Measurement of Neutral-Current K

Neutral-current production of K^{+} by atmospheric neutrinos is a background in searches for the proton decay p→K^{+}ν[over ¯]. Reactions such as νp→νK^{+}Λ are indistinguishable from proton decays when the decay products of the Λ are below detection threshold. Events with K^{+} are identified in MINERvA by reconstructing the timing signature of a K^{+} decay at rest. A sample of 201 neutrino-induced neutral-current K^{+} events is used to measure differential cross sections with respect to the K^{+} kinetic energy, and the non-K^{+} hadronic visible energy. An excess of events at low hadronic visible energy is observed relative to the prediction of the neut event generator. Good agreement is observed with the cross section prediction of the genie generator. A search for photons from π^{0} decay, which would veto a neutral-current K^{+} event in a proton decay search, is performed, and a 2σ deficit of detached photons is observed relative to the genie prediction.

Evidence for Neutral-Current Diffractive π

The MINERvA experiment observes an excess of events containing electromagnetic showers relative to the expectation from Monte Carlo simulations in neutral-current neutrino interactions with mean beam energy of 4.5 GeV on a hydrocarbon target. The excess is characterized and found to be consistent with neutral-current π^{0} production with a broad energy distribution peaking at 7 GeV and a total cross section of 0.26±0.02(stat.)±0.08(sys.)×10^{-39} cm^{2}. The angular distribution, electromagnetic shower energy, and spatial distribution of the energy depositions of the excess are consistent with expectations from neutrino neutral-current diffractive π^{0} production from hydrogen in the hydrocarbon target. These data comprise the first direct experimental observation and constraint for a reaction that poses an important background process in neutrino-oscillation experiments searching for ν_{µ} to ν_{e} oscillations.

Evidence of Coherent K

Neutrino-induced charged-current coherent kaon production ν_{µ}A→µ^{-}K^{+}A is a rare, inelastic electroweak process that brings a K^{+} on shell and leaves the target nucleus intact in its ground state. This process is significantly lower in rate than the neutrino-induced charged-current coherent pion production because of Cabibbo suppression and a kinematic suppression due to the larger kaon mass. We search for such events in the scintillator tracker of MINERvA by observing the final state K^{+}, µ^{-}, and no other detector activity, and by using the kinematics of the final state particles to reconstruct the small momentum transfer to the nucleus, which is a model-independent characteristic of coherent scattering. We find the first experimental evidence for the process at 3σ significance.

Decongestant effects on hemodynamics at rest, exercise, and recovery from exercise during--6 degrees of head down tilt.

HYPOTHESIS: Ten males were studied to examine the effects of a decongestant, pseudoephedrine hydrochloride, on rest, exercise, and recovery from exercise during -6 degrees of head down tilt (HDT). METHODS: Subjects were positioned in the HDT for a total of 6 hr: 2 hr 45 min rest, 30 min exercise, and 2 hr 45 min recovery. Sessions were identical except for the ingestion of a drug or placebo. Variables evaluated during rest, exercise, and recovery conditions were: systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), stroke volume (SV), cardiac output (Q), pulse pressure (PP), mean arterial pressure (MAP), total peripheral resistance (TPR), and forearm blood flow (FBF). RESULTS: During rest PP at 120 min was less than resting baseline, and MAP increased throughout rest. There was a treatment effect for SBP which increased up to 90 min from resting baseline for the placebo treatment only. Normal changes were found with exercise, with all variables increasing above baseline except for TPR which decreased. DBP showed no change during exercise. During the recovery condition for the drug treatment HR decreased, while SBP increased from 30 min. In addition, DBP and MAP were higher for the placebo at 30 min and higher for the drug at 90 min. CONCLUSION: The results show that ingestion of the sympathomimetic agent pseudoephedrine hydrochloride has no significant effects on the cardiovascular system during simulated microgravity.

The effect of submaximal exercise on recovery hemodynamics and thermoregulation in men and women.

