492 research outputs found
The longitudinal cascade development of cosmic-ray showers from observations of atmospheric Cerenkov radiation
This thesis is concerned with the measurement of the longitudinal cascade development of large cosmic-ray showers from observations of atmospheric Cerenkov radiation. The purpose of the measurements is to obtain information on the mass composition of the primary cosmic rays and on the gross features of the high-energy hadronic interactions. The characteristics of the Cerenkov light signal which are strongly coupled to the longitudinal shower development are described with reference to computer simulation results. An experiment designed to measure these characteristics was deployed in Dugway, Utah, U.S.A. between October 1977 and March 1980. Measurements were made in showers of primary energy 10(^15) – 10(^18) eV. Existing data analysis techniques have been refined and new procedures developed in order to optimise the reduction of the digital data. A detailed analysis is given of two aspects of the time structure of the Cerenkov light signal in showers of mean primary energy ~ 2 x 10(^17) eV. The measurements are interpreted in terms of the mean depth of electron cascade maximum and the fluctuations occurring between showers. The many results on the cascade development currently available from the Dugway data are summarised. Interpretation of the results is found to be possible in the framework of scaling-based models of the high energy hadronic interactions which incorporate an enhancement of the central-region multiplicity. This allows certain inferences to be made concerning the primary mass composition. Specifically, primaries of energy ~ 10(^16) eV appear to be predominantly heavy nuclei, and the mass composition becomes lighter with increasing primary energy until at least ~ 2 x 10(^17) eV. While no other single experiment has yet been in a position to corroborate these results, broad consistency is found between the Dugway results and the combined results from a number of other experiments
Do GPs want or need formal support following a patient suicide?: a mixed methods study.
BACKGROUND: Patient suicide can be a devastating event for some general practitioners (GPs). Few guidelines exist to aid or support GPs in the aftermath of patient suicide. AIM: To explore GPs views on how they are affected by a patient suicide and the formal support available to them following a patient suicide. DESIGN: Questionnaires and semi-structured interviews. SETTING: General practices in the northwest of England. METHODS: About 198 semi-structured interviews were conducted as part of a retrospective study. Interviews were transcribed verbatim and analysed using descriptive statistics and a framework thematic approach. RESULTS: GPs were aged between 31 and 67 years, 144 (73%) were male and the number of years in practice varied between 8 and 40 years (median = 24 years). GPs were based at 133 (67%) urban and 65 (33%) rural practices, 30 (15%) were single-handed GP practices and 168 (85%) practices had two or more GPs. About 131 (66%) GPs reported being affected by patient suicide through feelings of grief, guilt and self-scrutiny. A greater number of years in practice may have been protective against these effects. About 54 (27%) GPs reported having mostly 'informal' support from peers or colleagues and support was less available to younger and single handed GPs. CONCLUSIONS: Our findings suggest that the majority of GPs are affected by patient suicide and most seek informal support from their peers and colleagues. Although many indicated that informal support systems were adequate and provided a protective environment, procedures should be developed to ensure the availability of guidelines for those who may require formal support
Global Health Research in an Unequal World
This book is a collection of fictionalised case studies of everyday ethical dilemmas and challenges, encountered in the process of conducting global health research in places where the effects of global, political and economic inequality are particularly evident. It is a training tool to fill the gap between research ethics guidelines, and their implementation 'on the ground'. The case studies, therefore, focus on 'relational' ethics: ethical actions and ideas that emerge through relations with others, rather than in regulations
Challenges in Collaborative HRI for Remote Robot Teams
Collaboration between human supervisors and remote teams of robots is highly
challenging, particularly in high-stakes, distant, hazardous locations, such as
off-shore energy platforms. In order for these teams of robots to truly be
beneficial, they need to be trusted to operate autonomously, performing tasks
such as inspection and emergency response, thus reducing the number of
personnel placed in harm's way. As remote robots are generally trusted less
than robots in close-proximity, we present a solution to instil trust in the
operator through a `mediator robot' that can exhibit social skills, alongside
sophisticated visualisation techniques. In this position paper, we present
general challenges and then take a closer look at one challenge in particular,
discussing an initial study, which investigates the relationship between the
level of control the supervisor hands over to the mediator robot and how this
affects their trust. We show that the supervisor is more likely to have higher
trust overall if their initial experience involves handing over control of the
emergency situation to the robotic assistant. We discuss this result, here, as
well as other challenges and interaction techniques for human-robot
collaboration.Comment: 9 pages. Peer reviewed position paper accepted in the CHI 2019
Workshop: The Challenges of Working on Social Robots that Collaborate with
People (SIRCHI2019), ACM CHI Conference on Human Factors in Computing
Systems, May 2019, Glasgow, U
Can Deep Water Exercise Training Improve Arterial Stiffness in Women with Metabolic Syndrome?
Please refer to the pdf version of the abstract located adjacent to the title
Global health research in an unequal world: ethics case studies from Africa
This book is a collection of fictionalised case studies of everyday ethical dilemmas and challenges, encountered in the process of conducting global health research in places where the effects of global, political and economic inequality are particularly evident. It is a training tool to fill the gap between research ethics guidelines, and their implementation 'on the ground'. The case studies, therefore, focus on 'relational' ethics: ethical actions and ideas that emerge through relations with others, rather than in regulations
Polycyclic aromatic hydrocarbon processing in a hot gas
Context: PAHs are thought to be a ubiquitous and important dust component of
the interstellar medium. However, the effects of their immersion in a hot
(post-shock) gas have never before been fully investigated. Aims: We study the
effects of energetic ion and electron collisions on PAHs in the hot post-shock
gas behind interstellar shock waves. Methods: We calculate the ion-PAH and
electron-PAH nuclear and electronic interactions, above the carbon atom loss
threshold, in H II regions and in the hot post-shock gas, for temperatures
ranging from 10^3 to 10^8 K. Results: PAH destruction is dominated by He
collisions at low temperatures (T < 3x10^4 K), and by electron collisions at
higher temperatures. Smaller PAHs are destroyed faster for T < 10^6 K, but the
destruction rates are roughly the same for all PAHs at higher temperatures. The
PAH lifetime in a tenuous hot gas (n_H ~ 0.01 cm^-3, T ~ 10^7 K), typical of
the coronal gas in galactic outflows, is found to be about thousand years,
orders of magnitude shorter than the typical lifetime of such objects.
Conclusions: In a hot gas, PAHs are principally destroyed by electron
collisions and not by the absorption of X-ray photons from the hot gas. The
resulting erosion of PAHs occurs via C_2 loss from the periphery of the
molecule, thus preserving the aromatic structure. The observation of PAH
emission from a million degree, or more, gas is only possible if the emitting
PAHs are ablated from dense, entrained clumps that have not yet been exposed to
the full effect of the hot gas.Comment: 16 pages, 11 figures, 3 tables, typos corrected and PAH acronym in
the title substituted with full name to match version published in Astronomy
and Astrophysic
Relationships between Peak Oxygen Uptake and Arterial Function: a Preliminary Study
Please view abstract in the attached PDF file
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