1,070 research outputs found

    Effect of polymer properties and adherend surfaces on adhesion

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    The surface properties associated with good adhesive joints were evaluated in terms of application of adhesive bonding in aerospace technology. The physical and chemical nature was determined of Ti and Al adherend surfaces after various surface treatments, and the effects on fracture surfaces of high temperature aging, and variations in amide, anhydride, and solvent during polymer synthesis. The effects were characterized of (1) high temperature during shear strength testing, (2) fiber-reinforced composites as adherends, (3) acid/base nature of adherends, (4) aluminum powder adhesive filler, and (5) bonding pressure

    Boundary Condition on Electron Temperature for Antiforce Current Bearing Waves

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    In our investigation of breakdown waves, we apply a one-dimensional, three-component, steady-state fluid model. The wave is considered to be shock fronted and the electrons are assumed to be the main element in propagation of the wave. In our fluid model, the electron gas temperature is assumed to be large enough to sustain the wave motion. Our set of fluid equations is composed of the equations of conservation of mass, momentum and energy plus the Poisson’s equation. This investigation involves breakdown waves for which a large current exist in the vicinity of the wave front. Existence of current behind the wave front alters the equation of conservation of energy and also the Poisson’s equation. Therefore, the boundary conditions at the shock front will change as well. For current bearing breakdown waves we will derive the appropriate boundary condition for electron temperature, and using the new boundary condition, we will integrate the fluid dynamical equations through the dynamical transition region of the wav

    Study of Beauty Hadron Decays into Pairs of Charm Hadrons

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    First observations of the decays Λ[0 over b] → Λ[+ over c]D[− over (s)] are reported using data corresponding to an integrated luminosity of 3  fb[superscript −1] collected at 7 and 8 TeV center-of-mass energies in proton-proton collisions with the LHCb detector. In addition, the most precise measurement of the branching fraction B(B[0 over s] → D[superscript +]D[− over s]) is made and a search is performed for the decays B[0 over (s)] → Λ[+ over c]Λ[− over c]. The results obtained are B(Λ[0 over b] → Λ[+ over c]D[superscript −])/B(Λ[0 over b] → Λ[+ over c]D[− over s]) = 0.042 ± 0.003(stat) ± 0.003(syst), ⎡⎣B(Λ[0 over b] → Λ[+ over c]D[− over s]) over B([¯ over B[superscript 0] → D[superscript +]D[− over s])⎤⎦/⎡⎣B(Λ[0 over b] → Λ[+ over c]π[superscript −]) over B([¯ over B[superscript 0] → D[superscript +]π[superscript −])⎤⎦ = 0.96 ± 0.02(stat) ± 0.06(syst), B(B[0 over s] → D[superscript +]D[− over s])/B([¯ over B][superscript 0] → D[superscript +]D[− over s]) = 0.038 ± 0.004(stat) ± 0.003(syst), B([¯ over B][superscript 0] → Λ[+ over c]Λ[− over c])/B([¯ over B][superscript 0] → D[superscript +]D[− over s]) < 0.0022[95%  C.L.], B(B[0 over s] → Λ[+ over c]Λ[− over c])/B(B[0 over s] → D[superscript +]D[− over s]) < 0.30[95%  C.L.]. Measurement of the mass of the Λ[0 over b] baryon relative to the [¯ over B][superscript 0] meson gives M(Λ[0 over b]) − M([¯ over B][superscript 0]) = 339.72 ± 0.24(stat) ± 0.18(syst)  MeV/c[superscript 2]. This result provides the most precise measurement of the mass of the Λ[0 over b] baryon to date.National Science Foundation (U.S.

    Evaluation Development and Use in Social Work Practice

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    Background: Social workers entering the profession typically receive little, if any, content or training on evaluation practice. This is, in part, due to limited course offerings outside of the typical courses in most schools of social work. In addition, practicing social workers who often serve in the role as field instructors have not fully embraced the use of research in practice, and tend to employ less rigorous evaluative methods. &nbsp; Purpose: The purpose of this study was to explore the development and use of evaluation knowledge among social work practitioners who supervise social work students. &nbsp; Setting: Not applicable. &nbsp; Intervention: Not applicable. &nbsp; Research Design: A mixed method, sequential research design within the context of an exploratory study was used to determine factors that facilitate evaluation, identify and prioritize evaluation competencies, and determine the extent to which evaluation constructs contribute to self efficacy, evaluation competency, evaluation influence, and leadership behaviors. &nbsp; Data Collection and Analysis: A web-based survey was used followed by a participatory method that included the use of a web-based software to identify and prioritize activities that contribute to the development of evaluation knowledge and skill. &nbsp; Findings: Results suggest social work education has a critical role in promoting evaluation practice, establishing evaluation practice competencies, and using evaluation results to inform policy and practice. &nbsp; Keywords: social work practice, field education, evaluation practice, Council on Social Work Education (CSWE), Educational Policy, and Accreditation Standards (EPAS

