333 research outputs found

    Relevance of nucleon spin in amplitude analysis of reactions pi(-)p->pi(0)pi(0)n and pi(-)p->eta eta n

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    The measurements of reactions π−p→π−π+n\pi^- p \to \pi^- \pi^+ n and π+n→π+π−p\pi^+ n \to \pi^+ \pi^- p on polarized targets at CERN found a strong dependence of pion production amplitudes on nucleon spin. Analyses of recent measurements of π−p→π0π0n\pi^- p \to \pi^0\pi^0 n reaction on unpolarized targets by GAMS Collaboration at 38 GeV/c and BNL E852 Collaboration at 18 GeV/c use the assumption that pion production amplitudes do not depend on nucleon spin, in conflict with the CERN results on polarized targets. We show that measurements of π−p→π0π0n\pi^- p \to \pi^0\pi^0 n and π−p→ηηn\pi^- p \to \eta\eta n on unpolarized targets can be analysed in a model independent way in terms of 4 partial-wave intensities and 3 independent interference phases in the mass region where SS- and DD-wave dominate. We also describe model-independent amplitude analysis of π−p→π0π0n\pi^- p \to \pi^0\pi^0 n reaction measured on polarized target, both in the absence and in the presence of GG-wave amplitudes. We suggest that high statistics measurements of reactions π−p→π0π0n\pi^- p \to \pi^0 \pi^0 n and π−p→ηηn\pi^- p \to \eta\eta n be made on polarized targets at Protvino IHEP and at BNL, and that model-independent amplitude analyses of this polarized data be performed to advance hadron spectroscopy on the level of spin dependent production amplitudes.Comment: 54 page

    Ionising radiation metrology for the metallurgical industry

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    Every year millions tons of steel are produced worldwide from recycled scrap loads. Although the detection systems in the steelworks prevent most orphan radioactive sources from entering the furnace, there is still the possibility of accidentally melting a radioactive source. The MetroMetal project, carried out in the frame of the European Metrology Research Programme (EMRP), addresses this problem by studying the existing measurement systems, developing sets of reference sources in various matrices (cast steel, slag, fume dust) and proposing new detection instruments. This paper presents the key lines of the project and describes the preparation of radioactive sources as well as the intercomparison exercises used to test the calibration and correction methods proposed within the project.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

    Soft-core hyperon-nucleon potentials

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    A new Nijmegen soft-core OBE potential model is presented for the low-energy YN interactions. Besides the results for the fit to the scattering data, which largely defines the model, we also present some applications to hypernuclear systems using the G-matrix method. An important innovation with respect to the original soft-core potential is the assignment of the cut-off masses for the baryon-baryon-meson (BBM) vertices in accordance with broken SU(3)F_F, which serves to connect the NN and the YN channels. As a novel feature, we allow for medium strong breaking of the coupling constants, using the 3P0^3P_0 model with a Gell-Mann--Okubo hypercharge breaking for the BBM coupling. We present six hyperon-nucleon potentials which describe the available YN cross section data equally well, but which exhibit some differences on a more detailed level. The differences are constructed such that the models encompass a range of scattering lengths in the ΣN\Sigma N and ΛN\Lambda N channels. For the scalar-meson mixing angle we obtained values ξS=37\theta_S=37 to 40 degrees, which points to almost ideal mixing angles for the scalar qqˉq\bar{q} states. The G-matrix results indicate that the remarkably different spin-spin terms of the six potentials appear specifically in the energy spectra of Λ\Lambda hypernuclei.Comment: 37 pages, 4 figure

    The Fast Read-out System for the MAPMTs of COMPASS RICH-1

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    A fast readout system for the upgrade of the COMPASS RICH detector has been developed and successfully used for data taking in 2006 and 2007. The new readout system for the multi-anode PMTs in the central part of the photon detector of the RICH is based on the high-sensitivity MAD4 preamplifier-discriminator and the dead-time free F1-TDC chip characterized by high-resolution. The readout electronics has been designed taking into account the high photon flux in the central part of the detector and the requirement to run at high trigger rates of up to 100 kHz with negligible dead-time. The system is designed as a very compact setup and is mounted directly behind the multi-anode photomultipliers. The data are digitized on the frontend boards and transferred via optical links to the readout system. The read-out electronics system is described in detail together with its measured performances.Comment: Proceeding of RICH2007 Conference, Trieste, Oct. 2007. v2: minor change

