10,107 research outputs found

    Primordial follicular assembly in humans : revisited

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    Detection of transgenic and endogenous plant DNA in blood and organs of Nile tilapia, Oreochromis niloticus fed a diet formulated with genetically modified soybean meal

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    Anxiety regarding the fate of ingested transgenic DNA in farmed fish fed genetically modified (GM) soybean meal (SBM) has been raised with regard to human consumption. The objective of this study was to detect possibility of gene transfer of transgenic and endogenous DNA fragments in Nile tilapia (Oreochromis niloticus) blood and organs after consumption of a GM SBM diet. Nile tilapias with an average weight of 75.0 g were fed diets containing 48% GM or non-GM SBM for 21 days. During this period, a GM SBM diet was fed to fish for 12 days, and then switched to feed with non-GM SBM for 9 days for determining the residual span of the transferred cauliflower mosaic virus (CaMV) 35S promoter fragment. Blood, spleen, liver, intestine, kidney, and muscle tissues were taken (n = 10) every three days during the feeding period. Total DNA was extracted from the samples and analyzed by polymerase chain reaction (PCR) for determining the presence of a 108-bp fragment of the CaMV 35S promoter and a 144-bp fragment of the soybean chloroplast-specific DNA. Low-copy chloroplast-specific DNA fragment was detected in all organ and tissue samples and the majority of intestinal samples of fish fed GM SBM diet. Similarly, a low number and faint signals of the CaMV 35S promoter fragments were detected in all organ samples except muscle of fish fed the GM SBM diet, while none were detected 3 days after changing to a non-GM SBM diet. A very low frequency of transmittance to muscle and organs of fish was confirmed. It is recognized that the low copy number of transgenic DNA in the GM SBM diet is a challenge to their detection in tissues. These results suggested that transgenic DNA would be processed in the gastrointestinal tract in a similar manner with conventional plant DNA

    Magnetic ground state of pyrochlore oxides close to metal-insulator boundary probed by muon spin rotation

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    Magnetism of ruthernium pyrochlore oxides A2Ru2O7 (A = Hg, Cd, Ca), whose electronic properties within a localized ion picture are characterized by non-degenerate t2g orbitals (Ru5+, 4d3) and thereby subject to geometrical frustration, has been investigated by muon spin rotation/relaxation (muSR) technique. The A cation (mostly divalent) was varied to examine the effect of covalency (Hg > Cd > Ca) on their electronic property. In a sample with A = Hg that exhibits a clear metal-insulator (MI) transition below >> 100 K (which is associated with a weak structural transition), a nearly commensurate magnetic order is observed to develop in accordance with the MI transition. Meanwhile, in the case of A = Cd where the MI transition is suppressed to the level of small anomaly in the resistivity, the local field distribution probed by muon indicates emergence of a certain magnetic inhomogeneity below {\guillemotright} 30 K. Moreover, in Ca2Ru2O7 that remains metallic, we find a highly inhomogeneous local magnetism below >>25 K that comes from randomly oriented Ru moments and thus described as a "frozen spin liquid" state. The systematic trend of increasing randomness and itinerant character with decreasing covalency suggests close relationship between these two characters. As a reference for the effect of orbital degeneracy and associated Jahn-Teller instability, we examine a tetravalent ruthernium pyrochlore, Tl2Ru2O7 (Ru4+, 4d4), where the result of muSR indicates a non-magnetic ground state that is consistent with the formation of the Haldane chains suggested by neutron diffraction experiment.Comment: 12 pages, 13 figure

