Properties of the scalar mesons f0(1370)f_0(1370), f0(1500)f_0(1500) and f0(1710)f_0(1710)

In the three-state mixing framework, considering the possible glueball components of $\eta$ and $\eta^\prime$, we investigate the hadronic decays of $f_0(1370)$, $f_0(1500)$ and $f_0(1710)$ into two pseudoscalar mesons. The quarkonia-glueball content of the three states is determined from the fit to the new data presented by the WA102 Collaboration. We find that these data are insensitive to the possible glueball components of $\eta$ and $\eta^\prime$. Furthermore, we discuss some properties of the mass matrix describing the mixing of the isoscalar scalar mesons.Comment: Latex 14 pages including 1 eps figur

ZOOpt: Toolbox for Derivative-Free Optimization

Recent advances of derivative-free optimization allow efficient approximating the global optimal solutions of sophisticated functions, such as functions with many local optima, non-differentiable and non-continuous functions. This article describes the ZOOpt (https://github.com/eyounx/ZOOpt) toolbox that provides efficient derivative-free solvers and are designed easy to use. ZOOpt provides a Python package for single-thread optimization, and a light-weighted distributed version with the help of the Julia language for Python described functions. ZOOpt toolbox particularly focuses on optimization problems in machine learning, addressing high-dimensional, noisy, and large-scale problems. The toolbox is being maintained toward ready-to-use tool in real-world machine learning tasks

Mutation and Selection on the Wobble Nucleotide in tRNA Anticodons in Marine Bivalve Mitochondrial Genomes

BACKGROUND: Animal mitochondrial genomes typically encode one tRNA for each synonymous codon family, so that each tRNA anticodon essentially has to wobble to recognize two or four synonymous codons. Several factors have been hypothesized to determine the nucleotide at the wobble site of a tRNA anticodon in mitochondrial genomes, such as the codon-anticodon adaptation hypothesis, the wobble versatility hypothesis, the translation initiation and elongation conflict hypothesis, and the wobble cost hypothesis. PRINCIPAL FINDINGS: In this study, we analyzed codon usage and tRNA anticodon wobble sites of 29 marine bivalve mitochondrial genomes to evaluate features of the wobble nucleotides in tRNA anticodons. The strand-specific mutation bias favors G and T on the H strand in all the 29 marine bivalve mitochondrial genomes. A bias favoring G and T is also visible in the third codon positions of protein-coding genes and the wobble sites of anticodons, rejecting that codon usage bias drives the wobble sites of tRNA anticodons or tRNA anticodon bias drives the evolution of codon usage. Almost all codon families (98.9%) from marine bivalve mitogenomes support the wobble versatility hypothesis. There are a few interesting exceptions involving tRNA(Trp) with an anticodon CCA fixed in Pectinoida species, tRNA(Ser) with a GCU anticodon fixed in Mytiloida mitogenomes, and the uniform anticodon CAU of tRNA(Met) translating the AUR codon family. CONCLUSIONS/SIGNIFICANCE: These results demonstrate that most of the nucleotides at the wobble sites of tRNA anticodons in marine bivalve mitogenomes are determined by wobble versatility. Other factors such as the translation initiation and elongation conflict, and the cost of wobble translation may contribute to the determination of the wobble nucleotide in tRNA anticodons. The finding presented here provides valuable insights into the previous hypotheses of the wobble nucleotide in tRNA anticodons by adding some new evidence

Semileptonic Decays of BcB_c Meson to a P-Wave Charmonium State χc\chi_c or hch_c

The semileptonic decays of meson $B_c$ to a P-wave charmonium state $\chi_c(^3P_J)$ or $h_c(^1P_1)$ are computed. The results show that the decays are sizable so they are accessible in Tevatron and in LHC, especially, with the detectors LHCB and BTeV in the foreseeable future, and of them, the one to the $^1P_1$ charmonium state potentially offers us a novel window to see the unconfirmed $h_c$ particle. In addition, it is pointed out that since the two charmonium radiative decays $\chi_c(^3P_{1,2}) \to J/\psi+\gamma$ have sizable branching ratios, the cascade decays of the concerned decays and the charmonium radiative decays may affect the result of the observing the $B_c$ meson through the semileptonic decays $B_{c}\to {J/\psi}+{l}+\nu_{l}$ substantially.Comment: 8 pages, 2 figure

