930 research outputs found

    Parallel Computing Studies for the Alignment of the ATLAS Silicon Tracker

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    The silicon system of the ATLAS Inner Detector consists of about 6000 modules in its Semiconductor Tracker and Pixel Detector. Therefore, the offline global fit alignment algorithm has to deal with solving a problem of up to 36000 degrees of freedom.32-bit single-CPU platforms were foreseen to be unable to handle such large-size operations needed by the algorithm. The proposed solution is to utilize a Beowulfcluster with a 64-bit architecture. We have performed the initial studies on performance of such a system using SCARF RAL cluster, compared with earlier predictions, obtained the first promising results on parallel computing for the ATLAS tracker alignment. After a brief introduction with the motivation, we will describe the hardware and software used and present the results of the studies, using also examples from the ATLAS simulated data

    Fourth Family Neutrinos and the Higgs Boson

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    We evaluate the LHC discovery potential for the fourth family Standard Model neutrinos in the process pp→Z/h→ν4νˉ4→WμWμpp\to Z/h\to\nu_{4}{\bar{\nu}_{4}}\to W\mu W\mu. We show that, depending on their masses, the simultaneous discovery of both the Higgs boson and the heavy neutrinos is probable at early stages of LHC operation. Results are presented for both Majorana and Dirac type fourth family neutrinos.Comment: 12 pages, uses axodraw.sty, v2: includes typo fixes, improved analysis, v4: minor modifications in response to the JHEP refere

    Study of a twisted ATLAS SCT Barrel deformation as revealed by a photogrammetric survey

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    A photogrammetry survey on the SCT barrels was performed as an engineering check on the structure of the ATLAS Semiconductor Tracker (SCT) shortly after construction. Analysis of the data obtained revealed small scale elliptical deformation as well as a twist of the structure. The results of the survey are presented as well as interpolation of the measured targets to the module positions and a comparison with track based alignment measurements

    Ehrlich ascites carcinoma

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    Experimental tumors have great importance in modeling, and Ehrlich ascites carcinoma (EAC) is one of the commonest tumors. EAC is referred to as an undifferentiated carcinoma and is originally hyperdiploid, has high transplantable capability, no-regression, rapid proliferation, shorter life span, 100% malignancy and also does not have tumor-specific transplantation antigen (TSTA). Frequently, tumor virulence increases via repetitious passages, while the proliferating rate of such tumors increases gradually. However, the differentiation gradually disappears, while the cells get free growth control mechanisms, gain hetero-transplantability and in the end, they are converted to the ascites’ form. EAC resembles human tumors which are the most sensitive to chemotherapy due to the fact that they are undifferentiated and that they have a rapid growth rate. The ideal drug being ineffective or minimally effective for normal cells have been focused on, and at this point, the usage of natural sources as an alternative cancer therapy is thought to have a great value for cancer control and programs’ destruction.Key words: carcinoma, transplantabilit

    Low Scale Gravity Signatures in ATLAS

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    The ATLAS detector may reveal in the LHC collisions signatures of extra dimensional models which predict quantum gravity at the TeV scale. One of the most dramatic consequences of such models is the copious production of micro blackholes. Micro blackholes can yield distinct signatures with large multiplicity and large energy release in the ATLAS detector. Extra dimensional models also predict the existence of Kaluza-Klein partners of SM gauge bosons, such as the excited graviton and gluon. These particles can be searched for in their two-body decays. The emerging final state particles are highly energetic, thus requiring novel reconstruction techniques, in particular in the heavy quark (t, b) channels. I will summarize the current status of the low scale gravity studies in ATLAS with example signatures

    The role of stethoscopes in the transmission of hospital infections

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    Stethoscopes are one of the most commonly used medical devices and have been reported to be potential sources of hospital acquired infections. In this study, we aimed to find out the bacterial contamination of stethoscopes used by health-care staff. Swab samples were taken from the surface of the diaphragm of the stethoscopes used by health personnel in four hospitals including three secondline and one third-line health care institution in Turkey. The samples were inoculated onto bacteriological and mycological media. For identification of the microorganisms, conventional methods and Vitek2 (Biomérieux) were performed. Swab samples were taken from 121 stethoscopes. We found bacterial and fungal contamination on 92 (76%) of the stethoscopes. 15 out 90 (16.3%) had potential pathogens including methicillin susceptible Staphylococcus aureus (5), methicillin resistance Staphylococcus aureus (4), Escherichia coli (3), Acinetobacter baumannii, Acinetobacter haemolyticus and Enterococcus spp. Of the 121 health-care persons, only 61 regularly cleaned their stethoscopes by various disinfectants. The statistical difference between the two groups in terms of pathogen and microorganism isolation was not determined (p>0.05). Although stethoscopes are uncritical medical devices, they could contain pathogen microorganisms and they might be a potential source of hospital acquired infections.Key words: Stethoscopes, hospital infections, Staphylococcus aureus

