8,187 research outputs found
Statistical Properties of Interacting Bose Gases in Quasi-2D Harmonic Traps
The analytical probability distribution of the quasi-2D (and purely 2D) ideal
and interacting Bose gas are investigated by using a canonical ensemble
approach. Using the analytical probability distribution of the condensate, the
statistical properties such as the mean occupation number and particle number
fluctuations of the condensate are calculated. Researches show that there is a
continuous crossover of the statistical properties from a quasi-2D to a purely
2D ideal or interacting gases. Different from the case of a 3D Bose gas, the
interaction between atoms changes in a deep way the nature of the particle
number fluctuations.Comment: RevTex, 10pages, 4 figures, E-mail: [email protected]
A QTL for osteoporosis detected in an F2 population derived from White Leghorn chicken lines divergently selected for bone index
Osteoporosis, resulting from progressive loss of structural bone during the period of egg-laying in hens, is associated with an increased susceptibility to bone breakage. To study the genetic basis of bone strength, an F cross was produced from lines of hens that had been divergently selected for bone index from a commercial pedigreed White Leghorn population. Quantitative trait loci (QTL) affecting the bone index and component traits of the index (tibiotarsal and humeral strength and keel radiographic density) were mapped using phenotypic data from 372 F individuals in 32 F families. Genotypes for 136 microsatellite markers in 27 linkage groups covering âŒ80% of the genome were analysed for association with phenotypes using within-family regression analyses. There was one significant QTL on chromosome 1 for bone index and the component traits of tibiotarsal and humeral breaking strength. Additive effects for tibiotarsal breaking strength represented 34% of the trait standard deviation and 7.6% of the phenotypic variance of the trait. These QTL for bone quality in poultry are directly relevant to commercial populations
Baryonic Operators for Lattice Simulations
The construction of baryonic operators for determining the N* excitation
spectrum is discussed. The operators are designed with one eye towards
maximizing overlaps with the low-lying states of interest, and the other eye
towards minimizing the number of sources needed in computing the required quark
propagators. Issues related to spin identification are outlined. Although we
focus on tri-quark baryon operators, the construction method is applicable to
both mesons and penta-quark operators.Comment: 3 pages, poster presented at Lattice2003(spectrum), Tsukuba, Japan,
July 15-19, 200
Group-theoretical construction of extended baryon operators
The design and implementation of large sets of spatially extended baryon
operators for use in lattice simulations are described. The operators are
constructed to maximize overlaps with the low-lying states of interest, while
minimizing the number of sources needed in computing the required quark
propagators.Comment: 3 pages, 3 tables, talk presented at Lattice2004(spectrum), Fermilab,
June 21-26, 200
Optimal life insurance purchase, consumption and investment on a financial market with multi-dimensional diffusive terms
We introduce an extension to Mertonâs famous continuous time model of optimal
consumption and investment, in the spirit of previous works by Pliska and Ye, to allow for
a wage earner to have a random lifetime and to use a portion of the income to purchase life
insurance in order to provide for his estate, while investing his savings in a financial market
comprised of one risk-free security and an arbitrary number of risky securities driven by multidimensional
Brownian motion. We then provide a detailed analysis of the optimal consumption,
investment, and insurance purchase strategies for the wage earner whose goal is to maximize
the expected utility obtained from his family consumption, from the size of the estate in the
event of premature death, and from the size of the estate at the time of retirement. We use
dynamic programming methods to obtain explicit solutions for the case of discounted constant
relative risk aversion utility functions and describe new analytical results which are presented
together with the corresponding economic interpretations.We thank the Calouste Gulbenkian Foundation, PRODYN-ESF, POCTI and POSI by FCT and Ministerio da Ciencia, Tecnologia e Ensino Superior, CEMAPRE, LIAAD-INESC Porto LA, Centro de Matematica da Universidade do Minho and Centro de Matematica da Universidade do Porto for their financial support. D. Pinheiro's research was supported by FCT - Fundacao para a Ciencia e Tecnologia program 'Ciencia 2007' and project 'Randomness in Deterministic Dynamical Systems and Applications' (PTDC/MAT/105448/2008). I. Duarte's research was supported by FCT - Fundacao para a Ciencia e Tecnologia grant with reference SFRH/BD/33502/2008
The [4+2]âCycloaddition of αâNitrosoalkenes with Thiochalcones as a Prototype of Periselective HeteroâDielsâAlder ReactionsâExperimental and Computational Studies
The [4+2]âcycloadditions of αânitrosoalkenes with thiochalcones occur with high selectivity at the thioketone moiety of the dienophile providing styrylâsubstituted 4Hâ1,5,2âoxathiazines in moderate to good yields. Of the eight conceivable heteroâDielsâAlder adducts only this isomer was observed, thus a prototype of a highly periselective and regioselective cycloaddition has been identified. Analysis of crude product mixtures revealed that the αânitrosoalkene also adds competitively to the thioketone moiety of the thiochalcone dimer affording bisâheterocyclic [4+2]âcycloadducts. The experiments are supported by highâlevel DFT calculations that were also extended to related heteroâDielsâAlder reactions of other nitroso compounds and thioketones. These calculations reveal that the title cycloadditions are kinetically controlled processes confirming the role of thioketones as superdienophiles. The computational study was also applied to the experimentally studied thiochalcone dimerization, and showed that the 1,2âdithiin and 2Hâthiopyran isomers are in equilibrium with the monomer. Again, the DFT calculations indicate kinetic control of this process
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