The role of ν\nu-induced reactions on lead and iron in neutrino detectors

We have calculated cross sections and branching ratios for neutrino induced reactions on ^{208}Pb and ^{56}Fe for various supernova and accelerator-relevant neutrino spectra. This was motivated by the facts that lead and iron will be used on one hand as target materials in future neutrino detectors, on the other hand have been and are still used as shielding materials in accelerator-based experiments. In particular we study the inclusive ^{56}$Fe(\nu_e,e^-)$^{56}Co and ^{208}$Pb(\nu_e,e^-)$^{208}Bi cross sections and calculate the neutron energy spectra following the decay of the daughter nuclei. These reactions give a potential background signal in the KARMEN and LSND experiment and are discussed as a detection scheme for supernova neutrinos in the proposed OMNIS and LAND detectors. We also study the neutron-emission following the neutrino-induced neutral-current excitation of ^{56}Fe and ^{208}Pb.Comment: 23 pages (including 7 figures

Muon capture on nuclei with N > Z, random phase approximation, and in-medium renormalization of the axial-vector coupling constant

We use the random phase approximation to describe the muon capture rate on ${}^{44}$Ca,${}^{48}$Ca, ${}^{56}$Fe, ${}^{90}$Zr, and ${}^{208}$Pb. With ${}^{40}$Ca as a test case, we show that the Continuum Random Phase Approximation (CRPA) and the standard RPA give essentially equivalent descriptions of the muon capture process. Using the standard RPA with the free nucleon weak form factors we reproduce the experimental total capture rates on these nuclei quite well. Confirming our previous CRPA result for the $N = Z$ nuclei, we find that the calculated rates would be significantly lower than the data if the in-medium quenching of the axial-vector coupling constant were employed.Comment: submitted to Phys. Rev.

Signal for supernova νμ\nu_\mu and ντ\nu_\tau neutrinos in water \v{C}erenkov detectors

We suggest that photons with energies between 5 and 10 MeV, generated by the ($\nu,\nu'p\gamma$) and ($\nu,\nu'n\gamma$) reactions on $^{16}$O, constitute a signal which allows a unique identification of supernova $\nu_\mu$ and $\nu_\tau$ neutrinos in water \v{C}erenkov detectors. We calculate the yield of such $\gamma$ events and estimate that a few hundred of them would be detected in Superkamiokande for a supernova at 10 kpc distance.Comment: 8 pages, RevTex 3.0, figures and text available at http://www.krl.caltech.edu/preprints/MAP.htm

"Be active!" Revisiting the South African Food Based Dietary Guidelines for activity

The objective of this paper was to review current evidence on physical activity for health in order to support the foodbased dietary guideline (FBDG) “Be active!”. Physical activity, defined as at least 30 minutes of moderate-intensity physical activity per day for adults, and 60 minutes for children and adolescents, is advised in the FBDG because of the role it plays in maintaining energy balance, improving body composition and promoting general health and wellbeing. The reviewed outcome measures are changes in physical activity patterns and the reported prevalence of noncommunicable diseases (NCDs) in South Africa. Despite the previous set of FBDGs, no improvements in physical activity, obesity or NCDs have been reported in South Africa. Recent literature emphasises the beneficial effects of physical activity on the reduction of risk factors associated with the prevalence of NCDs. Physical activity has a positive effect on appetite and weight control, insulin sensitivity, dyslipidaemia, hypertension, stress relief and burnout. Barriers that prevent children and adults from participating in regular physical activity have been identified, and recommendations how to overcome these have been made. It has been concluded that South Africans are not sufficiently physically active for their general health status to be improved. It is recommended that methods to promote physical activity at national, provincial, district and local level need to be developed, implemented and sustained

Neutrino induced transitions between the ground states of the A=12 triad

Neutrino induced reactions on $^{12}$C, an ingredient of liquid scintillators, have been studied in several experiments. We show that for currently available neutrino energies, $E_{\nu} \le$ 300 MeV, calculated exclusive cross sections $^{12}$C$_{gs}(\nu,l)$$^{12}$N$_{gs}$ 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

Strangeness in the nucleon and the ratio of proton-to-neutron neutrino-induced quasi-elastic yield

The electroweak form factors of the nucleon as obtained within a three flavor pseudoscalar vector meson soliton model are employed to predict the ratio of the proton and neutron yields from $^{12}C$, which are induced by quasi-elastic neutrino reactions. These predictions are found to vary only moderately in the parameter space allowed by the model. The antineutrino flux of the up-coming experiment determining this ratio was previously overestimated. The corresponding correction is shown to have only a small effect on the predicted ratio. However, it is found that the experimental result for the ratio crucially depends on an accurate measurement of the energy of the knocked out nucleon.Comment: 17 pages, LaTeX, 2 tables, 4 figures, Discussion on shape of strange form factors added, Z. Phys. A, to be publishe

