229 research outputs found
Ecological correlations of nocturnal bird assemblages in Malaysian Borneo
Malaysian Borneo supports a rich assemblage of five nightbird families, comprising 13 species of owl, six of frogmouth and four of nightjar. Many nightbirds are dependent on forest habitats, but their ecology remains poorly known. Our study examined the relationships between nocturnal bird species richness and environmental variables based on citizen science dataâbird records collected in Malaysian Borneo from 2000â2012. The environmental variables were altitude, distance to waterbodies, distance to human settlements, and land cover type, generated from geographic information system (GIS) data. For 18 species found in three land cover types, the Shannon-Wiener H diversity value was highest in primary forest, followed by fallow agricultural land and secondary forest. Except for the distance to human settlements, our generalised linear model (GLM) showed significant positive relationships between species richness and distance to waterbodies, as well as altitude. However, the land cover type of each site did not significantly influence species richness. Our findings suggest that primary forests remain a relatively important habitat for nocturnal bird communities in Borneo, but it is likely that some species may be able to adapt to and exploit secondary habitats, although the extent of this warrants future study
Apolipoprotein E and Alzheimerâs disease: The influence of apolipoprotein E on amyloid- and other amyloidogenic proteins
Using mixed objects in the training of object-based image classifications
Image classification for thematic mapping is a very common application in remote sensing, which is sometimes realized through object-based image analysis. In these analyses, it is common for some of the objects to be mixed in their class composition and thus violate the commonly made assumption of object purity that is implicit in a conventional object-based image analysis. Mixed objects can be a problem throughout a classification analysis, but are particularly challenging in the training stage as they can result in degraded training statistics and act to reduce mapping accuracy. In this paper the potential of using mixed objects in training object-based image classifications is evaluated. Remotely sensed data were submitted to a series of segmentation analyses from which a range of under- to over-segmented outputs were intentionally produced. Training objects were then selected from the segmentation outputs, resulting in training data sets that varied in terms of size (i.e. number of objects) and proportion of mixed objects. These training data sets were then used with an artificial neural network and a generalized linear model, which can accommodate objects of mixed composition, to produce a series of land cover maps. The use of training statistics estimated based on both pure and mixed objects often increased classification accuracy by around 25% when compared with accuracies obtained from the use of only pure objects in training. So rather than the mixed objects being a problem, they can be an asset in classification and facilitate land cover mapping from remote sensing. It is, therefore, desirable to recognize the nature of the objects and possibly accommodate mixed objects directly in training. The results obtained here may also have implications for the common practice of seeking an optimal segmentation output, and also act to challenge the widespread view that object-based classification is superior to pixel-based classification
An evaluation of the lighting environment in the public space of shopping centres
Interior lighting quality influences people's visual comfort and satisfaction with a space. Based on a field study about the effects of lighting environments on occupancies in eight shopping malls with three different latitudes and a wide range of size from 30,000 to 210,000Â m2 all over China, this study investigates the differences in subjective evaluations, the correlations between the lighting environments of public spaces and people's evaluations, and the regressions of scene mean luminance. A questionnaire survey and HDR-image techniques have been used to gather subjective feedback and collect physical lighting data. The results show that the subjective evaluations among different groups (gender, age, education background, and duration of stay in the shopping malls) are similar. The existence of daylighting plays an important role in subjective satisfaction, but not crucial enough to their brightness perception. The mean luminance values of these scenes are closely correlated to the diversity of the subjective evaluations. For shopping centres, the optimal Lmean value is 1000Â cd/m2 for a mixed daylighting and artificial lighting environment, and 75Â cd/m2 as the recommended Lmean value for an artificial lighting environment
Pten (phosphatase and tensin homologue gene) haploinsufficiency promotes insulin hypersensitivity
AIMS/HYPOTHESIS: Insulin controls glucose metabolism via multiple signalling pathways, including the phosphatidylinositol 3-kinase (PI3K) pathway in muscle and adipose tissue. The protein/lipid phosphatase Pten (phosphatase and tensin homologue deleted on chromosome 10) attenuates PI3K signalling by dephosphorylating the phosphatidylinositol 3,4,5-trisphosphate generated by PI3K. The current study was aimed at investigating the effect of haploinsufficiency for Pten on insulin-stimulated glucose uptake. MATERIALS AND METHODS: Insulin sensitivity in Pten heterozygous (Pten(+/â)) mice was investigated in i.p. insulin challenge and glucose tolerance tests. Glucose uptake was monitored in vitro in primary cultures of myocytes from Pten(+/â) mice, and in vivo by positron emission tomography. The phosphorylation status of protein kinase B (PKB/Akt), a downstream signalling protein in the PI3K pathway, and glycogen synthase kinase 3ÎČ (GSK3ÎČ), a substrate of PKB/Akt, was determined by western immunoblotting. RESULTS: Following i.p. insulin challenge, blood glucose levels in Pten(+/â) mice remained depressed for up to 120Â min, whereas glucose levels in wild-type mice began to recover after approximately 30Â min. After glucose challenge, blood glucose returned to normal about twice as rapidly in Pten(+/â) mice. Enhanced glucose uptake was observed both in Pten(+/â) myocytes and in skeletal muscle of Pten(+/â) mice by PET. PKB and GSK3ÎČ phosphorylation was enhanced and prolonged in Pten(+/â) myocytes. CONCLUSIONS/INTERPRETATION: Pten is a key negative regulator of insulin-stimulated glucose uptake in vitro and in vivo. The partial reduction of Pten due to Pten haploinsufficiency is enough to elicit enhanced insulin sensitivity and glucose tolerance in Pten(+/â) mice
Germline breast cancer susceptibility genes, tumor characteristics, and survival.
