4,707 research outputs found
Role of surface microgeometries on electron escape probability and secondary electron yield of metal surfaces
The influence of microgeometries on the Secondary Electron Yield (SEY) of surfaces is investigated. Laser written structures of different aspect ratio (height to width) on a copper surface tuned the SEY of the surface and reduced its value to less than unity. The aspect ratio of microstructures was methodically controlled by varying the laser parameters. The results obtained corroborate a recent theoretical model of SEY reduction as a function of the aspect ratio of microstructures. Nanostructures - which are formed inside the microstructures during the interaction with the laser beam - provided further reduction in SEY comparable to that obtained in the simulation of structures which were coated with an absorptive layer suppressing secondary electron emission
Atmospheric Boundary Layer Height: Inter-Comparison of Different Estimation Approaches Using the Raman Lidar as Benchmark
This work stems from the idea of improving the capability to measure the atmospheric boundary layer height (ABLH) in variable or unstable weather conditions or in the presence of turbulence and precipitation events. A new approach based on the use of rotational and roto-vibrational Raman lidar signals is considered and tested. The traditional gradient approach based on the elastic signals at wavelength 532 nm is also considered. Lidar data collected by the University of Basilicata Raman lidar (BASIL) within the Special Observation Period 1 (SOP 1) in Cardillargues (Ceveninnes-CV supersite) during the Hydrological Cycle in the Mediterranean Experiment (HyMeX) were used. Our attention was specifically focused on the data collected during the period 16-21 October 2012. ABLH estimates from the Raman lidar were compared against other innovative methods, such as the recently established Morphological Image Processing Approach (MIPA) and the temperature gradient technique applied to potential temperature obtained from radio-sounding data. For each considered methodology, a statistical analysis was carried out. In general, the results from the different methodologies are in good agreement. Some deviations have been observed in correspondence with quite unstable weather conditions
Dominant next-to-leading order QCD corrections to Higgs plus three jet production in vector-boson fusion
We present the calculation of the dominant next to leading order QCD
corrections to Higgs boson production in association with three jets via vector
boson fusion in the form of a NLO parton-level Monte Carlo program. QCD
corrections to integrated cross sections are modest, while the shapes of some
kinematical distributions change appreciably at NLO. Scale uncertainties are
shown to be reduced at NLO for the total cross section and for distributions.
We consider a central jet veto at the LHC and analyze the veto probability for
typical vector boson fusion cuts. Scale uncertainties of the veto probability
are sufficiently small at NLO for precise Higgs coupling measurements at the
LHC.Comment: 40 pages, 17 figures, 2 tables, published versio
Hadron beam test of a scintillating fibre tracker system for elastic scattering and luminosity measurement in ATLAS
A scintillating fibre tracker is proposed to measure elastic proton
scattering at very small angles in the ATLAS experiment at CERN. The tracker
will be located in so-called Roman Pot units at a distance of 240 m on each
side of the ATLAS interaction point. An initial validation of the design
choices was achieved in a beam test at DESY in a relatively low energy electron
beam and using slow off-the-shelf electronics. Here we report on the results
from a second beam test experiment carried out at CERN, where new detector
prototypes were tested in a high energy hadron beam, using the first version of
the custom designed front-end electronics. The results show an adequate
tracking performance under conditions which are similar to the situation at the
LHC. In addition, the alignment method using so-called overlap detectors was
studied and shown to have the expected precision.Comment: 12 pages, 8 figures. Submitted to Journal of Instrumentation (JINST
Typical and atypical COVID-19 computed tomography findings
In December 2019 a novel coronavirus, named severe acute respiratory syndrome coronavirus 2 was identified and the disease associated was named coronavirus disease 2019 (COVID-19). Fever, cough, myalgia, fatigue associated to dyspnea represent most common clinical symptoms of the disease. The reference standard for diagnosis of severe acute respiratory syndrome coronavirus 2 infection is real time reverse-transcription polymerase chain reaction test applied on respiratory tract specimens. Despite of lower specificity, chest computed tomography (CT), as reported in manifold scientific studies, showed high sensitivity, therefore it may help in the early detection, management and follow-up of COVID-19 pneumonia. Patients affected by COVID-19 pneumonia usually showed on chest CT some typical features, such as: Bilateral ground glass opacities characterized by multilobe involvement with posterior and peripheral distribution; parenchymal consolidations with or without air bronchogram; interlobular septal thickening; crazy paving pattern, represented by interlobular and intralobular septal thickening surrounded by ground-glass opacities; subsegmental pulmonary vessels enlargement (> 3 mm). Halo sign, reversed halo sign, cavitation and pleural or pericardial effusion represent some of atypical findings of COVID-19 pneumonia. On the other hand lymphadenopathy's and bronchiectasis' frequency is unclear, indeed conflicting data emerged in literature. Radiologists play a key role in recognition of high suspicious findings of COVID-19 on chest CT, both typical and atypical ones. Thus, the aim of this review is to illustrate typical and atypical CT findings of COVID-19
Prevalence and correlates of depressive disorders in people with Type 2 diabetes: results from the International Prevalence and Treatment of Diabetes and Depression (INTERPRET‐DD) study, a collaborative study carried out in 14 countries
Aims
To assess the prevalence and management of depressive disorders in people with Type 2 diabetes in different countries.
