17,705 research outputs found

    Six new species of Integripalpia (Trichoptera) from southern China

    Get PDF
    Six new species ofTrichoptera are described and figured, belonging to the families Goeridae and Leptoceridae. The goerid species are Goera baishanzuensis new species and Goera recta new species. The leptocerid species are Setodes chlorinus new species, Ceraclea (Athripsodina) semicircularis new species, Ceraclea (Athripsodina) brachyclada new species, and Ceraclea (Athripsodina) vaciva new species (Leptoceridae)

    A Matrix-Analytic Solution for Randomized Load Balancing Models with Phase-Type Service Times

    Full text link
    In this paper, we provide a matrix-analytic solution for randomized load balancing models (also known as \emph{supermarket models}) with phase-type (PH) service times. Generalizing the service times to the phase-type distribution makes the analysis of the supermarket models more difficult and challenging than that of the exponential service time case which has been extensively discussed in the literature. We first describe the supermarket model as a system of differential vector equations, and provide a doubly exponential solution to the fixed point of the system of differential vector equations. Then we analyze the exponential convergence of the current location of the supermarket model to its fixed point. Finally, we present numerical examples to illustrate our approach and show its effectiveness in analyzing the randomized load balancing schemes with non-exponential service requirements.Comment: 24 page

    Excitation Spectrum at the Yang-Lee Edge Singularity of 2D Ising Model on the Strip

    Full text link
    At the Yang-Lee edge singularity, finite-size scaling behavior is used to measure the low-lying excitation spectrum of the Ising quantum spin chain for free boundary conditions. The measured spectrum is used to identify the CFT that describes the Yang-Lee edge singularity of the 2D Ising model for free boundary conditions.Comment: 7 pages, 1 figur

    Coherent States and Modified de Broglie-Bohm Complex Quantum Trajectories

    Full text link
    This paper examines the nature of classical correspondence in the case of coherent states at the level of quantum trajectories. We first show that for a harmonic oscillator, the coherent state complex quantum trajectories and the complex classical trajectories are identical to each other. This congruence in the complex plane, not restricted to high quantum numbers alone, illustrates that the harmonic oscillator in a coherent state executes classical motion. The quantum trajectories are those conceived in a modified de Broglie-Bohm scheme and we note that identical classical and quantum trajectories for coherent states are obtained only in the present approach. The study is extended to Gazeau-Klauder and SUSY quantum mechanics-based coherent states of a particle in an infinite potential well and that in a symmetric Poschl-Teller (PT) potential by solving for the trajectories numerically. For the coherent state of the infinite potential well, almost identical classical and quantum trajectories are obtained whereas for the PT potential, though classical trajectories are not regained, a periodic motion results as t --> \infty.Comment: More example

    Direct Collapse to Supermassive Black Hole Seeds with Radiation Transfer: Cosmological Halos

    Get PDF
    We have modeled direct collapse of a primordial gas within dark matter halos in the presence of radiative transfer, in high-resolution zoom-in simulations in a cosmological framework, down to the formation of the photosphere and the central object. Radiative transfer has been implemented in the flux-limited diffusion (FLD) approximation. Adiabatic models were run for comparison. We find that (a) the FLD flow forms an irregular central structure and does not exhibit fragmentation, contrary to adiabatic flow which forms a thick disk, driving a pair of spiral shocks, subject to Kelvin-Helmholtz shear instability forming fragments; (b) the growing central core in the FLD flow quickly reaches ~10 Mo and a highly variable luminosity of 10^{38}-10^{39} erg/s, comparable to the Eddington luminosity. It experiences massive recurrent outflows driven by radiation force and thermal pressure gradients, which mix with the accretion flow and transfer the angular momentum outwards; and (c) the interplay between these processes and a massive accretion, results in photosphere at ~10 AU. We conclude that in the FLD model (1) the central object exhibits dynamically insignificant rotation and slower than adiabatic temperature rise with density; (2) does not experience fragmentation leading to star formation, thus promoting the fast track formation of a supermassive black hole (SMBH) seed; (3) inclusion of radiation force leads to outflows, resulting in the mass accumulation within the central 10^{-3} pc, which is ~100 times larger than characteristic scale of star formation. The inclusion of radiative transfer reveals complex early stages of formation and growth of the central structure in the direct collapse scenario of SMBH seed formation.Comment: 19 pages, 16 figures, MNRAS, accepted for publicatio

    MEAT-GOAT MARKET ANALYSIS: A PILOT STUDY OF THE SOMALI MARKET IN COLUMBUS, OH

    Get PDF
    This case study focuses on meat goat marketing involving one distinct immigrant group residing in one area of Columbus, Ohio: the Somalis. There are about 20,000-25,000 Somalis living in Columbus, the second largest concentration of Somalian immigrants in the U.S. after Minneapolis-St. Paul, Minnesota. It is estimated that Columbus Somalis consume the meat from about 14,000 goats each year. The objective of this pilot study is to analyze the meat goat marketing and consumption patterns of the Somali immigrant population of Columbus, Ohio. Understanding gained in the Somali meat market will assist in determining the feasibility of establishing a more structured marketing system, including the possible need for a processing plant dedicated to goat meat. The Southern Ohio Meat Goat Task Force is a group of meat-goat producers, marketers, OSU extension professionals, and Ohio Cooperative Development Center staff members that are working with the meat-goat industry to assess and develop goat production, processing, and meat marketing in Ohio. Tours of several retail shops within the Somali community were conducted to further understand the preferences of the Somali population. Interviews were conducted with a slaughter-plant manager in nearby Detroit, Michigan, the current major supplier of fresh goat meat to the Columbus market. During January and March 2003, two focus-group sessions were organized and conducted by task force members with Somali consumers, entrepreneurs, and retail grocery owners. Significant results and discussion presented in detail within this research report include: Somalia's prefer fresh over frozen goat meat, pricing is a key determinant in meat choices for Somali consumers, goat meat and lamb meat are somewhat substitutable in Somali diets, Somalis will substitute halal chicken and beef if lamb and goat meat is not available, lean grass-fed carcass is preferred to a grain-fed goat, Somalis eat goat meat 1-2 times a day year-round, most people feeding families buy a whole carcass, and only a slight preference was indicated between the halal and kosher slaughter practices.Agribusiness,
    • …
    corecore