3,264 research outputs found

    Embedding Population Dynamics Models in Inference

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    Increasing pressures on the environment are generating an ever-increasing need to manage animal and plant populations sustainably, and to protect and rebuild endangered populations. Effective management requires reliable mathematical models, so that the effects of management action can be predicted, and the uncertainty in these predictions quantified. These models must be able to predict the response of populations to anthropogenic change, while handling the major sources of uncertainty. We describe a simple ``building block'' approach to formulating discrete-time models. We show how to estimate the parameters of such models from time series of data, and how to quantify uncertainty in those estimates and in numbers of individuals of different types in populations, using computer-intensive Bayesian methods. We also discuss advantages and pitfalls of the approach, and give an example using the British grey seal population.Comment: Published at http://dx.doi.org/10.1214/088342306000000673 in the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

    Software requirements: Guidance and control software development specification

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    The software requirements for an implementation of Guidance and Control Software (GCS) are specified. The purpose of the GCS is to provide guidance and engine control to a planetary landing vehicle during its terminal descent onto a planetary surface and to communicate sensory information about that vehicle and its descent to some receiving device. The specification was developed using the structured analysis for real time system specification methodology by Hatley and Pirbhai and was based on a simulation program used to study the probability of success of the 1976 Viking Lander missions to Mars. Three versions of GCS are being generated for use in software error studies

    Optoacoustic solitons in Bragg gratings

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    Optical gap solitons, which exist due to a balance of nonlinearity and dispersion due to a Bragg grating, can couple to acoustic waves through electrostriction. This gives rise to a new species of ``gap-acoustic'' solitons (GASs), for which we find exact analytic solutions. The GAS consists of an optical pulse similar to the optical gap soliton, dressed by an accompanying phonon pulse. Close to the speed of sound, the phonon component is large. In subsonic (supersonic) solitons, the phonon pulse is a positive (negative) density variation. Coupling to the acoustic field damps the solitons' oscillatory instability, and gives rise to a distinct instability for supersonic solitons, which may make the GAS decelerate and change direction, ultimately making the soliton subsonic.Comment: 5 pages, 3 figure

    An evaluation of Bradfordizing effects

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    The purpose of this paper is to apply and evaluate the bibliometric method Bradfordizing for information retrieval (IR) experiments. Bradfordizing is used for generating core document sets for subject-specific questions and to reorder result sets from distributed searches. The method will be applied and tested in a controlled scenario of scientific literature databases from social and political sciences, economics, psychology and medical science (SOLIS, SoLit, USB Köln Opac, CSA Sociological Abstracts, World Affairs Online, Psyndex and Medline) and 164 standardized topics. An evaluation of the method and its effects is carried out in two laboratory-based information retrieval experiments (CLEF and KoMoHe) using a controlled document corpus and human relevance assessments. The results show that Bradfordizing is a very robust method for re-ranking the main document types (journal articles and monographs) in today’s digital libraries (DL). The IR tests show that relevance distributions after re-ranking improve at a significant level if articles in the core are compared with articles in the succeeding zones. The items in the core are significantly more often assessed as relevant, than items in zone 2 (z2) or zone 3 (z3). The improvements between the zones are statistically significant based on the Wilcoxon signed-rank test and the paired T-Test

    Primary vs. Secondary Antibody Deficiency: Clinical Features and Infection Outcomes of Immunoglobulin Replacement

