974 research outputs found
Phylogeography of a widespread terrestrial vertebrate in a barely-studied Palearctic region: green toads (Bufo viridis subgroup) indicate glacial refugia in Eastern Central Asia.
The phylogeography of western Palearctic species is relatively well studied, but data on Eastern Central Asia are scarce. We present one of the first data sets from a widespread terrestrial vertebrate (Bufo pewzowi) inhabiting Eastern Central Asian mountains and deserts to gain knowledge on its phylogeography in this region. We applied combined phylogenetic and demographic analyses to understand the evolutionary history using mitochondrial DNA D-loop variation of toads from 37 locations. Genetic structure of Bufo pewzowi is strongly affected by landscape: we found three haplotype groups in eastern Kazakhstan, Dzungaria and Tarim Basin, divided by the Tian Shan and Dzungarian Alatau ranges. A vicariant hypothesis may explain divergence among groups. The divergence time of the three major clades was estimated about 0.9 million years ago (confidence interval 0.5-1.4), and is discussed with respect to Quaternary uplifting and glaciation in the Tian Shan. Demographic analyses provided evidence for both historical bottlenecks and population expansions and suggested Pleistocene signatures. Glacial refugia were inferred in the Tarim Basin (around the Turpan depression), in southern Dzungaria (Urumqui region), at the northern foot of the Tian Shan (Gongnaisi) and perhaps at the Altai range (Terekti). Regional Post-Last Glacial Maximum dispersal patterns are proposed. A taxonomic hypothesis is presented. This study provides a detailed history of how a widespread terrestrial vertebrate responded to geological change and Quaternary glacial events in Eastern Central Asia and may have significance for future phylogeographic research in this understudied region
Identification of rice chromosome segment substitution line Z322-1-10 and mapping QTLs for agronomic traits from the F<sub>3</sub> population
Chromosome segment substitution lines (CSSLs) are powerful tools to combine naturally occurring genetic variants with favorable alleles in the same genetic backgrounds of elite cultivars. An elite CSSL Z322-1-10 was identified from advanced backcrosses between a japonica cultivar Nipponbare and an elite indica restorer Xihui 18 by SSR marker-assisted selection (MAS). The Z322-1-10 line carries five substitution segments distributed on chromosomes 1, 2, 5, 6 and 10 with an average length of 4.80 Mb. Spikilets per panicle, 1000-grain weight, grain length in the Z322-1-10 line are significantly higher than those in Nipponbare. Quantitative trait loci (QTLs) were identified and mapped for nine agronomic traits in an F3 population derived from the cross between Nipponbare and Z322-1-10 using the restricted maximum likelihood (REML) method in the HPMIXED procedure of SAS. We detected 13 QTLs whose effect ranging from 2.45% to 44.17% in terms of phenotypic variance explained. Of the 13 loci detected, three are major QTL (qGL1, qGW5-1 and qRLW5-1) and they explain 34.68%, 44.17% and 33.05% of the phenotypic variance. The qGL1 locus controls grain length with a typical Mendelian dominance inheritance of 3:1 ratio for long grain to short grain. The already cloned QTL qGW5-1 is linked with a minor QTL for grain width qGW5-2 (13.01%) in the same substitution segment. Similarly, the previously reported qRLW5-1 is also linked with a minor QTL qRLW5-2. Not only the study is important for fine mapping and cloning of the gene qGL1, but also has a great potential for molecular breeding
Properties and Performance of Two Wide Field of View Cherenkov/Fluorescence Telescope Array Prototypes
A wide field of view Cherenkov/fluorescence telescope array is one of the
main components of the Large High Altitude Air Shower Observatory project. To
serve as Cherenkov and fluorescence detectors, a flexible and mobile design is
adopted for easy reconfiguring of the telescope array. Two prototype telescopes
have been constructed and successfully run at the site of the ARGO-YBJ
experiment in Tibet. The features and performance of the telescopes are
presented
New Upper Limit of Terrestrial Equivalence Principle Test for Rotating Extended Bodies
Improved terrestrial experiment to test the equivalence principle for
rotating extended bodies is presented, and a new upper limit for the violation
of the equivalence principle is obtained at the level of 1.6, which is limited by the friction of the rotating gyroscope. It
means the spin-gravity interaction between the extended bodies has not been
observed at this level.Comment: 4 page
Avoidance of multicast incapable branching nodes for multicast routing in WDM networks
In this articlewestudy themulticast routing problem in all-opticalWDMnetworks
under the spare light splitting constraint. To implement a multicast session,
several light-trees may have to be used due to the limited fanouts of network
nodes. Although many multicast routing algorithms have been proposed in order
to reduce the total number of wavelength channels used (total cost) for a
multicast session, the maximum number of wavelengths required in one fiber link
(link stress) and the end-to-end delay are two parameters which are not always
taken into consideration. It is known that the shortest path tree (SPT) results
in the optimal end-to-end delay, but it can not be employed directly for
multicast routing in sparse light splitting WDM networks. Hence, we propose a
novel wavelength routing algorithm which tries to avoid the multicast incapable
branching nodes (MIBs, branching nodes without splitting capability) in the
shortest-path-based multicast tree to diminish the link stress. Good parts of
the shortest-path-tree are retained by the algorithm to reduce the end-to-end
delay. The algorithm consists of tree steps: (1) aDijkstraPro algorithmwith
priority assignment and node adoption is introduced to produce a SPT with up to
38% fewer MIB nodes in the NSF topology and 46% fewerMIB nodes in the USA
Longhaul topology, (2) critical articulation and deepest branch heuristics are
used to process the MIB nodes, (3) a distance-based light-tree reconnection
algorithm is proposed to create the multicast light-trees. Extensive
simulations demonstrate the algorithm's efficiency in terms of link stress and
end-to-end delay
The Casimir force and the quantum theory of lossy optical cavities
We present a new derivation of the Casimir force between two parallel plane
mirrors at zero temperature. The two mirrors and the cavity they enclose are
treated as quantum optical networks. They are in general lossy and
characterized by frequency dependent reflection amplitudes. The additional
fluctuations accompanying losses are deduced from expressions of the optical
theorem. A general proof is given for the theorem relating the spectral density
inside the cavity to the reflection amplitudes seen by the inner fields. This
density determines the vacuum radiation pressure and, therefore, the Casimir
force. The force is obtained as an integral over the real frequencies,
including the contribution of evanescent waves besides that of ordinary waves,
and, then, as an integral over imaginary frequencies. The demonstration relies
only on general properties obeyed by real mirrors which also enforce general
constraints for the variation of the Casimir force.Comment: 18 pages, 6 figures, minor amendment
Direct Measurements of the Branching Fractions for and and Determinations of the Form Factors and
The absolute branching fractions for the decays and
are determined using singly
tagged sample from the data collected around 3.773 GeV with the
BES-II detector at the BEPC. In the system recoiling against the singly tagged
meson, events for and events for decays are observed. Those yield
the absolute branching fractions to be and . The
vector form factors are determined to be
and . The ratio of the two form
factors is measured to be .Comment: 6 pages, 5 figure
Measurements of J/psi Decays into 2(pi+pi-)eta and 3(pi+pi-)eta
Based on a sample of 5.8X 10^7 J/psi events taken with the BESII detector,
the branching fractions of J/psi--> 2(pi+pi-)eta and J/psi-->3(pi+pi-)eta are
measured for the first time to be (2.26+-0.08+-0.27)X10^{-3} and
(7.24+-0.96+-1.11)X10^{-4}, respectively.Comment: 11 pages, 6 figure
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