111,740 research outputs found
The distribution of species range size: a stochastic process
The major role played by environmental factors in determining the geographical range sizes of species raises the possibility of describing their long-term dynamics in relatively simple terms, a goal which has hitherto proved elusive. Here we develop a stochastic differential equation to describe the dynamics of the range size of an individual species based on the relationship between abundance and range size, derive a limiting stationary probability model to quantify the stochastic nature of the range size for that species at steady state, and then generalize this model to the species-range size distribution for an assemblage. The model fits well to several empirical datasets of the geographical range sizes of species in taxonomic assemblages, and provides the simplest explanation of species-range size distributions to date
Librarians as Members of Integrated Institutional Information Programs: Management and Organizational Issues
published or submitted for publicatio
Does Community and Environmental Responsibility Affect Firm Risk? Evidence from UK Panel Data 1994-2006
The question of how an individual firm’s environmental performance impacts its firm risk has not been examined in any empirical UK research. Does a company that strives to attain good environmental performance decreases its market risk or is environmental performance just a disadvantageous cost that increases such risk levels for these firms? Answers to this question have important implications for the management of companies and the investment decisions of individuals and institutions. The purpose of this paper is to examine the relationship between corporate environmental performance and firm risk in the British context. Using the largest dataset so far assembled, with Community and Environmental Responsibility (CER) rankings for all rated UK companies between 1994 and 2006, we show that a company’s environmental performance is inversely related to its systematic financial risk. However, an increase of 1.0 in the CER score is associated with only a 0.02 reduction in firm’s risk and cost of capital
Interleukin-12 p40 secretion by cutaneous CD11c(+) and F4/80(+) cells is a major feature of the innate immune response in mice that develop Th1-mediated protective immunity to Schistosoma mansoni
Radiation-attenuated (RA) schistosome larvae are potent stimulators of innate immune responses at the skin site of exposure (pinna) that are likely to be important factors in the development of Th1-mediated protective immunity. In addition to causing an influx of neutrophils, macrophages, and dendritic cells (DCs) into the dermis, RA larvae induced a cascade of chemokine and cytokine secretion following in vitro culture of pinna biopsy samples. While macrophage inflammatory protein 1alpha and interleukin-1beta (IL-1beta) were produced transiently within the first few days, the Th1-promoting cytokines IL-12 and IL-18 were secreted at high levels until at least day 14. Assay of C3H/HeJ mice confirmed that IL-12 secretion was not due to lipopolysaccharide contaminants binding Toll-like receptor 4. Significantly, IL-12 p40 secretion was sustained in pinnae from vaccinated mice but not in those from nonprotected infected mice. In contrast, IL-10 was produced from both vaccinated and infected mice. This cytokine regulates IL-12-associated dermal inflammation, since in vaccinated IL-10(-/-) mice, pinna thickness was greatly increased concurrent with elevated levels of IL-12 p40. A significant number of IL-12 p40(+) cells were detected as emigrants from in vitro-cultured pinnae, and most were within a population of rare large granular cells that were Ia(+), consistent with their being antigen-presenting cells. Labeling of IL-12(+) cells for CD11c, CD205, CD8alpha, CD11b, and F4/80 indicated that the majority were myeloid DCs, although a proportion were CD11c(-) F4/80(+), suggesting that macrophages were an additional source of IL-12 in the skin
Rapid Thermal Processing (RTP) of semiconductors in space
The progress achieved on the project entitled 'Rapid Thermal Processing of Semiconductors in Space' for a 12 month period of activity ending March 31, 1993 is summarized. The activity of this group is being performed under the direct auspices of the ROMPS program. The main objective of this program is to develop and demonstrate the use of advanced robotics in space with rapid thermal process (RTP) of semiconductors providing the test technology. Rapid thermal processing is an ideal processing step for demonstration purposes since it encompasses many of the characteristics of other processes used in solid state device manufacturing. Furthermore, a low thermal budget is becoming more important in existing manufacturing practice, while a low thermal budget is critical to successful processing in space. A secondary objective of this project is to determine the influence of microgravity on the rapid thermal process for a variety of operating modes. In many instances, this involves one or more fluid phases. The advancement of microgravity processing science is an important ancillary objective
