5,892 research outputs found

    Characterization of Thin p-on-p Radiation Detectors with Active Edges

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    Active edge p-on-p silicon pixel detectors with thickness of 100 őľ\mum were fabricated on 150 mm Float zone silicon wafers at VTT. By combining measured results and TCAD simulations, a detailed study of electric field distributions and charge collection performances as a function of applied voltage in a p-on-p detector was carried out. A comparison with the results of a more conventional active edge p-on-n pixel sensor is presented. The results from 3D spatial mapping show that at pixel-to-edge distances less than 100 őľ\mum the sensitive volume is extended to the physical edge of the detector when the applied voltage is above full depletion. The results from a spectroscopic measurement demonstrate a good functionality of the edge pixels. The interpixel isolation above full depletion and the breakdown voltage were found to be equal to the p-on-n sensor while lower charge collection was observed in the p-on-p pixel sensor below 80 V. Simulations indicated this to be partly a result of a more favourable weighting field in the p-on-n sensor and partly of lower hole lifetimes in the p-bulk.Comment: 23 pages, 16 figures, 1 tabl

    Technical note : Comparison of methane ebullition modelling approaches used in terrestrial wetland models

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    Emission via bubbling, i.e. ebullition, is one of the main methane (CH4) emission pathways from wetlands to the atmosphere. Direct measurement of gas bubble formation, growth and release in the peat-water matrix is challenging and in consequence these processes are relatively unknown and are coarsely represented in current wetland CH4 emission models. In this study we aimed to evaluate three ebullition modelling approaches and their effect on model performance. This was achieved by implementing the three approaches in one process-based CH4 emission model. All the approaches were based on some kind of threshold: either on CH4 pore water concentration (ECT), pressure (EPT) or free-phase gas volume (EBG) threshold. The model was run using 4 years of data from a boreal sedge fen and the results were compared with eddy covariance measurements of CH4 fluxes. Modelled annual CH4 emissions were largely unaffected by the different ebullition modelling approaches; however, temporal variability in CH4 emissions varied an order of magnitude between the approaches. Hence the ebullition modelling approach drives the temporal variability in modelled CH4 emissions and therefore significantly impacts, for instance, high-frequency (daily scale) model comparison and calibration against measurements. The modelling approach based on the most recent knowledge of the ebullition process (volume threshold, EBG) agreed the best with the measured fluxes (R-2 = 0.63) and hence produced the most reasonable results, although there was a scale mismatch between the measurements (ecosystem scale with heterogeneous ebullition locations) and model results (single horizontally ho-mogeneous peat column). The approach should be favoured over the two other more widely used ebullition modelling approaches and researchers are encouraged to implement it into their CH4 emission models.Peer reviewe

    Attitudes toward sad music are related to both preferential and contextual strategies

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    Music-related sadness and its paradoxical pleasurable aspects have puzzled researchers for decades. Previous studies have highlighted the positive effects of listening to sad music and the listening strategies that focus on mood-regulation. The present study explored people’s attitudes toward sad music by focusing on a representative sample of the Finnish population. Three hundred and fifty-eight participants rated their agreement with 30 statements concerning attitudes toward sad music. The ratings were subjected to factor analysis, resulting in 6 factors explaining 51% of the variance (RMSEA = 0.049). The factors were labeled Avoidance, Autobiographical, Revival, Appreciation, Intersubjective, and Amplification, and they were divided into 2 broad headings, preferential and contextual attitudes toward sad music. Contextual attitudes seemed to be ambiguous in terms of valence, whereas the preferential attitudes were more clearly identified in terms of positive/negative polarity. The results of the survey suggest that listening to sad music elicits a wide variety of responses that are not fully revealed in previous studies

    Simulation study of signal formation in position sensitive planar p-on-n silicon detectors after short range charge injection

