1,225 research outputs found

    Characterisation of AMS H35 HV-CMOS monolithic active pixel sensor prototypes for HEP applications

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    Monolithic active pixel sensors produced in High Voltage CMOS (HV-CMOS) technology are being considered for High Energy Physics applications due to the ease of production and the reduced costs. Such technology is especially appealing when large areas to be covered and material budget are concerned. This is the case of the outermost pixel layers of the future ATLAS tracking detector for the HL-LHC. For experiments at hadron colliders, radiation hardness is a key requirement which is not fulfilled by standard CMOS sensor designs that collect charge by diffusion. This issue has been addressed by depleted active pixel sensors in which electronics are embedded into a large deep implantation ensuring uniform charge collection by drift. Very first small prototypes of hybrid depleted active pixel sensors have already shown a radiation hardness compatible with the ATLAS requirements. Nevertheless, to compete with the present hybrid solutions a further reduction in costs achievable by a fully monolithic design is desirable. The H35DEMO is a large electrode full reticle demonstrator chip produced in AMS 350 nm HV-CMOS technology by the collaboration of Karlsruher Institut f\"ur Technologie (KIT), Institut de F\'isica d'Altes Energies (IFAE), University of Liverpool and University of Geneva. It includes two large monolithic pixel matrices which can be operated standalone. One of these two matrices has been characterised at beam test before and after irradiation with protons and neutrons. Results demonstrated the feasibility of producing radiation hard large area fully monolithic pixel sensors in HV-CMOS technology. H35DEMO chips with a substrate resistivity of 200Ω\Omega cm irradiated with neutrons showed a radiation hardness up to a fluence of 101510^{15}neq_{eq}cm2^{-2} with a hit efficiency of about 99% and a noise occupancy lower than 10610^{-6} hits in a LHC bunch crossing of 25ns at 150V

    Monoclonal antibodies against the human lymphocyte differentiation antigen CD 76 bind to gangliosides

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    AbstractTwo monoclonal antibodies, HD 66 and CRIS-4, by which the new CD 76 B-cell-associated cluster was defined, bound to several gangliosides (sialic acid containing glycolipids) of different polarity. One of the gangliosides recognized by HD 66 could be identified as NeuAcα2-6Galβl-4GlcNAcβl-3Galβl-4Glc-βl-l'Cer. This antigen was enzymatically synthesized. Sialidase treatment of the ganglioside antigens abolished binding of HD 66 and CRIS-4

    Influence of continuous and intermittent water regimes on methane emissions from irrigated rice crops in southeast Brazil.

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    Irrigated rice crops in Brazil correspond to 35% of the total rice area and the preferred irrigation method is continuous flooding. In this study two water management systems ? continuous and intermittent flooding ? were monitored for the purpose of comparing their methane emission potential. Intermittent flooding was characterized by alternating flooding and draining periods during the rice cropping cycle. In both systems nitrogen fertilizers were applied twice (NPK and urea alone). Methane fluxes were determined using a closed chamber method (boxes 60x60 cm), and analyzed by GC-FID. Samples were collected from 4 boxes (2 boxes for each water management system) twice a week, for a weekly total of 46 samples. Measurements of air and soil temperature, soil and water pH, redox potential, plant biomass were done. After 104 days the accumulated fluxes resulted in a mean methane emission of 21.1 9 g CH4 m-2 d-1 under the continuous flooding regime and 23.9 g CH4 m-2 d-1 under the intermittent flooding regime. After the two N fertilizer application, methane fluxes decreased in all boxes, with a more marked reduction occurring in the intermittent regime stands. Total accumulated methane emissions, as well as grain yield, were evaluated for each water management system at the end of the cropping season, showing 13% higher productivity in the field under intermittent flooding system. The objectives of the present study were (i) to improve methane emission estimates and compare the emission potential of traditionally managed crop systems and (ii) to study the possibility of minimizing water consumption and the influence on the methane fluxes without deleterious effects to the crop

    Prototyping of an HV-CMOS demonstrator for the High Luminosity-LHC upgrade

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    HV-CMOS sensors can offer important advantages in terms of material budget, granularity and cost for large area tracking systems in high energy physics experiments. This article presents the design and simulated results of an HV-CMOS pixel demonstrator for the High Luminosity-LHC. The pixel demonstrator has been designed in the 0.35 μm HV-CMOS process from ams AG and submitted for fabrication through an engineering run. To improve the response of the sensor, different wafers with moderate to high substrate resistivities are used to fabricate the design. The prototype consists of four large analog and standalone matrices with several pixel flavours, which are all compatible for readout with the FE-I4 ASIC. Details about the matrices and the pixel flavours are provided in this article

    Emissão de N2O de um latossolo vermelho sob consórcio sorgo e braquiária no Cerrado.

