Measurement of the axial vector form factor from antineutrino-proton scattering.

Scattering of high energy particles from nucleons probes their structure, as was done in the experiments that established the non-zero size of the proton using electron beams1. The use of charged leptons as scattering probes enables measuring the distribution of electric charges, which is encoded in the vector form factors of the nucleon2. Scattering weakly interacting neutrinos gives the opportunity to measure both vector and axial vector form factors of the nucleon, providing an additional, complementary probe of their structure. The nucleon transition axial form factor, FA, can be measured from neutrino scattering from free nucleons, νµn → µ-p and [Formula: see text], as a function of the negative four-momentum transfer squared (Q2). Up to now, FA(Q2) has been extracted from the bound nucleons in neutrino-deuterium scattering3-9, which requires uncertain nuclear corrections10. Here we report the first high-statistics measurement, to our knowledge, of the [Formula: see text] cross-section from the hydrogen atom, using the plastic scintillator target of the MINERvA11 experiment, extracting FA from free proton targets and measuring the nucleon axial charge radius, rA, to be 0.73 ± 0.17 fm. The antineutrino-hydrogen scattering presented here can access the axial form factor without the need for nuclear theory corrections, and enables direct comparisons with the increasingly precise lattice quantum chromodynamics computations12-15. Finally, the tools developed for this analysis and the result presented are substantial advancements in our capabilities to understand the nucleon structure in the weak sector, and also help the current and future neutrino oscillation experiments16-20 to better constrain neutrino interaction models.

Simultaneous Measurement of Muon Neutrino ν_{µ} Charged-Current Single π

Neutrino-induced charged-current single π^{+} production in the Δ(1232) resonance region is of considerable interest to accelerator-based neutrino oscillation experiments. In this Letter, high statistic differential cross sections are reported for the semiexclusive reaction ν_{µ}A→µ^{-}π^{+}+ nucleon(s) on scintillator, carbon, water, iron, and lead targets recorded by MINERvA using a wideband ν_{µ} beam with ⟨E_{ν}⟩≈6 GeV. Suppression of the cross section at low Q^{2} and enhancement of low T_{π} are observed in both light and heavy nuclear targets compared with phenomenological models used in current neutrino interaction generators. The cross sections per nucleon for iron and lead compared with CH across the kinematic variables probed are 0.8 and 0.5 respectively, a scaling which is also not predicted by current generators.

Simultaneous Measurement of ν_{µ} Quasielasticlike Cross Sections on CH, C, H_{2}O, Fe, and Pb as a Function of Muon Kinematics at MINERvA.

This Letter presents the first simultaneous measurement of the quasielasticlike neutrino-nucleus cross sections on C, water, Fe, Pb, and scintillator (hydrocarbon or CH) as a function of longitudinal and transverse muon momentum. The ratio of cross sections per nucleon between Pb and CH is always above unity and has a characteristic shape as a function of transverse muon momentum that evolves slowly as a function of longitudinal muon momentum. The ratio is constant versus longitudinal momentum within uncertainties above a longitudinal momentum of 4.5 GeV/c. The cross section ratios to CH for C, water, and Fe remain roughly constant with increasing longitudinal momentum, and the ratios between water or C to CH do not have any significant deviation from unity. Both the overall cross section level and the shape for Pb and Fe as a function of transverse muon momentum are not reproduced by current neutrino event generators. These measurements provide a direct test of nuclear effects in quasielasticlike interactions, which are major contributors to long-baseline neutrino oscillation data samples.

Simultaneous Measurement of Proton and Lepton Kinematics in Quasielasticlike ν_{µ}-Hydrocarbon Interactions from 2 to 20 GeV.

