Scalar-Tensor Theory of Gravity and Generalized Second Law of Thermodynamics on the Event Horizon

In blackhole physics, the second law of thermodynamics is generally valid whether the blackhole is a static or a non-static one. Considering the universe as a thermodynamical system the second law of blackhole dynamics extends to the non-negativity of the sum of the entropy of the matter and the horizon, known as generalized second law of thermodynamics(GSLT). Here, we have assumed the universe to be bounded by the event-horizon or filled with perfect fluid and holographic dark energy in two cases. Thus considering entropy to be an arbitrary function of the area of the event-horizon, we have tried to find the conditions and the restrictions over the scalar field and equation of state for the validity of the GSLT and both in quintessence-era and in phantom-era in scalar tensor theory.Comment: 8 page

Dynamical scaling and isotope effect in temporal evolution of mesoscopic structure during hydration of cement

The evolution of mesoscopic structure for cement-water mixtures turning into colloidal gels remains far from being understood. Recent neutron scattering investigations (Phys. Rev. Lett. 93, 255704 (2004); Phys. Rev. B. 72, 224208 (2005); Phys. Rev. B. 82, 064203 (2010)),, reveal the role of hydrogen bond in temporal evolution of the mesoscopic structure during hydration of cement which is the most consumed synthetic material. The present neutron scattering investigation on hydration of cement with a mixture of light and heavy water points to incomprehensibility of the temporal evolution of the mesoscopic structure in terms of earlier observations on hydration with pure light or heavy water. Unlike in the case of hydration with light water, disagreement has been observed with the hypothesis of dynamical scaling for hydration of cement with a mixture of the two types of water. The dynamics of evolution of the mesoscopic structure has been observed to be nonlinear in regard to the composition of hydration medium.Comment: 16 Pages, 5 Figure

Cytoplasmic genic male-sterility in pigeonpea and its utilization in hybrid breeding programme

For commercial exploitation of heterosis in any crop, it is to develop an economically viable mass pollen transfer mechanism. The natural out-crossing pigeonpea occurs primarily due to insect visitations. wide range of natural is reported to be due to a number of factors, and number and types of pOllinating vectors being the most important one. The discovery of stable male sterility systems, availability natural out-crossing and evidence of heterotic advantage have set a perlect breaking the persisting yield plateau in pigeon pea through hybrid breeding. In spite of six genic male sterility based pigeonpea hybrids at the national level this technology was not adopted by seed sector. The second breakthrough came with the development of cytoplasmic genic male sterile lines in pigeon pea. To broaden the genetic base of newly established cytoplasmic genic male sterility systems in pigeonpea, twelve agronomically superior and good combiner lines were selected. These were Pusa 33, lCPL 87, GT 100, SKNP 289, SKPN 290, BDN 2, SKNP 88-3, SKNP 9523, T 15-15, T 21, UPAS 120 and lCPL 84023. These genotypes were converted into CMS lines through simple backcross breeding method. To study the stability of fertility restoration, 41 experimental hybrids were evaluated at Kanpur, Akola, SK Nagar and Faizabad. It was observed that the hybrids developed at SK Nagar and expressed high pollen fertility at both SK and Faizabad. However, at Kanpur, a variation for pollen fertility was recorded while at hybrids were almost male with pollen fertility ranging from 0 to 35%. This data indicated a significant role of environment in the expression of fertility restorer genes. Therefore, an attempt should be made to breed high yielding hybrid specifically adapted to region rather than aiming for widely adapted hybrids

Cosmological entropy and generalized second law of thermodynamics in F(R,G)F(R,G) theory of gravity

We consider a spatially flat Friedmann-Lemaitre-Robertson-Walker space time and investigate the second law and the generalized second law of thermodynamics for apparent horizon in generalized modified Gauss Bonnet theory of gravity (whose action contains a general function of Gauss Bonnet invariant and the Ricci scalar: $F(R,G)$). By assuming that the apparent horizon is in thermal equilibrium with the matter inside it, conditions which must be satisfied by $F(R,G)$ are derived and elucidated through two examples: a quasi-de Sitter space-time and a universe with power law expansion.Comment: 10 pages, minor changes, typos corrected, accepted for publication in Europhysics Letter

The generalized second law of thermodynamics of the universe bounded by the event horizon and modified gravity theories

In this paper, we investigate the validity of the generalized second law of thermodynamics of the universe bounded by the event horizon. Here we consider homogeneous and isotropic model of the universe filled with perfect fluid in one case and in another case holographic model of the universe has been considered. In the third case the matter in the universe is taken in the form of non-interacting two fluid system as holographic dark energy and dust. Here we study the above cases in the Modified gravity, f(R) gravity.Comment: 9 page

Anisotropic Dark Energy and the Generalized Second Law of Thermodynamics

We consider a Bianchi type $I$ model in which anisotropic dark energy is interacting with dark matter and anisotropic radiation. With this scenario, we investigate the validity of the generalized second law of thermodynamics. It is concluded that the validity of this law depends on different parameters like shear, skewness and equation of state.Comment: 12 pages, accepted for publication in Phys. Scr. arXiv admin note: text overlap with arXiv:1008.0692 and arXiv:1106.241

Arsenic-induced skin lesions among Atacameño people in Northern Chile despite good nutrition and centuries of exposure.

