4,773 research outputs found

    The TOTEM Experiment at the LHC

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    The TOTEM experiment at the LHC is dedicated to the measurement of the total pp cross section and to the study of elastic scattering and of diffractive dissociation processes. TOTEM is here presented with a general overview on the main features of its experimental apparatus and of its physics programme.Comment: Proceedings of XLIIIth Rencontres de Moriond - QCD session, La Thuile (Italy), March 14th - 21st, 200

    A triple-GEM telescope for the TOTEM experiment

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    The TOTEM experiment at LHC has chosen the triple Gas Electron Multiplier (GEM) technology for its T2 telescope which will provide charged track reconstruction in the rapidity range 5.3<|eta|<6.5 and a fully inclusive trigger for diffractive events. GEMs are gas-filled detectors that have the advantageous decoupling of the charge amplification structure from the charge collection and readout structure. Furthermore, they combine good spatial resolution with very high rate capability and a good resistance to radiation. Results from a detailed T2 GEM simulation and from laboratory tests on a final design detector performed at CERN are presented.Comment: To appear in the proceedings of 10th Topical Seminar on Innovative Particle and Radiation Detectors (IPRD06), Siena, Italy, October 1-5 200

    The performance of green communication across social media: Evidence from large-scale retail industry in Italy

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    Social media have surged prominently as communication channels for corporate social responsibility. However, little is still known about the performance of green versus non-green communication across different social media. We contribute by examining whether the presence of green features in social media communication exerts a beneficial effect on consumer response in terms of likes, comments, and shares. We also investigate how this effect hinges upon the social media platform where the content is posted as well as the richness of the format (text, photos, videos) utilized for the diffusion. To our scopes, we use an ad hoc dataset of posts of two major large-scale retailers in Italy across three major social media, namely Facebook, Instagram, and Twitter. Our results show that, while green content generally stimulates larger response than non-green content, its effect varies across social media, with the highest effect being observed on Instagram (at least for likes) and the lowest on Twitter (at least for comments). Moreover, the extent to which the positive effect of green content increases as media richness increases (i.e., moving from only text to text plus photo, and then to text plus video) is also contingent upon the social media platform. On Facebook, the moderation of media richness is positive and significant, while being insignificant on Instagram. On Twitter, the moderation is even nonmonotonic in the sense that the highest (positive) effect of green content tends to be obtained for either low or high media richness. Our findings offer remarkable implications for firms engaging in environmental sustainability

    A Comprehensive Overview of the Temperature-Dependent Modeling of the High-Power GaN HEMT Technology Using mm-Wave Scattering Parameter Measurements (Invited Paper)

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    The gallium-nitride (GaN) high electron-mobility transistor (HEMT) technology has emerged as an attractive candidate for high-frequency, high-power, and high-temperature applications due to the unique physical characteristics of the GaN material. Over the years, much effort has been spent on measurement-based modeling since accurate models are essential for allowing the use of this advanced transistor technology at its best. The present analysis is focused on the modeling of the scattering (S-) parameter measurements for a 0.25 μm GaN HEMT on silicon carbide (SiC) substrate at extreme operating conditions: a large gate width (i.e., the transistor is based on an interdigitated layout consisting of ten fingers, each with a length of 150 μm, resulting in a total gate periphery of 1.5 mm), a high ambient temperature (i.e., from 35 °C up to 200 °C with a step of 55 °C), a high dissipated power (i.e., 5.1 W at 35 °C), and a high frequency in the millimeter-wave range (i.e., from 200 MHz up to 65 GHz with a step of 200 MHz). Three different modeling approaches are investigated: the equivalent-circuit model, artificial neural networks (ANNs), and gated recurrent units (GRUs). As is shown, each modeling approach has its pros and cons that need to be considered, depending on the target performance and their specifications. This implies that an appropriate selection of the transistor modeling approach should be based on discerning and prioritizing the key features that are indeed the most important for a given application

    The role of parental involvement in youth sport experience: perceived and desired behavior by male soccer players

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    Parents play a key role in the youth sports educational experience. They are responsible for the introduction of their children to physical or sporting education and their involvement has been associated with sport participation in early stages. The aims of this cross-sectional study were, first, to assess the perceived and desired parental involvement by children and, secondly, to exam-ine their satisfaction or dissatisfaction with any specific behavior. 80 male soccer players filled the Parental Involvement in Sport Questionnaire (PISQ) before or after a training session in presence of a coach. PISQ results revealed excessive active involvement and pressure, insufficient praise and understanding and satisfactory directive behavior from children’s parents. Our findings suggest that excessive parental involvement can cause pressure on children who would prefer parental participation characterized by praise and understanding. A balance between a supporting involvement without putting too much pressure is needed by the parents. To prevent burnout and dropout and to facilitate future practice, parents should be counseled (possibly by a sport educator) on how to positively support their children concerning their sport experience

    CdO-based nanostructures as novel CO2 gas sensors

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    Crystalline Cd(OH)2/CdCO3 nanowires, having lengths in the range from 0.3 up to several microns and 5–30 nm in diameter, were synthesized by a microwave-assisted wet chemical route and used as a precursor to obtain CdO nanostructures after a suitable thermal treatment in air. The morphology and microstructure of the as-synthesized and annealed materials have been investigated by scanning electron microscopy, transmission electron microscopy, x-ray diffraction and thermogravimetry–differential scanning calorimetry. The change in morphology and electrical properties with temperature has revealed a wire-to-rod transformation along with a decreases of electrical resistance. Annealed samples were printed on a ceramic substrate with interdigitated contacts to fabricate resistive solid state sensors. Gas sensing properties were explored by monitoring CO2 in synthetic air in the concentration range 0.2–5 v/v% (2000–50 000 ppm). The effect of annealing temperature, working temperature and CO2 concentration on sensing properties (sensitivity, response/recovery time and stability) were investigated. The results obtained demonstrate that CdO-based thick films have good potential as novel CO2 sensors for practical applications

    Flatfoot in children: anatomy of decision making

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    Concern about a child’s foot posture is a common reason for frequent consultations for an array of health care professionals; sports medicine specialists are often the first to recognize and advise on foot pathology. In the decision making process, it is essential to distinguish between the different types of flatfoot deformity: paediatric or adult, congenital or acquired, flexible or rigid. Although flatfoot in children is a common finding, evidence for the techniques of the reliable and reproducible assessment of the foot posture is scant. This general review presents the factors involved in the forming and supporting of the foot arches, discusses the protocols useful in the evaluation of the foot posture, and indicates how to differentiate between flatfoot cases needing treatment and cases that need only reassurance
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