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

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

Nucleation and phase selection in undercooled melts: Magnetic alloys of industrial relevance (MAGNEPHAS)

Studies of phase selection and microstructure evolution in high-performance magnetic materials are an urgent need for optimization of production routes. Containerless solidification experiments by electromagnetic levitation and drop tube solidification were conducted in undercooled melts of Fe-Co, Fe-Ni soft magnetic, and Nd-Fe-B hard magnetic alloys. Melt undercooling under microgravity was achieved in the TEMPUS facility during parabolic flight campaigns. For Fe-Co and Fe-Ni alloys significant effects of microgravity on metastable phase formation were discovered. Microstructure modifications as well as metastable phase formation as function of undercooling and melt flow were elucidated in Nd-Fe-B. Modeling of solidification processes, fluid flow and heat transfer provide predictive tools for microstructure engineering from the melt. They were developed as a link between undercooling experiments under terrestrial and microgravity conditions and the production routes of magnetic materials

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

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

A Comparison of the Population Genetic Structure and Diversity between a Common (\u3cem\u3eChrysemys p. picta\u3c/em\u3e) and an Endangered (\u3cem\u3eClemmys guttata\u3c/em\u3e) Freshwater Turtle

The northeastern United States has experienced dramatic alteration to its landscape since the time of European settlement. This alteration has had major impacts on the distribution and abundance of wildlife populations, but the legacy of this landscape change remains largely unexplored for most species of freshwater turtles. We used microsatellite markers to characterize and compare the population genetic structure and diversity between an abundant generalist, the eastern painted turtle (Chrysemys p. picta), and the rare, more specialized, spotted turtle (Clemmys guttata) in Rhode Island, USA. We predicted that because spotted turtles have disproportionately experienced the detrimental effects of habitat loss and fragmentation associated with landscape change, that these effects would manifest in the form of higher inbreeding, less diversity, and greater population genetic structure compared to eastern painted turtles. As expected, eastern painted turtles exhibited little population genetic structure, showed no evidence of inbreeding, and little differentiation among sampling sites. For spotted turtles, however, results were consistent with certain predictions and inconsistent with others. We found evidence of modest inbreeding, as well as tentative evidence of recent population declines. However, genetic diversity and differentiation among sites were comparable between species. As our results do not suggest any major signals of genetic degradation in spotted turtles, the southern region of Rhode Island may serve as a regional conservation reserve network, where the maintenance of population viability and connectivity should be prioritized

Measurements of Charged Current Reactions of νe\nu_e on 12C^{12}C

Charged Current reactions of $\nu_e$ on $^{12}C$ have been studied using a $\mu^+$ decay-at-rest $\nu_e$ beam at the Los Alamos Neutron Science Center. The cross section for the exclusive reaction $^{12}C(\nu_e,e^-)^{12}N_{g.s.}$ was measured to be $(8.9\pm0.3\pm0.9)\times10^{-42}$ cm$^2$. The observed energy dependence of the cross section and angular distribution of the outgoing electron agree well with theoretical expectations. Measurements are also presented for inclusive transitions to $^{12}N$ excited states, $^{12}C(\nu_e,e^-)^{12}N^*$ and compared with theoretical expectations. The measured cross section, $(4.3\pm0.4\pm0.6)\times10^{-42}$ cm$^2$, is somewhat lower than previous measurements and than a continuum random phase approximation calculation. It is in better agreement with a recent shell model calculation.Comment: 34 pages, 18 figures, accepted to PRC, replaced with the accepted on

Visual Attention of Anesthesia Providers in Simulated Anesthesia Emergencies Using Conventional Number-Based and Avatar-Based Patient Monitoring: Prospective Eye-Tracking Study

Background: Inadequate situational awareness accounts for two-thirds of preventable complications in anesthesia. An essential tool for situational awareness in the perioperative setting is the patient monitor. However, the conventional monitor has several weaknesses. Avatar-based patient monitoring may address these shortcomings and promote situation awareness, a prerequisite for good decision making. Objective: The spatial distribution of visual attention is a fundamental process for achieving adequate situation awareness and thus a potential quantifiable surrogate for situation awareness. Moreover, measuring visual attention with a head-mounted eye-tracker may provide insights into usage and acceptance of the new avatar-based patient monitoring modality. Methods: This prospective eye-tracking study compared anesthesia providers' visual attention on conventional and avatar-based patient monitors during simulated critical anesthesia events. We defined visual attention, measured as fixation count and dwell time, as our primary outcome. We correlated visual attention with the potential confounders: performance in managing simulated critical anesthesia events (task performance), work experience, and profession. We used mixed linear models to analyze the results. Results: Fifty-two teams performed 156 simulations. After a manual quality check of the eye-tracking footage, we excluded 57 simulations due to technical problems and quality issues. Participants had a median of 198 (IQR 92.5-317.5) fixations on the patient monitor with a median dwell time of 30.2 (IQR 14.9-51.3) seconds. We found no significant difference in participants' visual attention when using avatar-based patient monitoring or conventional patient monitoring. However, we found that with each percentage point of better task performance, the number of fixations decreased by about 1.39 (coefficient -1.39; 95% CI -2.44 to -0.34; P=.02), and the dwell time diminished by 0.23 seconds (coefficient -0.23; 95% CI: -0.4 to -0.06; P=.01). Conclusions: Using eye tracking, we found no significant difference in visual attention when anesthesia providers used avatar-based monitoring or conventional patient monitoring in simulated critical anesthesia events. However, we identified visual attention in conjunction with task performance as a surrogate for situational awareness. Keywords: Anesthesia; avatar based model; eye-tracking technology; patient monitoring; patient simulation; perioperative; simulated anesthesia; situation awareness; task performance; visual attention