    Computational Fluid Dynamic Studies of Vortex Amplifier Design for the Nuclear Industry—I. Steady-State Conditions

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    In this study the effects of changes to the geometry of a vortex amplifier are investigated using computational fluid dynamics (CFD) techniques, in the context of glovebox operations for the nuclear industry. These investigations were required because of anomalous behavior identified when, for operational reasons, a long-established vortex amplifier design was reduced in scale. The aims were (i) to simulate both the anomalous back-flow into the glovebox through the vortex amplifier supply ports, and the precessing vortex core in the amplifier outlet, then (ii) to determine which of the various simulated geometries would best alleviate the supply port back-flow anomaly. Various changes to the geometry of the vortex amplifier were proposed; smoke and air tests were then used to identify a subset of these geometries for subsequent simulation using CFD techniques. Having verified the mesh resolution was sufficient to reproduce the required effects, the code was then validated by comparing the results of the steady-state simulations with the experimental data. The problem is challenging in terms of the range of geometrical and dynamic scales encountered, with consequent impact on mesh quality and turbulence modeling. The anomalous nonaxisymmetric reverse flow in the supply ports of the vortex amplifier has been captured and the mixing in both the chamber and the precessing vortex core has also been successfully reproduced. Finally, by simulating changes to the supply ports that could not be reproduced experimentally at an equivalent cost, the geometry most likely to alleviate the back-flow anomaly has been identified

    Investigation of nasal colonization of health care workers by methicillin-resistant Staphylococcus aureus with using new generation real-time PCR assay: Discussing of risks

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    Methicillin-resistant Staphylococcus aureus (MRSA) is a nasal infectious pathogen which is becoming of significant importance year by year. Mortality, morbidity and treatment costs of MRSA infectionshave all increased. The most effective preventative tool is rapid confirmation of MRSA existence, followed by efficient execution of the required infection control measures. This study was performedwith the aim of evaluating MRSA colonization in health care staff from intensive care units (internal and surgical intensive care units) (ICUs) and how certain risk factors affect their colonization status. The study was conducted prospectively using samples obtained from nasal swabs of health-care staffs working in different missions in the intensive care unit of Gaziantep University Training Hospital in southeast of Turkey. The nasal swab samples were processed using a real-time PCR method platformcalled GeneXpert (Cepheid). Our PCR screen revealed the presence of MRSA in 14 of 98 health-care staffs. Of these 14 health-care staffs carrying nasal MRSA, 10 were male, 8 were assistant health-care personnel and 11 have been working for over one year in the intensive care unit. Our data showed that male gender and an employment during of more than one year served as significant risk factors for nasal MRSA colonization

    A redox-neutral, two-enzyme cascade for the production of malate and gluconate from pyruvate and glucose

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    A triple mutant of NADP(H)-dependent malate dehydrogenase from thermotolerant Thermococcus kodakarensis has an altered cofactor preference for NAD+, as well as improved malate production compared to wildtype malate dehydrogenase. By combining mutant malate dehydrogenase with glucose dehydrogenase from Sulfolobus solfataricus and NAD+/NADH in a closed reaction environment, gluconate and malate could be produced from pyruvate and glucose. After 3 h, the yield of malate was 15.96 mM. These data demonstrate the feasibility of a closed system capable of cofactor regeneration in the production of platform chemicals

    Comparing The Rate of Radiological and Clinical Adjacent Segment Degeneration After Simple Anterior Cervical Discectomy Versus Discectomy Plus Fusion

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    Objective: To evaluate and compare the radiological changes on adjacent mobile segments and clinical findings in patients having undergone single-segment simple anterior cervical discectomy versus discectomy plus intervertebral fusion.Material and Methods: Twenty-five patients were treated with discectomy plus fusion and 20 patients with simple discectomy. Clinical pictures of the patients were evaluated with ODOM criteria before and 1 year after operation, and their improvement rates were calculated. The disc heights of superior and inferior adjacent segments, superior and inferior foramen heights, superior and inferior end plate heights of superior and inferior adjacent segments, new osteophyte development, segmental angulation and loss of cervical lordosis were evaluated on cervical radiographies before and 1 year after operation.Results: Although there were new degenerative findings in adjacent mobile segments in all patients when preoperative and postoperative measurements were compared, these radiological findings did not translate into clinical findings. In the fusion group, radiological degeneration findings were seen more frequently statistically; however, clinical results were not different between the two groups. On the other hand, loss of lordosis was significantly more frequent in the simple discectomy group.Conclusion: Although adding fusion to single-segment anterior cervical discectomy caused more frequent radiological degenerative changes in adjacent segments after 1 year compared to simple discectomy, clinical results were similar. It was thought that longer follow-up was necessary to observe clinical adjacent segment disease that was expected to become more frequent because of excessive mobility due to fusion
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