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    O objetivo desse trabalho foi avaliar os fluxos de N2O em Latossolo Vermelho sob consórcio de sorgo (Sorghum bicolor) e braquiária piatã (Brachiaria brizantha cv. Piatã) em sucessão à soja em área de sequeiro, correlacionandoos com dados de precipitação, temperatura e umidade do solo. O experimento foi conduzido na Embrapa Cerrados em blocos ao acaso com duas repetições. Os tratamentos foram constituídos por: sistema de lavoura contínua sob plantio direto (1), lavoura contínua sob plantio convencional (2) e sistema de integração lavoura pecuária (3), tendo o Cerrado Nativo como referência. O plantio de sorgo foi realizado em consórcio com Piatã, após a colheita da soja. As amostras de N2O foram coletadas no período de 21/03/2014 a 04/07/2014 em câmaras do tipo estática fechada e analisadas em cromatógrafo gasoso. O fluxo de N2O foi maior logo após o plantio, a adubação de cobertura e precipitação para todos os sistemas de manejo avaliados. Os maiores fluxos foram verificados no sistema 2 com valores médios de 90,55 μg m-2 h-1, enquanto que nos sistemas 1 e 3 os fluxos médios foram 46,49 e 45,29 μg m-2 h-1, respectivamente

    Design and characterization of the monolithic matrices of the H35DEMO chip

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    Standard tone stability as a manipulation of precision in the oddball paradigm: Modulation of prediction error responses to fixed-probability deviants

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    Electrophysiological sensory deviance detection signals, such as the mismatch negativity (MMN), have been interpreted from the predictive coding framework as manifestations of prediction error (PE). From a frequentist perspective of the classic oddball paradigm, deviant stimuli are unexpected because of their low probability. However, the amount of PE elicited by a stimulus can be dissociated from its probability of occurrence: when the observer cannot make confident predictions, any event holds little surprise value, no matter how improbable. Here we tested the hypothesis that the magnitude of the neural response elicited to an improbable sound (D) would scale with the precision of the prediction derived from the repetition of another sound (S), by manipulating repetition stability. We recorded the Electroencephalogram (EEG) from 20 participants while passively listening to 4 types of isochronous pure tone sequences differing in the probability of the S tone (880 Hz) while holding constant the probability of the D tone [1,046 Hz; p(D) = 1/11]: Oddball [p(S) = 10/11]; High confidence (7/11); Low confidence (4/11); and Random (1/11). Tones of 9 different frequencies were equiprobably presented as fillers [p(S) C p(D) C p(F) = 1]. Using a mass-univariate non-parametric, cluster-based correlation analysis controlling for multiple comparisons, we found that the amplitude of the deviant-elicited ERP became more negative with increasing S probability, in a time-electrode window consistent with the MMN (ca. 120- 200 ms; frontal), suggesting that the strength of a PE elicited to an improbable event indeed increases with the precision of the predictive model

    Sensitisation to Act 2d in patientsallergic to Alternaria alternanta: an epiphenomenom without clinical significance?

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    In the last few years, the introduction of microarrays in the diagnosis of type I allergy is allowing the clinicians to have a much more accurate picture of their allergenic profile. However, the simultaneous measurement of specific IgE to multiple molecules can show unexpected sensitisations, without knowing their clinical relevance. For instance, we have been observing a high prevalence (74%) of sensitisation to Act d 2 (the thaumatin of kiwifruit) in patients sensitised to Alt a 1 (major allergen of Alternaria alternata) with a confirmed allergy to this mould. The aim of the present study was to clarify if there was any clinical relevance in this finding
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