569 research outputs found
Fuels and Burners for Domestic Heating
Discusses fuels and burners for domestic heating, including hand-fired coal or coke, automatic coal stoker, gas-fired heaters, oil burners. INlcudes table of comparative fuel costs
Fast soliton scattering by delta impurities
We study the Gross-Pitaevskii equation (nonlinear Schroedinger equation) with
a repulsive delta function potential. We show that a high velocity incoming
soliton is split into a transmitted component and a reflected component. The
transmitted mass (L^2 norm squared) is shown to be in good agreement with the
quantum transmission rate of the delta function potential. We further show that
the transmitted and reflected components resolve into solitons plus dispersive
radiation, and quantify the mass and phase of these solitons.Comment: 32 pages, 3 figure
Impaired CD4 T Cell Memory Response to Streptococcus pneumoniae Precedes CD4 T Cell Depletion in HIV-Infected Malawian Adults
Objective: Invasive pneumococcal disease (IPD) is a leading cause of morbidity and mortality in HIV-infected African Adults. CD4 T cell depletion may partially explain this high disease burden but those with relatively preserved T cell numbers are still at increased risk of IPD. This study evaluated the extent of pneumococcal-specific T cell memory dysfunction in asymptomatic HIV infection early on in the evolution of the disease.
Methods: Peripheral blood mononuclear cells were isolated from asymptomatic HIV-infected and HIV-uninfected Malawian
adults and stained to characterize the underlying degree of CD4 T cell immune activation, senescence and regulation.
Pneumococcal-specific T cell proliferation, IFN-c, IL-17 production and CD154 expression was assessed using flow cytometry and ELISpot.
Results: We find that in asymptomatic HIV-infected Malawian adults, there is considerable immune disruption with an
increase in activated and senescent CD4+CD38+PD-1+ and CD4+CD25highFoxp3+ Treg cells. In the context of high
pneumococcal exposure and therefore immune stimulation, show a failure in pneumococcal-specific memory T cell
proliferation, skewing of T cell cytokine production with preservation of interleukin-17 but decreased interferon-gamma responses, and failure of activated T cells to express the co-stimulatory molecule CD154.
Conclusion: Asymptomatic HIV-infected Malawian adults show early signs of pneumococcal- specific immune dysregulation
with a shift in the balance of CD4 memory, T helper 17 cells and Treg. Together these data offer a mechanistic
understanding of how antigen-specific T cell dysfunction occurs prior to T cell depletion and may explain the early susceptibility to IPD in those with relatively preserved CD4 T cell numbers
Random line tessellations of the plane: statistical properties of many-sided cells
We consider a family of random line tessellations of the Euclidean plane
introduced in a much more formal context by Hug and Schneider [Geom. Funct.
Anal. 17, 156 (2007)] and described by a parameter \alpha\geq 1. For \alpha=1
the zero-cell (that is, the cell containing the origin) coincides with the
Crofton cell of a Poisson line tessellation, and for \alpha=2 it coincides with
the typical Poisson-Voronoi cell. Let p_n(\alpha) be the probability for the
zero-cell to have n sides. By the methods of statistical mechanics we construct
the asymptotic expansion of \log p_n(\alpha) up to terms that vanish as
n\to\infty. In the large-n limit the cell is shown to become circular. The
circle is centered at the origin when \alpha>1, but gets delocalized for the
Crofton cell, \alpha=1, which is a singular point of the parameter range. The
large-n expansion of \log p_n(1) is therefore different from that of the
general case and we show how to carry it out. As a corollary we obtain the
analogous expansion for the {\it typical} n-sided cell of a Poisson line
tessellation.Comment: 26 pages, 3 figure
Forced Stratified Turbulence: Successive Transitions with Reynolds Number
Numerical simulations are made for forced turbulence at a sequence of
increasing values of Reynolds number, R, keeping fixed a strongly stable,
volume-mean density stratification. At smaller values of R, the turbulent
velocity is mainly horizontal, and the momentum balance is approximately
cyclostrophic and hydrostatic. This is a regime dominated by so-called pancake
vortices, with only a weak excitation of internal gravity waves and large
values of the local Richardson number, Ri, everywhere. At higher values of R
there are successive transitions to (a) overturning motions with local
reversals in the density stratification and small or negative values of Ri; (b)
growth of a horizontally uniform vertical shear flow component; and (c) growth
of a large-scale vertical flow component. Throughout these transitions, pancake
vortices continue to dominate the large-scale part of the turbulence, and the
gravity wave component remains weak except at small scales.Comment: 8 pages, 5 figures (submitted to Phys. Rev. E
First report of field outbreaks of ergot-alkaloid toxicity in South Africa
Outbreaks of clinical disease caused by the ingestion of ergotized Lolium rigidum (annual ryegrass),
which resulted in a substantial loss in production, have been reported. A number of outbreaks of a hyperthermia
syndrome in cattle, characterized by severe loss in milk production, loss of body mass and
reduced fertility, are described. In one major outbreak in March to April 1994, a milling company reported
that 2 646 dairy cows on 29 farms had developed clinical signs. In this outbreak, significant levels
of ergotamine, ergosine, ergocornine and ergocryptine were found in the milled dairy rations fed to
the affected cows. Barley screenings containing ergotized annual-ryegrass seed was identified as the
toxic component and probable source of the ergot alkaloids in the ration. The clinical syndrome was
reproduced experimentally by feeding suspected feed to a group of nine high-producing Ayrshire cows.
