216 research outputs found

    Coupling virtual watersheds with ecosystem services assessment: A 21st century platform to support river research and management

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    The demand for freshwater is projected to increase worldwide over the coming decades, resulting in severe water stress and threats to riverine biodiversity, ecosystem functioning and services. A major societal challenge is to determine where environmental changes will have the greatest impacts on riverine ecosystem services and where resilience can be incorporated into adaptive resource planning. Both water managers and scientists need new integrative tools to guide them towards the best solutions that meet the demands of a growing human population but also ensure riverine biodiversity and ecosystem integrity. Resource planners and scientists could better address a growing set of riverine management and risk mitigation issues by (1) using a “Virtual Watersheds” approach based on improved digital river networks and better connections to terrestrial systems; (2) integrating Virtual Watersheds with ecosystem services technology (ARtificial Intelligence for Ecosystem Services: ARIES), and (3) incorporating the role of riverine biotic interactions in shaping ecological responses. This integrative platform can support both interdisciplinary scientific analyses of pressing societal issues and effective dissemination of findings across river research and management communities. It should also provide new integrative tools to identify the best solutions and trade-offs to ensure the conservation of riverine biodiversity and ecosystem services

    Seroprevalence of Toxoplasma gondii and Neospora spp. Infections in Arab Horses, Southwest of Iran

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    Background: Because of the economic importance of the Arab race horses and also the role of Toxoplasma gondii and Neospora spp. in abortion and reproductive failure of these animals, we decided to perform this study. Objectives: We designed this study to investigate the seroprevalence of anti-Toxoplasma gondii and anti-Neospora spp. antibodies in Arab horses from 12 cities of Khuzestan province in southwest of Iran. Materials and Methods: From October 2009 to March 2011, a total of 235 blood samples were collected from jugular veins of Arab horses of different ages and genders from 12 cities of Khuzestan province. All the sera were tested for anti-Toxoplasma antibodies using the modified agglutination test (MAT) and the existence of anti-Neospora antibodies were tested using N-MAT for Neospora spp. Results: According to the MAT results, antibodies to T. gondii were found in 114 (48.5%) of 235 sera with titers of 1:20 in 84, 1:40 in 19, 1:80 in four, 1:160 in four, and 1:320 in three horses. According to the N-MAT results, antibodies to Neospora spp. were found in 47 (20%) of 235 sera with titers of 1:40 in 39, 1:80 in five, and 1:160 in three horses. We did not observe any statistically significant differences regarding age groups and genders between seropositive and seronegative horses for Neospora spp. using chi-square (chi(2)) test, but it seemed that anti-Toxoplasma antibodies were more prevalent in older horses ( >= 10 years old). Conclusions: The results indicated that Arab horses are exposed to these parasites in southwest of Iran. Further research is required to determine the genomic structures of these parasites in Arab horses in southwest of Iran

    Accidental Inflation in String Theory

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    We show that inflation in type IIB string theory driven by the volume modulus can be realized in the context of the racetrack-based Kallosh-Linde model (KL) of moduli stabilization. Inflation here arises through the volume modulus slow-rolling down from a flat hill-top or inflection point of the scalar potential. This situation can be quite generic in the landscape, where by uplifting one of the two adjacent minima one can turn the barrier either to a flat saddle point or to an inflection point supporting eternal inflation. The resulting spectral index is tunable in the range of 0.93 < n_s < 1, and there is only negligible production of primordial gravitational waves r < 10^{-6}. The flatness of the potential in this scenario requires fine-tuning, which may be justified taking into account the exponential reward by volume factors preferring the regions of the universe with the maximal amount of slow-roll inflation. This consideration leads to a tentative prediction of the spectral index ns0.95n_s\approx 0.95 or ns0.93n_s \approx 0.93 depending on whether the potential has a symmetry phi -> - phi or not.Comment: 15 pages, 6 figures, LaTeX, uses RevTex

    Lectures on Cosmic Inflation and its Potential Stringy Realizations

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    These notes present a brief introduction to Hot Big Bang cosmology and Cosmic Inflation, together with a selection of some recent attempts to embed inflation into string theory. They provide a partial description of lectures presented in courses at Dubrovnik in August 2006, at CERN in January 2007 and at Cargese in August 2007. They are aimed at graduate students with a working knowledge of quantum field theory, but who are unfamiliar with the details of cosmology or of string theory.Comment: 68 pages, lectures given at Dubrovnik, Aug 2006; CERN, January 2007; and Cargese, Aug 200

