Dissipationless Anomalous Hall Current in Fe100−x(SiO2)xFe_{100-x}(SiO_2)_x Films

The observation of dissipationless anomalous Hall current is one of the experimental evidences to confirm the intrinsic origin of anomalous Hall effect. To study the origin of anomalous Hall effect in iron, Fe$_{100-x}$(SiO$_{2}$)$_{x}$ granular films with volume fraction of SiO$_{2}$ 0\le x \le 40.51 were fabricated using co-sputtering. Hall and longitudinal resistivities were measured in the temperature range 5 to 350 K with magnetic fields up to 5 Tesla. As x increased from 0 to 40.51, the anomalous Hall resistivity and longitudinal resistivity increased about 4 and 3 orders in magnitude, respectively. Analysis of the results revealed that the normalized anomalous Hall conductivity is a constant for all the samples, the evidence of dissipationless anomalous Hall current in Fe.Comment: 17 pages, 5 figures; http://link.aps.org/doi/10.1103/PhysRevB.83.20531

Fermi resonance-algebraic model for molecular vibrational spectra

A Fermi resonance-algebraic model is proposed for molecular vibrations, where a U(2) algebra is used for describing the vibrations of each bond, and Fermi resonances between stretching and bending modes are taken into account. The model for a bent molecule XY_2 and a molecule XY_3 is successfully applied to fit the recently observed vibrational spectrum of the water molecule and arsine (AsH_3), respectively, and results are compared with those of other models. Calculations show that algebraic approaches can be used as an effective method for describing molecular vibrations with small standard deviations

Stochastic assembly in a subtropical forest chronosequence: evidence from contrasting changes of species, phylogenetic and functional dissimilarity over succession

This is the final version. Available on open access from Springer Verlag via the DOI in this recordDeterministic and stochastic processes jointly determine the community dynamics of forest succession. However, it has been widely held in previous studies that deterministic processes dominate forest succession. Furthermore, inference of mechanisms for community assembly may be misleading if based on a single axis of diversity alone. In this study, we evaluated the relative roles of deterministic and stochastic processes along a disturbance gradient by integrating species, functional, and phylogenetic beta diversity in a subtropical forest chronosequence in Southeastern China. We found a general pattern of increasing species turnover, but little-to-no change in phylogenetic and functional turnover over succession at two spatial scales. Meanwhile, the phylogenetic and functional beta diversity were not significantly different from random expectation. This result suggested a dominance of stochastic assembly, contrary to the general expectation that deterministic processes dominate forest succession. On the other hand, we found significant interactions of environment and disturbance and limited evidence for significant deviations of phylogenetic or functional turnover from random expectations for different size classes. This result provided weak evidence of deterministic processes over succession. Stochastic assembly of forest succession suggests that post-disturbance restoration may be largely unpredictable and difficult to control in subtropical forests.This study was supported financially by National Key Research and Development Project of China (2016YFC0500202) the National Natural Science Foundation of China (31170401), and the Earthwatch Institute program “Quantify and monitor carbon pools and fluxes to assess the impact of climate change on subtropical forests under different anthropogenic disturbances”. NGS was supported by two NSF USA-China Dimensions of Biodiversity Grants (DEB - 1046113; DEB - 1241136)

In situ high speed imaging study and modelling of the fatigue fragmentation of dendritic structures in ultrasonic fields

The fatigue fragmentation of dendritic structures of a SCN-5wt.% Camphor transparent alloy in an ultrasound field was investigated systematically using high-speed imaging. Dynamic interactions between oscillating ultrasonic bubbles and the primary and secondary dendrites were observed and recorded. High speed images show that when an ultrasound bubble was trapped inside an interdendritic region, the oscillation of the bubble can cause cyclic bending of the dendritic arms. Consequently, a fatigue type crack initiated at the arm root and propagated through the dendrite, causing the dendrite to fragment, i.e. dendritic fragmentation. From the recorded videos, the cycle numbers for the fatigue fragmentation were extracted, then, the fatigue strength and fatigue life of the SCN-5wt.% Camphor transparent alloy were calculated. Results showed that the cyclic fatigue load cause a crack initiating on a SCN dendrite at a much lower stress level than its tensile strength under high frequent oscillation

