    Information about status and trend of wildlife habitat is important for the U.S. Department of Agriculture, Forest Service to accomplish its mission and meet its legal requirements. As the steward of 193 million acres (ac) of Federal land, the Forest Service needs to evaluate the status of wildlife habitat and how it compares with desired conditions. Habitat monitoring...

  19. Habitat preference of Roan Antelope (Hippotragus equinus ...

    African Journals Online (AJOL)

    Key words: Habitat Preference, Roan Antelope, Seasons. INTRODUCTION. Habitat quality and quantity have been identified as the primary limiting factors that influence animal population dynamics. (Jansen et al., 2001). Habitat influences the presence, abundance, distribution, movement and behavior of game animals.

  20. Creating complex habitats for restoration and reconciliation

    NARCIS (Netherlands)

    Loke, L.H.L.; Ladle, R.J.; Bouma, T.J.; Todd, P.A.

    2015-01-01

    Simplification of natural habitats has become a major conservation challenge and there is a growing consensus that incorporating and enhancing habitat complexity is likely to be critical for future restoration efforts. Habitat complexity is often ascribed an important role in controlling species

  1. 50 CFR 17.94 - Critical habitats.

    Science.gov (United States)

    2010-10-01

    ... habitats. (a) The areas listed in § 17.95 (fish and wildlife) and § 17.96 (plants) and referred to in the... physical constituent elements within the defined area of Critical Habitat that are essential to the... 50 Wildlife and Fisheries 2 2010-10-01 2010-10-01 false Critical habitats. 17.94 Section 17.94...

  2. 75 FR 34975 - Notice of Estuary Habitat Restoration Council's Intent to Revise its Estuary Habitat Restoration...

    Science.gov (United States)

    2010-06-21

    ... Estuary Habitat Restoration Council's Intent to Revise its Estuary Habitat Restoration Strategy; Request... interagency Estuary Habitat Restoration Council, is providing notice of the Council's intent to revise the ''Estuary Habitat Restoration Strategy'' and requesting public comments to guide its revision. DATES...

  3. Molecular ecology of microbial mats

    NARCIS (Netherlands)

    Bolhuis, H.; Cretoiu, M.S.; Stal, L.J.

    2014-01-01

    Phototrophic microbial mats are ideal model systems for ecological and evolutionary analysis of highly diverse microbial communities. Microbial mats are small-scale, nearly closed, and self-sustaining benthic ecosystems that comprise the major element cycles, trophic levels, and food webs. The steep

  4. Anaerobic microbial dehalogenation

    NARCIS (Netherlands)

    Smidt, H.; Vos, de W.M.

    2004-01-01

    The natural production and anthropogenic release of halogenated hydrocarbons into the environment has been the likely driving force for the evolution of an unexpectedly high microbial capacity to dehalogenate different classes of xenobiotic haloorganics. This contribution provides an update on the

  5. Diazotrophic microbial mats

    NARCIS (Netherlands)

    Severin, I.; Stal, L.J.; Seckbach, J.; Oren, A.

    2010-01-01

    Microbial mats have been the focus of scientific research for a few decades. These small-scale ecosystems are examples of versatile benthic communities of microorganisms, usually dominated by phototrophic bacteria (e.g., Krumbein et al., 1977; Jørgensen et al., 1983). They develop as vertically

  6. Microbial Energy Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, Merry [American Society for Microbiology (ASM), Washington, DC (United States); Wall, Judy D. [Univ. of Missouri, Columbia, MO (United States)

    2006-10-01

    The American Academy of Microbiology convened a colloquium March 10-12, 2006, in San Francisco, California, to discuss the production of energy fuels by microbial conversions. The status of research into various microbial energy technologies, the advantages and disadvantages of each of these approaches, research needs in the field, and education and training issues were examined, with the goal of identifying routes for producing biofuels that would both decrease the need for fossil fuels and reduce greenhouse gas emissions. Currently, the choices for providing energy are limited. Policy makers and the research community must begin to pursue a broader array of potential energy technologies. A diverse energy portfolio that includes an assortment of microbial energy choices will allow communities and consumers to select the best energy solution for their own particular needs. Funding agencies and governments alike need to prepare for future energy needs by investing both in the microbial energy technologies that work today and in the untested technologies that will serve the world’s needs tomorrow. More mature bioprocesses, such as ethanol production from starchy materials and methane from waste digestors, will find applications in the short term. However, innovative techniques for liquid fuel or biohydrogen production are among the longer term possibilities that should also be vigorously explored, starting now. Microorganisms can help meet human energy needs in any of a number of ways. In their most obvious role in energy conversion, microorganisms can generate fuels, including ethanol, hydrogen, methane, lipids, and butanol, which can be burned to produce energy. Alternatively, bacteria can be put to use in microbial fuel cells, where they carry out the direct conversion of biomass into electricity. Microorganisms may also be used some day to make oil and natural gas technologies more efficient by sequestering carbon or by assisting in the recovery of oil and

  7. Microbial electrosynthesis of biochemicals

    NARCIS (Netherlands)

    Bajracharya, S.

    2016-01-01

    Microbial electrosynthesis (MES) is an electricity-driven production of chemicals from low-value waste using microorganisms as biocatalysts. MES from CO2 comprises conversion of CO2 to multi-carbon compounds employing microbes at the cathode which use electricity as an energy source. This thesis

  8. Preparing for the crewed Mars journey: microbiota dynamics in the confined Mars500 habitat during simulated Mars flight and landing.

    Science.gov (United States)

    Schwendner, Petra; Mahnert, Alexander; Koskinen, Kaisa; Moissl-Eichinger, Christine; Barczyk, Simon; Wirth, Reinhard; Berg, Gabriele; Rettberg, Petra

    2017-10-04

    The Mars500 project was conceived as the first full duration simulation of a crewed return flight to Mars. For 520 days, six crew members lived confined in a specifically designed spacecraft mock-up. The herein described "MIcrobial ecology of Confined Habitats and humAn health" (MICHA) experiment was implemented to acquire comprehensive microbiota data from this unique, confined manned habitat, to retrieve important information on the occurring microbiota dynamics, the microbial load and diversity in the air and on various surfaces. In total, 360 samples from 20 (9 air, 11 surface) locations were taken at 18 time-points and processed by extensive cultivation, PhyloChip and next generation sequencing (NGS) of 16S rRNA gene amplicons. Cultivation assays revealed a Staphylococcus and Bacillus-dominated microbial community on various surfaces, with an average microbial load that did not exceed the allowed limits for ISS in-flight requirements indicating adequate maintenance of the facility. Areas with high human activity were identified as hotspots for microbial accumulation. Despite substantial fluctuation with respect to microbial diversity and abundance throughout the experiment, the location within the facility and the confinement duration were identified as factors significantly shaping the microbial diversity and composition, with the crew representing the main source for microbial dispersal. Opportunistic pathogens, stress-tolerant or potentially mobile element-bearing microorganisms were predicted to be prevalent throughout the confinement, while the overall microbial diversity dropped significantly over time. Our findings clearly indicate that under confined conditions, the community structure remains a highly dynamic system which adapts to the prevailing habitat and micro-conditions. Since a sterile environment is not achievable, these dynamics need to be monitored to avoid spreading of highly resistant or potentially pathogenic microorganisms and a

  9. An approach of habitat degradation assessment for characterization on coastal habitat conservation tendency.

    Science.gov (United States)

    Zhou, Xi-Yin; Lei, Kun; Meng, Wei

    2017-09-01

    Coastal zones are population and economy highly intensity regions all over the world, and coastal habitat supports the sustainable development of human society. The accurate assessment of coastal habitat degradation is the essential prerequisite for coastal zone protection. In this study, an integrated framework of coastal habitat degradation assessment including landuse classification, habitat classifying and zoning, evaluation criterion of coastal habitat degradation and coastal habitat degradation index has been established for better regional coastal habitat assessment. Through establishment of detailed three-class landuse classification, the fine landscape change is revealed, the evaluation criterion of coastal habitat degradation through internal comparison based on the results of habitat classifying and zoning could indicate the levels of habitat degradation and distinguish the intensity of human disturbances in different habitat subareas under the same habitat classification. Finally, the results of coastal habitat degradation assessment could be achieved through coastal habitat degradation index (CHI). A case study of the framework is carried out in the Circum-Bohai-Sea-Coast, China, and the main results show the following: (1) The accuracy of all land use classes are above 90%, which indicates a satisfactory accuracy for the classification map. (2) The Circum-Bohai-Sea-Coast is divided into 3 kinds of habitats and 5 subareas. (3) In the five subareas of the Circum-Bohai-Sea-Coast, the levels of coastal habitat degradation own significant difference. The whole Circum-Bohai-Sea-Coast generally is in a worse state according to area weighting of each habitat subarea. This assessment framework of coastal habitat degradation would characterize the landuse change trend, realize better coastal habitat degradation assessment, reveal the habitat conservation tendency and distinguish intensity of human disturbances. Furthermore, it would support for accurate coastal

  10. Modelling Fish Habitat Suitability in the Eastern English Channel. Application to community habitat level

    OpenAIRE

    Vaz, Sandrine; Carpentier, Andre; Loots, Christophe; Koubbi, Philippe

    2004-01-01

    Valuable marine habitats and living resources can be found in the Eastern English Channel and in 2003, a Franco-British Interreg IIIA project, ‘Eastern Channel Habitat Atlas for Marine Resource Management’ (CHARM), was initiated to support decision-making for management of essential fish habitats. Fish habitat corresponds to geographic areas within which ranges of environmental factors define the presence of a particular species. Habitat Suitability index (HSI) modelling was used to relate fi...

  11. Microbial uptake of uranium, cesium, and radium

    Energy Technology Data Exchange (ETDEWEB)

    Strandberg, G.W.; Shumate, S.E. II; Parrott, J.R. Jr.; McWhirter, D.A.

    1980-01-01

    The ability of diverse microbial species to concentrate uranium, cesium, and radium was examined. Saccharomyces cerevisiae, Pseudomonas aeruginosa, and a mixed culture of denitrifying bacteria accumulated uranium to 10 to 15% of the dry cell weight. Only a fraction of the cells in a given population had visible uranium deposits in electron micrographs. While metabolism was not required for uranium uptake, mechanistic differences in the metal uptake process were indicated. Uranium accumulated slowly (hours) on the surface of S. cerevisiae and was subject to environmental factors (i.e., temperature, pH, interfering cations and anions). In contrast, P. aeruginosa and the mixed culture of denitrifying bacteria accumulated uranium rapidly (minutes) as dense, apparently random, intracellular deposits. This very rapid accumulation has prevented us from determining whether the uptake rate during the transient between the initial and equilibrium distribution of uranium is affected by environmental conditions. However, the final equilibrium distributions are not affected by those conditions which affect uptake by S. cerevisiae. Cesium and radium were concentrated to a considerably lesser extent than uranium by the several microbial species tested. The potential utility of microorganisms for the removal and concentration of these metals from nuclear processing wastes and several bioreactor designs for contacting microorganisms with contaminated waste streams will be discussed.

  12. Transient hyperthyroidism of hyperemesis gravidarum.

    Science.gov (United States)

    Tan, Jackie Y L; Loh, Keh Chuan; Yeo, George S H; Chee, Yam Cheng

    2002-06-01

    To characterise the clinical, biochemical and thyroid antibody profile in women with transient hyperthyroidism of hyperemesis gravidarum. Prospective observational study. Hospital inpatient gynaecological ward. Women admitted with hyperemesis gravidarum and found to have hyperthyroidism. Fifty-three women were admitted with hyperemesis gravidarum and were found to have hyperthyroidism. Each woman was examined for clinical signs of thyroid disease and underwent investigations including urea, creatinine, electrolytes, liver function test, thyroid antibody profile and serial thyroid function test until normalisation. Gestation at which thyroid function normalised, clinical and thyroid antibody profile and pregnancy outcome (birthweight, gestation at delivery and Apgar score at 5 minutes). Full data were available for 44 women. Free T4 levels normalised by 15 weeks of gestation in the 39 women with transient hyperthyroidism while TSH remained suppressed until 19 weeks of gestation. None of these women were clinically hyperthyroid. Thyroid antibodies were not found in most of them. Median birthweight in the infants of mothers who experienced weight loss of > 5% of their pre-pregnancy weight was lower compared with those of women who did not (P = 0.093). Five women were diagnosed with Graves' disease based on clinical features and thyroid antibody profile. In transient hyperthyroidism of hyperemesis gravidarum, thyroid function normalises by the middle of the second trimester without anti-thyroid treatment. Clinically overt hyperthyroidism and thyroid antibodies are usually absent. Apart from a non-significant trend towards lower birthweights in the infants of mothers who experienced significant weight loss, pregnancy outcome was generally good. Routine assessment of thyroid function is unnecessary for women with hyperemesis gravidarum in the absence of any clinical features of hyperthyroidism.

  13. Microbial mutualism at a distance: The role of geometry in diffusive exchanges

    Science.gov (United States)

    Peaudecerf, François J.; Bunbury, Freddy; Bhardwaj, Vaibhav; Bees, Martin A.; Smith, Alison G.; Goldstein, Raymond E.; Croze, Ottavio A.

    2018-02-01

    The exchange of diffusive metabolites is known to control the spatial patterns formed by microbial populations, as revealed by recent studies in the laboratory. However, the matrices used, such as agarose pads, lack the structured geometry of many natural microbial habitats, including in the soil or on the surfaces of plants or animals. Here we address the important question of how such geometry may control diffusive exchanges and microbial interaction. We model mathematically mutualistic interactions within a minimal unit of structure: two growing reservoirs linked by a diffusive channel through which metabolites are exchanged. The model is applied to study a synthetic mutualism, experimentally parametrized on a model algal-bacterial co-culture. Analytical and numerical solutions of the model predict conditions for the successful establishment of remote mutualisms, and how this depends, often counterintuitively, on diffusion geometry. We connect our findings to understanding complex behavior in synthetic and naturally occurring microbial communities.

  14. Sediment Microbial Communities Influenced by Cool Hydrothermal Fluid Migration

    Directory of Open Access Journals (Sweden)

    Laura A. Zinke

    2018-06-01

    Full Text Available Cool hydrothermal systems (CHSs are prevalent across the seafloor and discharge fluid volumes that rival oceanic input from rivers, yet the microbial ecology of these systems are poorly constrained. The Dorado Outcrop on the ridge flank of the Cocos Plate in the northeastern tropical Pacific Ocean is the first confirmed CHS, discharging minimally altered <15°C fluid from the shallow lithosphere through diffuse venting and seepage. In this paper, we characterize the resident sediment microbial communities influenced by cool hydrothermal advection, which is evident from nitrate and oxygen concentrations. 16S rRNA gene sequencing revealed that Thaumarchaea, Proteobacteria, and Planctomycetes were the most abundant phyla in all sediments across the system regardless of influence from seepage. Members of the Thaumarchaeota (Marine Group I, Alphaproteobacteria (Rhodospirillales, Nitrospirae, Nitrospina, Acidobacteria, and Gemmatimonadetes were enriched in the sediments influenced by CHS advection. Of the various geochemical parameters investigated, nitrate concentrations correlated best with microbial community structure, indicating structuring based on seepage of nitrate-rich fluids. A comparison of microbial communities from hydrothermal sediments, seafloor basalts, and local seawater at Dorado Outcrop showed differences that highlight the distinct niche space in CHS. Sediment microbial communities from Dorado Outcrop differ from those at previously characterized, warmer CHS sediment, but are similar to deep-sea sediment habitats with surficial ferromanganese nodules, such as the Clarion Clipperton Zone. We conclude that cool hydrothermal venting at seafloor outcrops can alter the local sedimentary oxidation–reduction pathways, which in turn influences the microbial communities within the fluid discharge affected sediment.

  15. The course of transient hypochondriasis.

    Science.gov (United States)

    Barsky, A J; Cleary, P D; Sarnie, M K; Klerman, G L

    1993-03-01

    This study examined the longitudinal course of patients known to have had a previous episode of transient hypochondriasis. Twenty-two transiently hypochondriacal patients and 24 nonhypochondriacal patients from the same general medical clinic were reexamined after an average of 22 months with the use of self-report questionnaires, structured diagnostic interviews, and medical record review. The hypochondriacal patients continued to manifest significantly more hypochondriacal symptoms, more somatization, and more psychopathological symptoms at follow-up. They also reported significantly more amplification of bodily sensations and more functional disability and utilized more medical care. These differences persisted after control for differences in medical morbidity and marital status. Only one hypochondriacal patient, however, had a DSM-III-R diagnosis of hypochondriasis at follow-up. Multivariate analyses revealed that the only significant predictors of hypochondriacal symptoms at follow-up were hypochondriacal symptoms and the tendency to amplify bodily sensations at the baseline evaluation. Hypochondriacal symptoms appear to have some temporal stability: patients who experienced hypochondriacal episodes at the beginning of the study were significantly more hypochondriacal 2 years later than comparison patients. They were not, however, any more likely to develop DSM-III-R-defined hypochondriasis. Thus, hypochondriacal symptoms may be distinct from the axis I disorder. The data are also compatible with the hypothesis that preexisting amplification of bodily sensations is an important predictor of subsequent hypochondriacal symptoms.

  16. Transient global amnesia: current perspectives

    Directory of Open Access Journals (Sweden)

    Spiegel DR

    2017-10-01

    Full Text Available David R Spiegel, Justin Smith, Ryan R Wade, Nithya Cherukuru, Aneel Ursani, Yuliya Dobruskina, Taylor Crist, Robert F Busch, Rahim M Dhanani, Nicholas Dreyer Department of Psychiatry and Behavioral Sciences, Eastern Virginia Medical School, Norfolk, VA, USA Abstract: Transient global amnesia (TGA is a clinical syndrome characterized by the sudden onset of an extraordinarily large reduction of anterograde and a somewhat milder reduction of retrograde episodic long-term memory. Additionally, executive functions are described as diminished. Although it is suggested that various factors, such as migraine, focal ischemia, venous flow abnormalities, and epileptic phenomena, are involved in the pathophysiology and differential diagnosis of TGA, the factors triggering the emergence of these lesions are still elusive. Recent data suggest that the vulnerability of CA1 neurons to metabolic stress plays a pivotal part in the pathophysiological cascade, leading to an impairment of hippocampal function during TGA. In this review, we discuss clinical aspects, new imaging findings, and recent clinical–epidemiological data with regard to the phenotype, functional anatomy, and putative cellular mechanisms of TGA. Keywords: transient global amnesia, vascular, migraines, psychiatric

  17. Transient trimethylaminuria related to menstruation

    Science.gov (United States)

    Shimizu, Makiko; Cashman, John R; Yamazaki, Hiroshi

    2007-01-01

    Background Trimethylaminuria, or fish odor syndrome, includes a transient or mild malodor caused by an excessive amount of malodorous trimethylamine as a result of body secretions. Herein, we describe data to support the proposal that menses can be an additional factor causing transient trimethylaminuria in self-reported subjects suffering from malodor and even in healthy women harboring functionally active flavin-containing monooxygenase 3 (FMO3). Methods FMO3 metabolic capacity (conversion of trimethylamine to trimethylamine N-oxide) was defined as the urinary ratio of trimethylamine N-oxide to total trimethylamine. Results Self-reported Case (A) that was homozygous for inactive Arg500stop FMO3, showed decreased metabolic capacity of FMO3 (i.e., ~10% the unaffected metabolic capacity) during 120 days of observation. For Case (B) that was homozygous for common [Glu158Lys; Glu308Gly] FMO3 polymorphisms, metabolic capacity of FMO3 was almost ~90%, except for a few days surrounding menstruation showing 90%) metabolic capacity, however, on days around menstruation the FMO3 metabolic capacity was decreased to ~60–70%. Conclusion Together, these results indicate that abnormal FMO3 capacity is caused by menstruation particularly in the presence, in homozygous form, of mild genetic variants such as [Glu158Lys; Glu308Gly] that cause a reduced FMO3 function. PMID:17257434

  18. Prismatic Core Coupled Transient Benchmark

    International Nuclear Information System (INIS)

    Ortensi, J.; Pope, M.A.; Strydom, G.; Sen, R.S.; DeHart, M.D.; Gougar, H.D.; Ellis, C.; Baxter, A.; Seker, V.; Downar, T.J.; Vierow, K.; Ivanov, K.

    2011-01-01

    The Prismatic Modular Reactor (PMR) is one of the High Temperature Reactor (HTR) design concepts that have existed for some time. Several prismatic units have operated in the world (DRAGON, Fort St. Vrain, Peach Bottom) and one unit is still in operation (HTTR). The deterministic neutronics and thermal-fluids transient analysis tools and methods currently available for the design and analysis of PMRs have lagged behind the state of the art compared to LWR reactor technologies. This has motivated the development of more accurate and efficient tools for the design and safety evaluations of the PMR. In addition to the work invested in new methods, it is essential to develop appropriate benchmarks to verify and validate the new methods in computer codes. The purpose of this benchmark is to establish a well-defined problem, based on a common given set of data, to compare methods and tools in core simulation and thermal hydraulics analysis with a specific focus on transient events. The benchmark-working group is currently seeking OECD/NEA sponsorship. This benchmark is being pursued and is heavily based on the success of the PBMR-400 exercise.

  19. Habitat Management: A Tool to Modify Ecosystem Impacts of Nitrogen Deposition?

    Directory of Open Access Journals (Sweden)

    S.A. Power

    2001-01-01

    Full Text Available Atmospheric nitrogen deposition has been shown to affect both the structure and the function of heathland ecosystems. Heathlands are semi-natural habitats and, as such, undergo regular management by mowing or burning. Different forms of management remove more or less nutrients from the system, so habitat management has the potential to mitigate some of the effects of atmospheric deposition. Data from a dynamic vegetation model and two field experiments are presented. The first involves nitrogen addition following different forms of habitat management. The second tests the use of habitat management to promote heathland recovery after a reduction in nitrogen deposition. Both modelling and experimental approaches suggest that plant and microbial response to nitrogen is affected by management. Shoot growth and rates of decomposition were lowest in plots managed using more intensive techniques, including mowing with litter removal and a high temperature burn. Field data also indicate that ecosystem recovery from prolonged elevated inputs of nitrogen may take many years, or even decades, even after the removal of plant and litter nitrogen stores which accompanies the more intensive forms of habitat management.

  20. Rumen microbial genomics

    International Nuclear Information System (INIS)

    Morrison, M.; Nelson, K.E.

    2005-01-01

    Improving microbial degradation of plant cell wall polysaccharides remains one of the highest priority goals for all livestock enterprises, including the cattle herds and draught animals of developing countries. The North American Consortium for Genomics of Fibrolytic Ruminal Bacteria was created to promote the sequencing and comparative analysis of rumen microbial genomes, offering the potential to fully assess the genetic potential in a functional and comparative fashion. It has been found that the Fibrobacter succinogenes genome encodes many more endoglucanases and cellodextrinases than previously isolated, and several new processive endoglucanases have been identified by genome and proteomic analysis of Ruminococcus albus, in addition to a variety of strategies for its adhesion to fibre. The ramifications of acquiring genome sequence data for rumen microorganisms are profound, including the potential to elucidate and overcome the biochemical, ecological or physiological processes that are rate limiting for ruminal fibre degradation. (author)

  1. Microbial Genomes Multiply

    Science.gov (United States)

    Doolittle, Russell F.

    2002-01-01

    The publication of the first complete sequence of a bacterial genome in 1995 was a signal event, underscored by the fact that the article has been cited more than 2,100 times during the intervening seven years. It was a marvelous technical achievement, made possible by automatic DNA-sequencing machines. The feat is the more impressive in that complete genome sequencing has now been adopted in many different laboratories around the world. Four years ago in these columns I examined the situation after a dozen microbial genomes had been completed. Now, with upwards of 60 microbial genome sequences determined and twice that many in progress, it seems reasonable to assess just what is being learned. Are new concepts emerging about how cells work? Have there been practical benefits in the fields of medicine and agriculture? Is it feasible to determine the genomic sequence of every bacterial species on Earth? The answers to these questions maybe Yes, Perhaps, and No, respectively.

  2. Degradation of microbial polyesters.

    Science.gov (United States)

    Tokiwa, Yutaka; Calabia, Buenaventurada P

    2004-08-01

    Microbial polyhydroxyalkanoates (PHAs), one of the largest groups of thermoplastic polyesters are receiving much attention as biodegradable substitutes for non-degradable plastics. Poly(D-3-hydroxybutyrate) (PHB) is the most ubiquitous and most intensively studied PHA. Microorganisms degrading these polyesters are widely distributed in various environments. Although various PHB-degrading microorganisms and PHB depolymerases have been studied and characterized, there are still many groups of microorganisms and enzymes with varying properties awaiting various applications. Distributions of PHB-degrading microorganisms, factors affecting the biodegradability of PHB, and microbial and enzymatic degradation of PHB are discussed in this review. We also propose an application of a new isolated, thermophilic PHB-degrading microorganism, Streptomyces strain MG, for producing pure monomers of PHA and useful chemicals, including D-3-hydroxycarboxylic acids such as D-3-hydroxybutyric acid, by enzymatic degradation of PHB.

  3. Global Microbial Identifier

    DEFF Research Database (Denmark)

    Wielinga, Peter; Hendriksen, Rene S.; Aarestrup, Frank Møller

    2017-01-01

    ) will likely also enable a much better understanding of the pathogenesis of the infection and the molecular basis of the host response to infection. But the full potential of these advances will only transpire if the data in this area become transferable and thereby comparable, preferably in open-source...... of microorganisms, for the identification of relevant genes and for the comparison of genomes to detect outbreaks and emerging pathogens. To harness the full potential of WGS, a shared global database of genomes linked to relevant metadata and the necessary software tools needs to be generated, hence the global...... microbial identifier (GMI) initiative. This tool will ideally be used in amongst others in the diagnosis of infectious diseases in humans and animals, in the identification of microorganisms in food and environment, and to track and trace microbial agents in all arenas globally. This will require...

  4. Life in the "plastisphere": microbial communities on plastic marine debris.

    Science.gov (United States)

    Zettler, Erik R; Mincer, Tracy J; Amaral-Zettler, Linda A

    2013-07-02

    Plastics are the most abundant form of marine debris, with global production rising and documented impacts in some marine environments, but the influence of plastic on open ocean ecosystems is poorly understood, particularly for microbial communities. Plastic marine debris (PMD) collected at multiple locations in the North Atlantic was analyzed with scanning electron microscopy (SEM) and next-generation sequencing to characterize the attached microbial communities. We unveiled a diverse microbial community of heterotrophs, autotrophs, predators, and symbionts, a community we refer to as the "Plastisphere". Pits visualized in the PMD surface conformed to bacterial shapes suggesting active hydrolysis of the hydrocarbon polymer. Small-subunit rRNA gene surveys identified several hydrocarbon-degrading bacteria, supporting the possibility that microbes play a role in degrading PMD. Some Plastisphere members may be opportunistic pathogens (the authors, unpublished data) such as specific members of the genus Vibrio that dominated one of our plastic samples. Plastisphere communities are distinct from surrounding surface water, implying that plastic serves as a novel ecological habitat in the open ocean. Plastic has a longer half-life than most natural floating marine substrates, and a hydrophobic surface that promotes microbial colonization and biofilm formation, differing from autochthonous substrates in the upper layers of the ocean.

