Current distribution of collective thermal depinning of Josephson vortices in naturally stacked Josephson junctions

We investigated the thermal-depinning current (I(c)) distribution of Josephson vortices (JVs) in naturally stacked Bi(2)Sr(2)CaCu(2)O(8+delta) intrinsic Jospehson junctions in tesla-range magnetic fields and at different field tilt angles from the in-plane position. The I(c) distribution in the thermal-activation regime contains accurate information on the bias and magnetic-field dependence of the Josephson-vortex pinning potential. In a few-tesla-range magnetic field, JVs in a row in a junction, strongly coupled with each other, are pinned or depinned like a single physical entity at a single pinning center. In the best-aligned in-plane magnetic field, the edge pinning is most relevant and is insensitive to the field strength. In the presence of pancake vortices (PVs) in a slightly tilted field, however, the PV pinning deepens the JV pinning potential linearly with the number of PVs.open1122sciescopu

Coefficient of standardized total tract digestibility of phosphorus in oilseed meals and distillers dried grains in growing-finishing pigs

This study was conducted to determine the coefficient of total tract standardized digestibility (CTTSD) of phosphorus (P) in oilseed meals and distillers dried grains (DDG) fed to growing-finishing pigs. Twelve barrows (initial bodyweight (BW) standard deviation, 52.25 +/- 2.57 kg) were allocated individually to metabolism cages. The experimental design was a 12 x 8 incomplete Latin square with 12 dietary treatments and eight replication periods. The diets were formulated individually with dehulled soybean meal produced in Korea (SBM-KD), soybean meal produced in India (SBM-I), soybean meal produced in Korea (SBM-K), corn high-protein distiller dried grains (HPDDGs), tapioca distillers dried grains (TDDG), canola meal (CAM), corn germ meal (CGM), copra meal (CM), palm kernel meal (PKM), sesame meal (SM), perilla meal (PM), and a P-free diet. Intake of P was highest in SM and PM. Excretion of P was reduced in y ascending order as HPDDG, TDDG and CGM; SBM-K; and SM and PM. The CTTAD of P was higher in CGM than SBM-K, TDDG, SM and PM. HPDDG and CGM showed greater CTTSD of P than SBM-K, CAM and PM. Digestible concentration of P on CTTSD (CTTSD-P) of P was greater in PM and CAM than the others except for SBM-KD. In summary, PM could be utilized as an alternative feedstuff to SBM, but its usage is regarded only as a source of P. In addition, the results of the current study would provide valuable information for formulating pig feed with precise P utilization in ingredients using mixed diet

UBR2 of the N-end rule pathway is required for chromosome stability via histone ubiquitylation in spermatocytes and somatic cells

The N-end rule pathway is a proteolytic system in which its recognition components (N-recognins) recognize destabilizing N-terminal residues of short-lived proteins as an essential element of specific degrons, called N-degrons. The RING E3 ligases UBR2 and UBR1 are major N-recognins that share size (200 kDa), conserved domains and substrate specificities to N-degrons. Despite the known function of the N-end rule pathway in degradation of cytosolic proteins, the major phenotype of UBR2-deficient male mice is infertility caused by arrest of spermatocytes at meiotic prophase I. UBR2-deficient spermatocytes are impaired in transcriptional silencing of sex chromosome-linked genes and ubiquitylation of histone H2A. In this study we show that the recruitment of UBR2 to meiotic chromosomes spatiotemporally correlates to the induction of chromatin-associated ubiquitylation, which is significantly impaired in UBR2-deficient spermatocytes. UBR2 functions as a scaffold E3 that promotes HR6B/UbcH2-dependent ubiquitylation of H2A and H2B but not H3 and H4, through a mechanism distinct from typical polyubiquitylation. The E3 activity of UBR2 in histone ubiquitylation is allosterically activated by dipeptides bearing destabilizing N-terminal residues. Insufficient monoubiquitylation and polyubiquitylation on UBR2-deficient meiotic chromosomes correlate to defects in double strand break (DSB) repair and other meiotic processes, resulting in pachytene arrest at stage IV and apoptosis. Some of these functions of UBR2 are observed in somatic cells, in which UBR2 is a chromatin-binding protein involved in chromatin-associated ubiquitylation upon DNA damage. UBR2-deficient somatic cells show an array of chromosomal abnormalities, including hyperproliferation, chromosome instability, and hypersensitivity to DNA damage-inducing reagents. UBR2-deficient mice enriched in C57 background die upon birth with defects in lung expansion and neural development. Thus, UBR2, known as the recognition component of a major cellular proteolytic system, is associated with chromatin and controls chromatin dynamics and gene expression in both germ cells and somatic cells. © 2012 Kwon et al

