Theoretical Description of Two- and Three-Particle Interactions in Single Ionization of Helium by Ion Impact

In this work we calculate doubly differential cross sections (DDCS) for single ionization of helium by highly charged ion impact. We study the importance of two-particle interactions in these processes by considering the cross sections as a function of all two-particle subsystems momenta. Experimental DDCSs were obtained recently from kinematically complete experiments on single ionization of He by 100 MeV/amu C6+ and 3.6 MeV/amu Au24,53+ impact. Furthermore, we evaluated the importance of three-particle interactions by plotting the squared momenta of all three collision fragments simultaneously in a Dalitz plot. Using the first Born and distorted-wave approximations for fully differential cross sections, together with Monte Carlo integration techniques, we were able to reproduce the main features observed in experimental data and to assess the quality of the models implied by the different employed approximations

Statistical analysis of geochemical data: a tool for discriminating between kaolin deposits of hypogene and supergene origin, Patagonia, Argentina

The numerous kaolin deposits located in Patagonia, Argentina, have been formed by hypogene or supergene processes. The primary origin has been established from O18 and D isotopic composition of the main minerals, kaolinite and/or dickite, and from the behaviour of certain elements during the alteration. The aim of this paper was to find if there is a tool, other than oxygendeuterium data, to establish the origin of the Patagonian kaolin deposits. To handle the large number of variables per sample, a statistical multivariate study was used. The Principal Component method defines, on one hand the variables that better characterize each deposit and, on the other hand, the correlation between them. Fifty seven elements were considered and those that were not explained using these two components (which represent 75% of the total variance of the model) were discarded. As a result, the contents of Fe2O3, P2O5, LOI, Sr, Y, Zr, V, Pb, Hf, Rb, S and REE were used and the results show that the two components separate the deposits into two fields that are consistent with the process of formation. The first component indicates that Fe2O3, Y, Rb, U and HREE are more abundant in the supergene deposits, whereas, Sr, Pb, S and V are more abundant in the hypogene deposits. The second component shows that S, P2O5 and the LREE are enriched in the hydrothermal deposits, whereas Zr is more abundant in those formed under weathering conditions

Controller of a new pulsed source for linac 4 (MEGADISCAP)

This document presents the implementation of a control system for a new multiple-stage pulsed current source converter. A new topology that has been proposed to overcome some limitations inherent to capacitor discharge converter is presented in detail and explained. Its implementation is described and the design considerations adopted are accounted for. Besides, a control strategy is proposed, which has been implemented using an existing control board with some modifications on the acquisition system. A prototype whose current and voltage are scaled down with respect to those required for the converters that will be used for CERN Booster injection with LINAC 4 has been built. This reduced scale system has been simulated taking into account the control system implementation. Finally, the topology operating principle has been validated, the results obtained with the scaled down prototype have been compared with simulations and the need for more hardware resources for the control system implementation has been demonstrated

Post-Prior discrepancies in CDW-EIS calculations for ion impact ionization fully differential cross sections

In this work we present fully differential cross sections (FDCSs) calculations using post and prior version of CDW--EIS theory for helium single ionization by 100 MeV C$^{6+}$ amu$^{-1}$ and 3.6 MeV amu$^{-1}$ Au$^{24+}$ and Au$^{53+}$ ions. We performed our calculations for different momentum transfer and ejected electron energies. The influence of internuclear potential on the ejected electron spectra is taken into account in all cases. We compare our calculations with absolute experimental measurements. It is shown that prior version calculations give better agreement with experiments in almost all studied cases.Comment: 9 pages, 7 figure

Cannabinoids activate the insulin pathway to modulate mobilization of cholesterol in C. elegans

