363 research outputs found
The JCMT Gould Belt Survey: the effect of molecular contamination in SCUBA-2 observations of Orion A
Thermal emission from cold dust grains in giant molecular clouds can be used
to probe the physical properties, such as density, temperature and emissivity
in star-forming regions. We present the SCUBA-2 shared-risk observations at 450
m and 850 m of the Orion A molecular cloud complex taken at the James
Clerk Maxwell Telescope (JCMT). Previous studies showed that molecular emission
lines can contribute significantly to the measured fluxes in those continuum
bands. We use the HARP CO J=3-2 integrated intensity map for Orion A in
order to evaluate the molecular line contamination and its effects on the
SCUBA-2 maps. With the corrected fluxes, we have obtained a new spectral index
map for the thermal emission of dust in the well-known integral-shaped
filament. Furthermore, we compare a sample of 33 sources, selected over the
Orion A molecular cloud complex for their high CO J=3-2 line
contamination, to 27 previously identified clumps in OMC-4. This allows us to
quantify the effect of line contamination on the ratio of 850 m to 450
m flux densities and how it modifies the deduced spectral index of
emissivity for the dust grains. We also show that at least one
Spitzer-identified protostellar core in OMC-5 has a CO J=3-2
contamination level of 16 %. Furthermore, we find the strongest contamination
level (44 %) towards a young star with disk near OMC-2. This work is part of
the JCMT Gould Belt Legacy Survey.Comment: 13 pages, 6 figures, Accepted for publication in Monthly Notices of
the Royal Astronomical Society (MNRAS
Feeding, Bonding, and the Formation of Social Relationships. Ethnographic Challenges to Attachment Theory and Early Childhood Interventions
This Element explores multi-faceted linkages between feeding and relationship formation based on ethnographic case studies in Morocco, Madagascar, Sri Lanka, Taiwan, and Costa Rica. Research demonstrates that there are many culturally valued ways of feeding children, contradicting the idea of a single universally optimal feeding standard. It demonstrates further that in many parts of the world, feeding plays a central role in bonding and relationship formation, something largely overlooked in current developmental theories. Analysis shows that feeding contributes to relationship formation through what we call proximal, transactional, and distal dimensions. This Element argues that feeding practices can lead to qualitatively distinct forms of relationships. It has important theoretical and practical implications, calling for the expansion of attachment theory to include feeding and body-centered caregiving and significant changes to global interventions currently based on 'responsive feeding.' This title is also available as Open Access on Cambridge Core
The JCMT Gould Belt Survey: the effect of molecular contamination in SCUBA-2 observations of Orion A
JOURThis is the final version of the article. It was first published by Oxford Journals for the Royal Astronomical Society via http://dx.doi.org/ 10.1093/mnras/stv3009Thermal emission from cold dust grains in giant molecular clouds can be used to probe the physical properties, such as density, temperature and emissivity in star-forming regions. We present the Submillimetre Common-User Bolometer Array (SCUBA-2) shared-risk observations at 450 and 850 μm of the Orion A molecular cloud complex taken at the James Clerk Maxwell Telescope (JCMT). Previous studies showed that molecular emission lines can contribute significantly to the measured fluxes in those continuum bands. We use the Heterodyne Array Receiver Programme 12CO J = 3-2 integrated intensity map for Orion A in order to evaluate the molecular line contamination and its effects on the SCUBA-2 maps. With the corrected fluxes, we have obtained a new spectral index α map for the thermal emission of dust in the well-known integral-shaped filament. Furthermore, we compare a sample of 33 sources, selected over the Orion A molecular cloud complex for their high 12CO J = 3-2 line contamination, to 27 previously identified clumps in OMC 4. This allows us to quantify the effect of line contamination on the ratio of 850-450 μm flux densities and how it modifies the deduced spectral index of emissivity β for the dust grains. We also show that at least one Spitzer-identified protostellar core in OMC 5 has a 12CO J = 3-2 contamination level of 16 per cent. Furthermore, we find the strongest contamination level (44 per cent) towards a young star with disc near OMC 2. This work is part of the JCMT Gould Belt Legacy Survey
Efficient boron removal by using mesoporous matrices grafted with saccharides
Highly efficient boron removal from water was achieved by using mesoporous silica materials functionalised with saccharides.Beltran Porter, Daniel, [email protected] ; Amoros del Toro, Pedro Jose, [email protected]
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Sediment erosion and transport at the Rio Grande mouth : report for the National Border Technology Program and International Boundary and Water Commission.
