Serum and Liver Iron Differently Regulate the Bone Morphogenetic Protein 6 (BMP6)-SMAD Signaling Pathway in Mice

The bone morphogenetic protein 6 (BMP6)-SMAD signaling pathway is a central regulator of hepcidin expression and systemic iron balance. However, the molecular mechanisms by which iron is sensed to regulate BMP6-SMAD signaling and hepcidin expression are unknown. Here we examined the effects of circulating and tissue iron on Bmp6-Smad pathway activation and hepcidin expression in vivo after acute and chronic enteral iron administration in mice. We demonstrated that both transferrin saturation and liver iron content independently influence hepcidin expression. Although liver iron content is independently positively correlated with hepatic Bmp6 messenger RNA (mRNA) expression and overall activation of the Smad1/5/8 signaling pathway, transferrin saturation activates the downstream Smad1/5/8 signaling cascade, but does not induce Bmp6 mRNA expression in the liver. Hepatic inhibitory Smad7 mRNA expression is increased by both acute and chronic iron administration and mirrors overall activation of the Smad1/5/8 signaling cascade. In contrast to the Smad pathway, the extracellular signal-regulated kinase 1 and 2 (Erk1/2) mitogen-activated protein kinase (Mapk) signaling pathway in the liver is not activated by acute or chronic iron administration in mice. Conclusion: Our data demonstrate that the hepatic Bmp6-Smad signaling pathway is differentially activated by circulating and tissue iron to induce hepcidin expression, whereas the hepatic Erk1/2 signaling pathway is not activated by iron in vivo

Higgs algebraic symmetry of screened system in a spherical geometry

The orbits and the dynamical symmetries for the screened Coulomb potentials and isotropic harmonic oscillators have been studied by Wu and Zeng [Z. B. Wu and J. Y. Zeng, Phys. Rev. A 62,032509 (2000)]. We find the similar properties in the responding systems in a spherical space, whose dynamical symmetries are described by Higgs Algebra. There exists a conserved aphelion and perihelion vector, which, together with angular momentum, constitute the generators of the geometrical symmetry group at the aphelia and perihelia points $(\dot{r}=0)$.Comment: 8 pages, 1 fi

Large time existence for 3D water-waves and asymptotics

We rigorously justify in 3D the main asymptotic models used in coastal oceanography, including: shallow-water equations, Boussinesq systems, Kadomtsev-Petviashvili (KP) approximation, Green-Naghdi equations, Serre approximation and full-dispersion model. We first introduce a ``variable'' nondimensionalized version of the water-waves equations which vary from shallow to deep water, and which involves four dimensionless parameters. Using a nonlocal energy adapted to the equations, we can prove a well-posedness theorem, uniformly with respect to all the parameters. Its validity ranges therefore from shallow to deep-water, from small to large surface and bottom variations, and from fully to weakly transverse waves. The physical regimes corresponding to the aforementioned models can therefore be studied as particular cases; it turns out that the existence time and the energy bounds given by the theorem are always those needed to justify the asymptotic models. We can therefore derive and justify them in a systematic way.Comment: Revised version of arXiv:math.AP/0702015 (notations simplified and remarks added) To appear in Inventione

Potts model on recursive lattices: some new exact results

We compute the partition function of the Potts model with arbitrary values of $q$ and temperature on some strip lattices. We consider strips of width $L_y=2$, for three different lattices: square, diced and `shortest-path' (to be defined in the text). We also get the exact solution for strips of the Kagome lattice for widths $L_y=2,3,4,5$. As further examples we consider two lattices with different type of regular symmetry: a strip with alternating layers of width $L_y=3$ and $L_y=m+2$, and a strip with variable width. Finally we make some remarks on the Fisher zeros for the Kagome lattice and their large q-limit.Comment: 17 pages, 19 figures. v2 typos corrected, title changed and references, acknowledgements and two further original examples added. v3 one further example added. v4 final versio

Overcoming controllability problems in distributed testing from an input output transition system

This is the Pre-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2012 Springer VerlagThis paper concerns the testing of a system with physically distributed interfaces, called ports, at which it interacts with its environment. We place a tester at each port and the tester at port p observes events at p only. This can lead to controllability problems, where the observations made by the tester at a port p are not sufficient for it to be able to know when to send an input. It is known that there are test objectives, such as executing a particular transition, that cannot be achieved if we restrict attention to test cases that have no controllability problems. This has led to interest in schemes where the testers at the individual ports send coordination messages to one another through an external communications network in order to overcome controllability problems. However, such approaches have largely been studied in the context of testing from a deterministic finite state machine. This paper investigates the use of coordination messages to overcome controllability problems when testing from an input output transition system and gives an algorithm for introducing sufficient messages. It also proves that the problem of minimising the number of coordination messages used is NP-hard

