57 research outputs found

    S17(0) Determined from the Coulomb Breakup of 83 MeV/nucleon 8B

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    A kinematically complete measurement was made of the Coulomb dissociation of 8B nuclei on a Pb target at 83 MeV/nucleon. The cross section was measured at low relative energies in order to infer the astrophysical S factor for the 7Be(p,gamma)8B reaction. A first-order perturbation theory analysis of the reaction dynamics including E1, E2, and M1 transitions was employed to extract the E1 strength relevant to neutrino-producing reactions in the solar interior. By fitting the measured cross section from Erel = 130 keV to 400 keV, we find S17(0) = 17.8 (+1.4, -1.2) eV b

    Tuberculosis Outbreak Investigations in the United States, 2002–2008

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    To understand circumstances of tuberculosis transmission that strain public health resources, we systematically reviewed Centers for Disease Control and Prevention (CDC) staff reports of US outbreaks in which CDC participated during 2002–2008 that involved >3 culture-confirmed tuberculosis cases linked by genotype and epidemiology. Twenty-seven outbreaks, representing 398 patients, were reviewed. Twenty-four of the 27 outbreaks involved primarily US-born patients; substance abuse was another predominant feature of outbreaks. Prolonged infectiousness because of provider- and patient-related factors was common. In 17 outbreaks, a drug house was a notable contributing factor. The most frequently documented intervention to control the outbreak was prioritizing contacts according to risk for infection and disease progression to ensure that the highest risk contacts were completely evaluated. US-born persons with reported substance abuse most strongly characterized the tuberculosis outbreaks in this review. Substance abuse remains one of the greatest challenges to controlling tuberculosis transmission in the United States

    Babesia divergens–like Infection, Washington State

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    Most reported U.S. zoonotic cases of babesiosis have occurred in the Northeast and been caused by Babesia microti. In Washington State, three cases of babesiosis have been reported previously, which were caused by WA1 (for “Washington 1”)-type parasites. We investigated a case of babesiosis in Washington in an 82–year-old man whose spleen had been removed and whose parasitemia level was 41.4%. The complete 18S ribosomal RNA gene of the parasite was amplified from specimens of his whole blood by polymerase chain reaction. Phylogenetic analysis showed the parasite is most closely related, but not identical, to B. divergens (similarity score, 99.5%), a bovine parasite in Europe. By indirect fluorescent-antibody testing, his serum reacted to B. divergens but not to B. microti or WA1 antigens. This case demonstrates that babesiosis can be caused by novel parasites detectable by manual examination of blood smears but not by serologic or molecular testing for B. microti or WA1-type parasites

    New evidence for a subshell gap at N = 32

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    Abstract An 879.9(2) keV γ -ray transition has been identified following the β decay of 58 V and assigned as the 2 58 Cr 34 . A peak in the energies of the first excited 2 + states for the even-even chromium isotopes is now evident at 56 Cr 32 , providing empirical evidence for a significant subshell gap at N = 32. The appearance of this neutron subshell closure for neutron-rich nuclides may be attributed to the diminished π1f 7/2 -ν1f 5/2 monopole proton-neutron interaction as protons are removed from the 1f 7/2 single-particle orbital. 2001 Elsevier Science B.V. All rights reserved. PACS: 21.60.Cs; 23.20.Lv; 27.40.+z Trends in nuclear masses and binding energies have suggested nuclei associated with nucleon numbers expected to be maximum at midshell. However, the development of collectivity away from major closed shells may be inhibited by the presence of subshell closures, or minor shell gaps. In order to study such phenomena, experimental probes of quadrupole collectivity may be utilized. One measure of the extent of quadrupole collectivity in even-even nuclear systems is the energy of the first excited 2 + state, E(2 + 1 ). According to Grodzins [2

    Interventions to improve contact tracing for tuberculosis in specific groups and in wider populations: an evidence synthesis

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    Background The tracing and screening of people who have had contact with an active case of tuberculosis (TB) is an important element of TB control strategies. Objectives This study aimed to carry out a review of evidence regarding TB contact tracing, with a particular emphasis on research that was applicable to TB contact tracing in specific population groups in the UK. Design An evidence synthesis of literature of any study design on TB contact tracing in developed countries was carried out. Setting Any setting. Population Individuals found to have active TB disease, and people who have come into contact with them. Interventions Contact-tracing investigations. Main outcome measures Any outcome related to TB infection, contact investigations and/or the views of staff, people with TB disease, or their contacts. Data sources Searches for research published 1995 onwards were undertaken in the following databases: MEDLINE via Ovid SP, EMBASE via Ovid SP, EconLit via Ovid SP, PsycINFO via Ovid SP, Social Policy and Practice via Ovid SP, Cumulative Index to Nursing and Allied Health Literature via EBSCOhost, Science and Social Science Citation Indices via Web of Science and The Cochrane Library via Wiley Online Library. Review methods The study comprised a review of TB contact tracing in specific population groups and a review in wider populations. A narrative synthesis was completed and a logic model was developed from the literature. Results There were 112 articles in the review: 23 related to specific populations and 89 related to wider populations. The literature was of limited quality, with much general description of investigations. We identified only two (uncontrolled) studies that could be considered evaluative. Although the limitations of the evidence should be recognised, the review suggested the following: the value of a location-based approach, working with local communities and the media, partnership working, using molecular epidemiological testing, ensuring adequate systems and addressing fear of stigma. The literature on investigations for specific populations has much concordance with that reporting findings from wider population groups. The recognised limitations of conventional investigation methods may, however, be exacerbated in specific populations. Limitations The English-language inclusion criterion may have limited the breadth of countries represented. A meta-analysis was not possible owing to the nature of the literature. Relevant studies may have been missed by our searches, which used terminology relating to contact tracing rather than to active case finding or screening. Conclusions The review identified a sizeable volume of literature relating to contact investigations. However, it is currently predominantly descriptive, with little evaluative work underpinning investigations in either specific or wider populations. Our findings are, therefore, based on limited evidence. Further research is required if robust conclusions are to be made. Future work Research should further explore the development of measures that can be used to compare the effectiveness of different contact investigations, in studies using evaluative designs

    Investigation of Surface Wave Transmission Systems At Millimeter Wave Frequencies

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    Waveguide used in the millimeter wave frequency range is very expensive. Despite the high losses, propagation of waves at these frequencies along a single or multiple copper wire surface wave system could mean a large economic savings. This assumes these higher losses are tolerable. This investigation is concerned with surface wave transmission at millimeter frequencies, including economical, low loss launching and receiving devices. Properties of these devices will be studied both theoretically and experimentally

    Men, Munitions, and Material in the War for American Independence

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    An old axiom insists that the best histories are records of the negotiations themselves. This may be quite true, but since this is not to be a history, and since the records - thatis the communications of the foreign ministers with Congress - take up twelve large octavo volumes; I feel justified in presenting only the portions of those documents which seem to be particularly apropos. The labor in the essay, then, is not so much in its content; but rather in the lack of it. The task of evaluating and discarding facts proved to be no easy chore, and since there was so much material, it might seem at first blush that the matter lacks the correct proportions. However, I feel certain that every line contributes its own bit to the general context, and since I have stated factswith care and drawn conclusions with caution; I feel that any omission would distort those facts, and negate the conclusions
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