It has been suggested that the indigenous Atacameño people in Northern Chile might be protected from the health effects of arsenic in drinking water because of many centuries of exposure. Here we report on the first intensive investigation of arsenic-induced skin lesions in this population. We selected 11 families (44 participants) from the village of Chiu Chiu, which is supplied with water containing between 750 and 800 microg/L inorganic arsenic. For comparison, 8 families (31 participants) were also selected from a village where the water contains approximately 10 microg/L inorganic arsenic. After being transported to the nearest city for blind assessment, participants were examined by four physicians with experience in studying arsenic-induced lesions. Four of the six men from the exposed village, who had been drinking the contaminated water for more than 20 years, were diagnosed with skin lesions due to arsenic, but none of the women had definite lesions. A 13-year-old girl had definite skin pigmentation changes due to arsenic, and a 19-year-old boy had both pigmentation changes and keratoses on the palms of his hands and the soles of his feet. Family interviews identified a wide range of fruits and vegetables consumed daily by the affected participants, as well as the weekly intake of red meat and chicken. However, the prevalence of skin lesions among men and children in the small population studied was similar to that reported with corresponding arsenic drinking water concentrations in both Taiwan and West Bengal, India--populations in which extensive malnutrition has been thought to increase susceptibility

On thermodynamics second law in the modified Gauss Bonnet gravity

The second law and the generalized second law of thermodynamics in cosmology in the framework of the modified Gauss-Bonnet theory of gravity are investigated. The conditions upon which these laws hold are derived and discussed.Comment: 9pages, typos corrected, references adde

Family correlations of arsenic methylation patterns in children and parents exposed to high concentrations of arsenic in drinking water.

We investigated the evidence of a familial contribution to urinary methylation patterns in families ingesting arsenic in drinking water. Arsenic methylation can be assessed by measuring urinary levels of inorganic arsenic (InAs) and its methylated metabolites, monomethylarsonate (MMA), and dimethylarsinate (DMA). Methylation activity is reflected in the ratios: InAs/methylated arsenic (InAs/metAs) and MMA/DMA. Eleven families from Chile were selected because of their long-term exposure to very high levels of arsenic in drinking water (735-762 microg/L). Each family consisted of a father, a mother, and two children. We measured urinary arsenic and its methylated metabolites for each participant (n = 44). The intraclass correlation coefficients showed that 13-52% of the variations in the methylation patterns were from being a member of a specific family. Family correlations were calculated for father-mother, parent-child, and sibling-sibling pairs. Methylation patterns correlated strongly between siblings [r = 0.78 for InAs/metAs, 95% confidence interval (CI), 0.34-0.94; r = 0.82 for MMA/DMA, 95%CI, 0.43-0.95] compared to lower correlations in father-mother pairs (r = 0.18, r = -0.01, respectively), after adjustment for total urinary arsenic, age, and sex. Family correlations were not notably altered when adjustments were made for specific blood micronutrients (methionine, homocysteine, folate, vitamin B6, selenium, and vitamin B12 potentially related to methylation. We also report on a family pedigree with high prevalence of arsenic-induced effects. Participants from this family had low InAs/metAs values, which is consistent with increased toxicity of trivalent methylated arsenic species. Despite our small sample size, we observed that methylation patterns aggregate in families and are correlated in siblings, providing evidence of a genetic basis for the variation in arsenic methylation. Larger studies with more extensive pedigrees will need to be conducted to confirm these findings

Phase-field modeling of microstructural pattern formation during directional solidification of peritectic alloys without morphological instability

During the directional solidification of peritectic alloys, two stable solid phases (parent and peritectic) grow competitively into a metastable liquid phase of larger impurity content than either solid phase. When the parent or both solid phases are morphologically unstable, i.e., for a small temperature gradient/growth rate ratio ($G/v_p$), one solid phase usually outgrows and covers the other phase, leading to a cellular-dendritic array structure closely analogous to the one formed during monophase solidification of a dilute binary alloy. In contrast, when $G/v_p$ is large enough for both phases to be morphologically stable, the formation of the microstructurebecomes controlled by a subtle interplay between the nucleation and growth of the two solid phases. The structures that have been observed in this regime (in small samples where convection effect are suppressed) include alternate layers (bands) of the parent and peritectic phases perpendicular to the growth direction, which are formed by alternate nucleation and lateral spreading of one phase onto the other as proposed in a recent model [R. Trivedi, Metall. Mater. Trans. A 26, 1 (1995)], as well as partially filled bands (islands), where the peritectic phase does not fully cover the parent phase which grows continuously. We develop a phase-field model of peritectic solidification that incorporates nucleation processes in order to explore the formation of these structures. Simulations of this model shed light on the morphology transition from islands to bands, the dynamics of spreading of the peritectic phase on the parent phase following nucleation, which turns out to be characterized by a remarkably constant acceleration, and the types of growth morphology that one might expect to observe in large samples under purely diffusive growth conditions.Comment: Final version, minor revisions, 16 pages, 14 EPS figures, RevTe