The nematode Caenorhabditis elegans requires exogenous cholesterol to survive and its depletion leads to early developmental arrest. Thus, tight regulation of cholesterol storage and distribution within the organism is critical. Previously, we demonstrated that the endocannabinoid (eCB) 2-arachidonoylglycerol (2-AG) plays a key role in C. elegans since it modulates sterol mobilization. However, the mechanism remains unknown. Here we show that mutations in the ocr-2 and osm-9 genes, coding for transient receptors potential V (TRPV) ion channels, dramatically reduce the effect of 2-AG in cholesterol mobilization. Through genetic analysis in combination with the rescue of larval arrest induced by sterol starvation, we found that the insulin/IGF-1signaling (IIS) pathway and UNC-31/CAPS, a calcium-activated regulator of neural dense-core vesicles release, are essential for 2-AG-mediated stimulation of cholesterol mobilization. These findings indicate that 2-AG-dependent cholesterol trafficking requires the release of insulin peptides and signaling through the DAF-2 insulin receptor. These results suggest that 2-AG acts as an endogenous modulator of TRPV signal transduction to control intracellular sterol trafficking through modulation of the IGF-1 signaling pathwayFil: Hernández Cravero, Bruno. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario. Laboratorio de Fisiología Microbiana (IBR-CONICET); Argentina.Fil: Vranych, Cecilia V. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario. Laboratorio de Fisiología Microbiana (IBR-CONICET); Argentina.Fil: De Mendoza, Diego. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario. Laboratorio de Fisiología Microbiana (IBR-CONICET); Argentina.Fil: GallinoI, Sofía. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres". Laboratorio de Fisiología y Genética de la Audición (INGEBI-CONICET); Argentina.Fil: Elgoyhen, Ana Belén. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres". Laboratorio de Fisiología y Genética de la Audición (INGEBI-CONICET); Argentina.Fil: Florman, Jeremy. University of Massachusetts Medical School. Department of Neurobiology; United States.Fil: AlkemaI, Mark J. University of Massachusetts Medical School. Department of Neurobiology; United States.Fil: Diaz, Philippe. University of Montana. Department of Biomedical and Pharmaceutical Sciences; United States

QSAR Classification Models for Predicting the Activity of Inhibitors of Beta-Secretase (BACE1) Associated with Alzheimer’s Disease

Alzheimer’s disease is one of the most common neurodegenerative disorders in elder population. The β-site amyloid cleavage enzyme 1 (BACE1) is the major constituent of amyloid plaques and plays a central role in this brain pathogenesis, thus it constitutes an auspicious pharmacological target for its treatment. In this paper, a QSAR model for identification of potential inhibitors of BACE1 protein is designed by using classification methods. For building this model, a database with 215 molecules collected from different sources has been assembled. This dataset contains diverse compounds with different scaffolds and physical-chemical properties, covering a wide chemical space in the drug-like range. The most distinctive aspect of the applied QSAR strategy is the combination of hybridization with backward elimination of models, which contributes to improve the quality of the final QSAR model. Another relevant step is the visual analysis of the molecular descriptors that allows guaranteeing the absence of information redundancy in the model. The QSAR model performances have been assessed by traditional metrics, and the final proposed model has low cardinality, and reaches a high percentage of chemical compounds correctly classified.Fil: Ponzoni, Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias e Ingeniería de la Computación. Universidad Nacional del Sur. Departamento de Ciencias e Ingeniería de la Computación. Instituto de Ciencias e Ingeniería de la Computación; Argentina. Universidad Nacional del Sur. Departamento de Ciencias e Ingeniería de la Computación. Instituto de Ciencias e Ingeniería de la Computación; ArgentinaFil: Sebastián Pérez, Víctor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias e Ingeniería de la Computación. Universidad Nacional del Sur. Departamento de Ciencias e Ingeniería de la Computación. Instituto de Ciencias e Ingeniería de la Computación; Argentina. Consejo Superior de Investigaciones Científicas. Centro de Investigaciones Biológicas; EspañaFil: Martínez, María J.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias e Ingeniería de la Computación. Universidad Nacional del Sur. Departamento de Ciencias e Ingeniería de la Computación. Instituto de Ciencias e Ingeniería de la Computación; Argentina. Universidad Nacional del Sur. Departamento de Ciencias e Ingeniería de la Computación. Instituto de Ciencias e Ingeniería de la Computación; ArgentinaFil: Roca, Carlos. Consejo Superior de Investigaciones Científicas. Centro de Investigaciones Biológicas; EspañaFil: De la Cruz Pérez, Carlos. Consejo Superior de Investigaciones Científicas. Centro de Investigaciones Biológicas; EspañaFil: Cravero, Fiorella. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Vazquez, Gustavo Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Católica del Uruguay; UruguayFil: Páez, Juan A.. Consejo Superior de Investigaciones Científicas. Instituto de Química Médica; EspañaFil: Diaz, Monica Fatima. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; ArgentinaFil: Campillo Martín, Nuria Eugenia. Consejo Superior de Investigaciones Científicas. Centro de Investigaciones Biológicas; Españ

