73 research outputs found

    Paleotopographic evolution of the brazilian continental margin during the Phanerozoic: evidence from apatite fission track thermochronology

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    Este trabalho explora banco de dados traços de fissão em apatitas com o objetivo de desenvolver uma visão sinóptica de padrões de denudação através do espaço-tempo na margem continental brasileira. A resposta geomorfológica aos processos de rifteamento e ruptura continental variou ao longo da margem continental brasileira. No processo de construção do relevo desta margem foram registrados três episódios de resfriamento acelerado, que são vinculados a processos denudacionais: Cretáceo Inferior, Cretáceo Superior e Paleógeno-Neógeno. As margens continentais sudeste e leste apresentam uma morfologia de margem continental passiva característica, com as bacias sedimentares offshore separadas da região continental elevada, composta pelas Serra do Mar e daSerra da Mantiqueira, por uma planície costeira relativamente estreita. As idades de soerguimento são mais jovens do que a idade do rifteamento. O resfriamento do Paleógeno-Neógeno é resultado do aumento nas taxas de denudação, que são relacionados à formação e reativação de blocos de falha de alto ângulo que se moveram em resposta às tensões intraplaca. A região do Arco de Ponta Grossa apresenta o relevo mais jovem de toda a margem, sendo um alto topográfico associado ao magmatismo Paraná-Etendeka e limitado por zonas de cisalhamento. Duas porções da margem apresentam relevo diferenciado, com episódios de denudação pré-rifte. A Depressão Sertaneja, na margem nordeste, típica região semi-árida do nordeste caracterizada como um pediplano, com vales estreitos e vertentes dissecadas, com resfriamento do Permiano-Jurássico Inferior; e a margem sul, local com topografia baixa, e soerguimento lento e contínuo do Paleozoico.This study explores apatite fission track database with the objective of developing a synoptic view of denudation patterns across space and time in the Brazilian continental margin. The geomorphological response to the continental rift and rupture processes varied along the Brazilian continental margin. In the construction of the relief of this margin were recorded three episodes of accelerated cooling, which are linked to denudational processes: Lower Cretaceous, Upper Cretaceous and Paleogene-Neogene episodes. The southeast and eastern continental margin presents a characteristic passive continental margin morphology, with the offshore sedimentary basins separated from the elevated continental region, Serra do Mar and Serra da Mantiqueira, for a relatively narrow coastal plain. The uplifting ages are younger than the rift age. Accelerated cooling during Paleogene-Neogene is a result of increased denudation rates, which are related to the formation and reactivation of high angle fault blocks that have moved in response to intraplate stresses. The region of the Ponta Grossa Arch presents the youngest relief of the entire continental margin. It is a high topographic associated with Paraná-Etendeka magmatism and limited by shear zones. There are two parts of the continental margin with differentiated relief, which present episodes of pre-rift denudation. The Sertaneja Depression, in the northeast margin, a typical semi-arid northeast region characterized as a pediplane, with narrow valleys and dissected slopes, where occurs a Permian-Lower Jurassic cooling episode; and the south continental margin, where the topography is relatively, registering a slow and continuous uplift during the Paleozoic

    Unexpected Test Results in a Patient with Multiple Myeloma

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    A 53-year-old male patient with an established diagnosis of IgG λ multiple myeloma was seen by a hematologist–oncologist in consultation from an outside hospital. He had previously received 1 cycle of chemotherapy treatment, but he was found to be intermittently noncompliant with his therapy. The patient reported occasional nosebleeds and fatigue. Except for a slightly cachectic appearance, the physical examination was unremarkable. Chemistry and hematology laboratory results are shown in Table 1. Serum protein electrophoresis revealed monoclonal paraproteinemia in high abundance marked by an intense band in the γ region. Immunofixation electrophoresis was not ordered at that time, but it was previously performed at another institution and was positive for IgG monoclonal protein. The attending pathologist noted the discrepancy between the presence of a monoclonal band by serum protein electrophoresis and the patient\u27s quantitative immunoglobulin measurements. Several additional suspicious test results were also noted

    Thermochronology of South America passive margin between Uruguay and southern Brazil : A lengthy and complex cooling history based on (U–Th)/ He and fission tracks

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    The authors gratefully acknowledge the support from Shell Brasil through the “BG05: UoA-UFRGS-SWB Sedimentary Systems” project at UFRGS and UoA, and the strategic importance of the support given by ANP through the R&D levy regulation. J.P. Machado thanks the CNPq (SWE 204254/2017–5) for the exchange period at the University of Aberdeen, and A.R. Jelinek also thanks the support from CNPq (Project 303184/2017–5). We are grateful for the helpful and constructive reviews from Mathias Hueck, Mauricio Parra and an anonymous reviewer, that greatly improved this manuscript.Peer reviewedPostprin

