Biomarcadores etológicos no invasivos de estrés ambiental: estudio comparativo en dos teleosteos de ecosistemas de la región pampeana argentina

Mediante un dispositivo de registro automático se estudió el efecto de la exposición a soluciones subletales de Cd2+ (0.3 mg. L'1) sobre algunos parámetros etológicos de juveniles de Cyprinus carpió (carpa común) y de Astyanax fasciatus (“mojarra”). Se evaluó el efecto del metal sobre la actividad natatoria total y las preferencias altitudinales y laterales de los peces. Los tres parámetros se registraron simultáneamente mediante un dispositivo original. Se evaluaron los niveles “normales” o estándar de dichos parámetros (los peces en agua potable, control) y los alcanzados por los mismos individuos tras su exposición al tóxico de referencia (Cd). El metal provocó una depresión de la actividad natatoria total alcanzando una magnitud comparable en ambas especies. La preferencia altitudinal, también resultó modificada: C. carpió se halló con mayor frecuencia en la capa superior de los acuarios mientras que A. fasciatus se ubicó en las inferiores. En cuanto a la preferencia lateral, los individuos de ambas especies evitaron la franja vertical donde se producía el goteo de la solución de Cd; si bien esta respuesta espacial de los animales no siguió un patrón definido fue más marcada en las carpas. Todas las respuestas se pusieron de manifiesto inmediatamente después de haberse iniciado la exposición al Cd. El método resultó sensible y apto para el seguimiento de los parámetros etológicos seleccionados. Se concluye que la actividad natatoria y la ubicación espacial de las especies estudiadas, entre otros indicadores, pueden ser considerados como biomarcadores de toxicidad acuática.By means of an automatic recording device, the eífects of the exposure to sublethal Solutions of Cd2+ (0.3 mg. L2) on some ethological parameters of juvenile Cyprinus carpió (common carp) and Astyanaxfasciatus. The effect of the metal was evaluated through three parameters: the total swimming activity and the spatial (lateral and altitudinal) preferences, relative to Controls (fish kept in tap water); they were registered simultaneously by means oían original device. There were determined successively the “normal” or standard levels of those parameters in control fish and those reached by the same individuáis aftertheir exposure to thereferencetoxic (Cd). In both species the metal caused a depression of the total swimming activity in a comparable magnitude. The altitudinal preference was also modified: C. carpió was found more frequently in the superior layer of the aquaria while A. fasciatus was found in the inferior ones. For the lateral preference, the individuáis of both species showed an avoidance behavior of the site of the aquaria where the Cd Solutions was dripping. This response of the animáis didn't follow a defined pattem, but was more marked in the carps. All the evaluated responses to the toxic were detected immediately after the beginning of the exposure to Cd. The method proved to be sensitive and apt for the monitoring of the measured behavioural parameters which makes it a promising tool for biomonitoring purposes. We concluded that the swimming activity and the spatial location preferences of the studied species, among other, may be considered as biomarkers of aquatic toxicity

Simulations and measurements of cleaning with 100 MJ beams in the LHC

The CERN Large Hadron Collider is routinely storing proton beam intensities of more than 100 MJ, which puts extraordinary demands on the control of beam losses to avoid quenches of the superconducting magnets. Therefore, a detailed understanding of the LHC beam cleaning is required. We present tracking and shower simulations of the LHC's multi-stage collimation system and compare with measured beam losses, which allow us to conclude on the predictive power of the simulations.Asian Committee for Future Accelerators (ACFA),American Physical Society Division of Physics of Beams (APS-DPB),Chinese Academy of Sciences (CAS),European Physical Society Accelerator Group (EPS-AG)peer-reviewe

