11 research outputs found

    Self-Similar Shocks in Polytropic Gas Flows around Star-Forming Regions

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    Self-similar shock solutions in spherically symmetric polytropic gas flows are constructed and analyzed in contexts of proto-star formation processes. Among other possible solutions, we model a similarity shock across the sonic critical curve with an inner free-fall core collapse and a simultaneous outer expansion of the extended envelope; the separation or stagnation surface between these two flow zones travels outwards in a self-similar manner at a variable speed. One readily obtains accretion shock solutions. Semi-complete self-similar solutions across the sonic critical curve either once or twice without shocks can also be constructed. Features of star formation clouds of our polytropic model include the mass density scaling in the outer flow zone ρr2/(2γ)\rho\propto r^{-2/(2-\gamma)}, the temperature scalings of the inner flow zone Tr3(γ1)/2T\propto r^{-3(\gamma-1)/2} and of the outer flow zone Tr2(γ1)/(2γ)T\propto r^{-2(\gamma-1)/(2-\gamma)}, and the variable central mass accretion rate M˙=k3/2t(33γ)m0/G\dot{M}=k^{3/2}t^{(3-3\gamma)}m_0/G where γ\gamma is the polytropic index, kk is a constant, m0m_0 is the core mass, and GG is the gravitational constant. Spectral line profiles characteristic of the `envelope expansion with core collapse' (EECC) shock solutions are expected. Random magnetic field permeated in a partially ionized cloud can be incorporated into this theoretical polytropic model framework. We discuss briefly our results in context of the oft-observed starless B335 cloud system as an example.Comment: 10 pages, 3 figures, accepted by MNRA

    The nature of the compact HII region Sh 2-89 and its stellar content

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    We present an analysis of the structure and properties of the compact HII region Sh 2-89, and certain of the young stellar objects (YSOs) within this regime, using mid-infrared (MIR) mapping derived from the Spitzer Space Telescope (SST) and visual slit spectroscopy of the inner regions of the source. We show that the region has a bipolar structure, and contains a variety of Class I and II YSOs. Much of the MIR emission appears to be dominated by PAH emission bands, which cause strong increases in flux in the 5.8 and 8.0 microns photometric channels, whilst the variation of H_alpha, [NII] at 6583 A, [SII] at 6716+6731 A, and MIR emission profiles confirms the presence of complex ionisation fronts, and ionisation stratification.Comment: 12 pages, 6 figures, Accepted for publication in MNRAS. 33 pages in arXi

    Drug sensitivity of Plasmodium falciparum in vivo and in vitro in Brazzaville (Congo)

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    Various projects were launched in 1993 to monitor the chemosensitivity of Plasmodium falciparum in Congo. Resistance of 34 strains in Brazzaville to chloroquine, quinine and mefloquine and of 35 to halofantrine was investigated in an in vitro survey using an isotopic micro test. The resistance rates were 61.8, 14.7, 3.0 and 0.0% respectively. Thus, the chemoresistance which first appeared in 1990 is confirmed and is stable in the population. This finding was further confirmed by a parallel in vitro analysis of sensitivity to chloroquine in Brazzaville. A chloroquine monitoring network is now being established throughout the country based on simplified WHO tests of 100 asymptomatic schoolchildren conducted every six months. The first results in 1993, from three Southern regions indicate that parasites are found in 20 to 60% of cases seven days after a standard 3 day treatment with 25 mg/kg, according to the region. The results of in vitro and in vivo tests are very variable. Indeed, the value of such results for these tests for national monitoring is questionable: a more reliable system of identifying true therapeutic failures would be better suited.Afin de poursuivre la surveillance de la chimiosensibilité de Plasmodium falciparum au Congo, différentes actions ont été ccconduites en 1993. A Brazzaville une enquête in vitro utilisant un microtest isotopique a permis de tester 34 souches face à la choloroquine, la quinine et la méfloquine, et 35 face à l'halofantrine. Avec des taux de résistance à ces drogues de respectivement 61,8%, 14.7%, 3 et 0%, la stabilité de la chimiorésistance in vitro, entrevue en 1990, se confirme actuellement. Cette stabilité dans la capitale est également confirmée par l'étude de la chloroquinosensibilité in vivo menée parallèlement lors de cette enquête. Dans le reste du pays, un réseau de chloroquinosurveillance se met en place sous forme de tests OMS simplifiés réalisés chez 100 écoliers asymptomatiques tous les six mois. Les premiers résultats obtenus en 1993 dans trois régions du sud du pays montrent que, après un traitemetn standard de 25 mg/kg, pendant 3 jours, des parasites sont retrouvés à J7 dans 20 à 60% des cas selon les endroits. Par ailleurs les résultats des tests in vitro et in vivo réalisés sur les mêmes souches sont très différent entre eux. Cet élément conduit les auteurs à s'interroger sur la signification des résultats de tels tests dans le cadre d'une surveillance nationale. Le recours à un système fiable de détection des vrais échecs thérapeutiques semble plus adapté à cet objectif

