3,743 research outputs found
Cognitive Multihop Wireless Sensor Networks over Nakagami-m Fading Channels
This work is supported by the National Science Foundation of China (NSFC) under Grant 61372114, by the National 973 Program of China under Grant 2012CB316005, by the Joint Funds of NSFC-Guangdong under Grant U1035001, and by Beijing Higher Education Young Elite Teacher Project (no. YETP0434)
Mapping between dissipative and Hamiltonian systems
Theoretical studies of nonequilibrium systems are complicated by the lack of
a general framework. In this work we first show that a transformation
introduced by Ao recently (J. Phys. A {\bf 37}, L25 (2004)) is related to
previous works of Graham (Z. Physik B {\bf 26}, 397 (1977)) and Eyink {\it et
al.} (J. Stat. Phys. {\bf 83}, 385 (1996)), which can also be viewed as the
generalized application of the Helmholtz theorem in vector calculus. We then
show that systems described by ordinary stochastic differential equations with
white noise can be mapped to thermostated Hamiltonian systems. A steady-state
of a dissipative system corresponds to the equilibrium state of the
corresponding Hamiltonian system. These results provides a solid theoretical
ground for corresponding studies on nonequilibrium dynamics, especially on
nonequilibrium steady state. The mapping permits the application of established
techniques and results for Hamiltonian systems to dissipative non-Hamiltonian
systems, those for thermodynamic equilibrium states to nonequilibrium steady
states. We discuss several implications of the present work.Comment: 18 pages, no figure. final version for publication on J. Phys. A:
Math & Theo
The components of empirical multifractality in financial returns
We perform a systematic investigation on the components of the empirical
multifractality of financial returns using the daily data of Dow Jones
Industrial Average from 26 May 1896 to 27 April 2007 as an example. The
temporal structure and fat-tailed distribution of the returns are considered as
possible influence factors. The multifractal spectrum of the original return
series is compared with those of four kinds of surrogate data: (1) shuffled
data that contain no temporal correlation but have the same distribution, (2)
surrogate data in which any nonlinear correlation is removed but the
distribution and linear correlation are preserved, (3) surrogate data in which
large positive and negative returns are replaced with small values, and (4)
surrogate data generated from alternative fat-tailed distributions with the
temporal correlation preserved. We find that all these factors have influence
on the multifractal spectrum. We also find that the temporal structure (linear
or nonlinear) has minor impact on the singularity width of the
multifractal spectrum while the fat tails have major impact on ,
which confirms the earlier results. In addition, the linear correlation is
found to have only a horizontal translation effect on the multifractal spectrum
in which the distance is approximately equal to the difference between its DFA
scaling exponent and 0.5. Our method can also be applied to other financial or
physical variables and other multifractal formalisms.Comment: 6 epl page
Implications of texture 4 zero lepton mass matrices for U_{e3}
Lepton mass matrices similar to texture 4 zero quark mass matrices, known to
be quite successful in explaining the CKM phenomenology, have been considered
for finding the mixing matrix element U_{e3} (\equiv s_{13}) respecting the
CHOOZ constraint, with s_{12} and \Delta m_{12}^2 constrained by SNP and s_{23}
and \Delta m_{23}^2 constrained by ANP. Taking charged lepton mass matrix M_l
to be diagonal, we find that the ranges of s_{13} corresponding to different
SNP solutions very well include the corresponding values of s_{13} found by
Akhmedov et al. by considering neutrino mass matrix M_{\nu} with no texture
zeros. Considering M_l and M_{\nu} both to be real and non-diagonal, s_{13}
ranges for the four SNP solutions come out to be: \sim 0-0.19 (LMA),
0.038-0.093 (SMA), 0.042-0.095 (LOW), 0.038-0.096 (VO) which remain of the same
order when M_l and M_{\nu} are considered to be complex and non-diagonal.Comment: 13 pages, LaTe
Proteomic profile of KSR1-regulated signalling in response to genotoxic agents in breast cancer
Kinase suppressor of Ras 1 (KSR1) has been implicated in tumorigenesis in multiple cancers, including skin, pancreatic and lung carcinomas. However, our recent study revealed a role of KSR1 as a tumour suppressor in breast cancer, the expression of which is potentially correlated with chemotherapy response. Here, we aimed to further elucidate the KSR1-regulated signalling in response to genotoxic agents in breast cancer. Stable isotope labelling by amino acids in cell culture (SILAC) coupled to high-resolution mass spectrometry (MS) was implemented to globally characterise cellular protein levels induced by KSR1 in the presence of doxorubicin or etoposide. The acquired proteomic signature was compared and GO-STRING analysis was subsequently performed to illustrate the activated functional signalling networks. Furthermore, the clinical associations of KSR1 with identified targets and their relevance in chemotherapy response were examined in breast cancer patients. We reveal a comprehensive repertoire of thousands of proteins identified in each dataset and compare the unique proteomic profiles as well as functional connections modulated by KSR1 after doxorubicin (Doxo-KSR1) or etoposide (Etop-KSR1) stimulus. From the up-regulated top hits, several proteins, including STAT1, ISG15 and TAP1 are also found to be positively associated with KSR1 expression in patient samples. Moreover, high KSR1 expression, as well as high abundance of these proteins, is correlated with better survival in breast cancer patients who underwent chemotherapy. In aggregate, our data exemplify a broad functional network conferred by KSR1 with genotoxic agents and highlight its implication in predicting chemotherapy response in breast cancer