  5. Identifying Pelagic Habitat Hotspots of Neon Flying Squid in the Temperate Waters of the Central North Pacific.

    Science.gov (United States)

    Alabia, Irene D; Saitoh, Sei-Ichi; Mugo, Robinson; Igarashi, Hiromichi; Ishikawa, Yoichi; Usui, Norihisa; Kamachi, Masafumi; Awaji, Toshiyuki; Seito, Masaki

    2015-01-01

    We identified the pelagic habitat hotspots of the neon flying squid (Ommastrephes bartramii) in the central North Pacific from May to July and characterized the spatial patterns of squid aggregations in relation to oceanographic features such as mesoscale oceanic eddies and the Transition Zone Chlorophyll-a Front (TZCF). The data used for the habitat model construction and analyses were squid fishery information, remotely-sensed and numerical model-derived environmental data from May to July 1999-2010. Squid habitat hotspots were deduced from the monthly Maximum Entropy (MaxEnt) models and were identified as regions of persistent high suitable habitat across the 12-year period. The distribution of predicted squid habitat hotspots in central North Pacific revealed interesting spatial and temporal patterns likely linked with the presence and dynamics of oceanographic features in squid's putative foraging grounds from late spring to summer. From May to June, the inferred patches of squid habitat hotspots developed within the Kuroshio-Oyashio transition zone (KOTZ; 37-40°N) and further expanded north towards the subarctic frontal zone (SAFZ; 40-44°N) in July. The squid habitat hotspots within the KOTZ and areas west of the dateline (160°W-180°) were likely influenced and associated with the highly dynamic and transient oceanic eddies and could possibly account for lower squid suitable habitat persistence obtained from these regions. However, predicted squid habitat hotspots located in regions east of the dateline (180°-160°W) from June to July, showed predominantly higher squid habitat persistence presumably due to their proximity to the mean position of the seasonally-shifting TZCF and consequent utilization of the highly productive waters of the SAFZ.

  6. Competition and niche separation of pelagic bacteria in freshwater habitats.

    Science.gov (United States)

    Pernthaler, Jakob

    2017-06-01

    Freshwater bacterioplankton assemblages are composed of sympatric populations that can be delineated, for example, by ribosomal RNA gene relatedness and that differ in key ecophysiological properties. They may be free-living or attached, specialized for particular concentrations or subsets of substrates, or invest a variable amount of their resources in defence traits against protistan predators and viruses. Some may be motile and tactic whereas others are not, with far-reaching implications for their respective life styles and niche partitioning. The co-occurrence of competitors with overlapping growth requirements has profound consequences for the stability of community functions; it can to some extent be explained by habitat factors such as the microscale complexity and spatiotemporal variability of the lacustrine environments. On the other hand, the composition and diversity of freshwater microbial assemblages also reflects non-equilibrium states, dispersal and the stochasticity of community assembly processes. This review synoptically discusses the competition and niche separation of heterotrophic bacterial populations (defined at various levels of phylogenetic resolution) in the pelagic zone of inland surface waters from a variety of angles, focusing on habitat heterogeneity and the resulting biogeographic distribution patterns, the ecophysiological adaptations to the substrate field and the interactions of prokaryotes with predators and viruses. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  7. A COMETHE version with transient capability

    International Nuclear Information System (INIS)

    Vliet, J. van; Lebon, G.; Mathieu, P.

    1980-01-01

    A version of the COMETHE code is under development to simulate transient situations. This paper focuses on some aspects of the transient heat transfer models. Initially the coupling between transient heat transfer and other thermomechanical models is discussed. An estimation of the thermal characteristic times shows that the cladding temperatures are often in quasi-steady state. In order to reduce the computing time, calculations are therefore switched from a transient to a quasi-static numerical procedure as soon as such a quasi-equilibrium is detected. The temperature calculation is performed by use of the Lebon-Lambermont restricted variational principle, with piecewise polynoms as trial functions. The method has been checked by comparison with some exact results and yields good agreement for transient as well as for quasi-static situations. This method therefore provides a valuable tool for the simulation of the transient behaviour of nuclear reactor fuel rods. (orig.)

  8. Experience with transients in German NPPs

    International Nuclear Information System (INIS)

    Lindauer, E.

    1984-01-01

    This chapter examines reactor accidents in the Federal Republic of Germany based on the formal reporting system for licensee event reports (LERs) and a special investigation on all unplanned power variations in 3 PWRs. The significant transients experienced by BWR type reactors are analyzed. The main goal is to find weak points which caused the transient or influenced its course in an unfavorable way in order to improve the affected plant and others. The complete survey of all transients, with normally little or no safety relevance, allows statistical evaluations and the analysis of trends. It is concluded that significant transients were mainly experienced at older plants, whereas plants of an advanced design produced very few significant transients. The most frequent human errors which lead to transients are failure search in electronic systems and errors during design and commissioning

  9. Synthetic microbial ecology and the dynamic interplay between microbial genotypes.

    Science.gov (United States)

    Dolinšek, Jan; Goldschmidt, Felix; Johnson, David R

    2016-11-01

    Assemblages of microbial genotypes growing together can display surprisingly complex and unexpected dynamics and result in community-level functions and behaviors that are not readily expected from analyzing each genotype in isolation. This complexity has, at least in part, inspired a discipline of synthetic microbial ecology. Synthetic microbial ecology focuses on designing, building and analyzing the dynamic behavior of ‘ecological circuits’ (i.e. a set of interacting microbial genotypes) and understanding how community-level properties emerge as a consequence of those interactions. In this review, we discuss typical objectives of synthetic microbial ecology and the main advantages and rationales of using synthetic microbial assemblages. We then summarize recent findings of current synthetic microbial ecology investigations. In particular, we focus on the causes and consequences of the interplay between different microbial genotypes and illustrate how simple interactions can create complex dynamics and promote unexpected community-level properties. We finally propose that distinguishing between active and passive interactions and accounting for the pervasiveness of competition can improve existing frameworks for designing and predicting the dynamics of microbial assemblages.

  10. Transient analysis for resolving safety issues

    International Nuclear Information System (INIS)

    Chao, J.; Layman, W.

    1987-01-01

    The Nuclear Safety Analysis Center (NSAC) has a Generic Safety Analysis Program to help resolve high priority generic safety issues. This paper describes several high priority safety issues considered at NSAC and how they were resolved by transient analysis using thermal hydraulics and neutronics codes. These issues are pressurized thermal shock (PTS), anticipated transients without scram (ATWS), steam generator tube rupture (SGTR), and reactivity transients in light of the Chernobyl accident

  11. Analysis of transient signals by Wavelet transform

    International Nuclear Information System (INIS)

    Penha, Rosani Libardi da; Silva, Aucyone A. da; Ting, Daniel K.S.; Oliveira Neto, Jose Messias de

    2000-01-01

    The objective of this work is to apply the Wavelet Transform in transient signals. The Wavelet technique can outline the short time events that are not easily detected using traditional techniques. In this work, the Wavelet Transform is compared with Fourier Transform, by using simulated data and rotor rig data. This data contain known transients. The wavelet could follow all the transients, what do not happen to the Fourier techniques. (author)

  12. Instrument response during overpower transients at TREAT

    International Nuclear Information System (INIS)

    Meek, C.C.; Bauer, T.H.; Hill, D.J.; Froehle, P.H.; Klickman, A.E.; Tylka, J.P.; Doerner, R.C.; Wright, A.E.

    1982-01-01

    A program to empirically analyze data residuals or noise to determine instrument response that occurs during in-pile transient tests is out-lined. As an example, thermocouple response in the Mark III loop during a severe overpower transient in TREAT is studied both in frequency space and in real-time. Time intervals studied included both constant power and burst portions of the power transient. Thermocouple time constants were computed. Benefits and limitations of the method are discussed

  13. OPTICAL TRANSIENT DETECTOR (OTD) LIGHTNING V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Optical Transient Detector (OTD) records optical measurements of global lightning events in the daytime and nighttime. The data includes individual point...

  14. Influence of prevailing disturbances on soil biology and biochemistry of montane habitats at Nanda Devi Biosphere Reserve, India during wet and dry seasons

    DEFF Research Database (Denmark)

    Singh, S.K.; Singh, Anoop; Rai, J.P.N.

    2011-01-01

    The impact of prevailing disturbances in montane habitats of Nanda Devi Biosphere Reserve (NDBR) was studied on soil microbial population, biomass, soil respiration and enzyme activities during wet and dry seasons. The physico-chemical characteristics of soils exhibited conspicuous variation in t...

  15. The role of macrobiota in structuring microbial communities along rocky shores

    Directory of Open Access Journals (Sweden)

    Catherine A. Pfister

    2014-10-01

    Full Text Available Rocky shore microbial diversity presents an excellent system to test for microbial habitat specificity or generality, enabling us to decipher how common macrobiota shape microbial community structure. At two coastal locations in the northeast Pacific Ocean, we show that microbial composition was significantly different between inert surfaces, the biogenic surfaces that included rocky shore animals and an alga, and the water column plankton. While all sampled entities had a core of common OTUs, rare OTUs drove differences among biotic and abiotic substrates. For the mussel Mytilus californianus, the shell surface harbored greater alpha diversity compared to internal tissues of the gill and siphon. Strikingly, a 7-year experimental removal of this mussel from tidepools did not significantly alter the microbial community structure of microbes associated with inert surfaces when compared with unmanipulated tidepools. However, bacterial taxa associated with nitrate reduction had greater relative abundance with mussels present, suggesting an impact of increased animal-derived nitrogen on a subset of microbial metabolism. Because the presence of mussels did not affect the structure and diversity of the microbial community on adjacent inert substrates, microbes in this rocky shore environment may be predominantly affected through direct physical association with macrobiota.

  16. Reprint of Design of synthetic microbial communities for biotechnological production processes.

    Science.gov (United States)

    Jagmann, Nina; Philipp, Bodo

    2014-12-20

    In their natural habitats microorganisms live in multi-species communities, in which the community members exhibit complex metabolic interactions. In contrast, biotechnological production processes catalyzed by microorganisms are usually carried out with single strains in pure cultures. A number of production processes, however, may be more efficiently catalyzed by the concerted action of microbial communities. This review will give an overview of organismic interactions between microbial cells and of biotechnological applications of microbial communities. It focuses on synthetic microbial communities that consist of microorganisms that have been genetically engineered. Design principles for such synthetic communities will be exemplified based on plausible scenarios for biotechnological production processes. These design principles comprise interspecific metabolic interactions via cross-feeding, regulation by interspecific signaling processes via metabolites and autoinducing signal molecules, and spatial structuring of synthetic microbial communities. In particular, the implementation of metabolic interdependencies, of positive feedback regulation and of inducible cell aggregation and biofilm formation will be outlined. Synthetic microbial communities constitute a viable extension of the biotechnological application of metabolically engineered single strains and enlarge the scope of microbial production processes. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Transient shielded liquid hydrogen containers

    International Nuclear Information System (INIS)

    Varghese, A.P.; Herring, R.H.

    1990-01-01

    The storage of hydrogen in the liquid phase has been limited in duration due to the thermal performance constraints of conventional Liquid Hydrogen containers available. Conventional Liquid Hydrogen containers lose hydrogen because of their relatively high heat leak and variations in usage pattern of hydrogen due to shutdowns. Local regulations also discourage venting of hydrogen. Long term storage of Liquid Hydrogen without product loss was usually accomplished using Liquid Nitrogen sacrificial shields. This paper reports on a new low heat leak container developed and patented that will extend the storage time of liquid hydrogen by five hundred percent. The principle of operation of the Transient Shields which makes the extraordinary performance of this container feasible is described in this paper. Also covered are the impact of this new container on present applications of hydrogen and the new opportunities afforded to Liquid hydrogen in the world hydrogen market

  18. Transient ischemic attack: diagnostic evaluation.

    Science.gov (United States)

    Messé, Steven R; Jauch, Edward C

    2008-08-01

    A transient ischemic attack portends significant risk of a stroke. Consequently, the diagnostic evaluation in the emergency department is focused on identifying high-risk causes so that preventive strategies can be implemented. The evaluation consists of a facilitated evaluation of the patient's metabolic, cardiac, and neurovascular systems. At a minimum, the following tests are recommended: fingerstick glucose level, electrolyte levels, CBC count, urinalysis, and coagulation studies; noncontrast computed tomography (CT) of the head; electrocardiography; and continuous telemetry monitoring. Vascular imaging studies, such as carotid ultrasonography, CT angiography, or magnetic resonance angiography, should be performed on an urgent basis and prioritized according to the patient's risk stratification for disease. Consideration should be given for echocardiography if no large vessel abnormality is identified.

  19. Measurement of fast transient pressures

    International Nuclear Information System (INIS)

    Procaccia, Henri

    1978-01-01

    The accuracy, reliability and sensitivity of a pressure transducers define its principal static characteristics. When the quantity measured varies with time, the measurement carries a dynamic error and a delay depending on the frequency of this variation. Hence, when fast pressure changes in a fluid have to be determined, different kinds of pressure transducers can be used depending on their inherent dynamic characteristics which must be compared with those of the transient phenomenon to be analysed. The text describes the pressure transducers generally employed in industry for analysing such phenomenon and gives two practical applications developed in the EDF: the first submits the measurements and results of pump cavitation tests carried out at the Vitry II EDF power station; the second deals with hammer blows particularly noticed in nuclear power stations and required the use of transducers of exceptionally high performance such as strain gauge transducers and piezoelectric transducers (response time within 1m sec.) [fr

  20. Ground beetle habitat templets and riverbank integrity

    OpenAIRE

    Van Looy, Kris; Vanacker, Stijn; Jochems, Hans; De Blust, Geert; Dufrêne, M

    2006-01-01

    The habitat templet approach was used in a scale-sensitive bioindicator assessment for the ecological integrity of riverbanks and for specific responses to river management. Ground beetle habitat templets were derived from a catchment scale sampling, integrating the overall variety of bank types. This coarse-filter analysis was integrated in the reach scale fine-filtering approaches of community responses to habitat integrity and river management impacts. Higher species diversity was associat...

  1. Transient photoconductivity in amorphous semiconductors

    International Nuclear Information System (INIS)

    Mpawenayo, P.

    1997-07-01

    Localized states in amorphous semiconductors are divided in disorder induced shallow trap levels and dangling bonds deep states. Dangling bonds are assumed here to be either neutral or charged and their energy distribution is a single gaussian. Here, it is shown analytically that transient photocurrent in amorphous semiconductors is fully controlled by charge carriers transitions between localized states for one part and tunneling hopping carriers on the other. Localized dangling bonds deep states act as non radiative recombination centres, while hopping tunnelling is assisted by the Coulomb interaction between defects sites. The half-width of defects distribution is the disorder parameter that determines the carrier hopping time between defects sites. The macroscopic time that explains the long decay response times observed will all types of amorphous semiconductors is duly thought to be temperature dependent. Basic equations developed by Longeaud and Kleider are solved for the general case of a semiconductor after photo-generation. It turns out that the transient photoconductivity decay has two components; one with short response times from carriers trap-release transitions between shallow levels and extended states and a hopping component made of inter-dependent exponentials whose time constants span in larger ranges depending on disorder. The photoconductivity hopping component appears as an additional term to be added to photocurrents derived from existing models. The results of the present study explain and complete the power law decay derived in the multiple trapping models developed 20 years ago only in the approximation of the short response time regime. The long response time regime is described by the hopping macroscopic time. The present model is verified for all samples of amorphous semiconductors known so far. Finally, it is proposed to improved the modulated photoconductivity calculation techniques by including the long-lasting hopping dark documents

  2. Shifts in coastal sediment oxygenation cause pronounced changes in microbial community composition and associated metabolism

    DEFF Research Database (Denmark)

    Broman, Elias; Sjöstedt, Johanna; Pinhassi, Jarone

    2017-01-01

    . In particular, the intermediate site sediments responded differently upon oxygenation compared to the anoxic and oxic site sediments. This included a microbial community composition with more habitat generalists, lower amounts of RNA transcripts attributed to methane oxidation, and a reduced rate of organic...... efforts, depend largely on the oxygenation history of sites. Furthermore, it was shown that re-oxygenation efforts to remediate dead zones could ultimately be facilitated by in situ microbial molecular mechanisms involved in removal of toxic H2S and the potent greenhouse gas methane....

  3. Exploring ancient microbial community assemblages by creating complex lipid biomarker profiles for stromatolites and microbial mats in Hamelin Pool, Shark Bay, Australia

    Science.gov (United States)

    Myers, E.; Summons, R. E.; Schubotz, F.; Matys, E. D.

    2015-12-01

    Stromatolites that are biogenic in origin, a characteristic that can be determined by the coexistence of microbial mats (active microbial communities) and stromatolites (lithified structures) like in Hamelin Pool, comprise one of the best modern analogs to ancient microbial community assemblages. Comprehensive lipid biomarker profiles that include lipids of varying persistence in the rock record can help determine how previously living microbial communities are represented in lithified stromatolites. To create these profiles, the samples analyzed included non-lithified smooth, pustular, and colloform microbial mats, as well as smooth and colloform stromatolites. Select samples were separated into upper and lower layers of 5cm depth each. Intact polar lipids, glycerol dialkyl glycerol tetraethers, and bacteriohopanepolyols were analyzed via liquid chromatography-mass spectrometry (LC-MS) coupled to a Quadropole Time-of-Flight (QTOF) mass spectrometer; additionally, fatty acids from each sample were analyzed using gas chromatography-mass spectrometry (GC-MS) to prove consistent signatures with those determined by Allen et al. in 2010 for similar microbial mat samples. In accordance with those findings, 2-methylhopanoids were detected, as well as limited signals from higher (vascular) plants, the latter of which suggests terrestrial inputs, potentially from runoff. The rarely detected presence of 3-methylhopanoids appears in a significant portion of the samples, though further isolations of the molecule are needed to confirm. While all lipid profiles were relatively similar, certain differences in relative composition are likely attributable to morphological differences of the mats, some of which allow deeper oxygen and/or sunlight penetration, which influence the microbial community. However, overall similarities of transient and persistent lipids suggest that the microbial communities of both the non-lithified microbial mats and stromatolites are similar.

  4. Fuzzy modelling of Atlantic salmon physical habitat

    Science.gov (United States)

    St-Hilaire, André; Mocq, Julien; Cunjak, Richard

    2015-04-01

    Fish habitat models typically attempt to quantify the amount of available river habitat for a given fish species for various flow and hydraulic conditions. To achieve this, information on the preferred range of values of key physical habitat variables (e.g. water level, velocity, substrate diameter) for the targeted fishs pecies need to be modelled. In this context, we developed several habitat suitability indices sets for three Atlantic salmon life stages (young-of-the-year (YOY), parr, spawning adults) with the help of fuzzy logic modeling. Using the knowledge of twenty-seven experts, from both sides of the Atlantic Ocean, we defined fuzzy sets of four variables (depth, substrate size, velocity and Habitat Suitability Index, or HSI) and associated fuzzy rules. When applied to the Romaine River (Canada), median curves of standardized Weighted Usable Area (WUA) were calculated and a confidence interval was obtained by bootstrap resampling. Despite the large range of WUA covered by the expert WUA curves, confidence intervals were relatively narrow: an average width of 0.095 (on a scale of 0 to 1) for spawning habitat, 0.155 for parr rearing habitat and 0.160 for YOY rearing habitat. When considering an environmental flow value corresponding to 90% of the maximum reached by WUA curve, results seem acceptable for the Romaine River. Generally, this proposed fuzzy logic method seems suitable to model habitat availability for the three life stages, while also providing an estimate of uncertainty in salmon preferences.

  5. Habitat stability, predation risk and 'memory syndromes'.

    Science.gov (United States)

    Dalesman, S; Rendle, A; Dall, S R X

    2015-05-27

    Habitat stability and predation pressure are thought to be major drivers in the evolutionary maintenance of behavioural syndromes, with trait covariance only occurring within specific habitats. However, animals also exhibit behavioural plasticity, often through memory formation. Memory formation across traits may be linked, with covariance in memory traits (memory syndromes) selected under particular environmental conditions. This study tests whether the pond snail, Lymnaea stagnalis, demonstrates consistency among memory traits ('memory syndrome') related to threat avoidance and foraging. We used eight populations originating from three different habitat types: i) laboratory populations (stable habitat, predator-free); ii) river populations (fairly stable habitat, fish predation); and iii) ditch populations (unstable habitat, invertebrate predation). At a population level, there was a negative relationship between memories related to threat avoidance and food selectivity, but no consistency within habitat type. At an individual level, covariance between memory traits was dependent on habitat. Laboratory populations showed no covariance among memory traits, whereas river populations showed a positive correlation between food memories, and ditch populations demonstrated a negative relationship between threat memory and food memories. Therefore, selection pressures among habitats appear to act independently on memory trait covariation at an individual level and the average response within a population.

  6. Microbial Cell Dynamics Lab (MCDL)

    Data.gov (United States)

    Federal Laboratory Consortium — The Microbial Cell Dynamics Laboratory at PNNL enables scientists to study the molecular details of microbes under relevant environmental conditions. The MCDL seeks...

  7. Two-dimensional physical habitat modeling of effects of habitat structures on urban stream restoration

    Directory of Open Access Journals (Sweden)

    Dongkyun Im

    2011-12-01

    Full Text Available River corridors, even if highly modified or degraded, still provide important habitats for numerous biological species, and carry high aesthetic and economic values. One of the keys to urban stream restoration is recovery and maintenance of ecological flows sufficient to sustain aquatic ecosystems. In this study, the Hongje Stream in the Seoul metropolitan area of Korea was selected for evaluating a physically-based habitat with and without habitat structures. The potential value of the aquatic habitat was evaluated by a weighted usable area (WUA using River2D, a two-dimensional hydraulic model. The habitat suitability for Zacco platypus in the Hongje Stream was simulated with and without habitat structures. The computed WUA values for the boulder, spur dike, and riffle increased by about 2%, 7%, and 131%, respectively, after their construction. Also, the three habitat structures, especially the riffle, can contribute to increasing hydraulic heterogeneity and enhancing habitat diversity.

  8. Habitat Ecology Visual Surveys of Demersal Fishes and Habitats off California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Since 1992, the Habitat Ecology team has been conducting fishery independent, visual surveys of demersal fishes and associated habitats in deep water (20 to 900...

  9. Decoupling of microbial carbon, nitrogen, and phosphorus cycling in response to extreme temperature events

    Science.gov (United States)

    Mooshammer, Maria; Hofhansl, Florian; Frank, Alexander H.; Wanek, Wolfgang; Hämmerle, Ieda; Leitner, Sonja; Schnecker, Jörg; Wild, Birgit; Watzka, Margarete; Keiblinger, Katharina M.; Zechmeister-Boltenstern, Sophie; Richter, Andreas

    2017-01-01

    Predicted changes in the intensity and frequency of climate extremes urge a better mechanistic understanding of the stress response of microbially mediated carbon (C) and nutrient cycling processes. We analyzed the resistance and resilience of microbial C, nitrogen (N), and phosphorus (P) cycling processes and microbial community composition in decomposing plant litter to transient, but severe, temperature disturbances, namely, freeze-thaw and heat. Disturbances led temporarily to a more rapid cycling of C and N but caused a down-regulation of P cycling. In contrast to the fast recovery of the initially stimulated C and N processes, we found a slow recovery of P mineralization rates, which was not accompanied by significant changes in community composition. The functional and structural responses to the two distinct temperature disturbances were markedly similar, suggesting that direct negative physical effects and costs associated with the stress response were comparable. Moreover, the stress response of extracellular enzyme activities, but not that of intracellular microbial processes (for example, respiration or N mineralization), was dependent on the nutrient content of the resource through its effect on microbial physiology and community composition. Our laboratory study provides novel insights into the mechanisms of microbial functional stress responses that can serve as a basis for field studies and, in particular, illustrates the need for a closer integration of microbial C-N-P interactions into climate extremes research. PMID:28508070

  10. Microbial products II

    Energy Technology Data Exchange (ETDEWEB)

    Pape, H; Rehm, H J [eds.

    1986-01-01

    The present volume deals mainly with compounds which have been detected as natural microbial products. Part 1 of this volume introduces the general aspects of the overproduction of metabolites and the concepts and genetics of secondary metabolism. Compounds such as nucleosides, nucleotides, coenzymes, vitamins and lipids are dealt with in part 2. Part 3 then is devoted to products and antibiotics with uses im medicine, veterinary medicine, plant protection and metabolites with antitumor activity. Several secondary metabolites have found uses in human and animal health care. With 244 figs., 109 tabs.

  11. Microbial bebop: creating music from complex dynamics in microbial ecology.

    Directory of Open Access Journals (Sweden)

    Peter Larsen

    Full Text Available In order for society to make effective policy decisions on complex and far-reaching subjects, such as appropriate responses to global climate change, scientists must effectively communicate complex results to the non-scientifically specialized public. However, there are few ways however to transform highly complicated scientific data into formats that are engaging to the general community. Taking inspiration from patterns observed in nature and from some of the principles of jazz bebop improvisation, we have generated Microbial Bebop, a method by which microbial environmental data are transformed into music. Microbial Bebop uses meter, pitch, duration, and harmony to highlight the relationships between multiple data types in complex biological datasets. We use a comprehensive microbial ecology, time course dataset collected at the L4 marine monitoring station in the Western English Channel as an example of microbial ecological data that can be transformed into music. Four compositions were generated (www.bio.anl.gov/MicrobialBebop.htm. from L4 Station data using Microbial Bebop. Each composition, though deriving from the same dataset, is created to highlight different relationships between environmental conditions and microbial community structure. The approach presented here can be applied to a wide variety of complex biological datasets.

  12. Microbial bebop: creating music from complex dynamics in microbial ecology.

    Science.gov (United States)

    Larsen, Peter; Gilbert, Jack

    2013-01-01

    In order for society to make effective policy decisions on complex and far-reaching subjects, such as appropriate responses to global climate change, scientists must effectively communicate complex results to the non-scientifically specialized public. However, there are few ways however to transform highly complicated scientific data into formats that are engaging to the general community. Taking inspiration from patterns observed in nature and from some of the principles of jazz bebop improvisation, we have generated Microbial Bebop, a method by which microbial environmental data are transformed into music. Microbial Bebop uses meter, pitch, duration, and harmony to highlight the relationships between multiple data types in complex biological datasets. We use a comprehensive microbial ecology, time course dataset collected at the L4 marine monitoring station in the Western English Channel as an example of microbial ecological data that can be transformed into music. Four compositions were generated (www.bio.anl.gov/MicrobialBebop.htm.) from L4 Station data using Microbial Bebop. Each composition, though deriving from the same dataset, is created to highlight different relationships between environmental conditions and microbial community structure. The approach presented here can be applied to a wide variety of complex biological datasets.

  13. Plasma transport studies using transient techniques

    International Nuclear Information System (INIS)

    Simonen, T.C.; Brower, D.L.; Efthimion, P.

    1991-01-01

    Selected topics from the Transient Transport sessions of the Transport Task Force Workshop, held February 19-23, 1990, in Hilton Head, South Carolina are summarized. Presentations on sawtooth propagation, ECH modulation, particle modulation, and H-mode transitions are included. The research results presented indicated a growing theoretical understanding and experimental sophistication in the application of transient techniques to transport studies. (Author)

  14. The LOFAR Transients Key Science Project

    NARCIS (Netherlands)

    Stappers, B.; Fender, R.; Wijers, R.

    2009-01-01

    The Transients Key Science Project (TKP) is one of six Key Science Projects of the next generation radio telescope LOFAR. Its aim is the study of transient and variable low-frequency radio sources with an extremely broad science case ranging from relativistic jet sources to pulsars, exoplanets,

  15. Transient receptor potential channels in essential hypertension

    DEFF Research Database (Denmark)

    Liu, Daoyan; Scholze, Alexandra; Zhu, Zhiming

    2006-01-01

    The role of nonselective cation channels of the transient receptor potential channel (TRPC) family in essential hypertension has not yet been investigated.......The role of nonselective cation channels of the transient receptor potential channel (TRPC) family in essential hypertension has not yet been investigated....

