3,504 research outputs found

    Solution Of Wheeler-De Witt Equation, Potential Well And Tunnel Effect

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    This paper uses the relation of the cosmic scale factor and scalar field to solve Wheeler-DeWitt equation, gives the tunnel effect of the cosmic scale factor a and quantum potential well of scalar field, and makes it fit with the physics of cosmic quantum birth. By solving Wheeler-DeWitt equation we achieve a general probability distribution of the cosmic birth, and give the analysis of cosmic quantum birth.Comment: 12 page

    Characterizing top gated bilayer graphene interaction with its environment by Raman spectroscopy

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    In this work we study the behavior of the optical phonon modes in bilayer graphene devices by applying top gate voltage, using Raman scattering. We observe the splitting of the Raman G band as we tune the Fermi level of the sample, which is explained in terms of mixing of the Raman (Eg) and infrared (Eu) phonon modes, due to different doping in the two layers. We theoretically analyze our data in terms of the bilayer graphene phonon self-energy which includes non-homogeneous charge carrier doping between the graphene layers. We show that the comparison between the experiment and theoretical model not only gives information about the total charge concentration in the bilayer graphene device, but also allows to separately quantify the amount of unintentional charge coming from the top and the bottom of the system, and therefore to characterize the interaction of bilayer graphene with its surrounding environment

    Doping Dependence of the Magnetic Resonance Peak in YBa_2 Cu_3 O_{6+x}

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    We report inelastic neutron scattering experiments on the doping dependence of the energy and spectral weight of the sharp magnetic resonance peak in YBa_2 Cu_3 O_{6+x}. These measurements also shed light on the relationship between the magnetic excitations in the normal and superconducting states.Comment: (mostly corrections to figures and minor change to caption in Fig.5) 5 figures. It will be published in the proceedings of M2S-HTSC-V. It needs the elsevier style file (not included) to convert to postscrip

    A probabilistic approach to Zhang's sandpile model

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    The current literature on sandpile models mainly deals with the abelian sandpile model (ASM) and its variants. We treat a less known - but equally interesting - model, namely Zhang's sandpile. This model differs in two aspects from the ASM. First, additions are not discrete, but random amounts with a uniform distribution on an interval [a,b][a,b]. Second, if a site topples - which happens if the amount at that site is larger than a threshold value EcE_c (which is a model parameter), then it divides its entire content in equal amounts among its neighbors. Zhang conjectured that in the infinite volume limit, this model tends to behave like the ASM in the sense that the stationary measure for the system in large volumes tends to be peaked narrowly around a finite set. This belief is supported by simulations, but so far not by analytical investigations. We study the stationary distribution of this model in one dimension, for several values of aa and bb. When there is only one site, exact computations are possible. Our main result concerns the limit as the number of sites tends to infinity, in the one-dimensional case. We find that the stationary distribution, in the case aEc/2a \geq E_c/2, indeed tends to that of the ASM (up to a scaling factor), in agreement with Zhang's conjecture. For the case a=0a=0, b=1b=1 we provide strong evidence that the stationary expectation tends to 1/2\sqrt{1/2}.Comment: 47 pages, 3 figure

    Effects of Fluctuating Temperatures on Isowean Pigs

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    This study quantifies responses of isowean pigs (10 to 12 days of age, PIC breed) to potential in-transit temperature fluctuations for 54 h, followed by a 14-day growth period under thermoneutrality. The 54-h temperature regimens included a constant air temperature of 26.7°C (as control) and three cyclic air temperatures of 26.7 ± 2.8°C, 26.7 ± 5.6°C and 26.7 ± 8.3°C, all using woodshavings bedding atop rigid board insulation. The pigs received an average dosage of 0.91 kg/pig water replacement supply during the 54-h treatment period, and ad-libitum feeding and watering during the growth period. Pigs in all three treatments and the control had similar growth performance, physiological, and energetic responses during both treatment and growth periods. At the end of the treatment period, the pigs had elevated concentrations of hematocrit, plasma protein, blood urea nitrogen, sodium and chloride, but declined concentration of glucose (P \u3c 0.05). Potassium and bicarbonate levels remained relatively constant (P \u3e 0.05). Concentrations of the blood constituents returned to normal during the growth period. The results suggest that the isowean pigs respond well to air temperature fluctuations of up to ±8.3°C around the thermoneutral condition of 26.7°C air temperature coupled with woodshavings bedding

    Transporting Isowean Pigs—Part II: Responses to Potential In-transit Thermal Conditions

