454 research outputs found

    Turner/Down mosaicism: A case report

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    A 45,X/47,XX, +21 mosaicism (80%:20%) in a young girl with clinical features of Down syndrome is reported. The proportion of 45,X:47,XX, +21 cells present in peripheral lymphocytes does not necessarily have a profound effect on the phenotype. A possible explanation for the occurrence of double aneuploidy is given

    Dynamical density functional theory for the evaporation of droplets of nanoparticle suspension

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    We develop a lattice gas model for the drying of droplets of a nanoparticle suspension on a planar surface, using dynamical density functional theory (DDFT) to describe the time evolution of the solvent and nanoparticle density profiles. The DDFT assumes a diffusive dynamics but does not include the advective hydrodynamics of the solvent, so the model is relevant to highly viscous or near to equilibrium systems. Nonetheless, we see an equivalent of the coffee-ring stain effect, but in the present model it occurs for thermodynamic rather the fluid-mechanical reasons. The model incorporates the effect of phase separation and vertical density variations within the droplet and the consequence of these on the nanoparticle deposition pattern on the surface. We show how to include the effect of slip or no-slip at the surface and how this is related to the receding contact angle. We also determine how the equilibrium contact angle depends on the microscopic interaction parameters.Comment: 35 pages, 10 figure

    The effects of divergent selection for reproduction and sex on quantitative and qualitative slaughter traits in Merinos

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    The impact of selection of sheep for reproduction on meat traits are not evident, while genetic parameters for meat traits is absent for South African pure breeds. Quantitative and qualitative meat traits were therefore studied in progeny of two Merino selection lines that were divergently selected for number of lambs weaned per ewe joined (NLW) since 1986. The historic divergent selection resulted in two lines (High (H) and Low (L)) differing widely for NLW. Slaughter data were recorded during the routine slaughter of surplus 14-month-old ram and ewe hoggets from these lines and assessed for selection line and sex. Single-trait heritability estimates were derived for meat traits by average information restricted maximum likelihood methods. Depending on the trait, data were available for between 340 and 576 animals that were recorded between 2015 and 2018. Hoggets from the H line were heavier than their L line contemporaries, with a slightly lower ultimate pH after 48 h in the cooler and slightly darker meat. H line ewes had, on average, redder meat than the other selection line x sex groups. Single-trait heritability estimates amounted to 0.44 ± 0.16 for slaughter weight, 0.63 ± 0.15 for carcass weight, 0.34 ± 0.15 for dressing percentage, 0.25 ± 0.11 for fat depth at the 13th rib, 0.29 ± 0.11 for fat depth at the rump, 0.12 ± 0.11 for ultimate pH, 0.32 ± 0.12 for lightness, 0.11 ± 0.09 for redness, 0.04 ± 0.06 for yellowness, 0.05 ± 0.08 for cooking loss and 0.06 ± 0.07 for drip loss. Parameter estimates for initial pH and shear force of the meat went to the boundary of parameter space and were not estimable. It was concluded that selection for NLW did not compromise any of the meat traits and that most quantitative meat traits were heritable and variable, making selection for improvement of these traits feasible. Additional research is indicated on the qualitative meat traits studied.Cape Wools SA, Red Meat Research and Development SA, the Research Technology Fund, as well as from the Western Cape Agricultural Research Trust.https://www.elsevier.com/locate/smallrumreshj2022Animal and Wildlife Science

    Analysis of Various Polarization Asymmetries In The Inclusive b→sℓ+ℓ−b\to s \ell^+ \ell^- Decay In The Fourth-Generation Standard Model

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    In this study a systematical analysis of various polarization asymmetries in inclusive b \rar s \ell^+ \ell^- decay in the standard model (SM) with four generation of quarks is carried out. We found that the various asymmetries are sensitive to the new mixing and quark masses for both of the μ\mu and τ\tau channels. Sizeable deviations from the SM values are obtained. Hence, b \rar s \ell^+ \ell^- decay is a valuable tool for searching physics beyond the SM, especially in the indirect searches for the fourth-generation of quarks (t′,b′)t', b').Comment: 19 Pages, 10 Figures, 3 Table

    Modeling electrolytically top gated graphene

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    We investigate doping of a single-layer graphene in the presence of electrolytic top gating. The interfacial phenomena is modeled using a modified Poisson-Boltzmann equation for an aqueous solution of simple salt. We demonstrate both the sensitivity of graphene's doping levels to the salt concentration and the importance of quantum capacitance that arises due to the smallness of the Debye screening length in the electrolyte.Comment: 7 pages, including 4 figures, submitted to Nanoscale Research Letters for a special issue related to the NGC 2009 conference (http://asdn.net/ngc2009/index.shtml