    An Efficient Algorithm for Enumerating Chordless Cycles and Chordless Paths

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    A chordless cycle (induced cycle) CC of a graph is a cycle without any chord, meaning that there is no edge outside the cycle connecting two vertices of the cycle. A chordless path is defined similarly. In this paper, we consider the problems of enumerating chordless cycles/paths of a given graph G=(V,E),G=(V,E), and propose algorithms taking O(E)O(|E|) time for each chordless cycle/path. In the existing studies, the problems had not been deeply studied in the theoretical computer science area, and no output polynomial time algorithm has been proposed. Our experiments showed that the computation time of our algorithms is constant per chordless cycle/path for non-dense random graphs and real-world graphs. They also show that the number of chordless cycles is much smaller than the number of cycles. We applied the algorithm to prediction of NMR (Nuclear Magnetic Resonance) spectra, and increased the accuracy of the prediction

    Slow-roll Inflation with the Gauss-Bonnet and Chern-Simons Corrections

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    We study slow-roll inflation with the Gauss-Bonnet and Chern-Simons corrections. We obtain general formulas for the observables: spectral indices, tensor-to-scalar ratio and circular polarization of gravitational waves. The Gauss-Bonnet term violates the consistency relation r = -8n_T. Particularly, blue spectrum n_T > 0 and scale invariant spectrum |8n_T|/r << 1 of tensor modes are possible. These cases require the Gauss-Bonnet coupling function of \xi _{,\phi } \sim 10^8/M_{Pl}. We use examples to show new-inflation-type potential with 10M_{Pl} symmetry breaking scale and potential with flat region in \phi \gtrsim 10M_{Pl} lead to observationally consistent blue and scale invariant spectra, respectively. Hence, these interesting cases can actually be realized. The Chern-Simons term produce circularly polarized tensor modes. We show an observation of these signals supports existence of the Chern-Simons coupling function of \omega _{,\phi } \sim 10^8/M_{Pl}. Thus, with future observations, we can fix or constrain the value of these coupling functions, at the CMB scale.Comment: 21 pages, 5 figure

    Design of Sliding Mode Techniques for a CMG-based Testbed Attitude Control System

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    Precise pointing accuracy and rapid maneuvering are two key features for attitude control missions of small spacecraft. Control moment gyroscopes (CMGs) are applied as ideal actuator for large torque output capability but are usually limited due to the problem of inherent mechanical singularity. This paper proposes a robust attitude control methodology, based on Sliding Mode Control (SMC) techniques, in presence of CMG practical restrictions and disturbances. Two second-order SMC techniques are designed, to guarantee accuracy and limited convergence time. Moreover, attitude control torques are generated by means of four single gimbal CMGs in pyramidal configuration, considering the design of an experimental testbed. The effectiveness of the proposed methodologies are shown in simulations, for different mission scenarios, including singularity points

    A note on string solutions in AdS_3

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    We systematically search for classical open string solutions in AdS_3 within the general class expressed by elliptic functions (i.e., the genus-one finite-gap solutions). By explicitly solving the reality and Virasoro conditions, we give a classification of the allowed solutions. When the elliptic modulus degenerates, we find a class of solutions with six null boundaries, among which two pairs are collinear. By adding the S^1 sector, we also find four-cusp solutions with null boundaries expressed by the elliptic functions.Comment: 17 pages, 1 figure; (v2) added 1 figure and discussion on solutions with 6 null boundaries; (v3) corrected equation numbers; (v4) added comment

    Quantum network coding for quantum repeaters

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    This paper considers quantum network coding, which is a recent technique that enables quantum information to be sent on complex networks at higher rates than by using straightforward routing strategies. Kobayashi et al. have recently showed the potential of this technique by demonstrating how any classical network coding protocol gives rise to a quantum network coding protocol. They nevertheless primarily focused on an abstract model, in which quantum resource such as quantum registers can be freely introduced at each node. In this work, we present a protocol for quantum network coding under weaker (and more practical) assumptions: our new protocol works even for quantum networks where adjacent nodes initially share one EPR-pair but cannot add any quantum registers or send any quantum information. A typically example of networks satisfying this assumption is {\emph{quantum repeater networks}}, which are promising candidates for the implementation of large scale quantum networks. Our results thus show, for the first time, that quantum network coding techniques can increase the transmission rate in such quantum networks as well.Comment: 9 pages, 11figure
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