Five women and 5 men were studied to examine the effects of submaximal exercise on thermoregulatory and hemodynamic variables during recovery in two environments: (a) control (C), 22 degrees C, 33% rh; and (b) hot humid (H), 32 degrees C. The participants exercised on a cycle ergometer at 60% of peak oxygen consumption for 35 min prior to 90 min of seated recovery. Sessions were identical, except for environment. Variables evaluated (p < .05) were: core temperature (TR), mean skin temperature (Ts), sweat rate (SR), heart rate (HR), stroke index (SI), cardiac index (CI), forearm blood flow (FBF), systolic blood pressure (SBP), and diastolic blood pressure (DBP). Men and women exhibited similar patterns of TR, Ts, and SR in both environments. Ts and SR (collapsed means for gender) were higher in the H than in the C. DBP was higher in men than in women throughout recovery in both environments. With combined means for gender, HR was higher in the H than in the C. CI, SI, FBF, and SBP were similar in both environments and returned to baseline within 15 min into recovery. These data suggest that heat dissipation during extended recovery was accomplished with similar contributions of cutaneous vasodilation and sweating in M and F. Furthermore, the moderate exercise level did not influence hemodynamics beyond 15 min of recovery in either environment.

Thermogenesis during rest and exercise in cold air.

Nine non-cold-acclimated subjects (5 female, 4 male, mean age 22.5 years) were studied to determine whether nonshivering thermogenesis contributes to cold-induced metabolic heat production during rest (50 min standing) and exercise (40 min treadmill walking) in 5 degrees C. Propranolol was administered orally (females, 60 mg, 1.12 mg.kg-1; males, 80 mg, 0.96 mg.kg-1) to block nonshivering thermogenesis. Measurements were taken at both 25 degrees C, 13.1 Torr (water vapor pressure; 1 Torr = 133.3 Pa) and 5 degrees C, 3.6 Torr, with sessions randomly assigned to be drug-neutral (DN), drug-cold (DC), placebo-neutral (PN), and placebo-cold (PC). Body core temperature was not different between any of the experimental conditions. Mean body temperature (5 degrees C, 32.2 +/- 0.20 degrees C (+/- SEM); 25 degrees C, 35.3 +/- 0.20 degrees C) and mean skin temperature (5 degrees C, 22.4 +/- 0.70 degrees C; 25 degrees C, 31.4 +/- 0.60 degrees C) were lower (p < 0.05) in the 5 degrees C than 25 degrees C environment (rest, exercise, drug (D), placebo (P), combined); while shivering (EMG) was higher (16.5 +/- 3.9% above baseline) at 5 degrees C than 25 degrees C (15 +/- 2.1% below baseline) (p < 0.05). The greater VO2 in 5 degrees C compared with 25 degrees C for the same condition is the thermoregulatory VO2 (TVO2). TVO2 (mL.min-1) was lower (p < 0.05) on the D (mean = 189.5 +/- 17.7) than on the P (mean = 238.1 +/- 20.2) during rest and during exercise (D, 206.1 +/- 63.7; P, 338.4 +/- 46.7). The EMG was 21% above baseline in the DC, and 12% above baseline for PC (p > 0.05). These results suggest a nonshivering component to heat production during acute cold exposure, which can be blocked with propranolol.

Patterns of cytomegalovirus retinitis in immunocompromised patients treated with 9-(2-hydroxy-1-(hydroxymethyl)ethoxymethyl) guanine (ganciclovir).

Five immunocompromised patients, four with AIDS and one who had undergone bone marrow transplantation, showing ocular signs of cytomegalovirus retinitis, were treated with 9-(2-hydroxy-1-(hydroxymethyl)ethoxymethyl) guanine (Ganciclovir), given intravenously at the dose of 5 mg/kg twice daily for a period ranging from 10 to 20 days. At the end of the treatment, in 4 of 5 patients, the ophthalmoscopic picture had improved, with reduced exudation and an arrest in the progression of retinal necrosis, the pattern clearly indicating a trend towards organization and scarring. Complete resolution of the retinitis without subsequent relapse was observed only in the bone marrow transplant patient, who recovered immunologically, whereas improvement of the eye involvement was only transient in the three AIDS patients.