    Nerve Growth Factor Pathobiology During The Progression Of Alzheimer\u27s Disease

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    The current review summarizes the pathobiology of nerve growth factor (NGF) and its cognate receptors during the progression of Alzheimer’s disease (AD). Both transcript and protein data indicate that cholinotrophic neuronal dysfunction is related to an imbalance between TrkA-mediated survival signaling and the NGF precursor (proNGF)/p75NTR-mediated pro-apoptotic signaling, which may be related to alteration in the metabolism of NGF. Data indicate a spatiotemporal pattern of degeneration related to the evolution of tau pathology within cholinotrophic neuronal subgroups located within the nucleus basalis of Meynert (nbM). Despite these degenerative events the cholinotrophic system is capable of cellular resilience and/or plasticity during the prodromal and later stages of the disease. In addition to neurotrophin dysfunction, studies indicate alterations in epigenetically regulated proteins occur within cholinotrophic nbM neurons during the progression of AD, suggesting a mechanism that may underlie changes in transcript expression. Findings that increased cerebrospinal fluid levels of proNGF mark the onset of MCI and the transition to AD suggests that this proneurotrophin is a potential disease biomarker. Novel therapeutics to treat NGF dysfunction include NGF gene therapy and the development of small molecule agonists for the cognate prosurvival NGF receptor TrkA and antagonists against the pan-neurotrophin p75NTR death receptor for the treatment of AD

    The effectiveness of an intensive individual tutoring programme (Numbers Count) delivered individually or to small groups of children: a randomised controlled trial

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    Introduction: In this article, we present the results of two small randomised controlled trials (RCTs) investigating the relative efficacy of a one-to-one numeracy programme, Numbers Count (NC). This intervention was developed as part of the Every Child Counts programme to specifically target the lowest achieving children at key stage 1 (KS1) mathematics. The research question focused on the relative efficacy of NC delivered either individually (as originally intended by the developers of the programme) or in an adapted version to small groups of two or three children. Design and methods: In 15 schools 75 children in year 2 identified by the schools as being eligible to receive NC were randomised to receive it individually or in pairs and in 7 schools 54 children in year 2 identified by the schools as being eligible to receive NC were randomised to receive it individually or in triplets during the school year 2009–2010. The design of the trial required five children, for the pairs sub-trial, or seven children for the triplets sub-trial in each school to receive NC individually or in pairs/triplets in autumn term 2009 or spring term 2010. Results: The primary outcome measure Progress in Maths 6 (PIM 6) was undertaken and marked blind to group allocation by independent testers. We found no statistically significant difference between the scores of the children taught individually or in pairs in terms of PIM 6 scores although a slight difference in favour of pairs was observed. We also found no statistically significant differences between children taught individually or in triplets in terms of PIM 6 scores. We pooled the effect sizes for individual versus pairs and triplets delivery in a meta-analysis of individual versus small group teaching. The pooled effect size was −.26 (CI −2.18 to 1.65) which demonstrates no statistically significant difference between individual and small group teaching. Conclusion: There was no evidence of a difference between the groups, which was not unexpected as our sample sizes were relatively small. This is the only robust evidence from RCTs of the promise of the intervention. However, given the small sample sizes of the trials, we recommend further larger trials should be undertaken comparing small group mathematics teaching with one-to-one educational interventions, using both this programme and others. These two trials could also usefully be included in meta-analyses comparing small group and one-to-one teaching in mathematics education