On the preparation of single crystals of 11CaO.7Al2O3.CaF2 and the confirmation of its crystal structure

Single crystals of 11CaO . 7Al(2)O(3) . CaF2(C(11)A(7) . CaF2) of 40-120 mu m in size were prepared by a flux evaporation method. The crystals were colorless trigonal tristetrahedrons with a refractive index of 1.601. By the method of single crystal X-ray diffraction it has been confirmed that the C(11)A(7) . CaF2 is cubic, with a = 11.981 Angstrom, space group , Z = 2 and D-X = 2.720 g cm(-3) The calcium atom is coordinated either to six oxygen atoms in an irregular [CaO6] coordination with 2.380 Angstrom, 2.401 Angstrom and 2.502 Angstrom for Ca-O distances or to six oxygen atoms and one fluorine atom in an asymmetric arrangement with 2.816 Angstrom for F-Ca distance. The aluminum atoms are coordinated to four oxygen atoms forming two different AlO4 tetrahedra: (1) the [Al(1)O(2)(4)], with symmetry (4) over bar and Al(1)-O(2) distance 1.745 Angstrom; and (2) the [Al(2)O-4] composed of one Al(2) atom, one O(1) atom and three O(2) atoms, with symmetry 3, Al(2)-O(1) distance = 1.740 Angstrom and Al(2)-O(2) distance = 1.757 Angstrom. Neighboring AlO4 tetrahedra are connected with each other by sharing oxygen atoms resulting in a three dimensional [AlO4] network-the basic framework of the crystal structure of C(11)A(7) . CaF2. (C) 1997 Elsevier Science Ltd

Survivin as a therapeutic target in Sonic hedgehog-driven medulloblastoma.

Medulloblastoma (MB) is a highly malignant brain tumor that occurs primarily in children. Although surgery, radiation and high-dose chemotherapy have led to increased survival, many MB patients still die from their disease, and patients who survive suffer severe long-term side effects as a consequence of treatment. Thus, more effective and less toxic therapies for MB are critically important. Development of such therapies depends in part on identification of genes that are necessary for growth and survival of tumor cells. Survivin is an inhibitor of apoptosis protein that regulates cell cycle progression and resistance to apoptosis, is frequently expressed in human MB and when expressed at high levels predicts poor clinical outcome. Therefore, we hypothesized that Survivin may have a critical role in growth and survival of MB cells and that targeting it may enhance MB therapy. Here we show that Survivin is overexpressed in tumors from patched (Ptch) mutant mice, a model of Sonic hedgehog (SHH)-driven MB. Genetic deletion of survivin in Ptch mutant tumor cells significantly inhibits proliferation and causes cell cycle arrest. Treatment with small-molecule antagonists of Survivin impairs proliferation and survival of both murine and human MB cells. Finally, Survivin antagonists impede growth of MB cells in vivo. These studies highlight the importance of Survivin in SHH-driven MB, and suggest that it may represent a novel therapeutic target in patients with this disease

The Slowdown in Global Air-Pollutant Emission Growth and Driving Factors

Fine-particulate-matter pollution (PM2.5) is linked to millions of deaths annually. Consumption in one region can cause production and PM2.5 emissions in another, but the socioeconomic drivers of transboundary PM2.5 emissions are not fully understood. Here, we quantify the driving factors of primary-particle and oxidized-precursor emissions from 2004 to 2011 at global and regional scales. The results indicate that the growth rate of global PM2.5 emissions slowed from 2004 to 2011, mainly due to improvements in energy intensities and production efficiency. Improvements in the emission intensity of coal represent the main factor offsetting SO2 and NOx emissions, whereas emission controls implemented for industrial processes have largely contributed to reducing primary PM2.5 emissions. The net emissions embodied in East Asia's exports to developed countries declined, while that to developing countries increased rapidly. The analysis creates opportunities to involve both producers and consumers in co-mitigation of various pollutants

A comparison of nitrogen utilization and urea metabolism between Tibetan and fine-wool sheep