The CERN PS multi-turn extraction based on beam splittting in stable islands of transverse phase space: Design Report

Since 2001 considerable effort has been devoted to the study of a possible replacement of the continuous-transfer extraction mode from the PS to the SPS. Such an approach, called Multi-Turn Extraction (MTE), is based on capture of the beam inside stable islands of transverse phase space, generated by sextupoles and octupoles, thanks to a properly chosen tune variation. Both numerical simulations and measurements with beam were performed to understand the properties of this new extraction mode. The experimental study was completed at the end of 2004 and by the end of 2005 a scheme to implement this novel approach in the PS machine was defined and its performance assessed. This design report presents the outcome of the studies undertaken both in terms of technical issues as well as of resources necessary to implement the proposed scheme

A facile and green route to terpene derived acrylate and methacrylate monomers and simple free radical polymerisation to yield new renewable polymers and coatings

We present new acrylic monomers derived directly from abundant naturally available terpenes via a facile, green and catalytic approach. These monomers can be polymerised to create new polymers with a wide range of mechanical properties that positions them ideally for application across the commodity and specialty plastics landscape; from packaging, cosmetic and medical, through to composites and coatings. We demonstrate their utility through formation of novel renewable polymer coatings

Tensile Strength of Geological Discontinuities Including Incipient Bedding, Rock Joints and Mineral Veins

Geological discontinuities have a controlling influence for many rock-engineering projects in terms of strength, deformability and permeability, but their characterisation is often very difficult. Whilst discontinuities are often modelled as lacking any strength, in many rock masses visible rock discontinuities are only incipient and have tensile strength that may approach and can even exceed that of the parent rock. This fact is of high importance for realistic rock mass characterisation but is generally ignored. It is argued that current ISRM and other standards for rock mass characterisation, as well as rock mass classification schemes such as RMR and Q, do not allow adequately for the incipient nature of many rock fractures or their geological variability and need to be revised, at least conceptually. This paper addresses the issue of the tensile strength of incipient discontinuities in rock and presents results from a laboratory test programme to quantify this parameter. Rock samples containing visible, natural incipient discontinuities including joints, bedding, and mineral veins have been tested in direct tension. It has been confirmed that such discontinuities can have high tensile strength, approaching that of the parent rock. Others are, of course, far weaker. The tested geological discontinuities all exhibited brittle failure at axial strain less than 0.5 % under direct tension conditions. Three factors contributing to the tensile strength of incipient rock discontinuities have been investigated and characterised. A distinction is made between sections of discontinuity that are only partially developed, sections of discontinuity that have been locally weathered leaving localised residual rock bridges and sections that have been ‘healed’ through secondary cementation. Tests on bedding surfaces within sandstone showed that tensile strength of adjacent incipient bedding can vary considerably. In this particular series of tests, values of tensile strength for bedding planes ranged from 32 to 88 % of the parent rock strength (intact without visible discontinuities), and this variability could be attributed to geological factors. Tests on incipient mineral veins also showed considerable scatter, the strength depending upon the geological nature of vein development as well as the presence of rock bridges. As might be anticipated, tensile strength of incipient rock joints decreases with degree of weathering as expressed in colour changes adjacent to rock bridges. Tensile strengths of rock bridges (lacking marked discolouration) were found to be similar to that of the parent rock. It is concluded that the degree of incipiency of rock discontinuities needs to be differentiated in the process of rock mass classification and engineering design and that this can best be done with reference to the tensile strength relative to that of the parent rock. It is argued that the science of rock mass characterisation may be advanced through better appreciation of geological history at a site thereby improving the process of prediction and extrapolating properties