437 research outputs found

    Trophic modes of large Antarctic Foraminifera: roles of carnivory, omnivory, and detritivory

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    Astrammina rara, Crithionina delacai, and Notodendrodes hyalinosphaira are 3 of the largest and most abundant members of the foraminiferal assemblage at a shallow-water (28 to 32 m) site in Explorers Cove, Antarctica. This study summarizes observations from 2 decades of research, during which we employed laboratory-based feeding experiments and fatty acid biomarker analysis to characterize trophic dynamics and ecological roles of the 3 species, In feeding experiments, A. rara consumed a variety of co-occurring metazoans (several Crustacea, Mollusca, Echinodermata, and a Nephtys species). C. delacai, N. hyalinosphaira, and a number of other foraminiferal species from Explorers Cove successfully trapped Artemia sp. nauplius prey in a setup designed to examine the efficiency of prey capture. Fatty acid analyses on samples from early (November 7, 2001) and late (January 31, 2002) austral summer revealed that the 3 species contained substantial amounts (33 to 45.5%) of polyunsaturated fatty acids (PUFAs), which are produced by microalgae, indicating the downwards transfer of carbon from sea-ice associated primary production. In the case of A. rara, this may be due to the ingestion of herbivorous metazoa, rather than direct uptake of microalgal material. A. rara contained significantly (p < 0.05) higher amounts of the zooplankton biomarkers 20:1(n-9) and 22:1(n-11), and C. delacai contained more PUFAs early, compared to late, in the season. Two morphotypes of N. hyalinosphaira had different fatty acid Profiles, indicating distinct trophotypes. Our results illustrate specific adaptations to different trophic resources in these protists, and they demonstrate the potential impact that large carnivorous species of Foraminifera may have on the structure of benthic communities where they are abundant

    Nonstandard order parameters and the origin of CP violation

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    The consideration of chirality-preserving 2-fermion order parameters may shed new light on the strong CP problem and the breakdown of flavor symmetries. We describe two situations, one having the standard KM picture for weak CP violation and another having new sources of weak CP violation.Comment: 12 pages, no figure

    Medicines adherence: Involving patients in decisions about prescribed medicines and supporting adherence

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    It is thought that between a third and a half of all medicines1 There are many causes of non-adherence but they fall into two overlapping categories: intentional and unintentional. Unintentional non-adherence occurs when the patient wants to follow the agreed treatment but is prevented from doing so by barriers that are beyond their control. Examples include poor recall or difficulties in understanding the instructions, problems with using the treatment, inability to pay for the treatment, or simply forgetting to take it. prescribed for long-term conditions are not taken as recommended. If the prescription is appropriate, then this may represent a loss to patients, the healthcare system and society. The costs are both personal and economic. Adherence presumes an agreement between prescriber and patient about the prescriber’s recommendations. Adherence to medicines is defined as the extent to which the patient’s action matches the agreed recommendations. Non-adherence may limit the benefits of medicines, resulting in lack of improvement, or deterioration, in health. The economic costs are not limited to wasted medicines but also include the knock-on costs arising from increased demands for healthcare if health deteriorates. Non-adherence should not be seen as the patient’s problem. It represents a fundamental limitation in the delivery of healthcare, often because of a failure to fully agree the prescription in the first place or to identify and provide the support that patients need later on. Addressing non-adherence is not about getting patients to take more medicines per se. Rather, it starts with an exploration of patients’ perspectives of medicines and the reasons why they may not want or are unable to use them. Healthcare professionals have a duty to help patients make informed decisions about treatment and use appropriately prescribed medicines to best effec

    Detection of the heavy Higgs boson at γγ\gamma\gamma colliders

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    We consider the possibility of detecting a heavy Higgs boson (mH>2mZm_H>2m_Z) in proposed γγ\gamma\gamma colliders through the semi-leptonic mode γγHZZqqˉ+\gamma\gamma \rightarrow H \rightarrow ZZ \rightarrow q\bar q \ell^+\ell^-. We show that due to the non-monochromatic nature of the photon beams produced by the laser-backscattering method, the resultant cross section for Higgs production is much smaller than the on-resonance cross section and generally {\it decreases} with increasing collider energy. Although continuum ZZZZ production is expected to be negligible, we demonstrate the presence of and calculate sizeable backgrounds from γγ+Z,qqˉZ\gamma\gamma\rightarrow \ell^+\ell^-Z,\,q\bar qZ, with Zqqˉ,+Z\rightarrow q\bar q,\,\ell^+\ell^-, respectively, and γγttˉbbˉ+ννˉ\gamma\gamma\rightarrow t\bar t\rightarrow b\bar b\ell^+\ell^-\nu\bar\nu. This channel may be used to detect a Higgs of mass mHm_H up to around 350~GeV at a 0.5~TeV e+ee^+e^- collider, assuming a nominal yearly luminosity of 10--20~fb1^{-1}.Comment: 18 pages (in RevTeX) plus Postscript figures (available by email or FAX), NUHEP-TH-92-29 and DOE-309-CPP-47. (Revised version: NO CHANGES to the manuscript, simply removed corrupted figure files

