H2O and Cl in deep crustal melts: the message of melt inclusions in metamorphic rocks

The use of NanoSIMS on primary melt inclusions in partially melted rocks is a powerful approach to clarify the budget of volatiles at depth during crust formation and its reworking. Anatectic melt inclusions are indeed gateways to quantify H2O, halogens and other species (e.g. CO2, N) partitioned into the deep partial melts generated during metamorphism of the continental crust. Here we present new datasets of NanoSIMS measurements of H2O and Cl in preserved melt inclusions from metamorphic rocks with different protoliths – magmatic or sedimentary – which underwent partial melting at different pressure–temperature–fluid conditions. These new datasets are then compared with similar data on natural anatectic melts available in the literature to date. Our study provides novel, precise constraints for the H2O content in natural melts formed at high pressure, a field previously investigated mostly via experiments. We also show that H2O heterogeneities in partial melts at the microscale are common, regardless of the rock protolith. Correlations between H2O contents and P–T values can be identified merging new and old data on anatectic inclusions via NanoSIMS. Overall, the data acquired so far indicate that silicate melt generation in nature always requires H2O, even for the hottest melts found so far (&gt;1000 ∘C). Moreover, in agreement with previous work, preserved glassy inclusions always appear to be poorer in H2O than crystallized ones, regardless of their chemical system and/or P–T conditions of formation. Finally, this study reports the very first NanoSIMS data on Cl (often in amounts &gt;1000 ppm) acquired in situ on natural anatectic melts, showing how anatectic melt inclusions – additionally to magmatic ones – may become a powerful tool to clarify the role of halogens in many geological processes, not only in crustal evolution but also in ore deposit formation.</p

Factors affecting the quality of XBT data - results of analyses on profiles from the Western Mediterranean Sea

EXpendable BathyThermograph (XBT) temperature profiles collected in the framework of the Mediterranean Forecasting System - Toward Environmental Prediction (MFS-TEP) project have been compared with CTD measurements. New procedures for the quality control of recorded values have been developed and checked. Some sources of possible uncertainties and errors, such as the response time of the apparatus (XBT probe, thermistor and readout chain), or the influence of initial conditions are also analysed. To deal with the high homogeneity of Mediterranean waters, a new technique to compute the fall rate coefficients, that give a better reproduction of the depth of thermal structures, has been proposed, and new customized coefficients have been calculated. After the application of a temperature correction, the overall uncertainties in depth and in temperature measurements have been estimated

Anisotropic flow from Lee-Yang zeroes: a practical guide

We present a new method to analyze anisotropic flow from the genuine correlation among a large number of particles, focusing on the practical implementation of the method.Comment: 4 pages; contribution to Quark Matter 2004, Oakland, January 11-17, 200

Improved quality check procedures of XBT profiles in MFS-VOS

International audienceSippican T4/DB XBT profiles, collected in the framework of Mediterranean Forecasting System ? Toward Environmental Prediction, are analysed, namely the possible influence of launching position height, ship speed and of probes' characteristics. Comparison of XBT vs CTD profiles have suggested some changes in quality control procedures and, more important, in the values of fall rate coefficients customised for the Mediterranean. The effects of these new procedures on the overall uncertainty on depth and on temperature measurements are estimated

Multiplicity distributions inside parton cascades developing in a medium

The explanation of the suppression of high-pT hadron yields at RHIC in terms of jet-quenching implies that the multiplicity distributions of particles inside a jet and jet-like particle correlations differ strongly in nucleus-nucleus collisions at RHIC or at the LHC from those observed at e+e- or hadron colliders. We present a framework for describing the medium-induced modification, which has a direct interpretation in terms of a probabilistic medium-modified parton cascade, and which treats leading and subleading partons on an equal footing. We show that our approach can account for the strong suppression of single inclusive hadron spectra measured in Au-Au collisions at RHIC, and that this implies a characteristic distortion of the single inclusive distribution of soft partons inside the jet. We determine, as a function of the jet energy, to what extent the soft fragments within a jet can be measured above some momentum cut.Comment: 5 pages, 4 eps-figures; talk given at Hot Quarks 2006, Villasimius (Sardinia, Italy), May 15-20, 200

Elliptic Flow Analysis at RHIC with the Lee-Yang Zeroes Method in a Relativistic Transport Approach

The Lee-Yang zeroes method is applied to study elliptic flow ($v_2$) in Au+Au collisions at $\sqrt{s}=200A$~GeV, with the UrQMD model. In this transport approach, the true event plane is known and both the nonflow effects and event-by-event $v_2$ fluctuations exist. Although the low resolutions prohibit the application of the method for most central and peripheral collisions, the integral and differential elliptic flow from the Lee-Yang zeroes method agrees with the exact $v_2$ values very well for semi-central collisions.Comment: 4 pages, 4 figure

The mechanical design of a gas supply and mixing system for the AMS-02 particle detector onboard the international space station

