50 resultados para K-P ATOM


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The T2K collaboration reports a precision measurement of muon neutrino disappearance with an off-axis neutrino beam with a peak energy of 0.6 GeV. Near detector measurements are used to constrain the neutrino flux and cross section parameters. The Super-Kamiokande far detector, which is 295 km downstream of the neutrino production target, collected data corresponding to 3.01×1020 protons on target. In the absence of neutrino oscillations, 205±17 (syst.) events are expected to be detected and only 58 muon neutrino event candidates are observed. A fit to the neutrino rate and energy spectrum assuming three neutrino flavors, normal mass hierarchy and θ23≤π/4 yields a best-fit mixing angle sin2(2θ23)=1.000 and mass splitting |Δm232|=2.44×10−3 eV2/c4. If θ23≥π/4 is assumed, the best-fit mixing angle changes to sin2(2θ23)=0.999 and the mass splitting remains unchanged.

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The T2K experiment has observed electron neutrino appearance in a muon neutrino beam produced 295 km from the Super-Kamiokande detector with a peak energy of 0.6 GeV. A total of 28 electron neutrino events were detected with an energy distribution consistent with an appearance signal, corresponding to a significance of 7.3σ when compared to 4.92 ± 0.55 expected background events. In the PMNS mixing model, the electron neutrino appearance signal depends on several parameters including three mixing angles θ12, θ23, θ13, a mass difference Δm232 and a CP violating phase δCP. In this neutrino oscillation scenario, assuming |Δm232|=2.4×10−3 eV2, sin2θ23=0.5, δCP=0, and Δm232>0 (Δm232<0), a best-fit value of sin22θ13 = 0.140+0.038−0.032 (0.170+0.045−0.037) is obtained.

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Hellas basin is a large impact basin situated in the southern highlands of Mars. The north-western part of the basin has the lowest elevation (-7.5 km) on the planet and contains a possibly unique terrain type, which we informally call “banded terrain”. The banded terrain is made up of smooth-looking banded deposits that display signs of viscous behavior and a paucity of superimposed impact craters. In this study, we use newly acquired high spatial resolution images from the High Resolution Imaging Science Experiment (HiRISE) in addition to existing datasets to characterize the geomorphology, the morphometry and the architecture of the banded terrain. The banded terrain is generally confined to the NW edge of the Alpheus Colles plateau. The individual bands are ~3–15 km-long, ~0.3 km-wide and are separated by narrow inter-band depressions, which are ~65 m-wide and ~10 m-deep. The bands display several morphologies that vary from linear to concentric forms. Morphometric analysis reveals that the slopes along a given linear or lobate band ranges from 0.5° to 15° (average~6°), whereas the concentric bands are located on flatter terrain (average slope~2–3°). Crater-size frequency analysis yields an Amazonian-Hesperian boundary crater retention age for the terrain (~3 Gyr), which together, with the presence of very few degraded craters, either implies a recent emplacement, resurfacing, or intense erosion. The apparent sensitivity to local topography and preference for concentrating in localized depressions is compatible with deformation as a viscous fluid. In addition, the bands display clear signs of degradation and slumping at their margins along with a suite of other features that include fractured mounds, polygonal cracks at variable size-scales, and knobby/hummocky textures. Together, these features suggest an ice-rich composition for at least the upper layers of the terrain, which is currently being heavily modified through loss of ice and intense weathering, possibly by wind.

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Aims. 67P/Churyumov-Gerasimenko is the target comet of the ESA’s Rosetta mission. After commissioning at the end of March 2014, the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) onboard Rosetta, started imaging the comet and its dust environment to investigate how they change and evolve while approaching the Sun. Methods. We focused our work on Narrow Angle Camera (NAC) orange images and Wide Angle Camera (WAC) red and visible-610 images acquired between 2014 March 23 and June 24 when the nucleus of 67P was unresolved and moving from approximately 4.3 AU to 3.8 AU inbound. During this period the 67P – Rosetta distance decreased from 5 million to 120 thousand km. Results. Through aperture photometry, we investigated how the comet brightness varies with heliocentric distance. 67P was likely already weakly active at the end of March 2014, with excess flux above that expected for the nucleus. The comet’s brightness was mostly constant during the three months of approach observations, apart from one outburst that occurred around April 30 and a second increase in flux after June 20. Coma was resolved in the profiles from mid-April. Analysis of the coma morphology suggests that most of the activity comes from a source towards the celestial north pole of the comet, but the outburst that occurred on April 30 released material in a different direction.

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Aims. Approach observations with the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) experiment onboard Rosetta are used to determine the rotation period, the direction of the spin axis, and the state of rotation of comet 67P’s nucleus. Methods. Photometric time series of 67P have been acquired by OSIRIS since the post wake-up commissioning of the payload in March 2014. Fourier analysis and convex shape inversion methods have been applied to the Rosetta data as well to the available ground-based observations. Results. Evidence is found that the rotation rate of 67P has significantly changed near the time of its 2009 perihelion passage, probably due to sublimation-induced torque. We find that the sidereal rotation periods P1 = 12.76129 ± 0.00005 h and P2 = 12.4043 ± 0.0007 h for the apparitions before and after the 2009 perihelion, respectively, provide the best fit to the observations. No signs of multiple periodicity are found in the light curves down to the noise level, which implies that the comet is presently in a simple rotation state around its axis of largest moment of inertia. We derive a prograde rotation model with spin vector J2000 ecliptic coordinates λ = 65° ± 15°, β = + 59° ± 15°, corresponding to equatorial coordinates RA = 22°, Dec = + 76°. However, we find that the mirror solution, also prograde, at λ = 275° ± 15°, β = + 50° ± 15° (or RA = 274°, Dec = + 27°), is also possible at the same confidence level, due to the intrinsic ambiguity of the photometric problem for observations performed close to the ecliptic plane.

