1,169 research outputs found

    Heavy Higgs boson decays in the alignment limit of the 2HDM

    Get PDF
    The Standard Model (SM)-like couplings of the observed Higgs boson impose strong constraints on the structure of any extended Higgs sector. We consider the theoretical properties and the phenomenological implications of a generic two Higgs doublet model (2HDM). This model constitutes a simple and attractive extension of the SM that is consistent with the observation of the SM-like Higgs boson and precision electroweak observables, while providing a potential new source of CP-violation. In this paper we focus on the so-called Higgs alignment limit of the generic 2HDM, where the neutral scalar field~H1H_1, with the tree-level couplings of the SM Higgs boson, is a mass eigenstate that is aligned in field space with the direction of the Higgs vacuum expectation value. The properties of the two other heavier neutral Higgs scalars, H2H_2 and H3H_3, in the alignment limit of the 2HDM are also elucidated. It is shown that the couplings of H2H_2 and H3H_3 in the alignment limit are tightly constrained and correlated. For example, in the exact alignment limit at tree level, for bosonic final states BR(H2,3W+W,ZZ,H1Z)=0\text{BR}(H_{2,3} \to W^+W^-, ZZ, H_1 Z) = 0 and BR(H±W±H1)=0\text{BR}(H^\pm \to W^\pm H_1) = 0, whereas for fermionic final states Γ(H2ffˉ)/Γ(H3ffˉ)M2/M3\Gamma(H_2 \to f\bar f)/\Gamma(H_3 \to f\bar f) \sim M_2/M_3 (where MαM_\alpha is the mass of HαH_\alpha). In some cases, the results of the alignment limit differ depending on whether or not alignment is achieved via the decoupling of heavy scalar states. In particular, in the exact alignment limit without decoupling BR(H2,3H1H1)=0\text{BR}(H_{2,3}\to H_1 H_1)=0, whereas these branching ratios are nonzero in the decoupling regime. Observables that could be used to test the alignment scenario at the LHC are defined and discussed. The couplings of the Higgs bosons away from their exact alignment values are determined to leading order, and some consequences are elucidated.Comment: 44 pages, 1 figure; v2: references added; v3: major clarifications; v4: JHEP versio

    Dust exposure and chronic respiratory symptoms among coffee curing workers in Kilimanjaro: a cross sectional study

    Get PDF
    Background: Coffee processing causes organic dust exposure which may lead to development of respiratory symptoms. Previous studies have mainly focused on workers involved in roasting coffee in importing countries. This study was carried out to determine total dust exposure and respiratory health of workers in Tanzanian primary coffee-processing factories. Methods: A cross sectional study was conducted among 79 workers in two coffee factories, and among 73 control workers in a beverage factory. Personal samples of total dust (n = 45 from the coffee factories and n = 19 from the control factory) were collected throughout the working shift from the breathing zone of the workers. A questionnaire with modified questions from the American Thoracic Society questionnaire was used to assess chronic respiratory symptoms. Differences between groups were tested by using independent t-tests and Chi square tests. Poisson Regression Model was used to estimate prevalence ratio, adjusting for age, smoking, presence of previous lung diseases and years worked in dusty factories. Results: All participants were male. The coffee workers had a mean age of 40 years and were older than the controls (31 years). Personal total dust exposure in the coffee factories were significantly higher than in the control factory (geometric mean (GM) 1.23 mg/m³, geometric standard deviation (GSD) (0.8) vs. 0.21(2.4) mg/m³). Coffee workers had significantly higher prevalence than controls for cough with sputum (23% vs. 10%; Prevalence ratio (PR); 2.5, 95% CI 1.0 - 5.9) and chest tightness (27% vs. 13%; PR; 2.4, 95% CI 1.1 - 5.2). The prevalence of morning cough, cough with and without sputum for 4 days or more in a week was also higher among coffee workers than among controls. However, these differences were not statistically significant. Conclusion: Workers exposed to coffee dust reported more respiratory symptoms than did the controls. This might relate to their exposure to coffee dust. Interventions for reduction of dust levels and provision of respiratory protective equipment are recommended.publishedVersio