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Optimizing mechanical properties of Fe26.7Co26.7Ni26.7Si8.9B11 high entropy alloy by inducing hypoeutectic to quasi-duplex microstructural transition
High-entropy alloys (HEAs) have inspired considerable interest due to their attractive physical and mechanical properties. In this work, the microstructural evolution induced by different heat treatments on rapidly solidified hypoeutectic precursors of a Fe26.7Co26.7Ni26.7Si8.9B11 HEA is investigated and correlated with the corresponding mechanical properties. The microstructures of the rapidly solidified precursors are composed of primary fcc solid solution dendrites embedded in a eutectic matrix. When the samples are annealed at different temperatures after furnace cooling or quenching, respectively, the eutectic structure gradually decomposes into fcc, tetragonal (Fe,Co)2B, and hexagonal Ni31Si12 crystals with increasing annealing temperature, leading to a gradual increase of the content of the fcc crystals and both their aggregation and coarsening. Then the dominant structural framework gradually transforms from eutectic structures to fcc dendrites and ultimately the (Fe,Co)2B crystals become isolated as dominant reinforcement particles distributed in the interdendritic regions. This gradual microstructural transition from hypoeutectic to quasi-duplex structures leads to the change of the dominant deformation mechanism from crack-controlled to dislocation-dominated deformation, which allows to control both ductility and strength in a wide range. Hence, this study provides some guideline for how to tune the microstructure and mechanical properties of HEAs
Effective electro-optical modulation with high extinction ratio by a graphene-silicon microring resonator
Graphene opens up for novel optoelectronic applications thanks to its high
carrier mobility, ultra-large absorption bandwidth, and extremely fast material
response. In particular, the opportunity to control optoelectronic properties
through tuning of Fermi level enables electro-optical modulation,
optical-optical switching, and other optoelectronics applications. However,
achieving a high modulation depth remains a challenge because of the modest
graphene-light interaction in the graphene-silicon devices, typically,
utilizing only a monolayer or few layers of graphene. Here, we comprehensively
study the interaction between graphene and a microring resonator, and its
influence on the optical modulation depth. We demonstrate graphene-silicon
microring devices showing a high modulation depth of 12.5 dB with a relatively
low bias voltage of 8.8 V. On-off electro-optical switching with an extinction
ratio of 3.8 dB is successfully demonstrated by applying a square-waveform with
a 4 V peak-to-peak voltage.Comment: 12 pages, including 7 figure
Quark masses and mixings in the RS1 model with a condensing 4th generation
We study the hierarchy of quark masses and mixings in a model based on a
5-dimensional spacetime with constant curvature of Randall-Sundrum type with
two branes, where the Electroweak Symmetry Breaking is caused dynamically by
the condensation of a 4th generation of quarks, due to underlying physics from
the 5D bulk and the first KK gluons. We first study the hierarchy of quark
masses and mixings that can be obtained from purely adjusting the profile
localizations, finding that realistic masses are not reproduced unless non
trivial hierarchies of underlying 4-fermion interactions from the bulk are
included. Then we study global U(1) symmetries that can be imposed in order to
obtain non-symmetric modified Fritzsch-like textures in the mass matrices that
reproduce reasonably well quark masses and CKM mixings.Comment: Minor changes. Version accepted for publication in JHE
Determination of the Michel Parameters and the tau Neutrino Helicity in tau Decay
Using the CLEO II detector at the storage ring CESR, we have
determined the Michel parameters , , and in decay as well as the tau neutrino helicity parameter
in decay. From a data sample of
tau pairs produced at , using events of
the topology and , and the determined sign of , the combined
result of the three samples is: , , , and
. The results are in agreement with
the Standard Model V-A interaction.Comment: 18 page postscript file, postscript file also available through
http://w4.lns.cornell.edu/public/CLN
Measurement of the Inclusive Semi-electronic Branching Fraction
Using the angular correlation between the emitted in a decay and the emitted in the subsequent decay, we have measured the branching fraction for the
inclusive semi-electronic decay of the meson to be: {\cal B}(D^0
\rightarrow X e^+ \nu) = [6.64 \pm 0.18 (stat.) \pm 0.29 (syst.)] \%. The
result is based on 1.7 fb of collisions recorded by the CLEO II
detector located at the Cornell Electron Storage Ring (CESR). Combining the
analysis presented in this paper with previous CLEO results we find,
\frac{{\cal B} (D^0 \rightarrow X e^+ \nu)}
{{\cal B} (D^0 \rightarrow K^- \pi^+)}
= 1.684 \pm 0.056 (stat.) \pm 0.093(syst.) and
\frac{{\cal B}(D\rightarrow K^-e^+\nu)}
{{\cal B}(D\rightarrow Xe^+\nu)}
= 0.581 \pm 0.023 (stat.) \pm 0.028(syst.).
The difference between the inclusive rate and the sum of the measured
exclusive branching fractions (measured at CLEO and other experiments) is of the inclusive rate.Comment: Latex file, 33pages, 4 figures Submitted to PR
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