MiniBooNE and MicroBooNE Combined Fit to a 3+1 Sterile Neutrino Scenario.

This Letter presents the results from the MiniBooNE experiment within a full "3+1" scenario where one sterile neutrino is introduced to the three-active-neutrino picture. In addition to electron-neutrino appearance at short baselines, this scenario also allows for disappearance of the muon-neutrino and electron-neutrino fluxes in the Booster Neutrino Beam, which is shared by the MicroBooNE experiment. We present the 3+1 fit to the MiniBooNE electron-(anti)neutrino and muon-(anti)neutrino data alone and in combination with MicroBooNE electron-neutrino data. The best-fit parameters of the combined fit with the exclusive charged-current quasielastic analysis (inclusive analysis) are Δm^{2}=0.209 eV^{2}(0.033 eV^{2}), |U_{e4}|^{2}=0.016(0.500), |U_{µ4}|^{2}=0.500(0.500), and sin^{2}(2θ_{µe})=0.0316(1.0). Comparing the no-oscillation scenario to the 3+1 model, the data prefer the 3+1 model with a Δχ^{2}/d.o.f.=24.7/3(17.3/3), a 4.3σ(3.4σ) preference assuming the asymptotic approximation given by Wilks's theorem.

Significant Excess of Electronlike Events in the MiniBooNE Short-Baseline Neutrino Experiment.

The MiniBooNE experiment at Fermilab reports results from an analysis of ν_{e} appearance data from 12.84×10^{20} protons on target in neutrino mode, an increase of approximately a factor of 2 over previously reported results. A ν_{e} charged-current quasielastic event excess of 381.2±85.2 events (4.5σ) is observed in the energy range 200

First Measurement of Monoenergetic Muon Neutrino Charged Current Interactions.

We report the first measurement of monoenergetic muon neutrino charged current interactions. MiniBooNE has isolated 236 MeV muon neutrino events originating from charged kaon decay at rest (K^{+}→µ^{+}ν_{µ}) at the NuMI beamline absorber. These signal ν_{µ}-carbon events are distinguished from primarily pion decay in flight ν_{µ} and ν[over ¯]_{µ} backgrounds produced at the target station and decay pipe using their arrival time and reconstructed muon energy. The significance of the signal observation is at the 3.9σ level. The muon kinetic energy, neutrino-nucleus energy transfer (ω=E_{ν}-E_{µ}), and total cross section for these events are extracted. This result is the first known-energy, weak-interaction-only probe of the nucleus to yield a measurement of ω using neutrinos, a quantity thus far only accessible through electron scattering.

Dark Matter Search in a Proton Beam Dump with MiniBooNE.

The MiniBooNE-DM Collaboration searched for vector-boson mediated production of dark matter using the Fermilab 8-GeV Booster proton beam in a dedicated run with 1.86×10^{20} protons delivered to a steel beam dump. The MiniBooNE detector, 490 m downstream, is sensitive to dark matter via elastic scattering with nucleons in the detector mineral oil. Analysis methods developed for previous MiniBooNE scattering results were employed, and several constraining data sets were simultaneously analyzed to minimize systematic errors from neutrino flux and interaction rates. No excess of events over background was observed, leading to a 90% confidence limit on the dark matter cross section parameter, Y=ε^{2}α_{D}(m_{χ}/m_{V})^{4}≲10^{-8}, for α_{D}=0.5 and for dark matter masses of 0.01

Lower-extremity muscle atrophy and fat infiltration after chronic spinal cord injury.

BACKGROUND: Atrophy and fatty-infiltration of lower-extremity muscle after spinal cord injury (SCI) predisposes individuals to metabolic disease and related mortality. OBJECTIVES: To determine the magnitude of atrophy and fatty-infiltration of lower-extremity muscles and related factors in a group of individuals with chronic SCI and diverse impairment. METHODS: Muscle cross-sectional area and density were calculated from peripheral quantitative computed tomography scans of the 66% site of the calf of 70 participants with chronic SCI [50 male, mean age 49 (standard deviation 12) years, C2-T12, AIS A-D] and matched controls. Regression models for muscle area and density were formed using 16 potential correlates selected a priori. RESULTS: Participants with motor-complete SCI had ≈ 32% lower muscle area, and ≈ 43% lower muscle density values relative to controls. Participants with motor-incomplete SCI had muscle area and density values that were both ≈ 14% lower than controls. Body mass (+), tetraplegia (+), motor function (+), spasticity (+), vigorous physical activity (+), wheelchair use (-), age (-), and waist circumference (-) were associated with muscle size and/or density in best-fit regression models. CONCLUSIONS: There are modifiable factors related to muscle size, body composition, and activity level that may offer therapeutic targets for preserving metabolic health after chronic SCI.