WARP: a double phase Argon programme for Dark Matter detection

WARP (Wimp ARgon Programme) is a double phase Argon detector for Dark Matter detection under construction at Laboratori Nazionali del Gran Sasso. We present recent results obtained operating deep underground a prototype detector with sensitive mass 2.3 litres. 1. WARP: a double phase argon detector for Dark Matter detection. A double phase Argon detector offers unique sensitivity for the search of dark matter in the form of WIMPs: such detector has the highest discrimination of background events in favour of potential WIMP interactions, which are expected to produce low energy Ar recoils with typical energies of a few tens keV. The basic concept of the detector is the measurement of both the scintillation and the ionization produced by particle interactions inside a liquid argon sensitive volume. Two simultaneous criteria can be applied to select Ar recoils eventually produced by WIMPs: i) Prompt scintillation versus ionization. The prompt scintillation light produced by a particle interacting in the liquid argon phase is detected by PMs. The ionization electrons are extracted from the liquid into the gas and accelerated by an appropriate electric field to produce a proportional (high gain), secondary light pulse seen by the same PMs. The pulse ratio S2/S1 of secondary light S2 (from drift time-delayed ionization) over prompt scintillation light S1 is strongly dependent from columnar recombination of the ionising tracks: therefore nuclear recoils produce typical signals with pulse ratio S2/S1 about 60 times lower than electrons. ii) Pulse shape discrimination of primary scintillation: the primary light is emitted with two components with very large difference in decay times (fast 7 ns, and slow 1.8 μs). The relative amount of the slow component strongly depends from the interacting particle, being around 0.7 for electrons and. 0.1 for heavy charged paricles. The WARP liquid argon detector under construction has a sensitive volume of 100 liters. The goal scintillation yield is of the order of 1 collected photoelectron per keV and the detection threshold for the WIMPs 30 keV. A detailed description of the 100 liters detector can be find in reference [1]. 1 INFN and Dept. of Physics University of Pavia: P. Benetti, E. Calligarich, M. Cambiaghi, C. De Vecchi, R. Dolfini, L. Grandi, A. Menegolli, C. Montanari, M. Prata, A. Rappoldi, G.L. Raselli, M. Roncadelli, M. Rossella, C. Rubbia (Spokesperson), C. Vignoli. INFN and Dept. of Physics University of Napoli "Federico II": F. Carbonara, A.G. Cocco, G. Fiorillo, G. Mangano, R. Santorelli. INFN Laboratori Nazionali del Gran Sasso and University of L'Aquila: F. Cavanna, N. Ferrari, O. Palamara,. L. Pandola. Princeton University, Physics Department: F. Calaprice, C. Galbiati, Y. Zhao. Institute of Nuclear Physics, Krakow : A. Szelc. Figure 1. Energy spectrum observed with the WARP 2.3 liters prototype in the LNGS underground laboratory inside a 10 cm thick Pb shielding. The overlapped red histogram is the expected (montecarlo-simulated) background by interactions of environmental gamma rays. The residual events below 650 keV are produced by Ar and Kr contaminations inside the liquid Argon. Figure 2. Residual energy spectrum after subtraction of the estimated background from environmental gamma rays. The residual spectrum (upper blue curve) is perfectly fitted by the sum of the beta spectra of Ar (green curve, end-point 565 keV, rate 1.1 Bq/litre) and Kr (red curve, end-point 687 keV, rate 0.5 Bq/litre). The vertical scale is expressed in counts/sec/keV. 2. The WARP 2.3 liters prototype detector In order to perfect the detection method, a 2.3 liters prototype detector is in operation at Laboratori Nazionali del Gran Sasso since February 2005. The detector has been equipped, in subsequent phases, with 2'' and 3'' PMs made of low background materials for an onsite detailed study of the backgrounds. The structure is a down-scaled version of the 100 liters detector, with field-shaping electrodes and gas to liquid extraction and acceleration grids. The chamber is filled with ultra-purified argon in order to allow for long drift times of free electrons. Purity is maintained stable by means of continuous argon recirculation. 2.1.1. Study of the β and γ detector backgrounds. The overall background of the 2.3 litres prototype installed underground inside a 10 cm thick Pb shielding has been carefully measured and identified. The total trigger rate above a threshold of 30 keV is about 5 Hz. From a detailed study of the energy spectrum shape (Figure 1) it is shown that about 2 Hz are produced by gamma ray interactions from radioactivity of materials surrounding the sensitive volume; the remaining 3 Hz are produced by the β decays of Kr and Ar dissolved in the liquid argon. In particular, the specific activity of Ar was found to be 1.1 ± 0.4 Bq/litre of liquid Argon, in very good agreement with ref. [2]. We notice that no particular care in the selection of materials was adopted, since in this test phase the background itself helps in the identification of the rejection power. Most of the backgrounds will be strongly reduced in the 100 litres setup. Figure 3. R-like events recorded with the 2.3 liters chamber during 13.4 days of live time in june 2005. The plot shows the primary signal energy (in keV) along the drift time, expressed in μs. The fiducial volume is defined by drift times between 10 and 35 microseconds. Figure 4. Energy distribution of R-like events inside the cathode (upper plot), and inside the fiducial volume (lower plot). The red histogram in the lower plot is the result of a simulation of the expected signal from environmental neutrons in the underground area. 2.1.2. Analysis of Recoil-like events. Data recorded during 13.4 days of live time in a run done in june 2005 have been analyzed looking for recoil-like events by applying the two selection criteria described in section 1. About 6.5 millions events have been processed. The spatial and energy distribution of the 580 selected R-like events (see Figure 3) suggests the following origin for the signals: i) R-like events in the cathode region are mostly induced by decays of Rn daughters. Rn is introduced in the chamber during the filling together with the Ar: being electrically neutral it is uniformly distributed inside the chamber. Daughter nuclei, produced into an ionized state, are drifted to the cathode by the electric field, where they stick. Subsequent decays may end up: (a) with the heavy ion entering the cathode and the α or β travelling in the LAr; (b) with the heavy ion travelling in the LAr and producing the observed R-like signal. The two peaks observed in the energy spectrum (Figure 4, upper plot) are coherently explained by the nuclear recoils from α decays Po Pb (ER=110 keV) and Po Bi (ER=144 keV), assuming a light yield of 0.7 photoelectrons/keV. ii) R-like events inside the fiducial volume are induced by environmental neutrons. Both the event rate and the shape of the energy spectrum (Figure 4, lower plot) are compatible with the expected interactions induced by environmental neutrons inside the underground area (represented by the red histogram). The WARP 2.3 liters chamber in operation at LNGS proofs that the double discrimination technique is effective for separation of recoil events. The first results of the 2.3 liters test (with no neutron shielding) show that the observed background is understood, and that recoil-like signals are compatible with the expected neutron background in the underground area. References [1] WARP proposal, available online at http://warp.pv.infn.it/proposal.pdf [2] H.H. Loosli and H. Oeschger, Earth and Plan. Sci. Lett. 7 (1969) 6

