11,477 research outputs found
An Optimal Algorithm for the Maximum-Density Segment Problem
We address a fundamental problem arising from analysis of biomolecular
sequences. The input consists of two numbers and and a
sequence of number pairs with . Let {\em segment}
of be the consecutive subsequence of between indices and
. The {\em density} of is
. The {\em maximum-density
segment problem} is to find a maximum-density segment over all segments
with . The best
previously known algorithm for the problem, due to Goldwasser, Kao, and Lu,
runs in time. In the present paper, we solve
the problem in O(n) time. Our approach bypasses the complicated {\em right-skew
decomposition}, introduced by Lin, Jiang, and Chao. As a result, our algorithm
has the capability to process the input sequence in an online manner, which is
an important feature for dealing with genome-scale sequences. Moreover, for a
type of input sequences representable in space, we show how to
exploit the sparsity of and solve the maximum-density segment problem for
in time.Comment: 15 pages, 12 figures, an early version of this paper was presented at
11th Annual European Symposium on Algorithms (ESA 2003), Budapest, Hungary,
September 15-20, 200
Fire responses and resistance of concrete-filled steel tubular frame structures
This paper presents the results of dynamic responses and fire resistance of concretefilled
steel tubular (CFST) frame structures in fire conditions by using non-linear finite element
method. Both strength and stability criteria are considered in the collapse analysis. The frame
structures are constructed with circular CFST columns and steel beams of I-sections. In order to
validate the finite element solutions, the numerical results are compared with those from a fire
resistance test on CFST columns. The finite element model is then adopted to simulate the
behaviour of frame structures in fire. The structural responses of the frames, including critical
temperature and fire-resisting limit time, are obtained for the ISO-834 standard fire. Parametric
studies are carried out to show their influence on the load capacity of the frame structures in fire.
Suggestions and recommendations are presented for possible adoption in future construction and
design of these structures
Relative entropy of entanglement of a kind of two qubit entangled states
We in this paper strictly prove that some block diagonalizable two qubit
entangled state with six none zero elements reaches its quantum relative
entropy entanglement by the a separable state having the same matrix structure.
The entangled state comprises local filtering result state as a special case.Comment: 5 page
ROS signaling and its involvement in abiotic stress with emphasis on heat stress-driven anther sterility in plants
ROS signaling and its involvement in abiotic stress with emphasis on heat stress-driven anther sterility in plants, Crop and Environment, https://doi. Abstract 12 With global warming, crop plants are challenged by heat stress during reproductive growth, 13 leading to male sterility and yield reduction. The balance between reactive oxygen species (ROS) 14 generation and scavenging is disrupted by stress, resulting in oxidative stress, which is harmful to 15 crop growth. However, recent advances have shown that ROS signaling via proteins that sense the 16 redox state is positive for plant performance under stress. ROS signaling is also involved in 17 regulating anther development, such as timely tapetum degeneration. We summarize recent progress 18 in uncovering the mechanism of heat stress effects on ROS homeostasis and discuss the relationship 19 between oxidative stress and metabolic disorder, which is often observed during anther development 20 under heat stress. We propose experimental and breeding strategies to improve field crop tolerance 21 to heat stress. 2
Neutrino oscillations in Kerr-Newman space-time
The mass neutrino oscillation in Kerr-Newman(K-N) space-time is studied in
the plane , and the general equations of oscillation phases
are given. The effect of the rotation and electric charge on the phase is
presented. Then, we consider three special cases: (1) The neutrinos travel
along the geodesics with the angular momentum in the equatorial plane.
(2) The neutrinos travel along the geodesics with L=0 in the equatorial plane.
(3) The neutrinos travel along the radial geodesics at the direction
. At last, we calculate the proper oscillation length in the K-N
space time. The effect of the gravitational field on the oscillation length is
embodied in the gravitational red shift factor. When the neutrino travels out
of the gravitational field, the blue shift of the oscillation length takes
place. We discussed the variation of the oscillation length influenced by the
gravitational field strength, the rotation and charge .Comment: 20 pages, no figure
Magnetization and Magnetotransport of LnBaCo2O5.5 (Ln=Gd, Eu) Single Crystals
The magnetization, resistivity and magnetoresistance (MR) of single crystals
of GdBaCo2O5.5 and EuBaCo2O5.5 are measured over a wide range of dc magnetic
fields (up to 30 T) and temperature. In LnBaCo2O5.5 (Ln=Gd, Eu), the Co-ions
are trivalent and can exist in three spin states, namely, the S=0 low spin
state (LS), the S= 1 intermediate spin state (IS) and the S=2 high spin state
(HS). We confirm that GdBaCo2O5.5 and EuBaCo2O5.5 have a metal-insulator
transition accompanied by a spin-state transition at TMI >> 365 and 335 K,
respectively. The data suggest an equal ratio of LS (S=0) and IS (S=1) Co3+
ions below TMI, with no indication of additional spin state transitions. The
low field magnetization shows a transition to a highly anisotropic
ferromagnetic phase at 270 K, followed by another magnetic transition to an
antiferromagnetic phase at a slightly lower temperature. The magnetization data
are suggestive of weak correlations between the Gd-spins but no clear signature
of ordering is seen for T > 2 K. Significant anisotropy between the a-b plane
and c axis was observed in magnetic and magnetotransport properties for both
compounds. For GdBaCo2O5.5, the resistivity and MR data imply a strong
correlation between the spin-order and charge carriers. For EuBaCo2O5.5, the
magnetic phase diagram is very similar to its Gd counterpart, but the low-T MR
with current flow in the ab plane is positive rather than negative as for Gd.
