3,035 research outputs found

    The Forum of European Geological Surveys Geochemistry Task Group 1994-1996 inventory

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    The Forum of European Geological Surveys (FOREGS) includes representatives from 33 European countries and is responsible for co-ordinating Geological Survey activities in Europe. The FOREGS Geochemistry Task Group was established in 1994 to develop a strategy for the preparation of European geochemical maps following the recommendations of the International Geological Correlation Programme (IGCP) Project 259 ā€˜International Geochemical Mappingā€™ (now the International Union of Geological Sciences (IUGS) /International Association of Geochemistry and Cosmochemistry (IAGC) Working Group on Global Geochemical Baselines). The FOREGS geochemistry programme is aimed at preparing a standardised European geochemical baseline to IGCP-259 standards. The principal aims of this dataset will be for environmental purposes, as a baseline for the assessment of the extent and distribution of contaminated land in the context of variations in the natural geochemical background, but it will also have applications in resource assessment and for the development of policy for the sustainable management of metalliferous mineral and other resources. The first phase of the programme was the compilation of an inventory of geochemical data based on the results of a questionnaire completed by Geological Surveys and related organisations throughout the FOREGS community. The results show that the sample types which have been used most extensively are stream sediment (26% coverage), surface water (19% coverage) and soil (11% coverage). Stream sediments have been collected using a narrow range of mesh sizes (< 150ā€“< 200 Ī¼m), but soil samples have been collected according to two different conventions: some surveys used a similar mesh size range to that used for stream sediments while others employed the < 1000 or < 2000 Ī¼m fractions traditionally used by soil surveys. Sample densities range from 1 sample per 0.5 km2 to 1 per 3500 km2. Various analytical methods have been used, but most of the available data have been calibrated using international reference materials, and data for the most important of the potentially harmful elements (PHEs) are available for most datasets. Systematic radiometric data are available for only a small proportion of Europe, a situation which compares very unfavourably with that in Australia, North America, the former Soviet Union and many developing countries. Recommendations are made for increasing the compatibility of geochemical methods between national geochemical surveys as a basis for the preparation of a series of European geochemical maps. The next stage of the FOREGS Geochemistry Task Group will be the collection of the Global Reference Network of samples against which to standardise national datasets according to the methods recommended in the final report of the IGCP 259 programme

    Chronic wasting disease detection and mortality sources in semi-protected deer population

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    Surveillance for wildlife diseases is essential for assessing population dynamics of ungulates, especially in free-ranging populations where infected animals are difficult to sample. Chronic wasting disease (CWD) is an emerging infectious disease of concern because of the potential for substantial negative effects on populations of cervids. Variability in the likelihood that CWD is detected could invalidate traditional estimators for prevalence. In some instances, deer located after death cannot be tested for infectious diseases, including CWD, because of lack of availability or condition of appropriate tissues. We used various methods to detect infectious diseases that could cause mortality for deer Odocoileus spp. residing in Wind Cave National Park, South Dakota, USA, and we report survival estimates for animals in this population. We included 34 monthly encounters of deer resightings and 67 mortalities. We tested live deer by tonsillar biopsy for CWD and estimated pooled prevalence (mean Ā± SE) at 5.6 Ā± 3.0% over the three-year study. Live deer potentially had exposure to several infectious diseases, including bluetongue, epizootic hemorrhagic disease, bovine viral diarrhea, West Nile virus, and malignant catarrhal fever, but no apparent morbidity or mortality from those diseases. We tested survival and influence of covariates, including age and sex, using known-fate analysis in Program MARK. Those data best supported a model with time-invariant encounter probability and an annual survival of 72.8%. Even without direct pressure from hunting within the park, average life expectancy in this population was 3.2 years. Only 68% of mortalities contained sufficient material for CWD sampling (because of predation and scavenger activity) and \u3e42% of these were CWD-positive. These findings underscore the possible biases in postmortem surveillance estimates of disease prevalence because of potential for subclinical infected animals to be removed by predators and not tested

