977 research outputs found

    New radio observations of anomalous microwave emission in the HII region RCW175

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    We have observed the HII region RCW175 with the 64m Parkes telescope at 8.4GHz and 13.5GHz in total intensity, and at 21.5GHz in both total intensity and polarization. High angular resolution, high sensitivity, and polarization capability enable us to perform a detailed study of the different constituents of the HII region. For the first time, we resolve three distinct regions at microwave frequencies, two of which are part of the same annular diffuse structure. Our observations enable us to confirm the presence of anomalous microwave emission (AME) from RCW175. Fitting the integrated flux density across the entire region with the currently available spinning dust models, using physically motivated assumptions, indicates the presence of at least two spinning dust components: a warm component with a relatively large hydrogen number density n_H=26.3/cm^3 and a cold component with a hydrogen number density of n_H=150/cm^3. The present study is an example highlighting the potential of using high angular-resolution microwave data to break model parameter degeneracies. Thanks to our spectral coverage and angular resolution, we have been able to derive one of the first AME maps, at 13.5GHz, showing clear evidence that the bulk of the AME arises in particular from one of the source components, with some additional contribution from the diffuse structure. A cross-correlation analysis with thermal dust emission has shown a high degree of correlation with one of the regions within RCW175. In the center of RCW175, we find an average polarized emission at 21.5GHz of 2.2\pm0.2(rand.)\pm0.3(sys.)% of the total emission, where we have included both systematic and statistical uncertainties at 68% CL. This polarized emission could be due to sub-dominant synchrotron emission from the region and is thus consistent with very faint or non-polarized emission associated with AME.Comment: Accepted for publication in the Astrophysical Journa

    Commercial farming and agribusiness in South Africa and their changing roles in Africa’s agro-food system

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    Our paper is on commercial farming and agribusiness in South Africa and their changing roles in Africa’s agro-food system, as a response to debates and theoretical propositions about internal agrarian change in BRICS countries and their relations with other middle-income countries and the old hubs of capital. South Africa is of course an outlier among the BRICS group of countries, given its far smaller economy, and was included only in 2010, as the only candidate that could be seen as economically and politically dominant in Africa – though by last year, Nigeria had overtaken South Africa as the largest economy in Africa

    Intestinal tuberculosis in a child living in a country with a low incidence of tuberculosis: a case report

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    Background: Relatively common in adults, intestinal tuberculosis is considered rare in children and adolescents. The protean manifestations of intestinal tuberculosis mean that the diagnosis is often delayed (sometimes even for years), thus leading to increased mortality and unnecessary surgery. The main diagnostic dilemma is to differentiate intestinal tuberculosis and Crohn’s disease because a misdiagnosis can have dramatic consequences. Case presentation: A 13-year-old Caucasian, Italian female adolescent attended the Emergency Department complaining of abdominal pain, a fever of up to 38°C, night sweats, diarrhea with blood in stool, and a weight loss of about three kilograms over the previous two months. Physical examination revealed a marked skin pallor and considerable abdominal distension with relevant discomfort in all the abdominal quadrant. Laboratory tests revealed a decreased white blood cell count with anemia and increased C-reactive protein levels. The Mantoux tuberculin skin test was negative. A chest X-ray and an abdominal ultrasonography did not reveal any significant findings. The patient underwent colonoscopy that showed diffuse mucosal congestion and significant blood loss, and laparatomy showed small bowel and colon loops with a whitish appearance. A biopsy of the ileal mucosa revealed inflammation with noncaseating granulomas possibly due to bacterial infection. Given the suspicion of an opportunistic bacterial infection in a child with chronic inflammatory bowel disease (possibly Crohn’s disease), treatment with a third-generation cephalosporin was started. However, the abdominal pain, fever and poor general condition persisted and so, after 11 days, the patient underwent total body computed tomography and magnetic resonance imaging of the brain. On the basis of the radiological findings, miliary tuberculosis was suspected and bronchoscopy was performed and resulted positive for Mycobacterium tuberculosis. Miliary tuberculosis was confirmed and an effective treatment with four drugs was started. Conclusion: This case shows that the manifestations of intestinal tuberculosis can be very difficult to diagnose and mimic those of Chron’s disease. Total body computed tomography and laparotomy with an intestinal biopsy for the detection of Mycobacterium tuberculosis are the means of avoid the risks of a misdiagnosis in children with unexplained chronic abdominal problems

    Dual-readout Calorimetry

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    The RD52 Project at CERN is a pure instrumentation experiment whose goal is to understand the fundamental limitations to hadronic energy resolution, and other aspects of energy measurement, in high energy calorimeters. We have found that dual-readout calorimetry provides heretofore unprecedented information event-by-event for energy resolution, linearity of response, ease and robustness of calibration, fidelity of data, and particle identification, including energy lost to binding energy in nuclear break-up. We believe that hadronic energy resolutions of {\sigma}/E ≈\approx 1 - 2% are within reach for dual-readout calorimeters, enabling for the first time comparable measurement preci- sions on electrons, photons, muons, and quarks (jets). We briefly describe our current progress and near-term future plans. Complete information on all aspects of our work is available at the RD52 website http://highenergy.phys.ttu.edu/dream/.Comment: 10 pages, 10 figures, Snowmass White pape

    Minor Keywords of Political Theory: Migration as a Critical Standpoint. A collaborative project of collective writing

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    Coordinated and Edited by: N De Genova, M Tazzioli Co-Authored by: Claudia Aradau, Brenna Bhandar, Manuela Bojadzijev, Josue David Cisneros, N De Genova, Julia Eckert, Elena Fontanari, Tanya Golash-Boza, Jef Huysmans, Shahram Khosravi, Clara Lecadet, Patrisia MacĂ­as-Rojas, Federica Mazzara, Anne McNevin, Peter Nyers, Stephan Scheel, Nandita Sharma, Maurice Stierl, Vicki Squire, M Tazzioli, Huub van Baar and William Walter

    Evidence For The Production Of Slow Antiprotonic Hydrogen In Vacuum

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    We present evidence showing how antiprotonic hydrogen, the quasistable antiproton-proton (pbar-p) bound system, has been synthesized following the interaction of antiprotons with the hydrogen molecular ion (H2+) in a nested Penning trap environment. From a careful analysis of the spatial distributions of antiproton annihilation events, evidence is presented for antiprotonic hydrogen production with sub-eV kinetic energies in states around n=70, and with low angular momenta. The slow antiprotonic hydrogen may be studied using laser spectroscopic techniques.Comment: 5 pages with 4 figures. Published as Phys. Rev. Letters 97, 153401 (2006), in slightly different for
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