749 research outputs found

    Exploring the Ethics of Human Space Travel: Navigating the Challenges and Implications of Missions Past, Present, and Future

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    This comprehensive exploration delves into the multifaceted landscape of human space travel, spanning physiological challenges, astronaut training, spacecraft manufacturing, ethical considerations, societal influences, and technological frontiers. The study elucidates the physiological impacts of microgravity on astronauts, emphasizing the necessity of personalized interventions and rigorous exercise protocols. Psychological dimensions, including isolation, interpersonal dynamics, and support systems, emerge as critical considerations. Astronaut training is dissected, encompassing physical conditioning, systems proficiency, and cultural competence. The paper delves into spacecraft manufacturing, emphasizing adherence to stringent standards, quality control measures, and the integration of additive manufacturing. Space governance challenges, the role of the private sector, and environmental impacts are scrutinized. Cultural and societal dimensions, including the influence of science fiction and ethical considerations, are explored. The study advocates for adaptive ethical frameworks, public engagement, and responsible governance. Technological frontiers such as ion propulsion, AI integration, solar power harvesting, and quantum communication are assessed for their transformative potential and ethical implications. This interdisciplinary examination provides a holistic perspective on the challenges and opportunities shaping the future of human space travel. It advocates for a balanced integration of physiological, psychological, ethical, technological, and societal considerations, emphasizing the imperative of responsible and sustainable practices as humanity ventures further into the cosmos

    Major Colonic Problems in Human Homotransplant Recipients

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    The chemokine CXCL13 in acute neuroborreliosis

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    Objective Recent studies have suggested an important role of the B cell chemoattractant CXCL13 in acute neuroborreliosis (NB). Our aim was to confirm the diagnostic role of CXCL13 and to evaluate its relevance as a therapy response and disease activity marker in NB. Methods CXCL13 was measured in cerebrospinal fluid (CSF) and serum of patients with NB (n = 28), systemic borreliosis (SB, n = 9), Guillaine-Barre syndrome (GBS, n = 11), Bell's palsy (BP, n = 19), other cranial nerve palsies (CNP, n = 5), cephalgia (C, n = 20), bacterial CNS infections (B-CNS-I, n = 16) and viral CNS infections (V-CNS-I, n = 18). For follow-up studies, serial sample pairs were evaluated from 25 patients with NB (n = 56), 11 with B-CNS-I (n = 25) and 14 with V-CNS-I (n = 36). Results CSF-CXCL13 was significantly elevated in NB compared with other neurological diseases (p<0.001). Using receiver operating characteristic analysis, 337 ng/g was determined as a cut-off with a sensitivity of 96.4% and a specificity of 96.9%. Of all the parameters investigated, CSF CXCL13 showed the fastest response to antibiotic therapy, decreasing significantly (p = 0.008) within 1 week. In untreated patients, CSF CXCL13 was elevated in patients with a short duration of disease. Borrelia burgdorferi antibody index showed no significant (p = 0.356) change over follow-up. Conclusions The study confirms the relevance of CXCL13 as a diagnostic biomarker of NB and suggests that CSF CXCL13 in NB is linked to duration of disease and could be a marker of disease activity and response to antibiotic therapy

    Shwartzman reaction after human renal homotransplantation.

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    In three human recipients, five renal homografts were destroyed within a few minutes to hours after their revascularization in the new host. The kidneys, removed one to 54 days later, had cortical necrosis. The major vessels were patent, but the arterioles and glomeruli were the site of fibrin deposition. There was little or no fixation of host immunoglobulins in the homografts. The findings were characteristic of a generalized Shwartzman reaction. Although the cause (or causes) of the Shwartzman reaction in our patients is not known, they may have been conditioned by the bacterial contamination and hemolysis that often attend hemodialysis, by immunosuppression and by the transplantation itself. Some of the patients have preformed lymphocytotoxic antibodies. Thus, certain patients may be predisposed. High-risk patients should be recognized and treated prophylactically with anticoagulants

    Modelling the penumbra in computed tomography

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    Background: In computed tomography (CT), the spot geometry is one of the main sources of error in CT images. Since X-rays do not arise from a point source, artefacts are produced. In particular there is a penumbra effect, leading to poorly defined edges within a reconstructed volume. Penumbra models can be simulated given a fixed spot geometry and the known experimental setup. Objective: This paper proposes to use a penumbra model, derived from Beer’s law, both to confirm spot geometry from penumbra data, and to quantify blurring in the image. Methods: Two models for the spot geometry are considered; one consists of a single Gaussian spot, the other is a mixture model consisting of a Gaussian spot together with a larger uniform spot. Results: The model consisting of a single Gaussian spot has a poor fit at the boundary. The mixture model (which adds a larger uniform spot) exhibits a much improved fit. The parameters corresponding to the uniform spot are similar across all powers, and further experiments suggest that the uniform spot produces only soft X-rays of relatively low-energy. Conclusions: Thus, the precision of radiographs can be estimated from the penumbra effect in the image. The use of a thin copper filter reduces the size of the effective penumbra

    A low-power data acquisition system for geomagnetic observatories and variometer stations

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    A modern geomagnetic observatory must provide data of high stability, continuity, and resolution. The INTERMAGNET network has therefore specified quantitative criteria to ensure a high quality standard of geomagnetic observatories. Here, we present a new data acquisition system which was designed to meet these criteria, in particular with respect to 1 Hz data. This system is based on a Raspberry Pi embedded PC and runs a C+ +  data acquisition software. As a result, the data acquisition system is modular, cheap, and flexible, and it can be operated in remote areas with limited power supply. In addition, the system is capable of near-real-time data transmission, using a reverse SSH tunnel to work with any network available. The system hardware was successfully tested at the Niemegk observatory for a period of 1 year and subsequently installed at the Tatuoca observatory in Brazil
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