14,404 research outputs found

    B_s^0 - bar{B}_s^0 Mixing and the B_s -> J/psi phi Asymmetry in Supersymmetric Models

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    We analyse supersymmetric contributions to B_s mixing and their impact on mixing-induced CP asymmetries, using the mass insertion approximation. We discuss in particular the correlation of SUSY effects in the CP asymmetries of B_s -> J/psi phi and B_d -> phi K_S and find that the mass insertions dominant in B_s mixing and B_d -> phi K_S are (delta_{23}^d)_{LL, RR} and (delta_{23}^d)_{LR, RL}, respectively. We show that models with dominant (delta_{23}^d)_{LR, RL} can accomodate a negative value of S_{phi K_S}, in agreement with the BELLE measurement of that observable, but yield a B_s mixing phase too small to be observed. On the other hand, models with dominant (delta_{23}^d)_{LL, RR} predict sizeable SUSY contributions to both Delta M_s and the mixing phase, but do not allow the asymmetry in B_d -> phi K_S to become negative, except for small values of the average down squark mass, which, in turn, entail a value of Delta M_s too large to be observed at the Tevatron and the LHC. We conclude that the observation of B_s mixing at hadron machines, together with the confirmation of a negative value of S_{phi K_S}, disfavours models with a single dominant mass insertion.Comment: 17 pages, 5 figure

    Targeting ATM pathway for therapeutic intervention in cancer

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    The Ataxia Telangiectasia Mutated gene encodes the ATM protein, a key element in the DNA damage response (DDR) signalling pathway responsible for maintaining genomic integrity within the cell. The ATM protein belongs to a family of large protein kinases containing the phosphatidylinositol-3 catalytic domain, including ATM, ATR and PI3K. ATM provides the crucial link between DNA damage, cell cycle progression and cell death by first sensing double stranded DNA breaks and subsequently phosphorylating and activating other downstream proteins functioning in DNA damage repair, cell cycle arrest and apoptotic pathways,. Mammalian cells are constantly challenged by genotoxic agents from a variety of sources and therefore require a robust sensing and repair mechanism to maintain DNA integrity or activate alternative cell fate pathways. This review covers the role of ATM in DDR signalling and describes the interaction of the ATM kinase with other proteins in order to fulfil its various functions. Special emphasis is given to how the growing knowledge of the DDR can help identify drug targets for cancer therapy, thus providing a rationale for exploiting the ATM pathway in anticancer drug development. Moreover, we discuss how a network modelling approach can be used to identify and characterise ATM inhibitors and predict their therapeutic potential

    The Use of Local Mineral Formulas as a Feed Block Supplement for Beef Cattle Fed on Wild Forages

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    The present research was carried out to study the diversity of mineral contents of wild forages and to evaluate the beneficial effect of mineral feed supplement formulated by using locally available materials on the performances of beef cattle. The present research was initiated by analyzing mineral contents of wild forages grown around Limau Manis campus areas. Forage samples were collected at 9 sampling areas scattered at plantation, conservation and idle lands. Samples were then analyzed for macro minerals of Ca, P, Mg, K, Na, and S and micro minerals of Co, Cu, Fe, Mn, Se, and Zn. Feeding trial was then conducted to evaluate the beneficial effect of supplementation of local mineral formulas (LMF) produced by using locally available materials on the performances of cattle. Feeding trial was conducted for 6 weeks by using 9 Simmentals cross bred heifers. The trial consisted of 3 treatments, i.e., P1: only grass without supplementation, P2: grass + LMF and P3: grass + mineral premix enriched LMF. Variables measured were: body weight, feed intake, FCR, feed cost and net return. Results showed that the highest macro mineral content of wild forages was Na of about 13.05±2.22 g/kg, varied from 4.1 to 23.8 g/kg, followed by K (11.09±1.43 g/kg) and Ca (6.10±1.09 g/kg DM). Three minerals of Mg, P, and S were found in relatively small concentrations of 1.34±0.30, 0.83±0.23, and 0.17±0.01 g/kg, respectively. Fe, Mn, Cu and Zn were found in relatively high concentrations. The highest concentration of micro minerals was Fe of about 613.8±128.9 mg/kg, followed by Mn of 143.9±23.3 mg/kg, while Zn and Cu were found in relatively small amount of about 31.3±5.5 and 13.2±2.5 mg/kg, respectively. Heifers supplemented with LMF (P2) and mineral premix enriched LMF (P3) showed higher body weight gain, lower FCR and net return than those cattle fed only grass (P1). The most profitable feeding strategy was by supplementation of heifers with mineral premix enriched LMF.Key words: wild forage quality, local mineral formula, ruminant mineral nutritio

