856 research outputs found

    New records of <i>Scolelepis</i> (Polychaeta : Spionidae) from the sandy beaches of Madagascar, with the description of a new species

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    Three species of the genus Scolelepis (Polychaeta, Spionidae) are reported from intertidal beaches in Madagascar. A new species, Scolelepis (Scolelepis) vazaha n.sp., is described from Cap Eat (type locality) and Fort Dauphin. This species is unique among spionids in possessing at least one large, curved hook in each notopodium of setiger 4. Males may additionally have similar hooks on setiger 5 or on setigers 5 and 6. On median setigers males also possess peculiar notopodial swellings, some of which contain a geniculate, penicillate seta of a type previously unknown for the family. S. (S.) williami (de Silva, 1961), formerly known only from the original description of two specimens from Sri Lanka, was found on five beaches along the southeast coast of Madagascar. This poorly known species is redescribed and compared to the closely related S. (S.) laciniata Eibye-Jacobsen, 1997, described from the west coast of Thailand. S. (S.) lefebvrei (Gravier, 1905), previously reported from the west coast of Madagascar, was also found on six sandy beaches along the northeast and southeast coasts. Earlier descriptions are supplemented by information on variation in numerical characters. Scanning electron photographs and details on palp morphology are provided for all three species

    Effect of Supersymmetric phases on the Direct CP Asymmetry of B -> X_d \gamma

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    We investigate the effect of supersymmetric CP violating phases on the inclusive decay B\to X_d\gamma. Although such a decay contains a large background from B\to X_s\gamma, if isolated it may exhibit sizeable CP violation, both in the Standard Model (SM) and in the context of models beyond the SM. With unconstrained supersymmetric CP violating phases we show that the direct CP asymmetry (A_CP) lies in the region -40% \le A_CP \le 40%, where a positive asymmetry would constitute a clear signal of physics beyond the SM. Even if a direct measurement of B\to X_d\gamma proves too dif ficult experimentally, its asymmetry contributes non-negligibly to the measurements of A_CP for B\to X_s\gamma, and thus should be included in future analyses. We show t hat there may be both constructive and destructive interference between A^d\gamma_CP and A^s\gamma_CP.Comment: 12 pages, 6 figures. Full Res. figures (and PostScript of paper) available at http://www-th.kek.jp/home/stefan/b2dgamma

    Nanomaterials for Advancing the Health Immunosensor

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    Nanotechnology has exerted a significant impact in the development of biosensors allowing more sensible analytical methods. In health applications, the main challenge of the immunoassay is to reach the suitable limit of detection, recognizing different analytes in complex samples like whole blood, serum, urine, and other biological fluids. Different nanomaterials, including metallic, silica and magnetic nanoparticles, quantum dots, carbon nanotubes, and graphene, have been applied, mainly to improve charge electron transfer, catalytic activity, amount of immobilized biomolecules, low-background current, signal-to-noise ratio that consequently increase the sensitivity of immunosensors. Given the great impact of nanotechnology, this chapter intends to discuss new aspects of nanomaterials relating to immunosensor advancement

    Stellar Inversion Techniques

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    Stellar seismic inversions have proved to be a powerful technique for probing the internal structure of stars, and paving the way for a better understanding of the underlying physics by revealing some of the shortcomings in current stellar models. In this lecture, we provide an introduction to this topic by explaining kernel-based inversion techniques. Specifically, we explain how various kernels are obtained from the pulsation equations, and describe inversion techniques such as the Regularised Least-Squares (RLS) and Optimally Localised Averages (OLA) methods.Comment: 20 pages, 8 figures. Lecture presented at the IVth Azores International Advanced School in Space Sciences on "Asteroseismology and Exoplanets: Listening to the Stars and Searching for New Worlds" (arXiv:1709.00645), which took place in Horta, Azores Islands, Portugal in July 201

    Rare Decays of \Lambda_b->\Lambda + \gamma and \Lambda_b ->\Lambda + l^{+} l^{-} in the Light-cone Sum Rules

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    Within the Standard Model, we investigate the weak decays of ΛbΛ+γ\Lambda_b \to \Lambda + \gamma and ΛbΛ+l+l\Lambda_b \to \Lambda + l^{+} l^{-} with the light-cone sum rules approach. The higher twist distribution amplitudes of Λ\Lambda baryon to the leading conformal spin are included in the sum rules for transition form factors. Our results indicate that the higher twist distribution amplitudes almost have no influences on the transition form factors retaining the heavy quark spin symmetry, while such corrections can result in significant impacts on the form factors breaking the heavy quark spin symmetry. Two phenomenological models (COZ and FZOZ) for the wave function of Λ\Lambda baryon are also employed in the sum rules for a comparison, which can give rise to the form factors approximately 5 times larger than that in terms of conformal expansion. Utilizing the form factors calculated in LCSR, we then perform a careful study on the decay rate, polarization asymmetry and forward-backward asymmetry, with respect to the decays of ΛbΛγ\Lambda_b \to \Lambda \gamma, Λl+l\Lambda l^{+}l^{-}.Comment: 38 pages, 15 figures, some typos are corrected and more references are adde

    Direct CP Asymmetry of B -> X_d,s \gamma in a model with Vector quarks

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    We investigate the effect of vector quarks on the inclusive decays B -> X_d,s \gamma. We show that the branching ratio of B -> X_d \gamma can differ sizably from the SM and MSSM predictions, being enhanced to present experimental observability or suppressed such that present runs of the B factories would not observe it. Current measurements of the direct CP asymmetry (A_CP) for B -> X_s \gamma are sensitive to the contribution from B -> X_d \gamma. For a sufficiently enhanced BR(B -> X_d \gamma) we show that the dominant contribution to the combined asymmetry may be from B -> X_d \gamma. Thus any large value for A_CP should not immediately be attributed to B -> X_s \gamma, which stresses the importance of good K/pi separation.Comment: 12 pages, 6 figures. v2: Minor changes, 3 references added, to be publ. in PL

    Removing Discrete Ambiguities in CP Asymmetry Measurements

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    We discuss methods to resolve the ambiguities in CP violating phase angles ϕ\phi that are left when a measurement of sin2ϕ\sin 2 \phi is made. We show what knowledge of hadronic quantities will be needed to fully resolve all such ambiguities.Comment: 23 pages, revtex, no figure

    Modeling the Subsurface Structure of Sunspots

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    While sunspots are easily observed at the solar surface, determining their subsurface structure is not trivial. There are two main hypotheses for the subsurface structure of sunspots: the monolithic model and the cluster model. Local helioseismology is the only means by which we can investigate subphotospheric structure. However, as current linear inversion techniques do not yet allow helioseismology to probe the internal structure with sufficient confidence to distinguish between the monolith and cluster models, the development of physically realistic sunspot models are a priority for helioseismologists. This is because they are not only important indicators of the variety of physical effects that may influence helioseismic inferences in active regions, but they also enable detailed assessments of the validity of helioseismic interpretations through numerical forward modeling. In this paper, we provide a critical review of the existing sunspot models and an overview of numerical methods employed to model wave propagation through model sunspots. We then carry out an helioseismic analysis of the sunspot in Active Region 9787 and address the serious inconsistencies uncovered by \citeauthor{gizonetal2009}~(\citeyear{gizonetal2009,gizonetal2009a}). We find that this sunspot is most probably associated with a shallow, positive wave-speed perturbation (unlike the traditional two-layer model) and that travel-time measurements are consistent with a horizontal outflow in the surrounding moat.Comment: 73 pages, 19 figures, accepted by Solar Physic
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