Educational cosmic ray experiments with Geiger counters

Experiments concerning the physics of cosmic rays offer to high-school teachers and students a relatively easy approach to the field of research in high energy physics. The detection of cosmic rays does not necessarily require the use of sophisticated equipment, and various properties of the cosmic radiation can be observed and analysed even by the use of a single Geiger counter. Nevertheless, the variety of such kind of experiments and the results obtained are limited because of the inclusive nature of these measurements. A significant improvement may be obtained when two or more Geiger counters are operated in coincidence. In this paper we discuss the potential of performing educational cosmic ray experiments with Geiger counters. In order to show also the educational value of coincidence techniques, preliminary results of cosmic ray experiments carried out by the use of a simple coincidence circuit are briefly discussed

Educational cosmic-ray experiments with Geiger counters

Experiments concerning the physics of cosmic rays offer to highschool teachers and students a relatively easy approach to the field of research in high-energy physics. The detection of cosmic rays does not necessarily require the use of sophisticated equipment, and various properties of the cosmic radiation can be observed and analysed even by the use of a single Geiger counter. Nevertheless, the variety of such kind of experiments and the results obtained are limited because of the inclusive nature of these measurements. A significant improvement may be obtained when two or more Geiger counters are operated in coincidence. In this paper we discuss the potential of performing educational cosmic-ray experiments with Geiger counters. In order to show also the educational value of coincidence techniques, preliminary results of cosmic-ray experiments carried out by the use of a simple coincidence circuit are briefly discussed

Twin reversed arterial perfusion sequence: current treatment options

Twin reversed arterial perfusion (TRAP) sequence is a specific and severe complication of monochorionic multiple pregnancy, characterized by vascular anastomosis and partial or complete lack of cardiac development in one twin. Despite its rarity, interest in the international literature is rising, and we aimed to review its pathogenesis, prenatal diagnostic features and treatment options. Due to the parasitic hemodynamic dependence of the acardiac twin on the pump twin, the management of these pregnancies aims to maximize the pump twin’s chances of survival. If treatment is needed, the best timing of intervention is still debated, although the latest studies encourage intervention in the first trimester of pregnancy. As for the technique of choice to interrupt the vascular supply to the acardiac twin, ultrasound-guided laser coagulation and radiofrequency ablation of the intrafetal vessels are usually the preferred approaches

Safety performance assessment of food industry facilities using a fuzzy approach

The latest EU policies focus on the issue of food safety with a view to assuring adequate and standard quality levels for the food produced and/or consumed within the EC. To that purpose, the environment where agricultural products are manufactured and processed plays a crucial role in achieving food hygiene. As a consequence, it is of the utmost importance to adopt proper building solutions which meet health and hygiene requirements and to use suitable tools to measure the levels achieved. Similarly, it is necessary to verify and evaluate the level of safety and welfare of the workers in their working environment. The safety of the workers has not only an ethical and social value but also an economic implication, since possible accidents or environmental stressors are the major causes of the lower efficiency and productivity of workers. However, the technical solutions adopted in the manufacturing facilities in order to achieve adequate levels of safety and welfare of the workers are not always consistent with the solutions aimed at achieving adequate levels of food hygiene, even if both of them comply with sectoral rules which are often unconnected with each other. Therefore, it is fundamental to design suitable models of analysis that allow assessing buildings as a whole, taking into account both health and hygiene safety as well as the safety and welfare of workers. Hence, this paper proposes an evaluation model that, based on an established study protocol and on the application of a fuzzy logic procedure, allows evaluating the global safety level of a building. The proposed model allows to obtain a synthetic and global value of the building performance in terms of food hygiene and safety and welfare of the workers as well as to highlight possible weaknesses. Though the model may be applied in either the design or the operational phase of a building, this paper focuses on its application to certain buildings already operational in a specific productive context