    Study of Bs-> \phi l^+ l^-$ Decay in a Single Universal Extra Dimension

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    Utilizing form factors calculated within the light-cone sum rules, we have evaluated the decay branching ratios of Bs→ϕγB_s\to \phi\gamma and Bs→ϕℓ+ℓ−B_s\to \phi \ell^+\ell^- in a single universal extra dimension model (UED), which is viewed as one of the alternative theories beyond the standard model (SM). For the decay Bs→ϕℓ+ℓ−B_s \to \phi \ell^+\ell^-, the dilepton invariant mass spectra, the forward-backward asymmetry, and double lepton polarization are also calculated. For each case, we compared the obtained results with predictions of the SM. In lower values of the compactification factor 1/R, the only parameter in this model, we see the considerable discrepancy between the UED and SM models. However, when 1/R increases, the results of UED tend to diminish and at 1/R=1000GeV1/R = 1000 \mathrm{GeV}, two models have approximately the same predictions. Compared with data from CDF of Bs→ϕμ+μ−B_s \to \phi \mu^+ \mu^-, the 1/R tends to be larger than 350GeV350 \mathrm{GeV}. We also note that the zero crossing point of the forward-backward asymmetry is become smaller, which will be an important plat to prob the contribution from the extra dimension model. The results obtained in this work will be very useful in searching new physics beyond SM. Moreover, the order of magnitude for branching ratios shows a possibility to study these channels at the Large Hadron Collider (LHC), CDF and the future super-B factory.Comment: 13 pages, 16 figure

    Lepton Polarization and Forward-Backward Asymmetries in b -> s tau+ tau-

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    We study the spin polarizations of both tau leptons in the decay b -> s tau+ tau-. In addition to the polarization asymmetries involving a single tau, we construct asymmetries for the case where both polarizations are simultaneously measured. We also study forward-backward asymmetries with polarized tau's. We find that a large number of asymmetries are predicted to be large, >~ 10%. This permits the measurement of all Wilson coefficients and the b-quark mass, thus allowing the standard model (SM) to be exhaustively tested. Furthermore, there are many unique signals for the presence of new physics. For example, asymmetries involving triple-product correlations are predicted to be tiny within the SM, O(10^{-2}). Their observation would be a clear signal of new physics.Comment: 21 pages, LaTeX, 4 figures (included). Paper somewhat reorganized, references greatly expanded, conclusions unchange

    B_s --> mu+ mu- decay in the R-parity violating minimal supergravity

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    We study B_s --> mu+ mu- in the context of the R-parity violating minimal supergravity in the high tan beta regime. We find that the lowest value of the branching ratio can go well below the present LHCb sensitivity and hence B_s --> mu+ mu- can even be invisible to the LHC. We also find that the present upper bound on Br(B_s --> mu+ mu-) puts strong constraint on the minimal supergravity parameter space. The constraints become more severe if the upper bound is close to its standard model prediction.Comment: 18 pages, 10 figures; version to be published in European Physical Journal

    From Violation to Reconstruction: The Process of Self-Renewal Associated with Chronic Fatigue Syndrome

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    Chronic Fatigue Syndrome (CFS) is a contested condition that generates scepticism and occupies a marginalised position within medical and social contexts. The thesis examines the illness experiences, and specifically the experiences of self, for people affected with CFS. Using qualitative inquiry, a substantive theory related to the process of self-renewal and adaptation associated with CFS is explicated. The theory encompasses the trajectory of CFS from onset to chronicity, and in exceptional instances, recovery. Illness narratives were derived from in-depth, semi-structured interviews of 19 adults, including 16 people affected with, and 3 people recovered from, CFS. Data was coded and analysed using a grounded theory approach. Analysis generated two parallel narratives that defined the illness experience of CFS: the narrative of the illness biographies and the narrative of self, specifically the struggling and diminished self seeking renewal. The illness biographies encompassed the stories of symptoms and their explanations, the encounters that ensued and their contentious milieu. The narrative of self was the primary narrative. It articulated the negative consequences to self and personhood associated with CFS, named the Violation of Self, and the consequent efforts of participants to decrease the struggle and violation by use of the Guardian Response and the Reconstructing Response. The Guardian Response provided protection and self-reclamation. The Reconstructing Response fostered self-renewal and meaning. The two narratives were bridged by the threats of CFS. That is, the illness biographies were accompanied by threats of disruption related to chronic illness, and by threats of invalidation that arose from CFS as a contested condition. In turn, these threats provided the catalyst to the violation and responses as described in the narrative of self. Under different conditions the relative strengths of violation, guardianship or reconstruction fluctuated, and it was these fluctuations that presented the participants with the ongoing struggle of CFS

    Exploring flavor structure of supersymmetry breaking from rare B decays and unitarity triangle

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    We study effects of supersymmetric particles in various rare B decay processes as well as in the unitarity triangle analysis. We consider three different supersymmetric models, the minimal supergravity, SU(5) SUSY GUT with right-handed neutrinos, and the minimal supersymmetric standard model with U(2) flavor symmetry. In the SU(5) SUSY GUT with right-handed neutrinos, we consider two cases of the mass matrix of the right-handed neutrinos. We calculate direct and mixing-induced CP asymmetries in the b to s gamma decay and CP asymmetry in B_d to phi K_S as well as the B_s--anti-B_s mixing amplitude for the unitarity triangle analysis in these models. We show that large deviations are possible for the SU(5) SUSY GUT and the U(2) model. The pattern and correlations of deviations from the standard model will be useful to discriminate the different SUSY models in future B experiments.Comment: revtex4, 36 pages, 10 figure
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