P-T-t evolution of the Himalayan metamorphic core in the Mugu Karnali transect (Central Himalaya): preliminary data based on calculations of pseudosections

Abstract HKT-ISTP 2013 A

The Role of Inverse Compton Scattering in Solar Coronal Hard X-ray and Gamma-ray Sources

Coronal hard X-ray (HXR) and continuum gamma-ray sources associated with the impulsive phase of solar flares have been the subject of renewed interest in recent years. They have been interpreted in terms of thin-target, nonthermal bremsstrahlung emission. This interpretation has led to rather extreme physical requirements in some cases. For example, in one case, essentially all of the electrons in the source must be accelerated to nonthermal energies to account for the coronal HXR source. In other cases, the extremely hard photon spectra of the coronal continuum gamma-ray emission suggest that the low energy cutoff of the electron energy distribution lies in the MeV energy range. Here we consider the role of inverse Compton scattering (ICS) as an alternate emission mechanism in both the ultra- and mildly relativistic regimes. It is known that relativistic electrons are produced during powerful flares; these are capable of up-scattering soft photospheric photons to HXR and gamma-ray energies. Previously overlooked is the fact that mildly relativistic electrons, generally produced in much greater numbers in flares of all sizes, can up-scatter EUV/SXR photons to HXR energies. We also explore ICS on anisotropic electron distributions and show that the resulting emission can be significantly enhanced over an isotropic electron distribution for favorable viewing geometries. We briefly review results from bremsstrahlung emission and reconsider circumstances under which nonthermal bremsstrahlung or ICS would be favored. Finally, we consider a selection of coronal HXR and gamma-ray events and find that in some cases the ICS is a viable alternative emission mechanism

The use of mobile phones for skin tumor screening

A lot of importance is attributed to mobile telemedicine these days, a topic that encompasses a wide and ever growing range of applications. Small, handheld devices such as camera mobile phones have come into every day use providing technically sophisticated tasks on a user-friendly level and can therefore be easily used in various fields of telemedicine. Dermatology is a perfect candidate for the use of telemedicine tools in general, as well as mobile devices in particular. The unique aspect of mobile teledermatology is that this system represents a filtering, or triage system, allowing a sensitive approach for the management of patients with emergent skin diseases. In order to investigate the feasibility of teleconsultation using a new generation of cellular phones, a clinical study to evaluate the accuracy of online diagnosis of skin tumours was conducted. Teledermoscopy represents a recent development of teledermatology that might add up additional information in the diagnosis of pigmented skin lesions. Teledermatology, mobile as well as stationary, can advance the reliability of diagnosis by expert consultations without expensive and time-consuming relocations. Consequently, the quality of patient's care can be raised and the costs of the health care system can be reduced

The sub-arcsecond hard X-ray structure of loop footpoints in a solar flare

The newly developed X-ray visibility forward fitting technique is applied to Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) data of a limb flare to investigate the energy and height dependence on sizes, shapes, and position of hard X-ray chromospheric footpoint sources. This provides information about the electron transport and chromospheric density structure. The spatial distribution of two footpoint X-ray sources is analyzed using PIXON, Maximum Entropy Method, CLEAN and visibility forward fit algorithms at nonthermal energies from $\sim 20$ to $\sim 200$ keV. We report, for the first time, the vertical extents and widths of hard X-ray chromospheric sources measured as a function of energy for a limb event. Our observations suggest that both the vertical and horizontal sizes of footpoints are decreasing with energy. Higher energy emission originates progressively deeper in the chromosphere consistent with downward flare accelerated streaming electrons. The ellipticity of the footpoints grows with energy from $\sim 0.5$ at $\sim 20$ keV to $\sim 0.9$ at $\sim 150$ keV. The positions of X-ray emission are in agreement with an exponential density profile of scale height $\sim 150$~km. The characteristic size of the hard X-ray footpoint source along the limb is decreasing with energy suggesting a converging magnetic field in the footpoint. The vertical sizes of X-ray sources are inconsistent with simple collisional transport in a single density scale height but can be explained using a multi-threaded density structure in the chromosphere.Comment: 7 pages, 7 figures, submitted to Ap

Determination of hydraulic parameters in experimental soil columns from the southeast of Buenos Aires province

