1,036 research outputs found
Color changes upon cooling of Lepidoptera scales containing photonic nanoarchitectures, and a method for identifying the changes
The effects produced by the condensation of water vapor from the environment in the various intricate
nanoarchitectures occurring in the wing scales of several Lepidoptera species were
investigated by controlled cooling (from 23° C, room temperature to -5 to -10° C) combined with
in situ measurements of changes in the reflectance spectra. It was determined that all photonic
nanoarchitectures giving a reflectance maximum in the visible range and having an open
nanostructure exhibited alteration of the position of the reflectance maximum associated with the
photonic nanoarchitectures. The photonic nanoarchitectures with a closed structure exhibited little
to no alteration in color. Similarly, control specimens colored by pigments did not exhibit a
color change under the same conditions. Hence, this method can be used to identify species with
open photonic nanoarchitectures in their scales. For certain species, an almost complete disappearance
of the reflectance maximum was found. All specimens recovered their original colors
following warming and drying. Cooling experiments using thin copper wires demonstrated that
color alterations could be limited to a width of a millimeter or less. Dried museum specimens did
not exhibit color changes when cooled in the absence of a heat sink due to the low heat capacity
of the wings
Parent perceived barriers and facilitators of children's adventurous play in Britain: a framework analysis
This is the final version. Available on open access from BMC via the DOI in this recordAvailability of data and materials:
The data obtained and analysed in the current study are available via the following link:
https://doi.org/10.5255/UKDA-SN-8793-1.BACKGROUND: From a public health perspective there is growing interest in children's play, including play involving risk and adventure, in relation to children's physical and mental health. Regarding mental health, it is theorised that adventurous play, where children experience thrilling, exciting emotions, offers important learning opportunities that prepare children for dealing with uncertainty and help prevent anxiety. Despite these benefits, adventurous play has decreased substantially within a generation. Parents have a key role in facilitating or limiting children's opportunities for adventurous play, but research identifying the barriers and facilitators parents perceive in relation to adventurous play is scarce. The present study therefore examined the barriers to and facilitators of adventurous play as perceived by parents of school-aged children in Britain. METHODS: This study analysed data from a subsample of parents in Britain (nâ=â377) who participated in the nationally representative British Children's Play Survey. Parents responded to two open-ended questions pertaining to the barriers to and facilitators of children's adventurous play. Responses were analysed using a qualitative Framework Analysis, an approach suitable for managing large datasets with specific research questions. RESULTS: Four framework categories were identified: Social Environment; Physical Environment; Risk of Injury; Child Factors. Social Environment included barriers and facilitators related to parents, family and peers, as well as community and society. Dominant themes within the Social Environment related to perceptions about the certainty of child safety, such as supervision and the safety of society. Beliefs about the benefits of adventurous play for development and well-being were also important in the Social Environment. Physical Environment factors focused on safety and practical issues. Risk of Injury captured concerns about children being injured during play. Child Factors included child attributes, such as play preference, developmental ability and trait-like characteristics. CONCLUSIONS: Improved understanding of what influences parent perceptions of adventurous play can inform public health interventions designed to improve children's opportunities for and engagement in adventurous play, with a view to promote children's physical and mental health.Economic and Social Research Council (ESRC)UKR
Characterisation of the Immunophenotype of Dogs with Primary Immune-Mediated Haemolytic Anaemia
Immune-mediated haemolytic anaemia (IMHA) is reported to be the most common autoimmune disease of dogs, resulting in significant morbidity and mortality in affected animals. Haemolysis is caused by the action of autoantibodies, but the immunological changes that result in their production have not been elucidated.To investigate the frequency of regulatory T cells (Tregs) and other lymphocyte subsets and to measure serum concentrations of cytokines and peripheral blood mononuclear cell expression of cytokine genes in dogs with IMHA, healthy dogs and dogs with inflammatory diseases.19 dogs with primary IMHA, 22 dogs with inflammatory diseases and 32 healthy control dogs.Residual EDTA-anti-coagulated blood samples were stained with fluorophore-conjugated monoclonal antibodies and analysed by flow cytometry to identify Tregs and other lymphocyte subsets. Total RNA was also extracted from peripheral blood mononuclear cells to investigate cytokine gene expression, and concentrations of serum cytokines (interleukins 2, 6 10, CXCL-8 and tumour necrosis factor α) were measured using enhanced chemiluminescent assays. Principal component analysis was used to investigate latent variables that might explain variability in the entire dataset.There was no difference in the frequency or absolute numbers of Tregs among groups, nor in the proportions of other lymphocyte subsets. The concentrations of pro-inflammatory cytokines were greater in dogs with IMHA compared to healthy controls, but the concentration of IL-10 and the expression of cytokine genes did not differ between groups. Principal component analysis identified four components that explained the majority of the variability in the dataset, which seemed to correspond to different aspects of the immune response.The immunophenotype of dogs with IMHA differed from that of dogs with inflammatory diseases and from healthy control dogs; some of these changes could suggest abnormalities in peripheral tolerance that permit development of autoimmune disease. The frequency of Tregs did not differ between groups, suggesting that deficiency in the number of these cells is not responsible for development of IMHA
Colony-level differences in the scaling rules governing wood ant compound eye structure
Differential organ growth during development is essential for adults to maintain the correct proportions and achieve their characteristic shape. Organs scale with body size, a process known as allometry that has been studied extensively in a range of organisms. Such scaling rules, typically studied from a limited sample, are assumed to apply to all members of a population and/or species. Here we study scaling in the compound eyes of workers of the wood ant, Formica rufa, from different colonies within a single population. Workers' eye area increased with body size in all the colonies showing a negative allometry. However, both the slope and intercept of some allometric scaling relationships differed significantly among colonies. Moreover, though mean facet diameter and facet number increased with body size, some colonies primarily increased facet number whereas others increased facet diameter, showing that the cellular level processes underlying organ scaling differed among colonies. Thus, the rules that govern scaling at the organ and cellular levels can differ even within a single population
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Rarity of monodominance in hyperdiverse Amazonian forests.
Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the treesââ„â10âcm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors
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Pre-Columbian land use in the ring-ditch region of the Bolivian Amazon
The nature and extent of pre-Columbian (pre-1492 AD) human impact in Amazonia is a contentious issue. The Bolivian Amazon has yielded some of the most impressive evidence for large and complex pre-Columbian societies in the Amazon basin, yet there remains relatively little data concerning the land use of these societies over time. Palaeoecology, when integrated with archaeological
data, has the potential to fill these gaps in our knowledge. We present a 6,000-year record of anthropogenic burning, agriculture and vegetation change, from an oxbow lake located adjacent to a pre-Columbian ring-ditch in north-east Bolivia (13°15â44â S, 63°42â37â W). Human occupation around the lake site is inferred from pollen and phytoliths of maize (Zea mays L.) and macroscopic charcoal evidence of anthropogenic burning. First occupation around the lake was radiocarbon dated to ~2500 years BP. The persistence of maize in the record from ~1850 BP suggests that it was an important crop grown in the ringditch region in pre-Columbian times, and abundant macroscopic charcoal suggests that pre-Columbian land management entailed more extensive burning of the landscape than the slash-and-burn agriculture practised around the site today. The site was occupied continuously until near-modern times, although there is evidence for a decline in agricultural intensity or change in land use strategy, and possible population decline, from ~600-500 BP. The long and continuous occupation, which predates the establishment of rainforest in the region, suggests that pre-Columbian land use may have had a significant
influence on ecosystem development at this site over the last ~2000 years
Aberrant lipid metabolism disrupts calcium homeostasis causing liver endoplasmic reticulum stress in obesity.
The endoplasmic reticulum (ER) is the main site of protein and lipid synthesis, membrane biogenesis, xenobiotic detoxification and cellular calcium storage, and perturbation of ER homeostasis leads to stress and the activation of the unfolded protein response. Chronic activation of ER stress has been shown to have an important role in the development of insulin resistance and diabetes in obesity. However, the mechanisms that lead to chronic ER stress in a metabolic context in general, and in obesity in particular, are not understood. Here we comparatively examined the proteomic and lipidomic landscape of hepatic ER purified from lean and obese mice to explore the mechanisms of chronic ER stress in obesity. We found suppression of protein but stimulation of lipid synthesis in the obese ER without significant alterations in chaperone content. Alterations in ER fatty acid and lipid composition result in the inhibition of sarco/endoplasmic reticulum calcium ATPase (SERCA) activity and ER stress. Correcting the obesity-induced alteration of ER phospholipid composition or hepatic Serca overexpression in vivo both reduced chronic ER stress and improved glucose homeostasis. Hence, we established that abnormal lipid and calcium metabolism are important contributors to hepatic ER stress in obesity
Added Value Measures in Education Show Genetic as Well as Environmental Influence
Does achievement independent of ability or previous attainment provide a purer measure of the added value of school? In a study of 4000 pairs of 12-year-old twins in the UK, we measured achievement with year-long teacher assessments as well as tests. Raw achievement shows moderate heritability (about 50%) and modest shared environmental influences (25%). Unexpectedly, we show that for indices of the added value of school, genetic influences remain moderate (around 50%), and the shared (school) environment is less important (about 12%). The pervasiveness of genetic influence in how and how much children learn is compatible with an active view of learning in which children create their own educational experiences in part on the basis of their genetic propensities
Soil Contamination Interpretation by the Use of Monitoring Data Analysis
The presented study deals with the interpretation of soil quality monitoring data using hierarchical cluster analysis (HCA) and principal components analysis (PCA). Both statistical methods contributed to the correct data classification and projection of the surface (0â20Â cm) and subsurface (20â40Â cm) soil layers of 36 sampling sites in the region of Burgas, Bulgaria. Clustering of the variables led to formation of four significant clusters corresponding to possible sources defining the soil quality like agricultural activity, industrial impact, fertilizing, etc. Two major clusters were found to explain the sampling site locations according to soil compositionâone cluster for coastal and mountain sites and anotherâfor typical rural and industrial sites. Analogous results were obtained by the use of PCA. The advantage of the latter was the opportunity to offer more quantitative interpretation of the role of identified soil quality sources by the level of explained total variance. The score plots and the dendrogram of the sampling sites indicated a relative spatial homogeneity according to geographical location and soil layer depth. The high-risk areas and pollution profiles were detected and visualized using surface maps based on Kriging algorithm
Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector
The inclusive and dijet production cross-sections have been measured for jets
containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass
energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The
measurements use data corresponding to an integrated luminosity of 34 pb^-1.
The b-jets are identified using either a lifetime-based method, where secondary
decay vertices of b-hadrons in jets are reconstructed using information from
the tracking detectors, or a muon-based method where the presence of a muon is
used to identify semileptonic decays of b-hadrons inside jets. The inclusive
b-jet cross-section is measured as a function of transverse momentum in the
range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet
cross-section is measured as a function of the dijet invariant mass in the
range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets
and the angular variable chi in two dijet mass regions. The results are
compared with next-to-leading-order QCD predictions. Good agreement is observed
between the measured cross-sections and the predictions obtained using POWHEG +
Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet
cross-section. However, it does not reproduce the measured inclusive
cross-section well, particularly for central b-jets with large transverse
momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final
version published in European Physical Journal
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