141 research outputs found

    Geometrical effects on axial & azimuthal variations of heat flux to coolant in asymmetrically heated channels

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    "July 1998."This report summarizes analyses of the effects of heat conduction in a copper block on the heat flux to a coolant flowing axially in the block. Heat is assumed to be added through one side of the block corresponding to conditions that may arise in fusion reactors or particle accelerator targets. It is found that three dimensional analysis of the heat transport will be required to accurately describe the heat flux at the wall of the coolant channel. The effects of axial and azimuthal heat conduction in the copper block depend on the block width to channel diameter ratio and the BIOT number of the channel

    Oxidation of manganese in an ancient aquifer, Kimberley formation, Gale crater, Mars

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    The Curiosity rover observed high Mn abundances (>25 wt % MnO) in fracture‐filling materials that crosscut sandstones in the Kimberley region of Gale crater, Mars. The correlation between Mn and trace metal abundances plus the lack of correlation between Mn and elements such as S, Cl, and C, reveals that these deposits are Mn oxides rather than evaporites or other salts. On Earth, environments that concentrate Mn and deposit Mn minerals require water and highly oxidizing conditions; hence, these findings suggest that similar processes occurred on Mars. Based on the strong association between Mn‐oxide deposition and evolving atmospheric dioxygen levels on Earth, the presence of these Mn phases on Mars suggests that there was more abundant molecular oxygen within the atmosphere and some groundwaters of ancient Mars than in the present day

    Deep Spectral CNN for Laser Induced Breakdown Spectroscopy

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    This work proposes a spectral convolutional neural network (CNN) operating on laser induced breakdown spectroscopy (LIBS) signals to learn to (1) disentangle spectral signals from the sources of sensor uncertainty (i.e., pre-process) and (2) get qualitative and quantitative measures of chemical content of a sample given a spectral signal (i.e., calibrate). Once the spectral CNN is trained, it can accomplish either task through a single feed-forward pass, with real-time benefits and without any additional side information requirements including dark current, system response, temperature and detector-to-target range. Our experiments demonstrate that the proposed method outperforms the existing approaches used by the Mars Science Lab for pre-processing and calibration for remote sensing observations from the Mars rover, 'Curiosity'

    Oxidation of manganese in an ancient aquifer, Kimberley formation, Gale crater, Mars

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    The Curiosity rover observed high Mn abundances (>25 wt % MnO) in fracture‐filling materials that crosscut sandstones in the Kimberley region of Gale crater, Mars. The correlation between Mn and trace metal abundances plus the lack of correlation between Mn and elements such as S, Cl, and C, reveals that these deposits are Mn oxides rather than evaporites or other salts. On Earth, environments that concentrate Mn and deposit Mn minerals require water and highly oxidizing conditions; hence, these findings suggest that similar processes occurred on Mars. Based on the strong association between Mn‐oxide deposition and evolving atmospheric dioxygen levels on Earth, the presence of these Mn phases on Mars suggests that there was more abundant molecular oxygen within the atmosphere and some groundwaters of ancient Mars than in the present day

    In situ detection of boron by ChemCam on Mars

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    We report the first in situ detection of boron on Mars. Boron has been detected in Gale crater at levels Curiosity rover ChemCam instrument in calcium-sulfate-filled fractures, which formed in a late-stage groundwater circulating mainly in phyllosilicate-rich bedrock interpreted as lacustrine in origin. We consider two main groundwater-driven hypotheses to explain the presence of boron in the veins: leaching of borates out of bedrock or the redistribution of borate by dissolution of borate-bearing evaporite deposits. Our results suggest that an evaporation mechanism is most likely, implying that Gale groundwaters were mildly alkaline. On Earth, boron may be a necessary component for the origin of life; on Mars, its presence suggests that subsurface groundwater conditions could have supported prebiotic chemical reactions if organics were also present and provides additional support for the past habitability of Gale crater

    Plerixafor for autologous peripheral blood stem cell mobilization in patients previously treated with fludarabine or lenalidomide.

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    Fludarabine and lenalidomide are essential drugs in the front-line treatment of non-Hodgkin lymphoma (NHL) and multiple myeloma (MM), respectively. Data suggests that fludarabine and lenalidomide therapy may have a deleterious effect on stem cell mobilization. In the European compassionate use program, 48 patients (median age 57 years) previously treated with fludarabine (median 5 cycles; range: 1-7 cycles) were given plerixafor plus granulocyte colony-stimulating factor (G-CSF) for remobilization following a primary mobilization attempt. The overall median number of CD34+ cells collected was 2.3 × 10(6)/kg (range: 0.3-13.4). The minimum required number of CD34+ cells (≄2.0 × 10(6)/kg) was collected from 58% of patients in a median of 2 days. Thirty-five patients (median age = 57 years) previously treated with lenalidomide (median 5 cycles; range: 1-10 cycles) were given plerixafor plus G-CSF for remobilization. The overall median number of CD34+ cells collected was 3.4 × 10(6)/kg (range: 1.1-14.8). The minimum required number of CD34+ cells (≄2.0 × 10(6) per kg) was collected from 69% of patients in a median of 2 days. In conclusion, salvage mobilization with plerixafor plus G-CSF is successful in the majority of patients with MM previously treated with lenalidomide. In fludarabine-exposed patients, only 58% of patients will achieve successful salvage mobilization with plerixafor plus G-CSF, suggesting the need for novel mobilization regimens algorithms in this subgroup of patients