    Criticality of natural absorbing states

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    We study a recently introduced ladder model which undergoes a transition between an active and an infinitely degenerate absorbing phase. In some cases the critical behaviour of the model is the same as that of the branching annihilating random walk with N≥2N\geq 2 species both with and without hard-core interaction. We show that certain static characteristics of the so-called natural absorbing states develop power law singularities which signal the approach of the critical point. These results are also explained using random walk arguments. In addition to that we show that when dynamics of our model is considered as a minimum finding procedure, it has the best efficiency very close to the critical point.Comment: 6 page

    Quantitative analysis of NRF2 pathway reveals key elements of the regulatory circuits underlying antioxidant response and proliferation of ovarian cancer cells

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    Cells are constantly exposed to Reactive Oxygen Species (ROS) produced both endogenously to meet physiological requirements and from exogenous sources. While endogenous ROS are considered as important signalling molecules, high uncontrollable ROS are detrimental. It is unclear how cells can achieve a balance between maintaining physiological redox homeostasis and robustly activate the antioxidant system to remove exogenous ROS. We have utilised a Systems Biology approach to understand how this robust adaptive system fulfils homeostatic requirements of maintaining steady-state ROS and growth rate, while undergoing rapid readjustment under challenged conditions. Using a panel of human ovarian and normal cell lines, we experimentally quantified and established interrelationships between key elements of ROS homeostasis. The basal levels of NRF2 and KEAP1 were cell line specific and maintained in tight correlation with their growth rates and ROS. Furthermore, perturbation of this balance triggered cell specific kinetics of NRF2 nuclear–cytoplasmic relocalisation and sequestration of exogenous ROS. Our experimental data were employed to parameterise a mathematical model of the NRF2 pathway that elucidated key response mechanisms of redox regulation and showed that the dynamics of NRF2-H2O2 regulation defines a relationship between half-life, total and nuclear NRF2 level and endogenous H2O2 that is cell line specific

    Magnetic Response of Magnetospirillum Gryphiswaldense

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    In this study we modelled and measured the U-turn trajectories of individual magnetotactic bacteria under the application of rotating magnetic fields, ranging in ampitude from 1 to 12 mT. The model is based on the balance between rotational drag and magnetic torque. For accurate verification of this model, bacteria were observed inside 5 m tall microfluidic channels, so that they remained in focus during the entire trajectory. From the analysis of hundreds of trajectories and accurate measurements of bacteria and magnetosome chain dimensions, we confirmed that the model is correct within measurement error. The resulting average rate of rotation of Magnetospirillum Gryphiswaldense is 0.74 +- 0.03 rad/mTs.Comment: 17 pages, 12 figure

    Muon Anomalous Magnetic Moment and mu -> e gamma in B-L Model with Inverse Seesaw

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    We study the anomalous magnetic moment of the muon, a_\mu, and lepton flavor violating decay \mu -> e \gamma in TeV scale B-L extension of the Standard Model (SM) with inverse seesaw mechanism. We show that the B-L contributions to a_\mu are severely constrained, therefore the SM contribution remains intact. We also emphasize that the current experimental limit of BR(\mu -> e \gamma) can be satisfied for a wide range of parameter space and it can be within the reach of MEG experiment.Comment: 10 pages, 4 Figure
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