Present status on experimental search for pentaquarks

It has been ten years since the first report for a positive strangeness pentaquark-like baryon state. However the existence of the pentaquark state is still controversial. Some contradictions between the experiments are unsolved. In this paper we review the experimental search for the pentaquark candidates $\Theta^+$, $\Theta^{++}$, $\Xi^{--}$, $\Theta_c^0$ and $N^*$ in details. We review the experiments with positive results and compare the experiments with similar conditions but opposite results.Comment: 20 latex pages, 2 figures, to appear in IJMPA as a revie

Mitochondrial genetic differentiation across populations of the malaria vector Anopheles lesteri from China (Diptera: Culicidae)

<p>Abstract</p> <p>Background</p> <p><it>Anopheles lesteri </it>is a primary vector of <it>Plasmodium </it>spp. in central China. A complete understanding of vector population structure and the processes responsible for the differentiation is important to the vector-based malaria control programmes and for identifying heterogeneity in disease transmission as a result of discrete vector populations. There is no adequate <it>An. lesteri </it>population genetic data available.</p> <p>Methods</p> <p>Polymorphism of sequence variations in mitochondrial COII and Cytb genes were assessed to explore the level of genetic variability and differentiation among six populations of <it>An. lesteri </it>from China.</p> <p>Results</p> <p>There were 30 (4.37%) and 21 (5.33%) polymorphic sites for mtDNA-COII and Cytb gene, respectively. Totally 31 COII and 30 Cytb haplotypes were obtained. The range of <it>F_ST</it>values was from 0.101 to 0.655 by mtDNA-COII, and 0.029 to 0.231 by Cytb gene. The analysis of molecular variance (AMOVA) showed that the percentage of variation within populations (65.83%, 88.48%) was greater than that among populations (34.17%, 11.52%) using both genes. The Tajima's <it>D </it>and Fu's <it>Fs </it>values were all negative, except Tajima's <it>D </it>values of YN and HNB populations, which suggest a large number of low-frequency mutations in populations and the populations were in expansion proceeding.</p> <p>Conclusions</p> <p>Levels of genetic variation within <it>An. lesteri </it>populations were higher than among them. While these results may suggest considerable levels of gene flow, other explanations, such as the effect of historical population perturbations can also be hypothesized.</p

The Simulated Greedy Algorithm for Several Submodular Matroid Secretary Problems

We study the matroid secretary problems with submodular valuation functions. In these problems, the elements arrive in random order. When one element arrives, we have to make an immediate and irrevocable decision on whether to accept it or not. The set of accepted elements must form an {\em independent set} in a predefined matroid. Our objective is to maximize the value of the accepted elements. In this paper, we focus on the case that the valuation function is a non-negative and monotonically non-decreasing submodular function. We introduce a general algorithm for such {\em submodular matroid secretary problems}. In particular, we obtain constant competitive algorithms for the cases of laminar matroids and transversal matroids. Our algorithms can be further applied to any independent set system defined by the intersection of a {\em constant} number of laminar matroids, while still achieving constant competitive ratios. Notice that laminar matroids generalize uniform matroids and partition matroids. On the other hand, when the underlying valuation function is linear, our algorithm achieves a competitive ratio of 9.6 for laminar matroids, which significantly improves the previous result.Comment: preliminary version appeared in STACS 201

Hvordan jobber pedagogisk leder for inkludering av flerspråklige barn i lek?

For å spisse temaet ‘inkludering av flerspråklige barn’ samt gir instruksjoner i praktisk arbeid, bestemte jeg at problemstillingen ble til: «Hvordan jobber pedagogisk leder for inkludering av flerspråklige barn i lek?

Experimental and Numerical Analysis of Rock Burst Tendency and Crack Development Characteristics of Tianhu Granite

Rock burst is a serious nonlinear dynamic geological hazard in underground engineering construction. In this paper, a true triaxial unloading rock burst experiment and numerical simulation are carried out on Tianhu granite to investigate the rock burst tendency and crack development characteristics of surrounding rock after excavation. The experiment and numerical simulation process monitored the rock burst stress path to determine the rock burst stress. According to the evolution law of the frequency and amplitude of rock burst acoustic emission monitoring, the shape characteristics of rock burst fragments are analyzed. The rock burst numerical simulation analysis is carried out by the PFC software, and the temporal and spatial evolution law of cracks is obtained. The research results show that the laboratory experiment and numerical simulation of Tianhu granite have rock burst strengths of 163.4 MPa and 161 MPa, respectively, and the average rock burst stress ratio is 8.38, that is, the Tianhu granite has a low rock burst tendency. During the rock burst, the development of tensile cracks will produce flaky debris, and the development of shear cracks will produce lumpy debris. Rock burst will happen when the crack growth rate to be exceeded the unloading crack growth rate; therefore, it can be used as a precursor signal for the occurrence of rock burst

Recollements induced by left Frobenius pairs

Let $T$ be a right exact functor from an abelian category $\mathscr{B}$ into another abelian category $\mathscr{A}$. Then there exists an abelian category, named comma category and denoted by $(T\downarrow\mathscr{A})$.In this paper, we construct left Frobenius pairs (resp. strong left Frobenius pairs) over $(T\downarrow\mathscr{A})$ using left Frobenius pairs (resp. strong left Frobenius pairs) over $\mathscr{A}$ and $\mathscr{B}.$ As a consequence, we obtain a recollement of (right) triangulated categories, generalizing the result of Xiong-Zhang-Zhang (J. Algebra 503 (2018) 21-55) about the recollement of additive (resp. triangulated) categories constructed from a triangular matrix algebra. This result is applied to the classes of flat modules and Gorenstein flat modules, the classes of Gorenstein projective modules and Gorenstein projective complexes, the class of Ding projective modules and the class of Gorenstein flat-cotorsion modules.Comment: 24 pages, all comments are welcom

Higher Auslander's defect and classifying substructures of n-exangulated categories

Herschend-Liu-Nakaoka introduced the notion of $n$-exangulated categories. It is not only a higher dimensional analogue of extriangulated categories defined by Nakaoka-Palu, but also gives a simultaneous generalization of $n$-exact categories and $(n+2)$-angulated categories. In this article, we give an $n$-exangulated version of Auslander's defect and Auslander-Reiten duality formula. Moreover, we also give a classification of substructures (=closed subbifunctors) of a given skeletally small $n$-exangulated category by using the category of defects.Comment: 24 pages. arXiv admin note: text overlap with arXiv:1709.06689 by other author

A flat model structure on functor categories

In this paper we construct a flat model structure on the category $_{{\mathcal{Q}},A}{\rm Mod}$ of additive functors from a preadditive category ${\mathcal{Q}}$ satisfying certain conditions to the module category $_{A}{\rm Mod}$, whose homotopy category is the ${\mathcal{Q}}$-shaped derived category introduced by Holm and Jorgensen.Comment: 11 pages. Any comments are very welcom