    The Neutron Electric Dipole Moment and CP-violating Couplings in the Supersymmetric Standard Model without R-parity

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    We analyze the neutron electric dipole moment (EDM) in the Minimal Supersymmetric Model with explicit R-parity violating terms. The leading contribution to the EDM occurs at the 2-loop level and is dominated by the chromoelectric dipole moments of quarks, assuming there is no tree-level mixings between sleptons and Higgs bosons or between leptons and gauginos. Based on the experimental constraint on the neutron EDM, we set limits on the imaginary parts of complex couplings λijk{\lambda'}_{ijk} and λijk{\lambda}_{ijk} due to the virtual b-loop or tau-loop.Comment: final manuscript to appear in Phys. Rev. D, 15 pages, latex, 4 figures include

    The CP asymmetry for B--> K^* l^+ l^- decay in the general two Higgs doublet model

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    We study CP asymmetry for the exclusive decay B --> K^* l^+ l^- in the two Higgs doublet model with three level flavor changing neutral currents (model III). We analyse the dependency of this quantity to the new phase coming from the complex Yukawa couplings in the theory and we find that there exist a considerable CP violation for the relevant process. Further, we see that the sign of the Wilson coefficient C_7^{eff} can be determined by fixing dilepton mass. Therefore, the future measurements of CP asymmetry for B --> K^* l^+ l^- decay will give a powerful information about the sign of Wilson coefficient C_{7}^{eff} and the new physics beyond the SM.Comment: 22 pages, 8 figure

    CP Violation in Tau Slepton Pair Production at Muon Colliders

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    We discuss in detail signals for CP violation in the Higgs boson and tau-slepton sectors through the production processes μ+μτ~iτ~j+\mu^+\mu^- \to \tilde{\tau}_i^- \tilde{\tau}_j^+, where i,j=1,2i,j=1,2 label the two τ\tau slepton mass eigenstates in the minimal supersymmetric standard model. We assume that the soft breaking parameters of third generation sfermions contain CP violating phases, which induce CP violation in the Higgs sector through quantum corrections. We classify all the observables for probing CP violation in the Higgs boson and τ\tau slepton sectors. These observables depend on the initial muon beam polarization, where we include transverse polarization states. If the heavy Higgs bosons can decay into tau slepton pairs, a complete determination of the CP properties of the neutral Higgs boson and τ\tau--slepton systems is possible. The interference between the Higgs boson and gauge boson contributions could also provide a powerful method for probing CP violation, if transversely polarized muon beams are available. We show in detail how to directly measure CP violation in the tau slepton system, under the assumption that the neutral Higgs mixing angles are determined through the on--shell production of the neutral Higgs bosons.Comment: 38 pages, 9 figures Including 7 eps ones. A figure to show the dependence on tan(beta) and the mass parameters of the sfermion sectors and a reference added. To appear in Phys. Rev.

    Charm multiplicity and the branching ratios of inclusive charmless b quark decays in the general two-Higgs-doublet models

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    In the framework of general two-Higgs-doublet models, we calculate the branching ratios of various inclusive charmless b decays by using the low energy effective Hamiltonian including next-to-leading order QCD corrections, and examine the current status and the new physics effects on the determination of the charm multiplicity ncn_c and semileptonic branching ratio BSLB_{SL}. Within the considered parameter space, the enhancement to the ratio BR(bsg)BR(b \to s g) due to the charged-Higgs penguins can be as large as a factor of 8 (3) in the model III (II), while the ratio BR(bnocharm)BR(b \to no charm) can be increased from the standard model prediction of 2.49% to 4.91% (2.99%) in the model III (II). Consequently, the value of BSLB_{SL} and ncn_c can be decreased simultaneously in the model III. The central value of BSLB_{SL} will be lowered slightly by about 0.003, but the ratio ncn_c can be reduced significantly from the theoretical prediction of nc=1.28±0.05n_c= 1.28 \pm 0.05 in the SM to nc=1.23±0.05n_c= 1.23 \pm 0.05, 1.18±0.051.18 \pm 0.05 for mH+=200,100m_{H^+}=200, 100 GeV, respectively. We find that the predicted ncn_c and the measured ncn_c now agree within roughly one standard deviation after taking into account the effects of gluonic charged Higgs penguins in the model III with a relatively light charged Higgs boson.Comment: 25 pages, Latex file, axodraw.sty, 6 figures. Final version to be published in Phys.Rev.
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