11,944 research outputs found
Eco-friendly gas mixtures for Resistive Plate Chambers based on Tetrafluoropropene and Helium
Due to the recent restrictions deriving from the application of the Kyoto
protocol, the main components of the gas mixtures presently used in the
Resistive Plate Chambers systems of the LHC experiments will be most probably
phased out of production in the coming years. Identifying possible replacements
with the adequate characteristics requires an intense R&D, which was recently
started, also in collaborations across the various experiments. Possible
candidates have been proposed and are thoroughly investigated. Some tests on
one of the most promising candidate - HFO-1234ze, an allotropic form of
tetrafluoropropane- have already been reported. Here an innovative approach,
based on the use of Helium, to solve the problems related to the too elevate
operating voltage of HFO-1234ze based gas mixtures, is discussed and the
relative first results are shown.Comment: 9 pages, 6 figures, 1 tabl
Modified POF Sensor for Gaseous Hydrogen Fluoride Monitoring in the Presence of Ionizing Radiations
This paper describes the development of a sensor designed to detect low concentrations of hydrogen fluoride (HF) in gas mixtures. The sensor employs a plastic optical fiber (POF) covered with a thin layer of glass- like material. HF attacks the glass and alters the fiber transmission capability so that the detection simply requires a LED and a photodiode. The coated POF is obtained by means of low-pressure plasma-enhanced chemical vapor deposition that allows the glass-like film to be deposited at low temperature without damaging the fiber core. The developed sensor will be installed in the recirculation gas system of the resistive plate chamber muon detector of the Compact Muon Solenoid experiment at the Large Hadron Collider accelerator of the European Organization for Nuclear Research (CERN
Fiber Bragg Grating sensors for deformation monitoring of GEM foils in HEP detectors
Fiber Bragg Grating (FBG) sensors have been so far mainly used in high energy
physics (HEP) as high precision positioning and re-positioning sensors and as
low cost, easy to mount, radiation hard and low space- consuming temperature
and humidity devices. FBGs are also commonly used for very precise strain
measurements. In this work we present a novel use of FBGs as flatness and
mechanical tensioning sensors applied to the wide Gas Electron Multiplier (GEM)
foils of the GE1/1 chambers of the Compact Muon Solenoid (CMS) experiment at
Large Hadron Collider (LHC) of CERN. A network of FBG sensors has been used to
determine the optimal mechanical tension applied and to characterize the
mechanical stress applied to the foils. The preliminary results of the test
performed on a full size GE1/1 final prototype and possible future developments
will be discussed.Comment: Four pages, seven figures. Presented by Michele Caponero at IWASI
2015, Gallipoli (Italy
From research to clinical practice: a systematic review of the implementation of psychological interventions for chronic headache in adults
Background: Psychological interventions have been proved to be effective in chronic headache (CH) in adults. Nevertheless, no data exist about their actual implementation into standard clinical settings. We aimed at critically depicting the current application of psychological interventions for CH into standard care exploring barriers and facilitators to their implementation. Secondarily, main outcomes of the most recent psychological interventions for CH in adults have been summarized. Methods: We conducted a systematic review through PubMed and PsycINFO in the time range 2008-2018. A quality analysis according to the QATSDD tool and a narrative synthesis were performed. We integrated results by: contacting the corresponding author of each paper; exploring the website of the clinical centers cited in the papers. Results: Of the 938 identified studies, 28 papers were selected, whose quality largely varied with an average %QATSDD quality score of 64.88%. Interventions included CBT (42.85%), multi-disciplinary treatments (22.43%), relaxation training (17.86%), biofeedback (7.14%), or other interventions (10.72%). Treatments duration (1 day-9 months) and intensity varied, with a prevalence of individual-basis implementation. The majority of the studies focused on all primary headaches; 4 studies focused on medication-overuse headache. Most of the studies suggest interventions as effective, with the reduction in frequency of attacks as the most reported outcome (46.43%). Studies were distributed in different countries, with a prevalent and balanced distribution in USA and Europe. Ten researches (35.71%) were performed in academic contexts, 11 (39.28%) in clinical settings, 7 (25%) in pain/headache centres. Interventions providers were professionals with certified experience. Most of the studies were funded with private or public funding. Two contacted authors answered to our e-mail survey, with only one intervention implemented in the routine clinical practice. Only in three out of the 16 available websites a reference to the implementation into the clinical setting was reported. Conclusion: Analysis of contextual barriers/facilitators and cost-effectiveness should be included in future studies, and contents regarding dissemination/implementation of interventions should be incorporated in the professional training of clinical scientists. This can help in filling the gap between the existing published research and treatments actually offered to people with CH
Intrinsic point defects in silica for fiber optics applications
Due to its unique properties, amorphous silicon dioxide (a-SiO2 ) or silica is a key material in many technological fields, such as high-power laser systems, telecommunications, and fiber optics. In recent years, major efforts have been made in the development of highly transparent glasses, able to resist ionizing and non-ionizing radiation. However the widespread application of many silica-based technologies, particularly silica optical fibers, is still limited by the radiation-induced formation of point defects, which decrease their durability and transmission efficiency. Although this aspect has been widely investigated, the optical properties of certain defects and the correlation between their formation dynamics and the structure of the pristine glass remains an open issue. For this reason, it is of paramount importance to gain a deeper understanding of the structureâreactivity relationship in a-SiO2 for the prediction of the optical properties of a glass based on its manufacturing parameters, and the realization of more efficient devices. To this end, we here report on the state of the most important intrinsic point defects in pure silica, with a particular emphasis on their main spectroscopic features, their atomic structure, and the effects of their presence on the transmission properties of optical fibers