    Male-specific late effects in adult hematopoietic cell transplantation recipients: a systematic review from the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research and Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation.

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    Male-specific late effects after hematopoietic cell transplantation (HCT) include genital chronic graft-versus-host disease (GvHD), hypogonadism, sexual dysfunction, infertility, and subsequent malignancies. They may be closely intertwined and cause prolonged morbidity and decreased quality of life after HCT. We provide a systematic review of male-specific late effects in a collaboration between transplant physicians, endocrinologists, urologists, dermatologists, and sexual health professionals through the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research, and the Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation. The systematic review summarizes incidence, risk factors, screening, prevention and treatment of these complications and provides consensus evidence-based recommendations for clinical practice and future research

    Male-specific late effects in adult hematopoietic cell transplantation recipients: a systematic review from the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research and Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation.

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    BACKGROUND Male-specific late effects after hematopoietic cell transplantation (HCT) include genital chronic graft-versus-host disease (GvHD), hypogonadism, sexual dysfunction, infertility, and subsequent malignancies, such as prostate, penile, and testicular cancer. They may be closely intertwined and cause prolonged morbidity and decreased quality of life after HCT. OBJECTIVE Here, we provide a systematic review of male-specific late effects in a collaboration between transplant physicians, endocrinologists, urologists, dermatologists, and sexual health professionals through the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research, and the Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation. STUDY DESIGN We utilized systematic review methodology to summarize incidence, risk factors, screening, prevention and treatment of these complications and provide consensus evidence-based recommendations for clinical practice and future research. RESULTS Most of the evidence regarding male GvHD is still based on limited data, precluding strong therapeutic recommendations. We therefore recommend to systematically screen for male genital GvHD regularly and report it to large registries to allow for a better understanding. Future research should also address treatment since little published evidence is available to date. Male-specific endocrine consequences of HCT include hypogonadism which may also affect bone health. Since the evidence is scarce, current recommendations for hormone substitution and/or bone health treatment are based on similar principles as for the general population. Following HCT, sexual health decreases and this topic should be addressed at regular intervals. Future studies should focus on interventional strategies to address sexual dysfunction. Infertility remains prevalent in patients having undergone myeloablative conditioning, which warrants offering sperm preservation in all HCT candidates. Most studies on fertility rely on descriptive registry analysis and surveys, hence the importance of reporting post-HCT conception data to large registries. Although the quality of evidence is low, the development of cancer in male genital organs does not seem more prevalent than in the general population; however, subsequent malignancies in general seem to be more prevalent in males than females, and special attention should be given to skin and oral mucosa. CONCLUSION Male-specific late effects, probably more under-reported than female-specific complications, should be systematically considered during the regular follow-up visits of male survivors who have undergone HCT. Care of patients with male-specific late effects warrants close collaboration between transplant physicians and specialists from other involved disciplines. Future research should be directed towards better data collection on male-specific late effects and on studies about the interrelationship between these late effects, to allow the development of evidence based effective management practices
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