451 research outputs found

    Cryogenic Vacuum Insulation for Vessels and Piping

    Get PDF
    Cryogenic vacuum insulation systems, with proper materials selection and execution, can offer the highest levels of thermal performance. Three areas of consideration are vital to achieve the optimum result: materials, representative test conditions, and engineering approach for the particular application. Deficiency in one of these three areas can prevent optimum performance and lead to severe inefficiency. Materials of interest include micro-fiberglass, multilayer insulation, and composite arrangements. Cylindrical liquid nitrogen boil-off calorimetry methods were used. The need for standard thermal conductivity data is addressed through baseline testing. Engineering analysis and design factors such as layer thickness, density, and practicality are also considered

    New Measurement of the Cosmic-Ray Positron Fraction from 5 to 15 GeV

    Get PDF
    We present a new measurement of the cosmic-ray positron fraction at energies between 5 and 15 GeV with the balloon-borne HEAT-pbar instrument in the spring of 2000. The data presented here are compatible with our previous measurements, obtained with a different instrument. The combined data from the three HEAT flights indicate a small positron flux of non-standard origin above 5 GeV. We compare the new measurement with earlier data obtained with the HEAT-e+- instrument, during the opposite epoch of the solar cycle, and conclude that our measurements do not support predictions of charge sign dependent solar modulation of the positron abundance at 5 GeV.Comment: accepted for publication in PR

    Older adults experiences of rehabilitation in acute health care

    Get PDF
    Rehabilitation is a key component of nursing and allied healthcare professionals’ roles in most health and social care settings. This paper reports on stage 2 of an action research project to ascertain older adult's experience of rehabilitation. Twenty postdischarge interviews were conducted and the interview transcripts were analysed using thematic content analysis. All older adults discharged from an acute older acute rehabilitation ward to their own homes in the community were eligible to participate. The only exclusion criterion was older adults who were thought to be unable to give consent to participate by the nurse in charge and the researcher. Whilst 92 older adults were eligible to participate in this research study, only 20 were interviewed. The findings from this study suggest that older adults valued communication with health professionals but were aware of their time constraints that hindered communication. This study suggests that both nurses and allied health professionals are not actively providing rehabilitative services to promote health and well-being, which contradicts the focus of active ageing. Furthermore, there was evidence of unmet needs on discharge, and older adults unable to recall the professions that were involved in their interventions and the rationale for therapy input. It is suggested that further research is needed to explore the effectiveness of allied health rehabilitation in the acute setting. This study highlights the need for further research into older adults’ perceptions of the rehabilitation process in the acute setting

    Measurements of cosmic-ray energy spectra with the 2nd CREAM flight

    Full text link
    During its second Antarctic flight, the CREAM (Cosmic Ray Energetics And Mass) balloon experiment collected data for 28 days, measuring the charge and the energy of cosmic rays (CR) with a redundant system of particle identification and an imaging thin ionization calorimeter. Preliminary direct measurements of the absolute intensities of individual CR nuclei are reported in the elemental range from carbon to iron at very high energy.Comment: 4 pages, 3 figures, presented at XV International Symposium on Very High Energy Cosmic Ray Interactions (ISVHECRI 2008

    Limiting Student Speech: A Narrow Path Toward Success. A Response to Challenging the Common Guidelines in Social Justice Education

    Get PDF
    In this response, Minnick asserts that unequal representation of students\u27 voices, an idea presented in Sensoy and DiAngelo’s “Challenging the Common Guidelines in Social Justice Education,” presents multiple negative classroom implications. Foremost, Minnick argues that Sensoy and DiAngelo’s lack of clarity regarding when a teacher should limit student speech (either before the student begins to talk or midcomment) has a large effect on the success of their strategy. Second, Sensoy and DiAngelo’s discussion strategy may result in the targeting of minority students and the judging of students. These concerns are driven by considerations of how teachers’ relationships with students influence their ability to effectively limit and enable student speech

    Energy spectra of cosmic-ray nuclei at high energies

    Full text link
    We present new measurements of the energy spectra of cosmic-ray (CR) nuclei from the second flight of the balloon-borne experiment Cosmic Ray Energetics And Mass (CREAM). The instrument included different particle detectors to provide redundant charge identification and measure the energy of CRs up to several hundred TeV. The measured individual energy spectra of C, O, Ne, Mg, Si, and Fe are presented up to 1014\sim 10^{14} eV. The spectral shape looks nearly the same for these primary elements and it can be fitted to an E2.66±0.04E^{-2.66 \pm 0.04} power law in energy. Moreover, a new measurement of the absolute intensity of nitrogen in the 100-800 GeV/nn energy range with smaller errors than previous observations, clearly indicates a hardening of the spectrum at high energy. The relative abundance of N/O at the top of the atmosphere is measured to be 0.080±0.0250.080 \pm 0.025 (stat.)±0.025 \pm 0.025 (sys.) at \sim 800 GeV/nn, in good agreement with a recent result from the first CREAM flight.Comment: 32 pages, 10 figures. Accepted for publication in Astrophysical Journa