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The interior of Hellas Basin displays a complex landscape and a variety of geomorphological domains. One of these domains, the enigmatic banded terrain covers much of the northwestern part of the basin. We use high-resolution (CTX and HiRISE) Digital Terrain Models to show that most of the complex viscous flowing behavior exhibited by the banded terrain is controlled by topography and flow-like interactions between neighboring banded terrain. Furthermore, the interior of the basin hosts several landforms suggestive of the presence of near-surface ice, which include polygonal patterns with elongated pits, scalloped depressions, isolated mounds and collapse structures. We suggest that thermal contraction cracking and sublimation of near-surface ice are responsible for the formation and the development of most of the ice-related landforms documented in Hellas. The relatively pristine form, lack of superposed craters, and strong association with the banded terrain, suggest an Amazonian (<3 Ga) age of formation for these landforms. Finally, relatively high surface pressures (above the triple point of water) expected in Hellas and summer-time temperatures often exceeding the melting point of water ice suggest that the basin may have recorded relatively “temperate” climatic conditions compared to other places on Mars. Therefore, the potentially ice-rich banded terrain may have deformed with lower viscosity and stresses compared to other locations on Mars, which may account for its unique morphology.

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Hellas basin acts as a major sink for the southern highlands of Mars and is likely to have recorded several episodes of sedimentation and erosion. The north-western part of the basin displays a potentially unique Amazonian landscape domain in the deepest part of Hellas, called “banded terrain”, which is a deposit characterized by an alternation of narrow band shapes and inter-bands displaying a sinuous and relatively smooth surface texture suggesting a viscous flow origin. Here we use high-resolution (HiRISE and CTX) images to assess the geomorphological interaction of the banded terrain with the surrounding geomorphologic domains in the NW interior of Hellas to gain a better understanding of the geological evolution of the region as a whole. Our analysis reveals that the banded terrain is associated with six geomorphologic domains: a central plateau named Alpheus Colles, plain deposits (P1 and P2), reticulate (RT1 and RT2) and honeycomb terrains. Based on the analysis of the geomorphology of these domains and their cross-cutting relationships, we show that no widespread deposition post-dates the formation of the banded terrain, which implies that this domain is the youngest and latest deposit of the interior of Hellas. Therefore, the level of geologic activity in the NW Hellas during the Amazonian appears to have been relatively low and restricted to modification of the landscape through mechanical weathering, aeolian and periglacial processes. Thermophysical data and cross-cutting relationships support hypotheses of modification of the honeycomb terrain via vertical rise of diapirs such as ice diapirism, and the formation of the plain deposits through deposition and remobilization of an ice-rich mantle deposit. Finally, the observed gradual transition between honeycomb and banded terrain suggests that the banded terrain may have covered a larger area of the NW interior of Hellas in the past than previously thought. This has implications on the understanding of the evolution of the deepest part of Hellas.

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There are large variations in the incidence, registration methods and reported causes of sudden cardiac arrest/sudden cardiac death (SCA/SCD) in competitive and recreational athletes. A crucial question is to which degree these variations are genuine or partly due to methodological incongruities. This paper discusses the uncertainties about available data and provides comprehensive suggestions for standard definitions and a guide for uniform registration parameters of SCA/SCD. The parameters include a definition of what constitutes an 'athlete', incidence calculations, enrolment of cases, the importance of gender, ethnicity and age of the athlete, as well as the type and level of sporting activity. A precise instruction for autopsy practice in the case of a SCD of athletes is given, including the role of molecular samples and evaluation of possible doping. Rational decisions about cardiac preparticipation screening and cardiac safety at sport facilities requires increased data quality concerning incidence, aetiology and management of SCA/SCD in sports. Uniform standard registration of SCA/SCD in athletes and leisure sportsmen would be a first step towards this goal.

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PURPOSE: Patients with chronic depression (CD) by definition respond less well to standard forms of psychotherapy and are more likely to be high utilizers of psychiatric resources. Therefore, the aim of this guidance paper is to provide a comprehensive overview of current psychotherapy for CD. The evidence of efficacy is critically reviewed and recommendations for clinical applications and research are given. METHODS: We performed a systematic literature search to identify studies on psychotherapy in CD, evaluated the retrieved documents and developed evidence tables and recommendations through a consensus process among experts and stakeholders. RESULTS: We developed 5 recommendations which may help providers to select psychotherapeutic treatment options for this patient group. The EPA considers both psychotherapy and pharmacotherapy to be effective in CD and recommends both approaches. The best effect is achieved by combined treatment with psychotherapy and pharmacotherapy, which should therefore be the treatment of choice. The EPA recommends psychotherapy with an interpersonal focus (e.g. the Cognitive Behavioural Analysis System of Psychotherapy [CBASP]) for the treatment of CD and a personalized approach based on the patient's preferences. DISCUSSION: The DSM-5 nomenclature of persistent depressive disorder (PDD), which includes CD subtypes, has been an important step towards a more differentiated treatment and understanding of these complex affective disorders. Apart from dysthymia, ICD-10 still does not provide a separate entity for a chronic course of depression. The differences between patients with acute episodic depression and those with CD need to be considered in the planning of treatment. Specific psychotherapeutic treatment options are recommended for patients with CD. CONCLUSION: Patients with chronic forms of depression should be offered tailored psychotherapeutic treatments that address their specific needs and deficits. Combination treatment with psychotherapy and pharmacotherapy is the first-line treatment recommended for CD. More research is needed to develop more effective treatments for CD, especially in the longer term, and to identify which patients benefit from which treatment algorithm.