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    Segmented silicon detectors (micropixel and microstrip) are the main type of detectors used in the inner trackers of Large Hadron Collider (LHC) experiments at CERN. Due to the high luminosity and eventual high fluence of energetic particles, detectors with fast response to fit the short shaping time of 20-25 ns and sufficient radiation hardness are required. Charge collection measurements carried out at the Ioffe Institute have shown a reversal of the pulse polarity in the detector response to short-range charge injection. Since the measured negative signal is about 30-60% of the peak positive signal, the effect strongly reduces the CCE even in non-irradiated detectors. For further investigation of the phenomenon the measurements have been reproduced by TCAD simulations. As for the measurements, the simulation study was applied for the p-on-n strip detectors similar in geometry to those developed for the ATLAS experiment and for the Ioffe Institute designed p-on-n strip detectors with each strip having a window in the metallization covering the p(+) implant, allowing the generation of electron-hole pairs under the strip implant. Red laser scans across the strips and the interstrip gap with varying laser diameters and Si-SiO2 interface charge densities (Q(f)) were carried out. The results verify the experimentally observed negative response along the scan in the interstrip gap. When the laser spot is positioned on the strip p(+) implant the negative response vanishes and the collected charge at the active strip increases respectively. The simulation results offer a further insight and understanding of the influence of the oxide charge density in the signal formation. The main result of the study is that a threshold value of Q(f), that enables negligible losses of collected charges, is defined. The observed effects and details of the detector response for different charge injection positions are discussed in the context of Ramo's theorem.Peer reviewe

    Lukivaikeuden tunnistamisen ja tuen merkitys oppilaan elämässä

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    Tiivistelmä. Lukivaikeus on yksi yleisimmistä oppimisvaikeuksista, joka ilmenee vaikeuksina sanantunnistuksessa ja oikeinkirjoitus- ja dekoodaustaidoissa. Teknisten taitojen vaikeudet voivat laajentua niin, että ongelmia esiintyy myös luetunymmärtämisessä ja tuottavassa kirjoittamisessa. Lukivaikeuteen liittyy myös päällekkäistyminen muiden oppimisvaikeuksien sekä mielenterveyden häiriöiden kanssa. Lukivaikeutta ennakoivat perinnölliset tekijät, sillä lukivaikeus esiintyy usein suvuittain. Vaikeudet fonologisessa tietoisuudessa, nopeassa sarjallisessa nimeämisessä sekä kirjainten tuntemisessa ennakoivat myös lukivaikeutta. Myös muut kielen kehittymiseen liittyvät ongelmat voivat ennakoida lukivaikeutta. Kouluissa lukivaikeus voidaan tunnistaa lukitestien avulla. Testit toteutetaan yleensä seulontana, jonka avulla tunnistetaan tuen tarpeessa olevat oppilaat. Suurin osa lukitesteistä on suunnattu koulupolun alkuun, mutta testejä on myös nuorille ja aikuisille. Testit arvioivat monipuolisesti lukemiseen liittyviä taitoja, jotta niistä saadaan mahdollisimman kattava kuva. Tunnistamisen jälkeen oppilaalle suunnitellaan yksilölliset tukimuodot, joiden vaikuttavuutta seurataan. Lukivaikeus voi vaikuttaa negatiivisesti motivaatioon ja mielen hyvinvointiin. Jatkuvat epäonnistumisen kokemukset heikentävät motivaatiota ja minäpystyvyyden tunnetta. Tukimuodot kohdentuvatkin lukitaitojen kohentamisen lisäksi myös metakognitiivisten taitojen sekä mielen hyvinvoinnin tukemiseen. Lukivaikeus on yhteydessä matalaan koulutustasoon. Lukivaikeus ei kuitenkaan itsessään ole este korkeakouluopintoihin tai akateemiseen menestykseen, mutta tutkimuksissa korostui tuen merkitys. Yksilöllisellä ja kohdennetulla tuella lukivaikeuden mahdollisia pitkittäisvaikutuksia pystytään lieventämään.The Importance of recognizing and supporting reading difficulties in a student’s life. Abstract. Dyslexia (or reading difficulty) is one of the most common learning difficulties, which manifests as difficulties in word recognition and spelling and decoding skills. Difficulties in technical skills can extend to problems with reading comprehension and productive writing. Dyslexia is also associated with an overlap with other learning disabilities as well as mental health problems. Genetic factors predict reading difficulties, as reading difficulties often occur in families. Difficulties in phonological awareness, rapid serial naming, and knowledge of letters can also anticipate reading difficulties. Other problems related to language development can also predict reading difficulties. In schools, reading difficulties can be identified through dyslexia tests. Tests are usually carried out as a screening process to identify students in need of support. Most of the tests are aimed at the beginning of the school path, but there are also tests for young people and adults. The tests evaluate a wide range of skills related to reading, so that they can provide the most comprehensive picture. After identification, student receives individual support, which’s effectiveness is monitored. Dyslexia can negatively affect motivation and mental well-being. Continuous experiences of failure weaken motivation and self-esteem. In addition to improving reading skills, reading support also focus on supporting metacognitive skills and mental well-being. Dyslexia is associated with a low level of education. However, dyslexia as such is not an obstacle to academic education or success, but research has highlighted the importance of support. With individual and well targeted support, the possible long-term effects of reading difficulties can be mitigated