  16. Similar microbial communities found on two distant seafloor basalts

    Directory of Open Access Journals (Sweden)

    Esther eSinger

    2015-12-01

    Full Text Available The oceanic crust forms two thirds of the Earth’s surface and hosts a large phylogenetic and functional diversity of microorganisms. While advances have been made in the sedimentary realm, our understanding of the igneous rock portion as a microbial habitat has remained limited. We present the first comparative metagenomic microbial community analysis from ocean floor basalt environments at the Lō’ihi Seamount, Hawai’i, and the East Pacific Rise (EPR (9˚N. Phylogenetic analysis indicates the presence of a total of 43 bacterial and archaeal mono-phyletic groups, dominated by Alpha- and Gammaproteobacteria, as well as Thaumarchaeota. Functional gene analysis suggests that these Thaumarchaeota play an important role in ammonium oxidation on seafloor basalts. In addition to ammonium oxidation, the seafloor basalt habitat reveals a wide spectrum of other metabolic potentials, including CO2 fixation, denitrification, dissimilatory sulfate reduction, and sulfur oxidation. Basalt communities from Lō’ihi and the EPR show considerable metabolic and phylogenetic overlap down to the genus level despite geographic distance and slightly different seafloor basalt mineralogy.

  17. Soil Microbial Community Contribution to Small Headwater Stream Metabolism.

    Science.gov (United States)

    Clapcott, J. E.; Gooderham, J. P.; Barmuta, L. A.; Davies, P. E.

    2005-05-01

    The temporal dynamics of sediment respiration were examined in seven small headwater streams in forested catchments in 2004. A strong seasonal response was observed with higher respiration rates in depositional zones than in gravel runs. The data were also examined in the context of proportional habitat distributions that highlighted the importance of high flow events in shaping whole stream metabolic budgets. This study specifically examines the question of terrestrial soil respiration contribution to whole stream metabolism by the controlled inundation of terrestrial soils. The experiment included six experimentally inundated terrestrial zones, six terrestrial controls, and six in-stream depositional zones. Sediment bacterial respiration was measured using 14C leucine incorporation and cotton strip bioassays were also employed to provide an indicative measure of sediment microbial activity. Despite high variability and exhibiting significantly lower bacterial activity than in-stream sediments, modelling using flow data and habitat mapping illustrated the important contribution of terrestrial soil respiration to the whole stream metabolic budgets of small headwater streams. In addition, microbial community composition examined using phospholipid fatty acid analysis clearly differentiated between terrestrial and aquatic communities. Freshly inundated terrestrial communities remained similar to un-inundated controls after 28 days.

  18. Synchronizing noisy nonidentical oscillators by transient uncoupling

    Energy Technology Data Exchange (ETDEWEB)

    Tandon, Aditya, E-mail: adityat@iitk.ac.in; Mannattil, Manu, E-mail: mmanu@iitk.ac.in [Department of Physics, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016 (India); Schröder, Malte, E-mail: malte@nld.ds.mpg.de [Network Dynamics, Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen (Germany); Timme, Marc, E-mail: timme@nld.ds.mpg.de [Network Dynamics, Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen (Germany); Department of Physics, Technical University of Darmstadt, 64289 Darmstadt (Germany); Chakraborty, Sagar, E-mail: sagarc@iitk.ac.in [Department of Physics, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016 (India); Mechanics and Applied Mathematics Group, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016 (India)

    2016-09-15

    Synchronization is the process of achieving identical dynamics among coupled identical units. If the units are different from each other, their dynamics cannot become identical; yet, after transients, there may emerge a functional relationship between them—a phenomenon termed “generalized synchronization.” Here, we show that the concept of transient uncoupling, recently introduced for synchronizing identical units, also supports generalized synchronization among nonidentical chaotic units. Generalized synchronization can be achieved by transient uncoupling even when it is impossible by regular coupling. We furthermore demonstrate that transient uncoupling stabilizes synchronization in the presence of common noise. Transient uncoupling works best if the units stay uncoupled whenever the driven orbit visits regions that are locally diverging in its phase space. Thus, to select a favorable uncoupling region, we propose an intuitive method that measures the local divergence at the phase points of the driven unit's trajectory by linearizing the flow and subsequently suppresses the divergence by uncoupling.

  19. Transient survivability of LMR oxide fuel pins

    International Nuclear Information System (INIS)

    Weber, E.T.; Pitner, A.L.; Bard, F.E.; Culley, G.E.; Hunter, C.W.

    1986-01-01

    Fuel pin integrity during transient events must be assessed for both the core design and safety analysis phases of a reactor project. A significant increase in the experience related to limits of integrity for oxide fuel pins in transient overpower events has been realized from testing of fuel pins irradiated in FFTF and PFR. Fourteen FFTF irradiated fuel pins were tested in TREAT, representing a range of burnups, overpower ramp rates and maximum overpower conditions. Results of these tests along with similar testing in the PFR/TREAT program, provide a demonstration of significant safety margins for oxide fuel pins. Useful information applied in analytical extrapolation of fuel pin test data have been developed from laboratory transient tests on irradiated fuel cladding (FCTT) and on unirradiated fuel pellet deformation. These refinements in oxide fuel transient performance are being applied in assessment of transient capabilities of long lifetime fuel designs using ferritic cladding

  20. Characterizing transient noise in the LIGO detectors

    Science.gov (United States)

    Nuttall, L. K.

    2018-05-01

    Data from the LIGO detectors typically contain many non-Gaussian noise transients which arise due to instrumental and environmental conditions. These non-Gaussian transients can be an issue for the modelled and unmodelled transient gravitational-wave searches, as they can mask or mimic a true signal. Data quality can change quite rapidly, making it imperative to track and find new sources of transient noise so that data are minimally contaminated. Several examples of transient noise and the tools used to track them are presented. These instances serve to highlight the diverse range of noise sources present at the LIGO detectors during their second observing run. This article is part of a discussion meeting issue `The promises of gravitational-wave astronomy'.

  1. Nuclear reactors transients identification and classification system

    International Nuclear Information System (INIS)

    Bianchi, Paulo Henrique

    2008-01-01

    This work describes the study and test of a system capable to identify and classify transients in thermo-hydraulic systems, using a neural network technique of the self-organizing maps (SOM) type, with the objective of implanting it on the new generations of nuclear reactors. The technique developed in this work consists on the use of multiple networks to do the classification and identification of the transient states, being each network a specialist at one respective transient of the system, that compete with each other using the quantization error, that is a measure given by this type of neural network. This technique showed very promising characteristics that allow the development of new functionalities in future projects. One of these characteristics consists on the potential of each network, besides responding what transient is in course, could give additional information about that transient. (author)

  2. Habitus constitution in habitat production

    Directory of Open Access Journals (Sweden)

    Paulo Romano Reschilian

    2011-06-01

    Full Text Available Based on the approach suggested by Pierre Bourdieu's sociology, this article demonstrates that the construction of the notion of habitus can reflect on the production of habitat in the form of precarious settlements, such as substandard housing or shantytowns. This study employs a multidimensional perspective, because precarious settlements are not rational and do not follow modern established or existing social and urbanistic rules and parameters. The review will extend beyond the scope suggested by historical materialism under the marxian view of urban sociology. To investigate this phenomenon, the author of this article studied a precarious settlement in the municipality of São José dos Campos, called Nova Tatetuba, which was removed in 2004 as part of a shantytown clearing program established by that city in 2000.

  3. Host-specific effects of soil microbial filtrates prevail over those of arbuscular mycorrhizae in a fragmented landscape.

    Science.gov (United States)

    Pizano, Camila; Mangan, Scott A; Graham, James H; Kitajima, Kaoru

    2017-09-01

    Plant-soil interactions have been shown to determine plant community composition in a wide range of environments. However, how plants distinctly interact with beneficial and detrimental organisms across mosaic landscapes containing fragmented habitats is still poorly understood. We experimentally tested feedback responses between plants and soil microbial communities from adjacent habitats across a disturbance gradient within a human-modified tropical montane landscape. In a greenhouse experiment, two components of soil microbial communities were amplified; arbuscular mycorrhizal fungi (AMF) and a filtrate excluding AMF spores from the soils of pastures (high disturbance), coffee plantations (intermediate disturbance), and forest fragments (low disturbance), using potted seedlings of 11 plant species common in these habitats (pasture grass, coffee, and nine native species). We then examined their effects on growth of these same 11 host species with reciprocal habitat inoculation. Most plant species received a similar benefit from AMF, but differed in their response to the filtrates from the three habitats. Soil filtrate from pastures had a net negative effect on plant growth, while filtrates from coffee plantations and forests had a net positive effect on plant growth. Pasture grass, coffee, and five pioneer tree species performed better with the filtrate from "away" (where these species rarely occur) compared to "home" (where these species typically occur) habitat soils, while four shade-tolerant tree species grew similarly with filtrates from different habitats. These results suggest that pastures accumulate species-specific soil enemies, while coffee plantations and forests accumulate beneficial soil microbes that benefit pioneer native plants and coffee, respectively. Thus, compared to AMF, soil filtrates exerted stronger habitat and host-specific effects on plants, being more important mediators of plant-soil feedbacks across contrasting habitats. © 2017 by

  4. Livestock grazing, wildlife habitat, and rangeland values

    Science.gov (United States)

    Paul R. Krausman; David E. Naugle; Michael R. Frisina; Rick Northrup; Vernon C. Bleich; William M. Block; Mark C. Wallace; Jeffrey D. Wright

    2009-01-01

    Livestock managers make and implement grazing management decisions to achieve a variety of objectives including livestock production, sustainable grazing, and wildlife habitat enhancement. Assessed values of grazing lands and ranches are often based on aesthetics and wildlife habitat or recreational values, which can exceed agricultural values, thus providing...

  5. Habitat Use and Selection by Giant Pandas

    Science.gov (United States)

    Hull, Vanessa; Zhang, Jindong; Huang, Jinyan; Zhou, Shiqiang; Viña, Andrés; Shortridge, Ashton; Li, Rengui; Liu, Dian; Xu, Weihua; Ouyang, Zhiyun; Zhang, Hemin; Liu, Jianguo

    2016-01-01

    Animals make choices about where to spend their time in complex and dynamic landscapes, choices that reveal information about their biology that in turn can be used to guide their conservation. Using GPS collars, we conducted a novel individual-based analysis of habitat use and selection by the elusive and endangered giant pandas (Ailuropoda melanoleuca). We constructed spatial autoregressive resource utilization functions (RUF) to model the relationship between the pandas' utilization distributions and various habitat characteristics over a continuous space across seasons. Results reveal several new insights, including use of a broader range of habitat characteristics than previously understood for the species, particularly steep slopes and non-forest areas. We also used compositional analysis to analyze habitat selection (use with respect to availability of habitat types) at two selection levels. Pandas selected against low terrain position and against the highest clumped forest at the at-home range level, but no significant factors were identified at the within-home range level. Our results have implications for modeling and managing the habitat of this endangered species by illustrating how individual pandas relate to habitat and make choices that differ from assumptions made in broad scale models. Our study also highlights the value of using a spatial autoregressive RUF approach on animal species for which a complete picture of individual-level habitat use and selection across space is otherwise lacking. PMID:27627805

  6. Island Species Richness Increases with Habitat Diversity

    NARCIS (Netherlands)

    Hortal, J.; Triantis, K.A.; Meiri, S.; Thebault, E.M.C.; Sfenthourakis, S.

    2009-01-01

    Species richness is commonly thought to increase with habitat diversity. However, a recent theoretical model aiming to unify niche and island biogeography theories predicted a hump-shaped relationship between richness and habitat diversity. Given the contradiction between model results and previous

  7. Estuaries and Tidal Marshes. Habitat Pac.

    Science.gov (United States)

    Fish and Wildlife Service (Dept. of Interior), Washington, DC.

    This educational packet consists of an overview, three lesson plans, student data sheets, and a poster. The overview examines estuaries and tidal or salt marshes by discussing the plants and animals in these habitats, marsh productivity, benefits and management of the habitats, historical aspects, and development and pollution. A glossary and list…

  8. Pollen and gene flow in fragmented habitats

    NARCIS (Netherlands)

    Kwak, Manja M.; Velterop, Odilia; van Andel, Jelte

    . Habitat fragmentation affects both plants and pollinators. Habitat fragmentation leads to changes in species richness, population number and size, density, and shape, thus to changes in the spatial arrangement of flowers. These changes influence the amount of food for flower-visiting insects and

  9. Habitat Use and Selection by Giant Pandas.

    Directory of Open Access Journals (Sweden)

    Vanessa Hull

    Full Text Available Animals make choices about where to spend their time in complex and dynamic landscapes, choices that reveal information about their biology that in turn can be used to guide their conservation. Using GPS collars, we conducted a novel individual-based analysis of habitat use and selection by the elusive and endangered giant pandas (Ailuropoda melanoleuca. We constructed spatial autoregressive resource utilization functions (RUF to model the relationship between the pandas' utilization distributions and various habitat characteristics over a continuous space across seasons. Results reveal several new insights, including use of a broader range of habitat characteristics than previously understood for the species, particularly steep slopes and non-forest areas. We also used compositional analysis to analyze habitat selection (use with respect to availability of habitat types at two selection levels. Pandas selected against low terrain position and against the highest clumped forest at the at-home range level, but no significant factors were identified at the within-home range level. Our results have implications for modeling and managing the habitat of this endangered species by illustrating how individual pandas relate to habitat and make choices that differ from assumptions made in broad scale models. Our study also highlights the value of using a spatial autoregressive RUF approach on animal species for which a complete picture of individual-level habitat use and selection across space is otherwise lacking.

  10. Microbial ecology of phototrophic biofilms

    NARCIS (Netherlands)

    Roeselers, G.

    2007-01-01

    Biofilms are layered structures of microbial cells and an extracellular matrix of polymeric substances, associated with surfaces and interfaces. Biofilms trap nutrients for growth of the enclosed microbial community and help prevent detachment of cells from surfaces in flowing systems. Phototrophic

  11. Clinical applications of transient elastography

    Directory of Open Access Journals (Sweden)

    Kyu Sik Jung

    2012-06-01

    Full Text Available Chronic liver disease represents a major public health problem, accounting for significant morbidity and mortality worldwide. As prognosis and management depend mainly on the amount and progression of liver fibrosis, accurate quantification of liver fibrosis is essential for therapeutic decision-making and follow-up of chronic liver diseases. Even though liver biopsy is the gold standard for evaluation of liver fibrosis, non-invasive methods that could substitute for invasive procedures have been investigated during past decades. Transient elastography (TE, FibroScan® is a novel non-invasive method for assessment of liver fibrosis with chronic liver disease. TE can be performed in the outpatient clinic with immediate results and excellent reproducibility. Its diagnostic accuracy for assessment of liver fibrosis has been demonstrated in patients with chronic viral hepatitis; as a result, unnecessary liver biopsy could be avoided in some patients. Moreover, due to its excellent patient acceptance, TE could be used for monitoring disease progression or predicting development of liver-related complications. This review aims at discussing the usefulness of TE in clinical practice.

  12. Defect detection using transient thermography

    International Nuclear Information System (INIS)

    Mohd Zaki Umar; Ibrahim Ahmad; Ab Razak Hamzah; Wan Saffiey Wan Abdullah

    2008-08-01

    An experimental research had been carried out to study the potential of transient thermography in detecting sub-surface defect of non-metal material. In this research, eight pieces of bakelite material were used as samples. Each samples had a sub-surface defect in the circular shape with different diameters and depths. Experiment was conducted using one-sided Pulsed Thermal technique. Heating of samples were done using 30 kWatt adjustable quartz lamp while infra red (IR) images of samples were recorded using THV 550 IR camera. These IR images were then analysed with ThermofitTMPro software to obtain the Maximum Absolute Differential Temperature Signal value, ΔΤ m ax and the time of its appearance, τ m ax (ΔΤ). Result showed that all defects were able to be detected even for the smallest and deepest defect (diameter = 5 mm and depth = 4 mm). However the highest value of Differential Temperature Signal (ΔΤ m ax), were obtained at defect with the largest diameter, 20 mm and at the shallowest depth, 1 mm. As a conclusion, the sensitivity of the pulsed thermography technique to detect sub-surface defects of bakelite material is proportionately related with the size of defect diameter if the defects are at the same depth. On the contrary, the sensitivity of the pulsed thermography technique inversely related with the depth of defect if the defects have similar diameter size. (Author)

  13. Transient shocks beyond the heliopause

    International Nuclear Information System (INIS)

    Fermo, R L; Pogorelov, N V; Burlaga, L F

    2015-01-01

    The heliopause is a rich, dynamic surface affected by the time-dependent solar wind. Stream interactions due to coronal mass ejections (CMEs), corotating interaction regions (CIRs), and other transient phenomena are known to merge producing global merged interaction regions (GMIRs). Numerical simulations of the solar wind interaction with the local interstellar medium (LISM) show that GMIRs, as well other time-dependent structures in the solar wind, may produce compression/rarefaction waves and shocks in the LISM behind the heliopause. These shocks may initiate wave activity observed by the Voyager spacecraft. The magnetometer onboard Voyager 1 indeed observed a few structures that may be interpreted as shocks. We present numerical simulations of such shocks in the year of 2000, when both Voyager spacecraft were in the supersonic solar wind region, and in 2012, when Voyager 1 observed traveling shocks. In the former case, Voyager observations themselves provide time- dependent boundary conditions in the solar wind. In the latter case, we use OMNI data at 1 AU to analyze the plasma and magnetic field behavior after Voyager 1 crossed the heliospheric boundary. Numerical results are compared with spacecraft observations. (paper)

  14. Transient phenomena in multiphase flow

    International Nuclear Information System (INIS)

    Afgan, N.H.

    1988-01-01

    This book is devoted to formulation of the two-phase system. Emphasis is given to classical instantaneous equations of mass momentum and energy for local conditions and respective averaging procedures and their relevance to the structure of transfer laws. In formulating an equation for a two-velocity continuum, two-phase dispersed flow, two-velocity and local inertial effects associated with contraction and expansion of the mixture have been considered. Particular attention is paid to the effects of interface topology and area concentration as well as the latter's dependence on interfacial transfer laws. Also covered are low bubble concentrations in basic nonuniform unsteady flow where interactions between bubbles are negligible but where the effects of bubbles must still be considered. Special emphasis has been given to the pairwise interaction of the bubble and respective hydrodynamic equations describing the motion of a pair of spherical bubbles through a liquid This book introduces turbulence phenomena in two-phase flow and related problems of phase distribution in two-phase flow. This includes an extensive survey of turbulence and phase distribution models in transient two-phase flow. It is shown that if the turbulent structure of the continuous phase of bubbly two-phase is either measured or can be predicted, then the observed lateral phase distribution can be determined by using an multidimensional two-fluid model in which all lateral forces are properly modeled

  15. Phylogenetic and functional analysis of metagenome sequence from high-temperature archaeal habitats demonstrate linkages between metabolic potential and geochemistry

    Directory of Open Access Journals (Sweden)

    William P. Inskeep

    2013-05-01

    Full Text Available Geothermal habitats in Yellowstone National Park (YNP provide an unparalled opportunity to understand the environmental factors that control the distribution of archaea in thermal habitats. Here we describe, analyze and synthesize metagenomic and geochemical data collected from seven high-temperature sites that contain microbial communities dominated by archaea relative to bacteria. The specific objectives of the study were to use metagenome sequencing to determine the structure and functional capacity of thermophilic archaeal-dominated microbial communities across a pH range from 2.5 to 6.4 and to discuss specific examples where the metabolic potential correlated with measured environmental parameters and geochemical processes occurring in situ. Random shotgun metagenome sequence (~40-45 Mbase Sanger sequencing per site was obtained from environmental DNA extracted from high-temperature sediments and/or microbial mats and subjected to numerous phylogenetic and functional analyses. Analysis of individual sequences (e.g., MEGAN and G+C content and assemblies from each habitat type revealed the presence of dominant archaeal populations in all environments, 10 of whose genomes were largely reconstructed from the sequence data. Analysis of protein family occurrence, particularly of those involved in energy conservation, electron transport and autotrophic metabolism, revealed significant differences in metabolic strategies across sites consistent with differences in major geochemical attributes (e.g., sulfide, oxygen, pH. These observations provide an ecological basis for understanding the distribution of indigenous archaeal lineages across high temperature systems of YNP.

  16. Fish habitat mitigation measures for hydrotechnical projects

    International Nuclear Information System (INIS)

    McPhail, G.D.; MacMillan, D.B.; Katopodis, C.

    1992-01-01

    In recent years, the identification and mitigation of environmental impacts of hydrotechnical projects, particularly on fish and fish habitats, have become a major component of project planning and design. Potential impacts to fish and fish habitat may include increased fish mortality, decreased species diversity, and loss or decreases in fish production due to loss of habitat or alteration of its suitability. These impacts arise from flooding of riverine habitat, alteration of flow quantity and distribution, changes in morphology, and alteration of water quality, including suspended sediments, temperature, dissolved oxygen, and mercury. The results of a study for the Canadian Federal Department of Fisheries and Oceans Central and Arctic Region, examining fish habitat mitigation techniques for their applicability to hydrotechnical projects in Canada are summarized. The requirements for achievement and verification of the no net loss policy for a project are discussed. 10 refs., 2 tabs

  17. L-Reactor Habitat Mitigation Study

    International Nuclear Information System (INIS)

    1988-02-01

    The L-Reactor Fish and Wildlife Resource Mitigation Study was conducted to quantify the effects on habitat of the L-Reactor restart and to identify the appropriate mitigation for these impacts. The completed project evaluated in this study includes construction of a 1000 acre reactor cooling reservoir formed by damming Steel Creek. Habitat impacts identified include a loss of approximately 3,700 average annual habitat units. This report presents a mitigation plan, Plan A, to offset these habitat losses. Plan A will offset losses for all species studied, except whitetailed deer. The South Carolina Wildlife and Marine Resources Department strongly recommends creation of a game management area to provide realistic mitigation for loss of deer habitats. 10 refs., 5 figs., 3 tabs

  18. Hydrodynamics of microbial filter feeding

    DEFF Research Database (Denmark)

    Nielsen, Lasse Tor; Asadzadeh, Seyed Saeed; Dölger, Julia

    2017-01-01

    Microbial filter feeders are an important group of grazers, significant to the microbial loop, aquatic food webs, and biogeochemical cycling. Our understanding of microbial filter feeding is poor, and, importantly, it is unknown what force microbial filter feeders must generate to process adequate......-feeding choanoflagellate Diaphanoeca grandis using particle tracking, and demonstrate that the current understanding of microbial filter feeding is inconsistent with computational fluid dynamics (CFD) and analytical estimates. Both approaches underestimate observed filtration rates by more than an order of magnitude......; the beating flagellum is simply unable to draw enough water through the fine filter. We find similar discrepancies for other choanoflagellate species, highlighting an apparent paradox. Our observations motivate us to suggest a radically different filtration mechanism that requires a flagellar vane (sheet...

  19. How microbial community composition regulates coral disease development.

    Directory of Open Access Journals (Sweden)

    Justin Mao-Jones

    2010-03-01

    Full Text Available Reef coral cover is in rapid decline worldwide, in part due to bleaching (expulsion of photosynthetic symbionts and outbreaks of infectious disease. One important factor associated with bleaching and in disease transmission is a shift in the composition of the microbial community in the mucus layer surrounding the coral: the resident microbial community-which is critical to the healthy functioning of the coral holobiont-is replaced by pathogenic microbes, often species of Vibrio. In this paper we develop computational models for microbial community dynamics in the mucus layer in order to understand how the surface microbial community responds to changes in environmental conditions, and under what circumstances it becomes vulnerable to overgrowth by pathogens. Some of our model's assumptions and parameter values are based on Vibrio spp. as a model system for other established and emerging coral pathogens. We find that the pattern of interactions in the surface microbial community facilitates the existence of alternate stable states, one dominated by antibiotic-producing beneficial microbes and the other pathogen-dominated. A shift to pathogen dominance under transient stressful conditions, such as a brief warming spell, may persist long after environmental conditions have returned to normal. This prediction is consistent with experimental findings that antibiotic properties of Acropora palmata mucus did not return to normal long after temperatures had fallen. Long-term loss of antibiotic activity eliminates a critical component in coral defense against disease, giving pathogens an extended opportunity to infect and spread within the host, elevating the risk of coral bleaching, disease, and mortality.

  20. How microbial community composition regulates coral disease development.

    Science.gov (United States)

    Mao-Jones, Justin; Ritchie, Kim B; Jones, Laura E; Ellner, Stephen P

    2010-03-30

    Reef coral cover is in rapid decline worldwide, in part due to bleaching (expulsion of photosynthetic symbionts) and outbreaks of infectious disease. One important factor associated with bleaching and in disease transmission is a shift in the composition of the microbial community in the mucus layer surrounding the coral: the resident microbial community-which is critical to the healthy functioning of the coral holobiont-is replaced by pathogenic microbes, often species of Vibrio. In this paper we develop computational models for microbial community dynamics in the mucus layer in order to understand how the surface microbial community responds to changes in environmental conditions, and under what circumstances it becomes vulnerable to overgrowth by pathogens. Some of our model's assumptions and parameter values are based on Vibrio spp. as a model system for other established and emerging coral pathogens. We find that the pattern of interactions in the surface microbial community facilitates the existence of alternate stable states, one dominated by antibiotic-producing beneficial microbes and the other pathogen-dominated. A shift to pathogen dominance under transient stressful conditions, such as a brief warming spell, may persist long after environmental conditions have returned to normal. This prediction is consistent with experimental findings that antibiotic properties of Acropora palmata mucus did not return to normal long after temperatures had fallen. Long-term loss of antibiotic activity eliminates a critical component in coral defense against disease, giving pathogens an extended opportunity to infect and spread within the host, elevating the risk of coral bleaching, disease, and mortality.

  1. Measuring microbial fitness in a field reciprocal transplant experiment.

    Science.gov (United States)

    Boynton, Primrose J; Stelkens, Rike; Kowallik, Vienna; Greig, Duncan

    2017-05-01

    Microbial fitness is easy to measure in the laboratory, but difficult to measure in the field. Laboratory fitness assays make use of controlled conditions and genetically modified organisms, neither of which are available in the field. Among other applications, fitness assays can help researchers detect adaptation to different habitats or locations. We designed a competitive fitness assay to detect adaptation of Saccharomyces paradoxus isolates to the habitat they were isolated from (oak or larch leaf litter). The assay accurately measures relative fitness by tracking genotype frequency changes in the field using digital droplet PCR (DDPCR). We expected locally adapted S. paradoxus strains to increase in frequency over time when growing on the leaf litter type from which they were isolated. The DDPCR assay successfully detected fitness differences among S. paradoxus strains, but did not find a tendency for strains to be adapted to the habitat they were isolated from. Instead, we found that the natural alleles of the hexose transport gene we used to distinguish S. paradoxus strains had significant effects on fitness. The origin of a strain also affected its fitness: strains isolated from oak litter were generally fitter than strains from larch litter. Our results suggest that dispersal limitation and genetic drift shape S. paradoxus populations in the forest more than local selection does, although further research is needed to confirm this. Tracking genotype frequency changes using DDPCR is a practical and accurate microbial fitness assay for natural environments. © 2016 The Authors. Molecular Ecology Resources Published by John Wiley & Sons Ltd.

  2. Fission gas behavior during fast thermal transients

    International Nuclear Information System (INIS)

    Esteves, R.G.