    The Mississippian Section at Paddys Bluff, Crittenden County, Kentucky

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    Paddys Bluff (Figs. 1-3) is located on the south side of the Illinois Basin on the Cumberland River, 1.7 miles downstream from Dycusburg in Crittenden County, Ky., in Carter coordinate section 23-I-16 and ecoregion 71f of the Western Highland Rim of Kentucky (Woods and others, 2002). This bluff is on a right-descending bend 18 liver miles above its junction with the Ohio River at Smithland, Livingston County. The bluff (Figs. 4A, B) is locally famous as the location for a scene from the classic 1962 film, How the West Was Won,\u27 a winner of three Academy Awards, starling James Stewart, John Wayne, and others. We observed Paddys Bluff from the starboard Texas deck of the steamboat Della Queen one rainy morning in October 2005; the thick, persistent white bed midway in the bluff especially attracted our attention (Fig. 4). Paddys Bluff is the best natural exposure of Mississippian limestone between Barkley Dam and the Ohio River, a distance of 31 river miles. The bluff, some 1,700 feet long (Fig. 4), rises 160 feet above the Cumberland River and deflects it about 16° into a long westward reach, the river removing all talus at the base of the bluff. The bluff lies in a graben between two inferred faults st liking N40 to 45°E (Amos and Hayes, 1974). Readily seen in the limestones along the river at the base of the bluff is a prominent joint set parallel to these faults. This bluff is mapped on the Dycusburg geologic quadrangle map (Table 1) as the combined Salem and St. Louis Limestones (Amos and Hayes, 1974) and is capped by at least 15 feet of poorly exposed gravel of the Cretaceous Tuscaloosa Formation (Olive, 1980). Across the river less than 2 miles distant are scattered continental deposits of reddish brown Lafayette-type, sandy cobble-gravel (Olive, 1980), below which are outliers of the Cretaceous Tuscaloosa Formation; both cap hilltops of the same underlying Mississippian limestones. Why is Paddys Bluff of interest? There are at least six reasons to study it. First, can the Salem and St. Louis Limestones be individually identified at the bluff? If, in fact, they can be separated, the upper boundary of sequence S4 recognized in the Lake Cumberland area of south-central Kentucky by Khetani and Read (2002, Fig. 12) extends much farther west. Still another challenge is the enigmatic, massive, fine-grained, whitish-weathering carbonate mudstone bed, unit C of our section, high in the bluff. What does it represent? How widespread is it? Why do beds below rt have a strong petroliferous odor and not those above it? Why are some of the coral heads (Fig. 5) at Paddys Bluff overturned and others not? The last challenge is the bluff itself: Why is it there and how long has it been there

    Amelioration of bleomycin-induced lung fibrosis in hamsters by dietary supplementation with taurine and niacin: biochemical mechanisms.

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    Interstitial pulmonary fibrosis induced by intratracheal instillation of bleomycin (BL) involves an excess production of reactive oxygen species, unavailability of adequate levels of NAD and ATP to repair the injured pulmonary epithelium, and an overexuberant lung collagen reactivity followed by deposition of highly cross-linked mature collagen fibrils resistant to enzymatic degradation. In the present study, we have demonstrated that dietary supplementation with taurine and niacin offered almost complete protection against the lung fibrosis in a multidose BL hamster model. The mechanisms for the protective effect of taurine and niacin are multifaceted. These include the ability of taurine to scavenge HOCl and stabilize the biomembrane; niacin's ability to replenish the BL-induced depletion of NAD and ATP; and the combined effect of taurine and niacin to suppress all aspects of BL-induced increases in the lung collagen reactivity, a hallmark of interstitial pulmonary fibrosis. It was concluded from the data presented at this Conference that the combined treatment with taurine and niacin, which offers a multipronged approach, will have great therapeutic potential in the intervention of the development of chemically induced interstitial lung fibrosis in animals and humans

    Gendered endings: Narratives of male and female suicides in the South African Lowveld

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    This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s11013-012-9258-y. Copyright @ Springer Science+Business Media, LLC 2012.Durkheim’s classical theory of suicide rates being a negative index of social solidarity downplays the salience of gendered concerns in suicide. But gendered inequalities have had a negative impact: worldwide significantly more men than women perpetrate fatal suicides. Drawing on narratives of 52 fatal suicides in Bushbuckridge, South Africa, this article suggests that Bourdieu’s concepts of ‘symbolic violence’ and ‘masculine domination’ provide a more appropriate framework for understanding this paradox. I show that the thwarting of investments in dominant masculine positions have been the major precursor to suicides by men. Men tended to take their own lives as a means of escape. By contrast, women perpetrated suicide to protest against the miserable consequences of being dominated by men. However, contra the assumption of Bourdieu’s concept of ‘habitus’, the narrators of suicide stories did reflect critically upon gender constructs
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