    IL-1beta differently involved in IL-8 and FGF-2 release in crystalline silica-treated lung cell co-cultures

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Inhalation of crystalline silica particles is in humans associated with inflammation and development of fibrosis. The aim of the present study was to investigate the effect of crystalline silica on the release of the fibrosis- and angiogenesis-related mediator FGF-2 and the pro-inflammatory mediator IL-8, and how IL-1β and TNF-α were involved in this release from various mono- and co-cultures of monocytes, pneumocytes and endothelial cells.</p> <p>Results</p> <p>Silica exposure induced an increase of IL-8 release from monocytes and from pneumocytes alone, and the FGF-2 level in the medium increased upon silica exposure of pneumocytes. Both the responses were enhanced in non-contact co-cultures with endothelial cells. The FGF-2 release seemed to increase with the silica-induced decrease in the number of pneumocytes. The release of IL-8 and FGF-2 was partially suppressed in cultures with pneumocytes in contact with monocytes compared to non-contact cultures. Treatment with anti-TNF-α and the IL-1 receptor antagonist revealed that release of IL-1β, and not TNF-α, from monocytes dominated the regulation of IL-8 release in co-cultures. For release of FGF-2, IL-1ra was without effect. However, exogenous IL-1β reduced the FGF-2 levels, strongly elevated the FGF-2-binding protein PTX3, and prevented the reduction in the number of pneumocytes induced by silica.</p> <p>Conclusion</p> <p>IL-1β seems to be differently involved in the silica-induced release of IL-8 and FGF-2 in different lung cell cultures. Whereas the silica-induced IL-8 release is regulated via an IL-1-receptor-mediated mechanism, IL-1β is suggested only indirectly to affect the silica-induced FGF-2 release by counteracting pneumocyte loss. Furthermore, the enhanced IL-8 and FGF-2 responses in co-cultures involving endothelial cells show the importance of the interaction between different cell types and may suggest that both these mediators are important in angiogenic or fibrogenic processes.</p

    Politique Industrielle Contemporaine : le Problème de Dépendance en Energie et Capital Humain des Pays de l’Afrique Centrale

    Get PDF
    This study aims to show that for pro growth industrialization, contemporary industrial policy needs to emphasis on improvement of energy production and of the quality of human capital with application on Central Africa sub region. After a literature review on industrial policy concept, we have highlighted the link between improving energy production, investment in human capital and the level of industrial development through economic growth in Central Africa using a descriptive approach. Indeed produce less energy and unskilled human capital has a negative impact on medium and long term industrial development through economic growth channel. This result has therefore confirmed our recommendation to the implementation of an industrial policy mainly focused on reducing energy dependence and improving the quality of human capital in Central Africa; This, and not to be exhaustive, through increased investment in energy production capacity and in training

    Politique Industrielle Contemporaine : le Problème de Dépendance en Energie et Capital Humain des Pays de l’Afrique Centrale

    Get PDF
    This study aims to show that for pro growth industrialization, contemporary industrial policy needs to emphasis on improvement of energy production and of the quality of human capital with application on Central Africa sub region. After a literature review on industrial policy concept, we have highlighted the link between improving energy production, investment in human capital and the level of industrial development through economic growth in Central Africa using a descriptive approach. Indeed produce less energy and unskilled human capital has a negative impact on medium and long term industrial development through economic growth channel. This result has therefore confirmed our recommendation to the implementation of an industrial policy mainly focused on reducing energy dependence and improving the quality of human capital in Central Africa; This, and not to be exhaustive, through increased investment in energy production capacity and in training

    Analysis of gene order data supports vertical inheritance of the leukotoxin operon and genome rearrangements in the 5' flanking region in genus Mannheimia

