Luttinger Parameter g for Metallic Carbon Nanotubes and Related Systems

The random phase approximation (RPA) theory is used to derive the Luttinger parameter g for metallic carbon nanotubes. The results are consistent with the Tomonaga-Luttinger models. All metallic carbon nanotubes, regardless if they are armchair tubes, zigzag tubes, or chiral tubes, should have the same Luttinger parameter g. However, a (10,10) carbon peapod should have a smaller g value than a (10,10) carbon nanotube. Changing the Fermi level by applying a gate voltage has only a second order effect on the g value. RPA theory is a valid approach to calculate plasmon energy in carbon nanotube systems, regardless if the ground state is a Luttinger liquid or Fermi liquid. (This paper was published in PRB 66, 193405 (2002). However, Eqs. (6), (9), and (19) were misprinted there.)Comment: 2 figure

Scale Effect of Premixed Methane-Air Combustion in Confined Space Using LES Model

Gas explosion is the most hazardous incident occurring in underground airways. Computational Fluid Dynamics (CFD) techniques are sophisticated in simulating explosions in confined spaces; specifically, when testing large-scale gaseous explosions, such as methane explosions in underground mines. The dimensions of a confined space where explosions could occur vary significantly. Thus, the scale effect on explosion parameters is worth investigating. In this paper, the impact of scaling on explosion overpressures is investigated by employing two scaling factors: The Gas-fill Length Scaling Factor (FLSF) and the Hydraulic Diameter Scaling Factor (HDSF). The combinations of eight FLSFs and five HDSFs will cover a wide range of space dimensions where flammable gas could accumulate. Experiments were also conducted to evaluate the selected numerical models. The Large Eddy Simulation turbulence model was selected because it shows accuracy compared to the widely used Reynolds\u27 averaged models for the scenarios investigated in the experiments. Three major conclusions can be drawn: (1) The overpressure increases with both FLSF and HDSF within the deflagration regime; (2) In an explosion duct with a length to diameter ratio greater than 54, detonation is more likely to be triggered for a stoichiometric methane/air mixture; (3) Overpressure increases as an increment hydraulic diameter of a geometry within deflagration regime. A relative error of 7% is found when predicting blast peak overpressure for the base case compared to the experiment; a good agreement for the wave arrival time is also achieved

Modeling of Geometric Change Influence on Blast-Wave Propagation in Underground Airways Using a 2D-Transient Euler Scheme

The impact of methane explosions on mining operations can never be over-emphasized. The safety of miners could be threatened and local ventilation facilities are likely to be damaged by the flame and overpressure induced by a methane explosion event, making it essential to understand the destructiveness and influence range of a specific explosion. In this paper, the attenuation effect of geometric changes, most commonly bends, obstacles, and branches, present in the way of blast-wave propagation and the capability of the selected numerical model were studied. Although some relevant experimental research has been provided, quantitative analysis is insufficient. This paper investigates the attenuation factors of seven bends, three obstacles, and two T-branch scenarios to ascertain a better insight of this potentially devastating event quantitatively. The results suggest that (1) the numerical model used is capable of predicting four of the seven validated scenarios with a relative error less than 12%; (2) the maximum peak overpressure is obtained when the angle equals 50° for bend cases; and (3) the selected numerical scheme would overestimate the obstacle cases by around 15%

Increased cocaine self-administration in rats lacking the serotonin transporter : a role for glutamatergic signaling in the habenula