Neutrino charged-current quasielastic-like scattering, a reaction category extensively used in neutrino oscillation measurements, probes nuclear effects that govern neutrino-nucleus interactions. This Letter reports the first measurement of the triple-differential cross section for ν_{µ} quasielastic-like reactions using the hydrocarbon medium of the MINERvA detector exposed to a wideband beam spanning 2≤E_{ν}≤20 GeV. The measurement maps the correlations among transverse and longitudinal muon momenta and summed proton kinetic energies, and compares them to predictions from a state-of-art simulation. Discrepancies are observed that likely reflect shortfalls with modeling of pion and nucleon intranuclear scattering and/or spectator nucleon ejection from struck nuclei. The separate determination of leptonic and hadronic variables can inform experimental approaches to neutrino-energy estimation.

High-Statistics Measurement of Neutrino Quasielasticlike Scattering at 6 GeV on a Hydrocarbon Target.

We measure neutrino charged-current quasielasticlike scattering on hydrocarbon at high statistics using the wideband Neutrinos at the Main Injector beam with neutrino energy peaked at 6 GeV. The double-differential cross section is reported in terms of muon longitudinal (p_{∥}) and transverse (p_{⊥}) momentum. Cross section contours versus lepton momentum components are approximately described by a conventional generator-based simulation, however, discrepancies are observed for transverse momenta above 0.5 GeV/c for longitudinal momentum ranges 3-5 and 9-20 GeV/c. The single differential cross section versus momentum transfer squared (dσ/dQ_{QE}^{2}) is measured over a four-decade range of Q^{2} that extends to 10 GeV^{2}. The cross section turnover and falloff in the Q^{2} range 0.3-10 GeV^{2} is not fully reproduced by generator predictions that rely on dipole form factors. Our measurement probes the axial-vector content of the hadronic current and complements the electromagnetic form factor data obtained using electron-nucleon elastic scattering. These results help oscillation experiments because they probe the importance of various correlations and final-state interaction effects within the nucleus, which have different effects on the visible energy in detectors.

Publisher's Note: Identification of Nuclear Effects in Neutrino-Carbon Interactions at Low Three-Momentum Transfer [Phys. Rev. Lett. 116, 071802 (2016)].

This corrects the article DOI: 10.1103/PhysRevLett.116.071802.

Measurement of Final-State Correlations in Neutrino Muon-Proton Mesonless Production on Hydrocarbon at ⟨E_{ν}⟩=3 GeV.

Final-state kinematic imbalances are measured in mesonless production of ν_{µ}+A→µ^{-}+p+X in the MINERvA tracker. Initial- and final-state nuclear effects are probed using the direction of the µ^{-}-p transverse momentum imbalance and the initial-state momentum of the struck neutron. Differential cross sections are compared to predictions based on current approaches to medium modeling. These models underpredict the cross section at intermediate intranuclear momentum transfers that generally exceed the Fermi momenta. As neutrino interaction models need to correctly incorporate the effect of the nucleus in order to predict neutrino energy resolution in oscillation experiments, this result points to a region of phase space where additional cross section strength is needed in current models, and demonstrates a new technique that would be suitable for use in fine-grained liquid argon detectors where the effect of the nucleus may be even larger.

OnabotulinumtoxinA in chronic migraine: predictors of response. A prospective multicentre descriptive study.

BACKGROUND AND PURPOSE: OnabotulinumtoxinA is a treatment specifically approved for the prophylaxis of chronic migraine in adults. The aim of this study was to assess the effectiveness of OnabotulinumtoxinA in chronic migraine after 1 year of treatment in a real-life setting and to identify clinical predictors of outcome. METHODS: We designed a prospective multicentre study performed in 13 hospitals in Spain. Patients underwent a complete medical history and examination. They were treated with OnabotulinumtoxinA every 12 weeks for 1 year. Data about outcome, adverse events, abortive medication use, emergency room use and disability were collected at 3 and 12 months. RESULTS: A total of 725 subjects completed the study. At 12 months, 79.3% showed >50% reduction in number of headaches per month and 94.9% reported no adverse events. Unilaterality of pain, fewer days of disability per month and milder headache at baseline were correlated with good outcome. Duration of disease <12 months increased the chances of response to treatment with OnabotulinumtoxinA (odds ratio, 1.470; 95% confidence interval, 1.123-2.174; P = 0.045). CONCLUSIONS: This study confirmed the effectiveness of treatment with OnabotulinumtoxinA after 1 year of treatment. The chances of a good outcome may be increased by starting treatment in the first 12 months after chronic migraine diagnosis.

