Prompt identification of the warning signs of ischemic stroke is critical to ensure appropriate and timely treatment. We implemented a 20-week public education campaign in one media market to ...increase community awareness of warning signs for stroke and the need to call 911. Telephone surveys were conducted in adults aged 45 years and older in the intervention county and a comparison county before and after the campaign to evaluate its impact. There was a significant increase in awareness of two or more warning signs for stroke from baseline to follow-up in the intervention county (73%-82%) but not in the comparison county (68%-69%). Respondent awareness of stroke warning signs increased significantly in the intervention county among men (68%-79%) and women (76%-84%) and among respondents aged 45 to 64 years (77%-85%) and respondents aged 65 years and older (67%-78%). There was no significant change in the proportion of respondents indicating they would call 911 if they witnessed someone having a stroke in the intervention county (81%-84%). However, after the campaign, an increased proportion of respondents in the intervention county indicated they would call 911 if they experienced sudden numbness or loss of sensation (50%-56%). Our findings suggest that a high-intensity public education campaign can increase community awareness of the warning signs for stroke and the need to call 911 for specific symptoms.
Neutrons produced in nuclear interactions initiated by cosmic-ray muons present an irreducible background to many rare-event searches, even in detectors located deep underground. Models for the ...production of these neutrons have been tested against previous experimental data, but the extrapolation to deeper sites is not well understood. Here we report results from an analysis of cosmogenically produced neutrons at the Sudbury Neutrino Observatory. A specific set of observables are presented, which can be used to benchmark the validity of geant4 physics models. In addition, the cosmogenic neutron yield, in units of 10−4 cm2/(g·μ), is measured to be 7.28±0.09(stat)−1.12+1.59(syst) in pure heavy water and 7.30±0.07(stat)−1.02+1.40(syst) in NaCl-loaded heavy water. These results provide unique insights into this potential background source for experiments at SNOLAB.
Neutron production in giga electron volt–scale neutrino interactions is a poorly studied process. We have measured the neutron multiplicities in atmospheric neutrino interactions in the Sudbury ...Neutrino Observatory experiment and compared them to the prediction of a Monte Carlo simulation using genie and a minimally modified version of geant4. We analyzed 837 days of exposure corresponding to Phase I, using pure heavy water, and Phase II, using a mixture of Cl in heavy water. Neutrons produced in atmospheric neutrino interactions were identified with an efficiency of 15.3% and 44.3%, for Phases I and II respectively. The neutron production is measured as a function of the visible energy of the neutrino interaction and, for charged current quasielastic interaction candidates, also as a function of the neutrino energy. This study is also performed by classifying the complete sample into two pairs of event categories: charged current quasielastic and non charged current quasielastic, and νμ and νe. Results show good overall agreement between data and Monte Carlo for both phases, with some small tension with a statistical significance below 2σ for some intermediate energies.
Future direct searches for low-mass dark matter particles with germanium detectors, such as SuperCDMS SNOLAB, are expected to be limited by backgrounds from radioactive isotopes activated by ...cosmogenic radiation inside the germanium. There are limited experimental data available to constrain production rates and a large spread of theoretical predictions. We examine the calculation of expected production rates, and analyze data from the second run of the CDMS low ionization threshold experiment (CDMSlite) to estimate the rates for several isotopes. We model the measured CDMSlite spectrum and fit for contributions from tritium and other isotopes. Using the knowledge of the detector history, these results are converted to cosmogenic production rates at sea level. The production rates in atoms/(kg · day) are 74 ± 9 for 3H, 1.5 ± 0.7 for 55Fe, 17 ± 5 for 65Zn, and 30 ± 18 for 68Ge.
Background Rural–urban gaps in stroke care remain challenging in part because of the lack of resources, personnel, and necessary infrastructure. Purpose The purpose of this study was to assess ...changes in the acute stroke diagnosis and treatment capacity among rural hospitals before and after implementation of a regionwide stroke initiative. Methods In 2004, the Montana Cardiovascular Health Program partnered with stroke stakeholders throughout the state and surveyed hospitals in Montana and northern Wyoming to assess the availability of technology, services, and personnel for acute stroke care. The Montana Stroke Initiative (MSI) developed protocols, educational material, and stroke awareness campaigns to address the geographic disparities identified in the survey. From 2004 to 2006, protocols and educational material were made available on a website and distributed to rural and critical-access hospitals throughout the region. Stroke awareness campaigns were completed, and MSI members conducted acute stroke care training of prehospital, nursing, and primary providers throughout the region. A follow-up survey in 2008 assessed changes in the stroke systems of care between 2004 and 2008. Data were analyzed in 2009. Results There were significant increases in availability of prehospital stroke screens, written emergency department protocols, computed tomographic scanning capability, acute stroke teams, and community stroke awareness programs. Conclusions A systematic statewide effort to improve stroke care led to improved acute stroke care capabilities in necessary infrastructure in rural facilities and a narrowing of the gap between these facilities and the urban facilities.
