2,535 research outputs found

    Evidence for polarised boron in Co-B and Fe-B alloys

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    By exploiting the tunability of synchrotron radiation in measurements of spin-resolved photoemission it has proved possible to obtain information on the polarisation of the valence electrons of Co-B and Fe-B amorphous magnetic alloys, Both the spin-integrated and spin-resolved energy distribution curves show a marked dependence on photon energy indicating that the p states of boron hybridise with the d states of the transition metals giving rise to mixed states in the binding energy range 1 to 5 eV, The observed polarisation and spin-resolved densities of states imply that in the above restricted energy range there is a net negative polarisation of the boron states

    Understanding the business consequences of ERP use

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    ERP systems are large integrated packaged software systems used by thousands of major organizations around the world. Yet outcomes from ERP use can be very different, and there is still not an adequate understanding of how and why organizations have such varying outcomes. Using an interpretive case study approach the post implementation periods in four manufacturing companies were examined retrospectively as processes within context over time. Structuration theory was used in the analysis of the cases to identify six themes that explain ’how’ and three contexts that explain ’why’ that form the components of an explanatory framework. The framework provides a foundation for future studies to understand and explain how and why organizations have or have not achieved business benefits from ERP systems

    Peripheries and praxis: the effect of rubric co-construction on student perceptions of their learning

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    The construction of assessment rubrics is often educator-centric as lecturers work in isolation to compose grading tools. While there is a pedagogical goal to construct instruments that align with learning outcomes and guide the assessment of students’ learning, students are often at the periphery of this process. In many higher education institutions, students are accustomed to receiving assessment feedback but they are not, typically, active participants in the feedback cycle. Increasingly, institutions are seeking evidence of greater student engagement in their tertiary learning experience. Accordingly, academics seek to innovate practice and enhance curricula by creating more opportunities for student involvement, thus creating a shared understanding of it and associated assessment tasks. Responding to a gap in rubric construction practice, this paper discusses an Office for Learning and Teaching Innovation and Development Grant research project where students moved from being rubric users to being central participants in collaborative design. Drawing on data collected from a team of rubric co-constructors from one Sydney university campus – first year students and an academic in a creative non-fiction writing subject – we set out to answer the following question: What effect does the co-construction and use of rubrics have on students’ perceptions of their learning

    Spin- and angle-resolved photoemission studies of the electronic structure of Si(110)"16x2" surfaces

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    The electronic structure of Si(110)"16 x 2" double-domain, single-domain and 1 x 1 surfaces have been investigated using spin- and angle-resolved photoemission at sample temperatures of 77 K and 300 K. Angle-resolved photoemission was conducted using horizontally- and vertically-polarised 60 eV and 80 eV photons. Band-dispersion maps revealed four surface states (S1S_1 to S4S_4) which were assigned to silicon dangling bonds on the basis of measured binding energies and photoemission intensity changes between horizontal and vertical light polarisations. Three surface states (S1S_1, S2S_2 and S4S_4), observed in the Si(110)"16 x 2" reconstruction, were assigned to Si adatoms and Si atoms present at the edges of the corrugated terrace structure. Only one of the four surface states, S3S_3, was observed in both the Si(110)"16 x 2" and 1 x 1 band maps and consequently attributed to the pervasive Si zigzag chains that are components of both the Si(110)"16 x 2" and 1 x 1 surfaces. A state in the bulk-band region was attributed to an in-plane bond. All data were consistent with the adatom-buckling model of the Si(110)"16 x 2" surface. Whilst room temperature measurements of PyP_y and PzP_z were statistically compatible with zero, PxP_x measurements of the enantiomorphic A-type and B-type Si(110)"16 x 2" surfaces gave small average polarisations of around 1.5\% that were opposite in sign. Further measurements at 77 K on A-type Si(110)"16 x 2" surface gave a smaller value of +0.3\%. An upper limit of 1%\sim1\% may thus be taken for the longitudinal polarisation.Comment: Main paper: 12 pages and 11 figures. Supplemental information: 5 pages and 2 figure

