Pseudoscalar Glueball Mass: QCD vs. Lattice Gauge Theory Prediction

We study whether the pseudoscalar glueball mass in full QCD can differ from the prediction of quenched lattice calculations. Using properties of the correlator of the vacuum topological susceptibility we derive an expression for the upper bound on the QCD glueball mass. We show that the QCD pseudoscalar glueball is lighter than the pure Yang-Mills theory glueball studied in quenched lattice calculations. The mass difference between those two states is of order of $1/N_c$. The value calculated for the $0^{-+}$ QCD glueball mass can not be reconciled with any physical state observed so far in the corresponding channel. The glueball decay constant and its production rate in $J/\psi$ radiative decays are calculated. The production rate is large enough to be studied experimentally.Comment: 18 pages, LaTex fil

Multigene phylogeny of the Mustelidae: Resolving relationships, tempo and biogeographic history of a mammalian adaptive radiation

<p>Abstract</p> <p>Background</p> <p>Adaptive radiation, the evolution of ecological and phenotypic diversity from a common ancestor, is a central concept in evolutionary biology and characterizes the evolutionary histories of many groups of organisms. One such group is the Mustelidae, the most species-rich family within the mammalian order Carnivora, encompassing 59 species classified into 22 genera. Extant mustelids display extensive ecomorphological diversity, with different lineages having evolved into an array of adaptive zones, from fossorial badgers to semi-aquatic otters. Mustelids are also widely distributed, with multiple genera found on different continents. As with other groups that have undergone adaptive radiation, resolving the phylogenetic history of mustelids presents a number of challenges because ecomorphological convergence may potentially confound morphologically based phylogenetic inferences, and because adaptive radiations often include one or more periods of rapid cladogenesis that require a large amount of data to resolve.</p> <p>Results</p> <p>We constructed a nearly complete generic-level phylogeny of the Mustelidae using a data matrix comprising 22 gene segments (~12,000 base pairs) analyzed with maximum parsimony, maximum likelihood and Bayesian inference methods. We show that mustelids are consistently resolved with high nodal support into four major clades and three monotypic lineages. Using Bayesian dating techniques, we provide evidence that mustelids underwent two bursts of diversification that coincide with major paleoenvironmental and biotic changes that occurred during the Neogene and correspond with similar bursts of cladogenesis in other vertebrate groups. Biogeographical analyses indicate that most of the extant diversity of mustelids originated in Eurasia and mustelids have colonized Africa, North America and South America on multiple occasions.</p> <p>Conclusion</p> <p>Combined with information from the fossil record, our phylogenetic and dating analyses suggest that mustelid diversification may have been spurred by a combination of faunal turnover events and diversification at lower trophic levels, ultimately caused by climatically driven environmental changes. Our biogeographic analyses show Eurasia as the center of origin of mustelid diversity and that mustelids in Africa, North America and South America have been assembled over time largely via dispersal, which has important implications for understanding the ecology of mustelid communities.</p

A pragmatic trial of acamprosate in the treatment of alcohol dependence in primary care.

To assess the effectiveness of pharmacotherapy with acamprosate in alcohol-dependent patients treated in a naturalistic setting in primary care in France. 422 patients were included. At the end of the study, patients randomized to the acamprosate group had significantly better outcomes in terms of total ARPQ score, change from baseline (–2.61 vs –3.44) and number of subjects with no alcohol-related problem. On average, patients treated with acamprosate had one less alcohol-related problem than did the controls. The number needed to treat in order to save one additional patient from alcohol-related problems compared to standard care was 7.14. Statistically significant differences in favour of the acamprosate group were observed for all secondary efficacy outcome measures including quality of life. Adjunctive therapy with acamprosate in primary care is associated with significantly better functional outcome. Pragmatic trials in alcohol dependence are both feasible and informative.Test de l'efficacité de l'acamprosate en tant que traitement d'apport et de soutien de l'abstinence alcoolique. les valeurs du critères principal (ARPQ) furent significativement inferieures dans le groupe traité. On estime le nombre necessaire à traiter à 7.14. Le traitement étudié est considéré augmenter l'efficience du suivi des patients tant en qualité de vie qu'en consequences sociales

Assessing agricultural risks of climate change in the 21st century in a global gridded crop model intercomparison

Here we present the results from an intercomparison of multiple global gridded crop models (GGCMs) within the framework of the Agricultural Model Intercomparison and Improvement Project and the Inter-Sectoral Impacts Model Intercomparison Project. Results indicate strong negative effects of climate change, especially at higher levels of warming and at low latitudes; models that include explicit nitrogen stress project more severe impacts. Across seven GGCMs, five global climate models, and four representative concentration pathways, model agreement on direction of yield changes is found in many major agricultural regions at both low and high latitudes; however, reducing uncertainty in sign of response in mid-latitude regions remains a challenge. Uncertainties related to the representation of carbon dioxide, nitrogen, and high temperature effects demonstrated here show that further research is urgently needed to better understand effects of climate change on agricultural production and to devise targeted adaptation strategies

Distribution of the Bari-I transposable element in stable hybrid strains between Drosophila melanogaster and Drosophila simulans and in Brazilian populations of these species

We analyzed the distribution of the Bari-I transposable element in Drosophila melanogaster (IN(1)AB), its sibling species Drosophila simulans (C167.4) and in eight hybrid strains derived from initial crosses involving D. simulans females and D. melanogaster males of the above cited strains as well as in Brazilian populations of these species. Polymerase chain reaction (PCR) data showed the presence of the Bari-I element among species populations and hybrid strains. Hybridization with a 703 bp probe homologous to the Bari-I sequence showed that the number of Bari-I copies in D. melanogaster IN(1)AB was higher than in D. simulans C167.4 strains. Hybrid strains presented Bari-I sequences related to both parental species. In addition some strains displayed a Bari-I sequence that came from D. melanogaster, suggesting introgression of D. melanogaster genetic material in the background of D. simulans. In contrast, some hybrids showed deletions of D. simulans Bari-I sequences

HD 19993 and HD 29035: New bright A-type emission-line stars

We present the results of photometric and spectroscopic observations of two A-type stars (HD 19993 and HD 29035), optical counterparts of the IRAS sources (F03108+3729 and 04331+5211, respectively). Hα line emission is found in the optical spectra of both objects for the first time. Our analysis of the spectral line profiles and the photometric information shows that HD 19993 is an A7/8 i