Evolution of superconductivity in K2-xFe4+ySe5: Spectroscopic studies of X-ray absorption and emission.

This study investigates the evolution of superconductivity in K2-xFe4+ySe5 using temperature-dependent X-ray absorption and resonant inelastic X-ray scattering techniques. Magnetization measurements show that polycrystalline superconducting (SC) K1.9Fe4.2Se5 has a critical temperature (T c) of ∼31 K with a varying superconducting volume fraction, which strongly depends on its synthesis temperature. An increase in Fe-structural/vacancy disorder in SC samples with more Fe atoms occupying vacant 4d sites is found to be closely related to the decrease in the spin magnetic moment of Fe. Moreover, the nearest-neighbor Fe-Se bond length in SC samples exceeds that in the non-SC (NS) sample, K2Fe4Se5, which indicates a weaker hybridization between the Fe 3d and Se 4p states in SC samples. These results clearly demonstrate the correlations among the local electronic and atomic structures and the magnetic properties of K2-xFe4+ySe5 superconductors, providing deeper insight into the electron pairing mechanisms of superconductivity

Giant Superfluorescent Bursts from a Semiconductor Magnetoplasma

Currently, considerable resurgent interest exists in the concept of superradiance (SR), i.e., accelerated relaxation of excited dipoles due to cooperative spontaneous emission, first proposed by Dicke in 1954. Recent authors have discussed SR in diverse contexts, including cavity quantum electrodynamics, quantum phase transitions, and plasmonics. At the heart of these various experiments lies the coherent coupling of constituent particles to each other via their radiation field that cooperatively governs the dynamics of the whole system. In the most exciting form of SR, called superfluorescence (SF), macroscopic coherence spontaneously builds up out of an initially incoherent ensemble of excited dipoles and then decays abruptly. Here, we demonstrate the emergence of this photon-mediated, cooperative, many-body state in a very unlikely system: an ultradense electron-hole plasma in a semiconductor. We observe intense, delayed pulses, or bursts, of coherent radiation from highly photo-excited semiconductor quantum wells with a concomitant sudden decrease in population from total inversion to zero. Unlike previously reported SF in atomic and molecular systems that occur on nanosecond time scales, these intense SF bursts have picosecond pulse-widths and are delayed in time by tens of picoseconds with respect to the excitation pulse. They appear only at sufficiently high excitation powers and magnetic fields and sufficiently low temperatures - where various interactions causing decoherence are suppressed. We present theoretical simulations based on the relaxation and recombination dynamics of ultrahigh-density electron-hole pairs in a quantizing magnetic field, which successfully capture the salient features of the experimental observations.Comment: 21 pages, 4 figure

Software-defined networking for ubiquitous healthcare service delivery

The growth of the mobile, portable devices and the server-to-server communication through cloud computing increase the network traffic. The dependence of the ubiquitous healthcare service delivery on the network connectivity creates failures that may interrupt or delay the treatment plan with adverse effects in patients’ quality of life even leading to mortality. In the present work, we propose the incorporation of Software Defined Networking (SDN) features in the healthcare domain in order to provide the appropriate bandwidth and guarantee the accurate real time medical data transmission independently of the connectivity of the ISP provider. The SDN controller monitors the network traffic and specifies how traffic should be routed providing load balancing, lower delays and better performance. Finally, the proposed healthcare architecture addresses the SDN scalability challenge by incorporating the logically centralized control plane using multiple distributed controllers. A 2-tier hierarchical overlay is formed among SDN controllers following the principles of peer-to-peer networking