    Subslab mantle of African provenance infiltrating the Aegean mantle wedge

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    The presence of a tear in the subducting African slab has a strong effect on Neogene magmatism in western Turkey, but its influence on volcanism in the Quaternary Aegean arc to the west is unknown. In order to investigate to what extent arc volcanism can be affected by slab-parallel mantle flow from a slab window, we present new trace element and Nd-Pb isotope data for Nisyros and Santorini volcanoes. Trace element modeling allows quantification of the infiltration of trace element-enriched mantle of subslab provenance through the slab tear into the depleted Aegean mantle wedge. Primitive Nisyros magmas record melting of a mixed source that contains as much as 10% of the enriched, subslab mantle component, and a contribution of this component can be traced as far west as Santorini, ~250 km away from the slab tear. We conclude that trace element and Nd-Pb isotope variations between Nisyros and Santorini do not require along-arc variations in subducting sediment composition, but reflect the heterogeneous nature of the Aegean mantle wedge related to infiltration of subslab mantle through the slab tear. Our geochemical evidence is in excellent agreement with predictions made on the basis of mantle tomography and anisotropy that indicate toroidal mantle flow around the edge of the Aegean slab. This implies that suction related to slab rollback can lead to the infiltration of subslab mantle material and slab-parallel mantle flow, thus potentially strongly influencing arc volcanism, processes that perhaps need greater assessment in other arc systems

    Empowering patients with high myopia:The significance of education

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    Purpose:Ā To investigate the status of patient education among highly myopic individuals focusing on the presence, sources, content, timing of the education and impact on patients.Ā Methods:Ā Self-reported data were collected through an online 13-item questionnaire consisting of open and multiple-choice questions. The questionnaire was sent to 250 highly myopic members of a patient organization in the Netherlands, of whom 128 (51%) responded.Ā Results:Ā At least one acute event had occurred in 66% (84/128) of participants at the time of the questionnaire. Among all participants, 25% (32/128) had not received patient education regarding alarm symptoms for any of these events. Among those who had been informed, the ophthalmologist was the most frequent (57%, 73/128) source of information. Participants who visited the ophthalmologist annually were more frequently informed than participants without annual visits (53%, 26/49 versus 26%, 9/35, p = 0.002). Those not informed were more likely to have a more than 3 days patient delay (92%, 12/13). Doctors delay was also present; 26% (22/84) of the participants with alarm symptoms had to wait 2 or more days before the first appointment. Long-term consequences of myopia had been discussed with 102 participants (80%, 102/128), again with the ophthalmologist as the most frequent source (59%, 76/128).Ā Perspectives:Ā Many myopic individuals have not been educated about their increased risk of acute events, which can result in patient delay and serious consequences with respect to visual prognosis. These findings underscore the critical importance of integrating patient education across the entire ophthalmic care chain for myopia.</p

    A Method of Drusen Measurement Based on the Geometry of Fundus Reflectance

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    BACKGROUND: The hallmarks of age-related macular degeneration, the leading cause of blindness in the developed world, are the subretinal deposits known as drusen. Drusen identification and measurement play a key role in clinical studies of this disease. Current manual methods of drusen measurement are laborious and subjective. Our purpose was to expedite clinical research with an accurate, reliable digital method. METHODS: An interactive semi-automated procedure was developed to level the macular background reflectance for the purpose of morphometric analysis of drusen. 12 color fundus photographs of patients with age-related macular degeneration and drusen were analyzed. After digitizing the photographs, the underlying background pattern in the green channel was leveled by an algorithm based on the elliptically concentric geometry of the reflectance in the normal macula: the gray scale values of all structures within defined elliptical boundaries were raised sequentially until a uniform background was obtained. Segmentation of drusen and area measurements in the central and middle subfields (1000 Ī¼m and 3000 Ī¼m diameters) were performed by uniform thresholds. Two observers using this interactive semi-automated software measured each image digitally. The mean digital measurements were compared to independent stereo fundus gradings by two expert graders (stereo Grader 1 estimated the drusen percentage in each of the 24 regions as falling into one of four standard broad ranges; stereo Grader 2 estimated drusen percentages in 1% to 5% intervals). RESULTS: The mean digital area measurements had a median standard deviation of 1.9%. The mean digital area measurements agreed with stereo Grader 1 in 22/24 cases. The 95% limits of agreement between the mean digital area measurements and the more precise stereo gradings of Grader 2 were -6.4 % to +6.8 % in the central subfield and -6.0 % to +4.5 % in the middle subfield. The mean absolute differences between the digital and stereo gradings 2 were 2.8 +/- 3.4% in the central subfield and 2.2 +/- 2.7% in the middle subfield. CONCLUSIONS: Semi-automated, supervised drusen measurements may be done reproducibly and accurately with adaptations of commercial software. This technique for macular image analysis has potential for use in clinical research

