4,928 research outputs found

    Possibly New Charmed Baryon States from Bˉ0ppˉD0\bar B^0\to p\bar p D^{0} Decay

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    We examine the invariant mass spectrum of D0pD^{0}p in Bˉ0ppˉD0\bar B^0\to p\bar p D^{0} decay measured by BABAR and find that through the 2-step processes of Bˉ0Bc+(D0p)pˉ\bar B^0\to {\bf B_c^+}(\to D^{0} p)\bar p, where Bc{\bf B_c} denotes a charmed baryon state, some of the peaks can be identified with the established Σc(2800)+\Sigma_c(2800)^+, Λc(2880)+\Lambda_c(2880)^+ and Λc(2940)+\Lambda_c(2940)^+. Moreover, in order to account for the measured spectrum, it is necessary to introduce a new charmed baryon resonance with (m,Γ)=(3212±20,167±34)(m,\,\Gamma)=(3212\pm 20,\,167\pm 34) MeV.Comment: 8 pages, 1 figure, title changed and discussions updated, version accepted for publication in Phys. Rev.

    Activation of the maternal immune system induces endocrine changes in the placenta via IL-6

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    Activation of the maternal immune system in rodent models sets in motion a cascade of molecular pathways that ultimately result in autism- and schizophrenia-related behaviors in offspring. The finding that interleukin-6 (IL-6) is a crucial mediator of these effects led us to examine the mechanism by which this cytokine influences fetal development in vivo. Here we focus on the placenta as the site of direct interaction between mother and fetus and as a principal modulator of fetal development. We find that maternal immune activation (MIA) with a viral mimic, synthetic double-stranded RNA (poly(I:C)), increases IL-6 mRNA as well as maternally-derived IL-6 protein in the placenta. Placentas from MIA mothers exhibit increases in CD69+ decidual macrophages, granulocytes and uterine NK cells, indicating elevated early immune activation. Maternally-derived IL-6 mediates activation of the JAK/STAT3 pathway specifically in the spongiotrophoblast layer of the placenta, which results in expression of acute phase genes. Importantly, this parallels an IL-6-dependent disruption of the growth hormone-insulin-like growth factor (GH-IGF) axis that is characterized by decreased GH, IGFI and IGFBP3 levels. In addition, we observe an IL-6-dependent induction in pro-lactin-like protein-K (PLP-K) expression as well as MIA-related alterations in other placental endocrine factors. Together, these IL-6-mediated effects of MIA on the placenta represent an indirect mechanism by which MIA can alter fetal development

    Concurrent Design Strategy in Modeling and Structure of Electric Scooter for Young Disabilities

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    Disabled people often use the electric scooter as a means of transport. However, the electric scooter designed for disabilities is too bulky and not light in shape. It is not only awkward on the road but brings inconvenience to young people with disabilities. In the first phase of the study, first the electric scooter with a higher market share as a design reference was collected; then we use the image scale analysis to determine the market position of the electric scooter. Combine each major component and derive detail design of the product through Morphological chart method and Finite Structure Method (FSM). This study uses this method to complete the development of product modeling and analyze the configuration of the product as the main function in the structural and main function in space. Let function and appearance have the efficient combination. Then use Analytic Hierarchy Process (AHP) to obtain objective decision results. The use of Concurrent Design Strategy can effectively shorten the development process and increase the chance of product success.     Keywords: concurrent design, electric scooter, morphological chart method, finite structure method, analytical hierarchy proces

    Equivalent SU(3)fSU(3)_f approaches for two-body anti-triplet charmed baryon decays

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    For the two-body anti-triplet charmed baryon decays, there exist two theoretical analyses based on the SU(3)SU(3) flavor (SU(3)fSU(3)_f) symmetry. One is the irreducible SU(3)fSU(3)_f approach (IRA), which depends on the irreducible SU(3)fSU(3)_f representation of the effective Hamiltonian. The other is the topological-diagram approach (TDA), where the decays are drawn to consist of WW-boson emission and WW-boson exchange topologies. We demonstrate that IRA and TDA can be equivalent, such that the IRA parameters can be seen to mix with the TDA topologies. The current observations of Ξc0Ξπ+,ΞK+,Λ0Kˉ0\Xi_c^0\to \Xi^-\pi^+,\Xi^- K^+,\Lambda^0\bar K^0 might cause theoretical difficulties. With the SU(3)fSU(3)_f symmetry breaking, we explain B(Ξc0Ξπ+,ΞK+){\cal B}(\Xi_c^0\to\Xi^-\pi^+,\Xi^-K^+). It is found that a specific WW-boson exchange topology denoted by EME_M only appears in Ξc0BM\Xi_c^0\to{\bf B}M, by which we explain B(Ξc0Λ0Kˉ0){\cal B}(\Xi_c^0\to\Lambda^0\bar K^0). In addition, we predict B(Ξc0Σ0Kˉ0,Σ+K)=(5.83.5+4.7,5.43.4+4.9)×103{\cal B}(\Xi_c^0\to\Sigma^0\bar K^0,\Sigma^+ K^-)= (5.8^{+4.7}_{-3.5},5.4^{+4.9}_{-3.4})\times 10^{-3} for future measurements to test if EME_M can be a significant contribution.Comment: 13 pages, 7 tables, 1 figure, introduction rephrased, reference added, typos correcte

