849 research outputs found
Distributed Computing Grid Experiences in CMS
The CMS experiment is currently developing a computing system capable of serving, processing and archiving the large number of events that will be generated when the CMS detector starts taking data. During 2004 CMS undertook a large scale data challenge to demonstrate the ability of the CMS computing system to cope with a sustained data-taking rate equivalent to 25% of startup rate. Its goals were: to run CMS event reconstruction at CERN for a sustained period at 25 Hz input rate; to distribute the data to several regional centers; and enable data access at those centers for analysis. Grid middleware was utilized to help complete all aspects of the challenge. To continue to provide scalable access from anywhere in the world to the data, CMS is developing a layer of software that uses Grid tools to gain access to data and resources, and that aims to provide physicists with a user friendly interface for submitting their analysis jobs. This paper describes the data challenge experience with Grid infrastructure and the current development of the CMS analysis system
Fragmentation of relativistic nuclei in peripheral interactions in nuclear track emulsion
The technique of nuclear track emulsions is used to explore the fragmentation
of light relativistic nuclei down to the most peripheral interactions - nuclear
"white" stars. A complete pattern of therelativistic dissociation of a B
nucleus with target fragment accompaniment is presented. Relativistic
dissociation Be is explored using significant statistics and
a relative contribution of Be decays from 0 and 2 states is
established. Target fragment accompaniments are shown for relativistic
fragmentation N3He+H and Ne5He. The leading role of the
electromagnetic dissociation on heavy nuclei with respect to break-ups on
target protons is demonstrated in all these cases. It is possible to conclude
that the peripheral dissociation of relativistic nuclei in nuclear track
emulsion is a unique tool to study many-body systems composed of lightest
nuclei and nucleons in the energy scale relevant for nuclear astrophysics.Comment: 15 pages, 4 figures, 4 tables, conference: Relativistic nuclear
physics: from Nuclotron to LHC energies, Kiev, June 18-22, 200
Topology of "white" stars in relativistic fragmentation of light nuclei
In the present paper, experimental observations of the multifragmentation
processes of light relativistic nuclei carried out by means of emulsions are
reviewed. Events of the type of "white" stars in which the dissociation of
relativistic nuclei is not accompanied by the production of mesons and the
target-nucleus fragments are considered.
A distinctive feature of the charge topology in the dissociation of the Ne,
Mg, Si, and S nuclei is an almost total suppression of the binary splitting of
nuclei to fragments with charges higher than 2. The growth of the nuclear
fragmentation degree is revealed in an increase in the multiplicity of singly
and doubly charged fragments with decreasing charge of the non-excited part of
the fragmenting nucleus.
The processes of dissociation of stable Li, Be, B, C, N, and O isotopes to
charged fragments were used to study special features of the formation of
systems consisting of the lightest , d, and t nuclei. Clustering in
form of the He nucleus can be detected in "white" stars via the
dissociation of neutron-deficient Be, B, C, and N isotopes.Comment: 20 pages, 3 figures, 9 tables, conference: Conference on Physics of
Fundamental Interactions, Moscow, Russia, 1-5 Mar 2004.(Author's translation
Influence of assembly and operation asymmetries on Wendelstein 7-X magnetic field perturbations
Wendelstein 7-X is a modular advanced stellarator realizing a 5-period Helias configuration. An important part of the planned operational plasma scenarios is characterised by a rotational transform ι/2π =1 at the plasma boundary. Such configurations are very sensitive to symmetry breaking perturbations, resonant with the value of the rotational transform at the boundary and violating the toroidal periodicity of the magnetic field. The most critical consequences of magnetic field perturbations are modifications of the island topology, which can result in uneven loads on the divertor targets and affect the plasma performance. In this paper the level of magnetic field perturbations due to possible symmetry distortions under electromagnetic loads is estimated and comparative analysis with previously investigated magnetic field errors is presented
Whole exome sequencing links dental tumor to an autosomal-dominant mutation in ANO5 gene associated with gnathodiaphyseal dysplasia and muscle dystrophies
Tumors of the jaws may represent different human disorders and frequently associate with pathologic bone fractures. In this report, we analyzed two affected siblings from a family of Russian origin, with a history of dental tumors of the jaws, in correspondence to original clinical diagnosis of cementoma consistent with gigantiform cementoma (GC, OMIM: 137575). Whole exome sequencing revealed the heterozygous missense mutation c.1067G \u3e A (p.Cys356Tyr) in ANO5 gene in these patients. To date, autosomal-dominant mutations have been described in the ANO5 gene for gnathodiaphyseal dysplasia (GDD, OMIM: 166260), and multiple recessive mutations have been described in the gene for muscle dystrophies (OMIM: 613319, 611307); the same amino acid (Cys) at the position 356 is mutated in GDD. These genetic data and similar clinical phenotypes demonstrate that the GC and GDD likely represent the same type of bone pathology. Our data illustrate the significance of mutations in single amino-acid position for particular bone tissue pathology. Modifying role of genetic variations in another gene on the severity of the monogenic trait pathology is also suggested. Finally, we propose the model explaining the tissue-specific manifestation of clinically distant bone and muscle diseases linked to mutations in one gene
Changes of photosynthesis and carbon metabolism in Typha angustifolia L grown in conditions of nitrate nitrogen overload
Nitrates may induce alterations in NO-signaling system and change photosynthesisin plants. Significant reduction of 14CO2 fixation was noted at concentration of 3.96mM NaNO3 in an aquatic macrophyte (Typha angustifolia L.). Assimilation of 14CO2 seven days after the introduction of nitrates did not differ between control and experimental samples. There were changes in distribution of 14C among products of 4CO2 fixation 4 h after NaNO3 addition, resulting in increased sugar radioactivity in experimental plants. It was suggested that the observed changes may have regulatory importance
NA61/SHINE facility at the CERN SPS: beams and detector system
NA61/SHINE (SPS Heavy Ion and Neutrino Experiment) is a multi-purpose
experimental facility to study hadron production in hadron-proton,
hadron-nucleus and nucleus-nucleus collisions at the CERN Super Proton
Synchrotron. It recorded the first physics data with hadron beams in 2009 and
with ion beams (secondary 7Be beams) in 2011.
NA61/SHINE has greatly profited from the long development of the CERN proton
and ion sources and the accelerator chain as well as the H2 beamline of the
CERN North Area. The latter has recently been modified to also serve as a
fragment separator as needed to produce the Be beams for NA61/SHINE. Numerous
components of the NA61/SHINE set-up were inherited from its predecessors, in
particular, the last one, the NA49 experiment. Important new detectors and
upgrades of the legacy equipment were introduced by the NA61/SHINE
Collaboration.
This paper describes the state of the NA61/SHINE facility - the beams and the
detector system - before the CERN Long Shutdown I, which started in March 2013
The in vitro influence of different factors on the indicators of human ejaculate
The paper presents the results of investigations dealing with the impact of experimental exposures (to chemical substances and electromagnetic radiation) on human sperm. The radiation is shown to suppress sperm motility. High hydrogen peroxide concentrations and ejaculate cryopreservation have also a negative effect on sperm motility and viability. Low hydrogen peroxide levels cause the opposite effect on sperm motility. The use of some regulatory mechanisms also yields positive results. Antioxidants increase the number of mobile sex cells in an experiment. Clinical observations using antioxidants support the results of laboratory tests
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