3,523 research outputs found
Luminosity measurement method for the LHC: The detector requirements studies
Absolute normalisation of the LHC measurements with a precision of O(1%) is
desirable but beyond the reach of the present LHC detectors. This series of
papers proposes and evaluates a measurement method capable to achieve such a
precision target. In our earlier paper we have selected the phase-space region
where the lepton pair production cross section in pp collisions at the LHC can
be controlled with < 1 % precision and is large enough to reach a comparable
statistical accuracy of the absolute luminosity measurement on the day-by-day
basis. In the present one the performance requirements for a dedicated
detector, indispensable to efficiently select events in the proposed
phase-space region, are discussed.Comment: 26 pages, 13 figure
Morphological predictors of sleep apnoea severity
Background: Obstructive sleep apnoea (OSA) does not always depend on obesity but on a certain morphological configuration. The study objective was to verify a hypothesis about a relation between anthropometric features and OSA occurrence and severity.
Materials and methods: The study involved 138 patients, who had reported in Department and Clinic of Otolaryngology, Warsaw Medical University, due to suspected OSA. Each patient underwent morphological evaluation according to visual analogue scales. The assessment involved nasal septum morphology evaluation according to a 4-grade scale, palate morphology evaluation according to the 4-grade Friedman scale, whereas the facial profile, oropharyngeal isthmus, and the shape of the nasopharynx were assessed according to our own 3-grade scale.
Results: Statistical analysis confirmed the high concordance of the basic polysomnographic parameters with the Friedman scale and the shape of the oropharyngeal isthmus.
Conclusions: 1. The modified Mallampati score as well as evaluation of the shape of the oropharyngeal isthmus demonstrated high concordance with the basic polysomnographic parameters. 2. The neck circumference is a significant predictor of the apnoea-hypopnoea index value in males suffering from the OSA syndrom
Luminosity Measurement Method for LHC: The theoretical precision and the experimental challenges
This is the first of the series of papers which present a precision method of the day-by-day monitoring of the absolute LHC luminosity. The method is based on the measurement of the rate of coplanar lepton pairs produced in peripheral collisions of the beams' particles. In the present paper we evaluate the modeling precision of the lepton pair production processes in proton-proton collisions, optimize the measurement region to achieve better than 1% accuracy of the predicted rates, and discuss the experimental challenges to filter out the luminosity monitoring lepton pairs at LHC
Z-boson as "the standard candle" for high precision W-boson physics at LHC
In this paper we propose a strategy for measuring the inclusive W-boson
production processes at LHC. This strategy exploits simultaneously the unique
flexibility of the LHC collider in running variable beam particle species at
variable beam energies, and the configuration flexibility of the LHC detectors.
We propose their concrete settings for a precision measurement of the Standard
Model parameters. These dedicated settings optimise the use of the Z boson and
Drell-Yan pair production processes as ``the standard reference candles''. The
presented strategy allows to factorise and to directly measure those of the QCD
effects which affect differently the W and Z production processes. It reduces
to a level of 10^{-4} the impact of uncertainties in the partonic distribution
functions (PDFs) and in the transverse momentum of the quarks on the
measurement precision. Last but not the least, it reduces by a factor of 10 an
impact of systematic measurement errors, such as the energy scale and the
measurement resolution, on the W-boson production observables.Comment: 20 pages, 4 figure
Location of the narrowest area of the pharynx regarding body mass index and obstructive sleep apnoea severity
Background: Among authors studying morphological determinants of the obstructive sleep apnoea (OSA) controversies exist on the location of the narrowest area within the pharynx, critical for development of obstruction. Those disagreements primarily revolve around differences between obese and nonobese OSA patients. Determination whether the location and size of the narrowest area within the pharynx differentiates the obese and nonobese OSA patients.
Materials and methods: A population of 55 subjects was investigated after being diagnosed with OSA in the Polysomnography Laboratory of the Department and Clinic of Otolaryngology in the Medical University of Warsaw, Poland. Additionally a head computed tomography (CT) was performed in all the subjects. The CT images were used to do several crucial measurements which described the geometry of the facial skeleton as well as soft tissues of the head. The obtained results were correlated with apnoea-hypopnoea index (AHI) and body mass index (BMI) values. The data were statistically analysed.
Results: The distance between the hard palate and posterior pharyngeal wall parallel to the horizontal plane as well as the shortest distance between the soft palate and posterior pharyngeal wall significantly differentiated patients in the subgroups by AHI but not by BMI.
Conclusions: Pharyngeal obstruction at the level of the hard and soft palate differentiates patients with severe OSA from patients with mild and moderate OSA regardless of BMI
Luminosity Measurement Method for the LHC: Event Selection and Absolute Luminosity Determination
Absolute normalisation of the LHC measurements with O(1%) precision and their
relative normalisation, for the data collected at variable centre-of-mass
energies, or for variable beam particle species, with O(0.1%) precision is
crucial for the LHC experimental programme but presently beyond the reach for
the general purpose LHC detectors. This paper is the third in the series of
papers presenting the measurement method capable to achieve such a goal.Comment: 31 pages, 15 figure
Extension as a Multilevel Bridging Organization: Supporting Networked Environmental Governance
Governmental and nongovernmental actors at different spatial and jurisdictional levels have information that can benefit natural resources management; however, barriers in communication and organizational culture often prevent information sharing and joint endeavors. Bridging entities, such as task forces or working groups, bring together potential stakeholders to pool expertise and stimulate shared learning. Using a network survey, interview data, and meeting minutes, we constructed a case study of task forces convened to stimulate management of the emerald ash borer, an invasive wood-boring beetle. We found that coordinated action among university and county Extension catalyzed bridging through visionary program design and network positioning
The suboptimal structures find the optimal RNAs: homology search for bacterial non-coding RNAs using suboptimal RNA structures
Non-coding RNAs (ncRNAs) are regulatory molecules encoded in the intergenic or intragenic regions of the genome. In prokaryotes, biocomputational identification of homologs of known ncRNAs in other species often fails due to weakly evolutionarily conserved sequences, structures, synteny and genome localization, except in the case of evolutionarily closely related species. To eliminate results from weak conservation, we focused on RNA structure, which is the most conserved ncRNA property. Analysis of the structure of one of the few well-studied bacterial ncRNAs, 6S RNA, demonstrated that unlike optimal and consensus structures, suboptimal structures are capable of capturing RNA homology even in divergent bacterial species. A computational procedure for the identification of homologous ncRNAs using suboptimal structures was created. The suggested procedure was applied to strongly divergent bacterial species and was capable of identifying homologous ncRNAs
Measurement of MW+ - MW- at LHC
This paper is the second of the series of papers proposing dedicated
strategies for precision measurements of the Standard Model parameters at the
LHC. The common feature of these strategies is their robustness with respect to
the systematic measurement and modeling error sources. Their impact on the
precision of the measured parameters is reduced using dedicated observables and
dedicated measurement procedures which exploit flexibilities of the collider
and detector running modes. In the present paper we focus our attention on the
measurement of the charge asymmetry of the W-boson mass. This measurement is of
primordial importance for the LHC experimental program, both as a direct test
of the charge-sign-independent coupling of the W-bosons to the matter particles
and as a necessary first step towards the precision measurement of the
charge-averaged W-boson mass. We propose and evaluate the LHC-specific strategy
to measure the mass difference between the positively and negatively charged
W-bosons, MW+ - MW-. We show that its present precision can be improved at the
LHC by a factor of 20. We argue that such a precision is beyond the reach of
the standard measurement and calibration methods imported to the LHC from the
Tevatron program.Comment: 39 pages, 8 figure
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