159 research outputs found
Oriented gap opening in the magnetically ordered state of Iron-pnicitides: an impact of intrinsic unit cell doubling on the square lattice by atoms
We show that the complicated band reconstruction near Fermi surfaces in the
magnetically ordered state of iron-pnictides observed by angle-resolved
photoemission spectroscopies (ARPES) can be understood in a meanfield level if
the \emph{intrinsic unit cell doubling} due to As atoms is properly considered
as shown in the recently constructed S microscopic effective model. The
(0,) or (,0) col-linear antiferromagnetic (C-AFM) order does not open
gaps between two points at Fermi surfaces linked by the ordered wave vector but
forces a band reconstruction involving four points in unfolded Brillouin zone
(BZ) and gives rise to small pockets or hot spots. The S symmetry naturally
chooses a staggered orbital order over a ferro-orbital order to coexist with
the C-AFM order. These results strongly suggest that the kinematics based on
the S symmetry captures the essential low energy physics of iron-based
superconductors.Comment: 5 figures, 5 page
THE ADVANTAGE OF GENETIC ALGORITHM IN ENERGY-EFFICIENT SCHEDULING FOR HETEROGENEOUS CLOUD COMPUTING
Nowadays Energy Consumption has been a heavy burden on the enterprise cloud computing infrastructure. This paper focuses on the hardware factors in energy consumption. Inspired by DVFS, it proposes a new energy-efficient (EE) model. This paper formulates the scheduling problem and genetic algorithm is applied to obtain higher efficiency value. Simulations are implemented to verify the advantage of genetic algorithm. In addition, the robustness of our strategy is validated by modifying the relevant parameters of the experimen
Quantum Hall Effects in a Non-Abelian Honeycomb Lattice
We study the tunable quantum Hall effects in a non-Abelian honeycomb optical
lattice which is a many-Dirac-points system. We find that the quantum Hall
effects present different features as change as relative strengths of several
perturbations. Namely, a gauge-field-dressed next-nearest-neighbor hopping can
induce the quantum spin Hall effect and a Zeeman field can induce a so-called
quantum anomalous valley Hall effect which includes two copies of quantum Hall
states with opposite Chern numbers and counter-propagating edge states. Our
study extends the borders of the field of quantum Hall effects in honeycomb
optical lattice when the internal valley degrees of freedom enlarge.Comment: 7 pages, 6 figure
Channel waveguides preserving luminescence features in Nd3+:Y2O3 ceramics produced by ultrafast laser inscription
We report on the Nd3+:Y2O3 ceramic optical channel waveguides produced by ultrafast laser inscription with a “double-line” scheme. The confocal micro-luminescence images reveal that the original fluorescence emission properties have not been affected by the laser filamentation, which means the original luminescence features have been well preserved in the waveguide volumes. The fabricated micro-photonic structures emerge as promising candidates for integrated laser sources.This work is supported by National Natural Science Foundation of China (10925524), Spanish Ministerio de Ciencia e Innovación through the Consolider Program SAUUL (CSD2007-00013) and Research project FIS2009-09522 by the Spanish Ministerio de Ciencia y Tecnología (MAT2007-64686) and CONICET (under project PIP 11220090100394)
Three novel α-L-iduronidase mutations in 10 unrelated Chinese mucopolysaccharidosis type I families
Mucopolysaccharidosis type I (MPS I) arises from a deficiency in the α-L-iduronidase (IDUA) enzyme. Although the clinical spectrum in MPS I patients is continuous, it was possible to recognize 3 phenotypes reflecting the severity of symptoms, viz., the Hurler, Scheie and Hurler/Scheie syndromes. In this study, 10 unrelated Chinese MPS I families (nine Hurler and one Hurler/Scheie) were investigated, and 16 mutant alleles were identified. Three novel mutations in IDUA genes, one missense p.R363H (c.1088G > A) and two splice-site mutations (c.1190-1G > A and c.792+1G > T), were found. Notably, 45% (nine out of 20) and 30% (six out of 20) of the mutant alleles in the 10 families studied were c.1190-1G > A and c.792+1G > T, respectively. The novel missense mutation p.R363H was transiently expressed in CHO cells, and showed retention of 2.3% IDUA activity. Neither p.W402X nor p.Q70X associated with the Hurler phenotype, or even p.R89Q associated with the Scheie phenotype, was found in this group. Finally, it was noted that the Chinese MPS I patients proved to be characterized with a unique set of IDUA gene mutations, not only entirely different from those encountered among Europeans and Americans, but also apparently not even the same as those found in other Asian countries
