309 research outputs found

    Resolved images of the protoplanetary disk around HD 100546 with ALMA

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    The disk around the Herbig Ae/Be star HD 100546 has been extensively studied and it is one of the systems for which there are observational indications of ongoing and/or recent planet formation. However, up until now no resolved image of the millimeter dust emission or the gas has been published. We present the first resolved images of the disk around HD 100546 obtained in Band 7 with the ALMA observatory. The CO (3-2) image reveals a gas disk that extends out to 350 au radius at the 3-sigma level. Surprisingly, the 870um dust continuum emission is compact (radius <60 au) and asymmetric. The dust emission is well matched by a truncated disk with outer radius of \approx50 au. The lack of millimeter-sized particles outside the 60 au is consistent with radial drift of particles of this size. The protoplanet candidate, identified in previous high-contrast NACO/VLT L' observations, could be related to the sharp outer edge of the millimeter-sized particles. Future higher angular resolution ALMA observations are needed to determine the detailed properties of the millimeter emission and the gas kinematics in the inner region (<2arcsec). Such observations could also reveal the presence of a planet through the detection of circumplanetary disk material.Comment: 6 pages, 4 figures. Accepted in ApJ

    Socio-demographic and economic correlates of climate change coping and adaptation strategies : a study on the farmer communities in Barisal District, Bangladesh

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    The major objective of the study is to apply Conservation of Resource (COR) theory for examining the influence of farmers’ socio-demographic and economic correlates upon their adoption of agricultural, economic and emotion-focused coping and adaptation strategies of climate change. An interview schedule developed from the COR theory was utilized for data collection. Using multistage cluster sampling technique, a total of 384 farmers were chosen from Agailjhara Upazila of Barisal District and interviewed through a predesigned structured questionnaire. For triangulation of the quantitative findings, the study employed case study technique to collect qualitative data from the respondents. The findings of the study demonstrate that the most common emotion-focused, agricultural and economic coping and adaptation strategies of climate change were social support seeking (79.69%), planting trees (71.35%), homestead gardening (52.08%), hydroponic farming/floating garden (46.88%), duck rearing (30.73%), saving (20.83%), self-insurance (18.75%), etc. Bivariate results indicate that age, ownership of land, income and ownership of television or mobile phone were found significantly correlated with the three variables, including economic, agricultural and emotion-focused coping and adaptation strategies of COR theory. Again, access to microcredit has relationship with economic and agricultural adaptation strategies. Furthermore, education has significant relationship with agricultural adaptation strategies. The study suggests that continuous researches by policy makers, researchers, GOs and NGOs are very essential to exploring and enhancing farmers’ coping and adaptation strategies which may relegate the adverse impacts and vulnerabilities of climate change in the study area

    How far does a big push really push?

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    BRAC implemented the Challenging the Frontiers of Poverty Reduction: Specially Targeted Ultra-Poor (CFPR) program in 2002 to mitigate ultra-poverty in the poorest districts of Bangladesh, providing multifaceted support in the form of asset-transfer, food-stipends, education, healthcare and social support for two years. Utilizing a four-round panel data spanning 9 years and combining regression and propensity score weighting, we evaluate CFPR’s short and long term impact on income, employment, social status, food security and asset ownership. While remarkable effects of CFPR are evident in short and medium-term (up to 6 years since baseline), longer-term effects (up to 9 years) are smaller. The latter happens due to a variety of factors including faster catch-up by the control group, due partly to various new interventions by state and non-state sectors. We see a shift from begging, working as maids and day-laboring to entrepreneurial activities in the short and medium term, but many CFPR households revert back to their baseline employment by 2011. Analyses of the heterogeneity of effects across baseline employment and gender of the household-head reveal greater long-term impact on per-capita income for entrepreneurs and greater short-term impact for female-headed households. Overall, despite the deceleration of the effects in the long run, the program was able to successfully bring its participants out of ultra-poverty and had important demonstration effects