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    The goal of this research was to explore the feasibility and protocols to transport isowean pigs long distance. This study was the second part of the effort that examined the thermal environment aspects of such a practice. Isowean pigs of PIC genetics (10 to 12 days old) were subjected to simulated 54-h in-transit temperature pattern of 80 ± 0, 5, 10 or 15°F. The pigs were provided with water supplement (average dosage of 2 lb/pig) during the treatment period and ad libitum feeding during a 14-d growth period. All pigs had similar weight loss (8.4 to 8.9% of their initial body weight) during the treatment period. The only difference in total weight gain during the growth period was between pigs previously exposed to 80 ± 15°F (8.33 lb) and those previously exposed to 80 ± 10°F (9.15 lb) (P0.05). All pigs showed similar physiological and energetic responses during both treatment and growth periods. The treatment period led to elevated concentrations of hematocrit, plasma protein, blood urea nitrogen, sodium and chloride, but declined glucose level (

    Paradoxical effects of the cannabinoid CB2 receptor agonist GW405833 on rat osteoarthritic knee joint pain

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    SummaryObjectiveThe present study examined whether local administration of the cannabinoid-2 (CB2) receptor agonist GW405833 could modulate joint nociception in control rat knee joints and in an animal model of osteoarthritis (OA).MethodOA was induced in male Wistar rats by intra-articular injection of sodium monoiodo-acetate with a recovery period of 14 days. Immunohistochemistry was used to evaluate the expression of CB2 and transient receptor potential vanilloid channel-1 (TRPV1) receptors in the dorsal root ganglion (DRG) and synovial membrane of sham- and sodium mono-iodoacetate (MIA)-treated animals. Electrophysiological recordings were made from knee joint primary afferents in response to rotation of the joint both before and following close intra-arterial injection of different doses of GW405833. The effect of intra-articular GW405833 on joint pain perception was determined by hindlimb incapacitance. An in vitro neuronal release assay was used to see if GW405833 caused release of an inflammatory neuropeptide (calcitonin gene-related peptide – CGRP).ResultsCB2 and TRPV1 receptors were co-localized in DRG neurons and synoviocytes in both sham- and MIA-treated animals. Local application of the GW405833 significantly reduced joint afferent firing rate by up to 31% in control knees. In OA knee joints, however, GW405833 had a pronounced sensitising effect on joint mechanoreceptors. Co-administration of GW405833 with the CB2 receptor antagonist AM630 or pre-administration of the TRPV1 ion channel antagonist SB366791 attenuated the sensitising effect of GW405833. In the pain studies, intra-articular injection of GW405833 into OA knees augmented hindlimb incapacitance, but had no effect on pain behaviour in saline-injected control joints. GW405833 evoked increased CGRP release via a TRPV1 channel-dependent mechanism.ConclusionThese data indicate that GW405833 reduces the mechanosensitivity of afferent nerve fibres in control joints but causes nociceptive responses in OA joints. The observed pro-nociceptive effect of GW405833 appears to involve TRPV1 receptors

    The X10 Flare on 2003 October 29: Triggered by Magnetic Reconnection between Counter-Helical Fluxes?

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    Vector magnetograms taken at Huairou Solar Observing Station (HSOS) and Mees Solar Observatory (MSO) reveal that the super active region (AR) NOAA 10486 was a complex region containing current helicity flux of opposite signs. The main positive sunspots were dominated by negative helicity fields, while positive helicity patches persisted both inside and around the main positive sunspots. Based on a comparison of two days of deduced current helicity density, pronounced changes were noticed which were associated with the occurrence of an X10 flare that peaked at 20:49 UT, 2003 October 29. The average current helicity density (negative) of the main sunspots decreased significantly by about 50. Accordingly, the helicity densities of counter-helical patches (positive) were also found to decay by the same proportion or more. In addition, two hard X-ray (HXR) `footpoints' were observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI} during the flare in the 50-100 keV energy range. The cores of these two HXR footpoints were adjacent to the positions of two patches with positive current helicity which disappeared after the flare. This strongly suggested that the X10 flare on 2003 Oct. 29 resulted from reconnection between magnetic flux tubes having opposite current helicity. Finally, the global decrease of current helicity in AR 10486 by ~50% can be understood as the helicity launched away by the halo coronal mass ejection (CME) associated with the X10 flare.Comment: Solar Physics, 2007, in pres

    A Tris β-Diketonate Europium(III) Complex Based OLED Fabricated by Thermal Evaporation Method Displaying Efficient Bright Red Emission

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    202209 bcwwNot applicableRGCOthersHis Majesty’s Trust Fund for Strategic Research; Brazilian funding agencies: CAPES, CNPq,FACEPE and FAPITEC/SE; Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials; Hong Kong Polytechnic University; Endowed Professorship in Energy from Ms Clarea Au; NSFC; outh Innovation Promotion Association of Chinese Academy of Sciences; Engineering and Physical Sciences Research Council (EPSRC)Published24 month
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