80 research outputs found
The Updated MSW Analysis and the Standard Solar Model Uncertainties
We update the analysis of the MSW and general astrophysical solutions to the
combined solar neutrino observations by including the GALLEX II result. We also
show that our parametrized flux uncertainties are equivalent to the Monte-Carlo
results of Bahcall and Ulrich.Comment: (Revtex 3.0, convertible to Latex, 10 pages + 6 uuencoded ps figures,
UPR-0581T
Nonnucleosynthetic Constraints on the Baryon Density and Other Cosmological Parameters
Because the baryon-to-photon ratio η_10 is in some doubt, we drop nucleosynthetic constraints on η_10 and fit the three cosmological parameters (h, Ω_M, η_10) to four observational constraints: Hubble parameter h_o = 0.70 ± 0.15, age of the universe t_0 =14^+7_-2 Gyr, cluster gas fraction f_o ≡ f_G h^3/2 = 0.060 ± 0.006, and effective shape parameter Γ_o = 0.255 ± 0.017. Errors quoted are 1 σ, and we assume Gaussian statistics. We experiment with a fifth constraint Ω_o = 0.2 ± 0.1 from clusters. We set the tilt parameter n = 1 and the gas enhancement factor Upsilon = 0.9. We consider cold dark matter models (open and Ω_M = 1) and flat ΛCDM models. We omit HCDM models (to which the Γ_o constraint does not apply). We test goodness of fit and draw confidence regions by the Δχ^2 method. CDM models with Ω_M = 1 (SCDM models) are accepted only because the large error on h_o allows h 0.4. The combination of the four other constraints with Ωo approx 0.2 is rejected in CDM models with 98% confidence, suggesting that light may not trace mass. ΛCDM models give similar results. In all of these models, η_10 ~> 6 is favored strongly over η_10 ~< 2. This suggests that reports of low deuterium abundances on QSO lines of sight may be correct and that observational determinations of primordial ^4He may have systematic errors. Plausible variations on n and Upsilon in our models do not change the results much. If we drop or change the crucial Γ_o constraint, lower values of Ω_M and η_10 are permitted. The constraint Γ_o = 0.15 ± 0.04, derived recently from the IRAS redshift survey, favors Ω_M approx 0.3 and η_10 approx 5 but does not exclude η_10 approx 2
Identifying combinatorial regulation of transcription factors and binding motifs
BACKGROUND: Combinatorial interaction of transcription factors (TFs) is important for gene regulation. Although various genomic datasets are relevant to this issue, each dataset provides relatively weak evidence on its own. Developing methods that can integrate different sequence, expression and localization data have become important. RESULTS: Here we use a novel method that integrates chromatin immunoprecipitation (ChIP) data with microarray expression data and with combinatorial TF-motif analysis. We systematically identify combinations of transcription factors and of motifs. The various combinations of TFs involved multiple binding mechanisms. We reconstruct a new combinatorial regulatory map of the yeast cell cycle in which cell-cycle regulation can be drawn as a chain of extended TF modules. We find that the pairwise combination of a TF for an early cell-cycle phase and a TF for a later phase is often used to control gene expression at intermediate times. Thus the number of distinct times of gene expression is greater than the number of transcription factors. We also see that some TF modules control branch points (cell-cycle entry and exit), and in the presence of appropriate signals they can allow progress along alternative pathways. CONCLUSIONS: Combining different data sources can increase statistical power as demonstrated by detecting TF interactions and composite TF-binding motifs. The original picture of a chain of simple cell-cycle regulators can be extended to a chain of composite regulatory modules: different modules may share a common TF component in the same pathway or a TF component cross-talking to other pathways
Synthesis of tertiary alkylphosphonate oligonucleotides through light-driven radical-polar crossover reactions
光エネルギーで新しい化学修飾核酸を合成 --核酸リン原子の第三級アルキル化に成功--. 京都大学プレスリリース. 2023-11-01.Chemical modification of nucleotides can improve the metabolic stability and target specificity of oligonucleotide therapeutics, and alkylphosphonates have been employed as charge-neutral replacements for naturally-occurring phosphodiester backbones in these compounds. However, at present, the alkyl moieties that can be attached to phosphorus atoms in these compounds are limited to methyl groups or primary/secondary alkyls, and such alkylphosphonate moieties can degrade during oligonucleotide synthesis. The present work demonstrates the tertiary alkylation of the phosphorus atoms of phosphites bearing two 2’-deoxynuclosides. This process utilizes a carbocation generated via a light-driven radical-polar crossover mechanism. This protocol provides tertiary alkylphosphonate structures that are difficult to synthesize using existing methods. The conversion of these species to oligonucleotides having charge-neutral alkylphosphonate linkages through a phosphoramidite-based approach was also confirmed in this study