    Cosmic-Ray Proton and Helium Spectra from the First CREAM Flight

    Full text link
    Cosmic-ray proton and helium spectra have been measured with the balloon-borne Cosmic Ray Energetics And Mass experiment flown for 42 days in Antarctica in the 2004-2005 austral summer season. High-energy cosmic-ray data were collected at an average altitude of ~38.5 km with an average atmospheric overburden of ~3.9 g cm2^{-2}. Individual elements are clearly separated with a charge resolution of ~0.15 e (in charge units) and ~0.2 e for protons and helium nuclei, respectively. The measured spectra at the top of the atmosphere are represented by power laws with a spectral index of -2.66 ±\pm 0.02 for protons from 2.5 TeV to 250 TeV and -2.58 ±\pm 0.02 for helium nuclei from 630 GeV/nucleon to 63 TeV/nucleon. They are harder than previous measurements at a few tens of GeV/nucleon. The helium flux is higher than that expected from the extrapolation of the power law fitted to the lower-energy data. The relative abundance of protons to helium nuclei is 9.1 ±\pm 0.5 for the range from 2.5 TeV/nucleon to 63 TeV/nucleon. This ratio is considerably smaller than the previous measurements at a few tens of GeV/nucleon.Comment: 20 pages, 4 figure

    Elemental energy spectra of cosmic rays measured by CREAM-II

    Full text link
    We present new measurements of the energy spectra of cosmic-ray (CR) nuclei from the second flight of the balloon-borne experiment CREAM (Cosmic Ray Energetics And Mass). The instrument (CREAM-II) was comprised of detectors based on different techniques (Cherenkov light, specific ionization in scintillators and silicon sensors) to provide a redundant charge identification and a thin ionization calorimeter capable of measuring the energy of cosmic rays up to several hundreds of TeV. The data analysis is described and the individual energy spectra of C, O, Ne, Mg, Si and Fe are reported up to ~ 10^14 eV. The spectral shape looks nearly the same for all the primary elements and can be expressed as a power law in energy E^{-2.66+/-0.04}. The nitrogen absolute intensity in the energy range 100-800 GeV/n is also measured.Comment: 4 pages, 3 figures, presented at ICRC 2009, Lodz, Polan

    Differential expression of the invasion-associated locus B (ialB) gene of Bartonella bacilliformis in response to environmental cues

    Get PDF
    Bartonella bacilliformis is the causative agent of the biphasic human disease, Oroya fever. During the primary disease phase, up to 100% of the circulating erythrocytes can be parasitized and 80% lysed. During the secondary phase of this disease, bacterial invasion shifts to endothelial cells lining the vasculature. B. bacilliformis is transferred between human hosts by the sandfly, Lutzomyia verrucarum. To investigate the regulation of ialB by environmental cues signaling vector-to-host transmission; nuclease protection assays were performed to compare the amount of ialB mRNA in bacteria subjected to temperature shift, pH change, oxidative stress, or hemin limitation. The amount of ialB mRNA increased by 223-310% in acid-treated samples and decreased by 28-39% in base-treated samples as compared to bacteria kept at pH 7.2. B. bacilliformis samples showed a 56-63% and 74-80% decrease in ialB mRNA when shifted to 37 degrees C from growth temperatures of 20 and 30 degrees C, respectively. Oxidative stress (1 mM H(2)O(2)) and hemin limitation had no significant effect on mRNA levels. Determination of IalB protein amounts using SDS-PAGE and immunoblotting showed the greatest amounts of IalB under acidic conditions or at 20 degrees C. The least amount of IalB was synthesized under basic conditions or at 37 degrees C. The viability of wild-type B. bacilliformis under the various experimental culture conditions was determined and found not to affect ialB mRNA amounts in these experiments. Finally, we compared the survival of wild-type and ialB mutant B. bacilliformis and found no difference in the viability of these two strains, demonstrating that IalB does not aid bacterial survival under these conditions
    corecore