Improved search for ν¯(µ)→ν¯(e) oscillations in the MiniBooNE experiment.

The MiniBooNE experiment at Fermilab reports results from an analysis of ν[over ¯](e) appearance data from 11.27×10(20) protons on target in the antineutrino mode, an increase of approximately a factor of 2 over the previously reported results. An event excess of 78.4±28.5 events (2.8σ) is observed in the energy range 200

Event excess in the MiniBooNE search for ¯νµâ†’¯νe oscillations.

The MiniBooNE experiment at Fermilab reports results from a search for ¯ν_{µ}→¯ν_{e} oscillations, using a data sample corresponding to 5.66×10²° protons on target. An excess of 20.9±14.0 events is observed in the energy range 475

Intracellular pH (pHi) in gastric surface epithelium is more susceptible to serosal than mucosal acidification.

Intracellular microelectrode techniques were used to examine the effects of mucosal or serosal acidification on intracellular pH (pHi) in gastric surface epithelial cells. Necturus antrum was mounted in a modified Ussing chamber, and pHi was determined from the difference between the potentials recorded by intracellular conventional and pH-sensitive microelectrodes. In tissues bathed with bicarbonate-buffered Ringer's solution (pH 7), acidification of the mucosal solution to pH 4.5 by isotonic replacement of the NaHCO3 with NaCl had no significant effects on pHi. In contrast, acidification of the serosal solution to pH 4.5 by replacing the bicarbonate reduced pHi from 7.32 +/- 0.04 to 6.95 +/- 0.06 (p less than 0.001, n = 8). Similarly, in tissues bathed with HEPES-buffered Ringer's solution (pH 7.0), pHi was unaffected by reducing the mucosal solution pH to 4.5 with HCl but fell 0.21 +/- 0.05 pH units (p less than 0.01, n = 7) during acidification of the serosal solution to pH 6. These results suggest that gastric epithelium is more sensitive to acidification from the serosal than the mucosal side. Such a finding is consistent with the concept of a gastric mucosal barrier to luminal acid. It may also explain the gastric epithelium's greater sensitivity to acute ulceration during systemic acidosis.

Effects of aspirin and acetic acid on intracellular pH in necturus gastric mucosa.

Intracellular microelectrode techniques were employed to examine the effects of luminal aspirin and acetic acid on intracellular pH and cell membrane potential in the surface epithelial cells of Necturus antrum. Antral mucosa was mounted in a modified Ussing chamber, and intracellular pH was determined from the difference between the potentials recorded by intracellular conventional and pH-sensitive microelectrodes. Under neutral conditions (pH7), aspirin (5 mM) hyperpolarized (-7.5 +/- 1 mV, p less than 0.0001) and acetic acid (5 mM) depolarized (+4 +/- 0.08 mV, p less than 0.001) cell membrane potential. Neither agent had any significant effect on intracellular pH. Under acidic conditions (pH 4.5), aspirin (5 mM) reduced the intracellular pH from 6.99 +/- 0.03 to 6.87 +/- 0.04 (p less than 0.001) and depolarized cell membrane potential from -36.7 +/- 1.5 to -30.3 +/- 1.6 mV, p less than 0.001). Similarly, acetic acid (5 mM) acidified the cells (-0.20 +/- 0.02, p less than 0.001) and depolarized cell membrane potential (+9.6 +/- 1.9 mV, p less than 0.01). These changes suggest that, in the absence of luminal acid, small organic acids, such as aspirin and acetic acid, may have complex effects on the ionic conductances of the surface cell membranes without altering intracellular pH. In contrast, under acidic conditions, these agents increase the permeability of the apical cell membrane-to-acid back-diffusion from the gastric lumen.

Spatial inhibition and the visual cortex: a magnetic resonance spectroscopy imaging study.

