Holographic dark energy in Brans-Dicke cosmology with Granda-Oliveros cut-off

Motivated by the recent works of one of us [1,2] we study the holographic dark energy in Brans-Dicke gravity with the Granda-Oliveros cut-off proposed recently in literature. We find out that when the present model is combined with Brans-Dicke field the transition from normal state where $w_D >-1$ to the phantom regime where $w_D <-1$ for the equation of state of dark energy can be more easily achieved for than when resort to the Einstein field equations is made. Furthermore, the phantom crossing is more easily achieved when the matter and the holographic dark energy undergo an exotic interaction. We also calculate some relevant cosmological parameters and their evolution.Comment: 10 pages, accepted for publication in IJT

Teleparallel Killing Vectors of the Einstein Universe

In this short paper we establish the definition of the Lie derivative of a second rank tensor in the context of teleparallel theory of gravity and also extend it for a general tensor of rank $p+q$. This definition is then used to find Killing vectors of the Einstein universe. It turns out that Killing vectors of the Einstein universe in the teleparallel theory are the same as in General Relativity.Comment: 9 pages, accepted for publication in Mod. Phys. Lett.

Constraints on coupling constant between dark energy and dark matter

We have investigated constraints on the coupling between dark matter and the interacting Chaplygin gas. Our results indicate that the coupling constant $c$ between these two entities can take arbitrary values, which can be either positive or negative, thus giving arbitrary freedom to the inter-conversion between Chaplygin gas and dark matter. Thus our results indicate that the restriction $0<c<1$ on the coupling constant occurs as a very special case. Our analysis also supports the existence of phantom energy under certain conditions on the coupling constant.Comment: 16 Pages, 3 figure

Generalized Holographic Dark Energy Model

In this paper, the model of holographic Chaplygin gas has been extended to two general cases: first is the case of modified variable Chaplygin gas and secondly of the viscous generalized Chaplygin gas. The dynamics of the model are expressed by the use of scalar fields and the scalar potentials.Comment: 12 pages, to appear in Eur. Phys. J.

Aktivitas Antimikroba Ekstrak Biji Nigella Sativa Terhadap Viabilitas Bakteri Probiotik Secara in Vitro Dan in Vivo

Nigella sativa has a lot of pharmacological activities. One of those is the broad range antimicrobial activity. The aims of this research are to find out the antimicrobial activity against probiotic bacteria as normal flora in gastrointestinal track (GIT), in order to determine the apropriate dose which not harm for GIT normal flora. This research was conducted by in vitro and invivo assay. In vitro assay for antimicrobial acitivity using disc diffusion method with n-hexane, ethyl acetate and ethanol fraction of N. sativa extract. The concentration of each fraction were varied into 500 mg/ml; 250 mg/ml; 125 mg/ml; 62.5 mg/ml, 31.25 mg/ml, 15.625 mg/ml, respectively. In vivo assay using mice (Mus musculus) to analyze the difference of the probiotic bacteria viability in the GIT of treated mice and in that of control mice. N. sativa extract at dose of 1.3 mg/20gBW, 2.6 mg/20gBW, and 3.9 mg/20gBW were used as adjuvant with sefadroxil 1,3 mg/20 g BB. The result showed that the n-hexane extract possessing the highest potency as antimicrobial against probiotic bacteria, wich the minimum inhibitory concentration was 15,625 mg/ml. The in vivo assay shows that the dose of 1.3 mg/20gBW of mice has antimicrobial activity and so do the higher doses. Key words: antimicrobial, probiotic bacteria, N. sativa, in vivo, in vitr

Experimental study of helical milling on CFRP (carbon fibre reinforced polymer) for the hole making process

Generate borehole by helical milling process may be used effectively since accurate location of the hole may be secured by means of the feed screw graduations. Fiber delamination which is the main defect occurred during hole making process on carbon fiber reinforced polymer (CFRP) were investigate throughout an experimental study. Effects of thrust force (Fz), delamination factor (Fd) and surface roughness are evaluated. Objective of the experiment are to find best cutting parameter and tool design suitable to performed helical milling operation on CFRP. Two types of end mill with 4 flutes were used and results are evaluated. It was found that tool design 2-1 has higher performance on CFRP