Serotonin (5-HT) and the habenula (Hb) contribute to motivational and emotional states such as depression and drug abuse. The dorsal raphe nucleus, where 5-HT neurons originate, and the Hb are anatomically and reciprocally interconnected. Evidence exists that 5-HT influences Hb glutamatergic transmission. Using serotonin transporter knockout (SERT-/- ) rats, which show depression-like behavior and increased cocaine intake, we investigated the effect of SERT reduction on expression of genes involved in glutamate neurotransmission under both baseline conditions as well as after short-access or long-access cocaine (ShA and LgA, respectively) intake. In cocaine-na\uefve animals, SERT removal led to reduced baseline Hb mRNA levels of critical determinants of glutamate transmission, such as SLC1A2, the main glutamate transporter and N-methyl-D-aspartate (Grin1, Grin2A and Grin2B) as well as \u3b1-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (Gria1 and Gria2) receptor subunits, with no changes in the scaffolding protein Dlg4. In response to ShA and LgA cocaine intake, SLC1A2 and Grin1 mRNA levels decreased in SERT+/+ rats to levels equal of those of SERT-/- rats. Our data reveal that increased extracellular levels of 5-HT modulate glutamate neurotransmission in the Hb, serving as critical neurobiological substrate for vulnerability to cocaine addiction

F-E3D: FPGA-based acceleration of an efficient 3D convolutional neural network for human action recognition

Three-dimensional convolutional neural networks (3D CNNs) have demonstrated their outstanding classification accuracy for human action recognition (HAR). However, the large number of computations and parameters in 3D CNNs limits their deployability in real-life applications. To address this challenge, this paper adopts an algorithm-hardware co-design method by proposing an efficient 3D CNN building unit called 3D-1 bottleneck residual block (3D-1 BRB) at the algorithm level, and a corresponding FPGA-based hardware architecture called F-E3D at hardware level. Based on 3D-1 BRB, a novel 3D CNN model called E3DNet is developed, which achieves nearly 37 times reduction in model size and 5% improvement in accuracy compared to standard 3D CNNs on the UCF101 dataset. Together with several hardware optimizations, including 3D fused BRB, online blocking and kernel reuse, the proposed F-E3D is nearly 13 times faster than a previous FPGA design for 3D CNNs, with performance and accuracy comparable to other state-of-the-art 3D CNN models on GPU platforms while requiring only 7% of their energy consumption

A view of transcriptome during cold stress in sugarcane using Saccharum spontaneum genome

Transcriptomic data of two sugarcane cultivars ‘ROC22’ and ‘GT08-1108’ were investigated for the expression analysis of cold responsive genes. The raw RNA Seq data of the sugarcane cultivars were downloaded from the SRA NCBI database and were reanalyzed and mapped by using Saccharum spontaneum genome.  In the Saccharum spontaneum reference genome, 83826 unigenes were annotated and, among these, 46,159 (55%) were functionally annotated with Gene Ontology (GO) categories. In the transcriptome-based analysis, 183,515 unigenes were assembled and, among these, 110,021 (60%) were functionally annotated with GO categories. For the cultivar GT08-1108, using the reference genome pipeline, 11,652 (13.9%) unigenes were differentially expressed (7,238 upregulated; 4,414 downregulated), while 16,145 (8.8%) were differentially expressed (8,965 upregulated; 7,180 downregulated) using transcriptome-based pipeline. In the cultivar ROC22, 11,516 (13.7%) genes were differentially expressed (7,174 upregulated; 4,342 downregulated) and 20,317 (11.1%) (10,898 upregulated; 9,419 downregulated) for the genome and transcriptome-based analysis, respectively. In the genome analyses, among downregulated genes, 3,248 were coincident between the two cultivars, the remaining 1,166 differentially expressed only in ‘GT-1180’ and 1,094 only in ‘ROC22’. With the transcriptome assembly, 13,113 genes were deferentially expressed in both cultivars, the remaining 3,032 unique to ‘GT08-1108’ and 7,204 in ‘ROC22’. We concluded that sugarcane in response to cold stress expresses many genes, although the transcriptome assembly overestimated the number of unigenes and, consequently, a higher number of differentially expressed genes. This may be due to difficulties in separating homeologues from paralogue genes. When a reference genome is available, we recommend its use since genes predicted on a reference genome tend to be more accurate

