Assault on the NLO Wishlist: pp -> tt bb

We present the results of a next-to-leading order calculation of QCD corrections to the production of an on-shell top-anti-top quark pair in association with two flavored b-jets. Besides studying the total cross section and its scale dependence, we give several differential distributions. Where comparable, our results agree with a previous analysis. While the process under scrutiny is of major relevance for Higgs boson searches at the LHC, we use it to demonstrate the ability of our system built around Helac-Phegas to tackle complete calculations at the frontier of current studies for the LHC. On the technical side, we show how the virtual corrections are efficiently computed with Helac-1Loop, based on the OPP method and the reduction code CutTools, using reweighting and Monte Carlo over color configurations and polarizations. As far as the real corrections are concerned, we use the recently published Helac-Dipoles package. In connection with improvements of the latter, we give the last missing integrated dipole formulae necessary for a complete implementation of phase space restriction dependence in the massive dipole subtraction formalism.Comment: 19 pages, 11 figures, 2 tables. References added, version to appear in JHE

Helac-nlo

Based on the OPP technique and the HELAC framework, HELAC-1LOOP is a program that is capable of numerically evaluating QCD virtual corrections to scattering amplitudes. A detailed presentation of the algorithm is given, along with instructions to run the code and benchmark results. The program is part of the HELAC-NLO framework that allows for a complete evaluation of QCD NLO corrections.Comment: minor text revisions, version to appear in Comput.Phys.Commu

On multidimensional poverty rankings of binary attributes

We address the problem of ranking distributions of attributes in terms of poverty, when the attributes are represented by binary variables. To accomplish this task, we identify a suitable notion of “multidimensional poverty line” and characterize axiomatically the Head-Count and the Attribute-Gap poverty rankings, which are the natural counterparts of the most widely used income poverty indices. Finally, we apply our methodology and compare our empirical results with those obtained with some other well-known poverty measures

On Unit Free Assessment of The Extent of Multilateral Distributional Variation

Multilateral comparison of outcomes drawn from multiple groups pervade the social sciences and measurement of their variability, usually involving functions of respective group location and scale parameters, is of intrinsic interest. However, such approaches frequently mask more fundamental differences that more comprehensive examination of relative group distributional structures reveal. Indeed, in categorical data contexts, location and scale based techniques are no longer feasible without artificial and questionable cardinalization of categories. Here, Ginis' Transvariation measure is extended and employed in providing quantitative and visual multilateral comparison tools in discrete, continuous, categorical, univariate or multivariate settings which are particularly useful in paradigms where cardinal measure is absent. Two applications, one analyzing Eurozone cohesion in terms of the convergence or divergence of constituent nations income distributions, the other, drawn from a study of aging, health and income inequality in China, exemplify their use in a continuous and categorical data environment

Hygrothermal characterization of bio-based thermal insulation made of fibres from invasive alien lake plants bounded with mycelium

International audienceThe European program ‘Renovation Wave’ aims to fasten the energy retrofit of the building stock by increasing by a factor 4 the current renovation rate. Mycelium-based materials gained momentum as insulation solutions in recent years due to their 100% biological composition. However, their durability issues, particularly the risk of fast decay due to high moisture content, need to be investigated to promote a safe use in construction. Two bio-composites were set up at a lab scale, a combination of hemp shives and mycelium and a novel mixture based on the combination of mycelium binder and fibres from a lake plant, Lagarosiphon major , an alien invasive species locally available in many EU internal waters. Samples with different dimensions were used to characterize through experimental tests the thermal conductivity, water absorption (capillarity) and vapor permeability. The results show that these mycelium-based composites present both hydric and thermal properties similar to other bio-based material used in construction. The capillarity tests highlighted that hemp composites absorb more water than lake plant ones. The thermal conductivity is similar for both biocomposites, i.e., around 0.05 W/m.K, while the moisture buffer position both analysed biocomposites in “WS 3” according to the German classification DIN 18947 for water regulators

