Heavy Flavour Physics at CMS and ATLAS

Prospects for heavy flavour studies with the CMS and ATLAS detectors are presented. Many studies are aimed for early LHC data, taking advantage of the large $b$ production cross-section. Rare decay studies as the $B_s \to \mu^+\mu^-$ decay have also been performed.Comment: Proceedings of the XLIVth Rencontres de Moriond on QCD and High Energy Interaction

Relationship between protein thermodynamic constraints and variation of evolutionary rates among sites

Evolutionary-rate variation among sites within proteins depends on functional and biophysical properties that constrain protein evolution. It is generally accepted that proteins must be able to fold stably in order to function. However, the relationship between stability constraints and among-sites rate variation is not well understood. Here, we present a biophysical model that links the thermodynamic stability changes due to mutations at sites in proteins (ΔΔG) to the rate at which mutations accumulate at those sites over evolutionary time. We find that such a 'stability model' generally performs well, displaying correlations between predicted and empirically observed rates of up to 0.75 for some proteins. We further find that our model has comparable predictive power as does an alternative, recently proposed 'stress model' that explains evolutionary-rate variation among sites in terms of the excess energy needed for mutants to adopt the correct active structure (ΔΔG∗). The two models make distinct predictions, though, and for some proteins the stability model outperforms the stress model and vice versa. We conclude that both stability and stress constrain site-specific sequence evolution in proteins.Fil: Echave, Julián. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Jackson, Eleisha L.. University of Texas at Austin; Estados UnidosFil: Wilke, Claus O.. University of Texas at Austin; Estados Unido

Tradeoff between short-term and long-term adaptation in a changing environment

We investigate the competition dynamics of two microbial or viral strains that live in an environment that switches periodically between two states. One of the strains is adapted to the long-term environment, but pays a short-term cost, while the other is adapted to the short-term environment and pays a cost in the long term. We explore the tradeoff between these alternative strategies in extensive numerical simulations, and present a simple analytic model that can predict the outcome of these competitions as a function of the mutation rate and the time scale of the environmental changes. Our model is relevant for arboviruses, which alternate between different host species on a regular basis.Comment: 9 pages, 3 figures, PRE in pres

Feeding for Hatchability

The Poultry Industry, since its products were designated as essential foods for the Defense Program by Secretary of Agriculture Wickard, has been expanding to meet the requests for increased production in April, 1941

Vitamins In Poultry Nutrition

The field of knowledge on the subject of vitamins in poultry nutrition has become too broad to be covered adequately in one short paper. The practicing veterinarian is concerned chiefly with the symptoms of the various avitaminoses, differential diagnosis, methods of prevention and practical sources of the various vitamins to be used in either prevention or alleviation of the syndromes of each. In this paper, an attempt will be made to present some of this information in very brief form

Controversistas imaginarios: Abraham Gómez Silveyra y los teólogos del exilio hugonote

In the Huguenot refugee community in The Netherlands, known as a hotbed of the early Enlightenment, literary interest in Judaism was ubiquitous, yet actual Dutch Jews were relegated to a marginal position in the exchange of ideas. It is this paradoxical experience of cultural participation and social exclusion that a major unpublished source allows to depict. The ex-converso Abraham Gómez Silveyra (1651–1741), a merchant endowed with rabbinic education and proficiency in French, composed eight manuscript volumes of theological reflections in Spanish literary prose and poetry. This huge clandestine series, which survives in three copies, shows the author’s insatiable curiosity for Christian thought. While rebutting Isaac Jacquelot’s missionary activity, he fraternizes with Pierre Jurieu’s millenarianism, Jacques Basnage’s historiography, and Pierre Bayle’s plea for religious freedom. Gómez Silveyra, however, being painfully aware of his voicelessness in the public sphere, enacts Bayle’s utopian project as a closed performance for a Jewish audience.En la comunidad de refugiados hugonotes en los Países Bajos, conocida como un semillero de la Ilustración temprana, el interés literario por el judaísmo era omnipresente, a pesar de que los judíos holandeses estuviesen relegados a una posición marginal en el intercambio de ideas. Es esta experiencia paradójica de participación cultural y exclusión social la que permite plasmar una importante fuente inédita. El exconverso Abraham Gómez Silveyra (1651-1741), un comerciante dotado de educación rabínica y dominio del francés, compuso en español ocho volúmenes manuscritos de reflexiones teológicas en prosa y poesía literarias. Esta enorme serie clandestina, que sobrevive en tres copias, muestra la insaciable curiosidad del autor por el pensamiento cristiano. Mientras refuta la obra misionera de Isaac Jacquelot, confraterniza con el milenarismo de Pierre Jurieu, la historiografía de Jacques Basnage y la llamada de Pierre Bayle por la libertad religiosa. Dolorosamente consciente de su falta de voz en la esfera pública, Gómez Silveyra encarna el proyecto utópico de Bayle como una actuación cerrada para una audiencia judía

Analyzing Machupo virus-receptor binding by molecular dynamics simulations

In many biological applications, we would like to be able to computationally predict mutational effects on affinity in protein-protein interactions. However, many commonly used methods to predict these effects perform poorly in important test cases. In particular, the effects of multiple mutations, non-alanine substitutions, and flexible loops are difficult to predict with available tools and protocols. We present here an existing method applied in a novel way to a new test case; we interrogate affinity differences resulting from mutations in a host-virus protein-protein interface. We use steered molecular dynamics (SMD) to computationally pull the machupo virus (MACV) spike glycoprotein (GP1) away from the human transferrin receptor (hTfR1). We then approximate affinity using the maximum applied force of separation and the area under the force-versus-distance curve. We find, even without the rigor and planning required for free energy calculations, that these quantities can provide novel biophysical insight into the GP1/hTfR1 interaction. First, with no prior knowledge of the system we can differentiate among wild type and mutant complexes. Moreover, we show that this simple SMD scheme correlates well with relative free energy differences computed via free energy perturbation. Second, although the static co-crystal structure shows two large hydrogen-bonding networks in the GP1/hTfR1 interface, our simulations indicate that one of them may not be important for tight binding. Third, one viral site known to be critical for infection may mark an important evolutionary suppressor site for infection-resistant hTfR1 mutants. Finally, our approach provides a framework to compare the effects of multiple mutations, individually and jointly, on protein-protein interactions.Comment: 33 pages, 8 figures, 5 table

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