INTRODUCTION: Deficits in processing spatial information have been observed in clinical populations who have abnormalities within the dopamine (DA) system. As psychostimulants such as methamphetamine (MA) are particularly neurotoxic to the dopaminergic system it was of interest to examine the performance of MA-dependent individuals on a task of spatial attention. METHOD: 51 MA-dependent subjects and 22 age-matched non-substance abusing control subjects were tested on a Spatial Stroop attention test. MR Spectroscopy (MRS) imaging data were analyzed from 32 MA abusers and 13 controls. RESULTS: No group differences in response time or accuracy emerged on the behavioral task with both groups exhibiting equivalent slowing when the word meaning and the spatial location of the word were in conflict. MRS imaging data from the MA abusers revealed a strong inverse correlation between NAA/Cr ratios in the Primary Visual Cortex (PVC) and spatial interference (p=0.0001). Moderate inverse correlations were also seen in the Anterior Cingulate Cortex (ACC) (p=0.02). No significant correlations were observed in the controls, perhaps due to the small sample of imaging data available (n=13). DISCUSSION: The strong correlation between spatial conflict suppression and NAA/Cr levels within the PVC in the MA-dependent individuals suggests that preserved neuronal integrity within the PVC of stimulant abusers may modulate cognitive mechanisms that process implicit spatial information.

Unexplained excess of electronlike events from a 1-GeV neutrino beam.

The MiniBooNE Collaboration observes unexplained electronlike events in the reconstructed neutrino energy range from 200 to 475 MeV. With 6.46x10;{20} protons on target, 544 electronlike events are observed in this energy range, compared to an expectation of 415.2+/-43.4 events, corresponding to an excess of 128.8+/-20.4+/-38.3 events. The shape of the excess in several kinematic variables is consistent with being due to either nu_{e} and nu[over ]_{e} charged-current scattering or nu_{mu} neutral-current scattering with a photon in the final state. No significant excess of events is observed in the reconstructed neutrino energy range from 475 to 1250 MeV, where 408 events are observed compared to an expectation of 385.9+/-35.7 events.

Search for electron antineutrino appearance at the deltam(2) approximately 1 eV(2) Scale.

The MiniBooNE Collaboration reports initial results from a search for nu(mu)-->nu(e) oscillations. A signal-blind analysis was performed using a data sample corresponding to 3.39x10(20) protons on target. The data are consistent with background prediction across the full range of neutrino energy reconstructed assuming quasielastic scattering, 200

Search for muon neutrino and antineutrino disappearance in MiniBooNE.

The MiniBooNE Collaboration reports a search for nu_{micro} and nu[over]_{micro} disappearance in the Deltam;{2} region of 0.5-40 eV;{2}. These measurements are important for constraining models with extra types of neutrinos, extra dimensions, and CPT violation. Fits to the shape of the nu_{micro} and nu[over]_{micro} energy spectra reveal no evidence for disappearance at the 90% confidence level (C.L.) in either mode. The test of nu[over]_{micro} disappearance probes a region below Deltam;{2} = 40 eV;{2} never explored before.

Measurement of the ratio of the numu charged-current single-pion production to quasielastic scattering with a 0.8 GeV neutrino beam on mineral oil.

Using high statistics samples of charged-current numu interactions, the MiniBooNE [corrected] Collaboration reports a measurement of the single-charged-pion production to quasielastic cross section ratio on mineral oil (CH2), both with and without corrections for hadron reinteractions in the target nucleus. The result is provided as a function of neutrino energy in the range 0.4 GeV

Measurement of muon neutrino quasielastic scattering on carbon.

The observation of neutrino oscillations is clear evidence for physics beyond the standard model. To make precise measurements of this phenomenon, neutrino oscillation experiments, including MiniBooNE, require an accurate description of neutrino charged current quasielastic (CCQE) cross sections to predict signal samples. Using a high-statistics sample of nu_(mu) CCQE events, MiniBooNE finds that a simple Fermi gas model, with appropriate adjustments, accurately characterizes the CCQE events observed in a carbon-based detector. The extracted parameters include an effective axial mass, M_(A)(eff)=1.23+/-0.20 GeV, that describes the four-momentum dependence of the axial-vector form factor of the nucleon, and a Pauli-suppression parameter, kappa=1.019+/-0.011. Such a modified Fermi gas model may also be used by future accelerator-based experiments measuring neutrino oscillations on nuclear targets.

Search for electron neutrino appearance at the Delta m2 approximately 1 eV2 scale.

The MiniBooNE Collaboration reports first results of a search for nu e appearance in a nu mu beam. With two largely independent analyses, we observe no significant excess of events above the background for reconstructed neutrino energies above 475 MeV. The data are consistent with no oscillations within a two-neutrino appearance-only oscillation model.

The solubilization of model Alzheimer tangles: reversing the beta-sheet conformation induced by aluminum with silicates.