BACKGROUND: Mutations in certain genes are known to increase breast cancer risk. We study the relevance of rare protein-truncating variants (PTVs) that may result in loss-of-function in breast cancer susceptibility genes on tumor characteristics and survival in 8852 breast cancer patients of Asian descent. METHODS: Gene panel sequencing was performed for 34 known or suspected breast cancer predisposition genes, of which nine genes (ATM, BRCA1, BRCA2, CHEK2, PALB2, BARD1, RAD51C, RAD51D, and TP53) were associated with breast cancer risk. Associations between PTV carriership in one or more genes and tumor characteristics were examined using multinomial logistic regression. Ten-year overall survival was estimated using Cox regression models in 6477 breast cancer patients after excluding older patients (â„75years) and stage 0 and IV disease. RESULTS: PTV9genes carriership (n = 690) was significantly associated (p < 0.001) with more aggressive tumor characteristics including high grade (poorly vs well-differentiated, odds ratio [95% confidence interval] 3.48 [2.35-5.17], moderately vs well-differentiated 2.33 [1.56-3.49]), as well as luminal B [HER-] and triple-negative subtypes (vs luminal A 2.15 [1.58-2.92] and 2.85 [2.17-3.73], respectively), adjusted for age at diagnosis, study, and ethnicity. Associations with grade and luminal B [HER2-] subtype remained significant after excluding BRCA1/2 carriers. PTV25genes carriership (n = 289, excluding carriers of the nine genes associated with breast cancer) was not associated with tumor characteristics. However, PTV25genes carriership, but not PTV9genes carriership, was suggested to be associated with worse 10-year overall survival (hazard ratio [CI] 1.63 [1.16-2.28]). CONCLUSIONS: PTV9genes carriership is associated with more aggressive tumors. Variants in other genes might be associated with the survival of breast cancer patients. The finding that PTV carriership is not just associated with higher breast cancer risk, but also more severe and fatal forms of the disease, suggests that genetic testing has the potential to provide additional health information and help healthy individuals make screening decisions
Expected Performance of the ATLAS Experiment - Detector, Trigger and Physics
A detailed study is presented of the expected performance of the ATLAS
detector. The reconstruction of tracks, leptons, photons, missing energy and
jets is investigated, together with the performance of b-tagging and the
trigger. The physics potential for a variety of interesting physics processes,
within the Standard Model and beyond, is examined. The study comprises a series
of notes based on simulations of the detector and physics processes, with
particular emphasis given to the data expected from the first years of
operation of the LHC at CERN
Novel Thermoplastic Fibre-Metal Laminates Manufactured by Vacuum Resin Infusion: The Effect of Surface Treatments on Interfacial Bonding
The manufacturing process of a new generation of thermoplastic fibre-metal laminates (TP-FMLs) was investigated. A vacuum assisted resin infusion method was used to produce the hybrid laminates. The effect of various chemical and physical treatments on the surface morphology of the aluminium (Al) alloy sheets and on the bond strength at the metal-composite interface was examined. The wettability, topography and chemical composition of the treated Al alloy sheets were studied by employing contact-angle goniometry, coherence scanning interferometry, profilometry and X-ray photoelectron spectroscopy. The results showed that the applied treatments on the Al alloy sheet changed the surface morphology and surface energy in a different degree, which in turn effectively enhanced the interfacial bond strength between the constituents. In addition, the flexural, interlaminar shear strength and interlaminar fracture toughness of the manufactured TP-FMLs with the optimum metal surface treatment were evaluated. The experimental results of the TP-FMLs were compared to an equivalent thermoplastic composite. The composite-metal interface and the fracture surface characteristics were examined under scanning electron microscopy. In-situ polymerisation was found to play a key role in bonding the treated Al alloy with the composite layer during manufacturing
Systematic Review of Potential Health Risks Posed by Pharmaceutical, Occupational and Consumer Exposures to Metallic and Nanoscale Aluminum, Aluminum Oxides, Aluminum Hydroxide and Its Soluble Salts
Aluminum (Al) is a ubiquitous substance encountered both naturally (as the third most abundant element) and intentionally (used in water, foods, pharmaceuticals, and vaccines); it is also present in ambient and occupational airborne particulates. Existing data underscore the importance of Al physical and chemical forms in relation to its uptake, accumulation, and systemic bioavailability. The present review represents a systematic examination of the peer-reviewed literature on the adverse health effects of Al materials published since a previous critical evaluation compiled by Krewski et al. (2007).