Signatures of Nucleon Disappearance in Large Underground Detectors

For neutrons bound inside nuclei, baryon instability can manifest itself as a decay into undetectable particles (e.g., $\it n \to \nu \nu \bar{\nu}$), i.e., as a disappearance of a neutron from its nuclear state. If electric charge is conserved, a similar disappearance is impossible for a proton. The existing experimental lifetime limit for neutron disappearance is 4-7 orders of magnitude lower than the lifetime limits with detectable nucleon decay products in the final state [PDG2000]. In this paper we calculated the spectrum of nuclear de-excitations that would result from the disappearance of a neutron or two neutrons from $^{12}$C. We found that some de-excitation modes have signatures that are advantageous for detection in the modern high-mass, low-background, and low-threshold underground detectors, where neutron disappearance would result in a characteristic sequence of time- and space-correlated events. Thus, in the KamLAND detector [Kamland], a time-correlated triple coincidence of a prompt signal, a captured neutron, and a $\beta^{+}$ decay of the residual nucleus, all originating from the same point in the detector, will be a unique signal of neutron disappearance allowing searches for baryon instability with sensitivity 3-4 orders of magnitude beyond the present experimental limits.Comment: 13 pages including 6 figures, revised version, to be published in Phys.Rev.

Weak and Electromagnetic Nuclear Decay Signatures for Neutrino Reactions in SuperKamiokande

We suggest the study of events in the SuperKamiokande neutrino data due to charged- and neutral-current neutrino reactions followed by weak and/or electromagnetic decays of struck nuclei and fragments thereof. This study could improve the prospects of obtaining evidence for $\tau$ production from $\nu_\mu \to \nu_\tau$ oscillations and could augment the data sample used to disfavor $\nu_\mu \to \nu_{sterile}$ oscillations.Comment: 7 pages, latex, to appear in Phys. Rev. Let

'Be active!' Revisiting the South African food-based dietary guideline for activity

The objective of this paper was to review current evidence on physical activity for health in order to support the food-based dietary guideline (FBDG) “Be active!”. Physical activity, defined as at least 30 minutes of moderate-intensity physical activity per day for adults, and 60 minutes for children and adolescents, is advised in the FBDG because of the role it plays in maintaining energy balance, improving body composition and promoting general health and wellbeing. The reviewed outcome measures are changes in physical activity patterns and the reported prevalence of noncommunicable diseases (NCDs) in South Africa. Despite the previous set of FBDGs, no improvements in physical activity, obesity or NCDs have been reported in South Africa. Recent literature emphasises the beneficial effects of physical activity on the reduction of risk factors associated with the prevalence of NCDs. Physical activity has a positive effect on appetite and weight control, insulin sensitivity, dyslipidaemia, hypertension, stress relief and burnout. Barriers that prevent children and adults from participating in regular physical activity have been identified, and recommendations how to overcome these have been made. It has been concluded that South Africans are not sufficiently physically active for their general health status to be improved. It is recommended that methods to promote physical activity at national, provincial, district and local level need to be developed, implemented and sustained

Assessing the validity and reliability and determining cut-points of the Actiwatch 2 in measuring physical activity

Objective: The Actiwatch 2 (AW2) is a wrist-worn accelerometer typically used to measure sleep. Although it can measure physical activity, there is limited evidence supporting its validity. We assessed the validity and reliability of the AW2 to measure sedentary behavior and physical activity (light, moderate, vigorous intensities), and reported their respective count cut-points. Approach: Twenty-eight males and 22 females completed a task battery comprising three sedentary tasks and six randomized physical activity tasks at varying intensities, whilst wearing the AW2, a reference accelerometry device (Actigraph GT3X) and a cardiopulmonary gas analyzer on two separate occasions. Validity was assessed using correlations (AW2 counts versus GT3X counts and metabolic equivalent (MET) values), reliability using Bland–Altman analyses, and cut-points were determined using receiver operating characteristic (ROC) area under the curve (AUC) analyses. Main results: AW2 counts were positively correlated with GT3X counts (rho = 0.902, p < 0.001) and METs (rho = 0.900, p < 0.001). AW2-derived counts were comparable across independent assessment periods. Sedentary (AUC = 0.99, cut-point: 256 cpm) and vigorous activity (AUC = 0.95, cut-point: 720 cpm) were strongly characterized, and moderate activity (AUC = 0.66, cut-point: 418 cpm) was weakly characterized. Significance: The use of the AW2 in physical activity monitoring looks promising for sedentary behavior, moderate and vigorous activity, however, further validation is needed