Reduction in CO2 uptake rates of red tide dinoflagellates due to mixotrophy

We investigated a possible reduction in CO2 uptake rate by phototrophic red tide dinoflagellates arising from mixotrophy. We measured the daily ingestion rates of Prorocentrum minimum by Prorocentrum micans over 5 days in 10 L experimentalbottles, and the uptake rates of total dissolved inorganic carbon (CT) by a mixture of P. micans and P. minimum(mixotrophic growth), and for the predator P. micans (phototrophic growth; control) and prey P. minimum (phototrophicgrowth; control) alone. To account for the effect of pH on the phototrophic growth rates of P. micans and P. minimum,measurements of CT and pH in the predator and prey control bottles were continued until the pH reached the same level(pH 9.5) as that in the experimental bottles on the final day of incubation. The measured total CT uptake rate by the mixtureof P. micans and P. minimum changed from 123 to 161 μmol CT kg-1 d-1 over the course of the experiment, and waslower than the CT uptake rates shown by P. micans and P. minimum in the predator and prey control bottles, respectively,which changed from 132 to 176 μmol CT kg-1 d-1 over the course of the experiment. The reduction in total CT uptake ratearising from the mixotrophy of P. micans was 7-31% of the daily CT uptake rate seen during photosynthesis. The resultssuggest that red tide dinoflagellates take up less CT during mixotrophy.1131Ysciescopuskc

Momentum-resolved resonant inelastic soft X-ray scattering (qRIXS) endstation at the ALS

A momentum resolved resonant inelastic X-ray scattering (qRIXS) experimental station with continuously rotatable spectrometers and parallel detection is designed to operate at different beamlines at synchrotron and free electron laser (FEL) facilities. This endstation, currently located at the Advanced Light Source (ALS), has five emission ports on the experimental chamber for mounting the high-throughput modular soft X-ray spectrometers (MXS) [24]. Coupled to the rotation from the supporting hexapod, the scattered X-rays from 27.5° (forward scattering) to 152.5° (backward scattering) relative to the incident photon beam can be recorded, enabling the momentum-resolved RIXS spectroscopy. The components of this endstation are described in details, and the preliminary RIXS measurements on highly oriented pyrolytic graphite (HOPG) reveal the low energy vibronic excitations from the strong electron-phonon coupling at C K edge around σ* band. The grating upgrade option to enhance the performance at low photon energies is presented and the potential of this spectroscopy is discussed in summary

A possible method for non-Hermitian and non-PTPT-symmetric Hamiltonian systems

A possible method to investigate non-Hermitian Hamiltonians is suggested through finding a Hermitian operator $\eta_+$ and defining the annihilation and creation operators to be $\eta_+$-pseudo-Hermitian adjoint to each other. The operator $\eta_+$ represents the $\eta_+$-pseudo-Hermiticity of Hamiltonians. As an example, a non-Hermitian and non-$PT$-symmetric Hamiltonian with imaginary linear coordinate and linear momentum terms is constructed and analyzed in detail. The operator $\eta_+$ is found, based on which, a real spectrum and a positive-definite inner product, together with the probability explanation of wave functions, the orthogonality of eigenstates, and the unitarity of time evolution, are obtained for the non-Hermitian and non-$PT$-symmetric Hamiltonian. Moreover, this Hamiltonian turns out to be coupled when it is extended to the canonical noncommutative space with noncommutative spatial coordinate operators and noncommutative momentum operators as well. Our method is applicable to the coupled Hamiltonian. Then the first and second order noncommutative corrections of energy levels are calculated, and in particular the reality of energy spectra, the positive-definiteness of inner products, and the related properties (the probability explanation of wave functions, the orthogonality of eigenstates, and the unitarity of time evolution) are found not to be altered by the noncommutativity.Comment: 15 pages, no figures; v2: clarifications added; v3: 16 pages, 1 figure, clarifications made clearer; v4: 19 pages, the main context is completely rewritten; v5: 25 pages, title slightly changed, clarifications added, the final version to appear in PLOS ON

Toward a Molecular Understanding of Plant Hormone Actions

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