    Pictorial SU(3)fSU(3)_f approach for two-body Ωc\Omega_c weak decays

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    We explore two-body non-leptonic weak decays of Ωc0\Omega_c^0 into final states B()M{\bf B}^{(*)}M and B()V{\bf B}^{(*)}V, where B(){\bf B}^{(*)} denotes an octet (a decuplet) baryon, and M(V)M(V) represents a pseudoscalar (vector) meson. Based on the SU(3)SU(3) flavor [SU(3)f][SU(3)_f] symmetry, we depict and parameterize the WW-emission and WW-exchange processes using the topological diagram approach, establishing strict SU(3)fSU(3)_f relations for possible decay channels. We identify dominant topological parameters, determined by available data, allowing us to explain the experimental ratios B(Ωc0Ξ0Kˉ0)/B(Ωc0Ωρ+)=0.28±0.11{\cal B}(\Omega_c^0\to\Xi^{*0}\bar K^{*0})/{\cal B}(\Omega_c^0\to\Omega^-\rho^+)=0.28\pm 0.11, B(Ωc0Ξπ+)/B(Ωc0Ξ0Kˉ0)=0.10±0.02{\cal B}(\Omega_c^0\to\Xi^-\pi^+)/{\cal B}(\Omega_c^0\to\Xi^{0}\bar K^{0})=0.10\pm 0.02, and B(Ωc0ΩK+)/B(Ωc0Ωπ+)=0.06±0.01{\cal B}(\Omega_c^0 \to \Omega^- K^+)/{\cal B}(\Omega_c^0 \to \Omega^- \pi^+)=0.06\pm 0.01. We also calculate the branching fractions of the Cabibbo-allowed decays, such as B(Ωc0Ξ0Kˉ0)=(9.8±1.3)×104{\cal B}(\Omega_c^0 \to \Xi^{* 0} \bar{K}^{0})=(9.8\pm1.3)\times 10^{-4}. In particular, we establish approximate isospin relations: B(Ωc0Ξ()π+)2B(Ωc0Ξ()0π0){\cal B}(\Omega_c^0 \to \Xi^{(*)-} \pi^+)\simeq 2{\cal B}(\Omega_c^0 \to \Xi^{(*)0} \pi^0) and B(Ωc0Ξ()ρ+)2B(Ωc0Ξ()0ρ0){\cal B}(\Omega_c^0 \to \Xi^{(*)-} \rho^+)\simeq 2{\cal B}(\Omega_c^0 \to \Xi^{(*)0} \rho^0), where B(Ωc0Ξ0π0)=(2.3±0.2)×104{\cal B}(\Omega_c^0 \to \Xi^0 \pi^0)=(2.3\pm0.2)\times 10^{-4} is accessible to the Belle and LHCb experiments.Comment: 16 pages, 3 tables, 2 figure

    How Much Does Money Matter in a Direct Democracy?

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    The fine-structure splitting of quantum confined InxGa1-x Nexcitons is investigated using polarization-sensitive photoluminescence spectroscopy. The majority of the studied emission lines exhibits mutually orthogonal fine-structure components split by 100-340 mu eV, as measured from the cleaved edge of the sample. The exciton and the biexciton reveal identical magnitudes but reversed sign of the energy splitting.Original Publication:Supaluck Amloy, Y T Chen, K F Karlsson, K H Chen, H C Hsu, C L Hsiao, L C Chen and Per-Olof Holtz, Polarization-resolved fine-structure splitting of zero-dimensional InxGa1-xN excitons, 2011, PHYSICAL REVIEW B, (83), 20, 201307.http://dx.doi.org/10.1103/PhysRevB.83.201307Copyright: American Physical Societyhttp://www.aps.org

    Near-IR studies of recurrent nova V745 Scorpii during its 2014 outburst

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    The recurrent nova (RN) V745 Scorpii underwent its third known outburst on 2014 February 6. Infrared monitoring of the eruption on an almost daily basis, starting from 1.3d after discovery, shows the emergence of a powerful blast wave generated by the high velocity nova ejecta exceeding 4000 kms1^{-1} plowing into its surrounding environment. The temperature of the shocked gas is raised to a high value exceeding 108^{8}K immediately after outburst commencement. The energetics of the outburst clearly surpass those of similar symbiotic systems like RS Oph and V407 Cyg which have giant secondaries. The shock does not show a free-expansion stage but rather shows a decelerative Sedov-Taylor phase from the beginning. Such strong shockfronts are known to be sites for γ\gamma ray generation. V745 Sco is the latest nova, apart from five other known novae, to show γ\gamma ray emission. It may be an important testbed to resolve the crucial question whether all novae are generically γ\gamma ray emitters by virtue of having a circumbinary reservoir of material that is shocked by the ejecta rather than γ\gamma ray generation being restricted to only symbiotic systems with a shocked red giant (RG) wind. The lack of a free-expansion stage favors V745 Sco to have a density enhancement around the white dwarf (WD), above that contributed by a RG wind. Our analysis also suggests that the WD in V745 Sco is very massive and a potential progenitor for a future SN Ia explosion.Comment: To appear in ApJ (Letters
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