2,074 research outputs found

    Risky,early, controversial. Puberty in medical discourses

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    This article comes within the compass of a research program (entitled CorAge. Bodily Experiences and AgePassages among 9e13 year-olds (ANR-09-ENFT-017) conducted between 2009 and 2013 about the emergence of a \u201cnew\u201d age in life -\u201cpreadolescence\u201d- as instanced in France (Alsace, Lorraine) and Italy (Venetia). The impressive amount of references to \u201cearly puberty\u201d and \u201cprecocious puberty\u201d, in a context of feeling of a premature end of childhood, led us to make an in-depth study of this issue: \ufb01rst, through an analysis of international and French and Italian medical journals; second, through interviews with health professionals. Following the thesis of Foucault, we assume that the discourses on puberty timing participate of classi\ufb01cations of the child body drenched with moral representations of childhood, especially on gender and age issue. Our results: the question of whether a secular trend in puberty timing even exists continues to be debated between American and European scientists. Second, the terms \u201cpuberty\u201d, \u201cprecocious puberty\u201d, \u201cearly puberty\u201d have been used to indicate a variety of puberty markers, increasing confusion. A controversy has focused on early breast development in girls, because this attribute is questioning the order of ages and gender. Moreover, psychosocial factors presented as accelerating early puberty, do not demonstrate the relation between earliness and risk behavior. The literature, as it is moved by the female precocity, creates a medical category to objectify the complex and \ufb02exible process of puberty and invent female child precocity. These differences between American and European scholars and the interviews with French and Italian health professional show a gap between the international literature and practitioners, clinicians and nurses who regularly work with children: they neither \ufb01nd pubertal advancement, nor increase of \u201ctrue precocious puberty\u201d, although they share concerns about premature feminization of girls (France) or environmental toxicity (Italy) on children

    Experimental and numerical analysis of supersonic blade profiles developed for highly loaded impulse type steam turbine stages

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    The paper describes the results of a numerical and experimental research program addressing the aerodynamic investigation on the performance of blade profiles specifically developed for application in highly loaded impulse type turbine stages. The industrial requirements driving toward the adoption of highly loaded stage solutions are presented, along with an estimation of the profiles operating parameters. Two stator vanes and one rotor blade profile have been developed and extensively tested by means of flow field measurements and schlieren visualization in a transonic blow-down wind tunnel for linear cascades. Experimental results for the relevant operating conditions are presented, providing validation data for the CFD model used for blade design and evidencing that the main goals of the design optimization procedure have been achieved

    Search for Intermediate Mass Magnetic Monopoles and Nuclearites with the SLIM experiment

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    SLIM is a large area experiment (440 m2) installed at the Chacaltaya cosmic ray laboratory since 2001, and about 100 m2 at Koksil, Himalaya, since 2003. It is devoted to the search for intermediate mass magnetic monopoles (107-1013 GeV/c2) and nuclearites in the cosmic radiation using stacks of CR39 and Makrofol nuclear track detectors. In four years of operation it will reach a sensitivity to a flux of about 10-15 cm-2 s-1 sr-1. We present the results of the calibration of CR39 and Makrofol and the analysis of a first sample of the exposed detector.Comment: Presented at the 22nd ICNTS, Barcelona 200

    Experimental Observation of Non-Ideal Nozzle Flow of Siloxane Vapor MDM

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    The first experimental results from the Test-Rig for Organic Vapors (TROVA) at Politecnico di Milano are reported. The facility implements an Organic Rankine Cycle (ORC) where the expansion process takes place within a straight axis convergent-divergent nozzle, which is the simplest geometry representative of an ORC turbine blade passage. In order to reduce the required input thermal power, a batch operating mode was selected for the plant. Experimental runs with air allowed to verify the throttling valve operation and the measurement techniques, which include total pressure and temperature measurements in the settling chamber, static pressure measurements along the nozzle axis. A double-passage Schlieren technique is used to visualize the flow field in the nozzle throat and divergent section and to determine the position of shock waves within the flow field. The first experimental observation of non-ideal nozzle flows are presented for the expansion of siloxane fluid MDM (C8H24O2Si3, octamethyltrisiloxane) for vapor expansion in the close proximity of the liquid-vapor saturation curve, at relatively low pressure of operation. A supersonic flow is attained within the divergent section of the nozzle, as demonstrated by the observation of an oblique shock wave at the throat section, where a 0.1 mm recessed step is located. Schlieren visualizations are limited by the occurrence of condensation along the mirror side of the nozzle. Pressure measurements are compatible with the observed flow field

    Search for strange quark matter and Q-balls with the SLIM experiment

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    We report on the search for Strange Quark Matter (SQM) and charged Q-balls with the SLIM experiment at the Chacaltaya High Altitude Laboratory (5230 m a.s.l.) from 2001 to 2005. The SLIM experiment was a 427 m2^{2} array of Nuclear Track Detectors (NTDs) arranged in modules of 24×2424 \times 24 cm2^{2} area. SLIM NTDs were exposed to the cosmic radiation for 4.22 years after which they were brought back to the Bologna Laboratory where they were etched and analyzed. We estimate the properties and energy losses in matter of nuclearites (large SQM nuggets), strangelets (small charged SQM nuggets) and Q-balls; and discuss their detection with the SLIM experiment. The flux upper limits in the CR of such downgoing particles are at the level of 1.310151.3 10^{-15}/cm2^{2}/s/sr (90% CL).Comment: 4 pages, 7 eps figures. Talk given at the 24th International Conference on Nuclear Tracks in Solids, Bologna, Italy, 1-5 September 200

    Time variations in the deep underground muon flux measured by MACRO

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    More than 30 million of high-energy muons collected with the MACRO detector at the underground Gran Sasso Laboratory have been used to search for flux variations of different natures. Two kinds of studies were carried out: search for periodic variations and for the occurrence of clusters of events. Different analysis methods, including Lomb-Scargle spectral analysis and Scan Test statistics have been applied to the data.Comment: 6 pages, 4 EPS figures. Talk given at the 29th ICRC, Pune, India, 3-10 August 200

    Nuclear Track Detectors for Environmental Studies and Radiation Monitoring

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    Several improvements were made for Nuclear Track Detectors (NTDs) used for environmental studies and for particle searches. A new method was used to determine the bulk etch rate of CR39 and Makrofol NTDs. It is based on the simultaneous measurement of the diameter and of the height of etch-pit cones caused by relativistic heavy ions (158 A GeV Pb(82+) and In(49+) ions) and their fragments. The use of alcohol in the etching solution improves the surface quality of NTDs and it raises their thresholds. The detectors were used for the determination of nuclear fragmentation cross sections of Iron and Silicon ions of 1.0 and 0.41 GeV/nucleon. These measurements are important for the determination of doses in hadron therapy and for doses received by astronauts. The detectors were also used in the search of massive particles in the cosmic radiation, for the determination of the mass spectrum of cosmic rays and for the evaluation of Po(210) alpha decay and of natural radon concentrations.Comment: 7 pages, 5 EPS figures. Presented at the 10th Topical Seminar on Innovative Particle and Radiation Detectors, 1-5 October 2006, Siena, Ital

    Search for spontaneous muon emission from lead nuclei

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    We describe a possible search for muonic radioactivity from lead nuclei using the base elements ("bricks" composed by lead and nuclear emulsion sheets) of the long-baseline OPERA neutrino experiment. We present the results of a Monte Carlo simulation concerning the expected event topologies and estimates of the background events. Using few bricks, we could reach a good sensitivity level.Comment: 12 pages, 4 figure
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