Alignment Strategy for the ATLAS Tracker

ATLAS is a general purpose spectrometer in preparation to take data on the Large Hadron Collider at CERN. It will start its operation in autumn 2007. Charged particle tracking is realized by the Inner Detector. ID consists of two silicon subsystems: Pixel Detector and Semiconductor Tracker complemented by straw proportional gas chambers. In order to exploit the excellent intrinsic resolution of the precision tracking devices a high accuracy alignment is required. In this report the strategy to align silicon detectors of the ATLAS ID will be reviewed together with the current status of preparation

Alignement strategy for the Inner Detector of ATLAS

002704675 ATLAS is a general-purpose spectrometer in preparation for taking data at the Large Hadron Collider at CERN. It will start operation in autumn 2007. Charged particle tracking is realized by the Inner Detector. The Inner Detector consists of two silicon subsystems: a Pixel Detector and a Semiconductor Tracker complemented by straw proportional gas chambers. In order to exploit the excellent intrinsic resolution of the precision tracking devices high accuracy alignment is required. In this report the strategy to align the sub-detectors of the ATLAS Inner Detector is reviewed, together with the current status of preparation. Both track-based and hardware alignment methods are presented

Alignment strategy for the Inner Detector of ATLAS

ATLAS is a general purpose spectrometer in preparation to take data on the Large Hadron Collider at CERN. It will start its operation in autumn 2007. Charged particle tracking is realized by the Inner Detector. ID consists of two silicon subsystems: Pixel Detector and Semiconductor Tracker complemented by straw proportional gas chambers. In order to exploit the excellent intrinsic resolution of the precision tracking devices a high accuracy alignment is required. In this report the strategy to align sub-detectors of the ATLAS ID is reviewed together with the current status of preparation. Both track-based and hardware alignment methods are presented

Least Squares Approach to the Alignment of the Generic High Precision Tracking System

A least squares method to solve a generic alignment problem of high granularity tracking system is presented. The formalism takes advantage of the assumption that the derived corrections are small and consequently uses the first order linear expansion throughout. The algorithm consists of analytical linear expansion allowing for multiple nested fits. E.g. imposing a common vertex for groups of particle tracks is of particular interest. We present a consistent and complete recipe to impose constraints on any set of either implicit or explicit parameters. The baseline solution to the alignment problem is equivalent to the one described in [1]. The latter was derived using purely algebraic methods to reduce the initial large system of linear equations arising from separate fits of tracks and alignment parameters. The method presented here benefits from wider range of applications including problems with implicit vertex fit, physics constraints on track parameters, use of external information to constrain the geometry, etc. The complete formalism is given in [2]. The method has been applied to the full simulation of the ATLAS silicon tracking system. The ultimate goal is to determine ~35,000 degrees of freedom. We present a limited scale exercise exploring various aspects of the solution

Searches for Supersymmetry in ATLAS

Slides for an invited talk at the Epiphany Conference 2010

RNA extraction, probe preparation, and competitive hybridization for transcriptional profiling using Neurospora crassa long-oligomer DNA microarrays

We developed protocols optimized for the performance of experiments assaying genomic gene expression using Neurospora crassa long-oligomer microarrays. We present methods for sample growth and harvesting, total RNA extraction, poly(A)+ mRNA selection, preparation of NH3-Allyl Cy3/Cy5 labeled probes, and microarray hybridization. The quality of the data obtained with these protocols is demonstrated by the comparative transcriptional profiling of basal and apical zones of vegetative growth of N. crassa

Development of a Sandwich ELISA to Measure Exposure to Occupational Cow Hair Allergens

Background: Cow hair and dander are important inducers of occupational allergies in cattle-exposed farmers. To estimate allergen exposure in farming environments, a sensitive enzyme immunoassay was developed to measure cow hair allergens. Methods: A sandwich ELISA was developed using polyclonal rabbit antibodies against a mixture of hair extracts from different cattle breeds. To assess the specificity of the assay, extracts from other mammalian epithelia, mites, molds and grains were tested. To validate the new assay, cow hair allergens were measured in passive airborne dust samples from the stables and homes of farmers. Dust was collected with electrostatic dust fall collectors (EDCs). Results: The sandwich ELISA was found to be very sensitive (detection limit: 0.1 ng/ml) and highly reproducible, demonstrating intra-and interassay coefficients of variation of 4 and 10%, respectively. The assay showed no reactivity with mites, molds and grains, but some cross-reactivity with other mammalian epithelia, with the strongest reaction with goat. Using EDCs for dust sampling, high concentrations of bovine allergens were measured in cow stables (4,760-559,400 mu g/m(2)). In addition, bovine allergens were detected in all areas of cattle farmer dwellings. A large variation was found between individual samples (0.3-900 mu g/m(2)) and significantly higher values were discovered in changing rooms. Conclusion: The ELISA developed for the detection of cow hair proteins is a useful tool for allergen quantification in occupational and home environments. Based on its low detection limit, this test is sensitive enough to detect allergens in passive airborne dust. Copyright (C) 2011 S. Karger AG, Base

