5,450 research outputs found
Simple, reproducible methods for thermal shock testing of brittle materials
Technique requires radio frequency induction power source, induction furnace and good vacuum system to induce brittle material thermal shock testing
Firewood, food and niche construction : the potential role of Mesolithic hunter-gatherers in actively structuring Scotland's woodlands.
Over the past few decades the potential role of Mesolithic hunter–gatherers in actively constructing their own niches, through the management of wild plants, has frequently been discussed. It is probable that Mesolithic hunter–gatherers systematically exploited specific woodland resources for food and fuel and influenced the ‘natural’ abundance or distribution of particular species within Mesolithic environments. Though there has been considerable discussion of the pollen evidence for potential small-scale human-woodland manipulation in Mesolithic Scotland, the archaeobotanical evidence for anthropogenic firewood and food selection has not been discussed in this context. This paper assesses the evidence for the active role of Mesolithic hunter–gatherer communities in systematically exploiting and managing woodlands for food and fuel in Scotland. While taphonomic factors may have impacted on the frequency of specific species in archaeobotanical assemblages, it is suggested that hunter–gatherers in Mesolithic Scotland were systematically using woodland plants, and in particular hazel and oak, for food and fuel. It is argued that the pollen evidence for woodland management is equivocal, but hints at the role of hunter–gatherers in shaping the structure of their environments, through the maintenance or creation of woodland clearings for settlement or as part of vegetation management strategies. It is proposed that Mesolithic hunter–gatherers may have actively contributed to niche construction and that the systematic use of hazel and oak as a fuel may reflect the deliberate pruning of hazel trees to increase nut-yields and the inadvertent – or perhaps deliberate – coppicing of hazel and oak during greenwood collection
Involution products in Coxeter groups
For W a Coxeter group, let
= {w ∈ W | w = xy where x, y ∈ W and x 2 = 1 = y 2}.
It is well known that if W is finite then W = . Suppose that w ∈ . Then the minimum value of ℓ(x) + ℓ(y) – ℓ(w), where x, y ∈ W with w = xy and x 2 = 1 = y 2, is called the excess of w (ℓ is the length function of W). The main result established here is that w is always W-conjugate to an element with excess equal to zero
Repeatable method of thermal stress fracture test of brittle materials
Method heats specimens slowly and with sufficient control so that the critical temperature gradient in the specimens cannot occur before temperature equilibrium is reached
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How do hospitals respond to feedback about blood transfusion practice? A multiple case study investigation
National clinical audits play key roles in improving care and driving system-wide change. However, effects of audit and feedback depend upon both reach (e.g. relevant staff receiving the feedback) and response (e.g. staff regulating their behaviour accordingly). This study aimed to investigate which hospital staff initially receive feedback and formulate a response, how feedback is disseminated within hospitals, and how responses are enacted (including barriers and enablers to enactment). Using a multiple case study approach, we purposively sampled four UK hospitals for variation in infrastructure and resources. We conducted semi-structured interviews with staff from transfusion-related roles and observed Hospital Transfusion Committee meetings. Interviews and analysis were based on the Theoretical Domains Framework of behaviour change. We coded interview transcripts into theoretical domains, then inductively identified themes within each domain to identify barriers and enablers. We also analysed data to identify which staff currently receive feedback and how dissemination is managed within the hospital. Members of the hospital’s transfusion team initially received feedback in all cases, and were primarily responsible for disseminating and responding, facilitated through the Hospital Transfusion Committee. At each hospital, key individuals involved in prescribing transfusions reported never having received feedback from a national audit. Whether audits were discussed and actions explicitly agreed in Committee meetings varied between hospitals. Key enablers of action across all cases included clear lines of responsibility and strategies to remind staff about recommendations. Barriers included difficulties disseminating to relevant staff and needing to amend feedback to make it appropriate for local use. Appropriate responses by hospital staff to feedback about blood transfusion practice depend upon supportive infrastructures and role clarity. Hospitals could benefit from support to disseminate feedback systematically, particularly to frontline staff involved in the behaviours being audited, and practical tools to support strategic decision-making (e.g. action-planning around local response to feedback)
Evidence of Double Phonon Excitations in ^{16}O + ^{208}Pb Reaction
The fusion cross-sections for ^{16}O + ^{208}Pb, measured to high precision,
enable the extraction of the distribution of fusion barriers. This shows a
structure markedly different from the single-barrier which might be expected
for fusion of two doubly-closed shell nuclei. The results of exact coupled
channel calculations performed to understand the observations are presented.