Neurofibrillary tangles are one of two lesions found in the brain of Alzheimer disease victims. With synthetic peptide fragments of human neurofilament NF-M17 (Glu-Glu-Lys-Gly-Lys-Ser-Pro- Val-Pro-Lys-Ser-Pro-Val-Glu-Glu-Lys-Gly, phosphorylated and unphosphorylated), CD studies were done to examine the effect of sodium orthosilicate on the conformational state produced by Al3+ on fragments of neuronal proteins. Previous studies had shown a conformational transition from alpha-helix and random to beta-pleated sheet upon addition of Al3+ to both phosphorylated and unphosphorylated peptides. If sufficient quantities of Al3+ are added, the peptide precipitates from solution. The ability to reverse or slow the progression of aggregation was examined. Al3+ binding was reversed with 1-2 molar equivalents of sodium orthosilicate (with respect to Al3+), altering the conformation from beta-sheet to random coil and resulting in a CD spectrum similar to that of the initial peptide. The tight binding of the SiO4(4-) with the Al3+ provides the mechanism for this transition. These results provide additional information toward understanding the role of aluminum in the Alzheimer diseased brain and suggest the investigation of the possible use of silicates as a therapeutic agent.

Characterization of an independent structural unit in apocytochrome b5.

Apocytochrome b5 is a partially folded protein which contains a stable structural unit under native conditions [Moore, C.D., Al-Misky, O.N., & Lecomte, J.T.J. (1990) Biochemistry 30, 8357-8365]. In this work, the fold of the unit was examined by using 1H and 15N-edited two-dimensional NMR spectroscopy. It was found that it contains four of the five beta-strands and two of the six alpha-helices present in the holoprotein. The remainder of the structure appears to be mostly unstructured and fluctuating among several conformations. The structural unit is stabilized by a hydrophobic core formed by residues from each of the folded elements of secondary structure. Nuclear Overhauser effects and chemical shift values demonstrated that the unit is structurally similar in the apo- and holoproteins. However, the backbone amide hydrogen exchange was found to be much accelerated in the apoprotein. The paramagnetic relaxation agent HyTEMPO was used to probe the packing of the structure. HyTEMPO has unrestricted access to the empty heme binding site whereas it is unable to penetrate the stabilizing core. It was concluded that addition of the heme is necessary for the last strand to dock properly to the rest of the sheet. The kinetics of refolding of the apoprotein were monitored by stopped-flow fluorescence spectroscopy. Extensive protection of the sole tryptophan residue by docking of the two polypeptide termini occurs in less than 60 ms. It was proposed that apocytochrome b5, with its two-region behavior, might serve as a model for the design of proteins which bind a prosthetic group.

Low doses of ethanol have Ca2+ ionophore-like effects on apical membrane potential of in vitro Necturus antrum.

The effects of low doses of luminal ethanol on the amiloride-sensitive apical membrane potential of Necturus antral mucosa were studied using conventional microelectrode techniques. Luminal ethanol (0.250-4.0% vol/vol) caused a dose-dependent hyperpolarization of the apical membrane potential (Vmc), an increase in transepithelial resistance (Rt) and resistance ratio (Ra/Rb), and a decrease in transepithelial potential (Vms). Luminal amiloride (100 microM) to 4% ethanol-treated antra did not cause any additional hyperpolarization of Vmc. Compared with luminal 2% ethanol-Ringer, an equivalent osmotic mannitol solution depolarized Vmc and basolateral potential (Vcs), decreased Rt and Ra/Rb, and increased Vms. A single dose of 0.50% ethanol attenuated the effects of a second 2% ethanol exposure on Vmc. No change in periodic acid-Schiff (PAS)-positive mucous granule content could be found between control and 2% ethanol-treated antra. The Ca2+ ionophores A23187 or ionomycin (0.25-5.0 microM) dose dependently hyperpolarized the Vmc and Vcs, increased Rt and Ra/Rb, and decreased Vms. Luminal Ca(2+)-free Ringer had no effect on luminal 2.00% ethanol-induced changes in membrane potentials or resistances. Pretreatment with BAPTA blocked by approximately 70 and 55% the Vmc hyperpolarization of 2 and 4% ethanol, respectively. Pretreatment with ruthenium red (10-50 microM) also dose dependently reduced the 2% ethanol-induced changes in Vmc. The data indicate that 1) low doses of luminal ethanol and Ca2+ ionophores have similar effects on Necturus gastric antral membrane potentials and resistances, 2) ethanol-induced hyperpolarizations of the Vmc are partially mediated through an alteration in intracellular Ca2+, and 3) low doses of luminal ethanol do not cause the release of antral epithelial mucous granules at the time when significant changes are occurring in the Vmc.