    1976-01-01

    The behavior of non-equilibrium fission in fuel elements undergoing fast thermal transients is analyzed. To facilitate the analysis, a new variable, the equilibrium variable (EV) is defined. This variable, together with bubble radius, completely specifies a bubble with respect to its size and equilibrium condition. The analysis is coded using a two-variable (radius and EV) multigroup numerical approximation that accepts as input the time-temperature history, the time-fission rate history, and the time-thermal gradient history of the fuel element. Studies were performed to test the code for convergence with respect to the time interval and the number of groups chosen. For a series of transient simulation studies, the measurements obtained at HEDL (microscopic examination of intragranular porosity in oxide fuel transient-tested in TREAT) are used. Two different transient histories were selected; the first, a high-temperature transient (HTT) with a peak at 2477 0 K and the second, a low-temperature transient (LTT) with a peak-temperature at 2000 0 K. The LTT was simulated for three different conditions: Bubbles were allowed to move via (a) only biased migration, (b) via random migration, and (c) via both mechanisms. The HTT was also run for both mechanisms. The agreement with HEDL microscopic observations was fair for bubbles smaller than 964 A in diameter, and poor for larger bubbles. Bubbles that grew during the heat-up part of the transient were frozen at a larger size during the cool down

  3. Pressure adaptation is linked to thermal adaptation in salt-saturated marine habitats.

    Science.gov (United States)

    Alcaide, María; Stogios, Peter J; Lafraya, Álvaro; Tchigvintsev, Anatoli; Flick, Robert; Bargiela, Rafael; Chernikova, Tatyana N; Reva, Oleg N; Hai, Tran; Leggewie, Christian C; Katzke, Nadine; La Cono, Violetta; Matesanz, Ruth; Jebbar, Mohamed; Jaeger, Karl-Erich; Yakimov, Michail M; Yakunin, Alexander F; Golyshin, Peter N; Golyshina, Olga V; Savchenko, Alexei; Ferrer, Manuel

    2015-02-01

    The present study provides a deeper view of protein functionality as a function of temperature, salt and pressure in deep-sea habitats. A set of eight different enzymes from five distinct deep-sea (3040-4908 m depth), moderately warm (14.0-16.5°C) biotopes, characterized by a wide range of salinities (39-348 practical salinity units), were investigated for this purpose. An enzyme from a 'superficial' marine hydrothermal habitat (65°C) was isolated and characterized for comparative purposes. We report here the first experimental evidence suggesting that in salt-saturated deep-sea habitats, the adaptation to high pressure is linked to high thermal resistance (P value = 0.0036). Salinity might therefore increase the temperature window for enzyme activity, and possibly microbial growth, in deep-sea habitats. As an example, Lake Medee, the largest hypersaline deep-sea anoxic lake of the Eastern Mediterranean Sea, where the water temperature is never higher than 16°C, was shown to contain halopiezophilic-like enzymes that are most active at 70°C and with denaturing temperatures of 71.4°C. The determination of the crystal structures of five proteins revealed unknown molecular mechanisms involved in protein adaptation to poly-extremes as well as distinct active site architectures and substrate preferences relative to other structurally characterized enzymes. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  4. Bacterial diversity and biogeochemistry of different chemosynthetic habitats of the REGAB cold seep (West African margin, 3160 m water depth

    Directory of Open Access Journals (Sweden)

    P. Pop Ristova

    2012-12-01

    Full Text Available The giant pockmark REGAB (West African margin, 3160 m water depth is an active methane-emitting cold seep ecosystem, where the energy derived from microbially mediated oxidation of methane supports high biomass and diversity of chemosynthetic communities. Bare sediments interspersed with heterogeneous chemosynthetic assemblages of mytilid mussels, vesicomyid clams and siboglinid tubeworms form a complex seep ecosystem. To better understand if benthic bacterial communities reflect the patchy distribution of chemosynthetic fauna, all major chemosynthetic habitats at REGAB were investigated using an interdisciplinary approach combining pore water geochemistry, in situ quantification of fluxes and consumption of methane, as well as bacterial community fingerprinting. This study revealed that sediments populated by different fauna assemblages show distinct biogeochemical activities and are associated with distinct sediment bacterial communities. The methane consumption rates and methane effluxes ranged over one to two orders of magnitude across habitats, and reached highest values at the mussel habitat, which hosted a different bacterial community compared to the other habitats. Clam assemblages had a profound impact on the sediment geochemistry, but less so on the bacterial community structure. Moreover, all clam assemblages at REGAB were restricted to sediments characterized by complete methane consumption in the seafloor, and intermediate biogeochemical activity. Overall, variations in the sediment geochemistry were reflected in the distribution of both fauna and microbial communities; and were mostly determined by methane flux.

  5. Biogeochemical signals from deep microbial life in terrestrial crust.

    Directory of Open Access Journals (Sweden)

    Yohey Suzuki

    Full Text Available In contrast to the deep subseafloor biosphere, a volumetrically vast and stable habitat for microbial life in the terrestrial crust remains poorly explored. For the long-term sustainability of a crustal biome, high-energy fluxes derived from hydrothermal circulation and water radiolysis in uranium-enriched rocks are seemingly essential. However, the crustal habitability depending on a low supply of energy is unknown. We present multi-isotopic evidence of microbially mediated sulfate reduction in a granitic aquifer, a representative of the terrestrial crust habitat. Deep meteoric groundwater was collected from underground boreholes drilled into Cretaceous Toki granite (central Japan. A large sulfur isotopic fractionation of 20-60‰ diagnostic to microbial sulfate reduction is associated with the investigated groundwater containing sulfate below 0.2 mM. In contrast, a small carbon isotopic fractionation (<30‰ is not indicative of methanogenesis. Except for 2011, the concentrations of H2 ranged mostly from 1 to 5 nM, which is also consistent with an aquifer where a terminal electron accepting process is dominantly controlled by ongoing sulfate reduction. High isotopic ratios of mantle-derived 3He relative to radiogenic 4He in groundwater and the flux of H2 along adjacent faults suggest that, in addition to low concentrations of organic matter (<70 µM, H2 from deeper sources might partly fuel metabolic activities. Our results demonstrate that the deep biosphere in the terrestrial crust is metabolically active and playing a crucial role in the formation of reducing groundwater even under low-energy fluxes.

  6. Non-cultural methods of human microflora evaluation for the benefit of crew medical control in confined habitat

    Science.gov (United States)

    Viacheslav, Ilyin; Lana, Moukhamedieva; Georgy, Osipov; Aleksey, Batov; Zoya, Soloviova; Robert, Mardanov; Yana, Panina; Anna, Gegenava

    2011-05-01

    Current control of human microflora is a great problem not only for the space medicine but also for practical health care. Due to many reasons its realization by classical bacteriological method is difficult in practical application or cannot be done. To evaluate non-cultural methods of microbial control of crews in a confined habitat we evaluated two different methods. The first method is based on digital treatment of microbial visual images, appearing after gram staining of microbial material from natural sample. This way the rate between gram-positive and gram-negative microbe could be gained as well as differentiation of rods and cocci could be attained, which is necessary for primary evaluation of human microbial cenosis in remote confined habitats. The other non-culture method of human microflora evaluation is gas chromatomass spectrometry (gcms) analysis of swabs gathered from different body sites. Gc-ms testing of swabs allows one to validate quantitative and special microflora based on specific lipid markers analysis.

  7. Timing of global regression and microbial bloom linked with the Permian-Triassic boundary mass extinction: implications for driving mechanisms

    Science.gov (United States)

    Baresel, Bjoern; Bucher, Hugo; Bagherpour, Borhan; Brosse, Morgane; Guodun, Kuang; Schaltegger, Urs

    2017-04-01

    High-precision U-Pb dating of single-zircon crystals by chemical abrasion-isotope dilution-thermal ionization mass spectrometry (CA-ID-TIMS) is applied to volcanic beds that are intercalated in sedimentary sequences across the Permian-Triassic boundary (PTB). By assuming that the zircon crystallization age closely approximate that of the volcanic eruption and subsequent deposition, U-Pb zircon geochronology is the preferred approach for dating abiotic and biotic events, such as the formational PTB and the Permian-Triassic boundary mass extinction (PTBME). We will present new U-Pb zircon dates for a series of volcanic ash beds in shallow-marine Permian-Triassic sections in the Nanpanjiang Basin, South China. These high-resolution U-Pb dates indicate a duration of 90 ± 38 kyr for the Permian sedimentary hiatus and a duration of 13 ± 57 kyr for the overlying Triassic microbial limestone in the shallow water settings of the Nanpanjiang pull apart Basin. The age and duration of the hiatus coincides with the formational PTB and the extinction interval in the Meishan Global Stratotype Section and Point, thus strongly supporting a glacio-eustatic regression, which best explains the genesis of the worldwide hiatus straddling the PTB in shallow water records. In adjacent deep marine troughs, rates of sediment accumulation display a six-fold decrease across the PTB compatible with a dryer and cooler climate during the Griesbachian as indicated by terrestrial plants. Our model of the PTBME hinges on the synchronicity of the hiatus with the onset of the Siberian Traps volcanism. This early eruptive phase likely released sulfur-rich volatiles into the stratosphere, thus simultaneously eliciting a short-lived ice age responsible for the global regression and a brief but intense acidification. Abrupt cooling, shrunk habitats on shelves and acidification may all have synergistically triggered the PTBME. Subsequently, the build-up of volcanic CO2 induced this transient cool

  8. Monitoring Microbially Influenced Corrosion

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    and diffusional effects and unreliable corrosion rates, when biofilm and ferrous sulphide corrosion products cover the steel surface. Corrosion rates can be overestimated by a factor of 10 to 100 by electrochemical techniques. Weight loss coupons and ER are recommended as necessary basic monitoring techniques......Abstract Microbially influenced corrosion (MIC) of carbon steel may occur in media with microbiological activity of especially sulphate-reducing bacteria (SRB). The applicability and reliability of a number of corrosion monitoring techniques for monitoring MIC has been evaluated in experiments....... EIS might be used for detection of MIC as the appearance of very large capacitances can be attributed to the combined ferrous sulphide and biofilm formation. Capacitance correlates directly with sulphide concentration in sterile sulphide media. Keywords: Corrosion monitoring, carbon steel, MIC, SRB...

  9. New microbial growth factor

    Science.gov (United States)

    Bok, S. H.; Casida, L. E., Jr.

    1977-01-01

    A screening procedure was used to isolate from soil a Penicillium sp., two bacterial isolates, and a Streptomyces sp. that produced a previously unknown microbial growth factor. This factor was an absolute growth requirement for three soil bacteria. The Penicillium sp. and one of the bacteria requiring the factor, an Arthrobacter sp., were selected for more extensive study concerning the production and characteristics of the growth factor. It did not seem to be related to the siderochromes. It was not present in soil extract, rumen fluid, or any other medium component tested. It appears to be a glycoprotein of high molecular weight and has high specific activity. When added to the diets for a meadow-vole mammalian test system, it caused an increased consumption of diet without a concurrent increase in rate of weight gain.

  10. Characterizing SI Engine Transient Fuel Consumption in ALPHA

    Science.gov (United States)

    Examine typical transient engine operation encountered over the EPA's vehicle and engine testing drive cycles to characterize that transient fuel usage, and then describe the changes made to ALPHA to better model transient engine operation.

  11. New developments in French transient monitoring: SYSFAC

    International Nuclear Information System (INIS)

    L'huby, Y.; Genette, P.; Faidy, C.; Kappler, F.; Balley, J.; Bimont, G.

    1991-01-01

    After more than ten years of experience with Transient Monitoring and Logging Procedure (TMLP) and six years of successfully experience with Fatiguemeters, EDF has decided to study a new concept of Fatigue Monitoring System: SYSFAC. This new automatic system which is developed to be operating in all the French PWR units is composed of three modules: mechanical transient logging, functional transient logging and fatiguemeters. This application must be connected to the on-site data acquisition system without complementary instrumentation on the plant. (author)

  12. Transient phenomena in electrical power systems

    CERN Document Server

    Venikov, V A; Higinbotham, W

    1964-01-01

    Electronics and Instrumentation, Volume 24: Transient Phenomena in Electrical Power Systems presents the methods for calculating the stability and the transient behavior of systems with forced excitation control. This book provides information pertinent to the analysis of transient phenomena in electro-mechanical systems.Organized into five chapters, this volume begins with an overview of the principal requirements in an excitation system. This text then explains the electromagnetic and electro-mechanical phenomena, taking into account the mutual action between the components of the system. Ot

  13. Transient analysis capabilities at ABB-CE

    International Nuclear Information System (INIS)

    Kling, C.L.

    1992-01-01

    The transient capabilities at ABB-Combustion Engineering (ABB-CE) Nuclear Power are a function of the computer hardware and related network used, the computer software that has evolved over the years, and the commercial technical exchange agreements with other related organizations and customers. ABB-CEA is changing from a mainframe/personal computer network to a distributed workstation/personal computer local area network. The paper discusses computer hardware, mainframe computing, personal computers, mainframe/personal computer networks, workstations, transient analysis computer software, design/operation transient analysis codes, safety (licensed) analysis codes, cooperation with ABB-Atom, and customer support

  14. Transient burnout in flow reduction condition

    International Nuclear Information System (INIS)

    Iwamura, Takamichi; Kuroyanagi, Toshiyuki

    1981-01-01

    A transient flow reduction burnout experiment was conducted with water in a uniformly heated, vertically oriented tube. Test pressures ranged from 0.5 to 3.9 MPa. An analytical method was developed to obtain transient burnout conditions at the exit. A simple correlation to predict the deviation of the transient burnout mass velocity at the tube exit from the steady state mass velocity obtained as a function of steam-water density ratio and flow reduction rate. The correlation was also compared with the other data. (author)

  15. Status of microbial diversity in agroforestry systems in Tamil Nadu, India.

    Science.gov (United States)

    Radhakrishnan, Srinivasan; Varadharajan, Mohan

    2016-06-01

    Soil is a complex and dynamic biological system. Agroforestry systems are considered to be an alternative land use option to help and prevent soil degradation, improve soil fertility, microbial diversity, and organic matter status. An increasing interest has emerged with respect to the importance of microbial diversity in soil habitats. The present study deals with the status of microbial diversity in agroforestry systems in Tamil Nadu. Eight soil samples were collected from different fields in agroforestry systems in Cuddalore, Villupuram, Tiruvanamalai, and Erode districts, Tamil Nadu. The number of microorganisms and physico-chemical parameters of soils were quantified. Among different microbial population, the bacterial population was recorded maximum (64%), followed by actinomycetes (23%) and fungi (13%) in different samples screened. It is interesting to note that the microbial population was positively correlated with the physico-chemical properties of different soil samples screened. Total bacterial count had positive correlation with soil organic carbon (C), moisture content, pH, nitrogen (N), and micronutrients such as Iron (Fe), copper (Cu), and zinc (Zn). Similarly, the total actinomycete count also showed positive correlations with bulk density, moisture content, pH, C, N, phosphorus (P), potassium (K), calcium (Ca), copper (Cu), magnesium (Mg), manganese (Mn), and zinc (Zn). It was also noticed that the soil organic matter, vegetation, and soil nutrients altered the microbial community under agroforestry systems. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Microbial diversity and carbon cycling in San Francisco Bay wetlands

    Energy Technology Data Exchange (ETDEWEB)

    Theroux, Susanna [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Hartman, Wyatt [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; He, Shaomei [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Univ. of Wisconsin, Madison, WI (United States); Tringe, Susannah [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.

    2014-03-21

    Wetland restoration efforts in San Francisco Bay aim to rebuild habitat for endangered species and provide an effective carbon storage solution, reversing land subsidence caused by a century of industrial and agricultural development. However, the benefits of carbon sequestration may be negated by increased methane production in newly constructed wetlands, making these wetlands net greenhouse gas (GHG) sources to the atmosphere. We investigated the effects of wetland restoration on below-ground microbial communities responsible for GHG cycling in a suite of historic and restored wetlands in SF Bay. Using DNA and RNA sequencing, coupled with real-time GHG monitoring, we profiled the diversity and metabolic potential of wetland soil microbial communities. The wetland soils harbor diverse communities of bacteria and archaea whose membership varies with sampling location, proximity to plant roots and sampling depth. Our results also highlight the dramatic differences in GHG production between historic and restored wetlands and allow us to link microbial community composition and GHG cycling with key environmental variables including salinity, soil carbon and plant species.

  17. Microbial diversity and stratification of South Pacific abyssal marine sediments.

    Science.gov (United States)

    Durbin, Alan M; Teske, Andreas

    2011-12-01

    Abyssal marine sediments cover a large proportion of the ocean floor, but linkages between their microbial community structure and redox stratification have remained poorly constrained. This study compares the downcore gradients in microbial community composition to porewater oxygen and nitrate concentration profiles in an abyssal marine sediment column in the South Pacific Ocean. Archaeal 16S rRNA clone libraries showed a stratified archaeal community that changed from Marine Group I Archaea in the aerobic and nitrate-reducing upper sediment column towards deeply branching, uncultured crenarchaeotal and euryarchaeotal lineages in nitrate-depleted, anaerobic sediment horizons. Bacterial 16S rRNA clone libraries revealed a similar shift on the phylum and subphylum level within the bacteria, from a complex community of Alpha-, Gamma- and Deltaproteobacteria, Actinobacteria and Gemmatimonadetes in oxic surface sediments towards uncultured Chloroflexi and Planctomycetes in the anaerobic sediment column. The distinct stratification of largely uncultured bacterial and archaeal groups within the oxic and nitrate-reducing marine sediment column provides initial constraints for their microbial habitat preferences. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

  18. Effects of Host Phylogeny and Habitats on Gut Microbiomes of Oriental River Prawn (Macrobrachium nipponense)

    Science.gov (United States)

    Chen, Po-Cheng; Weng, Francis Cheng-Hsuan; Jean, Wen Dar; Wang, Daryi

    2015-01-01

    The gut microbial community is one of the richest and most complex ecosystems on earth, and the intestinal microbes play an important role in host development and health. Next generation sequencing approaches, which rapidly produce millions of short reads that enable the investigation on a culture independent basis, are now popular for exploring microbial community. Currently, the gut microbiome in fresh water shrimp is unexplored. To explore gut microbiomes of the oriental river prawn (Macrobrachium nipponense) and investigate the effects of host genetics and habitats on the microbial composition, 454 pyrosequencing based on the 16S rRNA gene were performed. We collected six groups of samples, including M. nipponense shrimp from two populations, rivers and lakes, and one sister species (M. asperulum) as an out group. We found that Proteobacteria is the major phylum in oriental river prawn, followed by Firmicutes and Actinobacteria. Compositional analysis showed microbial divergence between the two shrimp species is higher than that between the two populations of one shrimp species collected from river and lake. Hierarchical clustering also showed that host genetics had a greater impact on the divergence of gut microbiome than host habitats. This finding was also congruent with the functional prediction from the metagenomic data implying that the two shrimp species still shared the same type of biological functions, reflecting a similar metabolic profile in their gut environments. In conclusion, this study provides the first investigation of the gut microbiome of fresh water shrimp, and supports the hypothesis of host species-specific signatures of bacterial community composition. PMID:26168244

  19. Molecular Analysis of Endolithic Microbial Communities in Volcanic Glasses

    Science.gov (United States)

    di Meo, C. A.; Giovannoni, S.; Fisk, M.

    2002-12-01

    Terrestrial and marine volcanic glasses become mineralogically and chemically altered, and in many cases this alteration has been attributed to microbial activity. We have used molecular techniques to study the resident microbial communities from three different volcanic environments that may be responsible for this crustal alteration. Total microbial DNA was extracted from rhyolite glass of the 7 million year old Rattlesnake Tuff in eastern Oregon. The DNA was amplified using the polymerase chain reaction (PCR) with bacterial primers targeting the 16S rRNA gene. This 16S rDNA was cloned and screened with restriction fragment length polymorphism (RFLP). Out of 89 total clones screened, 46 belonged to 13 different clone families containing two or more members, while 43 clones were unique. Sequences of eight clones representing the most dominant clone families in the library were 92 to 97% similar to soil bacterial species. In a separate study, young pillow basalts (rock- and seawater-associated archaea. The six rock community profiles were quite similar to each other, and the background water communities were also similar, respectively. Both the rock and water communities shared the same dominant peak. To identify the T-RFLP peaks corresponding to the individual members of the rock and seawater communities, clone libraries of the archaeal 16S rDNA for one basalt sample (Dive 3718) and its corresponding background water sample were constructed. The most abundant archaeal genes were closely related to uncultured Group I marine Crenarchaeota that have been previously identified from similar deep-sea habitats. These archaeal genes collectively correspond to the dominant T-RFLP peak present in both the rock and water samples. In a third study, we investigated the microbial community residing in a Hawaiian Scientific Drilling Program core collected near Hilo, Hawaii. Total microbial DNA was extracted from a depth of 1351 m in the drill core (ambient temperature in the

  20. The maturing of microbial ecology.

    Science.gov (United States)

    Schmidt, Thomas M

    2006-09-01

    A.J. Kluyver and C.B. van Niel introduced many scientists to the exceptional metabolic capacity of microbes and their remarkable ability to adapt to changing environments in The Microbe's Contribution to Biology. Beyond providing an overview of the physiology and adaptability of microbes, the book outlined many of the basic principles for the emerging discipline of microbial ecology. While the study of pure cultures was highlighted, provided a unifying framework for understanding the vast metabolic potential of microbes and their roles in the global cycling of elements, extrapolation from pure cultures to natural environments has often been overshadowed by microbiologists inability to culture many of the microbes seen in natural environments. A combination of genomic approaches is now providing a culture-independent view of the microbial world, revealing a more diverse and dynamic community of microbes than originally anticipated. As methods for determining the diversity of microbial communities become increasingly accessible, a major challenge to microbial ecologists is to link the structure of natural microbial communities with their functions. This article presents several examples from studies of aquatic and terrestrial microbial communities in which culture and culture-independent methods are providing an enhanced appreciation for the microbe's contribution to the evolution and maintenance of life on Earth, and offers some thoughts about the graduate-level educational programs needed to enhance the maturing field of microbial ecology.

  1. Global microbialization of coral reefs.

    Science.gov (United States)

    Haas, Andreas F; Fairoz, Mohamed F M; Kelly, Linda W; Nelson, Craig E; Dinsdale, Elizabeth A; Edwards, Robert A; Giles, Steve; Hatay, Mark; Hisakawa, Nao; Knowles, Ben; Lim, Yan Wei; Maughan, Heather; Pantos, Olga; Roach, Ty N F; Sanchez, Savannah E; Silveira, Cynthia B; Sandin, Stuart; Smith, Jennifer E; Rohwer, Forest

    2016-04-25

    Microbialization refers to the observed shift in ecosystem trophic structure towards higher microbial biomass and energy use. On coral reefs, the proximal causes of microbialization are overfishing and eutrophication, both of which facilitate enhanced growth of fleshy algae, conferring a competitive advantage over calcifying corals and coralline algae. The proposed mechanism for this competitive advantage is the DDAM positive feedback loop (dissolved organic carbon (DOC), disease, algae, microorganism), where DOC released by ungrazed fleshy algae supports copiotrophic, potentially pathogenic bacterial communities, ultimately harming corals and maintaining algal competitive dominance. Using an unprecedented data set of >400 samples from 60 coral reef sites, we show that the central DDAM predictions are consistent across three ocean basins. Reef algal cover is positively correlated with lower concentrations of DOC and higher microbial abundances. On turf and fleshy macroalgal-rich reefs, higher relative abundances of copiotrophic microbial taxa were identified. These microbial communities shift their metabolic potential for carbohydrate degradation from the more energy efficient Embden-Meyerhof-Parnas pathway on coral-dominated reefs to the less efficient Entner-Doudoroff and pentose phosphate pathways on algal-dominated reefs. This 'yield-to-power' switch by microorganism directly threatens reefs via increased hypoxia and greater CO2 release from the microbial respiration of DOC.

  2. Microbial biosensors for environmental monitoring

    Directory of Open Access Journals (Sweden)

    David VOGRINC

    2015-12-01

    Full Text Available Microbial biosensors are analytical devices capable of sensing substances in the environment due to the specific biological reaction of the microorganism or its parts. Construction of a microbial biosensor requires knowledge of microbial response to the specific analyte. Linking this response with the quantitative data, using a transducer, is the crucial step in the construction of a biosensor. Regarding the transducer type, biosensors are divided into electrochemical, optical biosensors and microbial fuel cells. The use of the proper configuration depends on the selection of the biosensing element. With the use of transgenic E. coli strains, bioluminescence or fluorescence based biosensors were developed. Microbial fuel cells enable the use of the heterogeneous microbial populations, isolated from wastewater. Different microorganisms are used for different pollutants – pesticides, heavy metals, phenolic compounds, organic waste, etc. Biosensing enables measurement of their concentration and their toxic or genotoxic effects on the microbes. Increasing environmental awareness has contributed to the increase of interest for biomonitoring. Although technologies, such as bioinformatics and genetic engineering, allow us to design complex and efficient microbial biosensors for environmental pollutants, the transfer of the laboratory work to the field still remains a problem to solve.

  3. Microbial electrode sensor for alcohols

    Energy Technology Data Exchange (ETDEWEB)

    Hikuma, M [Ajinomoto Co., Inc., Kawasaki, Japan; Kubo, T; Yasuda, T; Karube, I; Suzuki, S

    1979-10-01

    A microbial electrode consisting of immobilized microorganisms, a gas permeable Teflon membrane, and an oxygen electrode was prepared for the continuous determination of methyl and ethyl alcohols. Immobilized Trichosporon brassicae was employed for a microbial electrode sensor for ethyl alcohol. When a sample solution containing ethyl alcohol was injected into a microbial electrode system, the current of the electrode decreased markedly with time until a steady state was reached. The response time was within 10 min by the steady state method and within 6 min by the pulse method. A linear relationship was observed between the current decrease and the concentration of ethyl alcohol below 22.5 mg/liter. The current was reproducible within +- 6% of the relative error when a sample solution containing 16.5 mg/liter ethyl alcohol. The standard deviation was 0.5 mg/liter in 40 experiments. The selectivity of the microbial electrode sensor for ethyl alcohol was satisfactory. The microbial electrode sensor was applied to a fermentation broth of yeasts and satisfactory comparative results were obtained (correlation coefficient 0.98). The current output of the microbial electrode sensor was almost constant for more than three weeks and 2100 assays. A microbial electrode sensor using immobilized bacteria for methyl alcohol was also described.

  4. Salmon River Habitat Enhancement, 1984 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Konopacky, Richard C.

    1986-04-01

    This report has four volumes: a Tribal project annual report (Part 1) and three reports (Parts 2, 3, and 4) prepared for the Tribes by their engineering subcontractor. The Tribal project annual report contains reports for four subprojects within Project 83-359. Subproject I involved habitat and fish inventories in Bear Valley Creek, Valley County, Idaho that will be used to evaluate responses to ongoing habitat enhancement. Subproject II is the coordination/planning activities of the Project Leader in relation to other BPA-funded habitat enhancement projects that have or will occur within the traditional Treaty (Fort Bridger Treaty of 1868) fishing areas of the Shoshone-Bannock Tribes, Fort Hall Reservation, Idaho. Subproject III involved habitat and fish inventories (pretreatment) and habitat problem identification on the Yankee Fork of the Salmon River (including Jordan Creek). Subproject IV during 1985 involved habitat problem identification in the East Fork of the Salmon River and habitat and fish inventories (pretreatment) in Herd Creek, a tributary to the East Fork.

