A Meta‐analysis for Exploring the Diverse Causes and Effects of Stress in Teachers

This study provides a correlational meta‐analysis of 65 independently written or published studies on teacher stress between 1998 and 2003. We measured the relationships between teacher stress and numerous other constructs including coping, burnout, emotional responses, personality mediators, personal support, environmental structure, and background characteristics. A theoretical‐empirical model of construct relationships investigated across studies was developed and n = 2,527 correlational effect sizes were used to estimate the empirical relationships between the operationalized theoretical constructs. Results showed that the strongest association of teacher stressors exists with negatively oriented emotional responses confirming the central role of teachers’ coping mechanisms, personality mediators, and burnout potential according to our model of the stress cycle. Key words: stress, coping, teacher burn‐out, teacher emotional response Cette recherche fournit une méta‐analyse corrélationnelle de 65 études, rédigées ou publiées entre 1998 et 2003, sur le stress chez les enseignants. Les auteurs ont mesuré les relations entre le stress des enseignants et de nombreux autres construits, dont l’adaptation au stress, l’épuisement professionnel, les réactions émotionnelles, les personality mediators, le soutien personnel, la structure du milieu et les antécédents. Un modèle théorico‐empirique des relations entre les construits a été élaboré et des valeurs d’effets corrélationnels de n = 2527 ont été utilisées pour déterminer les relations empiriques entre les construits théoriques opérationalisés. Les résultats démontrent que, pour les facteurs de stress chez les enseignants, l’association la plus importante se trouve du côté des réactions émotionnelles négatives, ce qui confirme le rôle clé des mécanismes d’adaptation au stress des enseignants, des personality mediators et du potentiel d’épuisement professionnel selon le modèle du cycle du stress qui a été utilisé. Mots clés : stress, adaptation au stress, méta‐analyse, enseignants.

Energy efficiency of mmWave massive MIMO precoding with low-resolution DACs

With the congestion of the sub-6 GHz spectrum, the interest in massive multiple-input multiple-output (MIMO) systems operating on millimeter wave spectrum grows. In order to reduce the power consumption of such massive MIMO systems, hybrid analog/digital transceivers and application of low-resolution digital-to-analog/analog-to-digital converters have been recently proposed. In this work, we investigate the energy efficiency of quantized hybrid transmitters equipped with a fully/partially-connected phase-shifting network composed of active/passive phase-shifters and compare it to that of quantized digital precoders. We introduce a quantized single-user MIMO system model based on an additive quantization noise approximation considering realistic power consumption and loss models to evaluate the spectral and energy efficiencies of the transmit precoding methods. Simulation results show that partially-connected hybrid precoders can be more energy-efficient compared to digital precoders, while fully-connected hybrid precoders exhibit poor energy efficiency in general. Also, the topology of phase-shifting components offers an energy-spectral efficiency trade-off: active phase-shifters provide higher data rates, while passive phase-shifters maintain better energy efficiency.Comment: Published in IEEE Journal of Selected Topics in Signal Processin

112.social: Design and Evaluation of a Mobile Crisis App for Bidirectional Communication between Emergency Services and Citizens

Emergencies threaten human lives and overall societal continuity, whether or not the crises and disasters are induced by nature, such as earthquakes, floods and hurricanes, or by human beings, such as accidents, terror attacks and uprisings. In such situations, not only do citizens demand information about the damage and safe behaviour, but emergency services also require high quality information to improve situational awareness. For this purpose, there are currently two kinds of apps available: General-purpose apps, such as Facebook Safety Check or Twitter Alerts, already integrate safety features. Specific crisis apps, such as KATWARN in Germany or FEMA in the US, provide information on how to behave before, during and after emergencies, and capabilities for reporting incidents or receiving disaster warnings. In this paper, we analyse authorities’ and citizens’ information demands and features of crisis apps. Moreover, we present the concept, implementation and evaluation of a crisis app for incident reporting and bidirectional communication between authorities and citizens. Using the app, citizens may (1) report incidents by providing a category, description, location and multimedia files and (2) receive broadcasts and responses from authorities. Finally, we outline features, requirements and contextual factors for incident reporting and bidirectional communication via mobile app

Which Model is Best? Robustness Properties to Justify Model Choice Among Unidimensional IRT Models under Item Parameter Drift

This article extends recent research on item parameter drift by investigating the robustness properties of basic unidimensional IRT models. Specifically, the article explores whether it is possible to advocate the consistent choice of one model over another based on its robustness properties under drift. On the one hand, it is shown that the biases that are introduced due to drift are minor for most practically relevant circumstances across all models. On the other hand, it is shown that the mathematical structure of the biases is theoretically complex so that globally superior performance of one model over another is observed only under restrictive side conditions

112.SOCIAL: Design and Evaluation of a Mobile Crisis App for Bidirectional Communication between Emergency Services and Citizen

Emergencies threaten human lives and overall societal continuity, whether or not the crises and disasters are induced by nature, such as earthquakes, floods and hurricanes, or by human beings, such as accidents, terror attacks and uprisings. In such situations, not only do citizens demand information about the damage and safe behaviour, but emergency services also require high quality information to improve situational awareness. For this purpose, there are currently two kinds of apps available: General-purpose apps, such as Facebook Safety Check or Twitter Alerts, already integrate safety features. Specific crisis apps, such as KATWARN in Germany or FEMA in the US, provide information on how to behave before, during and after emergencies, and capabilities for reporting incidents or receiving disaster warnings. In this paper, we analyse authorities’ and citizens’ information demands and features of crisis apps. Moreover, we present the concept, implementation and evaluation of a crisis app for incident reporting and bidirectional communication between authorities and citizens. Using the app, citizens may (1) report incidents by providing a category, description, location and multimedia files and (2) receive broadcasts and responses from authorities. Finally, we outline features, requirements and contextual factors for incident reporting and bidirectional communication via mobile app

Detection of genes influencing economic traits in three French dairy cattle breeds

A project of QTL detection was carried out in the French Holstein, Normande, and Montbéliarde dairy cattle breeds. This granddaughter design included 1 548 artificial insemination bulls distributed in 14 sire families and evaluated after a progeny-test for 24 traits (production, milk composition, persistency, type, fertility, mastitis resistance, and milking ease). These bulls were also genotyped for 169 genetic markers, mostly microsatellites. The QTL were analysed by within-sire linear regression of daughter yield deviations or deregressed proofs on the probability that the son receives one or the other paternal QTL allele, given the marker information. QTL were detected for all traits, including those with a low heritability. One hundred and twenty QTL with a chromosome-wise significance lower than 3% were tabulated. This threshold corresponded to a 15% false discovery rate. Amongst them, 32 were genome-wise significant. Estimates of their contribution to genetic variance ranged from 6 to 40%. Most substitution effects ranged from 0.6 to 1.0 genetic standard deviation. For a given QTL, only 1 to 5 families out of 14 were informative. The confidence intervals of the QTL locations were large and always greater than 20 cM. This experiment confirmed several already published QTL but most of them were original, particularly for non-production traits