An outbreak of gangrenous necrosis of the extremities in young cattle in the winter of 1987 was also
suspected of having been caused by ergot alkaloids in grain screenings.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi.
Adobe Acrobat X Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201
Society for Endocrinology UK guidance on the initial evaluation of an infant or an adolescent with a suspected disorder of sex development (Revised 2015)
It is paramount that any child or adolescent with a suspected disorder of sex development (DSD) is assessed by an experienced clinician with adequate knowledge about the range of conditions associated with DSD. If there is any doubt, the case should be discussed with the regional DSD team. In most cases, particularly in the case of the newborn, the paediatric endocrinologist within the regional team acts commonly as the first point of contact. This clinician should be part of a multidisciplinary team experienced in management of DSD and should ensure that the affected person and parents have access to specialist psychological support and that their information needs are comprehensively addressed. The underlying pathophysiology of DSD and the strengths and weaknesses of the tests that can be performed should be discussed with the parents and affected young person and tests undertaken in a timely fashion. Finally, in the field of rare conditions, it is imperative that the clinician shares the experience with others through national and international clinical and research collaboration
Understanding the UK hospital supply chain in an era of patient choice
Author Posting © Westburn Publishers Ltd, 2011. This is a post-peer-review, pre-copy-edit version of an article which has been published in its definitive form in the Journal of Marketing Management, and has been posted by permission of Westburn Publishers Ltd for personal use, not for redistribution. The article was published in Journal of Marketing Management, 27(3-4), 401 - 423, doi:10.1080/0267257X.2011.547084 http://dx.doi.org/10.1080/0267257X.2011.547084The purpose of this paper is to investigate the UK hospital supply chain in light of recent government policy reform where patients will have, inter alia, greater choice of hospital for elective surgery. Subsequently, the hospital system should become far more competitive with supply chains having to react to these changes as patient demand becomes less predictable. Using a qualitative case study methodology, hospital managers are interviewed on a range of issues. Views on the development of the hospital supply chain in different phases are derived, and are used to develop a map of the current hospital chain. The findings show hospital managers anticipating some significant changes to the hospital supply chain and its workings as Patient Choice expands. The research also maps the various aspects of the hospital supply chain as it moves through different operational phases and highlights underlying challenges and complexities. The hospital supply chain, as discussed and mapped in this research, is original work given there are no examples in the literature that provide holistic representations of hospital activity. At the end, specific recommendations are provided that will be of interest to service to managers, researchers, and policymakers
Immunological impact of an additional early measles vaccine in Gambian children: responses to a boost at 3 years.
BACKGROUND: Measles vaccine in early infancy followed by a dose at 9 months of age protects against measles and enhances child survival through non-specific effects. Little is known of immune responses in the short or long term after booster doses. METHODS: Infants were randomized to receive measles vaccine at 9 months of age (group 1) or 4 and 9 months of age (group 2). Both groups received a boost at 36 months of age. T-cell effector and memory responses using IFN-γ ELIspot and cytokine assays and antibody titres using a haemagglutination-inhibition assay were compared at various times. RESULTS: Vaccination at 4 months of age elicited antibody and CD4 T-cell mediated immune responses .Two weeks after vaccination at 9 months of age group 2 had much higher antibody titres than group1 infants; cell-mediated effector responses were similar. At 36 months of age group 2 antibody titres exceeded protective levels but were 4-fold lower than group 1; effector and cytokine responses were similar. Re-vaccination resulted in similar rapid and high antibody titres in both groups (median 512); cellular immunity changed little. At 48 months of age group 2 antibody concentrations remained well above protective levels though 2-fold lower than group 1; T-cell memory was readily detectable and similar in both groups. CONCLUSIONS: An additional early measles vaccine given to children at 4 months of age induced a predominant CD4 T-cell response at 9 months and rapid development of high antibody concentrations after booster doses. However, antibody decayed faster in these children than in the group given primary vaccination at 9 months of age. Cellular responses after 9 months were generally insignificantly different
Anthropogenic Space Weather
Anthropogenic effects on the space environment started in the late 19th
century and reached their peak in the 1960s when high-altitude nuclear
explosions were carried out by the USA and the Soviet Union. These explosions
created artificial radiation belts near Earth that resulted in major damages to
several satellites. Another, unexpected impact of the high-altitude nuclear
tests was the electromagnetic pulse (EMP) that can have devastating effects
over a large geographic area (as large as the continental United States). Other
anthropogenic impacts on the space environment include chemical release ex-
periments, high-frequency wave heating of the ionosphere and the interaction of
VLF waves with the radiation belts. This paper reviews the fundamental physical
process behind these phenomena and discusses the observations of their impacts.Comment: 71 pages, 35 figure
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