    Successful surgical excision of primary right atrial angiosarcoma

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    Primary cardiac angiosarcoma is a rare and aggressive tumor with a high incidence of metastatic spread (up to 89%) at the time of diagnosis, which restricts the indication for surgical resection to a small number of patients. We report the case of a 50-year old Caucasian woman with non-metastatic primary right atrial angiosarcoma, who underwent successful surgical excision of the tumor (with curative intent) and reconstruction of the right atrium with a porcine pericardial patch. However, after a symptom-free survival of five months the patient presented with bone and liver metastases without evidence of local tumor recurrence

    Errors in Judicial Decisions

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    In criminal cases the task of the judge is to transform the uncertainty about the facts into the certainty of the verdict. In this experiment we examine the relationship between evidence of which the strength is known, subjective probability of guilt and verdict for abstract cases. We look at two situations: (1) all evidence is given and (2) evidence can be acquired. Roughly half of the participants do not base their decision on a subjective belief of the probability of guilt. The others underestimate in general the probability of guilt, but this is more than compensated by a tendency to convict at too low probability of guilt. In the situation where evidence can be acquired, participants do not acquire enough evidence

    Facilitating arrhythmia simulation: the method of quantitative cellular automata modeling and parallel running

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    BACKGROUND: Many arrhythmias are triggered by abnormal electrical activity at the ionic channel and cell level, and then evolve spatio-temporally within the heart. To understand arrhythmias better and to diagnose them more precisely by their ECG waveforms, a whole-heart model is required to explore the association between the massively parallel activities at the channel/cell level and the integrative electrophysiological phenomena at organ level. METHODS: We have developed a method to build large-scale electrophysiological models by using extended cellular automata, and to run such models on a cluster of shared memory machines. We describe here the method, including the extension of a language-based cellular automaton to implement quantitative computing, the building of a whole-heart model with Visible Human Project data, the parallelization of the model on a cluster of shared memory computers with OpenMP and MPI hybrid programming, and a simulation algorithm that links cellular activity with the ECG. RESULTS: We demonstrate that electrical activities at channel, cell, and organ levels can be traced and captured conveniently in our extended cellular automaton system. Examples of some ECG waveforms simulated with a 2-D slice are given to support the ECG simulation algorithm. A performance evaluation of the 3-D model on a four-node cluster is also given. CONCLUSIONS: Quantitative multicellular modeling with extended cellular automata is a highly efficient and widely applicable method to weave experimental data at different levels into computational models. This process can be used to investigate complex and collective biological activities that can be described neither by their governing differentiation equations nor by discrete parallel computation. Transparent cluster computing is a convenient and effective method to make time-consuming simulation feasible. Arrhythmias, as a typical case, can be effectively simulated with the methods described

    Robust physical methods that enrich genomic regions identical by descent for linkage studies: confirmation of a locus for osteogenesis imperfecta

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    <p>Abstract</p> <p>Background</p> <p>The monogenic disease osteogenesis imperfecta (OI) is due to single mutations in either of the collagen genes ColA1 or ColA2, but within the same family a given mutation is accompanied by a wide range of disease severity. Although this phenotypic variability implies the existence of modifier gene variants, genome wide scanning of DNA from OI patients has not been reported. Promising genome wide marker-independent physical methods for identifying disease-related loci have lacked robustness for widespread applicability. Therefore we sought to improve these methods and demonstrate their performance to identify known and novel loci relevant to OI.</p> <p>Results</p> <p>We have improved methods for enriching regions of identity-by-descent (IBD) shared between related, afflicted individuals. The extent of enrichment exceeds 10- to 50-fold for some loci. The efficiency of the new process is shown by confirmation of the identification of the Col1A2 locus in osteogenesis imperfecta patients from Amish families. Moreover the analysis revealed additional candidate linkage loci that may harbour modifier genes for OI; a locus on chromosome 1q includes COX-2, a gene implicated in osteogenesis.</p> <p>Conclusion</p> <p>Technology for physical enrichment of IBD loci is now robust and applicable for finding genes for monogenic diseases and genes for complex diseases. The data support the further investigation of genetic loci other than collagen gene loci to identify genes affecting the clinical expression of osteogenesis imperfecta. The discrimination of IBD mapping will be enhanced when the IBD enrichment procedure is coupled with deep resequencing.</p
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