Hadronic decays of the highly excited 2D2D DsD_s resonances

Hadronic decays of the highly excited $2D$ $D_s$ resonances have been studied in the $^3P_0$ model. Widths of all possible hadronic decay channels of the $2D$ $D_s$ have been computed. $D^*_{s1}(2700)$, $D^*_{s1}(2860)$, $D^*_{s3}(2860)$, $D(2600)$ and $D(2750)$ can be produced from hadronic decays of the $2D$ $D_s$, and relevant hadronic decay widths have been particularly paid attention to. The hadronic decay widths of $2D$ $D_s$ to $D(2600)$ or $D(2750)$ may be large, and the numerical results are different in different assignments of $D(2600)$ and $D(2750)$. The hadronic decay widths of $2D$ $D_s$ to $D^*_{s1}(2860)$, $D^*_{s3}(2860)$ or $D^*_{s1}(2700)$ are very small, and different in different assignments of $D^*_{s1}(2700)$.Comment: 7 pages, 1 figure. High Energy Physics - Theor

The Sylvester equation and integrable equations: I. The Korteweg-de Vries system and sine-Gordon equation

The paper is to reveal the direct links between the well known Sylvester equation in matrix theory and some integrable systems. Using the Sylvester equation $\boldsymbol{K} \boldsymbol{M}+\boldsymbol{M} \boldsymbol{K}=\boldsymbol{r}\, \boldsymbol{s}^{T}$ we introduce a scalar function $S^{(i,j)}=\boldsymbol{s}^{T}\, \boldsymbol{K}^j(\boldsymbol{I}+\boldsymbol{M})^{-1}\boldsymbol{K}^i\boldsymbol{r}$ which is defined as same as in discrete case. $S^{(i,j)}$ satisfy some recurrence relations which can be viewed as discrete equations and play indispensable roles in deriving continuous integrable equations. By imposing dispersion relations on $\boldsymbol{r}$ and $\boldsymbol{s}$, we find the Korteweg-de Vries equation, modified Korteweg-de Vries equation, Schwarzian Korteweg-de Vries equation and sine-Gordon equation can be expressed by some discrete equations of $S^{(i,j)}$ defined on certain points. Some special matrices are used to solve the Sylvester equation and prove symmetry property $S^{(i,j)}=S^{(i,j)}$. The solution $\boldsymbol{M}$ provides $\tau$ function by $\tau=|\boldsymbol{I}+\boldsymbol{M}|$. We hope our results can not only unify the Cauchy matrix approach in both continuous and discrete cases, but also bring more links for integrable systems and variety of areas where the Sylvester equation appears frequently.Comment: 23 page

Concept Extraction and Clustering for Topic Digital Library Construction

This paper is to introduce a new approach to build topic digital library using concept extraction and document clustering. Firstly, documents in a special domain are automatically produced by document classification approach. Then, the keywords of each document are extracted using the machine learning approach. The keywords are used to cluster the documents subset. The clustered result is the taxonomy of the subset. Lastly, the taxonomy is modified to the hierarchical structure for user navigation by manual adjustments. The topic digital library is constructed after combining the full-text retrieval and hierarchical navigation function

How Can We Predict Performance in Tertiary Level Economics?

The New Zealand Qualification Authority (NZQA) started to introduce a new qualification; the National Certificate of Educational Achievement (NCEA) in 2002. NCEA level 3 replaced the University Bursary Examinations in 2004. The main purpose of this paper is to investigate the relationship between the number and quality of credits gained at NCEA level 3 by students and their academic performance in a first year economics course - Business Economics and the New Zealand Economy at Waikato University. Other factors that could affect student performance are also investigated. Our analysis suggests that several factors can have an impact on student's performance in ECON100. These factors include nationality, semester, total number of NCEA level 3 credits and the quality of credits at level 3 in NCEA economics and mathematics.Qualification, Education, Testing, Teaching/Communication/Extension/Profession,

Moth pheromone receptors: gene sequences, function, and evolution

The detection of female-released species-specific sex pheromones in moths is mediated by the pheromone receptors that are expressed in the sensory neurons in the olfactory sensilla of conspecific male antennae. Since the pioneering studies on the tobacco budworm Heliothis virescens and the silkworm Bombyx mori a decade ago, genes encoding pheromone receptors have been identified from a number of moth species. Pheromone receptor genes constitute a specialized olfactory receptor subfamily that shares sequence homology. In most cases the pheromone receptor genes are more abundantly expressed in male antennae, and the expression is confined to the neurons in the long sensilla trichodea, which are responsible for pheromone sensing. Both highly specific and more broadly tuned pheromone receptors have been described in various moth species. We review the advances in moth pheromone receptor studies over the past decade, including the methods used in receptor gene isolation and functional characterization, the different ligand profiles of the identified receptors, and the evolution of this multigene family