Pain and self-preservation in autonomous robots: From neurobiological models to psychiatric disease
The use of biologically realistic (brain-like) control systems in autonomous robots offers two potential benefits. For neuroscience, it may provide important insights into normal and abnormal control and decision-making in the brain, by testing whether the computational learning and decision rules proposed on the basis of simple laboratory experiments lead to effective and coherent behaviour in complex environments. For robotics, it may offer new insights into control system designs, for example in the context of threat avoidance and self-preservation. In the brain, learning and decision-making for rewards and punishments (such as pain) are thought to involve integrated systems for innate (Pavlovian) responding, habit-based learning, and goal-directed learning, and these systems have been shown to be well-described by RL models. Here, we simulated this 3-system control hierarchy (in which the innate system is derived from an evolutionary learning model), and show that it reliably achieves successful performance in a dynamic predator-avoidance task. Furthermore, we show situations in which a 3-system architecture provides clear advantages over single or dual system architectures. Finally, we show that simulating a computational model of obsessive compulsive disorder, an example of a disease thought to involve a specific deficit in the integration of habit-based and goal-directed systems, can reproduce the results of human clinical experiments. The results illustrate how robotics can provide a valuable platform to test the validity and utility of computational models of human behaviour, in both health and disease. They also illustrate how bio-inspired control systems might usefully inform self-preservative behaviour in autonomous robots, both in normal and malfunctioning situations
The complex relation between executive functions and language in preschoolers with developmental language disorders
Backgrounds: The relationship between linguistic difficulties and cognitive impairments in children with developmental language disorders (DLDs) is receiving growing interest in international research. Executive functions (EF) appear to be weak in these children. The current investigation aims at exploring the relationship between difficulties in two components of EF (i.e., updating and inhibition) and the linguistic and narrative skills of 16 DLD preschoolers matched with 24 typically developing peers. Methods: Updating skills were tested by administering the forward and backward digit recall subtests of the Wechsler Scales, while children\u2019s inhibition abilities were assessed by completion of Developmental Neuropsychological Assessment (NEPSY-II) inhibition tasks. Information on the linguistic skills of the participants was collected through a set of subtests included in the Batteria per la Valutazione del Linguaggio in bambini dai 4 ai 12 anni (Batteria per la Valutazione del Linguaggio; BVL_4-12), assessing articulatory and phonological discrimination skills, lexical production/comprehension, grammatical production/comprehension, and narrative production skills. Results: Findings revealed that DLD children performed significantly lower than their peers on both updating and inhibitory tasks. Linguistic difficulties were found in the DLD group on articulatory/phonological skills, grammatical production/comprehension, and lexical informativeness on narrative production. Measures of EF correlated with linguistic and narrative measures. Conclusion: The current study confirms a significant association between DLD\u2019s performances on EF and displayed linguistic skills, suggesting the need to include the assessment of executive functions to target early intervention rehabilitation programs for children with DLDs
Cms gem detector material study for the hl-lhc
A study on the Gaseous Electron Multiplier (GEM) foil material is performed to determine the moisture diffusion rate, moisture saturation level and the effects on its mechanical properties. The study is focused on the foil contact with ambient air and moisture to determine the value of the diffusion coefficient of water in the foil material. The presence of water inside the detector foil can determine the changes in its mechanical and electrical properties. A simulated model is developed with COMSOL Multiphysics v. 4.3 [1] by taking into account the real GEM foil (hole dimensions, shapes and material), which describes the adsorption of water. This work describes the model, its experimental verification, the water diffusion within the entire sheet geometry of the GEM foil, thus gaining concentration profiles and the time required to saturate the system and the effects on the mechanical properties
Influences of postharvest storage and processing techniques on antioxidant and nutraceutical properties of rubus idaeus l.: A mini-review
The growth of agricultural mechanization has promoted an increase in raspberry production, and for this reason, the best postharvest storage and processing techniques capable of maintaining the health beneficial properties of these perishable berry fruits have been widely studied. Indeed, raspberries are a rich source of bioactive chemical compounds (e.g., ellagitannins, anthocyanins, and ascorbic acid), but these can be altered by postharvest storage and processing techniques before consumption. Although there are clear differences in storage times and techniques, the content of bioactive chemical compounds is relatively stable with some minor changes in ascorbic acid or anthocyanin content during cold (5âŠC) or frozen storage. In the literature, processing techniques such as juicing or drying have negatively affected the content of bioactive chemical compounds. Among drying techniques, hot air (oven) drying is the process that alters the content of bioactive chemical compounds the most. For this reason, new drying technologies such as microwave and heat pumps have been developed. These novel techniques are more successful in retaining bioactive chemical compounds with respect to conventional hot air drying. This mini-review surveys recent literature concerning the effects of postharvest storage and processing techniques on raspberry bioactive chemical compound content
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