4,278 research outputs found

    Hydrodynamics of the Kuramoto-Sivashinsky Equation in Two Dimensions

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    The large scale properties of spatiotemporal chaos in the 2d Kuramoto-Sivashinsky equation are studied using an explicit coarse graining scheme. A set of intermediate equations are obtained. They describe interactions between the small scale (e.g., cellular) structures and the hydrodynamic degrees of freedom. Possible forms of the effective large scale hydrodynamics are constructed and examined. Although a number of different universality classes are allowed by symmetry, numerical results support the simplest scenario, that being the KPZ universality class.Comment: 4 pages, 3 figure

    QTL Analysis of Mineral Content in Perennial Ryegrass (\u3cem\u3eLolium Perenne\u3c/em\u3e L.)

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    Variation in mineral content of grasses can be strongly influenced by genetic factors. Grass tetany (hypomagnesemia) of cattle and sheep is due to disturbances in serum magnesium levels. In Southern Australia, resultant levels of mortality in cattle vary between 0.5-1.5% of total stock numbers. Serum magnesium variation may be due to feed deficits, or dietary imbalances that interfere with magnesium metabolism. High levels of potassium appear to exert negative effects on the levels of magnesium in the blood. Italian ryegrass genotypes with high levels of magnesium can alleviate the incidence of grass tetany. The genetic control of mineral content, including magnesium, in perennial ryegrass has been investigated using molecular marker-based analysis

    SNP Discovery and Haplotypic Variation in Full-Length Herbage Quality Genes of Perennial Ryegrass (Lolium Perenne L.)

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    The development of forages with enhanced nutritive value through improvements of herbage quality (digestibility, carbohydrate content) is potentially capable of increasing both meat and milk production by up to 25%. However, the expense and time-consuming nature of the relevant biochemical and biophysical assays has limited breeding improvement for forage quality. The development of accurate high-throughput molecular marker-based selection systems such as single nucleotide polymorphisms (SNPs) permits evaluation of genetic variation and selection of favourable variants to accelerate the production of elite new varieties

    Integration of Perennial Ryegrass (L. Perenne) Genetic Maps using Gene-Associated SNPs

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    The reference genetic map of perennial ryegrass was developed by the International Lolium Genome Initiative (ILGI), using the p150/112 one-way pseudo-testcross population. A selection of public domain genetic markers including RFLPs, detected by wheat, barley, oat and rice cDNA probes, and AFLPs were mapped, allowing studies of comparative relationships between perennial ryegrass and other Poaceae species. The map was enhanced through the addition of unique perennial ryegrass genomic DNA-derived SSR (LPSSR) markers, providing the basis of framework genetic mapping in other populations. In addition, a small number of RFLP loci detected by candidate genes involved in herbage quality traits were added to the map. A second-generation reference genetic mapping family was developed based on the F1(NA6 x AU6) two-way pseudo-testcross family, generating two parental genetic maps. These maps were populated by genomic SSR loci, EST-RFLP loci and EST-SSR loci (corresponding to multiple functional categories of agronomic importance). A third genetic mapping population based on an interspecific cross between perennial and annual ryegrass genotypes [F1(Andrea1246 x Lincoln1133)] generated a map based on LPSSR and EST-SSR markers. Linkage groups in the two latter maps were inferred using common LPSSR loci with the p150/112 genetic map

    A factorization of a super-conformal map

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    A super-conformal map and a minimal surface are factored into a product of two maps by modeling the Euclidean four-space and the complex Euclidean plane on the set of all quaternions. One of these two maps is a holomorphic map or a meromorphic map. These conformal maps adopt properties of a holomorphic function or a meromorphic function. Analogs of the Liouville theorem, the Schwarz lemma, the Schwarz-Pick theorem, the Weierstrass factorization theorem, the Abel-Jacobi theorem, and a relation between zeros of a minimal surface and branch points of a super-conformal map are obtained.Comment: 21 page

    A PC parallel port button box provides millisecond response time accuracy under Linux

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    For psychologists, it is sometimes necessary to measure people's reaction times to the nearest millisecond. This article describes how to use the PC parallel port to receive signals from a button box to achieve millisecond response time accuracy. The workings of the parallel port, the corresponding port addresses, and a simple Linux program for controlling the port are described. A test of the speed and reliability of button box signal detection is reported. If the reader is moderately familiar with Linux, this article should provide sufficient instruction for him or her to build and test his or her own parallel port button box. This article also describes how the parallel port could be used to control an external apparatus

    Cooper pair formation in trapped atomic Fermi gases

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    We apply the closed time-path formalism to evaluate the dynamics of the BCS transition to the superfluid state in trapped atomic 6^6Li. We find that the Fokker-Planck equation for the probability distribution of the order parameter is, sufficiently close to the critical temperature, identical to the equation that describes the switching on of a single-mode laser.Comment: 4 pages revtex including 1 figur

    Lifetimes of states in 19Ne above the 15 O + alpha breakup threshold

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    The 15O(alpha,gamma)19Ne reaction plays a role in the ignition of Type I x-ray bursts on accreting neutron stars. The lifetimes of states in 19Ne above the 15O + alpha threshold of 3.53 MeV are important inputs to calculations of the astrophysical reaction rate. These levels in 19Ne were populated in the 3He(20Ne,alpha)19Ne reaction at a 20Ne beam energy of 34 MeV. The lifetimes of six states above the threshold were measured with the Doppler shift attenuation method (DSAM). The present measurements agree with previous determinations of the lifetimes of these states and in some cases are considerably more precise

    Gene-Associated Single Nucleotide Polymorphism (SNP) Discovery in Perennial Ryegrass (\u3cem\u3eLolium Perenne\u3c/em\u3e L.)

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    Perennial ryegrass (Lolium perenne L.) is the most important grass species for temperate pasture systems world-wide. Varietal improvement programs for this obligate outbreeding species are based on polycrossing of multiple parents to produce heterogeneous synthetic populations. The complexity of breeding systems creates challenges and opportunities for molecular marker technology development and implementation. Previous research has led to: the generation of a comprehensive suite of simple sequence repeat (SSR) markers, reference genetic map construction, comparative genetic studies, QTL identification, and population structure analysis. Emphasis has now shifted from the use of anonymous genetic markers linked to trait-specific genes to the development of functionally-associated genetic markers based on candidate genes. The successful implementation of this approach will allow effective selection of parental plants in germplasm collections based on superior allele content
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