25,986 research outputs found
The solar eclipse: a natural meteorological experiment
A solar eclipse provides a well-characterised reduction in solar radiation, of calculable amount and duration. This captivating natural astronomical phenomenon is ideally suited to science outreach activities, but the predictability of the change in solar radiation also provides unusual conditions for assessing the atmospheric response to a known stimulus. Modern automatic observing networks used for weather forecasting and atmospheric research have dense spatial coverage, so the quantitative meteorological responses to an eclipse can now be evaluated with excellent space and time resolution. Numerical models representing the atmosphere at high spatial resolution can also be used to predict eclipse related changes and interpret the observations. Combining the models with measurements yields the elements of a controlled atmospheric experiment on a regional scale (10 to 1000 km), which is almost impossible to achieve by other means. This modern approach to “eclipse meteorology” as identified here can ultimately improve weather-prediction models and be used to plan for transient reductions in renewable electricity generation. During the 20th March 2015 eclipse, UK electrical energy demand increased by about 3 GWh (11 TJ) or about 4%, alongside reductions in the wind and photovoltaic electrical energy generation of 1.5 GWh (5.5TJ)
Effects of age of acquisition and semantic transparency on reading characters in Chinese dyslexia
This study examined the effects of the age of acquisition (AOA) and semantic transparency on the reading aloud ability of a Chinese dyslexic individual, TWT, who relied on the semantic pathway to name characters. Both AOA and semantic transparency significantly predicted naming accuracy and distinguished the occurrence of correct responses and semantic errors from other errors. A post hoc analysis of subsets of items orthogonally varied in the AOA and semantic transparency revealed an interaction between the two variables. These findings converge on reports of AOA and semantic effects on deep dyslexic individuals reading alphabetic scripts. The case of TWT, together with recent results of another Chinese dyslexic individual who reads via the nonsemantic route and exhibits the effects of AOA and phonological consistency, supports the arbitrary mapping hypothesis, which states that the AOA effect resides in the connection between two levels of representation. © Cambridge University Press 2010.published_or_final_versio
Identification of a serum biomarker panel for the differential diagnosis of cholangiocarcinoma and primary sclerosing cholagnitis
The non-invasive differentiation of malignant and benign biliary disease is a clinical challenge. Carbohydrate antigen 19-9 (CA19-9), leucine-rich α2-glycoprotein (LRG1), interleukin 6 (IL6), pyruvate kinase M2 (PKM2), cytokeratin 19 fragment (CYFRA21.1) and mucin 5AC (MUC5AC) have reported utility for differentiating cholangiocarcinoma (CCA) from benign biliary disease. Herein, serum levels of these markers were tested in 66 cases of CCA and 62 cases of primary sclerosing cholangitis (PSC) and compared with markers of liver function and inflammation. Markers panels were assessed for their ability to discriminate malignant and benign disease. Several of the markers were also assessed in pre-diagnosis biliary tract cancer (BTC) samples with performances evaluated at different times prior to diagnosis. We show that LRG1 and IL6 were unable to accurately distinguish CCA from PSC, whereas CA19-9, PKM2, CYFRA21.1 and MUC5AC were significantly elevated in malignancy. Area under the receiver operating characteristic curves for these individual markers ranged from 0.73–0.84, with the best single marker (PKM2) providing 61% sensitivity at 90% specificity. A panel combining PKM2, CYFRA21.1 and MUC5AC gave 76% sensitivity at 90% specificity, which increased to 82% sensitivity by adding gamma-glutamyltransferase (GGT). In the pre-diagnosis setting, LRG1, IL6 and PKM2 were poor predictors of BTC, whilst CA19-9 and C-reactive protein were elevated up to 2 years before diagnosis. In conclusion, LRG1, IL6 and PKM2 were not useful for early detection of BTC, whilst a model combining PKM2, CYFRA21.1, MUC5AC and GGT was beneficial in differentiating malignant from benign biliary disease, warranting validation in a prospective trial
Subfractions of enamel matrix derivative differentially influence cytokine secretion from human oral fibroblasts.
