http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
OBSERVATIONAL AND DYNAMICAL CHARACTERIZATION OF MAIN-BELT COMET P/2010 R2 (La Sagra)
Hsieh, Henry H.,Yang, Bin,Haghighipour, Nader,Novaković,, Bojan,Jedicke, Robert,Wainscoat, Richard J.,Denneau, Larry,Abe, Shinsuke,Chen, Wen-Ping,Fitzsimmons, Alan,Granvik, Mikael,Grav, Tommy,Ip, American Institute of Physics 2012 The Astronomical journal Vol.143 No.5
<P>We present observations of the recently discovered comet-like main-belt object P/2010 R2 (La Sagra) obtained by Pan-STARRS1 and the Faulkes Telescope-North on Haleakala in Hawaii, the University of Hawaii 2.2 m, Gemini-North, and Keck I telescopes on Mauna Kea, the Danish 1.54 m telescope (operated by the MiNDSTEp consortium) at La Silla, and the Isaac Newton Telescope on La Palma. An antisolar dust tail is observed to be present from 2010 August through 2011 February, while a dust trail aligned with the object's orbit plane is also observed from 2010 December through 2011 August. Assuming typical phase darkening behavior, P/La Sagra is seen to increase in brightness by >1 mag between 2010 August and December, suggesting that dust production is ongoing over this period. These results strongly suggest that the observed activity is cometary in nature (i.e., driven by the sublimation of volatile material), and that P/La Sagra is therefore the most recent main-belt comet to be discovered. We find an approximate absolute magnitude for the nucleus of H<SUB>R</SUB> = 17.9 ± 0.2 mag, corresponding to a nucleus radius of ~0.7 km, assuming an albedo of p = 0.05. Comparing the observed scattering surface areas of the dust coma to that of the nucleus when P/La Sagra was active, we find dust-to-nucleus area ratios of A<SUB>d</SUB>/A<SUB>N</SUB> = 30-60, comparable to those computed for fellow main-belt comets 238P/Read and P/2008 R1 (Garradd), and one to two orders of magnitude larger than for two other main-belt comets (133P/Elst-Pizarro and 176P/LINEAR). Using optical spectroscopy to search for CN emission, we do not detect any conclusive evidence of sublimation products (i.e., gas emission), finding an upper limit CN production rate of Q<SUB>CN</SUB> < 6 × 10<SUP>23</SUP> mol s<SUP>–1</SUP>, from which we infer an H<SUB>2</SUB>O production rate of <img SRC='http://ej.iop.org/images/1538-3881/143/5/104/aj423523ieqn1.gif' ALIGN='MIDDLE' ALT='$Q_{\rm H_2O}\,{<}\,10^{26}$'/> mol s<SUP>–1</SUP>. Numerical simulations indicate that P/La Sagra is dynamically stable for >100 Myr, suggesting that it is likely native to its current location and that its composition is likely representative of other objects in the same region of the main belt, though the relatively close proximity of the 13:6 mean-motion resonance with Jupiter and the (3,–2,–1) three-body mean-motion resonance with Jupiter and Saturn mean that dynamical instability on larger timescales cannot be ruled out.</P>
Soybean Improvement for Drought, Salt and Flooding Tolerance
Safiullah Pathan,Henry T. Nguyen,Robert E. Sharp,J. Grover Shannon 한국육종학회 2010 한국육종학회지 Vol.42 No.4
Drought, salinity and flooding are three important abiotic factors limiting soybean production worldwide. Irrigation, soil reclamation, and drainage systems are not generally available or economically feasible for soybean production. Therefore, productive soybean varieties with tolerance are a cost effective means for reducing yield losses due to these factors. Genetic variability for higher tolerance to drought, salt and flooding is important. However, only a small portion of nearly 200,000 world soybean accessions have been screened to find genotypes with tolerance for use in breeding programs. Evaluation for tolerance to drought, salinity and flooding is difficult due to lack of faster, cost effective, repeatable screening methods. Soybean strains with higher tolerance to the above stresses have been identified. Crosses with lines with drought, salt and flooding tolerance through conventional breeding has made a significant contribution to improving tolerance to abiotic stress in soybean. Molecular markers associated with tolerance to drought, salt and flooding will allow faster, reliable screening for these traits. Germplasm resources, genome sequence information and various genomic tools are available for soybean. Integration of genomic tools coupled with well-designed breeding strategies and effective uses of these resources will help to develop soybean varieties with higher tolerance to drought, salt and flooding.
