Tribomaterial factors in space mechanism brake performance

The asbestos/phenolic pads of Shuttle Remote Manipulator System (SRMS) brakes are unsuitable for use in long life space mechanisms because their friction decreases on extended sliding in high vacuum. Dehydration of the material and accumulation of wear debris in the conforming interface of this tribosystem induces the permanent friction changes. Other polymer and some ceramic based materials exhibit similar frictional torque behavior due to the development of minimal contact patches by the interfacial debris. In contrast, high friction occurs when other ceramics form many small contacts throughout fine debris beds. Generating this latter interfacial structure during run-in ensures that the in-vacuo friction remains stable thereafter. Such materials with low wear rates are potential candidates for friction elements in SSRMS and similar mechanisms

Trade negotiations: teaching consensus

International negotiations, particularly in international organisations with a large number of members, can be long and fraught. Reaching consensus between a large number of countries is not an easy task and this point is often ignored in news reports relating to international negotiations. This article argues that when teaching students about the conduct of international negotiations, their understanding can be greatly enhanced by the use of active learning techniques such as role playing, simulations and games. However, much of the literature describes simulations which take time to prepare and are often run over several hours or days. This article argues that we need to develop shorter, seminar length simulations which students can relate to, in order to help their understanding of the issues and processes around negotiations. Highlighting the consensus process in the World Trade Organisation (WTO) and drawing on experience of teaching students about the WTO, this article elaborates a seminar length exercise which can be used to illustrate some of the negotiation processes in the WTO, while at the same time teaching students about the process and difficulties of consensus building with a familiar scenario

A Plan of Farm Organization for Hill Land Farms in Southeastern Ohio

Exact date of bulletin unknown.PDF pages: 2

Wood-Nymph

Photograph of woman standing in woods; Illustration of vines and leaves surrounding photographhttps://scholarsjunction.msstate.edu/cht-sheet-music/6840/thumbnail.jp

The Captive : March and Two Step

https://digitalcommons.library.umaine.edu/mmb-ps/1780/thumbnail.jp

The discord between discourse and data in engendering resilience building for sustainability

This paper explores how gender is considered in the resilience discourse, and the extent to which there is an evidence base to support the targeting of women in resilience programmes. The paper provides an overview of the approaches adopted in the fields of gender and development and gender and environment, and the critiques of these approaches. Mainstream approaches to engendering policy and practice are charged with being essentialist and instrumentalist, drawing on women’s ‘natural’ attributes and altruism, placing women at the service of the policy agenda, rather than served by it. Despite these critiques it highlights how these approaches have been borrowed by ‘newer’ policy arenas such as disasters and within this, resilience building. An analysis of the gendered language in resilience highlights a contradictory discourse, presenting women as vulnerable and as agents for change, and an explicit instrumentalism. The paper notes that in the disaster resilience discourse much of the focus actually remains on vulnerability, problematising this and how vulnerability/resilience are defined and measured generally, and in gender terms. The pseudo-scientific constructions of ‘objective’ knowledge at the base of much policy are critiqued from a feminist theoretical and practical perspective. It concludes that there is no reliable evidence base on which to base any policy moves to ‘engender’ resilience. As such the focus on women in resilience must be based on gendered assumptions and/or other policy aims, and as such the inclusion of women in resilience building is more about efficiency, than about equality

A Locality-Oriented Public Welfare Agency: A Case Study of Boundary Maintenance in a Hostile Environment

Boundary maintenance activities are studied in a public welfare agency as a means of establishing the relationship between the nature of these activities and the essential character of a formal organization. Assaults on the agency are observed through a period of social change, in this case an extreme of racial succession among the staff and administration of the agency. Conclusions point to congruence between the character of the organization and its boundary maintenance activity. Skewed or incongruent boundary maintenance produces disorganization and confusion among participants. In the context of racial succession, universalistic patterns are recommended as a solution to the confusion

The semantic effects of verb raising and its consequences in second language grammars

This article considers whether highly proficient second language speakers of English can distinguish meaning contrasts associated with constructions where there is a raising be, and constructions where there is a non-raising thematic verb, as illustrated in the difference between (1a) and (1b): 1a. Kim is reading a novel (`event-in-progress/existential ? interpretation

Effectiveness of Helminth Therapy in the Prevention of Allograft Rejection: A Systematic Review of Allogeneic Transplantation.

Background: The unique immunomodulatory capacity of helminth parasites has been investigated as a novel strategy in the prevention of allograft rejection after transplantation. This review was conducted to fully evaluate the specific effects of helminth therapy on allograft survival reported in published studies of animal models of allogeneic transplantation. Method: Following PRISMA protocol guidelines, a literature search was conducted using PubMed, MEDLINE via OvidSP, along with additional manual searches of selected reference lists. Publications describing helminth intervention within allograft transplantation models were screened for relevance to eligibility criteria. Primary and secondary outcomes were extracted using standardized data collection tables. The SYRCLE risk of bias assessment tool was used for quality assessment. Due to heterogeneity of study designs, meta-analysis could not be performed; rather outcomes are presented as a narrative synthesis with concept mapping. This review was registered in PROSPERO with ID: CRD42018097175. Results: The literature search generated 1,443 publications, which after screening for relevance to the eligibility criteria yielded 15 publications for qualitative analysis. All 15 publications reported improvement to allograft survival as a result of helminth therapy. This prolonged allograft survival was not significantly different when helminth-derived products were used compared to live infection. However, the extent of positive impact on allograft survival was noted to be dependent on study design factors, such as the chronicity of the live helminth infection, allograft type and the species/genus of helminth selected. Conclusion: Both live and product-based helminth therapy have potential applications as novel immune regulators or adjuncts for the prevention of allograft rejection. However, there were differences in efficacy between different worms and preparations of worm-derived products. Therefore, further studies are required to determine the most appropriate worm for a specific allograft, to elucidate the optimal dose and route of administration, and to better understand the modulation of immune responses that can mediate tolerance

Molecular determinants of ginkgolide binding in the glycine receptor pore

Ginkgolides are potent blockers of the glycine receptor Cl- channel (GlyR) pore. We sought to identify their binding sites by comparing the effects of ginkgolides A, B and C and bilobalide on alpha1, alpha2, alpha1beta and alpha2beta GlyRs. Bilobalide sensitivity was drastically reduced by incorporation of the beta subunit. In contrast, the sensitivities to ginkgolides B and C were enhanced by beta subunit expression. However, ginkgolide A sensitivity was increased in the alpha2beta GlyR relative to the alpha2 GlyR but not in the alpha1beta GlyR relative to the alpha1 GlyR. We hypothesised that the subunit-specific differences were mediated by residue differences at the second transmembrane domain 2' and 6' pore-lining positions. The increased ginkgolide A sensitivity of the alpha2beta GlyR was transferred to the alpha1beta GlyR by the G2'A (alpha1 to alpha2 subunit) substitution. In addition, the alpha1 subunit T6'F mutation abolished inhibition by all ginkgolides. As the ginkgolides share closely related structures, their molecular interactions with pore-lining residues were amenable to mutant cycle analysis. This identified an interaction between the variable R2 position of the ginkgolides and the 2' residues of both alpha1 and beta subunits. These findings provide strong evidence for ginkgolides binding at the 2' pore-lining position