435 research outputs found
The Men's Safer Sex (MenSS) trial: protocol for a pilot randomised controlled trial of an interactive digital intervention to increase condom use in men
Sexually transmitted infections (STI) are a major public health problem. Condoms provide effective protection but there are many barriers to use. Face-to-face health promotion interventions are resource-intensive and show mixed results. Interactive digital interventions may provide a suitable alternative, allowing private access to personally tailored behaviour change support. We have developed an interactive digital intervention (the Men's Safer Sex (MenSS) website) which aims to increase condom use in men. We describe the protocol for a pilot trial to assess the feasibility of a full-scale randomised controlled trial of the MenSS website in addition to usual sexual health clinical care
THE ISOTOPIC SIGNATURE OF THE MINERALIZING FLUID OF THE LAVRION CARBONATE-REPLACEMENT PB-ZN-AG DISTRICT
The Pb-Zn-Ag carbonate-replacement deposits in the Lavrion district are genetically related to a 7- 10 Ma-old granodiorite, felsic dikes and sills. These deposits are hosted in the Upper and Lower marble and schists of the Cyclades Blueschist unit and occur along the major Legraina detachment fault. Carbonate-replacement orebodies occur as âmantosâ and veins, dominated by base metal sulfides and Ag, Bi, Sn, Sb, As, and Pb sulfosalts. Calculated carbon and oxygen isotope compositions of the hydrothermal fluid range from ÎŽ13CCO2 of -13.7 to 0.8 per mil and ÎŽ18OH2O of 4.2 to 27.4 per mil, at 400Âș, 350Âș, 320Âș, 300Âș, 250Âș and 200ÂșC. These isotopic compositions reveal water-torock ratios ranging from 4.8 to 52.6%, which reflect intense interaction of the ore fluid with the host rock in a water-dominated, transitional closed to open hydrothermal system. The range of ÎŽ34SH2S for sulfides in the deposits were from -8.5 to 6.8 per mil, for similar temperatures, whereas for barite-fluorite veins from ÎŽ34SH2S of -43.6 to -16.4 per mil, at 200Âș, 150Âș and 100ÂșC. This range implies that there was contribution from a magmatic sulfur component exsolved from the Plaka pluton, as well as contribution from a metasedimentary component. Based on the isotopic signature of sulfur for barite, the ranges from -6.7 to -7.6, comprising an increase in the fluid influx. Isotopic temperatures based on pyrite-galena and sphalerite-pyrite pairs revealed at least three major events of carbonate-replacement ore deposition, (i) at ~ 360Âș, (ii) 320Âș-280Âșand (iii) 260Âș-200ÂșC
Karakasi mines, Hermione, evolution of a Cyprus-type Cu-Zn deposit, Argolis, Greece
The Hermione Cyprus-type Cu-Zn deposits, Argolis, Greece, are hosted in Miocene ophiolites overlain by terrigenous turbidites with intercalations of limestones and manganiferous iron formations. The ore deposits form irregular lenticular or stratiform ore bodies, and veins. These ore bodies are associated with marginal volcanic activity in an arc-related Miocene palaeocontinent. Late N- to NNE-trending, sinistral, milky quartz-pyrite-calcite veins cut the host ophiolites. Alteration haloes of quartz-calcite, albite-sericite-chlorite, and chalcedony-epidote-clay minerals envelop the veins or develop in the lavas as concentric shells. The tellurium-bearing Cu-Zn mineralization is developed in two successive stages followed by a supergene stage. The Co-pyrite- chalcopyrite geothermometer defined two stages of sulphide equilibrium: 310° to 375°C (Stage I), and 220° to 260°C (Stage II). The calculated ÎŽ180 and \u3c5D compositions of the waters reflect the dominance of a magmatic component. The calculated ÎŽ3^Î^ fluid values also reveal a magmatic source for the sulphur, with minor contribution from submarine sediments, whereas tellurium is proposed to be derived from a mafic-ultramafic source. The physicochemical conditions of the hydrothermal fluids in the Hermione system were T=250°-300°C, P ~ 450 bars, pH =j61 to 530,fS2 HS aq) : = 10\u2711·6 to 10-12·4,fo2 = 10-35·5 to 10-38·3, logaH2S(aq) = 10\u273\u277 to 10\u2740, and loga = 10\u271 2·6 to 10-3·4
Potentially active regions on Titan: New processing of Cassini/VIMS data
The Cassini Visual and Infrared Mapping Spectrometer (VIMS) obtained data of Titan's surface from flybys performed during the last seven years. In the 0.8-5.2 ”m range, these spectro-imaging data showed that the surface consists of a multivariable geological terrain hosting complex geological processes. The data from the seven narrow methane spectral "windows" centered at 0.93, 1.08, 1.27, 1.59, 2.03, 2.8 and 5 ”m provide some information on the lower atmospheric context and the surface parameters that we want to determine. Atmospheric scattering and absorption need to be clearly evaluated before we can extract the surface properties. We apply here a statistical method [1, 2] and a radiative transfer method [3, 1] on three potentially "active" regions on Titan, i.e. regions possibly subject to change over time (in brightness and/or in color etc) [4]: Tui Regio (20°S, 130°W) [5], a 1,500-km long flow-like figure, Hotei Regio (26°S, 78°W) [6], a 700-km wide volcanic-like terrain, and Sotra Facula (15°S, 42°W) [7], a 235-km in diameter area. With our method of Principal Component Analysis (PCA) we have managed to isolate specific regions of distinct and diverse chemical composition. We have tested this method on the previously studied Sinlap crater [8], delimitating compositional heterogeneous areas compatible with the published conclusions by Le Mouélic et al. (2008). Our follow-up method focuses on retrieving the surface albedo of the three areas and of the surrounding terrains with different spectral response by applying a radiative transfer (RT) code. We have used as input most of the Cassini HASI and DISR measurements, as