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    <div><p>Secondary antibody deficiency can occur as a result of haematological malignancies or certain medications, but not much is known about the clinical and immunological features of this group of patients as a whole. Here we describe a cohort of 167 patients with primary or secondary antibody deficiencies on immunoglobulin (Ig)-replacement treatment. The demographics, causes of immunodeficiency, diagnostic delay, clinical and laboratory features, and infection frequency were analysed retrospectively. Chemotherapy for B cell lymphoma and the use of Rituximab, corticosteroids or immunosuppressive medications were the most common causes of secondary antibody deficiency in this cohort. There was no difference in diagnostic delay or bronchiectasis between primary and secondary antibody deficiency patients, and both groups experienced disorders associated with immune dysregulation. Secondary antibody deficiency patients had similar baseline levels of serum IgG, but higher IgM and IgA, and a higher frequency of switched memory B cells than primary antibody deficiency patients. Serious and non-serious infections before and after Ig-replacement were also compared in both groups. Although secondary antibody deficiency patients had more serious infections before initiation of Ig-replacement, treatment resulted in a significant reduction of serious and non-serious infections in both primary and secondary antibody deficiency patients. Patients with secondary antibody deficiency experience similar delays in diagnosis as primary antibody deficiency patients and can also benefit from immunoglobulin-replacement treatment.</p></div

    Experimental Bounds on Masses and Fluxes of Nontopological Solitons

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    We have re-analyzed the results of various experiments which were not originally interested as searches for the Q-ball or the Fermi-ball. Based on these analyses, in addition to the available data on Q-balls, we obtained rather stringent bounds on flux, mass and typical energy scale of Q-balls as well as Fermi-balls. In case these nontopological solitons are the main component of the dark matter of the Galaxy, we found that only such solitons with very large quantum numbers are allowed. We also estimate how sensitive future experiments will be in the search for Q-balls and Fermi-balls.Comment: 19 pages, 7 eps figures, RevTeX, psfig.st

    Preliminary archaeoentomological analyses of permafrost-preserved cultural layers from the pre-contact Yup’ik Eskimo site of Nunalleq, Alaska : implications, potential and methodological considerations

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    Acknowledgements Site excavation and samples collection were conducted by archaeologists from the University of Aberdeen, with the help of archaeologists and student excavators from the University of Aberdeen University of Alaska Fairbanks and Bryn Mawr College, Kuskokwim Campus, College of Rural Alaska and residents of Quinhagak and Mekoryuk. This study is funded through AHRC grant to the project ‘Understanding Cultural Resilience and Climate Change on the Bering Sea through Yup’ik Ecological Knowledge, Lifeways, Learning and Archaeology’ to Rick Knecht, Kate Britton and Charlotta Hillderal (University of Aberdeen; AH/K006029/1). Thanks are due to Qanirtuuq Inc. and Quinhagak, Alaska for sampling permissions and to entomologists working at the CNC in Ottawa for allowing access to reference collections of beetles, lice and fleas. Yves Bousquet, Ales Smetana and Anthony E. Davies are specially acknowledged for their help with the identification of coleopteran specimens. Finally, we would also like to thank Scott Elias for useful comments on the original manuscript.Peer reviewedPublisher PD

    Are bisphosphonates effective in the treatment of osteoarthritis pain? A meta-analysis and systematic review.

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    Osteoarthritis (OA) is the most common form of arthritis worldwide. Pain and reduced function are the main symptoms in this prevalent disease. There are currently no treatments for OA that modify disease progression; therefore analgesic drugs and joint replacement for larger joints are the standard of care. In light of several recent studies reporting the use of bisphosphonates for OA treatment, our work aimed to evaluate published literature to assess the effectiveness of bisphosphonates in OA treatment

    Smash and Bash Cricket? Affective Technological Innovations in the Big Bash

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    Focusing on the Australian KFC T20 Big Bash League (BBL), this article explores the innovative televisual technologies that represent T20 cricket as an action packed 'smash and bash' spectacle. An array of innovative technologies is deployed to aesthetically and affectively re-present the BBL. Cameras and microphones are embedded within the field of play, operate in highly mobile and fluid ways, and are framed in close proximity to the action - particularly when placed on the players themselves. The BBL provides intersecting affective layers for viewer engagement built upon tools for analysis, sites of commodification, visual renditions of pseudo-player perspectives and an emphasis on fast-paced entertainment. By constructing degrees of sensory invigoration and vicarious involvement for both casual and invested viewers, these innovative technologies mobilise 'smash and bash' cricket as an affective televisual spectacle
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