Behavior of Time-varying Constants in Relativity

In this paper, we consider Bianchi type III and Kantowski-Sachs spacetimes and discuss the behavior of time-varying constants $G$ and $\Lambda$ by using two symmetric techniques, namely, kinematic self-similarity and matter collineation. In the kinematic self-similarity technique, we investigate the behavior of the first and the second kinds. In the matter collineation technique, we consider usual, modified, and completely modified matter collineation equations while studying the behavior of these constants. Further, we reduce the results for dust, radiation, and stiff fluids. We find that $\Lambda$ is a decreasing time function while $G$ is an increasing time function. This corresponds to the earlier results available in the literature for other spacetimes. Further, we find that the deceleration parameter attains a negative value, which shows that the expansion of the universe is accelerating.Comment: 24 pages, accepted for publication in J. Korean Physical Societ

Gravitational Wave Polarization Modes in f(R)f(R) Theories

Many studies have been carried out in the literature to evaluate the number of polarization modes of gravitational waves in modified theories, in particular in $f(R)$ theories. In the latter ones, besides the usual two transverse-traceless tensor modes present in general relativity, there are two additional scalar ones: a massive longitudinal mode and a massless transverse mode (the so-called breathing mode). This last mode has often been overlooked in the literature, due to the assumption that the application of the Lorenz gauge implies transverse-traceless wave solutions. We however show that this is in general not possible and, in particular, that the traceless condition cannot be imposed due to the fact that we no longer have a Minkowski background metric. Our findings are in agreement with the results found using the Newman-Penrose formalism, and thus clarify the inconsistencies found so far in the literature.Comment: 7 pages; accepted for publication in Phys. Rev.

Hubungan Tingkat Keberdayaan dengan Tingkat Kemandirian Anggota Kelompoktani Program Sistem Pertanian Terpadu (Spt) PT. Rapp di Kabupaten Siak

The purpose of this research are: 1) Assessing the level of empowerment program members of farmer groups Integrated Farming Systems PT. RAPP in Siak, 2) Assess the degree of independence of members of farmers program Integrated Farming Systems PT. RAPP in Siak, 3) Knowing the empowerment level relationship with the level of independence of farmers program Integrated Farming Systems PT. RAPP in Siak. This study was conducted in Siak district, which includes three sub-districts right kerinci, District and Sub-District Dayun River Apit starting from September 2015 to January 2017. The determination of sampling determined by purposive sampling with the consideration that the farmer who made the respondent is a member of the built members of farmer groups PT. RAPP program received Integrated Agricultural Systems, members of farmer groups most active members, assistance programs Integrated Farming System representing all farmer groups. The number of respondents as many as 30 people. The analysis using Likert scale and Rank Spearman correlation analysis. The results of this study show that: 1) The level of empowerment members of farmer groups in the program Integrated Farming Systems Siak Regency included in the category of Most Powerful. 2) The level of independence of members of farmer groups in Siak program Integrated Farming Systems included in the High category. 3) Relationship level of empowerment to the level of independence of members of farmers Integrated Farming Systems program showed a positive correlation (Unidirectional). This suggests that when the members of the degree of independence helpless farmer group members is also high

Synthesis, Characterization and Biological Properties of Tridentate NNO, NNS and NNN Donor Thiazole-Derived Furanyl, Thiophenyl and Pyrrolyl Schiff Bases and Their Co(II), Cu(II), Ni(II) and Zn(II) Metal Chelates

2-Aminothiazole undergoes condensation reactions with furane-, thiophene- and pyrrole-2-carboxylaldehyde to give tridentate NNO, NNS and NNN Schiff bases respectively. These tridentate Schiff bases formed complexes of the type [M (L)2]X2 where [M=Co(II), Cu(II), Ni(II) or Zn(II), L=N-(2-furanylmethylene)-2-aminothiazole (L1), N-(2-thiophenylmethylene)-2-aminothiazole (L2, N-(2-pyrrolylmethylene)-2-aminothiazole (L3) and X=Cl. The structures of these Schiff bases and of their complexes have been determined on the basis of their physical, analytical and spectral data. The screening results of these compounds indicated them to possess excellent antibacterial activity against tested pathogenic bacterial organisms e.g., Escherichia coli, Staphylococcus aureous and Pseudomonas aeruginosa. However, in comparison, their metal chelates have been shown to possess more antibacterial activity than the uncomplexed Schiff bases