well as new methane absorption coefficients [9], which are important to evaluate the atmospheric contribution and to allow us to better constrain the real surface alterations, by comparing the spectra of these regions. By superposing these results onto the PCA maps, we can correlate composition and morphology. As a test case, we used our RT code to verify the varying brightness of Hotei Regio reported by other investigators based on models lacking proper simulation of the atmospheric absorption [10]. Even though we have used exactly the same dataset, we did not detect any significant surface albedo variations over time; this led us to revise the definition of "active" regions: even if these regions have not visually changed over the course of the Cassini mission, the determination of the chemical composition and the correlation with the morphological structures [11] observed in these areas do not rule out that past and/or ongoing cryovolcanic processes are still a possible interpretation. [1] Solomonidou, A. et al. (2011). Potentially active regions on Titan: New processing of Cassini/VIMS data. In preparation. [2] Stephan, K. et al. (2008). Reduction of instrument-dependent noise in hyperspectral image data using the principal component analysis: Applications to Galileo NIMS data. Planetary and Space Science 56, 406-419. [3] Hirtzig, M. et al. (2011). Applications of a new methane linelist to Cassini/VIMS spectra of Titan in the 1.28-5.2 ”m range . In preparation. [4] Wall, s. D. et al. (2009). Cassini RADAR images at Hotei Arcus and western Xanadu, Titan: Evidence for geologically recent cryovolcanic activity. Journal of Geophysical Research 36, L04203, [5] Barnes, J.W. et al. (2006). Cassini observations of flow-like features in western Tui Regio, Titan. Geophysical Research Letters 33, L16204. [6] Soderblom, L.A. et al. (2009). The geology of Hotei Regio, Titan: Correlation of Cassini VIMS and RADAR. Icarus 204, 610-618. [7] Lopes, R.M.C. et al. (2010). Distribution and interplay of geologic processes on Titan from Cassini radar data. Icarus 205, 540-558. [8] Le Mouélic et al. (2008). Mapping and interpretation of Sinlap crater on Titan using Cassini VIMS and RADAR data. Journal of Geophysical Research 113, E04003. [9] Campargue, A. et al. (2011). An empirical line list for methane at 80 K and 296 K in the 1.26-1.71 ”m region for planetary investigations. Application to Titan. Icarus. Submitted. [10] Nelson, R. et al (2009). Saturn's Titan: Surface change, ammonia, and implications for atmospheric and tectonic activity. Icarus 199, 429-441. [11] Solomonidou, A. et al. (2011). Possible morphotectonic features on Titan and their origin. Planetary and Space Science. Submitted
Cognitive flexibility predicts early reading skills
International audienceAn important aspect of learning to read is efficiency in accessing different kinds of linguistic information (orthographic, phonological, and semantic) about written words. The present study investigates whether, in addition to the integrity of such linguistic skills, early progress in reading may require a degree of cognitive flexibility in order to manage the coordination of this information effectively. Our study will look for evidence of a link between flexibility and both word reading and passage reading comprehension, and examine whether any such link involves domain-general or reading-specific flexibility. As the only previous support for a predictive relationship between flexibility and early reading comes from studies of reading comprehension in the opaque English orthography, another possibility is that this relationship may be largely orthography-dependent, only coming into play when mappings between representations are complex and polyvalent. To investigate these questions, 60 second-graders learning to read the more transparent French orthography were presented with two multiple classification tasks involving reading-specific cognitive flexibility (based on words) and non-specific flexibility (based on pictures). Reading skills were assessed by word reading, pseudo-word decoding, and passage reading comprehension measures. Flexibility was found to contribute significant unique variance to passage reading comprehension even in the less opaque French orthography. More interestingly, the data also show that flexibility is critical in accounting for one of the core components of reading comprehension, namely, the reading of words in isolation. Finally, the results constrain the debate over whether flexibility has to be reading-specific to be critically involved in reading
The evolution of a W, Au-Ag-Te and Au-Ag hydrothermal system, Tinos Island, Cyclades, Greece
At Tinos Island, Greece, the physicochemical evolution of the hydrothermal system and the associated stages of metallic mineralization that are developed in the vicinity of the Tinos granodiorite-leucogranite has been studied, based on fluid inclusion studies and chemical reactions modeling. Early tungsten mineraliozation was related to the metasomatic stage of contact metamorphism and precipitated at ~ 350oC, from moderate saline (10.4 to 14.8 wt% NaCl eq.), CO2- effervescing fluids, that contained variable amounts of CaCl2 and MgCl2. Panormos Bay Au-Ag-Te mineralization, located 16 km away from the intrusive site, was deposited from cooler 200° to 300oC, and low to moderate saline (0.2 to 13.2 wt% NaCl eq.) mineralizing fluids. Au-Ag mineralization at Apigania Bay, which represents a late evolutionary phase, was deposited from even cooler (125o to 235oC) and dilute (0.2 to 6.8 wt % NaCl eq.) fluids. In all, the mineralization stage precipitation was controlled by two principal factors: the exsolution of gaseous phase and an increase in pH from 3.3 to 7.6
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