455 research outputs found

    Radiation and magnetic field effects on new semiconductor power devices for HL-LHC experiments

    Full text link
    The radiation hardness of commercial Silicon Carbide and Gallium Nitride power MOSFETs is presented in this paper, for Total Ionizing Dose effects and Single Event Effects, under gamma, neutrons, protons and heavy ions. Similar tests are discussed for commercial DC-DC converters, also tested in operation under magnetic field

    Caracterização de lesões de pele em imagens digitais a partir da máquina de vetor de suporte

    Get PDF
    Este trabalho apresenta um método para a caracterização das lesões de pele, a partir das características da regra ABCD (assimetria, borda, cor e diâmetro) e análise de textura. As características ABCD são obtidas de acordo com o dermatologista e a textura das imagens é definida pela sua dimensão fractal, por meio do método box-counting. As características de assimetria e textura extraídas das imagens são utilizadas como entradas para o classificador SVM (Máquina de Vetor de Suporte), que é uma técnica baseada em aprendizado estatístico, utilizada para o reconhecimento de padrões em imagens. O SVM classifica a assimetria das lesões em simétrica ou assimétrica e a textura das lesões em lisa ou rugosa. Todas as informações referentes as características extraídas da lesão são passadas ao dermatologista com o intuito de auxiliá-lo no diagnóstico

    Aging measurements on triple-GEM detectors operated with CF4-based gas mixtures

    Get PDF
    We present the results of a global irradiation test of full size triple-GEM detectors operated with CF 4 -based gas mixtures. This study has been performed in the framework of an R&D activity on detectors for the innermost region of the first muon station of the LHCb experiment. The prototypes have been irradiated at the Calliope facility of the ENEA-Casaccia with a high intensity 1.25 MeV γ 60 Co source. After the irradiation test the detectors performances have been measured with X-rays and with a 3 GeV pion beam at CERN. A SEM analysis on several samples of the detectors has been performed to complete the understanding of the physical processes occurring in a GEM detector during a strong irradiation

    The CMS ECAL Barrel HV system

    Get PDF
    The CMS electromagnetic calorimeter (ECAL) comprises 75848 scintillating lead tungstate crystals. 61200 crystals are contained in the ECAL Barrel section and are read out by avalanche photodiode (APD) with internal gain of about 50. This gain is achieved with a high voltage (HV) of about 400 Volts. The gain stability requirement implies a supply voltage stable to within 0.01%. We describe our experience with the installed Barrel HV power supply system, which has been used for data taking since 2008

    Surgical site infection after caesarean section. Space for post-discharge surveillance improvements and reliable comparisons

    Get PDF
    Surgical site infections (SSI) after caesarean section (CS) represent a substantial health system concern. Surveying SSI has been associated with a reduction in SSI incidence. We report the findings of three (2008, 2011 and 2013) regional active SSI surveillances after CS in community hospital of the Latium region determining the incidence of SSI. Each CS was surveyed for SSI occurrence by trained staff up to 30 post-operative days, and association of SSI with relevant characteristics was assessed using binomial logistic regression. A total of 3,685 CS were included in the study. A complete 30 day post-operation follow-up was achieved in over 94% of procedures. Overall 145 SSI were observed (3.9% cumulative incidence) of which 131 (90.3%) were superficial and 14 (9.7%) complex (deep or organ/space) SSI; overall 129 SSI (of which 89.9% superficial) were diagnosed post-discharge. Only higher NNIS score was significantly associated with SSI occurrence in the regression analysis. Our work provides the first regional data on CS-associated SSI incidence, highlighting the need for a post-discharge surveillance which should assure 30 days post-operation to not miss data on complex SSI, as well as being less labour intensive

    Análise e caracterização de lesões de pele para auxílio ao diagnóstico médico

    Get PDF
    Neste capítulo, propõe-se uma metodologia híbrida para detectar e extrair os contornos de lesões de pele a partir de imagens, bem como a definição de características usualmente utilizadas no diagnóstico de lesões. O método de segmentação por divisão e união (Split and Merge) foi adotado para detectar a lesão e obter o seu contorno inicial. Em seguida, este contorno é refinado pelo modelo de contorno ativo tradicional. Características da lesão usadas na regra ABCD, são definidas a partir do contorno refinado. Os resultados experimentais indicam que o método proposto é promissor para detectar as áreas com lesão e extrair seus contornos a partir de imagens, mantendo suas características