ホウレンソウ雌性間性株における突然変異誘発ならびに低シュウ酸個体の選抜
This study was conducted to evalute mutagenesis in gynomonoecious spinach (Spinacia oleracea L.) plants for inducing low oxalate variants.Gamma-ray and ion beams of 220 MeV12C5+ and 50MeV 4He2+ ware used as mutagen in seed irradiation. Optimum dosages for irradiation were determined to be about 100Gy, 15-20Gy and 150-200Gy in gamma-ray, 12C5+ and 4He2+, respectively. In M2 generation, there was one line segregating albino seedlings, one line segregating xantha seedlings and two lines segregating dioesious spinach. To save on labor and time for analysis, selection of low oxalate variants in M2generation was conducted by a two-step selebtion which consisted of the first snalysis of bulked leaves from 2 plants as one specimen followed by the second analysis of selected individual plants. In the first analysis of 813 specimens, we selected 13 specimens as low and 9 specimens as high in oxalate content. In the second analysus, there was consistency in the distribution of low and high oxalate content corresponding to the first screening, indicating that selebtion of low oxalate variants could be achived by this two-step selebtion with half the labor and time for analysis as compares to non-bulked method. There were no clear differences in distribution of oxalate content between M3progenies of plants selected as low or high oxalate content, suggesting that the low oxalate content in plants isolated in M2generation was not of a genetic origin. From these results, it seems to be necessary to explore a variant with obvious deviation from the bontinuous variation of oxalate content in the M 2 generation.本実験では,ホウレンソウ雌性間性株における突然変異誘発ならびに低シュウ酸個体の選抜を試みた.種子照射の変異原としては,γ線と220MeV 12
Solutions to Solar Neutrino Anomaly
We present an updated analysis of astrophysical solutions, two-flavor MSW
solutions, and vacuum oscillation solutions to the solar neutrino anomaly. The
recent results of each of the five solar neutrino experiments are incorporated,
including both the zenith angle (day-night) and spectral information from the
Kamiokande experiment, and the preliminary Super-Kamiokande results. New
theoretical developments include the use of the most recent
Bahcall-Pinsonneault flux predictions (and uncertainties) and density and
production profiles, the radiative corrections to the neutrino-electron
scattering cross section, and new constraints on the Ga absorption cross
section inferred from the gallium source experiments. From a model independent
analysis, arbitrary astrophysical solutions are excluded at more that 98% C.L.
even if one ignores any one of the three classes of experiment, relaxes the
luminosity constraint, or allows more suppression of the 7Be than 8B flux. The
data is well described by large and small mixing angle two-flavor MSW
conversions, MSW conversions into a sterile neutrino with small mixing, or
vacuum oscillations. We also present MSW fits for nonstandard solar models
parameterized by an arbitrary solar core temperature or arbitrary 8B flux.Comment: 36p including 21 postscript figures, uses REVTEX 3.1 and epsf.sty,
entire ps file and html file with embedded figures available at
http://www.sns.ias.edu/~hata/papers/anomaly
Solar Model Uncertainties, MSW Analysis, and Future Solar Neutrino Experiments
Various theoretical uncertainties in the standard solar model and in the
Mikheyev-Smirnov-Wolfenstein (MSW) analysis are discussed. It is shown that two
methods of estimating the solar neutrino flux uncertainties are equivalent: (a)
a simple parametrization of the uncertainties using the core temperature and
the nuclear production cross sections; (b) the Monte Carlo method of Bahcall
and Ulrich. In the MSW analysis, we emphasize proper treatments of correlation
of theoretical uncertainties between flux components and between different
detectors, the Earth effect, and multiple solutions in a combined
procedure. The MSW solutions for various standard and nonstandard solar models
are also shown. The MSW predictions of the global solutions for the future
solar neutrino experiments are given, emphasizing the measurement of the energy
spectrum and the day-night effect in Sudbury Neutrino Observatory and
Super-Kamiokande to distinguish the two solutions.Comment: (Revtex 3.0, 43 pages + 26 figures (uuencoded ps files attached),
Easy way: ps files of entire text with embedded figures available by
anonymous ftp://upenn5.hep.upenn.edu/pub/hata/papers/msw_analysis.u
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