    Fast Photon Detection for Particle Identification with COMPASS RICH-1

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    Particle identification at high rates is an important challenge for many current and future high-energy physics experiments. The upgrade of the COMPASS RICH-1 detector requires a new technique for Cherenkov photon detection at count rates of several 10610^6 per channel in the central detector region, and a read-out system allowing for trigger rates of up to 100 kHz. To cope with these requirements, the photon detectors in the central region have been replaced with the detection system described in this paper. In the peripheral regions, the existing multi-wire proportional chambers with CsI photocathode are now read out via a new system employing APV pre-amplifiers and flash ADC chips. The new detection system consists of multi-anode photomultiplier tubes (MAPMT) and fast read-out electronics based on the MAD4 discriminator and the F1-TDC chip. The RICH-1 is in operation in its upgraded version for the 2006 CERN SPS run. We present the photon detection design, constructive aspects and the first Cherenkov light in the detector.Comment: Proceedings of the Imaging 2006 conference, Stockholm, Sweden, 27-30 June 2006, 5 pages, 6 figures, to appear in NIM A; corrected typo in caption of Fig.

    Fast photon detection for the COMPASS RICH detector

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    The COMPASS experiment at the SPS accelerator at CERN uses a large scale Ring Imaging CHerenkov detector (RICH) to identify pions, kaons and protons in a wide momentum range. For the data taking in 2006, the COMPASS RICH has been upgraded in the central photon detection area (25% of the surface) with a new technology to detect Cherenkov photons at very high count rates of several 10^6 per second and channel and a new dead-time free read-out system, which allows trigger rates up to 100 kHz. The Cherenkov photons are detected by an array of 576 visible and ultra-violet sensitive multi-anode photomultipliers with 16 channels each. The upgraded detector showed an excellent performance during the 2006 data taking.Comment: Proceeding of the IPRD06 conference (Siena, Okt. 06

    Analysis of data on low energy piN-->pipiN reaction. I. Total cross sections

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    This is the first of a series of papers on a consistent model independent analysis of the complete experimental information on the reaction πN→ππN\pi N \rightarrow \pi \pi N at pion momenta up to 500 MeV/c. The paper summarizes the theoretical approach and details of the computational procedure. The complete database on total cross sections in 5 ππN\pi \pi N channels is given together with a critical discussion of their model independent analysis.Comment: 45 page

    Mechanism of Human Papillomavirus Binding to Human Spermatozoa and Fertilizing Ability of Infected Spermatozoa

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    Human papillomaviruses (HPVs) are agents of the most common sexually transmitted diseases in females and males. Precise data about the presence, mechanism of infection and clinical significance of HPV in the male reproductive tract and especially in sperm are not available. Here we show that HPV can infect human sperm, it localizes at the equatorial region of sperm head through interaction between the HPV capsid protein L1 and syndecan-1. Sperm transfected with HPV E6/E7 genes and sperm exposed to HPV L1 capsid protein are capable to penetrate the oocyte and transfer the virus into oocytes, in which viral genes are then activated and transcribed. These data show that sperm might function as vectors for HPV transfer into the oocytes, and open new perspectives on the role of HPV infection in males and are particularly intriguing in relation to assisted reproduction techniques

    Identifying Low pH Active and Lactate-Utilizing Taxa within Oral Microbiome Communities from Healthy Children Using Stable Isotope Probing Techniques

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    <div><h3>Background</h3><p>Many human microbial infectious diseases including dental caries are polymicrobial in nature. How these complex multi-species communities evolve from a healthy to a diseased state is not well understood. Although many health- or disease-associated oral bacteria have been characterized <em>in vitro</em>, their physiology within the complex oral microbiome is difficult to determine with current approaches. In addition, about half of these species remain uncultivated to date with little known besides their 16S rRNA sequence. Lacking culture-based physiological analyses, the functional roles of uncultivated species will remain enigmatic despite their apparent disease correlation. To start addressing these knowledge gaps, we applied a combination of Magnetic Resonance Spectroscopy (MRS) with RNA and DNA based Stable Isotope Probing (SIP) to oral plaque communities from healthy children for <em>in vitro</em> temporal monitoring of metabolites and identification of metabolically active and inactive bacterial species.</p> <h3>Methodology/Principal Findings</h3><p>Supragingival plaque samples from caries-free children incubated with <sup>13</sup>C-substrates under imposed healthy (buffered, pH 7) and diseased states (pH 5.5 and pH 4.5) produced lactate as the dominant organic acid from glucose metabolism. Rapid lactate utilization upon glucose depletion was observed under pH 7 conditions. SIP analyses revealed a number of genera containing cultured and uncultivated taxa with metabolic capabilities at pH 5.5. The diversity of active species decreased significantly at pH 4.5 and was dominated by <em>Lactobacillus</em> and <em>Propionibacterium</em> species, both of which have been previously found within carious lesions from children.</p> <h3>Conclusions/Significance</h3><p>Our approach allowed for identification of species that metabolize carbohydrates under different pH conditions and supports the importance of Lactobacilli and Propionibacterium in the development of childhood caries. Identification of species within healthy subjects that are active at low pH can lead to a better understanding of oral caries onset and generate appropriate targets for preventative measures in the early stages.</p> </div