  5. Does learning or instinct shape habitat selection?

    Directory of Open Access Journals (Sweden)

    Scott E Nielsen

    Full Text Available Habitat selection is an important behavioural process widely studied for its population-level effects. Models of habitat selection are, however, often fit without a mechanistic consideration. Here, we investigated whether patterns in habitat selection result from instinct or learning for a population of grizzly bears (Ursus arctos in Alberta, Canada. We found that habitat selection and relatedness were positively correlated in female bears during the fall season, with a trend in the spring, but not during any season for males. This suggests that habitat selection is a learned behaviour because males do not participate in parental care: a genetically predetermined behaviour (instinct would have resulted in habitat selection and relatedness correlations for both sexes. Geographic distance and home range overlap among animals did not alter correlations indicating that dispersal and spatial autocorrelation had little effect on the observed trends. These results suggest that habitat selection in grizzly bears are partly learned from their mothers, which could have implications for the translocation of wildlife to novel environments.

  6. Microbial biofilms in water-mixed metalworking fluids; Mikrobielle Biofilme in wassergemischten Kuehlschmierstoffen

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Thomas [Wisura GmbH, Bremen (Germany)

    2013-05-15

    The microbial load of water-miscible metalworking fluids (MWF) as well as the hygienic aspects and the cost-related impact on the production process due to the activity of microbes is in the focus of many scientific investigations and documented in the related publications. The majority of this research work is focused on the microbiology of the water body, i.e. with the microbial life in the liquid coolant. The habitat biofilm, i.e. the three-dimensional growth of bacteria and fungi on surfaces of the coolant systems has been scarcely considered. Based on the scientific findings made in the recent years studying biofilms it can be concluded, that the relevant microbial processes for the depletion of the MWF and its recontamination takes predominantly places in biofilms. This paper gives an overview of the structure, the formation and the life in biofilms and represents their relevance in MWF systems. (orig.)

  7. Microbial community dynamics of an urban drinking water distribution system subjected to phases of chloramination and chlorination treatments.

    Science.gov (United States)

    Hwang, Chiachi; Ling, Fangqiong; Andersen, Gary L; LeChevallier, Mark W; Liu, Wen-Tso

    2012-11-01

    Water utilities in parts of the U.S. control microbial regrowth in drinking water distribution systems (DWDS) by alternating postdisinfection methods between chlorination and chloramination. To examine how this strategy influences drinking water microbial communities, an urban DWDS (population ≅ 40,000) with groundwater as the source water was studied for approximately 2 years. Water samples were collected at five locations in the network at different seasons and analyzed for their chemical and physical characteristics and for their microbial community composition and structure by examining the 16S rRNA gene via terminal restriction fragment length polymorphism and DNA pyrosequencing technology. Nonmetric multidimension scaling and canonical correspondence analysis of microbial community profiles could explain >57% of the variation. Clustering of samples based on disinfection types (free chlorine versus combined chlorine) and sampling time was observed to correlate to the shifts in microbial communities. Sampling location and water age (chlorinated water, and Methylophilaceae, Methylococcaceae, and Pseudomonadaceae were more abundant in chloraminated water. No correlation was observed with minor populations that were detected frequently (water and survived through the treatment process. Transient microbial populations including Flavobacteriaceae and Clostridiaceae were also observed. Overall, reversible shifts in microbial communities were especially pronounced with chloramination, suggesting stronger selection of microbial populations from chloramines than chlorine.

  8. The microbial ecology of permafrost

    DEFF Research Database (Denmark)

    Jansson, Janet; Tas, Neslihan

    2014-01-01

    Permafrost constitutes a major portion of the terrestrial cryosphere of the Earth and is a unique ecological niche for cold-adapted microorganisms. There is a relatively high microbial diversity in permafrost, although there is some variation in community composition across different permafrost......-gas emissions. This Review describes new data on the microbial ecology of permafrost and provides a platform for understanding microbial life strategies in frozen soil as well as the impact of climate change on permafrost microorganisms and their functional roles....

  9. Defining Disturbance for Microbial Ecology.

    Science.gov (United States)

    Plante, Craig J

    2017-08-01

    Disturbance can profoundly modify the structure of natural communities. However, microbial ecologists' concept of "disturbance" has often deviated from conventional practice. Definitions (or implicit usage) have frequently included climate change and other forms of chronic environmental stress, which contradict the macrobiologist's notion of disturbance as a discrete event that removes biomass. Physical constraints and disparate biological characteristics were compared to ask whether disturbances fundamentally differ in microbial and macroorganismal communities. A definition of "disturbance" for microbial ecologists is proposed that distinguishes from "stress" and other competing terms, and that is in accord with definitions accepted by plant and animal ecologists.

  10. simulation of electromagnetic transients in power systems

    African Journals Online (AJOL)

    Dr Obe

    1996-09-01

    Sep 1, 1996 ... Transients in power systems are initiated by abrupt changes to otherwise steady operating conditions. These changes would .... The method is applicable both to single transmission in real time. The method is applicable both ...

  11. The economic impact of reactor transients

    International Nuclear Information System (INIS)

    Rossin, A.D.; Vine, G.L.

    1984-01-01

    This chapter discusses the cost estimation of transients and the causal relationship between transients and accidents. It is suggested that the calculation of the actual cost of a transient that has occurred is impossible without computerized records. Six months of operating experience reports, based on a survey of pressurized water reactors (PWRs) and boiling water reactors (BWRs) conducted by the Nuclear Safety Analysis Center (NSAC), are analyzed. The significant costs of a reactor transient are the repair costs resulting from severe damage to plant equipment, the cost of scrams (the actions the system is designed to take to avoid safety risks), US NRC fines, negative publicity, utility rates and revenues. It is estimated that the Three Mile Island-2 accident cost the US over $100 billion in nuclear plant delays and cancellations, more expensive fuel, oil imports, backfits, bureaucratic, administrative and legal costs, and lost productivity

  12. Fuel cladding mechanical properties for transient analysis

    International Nuclear Information System (INIS)

    Johnson, G.D.; Hunter, C.W.; Hanson, J.E.

    1976-01-01

    Out-of-pile simulated transient tests have been conducted on irradiated fast-reactor fuel pin cladding specimens at heating rates of 10 0 F/s (5.6 0 K/s) and 200 0 F/s (111 0 K/s) to generate mechanical property information for use in describing cladding behavior during off-normal events. Mechanical property data were then analyzed, applying the Larson-Miller Parameter to the effects of heating rate and neutron fluence. Data from simulated transient tests on TREAT-tested fuel pins demonstrate that Plant Protective System termination of 3$/s transients prevents significant damage to cladding. The breach opening produced during simulated transient testing is shown to decrease in size with increasing neutron fluence

  13. Detection of Transient Signals in Doppler Spectra

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Signal processing is used to detect transient signals in the presence of noise. Two embodiments are disclosed. In both embodiments, the time series from a remote...

  14. Transient management using the safety function approach

    International Nuclear Information System (INIS)

    Corcoran, W.R.; Barrow, J.H.; Bischoff, G.C.; Callaghan, V.M.; Pearce, R.T.

    1984-01-01

    The safety function approach is described. Its use in the development of a transient management procedures system includes optimal recovery procedures tailored to specific, anticipated symptom sets and a functional recovery procedure which is more general. Simulator evaluations are described

  15. Development of a transient criticality evaluation method

    International Nuclear Information System (INIS)

    Pain, C.C.; Eaton, M.D.; Miles, B.; Ziver, A.K.; Gomes, J.L.M.A.; Umpleby, A.P.; Piggott, M.D.; Goddard, A.J.H.; Oliveira, C.R.E. de

    2005-01-01

    In developing a transient criticality evaluation method we model, in full spatial/temporal detail, the neutron fluxes and consequent power and the evolving material properties - their flows, energies, phase changes etc. These methods are embodied in the generic method FETCH code which is based as far as possible on basic principles and is capable of use in exploring safety-related situations somewhat beyond the range of experiment. FETCH is a general geometry code capable of addressing a range of criticality issues in fissile materials. The code embodies both transient radiation transport and transient fluid dynamics. Work on powders, granular materials, porous media and solutions is reviewed. The capability for modelling transient criticality for chemical plant, waste matrices and advanced reactors is also outlined. (author)

  16. RFSP simulations of Darlington FINCH refuelling transient

    International Nuclear Information System (INIS)

    Carruthers, E.V.; Chow, H.C.

    1997-01-01

    Immediately after refuelling of a channel, the fresh bundles are free of fission products. Xenon-135, the most notable of the saturating fission products, builds up to an equilibrium level in about 30 h. The channel power of the refuelled channel would therefore initially peak and then drop to a steady-state level. The RFSP code can track saturating-fission-product transients and power transients. The Fully INstrumented CHannels (FINCHs) in Darlington NGS provides channel power data on the refuelling power transients. In this paper, such data has been used to identify the physical evidence of the fission-product transient effect on channel power, and to validate RFSP fission-product-driver calculation results. (author)

  17. Climatic feedbacks between stationary and transient eddies

    International Nuclear Information System (INIS)

    Branscome, L.E.

    1994-01-01

    Stationary eddies make a significant contribution to poleward heat transport during Northern Hemisphere winter, equaling the transport by transient eddies. On the other hand, stationary eddy transport during the summer is negligible. The effect of topography on time-mean stationary waves and low-frequency variability has been widely studied. In contrast, little attention has been given to the climatic feedbacks associated with stationary eddies. Furthermore, the relationship between stationary and transient eddies in the context of global and regional climate is not well understood. The response of the climate system to anthropogenic forcing is likely to have some dependence on stationary wave transport and its interaction with transient eddies. Some early GCM simulations and observational analyses indicate a strong feedback between the meridional heat fluxes of stationary and transient eddies

  18. Acoustic Transient Source Localization From an Aerostat

    National Research Council Canada - National Science Library

    Scanlon, Michael; Reiff, Christian; Noble, John

    2006-01-01

    The Army Research Laboratory (ARL) has conducted experiments using acoustic sensor arrays suspended below tethered aerostats to detect and localize transient signals from mortars, artillery and small arms fire...

  19. Attosecond transient absorption spectroscopy of molecular hydrogen

    International Nuclear Information System (INIS)

    Martín, Fernando; González-Castrillo, Alberto; Palacios, Alicia; Argenti, Luca; Cheng, Yan; Chini, Michael; Wang, Xiaowei; Chang, Zenghu

    2015-01-01

    We extend attosecond transient absorption spectroscopy (ATAS) to the study of hydrogen molecules, demonstrating the potential of the technique to resolve – simultaneously and with state resolution – both the electronic and nuclear dynamics. (paper)

  20. Cable system transients theory, modeling and simulation

    CERN Document Server

    Ametani, Akihiro; Nagaoka, Naoto

    2015-01-01

    A systematic and comprehensive introduction to electromagnetic transient in cable systems, written by the internationally renowned pioneer in this field Presents a systematic and comprehensive introduction to electromagnetic transient in cable systems Written by the internationally renowned pioneer in the field Thorough coverage of the state of the art on the topic, presented in a well-organized, logical style, from fundamentals and practical applications A companion website is available

  1. Partial discharge transients: The field theoretical approach

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson; Crichton, George C

    1998-01-01

    Up until the mid-1980s the theory of partial discharge transients was essentially static. This situation had arisen because of the fixation with the concept of void capacitance and the use of circuit theory to address what is in essence a field problem. Pedersen rejected this approach and instead...... began to apply field theory to the problem of partial discharge transients. In the present paper, the contributions of Pedersen using the field theoretical approach will be reviewed and discussed....

  2. Atucha I nuclear power plant transients analysis

    International Nuclear Information System (INIS)

    Castano, J.; Schivo, M.

    1987-01-01

    A program for the transients simulation thermohydraulic calculation without loss of coolant (KWU-ENACE development) to evaluate Atucha I nuclear power plant behaviour is used. The program includes systems simulation and nuclear power plants control bonds with real parameters. The calculation results show a good agreement with the output 'protocol' of various transients of the nuclear power plant, keeping the error, in general, lesser than ± 10% from the variation of the nuclear power plant's state variables. (Author)

  3. PC-Reactor-core transient simulation code

    International Nuclear Information System (INIS)

    Nakata, H.

    1989-10-01

    PC-REATOR, a reactor core transient simulation code has been developed for the real-time operator training on a IBM-PC microcomputer. The program presents capabilities for on-line exchange of the operating parameters during the transient simulation, by friendly keyboard instructions. The model is based on the point-kinetics approximation, with 2 delayed neutron percursors and up to 11 decay power generating groups. (author) [pt

  4. Modeling of Transients in an Enrichment Circuit

    International Nuclear Information System (INIS)

    Fernandino, Maria; Delmastro, Dario; Brasnarof, Daniel

    2003-01-01

    In the present work a mathematical model is presented in order to describe the dynamic behavior inside a closed enrichment loop, the latter representing a single stage of an uranium gaseous diffusion enrichment cascade.The analytical model is turned into a numerical model, and implemented through a computational code.Transients of two species separation were numerically analyzed, including setting times of each magnitude, behavior of each one of them during different transients, and redistribution of concentrations along the closed loop

  5. Transient Exciplex Formation Electron Transfer Mechanism

    OpenAIRE

    Michael G. Kuzmin; Irina V. Soboleva; Elena V. Dolotova

    2011-01-01

    Transient exciplex formation mechanism of excited-state electron transfer reactions is analyzed in terms of experimental data on thermodynamics and kinetics of exciplex formation and decay. Experimental profiles of free energy, enthalpy, and entropy for transient exciplex formation and decay are considered for several electron transfer reactions in various solvents. Strong electronic coupling in contact pairs of reactants causes substantial decrease of activation energy relative to that for c...

  6. Microbial ecology-based engineering of Microbial Electrochemical Technologies.

    Science.gov (United States)

    Koch, Christin; Korth, Benjamin; Harnisch, Falk

    2018-01-01

    Microbial ecology is devoted to the understanding of dynamics, activity and interaction of microorganisms in natural and technical ecosystems. Bioelectrochemical systems represent important technical ecosystems, where microbial ecology is of highest importance for their function. However, whereas aspects of, for example, materials and reactor engineering are commonly perceived as highly relevant, the study and engineering of microbial ecology are significantly underrepresented in bioelectrochemical systems. This shortfall may be assigned to a deficit on knowledge and power of these methods as well as the prerequisites for their thorough application. This article discusses not only the importance of microbial ecology for microbial electrochemical technologies but also shows which information can be derived for a knowledge-driven engineering. Instead of providing a comprehensive list of techniques from which it is hard to judge the applicability and value of information for a respective one, this review illustrates the suitability of selected techniques on a case study. Thereby, best practice for different research questions is provided and a set of key questions for experimental design, data acquisition and analysis is suggested. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  7. Subtle shifts in microbial communities occur alongside the release of carbon induced by drought and rewetting in contrasting peatland ecosystems.

    Science.gov (United States)

    Potter, Caitlin; Freeman, Chris; Golyshin, Peter N; Ackermann, Gail; Fenner, Nathalie; McDonald, James E; Ehbair, Abdassalam; Jones, Timothy G; Murphy, Loretta M; Creer, Simon

    2017-09-12

    Peat represents a globally significant pool of sequestered carbon. However, peatland carbon stocks are highly threatened by anthropogenic climate change, including drought, which leads to a large release of carbon dioxide. Although the enzymatic mechanisms underlying drought-driven carbon release are well documented, the effect of drought on peatland microbial communities has been little studied. Here, we carried out a replicated and controlled drought manipulation using intact peat 'mesocosm cores' taken from bog and fen habitats, and used a combination of community fingerprinting and sequencing of marker genes to identify community changes associated with drought. Community composition varied with habitat and depth. Moreover, community differences between mesocosm cores were stronger than the effect of the drought treatment, emphasising the importance of replication in microbial marker gene studies. While the effect of drought on the overall composition of prokaryotic and eukaryotic communities was weak, a subset of the microbial community did change in relative abundance, especially in the fen habitat at 5 cm depth. 'Drought-responsive' OTUs were disproportionately drawn from the phyla Bacteroidetes and Proteobacteria. Collectively, the data provide insights into the microbial community changes occurring alongside drought-driven carbon release from peatlands, and suggest a number of novel avenues for future research.

  8. Transient ischemic attack presenting in an elderly patient with transient ophthalmic manifestations

    Directory of Open Access Journals (Sweden)

    Sparshi Jain

    2016-01-01

    Full Text Available Transient ischemic attack (TIA is a transient neurological deficit of cerebrovascular origin without infarction which may last only for a short period and can have varying presentations. We report a case of 58-year-old male with presenting features of sudden onset transient vertical diplopia and transient rotatory nystagmus which self-resolved within 12 h. Patient had no history of any systemic illness. On investigating, hematological investigations and neuroimaging could not explain these sudden and transient findings. A TIA could possibly explain these sudden and transient ocular findings in our patient. This case report aims to highlight the importance of TIA for ophthalmologists. We must not ignore these findings as these could be warning signs of an impending stroke which may or may not be detected on neuroimaging. Thus, early recognition, primary prevention strategies, and timely intervention are needed.

  9. Gulf-Wide Information System, Environmental Sensitivity Index Habitats Database, Geographic NAD83, LDWF (2001) [esi_habitats_LDWF_2001

    Data.gov (United States)

    Louisiana Geographic Information Center — This data set contains sensitive biological resource data for coastal habitats in Louisiana. Vector polygons represent various habitats, including marsh types, other...

  10. Flow transients experiments with refrigerant-12

    International Nuclear Information System (INIS)

    Celata, G.P.; D'Annibale, F.; Farello, G.E.; Setaro, T.

    1986-01-01

    Flow transients have been investigated in a wide range of thermal-hydraulics situations with Refrigerannt-12. Six pressures (including the reference to PWR and BWR characteristic liquid to vapour densities ratios), several periods of the flowrate transients coastdown during the simulated flow decays, and different specific mass flowrate have been studied emploiyng a circular duct test section (Dsub(i)=7,5 mm). Two heated lengths of the test section have been considered (L = 2300 and 1180 mm). Experimental data have shown the complete inadequacy of steady-state critical heat flux correlations in predicting the onset of boiling crisis during fast flow transients (half-flow decay time, tsub(h)lt5.0-6.0 s). The flow transient does not show dependence, in terms of DNB conditions ,upon the length of the test section: the ratio between transient and steady-state critical mass flowrate is not dependent on the tested geometry. The time interval from the start of the flowrate transient to the onset of DNB (time to crisis), has been experimentally determined for all the runs. Data analysis for a better theoretical prediction of the phenomenon has been accomplished, and a design correlation for DNB conditons and time to crisis prediction has been proposed

  11. Microbial Cell Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Doktycz, Mitchel John [ORNL; Sullivan, Claretta [Eastern Virginia Medical School; Mortensen, Ninell P [ORNL; Allison, David P [ORNL

    2011-01-01

    limitation on the maximum scan size (roughly 100 x 100 {mu}m) and the restricted movement of the cantilever in the Z (or height) direction. In most commercial AFMs, the Z range is restricted to roughly 10 {mu}m such that the height of cells to be imaged must be seriously considered. Nevertheless, AFM can provide structural-functional information at nanometer resolution and do so in physiologically relevant environments. Further, instrumentation for scanning probe microscopy continues to advance. Systems for high-speed imaging are becoming available, and techniques for looking inside the cells are being demonstrated. The ability to combine AFM with other imaging modalities is likely to have an even greater impact on microbiological studies. AFM studies of intact microbial cells started to appear in the literature in the 1990s. For example, AFM studies of Saccharomyces cerevisiae examined buddings cars after cell division and detailed changes related to cell growth processes. Also, the first AFM studies of bacterial biofilms appeared. In the late 1990s, AFM studies of intact fungal spores described clear changes in spore surfaces upon germination, and studies of individual bacterial cells were also described. These early bacterial imaging studies examined changes in bacterial morphology due to antimicrobial peptides exposure and bacterial adhesion properties. The majority of these early studies were carried out on dried samples and took advantage of the resolving power of AFM. The lack of cell mounting procedures presented an impediment for cell imaging studies. Subsequently, several approaches to mounting microbial cells have been developed, and these techniques are described later. Also highlighted are general considerations for microbial imaging and a description of some of the various applications of AFM to microbiology.

  12. MICROBIAL MATS - A JOINT VENTURE

    NARCIS (Netherlands)

    VANGEMERDEN, H

    Microbial mats characteristically are dominated by a few functional groups of microbes: cyanobacteria, colorless sulfur bacteria, purple sulfur bacteria, and sulfate-reducing bacteria. Their combined metabolic activities result in steep environmental microgradients, particularly of oxygen and

  13. Microbial production of gaseous hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, Hideo

    1987-10-20

    Microbial production of ethylene, isobutane and a saturated gaseous hydrocarbon mixture was described. Microbial ethylene production was studied with Penicillium digitatum IFO 9372 and a novel pathway of the ethylene biosynthesis through alpha-ketoglutarate was proposed. Rhodotorula minuta IFO 1102 was selected for the microbial production of isobutane and the interesting actions of L-leucine and L-phenylalanine for the isobutane production were found. It was finally presented about the microbial production of a saturated gaseous hydrocarbon mixture with Rhizopus japonicus IFO 4758 was described. A gas mixture was produced through a chemical reaction of SH compounds and some cellular component such as squalene under aerobic conditions. (4 figs, 7 tabs, 41 refs)

  14. Seasonality in ocean microbial communities.

    Science.gov (United States)

    Giovannoni, Stephen J; Vergin, Kevin L

    2012-02-10

    Ocean warming occurs every year in seasonal cycles that can help us to understand long-term responses of plankton to climate change. Rhythmic seasonal patterns of microbial community turnover are revealed when high-resolution measurements of microbial plankton diversity are applied to samples collected in lengthy time series. Seasonal cycles in microbial plankton are complex, but the expansion of fixed ocean stations monitoring long-term change and the development of automated instrumentation are providing the time-series data needed to understand how these cycles vary across broad geographical scales. By accumulating data and using predictive modeling, we gain insights into changes that will occur as the ocean surface continues to warm and as the extent and duration of ocean stratification increase. These developments will enable marine scientists to predict changes in geochemical cycles mediated by microbial communities and to gauge their broader impacts.

  15. Manor gardens: Harbors of local natural habitats?

    Czech Academy of Sciences Publication Activity Database

    Šantrůčková, M.; Demková, K.; Dostálek, J.; Frantík, Tomáš

    2017-01-01

    Roč. 205, JAN 2017 (2017), s. 16-22 ISSN 0006-3207 Institutional support: RVO:67985939 Keywords : park * human impact * habitat network Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 4.022, year: 2016

  16. habitat are of special scientific, educative and

    African Journals Online (AJOL)

    Dr Osondu

    Over 50% of all sightings were achieved in the matured forest. Keywords: ... hotspots, eco- tourism potential for game viewing, ... conservation is the increasing rate of habitat loss or ... to relatively undisturbed natural areas for educational,.

  17. Expandable Habitat Outfit Structures, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Topic H3.01 captures the need for robust, multipurpose deployable structures with high packing efficiencies for next generation orbital habitats. Multiple launch and...

  18. Self-Deploying, Composite Habitats, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Cornerstone Research Group, Inc. (CRG), proposes to develop self-deploying, composite structures for lunar habitats, based on CRG's VeritexTM materials. These...

  19. Habitat Mapping Cruise (HB0805, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Objectives are to: 1) perform multibeam mapping of transitional and deepwater habitats in Hudson Canyon (off New Jersey) with the National Institute of Undersea...

  20. Klawock Lagoon, Alaska Benthic Habitats 2011 Geoform

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Klawock River on Alaska's Prince of Wales Island drains a 29,061 acre watershed with 132 miles of streambed habitat supporting seven salmon and trout species....

  1. Klawock Lagoon, Alaska Benthic Habitats 2011 Substrate

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Klawock River on Alaska's Prince of Wales Island drains a 29,061 acre watershed with 132 miles of streambed habitat supporting seven salmon and trout species....

  2. Elkhorn and Staghorn Corals Critical Habitat

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data represent the critical habitat for elkhorn coral (Acropora palmata) and staghorn coral (A. cervicornis) as designated by 73 FR 72210, November 26, 2008,...

  3. Klawock Lagoon, Alaska Benthic Habitats 2011 Geodatabase

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Klawock River on Alaska's Prince of Wales Island drains a 29,061 acre watershed with 132 miles of streambed habitat supporting seven salmon and trout species....

  4. Deep-Sea Soft Coral Habitat Suitability

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Deep-sea corals, also known as cold water corals, create complex communities that provide habitat for a variety of invertebrate and fish species, such as grouper,...

  5. Avian Habitat Data; Seward Peninsula, Alaska, 2012

    Data.gov (United States)

    Department of the Interior — This data product contains avian habitat data collected on the Seward Peninsula, Alaska, USA, during 21 May – 10 June 2012. We conducted replicated 10-min surveys...

  6. Klawock Lagoon, Alaska Benthic Habitats 2011 Biotic

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Klawock River on Alaska's Prince of Wales Island drains a 29,061 acre watershed with 132 miles of streambed habitat supporting seven salmon and trout species....

  7. Movements and habitat utilization of nembwe, Serranochromis ...

    African Journals Online (AJOL)

    distance migrations onto the floodplains. It is concluded that although staying within relatively small home ranges, nembwe appears as a species with a variable and flexible habitat utilization. Keywords: fish, radio-tagging, telemetry, home range ...

  8. Deep-Sea Stony Coral Habitat Suitability

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Deep-sea corals, also known as cold water corals, create complex communities that provide habitat for a variety of invertebrate and fish species, such as grouper,...

  9. Microbial safety of foods

    International Nuclear Information System (INIS)

    Bandekar, J.R.

    2013-01-01

    Despite advances in hygiene, consumer knowledge and food treatment and processing, food-borne diseases have become one of the most widespread public health problems in the world to-day. About two thirds of all outbreaks are traced to microbial contaminated food - one of the most hazardous being Clostridium botulinum, E. coli 0157: H7 and Salmonella. The pathogens can be introduced in the food products anywhere in the food chain and hence it is of prime important to have microbial vigilance in the entire food chain. WHO estimates that food-borne and water-borne diarrhoeal diseases taken together kill about 2.2 million people annually. The infants, children, elderly and immune-compromised people are particularly susceptible to food-borne diseases. Unsafe food causes many acute and life-long diseases, ranging from diarrhoeal diseases to various forms of cancer. A number of factors such as emergence of new food-borne pathogens, development of drug resistance in the pathogens, changing life style, global trade of food etc. are responsible for the continued persistence of food-borne diseases. Due to consumer demand, a number of Ready-To-Eat (RTE) minimally processed foods are increasingly marketed. However, there is increased risk of food-borne diseases with these products. The food-borne disease outbreaks due to E. coli O157:H7, Listeria monocytogenes, Salmonella and Campylobacter are responsible for recall of many foods resulting in heavy losses to food industry. The development of multi drug resistant pathogens due to indiscriminate use of antibiotics is also a major problem. Food Technology Division of Bhabha Atomic Research Centre has been working on food-borne bacterial pathogens particularly Salmonella, Campylobacter, Vibrio and Aeromonas species, their prevalence in export quality seafood as well in foods sold in retail market such as poultry, fish, sprouts and salads. These pathogens from Indian foods have been characterized for the presence of virulence genes

  10. Microbially mediated mineral carbonation

    Science.gov (United States)

    Power, I. M.; Wilson, S. A.; Dipple, G. M.; Southam, G.