Interacting Generalised Cosmic Chaplygin gas in Loop quantum cosmology: A singularity free universe

In this work we investigate the background dynamics when dark energy is coupled to dark matter with a suitable interaction in the universe described by Loop quantum cosmology. Dark energy in the form of Generalised Cosmic Chaplygin gas is considered. A suitable interaction between dark energy and dark matter is taken into account in order to at least alleviate (if not solve) the cosmic coincidence problem. The dynamical system of equations is solved numerically and a stable scaling solution is obtained. A significant attempt towards the solution of the cosmic coincidence problem is taken. The statefinder parameters are also calculated to classify the dark energy model. Graphs and phase diagrams are drawn to study the variations of these parameters. It is seen that the background dynamics of Generalised Cosmic Chaplygin gas is completely consistent with the notion of an accelerated expansion in the late universe. From the graphs, generalised cosmic Chaplygin gas is identified as a dark fluid with a lesser negative pressure compared to Modified Chaplygin gas, thus supporting a 'No Big Rip' cosmology. It has also been shown that in this model the universe follows the power law form of expansion around the critical point, which is consistent with the known results. Future singularities that may be formed in this model as an ultimate fate of the universe has been studied in detail. It was found that the model is completely free from any types of future singularities.Comment: 10 pages, 10 figures. arXiv admin note: text overlap with arXiv:1109.1481, arXiv:1102.275

Interacting entropy-corrected new agegraphic dark energy in Brans-Dicke cosmology

Motivated by a recent work of one of us [1], we extend it by using quantum (or entropy) corrected new agegraphic dark energy in the Brans-Dicke cosmology. The correction terms are motivated from the loop quantum gravity which is one of the competitive theories of quantum gravity. Taking the non-flat background spacetime along with the conformal age of the universe as the length scale, we derive the dynamical equation of state of dark energy and the deceleration parameter. An important consequence of this study is the phantom divide scenario with entropy-corrected new agegraphic dark energy. Moreover, we assume a system of dark matter, radiation and dark energy, while the later interacts only with dark matter. We obtain some essential expressions related with dark energy dynamics. The cosmic coincidence problem is also resolved in our model.Comment: 16 pages, no figure, accepted for publication in Gen. Relativ. Gra

Effect of Somatic Cell Types and Culture Medium on in vitro Maturation, Fertilization and Early Development Capability of Buffalo Oocytes

This study was designed to evaluate the efficacy of different somatic cell types and media in supporting in vitro maturation (IVM), in vitro fertilization (IVF) and early embryonic development competence of buffalo follicular oocytes. Cumulus oocyte complexes were collected for maturation from follicles (>6mm) of buffalo ovaries collected at the local abattoir. Oocytes were co-cultured in tissue culture medium (TCM-199) with either granulosa cells, cumulus cells, or buffalo oviductal epithelial cells (BOEC) @ 3x106 cells/ml or in TCM-199 without helper cells (control) at 39°C and 5%CO2 in humidified air. Fresh semen was prepared in modified Ca++ free Tyrode medium. Fertilization was carried out in four types of media: i) Tyrode lactate albumin pyruvate (TALP), ii) TALP+BOEC, iii) modified Ca++ free Tyrode and iv) modified Ca++ free Tyrode+BOEC. Fertilized oocytes were cultured for early embryonic development in TCM-199 with and without BOEC. Higher maturation rates were observed in the granulosa (84.24%) and cumulus cells (83.44%) than BOEC co culture system (73.37%). Highest fertilization rate was obtained in modified Ca++ free Tyrode with BOEC co culture (70.42%), followed by modified Ca++ free Tyrode alone (63.77%), TALP with BOEC (36.92%) and TALP alone (10.94%). Development of early embryos (8-cell stage) improved in TCM-199 with BOEC co culture than TCM-199 alone. From the results of this study, it can be concluded that addition of somatic cells (granulosa cells, cumulus cells) results in higher maturation rates of buffalo follicular oocytes than BOEC co culture system, while fertilization rate improved in modified Ca++ free Tyrode with and without BOEC. Addition of BOEC to TCM-199 improved the developmental capacity of early embryo