    Genetic Targeting of ERK1 Suggests a Predominant Role for ERK2 in Murine Pain Models

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    The extracellular signal-regulated kinase (ERK) isoforms, ERK1 and ERK2, are believed to be key signaling molecules in nociception and nociceptive sensitization. Studies utilizing inhibitors targeting the shared ERK1/2 upstream activator, mitogen-activated protein kinase kinase (MEK), and transgenic mice expressing a dominant negative form of MEK have established the importance of ERK1/2 signaling. However, these techniques do not discriminate between ERK1 and ERK2. To dissect the function of each isoform in pain, we utilized mice with a targeted genetic deletion of ERK1 (ERK1 KO) to test the hypothesis that ERK1 is required for behavioral sensitization in rodent pain models. Despite activation (phosphorylation) of ERK1 following acute noxious stimulation and in models of chronic pain, we found that ERK1 was not required for formalin-induced spontaneous behaviors, complete Freund’s adjuvant-induced heat and mechanical hypersensitivity, and spared nerve injury-induced mechanical hypersensitivity. However, ERK1 deletion did delay formalin-induced long-term heat hypersensitivity, without affecting formalin-induced mechanical hypersensitivity, suggesting that ERK1 partially shapes long-term responses to formalin. Interestingly, ERK1 deletion resulted in elevated basal ERK2 phosphorylation. However, this did not appear to influence nociceptive processing, since inflammation-induced ERK2 phosphorylation and pERK1/2 immunoreactivity in spinal cord were not elevated in ERK1 KO mice. Additionally, systemic MEK inhibition with SL327 attenuated formalin-induced spontaneous behaviors similarly in WT and ERK1 KO mice, indicating that unrelated signaling pathways do not functionally compensate for the loss of ERK1. Taken together, these results suggest that ERK1 plays a limited role in nociceptive sensitization and supports a predominant role for ERK2 in these processes

    The Production and Utilization of GDP-glucose in the Biosynthesis of Trehalose 6-Phosphate by Streptomyces venezuelae

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    Trehalose-6-phosphate synthase OtsA from streptomycetes is unusual in that it uses GDP-glucose as the donor substrate rather than the more commonly used UDP-glucose. We now confirm that OtsA from Streptomyces venezuelae has such a preference for GDP-glucose and can utilize ADP-glucose to some extent too. A crystal structure of the enzyme shows that it shares twin Rossmann-like domains with the UDP-glucose-specific OtsA from Escherichia coli. However, it is structurally more similar to Streptomyces hygroscopicus VldE, a GDP-valienol-dependent pseudoglycosyltransferase enzyme. Comparison of the donor binding sites reveals that the amino acids associated with the binding of diphosphoribose are almost all identical in these three enzymes. By contrast, the amino acids associated with binding guanine in VldE (Asn, Thr, and Val) are similar in S. venezuelae OtsA (Asp, Ser, and Phe, respectively) but not conserved in E. coli OtsA (His, Leu, and Asp, respectively), providing a rationale for the purine base specificity of S. venezuelae OtsA. To establish which donor is used in vivo, we generated an otsA null mutant in S. venezuelae. The mutant had a cell density-dependent growth phenotype and accumulated galactose 1-phosphate, glucose 1-phosphate, and GDP-glucose when grown on galactose. To determine how the GDP-glucose is generated, we characterized three candidate GDP-glucose pyrophosphorylases. SVEN_3027 is a UDP-glucose pyrophosphorylase, SVEN_ 3972 is an unusual ITP-mannose pyrophosphorylase, and SVEN_2781 is a pyrophosphorylase that is capable of generating GDP-glucose as well as GDP-mannose. We have therefore established how S. venezuelae can make and utilize GDP-glucose in the biosynthesis of trehalose 6-phosphate