    2010-12-01

    Mineral carbonation involves silicate dissolution and carbonate precipitation, which are both natural processes that microorganisms are able to mediate in near surface environments (Ferris et al., 1994; Eq. 1). (Ca,Mg)SiO3 + 2H2CO3 + H2O → (Ca,Mg)CO3 + H2O + H4SiO4 + O2 (1) Cyanobacteria are photoautotrophs with cell surface characteristics and metabolic processes involving inorganic carbon that can induce carbonate precipitation. This occurs partly by concentrating cations within their net-negative cell envelope and through the alkalinization of their microenvironment (Thompson & Ferris, 1990). Regions with mafic and ultramafic bedrock, such as near Atlin, British Columbia, Canada, represent the best potential sources of feedstocks for mineral carbonation. The hydromagnesite playas near Atlin are a natural biogeochemical model for the carbonation of magnesium silicate minerals (Power et al., 2009). Field-based studies at Atlin and corroborating laboratory experiments demonstrate the ability of a microbial consortium dominated by filamentous cyanobacteria to induce the precipitation of carbonate minerals. Phototrophic microbes, such as cyanobacteria, have been proposed as a means for producing biodiesel and other value added products because of their efficiency as solar collectors and low requirement for valuable, cultivable land in comparison to crops (Dismukes et al., 2008). Carbonate precipitation and biomass production could be facilitated using specifically designed ponds to collect waters rich in dissolved cations (e.g., Mg2+ and Ca2+), which would allow for evapoconcentration and provide an appropriate environment for growth of cyanobacteria. Microbially mediated carbonate precipitation does not require large quantities of energy or chemicals needed for industrial systems that have been proposed for rapid carbon capture and storage via mineral carbonation (e.g., Lackner et al., 1995). Therefore, this biogeochemical approach may represent a readily

  11. Subseafloor basalts as fungal habitats

    Science.gov (United States)

    Ivarsson, M.; Bengtson, S.

    2013-12-01

    The oceanic crust makes up the largest potential habitat for life on Earth, yet next to nothing is known about the abundance, diversity and ecology of its biosphere. Our understanding of the deep biosphere of subseafloor crust is, with a few exceptions, based on a fossil record. Surprisingly, a majority of the fossilized microorganisms have been interpreted or recently re-interpreted as remnants of fungi rather than prokaryotes. Even though this might be due to a bias in fossilization the presence of fungi in these settings can not be neglected. We have examined fossilized microorganisms in drilled basalt samples collected at the Emperor Seamounts in the Pacific Ocean. Synchrotron-radiation X-ray tomography microscopy (SRXTM) studies has revealed a complex morphology and internal structure that corresponds to characteristic fungal morphology. Chitin was detected in the fossilized hyphae, which is another strong argument in favour of a fungal interpretation. Chitin is absent in prokaryotes but a substantial constituent in fungal cell walls. The fungal colonies consist of both hyphae and yeast-like growth states as well as resting structures and possible fruit bodies, thus, the fungi exist in vital colonies in subseafloor basalts. The fungi have also been involved in extensive weathering of secondary mineralisations. In terrestrial environments fungi are known as an important geobiological agent that promotes mineral weathering and decomposition of organic matter, and they occur in vital symbiosis with other microorganisms. It is probable to assume that fungi would play a similar role in subseafloor basalts and have great impact on the ecology and on biogeochemical cycles in such environments.

  12. Transient negative biochar effects on plant growth are strongest after microbial species loss

    NARCIS (Netherlands)

    Hol, (Gera) W.H.G.; Vestergård, M.; Ten Hooven, F.C.; Duyts, H.; Van de Voorde, T.F.J.; Bezemer, T. Martijn

    2017-01-01

    Biochar has been explored as an organic amendment to improve soil quality and benefit plant growth. The overall positive effects of biochar on crop yields are generally attributed to abiotic changes, while the alternative causal pathway via changes in soil biota is unexplored. We compared plant

  13. Contaminant immobilization via microbial activity

    International Nuclear Information System (INIS)

    1991-11-01

    The aim of this study was to search the literature to identify biological techniques that could be applied to the restoration of contaminated groundwaters near uranium milling sites. Through bioremediation it was hypothesized that the hazardous heavy metals could be immobilized in a stable, low-solubility form, thereby halting their progress in the migrating groundwater. Three basic mechanisms were examined: reduction of heavy metals by microbially produced hydrogen sulfide; direct microbial mediated reduction; and biosorption

  14. Microbial genomes: Blueprints for life

    Energy Technology Data Exchange (ETDEWEB)

    Relman, David A.; Strauss, Evelyn

    2000-12-31

    Complete microbial genome sequences hold the promise of profound new insights into microbial pathogenesis, evolution, diagnostics, and therapeutics. From these insights will come a new foundation for understanding the evolution of single-celled life, as well as the evolution of more complex life forms. This report is an in-depth analysis of scientific issues that provides recommendations and will be widely disseminated to the scientific community, federal agencies, industry and the public.

  15. Chronic alcoholism and microbial keratitis.

    OpenAIRE

    Ormerod, L. D.; Gomez, D. S.; Schanzlin, D. J.; Smith, R. E.

    1988-01-01

    In a series of 227 consecutive, non-referred patients with microbial keratitis an analysis of the accumulated hospital records showed that one-third were associated with chronic alcoholism. The diagnosis of alcoholism was usually unsuspected on admission to hospital. The microbial pathogenesis in these patients was distinctive; coagulase-negative staphylococci, alpha- and beta-streptococci, moraxellae, enteric Gram-negative bacilli, and polymicrobial infections were unusually prominent. Pseud...

  16. Columbia County Habitat for Humanity Passive Townhomes

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2016-03-01

    Columbia County Habitat for Humanity (CCHH) (New York, Climate Zone 5A) built a pair of townhomes to Passive House Institute U.S. (PHIUS+ 2015) criteria to explore approaches for achieving Passive House performance (specifically with respect to exterior wall, space-conditioning, and ventilation strategies) within the labor and budget context inherent in a Habitat for Humanity project. CCHH’s goal is to eventually develop a cost-justified Passive House prototype design for future projects.

  17. Soil microbial biomass, activity and community composition along altitudinal gradients in the High Arctic (Billefjorden, Svalbard

    Directory of Open Access Journals (Sweden)

    P. Kotas

    2018-03-01

    Full Text Available The unique and fragile High Arctic ecosystems are vulnerable to global climate warming. The elucidation of factors driving microbial distribution and activity in arctic soils is essential for a comprehensive understanding of ecosystem functioning and its response to environmental change. The goals of this study were to investigate microbial biomass and activity, microbial community structure (MCS, and their environmental controls in soils along three elevational transects in the coastal mountains of Billefjorden, central Svalbard. Soils from four different altitudes (25, 275, 525 and 765 m above sea level were analyzed for a suite of characteristics including temperature regimes, organic matter content, base cation availability, moisture, pH, potential respiration, and microbial biomass and community structure using phospholipid fatty acids (PLFAs. We observed significant spatial heterogeneity of edaphic properties among transects, resulting in transect-specific effects of altitude on most soil parameters. We did not observe any clear elevation pattern in microbial biomass, and microbial activity revealed contrasting elevational patterns between transects. We found relatively large horizontal variability in MCS (i.e., between sites of corresponding elevation in different transects, mainly due to differences in the composition of bacterial PLFAs, but also a systematic altitudinal shift in MCS related to different habitat preferences of fungi and bacteria, which resulted in high fungi-to-bacteria ratios at the most elevated sites. The biological soil crusts on these most elevated, unvegetated sites can host microbial assemblages of a size and activity comparable to those of the arctic tundra ecosystem. The key environmental factors determining horizontal and vertical changes in soil microbial properties were soil pH, organic carbon content, soil moisture and Mg2+ availability.

  18. Differential sensitivity of total and active soil microbial communities to drought and forest management.

    Science.gov (United States)

    Bastida, Felipe; Torres, Irene F; Andrés-Abellán, Manuela; Baldrian, Petr; López-Mondéjar, Rubén; Větrovský, Tomáš; Richnow, Hans H; Starke, Robert; Ondoño, Sara; García, Carlos; López-Serrano, Francisco R; Jehmlich, Nico

    2017-10-01

    Climate change will affect semiarid ecosystems through severe droughts that increase the competition for resources in plant and microbial communities. In these habitats, adaptations to climate change may consist of thinning-that reduces competition for resources through a decrease in tree density and the promotion of plant survival. We deciphered the functional and phylogenetic responses of the microbial community to 6 years of drought induced by rainfall exclusion and how forest management affects its resistance to drought, in a semiarid forest ecosystem dominated by Pinus halepensis Mill. A multiOMIC approach was applied to reveal novel, community-based strategies in the face of climate change. The diversity and the composition of the total and active soil microbiome were evaluated by 16S rRNA gene (bacteria) and ITS (fungal) sequencing, and by metaproteomics. The microbial biomass was analyzed by phospholipid fatty acids (PLFAs), and the microbially mediated ecosystem multifunctionality was studied by the integration of soil enzyme activities related to the cycles of C, N, and P. The microbial biomass and ecosystem multifunctionality decreased in drought-plots, as a consequence of the lower soil moisture and poorer plant development, but this decrease was more notable in unthinned plots. The structure and diversity of the total bacterial community was unaffected by drought at phylum and order level, but did so at genus level, and was influenced by seasonality. However, the total fungal community and the active microbial community were more sensitive to drought and were related to ecosystem multifunctionality. Thinning in plots without drought increased the active diversity while the total diversity was not affected. Thinning promoted the resistance of ecosystem multifunctionality to drought through changes in the active microbial community. The integration of total and active microbiome analyses avoids misinterpretations of the links between the soil microbial

  19. Soil microbial biomass, activity and community composition along altitudinal gradients in the High Arctic (Billefjorden, Svalbard)

    Science.gov (United States)

    Kotas, Petr; Šantrůčková, Hana; Elster, Josef; Kaštovská, Eva

    2018-03-01

    The unique and fragile High Arctic ecosystems are vulnerable to global climate warming. The elucidation of factors driving microbial distribution and activity in arctic soils is essential for a comprehensive understanding of ecosystem functioning and its response to environmental change. The goals of this study were to investigate microbial biomass and activity, microbial community structure (MCS), and their environmental controls in soils along three elevational transects in the coastal mountains of Billefjorden, central Svalbard. Soils from four different altitudes (25, 275, 525 and 765 m above sea level) were analyzed for a suite of characteristics including temperature regimes, organic matter content, base cation availability, moisture, pH, potential respiration, and microbial biomass and community structure using phospholipid fatty acids (PLFAs). We observed significant spatial heterogeneity of edaphic properties among transects, resulting in transect-specific effects of altitude on most soil parameters. We did not observe any clear elevation pattern in microbial biomass, and microbial activity revealed contrasting elevational patterns between transects. We found relatively large horizontal variability in MCS (i.e., between sites of corresponding elevation in different transects), mainly due to differences in the composition of bacterial PLFAs, but also a systematic altitudinal shift in MCS related to different habitat preferences of fungi and bacteria, which resulted in high fungi-to-bacteria ratios at the most elevated sites. The biological soil crusts on these most elevated, unvegetated sites can host microbial assemblages of a size and activity comparable to those of the arctic tundra ecosystem. The key environmental factors determining horizontal and vertical changes in soil microbial properties were soil pH, organic carbon content, soil moisture and Mg2+ availability.

  20. In-Drift Microbial Communities

    Energy Technology Data Exchange (ETDEWEB)

    D. Jolley

    2000-11-09

    As directed by written work direction (CRWMS M and O 1999f), Performance Assessment (PA) developed a model for microbial communities in the engineered barrier system (EBS) as documented here. The purpose of this model is to assist Performance Assessment and its Engineered Barrier Performance Section in modeling the geochemical environment within a potential repository drift for TSPA-SR/LA, thus allowing PA to provide a more detailed and complete near-field geochemical model and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near Field Environment (NFE) Revision 2 (NRC 1999). This model and its predecessor (the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document, CRWMS M and O 1998a) was developed to respond to the applicable KTIs. Additionally, because of the previous development of the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a), the M and O was effectively able to resolve a previous KTI concern regarding the effects of microbial processes on seepage and flow (NRC 1998). This document supercedes the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a). This document provides the conceptual framework of the revised in-drift microbial communities model to be used in subsequent performance assessment (PA) analyses.

  1. In-Drift Microbial Communities

    International Nuclear Information System (INIS)

    Jolley, D.

    2000-01-01

    As directed by written work direction (CRWMS M and O 1999f), Performance Assessment (PA) developed a model for microbial communities in the engineered barrier system (EBS) as documented here. The purpose of this model is to assist Performance Assessment and its Engineered Barrier Performance Section in modeling the geochemical environment within a potential repository drift for TSPA-SR/LA, thus allowing PA to provide a more detailed and complete near-field geochemical model and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near Field Environment (NFE) Revision 2 (NRC 1999). This model and its predecessor (the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document, CRWMS M and O 1998a) was developed to respond to the applicable KTIs. Additionally, because of the previous development of the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a), the M and O was effectively able to resolve a previous KTI concern regarding the effects of microbial processes on seepage and flow (NRC 1998). This document supercedes the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a). This document provides the conceptual framework of the revised in-drift microbial communities model to be used in subsequent performance assessment (PA) analyses

  2. Assessing habitat selection when availability changes

    Science.gov (United States)

    Arthur, S.; Garner, G.; ,

    1996-01-01

    We present a method of comparing data on habitat use and availability that allows availability to differ among observations. This method is applicable when habitats change over time and when animals are unable to move throughout a predetermined study area between observations. We used maximum-likelihood techniques to derive an index that estimates the probability that each habitat type would be used if all were equally available. We also demonstrate how these indices can be used to compare relative use of available habitats, assign them ranks, and assess statistical differences between pairs of indices. The set of these indices for all habitats can be compared between groups of animals that represent different seasons, sex or age classes, or experimental treatments. This method allows quantitative comparisons among types and is not affected by arbitrary decisions about which habitats to include in the study. We provide an example by comparing the availability of four categories of sea ice concentration to their use by adult female polar bears, whose movements were monitored by satellite radio tracking in the Bering and Chukchi Seas during 1990. Use of ice categories by bears was nonrandom, and the pattern of use differed between spring and late summer seasons.

  3. Salmon River Habitat Enhancement, 1989 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, Mike

    1989-04-01

    This project was funded by the Bonneville Power Administration (BPA). The annual report contains three individual subproject papers detailing tribal fisheries work completed during the summer and fall of 1989. Subproject 1 contains summaries of evaluation/monitoring efforts associated with the Bear Valley Creek, Idaho enhancement project. Subproject 2 contains an evaluation of the Yankee Fork of the Salmon River habitat enhancement project. This report has been sub-divided into two parts: Part 1; stream evaluation and Part 2; pond series evaluation. Subproject 3 concerns the East Fork of the Salmon River, Idaho. This report summarizes the evaluation of the project to date including the 1989 pre-construction evaluation conducted within the East Fork drainage. Dredge mining has degraded spawning and rearing habitat for chinook salmon and steelhead trout in the Yankee Fork drainage of the Salmon River and in Bear Valley Creek. Mining, agricultural, and grazing practices degraded habitat in the East Fork of the Salmon River. Biological monitoring of the success of habitat enhancement for Bear Valley Creek and Yankee Fork are presented in this report. Physical and biological inventories prior to habitat enhancement in East Fork were also conducted. Four series of off-channel ponds of the Yankee Fork are shown to provide effective rearing habitat for chinook salmon. 45 refs., 49 figs., 24 tabs.

  4. Transient diabetes insipidus in pregnancy

    Science.gov (United States)

    Gunawardana, Kavinga; Grossman, Ashley

    2015-01-01

    Summary Gestational diabetes insipidus (DI) is a rare complication of pregnancy, usually developing in the third trimester and remitting spontaneously 4–6 weeks post-partum. It is mainly caused by excessive vasopressinase activity, an enzyme expressed by placental trophoblasts which metabolises arginine vasopressin (AVP). Its diagnosis is challenging, and the treatment requires desmopressin. A 38-year-old Chinese woman was referred in the 37th week of her first single-gestation due to polyuria, nocturia and polydipsia. She was known to have gestational diabetes mellitus diagnosed in the second trimester, well-controlled with diet. Her medical history was unremarkable. Physical examination demonstrated decreased skin turgor; her blood pressure was 102/63 mmHg, heart rate 78 beats/min and weight 53 kg (BMI 22.6 kg/m2). Laboratory data revealed low urine osmolality 89 mOsmol/kg (350–1000), serum osmolality 293 mOsmol/kg (278–295), serum sodium 144 mmol/l (135–145), potassium 4.1 mmol/l (3.5–5.0), urea 2.2 mmol/l (2.5–6.7), glucose 3.5 mmol/l and HbA1c 5.3%. Bilirubin, alanine transaminase, alkaline phosphatase and full blood count were normal. The patient was started on desmopressin with improvement in her symptoms, and normalisation of serum and urine osmolality (280 and 310 mOsmol/kg respectively). A fetus was delivered at the 39th week without major problems. After delivery, desmopressin was stopped and she had no further evidence of polyuria, polydipsia or nocturia. Her sodium, serum/urine osmolality at 12-weeks post-partum were normal. A pituitary magnetic resonance imaging (MRI) revealed the neurohypophyseal T1-bright spot situated ectopically, with a normal adenohypophysis and infundibulum. She remains clinically well, currently breastfeeding, and off all medication. This case illustrates some challenges in the diagnosis and management of transient gestational DI. Learning points Gestational DI is a rare complication of

  5. Transient diabetes insipidus in pregnancy.

    Science.gov (United States)

    Marques, Pedro; Gunawardana, Kavinga; Grossman, Ashley

    2015-01-01

    Gestational diabetes insipidus (DI) is a rare complication of pregnancy, usually developing in the third trimester and remitting spontaneously 4-6 weeks post-partum. It is mainly caused by excessive vasopressinase activity, an enzyme expressed by placental trophoblasts which metabolises arginine vasopressin (AVP). Its diagnosis is challenging, and the treatment requires desmopressin. A 38-year-old Chinese woman was referred in the 37th week of her first single-gestation due to polyuria, nocturia and polydipsia. She was known to have gestational diabetes mellitus diagnosed in the second trimester, well-controlled with diet. Her medical history was unremarkable. Physical examination demonstrated decreased skin turgor; her blood pressure was 102/63 mmHg, heart rate 78 beats/min and weight 53 kg (BMI 22.6 kg/m(2)). Laboratory data revealed low urine osmolality 89 mOsmol/kg (350-1000), serum osmolality 293 mOsmol/kg (278-295), serum sodium 144 mmol/l (135-145), potassium 4.1 mmol/l (3.5-5.0), urea 2.2 mmol/l (2.5-6.7), glucose 3.5 mmol/l and HbA1c 5.3%. Bilirubin, alanine transaminase, alkaline phosphatase and full blood count were normal. The patient was started on desmopressin with improvement in her symptoms, and normalisation of serum and urine osmolality (280 and 310 mOsmol/kg respectively). A fetus was delivered at the 39th week without major problems. After delivery, desmopressin was stopped and she had no further evidence of polyuria, polydipsia or nocturia. Her sodium, serum/urine osmolality at 12-weeks post-partum were normal. A pituitary magnetic resonance imaging (MRI) revealed the neurohypophyseal T1-bright spot situated ectopically, with a normal adenohypophysis and infundibulum. She remains clinically well, currently breastfeeding, and off all medication. This case illustrates some challenges in the diagnosis and management of transient gestational DI. Gestational DI is a rare complication of pregnancy occurring in two to four out of

  6. Drift in ocean currents impacts intergenerational microbial exposure to temperature.

    Science.gov (United States)

    Doblin, Martina A; van Sebille, Erik

    2016-05-17

    Microbes are the foundation of marine ecosystems [Falkowski PG, Fenchel T, Delong EF (2008) Science 320(5879):1034-1039]. Until now, the analytical framework for understanding the implications of ocean warming on microbes has not considered thermal exposure during transport in dynamic seascapes, implying that our current view of change for these critical organisms may be inaccurate. Here we show that upper-ocean microbes experience along-trajectory temperature variability up to 10 °C greater than seasonal fluctuations estimated in a static frame, and that this variability depends strongly on location. These findings demonstrate that drift in ocean currents can increase the thermal exposure of microbes and suggests that microbial populations with broad thermal tolerance will survive transport to distant regions of the ocean and invade new habitats. Our findings also suggest that advection has the capacity to influence microbial community assemblies, such that regions with strong currents and large thermal fluctuations select for communities with greatest plasticity and evolvability, and communities with narrow thermal performance are found where ocean currents are weak or along-trajectory temperature variation is low. Given that fluctuating environments select for individual plasticity in microbial lineages, and that physiological plasticity of ancestors can predict the magnitude of evolutionary responses of subsequent generations to environmental change [Schaum CE, Collins S (2014) Proc Biol Soc 281(1793):20141486], our findings suggest that microbial populations in the sub-Antarctic (∼40°S), North Pacific, and North Atlantic will have the most capacity to adapt to contemporary ocean warming.

  7. Who's coming to dinner? Microbial phylogenetic analyses of various subsurface petroleum well environments for MEOR applications

    Energy Technology Data Exchange (ETDEWEB)

    Keeler, Sharon J.; Fallon, Robert; Jackson, Scott; Zhang, Shiping; Tomb, Jean-Francois; Miller, Mark A.; Rees, Bethany [Central Research and Development (Canada)

    2011-07-01

    This paper discussed the microbial phylogenetic analyses of various subsurface petroleum well environments for microbial-enhanced oil recovery (MEOR) applications. The objective is to add nutrients and microbes to injection water. Close to 47,000 compounds are present in petroleum and most of them are polyaromatic hydrocarbons (PAHs). Microbes that can predominate the biomass produced and the over all bioactivity are needed. Changing the electron acceptor modifies the microbial community. Characterization of microbial diversity in production water with two independent molecular methods is shown. The geology of well systems in North America was analyzed; the analyses and the results are given. Summarizing the North Slope reservoir system phylogenetics, it can be said that many genera found in association with other petroleum environments suggest they are autocthonous and transiently very high levels of acetate signify a mutual metabolic codependency on the amount of acetate present in the system.

  8. Microbial production of biovanillin

    Directory of Open Access Journals (Sweden)

    A. Converti

    2010-10-01

    Full Text Available This review aims at providing an overview on the microbial production of vanillin, a new alternative method for the production of this important flavor of the food industry, which has the potential to become economically competitive in the next future. After a brief description of the applications of vanillin in different industrial sectors and of its physicochemical properties, we described the traditional ways of providing vanillin, specifically extraction and chemical synthesis (mainly oxidation and compared them with the new biotechnological options, i.e., biotransformations of caffeic acid, veratraldehyde and mainly ferulic acid. In the second part of the review, emphasis has been addressed to the factors most influencing the bioproduction of vanillin, specifically the age of inoculum, pH, temperature, type of co-substrate, as well as the inhibitory effects exerted either by excess substrate or product. The final part of the work summarized the downstream processes and the related unit operations involved in the recovery of vanillin from the bioconversion medium.

  9. Microbial production of biovanillin.

    Science.gov (United States)

    Converti, A; Aliakbarian, B; Domínguez, J M; Bustos Vázquez, G; Perego, P

    2010-07-01

    This review aims at providing an overview on the microbial production of vanillin, a new alternative method for the production of this important flavor of the food industry, which has the potential to become economically competitive in the next future. After a brief description of the applications of vanillin in different industrial sectors and of its physicochemical properties, we described the traditional ways of providing vanillin, specifically extraction and chemical synthesis (mainly oxidation) and compared them with the new biotechnological options, i.e., biotransformations of caffeic acid, veratraldehyde and mainly ferulic acid. In the second part of the review, emphasis has been addressed to the factors most influencing the bioproduction of vanillin, specifically the age of inoculum, pH, temperature, type of co-substrate, as well as the inhibitory effects exerted either by excess substrate or product. The final part of the work summarized the downstream processes and the related unit operations involved in the recovery of vanillin from the bioconversion medium.

  10. Microbial Propionic Acid Production

    Directory of Open Access Journals (Sweden)

    R. Axayacatl Gonzalez-Garcia

    2017-05-01

    Full Text Available Propionic acid (propionate is a commercially valuable carboxylic acid produced through microbial fermentation. Propionic acid is mainly used in the food industry but has recently found applications in the cosmetic, plastics and pharmaceutical industries. Propionate can be produced via various metabolic pathways, which can be classified into three major groups: fermentative pathways, biosynthetic pathways, and amino acid catabolic pathways. The current review provides an in-depth description of the major metabolic routes for propionate production from an energy optimization perspective. Biological propionate production is limited by high downstream purification costs which can be addressed if the target yield, productivity and titre can be achieved. Genome shuffling combined with high throughput omics and metabolic engineering is providing new opportunities, and biological propionate production is likely to enter the market in the not so distant future. In order to realise the full potential of metabolic engineering and heterologous expression, however, a greater understanding of metabolic capabilities of the native producers, the fittest producers, is required.

  11. Four RNA families with functional transient structures.

    Science.gov (United States)

    Zhu, Jing Yun A; Meyer, Irmtraud M

    2015-01-01

    Protein-coding and non-coding RNA transcripts perform a wide variety of cellular functions in diverse organisms. Several of their functional roles are expressed and modulated via RNA structure. A given transcript, however, can have more than a single functional RNA structure throughout its life, a fact which has been previously overlooked. Transient RNA structures, for example, are only present during specific time intervals and cellular conditions. We here introduce four RNA families with transient RNA structures that play distinct and diverse functional roles. Moreover, we show that these transient RNA structures are structurally well-defined and evolutionarily conserved. Since Rfam annotates one structure for each family, there is either no annotation for these transient structures or no such family. Thus, our alignments either significantly update and extend the existing Rfam families or introduce a new RNA family to Rfam. For each of the four RNA families, we compile a multiple-sequence alignment based on experimentally verified transient and dominant (dominant in terms of either the thermodynamic stability and/or attention received so far) RNA secondary structures using a combination of automated search via covariance model and manual curation. The first alignment is the Trp operon leader which regulates the operon transcription in response to tryptophan abundance through alternative structures. The second alignment is the HDV ribozyme which we extend to the 5' flanking sequence. This flanking sequence is involved in the regulation of the transcript's self-cleavage activity. The third alignment is the 5' UTR of the maturation protein from Levivirus which contains a transient structure that temporarily postpones the formation of the final inhibitory structure to allow translation of maturation protein. The fourth and last alignment is the SAM riboswitch which regulates the downstream gene expression by assuming alternative structures upon binding of SAM. All

  12. Transient cognitive dynamics, metastability, and decision making.

    Directory of Open Access Journals (Sweden)

    Mikhail I Rabinovich

    2008-05-01

    Full Text Available The idea that cognitive activity can be understood using nonlinear dynamics has been intensively discussed at length for the last 15 years. One of the popular points of view is that metastable states play a key role in the execution of cognitive functions. Experimental and modeling studies suggest that most of these functions are the result of transient activity of large-scale brain networks in the presence of noise. Such transients may consist of a sequential switching between different metastable cognitive states. The main problem faced when using dynamical theory to describe transient cognitive processes is the fundamental contradiction between reproducibility and flexibility of transient behavior. In this paper, we propose a theoretical description of transient cognitive dynamics based on the interaction of functionally dependent metastable cognitive states. The mathematical image of such transient activity is a stable heteroclinic channel, i.e., a set of trajectories in the vicinity of a heteroclinic skeleton that consists of saddles and unstable separatrices that connect their surroundings. We suggest a basic mathematical model, a strongly dissipative dynamical system, and formulate the conditions for the robustness and reproducibility of cognitive transients that satisfy the competing requirements for stability and flexibility. Based on this approach, we describe here an effective solution for the problem of sequential decision making, represented as a fixed time game: a player takes sequential actions in a changing noisy environment so as to maximize a cumulative reward. As we predict and verify in computer simulations, noise plays an important role in optimizing the gain.

