62 research outputs found
On the Origin of the Colour-Magnitude Relation in the Virgo Cluster
We explore the origin of the colour-magnitude relation (CMR) of early type
galaxies in the Virgo cluster using spectra of very high S/N ratio for six
elliptical galaxies selected along the CMR. The data are analysed using a new
evolutionary stellar population synthesis model to generate galaxy spectra at
the resolution given by their velocity dispersions. In particular we use a new
age indicator that is virtually free of the effects of metallicity. We find
that the luminosity weighted mean ages of Virgo ellipticals are greater than ~8
Gyr, and show no clear trend with galaxy luminosity. We also find a positive
correlation of metallicity with luminosity, colour and velocity dispersion. We
conclude that the CMR is driven primarily by a luminosity-metallicity
correlation. However, not all elements increase equally with the total
metallicity and we speculate that the CMR may be driven by both a total
metallicity increase and by a systematic departure from solar abundance ratios
of some elements along the CMR. A full understanding of the role played by the
total metallicity, abundance ratios and age in generating the CMR requires the
analysis of spectra of very high quality, such as those reported here, for a
larger number of galaxies in Virgo and other clusters.Comment: To appear in The Astrophysical Journal Letters, 2001 April 20 (551,
number 2). 5 pages and 4 figure
Asymmetric oxidation of 1,2-diols using N-bromosuccinimide in the presence of chiral copper catalyst
Asymmetric oxidation of 1,2-diols using N-bromosuccinimide (NBS) in the presence of copper(II) triflate and (R,R)-Ph-BOX has been exploited. This oxidation was applicable to asymmetric desymmetrization of meso-hydrobenzoin and kinetic resolution of dl-hydrobenzoin and racemic-cycloalkane-cis-1,2-diols to afford optically active ホア-ketoalcohols with good to high enantiomeric excess
Two-photon spectroscopy of core excitons in barium fluoride using synchrotron radiation and laser light
We have conducted two-photon spectroscopy of core excitons in BaF2. Synchrotron radiation and laser light were used for 5p core-electron excitation and Auger-free luminescence was detected as the signal. Two-photon excitation enables access to f and p orbitals that cannot be reached by one-photon excitation of electrons in p orbitals. It has been found that the spin-orbit splittings of 4f and 6p states of the Ba ion in BaF2 are 0.7 +/- 0.1 and 1.4 +/- 0.1 eV, respectively.</p
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Increased tissue levels of omega-3 polyunsaturated fatty acids prevents pathological preterm birth
Omega-3 polyunsaturated fatty acids such as eicosapentaenoic acid (EPA) have anti-inflammatory effects. Preterm birth is an important problem in modern obstetrics and one of the main causes is an inflammation. We here showed that abundance of omega-3 fatty acids reduced the incidence of preterm birth induced by LPS with fat-1 mice, capable of converting omega-6 to omega-3 fatty acids. We also indicated that the gene expression of IL-6 and IL-1β in uteruses and the number of cervical infiltrating macrophages were reduced in fat-1 mice. The analyses of lipid metabolomics showed the high level of 18-hydroxyeicosapentaenoate in fat-1 mice, which was derived from EPA and was metabolized to anti-inflammatory product named resolvin E3 (RvE3). We finally showed that the administration of RvE3 to LPS-exposed pregnant wild type mice lowered the incidence of preterm birth. Our data suggest that RvE3 could be a potential new therapeutic for the prevention of preterm birth
Density Regimes of Complete Detachment and Serpens Mode in LHD
In the Large Helical Device (LHD), the hot plasma column shrinks at the high-density regime and complete detachment takes place. Hydrogen volume recombination is observed at complete detachment. This phase isself-sustained under specific experimental conditions and called the Serpens mode (self-regulated plasma edge ‘neath the last-closed-flux-surface). The Serpens mode is achieved after either rapid or slow density ramp up, and either by hydrogen or helium gas puffing. The threshold conditions for complete detachment and the Serpens mode are experimentally documented in the parameter space of heating power and density. The threshold density for the Serpens mode transition increases with ? 0.4 power of the heating power. The total radiation is shown to be not adequate to describe the threshold conditions, since it mainly includes the information of very edge region outside the hot plasma column. The operational density limit in LHD, which is sustainable in steady state, has been extended to 1.7 times as high as the Sudo density limit, by applying pellet injection to the Serpens plasmas
Asymmetric electrochemical oxidation of 1,2-diols, aminoalcohols and aminoaldehydes in the presence of chiral copper catalyst
Asymmetric oxidation of 1,2-diols, aminoalcohols and aminoaldehydes in the presence of copper(II) triflate and (R,R)-Ph-BOX, was accomplished by electrochemical method using Br- as a mediator. This oxidation was applicable to kinetic resolution of racemic cis-cycloalkane-1,2-diols, aminoalcohols and aminoaldehydes to afford optically active compounds with good to high enantioselectivity
Cost–profit Analysis of Japanese-type Set-net through Technology Transfer in Rayong, Thailand
The Japanese type of set-net, Otoshi-ami, was introduced to Thailand in 2003 with the aim of assessing its feasibility as a sustainable coastal fisheries management tool for the empowerment of coastal fishers’ communities. All preparations for constructing and installing the set-net in the coastal waters off Mae Rumpheung beach, Rayong Province, Thailand, were carried out by local fishers, with technical advice and support from national and international institutions. The gear was modified and developed to suit the conditions of the fishing ground and target species. Data on the catch and sales trends in Rayong using the set-net were collected for 7 years for statistical analysis; during this period, the gear design and marketing strategies were improved. Simulation analysis for evaluating the cost–profit bases was conducted to establish a model for set-net technology transfer in Southeast Asia, based on differing numbers of fishers and operation days. The simulation results show the required size of the average daily catch to cover the total cost according to the average unit price, where the economic return point is an average catch of 128 kg, based on a unit price of 25 Baht/kg (0.83 USD/kg), with ten fishermen and a daily operation cost of 3,200 Baht (USD 106.17)
Mode of Action of Van-M-02, a Novel Glycopeptide Inhibitor of Peptidoglycan Synthesis, in Vancomycin-Resistant Bacteriaâ–¿ â€
Van-M-02, a novel glycopeptide, was revealed to exert potent activities against Gram-positive bacteria, including vancomycin-resistant enterococci (VRE) and vancomycin-resistant Staphylococcus aureus (VRSA). A crude assay system was then used to study the mode of action of Van-M-02 as a peptidoglycan synthesis model of both vancomycin-susceptible and -resistant strains. The results suggested that Van-M-02 inhibits the synthesis of lipid intermediates irrespective of their termini. This inhibitory activity may contribute to the anti-VRE and anti-VRSA activities observed
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