Sun-as-a-Star Observation of Flares in Lyman {\alpha} by the PROBA2/LYRA radiometer

There are very few reports of flare signatures in the solar irradiance at H i Lyman {\alpha} at 121.5 nm, i.e. the strongest line of the solar spectrum. The LYRA radiometer onboard PROBA2 has observed several flares for which unambiguous signatures have been found in its Lyman-{\alpha} channel. Here we present a brief overview of these observations followed by a detailed study of one of them, the M2 flare that occurred on 8 February 2010. For this flare, the flux in the LYRA Lyman-{\alpha} channel increased by 0.6%, which represents about twice the energy radiated in the GOES soft X-ray channel and is comparable with the energy radiated in the He ii line at 30.4 nm. The Lyman-{\alpha} emission represents only a minor part of the total radiated energy of this flare, for which a white-light continuum was detected. Additionally, we found that the Lyman-{\alpha} flare profile follows the gradual phase but peaks before other wavelengths. This M2 flare was very localized and has a very brief impulsive phase, but more statistics are needed to determine if these factors influence the presence of a Lyman-{\alpha} flare signal strong enough to appear in the solar irradiance.Comment: in press for Solar Physic

Acute pancreatitis in dogs and cats: medical imaging, biopsy, treatment and prognosis

Diagnosing acute pancreatitis in dogs and cats is difficult. Abdominal ultrasonography provides specific information about the size, shape and homogeneity of the pancreas, but is very dependent on the experience of the operator and the quality of the echography machine. Abdominal radiography is less useful, while computed tomography is less practicable in veterinary patients because of the anesthesia risks, the need for experienced operators, and the high cost. Furthermore, computed tomography has low diagnostic value in cats. Biopsy of pancreatic tissue remains the gold standard. Treatment consists of fluid therapy and nutritional support, combined with pain medication, anti-emetics and antibiotics. The prognosis in dogs and cats is variable and largely depends on the clinical condition of the patient at admission. It is usually guarded, especially in cats

The LYRA Instrument Onboard PROBA2: Description and In-Flight Performance

The Large Yield Radiometer (LYRA) is an XUV-EUV-MUV (soft X-ray to mid-ultraviolet) solar radiometer onboard the European Space Agency PROBA2 mission that was launched in November 2009. LYRA acquires solar irradiance measurements at a high cadence (nominally 20 Hz) in four broad spectral channels, from soft X-ray to MUV, that have been chosen for their relevance to solar physics, space weather and aeronomy. In this article, we briefly review the design of the instrument, give an overview of the data products distributed through the instrument website, and describe the way that data are calibrated. We also briefly present a summary of the main fields of research currently under investigation by the LYRA consortium

Création de haies-vives par semis directs : problématique, premières expérimentations en Nord Côte d'Ivoire

La délimitation du parcellaire ·par des haie-vive est un domaine en pleine extension en milieu paysan sénoufo. Depuis 1988, la station de Korhogo du Département Foresterie de l'Institut des Forêts (IDEFOR-DFO) de Côte d'Ivoire mène, avec l'appui du Centre Technique Forestier Tropical (CTFT) des recherches sur la création de haies-vives à but défensif. Un des programmes de recherche concerne la mise au point des techniques de création de haies par semis direct, Dans ce programme les thèmes abordés concernent la levée de dormance des graines et leur conservation après traitement et l'élimination de la concurrence herbacée qui est la cause majeure d'échec de création de hales par semis. Les premiers essais, menés avec des graines gonflées par trempage à l'eau montrent que la germination en milieu naturel est, pour de nombreuses espèces, bien inférieure à celle des tests en laboratoire: Il est donc important de bien maîtriser le prétraitement des graines. Ceci a eté fait pour Bauhinia rufescens et Dichrostachys cinerea. Ziziphus mauritiana décortiqué ne nécessite pas de prétraitement. Les essais ont montré que si la croissance en première année des semis était inférieure à celle des plants Issus de pépinière, le retard initial diminue en seconde année, voire disparaît pour certaines espèces ou provenances. Les premiers essais d'entretien de haies par herbicides ont permis de sélectionner un herbicide de prélevée à épandre juste après le semis de la haie. Pour les entretiens en cours de saison des pluies 2 herbicides ont donné des résultats satisfaisants. La vulgarisation du semis direct pour la création de haies peut être entreprise en pays sénoufo si, de quelque manière que ce soit, l'accès aux graines est aisé et si celles-ci sont bon marché

Anderson localization of solitons

At low temperature, a quasi-one-dimensional ensemble of atoms with attractive interaction forms a bright soliton. When exposed to a weak and smooth external potential, the shape of the soliton is hardly modified, but its center-of-mass motion is affected. We show that in a spatially correlated disordered potential, the quantum motion of a bright soliton displays Anderson localization. The localization length can be much larger than the soliton size and could be observed experimentally.Comment: version accepted for publication in Phys. Rev. Let