275 research outputs found
Higgs production in gluon fusion at next-to-next-to-leading order QCD for finite top mass
The inclusive Higgs production cross section from gluon fusion is calculated
through NNLO QCD, including its top quark mass dependence. This is achieved
through a matching of the 1/mtop expansion of the partonic cross sections to
the exact large s-hat limits which are derived from k_T-factorization. The
accuracy of this procedure is estimated to be better than 1% for the hadronic
cross section. The final result is shown to be within 1% of the commonly used
effective theory approach, thus confirming earlier findings.Comment: 28 pages, 14 figure
Comparison of numerical models for Acoustic Emission propagation
Abstract Acoustic Emissions (AE) are at the basis of extremely accurate and reliable monitoring systems. Within the SmartBench project, data regarding structural health of components are gathered in a database in order to make safety integrated, operative and smart. An accurate modelling of wave propagation is a necessary requirement for a proper design of sensor networks as well as for data interpretation. Numerical simulations of the transient behavior of structural systems are well-established in this field but, on the minus side, they are very expensive in terms of computational time and resources. This paper reports different instances of AE propagation through metallic media. Bulk waves and guided waves are both investigated by means of 2D and 3D models and resorting to different software. Obtained results are cross-checked and computational times are compared as well. As a last point, High Performance Computing is applied to the case of waves simulation in order to get a significant reduction of the required computational time
Une méthode pour le prétraitement et le calcul de matrices de crosstalk pour des images couleur issues d'une caméra tri-CCD
- Ce travail s'inscrit comme outil dans le cadre de la reconstruction 3D à l'aide d'une projection de lumière structurée couplée à une caméra 3CCD. Le principe est simple : il faut disposer une caméra 3CCD et un vidéo-projecteur comme un système de stéréovision classique, devant la scène à étudier. L'utilisation d'une lumière structurée lève beaucoup d'ambiguïtés par rapport à un système de stéréovision à deux caméras. Par contre, l'utilisation de la couleur pour coder la projection réduit le champ d'action du système aux objets blancs ou pâles. Pour pouvoir déterminer la couleur en même temps que la reconstruction 3D de l'objet, il faut avoir des images couleurs parfaitement nettoyées. Nous allons donc décrire une méthode de prétraitements des images couleurs issues de la caméra 3CCD utilisée. Les images ainsi traitées peuvent être utilisées dans le modèle couleur que nous suivrons pour remonter aux informations de couleur de l'éclairage structuré pour lever les ambiguïtés de mise en correspondance, ainsi qu 'à la couleur de la scène aux points considérés
Advanced Video-Based Processing for Low-Cost Damage Assessment of Buildings under Seismic Loading in Shaking Table Tests
This paper explores the potential of a low-cost, advanced video-based technique for the assessment of structural damage to buildings caused by seismic loading. A low-cost, high-speed video camera was utilized for the motion magnification processing of footage of a two-story reinforced-concrete frame building subjected to shaking table tests. The damage after seismic loading was estimated by analyzing the dynamic behavior (i.e., modal parameters) and the structural deformations of the building in magnified videos. The results using the motion magnification procedure were compared for validation of the method of the damage assessment obtained through analyses of conventional accelerometric sensors and high-precision optical markers tracked using a passive 3D motion capture system. In addition, 3D laser scanning to obtain an accurate survey of the building geometry before and after the seismic tests was carried out. In particular, accelerometric recordings were also processed and analyzed using several stationary and nonstationary signal processing techniques with the aim of analyzing the linear behavior of the undamaged structure and the nonlinear structural behavior during damaging shaking table tests. The proposed procedure based on the analysis of magnified videos provided an accurate estimate of the main modal frequency and the damage location through the analysis of the modal shapes, which were confirmed using advanced analyses of the accelerometric data. Consequently, the main novelty of the study was the highlighting of a simple procedure with high potential for the extraction and analysis of modal parameters, with a special focus on the analysis of the modal shape's curvature, which provides accurate information on the location of the damage in a structure, while using a noncontact and low-cost method