The mouth of the Rio Grande has become silted up, obstructing its flow into the Gulf of Mexico. This is problematic in that it has created extensive flooding. The purpose of this study was to determine the erosion and transport potential of the sediments obstructing the flow of the Rio Grande by employing a unique Mobile High Shear Stress flume developed by Sandia's Carlsbad Programs Group for the US Army Corps of Engineers. The flume measures in-situ sediment erosion properties at shear stresses ranging from normal flow to flood conditions for a variable depth sediment core. The flume is in a self-contained trailer that can be placed on site in the field. Erosion rates and sediment grain size distributions were determined from sediment samples collected in and around the obstruction and were subsequently used to characterize the erosion potential of the sediments under investigation
TRY plant trait database - enhanced coverage and open access
Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives
Soil resource supply influences faunal size–specific distributions in natural food webs
The large range of body-mass values of soil organisms provides a tool to assess the ecological organization of soil communities. The goal of this paper is to identify graphical and quantitative indicators of soil community composition and ecosystem functioning, and to illustrate their application to real soil food webs. The relationships between log-transformed mass and abundance of soil organisms in 20 Dutch meadows and heathlands were investigated. Using principles of allometry, maximal use can be made of ecological theory to build and explain food webs. The aggregate contribution of small invertebrates such as nematodes to the entire community is high under low soil phosphorus content and causes shifts in the mass–abundance relationships and in the trophic structures. We show for the first time that the average of the trophic link lengths is a reliable predictor for assessing soil fertility responses. Ordered trophic link pairs suggest a self-organizing structure of food webs according to resource availability and can predict environmental shifts in ecologically meaningful ways
HUS and atypical HUS
Hemolytic uremic syndrome (HUS) is a thrombotic microangiopathy characterized by intravascular hemolysis, thrombocytopenia, and acute kidney failure. HUS is usually categorized as typical, caused by Shiga toxin-producing Escherichia coli (STEC) infection, as atypical HUS (aHUS), usually caused by uncontrolled complement activation, or as secondary HUS with a coexisting disease. In recent years, a general understanding of the pathogenetic mechanisms driving HUS has increased. Typical HUS (ie, STEC-HUS) follows a gastrointestinal infection with STEC, whereas aHUS is associated primarily with mutations or autoantibodies leading to dysregulated complement activation. Among the 30% to 50% of patients with HUS who have no detectable complement defect, some have either impaired diacylglycerol kinase epsilon (DGK epsilon) activity, cobalamin C deficiency, or plasminogen deficiency. Some have secondary HUS with a coexisting disease or trigger such as autoimmunity, transplantation, cancer, infection, certain cytotoxic drugs, or pregnancy. The common pathogenetic features in STEC-HUS, aHUS, and secondary HUS are simultaneous damage to endothelial cells, intravascular hemolysis, and activation of platelets leading to a procoagulative state, formation of microthrombi, and tissue damage. In this review, the differences and similarities in the pathogenesis of STEC-HUS, aHUS, and secondaryHUSare discussed. Commonfor the pathogenesis seems to be the vicious cycle of complement activation, endothelial cell damage, platelet activation, and thrombosis. This process can be stopped by therapeutic complement inhibition in most patients with aHUS, but usually not those with a DGK epsilon mutation, and some patients with STEC-HUS or secondary HUS. Therefore, understanding the pathogenesis of the different forms of HUS may prove helpful in clinical practice.Peer reviewe
The Effect of Consumers and Mutualists of Vaccinium membranaceum at Mount St. Helens: Dependence on Successional Context
In contrast to secondary succession, studies of terrestrial primary succession largely ignore the role of biotic interactions, other than plant facilitation and competition, despite the expectation that simplified interaction webs and propagule-dependent demographics may amplify the effects of consumers and mutualists. We investigated whether successional context determined the impact of consumers and mutualists by quantifying their effects on reproduction by the shrub Vaccinium membranaceum in primary and secondary successional sites at Mount St. Helens (Washington, USA), and used simulations to explore the effects of these interactions on colonization. Species interactions differed substantially between sites, and the combined effect of consumers and mutualists was much more strongly negative for primary successional plants. Because greater local control of propagule pressure is expected to increase successional rates, we evaluated the role of dispersal in the context of these interactions. Our simulations showed that even a small local seed source greatly increases population growth rates, thereby balancing strong consumer pressure. The prevalence of strong negative interactions in the primary successional site is a reminder that successional communities will not exhibit the distribution of interaction strengths characteristic of stable communities, and suggests the potential utility of modeling succession as the consequence of interaction strengths
Trade-offs between vegetative growth and acorn production in Quercus lobata during a mast year: the relevance of crop size and hierarchical level within the canopy
The concept of trade-offs between reproduction and other fitness traits is a fundamental principle of life history theory. For many plant species, the cost of sexual reproduction affects vegetative growth in years of high seed production through the allocation of resources to reproduction at different hierarchical levels of canopy organization. We have examined these tradeoffs at the shoot and branch level in an endemic California oak, Quercus lobata, during a mast year. To determine whether acorn production caused a reduction in vegetative growth, we studied trees that were high and low acorn producers, respectively. We observed that in both low and high acorn producers, shoots without acorns located adjacent to reproductive shoots showed reduced vegetative growth but that reduced branch-level growth on acorn-bearing branches occurred only in low acorn producers. The availability of local resources, measured as previous year growth, was the main factor determining acorn biomass. These findings show that the costs of reproduction varied among hierarchical levels, suggesting some degree of physiological autonomy of shoots in terms of acorn production. Costs also differed among trees with different acorn crops, suggesting that trees with large acorn crops had more available resources to allocate for growth and acorn production and to compensate for immediate local costs of seed production. These findings provide new insight into the proximate mechanisms for mast-seeding as a reproductive strategy
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