    UK guidelines for the management of soft tissue sarcomas

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    Soft tissue sarcomas (STS) are rare tumours arising in mesenchymal tissues, and can occur almost anywhere in the body. Their rarity, and the heterogeneity of subtype and location means that developing evidence-based guidelines is complicated by the limitations of the data available. However, this makes it more important that STS are managed by teams, expert in such cases, to ensure consistent and optimal treatment, as well as recruitment to clinical trials, and the ongoing accumulation of further data and knowledge. The development of appropriate guidance, by an experienced panel referring to the evidence available, is therefore a useful foundation on which to build progress in the field. These guidelines are an update of the previous version published in 2010 (Grimer et al. in Sarcoma 2010:506182, 2010). The original guidelines were drawn up following a consensus meeting of UK sarcoma specialists convened under the auspices of the British Sarcoma Group (BSG) and were intended to provide a framework for the multidisciplinary care of patients with soft tissue sarcomas. This current version has been updated and amended with reference to other European and US guidance. There are specific recommendations for the management of selected subtypes of disease including retroperitoneal and uterine sarcomas, as well as aggressive fibromatosis (desmoid tumours) and other borderline tumours commonly managed by sarcoma services. An important aim in sarcoma management is early diagnosis and prompt referral. In the UK, any patient with a suspected soft tissue sarcoma should be referred to one of the specialist regional soft tissues sarcoma services, to be managed by a specialist sarcoma multidisciplinary team. Once the diagnosis has been confirmed using appropriate imaging, plus a biopsy, the main modality of management is usually surgical excision performed by a specialist surgeon. In tumours at higher risk of recurrence or metastasis pre- or post-operative radiotherapy should be considered. Systemic anti-cancer therapy (SACT) may be utilized in some cases where the histological subtype is considered more sensitive to systemic treatment. Regular follow-up is recommended to assess local control, development of metastatic disease, and any late-effects of treatment. For local recurrence, and more rarely in selected cases of metastatic disease, surgical resection would be considered. Treatment for metastases may include radiotherapy, or systemic therapy guided by the sarcoma subtype. In some cases, symptom control and palliative care support alone will be appropriate

    Vitamin D deficiency is associated with tuberculosis disease in British children

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    Background53Basic science, epidemiological and interventional research supports a link between vitamin D and 54tuberculosis immunity, infection and disease. We evaluated the association between vitamin D 55levels and tuberculosis (TB) infection and disease in UK children recruited to the NIHR IGRA Kids 56Study (NIKS).57Methods58Children presenting between 2011-2014 were eligible if they had history of exposure to an adult 59case with sputum smear/culture-positive TB, or were referred and diagnosed with TB disease. 60Children were assessed at baseline and 6-8 weeks for immunological evidence of TB infection (IGRA 61and/or tuberculin skin test) and evidence of TB disease. Some centres routinely measured total 25-62hydroxy vitamin D levels.63Results64166 children were included. Median 25-hydroxy vitamin D levels were higher in uninfected children 65(45.5 nmol/l) compared to those with infection (36.2 nmol/l) and disease (20.0 nmol/l). The 66difference between TB infection and disease was statistically significant (p<0.001). By logistic 67regression, lower vitamin D levels were associated with TB disease among participants with 68infection/disease, with no evidence of confounding by age, sex, BCG status, ethnicity, non-contact 69referral, season or centre.70Conclusion71Children with TB disease had lower vitamin D levels than children with infection. Implications for 72prevention and treatment remain to be established

    Invest Ophthalmol Vis Sci

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    Purpose: To investigate the relationship of growth in drusen size with genetic susceptibility and adherence to the alternate Mediterranean diet. Methods: Participants in this analysis had complete ocular, genetic, and dietary data with mean follow-up time of 10.2 years in the Age-Related Eye Disease database. Maximal drusen size was graded on an ordinal scale and two-step progression was determined. A genetic risk score using variants associated with advanced AMD and derived from a stepwise regression model yielded 11 variants in 8 genes. Adherence to the alternate Mediterranean diet was assessed using a nine-component score based on intake of vegetables, fruits, legumes, whole cereals, fish, meat, nuts, alcohol, and monounsaturated-to-saturated fatty acids ratio. Multivariate Cox proportional hazards models were used. Results: Among 3023 eligible eyes, 19% had drusen growth. In the stepwise selection, common and rare risk alleles for CFH Y402H, CFH rs1410996, CFH R1210C, C3 R102G, C3 K155Q, and ARMS2/HTRA1, as well as VEGF-A, TIMP3, NPLOC4, and HSPH1 variants were significantly associated with 2-step progression in drusen size, and the C2 E318D protective allele conferred decreased risk, adjusting for other covariates. A higher genetic risk score conferred a higher risk (hazard ratio per 1-unit increase, 2.68; 95% confidence interval, 2.23–3.23; P < 0.001), and a medium/high adherence to alternate Mediterranean diet score (4–9) tended to lower risk (hazard ratio, 0.83; 95% confidence interval, 0.68–0.99; P = 0.049), adjusting for all covariates. Conclusions: Genetic susceptibility was independently related to drusen growth. A Mediterranean-style diet with healthful nutrient-rich foods (fruits, vegetables, legumes and fish), may reduce enlargement of drusen, the hallmark of AMD