These calculations indicate that coupling to a double octupole phonon excited
state in ^{208}Pb is necessary to explain the experimental barrier
distributions.Comment: 6 pages, 2 figures, To be published in the Proceedings of the FUSION
97 Conference, South Durras, Australia, March 1997 (J. Phys. G
Economic rationalisation of health behaviours: the dangers of attempting policy discussions in a vacuum
When analysing the health behaviours of any group of people, understanding the constraints and possibilities for individual agency as shaped by the broader societal context is critical. In recent decades, our understanding of the ways in which physical and social environments influence health and health behaviours has expanded greatly. The authors of a recent analysis of Australian Aboriginal health data using an economic ‘rational choice model,’ published in this journal, claim to make a useful contribution to policy discussions relating to Aboriginal health, but neglect context. By doing so, they neglect the very factors that determine the success or failure of policy change. Notwithstanding the technical sophistication of the analyses, by ignoring most relevant determinants of health, the conclusions misrepresent the lives of Aboriginal and Torres Strait Islander people and therefore risk perpetuating harm, rather than improving health.Rachel Reilly, Kevin Rowley Joanne Luke Joyce Doyle Rebecca Ritte Rebekah O, Shea Alex Brow
Adaptability of Scanning Electron Microscopy to Studies of Pollen Morphology
We have explored methods to achieve excellent results in study of the pollen grain wall by using only one electron microscope, the scanning electron microscope (SEM). While the secondary electron imaging mode, the most common in use, has great value in characterizing the exine surface it is possible to obtain a more comprehensive representation of pollen grain walls by expanding the capability of the secondary mode and making use of backscatter and transmission imaging detectors. In this way information is obtained about internal exine features that are likely to be more stable phylogenetically than the generally late-to-form surface structure. We illustrate the usefulness of natural and induced fractures, cryornicrotomy, thin-section examination, section deplasticization, localized acetolysis and pollen erosion by ionic bombardment in imaging exine structure. Techniques for expanding the use of SEM in taxonomic studies of mature pollen grain walls are outlined in flow chart sketches and illustrated with numerous examples from angiosperm pollen
The BSL Sentence Reproduction Test: Exploring age of acquisition effects in British deaf adults
Here we present initial findings from a BSL sentence reproduction test, adapted from a test originally created for ASL (Hauser et al., 2008), with the aim of creating a screen that can be used to distinguish signers with native-like vs. non-native-like skills. The stimulus items, based on a set of 49 sentences from Hauser et al. (2008), included 40 BSL sentences varying in length and complexity, presented on video by a deaf native BSL signer. Participants were instructed to copy the signed sentence to camera, exactly as they saw it, regardless of phonological or lexical variants for the same concepts that they might prefer. Participants were 20 deaf adults: 10 deaf native signers, 5 deaf early learners first exposed to BSL between ages 2 and 6, and 5 late learners first exposed to BSL at age 11 or later. Responses were scored by a team of deaf and hearing sign language researchers. Responses which were agreed by all scorers as identical to the stimulus were given a score of 1; responses which included any phonological, morphological, lexical or syntactic deviations were given a score of 0 (except for a few specific, agreed-upon acceptable deviations). Results indicate that native signers scored significantly higher than non-native signers. For non-native signers there was no significant differences between early and late learners. We explore implications of these findings for use of the BSL-SRT as a screening test for assessing fluency in deaf adults and for exploring age-of-acquisition effects more generally. Hauser, P., Paludneviciene, R., Supalla, T., & Bavelier, D. (2008). American Sign Language – Sentence Reproduction Test: Development & Implications. In R. M. d. Quadros (Ed.), Sign Languages: Spinning and Unraveling the Past, Present and Future. TISLR 9, Forty-five Papers and Three Posters from the 9th Theoretical Issues in Sign Language Research Conference (pp. 155-167). Petrópolis/RJ. Brazil: Editora Arara Azul
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