Simulations and measurements of beam loss patterns at the CERN Large Hadron Collider

The CERN Large Hadron Collider (LHC) is designed to collide proton beams of unprecedented energy, in order to extend the frontiers of high-energy particle physics. During the first very successful running period in 2010-2013, the LHC was routinely storing protons at 3.5-4 TeV with a total beam energy of up to 146 MJ, and even higher stored energies are foreseen in the future. This puts extraordinary demands on the control of beam losses. An uncontrolled loss of even a tiny fraction of the beam could cause a superconducting magnet to undergo a transition into a normal-conducting state, or in the worst case cause material damage. Hence a multistage collimation system has been installed in order to safely intercept high-amplitude beam protons before they are lost elsewhere. To guarantee adequate protection from the collimators, a detailed theoretical understanding is needed. This article presents results of numerical simulations of the distribution of beam losses around the LHC that have leaked out of the collimation system. The studies include tracking of protons through the fields of more than 5000 magnets in the 27 km LHC ring over hundreds of revolutions, and Monte Carlo simulations of particle-matter interactions both in collimators and machine elements being hit by escaping particles. The simulation results agree typically within a factor 2 with measurements of beam loss distributions from the previous LHC run. Considering the complex simulation, which must account for a very large number of unknown imperfections, and in view of the total losses around the ring spanning over 7 orders of magnitude, we consider this an excellent agreement. Our results give confidence in the simulation tools, which are used also for the design of future accelerators.peer-reviewe

Investigation of Gamma-aminobutyric acid (GABA) A receptors genes and migraine susceptibility

Background Migraine is a neurological disorder characterized by recurrent attacks of severe headache, affecting around 12% of Caucasian populations. It is well known that migraine has a strong genetic component, although the number and type of genes involved is still unclear. Prior linkage studies have reported mapping of a migraine gene to chromosome Xq 24–28, a region containing a cluster of genes for GABA A receptors (GABRE, GABRA3, GABRQ), which are potential candidate genes for migraine. The GABA neurotransmitter has been implicated in migraine pathophysiology previously; however its exact role has not yet been established, although GABA receptors agonists have been the target of therapeutic developments. The aim of the present research is to investigate the role of the potential candidate genes reported on chromosome Xq 24–28 region in migraine susceptibility. In this study, we have focused on the subunit GABA A receptors type ε (GABRE) and type θ (GABRQ) genes and their involvement in migraine. Methods We have performed an association analysis in a large population of case-controls (275 unrelated Caucasian migraineurs versus 275 controls) examining a set of 3 single nucleotide polymorphisms (SNPs) in the coding region (exons 3, 5 and 9) of the GABRE gene and also the I478F coding variant of the GABRQ gene. Results Our study did not show any association between the examined SNPs in our test population (P > 0.05). Conclusion Although these particular GABA receptor genes did not show positive association, further studies are necessary to consider the role of other GABA receptor genes in migraine susceptibility

Toxicity of wine effluents and assessment of a depuration system for their control: assay with tadpoles of Rhinella arenarum (BUFONIDAE)