    Phylogeography of eastern grey kangaroos, Macropus giganteus, suggests a mesic refugium in eastern Australia

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    Phylogeographic studies around the world have identified refugia where fauna were able to persist during unsuitable climatic periods, particularly during times of glaciation. In Australia the effects of Pleistocene climate oscillations on rainforest taxa have been well studied but less is known about the effects on mesic-habitat fauna, such as the eastern grey kangaroo (Macropus giganteus). The eastern grey kangaroo is a large mammal that is common and widespread throughout eastern Australia, preferring dry mesic habitat, rather than rainforest. As pollen evidence suggests that the central-eastern part of Australia (southeast Queensland and northern New South Wales) experienced cycles of expansion in mesic habitat with contraction in rainforests, and vice versa during glacial and interglacial periods, respectively, we hypothesise that the distribution of the eastern grey kangaroo was affected by these climate oscillations and may have contracted to mesic habitat refugia. From 375 mitochondrial DNA control region sequences from across the distribution of eastern grey kangaroos we obtained 108 unique haplotypes. Phylogenetic analysis identified two clades in Queensland, one of which is newly identified and restricted to a small coastal region in southern Queensland north of Brisbane, known as the Sunshine Coast. The relatively limited geographic range of this genetically isolated clade suggests the possibility of a mesic habitat refugium forming during rainforest expansion during wetter climate cycles. Other potential, although less likely, reasons for the genetic isolation of the highly distinct clade include geographic barriers, separate northward expansions, and strong local adaptation.Brett A. Coghlan, Anne W. Goldizen, Vicki A. Thomson, Jennifer M. Seddo

    rs5888 Variant of SCARB1 Gene Is a Possible Susceptibility Factor for Age-Related Macular Degeneration

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    Major genetic factors for age-related macular degeneration (AMD) have recently been identified as susceptibility risk factors, including variants in the CFH gene and the ARMS2 LOC387715/HTRA1locus. Our purpose was to perform a case-control study in two populations among individuals who did not carry risk variants for CFHY402H and LOC387715 A69S (ARMS2), called “study” individuals, in order to identify new genetic risk factors. Based on a candidate gene approach, we analyzed SNP rs5888 of the SCARB1 gene, coding for SRBI, which is involved in the lipid and lutein pathways. This study was conducted in a French series of 1241 AMD patients and 297 controls, and in a North American series of 1257 patients with advanced AMD and 1732 controls. Among these individuals, we identified 61 French patients, 77 French controls, 85 North American patients and 338 North American controls who did not carry the CFH nor ARMS2 polymorphisms. An association between AMD and the SCARB1 gene was seen among the study subjects. The genotypic distribution of the rs5888 polymorphism was significantly different between cases and controls in the French population (p<0.006). Heterozygosity at the rs5888 SNP increased risk of AMD compared to the CC genotypes in the French study population (odds ratio (OR) = 3.5, CI95%: 1.4–8.9, p<0.01) and after pooling the 2 populations (OR = 2.9, 95% CI: 1.6–5.3, p<0.002). Subgroup analysis in exudative forms of AMD revealed a pooled OR of 3.6 for individuals heterozygous for rs5888 (95% CI: 1.7–7.6, p<0.0015). These results suggest the possible contribution of SCARB1, a new genetic factor in AMD, and implicate a role for cholesterol and antioxidant micronutrient (lutein and vitamin E) metabolism in AMD
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