    Modulation of Angiogenic and Inflammatory Response in Glioblastoma by Hypoxia

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    Glioblastoma are rapidly proliferating brain tumors in which hypoxia is readily recognizable, as indicated by focal or extensive necrosis and vascular proliferation, two independent diagnostic criteria for glioblastoma. Gene expression profiling of glioblastoma revealed a gene expression signature associated with hypoxia-regulated genes. The correlated gene set emerging from unsupervised analysis comprised known hypoxia-inducible genes involved in angiogenesis and inflammation such as VEGF and BIRC3, respectively. The relationship between hypoxia-modulated angiogenic genes and inflammatory genes was associated with outcome in our cohort of glioblastoma patients treated within prospective clinical trials of combined chemoradiotherapy. The hypoxia regulation of several new genes comprised in this cluster including ZNF395, TNFAIP3, and TREM1 was experimentally confirmed in glioma cell lines and primary monocytes exposed to hypoxia in vitro. Interestingly, the cluster seems to characterize differential response of tumor cells, stromal cells and the macrophage/microglia compartment to hypoxic conditions. Most genes classically associated with the inflammatory compartment are part of the NF-kappaB signaling pathway including TNFAIP3 and BIRC3 that have been shown to be involved in resistance to chemotherapy

    An occupational therapy intervention for residents with stroke related disabilities in UK care homes (OTCH): cluster randomised controlled trial

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    Objective To evaluate the clinical efficacy of an established programme of occupational therapy in maintaining functional activity and reducing further health risks from inactivity in care home residents living with stroke sequelae. Design Pragmatic, parallel group, cluster randomised controlled trial. Setting 228 care homes (>10 beds each), both with and without the provision of nursing care, local to 11 trial administrative centres across the United Kingdom. Participants 1042 care home residents with a history of stroke or transient ischaemic attack, including those with language and cognitive impairments, not receiving end of life care. 114 homes (n=568 residents, 64% from homes providing nursing care) were allocated to the intervention arm and 114 homes (n=474 residents, 65% from homes providing nursing care) to standard care (control arm). Participating care homes were randomised between May 2010 and March 2012. Intervention Targeted three month programme of occupational therapy, delivered by qualified occupational therapists and assistants, involving patient centred goal setting, education of care home staff, and adaptations to the environment. Main outcome measures Primary outcome at the participant level: scores on the Barthel index of activities of daily living at three months post-randomisation. Secondary outcome measures at the participant level: Barthel index scores at six and 12 months post-randomisation, and scores on the Rivermead mobility index, geriatric depression scale-15, and EuroQol EQ-5D-3L questionnaire, at all time points. Results 64% of the participants were women and 93% were white, with a mean age of 82.9 years. Baseline characteristics were similar between groups for all measures, personal characteristics, and diagnostic tests. Overall, 2538 occupational therapy visits were made to 498 participants in the intervention arm (mean 5.1 visits per participant). No adverse events attributable to the intervention were recorded. 162 (11%) died before the primary outcome time point, and 313 (30%) died over the 12 months of the trial. The primary outcome measure did not differ significantly between the treatment arms. The adjusted mean difference in Barthel index score at three months was 0.19 points higher in the intervention arm (95% confidence interval −0.33 to 0.70, P=0.48). Secondary outcome measures also showed no significant differences at all time points. Conclusions This large phase III study provided no evidence of benefit for the provision of a routine occupational therapy service, including staff training, for care home residents living with stroke related disabilities. The established three month individualised course of occupational therapy targeting stroke related disabilities did not have an impact on measures of functional activity, mobility, mood, or health related quality of life, at all observational time points. Providing and targeting ameliorative care in this clinically complex population requires alternative strategies

    Molecular dynamics symulation of hydrogen diffusion in palladium

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    In the present work, the diffusion of hydrogen atoms in the crystal lattice of palladium was investigated using the molecular dynamics. The diffusion coefficients, activation energies and preexponential factors were determined for structures with different hydrogen concentration. It is determined that the diffusion coefficients decrease and the activation energy of diffusion grows with increasing concentrations of hydrogen
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