We evaluated the toxicity of the winery effluent and the efficiency of a symbiotic depuration system by means an experiment with Rhinella arenarum tadpoles. The studied effluent was taken from warehouses during the cleaning season. These effluents subsequently subjected to the purification treatment under evaluation. The effluent samples differentiated into two treatment levels: “raw” where the effluent was evaluated with field conditions and “treated” where the effluent was previously filtered with the symbiotic depuration system. The results of the bioassays compared with the physicochemical parameters determined in the effluent samples. The lethal response had a clear-cut correspondence with the effluent quality assessed utilizing physicochemical parameters. In all cases, dilution of the samples resulted in a significant reduction of their toxicity. It concluded that (a) winery effluents could be harmful to tadpoles of R. arenarum, (b) the symbiotic purification system used to treat wine effluents it would produce a significant reduction in the contaminant levels of the effluent. However, this reduction in contaminant levels does not provide sufficient safety for the release of the effluents into the environment.Fil: Navas Romero, Ana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; ArgentinaFil: Herrera Moratta, Mario Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; ArgentinaFil: Rodríguez, María Rosa. Universidad Nacional de San Juan. Facultad de Ingeniería; ArgentinaFil: Quiroga, Lorena Beatriz. Universidad Nacional de San Juan. Facultad de Filosofía, Humanidades y Artes. Instituto de Ciencias Básicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Echegaray, Marcelo Eduardo. Universidad Nacional de San Juan. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Sanabria, Eduardo Alfredo. Universidad Nacional de San Juan. Facultad de Filosofía, Humanidades y Artes. Instituto de Ciencias Básicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentin

The NOMAD experiment at the CERN SPS

The NOMAD experiment is a short base-line search for $\nu_{\mu}\rightarrow \nu_{\tau}$ oscillations in the CERN neutrino beam. The $\nu_{\tau}$'s are searched for through their charged-current interactions followed by the observation of the resulting $\tau^{-}$ through its electronic, muonic or hadronic decays. These decays are recognized using kinematical criteria necessitating the use of a light target which enables the reconstruction of individual particles produced in the neutrino interactions. This paper describes the various components of the NOMAD detector: the target and muon drift chambers, the electromagnetic and hadronic calorimeters, the preshower and transition radiation detectors, and the veto and trigger scintillation counters. The beam and data acquisition system are also described. The quality of the reconstruction of individual particles is demonstrated through the ability of NOMAD to observe K$^0_{\rm s}$'s, $\Lambda^0$'s and $\pi^0$'s. Finally, the observation of $\tau^{-}$ through its electronic decay being one of the most promising channels in the search, the identification of electrons in NOMAD is discussed

An expanded evaluation of protein function prediction methods shows an improvement in accuracy

Background: A major bottleneck in our understanding of the molecular underpinnings of life is the assignment of function to proteins. While molecular experiments provide the most reliable annotation of proteins, their relatively low throughput and restricted purview have led to an increasing role for computational function prediction. However, assessing methods for protein function prediction and tracking progress in the field remain challenging. Results: We conducted the second critical assessment of functional annotation (CAFA), a timed challenge to assess computational methods that automatically assign protein function. We evaluated 126 methods from 56 research groups for their ability to predict biological functions using Gene Ontology and gene-disease associations using Human Phenotype Ontology on a set of 3681 proteins from 18 species. CAFA2 featured expanded analysis compared with CAFA1, with regards to data set size, variety, and assessment metrics. To review progress in the field, the analysis compared the best methods from CAFA1 to those of CAFA2. Conclusions: The top-performing methods in CAFA2 outperformed those from CAFA1. This increased accuracy can be attributed to a combination of the growing number of experimental annotations and improved methods for function prediction. The assessment also revealed that the definition of top-performing algorithms is ontology specific, that different performance metrics can be used to probe the nature of accurate predictions, and the relative diversity of predictions in the biological process and human phenotype ontologies. While there was methodological improvement between CAFA1 and CAFA2, the interpretation of results and usefulness of individual methods remain context-dependent. Keywords: Protein function prediction, Disease gene prioritizationpublishedVersio

An Expanded Evaluation of Protein Function Prediction Methods Shows an Improvement In Accuracy

Background: A major bottleneck in our understanding of the molecular underpinnings of life is the assignment of function to proteins. While molecular experiments provide the most reliable annotation of proteins, their relatively low throughput and restricted purview have led to an increasing role for computational function prediction. However, assessing methods for protein function prediction and tracking progress in the field remain challenging. Results: We conducted the second critical assessment of functional annotation (CAFA), a timed challenge to assess computational methods that automatically assign protein function. We evaluated 126 methods from 56 research groups for their ability to predict biological functions using Gene Ontology and gene-disease associations using Human Phenotype Ontology on a set of 3681 proteins from 18 species. CAFA2 featured expanded analysis compared with CAFA1, with regards to data set size, variety, and assessment metrics. To review progress in the field, the analysis compared the best methods from CAFA1 to those of CAFA2. Conclusions: The top-performing methods in CAFA2 outperformed those from CAFA1. This increased accuracy can be attributed to a combination of the growing number of experimental annotations and improved methods for function prediction. The assessment also revealed that the definition of top-performing algorithms is ontology specific, that different performance metrics can be used to probe the nature of accurate predictions, and the relative diversity of predictions in the biological process and human phenotype ontologies. While there was methodological improvement between CAFA1 and CAFA2, the interpretation of results and usefulness of individual methods remain context-dependent