Methods
People with diabetes aged 18–65 years and treated in outpatient settings were recruited in 14 countries and underwent a psychiatric interview. Participants completed the Patient Health Questionnaire and the Problem Areas in Diabetes scale. Demographic and medical record data were collected.
Results
A total of 2783 people with Type 2 diabetes (45.3% men, mean duration of diabetes 8.8 years) participated. Overall, 10.6% were diagnosed with current major depressive disorder and 17.0% reported moderate to severe levels of depressive symptomatology (Patient Health Questionnaire scores >9). Multivariable analyses showed that, after controlling for country, current major depressive disorder was significantly associated with gender (women) (PPPPP<0.0001). The proportion of those with either current major depressive disorder or moderate to severe levels of depressive symptomatology who had a diagnosis or any treatment for their depression recorded in their medical records was extremely low and non-existent in many countries (0–29.6%).
Conclusions
Our international study, the largest of this type ever undertaken, shows that people with diabetes frequently have depressive disorders and also significant levels of depressive symptoms. Our findings indicate that the identification and appropriate care for psychological and psychiatric problems is not the norm and suggest a lack of the comprehensive approach to diabetes management that is needed to improve clinical outcomes
The Higgs Working Group: Summary Report (2001)
Report of the Higgs working group for the Workshop `Physics at TeV
Colliders', Les Houches, France, 21 May - 1 June 2001. It contains 7 separate
sections: A. Theoretical Developments B. Higgs Searches at the Tevatron C.
Experimental Observation of an invisible Higgs Boson at LHC D. Search for the
Standard Model Higgs Boson using Vector Boson Fusion at the LHC E. Study of the
MSSM channel at the LHC F. Searching for Higgs Bosons in
Production G. Studies of Charged Higgs Boson Signals for the
Tevatron and the LHCComment: 120 pages, latex, many figures, proceedings of the Workshop `Physics
at TeV Colliders', Les Houches, France, 21 May - 1 June 2001, full Author
list included in paper. Typos corrected, author list and acknowledgements
completed. Convernors: D. Cavalli, A. Djouadi, K. Jakobs, A. Nikitenko, M.
Spira, C.E.M. Wagner, W.-M. Ya
Strategies for the Follow-up of Gravitational Wave Transients at Very High-Energy Gamma Rays with the Cherenkov Telescope Array
With the observation of the first electromagnetic counterpart of Gravitational Wave (GW) transient GW170817, the potential of multimessenger astronomy has been clearly demonstrated. In its full configuration, the Cherenkov Telescope Array (CTA) observatory will be capable of rapidly covering the regions localized by future GW observations with sufficient sensitivity at very high-energy gamma rays. In view of the forthcoming deployment of its first telescopes, we identify some general strategies for GW follow-up that will improve the CTA contribution to multimessenger discoveries
INFN Camera demonstrator for the Cherenkov Telescope Array
The Cherenkov Telescope Array is a world-wide project for a new generation of
ground-based Cherenkov telescopes of the Imaging class with the aim of
exploring the highest energy region of the electromagnetic spectrum. With two
planned arrays, one for each hemisphere, it will guarantee a good sky coverage
in the energy range from a few tens of GeV to hundreds of TeV, with improved
angular resolution and a sensitivity in the TeV energy region better by one
order of magnitude than the currently operating arrays. In order to cover this
wide energy range, three different telescope types are envisaged, with
different mirror sizes and focal plane features. In particular, for the highest
energies a possible design is a dual-mirror Schwarzschild-Couder optical
scheme, with a compact focal plane. A silicon photomultiplier (SiPM) based
camera is being proposed as a solution to match the dimensions of the pixel
(angular size of ~ 0.17 degrees). INFN is developing a camera demonstrator made
by 9 Photo Sensor Modules (PSMs, 64 pixels each, with total coverage 1/4 of the
focal plane) equipped with FBK (Fondazione Bruno Kessler, Italy) Near
UltraViolet High Fill factor SiPMs and Front-End Electronics (FEE) based on a
Target 7 ASIC, a 16 channels fast sampler (up to 2GS/s) with deep buffer,
self-trigger and on-demand digitization capabilities specifically developed for
this purpose. The pixel dimensions of mm lead to a very compact
design with challenging problems of thermal dissipation. A modular structure,
made by copper frames hosting one PSM and the corresponding FEE, has been
conceived, with a water cooling system to keep the required working
temperature. The actual design, the adopted technical solutions and the
achieved results for this demonstrator are presented and discussed.Comment: In Proceedings of the 34th International Cosmic Ray Conference
(ICRC2015), The Hague, The Netherlands. All CTA contributions at
arXiv:1508.0589
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