On the relationship between the modifications to the Raychaudhuri equation and the canonical Hamiltonian structures

The problem of obtaining canonical Hamiltonian structures from the equations of motion, without any knowledge of the action, is studied in the context of the spatially flat Friedmann-Robertson-Walker models. Modifications to Raychaudhuri equation are implemented independently as quadratic and cubic terms of energy density without introducing additional degrees of freedom. Depending on their sign, modifications make gravity repulsive above a curvature scale for matter satisfying strong energy condition, or more attractive than in the classical theory. Canonical structure of the modified theories is determined demanding that the total Hamiltonian be a linear combination of gravity and matter Hamiltonians. In the quadratic repulsive case, the modified canonical phase space of gravity is a polymerized phase space with canonical momentum as inverse trigonometric function of Hubble rate; the canonical Hamiltonian can be identified with the effective Hamiltonian in loop quantum cosmology. The repulsive cubic modification results in a `generalized polymerized' canonical phase space. Both of the repulsive modifications are found to yield singularity avoidance. In contrast, the quadratic and cubic attractive modifications result in a canonical phase space in which canonical momentum is non-trigonometric and singularities persist. Our results hint on connections between repulsive/attractive nature of modifications to gravity arising from gravitational sector and polymerized/non-polymerized gravitational phase space.Comment: 22 pages with two new plots. Discussion on uniqueness added, and possible links with existing models expanded. Periodicity for 'generalized polymerized' theory and its comparison with standard polymerization discussed. References added. To appear in CQ

Scalar meson in dynamical and partially quenched two-flavor QCD: lattice results and chiral loops

This is an exploratory study of the lightest non-singlet scalar $q\bar q$ state on the lattice with two dynamical quarks. Domain Wall fermions are used for both sea and valence quarks on a 16^3*32 lattice with an inverse lattice spacing of 1.7 GeV. We extract the scalar meson mass 1.58(34) GeV from the exponential time-dependence of the dynamical correlators with $m_{val}=m_{sea}$ and N_f=2. Since this statistical error-bar from dynamical correlators is rather large, we analyze also the partially quenched lattice correlators with $m_{val}$ not equal $m_{sea}$. They are positive for $m_{val}>=m_{sea}$ and negative for $m_{val}<m_{sea}$. In order to understand this striking effect of partial quenching, we derive the scalar correlator within the Partially Quenched ChPT and find it describes lattice correlators well. The leading unphysical contribution in Partially Quenched ChPT comes from the exchange of the two pseudoscalar fields and is also positive for $m_{val}>=m_{sea}$ and negative for $m_{val}<m_{sea}$ at large t. After the subtraction of this unphysical contribution from the partially quenched lattice correlators, the correlators are positive and exponentially falling. The resulting scalar meson mass 1.51(19) GeV from the partially quenched correlators is consistent with the dynamical result and has appreciably smaller error-bar.Comment: 23 pages, 8 figure

Comparative study of Hemp and Jatropha oil blends used as an alternative fuel in diesel engine

Abstract: The methyl esters of vegetable oils, known as biodiesel are becoming increasingly popular because of their low environmental impact and potential as a green alternate fuel for diesel engines. Use of vegetable oils in conventional not adapted diesel engines leads to slightly inferior performance and higher smoke emissions due to their high viscosity. The performance of vegetable oils can be improved by modifying them through the transesterification process. In the present study, a comparison on the basis of the performance and emission characteristics of different blends of transesterified Hemp (B10 and B20)and Jatropha (B10 and B20) biodiesel was done on a 550 cm&sup3; single cylinder four stroke water cooled diesel engine and the results were compared to that of diesel. Results indicated that in comparison to pure diesel and Jatropha, B20 blend of Hemp biodiesel provides better thermal efficiency, lower specific fuel consumption, reduced CO and CO2 emissions but a considerable increase was found in NOx emission and smoke density was decreased with increase in biodiesel concentration i.e. at 20%.&nbsp;Keywords: Bio-diesel, hemp oil, Jatropha oil, transesterification, engine performance, exhaust emissions, Indi