Enamel matrix derivative is used to promote periodontal regeneration during the corrective phase of the treatment of periodontal defects. Our main goal was to analyze the bioactivity of different molecular weight fractions of enamel matrix derivative. Enamel matrix derivative, a complex mixture of proteins, was separated into 13 fractions using size-exclusion chromatography and characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and liquid chromatography-electrospray ionization-tandem mass spectrometry. Human periodontal ligament fibroblasts were treated with either enamel matrix derivative or the different fractions. Proliferation and cytokine secretion to the cell culture medium were measured and compared to untreated cells. The liquid chromatography-electrospray ionization-tandem mass spectrometry analyses revealed that the most abundant peptides were amelogenin and leucine-rich amelogenin peptide related. The fractions containing proteins above 20 kDa induced an increase in vascular endothelial growth factor and interleukin-6 secretion, whereas lower molecular weight fractions enhanced proliferation and secretion of interleukin-8 and monocyte chemoattractant protein-1 and reduced interleukin-4 release. The various molecular components in the enamel matrix derivative formulation might contribute to reported effects on tissue regeneration through their influence on vascularization, the immune response, and chemotaxis
Decoupling heavy sparticles in Effective SUSY scenarios: Unification, Higgs masses and tachyon bounds
Using two-loop renormalization group equations implementing the decoupling of
heavy scalars, Effective SUSY scenarios are studied in the limit in which there
is a single low energy Higgs field. Gauge coupling unification is shown to hold
with similar or better precision than in standard MSSM scenarios. b-tau
unification is examined, and Higgs masses are computed using the effective
potential, including two-loop contributions from scalars. A 125 GeV Higgs is
compatible with stops/sbottoms at around 300 GeV with non-universal boundary
conditions at the scale of the heavy sparticles if some of the trilinear
couplings at this scale take values of the order of 1-2 TeV; if more
constrained boundary conditions inspired by msugra or gauge mediation are set
at a higher scale, heavier colored sparticles are required in general. Finally,
since the decoupled RG flow for third-generation scalar masses departs very
significantly from the MSSM DR-bar one, tachyon bounds for light scalars are
revisited and shown to be relaxed by up to a TeV or more.Comment: 35 pages, 17 figures. v2: Updated some scans, allowing for changes in
sign of some parameters, minor improvements. v3: Typos corrected in formulae
in the appendices, added some clarifying remarks about flavor mixing being
ignore
Ecological equivalence: a realistic assumption for niche theory as a testable alternative to neutral theory
Hubbell's 2001 neutral theory unifies biodiversity and biogeography by modelling steady-state distributions of species richness and abundances across spatio-temporal scales. Accurate predictions have issued from its core premise that all species have identical vital rates. Yet no ecologist believes that species are identical in reality. Here I explain this paradox in terms of the ecological equivalence that species must achieve at their coexistence equilibrium, defined by zero net fitness for all regardless of intrinsic differences between them. I show that the distinction of realised from intrinsic vital rates is crucial to evaluating community resilience. An analysis of competitive interactions reveals how zero-sum patterns of abundance emerge for species with contrasting life-history traits as for identical species. I develop a stochastic model to simulate community assembly from a random drift of invasions sustaining the dynamics of recruitment following deaths and extinctions. Species are allocated identical intrinsic vital rates for neutral dynamics, or random intrinsic vital rates and competitive abilities for niche dynamics either on a continuous scale or between dominant-fugitive extremes. Resulting communities have steady-state distributions of the same type for more or less extremely differentiated species as for identical species. All produce negatively skewed log-normal distributions of species abundance, zero-sum relationships of total abundance to area, and Arrhenius relationships of species to area. Intrinsically identical species nevertheless support fewer total individuals, because their densities impact as strongly on each other as on themselves. Truly neutral communities have measurably lower abundance/area and higher species/abundance ratios. Neutral scenarios can be parameterized as null hypotheses for testing competitive release, which is a sure signal of niche dynamics. Ignoring the true strength of interactions between and within species risks a substantial misrepresentation of community resilience to habitat los
Consensus on the use of the fixed combination calcipotriol/betamethasone dipropionate in the treatment of plaque psoriasis.
Calcipotriol, a vitamin D analogue, and betamethasone dipropionate, a high potency corticosteroid, are complementary agents for the topical treatment of psoriasis vulgaris. Robust evidence on the efficacy and safety of their fixed combination has been provided by randomized, double-blind, controlled clinical trials involving more than 7000 patients with the ointment formulation in psoriasis of the body and more than 4000 patients with the gel formulation in scalp psoriasis. These trials have shown that the fixed combination ointment is more effective and better tolerated, not only than placebo, but also than calcipotriol and tacalcitol monotherapies. In addition, it has proved, in most instances, to be more effective than betamethasone and at least as well tolerated. The same applies to the gel for scalp and body psoriasis. Safety studies have excluded that repeated courses of treatment with the fixed combination for up to one year produce systemic effects. Studies have also shown that the fixed combination treatment improves quality of life to a significantly greater extent than calcipotriol, with the once daily regimen most appreciated by patients, in both active disease and recurrency. Because of the extensive evidence, American and European guidelines recommend the calcipotriol/betamethasone dipropionate fixed combination a
Three-dimensional reconstruction and visualization of the cerebral cortex in primates
We present a prototype interactive application for the direct analysis in three dimensions of the cerebral cortex in primates. The paper provides an overview of the current prototype system and presents the techniques used for reconstructing the cortex shape from data derived from histological sections as well as for rendering it at interactive rates. Results are evaluated by discussing the analysis of the right hemisphere of the brain of a macaque monkey used for neuroanatomical tract-tracing experiments.147-15
Expression of steroid receptor coactivator 3 in ovarian epithelial cancer is a poor prognostic factor and a marker for platinum resistance
BACKGROUND: Steroid receptor coactivator 3 (SRC3) is an important coactivator of a number of transcription factors and is associated with a poor outcome in numerous tumours. Steroid receptor coactivator 3 is amplified in 25% of epithelial ovarian cancers (EOCs) and its expression is higher in EOCs compared with non-malignant tissue. No data is currently available with regard to the expression of SRC-3 in EOC and its influence on outcome or the efficacy of treatment. METHODS: Immunohistochemistry was performed for SRC3, oestrogen receptor-α, HER2, PAX2 and PAR6, and protein expression was quantified using automated quantitative immunofluorescence (AQUA) in 471 EOCs treated between 1991 and 2006 with cytoreductive surgery followed by first-line treatment platinum-based therapy, with or without a taxane. RESULTS: Steroid receptor coactivator 3 expression was significantly associated with advanced stage and was an independent prognostic marker. High expression of SRC3 identified patients who have a significantly poorer survival with single-agent carboplatin chemotherapy, while with carboplatin/paclitaxel treatment such a difference was not seen. CONCLUSION: Steroid receptor coactivator 3 is a poor prognostic factor in EOCs and appears to identify a population of patients who would benefit from the addition of taxanes to their chemotherapy regimen, due to intrinsic resistance to platinum therapy
- …