La cuenca del Río Quequén Grande constituye una región representativa de los sistemas agrícolas pampeanos. El acuífero en esta región es la principal fuente de abastecimiento de agua para todos los usos, lo que pone de manifiesto la importancia de desarrollar los elementos necesarios para el estudio de la movilidad de los contaminantes a través de los suelos hacia la zona saturada. El objetivo del presente trabajo fue obtener parámetros hidráulicos bajo condiciones de saturación en columnas intactas de distintos tipos de suelos de la región, contemplando suelos de uso agrícola y natural. Se estudiaron dos series de suelo: Serie Azul y Serie Semillero Buck, con muestras tomadas en dos sectores próximos a las localidades de Lobería y La Dulce, respectivamente. Las columnas fueron eluidas con una solución acuosa de iones cloruro y se midió el incremento progresivo de conductividad. A partir de las curvas de arribo obtenidas, se ajustó la ecuación de transporte, obteniendo los valores de dispersividad y porosidad. Dichos parámetros no presentaron diferencias significativas según el uso para los suelos de Lobería, de textura franco arcillosa, indicando que la labranza no produciría modificaciones evidentes en el perfil del suelo. En La Dulce, donde los suelos poseen una textura más arenosa, los parámetros variaron según el uso del suelo, presentando una mayor dispersividad y menor porosidad del suelo bajo explotación agrícola extensiva.The Quequén Grande river basin is representative of the farming systems from the Pampas region. The aquifer is the main source of water supply for all uses, which highlights the importance to study the mobility of contaminants through the soil to the saturated zone. The aim of this study was to obtain hydraulic parameters of different soil types in the region according to land use (agricultural and natural) under saturated conditions. Two study areas were selected close to the cities La Dulce (Azul Series Soil) and Lobería (Semillero Buck Series Soil), as representatives of the dominant soil types in this area. The columns were eluted with an aqueous solution containing chloride ions and the progressive increase was measured at the end of the column. From the experimental data the breakthrough curve was adjusted using MATLAB software while dispersivity and porosity values were determined from modeled data. These parameters did not differ significantly in Lobería, so it is assumed that tillage does not produce significant changes in the soil profile. Conversely, in La Dulce land use affects the hydraulic properties of the soil leading to lower porosity and higher dispersivity values in soils under tillage use.Fil: Grondona, Sebastián I.. Universidad Nacional de Mar del PlataFil: Martínez, Daniel E.. Universidad Nacional de Mar del PlataFil: Benavente, Miguel. Universidad Nacional de Mar del PlataFil: Gonzalez, Mariana. Universidad Nacional de Mar del PlataFil: Massone, Héctor E.. Universidad Nacional de Mar del PlataFil: Miglioranza, Karina S. B.. Universidad Nacional de Mar del Plat

Forward fitting STIX visibilities

Aims. We seek to determine to what extent the problem of forward fitting visibilities measured by the Spectrometer/Telescope Imaging X-rays (STIX) on board Solar Orbiter becomes more challenging with respect to the same problem in the case of previous hard X-ray solar imaging missions. In addition, we aim to identify an effective optimization scheme for parametric imaging for STIX. Methods. This paper introduces a global search optimization for forward-fitting STIX visibilities and compares its effectiveness with respect to the standard simplex-based optimization used so far for the analysis of visibilities measured by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). We made this comparison by considering experimental visibilities measured by both RHESSI and STIX, as weel as synthetic visibilities generated by accounting for the STIX signal formation model. Results. We found that among the three global search algorithms for parametric imaging, particle swarm optimization (PSO) exhibits the best performances in terms of both stability and computational effectiveness. This method is as reliable as the simplex method in the case of RHESSI visibilities. However, PSO is significantly more robust when applied to STIX simulated and experimental visibilities. Conclusions. A standard optimization based on local search of minima is not effective enough for forward-fitting the few visibilities sampled by STIX in the spatial frequency plane. Therefore, more sophisticated optimization schemes based on global search must be introduced for parametric imaging in the case of the Solar Orbiter X-ray telescope. The forward-fitting routine based on PSO proved to be significantly robust and reliable, and it could be considered as an effective candidate tool for parametric imaging in the STIX context

Melanoma Screening with Cellular Phones

Background. Mobile teledermatology has recently been shown to be suitable for teledermatology despite limitations in image definition in preliminary studies. The unique aspect of mobile teledermatology is that this system represents a filtering or triage system, allowing a sensitive approach for the management of patients with emergent skin diseases. Methodology/Principal Findings. In this study we investigated the feasibility of teleconsultation using a new generation of cellular phones in pigmented skin lesions. 18 patients were selected consecutively in the Pigmented Skin Lesions Clinic of the Department of Dermatology, Medical University of Graz, Graz (Austria). Clinical and dermoscopic images were acquired using a Sony Ericsson with a built-in two-megapixel camera. Two teleconsultants reviewed the images on a specific web application (http://www.dermahandy.net/default.asp) where images had been uploaded in JPEG format. Compared to the face-to-face diagnoses, the two teleconsultants obtained a score of correct telediagnoses of 89% and of 91.5% reporting the clinical and dermoscopic images, respectively. Conclusions/Significance. The present work is the first study performing mobile teledermoscopy using cellular phones. Mobile teledermatology has the potential to become an easy applicable tool for everyone and a new approach for enhanced self-monitoring for skin cancer screening in the spirit of the eHealth program of the European Commission Information for Society and Media

Avaliação algimétrica e sinérgica em cães tratados pela levomepromazina, induzidos pelo tiopental e mantidos pelo sevofluorano, pré-tratados ou não pelo butorfanol

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