Optimizing the Reduction of One-Loop Amplitudes

We present an optimization of the reduction algorithm of one-loop amplitudes in terms of master integrals. It is based on the exploitation of the polynomial structure of the integrand when evaluated at values of the loop-momentum fulfilling multiple cut-conditions, as emerged in the OPP-method. The reconstruction of the polynomials, needed for the complete reduction, is rended very versatile by using a projection-technique based on the Discrete Fourier Transform. The novel implementation is applied in the context of the NLO QCD corrections to u d-bar --> W+ W- W+

Comparative phenotypic and functional analyses of the effects of autologous plasma and recombinant human macrophage-colony stimulating factor (M-CSF) on porcine monocyte to macrophage differentiation

Abstract Porcine monocyte-derived macrophages (moMΦ) have been employed as a model cell in numerous studies of the porcine immune system. However, the lack of a standardized method for moMΦ differentiation hampers the comparison of results coming from the use of different laboratory protocols. In this study we compared the use of varying concentrations of autologous plasma (10, 20 and 30% v/v) or recombinant human macrophage-colony stimulating factor (hM-CSF; 50, 100, and 200 ng/ml) to differentiate porcine monocytes into macrophages. Changes in cell morphology and surface marker expression were assessed by confocal microscopy and flow cytometry. Macrophage differentiation was evaluated by analysing TNF-α response to LPS stimulation and determining cytokine secretion patterns under both basal conditions and after classical and alternative activation. The effects of the differentiation methods on metabolic activity and susceptibility to infection with the myelotropic African swine fever virus (ASFV) were also evaluated. Monocytes cultured using the different culture conditions tested augmented in dimension and cellular complexity, but increasing porcine plasma concentrations resulted in a dose dependent enhancement in granularity and a marked pleomorphism. As expected, CD163, MHC class II DR and CD203a expression were up-regulated in both hM-CSF (M-CSF-moMΦ) and autologous plasma cultured macrophages (AP-moMΦ), although a lower percentage of CD163+ cells were found following differentiation with high percentages of porcine plasma. We observed enhanced number of viable cells using high concentration of hM-CSF compared to porcine plasma, suggesting a proliferative effect. Irrespective of differentiation conditions, monocyte differentiation into macrophages resulted in an increased susceptibility to ASFV and yielded larger amounts of LPS-induced TNF-α. AP-moMΦ showed a higher basal release of IL-1RA compared to those cultured with hM-CSF and displayed a reduced ability to respond to classical activation, suggesting that the use of high percentages of porcine plasma led to the acquisition of a M2-like phenotype. We conclude that all the protocols tested in this study can be considered as suitable to produce porcine moMΦ, although the use of hM-CSF provides high responsiveness to M1 polarization. Since a higher phenotypic and functional inter-animal variability was observed in AP-moMΦ, we propose that the use of low concentration of hM-CSF should be adopted as the method of choice to provide a better reproducibility between experiments

To dd, or not to dd: Recent developments and comparisons of regularization schemes

We give an introduction to several regularization schemes that deal with ultraviolet and infrared singularities appearing in higher-order computations in quantum field theories. Comparing the computation of simple quantities in the various schemes, we point out similarities and differences between them.Comment: 61 pages, 12 figures; version sent to EPJC, references update

Neutrino physics at large colliders

Large colliders are not sensitive to light neutrino masses and character, but they can produce new heavy neutrinos, allowing also for the determination of their Dirac or Majorana nature. We review the discovery limits at the next generation of large colliders.Comment: LaTeX 32 pages. This review summarises and extends work presented at several conferences. To appear in the proceedings of CORFU2005. References adde

NLO QCD calculations with HELAC-NLO

Achieving a precise description of multi-parton final states is crucial for many analyses at LHC. In this contribution we review the main features of the HELAC-NLO system for NLO QCD calculations. As a case study, NLO QCD corrections for tt + 2 jet production at LHC are illustrated and discussed.Comment: 7 pages, 4 figures. Presented at 10th DESY Workshop on Elementary Particle Theory: Loops and Legs in Quantum Field Theory, Worlitz, Germany, April 25-30, 201