2,184 research outputs found

    A description of the transverse momentum distributions of charged particles produced in heavy ion collisions at RHIC and LHC energies

    Full text link
    By assuming the existing of memory effects and long-range interactions in the hot and dense matter produced in high energy heavy ion collisions, the nonextensive statistics together with the relativistic hydrodynamics including phase transition is used to discuss the transverse momentum distributions of charged particles produced in heavy ion collisions. It is shown that the combined contributions from nonextensive statistics and hydrodynamics can give a good description to the experimental data in Au+Au collisions at sqrt(s_NN )= 200 GeV and in Pb+Pb collisions at sqrt(s_NN) )= 2.76 TeV for pi^(+ -) , K^(+ -) in the whole measured transverse momentum region, and for p(p-bar) in the region of p_T<= 2.0 GeV/c. This is different from our previous work, where, by using the conventional statistics plus hydrodynamics, the describable region is only limited in p_T<= 1.1 GeV/c.Comment: 14 pages, 3 figures, 2 table

    Unitary Constraints on Semiclassical Schwarzschild Black Holes in the Presence of Island

    Full text link
    We reconsider D≥4D\geq4 dimensional asymptotically flat eternal Schwarzschild black hole, and focus on the situation where the inner boundary of the radiation region is chosen to be near the horizon (i.e. β≪1\beta\ll 1). The tension between the near horizon condition and the short-distance approximation emerges in large dimensions in previous papers. We remove this tension by introducing a more proper near horizon condition, thus the resulting island solution is well-behaved in any D≥4D\geq4 dimensional spacetime. Interestingly, a novel constraint is obtained in this situation as required by the existence of the island solution, which directly leads to the constraints on the size of the Schwarzschild black hole, the position of the inner boundary for the radiation region, or the value of c⋅G~Nc\cdot\tilde{G}_{N} in any D≥4D\geq4 dimension. When considering the large DD limit, the constraint on the size of the Schwarzschild black hole obtained in this situation is in agreement with the result given in [Phys.Rev.D102(2020)2,026016][Phys.Rev.D 102 (2020) 2, 026016]. We interpret these as the unitary constraints implied by the presence of island in semiclassical gravity.Comment: 21 pages, 4 figures; new contents added in Section 3.2 to derive the constraint, also many related modification

    A New Algorithm for Boolean Operations on General Polygons

    Get PDF
    International audienceA new algorithm for Boolean operations on general planar polygons is presented. It is available for general planar polygons (manifold or non-manifold, with or without holes). Edges of the two general polygons are subdivided at the intersection points and touching points. Thus, the boundaryof the Boolean operation resultant polygon is made of some whole edges of the polygons after the subdivision process. We use the simplex theory to build the basic mathematical model of the new algorithm. The subordination problem between an edge and a polygon is reduced to a problem of determining whether a point is on some edges of some simplices or inside the simplices, and the associated simplicial chain of the resultant polygon is just an assembly of some simplices and their coefficients of the two polygons after the subdivision process. Examples show that the running time required bythe new algorithm is less than one-third of that bythe Rivero and Feito algorithm

    Phylogenetic structure and formation mechanism of shrub communities in arid and semiarid areas of the Mongolian Plateau

    Get PDF
    The mechanisms of species coexistence within a community have always been the focus in ecological research. Community phylogenetic structure reflects the relationship of historical processes, regional environments, and interactions between species, and studying it is imperative to understand the formation and maintenance mechanisms of community composition and biodiversity. We studied the phylogenetic structure of the shrub communities in arid and semiarid areas of the Mongolian Plateau. First, the phylogenetic signals of four plant traits (height, canopy, leaf length, and leaf width) of shrubs and subshrubs were measured to determine the phylogenetic conservation of these traits. Then, the net relatedness index (NRI) of shrub communities was calculated to characterize their phylogenetic structure. Finally, the relationship between the NRI and current climate and paleoclimate (since the Last Glacial Maximum, LGM) factors was analyzed to understand the formation and maintenance mechanisms of these plant communities. We found that desert shrub communities showed a trend toward phylogenetic overdispersion; that is, limiting similarity was predominant in arid and semiarid areas of the Mongolian Plateau despite the phylogenetic structure and formation mechanisms differing across habitats. The typical desert and sandy shrub communities showed a significant phylogenetic overdispersion, while the steppified desert shrub communities showed a weak phylogenetic clustering. It was found that mean winter temperature (i.e., in the driest quarter) was the major factor limiting steppified desert shrub phylogeny distribution. Both cold and drought (despite having opposite consequences) differentiated the typical desert to steppified desert shrub communities. The increase in temperature since the LGM is conducive to the invasion of shrub plants into steppe grassland, and this process may be intensified by global warming

    Research Progress on the Relevance between Intestinal Flora and Colorectal Cancer

    Get PDF
    Cancer is a common chronic disease all over the world, which will cause serious health burden. At present, the debate about the role of intestinal flora in the prevention and control of cancer has always existed. Therefore, researchers should pay close attention to the impact of intestinal flora on several cancers (such as colon cancer, liver cancer and breast cancer). In addition, it is reported that intestinal flora may also affect the efficacy of cancer chemotherapy and immunotherapy. This paper introduces some energy research results to help clear the relationship between intestinal flora and cancer, even cancer micro environment. It can help clarify the mist of cancer and gut microbiota, let those little creatures to serve the progress of improving mankind living condition and of health and medicine

    Polarization-based probabilistic discriminative model for quantitative characterization of cancer cells

    Get PDF
    We propose a polarization-based probabilistic discriminative model for deriving a set of new sigmoid-transformed polarimetry feature parameters, which not only enables accurate and quantitative characterization of cancer cells at pixel level, but also accomplish the task with a simple and stable model. By taking advantages of polarization imaging techniques, these parameters enable a low-magnification and wide-field imaging system to separate the types of cells into more specific categories that previously were distinctive under high magnification. Instead of blindly choosing the model, the L0 regularization method is used to obtain the simplified and stable polarimetry feature parameter. We demonstrate the model viability by using the pathological tissues of breast cancer and liver cancer, in each of which there are two derived parameters that can characterize the cells and cancer cells respectively with satisfactory accuracy and sensitivity. The stability of the final model opens the possibility for physical interpretation and analysis. This technique may bypass the typically labor-intensive and subjective tumor evaluating system, and could be used as a blueprint for an objective and automated procedure for cancer cell screening

    2-{[3-Methyl-4-(2,2,2-trifluoro­eth­oxy)pyridin-2-yl]methyl­sulfan­yl}-1H-benzimidazole monohydrate

    Get PDF
    The asymmetric unit of the title compound, C16H14F3N3OS·H2O, contains two independent mol­ecules (A and B) and two water mol­ecules, one of which is disordered over two positions in a 0.790 (8):0.210 (8) ratio. The mol­ecular conformations are close, the benzimidazole mean plane and pyridine ring forming dihedral angles of 1.8 (3) and 0.1 (2)° in mol­ecules A and B, respectively. The water mol­ecules are involved in formation of two independent hydrogen-bonded chains via N—H⋯O and O—H⋯N hydrogen bonds. Chains propagating along the a axis are formed by mol­ecule A and one independent water mol­ecule, while chains propagating along the b axis are formed by mol­ecule B and the other independent water mol­ecule. The crystal packing exhibits π–π inter­actions, as indicated by short distances of 3.607 (3) and 3.701 (3) Å between the centroids of the imidazole and pyridine rings of neighbouring mol­ecules
    • …
    corecore