Cervical cerclage in twin pregnancies

Purpose To evaluate the outcomes of cervical cerclage (CC) in twin pregnancies. Methods Retrospective analysis of twin pregnancies undergoing CC between January 2001 and December 2009 at our Institution. CC was offered in case of a cervical length measurement B20 mm (ultrasound-indicated CC) or in case of cervical dilatation with membranes at or beyond the external cervical os (physical examination-indicated CC). Cervicovaginal and rectal swabs were obtained preoperatively. Perioperative antibiotics and tocolysis were administered. Results There were 28 cases of ultrasound-indicated and 14 of physical examination-indicated CC. Positive swab cultures were observed in 21 % of cases. The incidence of preterm delivery\34 weeks was 32 % [95 % confidence interval (CI) 16–52 %] and 50 % (95 % CI 23–77 %) in the ultrasound-indicated and physical examination-indicated CC group, respectively. The incidence of premature rupture of membranes \34 weeks was 21 % (95 % CI 8–41 %) and 29 % (95 % CI 8–58 %) in the ultrasoundindicated and physical examination-indicated CC group, respectively. Perinatal survival was 96 % (95 % CI 88–100 %) in the ultrasound-indicated CC group, and 86 % (95 % CI 67–96 %) in the physical examinationindicated CC group.Conclusions We showed a high-risk of preterm delivery in both groups, but with a high overall perinatal survival. Our data stress the importance of re-evaluating the efficacy of CC in twin pregnancies by properly designed clinical trials, particularly if it is physical examination indicated

Improvement of self-sufficiency for an innovative nearly zero energy building by photovoltaic generators

In the present work, a case study of an innovative nearly Zero Energy Building (nZEB) for academic purposes is investigated. In particular, its primary energy vector is electrical, i.e. a Photovoltaic (PV) generator is coupled with storage units and supplies the electrical loads and the thermal demand, which is converted into electrical by heat pumps. The system is designed to maximize the self-sufficiency and minimize the absorption from the grid. Moreover, the nZEB is equipped with sensors that are oriented to smart metering in order to monitor the energy exchange between the rooms of the building. An energy simulation is performed on a yearly basis, evaluating the size of the batteries, to reach the optimal compromise between benefits, in terms of self-sufficiency, and costs

Disaggregated optical network control and orchestration of heterogeneous domains

Network softwarization and disaggregation are two trends that are revolutionizing the network-cloud ecosystem. This paper details possible solutions to control and monitor an infrastructure including an IoT domain, a Cloud domain and a packet-optical network domain

Polyhedral Oligomeric Silsesquioxane Based Catalyst for the Efficient Synthesis of Cyclic Carbonates

In this work, the synthesis of a novel imidazolium-based polyhedral oligomeric silsesquioxane (POSS-mim-Cl) material is presented. The new nanometer-size organosilica based compound was employed for chemical fixation of CO2 into epoxide under homogeneous conditions. The target reaction was represented by the obtention of cyclic carbonates starting from epoxides and CO2. Particularly, styrene oxide was chosen as reference substrate. In addition, different parameters (solvent, temperature, pressure of CO2, and mass of the catalyst) were modified to find the best condition for CO2 conversion. The catalyst POSS-mim-Cl displayed good catalytic performances, the best results being obtained at 40 bar of CO2, 150\ub0C, with 110 mg of catalyst and using isopropanol as co-solvent. It is worth to mention that POSS-mim-Cl displayed better catalytic performance than the corresponding 1-butyl-3-methyl imidazolium chloride. As far as we know this study represents the first use of imidazolium-based POSS as catalysts for the chemical fixation of CO2

Modeling microevolution in a changing environment: The evolving quasispecies and the Diluted Champion Process

Several pathogens use evolvability as a survival strategy against acquired immunity of the host. Despite their high variability in time, some of them exhibit quite low variability within the population at any given time, a somehow paradoxical behavior often called the evolving quasispecies. In this paper we introduce a simplified model of an evolving viral population in which the effects of the acquired immunity of the host are represented by the decrease of the fitness of the corresponding viral strains, depending on the frequency of the strain in the viral population. The model exhibits evolving quasispecies behavior in a certain range of its parameters, ans suggests how punctuated evolution can be induced by a simple feedback mechanism.Comment: 15 pages, 12 figures. Figures redrawn, some additional clarifications in the text. To appear in Journal of Statistical Mechanics: Theory and Experimen