    Get PDF
    BACKGROUND: The Mannheimia subclades belong to the same bacterial genus, but have taken divergent paths toward their distinct lifestyles. For example, M. haemolytica + M. glucosida are potential pathogens of the respiratory tract in the mammalian suborder Ruminantia, whereas M. ruminalis, the supposed sister group, lives as a commensal in the ovine rumen. We have tested the hypothesis that vertical inheritance of the leukotoxin (lktCABD) operon has occurred from the last common ancestor of genus Mannheimia to any ancestor of the diverging subclades by exploring gene order data. RESULTS: We examined the gene order in the 5' flanking region of the leukotoxin operon and found that the 5' flanking gene strings, hslVU-lapB-artJ-lktC and xylAB-lktC, are peculiar to M. haemolytica + M. glucosida and M. granulomatis, respectively, whereas the gene string hslVU-lapB-lktC is present in M. ruminalis, the supposed sister group of M. haemolytica + M. glucosida, and in the most ancient subclade M. varigena. In M. granulomatis, we found remnants of the gene string hslVU-lapB-lktC in the xylB-lktC intergenic region. CONCLUSION: These observations indicate that the gene string hslVU-lapB-lktC is more ancient than the hslVU-lapB-artJ-lktC and xylAB-lktC gene strings. The presence of (remnants of) the ancient gene string hslVU-lapB-lktC among any subclades within genus Mannheimia supports that it has been vertically inherited from the last common ancestor of genus Mannheimia to any ancestor of the diverging subclades, thus reaffirming the hypothesis of vertical inheritance of the leukotoxin operon. The presence of individual 5' flanking regions in M. haemolytica + M. glucosida and M. granulomatis reflects later genome rearrangements within each subclade. The evolution of the novel 5' flanking region in M. haemolytica + M. glucosida resulted in transcriptional coupling between the divergently arranged artJ and lkt promoters. We propose that the chimeric promoter have led to high level expression of the leukotoxin operon which could explain the increased potential of certain M. haemolytica + M. glucosida strains to cause a particular type of infection

    An Ellam Scheme for Advection-Diffusion Equations in Two Dimensions

    Get PDF
    We develop an Eulerian{Lagrangian localized adjoint method (ELLAM) to solve two-dimensional advection-diusion equations with all combinations of inflow and outflow Dirichlet, Neumann, and flux boundary conditions. The ELLAM formalism provides a systematic framework for implementation of general boundary conditions, leading to mass-conservative numerical schemes. The computational advantages of the ELLAM approximation have been demonstrated for a number of one-dimensional transport systems; practical implementations of ELLAM schemes in multiple spatial dimensions that require careful algorithm development are discussed in detail in this paper. Extensive numerical results are presented to compare the ELLAM scheme with many widely used numerical methods and to demonstrate the strength of the ELLAM scheme

    Personal Exposure to Dust and Endotoxin in Robusta and Arabica Coffee Processing Factories in Tanzania

    Get PDF
    Introduction: Endotoxin exposure associated with organic dust exposure has been studied in several industries. Coffee cherries that are dried directly after harvest may differ in dust and endotoxin emissions to those that are peeled and washed before drying. The aim of this study was to measure personal total dust and endotoxin levels and to evaluate their determinants of exposure in coffee processing factories. Methods: Using Sidekick Casella pumps at a flow rate of 2l/min, total dust levels were measured in the workers’ breathing zone throughout the shift. Endotoxin was analyzed using the kinetic chromogenic Limulus amebocyte lysate assay. Separate linear mixed-effects models were used to evaluate exposure determinants for dust and endotoxin. Results: Total dust and endotoxin exposure were significantly higher in Robusta than in Arabica coffee factories (geometric mean 3.41 mg/m³ and 10 800 EU/m3 versus 2.10 mg/m³ and 1400 EU/m³, respectively). Dry pre-processed coffee and differences in work tasks explained 30% of the total variance for total dust and 71% of the variance for endotoxin exposure. High exposure in Robusta processing is associated with the dry pre-processing method used after harvest. Conclusions: Dust and endotoxin exposure is high, in particular when processing dry preprocessed coffee. Minimization of dust emissions and use of efficient dust exhaust systems are important to prevent the development of respiratory system impairment in workers
    corecore