COMBINATION OF LEPTIN ANALOG AND SALBUTAMOL: TREATMENT APPROACH FOR OBESITY-INDUCED ASTHMA

Objective: The objective of the study was to investigate the effect of leptin analog and salbutamol in obese asthmatic mice. Methods: Obese asthmatic condition was induced by administration of hypercaloric diet for 8 weeks followed by ovalbumin-aluminum hydroxide. The animals were treated with leptin analog (0.4 mg/kg, i.p. for 14 days) and salbutamol (2 mg/kg, PO for 14 days). Biochemical parameters such as serum leptin, ghrelin, and tumor necrosis factor-α and physical parameters such as tidal volume and airflow rate were estimated to confirm the state of asthma and obesity, respectively. Results: Elevated serum leptin and ghrelin were associated with leptin resistance in obese asthmatic mice. It was found that a significant increase in serum leptin level with animal treated with leptin analog and salbutamol when compared to animals treated with leptin analog alone. The result of respiratory parameters and serum parameters also improved with the combination of leptin analog and salbutamol. From our study, we found that salbutamol potentiates the effect of leptin analog in obese asthmatic condition. Conclusion: Leptin analog and salbutamol are an alternative treatment approach to treat the obese asthmatic condition

Anomalous Thermoelectric power of over-doped Bi2Sr2CaCu2O8 superconductor

Temperature dependence of thermoelectric power S(T) of three differently processed Bi2Sr2CaCu2O8 (Bi2212) samples, viz. as-processed melt quenched (Bi2212-MQ), 6000C N2-annealed (Bi2212-N2) and 6000C O2-annealed (Bi2212-O2) is reported here. All the samples possess single-phase character and their superconducting transition temperatures (TcR=0) are 85 K, 90 K and 72 K respectively for Bi2212-MQ, Bi2212-N2 and Bi2212-O2. While Bi2212-MQ and Bi2212-N2 samples are in near optimum doping regime, Bi2212-O2 is an over-doped sample. TcS=0 values obtained through S(T) data are also in line with those deduced from the temperature dependence of resistance and DC magnetization. Interestingly, S(T) behaviour of the optimally-doped Bi2212-MQ and Bi2212-N2 samples is seen to be positive in whole temperature range, it is found negative for the over-doped Bi2212-O2 sample above TcS=0. These results have been seen in the light of the recent band structure calculations and the ensuing split Fermi surface as determined by angle-resolved photoelectron spectroscopy (ARPES).Comment: 11 Pages Text + Figs: comments welcome ([email protected]

Effective and Efficient Algorithms for Concise Range Queries

With the advance of wireless communication technology, it is quite common for people to view maps or get related services from the handheld devices, such as mobile phones and PDAs. Range queries, as one of the most commonly used tools, are often posed by the users to retrieve needful information from a spatial database. However, due to the limits of communication bandwidth and hardware power of handheld devices, displaying all the results of a range query on a handheld device is neither communication efficient nor informative to the users. This is simply because that there are often too many results returned from a range query. In view of this problem, we present a novel idea that a concise representation of a specified size for the range query results, while incurring minimal information loss, shall be computed and returned to the user. Such a concise range query not only reduces communication costs, but also offers better usability to the users, providing an opportunity for interactive exploration. The usefulness of the concise range queries is confirmed by comparing it with other possible alternatives, such as sampling and clustering. Unfortunately, we prove that finding the optimal representation with minimum information loss is an NP-hard problem. Therefore, we propose several effective and nontrivial algorithms to find a good approximate result. Extensive experiments on real-world data have demonstrated the effectiveness and efficiency of the proposed techniques

Grand Unification of Quark and Lepton FCNCs

In the context of Supersymmetric Grand Unified theories with soft breaking terms arising at the Planck scale, it is generally possible to link flavor changing neutral current and CP violating processes occurring in the leptonic and hadronic sectors. We study the correlation between flavor changing squark and slepton mass insertions in models \`a la SU(5). We show that the constraints coming from lepton flavor violation exhibit a strong impact on CP-violating B decays.Comment: 4 pages, 1 figur

Use of Geotextiles in Low Volume Roads — A Case Study

The application of geotextiles has been well accepted as a construction material in Civil engineering works. However, in India, the utility of geotextiles is very limited to particular areas of application in Civil Engineering such as highways, railways and irrigation projects etc. On an experimental basis, these fabrics have been used as an intermediate layer between subgrade and subbase to serve as a separation and drainage layer in a road constructed on soft subgrade soil. The main objective of field trials was to study the need, relevance and the relative efficacy of the use of geotextiles as compared to the use of conventional techniques in the construction and maintenance of road pavements on soft subgrades. The surface characteristics of different test sections were evaluated in terms of riding quality, rut depth and transverse/longitudinal slope variance. The structural adequacy of different specifications were determined using Benklemen Beam deflection tests. Based on the detailed data analysis, it is concluded that the geosynthetics are an effective substitute for conventional blanket courses as a separator with the added benefit that they ensure more effective subsurface drainage of the pavement compared to conventional blanket courses