A New Selective PPARγ Modulator Inhibits Triglycerides Accumulation during Murine Adipocytes’ and Human Adipose-Derived Mesenchymal Stem Cells Differentiation
Understanding the molecular basis of adipogenesis is vital to identify new therapeutic targets to improve anti-obesity drugs. The adipogenic process could be a new target in the management of this disease. Our aim was to evaluate the effect of GMG-43AC, a selective peroxisome proliferator-activated receptor \u3b3 (PPAR\u3b3) modulator, during adipose differentiation of murine pre-adipocytes and human Adipose Derived Stem Cells (hADSCs). We differentiated 3T3-L1 cells and primary hADSCs in the presence of various doses of GMG-43AC and evaluated the differentiation efficiency measuring lipid accumulation, the expression of specific differentiation markers and the quantification of accumulated triglycerides. The treatment with GMG-43AC is not toxic as shown by cell viability assessments after the treatments. Our findings demonstrate the inhibition of lipid accumulation and the significant decrease in the expression of adipocyte-specific genes, such as PPAR\u3b3, FABP-4, and leptin. This effect was long lasting, as the removal of GMG-43AC from culture medium did not allow the restoration of adipogenic process. The above actions were confirmed in hADSCs exposed to adipogenic stimuli. Together, these results indicate that GMG-43AC efficiently inhibits adipocytes differentiation in murine and human cells, suggesting its possible function in the reversal of adipogenesis and modulation of lipolysis
Probing the low transverse momentum domain of Z production with novel variables
The measurement of the low transverse momentum region of vector boson
production in Drell-Yan processes has long been invaluable to testing our
knowledge of QCD dynamics both beyond fixed-order in perturbation theory as
well as in the non-perturbative region. Recently the D\O\ collaboration have
introduced novel variables which lead to improved measurements compared to the
case of the standard QT variable. To complement this improvement on the
experimental side, we develop here a complete phenomenological study dedicated
in particular to the new \phi* variable. We compare our study, which contains
the state-of-the-art next-to-next-to-leading resummation of large logarithms
and a smooth matching to the full next-to-leading order result, to the
experimental data and find excellent agreement over essentially the entire
range of \phi*, even without direct inclusion of non-perturbative effects. We
comment on our findings and on the potential for future studies to constrain
non-perturbative behaviour.Comment: 20 pages, 7 figures. Version accepted for publication in JHEP. A
figure with comparison to RESBOS has been adde
The CCFM Monte Carlo generator CASCADE 2.2.0
CASCADE is a full hadron level Monte Carlo event generator for ep, \gamma p
and p\bar{p} and pp processes, which uses the CCFM evolution equation for the
initial state cascade in a backward evolution approach supplemented with off -
shell matrix elements for the hard scattering. A detailed program description
is given, with emphasis on parameters the user wants to change and variables
which completely specify the generated events
Production of scalar and pseudo-scalar Higgs bosons to next-to-next-to-leading order at hadron colliders
We consider the production of intermediate-mass CP-even and CP-odd Higgs
bosons in proton-proton and proton-anti-proton collisions. We extend the
recently published results for the complete next-to-next-to-leading order
calculation for a scalar Higgs boson to the pseudo-scalar case and present
details of the calculation that might be useful for similar future
investigations. The result is based on an expansion in the limit of a heavy top
quark mass and a subsequent matching to the expression obtained in the limit of
infinite energy. For a Higgs boson mass of 120 GeV the deviation from the
infinite-top quark mass result is small. For 300 GeV, however, the
next-to-next-to-leading order corrections for a scalar Higgs boson exceed the
effective-theory result by about 9% which increases to 22% in the pseudo-scalar
case. Thus in this mass range the effect on the total cross section amounts to
about 2% and 6%, respectively, which may be relevant in future precision
studies.Comment: 29 page
Finite top quark mass effects in NNLO Higgs boson production at LHC
We present next-to-next-to-leading order corrections to the inclusive
production of the Higgs bosons at the CERN Large Hadron Collider (LHC)
including finite top quark mass effects. Expanding our analytic results for the
partonic cross section around the soft limit we find agreement with a very
recent publication by Harlander and Ozeren \cite{Harlander:2009mq}.Comment: 15 page
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