    Evaporation kinetics in swollen porous polymeric networks

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    Ponencia presentada en el Congreso Euromar 2014.Fil: Velasco, Manuel Isaac. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Instituto de FĂ­sica Enrique Gaviola; Argentina.Fil: Silletta, Emilia Victoria. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Instituto de FĂ­sica Enrique Gaviola; Argentina.Fil: Monti, Gustavo Alberto. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Instituto de FĂ­sica Enrique Gaviola; Argentina.Fil: Acosta, Rodolfo HĂ©ctor. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Instituto de FĂ­sica Enrique Gaviola; Argentina.Fil: Velasco, Manuel Isaac. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂ­a y FĂ­sica; Argentina.Fil: Silletta, Emilia Victoria. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂ­a y FĂ­sica; Argentina.Fil: Monti, Gustavo Alberto. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂ­a y FĂ­sica; Argentina.Fil: Acosta, Rodolfo HĂ©ctor. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂ­a y FĂ­sica; Argentina.Fil: Gomez, Cesar Gerardo. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂ­micas. Departamento de QuĂ­mica OrgĂĄnica; Argentina.Fil: Strumia, Miriam Cristina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂ­micas. Departamento de QuĂ­mica OrgĂĄnica; Argentina.Fil: Gomez, Cesar Gerardo. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Instituto Multidisciplinario de BiologĂ­a Vegetal; Argentina.Fil: Gomez, Cesar Gerardo. Universidad Nacional de CĂłrdoba. Instituto Multidisciplinario de BiologĂ­a Vegetal; Argentina.Fil: Strumia, Miriam Cristina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Instituto Multidisciplinario de BiologĂ­a Vegetal; Argentina.Fil: Strumia, Miriam Cristina. Universidad Nacional de CĂłrdoba. Instituto Multidisciplinario de BiologĂ­a Vegetal; Argentina.Polymer matrices with well defined structure and pore sizes are widely used in several areas of chemistry such as catalysis, enzyme immobilization, HPLC, adsorbents or controlled drug release. These polymers have pores in its structure both in the dry and swollen state. Although it is well known that the structures and properties greatly differ between these two states, only few methods provide information about the swollen one, even though most of the applications involve the matrices in this situation. Nuclear Magnetic Resonance (NMR) is a suitable tool for the study of the molecular dynamics of different liquids spatially confined in macro, meso and nanopores, through changes in the relaxation times. In transverse relaxation experiments, either diffusion inside the pore, or relaxation induced by mobility restriction of the liquid near the wall, are additional sources of relaxation, which are extremely useful in the determination of structural and functional properties.Fil: Velasco, Manuel Isaac. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Instituto de FĂ­sica Enrique Gaviola; Argentina.Fil: Silletta, Emilia Victoria. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Instituto de FĂ­sica Enrique Gaviola; Argentina.Fil: Monti, Gustavo Alberto. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Instituto de FĂ­sica Enrique Gaviola; Argentina.Fil: Acosta, Rodolfo HĂ©ctor. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Instituto de FĂ­sica Enrique Gaviola; Argentina.Fil: Velasco, Manuel Isaac. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂ­a y FĂ­sica; Argentina.Fil: Silletta, Emilia Victoria. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂ­a y FĂ­sica; Argentina.Fil: Monti, Gustavo Alberto. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂ­a y FĂ­sica; Argentina.Fil: Acosta, Rodolfo HĂ©ctor. Universidad Nacional de CĂłrdoba. Facultad de MatemĂĄtica, AstronomĂ­a y FĂ­sica; Argentina.Fil: Gomez, Cesar Gerardo. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂ­micas. Departamento de QuĂ­mica OrgĂĄnica; Argentina.Fil: Strumia, Miriam Cristina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂ­micas. Departamento de QuĂ­mica OrgĂĄnica; Argentina.Fil: Gomez, Cesar Gerardo. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Instituto Multidisciplinario de BiologĂ­a Vegetal; Argentina.Fil: Gomez, Cesar Gerardo. Universidad Nacional de CĂłrdoba. Instituto Multidisciplinario de BiologĂ­a Vegetal; Argentina.Fil: Strumia, Miriam Cristina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Instituto Multidisciplinario de BiologĂ­a Vegetal; Argentina.Fil: Strumia, Miriam Cristina. Universidad Nacional de CĂłrdoba. Instituto Multidisciplinario de BiologĂ­a Vegetal; Argentina.FĂ­sica de los Materiales Condensado
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