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.

Measurement of Electron Neutrino Quasielastic and Quasielasticlike Scattering on Hydrocarbon at ⟨E_{ν}⟩=3.6 GeV.

The first direct measurement of electron neutrino quasielastic and quasielasticlike scattering on hydrocarbon in the few-GeV region of incident neutrino energy has been carried out using the MINERvA detector in the NuMI beam at Fermilab. The flux-integrated differential cross sections in the electron production angle, electron energy, and Q^{2} are presented. The ratio of the quasielastic, flux-integrated differential cross section in Q^{2} for ν_{e} with that of similarly selected ν_{µ}-induced events from the same exposure is used to probe assumptions that underpin conventional treatments of charged-current ν_{e} interactions used by long-baseline neutrino oscillation experiments. The data are found to be consistent with lepton universality and are well described by the predictions of the neutrino event generator GENIE.

Identification of Nuclear Effects in Neutrino-Carbon Interactions at Low Three-Momentum Transfer.

Two different nuclear-medium effects are isolated using a low three-momentum transfer subsample of neutrino-carbon scattering data from the MINERvA neutrino experiment. The observed hadronic energy in charged-current ν_{µ} interactions is combined with muon kinematics to permit separation of the quasielastic and Δ(1232) resonance processes. First, we observe a small cross section at very low energy transfer that matches the expected screening effect of long-range nucleon correlations. Second, additions to the event rate in the kinematic region between the quasielastic and Δ resonance processes are needed to describe the data. The data in this kinematic region also have an enhanced population of multiproton final states. Contributions predicted for scattering from a nucleon pair have both properties; the model tested in this analysis is a significant improvement but does not fully describe the data. We present the results as a double-differential cross section to enable further investigation of nuclear models. Improved description of the effects of the nuclear environment are required by current and future neutrino oscillation experiments.

ASIC2 is present in human mechanosensory neurons of the dorsal root ganglia and in mechanoreceptors of the glabrous skin.

Mechanosensory neurons lead to the central nervous system touch, vibration and pressure sensation. They project to the periphery and form different kinds of mechanoreceptors. The manner in which they sense mechanical signals is still not fully understood, but electrophysiological experiments have suggested that this may occur through the activation of ion channels that gate in response to mechanical stimuli. The acid-sensing ion channels (ASICs), especially ASIC2, may function as mechanosensors or are required for mechanosensation, and they are expressed in both mechanosensory neurons and mechanoreceptors. Here, we have used double immunohistochemistry for ASIC2 together with neuronal and glial markers associated with laser confocal microscopy and image analysis, to investigate the distribution of ASIC2 in human lumbar dorsal root ganglia, as well as in mechanoreceptors of the hand and foot glabrous skin. In lumbar dorsal root ganglia, ASIC2 immunoreactive neurons were almost all intermediate or large sized (mean diameter ≥20-70 µm), and no ASIC2 was detected in the satellite glial. ASIC2-positive axons were observed in Merkel cell-neurite complexes, Meissner and Pacinian corpuscles, all of them regarded as low-threshold mechanoreceptors. Moreover, a variable percent of Meissner (8 %) and Pacinian corpuscles (27 %) also displayed ASIC2 immunoreactivity in the Schwann-related cells. These results demonstrate the distribution of ASIC2 in the human cutaneous mechanosensory system and suggest the involvement of ASIC2 in mechanosensation.

Measurement of ratios of νµ charged-current cross sections on C, Fe, and Pb to CH at neutrino energies 2-20 GeV.