    Evaluating Genetic Viability of Pronghorn in Wind Cave National Park

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    The pronghorn (Antilocapra americana) was reintroduced into Wind Cave National Park, South Dakota, in 1914 and thus, has inhabited the Park for almost a century. A decline in the population has raised concern for the continued existence of pronghorn inside Wind Cave National Park. Historically, pronghorn numbers reached greater than 300 individuals in the 1960\u27s but declined to about 30 individuals by 2002. The primary objective of our study was to evaluate genetic characteristics of pronghorn to determine if reduced heterozygosity contributed to the decline of pronghorn in Wind Cave National Park. Microsatellite DNA was collected from 75 pronghorn inhabiting Wind Cave National Park in western South Dakota (n = 11), northwestern South Dakota (n = 33), and southwestern South Dakota (n = 31). Pronghorn in Wind Cave National Park had similar levels of observed heterozygosity (0.473 to 0.594) and low inbreeding coefficients (-0.168 to 0.037) when compared with other populations in western South Dakota. Furthermore, indices of population structure indicated no differentiation occurred among pronghorn populations. Results indicated that genetic variability was not a primary factor in the decline of pronghorn in Wind Cave National Park

    Clinical characterization of 66 patients with congenital retinal disease due to the deep-intronic c.2991+1655A>G mutation in CEP290

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    Purpose: To describe the phenotypic spectrum of retinal disease caused by the c.2991+1655A>G mutation in CEP290 and to compare disease severity between homozygous and compound heterozygous patients. Methods: Medical records were reviewed for best-corrected visual acuity (BCVA), age of onset, fundoscopy descriptions. Foveal outer nuclear layer (ONL) and ellipsoid zone (EZ) presence was assessed using spectral-domain optical coherence tomography (SD-OCT). Differences between compound heterozygous and homozygous patients were analyzed based on visual performance and visual development. Results: A total of 66 patients were included. The majority of patients had either light perception or no light perception. In the remaining group of 14 patients, median BCVA was 20/195 Snellen (0.99 LogMAR; range 0.12-1.90) for the right eye, and 20/148 Snellen (0.87 LogMAR; range 0.22-1.90) for the left. Homozygous patients tended to be more likely to develop light perception compared to more severely affected compound heterozygous patients (P = 0.080) and are more likely to improve from no light perception to light perception (P = 0.022) before the age of 6 years. OCT data were available in 12 patients, 11 of whom had retained foveal ONL and EZ integrity up to 48 years (median 23 years) of age. Conclusions: Homozygous patients seem less severely affected compared to their compound-heterozygous peers. Improvement of visual function may occur in the early years of life, suggesting a time window for therapeutic intervention up to the approximate age of 17 years. This period may be extended by an intact foveal ONL and EZ on OCT

    Frauds, strategies and complaints in Germany

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    Many statistical methods that use low-level election vote count data to detect election frauds have the limitation that they have a hard time distinguishing distortions in vote counts that stem from votersā€™ strategic behavior from distortions that originate with election frauds. Identifying latent components that underlie election forensics statistics and other contextual variables can help show the extent to which the statistics measure fraudulent as opposed to strategic behavior. We use an active-learning procedure with a support vector machine to classify complaints about German federal elections during 1949ā€“2009 to show the diversity of the complaints, which we use as contextual data. We also use variables that measure strategic voting in those elections. For the elections of 2005 and 2009 we use latent variable methods to assess whether the parameters of a positive empirical model of frauds connect through latent variable structure to either the complaints or the strategic variables. Geographic ambiguity about the locations at which some complaints occur motivates embedding a geographic mixture structure in the latent variable model. The ā€œfraudā€ parameters connect to both complaints and strategic behavior
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