6,505 research outputs found
Analysis of the Reaction Rate Coefficients for Slow Bimolecular Chemical Reactions
Simple bimolecular reactions are analyzed
within the framework of the Boltzmann equation in the initial stage of a
chemical reaction with the system far from chemical equilibrium. The
Chapman-Enskog methodology is applied to determine the coefficients of the
expansion of the distribution functions in terms of Sonine polynomials for
peculiar molecular velocities. The results are applied to the reaction
, and the influence of the non-Maxwellian
distribution and of the activation-energy dependent reactive cross sections
upon the forward and reverse reaction rate coefficients are discussed.Comment: 11 pages, 5 figures, to appear in vol.42 of the Brazilian Journal of
Physic
The role of sexually dimorphic skin colour and shape in attractiveness of male faces
Evidence for attraction to sexually dimorphic features in male faces is inconsistent in the literature. Mixed results regarding facial masculinity and male attractiveness may arise partly from different influences of face shape and face colouration depending on whether colour was controlled. Recent research suggests that masculinity in face colour, namely darker skin, and femininity in shape are attractive in male faces. Here we examine the influence of sexual dimorphism in skin colour and face shape on attractiveness in 3 experiments. We allowed female participants to manipulate male and female face images along axes of sexual dimorphism in skin colour and/or shape in order to optimise attractiveness. Participants searching for the most attractive appearance chose to masculinise the colour of male faces more than the colour of female faces (although not reaching significance in Experiment 3; p = .16). We found a clear preference for feminine shape in male faces supporting predictions of recent research. These results help to clarify the influence of facial masculinity in women's attractiveness preferences
Effects of 3 Topical Plant Extracts on Wound Healing in Beef Cattle
Eleven heifers of the Purunã cattle breed were used to evaluate wound healing by second intention. An experimental wound excision model in bovines was created by means of a skin punch of diameter 2cm. The animals were topically treated for 17 days with a saline control or decoctions of Schinus terebinthifolius Raddi (Aroeira mansa), Tabebuia avellanedae Lorentz ex Griseb (Ipê Roxo), and Casearia sylvestris Sw.(Guaçatonga) mixed with carboxymethyl cellulose. Centripetal retraction, clinical, and histological aspects of the wounds were observed until complete healing. Decoctions of T. avellanedae and S. terebinthifolius, but not C. sylvestris, had a beneficial effect on wound healing by second intention
Urban stormwater modelling with MOHID
MOHID is a platform that includes a set of numerical models to simulate the water cycle in an integrated approach. It is an open source project that has been developed and applied to a wide range of studies since 1985. To increase its applicability for urban storm water modelling, the main module of the platform MOHID Land is now integrated with SWMM model via OpenMI. This poster evaluates the performance of MOHID in urban storm water modelling, by comparing results of the test cases presented by S. Néelz and G. Pender (2013) and of a real case study with InfoWorks ICM vs. 5.5. Moreover, it is discussed the advantage of covering the entire water cycle in MOHID platform, making it applicable for a wide range of cases
CP properties of symmetry-constrained two-Higgs-doublet models
The two-Higgs-doublet model can be constrained by imposing Higgs-family
symmetries and/or generalized CP symmetries. It is known that there are only
six independent classes of such symmetry-constrained models. We study the CP
properties of all cases in the bilinear formalism. An exact symmetry implies CP
conservation. We show that soft breaking of the symmetry can lead to
spontaneous CP violation (CPV) in three of the classes.Comment: 14 pages, 2 tables, revised version adapted to the journal
publicatio
Purifying Selection in Deeply Conserved Human Enhancers Is More Consistent than in Coding Sequences
(c) 2014 De Silva et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Evaluation of the impact of strain correction on the orientation of cardiac diffusion tensors with in vivo and ex vivo porcine hearts
Purpose To evaluate the importance of strain-correcting stimulated echo acquisition mode echo-planar imaging cardiac diffusion tensor imaging. Methods Healthy pigs (n = 11) were successfully scanned with a 3D cine displacement-encoded imaging with stimulated echoes and a monopolar-stimulated echo-planar imaging diffusion tensor imaging sequence at 3 T during diastasis, peak systole, and strain sweet spots in a midventricular short-axis slice. The same diffusion tensor imaging sequence was repeated ex vivo after arresting the hearts in either a relaxed (KCl-induced) or contracted (BaCl2-induced) state. The displacement-encoded imaging with stimulated echoes data were used to strain-correct the in vivo cardiac diffusion tensor imaging in diastole and systole. The orientation of the primary (helix angles) and secondary (E2A) diffusion eigenvectors was compared with and without strain correction and to the strain-free ex vivo data. Results Strain correction reduces systolic E2A significantly when compared without strain correction and ex vivo (median absolute E2A = 34.3° versus E2A = 57.1° (P = 0.01), E2A = 60.5° (P = 0.006), respectively). The systolic distribution of E2A without strain correction is closer to the contracted ex vivo distribution than with strain correction, root mean square deviation of 0.027 versus 0.038. Conclusions The current strain-correction model amplifies the contribution of microscopic strain to diffusion resulting in an overcorrection of E2A. Results show that a new model that considers cellular rearrangement is required
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