784 research outputs found
Recent Studies of the Cosmic-Ray Latitude Effect at High Altitudes
With an improved Geiger counter telescope, having an angular aperture of about ±15° from its axis, a series of balloon flights was made in August and September, 1947, at seven stations extending from San Antonio, Texas, to Saskatoon, Canada. The axis of the telescope in all cases was oriented in a vertical direction. All sets of equipment were compared with a standard to reduce all results to a common basis. The standard sets, in turn, were compared with an accurately constructed telescope which had been used to make an absolute determination of cosmic-ray intensity at the vertical in Pasadena.
Two flights were made from each of the seven stations. The agreement between flights made within a few hours of each other at a given station is very good. Results from two flights made at a given station several days apart are not in general as consistent. Likewise, no monotonic increase of the radiation with increase of latitude was observed. Evidence is presented for rather large fluctuations at high altitudes of the lower energy components of cosmic rays. Some of the reasons for these fluctuations are discussed
Cosmic-ray effects from solar flares and magnetic storms
Cosmic-ray data taken during the period of a solar flare and the magnetic storm that followed 26.5 hours later during July, 1946, are reported. The results following the flare agree with those of other investigators and, in addition, serve to establish the fact that the start of the cosmic-ray effect and the visual part of the solar flare were simultaneous. It is pointed out that increases of cosmic rays during solar flares suggest a mode of origin of the rays. The lack of effect of most solar flares on cosmic-ray intensity is noted and differences in intensity of the flares given as a possible reason. A high altitude balloon flight with an electroscope during the magnetic storm gave results in agreement with the current-sheet hypothesis of such storms but a serious objection to this hypothesis is given
A New Cosmic-Ray Telescope for High Altitudes
A cosmic-ray telescope is described having an angular resolution of approximately ±15°. The distance between the two outermost trays, each containing 8 Geiger counters, is 1 meter. The area of each tray is approximately 24×24 cm^2. Triple coincidences modulate a transmitter and the signals, including those giving the air pressure and temperature of the instrument, are recorded on the ground. The counting rate is such that at the peak of the curve the relative probable error during a 4 minute interval is about 1.5 percent.
Accidental counts are found to be nearly negligible at all altitudes and latitudes, but some correction needs to be made for loss in efficiency because of the inherent dead time of the counters. An absolute determination of cosmic-ray intensity at the vertical at Pasadena was made in order to express the results as nearly as possible independently of the apparatus used
Neutrino induced transitions between the ground states of the A=12 triad
Neutrino induced reactions on C, an ingredient of liquid
scintillators, have been studied in several experiments. We show that for
currently available neutrino energies, 300 MeV, calculated
exclusive cross sections CN for both muon
and electron neutrinos are essentially model independent, provided the
calculations simultaneously describe the rates of several other reactions
involving the same states or their isobar analogs. The calculations agree well
with the measured cross sections, which can be therefore used to check the
normalization of the incident neutrino spectrum and the efficiency of the
detector.Comment: 9 pages REVTEX, 2 postscript figures, text and figures available at
http://www.krl.caltech.edu/preprints/MAP.htm
Machismo, marianismo, and negative cognitive-emotional factors: Findings from the Hispanic Community Health Study/Study of Latinos Sociocultural Ancillary Study.
There is limited research on the traditional Hispanic male and female gender roles of machismo and marianismo, respectively, in relation to negative cognitions and emotions. Given the vulnerability of Hispanics to negative cognitions and emotions, it is important to examine sociocultural correlates of emotional distress. Therefore, we examined associations of machismo and marianismo with negative cognitive-emotional factors (i.e., depression symptoms; cynical hostility; and trait anxiety and anger) in the Hispanic Community Health Study/Study of Latinos Sociocultural Ancillary Study, a cross-sectional cohort study of sociocultural and psychosocial correlates of cardiometabolic health. Participants were aged 18–74 years and self-identified as Hispanic of Central American, Cuban, Dominican, Mexican, Puerto Rican, South American, and other Hispanic background (N = 4,426). Results revealed that specific components of machismo (traditional machismo) and marianismo (family and spiritual pillar dimensions) were associated with higher levels of negative cognitions and emotions after adjusting for socio-demographic factors (p < .05); these associations remained consistent across sex, Hispanic background group, and acculturation. Findings can inform mental health interventions and contribute to our understanding of the importance of gender role socialization in the context of self-reported negative cognitive-emotional factors in Hispanics
Perceptions of Cancer Risk/Efficacy and Cancer-Related Risk Behaviors : Results From the HCHS/SOL Sociocultural Ancillary Study
This study evaluated the associations among perceived risk, perceived efficacy, and engagement in six cancer-related risk behaviors in a population-based Hispanic/Latino sample. Interviews were conducted with 5,313 Hispanic/Latino adults as part of the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) Sociocultural Ancillary Study. Participants were recruited from the study's four field centers (Bronx, NY; Chicago, IL; Miami, FL; San Diego, CA) between February 2010 and June 2011. Perceived risk and perceived efficacy were assessed with questions drawn from the Health Interview National Trends Survey. More than half of the sample endorsed perceived risk of cancer associated with the six evaluated behaviors, as well as general perceived efficacy for preventing cancer. Adjusted logistic regression analyses demonstrated significant differences across Hispanic/Latino background groups for perceived risk associated with high consumption of alcohol and saturated fat, low consumption of fruits and vegetables, and insufficient exercise but not with smoking or low consumption of fiber. Differences were also found for the belief, "It seems like everything causes cancer" but not for other perceived efficacy items. Perceived cancer risk and perceived efficacy for preventing cancer were neither independently nor interactively associated with engagement in cancer-related risk behaviors after controlling for sociodemographic covariates. Results suggest that perceptions of risk and efficacy with regard to cancer vary across Hispanic/Latino background groups, and therefore background group differences should be considered in prevention efforts. Perceived risk and perceived efficacy were not related to cancer-related risk behaviors among Hispanics/Latinos. Further work is needed to evaluate determinants of cancer-related risk in this population
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An automated, 0.5Hz nano-foil target positioning system for intense laser plasma experiments
We report on a target system supporting automated positioning of nano-targets with a precision resolution of in three dimensions. It relies on a confocal distance sensor and a microscope. The system has been commissioned to position nanometer targets with 1Hz repetition rate. Integrating our prototype into the table-top ATLAS 300 TW-laser system at the Laboratory for Extreme Photonics in Garching, we demonstrate the operation of a 0.5Hz laser-driven proton source with a shot-to-shot variation of the maximum energy about 27% for a level of confidence of 0.95. The reason of laser shooting experiments operated at 0.5Hz rather than 1Hz is because the synchronization between the nano-foil target positioning system and the laser trigger needs to improve.DFG Cluster of Excellence Munich-Centre for Advanced Photonics (MAP); Centre for Advanced Laser Applications; China Scholarship [201508080084]SCI(E)ARTICLE
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