We present measurements of ν(µ) charged-current cross section ratios on carbon, iron, and lead relative to a scintillator (CH) using the fine-grained MINERvA detector exposed to the NuMI neutrino beam at Fermilab. The measurements utilize events of energies 2

Measurement of muon antineutrino quasielastic scattering on a hydrocarbon target at Eν ~ 3.5 GeV.

We have isolated ν(µ) charged-current quasielastic (QE) interactions occurring in the segmented scintillator tracking region of the MINERvA detector running in the NuMI neutrino beam at Fermilab. We measure the flux-averaged differential cross section, dσ/dQ², and compare to several theoretical models of QE scattering. Good agreement is obtained with a model where the nucleon axial mass, M(A), is set to 0.99 GeV/c² but the nucleon vector form factors are modified to account for the observed enhancement, relative to the free nucleon case, of the cross section for the exchange of transversely polarized photons in electron-nucleus scattering. Our data at higher Q² favor this interpretation over an alternative in which the axial mass is increased.

Measurement of muon neutrino quasielastic scattering on a hydrocarbon target at Eν ~ 3.5 GeV.

We report a study of ν(µ) charged-current quasielastic events in the segmented scintillator inner tracker of the MINERvA experiment running in the NuMI neutrino beam at Fermilab. The events were selected by requiring a µ- and low calorimetric recoil energy separated from the interaction vertex. We measure the flux-averaged differential cross section, dσ/dQ², and study the low energy particle content of the final state. Deviations are found between the measured dσ/dQ² and the expectations of a model of independent nucleons in a relativistic Fermi gas. We also observe an excess of energy near the vertex consistent with multiple protons in the final state.

[Failure of extension of epidural analgesia to anesthesia for emergency cesarean section]. / Fallo en la conversión de la analgesia epidural en anestesia epidural quirúrgica cuando se indica cesárea urgente.

Epidural analgesia provides effective control of labor pain and allows emergency cesarean section to be performed without recourse to general anesthesia. This technique is subject to failure, however. We sought to determine the incidence of failure of extension of epidural analgesia for labor to epidural anesthesia for emergency cesarean section. We also analyzed possible risk factors for failure. A 2-month observational study was carried out in a tertiary-care university hospital in patients who had an epidural catheter inserted for labor analgesia and who later underwent emergency cesarean section. Epidural catheter failure was defined if additional analgesia was required during surgery or if general anesthesia was required. Data were gathered on possible risk factors, such as obesity, difficult epidural puncture, leakage of blood on insertion, history of cesarean delivery, need for rescue analgesia, and level of satisfaction with analgesia during dilation. In total, 134 emergency cesareans were performed in women carrying an epidural catheter. The catheter failed to administer the anesthetic in 18 patients (13.4%). General anesthesia was required in 9 cases (6.7%). Difficult insertion (more than 2 attempts) was associated with a higher failure rate (P=.064). The relative risk of epidural catheter failure was 2.86-fold higher when rescue analgesia was needed during delivery than in cases when no supplement was required (P=.021). Receiving adequate analgesia during labor seems to be a protective factor (80%) against anesthetic catheter failure during cesarean section (P=.01). We conclude that high demand for rescue analgesia and signs of inadequate analgesia during labor should warn of epidural catheter failure if extension to anesthesia becomes necessary for a cesarean delivery.

Evaluation of in vivo and in vitro recovery rate of anatoxin-a through the microdialysis probe.

In vivo microdialysis is a versatile sampling technique commonly employed to observe changes in neurotransmitters levels that occur in response to different treatments, being these treatments administered through a microdialysis probe implanted into a specific brain region in living animals. In previous works we have used this technique to study the effects of the drug anatoxin-a, a nicotinic acetylcholine receptor agonist, on dopamine release in striatum. The aim of the present study was to assess the recovery of anatoxin-a through the microdialysis probe. This information allows knowing the exact amount of the drug crossing the microdialysis membrane, acting on extracellular tissue. High Performance Liquid Chromatography (HPLC) with Fluorescence Detection (FLD) has been used for the analysis of anatoxin-a. We observed that the recovery of anatoxin-a was about 0.5%. Under our experimental conditions, the results suggest that anatoxin-a can be used as an important tool in the study of neuronal nicotinic receptors by in vivo microdialysis technique and also show a reliable estimation of the anatoxin-a recovery through the microdialysis probe under both in vivo and in vitro conditions.

