Dynamical System Analysis of Cosmologies with Running Cosmological Constant from Quantum Einstein Gravity

We discuss a mechanism that induces a time-dependent vacuum energy on cosmological scales. It is based on the instability induced renormalization triggered by the low energy quantum fluctuations in a Universe with a positive cosmological constant. We employ the dynamical systems approach to study the qualitative behavior of Friedmann-Robertson-Walker cosmologies where the cosmological constant is dynamically evolving according with this nonperturbative scaling at low energies. It will be shown that it is possible to realize a "two regimes" dark energy phases, where an unstable early phase of power-law evolution of the scale factor is followed by an accelerated expansion era at late times.Comment: 26 pages, 4 figures. To appear in New Journal of Physic

Can Twitter be a source of information on allergy? Correlation of pollen counts with tweets reporting symptoms of allergic rhinoconjunctivitis and names of antihistamine drugs

Pollen forecasts are in use everywhere to inform therapeutic decisions for patients with allergic rhinoconjunctivitis (ARC). We exploited data derived from Twitter in order to identify tweets reporting a combination of symptoms consistent with a case definition of ARC and those reporting the name of an antihistamine drug. In order to increase the sensitivity of the system, we applied an algorithm aimed at automatically identifying jargon expressions related to medical terms. We compared weekly Twitter trends with National Allergy Bureau weekly pollen counts derived from US stations, and found a high correlation of the sum of the total pollen counts from each stations with tweets reporting ARC symptoms (Pearson's correlation coefficient: 0.95) and with tweets reporting antihistamine drug names (Pearson's correlation coefficient: 0.93). Longitude and latitude of the pollen stations affected the strength of the correlation. Twitter and other social networks may play a role in allergic disease surveillance and in signaling drug consumptions trends

Inverse bremsstrahlung contributions to Drell-Yan like processes

The contribution of the sub-process $\gamma q \to q' l_1\bar{l}_2$ in hadron-hadron interactions is considered. It is a part of one-loop electroweak radiative corrections for the Drell-Yan production of lepton pairs at hadron colliders. It is shown that this contribution should be taken into account aiming at the 1% accuracy of the Drell-Yan process theoretical description. Both the neutral and charged current cases are evaluated. Numerical results are presented for typical conditions of LHC experiments.Comment: 11 pages, 8 figure

Differential salt-stress response during germination and vegetative growth in in vitro selected somaclonal mutants of Cenchrus ciliaris L.

Four somaclonal mutants (S1, S4, S6 and M10) and their parental Cenchrus ciliaris L. cultivar Biloela were characterized under salinity conditions at germination and vegetative growth stages. Seeds of all somaclonal mutants had higher germination percentages than cv. Biloela seeds in the control and salt treatments. At 150 mM, germination was significantly higher in M10, S6 and S4 (72.3%, 66.3% and 61.8%, respectively) than in cv. Biloela (35.5%). Mutants grown under salinity along with cv. Biloela for 35 days had a different relative growth rate. S6 had the highest growth rate, indicating its potential tolerance to salt stress, whereas M10 was the most sensitive, with Bi, S4 and S1 being intermediate tolerant genotypes. Catalase enzyme activity (CAT) in M10 decreased in response to salt stress and was significantly associated with malondialdehide content, suggesting salt injury, whereas higher levels of CAT activity in S6 during salt stress were associated with increased salinity tolerance. The present results indicate that somaclonal variation and in vitro mutagenesis offer an effective tool for improvement of C. ciliaris because the somaclonal mutants showed differential tolerance to salt stress with respect to their parental and could be a better choice for use in a breeding program.Fil: Lopez Colomba, Eliana. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Fisiología y Recursos Geneticos Vegetales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Tommasino, E.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Fisiología y Recursos Geneticos Vegetales; ArgentinaFil: Luna, Celina Mercedes. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Fisiología y Recursos Geneticos Vegetales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Griffa, Sabrina Mariana. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Fisiología y Recursos Geneticos Vegetales; ArgentinaFil: Carloni, Edgardo José. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Fisiología y Recursos Geneticos Vegetales; ArgentinaFil: Ribotta, Andrea Noemí. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Fisiología y Recursos Geneticos Vegetales; ArgentinaFil: Quiroga, M.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Fisiología y Recursos Geneticos Vegetales; ArgentinaFil: Grunberg, Karina Alejandra. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Fisiología y Recursos Geneticos Vegetales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

A complete one-loop calculation of electroweak supersymmetric effects in tt-channel single top production at LHC

We have computed the complete one-loop electroweak effects in the MSSM for single top (and single antitop) production in the $t$-channel at hadron colliders, generalizing a previous analysis performed for the dominant $dt$ final state and fully including QED effects. The results are quite similar for all processes. The overall Standard Model one-loop effect is small, of the few percent size. This is due to a compensation of weak and QED contributions that are of opposite sign. The genuine SUSY contribution is generally quite modest in the mSUGRA scenario. The experimental observables would therefore only practically depend, in this framework, on the CKM $Wtb$ coupling.Comment: 25 pages, several eps figures. Update corresponding to published versio