Abstract The Alpha Magnetic Spectrometer 02 is a particle physics experiment that will search for antimatter, dark matter, and measure cosmic rays in space aboard the International space station for 3 years . It is comprised of an array of sub-detectors: Transition Radiation Detector (TRD); Time of Flight detector; Anti-Coincidence Counter; Silicon Tracker; Ring Imaging Cherenkov counter; Electromagnetic Calorimeter and requires the operation of a cryogenic super conducting magnet at its core. It is built by an international collaboration of more than 100 scientists spread all over Europe, USA and the far East. The TRD that is located above the Cryomagnet and Upper Time of Flight, consists of several layers of straw modules interleaved with a fiber fleece material and arranged in a conical octagon structure built out of a carbon fiber/aluminum honeycomb sandwich. A charged particle traversing this detector produces characteristic electromagnetic radiation in each layer that is measured in the gas filled array of straw tubes. From this, the mass and momentum of the particle can be measured provided the tubes are filled with the proper gas mixture. The TRD gas supply stores 50 kg of gas corresponding to 8100 l Xe and 2000 l CO2 at 1 atm , filters, mixes, recirculates, and purges a daily supply of Xe/CO2 (80%/20%) gaseous mixture, thus supplying the TRD with clean, mixed gas for the 3-year ISS mission. Designing and building this reliable, weight optimised system to withstand launch loads and the harsh space environment presented a formidable engineering challenge. Adding to the complexity of the system was that a flexible valve/pump arrangement was needed to control mixture ratio, circulation flow and pressure, and purging. These studies are presented in the paper

Jet multiplicities as the QGP thermometer

It is proposed to use the energy behavior of mean multiplicities of jets propagating in a nuclear medium as the thermometer of this medium during the collision phases. The qualitative effects are demonstrated in the framework of the fixed coupling QCD with account of jet quenching.Comment: Modify version of hep-ph/0509344, 3 figure

Indication of recent warming process at the intermediate level in the Tyrrhenian Sea from SOOP XBT measurements

The Tyrrhenian Sea is a sub-basin of the western Mediterranean crossed by intermediate and deep waters from the eastern basin. Across this sub-basin, temperature profiles of the water column from expendable bathythermographs (XBT) have been acquired for sixteen years along transects realized thanks to the use of commercial vessels. Since 1999 an increase of temperature has been observed at intermediate depths even if interspersed with periods of decrease. This increase involves deeper and deeper depths along the years then involving the whole sub-basin in the range 200-800 m in September 2014 when largest anomalies over the whole period are found. The paper shows evidences of this rapid heating, giving insights into the origin and the diffusion of the warmer intermediate waters then showing its evolution in years and its relationship with the Eastern Mediterranean Transient

Beneficial effects of a low-nickel diet on relapsing IBS-like and extraintestinal symptoms of celiac patients during a proper gluten-free diet: nickel allergic contact mucositis in suspected non-responsive celiac disease

Background and Aim: Nickel (Ni)-rich foods can induce allergic contact mucositis (ACM) with irritable bowel syndrome (IBS)-like symptoms in predisposed subjects. Ni ACM has a high prevalence (&gt;30%) in the general population and can be diagnosed by a Ni oral mucosa patch test (omPT). Many celiac disease (CD) patients on a gluten-free diet (GFD) often show a recrudescence of gastrointestinal and extraintestinal symptoms, although serological and histological remission has been achieved. Since a GFD often results in higher loads of ingested alimentary Ni (e.g., corn), we hypothesized that it would lead to a consequent intestinal sensitization to Ni in predisposed subjects. We wanted to (1) study Ni ACM prevalence in still symptomatic CD patients on a GFD and (2) study the effects of a low-Ni diet (LNiD) on their recurrent symptoms. Material and Methods: We recruited 102 consecutive CD patients (74 female, 28 male; age range 18–65 years, mean age 42.3 ± 7.4) on a GFD since at least 12 months, in current serological and histological remission (Marsh–Oberhuber type 0–I) who complained of relapsing gastrointestinal and/or extraintestinal symptoms. Inclusion criteria: presence of at least three gastrointestinal symptoms with a score ≥5 on the modified Gastrointestinal Symptom Rating Scale (GSRS) questionnaire. Exclusion criteria: IgE-mediated food allergy; history of past or current cancer; inflammatory bowel diseases; infectious diseases including Helicobacter pylori; lactose intolerance. All patients enrolled underwent Ni omPT and followed a LNiD for 3 months. A 24 symptoms questionnaire (GSRS modified according to the Salerno Experts’ Criteria, with 15 gastrointestinal and 9 extraintestinal symptoms) was administered at T0 (free diet), T1 (GFD, CD remission), T2 (recurrence of symptoms despite GFD), and T3 (GFD + LNiD) for comparisons. Comparisons were performed using Wilcoxon signed-rank test. RESULTS: Twenty patients (all female, age range 23–65 years, mean age 39.1 ± 2.9) out of 102 (19.6%) were finally included. All 20 patients enrolled (100%) showed positive Ni omPT, confirming an Ni ACM diagnosis. A correct GFD (T0 vs. T1) induced the improvement of 19 out of the total 24 (79.2%) symptoms, and 14 out of 24 (58.3%) were statistically significant (p-value &lt;0.0083 according to Bonferroni correction). Prolonged GFD (T1 vs. T2) revealed the worsening of 20 out of the total 24 (83.3%) symptoms, and 10 out of 24 (41.7%) were statistically significant. LNiD (T2 vs. T3) determined an improvement of 20 out of the total 24 (83.4%) symptoms, and in 10 out of 24 (41.7%) symptoms the improvement was statistically significant. Conclusions: Our data suggest that the recrudescence of gastrointestinal and extraintestinal symptoms observed in CD subjects during GFD may be due to the increase in alimentary Ni intake, once gluten contamination and persisting villous atrophy are excluded. Ni overload can induce Ni ACM, which can be diagnosed by a specific Ni omPT. Improvement of symptoms occurs after a proper LNiD. These encouraging data should be confirmed with larger studies