Charge modulation as fingerprints of phase-string triggered interference

Charge order appears to be an ubiquitous phenomenon in doped Mott insulators, which is currently under intense experimental and theoretical investigations particularly in the high $T_c$ cuprates. This phenomenon is conventionally understood in terms of Hartree-Fock type mean field theory. Here we demonstrate a mechanism for charge modulation which is rooted in the many-particle quantum physics arising in the strong coupling limit. Specifically, we consider the problem of a single hole in a bipartite $t-J$ ladder. As a remnant of the fermion signs, the hopping hole picks up subtle phases pending the fluctuating spins, the so-called phase string effect. We demonstrate the presence of charge modulations in the density matrix renormalization group solutions which disappear when the phase strings are switched off. This form of charge modulation can be understood analytically in a path-integral language, showing that the phase strings give rise to constructive interferences leading to self-localization. When the latter occurs, left- and right-moving propagating modes emerge inside the localization volume and their interference is responsible for the real space charge modulation.Comment: 14 pages, 10 figures. Comments on a followup paper by S. R. White, D. J. Scalapino, and S. A. Kivelson (arXiv:1502.04403) adde

Molecular Characterization of the Hedgehog Signaling Pathway and Its Necessary Function on Larval Myogenesis in the Pacific Oyster Crassostrea gigas

Hedgehog signaling pathway participates in a chain of necessary physiological activities and dysregulation of the hedgehog signaling has been implicated in birth defects and diseases. Although substantial studies have uncovered that the hedgehog pathway is both sufficient and necessary for patterning vertebrate muscle differentiation, limited knowledge is available about its role in molluscan myogenesis. Here, the present study firstly identified and characterized the key genes (CgHh, CgPtc, CgSmo, CgGli) in the hedgehog pathway of the Pacific oyster Crassostrea gigas, and investigated the function of this pathway in embryonic myogenesis of C. gigas. Bioinformatics analysis revealed that the functional domains of the key genes were highly conserved among species. Quantitative analysis indicated that CgHh, CgPtc, CgGli mRNA began to accumulate during the blastula to gastrulation stages and accumulated throughout trochophore and into the D-shaped stage. RNA localization patterns by whole-mount in situ hybridization revealed that the key genes own the strongest specific staining in gastrulation, trochophore, and D-shaped stage. Hedgehog pathway genes showed a high expression level in myogenesis stage including trochophore and D-shaped stages, suggesting that the hedgehog pathway would be involved in myogenesis of C. gigas. In adult oysters, the key genes were expressed at various tissues, indicating that hedgehog pathway governed a series of development events. To further examine the role of hedgehog signaling in C. gigas myogenesis, we used cyclopamine treatment in C. gigas larvae to inhibit the signaling pathway. The quantification of the expression of the key genes in hedgehog pathway showed that expressions of key genes were severely down-regulated in treated larvae compared with normal larvae. The velum retractors, ventral retractors, anterior adductor, and posterior adductor muscles of larvae treated with cyclopamine at 4–6 μM for 6–12 h were severely destroyed, suggesting that the hedgehog pathway took part in the myogenesis of C. gigas. These findings provide a foundation for uncovering the molecular mechanisms of hedgehog signaling in molluscan physiological activity and enable us to better understand the signaling pathway involving in molluscan physiological activity

Conflicto lingüístico y separatismo en Canadá

Este artículo analiza la historia del conflicto lingüístico entre el pueblo francófono y el pueblo anglófono dentro de la doble realidad cultural de Canadá y muestra el imperialismo inglés hacia el pueblo québécois a lo largo de su historia. Con respecto a la posible independencia de Quebec, el artículo habla a favor de un Canadá unido sin miedo de ofender a los québécois. Y se desprenden dos conclusiones: una emocional y otra racional. La emocional nos recuerda las palabras del profesor Russell: “Amo a Canadá”, “Canadá es un gran país”. En la racional se nos recuerda las trágicas consecuencias de la desintegración de imperios y naciones. Y se afirma que los québécois no van a vivir mejor si se separan del resto de Canadá. Lo que se necesita verdaderamente es un federalismo más interactivo y más económicamente independiente de los Estados Unidos. This article examines the history of the linguistic conflict between Francophones and Anglophones within the double cultural reality of Canada and shows the English imperialism towards the Quebecois throughout their history. With regard to the possible independence of Quebec, the article discusses Canadian unity without fear of offending the Quebecois. Two conclusions stand out: one emotional and another rational. The emotional one reminds us of Professor Russell’s words: “I love Canada”, “Canada is a great place”. The rational conclusion reminds us of the tragic consequences of the disintegration of empires and nations. It is asserted that the Quebecois will not live better if they separate from the rest of Canada. What the country really needs is a federalism, more interactive and more economically independent from the United States