Electron-beam energy reconstruction for neutrino oscillation measurements.

Neutrinos exist in one of three types or 'flavours'-electron, muon and tau neutrinos-and oscillate from one flavour to another when propagating through space. This phenomena is one of the few that cannot be described using the standard model of particle physics (reviewed in ref. 1), and so its experimental study can provide new insight into the nature of our Universe (reviewed in ref. 2). Neutrinos oscillate as a function of their propagation distance (L) divided by their energy (E). Therefore, experiments extract oscillation parameters by measuring their energy distribution at different locations. As accelerator-based oscillation experiments cannot directly measure E, the interpretation of these experiments relies heavily on phenomenological models of neutrino-nucleus interactions to infer E. Here we exploit the similarity of electron-nucleus and neutrino-nucleus interactions, and use electron scattering data with known beam energies to test energy reconstruction methods and interaction models. We find that even in simple interactions where no pions are detected, only a small fraction of events reconstruct to the correct incident energy. More importantly, widely used interaction models reproduce the reconstructed energy distribution only qualitatively and the quality of the reproduction varies strongly with beam energy. This shows both the need and the pathway to improve current models to meet the requirements of next-generation, high-precision experiments such as Hyper-Kamiokande (Japan)3 and DUNE (USA)4.

The epidemiological status of African swine fever in domestic swine herds in the Tavush Province region, Armenia.

KEEN The factors associated with the spread and persistence of African swine fever (ASF) in the Caucasus region remain to be fully identified. It is assumed that large naive populations of domestic free-ranging and wild pigs are critical to disease transmission and maintenance. Nonetheless, 11 years since its epidemic introduction into the region in 2007, ASF virus (ASFV) is still circulating, suggesting that an endemic cycle has been established based on contact between free-ranging domestic pigs and wild pigs, and that native Ornithodoros ticks probably serve as reservoirs for the virus. Therefore, research is required to gather information on the epidemiological status of ASF in the Caucasus region, focusing particularly on understanding modes of ASFV spread and persistence in this new virus environment. The authors established an ASFV survey targeting domestic pigs in the Tavush province of northern Armenia, an area of the country considered to be at high risk of disease incursion/occurrence. All tested samples collected for this survey were negative for ASF. The probability of observing no reactors by antibody enzyme-linked immunosorbent assay in a sample of this size (n = 1,506) from a population with an estimated disease prevalence of 1% is very low (< 0.0001). Therefore, it is possible but very unlikely for ASFV to be present among domestic pigs in the Tavush province region.

Les facteurs associés à la propagation de la peste porcine africaine (PPA) dans le Caucase et à sa persistance restent en grande partie à élucider. On suppose que la présence de populations naïves de porcs domestiques en liberté et de porcs sauvages joue un rôle déterminant dans la transmission et le maintien de la maladie. Néanmoins, 11 ans après son introduction épidémique dans la région en 2007, le virus de la peste porcine africaine (VPPA) est toujours présent, ce qui laisse penser qu'un cycle s'est installé à la faveur des contacts entre les porcs domestiques en liberté et les porcs sauvages, les tiques autochtones Ornithodoros faisant probablement office de réservoir viral. Des études sont donc nécessaires pour recueillir des informations sur le statut épidémiologique de la PPA dans le Caucase et plus particulièrement pour comprendre les modalités de la propagation et de la persistance du VPPA dans ce nouvel environnement. Les auteurs rapportent les résultats d'une enquête épidémiologique sur le VPPA conduite chez les porcs domestiques de la province du Tavush, au nord de l'Arménie, zone considérée comme présentant un risque élevé d'incursion et d'émergence de la maladie. Les échantillons prélevés à cette fin ont tous donné des résultats négatifs au test de détection de la PPA. La probabilité qu'un échantillon de cette taille (n = 1 506) ne donne aucune réaction positive à l'épreuve ELISA de détection d'anticorps dans une population pour laquelle la prévalence de la maladie est estimée à 1 % est extrêmement faible (< 0,0001). On peut en conclure que la présence du VPPA parmi les porcs domestiques de la région du Tavush est possible, mais très improbable.

Aún no están perfectamente identificados los factores que intervienen en la propagación y persistencia de la peste porcina africana (PPA) en la región del Cáucaso. Se presupone que la existencia de grandes poblaciones de cerdos salvajes y cerdos domésticos en libertad que no han estado expuestas previamente al patógeno es un factor crucial en la transmisión y el mantenimiento de la enfermedad. Sin embargo, 11 años después de su penetración epidémica en la región, en 2007, el virus de la PPA aún sigue en circulación, hecho que parece apuntar al establecimiento de un ciclo endémico mediado por el contacto entre cerdos domésticos en libertad y cerdos salvajes y también a la probable función de la garrapata autóctona Ornithodoros como reservorio del virus. Por consiguiente, es necesario investigar para reunir información sobre la situación epidemiológica de la PPA en la región del Cáucaso, procurando especialmente aprehender las modalidades de propagación y persistencia del virus en este nuevo entorno. Los autores estudiaron la presencia del virus de la PPA específicamente en cerdos domésticos de la provincia de Tavush, al norte de Armenia, una zona del país considerada muy expuesta al riesgo de incursión o manifestación de la enfermedad. Todas las muestras obtenidas y analizadas para el estudio dieron resultado negativo a la PPA. La probabilidad de no detectar con ELISA ningún ejemplar con anticuerpos en una muestra de tal tamaño (n = 1 506), tomada de una población con una prevalencia de la enfermedad que según los cálculos es del 1%, resulta ínfima (<0,0001). Es por lo tanto posible, pero harto improbable, que el virus de la PPA esté presente en los cerdos domésticos de la zona de la provincia de Tavush.

Oxytocin induces a conditioned social preference in female mice.

Friendships and other rewarding affilliative bonds are associated with the actions of the nonapeptide hormone oxytocin (OT) in humans and many social mammals. We investigated whether OT itself is rewarding, and if that reward is dependent upon the presence of conspecifics. We evaluated the reinforcing effects of OT infusion in female mice on social (conditioned social preference; CSP) and nonsocial tests (conditioned place preference; CPP). Ovariectomised females received oestradiol implants and i.c.v. cannulas. During a pre-test, they were introduced to a three-chamber apparatus for 10 min. Social and place apparatus were identical, except that each end-chamber contained a novel stimulus female for CSP, whereas they were distinguished by visual and tactile cues for CPP. For CSP, test females received OT (0, 100, 200 or 100 ng) and were paired for 30 min with one stimulus female. On alternating days, they received saline vehicle and were paired with the opposite female, for a total of four pairings each. The final conditioned preference test was identical to the pre-test. OT induced CSP. Test mice that received 100 ng of OT increased their preference score from -67.4 ± 22.1 s in pre-test to +55.7 ± 35.1 s during the conditioned preference test (P < 0.05). It was observed that 200 ng OT induced an increase in preference score from -162.7 ± 47.3 to +74.3 ± 23.7 s (P < 0.001). There was no effect of 0 or 1000 ng of OT on CSP. An additional group of mice was tested for CPP at 200 ng of OT. Testing and pairings were identical to CSP. OT induced a small but significant CPP. Mice increased their preference score from -222.4 ± 38.0 to -126.0 ± 58.7 s (P < 0.05). OT had no effect on anxiety or odour recognition, as assessed by elevated plus maze and olfactory habituation/dishabituation tests, respectively. In conclusion, OT, similar to other motivating stimuli (drugs, food), not only is rewarding when tested under solitary conditions, but also is reinforcing in a social setting.