148 research outputs found

    Prevalence of Exposure to Complex Trauma and Community Violence and Their Associations With Internalizing and Externalizing Symptoms

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    Studies about trauma often tend to focus on abuse and neglect. However important, these studies may neglect the importance of the broader community context that is often associated with trauma, and complex trauma (CT) in particular. This study aimed to investigate the effects of CT (defined in terms of experiencing abuse and/or neglect occurring in the context of relationships with caregivers), and of broader environmental adversity (i.e., exposure to community violence), in a sample of adolescents ( N = 218) from a severely disadvantaged district of Lima, Peru. The study had two aims: (a) to assess the prevalence of CT and its associations with internalizing and externalizing symptoms in these adolescents and (b) to investigate the associations between community violence and both internalizing and externalizing symptoms over and above the effects of CT. In total, 39.4% of the adolescents reported at least one type of moderate to severe trauma. There was a clear association between CT and both internalizing and externalizing symptoms. Ordinal logistic regressions showed that children who were exposed to one or more traumatic experiences were more likely to score within a higher range of internalizing and externalizing symptoms than children with no history of trauma. Finally, exposure to community violence was an important predictor of symptomatology beyond the effects of CT

    Silicon photomultiplier arrays - a novel photon detector for a high resolution tracker produced at FBK-irst, Italy

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    A silicon photomultiplier (SiPM) array has been developed at FBK-irst having 32 channels and a dimension of 8.0 x 1.1 mm^2. Each 250 um wide channel is subdivided into 5 x 22 rectangularly arranged pixels. These sensors are developed to read out a modular high resolution scintillating fiber tracker. Key properties like breakdown voltage, gain and photon detection efficiency (PDE) are found to be homogeneous over all 32 channels of an SiPM array. This could make scintillating fiber trackers with SiPM array readout a promising alternative to available tracker technologies, if noise properties and the PDE are improved

    Optimization and matrix constructions for classification of data

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    Max-plus algebras and more general semirings have many useful applications and have been actively investigated. On the other hand, structural matrix rings are also well known and have been considered by many authors. The main theorem of this article completely describes all optimal ideals in the more general structural matrix semirings. Originally, our investigation of these ideals was motivated by applications in data mining for the design of centroid-based classification systems, as well as for the design of multiple classification systems combining several individual classifiers

    A Scintillating Fiber Tracker With SiPM Readout

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    We present a prototype for the first tracking detector consisting of 250 micron thin scintillating fibers and silicon photomultiplier (SiPM) arrays. The detector has a modular design, each module consists of a mechanical support structure of 10mm Rohacell foam between two 100 micron thin carbon fiber skins. Five layers of scintillating fibers are glued to both top and bottom of the support structure. SiPM arrays with a channel pitch of 250 micron are placed in front of the fibers. We show the results of the first module prototype using multiclad fibers of types Bicron BCF-20 and Kuraray SCSF-81M that were read out by novel 32-channel SiPM arrays from FBK-irst/INFN Perugia as well as 32-channel SiPM arrays produced by Hamamatsu. A spatial resolution of 88 micron +/- 6 micron at an average yield of 10 detected photons per minimal ionizig particle has been achieved.Comment: 5 pages, 7 figures, submitted as proceedings to the 11th Topical Seminar on Innovative Particle and Radiation Detectors (IPRD08

    On wealth and the diversity of friendships: high social class people around the world have fewer international friends

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    Having international social ties carries many potential advantages, including access to novel ideas and greater commercial opportunities. Yet little is known about who forms more international friendships. Here, we propose social class plays a key role in determining people's internationalism. We conducted two studies to test whether social class is related positively to internationalism (the building social class hypothesis) or negatively to internationalism (the restricting social class hypothesis). In Study 1, we found that among individuals in the United States, social class was negatively related to percentage of friends on Facebook that are outside the United States. In Study 2, we extended these findings to the global level by analyzing country-level data on Facebook friends formed in 2011 (nearly 50 billion friendships) across 187 countries. We found that people from higher social class countries (as indexed by GDP per capita) had lower levels of internationalism—that is, they made more friendships domestically than abroad

    Validation of the quality of relationships inventory in a peruvian sample of adolescents and associations to peer attachment

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    Research concerning adolescent peer relations and peer attachment is scarce, and more so in Spanish-speaking populations. The aims of this study were twofold: (a) to adapt the Quality of Relationships Inventory (QRI) to Spanish and (b) to assess its psychometric properties in the context of peer relations in a sample of N = 269 Peruvian adolescents. Internal consistency was adequate. The factor structure of the instrument was assessed by means of confirmatory factor analysis (CFA) and multidimensional scaling (MDS). Convergent validity was explored by analyzing the associations between the QRI subscales and the peer subscales of the Inventory of Parent and Peer Attachment (correlations ranged from r = .37 to r = .61) and discriminant validity by exploring the associations between the QRI subscales and both internalizing and externalizing symptoms (correlations ranged from r = .27 to r = .35). Results showed that the QRI on its Spanish version is a reliable tool for the assessment of the quality of peer relationships within a Peruvian context when taking some considerations into account regarding the conflict scale

    PEBS - Positron Electron Balloon Spectrometer

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    The best measurement of the cosmic ray positron flux available today was performed by the HEAT balloon experiment more than 10 years ago. Given the limitations in weight and power consumption for balloon experiments, a novel approach was needed to design a detector which could increase the existing data by more than a factor of 100. Using silicon photomultipliers for the readout of a scintillating fiber tracker and of an imaging electromagnetic calorimeter, the PEBS detector features a large geometrical acceptance of 2500 cm^2 sr for positrons, a total weight of 1500 kg and a power consumption of 600 W. The experiment is intended to measure cosmic ray particle spectra for a period of up to 20 days at an altitude of 40 km circulating the North or South Pole. A full Geant 4 simulation of the detector concept has been developed and key elements have been verified in a testbeam in October 2006 at CERN.Comment: 5 pages, 7 figures, submitted to Proceedings of the 11th Vienna Conference on Instrumentatio

    Clinical, Serological, and Molecular Observations from a Case Series Study during the Asian Lineage Zika Virus Outbreak in Grenada during 2016

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    This paper describes the spatial and temporal distribution of cases, demographic characteristics of patients, and clinical manifestations of Zika virus (ZIKV) during the 2016 outbreak in Grenada. The first reported case was recorded in St. Andrew Parish in April, and the last reported case was seen in November, with peak transmission occurring in the last week of June, based on test results. Data were collected from a total of 514 patients, of whom 207 (40%) tested positive for ZIKV. No evidence was found that testing positive for ZIKV infection was related to age, gender, or pregnancy status. Clinical presentation with rash (OR = 2.4, 95% CI = 1.5 to 3.7) or with lymphadenopathy (OR = 1.7, 95% CI = 1.0 to 2.9) were the only reported symptoms consistent with testing positive for ZIKV infection. During the Zika outbreak, the infection rate was 20 clinical cases per 10,000 in the population compared to 41 cases per 10,000 during the chikungunya outbreak in Grenada in 2014 and 17 cases per 10,000 during the dengue outbreak in 2001-2002. Even though the country has employed vector control programs, with no apparent decrease in infection rates, it appears that new abatement approaches are needed to minimize morbidity in future arbovirus outbreaks
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