  13. Advanced Instrumentation for Transient Reactor Testing

    Energy Technology Data Exchange (ETDEWEB)

    Corradini, Michael L.; Anderson, Mark; Imel, George; Blue, Tom; Roberts, Jeremy; Davis, Kurt

    2018-01-31

    Transient testing involves placing fuel or material into the core of specialized materials test reactors that are capable of simulating a range of design basis accidents, including reactivity insertion accidents, that require the reactor produce short bursts of intense highpower neutron flux and gamma radiation. Testing fuel behavior in a prototypic neutron environment under high-power, accident-simulation conditions is a key step in licensing nuclear fuels for use in existing and future nuclear power plants. Transient testing of nuclear fuels is needed to develop and prove the safety basis for advanced reactors and fuels. In addition, modern fuel development and design increasingly relies on modeling and simulation efforts that must be informed and validated using specially designed material performance separate effects studies. These studies will require experimental facilities that are able to support variable scale, highly instrumented tests providing data that have appropriate spatial and temporal resolution. Finally, there are efforts now underway to develop advanced light water reactor (LWR) fuels with enhanced performance and accident tolerance. These advanced reactor designs will also require new fuel types. These new fuels need to be tested in a controlled environment in order to learn how they respond to accident conditions. For these applications, transient reactor testing is needed to help design fuels with improved performance. In order to maximize the value of transient testing, there is a need for in-situ transient realtime imaging technology (e.g., the neutron detection and imaging system like the hodoscope) to see fuel motion during rapid transient excursions with a higher degree of spatial and temporal resolution and accuracy. There also exists a need for new small, compact local sensors and instrumentation that are capable of collecting data during transients (e.g., local displacements, temperatures, thermal conductivity, neutron flux, etc.).

  14. Microbial DNA fingerprinting of human fingerprints: dynamic colonization of fingertip microflora challenges human host inferences for forensic purposes.

    Science.gov (United States)

    Tims, Sebastian; van Wamel, Willem; Endtz, Hubert P; van Belkum, Alex; Kayser, Manfred

    2010-09-01

    Human fingertip microflora is transferred to touched objects and may provide forensically relevant information on individual hosts, such as on geographic origins, if endogenous microbial skin species/strains would be retrievable from physical fingerprints and would carry geographically restricted DNA diversity. We tested the suitability of physical fingerprints for revealing human host information, with geographic inference as example, via microbial DNA fingerprinting. We showed that the transient exogenous fingertip microflora is frequently different from the resident endogenous bacteria of the same individuals. In only 54% of the experiments, the DNA analysis of the transient fingertip microflora allowed the detection of defined, but often not the major, elements of the resident microflora. Although we found microbial persistency in certain individuals, time-wise variation of transient and resident microflora within individuals was also observed when resampling fingerprints after 3 weeks. While microbial species differed considerably in their frequency spectrum between fingerprint samples from volunteers in Europe and southern Asia, there was no clear geographic distinction between Staphylococcus strains in a cluster analysis, although bacterial genotypes did not overlap between both continental regions. Our results, though limited in quantity, clearly demonstrate that the dynamic fingerprint microflora challenges human host inferences for forensic purposes including geographic ones. Overall, our results suggest that human fingerprint microflora is too dynamic to allow for forensic marker developments for retrieving human information.

  15. Anthropogenic areas as incidental substitutes for original habitat.

    Science.gov (United States)

    Martínez-Abraín, Alejandro; Jiménez, Juan

    2016-06-01

    One speaks of ecological substitutes when an introduced species performs, to some extent, the ecosystem function of an extirpated native species. We suggest that a similar case exists for habitats. Species evolve within ecosystems, but habitats can be destroyed or modified by natural and human-made causes. Sometimes habitat alteration forces animals to move to or remain in a suboptimal habitat type. In that case, the habitat is considered a refuge, and the species is called a refugee. Typically refugee species have lower population growth rates than in their original habitats. Human action may lead to the unintended generation of artificial or semiartificial habitat types that functionally resemble the essential features of the original habitat and thus allow a population growth rate of the same magnitude or higher than in the original habitat. We call such areas substitution habitats and define them as human-made habitats within the focal species range that by chance are partial substitutes for the species' original habitat. We call species occupying a substitution habitat adopted species. These are 2 new terms in conservation biology. Examples of substitution habitats are dams for European otters, wheat and rice fields for many steppeland and aquatic birds, and urban areas for storks, falcons, and swifts. Although substitution habitats can bring about increased resilience against the agents of global change, the conservation of original habitat types remains a conservation priority. © 2016 Society for Conservation Biology.

  16. Habitat connectivity and fragmented nuthatch populations in agricultural landscapes

    NARCIS (Netherlands)

    Langevelde, van F.

    1999-01-01

    In agricultural landscapes, the habitat of many species is subject to fragmentation. When the habitat of a species is fragmented and the distances between patches of habitat are large relative to the movement distances of the species, it can be expected that the degree of habitat

  17. Development of a Regional Habitat Classification Scheme for the ...

    African Journals Online (AJOL)

    development, image processing techniques and field survey methods are outlined. Habitat classification, and regional-scale comparisons of relative habitat composition are described. The study demonstrates the use of remote sensing data to construct digital habitat maps for the comparison of regional habitat coverage, ...

  18. [Characterization and microbial community shifts of rice strawdegrading microbial consortia].

    Science.gov (United States)

    Wang, Chunfang; Ma, Shichun; Huang, Yan; Liu, Laiyan; Fan, Hui; Deng, Yu

    2016-12-04

    To study the relationship between microbial community and degradation rate of rice straw, we compared and analyzed cellulose-decomposing ability, microbial community structures and shifts of microbial consortia F1 and F2. We determined exoglucanase activity by 3, 5-dinitrosalicylic acid colorimetry. We determined content of cellulose, hemicellulose and lignin in rice straw by Van Soest method, and calculated degradation rates of rice straw by the weight changes before and after a 10-day incubation. We analyzed and compared the microbial communities and functional microbiology shifts by clone libraries, Miseq analysis and real time-PCR based on the 16S rRNA gene and cel48 genes. Total degradation rate, cellulose, and hemicellulose degradation rate of microbial consortia F1 were significantly higher than that of F2. The variation trend of exoglucanase activity in both microbial consortia F1 and F2 was consistent with that of cel48 gene copies. Microbial diversity of F1 was complex with aerobic bacteria as dominant species, whereas that of F2 was simple with a high proportion of anaerobic cellulose decomposing bacteria in the later stage of incubation. In the first 4 days, unclassified Bacillales and Bacillus were dominant in both F1 and F2. The dominant species and abundance became different after 4-day incubation, Bacteroidetes and Firmicutes were dominant phyla of F1 and F2, respectively. Although Petrimonas and Pusillimonas were common dominant species in F1 and F2, abundance of Petrimonas in F2 (38.30%) was significantly higher than that in F1 (9.47%), and the abundance of Clostridiales OPB54 in F2 increased to 14.85% after 8-day incubation. The abundance of cel48 gene related with cellulose degradation rate and exoglucanase activity, and cel48 gene has the potential as a molecular marker to monitor the process of cellulose degradation. Microbial community structure has a remarkable impact on the degradation efficiency of straw cellulose, and Petrimonas

  19. CADDIS Volume 2. Sources, Stressors and Responses: Physical Habitat - Detailed Conceptual Diagram

    Science.gov (United States)

    Introduction to the Physical Habitat module, when to list Physical Habitat as a candidate cause, ways to measure Physical Habitat, simple and detailed conceptual diagrams for Physical Habitat, Physical Habitat module references and literature reviews.

  20. CADDIS Volume 2. Sources, Stressors and Responses: Physical Habitat - Simple Conceptual Diagram

    Science.gov (United States)

    Introduction to the Physical Habitat module, when to list Physical Habitat as a candidate cause, ways to measure Physical Habitat, simple and detailed conceptual diagrams for Physical Habitat, Physical Habitat module references and literature reviews.

  1. Long-term habitat changes in a protected area: Implications for herpetofauna habitat management and restoration.

    Science.gov (United States)

    Markle, Chantel E; Chow-Fraser, Gillian; Chow-Fraser, Patricia

    2018-01-01

    Point Pelee National Park, located at the southern-most tip of Canada's mainland, historically supported a large number of herpetofauna species; however, despite nearly a century of protection, six snake and five amphibian species have disappeared, and remaining species-at-risk populations are thought to be in decline. We hypothesized that long-term changes in availability and distribution of critical habitat types may have contributed to the disappearance of herpetofauna. To track habitat changes we used aerial image data spanning 85 years (1931-2015) and manually digitized and classified image data using a standardized framework. Change-detection analyses were used to evaluate the relative importance of proportionate loss and fragmentation of 17 habitat types. Marsh habitat diversity and aquatic connectivity has declined since 1931. The marsh matrix transitioned from a graminoid and forb shallow marsh interspersed with water to a cattail dominated marsh, altering critical breeding, foraging, and overwintering habitat. Reduced diversity of marsh habitats appears to be linked to the expansion of invasive Phragmites australis, which invaded prior to 2000. Loss of open habitats such as savanna and meadow has reduced availability of high quality thermoregulation habitat for reptiles. Restoration of the northwestern region and tip of Point Pelee National Park to a mixed landscape of shallow wetlands (cattail, graminoid, forb, open water) and eradication of dense Phragmites stands should improve habitat diversity. Our results suggest that long-term landscape changes resulting from habitat succession and invasive species can negatively affect habitat suitability for herpetofauna and protection of land alone does not necessarily equate to protection of sensitive herpetofauna.

  2. Long-term habitat changes in a protected area: Implications for herpetofauna habitat management and restoration.

    Directory of Open Access Journals (Sweden)

    Chantel E Markle

    Full Text Available Point Pelee National Park, located at the southern-most tip of Canada's mainland, historically supported a large number of herpetofauna species; however, despite nearly a century of protection, six snake and five amphibian species have disappeared, and remaining species-at-risk populations are thought to be in decline. We hypothesized that long-term changes in availability and distribution of critical habitat types may have contributed to the disappearance of herpetofauna. To track habitat changes we used aerial image data spanning 85 years (1931-2015 and manually digitized and classified image data using a standardized framework. Change-detection analyses were used to evaluate the relative importance of proportionate loss and fragmentation of 17 habitat types. Marsh habitat diversity and aquatic connectivity has declined since 1931. The marsh matrix transitioned from a graminoid and forb shallow marsh interspersed with water to a cattail dominated marsh, altering critical breeding, foraging, and overwintering habitat. Reduced diversity of marsh habitats appears to be linked to the expansion of invasive Phragmites australis, which invaded prior to 2000. Loss of open habitats such as savanna and meadow has reduced availability of high quality thermoregulation habitat for reptiles. Restoration of the northwestern region and tip of Point Pelee National Park to a mixed landscape of shallow wetlands (cattail, graminoid, forb, open water and eradication of dense Phragmites stands should improve habitat diversity. Our results suggest that long-term landscape changes resulting from habitat succession and invasive species can negatively affect habitat suitability for herpetofauna and protection of land alone does not necessarily equate to protection of sensitive herpetofauna.

  3. Soil microbial succession along a chronosequence on a High Arctic glacier foreland, Ny-Ålesund, Svalbard: 10 years' change

    Science.gov (United States)

    Yoshitake, Shinpei; Uchida, Masaki; Iimura, Yasuo; Ohtsuka, Toshiyuki; Nakatsubo, Takayuki

    2018-06-01

    Rapid glacial retreat in the High Arctic causes the expansion of new habitats, but the successional trajectories of soil microbial communities are not fully understood. We examined microbial succession along a chronosequence twice with a 10-year interval in a High Arctic glacier foreland. Soil samples were collected from five study sites with different ages and phospholipid fatty acids analysis was conducted to investigate the microbial biomass and community structure. Microbial biomass did not differ significantly between the two sampling times but tended to increase with the chronosequence and showed a significant correlation with soil carbon (C) and nitrogen (N) content. Microbial community structure clearly differed along the chronosequence and was correlated with C and N content. The largest shift in community structure over 10 years was observed in the newly exposed sites after deglaciation. The accumulation of soil organic matter was regarded as an important determinant both of microbial biomass and community structure over the successional period. In contrast, the initial microbial community on the newly exposed soil changed rapidly even in the High Arctic, suggesting that some key soil processes such as C and N cycling can also shift within the relatively short period after rapid glacial retreat.

  4. Microbial ecology of extreme environments: Antarctic yeasts and growth in substrate-limited habitats

    Science.gov (United States)

    Vishniac, H. S.

    1985-01-01

    The high, dry valleys of the Ross Desert of Antarctic, characterized by extremely low temperatures, aridity and a depauperate biota, are used as an analog of the postulated extreme climates of other planetary bodies of the Solar System to test the hypothesis that if life could be supported by Ross, it might be possible where similar conditions prevail. The previously considered sterility of the Ross Desert soil ecosystem has yielded up an indigenous yeast, Cryptoccus vishniacci, which is able to resist the extremes of cold, wet and dry freezing, and long arid periods, while making minimal nutritional demands on the soil.

  5. The effects of earthworms .i.Eisenia./i. spp. on microbial community are habitat dependent

    Czech Academy of Sciences Publication Activity Database

    Koubová, Anna; Chroňáková, Alica; Pižl, Václav; Sánchez-Monedero, M.A.; Elhottová, Dana

    2015-01-01

    Roč. 68, May-June (2015), s. 42-55 ISSN 1164-5563 R&D Projects: GA AV ČR IAA600200704; GA MŠk LC06066 Institutional support: RVO:60077344 Keywords : earthworms * soil * compost * vermiculture * archaea * bacteria Subject RIV: EH - Ecology, Behaviour Impact factor: 1.951, year: 2015

  6. Biodegradation of engine oil by fungi from mangrove habitat.

    Science.gov (United States)

    Ameen, Fuad; Hadi, Sarfaraz; Moslem, Mohamed; Al-Sabri, Ahmed; Yassin, Mohamed A

    2015-01-01

    The pollution of land and water by petroleum compounds is a matter of growing concern necessitating the development of methodologies, including microbial biodegradation, to minimize the impending impacts. It has been extensively reported that fungi from polluted habitats have the potential to degrade pollutants, including petroleum compounds. The Red Sea is used extensively for the transport of oil and is substantially polluted, due to leaks, spills, and occasional accidents. Tidal water, floating debris, and soil sediment were collected from mangrove stands on three polluted sites along the Red Sea coast of Saudi Arabia and forty-five fungal isolates belonging to 13 genera were recovered from these samples. The isolates were identified on the basis of a sequence analysis of the 18S rRNA gene fragment. Nine of these isolates were found to be able to grow in association with engine oil, as the sole carbon source, under in vitro conditions. These selected isolates and their consortium accumulated greater biomass, liberated more CO2, and produced higher levels of extracellular enzymes, during cultivation with engine oil as compared with the controls. These observations were authenticated by gas chromatography-mass spectrophotometry (GC-MS) analysis, which indicated that many high mass compounds present in the oil before treatment either disappeared or showed diminished levels.

  7. Switching transients in a superconducting coil

    International Nuclear Information System (INIS)

    Owen, E.W.; Shimer, D.W.

    1983-01-01

    A study is made of the transients caused by the fast dump of large superconducting coils. Theoretical analysis, computer simulation, and actual measurements are used. Theoretical analysis can only be applied to the simplest of models. In the computer simulations two models are used, one in which the coil is divided into ten segments and another in which a single coil is employed. The circuit breaker that interrupts the current to the power supply, causing a fast dump, is represented by a time and current dependent conductance. Actual measurements are limited to measurements made incidental to performance tests on the MFTF Yin-yang coils. It is found that the breaker opening time is the critical factor in determining the size and shape of the transient. Instantaneous opening of the breaker causes a lightly damped transient with large amplitude voltages to ground. Increasing the opening time causes the transient to become a monopulse of decreasing amplitude. The voltages at the external terminals are determined by the parameters of the external circuit. For fast opening times the frequency depends on the dump resistor inductance, the circuit capacitance, and the amplitude on the coil current. For slower openings the dump resistor inductance and the current determine the amplitude of the voltage to ground at the terminals. Voltages to ground are less in the interior of the coil, where transients related to the parameters of the coil itself are observed

  8. SPIRITS: Uncovering Unusual Infrared Transients with Spitzer

    International Nuclear Information System (INIS)

    Kasliwal, Mansi M.; Jencson, Jacob E.; Tinyanont, Samaporn; Cao, Yi; Cook, David; Bally, John; Masci, Frank; Armus, Lee; Cody, Ann Marie; Bond, Howard E.; Contreras, Carlos; Dykhoff, Devin A.; Amodeo, Samuel; Carlon, Robert L.; Cass, Alexander C.; Corgan, David T.; Faella, Joseph; Boyer, Martha; Cantiello, Matteo; Fox, Ori D.

    2017-01-01

    We present an ongoing, five-year systematic search for extragalactic infrared transients, dubbed SPIRITS—SPitzer InfraRed Intensive Transients Survey. In the first year, using Spitzer /IRAC, we searched 190 nearby galaxies with cadence baselines of one month and six months. We discovered over 1958 variables and 43 transients. Here, we describe the survey design and highlight 14 unusual infrared transients with no optical counterparts to deep limits, which we refer to as SPRITEs (eSPecially Red Intermediate-luminosity Transient Events). SPRITEs are in the infrared luminosity gap between novae and supernovae, with [4.5] absolute magnitudes between −11 and −14 (Vega-mag) and [3.6]–[4.5] colors between 0.3 mag and 1.6 mag. The photometric evolution of SPRITEs is diverse, ranging from <0.1 mag yr −1 to >7 mag yr −1 . SPRITEs occur in star-forming galaxies. We present an in-depth study of one of them, SPIRITS 14ajc in Messier 83, which shows shock-excited molecular hydrogen emission. This shock may have been triggered by the dynamic decay of a non-hierarchical system of massive stars that led to either the formation of a binary or a protostellar merger.

  9. SPIRITS: Uncovering Unusual Infrared Transients with Spitzer

    Energy Technology Data Exchange (ETDEWEB)

    Kasliwal, Mansi M.; Jencson, Jacob E.; Tinyanont, Samaporn; Cao, Yi; Cook, David [Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Bally, John [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309 (United States); Masci, Frank; Armus, Lee [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Cody, Ann Marie [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Bond, Howard E. [Dept. of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Contreras, Carlos [Las Campanas Observatory, Carnegie Observatories, Casilla 601, La Serena (Chile); Dykhoff, Devin A.; Amodeo, Samuel; Carlon, Robert L.; Cass, Alexander C.; Corgan, David T.; Faella, Joseph [Minnesota Institute for Astrophysics, School of Physics and Astronomy, 116 Church Street, S. E., University of Minnesota, Minneapolis, MN 55455 (United States); Boyer, Martha [NASA Goddard Space Flight Center, MC 665, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Cantiello, Matteo [Center for Computational Astrophysics, Flatiron Institute, 162 Fifth Avenue, New York, NY 10010 (United States); Fox, Ori D. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); and others

    2017-04-20

    We present an ongoing, five-year systematic search for extragalactic infrared transients, dubbed SPIRITS—SPitzer InfraRed Intensive Transients Survey. In the first year, using Spitzer /IRAC, we searched 190 nearby galaxies with cadence baselines of one month and six months. We discovered over 1958 variables and 43 transients. Here, we describe the survey design and highlight 14 unusual infrared transients with no optical counterparts to deep limits, which we refer to as SPRITEs (eSPecially Red Intermediate-luminosity Transient Events). SPRITEs are in the infrared luminosity gap between novae and supernovae, with [4.5] absolute magnitudes between −11 and −14 (Vega-mag) and [3.6]–[4.5] colors between 0.3 mag and 1.6 mag. The photometric evolution of SPRITEs is diverse, ranging from <0.1 mag yr{sup −1} to >7 mag yr{sup −1}. SPRITEs occur in star-forming galaxies. We present an in-depth study of one of them, SPIRITS 14ajc in Messier 83, which shows shock-excited molecular hydrogen emission. This shock may have been triggered by the dynamic decay of a non-hierarchical system of massive stars that led to either the formation of a binary or a protostellar merger.

  10. Transient particle emission measurement with optical techniques

    Science.gov (United States)

    Bermúdez, Vicente; Luján, José M.; Serrano, José R.; Pla, Benjamín

    2008-06-01

    Particulate matter is responsible for some respiratory and cardiovascular diseases. In addition, it is one of the most important pollutants of high-speed direct injection (HSDI) passenger car engines. Current legislation requires particulate dilution tunnels for particulate matter measuring. However for development work, dilution tunnels are expensive and sometimes not useful since they are not able to quantify real-time particulate emissions during transient operation. In this study, the use of a continuous measurement opacimeter and a fast response HFID is proven to be a good alternative to obtain instantaneous particle mass emissions during transient operation (due to particulate matter consisting mainly of soot and SOF). Some methods and correlations available from literature, but developed for steady conditions, are evaluated during transient operation by comparing with mini-tunnel measurements during the entire MVEG-A transient cycle. A new correlation was also derived from this evaluation. Results for soot and SOF (obtained from the new correlation proposed) are compared with soot and SOF captured with particulate filters, which have been separated by means of an SOF extraction method. Finally, as an example of ECU design strategies using these sort of correlations, the EGR valve opening is optimized during transient operation. The optimization is performed while simultaneously taking into account instantaneous fuel consumption, particulate emissions (calculated with the proposed correlation) and other regulated engine pollutants.

  11. Biotechnological Aspects of Microbial Extracellular Electron Transfer

    Science.gov (United States)

    Kato, Souichiro

    2015-01-01

    Extracellular electron transfer (EET) is a type of microbial respiration that enables electron transfer between microbial cells and extracellular solid materials, including naturally-occurring metal compounds and artificial electrodes. Microorganisms harboring EET abilities have received considerable attention for their various biotechnological applications, in addition to their contribution to global energy and material cycles. In this review, current knowledge on microbial EET and its application to diverse biotechnologies, including the bioremediation of toxic metals, recovery of useful metals, biocorrosion, and microbial electrochemical systems (microbial fuel cells and microbial electrosynthesis), were introduced. Two potential biotechnologies based on microbial EET, namely the electrochemical control of microbial metabolism and electrochemical stimulation of microbial symbiotic reactions (electric syntrophy), were also discussed. PMID:26004795

  12. Hydrodynamics of microbial filter feeding.

    Science.gov (United States)

    Nielsen, Lasse Tor; Asadzadeh, Seyed Saeed; Dölger, Julia; Walther, Jens H; Kiørboe, Thomas; Andersen, Anders

    2017-08-29

    Microbial filter feeders are an important group of grazers, significant to the microbial loop, aquatic food webs, and biogeochemical cycling. Our understanding of microbial filter feeding is poor, and, importantly, it is unknown what force microbial filter feeders must generate to process adequate amounts of water. Also, the trade-off in the filter spacing remains unexplored, despite its simple formulation: A filter too coarse will allow suitably sized prey to pass unintercepted, whereas a filter too fine will cause strong flow resistance. We quantify the feeding flow of the filter-feeding choanoflagellate Diaphanoeca grandis using particle tracking, and demonstrate that the current understanding of microbial filter feeding is inconsistent with computational fluid dynamics (CFD) and analytical estimates. Both approaches underestimate observed filtration rates by more than an order of magnitude; the beating flagellum is simply unable to draw enough water through the fine filter. We find similar discrepancies for other choanoflagellate species, highlighting an apparent paradox. Our observations motivate us to suggest a radically different filtration mechanism that requires a flagellar vane (sheet), something notoriously difficult to visualize but sporadically observed in the related choanocytes (sponges). A CFD model with a flagellar vane correctly predicts the filtration rate of D. grandis , and using a simple model we can account for the filtration rates of other microbial filter feeders. We finally predict how optimum filter mesh size increases with cell size in microbial filter feeders, a prediction that accords very well with observations. We expect our results to be of significance for small-scale biophysics and trait-based ecological modeling.

  13. Influence of habitat degradation on fish replenishment

    Science.gov (United States)

    McCormick, M. I.; Moore, J. A. Y.; Munday, P. L.

    2010-09-01

    Temperature-induced coral bleaching is a major threat to the biodiversity of coral reef ecosystems. While reductions in species diversity and abundance of fish communities have been documented following coral bleaching, the mechanisms that underlie these changes are poorly understood. The present study examined the impacts of coral bleaching on the early life-history processes of coral reef fishes. Daily monitoring of fish settlement patterns found that ten times as many fish settled to healthy coral than sub-lethally bleached coral. Species diversity of settling fishes was least on bleached coral and greatest on dead coral, with healthy coral having intermediate levels of diversity. Laboratory experiments using light-trap caught juveniles showed that different damselfish species chose among healthy, bleached and dead coral habitats using different combinations of visual and olfactory cues. The live coral specialist, Pomacentrus moluccensis, preferred live coral and avoided bleached and dead coral, using mostly visual cues to inform their habitat choice. The habitat generalist, Pomacentrus amboinensis, also preferred live coral and avoided bleached and dead coral but selected these habitats using both visual and olfactory cues. Trials with another habitat generalist, Dischistodus sp., suggested that vision played a significant role. A 20 days field experiment that manipulated densities of P. moluccensis on healthy and bleached coral heads found an influence of fish density on juvenile weight and growth, but no significant influence of habitat quality. These results suggests that coral bleaching will affect settlement patterns and species distributions by influencing the visual and olfactory cues that reef fish larvae use to make settlement choices. Furthermore, increased fish density within the remaining healthy coral habitats could play an important role in influencing population dynamics.

  14. Habitat connectivity and fragmented nuthatch populations in agricultural landscapes

    OpenAIRE

    Langevelde, van, F.

    1999-01-01

    In agricultural landscapes, the habitat of many species is subject to fragmentation. When the habitat of a species is fragmented and the distances between patches of habitat are large relative to the movement distances of the species, it can be expected that the degree of habitat connectivity affects processes at population and individual level. In this thesis, I report on a study of effects of habitat fragmentation and opportunities to mitigate these effects by planning ecological n...

  15. Habitat Suitability Index Models: Red-winged blackbird

    Science.gov (United States)

    Short, Henry L.

    1985-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the red-winged blackbird (Agelaius phoeniceus L.). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  16. Habitat Suitability Index Models: Yellow-headed blackbird

    Science.gov (United States)

    Schroeder, Richard L.

    1982-01-01

    Habitat preferences of the yellow-headed blackbird (Xanthocephalus xanthocephalus) are described in this publication. It is one of a series of Habitat Suitability Index (HSI) models and was developed through an analysis of available infomration on the species-habitat requirements of the species. Habitat use information is presented in a review of the literature, followed by the development of an HSI model, designed for use in impact assessment and habitat management activities.

  17. Spawning habitat of the Peruvian anchovy, Engraulis ringens

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, J.J. (Brookhaven National Lab., Upton, NY); Whitledge, T.E.; Esaias, W.E.; Smith, R.L.; Huntsman, S.A.; Santander, H.; De Mendiola, B.R.

    1980-01-01

    Individual larvae of the anchovy Engraulis ringens appear to survive better off the northern coast of Peru during the austral winter season when a motile algal food supply is available. Concentrations of the dinoflagellate food of the first feeding anchovy larvae may be reduced less often by wind events in the north than in the south. Under El Nino conditions, more of the adult anchovy are found south within a less favorable spawning habitat, in terms of dilution and food quality, where there is evidently less larval survival and subsequent recruitment to adult stocks. Increased mortality of the larvae during 1965, 1972, and 1976 El Ninos and of the adults during the 20-y fishery has reduced the present stock to less than 20% of its biomass in times of peak yield. Such a change in food chain dynamics is reflected in transients of oxygen demand at the decadal scale of variability. Associated with an increase in zooplankton biomass and a decline of the anchovy fishery, the sardine species of the clupeid pair off Peru may also be increasing in number, implying that natural oscillations of clupeoids may be accelerated by overfishing.