Direct Observationof DegenerateTwo-Photon Absorption and Its Saturation in WS2 and MoS2 Monolayer and Few-Layer Films
The optical nonlinearity of WS2, MoS2 monolayer and few-layer films was
investigated using the Z-scan technique with femtosecond pulses from the
visible to the near infrared. The dependence of nonlinear absorption of the WS2
and MoS2 films on layer number and excitation wavelength was studied
systematically. WS2 with 1~3 layers exhibits a giant two-photon absorption
(TPA) coefficient. Saturation of TPA for WS2 with 1~3 layers and MoS2 with
25~27 layers was observed. The giant nonlinearity of WS2 and MoS2 is attributed
to two dimensional confinement, a giant exciton effect and the band edge
resonance of TPA
Giant Two-Photon Absorption in Monolayer MoS2
Strong two-photon absorption (TPA) in monolayer MoS2 is demonstrated in
contrast to saturable absorption (SA) in multilayer MoS2 under the excitation
of femtosecond laser pulses in the near infrared region. MoS2 in the forms of
monolayer single crystal and multilayer triangular islands are grown on either
quartz or SiO2/Si by employing the seeding method through chemistry vapor
deposition. The nonlinear transmission measurements reveal that monolayer MoS2
possesses a giant nonsaturation TPA coefficient, larger than that of
conventional semiconductors. As a result of TPA, two-photon pumped frequency
up-converted luminescence is observed directly in the monolayer MoS2. For the
multilayer MoS2, the SA response is demonstrated with the ratio of the
excited-state absorption cross section to ground-state cross section of 0.18.
In addition, the laser damage threshold of the monolayer MoS2 is 97 GW/cm2,
larger than that of the multilayer MoS2 of 78 GW/cm2
Transpositional reactivation of the Dart transposon family in rice lines derived from introgressive hybridization with Zizania latifolia
<p>Abstract</p> <p>Background</p> <p>It is widely recognized that interspecific hybridization may induce "genome shock", and lead to genetic and epigenetic instabilities in the resultant hybrids and/or backcrossed introgressants. A prominent component involved in the genome shock is reactivation of cryptic transposable elements (TEs) in the hybrid genome, which is often associated with alteration in the elements' epigenetic modifications like cytosine DNA methylation. We have previously reported that introgressants derived from hybridization between <it>Oryza sativa </it>(rice) and <it>Zizania latifolia </it>manifested substantial methylation re-patterning and rampant mobilization of two TEs, a <it>copia </it>retrotransposon <it>Tos17 </it>and a MITE <it>mPing</it>. It was not known however whether other types of TEs had also been transpositionally reactivated in these introgressants, their relevance to alteration in cytosine methylation, and their impact on expression of adjacent cellular genes.</p> <p>Results</p> <p>We document in this study that the <it>Dart </it>TE family was transpositionally reactivated followed by stabilization in all three studied introgressants (RZ1, RZ2 and RZ35) derived from introgressive hybridization between rice (cv. Matsumae) and <it>Z. latifolia</it>, while the TEs remained quiescent in the recipient rice genome. Transposon-display (TD) and sequencing verified the element's mobility and mapped the excisions and re-insertions to the rice chromosomes. Methylation-sensitive Southern blotting showed that the <it>Dart </it>TEs were heavily methylated along their entire length, and moderate alteration in cytosine methylation patterns occurred in the introgressants relative to their rice parental line. Real-time qRT-PCR quantification on the relative transcript abundance of six single-copy genes flanking the newly excised or inserted <it>Dart</it>-related TE copies indicated that whereas marked difference in the expression of all four genes in both tissues (leaf and root) were detected between the introgressants and their rice parental line under both normal and various stress conditions, the difference showed little association with the presence or absence of the newly mobilized <it>Dart-</it>related TEs.</p> <p>Conclusion</p> <p>Introgressive hybridization has induced transpositional reactivation of the otherwise immobile <it>Dart</it>-related TEs in the parental rice line (cv. Matsumae), which was accompanied with a moderate alteration in the element's cytosine methylation. Significant difference in expression of the <it>Dart</it>-adjacent genes occurred between the introgressants and their rice parental line under both normal and various abiotic stress conditions, but the alteration in gene expression was not coupled with the TEs.</p
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