Challenges encountered in carrying out the present review reflected the experimental use of different physical and chemical Al forms, different routes of administration, and different target organs in relation to the magnitude, frequency, and duration of exposure. Wide variations in diet can result in Al intakes that are often higher than the World Health Organization provisional tolerable weekly intake (PTWI), which is based on studies with Al citrate. Comparing daily dietary Al exposures on the basis of âtotal Alâassumes that gastrointestinal bioavailability for all dietary Al forms is equivalent to that for Al citrate, an approach that requires validation. Current occupational exposure limits (OELs) for identical Al substances vary as much as 15-fold.
The toxicity of different Al forms depends in large measure on their physical behavior and relative solubility in water. The toxicity of soluble Al forms depends upon the delivered dose of Al+ 3 to target tissues. Trivalent Al reacts with water to produce bidentate superoxide coordination spheres [Al(O2)(H2O4)+ 2 and Al(H2O)6 + 3] that after complexation with O2âąâ, generate Al superoxides [Al(O2âą)](H2O5)]+ 2. Semireduced AlO2âą radicals deplete mitochondrial Fe and promote generation of H2O2, O2 âą â and OHâą. Thus, it is the Al+ 3-induced formation of oxygen radicals that accounts for the oxidative damage that leads to intrinsic apoptosis. In contrast, the toxicity of the insoluble Al oxides depends primarily on their behavior as particulates.
Aluminum has been held responsible for human morbidity and mortality, but there is no consistent and convincing evidence to associate the Al found in food and drinking water at the doses and chemical forms presently consumed by people living in North America and Western Europe with increased risk for Alzheimer\u27s disease (AD). Neither is there clear evidence to show use of Al-containing underarm antiperspirants or cosmetics increases the risk of AD or breast cancer. Metallic Al, its oxides, and common Al salts have not been shown to be either genotoxic or carcinogenic. Aluminum exposures during neonatal and pediatric parenteral nutrition (PN) can impair bone mineralization and delay neurological development. Adverse effects to vaccines with Al adjuvants have occurred; however, recent controlled trials found that the immunologic response to certain vaccines with Al adjuvants was no greater, and in some cases less than, that after identical vaccination without Al adjuvants.
The scientific literature on the adverse health effects of Al is extensive. Health risk assessments for Al must take into account individual co-factors (e.g., age, renal function, diet, gastric pH). Conclusions from the current review point to the need for refinement of the PTWI, reduction of Al contamination in PN solutions, justification for routine addition of Al to vaccines, and harmonization of OELs for Al substances
The performance of the jet trigger for the ATLAS detector during 2011 data taking
The performance of the jet trigger for the ATLAS detector at the LHC during the 2011 data taking period is described. During 2011 the LHC provided protonâproton collisions with a centre-of-mass energy of 7 TeV and heavy ion collisions with a 2.76 TeV per nucleonânucleon collision energy. The ATLAS trigger is a three level system designed to reduce the rate of events from the 40 MHz nominal maximum bunch crossing rate to the approximate 400 Hz which can be written to offline storage. The ATLAS jet trigger is the primary means for the online selection of events containing jets. Events are accepted by the trigger if they contain one or more jets above some transverse energy threshold. During 2011 data taking the jet trigger was fully efficient for jets with transverse energy above 25 GeV for triggers seeded randomly at Level 1. For triggers which require a jet to be identified at each of the three trigger levels, full efficiency is reached for offline jets with transverse energy above 60 GeV. Jets reconstructed in the final trigger level and corresponding to offline jets with transverse energy greater than 60 GeV, are reconstructed with a resolution in transverse energy with respect to offline jets, of better than 4 % in the central region and better than 2.5 % in the forward direction
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