We present a new analysis of previously published SuperCDMS data using a profile likelihood framework to search for sub-GeV dark matter (DM) particles through two inelastic scattering channels: ...bremsstrahlung radiation and the Migdal effect. By considering these possible inelastic scattering channels, experimental sensitivity can be extended to DM masses that are undetectable through the DM-nucleon elastic scattering channel, given the energy threshold of current experiments. We exclude DM masses down to 220 MeV/c2 at 2.7 x 10-30 cm2 via the bremsstrahlung channel. The Migdal channel search provides overall considerably more stringent limits and excludes DM masses down to 30 MeV/ c2 at 5.0 x 10-30 cm2.
New data from the T2K neutrino oscillation experiment produce the most precise measurement of the neutrino mixing parameter theta_{23}. Using an off-axis neutrino beam with a peak energy of 0.6 GeV ...and a data set corresponding to 6.57 x 10^{20} protons on target, T2K has fit the energy-dependent nu_mu oscillation probability to determine oscillation parameters. Marginalizing over the values of other oscillation parameters yields sin^2 (theta_{23}) = 0.514 +0.055/-0.056 (0.511 +- 0.055), assuming normal (inverted) mass hierarchy. The best-fit mass-squared splitting for normal hierarchy is Delta m^2_{32} = 2.51 +- 0.10 x 10^{-3} eV^2/c^4 (inverted hierarchy: Delta m^2_{13} = 2.48 +- 0.10 x 10^{-3} eV^2/c^4). Adding a model of multinucleon interactions that affect neutrino energy reconstruction is found to produce only small biases in neutrino oscillation parameter extraction at current levels of statistical uncertainty.
The long baseline between Earth and the Sun makes solar neutrinos an excellent test beam for exploring possible neutrino decay. The signature of such decay would be an energy-dependent distortion of ...the traditional survival probability which can be fit for using well-developed and high-precision analysis methods. Here a model including neutrino decay is fit to all three phases of $^{8}\mathrm{B}$ solar neutrino data taken by the Sudbury Neutrino Observatory (SNO). This fit constrains the lifetime of neutrino mass state ${{\nu}}_{2}$ to be > $8.08\times{}{10}^{{-}5}\text{ }\text{ }\mathrm{s}/\mathrm{eV}$ at 90% confidence. An analysis combining this SNO result with those from other solar neutrino experiments results in a combined limit for the lifetime of mass state ${{\nu}}_{2}$ of > $1.92\times{}{10}^{{-}3}\text{ }\text{ }\mathrm{s}/\mathrm{eV}$ at 90% confidence.
We report measurements by the T2K experiment of the parameters θ23 and Δm322 governing the disappearance of muon neutrinos and antineutrinos in the three-flavor neutrino oscillation model. Utilizing ...the ability of the experiment to run with either a mainly neutrino or a mainly antineutrino beam, the parameters are measured separately for neutrinos and antineutrinos. Using 7.482×1020 POT in neutrino running mode and 7.471×1020 POT in antineutrino mode, T2K obtained sin2(θ23)=0.51−0.07+0.08 and Δm322=2.53−0.13+0.15×10−3 eV2/c4 for neutrinos, and sin2(θ¯23)=0.42−0.07+0.25 and Δm¯232=2.55−0.27+0.33×10−3 eV2/c4 for antineutrinos (assuming normal mass ordering). No significant differences between the values of the parameters describing the disappearance of muon neutrinos and antineutrinos were observed.
This paper reports the first differential measurement of the charged-current interaction cross section of νμ on water with no pions in the final state. This flux-averaged measurement has been made ...using the T2K experiment’s off-axis near detector, and is reported in doubly differential bins of muon momentum and angle. The flux-averaged total cross section in a restricted region of phase space was found to be σ=(0.95±0.08(stat)±0.06(det syst)±0.04(model syst)±0.08(flux))×10−38 cm2/n.
PDF