    Uma metodologia híbrida para segmentação de lesões de pele

    Get PDF
    Computer aided methods are widespread demanded in medical applications. As such, methodologies to automatic extract contours are desired to aid the automatic diagnosis of skin lesions. In this work, we propose a hybrid method to detect and extract skin lesion contours from dermatoscopic images. In the proposed method, to obtain the contour that includes all lesion regions, the region growing technique, based on a Quadtree implementation, is used to extract an initial contour. Afterwards, this contour is refined by using a traditional active contour model. Experimental results indicate that the proposed method is promising to detect skin lesion areas and to extract their contours from dermatoscopic images. Actually, the extracted contours maintain the original lesion features that are usually used in their diagnosis. Additionally, the results allow concluding that the method is able to detect lesion regions even in images with strong noise, like in images of the scalp

    Metal transfer to sediments, invertebrates and fish following waterborne exposure to silver nitrate or silver sulfide nanoparticles in an indoor stream mesocosm

    Get PDF
    The fate of engineered nanomaterials in ecosystems is unclear. An aquatic stream mesocosm explored the fate and bioaccumulation of silver sulfide nanoparticles (AgS NPs) compared to silver nitrate (AgNO). The aims were to determine the total Ag in water, sediment and biota, and to evaluate the bioavailable fractions of silver in the sediment using a serial extraction method. The total Ag in the water column from a nominal daily dose of 10 μg L of Ag for the AgNO or AgS NP treatments reached a plateau of around 13 and 12 μg L, respectively, by the end of the study. Similarly, the sediment of both Ag-treatments reached ~380 μg Ag kg, and with most of it being acid-extractable/labile. The biota accumulated 4–59 μg Ag g dw, depending on the type of Ag-treatment and organism. The oligochaete worm, Lumbriculus variegatus, accumulated Ag from the AgS exposure over time, which was similar to the AgNO treatment by the end of the experiment. The planarian, Girardia tigrina, and the chironomid larva, Chironomus riparius, showed much higher Ag concentrations than the oligochaete worms; and with a clearer time-dependent statistically significant Ag accumulation relative to the untreated controls. For the pulmonate snail, Physa acuta, bioaccumulation of Ag from AgNO and AgS NP exposures was observed, but was lower from the nano treatment. The AgNO exposure caused appreciable Ag accumulation in the water flea, Daphnia magna, but accumulation was higher in the AgS NP treatment (reaching 59 μg g dw). In the rainbow trout, Oncorhynchus mykiss, AgNO, but not AgS NPs, caused total Ag concentrations to increase in the tissues. Overall, the study showed transfer of total Ag from the water column to the sediment, and Ag bioaccumulation in the biota, with Ag from AgS NP exposure generally being less bioavailable than that from AgNO.This work was supported by the project NanoFASE (Nanomaterial Fate and Speciation in the Environment), financed by the European Union's Horizon 2020 research and innovation programme under grant agreement no 646002. RDH was partly supported by NanoHarmony under grant agreement 885931 in Horizon 2020 while redrafting the main text. PVS was awarded with a PhD grant (SFRH/BD/51571/2014) by FCT – Fundação para a Ciência e a Tecnologia. SL and PVS received additional financial support from FCT/MCTES, through national funds, to CESAM (UIDP/50017/2020+UIDB/50017/2020+ LA/P/0094/2020)

    Uma metodologia híbrida para segmentação de lesões de pele

    Get PDF
    Computer aided methods are widespread demanded in medical applications. As such, methodologies to automatic extract contours are desired to aid the automatic diagnosis of skin lesions. In this work, we propose a hybrid method to detect and extract skin lesion contours from dermatoscopic images. In the proposed method, to obtain the contour that includes all lesion regions, the region growing technique, based on a Quadtree implementation, is used to extract an initial contour. Afterwards, this contour is refined by using a traditional active contour model. Experimental results indicate that the proposed method is promising to detect skin lesion areas and to extract their contours from dermatoscopic images. Actually, the extracted contours maintain the original lesion features that are usually used in their diagnosis. Additionally, the results allow concluding that the method is able to detect lesion regions even in images with strong noise, like in images of the scalp
    corecore