The ATLAS SCT grounding and shielding concept and implementation

This paper presents a complete description of Virgo, the French-Italian gravitational wave detector. The detector, built at Cascina, near Pisa (Italy), is a very large Michelson interferometer, with 3 km-long arms. In this paper, following a presentation of the physics requirements, leading to the specifications for the construction of the detector, a detailed description of all its different elements is given. These include civil engineering infrastructures, a huge ultra-high vacuum (UHV) chamber (about 6000 cubic metres), all of the optical components, including high quality mirrors and their seismic isolating suspensions, all of the electronics required to control the interferometer and for signal detection. The expected performances of these different elements are given, leading to an overall sensitivity curve as a function of the incoming gravitational wave frequency. This description represents the detector as built and used in the first data-taking runs. Improvements in different parts have been and continue to be performed, leading to better sensitivities. These will be detailed in a forthcoming paper

HGF Mediates the Anti-inflammatory Effects of PRP on Injured Tendons

Platelet-rich plasma (PRP) containing hepatocyte growth factor (HGF) and other growth factors are widely used in orthopaedic/sports medicine to repair injured tendons. While PRP treatment is reported to decrease pain in patients with tendon injury, the mechanism of this effect is not clear. Tendon pain is often associated with tendon inflammation, and HGF is known to protect tissues from inflammatory damages. Therefore, we hypothesized that HGF in PRP causes the anti-inflammatory effects. To test this hypothesis, we performed in vitro experiments on rabbit tendon cells and in vivo experiments on a mouse Achilles tendon injury model. We found that addition of PRP or HGF decreased gene expression of COX-1, COX-2, and mPGES-1, induced by the treatment of tendon cells in vitro with IL-1β. Further, the treatment of tendon cell cultures with HGF antibodies reduced the suppressive effects of PRP or HGF on IL-1β-induced COX-1, COX-2, and mPGES-1 gene expressions. Treatment with PRP or HGF almost completely blocked the cellular production of PGE2 and the expression of COX proteins. Finally, injection of PRP or HGF into wounded mouse Achilles tendons in vivo decreased PGE2 production in the tendinous tissues. Injection of platelet-poor plasma (PPP) however, did not reduce PGE2 levels in the wounded tendons, but the injection of HGF antibody inhibited the effects of PRP and HGF. Further, injection of PRP or HGF also decreased COX-1 and COX-2 proteins. These results indicate that PRP exerts anti-inflammatory effects on injured tendons through HGF. This study provides basic scientific evidence to support the use of PRP to treat injured tendons because PRP can reduce inflammation and thereby reduce the associated pain caused by high levels of PGE2. © 2013 Zhang et al

Genome-wide association scan meta-analysis identifies three Loci influencing adiposity and fat distribution.

To identify genetic loci influencing central obesity and fat distribution, we performed a meta-analysis of 16 genome-wide association studies (GWAS, N = 38,580) informative for adult waist circumference (WC) and waist-hip ratio (WHR). We selected 26 SNPs for follow-up, for which the evidence of association with measures of central adiposity (WC and/or WHR) was strong and disproportionate to that for overall adiposity or height. Follow-up studies in a maximum of 70,689 individuals identified two loci strongly associated with measures of central adiposity; these map near TFAP2B (WC, P = 1.9x10(-11)) and MSRA (WC, P = 8.9x10(-9)). A third locus, near LYPLAL1, was associated with WHR in women only (P = 2.6x10(-8)). The variants near TFAP2B appear to influence central adiposity through an effect on overall obesity/fat-mass, whereas LYPLAL1 displays a strong female-only association with fat distribution. By focusing on anthropometric measures of central obesity and fat distribution, we have identified three loci implicated in the regulation of human adiposity