The Final Remnant of Binary Black Hole Mergers: Multipolar Analysis
Methods are presented to define and compute source multipoles of dynamical
horizons in numerical relativity codes, extending previous work from the
isolated and dynamical horizon formalisms in a manner that allows for the
consideration of horizons that are not axisymmetric. These methods are then
applied to a binary black hole merger simulation, providing evidence that the
final remnant is a Kerr black hole, both through the (spatially)
gauge-invariant recovery of the geometry of the apparent horizon, and through a
detailed extraction of quasinormal ringing modes directly from the strong-field
region.Comment: 12 pages, 13 figures. Published version. Some references have been
added and reordered, and the figures cleaned up
Incipient order in the t-J model at high temperatures
We analyze the high-temperature behavior of the susceptibilities towards a
number of possible ordered states in the t-J-V model using the high-temperature
series expansion. From all diagrams with up to ten edges, reliable results are
obtained down to temperatures of order J, or (with some optimism) to J/2. In
the unphysical regime, t<J, large superconducting susceptibilities are found,
which moreover increase with decreasing temperatures, but for t>J, these
susceptibilities are small and decreasing with decreasing temperature; this
suggests that the t-J model does not support high-temperature
superconductivity. We also find modest evidence of a tendency toward nematic
and d-density wave orders.
ERRATUM: Due to an error in the calculation, the series for d-wave
supeconducting and extended s-wave superconducting orders were incorrect. We
recalculate the series and give the replacement figures. In agreement with our
earlier findings, we still find no evidence of any strong enhancement of the
superconducting susceptibility with decreasing temperature. However, because
different Pade approximants diverge from each other at somewhat higher
temperatures than we originally found, it is less clear what this implies
concerning the presence or absence of high-temperature superconductivity in the
t-J model.Comment: 4 pages, 5 eps figures included; ERRATUM 2 pages, 3 eps figures
correcting the error in the series for superconducting susceptibilitie
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What is the impact of psychiatric decision units on mental health crisis care pathways? Protocol for an interrupted time series analysis with a synthetic control study
Background
The UK mental health system is stretched to breaking point. Individuals presenting with mental health problems wait longer at the ED than those presenting with physical concerns and finding a bed when needed is difficult – 91% of psychiatric wards are operating at above the recommended occupancy rate. To address the pressure, a new type of facility – psychiatric decision units (also known as mental health decision units) – have been introduced in some areas. These are short-stay facilities, available upon referral, targeted to help individuals who may be able to avoid an inpatient admission or lengthy ED visit. To advance knowledge about the effectiveness of this service for this purpose, we will examine the effect of the service on the mental health crisis care pathway over a 4-year time period; the 2 years proceeding and following the introduction of the service. We use aggregate service level data of key indicators of the performance of this pathway.
Methods
Data from four mental health Trusts in England will be analysed using an interrupted time series (ITS) design with the primary outcomes of the rate of (i) ED psychiatric presentations and (ii) voluntary admissions to mental health wards. This will be supplemented with a synthetic control study with the same primary outcomes, in which a comparable control group is generated for each outcome using a donor pool of suitable National Health Service Trusts in England. The methods are well suited to an evaluation of an intervention at a service delivery level targeting population-level health outcome and the randomisation or ‘trialability’ of the intervention is limited. The synthetic control study controls for national trends over time, increasing our confidence in the results. The study has been designed and will be carried out with the involvement of service users and carers.
Discussion
This will be the first formal evaluation of psychiatric decision units in England. The analysis will provide estimates of the effect of the decision units on a number of important service use indicators, providing much-needed information for those designing service pathways
Therapeutic Opportunities in Infectious Diseases: Highlights from the Society of Medicines Research Symposium, held on March 14th 2013 at the National Heart & Lung Institute, London, UK
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