A hydrodynamic model of labyrinth to study the stimulation of perilymph compartments by audioprostheses.

CONCLUSIONS: The hydrodynamic model of the labyrinth spaces (LHM) is a useful tool for research on implantable audioprostheses, in particular to develop suitable actuators using MEMS technology (micro-electromechanic machine system). It has other potential applications for auditory research. OBJECTIVES: The energy reaching the labyrinth fluids is crucial information for developing prostheses to substitute the tympanic-ossicular system because adequate stimulation of the cochlear partition is essential. However, in vivo measurements in human ears are not currently available. Therefore a model of the normal labyrinth resembling its hydrodynamic properties becomes a valuable tool. It could allow comparison of different processing systems, algorithms and transducers, to develop new audioprostheses and improve their effectiveness and efficiency. MATERIALS AND METHODS: This work presents one LHM that emulates the conduction of the stimuli from the stapes footplate through the labyrinthine fluids, including its dimensions and physical properties, and some examples of measurements of perilymph stimulation by different audioprostheses and algorithms. RESULTS. As shown in the reported examples, this LHM provided effective measurement of acoustic stimulation across the whole human auditory frequency and intensity spectrum. Air-delivered and direct stimulation methods are possible. This provided convenient information for the actuator development and allowed comparison between different prototypes, stimulation patterns and algorithms.

Highly active nano-sized iridium catalysts: synthesis and operando spectroscopy in a proton exchange membrane electrolyzer.

A stable and cost effective oxygen evolution reaction (OER) catalyst is crucial for the large-scale market penetration of proton exchange membrane (PEM) water electrolyzers. We show that the synthesis of iridium nanoparticles in either low purity ethanol or water, or in the absence of a surfactant, is detrimental to the electrocatalytic properties of the materials. Adding NaBH4 in excess improves the purity of the catalyst enhancing the OER activity up to 100 A gIr-1 at 1.51 V vs. RHE, the highest value reported so far for high purity Ir nanoparticles. The measured OER activity correlates with the capacitive current rather than with the charge corresponding to the IrIII/IrIV oxidation peak. Operando near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) on membrane electrode assemblies (MEAs) with the synthesized catalysts reveals a metallic core surrounded by a thin layer of IrIII/IV oxides/hydroxides. Oxidation of IrIII leaves behind a porous ultrathin layer of IrIV oxides/hydroxides, which dominate the surface during the OER, while IrV was not detected.

Low-Cost and Durable Bipolar Plates for Proton Exchange Membrane Electrolyzers.

Cost reduction and high efficiency are the mayor challenges for sustainable H2 production via proton exchange membrane (PEM) electrolysis. Titanium-based components such as bipolar plates (BPP) have the largest contribution to the capital cost. This work proposes the use of stainless steel BPPs coated with Nb and Ti by magnetron sputtering physical vapor deposition (PVD) and vacuum plasma spraying (VPS), respectively. The physical properties of the coatings are thoroughly characterized by scanning electron, atomic force microscopies (SEM, AFM); and X-ray diffraction, photoelectron spectroscopies (XRD, XPS). The Ti coating (50 µm) protects the stainless steel substrate against corrosion, while a 50-fold thinner layer of Nb decreases the contact resistance by almost one order of magnitude. The Nb/Ti-coated stainless steel bipolar BPPs endure the harsh environment of the anode for more than 1000 h of operation under nominal conditions, showing a potential use in PEM electrolyzers for large-scale H2 production from renewables.