The magnitude and the hysteresis of the MR for EuBaCo2O5.5 decrease with
increasing temperature, and at higher T the MR changes sign and becomes
negative. The difference in the behavior of both compounds may arise from a
small valence admixture in the nonmagnetic Eu ions, i.e. a valence slightly
less than 3+.Comment: Accepted for publication in PR
Hall Drag in Correlated Double Layer Quantum Hall Systems
We show that in the limit of zero temperature, double layer quantum Hall
systems exhibit a novel phenomena called Hall drag, namely a current driven in
one layer induces a voltage drop in the other layer, in the direction
perpendicular to the driving current. The two-by-two Hall resistivity tensor is
quantized and proportional to the matrix that describes the
topological order of the quantum Hall state, even when the matrix
contains a zero eigenvalue, in which case the Hall conductivity tensor does not
exist. Relation between the present work and previous ones is also discussed.Comment: 4 pages, 1 eps figure. Accepted in PRB, R
Advances on the Antioxidant Peptides from Nuts: A Narrow Review
Antioxidant peptides extracted from natural foods have been studied for their potential use in the development of additives, nutraceuticals, and therapeutic agents. Nut proteins are considered an excellent source of plant-derived proteins for the human diet, due to their high protein content and digestibility of up to 86.22%. Furthermore, compared with grain and soybean proteins, nut proteins have a special amino acid composition, which makes their protein structure different, and promotes their disparate functional characteristics and great bioactivity potential. This review presents the most remarkable studies on antioxidant peptides from nuts, to gain insights into feasible production methods, different evaluation indexes within in vivo or in vitro systems, high bioavailability, and the complex structure-activity relationship resulting from the particularity of their protein structure and amino acid composition. Previously published studies mainly focused on the effects of the production methods/processes of nut-derived peptides on antioxidant activity, and proved that nut-extracted antioxidant peptides can resist the degradation of acid, alkali, and gastrointestinal enzymes, have high antioxidant activity in vitro and in vivo, and also have the potential to cross small intestinal epithelial cells in a stable and integral manner. However, the structure-activity relationship of antioxidant peptides from nuts has not been fully established, and the structure information of antioxidant peptides obtained from various nut protein sources is still unclear. The findings presented in this review can be used to provide the theoretical basis for the design and production of nut-derived antioxidant peptides
Measurement of the final states , , and from \psip electromagnetic decays and \ee annihilations
Cross sections and form factors for \ee \to \wpi, , and
\rho\etap at center of mass energies of 3.650, 3.686, and 3.773 GeV are
measured using data samples collected with the BESII detector at the BEPC.
Also, the branching fractions of \psi(2S) \rar \wpi, , and
\rho\etap are determined to be ,
, and
, respectively.Comment: 8 pages, 4 figures, 4 table
The Quantum Spin Hall Effect: Theory and Experiment
The search for topologically non-trivial states of matter has become an
important goal for condensed matter physics. Recently, a new class of
topological insulators has been proposed. These topological insulators have an
insulating gap in the bulk, but have topologically protected edge states due to
the time reversal symmetry. In two dimensions the helical edge states give rise
to the quantum spin Hall (QSH) effect, in the absence of any external magnetic
field. Here we review a recent theory which predicts that the QSH state can be
realized in HgTe/CdTe semiconductor quantum wells. By varying the thickness of
the quantum well, the band structure changes from a normal to an "inverted"
type at a critical thickness . We present an analytical solution of the
helical edge states and explicitly demonstrate their topological stability. We
also review the recent experimental observation of the QSH state in
HgTe/(Hg,Cd)Te quantum wells. We review both the fabrication of the sample and
the experimental setup. For thin quantum wells with well width
nm, the insulating regime shows the conventional behavior of vanishingly small
conductance at low temperature. However, for thicker quantum wells ( nm), the nominally insulating regime shows a plateau of residual
conductance close to . The residual conductance is independent of the
sample width, indicating that it is caused by edge states. Furthermore, the
residual conductance is destroyed by a small external magnetic field. The
quantum phase transition at the critical thickness, nm, is also
independently determined from the occurrence of a magnetic field induced
insulator to metal transition.Comment: Invited review article for special issue of JPSJ, 32 pages. For
higher resolution figures see official online version when publishe
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