    Low-temperature thermochronology of the South Atlantic margin along Uruguay and its relation to tectonic events in West Gondwana

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    The authors gratefully acknowledge the support from Shell Brasil through the “Shell - BG05: UoA-UFRGS-SWB Sedimentary Systems” project at UFRGS and the strategic importance of the support given by ANP through the R&D levy regulation. We thank Peter Reiners and his team at the Arizona Radiogenic Helium Dating Laboratory (US) for the (UTh)/He analyses and support during the data evaluation. The first author thanks the CNPq scholarship (SWE 204254/2017-5) during the exchange period at the University of Aberdeen. A.R. Jelinek also thanks the support from CNPq (Project 303184/2017-5). This manuscript was improved after helpful reviews by Mathias Hueck and an anonymous reviewer.Peer reviewedPostprin

    Headaches and hemiparesis in an immunocompetent inmate

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    This is a case of a 22 year-old African American male inmate with no significant past medical history who regularly cleaned moldy bathrooms and showers during his incarceration. The patient presented with progressive development of left-sided weakness, dizziness, headaches, and vomiting over a two month period. In summary, we report this case to boost awareness of the potential for CNS phaeohyphomycosis infection to present as a clinical and radioimaging mimic of high grade glioma. Our patient, a previously healthy adult, is one of less than a dozen cases of cerebral phaeohyphomycosis due to Bipolaris documented in the literature, and is only the second patient to present with imaging features very suggestive of high grade infiltrative glioma

    Applying multidimensional computerized adaptive testing to the MSQOL-54: a simulation study

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    Background: The Multiple Sclerosis Quality of Life-54 (MSQOL-54) is one of the most commonly-used MS-specific health-related quality of life (HRQOL) measures. It is a multidimensional, MS-specific HRQOL inventory, which includes the generic SF-36 core items, supplemented with 18 MS-targeted items. Availability of an adaptive short version providing immediate item scoring may improve instrument usability and validity. However, multidimensional computerized adaptive testing (MCAT) has not been previously applied to MSQOL-54 items. We thus aimed to apply MCAT to the MSQOL-54 and assess its performance. Methods: Responses from a large international sample of 3669 MS patients were assessed. We calibrated 52 (of the 54) items using bifactor graded response model (10 group factors and one general HRQOL factor). Then, eight simulations were run with different termination criteria: standard errors (SE) for the general factor and group factors set to different values, and change in factor estimates from one item to the next set at < 0.01 for both the general and the group factors. Performance of the MCAT was assessed by the number of administered items, root mean square difference (RMSD), and correlation. Results: Eight items were removed due to local dependency. The simulation with SE set to 0.32 (general factor), and no SE thresholds (group factors) provided satisfactory performance: the median number of administered items was 24, RMSD was 0.32, and correlation was 0.94. Conclusions: Compared to the full-length MSQOL-54, the simulated MCAT required fewer items without losing precision for the general HRQOL factor. Further work is needed to add/integrate/revise MSQOL-54 items in order to make the calibration and MCAT performance efficient also on group factors, so that the MCAT version may be used in clinical practice and research

    Viability of a MSQOL-54 general health-related quality of life score using bifactor model

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    Background MSQOL-54 is a multidimensional, widely-used, health-related quality of life (HRQOL) instrument specific for multiple sclerosis (MS). Findings from the validation study suggested that the two MSQOL-54 composite scores are correlated. Given this correlation, it could be assumed that a unique total score of HRQOL may be calculated, with the advantage to provide key stakeholders with a single overall HRQOL score. We aimed to assess how well the bifactor model could account for the MSQOL-54 structure, in order to verify whether a total HRQOL score can be calculated. Methods A large international database (3669 MS patients) was used. By means of confirmatory factor analysis, we estimated a bifactor model in which every item loads onto both a general factor and a group factor. Fit of the bifactor model was compared to that of single and two second-order factor models by means of Akaike information and Bayesian information criteria reduction. Reliability of the total and subscale scores was evaluated with Mc Donald's coefficients (omega, and omega hierarchical). Results The bifactor model outperformed the two second-order factor models in all the statistics. All items loaded satisfactorily (>= 0.40) on the general HRQOL factor, except the sexual function items. Omega coefficients for total score were very satisfactory (0.98 and 0.87). Omega hierarchical for subscales ranged between 0.22 to 0.57, except for the sexual function (0.70). Conclusions The bifactor model is particularly useful when it is intended to acknowledge multidimensionality and at the same time take account of a single general construct, as the HRQOL related to MS. The total raw score can be used as an estimate of the general HRQOL latent score

