Two-Higgs-doublet model with a color-triplet scalar: a joint explanation for top quark forward-backward asymmetry and Higgs decay to diphoton

The excess of top quark forward-backward asymmetry ($A^t_{FB}$) reported by the Tevatron and the enhancement of the Higgs decay to diphoton observed by the LHC may point to a same origin of new physics. In this note we examined such anomalies in the two-Higgs-doublet model with a color-triplet scalar. We found that under current experimental constraints this model can simultaneously explain both anomalies at $1\sigma$ level. Also, we examined the Higgs decay $h\to Z\gamma$ and displayed its correlation with $h\to \gamma\gamma$. We found that unlike other models, this model predicts a special correlation between $h\to Z\gamma$ and $h\to \gamma\gamma$, i.e., the $Z\gamma$ rate is highly suppressed while the $\gamma\gamma$ rate is enhanced. This behavior may help to distinguish this model in the future high luminosity run of the LHC.Comment: 18pages, 4figures, references adde

Interpreting the 750 GeV diphoton excess by the singlet extension of the Manohar-Wise Model

The evidence of a new scalar particle $X$ from the 750 GeV diphoton excess, and the absence of any other signal of new physics at the LHC so far suggest the existence of new colored scalars, which may be moderately light and thus can induce sizable $X g g$ and $X \gamma \gamma$ couplings without resorting to very strong interactions. Motivated by this speculation, we extend the Manohar-Wise model by adding one gauge singlet scalar field. The resulting theory then predicts one singlet dominated scalar $\phi$ as well as three kinds of color-octet scalars, which can mediate through loops the $\phi gg$ and $\phi \gamma \gamma$ interactions. After fitting the model to the diphoton data at the LHC, we find that in reasonable parameter regions the excess can be explained at $1\sigma$ level by the process $g g \to \phi \to \gamma \gamma$, and the best points predict the central value of the excess rate with $\chi_{min}^2=2.32$, which corresponds to a $p$-value of $0.68$. We also consider the constraints from various LHC Run I signals, and we conclude that, although these constraints are powerful in excluding the parameter space of the model, the best points are still experimentally allowed.Comment: 19 pages, 3 figure

Study on determination of borehole drainage radius by gas content method

In order to determine the radius of borehole gas drainage, using five kinds of gas content under different conditions corresponding to the extraction rate were compared according to different drainage objectives, determine the need for gas drainage amount, according to a certain period of time the average single hole gas drainage quantity, calculate the number of drilling in the region need to be arranged, and then get the borehole gas drainage radius. Based on the actual investigation and comparison analysis, the effective radius of borehole gas drainage in certain extraction time is obtained. The results show that the method of gas content determination of drilling drainage radius is feasible

Gravity Effects on Information Filtering and Network Evolving

In this paper, based on the gravity principle of classical physics, we propose a tunable gravity-based model, which considers tag usage pattern to weigh both the mass and distance of network nodes. We then apply this model in solving the problems of information filtering and network evolving. Experimental results on two real-world data sets, \emph{Del.icio.us} and \emph{MovieLens}, show that it can not only enhance the algorithmic performance, but can also better characterize the properties of real networks. This work may shed some light on the in-depth understanding of the effect of gravity model

GENETIC AND GENOMIC ANALYSIS OF BAHD ACYLTRANSFERASES THAT DECORATE CELL WALL COMPONENTS WITH PHENOLIC ESTERS AND ALTER PLANT BIOMASS RECALCITRANCE

Next generation biofuels make use of the energy stored in plant cell walls, so called lignocellulosic biomass. However, the natural resistance of plant cell walls against deconstruction, i.e., “cell wall recalcitrance”, poses a significant challenge to large-scale commercialization of lignocellulosic biofuels. Grasses, including cereal crops and perennial grasses, are the major source of terrestrial biomass. Previous studies have implicated phenolic acids (ferulic acid and p-coumaric acid) in grass cell wall recalcitrance, but the enzymes that attach these molecules to cell wall precursors are largely unknown. To address this gap, this dissertation accomplished the following: 1) genetic characterization of two so-called “BAHD” acyltransferase genes from rice (Oryza sativa, Os), OsAT5 and OsAT9; 2) examination of the impact of feruloylated lignin on biomass recalcitrance; 3) exploration of cell wall recalcitrance genes in the bioenergy crop, switchgrass, via transcriptomics. To study the enzymes involved in FA decoration in cell walls, we overexpressed a BAHD -coenzyme A acyltransferase, encoded by the OsAT5 gene, in rice and found increased incorporation of feruloyl monolignol conjugates (ML-FAs) in lignin. Cell wall chemical and gene sequence phylogenetic analysis of gymnosperms, dicotyledonous and monocotyledonous plants revealed that incorporation of ML-FAs is wide-spread in angiosperms, but those orthologous genes to OsAT5 are only present in grasses and other commelinid monocot species. These results suggest that angiosperms have convergently evolved the ability to synthesize this newly recognized conjugated lignin precursor. To verify the enzymatic activity and the role of OsAT5 in cell wall decoration, we heterologously expressed the OsAT5 gene in yeast and Arabidopsis, which naturally lack monolignol ferulates. Contrasting the cell wall properties of wild type and transgenic OsAT5 overexpression-rice (Ubipro-OsAT5) and -Arabidopsis (C4Hpro-OsAT5) revealed that, 1) transgenic Arabidopsis exhibited reduced cell wall recalcitrance, whereas transgenic rice lines did not; 2) compared with transgenic rice, transgenic Arabidopsis has a more significant impact on sinapyl ferulate (S-FA) incorporation; 3) when treated with alkaline, wild-type rice lignin, which naturally possesses ML-FA conjugates, shows a higher solubility than wild-type Arabidopsis lignin, consistent with grasses having a more chemically-labile lignin polymer than dicots. The discordant observations in rice and Arabidopsis indicate that ML-FAs produced by OsAT5 have differential impacts on cell wall traits depending on the plant species and tissue, raising the possibility of tailoring lignin structure engineering to different species to tune biomass recalcitrance. To reveal other mechanisms of feruloylation in grasses, we genetically characterized another BAHD acyltransferase, OsAT9, in rice. Overexpression of OsAT9 in rice with the maize Ubi promoter increased the ratio of ferulic acid to p-coumaric acid (FA:pCA) in cell wall polysaccharides and improved extractability of xylan with base treatment, but reduced the enzymatic digestibility of the leaf and stem. These results suggest that OsAT9 is a strong candidate as a feruloyl arabinosyl transferases responsible for feruloylation of rice arabinoxylan by which biomass recalcitrance can be altered. The important agricultural and industrial use of the perennial grass, switchgrass, has generated particular interest in dissecting biomass digestibility-related genes. To accomplish this, we conducted RNA sequencing of four switchgrass genotypes with distinct digestibility, including four sample types (whole elongation 4-stage tiller, leaf, soft stem, and hard stem). The transcriptomes allowed dissection of tissue-specific, lignin biosynthesis- and biomass digestibility-associated genes. We discovered that some protein kinases and cell wall biosynthesis genes are highly related to biomass digestibility and also noted subfunctionalization of putative cell wall-decorating BAHD acyltransferase and lignin biosynthesis genes. This dissertation significantly expands knowledge of cell wall decoration by ferulates, provides insight into the functions of BAHD acyltransferase gene family members and their impacts on cell wall synthesis and biomass recalcitrance in both model plants and food and energy crop species. This study also provides valuable information and new ideas for plant breeding and engineering to create less recalcitrant plant biomass for industrial use and animal forage