Far-infrared absorption in parallel quantum wires with weak tunneling

We study collective and single-particle intersubband excitations in a system of quantum wires coupled via weak tunneling. For an isolated wire with parabolic confinement, the Kohn's theorem guarantees that the absorption spectrum represents a single sharp peak centered at the frequency given by the bare confining potential. We show that the effect of weak tunneling between two parabolic quantum wires is twofold: (i) additional peaks corresponding to single-particle excitations appear in the absorption spectrum, and (ii) the main absorption peak acquires a depolarization shift. We also show that the interplay between tunneling and weak perpendicular magnetic field drastically enhances the dispersion of single-particle excitations. The latter leads to a strong damping of the intersubband plasmon for magnetic fields exceeding a critical value.Comment: 18 pages + 6 postcript figure

Crystal chemistry and electronic structure of the β-AlFeSi phase from first-principles

Supplementary data are available online at https://www.sciencedirect.com/science/article/pii/S0022459621002449?via%3Dihub#appsec1 .β-AlFeSi has a layered structure composed of FeAlSi blocks and exhibits a rich variety of crystal chemistry. Plate-like/rod-like β-AlFeSi particles formed in Al-based alloys have nontrivial influences on the mechanical performance of the cast parts. Here, we investigate the stability, crystal chemistry and electronic structure of the β-phase using the first-principles density-functional theory (DFT) method. We reveal that Si prefers on the Al1 or Al6 sites, forming stable β-Al4.5SiIFe or β-Al4.5SiVIFe (the Roman numerals represent the Al sites in the Rømming’s labels). This differs from the existing model with a homogeneous Si/Al distribution. Moreover, the calculations also find that stacking of the FeAlSi blocks leads to structural transformations. Electronically β-Al4.5SiFe is anisotropic with a narrow pseudo-band-gap, indicating its unusual physical properties. The obtained information here sheds some light not only on the stability and crystal chemistry of the β-phase as a member of the large family of the Fe-containing intermetallic compounds in Al-based alloys, but also on its potential applications as low-dimensional functional materials.EPSRC (UK) under grant numbers EP/N007638/1 and EP/S005102/1

Two novel transcriptional regulators are essential for infection-related morphogenesis and pathogenicity of the rice blast fungus Magnaporthe oryzae.

This is the final version of the article. Available from the publisher via the DOI in this record.The cyclic AMP-dependent protein kinase A signaling pathway plays a major role in regulating plant infection by the rice blast fungus Magnaporthe oryzae. Here, we report the identification of two novel genes, MoSOM1 and MoCDTF1, which were discovered in an insertional mutagenesis screen for non-pathogenic mutants of M. oryzae. MoSOM1 or MoCDTF1 are both necessary for development of spores and appressoria by M. oryzae and play roles in cell wall differentiation, regulating melanin pigmentation and cell surface hydrophobicity during spore formation. MoSom1 strongly interacts with MoStu1 (Mstu1), an APSES transcription factor protein, and with MoCdtf1, while also interacting more weakly with the catalytic subunit of protein kinase A (CpkA) in yeast two hybrid assays. Furthermore, the expression levels of MoSOM1 and MoCDTF1 were significantly reduced in both Δmac1 and ΔcpkA mutants, consistent with regulation by the cAMP/PKA signaling pathway. MoSom1-GFP and MoCdtf1-GFP fusion proteins localized to the nucleus of fungal cells. Site-directed mutagenesis confirmed that nuclear localization signal sequences in MoSom1 and MoCdtf1 are essential for their sub-cellular localization and biological functions. Transcriptional profiling revealed major changes in gene expression associated with loss of MoSOM1 during infection-related development. We conclude that MoSom1 and MoCdtf1 functions downstream of the cAMP/PKA signaling pathway and are novel transcriptional regulators associated with cellular differentiation during plant infection by the rice blast fungus.Funding: This work was supported by National Key Basic Research and Development Program of China (2012CB114002), by Program for Changjiang Scholars and Innovative Research Team in University (IRT0943), by the Natural Science Foundation of China (Grant Nos. 30970129 and 31071648) and the Doctoral Fund of Ministry of Education of China (20100101110097) to ZW