    Dietary responses to a multiple sclerosis diagnosis: a qualitative study

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    Background/objectives: Multiple sclerosis (MS) is an immune-mediated disease with no known cure and insufficient evidence to support a special therapeutic diet to alter symptom management or disease progression. Several studies have reported dietary changes made by people with MS, but there has been limited investigation into experiences surrounding diet in those recently diagnosed. This study explored responses to diet after a recent diagnosis of MS in people living in Western Australia. Subjects/methods: Eleven adults with MS (mean time since diagnosis 8 months) participated in semi-structured interviews focusing on responses to diet since MS diagnosis. Interviews were transcribed, coded and analysed using grounded theory principles. Results: Three theme responses emerged; (1) the perceived incompatibility of lack of/or generalised dietary advice with disease seriousness at the time of diagnosis; (2) extensive personal research and information seeking with difficulty judging credibility, and (3) self-experimentation with diet to either control MS symptoms or to cure MS. Conclusions: Given the seriousness of the disease, there is a perceived gap in dietary information provided at the time of diagnosis. Healthcare professionals should address concerns with alternative therapeutic diets advertised to treat or cure MS, and clearly convey the reasoning for the general healthy dietary recommendations. This would better align advice with the perceptions about the role of diet in MS, assist people with MS in need of information and minimise dietary self-experimentation. Future research should explore the importance of diet for those who have had MS for a longer period of time

    TLR3 essentially promotes protective class I–restricted memory CD8+ T-cell responses to Aspergillus fumigatus in hematopoietic transplanted patients

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    Aspergillus fumigatus is a model fungal pathogen and a common cause of severe infections and diseases. CD8+ T cells are present in the human and murine T-cell repertoire to the fungus. However, CD8+ T-cell function in infection and the molecular mechanisms that control their priming and differentiation into effector and memory cells in vivo remain elusive. In the present study, we report that both CD4+ and CD8+ T cells mediate protective memory responses to the fungus contingent on the nature of the fungal vaccine. Mechanistically, class I MHC-restricted, CD8+ memory T cells were activated through TLR3 sensing of fungal RNA by cross-presenting dendritic cells. Genetic deficiency of TLR3 was associated with susceptibility to aspergillosis and concomitant failure to activate memory-protective CD8+ T cells both in mice and in patients receiving stem-cell transplantations. Therefore, TLR3 essentially promotes antifungal memory CD8+ T-cell responses and its deficiency is a novel susceptibility factor for aspergillosis in high-risk patients.These studies were supported by the Specific Targeted Research Project ALLFUN (FP7-HEALTH-2009 contract number 260338 to L.R.), by SYBARIS (FP7-HEALTH-2009 contract number 242220 to L.R.), and by the Italian Project AIDS 2010 by the Istituto Superiore di Sanita (contract number 40H40 to L.R.). A.C. and C.C. were supported by fellowships from Fundacao para a Ciencia e Tecnologia, Portugal (contracts SFRH/BPD/46292/2008 and SFRH/BD/65962/2009, respectively)

    Anisotropy of magnetic susceptibility in alkali feldspar and plagioclase

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    Feldspars are the most abundant rock-forming minerals in the Earth’s crust, but their magnetic properties have not been rigorously studied. This work focuses on the intrinsic magnetic anisotropy of 31 feldspar samples with various chemical compositions. Because feldspar is often twinned or shows exsolution textures, measurements were performed on twinned and exsolved samples as well as single crystals. The anisotropy is controlled by the diamagnetic susceptibility and displays a consistent orientation of principal susceptibility axes; the most negative or minimum susceptibility is parallel to [010], and the maximum (least negative) is close to the crystallographic [001] axis. However, the magnetic anisotropy is weak when compared to other rock-forming minerals, 1.53 × 10−9 m3 kg−1 at maximum. Therefore, lower abundance minerals, such as augite, hornblende or biotite, often dominate the bulk paramagnetic anisotropy of a rock. Ferromagnetic anisotropy is not significant in most samples. In the few samples that do show ferromagnetic anisotropy, the principal susceptibility directions of the ferromagnetic subfabric do not display a systematic orientation with respect to the feldspar lattice. These results suggest that palaeointensity estimates of the geomagnetic field made on single crystals of feldspar will not be affected by a systematic orientation of the ferromagnetic inclusions within the feldspar lattice
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