1,851 research outputs found
Equivalence of Darmois-Israel and Distributional-Methods for Thin Shells in General Relativity
A distributional method to solve the Einstein's field equations for thin
shells is formulated. The familiar field equations and jump conditions of
Darmois-Israel formalism are derived. A carefull analysis of the Bianchi
identities shows that, for cases under consideration, they make sense as
distributions and lead to jump conditions of Darmois-Israel formalism.Comment: 17 pages Latex, no figures, to be published in Journ. Math. Phy
The effect of 12 weeks Anethum graveolens (dill) on metabolic markers in patients with metabolic syndrome; A randomized double blind controlled trial
Background: The clustering of metabolic abnormalities defined as metabolic syndrome is now both a public health and a clinical problem .While interest in herbal medicine has greatly increased, lack of human evidence to support efficacies shown in animals does exist. This clinical trial study designed to investigate whether herbal medicine, Anethum graveolens (dill) extract, could improve metabolic components in patients with metabolic syndrome. Methods: A double-blind, randomized, placebo-controlled trial using a parallel design was conducted. 24 subjects who had metabolic syndrome diagnostic criteria (update of ATP III) were randomly assigned to either dill extract (n = 12) or placebo (n = 12) for 3 months. Results: Across lipid component of metabolic syndrome, no significant differences in triglyceride (TG) concentration and high density lipoprotein cholesterol were seen between the two groups. However TG improved significantly from baseline (257.0 vs. 201.5p = 0.01) with dill treatment but such a significant effect was not observed in placebo group. Moreover, no significant differences in waist circumference, blood pressure and fasting blood sugar were seen between two groups after 3 months follow up period. Conclusion: In this small clinical trial in patients with metabolic syndrome, 12 weeks of dill extract treatment had a beneficial effect in terms of reducing TG from baseline. However dill treatment was not associated with a significant improvement in metabolic syndrome related markers compared to control group. Larger studies might be required to prove the efficacy and safety of long-Term administration of dill to resolve metabolic syndrome components. © 2012 Mansouri et al.; licensee BioMed Central Ltd
Matching LTB and FRW spacetimes through a null hypersurface
Matching of a LTB metric representing dust matter to a background FRW
universe across a null hypersurface is studied. In general, an unrestricted
matching is possible only if the background FRW is flat or open. There is in
general no gravitational impulsive wave present on the null hypersurface which
is shear-free and expanding. Special cases of the vanishing pressure or energy
density on the hypersurface is discussed. In the case of vanishing energy
momentum tensor of the null hypersurface, i.e. in the case of a null boundary,
it turns out that all possible definitions of the Hubble parameter on the null
hypersurface, being those of LTB or that of FRW, are equivalent, and that a
flat FRW can only be joined smoothly to a flat LTB.Comment: 9 page
The Modify Version of Artificial Bee Colony Algorithm to solve Real Optimization problems
The Artificial Bee Colony(ABC) algorithm is one of the best applicableoptimization algorithm. In this work, we make some modifications toimprove the ABC algorithm based on convergence speed of solution. Inorder to, we add some conditions to selected food sources by bees. So, ifsolution have been enough near to optimal solution, then further search existaround the food sources. That, this is near to optimal solution because, wecan replace lower and upper bounds of food sources with smaller valuesrelate to last search. Therefore, the new search is near to optimal solution and after some iteration, optimal solution achieves. Finally, we illustrateconvergence speed of the MABC algorithm that is faster than ABCalgorithm. There are some examples.DOI:http://dx.doi.org/10.11591/ijece.v2i4.42
Early mesodermal phenotypes in splotch suggest a role for Pax3 in the formation of epithelial somites
Thick planar domain wall: its thin wall limit and dynamics
We consider a planar gravitating thick domain wall of the
theory as a spacetime with finite thickness glued to two vacuum spacetimes on
each side of it. Darmois junction conditions written on the boundaries of the
thick wall with the embedding spacetimes reproduce the Israel junction
condition across the wall in the limit of infinitesimal thickness. The thick
planar domain wall located at a fixed position is then transformed to a new
coordinate system in which its dynamics can be formulated. It is shown that the
wall's core expands as if it were a thin wall. The thickness in the new
coordinates is not constant anymore and its time dependence is given.Comment: 11 pages, to appear in IJMP
Radiation from the LTB black hole
Does a dynamical black hole embedded in a cosmological FRW background emit
Hawking radiation where a globally defined event horizon does not exist? What
are the differences to the Schwarzschild black hole? What about the first law
of black hole mechanics? We face these questions using the LTB cosmological
black hole model recently published. Using the Hamilton-Jacobi and radial null
geodesic-methods suitable for dynamical cases, we show that it is the apparent
horizon which contributes to the Hawking radiation and not the event horizon.
The Hawking temperature is calculated using the two different methods giving
the same result. The first law of LTB black hole dynamics and the thermal
character of the radiation is also dealt with.Comment: 9 pages, revised version, Europhysics Letter 2012 97 2900
A Review of Biologic Therapies Targeting IL-23 and IL-17 for Use in Moderate-to-Severe Plaque Psoriasis
International audienceThis paper presents numerical crack propagations in case of explicit dynamics, and applied to eXtended Finite Element Method. The interest of this method is non remeshing. Hence the crack propagates through the constant mesh. Only some elements cut by the crack can have critical time step close to zero. To avoid this case, the lumping technique of mass matrix will allow to obtain the same critical time step than the case without crack: a crack and its propagation do not modify the critical time step of the whole structure. To conclude, we have for some elements.Ce papier traite de la simulation numérique de propagation dynamique de fissure dans le cas particulier de calcul explicite, et appliquée à la méthode des éléments finis étendus. L'intérêt de cette méthode est le non-remaillage. Effectivement, la fissure se propage dans le maillage invariant. Seulement certains éléments, coupés par la fissure, peuvent avoir des pas de temps critiques de calcul presque nuls. Pour s'affranchir de ces cas pénalisant le calcul, la méthode de diagonalisation de matrice de masse va permettre d'obtenir le même pas de temps critique que le cas sans fissure : l'introduction d'une fissure et sa propagation ne modifie pas le pas de temps critique de la structure. Au final, on a dans certains cas
Investigation of phonon behavior in Pr2NiMnO6 by micro-Raman spectroscopy
The temperature dependence of phonon excitations and the presence of spin
phonon coupling in polycrystalline Pr2NiMnO6 samples were studied using
micro-Raman spectroscopy and magnetometry. Magnetic properties show a single
ferromagnetic-to-paramagnetic transition at 228 K and a saturation
magnetization close to 4.95 \muB/f.u.. Three distinct Raman modes at 657, 642,
and 511 cm-1 are observed. The phonon excitations show a clear hardening due to
anharmonicity from 300 K down to 10 K. Further, temperature dependence of the
657 cm-1 mode shows only a small softening. This reflects the presence of a
relatively weak spin-phonon coupling in Pr2NiMnO6 contrary to other double
perovskites previously studied.Comment: 10 pages, 4 fig
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