    Patient Disease Perceptions and Coping Strategies for Arthritis in a Developing Nation: A Qualitative Study

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    <p>Abstract</p> <p>Background</p> <p>There is little prior research on the burden of arthritis in the developing world. We sought to document how patients with advanced arthritis living in the Dominican Republic are affected by and cope with their disease.</p> <p>Methods</p> <p>We conducted semi-structured, one-to-one interviews with economically disadvantaged Dominican patients with advanced knee and/or hip arthritis in the Dominican Republic. The interviews, conducted in Spanish, followed a moderator's guide that included topics such as the patients' understanding of disease etiology, their support networks, and their coping mechanisms. The interviews were audiotaped, transcribed verbatim in Spanish, and systematically analyzed using content analysis. We assessed agreement in coding between two investigators.</p> <p>Results</p> <p>18 patients were interviewed (mean age 60 years, median age 62 years, 72% women, 100% response rate). Patients invoked religious and environmental theories of disease etiology, stating that their illness had been caused by God's will or through contact with water. While all patients experienced pain and functional limitation, the social effects of arthritis were gender-specific: women noted interference with homemaking and churchgoing activities, while men experienced disruption with occupational roles. The coping strategies used by patients appeared to reflect their beliefs about disease causation and included prayer and avoidance of water.</p> <p>Conclusions</p> <p>Patients' explanatory models of arthritis influenced the psychosocial effects of the disease and coping mechanisms used. Given the increasing reach of global health programs, understanding these culturally influenced perceptions of disease will be crucial in successfully treating chronic diseases in the developing world.</p

    Desert Research and Technology Studies (DRATS) 2010 Science Operations: Operational Approaches and Lessons Learned for Managing Science during Human Planetary Surface Missions

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    Desert Research and Technology Studies (Desert RATS) is a multi-year series of hardware and operations tests carried out annually in the high desert of Arizona on the San Francisco Volcanic Field. These activities are designed to exercise planetary surface hardware and operations in conditions where long-distance, multi-day roving is achievable, and they allow NASA to evaluate different mission concepts and approaches in an environment less costly and more forgiving than space.The results from the RATS tests allows election of potential operational approaches to planetary surface exploration prior to making commitments to specific flight and mission hardware development. In previous RATS operations, the Science Support Room has operated largely in an advisory role, an approach that was driven by the need to provide a loose science mission framework that would underpin the engineering tests. However, the extensive nature of the traverse operations for 2010 expanded the role of the science operations and tested specific operational approaches. Science mission operations approaches from the Apollo and Mars-Phoenix missions were merged to become the baseline for this test. Six days of traverse operations were conducted during each week of the 2-week test, with three traverse days each week conducted with voice and data communications continuously available, and three traverse days conducted with only two 1-hour communications periods per day. Within this framework, the team evaluated integrated science operations management using real-time, tactical science operations to oversee daily crew activities, and strategic level evaluations of science data and daily traverse results during a post-traverse planning shift. During continuous communications, both tactical and strategic teams were employed. On days when communications were reduced to only two communications periods per day, only a strategic team was employed. The Science Operations Team found that, if communications are good and down-linking of science data is ensured, high quality science returns is possible regardless of communications. What is absent from reduced communications is the scientific interaction between the crew on the planet and the scientists on the ground. These scientific interactions were a critical part of the science process and significantly improved mission science return over reduced communications conditions. The test also showed that the quality of science return is not measurable by simple numerical quantities but is, in fact, based on strongly non-quantifiable factors, such as the interactions between the crew and the Science Operations Teams. Although the metric evaluation data suggested some trends, there was not sufficient granularity in the data or specificity in the metrics to allow those trends to be understood on numerical data alone

    Comparative analysis of right ventricular strain in Fabry cardiomyopathy and sarcomeric hypertrophic cardiomyopathy

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    Aims To perform a comparative analysis of right ventricle (RV) myocardial mechanics, assessed by 2D speckle-tracking echocardiography (2D-STE), between patients with Fabry disease and patients with sarcomeric disease.Methods and results Patients with Fabry cardiomyopathy (FC) (n = 28) were compared with patients with sarcomeric hypertrophic cardiomyopathy (HCM), matched for degree of left ventricle hypertrophy (LVH) and demographic characteristics (n = 112). In addition, patients with Fabry disease and no LVH [phenotype-negative carriers of pathogenic alpha-galactosidase gene mutations (GLA LVH-)] (n = 28) were compared with age and sex-matched carriers of sarcomeric gene mutations without LVH [Phenotype-negative carriers of pathogenic sarcomeric gene mutations (Sarc LVH-)] (n = 56). Standard echocardiography and 2D-STE were performed in all participants. Despite a subtle impairment of RV global longitudinal strain (RV-GLS) was common in both groups, patients with FC showed a more prominent reduction of RV free wall longitudinal strain (RV-FWS) and lower values of difference between RV-FWS and RV-GLS (Delta RV strain), in comparison to individuals with HCM (P Conclusion Patients with FC show a specific pattern of RV myocardial mechanics, characterized by a larger impairment of RV-FWS and lower Delta RV strain in comparison to patients with HCM, which may be helpful in the differential diagnosis between these two diseases.[GRAPHICS].</p
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