Note on the number of minimal lattice paths restricted by two parallel lines

AbstractThe paper deals with minimal lattice paths from the origin to a point (n,m) which do not cross both two given parallel lines I and II with an incline k (⩾1), but touch the line I a specified number of times. We get the generating functions for the number of distinct minimal lattice paths satisfying these conditions

Parametric Resonance in Neutrino Oscillation: A Guide to Control the Effects of Inhomogeneous Matter Density

Effects of the inhomogeneous matter density on the three-generation neutrino oscillation probability are analyzed. Realistic profile of the matter density is expanded into a Fourier series. Taking in the Fourier modes one by one, we demonstrate that each mode has its corresponding target energy. The high Fourier mode selectively modifies the oscillation probability of the low-energy region. This rule is well described by the parametric resonance between the neutrino oscillation and the matter effect. The Fourier analysis gives a simple guideline to systematically control the uncertainty of the oscillation probability caused by the uncertain density of matter. Precise analysis of the oscillation probability down to the low-energy region requires accurate evaluation of the Fourier coefficients of the matter density up to the corresponding high modes.Comment: 7 pages, 5 eps figure

Quark and Lepton Mass Matrix in an Asymptotically Non-Free Theory

We analyze fermion mass-matrix structure in an asymptotically non-free model with 4 + 1bar generations. The texture at the GUT scale is uniquely determined by supposing that the masses of heavy up-type quarks (charm as well as top) are realized as their infrared fixed point values. By assuming SO(10) GUT-like relations for Yukawa couplings in this model, this texture can explain all fermion masses and quark mixing with only one small parameter, which is almost equal to the Cabibbo angle.Comment: 22 pages, 6 eps figures, typos corrected, version to be publishe

Genome-wide search for strabismus susceptibility loci.

The purpose of this study was to search for chromosomal susceptibility loci for comitant strabismus. Genomic DNA was isolated from 10mL blood taken from each member of 30 nuclear families in which 2 or more siblings are affected by either esotropia or exotropia. A genome-wide search was performed with amplification by polymerase chain reaction of 400 markers in microsatellite regions with approximately 10 cM resolution. For each locus, non-parametric affected sib-pair analysis and non-parametric linkage analysis for multiple pedigrees (Genehunter software, http://linkage.rockefeller.edu/soft/) were used to calculate multipoint lod scores and non-parametric linkage (NPL) scores, respectively. In sib-pair analysis, lod scores showed basically flat lines with several peaks of 0.25 on all chromosomes. In non-parametric linkage analysis for multiple pedigrees, NPL scores showed one peak as high as 1.34 on chromosomes 1, 2, 4, 7, 10, 15, and 16, while 2 such peaks were found on chromosomes 3, 9, 11, 12, 18, and 20. Non-parametric linkage analysis for multiple pedigrees of 30 families with comitant strabismus suggested a number of chromosomal susceptibility loci. Our ongoing study involving a larger number of families will refine the accuracy of statistical analysis to pinpoint susceptibility loci for comitant strabismus.&#60;/P&#62;</p

A temporal mechanism that produces neuronal diversity in the Drosophila visual center

AbstractThe brain consists of various types of neurons that are generated from neural stem cells; however, the mechanisms underlying neuronal diversity remain uncertain. A recent study demonstrated that the medulla, the largest component of the Drosophila optic lobe, is a suitable model system for brain development because it shares structural features with the mammalian brain and consists of a moderate number and various types of neurons. The concentric zones in the medulla primordium that are characterized by the expression of four transcription factors, including Homothorax (Hth), Brain-specific homeobox (Bsh), Runt (Run) and Drifter (Drf), correspond to types of medulla neurons. Here, we examine the mechanisms that temporally determine the neuronal types in the medulla primordium. For this purpose, we searched for transcription factors that are transiently expressed in a subset of medulla neuroblasts (NBs, neuronal stem cell-like neural precursor cells) and identified five candidates (Hth, Klumpfuss (Klu), Eyeless (Ey), Sloppy paired (Slp) and Dichaete (D)). The results of genetic experiments at least explain the temporal transition of the transcription factor expression in NBs in the order of Ey, Slp and D. Our results also suggest that expression of Hth, Klu and Ey in NBs trigger the production of Hth/Bsh-, Run- and Drf-positive neurons, respectively. These results suggest that medulla neuron types are specified in a birth order-dependent manner by the action of temporal transcription factors that are sequentially expressed in NBs

Infra-Red Fixed Points in an Asymptotically Non-Free Theory

We investigate the infrared fixed point structure in asymptotically free and asymptotically non-free theory. We find that the ratios of couplings converge strongly to their infrared fixed points in the asymptotically non-free theory.Comment: 12 pages + 8 eps figures, LaTeX, typos corrected, revised version to be publishe

Genetic variation of γ-tocopherol methyltransferase gene contributes to elevated α-tocopherol content in soybean seeds

<p>Abstract</p> <p>Background</p> <p>Improvement of α-tocopherol content is an important breeding aim to increase the nutritional value of crops. Several efforts have been conducted to improve the α-tocopherol content in soybean [<it>Glycine max </it>(L.) Merr.] through transgenic technology by overexpressing genes related to α-tocopherol biosynthesis or through changes to crop management practices. Varieties with high α-tocopherol content have been identified in soybean germplasms. The heritability of this trait has been characterized in a cross between high α-tocopherol variety Keszthelyi Aproszemu Sarga (KAS) and low α-tocopherol variety Ichihime. In this study, the genetic mechanism of the high α-tocopherol content trait of KAS was elucidated.</p> <p>Results</p> <p>Through QTL analysis and fine mapping in populations from a cross between KAS and a Japanese variety Ichihime, we identified <it>γ-TMT3</it>, which encodes <it>γ</it>-tocopherol methyltransferase, as a candidate gene responsible for high α-tocopherol concentration in KAS. Several nucleotide polymorphisms including two nonsynonymous mutations were found in the coding region of <it>γ-TMT3 </it>between Ichihime and KAS, but none of which was responsible for the difference in α-tocopherol concentration. Therefore, we focused on transcriptional regulation of <it>γ-TMT3 </it>in developing seeds and leaves. An F₅line that was heterozygous for the region containing <it>γ-TMT3 </it>was self-pollinated. From among the progeny, plants that were homozygous at the <it>γ-TMT3 </it>locus were chosen for further evaluation. The expression level of <it>γ-TMT3 </it>was higher both in developing seeds and leaves of plants homozygous for the <it>γ-TMT3 </it>allele from KAS. The higher expression level was closely correlated with high α-tocopherol content in developing seeds. We generated transgenic Arabidopsis plants harboring GUS gene under the control of <it>γ-TMT3 </it>promoter from KAS or Ichihime. The GUS activity assay showed that the activity of <it>γ-TMT3 </it>promoter from KAS was higher than that of Ichihime.</p> <p>Conclusions</p> <p>The genetic variation in <it>γ-TMT3</it>, which plays a major role in determining α-tocopherol concentration, provides significant information about the regulation of tocopherol biosynthesis in soybean seeds. This knowledge will help breeding programs to develop new soybean varieties with high α-tocopherol content.</p