Evidence for softening of first-order transition in 3D by quenched disorder

We study by extensive Monte Carlo simulations the effect of random bond dilution on the phase transition of the three-dimensional 4-state Potts model which is known to exhibit a strong first-order transition in the pure case. The phase diagram in the dilution-temperature plane is determined from the peaks of the susceptibility for sufficiently large system sizes. In the strongly disordered regime, numerical evidence for softening to a second-order transition induced by randomness is given. Here a large-scale finite-size scaling analysis, made difficult due to strong crossover effects presumably caused by the percolation fixed point, is performed.Comment: LaTeX file with Revtex, 4 pages, 4 eps figure

Superconducting properties of RuSr2GdCu2O8 studied by SQUID magnetometry

For polycrystalline RuSr2GdCu2O8 (Ru-1212), distinct peaks have been reported in d.c. magnetization in the superconducting state of the sample. Sr2GdRuO6 (Sr-2116), the precursor for the preparation of Ru-1212, shows similar peaks in the same temperature regime. Based on measurements performed on both bulk and powdered samples of Ru-1212 and Sr-2116, we exclude the possibility, that the observed behavior of the magnetization of Ru-1212 is due to Sr-2116 impurities. The effect is related to the superconductivity of Ru-1212, but it is not an intrinsic property of this compound. We provide evidence that the observation of magnetization peaks in the superconducting state of Ru-1212 is due to flux motion generated by the movement of the sample in an inhomogeneous field, during the measurement in the SQUID magnetometer. We propose several tests, that help to decide, whether the features observed in a SQUID magnetization measurement of Ru-1212 represent a property of the compound or not.Comment: 22 pages, 9 figure

Observational Constraints of Modified Chaplygin Gas in Loop Quantum Cosmology

We have considered the FRW universe in loop quantum cosmology (LQC) model filled with the dark matter (perfect fluid with negligible pressure) and the modified Chaplygin gas (MCG) type dark energy. We present the Hubble parameter in terms of the observable parameters $\Omega_{m0}$, $\Omega_{x0}$ and $H_{0}$ with the redshift $z$ and the other parameters like $A$, $B$, $C$ and $\alpha$. From Stern data set (12 points), we have obtained the bounds of the arbitrary parameters by minimizing the $\chi^{2}$ test. The best-fit values of the parameters are obtained by 66%, 90% and 99% confidence levels. Next due to joint analysis with BAO and CMB observations, we have also obtained the bounds of the parameters ($B,C$) by fixing some other parameters $\alpha$ and $A$. From the best fit of distance modulus $\mu(z)$ for our theoretical MCG model in LQC, we concluded that our model is in agreement with the union2 sample data.Comment: 14 pages, 10 figures, Accepted in EPJC. arXiv admin note: text overlap with arXiv:astro-ph/0311622 by other author

Muon anomalous magnetic moment in the standard model with two Higgs doublets

The muon anomalous magnetic moment is investigated in the standard model with two Higgs doublets (S2HDM) motivated from spontaneous CP violation. Thus all the effective Yukawa couplings become complex. As a consequence of the non-zero phase in the couplings, the one loop contribution from the neutral scalar bosons could be positive and negative relying on the CP phases. The interference between one and two loop diagrams can be constructive in a large parameter space of CP-phases. This will result in a significant contribution to muon anomalous magnetic moment even in the flavor conserving process with a heavy neutral scalar boson ($m_h \sim$ 200 GeV) once the effective muon Yukawa coupling is large ($|\xi_\mu|\sim 50$). In general, the one loop contributions from lepton flavor changing scalar interactions become more important. In particular, when all contributions are positive in a reasonable parameter space of CP phases, the recently reported 2.6 sigma experiment vs. theory deviation can be easily explained even for a heavy scalar boson with a relative small Yukawa coupling in the S2HDM.Comment: 8 pages, RevTex file, 5 figures, published version Phys. Rev. D 54 (2001) 11501

A New Triangular Hybrid Displacement Function Element for Static and Free Vibration Analyses of Mindlin-Reissner Plate

A new 3-node triangular hybrid displacement function Mindlin- Reissner plate element is developed. Firstly, the modified variational functional of complementary energy for Mindlin-Reissner plate, which is eventually expressed by a so-called displacement function F, is proposed. Secondly, the locking-free formulae of Timoshenko’s beam theory are chosen as the deflection, rotation, and shear strain along each element boundary. Thirdly, seven fundamental analytical solutions of the displacement function F are selected as the trial functions for the assumed resultant fields, so that the assumed resultant fields satisfy all governing equations in advance. Finally, the element stiffness matrix of the new element, denoted by HDF-P3-7β, is derived from the modified principle of complementary energy. Together with the diagonal inertia matrix of the 3-node triangular isoparametric element, the proposed element is also successfully generalized to the free vibration problems. Numerical results show that the proposed element exhibits overall remarkable performance in all benchmark problems, especially in the free vibration analyses