Citation: Zhou, J. W., Mi, J. D., Titgemeyer, E. C., Guo, X. S., Ding, L. M., Wang, H. C., . . . Long, R. J. (2015). A comparison of nitrogen utilization and urea metabolism between Tibetan and fine-wool sheep. Journal of Animal Science, 93(6), 3006-3017. doi:10.2527/jas2014-8865To study metabolic adaptation to harsh foraging conditions, an experiment was conducted to characterize and quantify N utilization efficiency and urea metabolism in Tibetan and fine-wool sheep fed 4 levels of dietary N (11.0, 16.7, 23.1, and 29.2 g N/kg DM) in 2 concurrent 4 x 4 Latin square designs. Urea kinetics were determined using continuous intrajugular infusions of (NN)-N-15-N-15-urea. Urinary excretions of total N and urea N increased linearly (P = 0.37). Fecal N excretion increased with dietary N for Tibetan sheep but not for fine-wool sheep (linear dietary N x breed; P < 0.05). Nitrogen retention (both amount per day and percentage of N intake) increased with increasing dietary N concentration (P < 0.001), and the rates of increase were greater in fine-wool than in Tibetan sheep (linear dietary N x breed and cubic dietary N x breed; P < 0.05). In Tibetan sheep, N retention as a percentage of intake was greatest for diets containing 16.7 g N/kg DM, whereas it was maximal for fine-wool sheep when the diet contained 23.1 g N/kg DM. Urea N entry rate, urea N recycled to the gastrointestinal tract (GIT), and urea N returned to the ornithine cycle all increased with dietary N (P < 0.05), and all were greater in Tibetan than fine-wool sheep for the 11.0 g N/kg DM diet but were greater in fine-wool than Tibetan sheep for the diet with 29.2 g N/kg DM (linear dietary N x breed; P < 0.05). Urea N excreted in feces, both amount and fraction of GIT entry rate, was less in Tibetan than finewool sheep for the 11.0 and 16.7 g N/kg DM diets but similar for diets with 23.1 or 29.2 g N/kg DM (linear dietary N x breed; P < 0.01). For the lowest-protein diet, the fraction of urea N production recycled to the GIT was greater in the Tibetan than fine-wool sheep (88% vs. 82%), but for the diet with 29.2 g N/kg DM it was greater for fine-wool than Tibetan sheep (46% vs. 39%; linear dietary N x breed; P < 0.05). Plasma urea N increased more rapidly in response to increasing dietary N concentration for fine-wool sheep than for Tibetan sheep (linear dietary N x breed; P < 0.05). Urea tubular load and the amount and percentage of urea reabsorbed by the kidney were greater in Tibetan than fine-wool sheep (P < 0.05). These results suggest that Tibetan sheep have mechanisms that allow them to utilize N more efficiently than the fine-wool sheep when dietary N is inadequate

Dynamics of multipartite quantum correlations under decoherence

Quantum discord is an optimal resource for the quantification of classical and non-classical correlations as compared to other related measures. Geometric measure of quantum discord is another measure of quantum correlations. Recently, the geometric quantum discord for multipartite states has been introduced by Jianwei Xu [arxiv:quant/ph.1205.0330]. Motivated from the recent study [Ann. Phys. 327 (2012) 851] for the bipartite systems, I have investigated global quantum discord (QD) and geometric quantum discord (GQD) under the influence of external environments for different multipartite states. Werner-GHZ type three-qubit and six-qubit states are considered in inertial and non-inertial settings. The dynamics of QD and GQD is investigated under amplitude damping, phase damping, depolarizing and flipping channels. It is seen that the quantum discord vanishes for p>0.75 in case of three-qubit GHZ states and for p>0.5 for six qubit GHZ states. This implies that multipartite states are more fragile to decoherence for higher values of N. Surprisingly, a rapid sudden death of discord occurs in case of phase flip channel. However, for bit flip channel, no sudden death happens for the six-qubit states. On the other hand, depolarizing channel heavily influences the QD and GQD as compared to the amplitude damping channel. It means that the depolarizing channel has the most destructive influence on the discords for multipartite states. From the perspective of accelerated observers, it is seen that effect of environment on QD and GQD is much stronger than that of the acceleration of non-inertial frames. The degradation of QD and GQD happens due to Unruh effect. Furthermore, QD exhibits more robustness than GQD when the multipartite systems are exposed to environment.Comment: 15 pages, 4 figures, 4 table