    Towards a more explicit account of the transformation: Reply to comments on ‚ÄúAn integrative review of the enjoyment of sadness associated with music‚ÄĚ

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    Our integrative framework for explaining the enjoyment of sadness associated with music sparked a delightful number (13) of commentaries which challenge, stimulate, strengthen and shape the ideas we initially put forward. Here we organize our response around five central themes brought up by several commentators. These relate to questions about (a) the nature of sad music, (b) whether music can induce genuine sadness, (c) details of the transformation, (d) music as a technology for emotion regulation, and (e) broader implications and extensions.nonPeerReviewe

    Bayesian data integration and variable selection for pan‚Äźcancer survival prediction using protein expression data

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    Accurate prognostic prediction using molecular information is a challenging area of research, which is essential to develop precision medicine. In this paper, we develop translational models to identify major actionable proteins that are associated with clinical outcomes, like the survival time of patients. There are considerable statistical and computational challenges due to the large dimension of the problems. Furthermore, data are available for different tumor types; hence data integration for various tumors is desirable. Having censored survival outcomes escalates one more level of complexity in the inferential procedure. We develop Bayesian hierarchical survival models, which accommodate all the challenges mentioned here. We use the hierarchical Bayesian accelerated failure time model for survival regression. Furthermore, we assume sparse horseshoe prior distribution for the regression coefficients to identify the major proteomic drivers. We borrow strength across tumor groups by introducing a correlation structure among the prior distributions. The proposed methods have been used to analyze data from the recently curated ‚ÄúThe Cancer Proteome Atlas‚ÄĚ (TCPA), which contains reverse‚Äźphase protein arrays‚Äďbased high‚Äźquality protein expression data as well as detailed clinical annotation, including survival times. Our simulation and the TCPA data analysis illustrate the efficacy of the proposed integrative model, which links different tumors with the correlated prior structures.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154486/1/biom13132_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154486/2/biom13132.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154486/3/biom13132-sup-0003-supmat.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154486/4/biom13132-sup-0002-supplementary-v6-22Jul2019.pd

    Hepatic Ultrasonography Compared with Computed Tomography and Magnetic Resonance Imaging at Diagnosis of Metastatic Uveal Melanoma

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    Purpose To evaluate the consistency of hepatic ultrasonography (US) with staging computed tomography (CT) and magnetic resonance imaging (MRI), to analyze why US was inconsistent with CT/MRI, and to compare CT/MRI. DESIGN Reliability analysis. METHODS Two hundred fifteen patients whose primary uveal melanoma was managed in the Helsinki University Hospital and who were diagnosed with hepatic metastases by US within 60 days of staging CT/MRI from January 1999 to December 2016, were included. Patients attended a real-life follow-up schedule including hepatic US, liver function tests (LFT), and a confirmatory CT/MRI. We evaluated the consistency of US with staging CT/MRI regarding the presence and number of metastases. RESULTS The enrolled patients underwent 215 US, 167 CT, and 69 MRI examinations, and 67% of them had biopsy-confirmed metastases. Screening was regular for 98% of the patients, and 66% were asymptomatic. US was fully consistent with CT/MRI in detecting metastases in 113 (53%) patients, in 63 (29%) CT/MRI showed more metastases, and in 16 (7%) less metastases than US. CT/MRI was inconsistent with US in 23 (11%) patients. The sensitivity of US in detecting metastases was 96% (95% confidence interval, 92-98). US failed to suggest metastases in 10 patients. LFT were abnormal in six of them, and a newly-detected hepatic lesion was present by US in four. CONCLUSIONS Hepatic US is a sensitive screening modality in detecting metastases in patients with primary uveal melanoma, if combined with LFT and in case of any new detected lesion, a confirmatory MRI.Peer reviewe
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