  18. Bacteria dialog with Santa Rosalia: Are aggregations of cosmopolitan bacteria mainly explained by habitat filtering or by ecological interactions?

    Science.gov (United States)

    Pascual-García, Alberto; Tamames, Javier; Bastolla, Ugo

    2014-12-04

    Since the landmark Santa Rosalia paper by Hutchinson, niche theory addresses the determinants of biodiversity in terms of both environmental and biological aspects. Disentangling the role of habitat filtering and interactions with other species is critical for understanding microbial ecology. Macroscopic biogeography explores hypothetical ecological interactions through the analysis of species associations. These methods have started to be incorporated into microbial ecology relatively recently, due to the inherent experimental difficulties and the coarse grained nature of the data. Here we investigate the influence of environmental preferences and ecological interactions in the tendency of bacterial taxa to either aggregate or segregate, using a comprehensive dataset of bacterial taxa observed in a wide variety of environments. We assess significance of taxa associations through a null model that takes into account habitat preferences and the global distribution of taxa across samples. The analysis of these associations reveals a surprisingly large number of significant aggregations between taxa, with a marked community structure and a strong propensity to aggregate for cosmopolitan taxa. Due to the coarse grained nature of our data we cannot conclusively reject the hypothesis that many of these aggregations are due to environmental preferences that the null model fails to reproduce. Nevertheless, some observations are better explained by ecological interactions than by habitat filtering. In particular, most pairs of aggregating taxa co-occur in very different environments, which makes it unlikely that these associations are due to habitat preferences, and many are formed by cosmopolitan taxa without well defined habitat preferences. Moreover, known cooperative interactions are retrieved as aggregating pairs of taxa. As observed in similar studies, we also found that phylogenetically related taxa are much more prone to aggregate than to segregate, an observation

  19. Effects of geoduck (Panopea generosa) aquaculture on resident and transient macrofauna communities of Puget Sound, Washington, USA

    Science.gov (United States)

    Mcdonald, P. Sean; Galloway, Aaron W.E.; McPeek, Kathleen C.; VanBlaricom, Glenn R.

    2015-01-01

    In Washington state, commercial culture of geoducks (Panopea generosa) involves large-scale out-planting of juveniles to intertidal habitats, and installation of PVC tubes and netting to exclude predators and increase early survival. Structures associated with this nascent aquaculture method are examined to determine whether they affect patterns of use by resident and transient macrofauna. Results are summarized from regular surveys of aquaculture operations and reference beaches in 2009 to 2011 at three sites during three phases of culture: (1) pregear (-geoducks, -structure), (2) gear present (+geoducks, +structures), and (3) postgear (+geoducks, -structures). Resident macroinvertebrates (infauna and epifauna) were sampled monthly (in most cases) using coring methods at low tide during all three phases. Differences in community composition between culture plots and reference areas were examined with permutational analysis of variance and homogeneity of multivariate dispersion tests. Scuba and shoreline transect surveys were used to examine habitat use by transient fish and macroinvertebrates. Analysis of similarity and complementary nonmetric multidimensional scaling were used to compare differences between species functional groups and habitat type during different aquaculture phases. Results suggest that resident and transient macrofauna respond differently to structures associated with geoduck aquaculture. No consistent differences in the community of resident macrofauna were observed at culture plots or reference areas at the three sites during any year. Conversely, total abundance of transient fish and macroinvertebrates were more than two times greater at culture plots than reference areas when aquaculture structures were in place. Community composition differed (analysis of similarity) between culture and reference plots during the gear-present phase, but did not persist to the next farming stage (postgear). Habitat complexity associated with shellfish

  20. Habitat connectivity as a metric for aquatic microhabitat quality: Application to Chinook salmon spawning habitat

    Science.gov (United States)

    Ryan Carnie; Daniele Tonina; Jim McKean; Daniel Isaak

    2016-01-01

    Quality of fish habitat at the scale of a single fish, at the metre resolution, which we defined here as microhabitat, has been primarily evaluated on short reaches, and their results have been extended through long river segments with methods that do not account for connectivity, a measure of the spatial distribution of habitat patches. However, recent...

  1. Separative performance transients in a gas centrifuge

    International Nuclear Information System (INIS)

    Olander, D.R.

    1979-01-01

    A general method has been developed to calculate the behavior of the exit compositions from a gas centrifuge under unsteady conditions. The method utilizes the basic enrichment gradient equations derived by Cohen, which, in this case, contain time derivatives of the partial 235 U inventories. These partial differential equations are converted to ordinary differential equations by a linear approximation to the axial concentration distribution for use in the inventory terms only. With this simplification, analytical solution is possible for the feed concentration transient. The transient driven by a change in the feed flow rate, however, requires numerical solution. For analysis of ideal cascades in the unsteady state, the transient flow and separation characteristics of the centrifuge must be combined with total uranium and 235 U material balances on each stage

  2. Transient effects in friction fractal asperity creep

    CERN Document Server

    Goedecke, Andreas

    2013-01-01

    Transient friction effects determine the behavior of a wide class of mechatronic systems. Classic examples are squealing brakes, stiction in robotic arms, or stick-slip in linear drives. To properly design and understand mechatronic systems of this type, good quantitative models of transient friction effects are of primary interest. The theory developed in this book approaches this problem bottom-up, by deriving the behavior of macroscopic friction surfaces from the microscopic surface physics. The model is based on two assumptions: First, rough surfaces are inherently fractal, exhibiting roughness on a wide range of scales. Second, transient friction effects are caused by creep enlargement of the real area of contact between two bodies. This work demonstrates the results of extensive Finite Element analyses of the creep behavior of surface asperities, and proposes a generalized multi-scale area iteration for calculating the time-dependent real contact between two bodies. The toolset is then demonstrated both...

  3. Transient response in granular bounded heap flows

    Science.gov (United States)

    Xiao, Hongyi; Ottino, Julio M.; Lueptow, Richard M.; Umbanhowar, Paul B.

    2017-11-01

    Heap formation, a canonical granular flow, is common in industry and is also found in nature. Here, we study the transition between steady flow states in quasi-2D bounded heaps by suddenly changing the feed rate from one fixed value to another. During the transition, in both experiments and discrete element method simulations, an additional wedge of flowing particles propagates over the rising free surface. The downstream edge of the wedge - the wedge front - moves downstream with velocity inversely proportional to the square root of time. An additional longer duration transient process continues after the wedge front reaches the downstream wall. The transient flux profile during the entire transition is well modeled by a diffusion-like equation derived from local mass balance and a local linear relation between the flux and the surface slope. Scalings for the transient kinematics during the flow transitions are developed based on the flux profiles. Funded by NSF Grant CBET-1511450.

  4. NALAP: an LMFBR system transient code

    International Nuclear Information System (INIS)

    Martin, B.A.; Agrawal, A.K.; Albright, D.C.; Epel, L.G.; Maise, G.

    1975-07-01

    NALAP is a LMFBR system transient code. This code, adapted from the light water reactor transient code RELAP 3B, simulates thermal-hydraulic response of sodium cooled fast breeder reactors when subjected to postulated accidents such as a massive pipe break as well as a variety of other upset conditions that do not disrupt the system geometry. Various components of the plant are represented by control volumes. These control volumes are connected by junctions some of which may be leak or fill junctions. The fluid flow equations are modeled as compressible, single-stream flow with momentum flux in one dimension. The transient response is computed by integrating the thermal-hydraulic conservation equations from user-initialized operating conditions by an implicit numerical scheme. Point kinetics approximation is used to represent the time dependent heat generation in the reactor core

  5. Modeling of environmentally induced transients within satellites

    Science.gov (United States)

    Stevens, N. John; Barbay, Gordon J.; Jones, Michael R.; Viswanathan, R.

    1987-01-01

    A technique is described that allows an estimation of possible spacecraft charging hazards. This technique, called SCREENS (spacecraft response to environments of space), utilizes the NASA charging analyzer program (NASCAP) to estimate the electrical stress locations and the charge stored in the dielectric coatings due to spacecraft encounter with a geomagnetic substorm environment. This information can then be used to determine the response of the spacecraft electrical system to a surface discharge by means of lumped element models. The coupling into the electronics is assumed to be due to magnetic linkage from the transient currents flowing as a result of the discharge transient. The behavior of a spinning spacecraft encountering a severe substorm is predicted using this technique. It is found that systems are potentially vulnerable to upset if transient signals enter through the ground lines.

  6. Transient risk factors of acute occupational injuries

    DEFF Research Database (Denmark)

    Østerlund, Anna H; Lander, Flemming; Nielsen, Kent

    2017-01-01

    Objectives The objectives of this study were to (i) identify transient risk factors of occupational injuries and (ii) determine if the risk varies with age, injury severity, job task, and industry risk level. Method A case-crossover design was used to examine the effect of seven specific transient...... risk factors (time pressure, disagreement with someone, feeling sick, being distracted by someone, non-routine task, altered surroundings, and broken machinery and materials) for occupational injuries. In the study, 1693 patients with occupational injuries were recruited from a total of 4002...... in relation to sex, age, job task, industry risk level, or injury severity. Conclusion Use of a case-crossover design identified several worker-related transient risk factors (time pressure, feeling sick, being distracted by someone) that led to significantly increased risks for occupational injuries...

  7. Positron beam studies of transients in semiconductors

    International Nuclear Information System (INIS)

    Beling, C.D.; Ling, C.C.; Cheung, C.K.; Naik, P.S.; Zhang, J.D.; Fung, S.

    2006-01-01

    Vacancy-sensing positron deep level transient spectroscopy (PDLTS) is a positron beam-based technique that seeks to provide information on the electronic ionization levels of vacancy defects probed by the positron through the monitoring of thermal transients. The experimental discoveries leading to the concept of vacancy-sensing PDLTS are first reviewed. The major problem associated with this technique is discussed, namely the strong electric fields establish in the near surface region of the sample during the thermal transient which tend to sweep positrons into the contact with negligible defect trapping. New simulations are presented which suggest that under certain conditions a sufficient fraction of positrons may be trapped into ionizing defects rendering PDLTS technique workable. Some suggestions are made for techniques that might avoid the problematic electric field problem, such as optical-PDLTS where deep levels are populated using light and the use of high forward bias currents for trap filling

  8. Transient Exciplex Formation Electron Transfer Mechanism

    Directory of Open Access Journals (Sweden)

    Michael G. Kuzmin

    2011-01-01

    Full Text Available Transient exciplex formation mechanism of excited-state electron transfer reactions is analyzed in terms of experimental data on thermodynamics and kinetics of exciplex formation and decay. Experimental profiles of free energy, enthalpy, and entropy for transient exciplex formation and decay are considered for several electron transfer reactions in various solvents. Strong electronic coupling in contact pairs of reactants causes substantial decrease of activation energy relative to that for conventional long-range ET mechanism, especially for endergonic reactions, and provides the possibility for medium reorganization concatenated to gradual charge shift in contrast to conventional preliminary medium and reactants reorganization. Experimental criteria for transient exciplex formation (concatenated mechanism of excited-state electron transfer are considered. Available experimental data show that this mechanism dominates for endergonic ET reactions and provides a natural explanation for a lot of known paradoxes of ET reactions.

  9. Turbofan compressor dynamics during afterburner transients

    Science.gov (United States)

    Kurkov, A. P.

    1976-01-01

    The effects of afterburner light-off and shut-down transients on the compressor stability are investigated. The reported experimental results are based on detailed high response pressure and temperature measurements on the TF30-P-3 turbofan engine. The tests were performed in an altitude test chamber simulating high altitude engine operation. It is shown that during both types of transients, flow breaks down in the forward part of the fan bypass duct. At a sufficiently low engine inlet pressure this resulted in a compressor stall. Complete flow breakdown within the compressor was preceded by a rotating stall. At some locations in the compressor, rotating stall cells initially extended only through part of the blade span. For the shutdown transient the time between first and last detected occurrence of rotating stall is related to the flow Reynolds number. An attempt was made to deduce the number and speed of propagation of rotating stall cells.

  10. Characterization of electrical appliances in transient state

    Science.gov (United States)

    Wójcik, Augustyn; Winiecki, Wiesław

    2017-08-01

    The article contains the study about electrical appliance characterization on the basis of power grid signals. To represent devices, parameters of current and voltage signals recorded during transient states are used. In this paper only transients occurring as a result of switching on devices are considered. The way of data acquisition performed in specialized measurement setup developed for electricity load monitoring is described. The paper presents the method of transients detection and the method of appliance parameters calculation. Using the set of acquired measurement data and appropriate software the set of parameters for several household appliances operating in different operating conditions was processed. Usefulness of appliances characterization in Non-Intrusive Appliance Load Monitoring System (NIALMS) with the use of proposed method is discussed focusing on obtained results.

  11. MICROBIAL SURFACTANTS IN ENVIRONMENTAL TECHNOLOGIES

    Directory of Open Access Journals (Sweden)

    T. P. Pirog

    2015-08-01

    Full Text Available It was shown literature and own experimental data concerning the use of microbial surface active glycolipids (rhamno-, sophoro- and trehalose lipids and lipopeptides for water and soil purification from oil and other hydrocarbons, removing toxic heavy metals (Cu2+, Cd2+, Ni2+, Pb2+, degradation of complex pollution (oil and other hydrocarbons with heavy metals, and the role of microbial surfactants in phytoremediation processes. The factors that limit the use of microbial surfactants in environmental technologies are discussed. Thus, at certain concentrations biosurfactant can exhibit antimicrobial properties and inhibit microorganisms destructing xenobiotics. Microbial biodegradability of surfactants may also reduce the effectiveness of bioremediation. Development of effective technologies using microbial surfactants should include the following steps: monitoring of contaminated sites to determine the nature of pollution and analysis of the autochthonous microbiota; determining the mode of surfactant introduction (exogenous addition of stimulation of surfactant synthesis by autochthonous microbiota; establishing an optimal concentration of surfactant to prevent exhibition of antimicrobial properties and rapid biodegradation; research both in laboratory and field conditions.

  12. Managing harvest and habitat as integrated components

    Science.gov (United States)

    Osnas, Erik; Runge, Michael C.; Mattsson, Brady J.; Austin, Jane E.; Boomer, G. S.; Clark, R. G.; Devers, P.; Eadie, J. M.; Lonsdorf, E. V.; Tavernia, Brian G.

    2014-01-01

    In 2007, several important initiatives in the North American waterfowl management community called for an integrated approach to habitat and harvest management. The essence of the call for integration is that harvest and habitat management affect the same resources, yet exist as separate endeavours with very different regulatory contexts. A common modelling framework could help these management streams to better understand their mutual effects. Particularly, how does successful habitat management increase harvest potential? Also, how do regional habitat programmes and large-scale harvest strategies affect continental population sizes (a metric used to express habitat goals)? In the ensuing five years, several projects took on different aspects of these challenges. While all of these projects are still on-going, and are not yet sufficiently developed to produce guidance for management decisions, they have been influential in expanding the dialogue and producing some important emerging lessons. The first lesson has been that one of the more difficult aspects of integration is not the integration across decision contexts, but the integration across spatial and temporal scales. Habitat management occurs at local and regional scales. Harvest management decisions are made at a continental scale. How do these actions, taken at different scales, combine to influence waterfowl population dynamics at all scales? The second lesson has been that consideration of the interface of habitat and harvest management can generate important insights into the objectives underlying the decision context. Often the objectives are very complex and trade-off against one another. The third lesson follows from the second – if an understanding of the fundamental objectives is paramount, there is no escaping the need for a better understanding of human dimensions, specifically the desires of hunters and nonhunters and the role they play in conservation. In the end, the compelling question is

  13. Exploitation of microbial antagonists for the control of postharvest diseases of fruits: a review.

    Science.gov (United States)

    Dukare, Ajinath Shridhar; Paul, Sangeeta; Nambi, V Eyarkai; Gupta, Ram Kishore; Singh, Rajbir; Sharma, Kalyani; Vishwakarma, Rajesh Kumar

    2018-01-16

    Fungal diseases result in significant losses of fruits and vegetables during handling, transportation and storage. At present, post-production fungal spoilage is predominantly controlled by using synthetic fungicides. Under the global climate change scenario and with the need for sustainable agriculture, biological control methods of fungal diseases, using antagonistic microorganisms, are emerging as ecofriendly alternatives to the use of fungicides. The potential of microbial antagonists, isolated from a diversity of natural habitats, for postharvest disease suppression has been investigated. Postharvest biocontrol systems involve tripartite interaction between microbial antagonists, the pathogen and the host, affected by environmental conditions. Several modes for fungistatic activities of microbial antagonists have been suggested, including competition for nutrients and space, mycoparasitism, secretion of antifungal antibiotics and volatile metabolites and induction of host resistance. Postharvest application of microbial antagonists is more successful for efficient disease control in comparison to pre-harvest application. Attempts have also been made to improve the overall efficacy of antagonists by combining them with different physical and chemical substances and methods. Globally, many microbe-based biocontrol products have been developed and registered for commercial use. The present review provides a brief overview on the use of microbial antagonists as postharvest biocontrol agents and summarises information on their isolation, mechanisms of action, application methods, efficacy enhancement, product formulation and commercialisation.

  14. Microbial ecology of the salmon necrobiome: evidence salmon carrion decomposition influences aquatic and terrestrial insect microbiomes.

    Science.gov (United States)

    Pechal, Jennifer L; Benbow, M Eric

    2016-05-01

    Carrion decomposition is driven by complex relationships that affect necrobiome community (i.e. all organisms and their genes associated with a dead animal) interactions, such as insect species arrival time to carrion and microbial succession. Little is understood about how microbial communities interact with invertebrates at the aquatic-terrestrial habitat interface. The first objective of the study was to characterize internal microbial communities using high-throughput sequencing of 16S rRNA gene amplicons for aquatic insects (three mayfly species) in streams with salmon carcasses compared with those in streams without salmon carcasses. The second objective was to assess the epinecrotic microbial communities of decomposing salmon carcasses (Oncorhynchus keta) compared with those of terrestrial necrophagous insects (Calliphora terraenovae larvae and adults) associated with the carcasses. There was a significant difference in the internal microbiomes of mayflies collected in salmon carcass-bearing streams and in non-carcass streams, while the developmental stage of blow flies was the governing factor in structuring necrophagous insect internal microbiota. Furthermore, the necrophagous internal microbiome was influenced by the resource on which the larvae developed, and changes in the adult microbiome varied temporally. Overall, these carrion subsidy-driven networks respond to resource pulses with bottom-up effects on consumer microbial structure, as revealed by shifting communities over space and time. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  15. Towards a universal microbial inoculum for dissolved organic carbon degradation experiments

    Science.gov (United States)

    Pastor, Ada; Catalán, Núria; Gutiérrez, Carmen; Nagar, Nupur; Casas-Ruiz, Joan P.; Obrador, Biel; von Schiller, Daniel; Sabater, Sergi; Petrovic, Mira; Borrego, Carles M.; Marcé, Rafael

    2017-04-01

    Dissolved organic carbon (DOC) is the largest biologically available pool of organic carbon in aquatic ecosystems and its degradation along the land-to-ocean continuum has implications for carbon cycling from local to global scales. DOC biodegradability is usually assessed by incubating filtered water inoculated with native microbial assemblages in the laboratory. However, the use of a native inoculum from several freshwaters, without having a microbial-tailored design, hampers our ability to tease apart the relative contribution of the factors driving DOC degradation from the effects of local microbial communities. The use of a standard microbial inoculum would allow researchers to disentangle the drivers of DOC degradation from the metabolic capabilities of microbial communities operating in situ. With this purpose, we designed a bacterial inoculum to be used in experiments of DOC degradation in freshwater habitats. The inoculum is composed of six bacterial strains that easily grow under laboratory conditions, possess a versatile metabolism and are able to grow under both aerobic and anaerobic conditions. The mixed inoculum showed higher DOC degradation rates than those from their isolated bacterial components and the consumption of organic substrates was consistently replicated. Moreover, DOC degradation rates obtained using the designed inoculum were responsive across a wide range of natural water types differing in DOC concentration and composition. Overall, our results show the potential of the designed inoculum as a tool to discriminate between the effects of environmental drivers and intrinsic properties of DOC on degradation dynamics.

  16. Methodological flaws introduce strong bias into molecular analysis of microbial populations.

    Science.gov (United States)

    Krakat, N; Anjum, R; Demirel, B; Schröder, P

    2017-02-01

    In this study, we report how different cell disruption methods, PCR primers and in silico analyses can seriously bias results from microbial population studies, with consequences for the credibility and reproducibility of the findings. Our results emphasize the pitfalls of commonly used experimental methods that can seriously weaken the interpretation of results. Four different cell lysis methods, three commonly used primer pairs and various computer-based analyses were applied to investigate the microbial diversity of a fermentation sample composed of chicken dung. The fault-prone, but still frequently used, amplified rRNA gene restriction analysis was chosen to identify common weaknesses. In contrast to other studies, we focused on the complete analytical process, from cell disruption to in silico analysis, and identified potential error rates. This identified a wide disagreement of results between applied experimental approaches leading to very different community structures depending on the chosen approach. The interpretation of microbial diversity data remains a challenge. In order to accurately investigate the taxonomic diversity and structure of prokaryotic communities, we suggest a multi-level approach combining DNA-based and DNA-independent techniques. The identified weaknesses of commonly used methods to study microbial diversity can be overcome by a multi-level approach, which produces more reliable data about the fate and behaviour of microbial communities of engineered habitats such as biogas plants, so that the best performance can be ensured. © 2016 The Society for Applied Microbiology.

  17. Seasonal Analysis of Microbial Communities in Precipitation in the Greater Tokyo Area, Japan

    Directory of Open Access Journals (Sweden)

    Satoshi Hiraoka

    2017-08-01

    Full Text Available The presence of microbes in the atmosphere and their transport over long distances across the Earth's surface was recently shown. Precipitation is likely a major path by which aerial microbes fall to the ground surface, affecting its microbial ecosystems and introducing pathogenic microbes. Understanding microbial communities in precipitation is of multidisciplinary interest from the perspectives of microbial ecology and public health; however, community-wide and seasonal analyses have not been conducted. Here, we carried out 16S rRNA amplicon sequencing of 30 precipitation samples that were aseptically collected over 1 year in the Greater Tokyo Area, Japan. The precipitation microbial communities were dominated by Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria and were overall consistent with those previously reported in atmospheric aerosols and cloud water. Seasonal variations in composition were observed; specifically, Proteobacteria abundance significantly decreased from summer to winter. Notably, estimated ordinary habitats of precipitation microbes were dominated by animal-associated, soil-related, and marine-related environments, and reasonably consistent with estimated air mass backward trajectories. To our knowledge, this is the first amplicon-sequencing study investigating precipitation microbial communities involving sampling over the duration of a year.

  18. Transient Seepage for Levee Engineering Analyses

    Science.gov (United States)

    Tracy, F. T.

    2017-12-01

    Historically, steady-state seepage analyses have been a key tool for designing levees by practicing engineers. However, with the advances in computer modeling, transient seepage analysis has become a potentially viable tool. A complication is that the levees usually have partially saturated flow, and this is significantly more complicated in transient flow. This poster illustrates four elements of our research in partially saturated flow relating to the use of transient seepage for levee design: (1) a comparison of results from SEEP2D, SEEP/W, and SLIDE for a generic levee cross section common to the southeastern United States; (2) the results of a sensitivity study of varying saturated hydraulic conductivity, the volumetric water content function (as represented by van Genuchten), and volumetric compressibility; (3) a comparison of when soils do and do not exhibit hysteresis, and (4) a description of proper and improper use of transient seepage in levee design. The variables considered for the sensitivity and hysteresis studies are pore pressure beneath the confining layer at the toe, the flow rate through the levee system, and a levee saturation coefficient varying between 0 and 1. Getting results for SEEP2D, SEEP/W, and SLIDE to match proved more difficult than expected. After some effort, the results matched reasonably well. Differences in results were caused by various factors, including bugs, different finite element meshes, different numerical formulations of the system of nonlinear equations to be solved, and differences in convergence criteria. Varying volumetric compressibility affected the above test variables the most. The levee saturation coefficient was most affected by the use of hysteresis. The improper use of pore pressures from a transient finite element seepage solution imported into a slope stability computation was found to be the most grievous mistake in using transient seepage in the design of levees.

  19. Transient behaviour of small HTR for cogeneration

    International Nuclear Information System (INIS)

    Verkerk, E.C.; Van Heek, A.I.

    2000-01-01

    The Dutch market for combined generation of heat and power identifies a unit size of 40 MW thermal for the conceptual design of a nuclear cogeneration plant. The ACACIA system provides 14 MWe electricity combined with 17 t/h of high temperature steam (220 deg C, 10 bar) with a pebble-bed high temperature reactor directly coupled with a helium compressor and a helium turbine. The design of this small CHP unit that is used for industrial applications is mainly based on a pre-feasibility study in 1996, performed by a joint working group of five Dutch organisations, in which technical feasibility was shown. Thermal hydraulic and reactor physics analyses show favourable control characteristics during normal operation and a benign response to loss of helium coolant and loss of flow conditions. Throughout the response on these highly infrequent conditions, ample margin exists between the highest fuel temperatures and the temperature above which fuel degradation will occur. To come to quantitative statements about the ACACIA transient behaviour, a calculational coupling between the high temperature reactor core analysis code package PANTHER/DIREKT and the thermal hydraulic code RELAP5 for the energy conversion system has been made. This coupling offers a more realistic simulation of the entire system, since it removes the necessity of forcing boundary conditions on the simulation models at the data transfer points. In this paper, the models used for the dynamic components of the energy conversion system are described, and the results of the calculation for two operational transients in order to demonstrate the effects of the interaction between reactor core and its energy conversion system are shown. Several transient cases that are representative as operational transients for an HTR will be discussed, including one representing a load rejection case that shows the functioning of the control system, in particular the bypass valve. Another transient is a load following

  20. An index of reservoir habitat impairment

    Science.gov (United States)

    Miranda, L.E.; Hunt, K.M.

    2011-01-01

    Fish habitat impairment resulting from natural and anthropogenic watershed and in-lake processes has in many cases reduced the ability of reservoirs to sustain native fish assemblages and fisheries quality. Rehabilitation of impaired reservoirs is hindered by the lack of a method suitable for scoring impairment status. To address this limitation, an index of reservoir habitat impairment (IRHI) was developed by merging 14 metrics descriptive of common impairment sources, with each metric scored from 0 (no impairment) to 5 (high impairment) by fisheries scientists with local knowledge. With a plausible range of 5 to 25, distribution of the IRHI scores ranged from 5 to 23 over 482 randomly selected reservoirs dispersed throughout the USA. The IRHI reflected five impairment factors including siltation, structural habitat, eutrophication, water regime, and aquatic plants. The factors were weakly related to key reservoir characteristics including reservoir area, depth, age, and usetype, suggesting that common reservoir descriptors are poor predictors of fish habitat impairment. The IRHI is rapid and inexpensive to calculate, provides an easily understood measure of the overall habitat impairment, allows comparison of reservoirs and therefore prioritization of restoration activities, and may be used to track restoration progress. The major limitation of the IRHI is its reliance on unstandardized professional judgment rather than standardized empirical measurements. ?? 2010 US Government.