Interferometric constraints on quantum geometrical shear noise correlations
Chou, Aaron,Glass, Henry,Richard Gustafson, H,Hogan, Craig J,Kamai, Brittany L,Kwon, Ohkyung,Lanza, Robert,McCuller, Lee,Meyer, Stephan S,Richardson, Jonathan W,Stoughton, Chris,Tomlin, Ray,Weiss, Rai IOP 2017 Classical and quantum gravity Vol.34 No.16
<P>Final measurements and analysis are reported from the first-generation Holometer, the first instrument capable of measuring correlated variations in space-time position at strain noise power spectral densities smaller than a Planck time. The apparatus consists of two co-located, but independent and isolated, 40 m power-recycled Michelson interferometers, whose outputs are cross-correlated to 25 MHz. The data are sensitive to correlations of differential position across the apparatus over a broad band of frequencies up to and exceeding the inverse light crossing time, 7.6 MHz. By measuring with Planck precision the correlation of position variations at spacelike separations, the Holometer searches for faint, irreducible correlated position noise backgrounds predicted by some models of quantum space-time geometry. The first-generation optical layout is sensitive to quantum geometrical noise correlations with shear symmetry—those that can be interpreted as a fundamental noncommutativity of space-time position in orthogonal directions. General experimental constraints are placed on parameters of a set of models of spatial shear noise correlations, with a sensitivity that exceeds the Planck-scale holographic information bound on position states by a large factor. This result significantly extends the upper limits placed on models of directional noncommutativity by currently operating gravitational wave observatories.</P>
Reaction of Soybean Cyst Nematode Resistant Plant Introductions to Root-Knot and Reniform Nematodes
( Jeong Dong Lee ),( Hyun Jee Kim ),( Robert T. Robbins ),( James A. Wrather ),( Jason Bond ),( Henry T. Nguyen ),( J. Grover Shannon ) 한국육종학회 2015 Plant Breeding and Biotechnology Vol.3 No.4
Soybean cyst [SCN, Heterodera glycines Ichinohe], southern root-knot [RKN, Meloidogyne incognita (Kofoid and White) Chitwood] and reniform nematodes [RN, Rotylenchlus reniformis (Linford and Oliveria)] are common plant-parasitic nematode species in southern US fields. Each nematode individually or collectively causes significant economic losses to field grown soybean. A subset of 120 soybean plant introductions (PIs) selected from the USDA Soybean Germplasm Collection have been shown to be resistant to one or more SCN populations (HG Types); however, many of these PIs have not been screened for resistance to either RKN or RN. The objective of this research was to evaluate these germplasm accessions for resistance to RKN and RN. The evaluation for RKN resistance was conducted in RKN infested field plantings after potatoes near Charleston, MO in 2006 and 2007. The evaluation for RN resistance was performed in a greenhouse at Fayetteville, AR, in 2007. Out of these accessions, 64 PIs were identified with high or moderate resistance to RKN. Of these 64 lines, 24 accessions showed good resistance to both RKN and RN. These new sources of resistance to multiple nematodes will be valuable materials for soybean breeding programs to develop new resistant cultivars that can overcome yield losses caused by one or more of these nematode species.
Tran Thien khanh,Ha Pham Thi Thu,Henry Robert. J.,Nguyen Dang Nguyen Thao,Tuyen Phung Thi,Liem Nguyen Thanh 한국미생물·생명공학회 2024 Journal of microbiology and biotechnology Vol.34 No.1
Plants contain a large number of phytochemical components, many of which are known as bioactive compounds and responsible for the expression of various pharmacological activities. The extract of Sonneratia caseolaris fruit collected in Vietnam was investigated for its total phenolic and total flavonoid contents using methanol solvent and different fractions of S. caseolaris fruits (hexane, ethyl acetate, n-butanol, and aqueous). GC–MS analysis was conducted to identify the bioactive chemical constituents occurring in the active extract. Further, the antibacterial activity was tested in vitro on bacterial isolates, namely Escherichia coli, Staphylococcus aureus, and Bacillus subtilis, using the disc diffusion method on tryptic soya agar (TSA) medium. The methanol extract showed high total flavonoid (82.3 ± 0.41 mg QE/g extract) and phenolic (41.0 ± 0.34 mg GAE/g extract) content. GC–MS of the methanol extract and different fractions of S. caseolaris fruits detected 20 compounds, principally fatty alcohols, fatty acids, phenols, lipids, terpenes derivatives, and carboxylic acids derivatives. A 50 mg/ml concentration of methanol extract had the strongest antibacterial activity on E. coli, S. aureus, and B. subtilis. Furthermore, ethyl acetate, aqueous, and n-butanol fractions inhibited S. aureus and B. subtilis the most. The results of the present study suggested that the fruits of S. caseolaris are rich sources of phenolic compounds that can contribute to safe and cost-effective treatments.