Evaluation of the Theoretical Uncertainties in the Z to ll Cross Sections at the LHC

We study the sources of systematic errors in the measurement of the Z to ll cross-sections at the LHC. We consider the systematic errors in both the total cross-section and acceptance for anticipated experimental cuts. We include the best available analysis of QCD effects at NNLO in assessing the effect of higher order corrections and PDF and scale uncertainties on the theoretical acceptance. In addition, we evaluate the error due to missing NLO electroweak corrections and propose which MC generators and computational schemes should be implemented to best simulate the events.Comment: 23 pages, 52 eps figures, LaTeX with JHEP3.cls, epsfig. Added a reference, acknowledgment, and a few clarifying comments. 4/29: Changes in references, minor rewordings and misprint corrections, and one new table (Table 4) comparing CTEQ and MRST PDFs in the NNLO calculation. Version 6 adds email addresses and corrects one referenc

On the Oligomeric State of DJ-1 Protein and Its Mutants Associated with Parkinson Disease A COMBINED COMPUTATIONAL AND IN VITRO STUDY

Mutations in the DJ-1 protein are present in patients suffering from familial Parkinson disease. Here we use computational methods and biological assays to investigate the relationship between DJ-1 missense mutations and the protein oligomeric state. Molecular dynamics calculations suggest that: (i) the structure of DJ-1 wild type (WT) in aqueous solution, in both oxidized and reduced forms, is similar to the crystal structure of the reduced form; (ii) the Parkinson disease-causing M26I variant is structurally similar to the WT, consistent with the experimental evidence showing the protein is a dimer as WT; (iii) R98Q is structurally similar to the WT, consistent with the fact that this is a physiological variant; and (iv) the L166P monomer rapidly evolves toward a conformation significantly different from WT, suggesting a change in its ability to oligomerize. Our combined computational and experimental approach is next used to identify a mutant (R28A) that, in contrast to L166P, destabilizes the dimer subunit-subunit interface without significantly changing secondary structure elements

Radiative corrections to W-boson hadroproduction: higher-order electroweak and supersymmetric effects

The high accuracy envisaged for future measurements of W-boson production at hadron colliders has to be matched by precise theoretical predictions. We study the impact of electroweak radiative corrections on W-boson production cross sections and differential distributions at the Tevatron and at the LHC. In particular, we include photon-induced processes, which contribute at O(alpha), and leading radiative corrections beyond O(alpha) in the high-energy Sudakov regime and from multi-photon final-state radiation. We furthermore present the calculation of the complete supersymmetric next-to-leading-order electroweak and QCD corrections to W-boson hadroproduction within the MSSM. The supersymmetric corrections turn out to be negligible in the vicinity of the W resonance in general, reaching the percent level only at high lepton transverse momentum and for specific choices of the supersymmetric parameters.Comment: 30 pages, 10 figures, 2 new sections, including a comparison with previous results on multi-photon radiation; version published in PR

The phase portrait of a matter bounce in Horava-Lifshitz cosmology

The occurrence of a bounce in FRW cosmology requires modifications of general relativity. An example of such a modification is the recently proposed Horava-Lifshitz theory of gravity, which includes a ``dark radiation'' term with a negative coefficient in the analog of the Friedmann equation. This paper describes a phase space analysis of models of this sort with the aim of determining to what extent bouncing solutions can occur. A simplification, valid in the relevant region, allows a reduction of the dimension of phase space so that visualization in three dimensions is possible. It is found that a bounce is possible, but not generic in models under consideration. Apart from previously known bouncing solutions some new ones are also described. Other interesting solutions found include ones which describe a novel sort of oscillating universes.Comment: 14 pages, 8 figure

Morphological evaluation of buffelgrass cultivar “Lucero INTA-PEMAN” in drought conditions

In searching for new cultivars that are better adapted to edapho-climatic constraints existing in northwestern Argentina, mainly drought and salinity stress, a hybrid of buffelgrass (Cenchrus ciliaris L.) named Lucero INTA PEMAN was obtained by controlled crosses at the Instituto de Fitopatología y Fisiología Vegetal, INTA. The objective was to morphologically evaluate and compare Cenchrus ciliaris cv Lucero with Texas-4464, Biloela and Molopo cultivars in Dean Funes (North of the Province of Córdoba, Argentina) under drought field conditions using a randomized complete block design with three replications in two crop cycles (2006/2007 and 2007/2008) considering one-year plant and re-growth as ontogenic stages of the plant, respectively. Thirteen morphological characters were analyzed by ANOVA and DGC testing (p <0.05). Although most of the thirteen morphological characters evaluated showed decreased re-growth over one-year plants, Lucero was least affected by low water availability, showed highest values for seed production components in both ontogenic stages and was superior to Texas-4464 in biomass production characters and to Biloela and Molopo cultivars in most of them. Lucero showed a promising and considerable forage value for drought-affected regions, such as northwestern Argentina