79 research outputs found
The Induced Dimension Reduction Method Applied to Convection-Diffusion-Reaction Problems
Discretization of (linearized) convection-diusion-reaction problems yields<br/>a large and sparse non symmetric linear system of equations,<br/>Ax = b: (1)<br/>In this work, we compare the computational behavior of the Induced Dimension<br/>Reduction method (IDR(s)) [10], with other short-recurrences Krylov methods,<br/>specically the Bi-Conjugate Gradient Method (Bi-CG) [1], restarted Generalized<br/>Minimal Residual (GMRES(m)) [4], and Bi-Conjugate Gradient Stabilized method<br/>(Bi-CGSTAB) [11].<br/
Histological changes of liver tissue and serobiochemical relation in does with pregnancy ketosis
Histological changes of liver in does with pregnancy ketosis were characterized. Twenty pregnant does at day 80 of pregnancy were used for this experiment. A total of 10 does were fed by grass (Napier) and goat concentrate with water ad libitum. Those 10 goats considered as healthy pregnant goat, and another 10 goats showing clinical and subclinical signs of ketosis considered as unhealthy pregnant does. Liver biopsies were performed when clinical signs appeared. Beta-Hydroxybutyrate (BHBA), free fatty acid (FFA), and glucose were dosed. Histological preparation revealed similar incidence and intensity of mild liver steatosis with lower cellular vacuolation in hepatocyte presence in healthy late pregnant does. Almost all of the pregnant does with ketosis state (n=8/10) had large amount of small lipid droplets in almost every hepatocyte over the whole liver acinus with higher number of cellular vacuolation, and related with higher BHBA and FFA levels while low in glucose level
Numerical Methods for the QCD Overlap Operator: I. Sign-Function and Error Bounds
The numerical and computational aspects of the overlap formalism in lattice
quantum chromodynamics are extremely demanding due to a matrix-vector product
that involves the sign function of the hermitian Wilson matrix. In this paper
we investigate several methods to compute the product of the matrix
sign-function with a vector, in particular Lanczos based methods and partial
fraction expansion methods. Our goal is two-fold: we give realistic comparisons
between known methods together with novel approaches and we present error
bounds which allow to guarantee a given accuracy when terminating the Lanczos
method and the multishift-CG solver, applied within the partial fraction
expansion methods.Comment: 30 pages, 2 figure
Statistical Mechanics of Broadcast Channels Using Low Density Parity Check Codes
We investigate the use of Gallager's low-density parity-check (LDPC) codes in
a broadcast channel, one of the fundamental models in network information
theory. Combining linear codes is a standard technique in practical network
communication schemes and is known to provide better performance than simple
timesharing methods when algebraic codes are used. The statistical physics
based analysis shows that the practical performance of the suggested method,
achieved by employing the belief propagation algorithm, is superior to that of
LDPC based timesharing codes while the best performance, when received
transmissions are optimally decoded, is bounded by the timesharing limit.Comment: 14 pages, 4 figure
Statistical Mechanics of Broadcast Channels Using Low Density Parity Check Codes
We investigate the use of Gallager's low-density parity-check (LDPC) codes in
a broadcast channel, one of the fundamental models in network information
theory. Combining linear codes is a standard technique in practical network
communication schemes and is known to provide better performance than simple
timesharing methods when algebraic codes are used. The statistical physics
based analysis shows that the practical performance of the suggested method,
achieved by employing the belief propagation algorithm, is superior to that of
LDPC based timesharing codes while the best performance, when received
transmissions are optimally decoded, is bounded by the timesharing limit.Comment: 14 pages, 4 figure
Lattice QCD and the Schwarz alternating procedure
A numerical simulation algorithm for lattice QCD is described, in which the
short- and long-distance effects of the sea quarks are treated separately. The
algorithm can be regarded, to some extent, as an implementation at the quantum
level of the classical Schwarz alternating procedure for the solution of
elliptic partial differential equations. No numerical tests are reported here,
but theoretical arguments suggest that the algorithm should work well also at
small quark masses.Comment: Plain TeX source, 20 pages, figures include
Exact solution of Schrodinger equation for Pseudoharmonic potential
Exact solution of Schrodinger equation for the pseudoharmonic potential is
obtained for an arbitrary angular momentum. The energy eigenvalues and
corresponding eigenfunctions are calculated by Nikiforov-Uvarov method.
Wavefunctions are expressed in terms of Jacobi polynomials. The energy
eigenvalues are calculated numerically for some values of l and n with n<5 for
some diatomic molecules.Comment: 10 page
Meta-analysis of type 2 Diabetes in African Americans Consortium
Type 2 diabetes (T2D) is more prevalent in African Americans than in Europeans. However, little is known about the genetic risk in African Americans despite the recent identification of more than 70 T2D loci primarily by genome-wide association studies (GWAS) in individuals of European ancestry. In order to investigate the genetic architecture of T2D in African Americans, the MEta-analysis of type 2 DIabetes in African Americans (MEDIA) Consortium examined 17 GWAS on T2D comprising 8,284 cases and 15,543 controls in African Americans in stage 1 analysis. Single nucleotide polymorphisms (SNPs) association analysis was conducted in each study under the additive model after adjustment for age, sex, study site, and principal components. Meta-analysis of approximately 2.6 million genotyped and imputed SNPs in all studies was conducted using an inverse variance-weighted fixed effect model. Replications were performed to follow up 21 loci in up to 6,061 cases and 5,483 controls in African Americans, and 8,130 cases and 38,987 controls of European ancestry. We identified three known loci (TCF7L2, HMGA2 and KCNQ1) and two novel loci (HLA-B and INS-IGF2) at genome-wide significance (4.15 × 10(-94)<P<5 × 10(-8), odds ratio (OR) = 1.09 to 1.36). Fine-mapping revealed that 88 of 158 previously identified T2D or glucose homeostasis loci demonstrated nominal to highly significant association (2.2 × 10(-23) < locus-wide P<0.05). These novel and previously identified loci yielded a sibling relative risk of 1.19, explaining 17.5% of the phenotypic variance of T2D on the liability scale in African Americans. Overall, this study identified two novel susceptibility loci for T2D in African Americans. A substantial number of previously reported loci are transferable to African Americans after accounting for linkage disequilibrium, enabling fine mapping of causal variants in trans-ethnic meta-analysis studies.Peer reviewe
Large expert-curated database for benchmarking document similarity detection in biomedical literature search
Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe
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