142 research outputs found

    The Holography Hypothesis and Pre-Big Bang Cosmology

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    The consequences of holography hypothesis are investigated for the Pre-big-bang string cosmological models. The evolution equations are obtained from the tree level string effective action. It is shown that S/AS/A is bounded by a constant in each case, SS being the entropy within the volume bounded by the horizon of area AA.Comment: 11 pages, revtex, 1 eps fil

    Changes in sediment texture by turtle mass nesting at Rushikulya rookery

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    280-28

    A dual-pathway model of knowledge exchange: linking human and psychosocial capital with prosocial knowledge effectiveness

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    Purpose: This study aims to examine a dual-pathway model that recognizes two distinct (formal and informal) but complementary mechanisms of knowledge exchanges – knowledge sharing and knowledge helping. It also investigates how team members use their limited human and psychosocial capital for prosocial knowledge effectiveness. Design/methodology/approach: A survey-based approach was used to examine the hypotheses of the study. A moderated-mediation model was proposed and tested using bootstrap approach. Findings: Knowledge sharing and knowledge helping were found to be the significant links through which human capital (capability) and psychosocial capital (motivation and efficacy) significantly predict prosocial knowledge effectiveness. Post hoc analysis suggests that human capital through knowledge sharing influences team learning, whereas the psychosocial capital through knowledge helping influences team leadership. Originality/value: The present study found two distinct but complementary and yet necessary mechanisms of knowledge exchanges to be linked as the important outlay for the human and psychosocial capital to be effective in the prosocial knowledge behaviours

    Five Dimensional Cosmological Models in General Relativity

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    A Five dimensional Kaluza-Klein space-time is considered in the presence of a perfect fluid source with variable G and Λ\Lambda. An expanding universe is found by using a relation between the metric potential and an equation of state. The gravitational constant is found to decrease with time as Gt(1ω)G \sim t^{-(1-\omega)} whereas the variation for the cosmological constant follows as Λt2\Lambda \sim t^{-2}, Λ(R˙/R)2\Lambda \sim (\dot R/R)^2 and ΛR¨/R\Lambda \sim \ddot R/R where ω\omega is the equation of state parameter and RR is the scale factor.Comment: 13 pages, 4 figures, accepted in Int. J. Theor. Phy

    Mental health issues in pregnant women in Nepal

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    Mental health of pregnant women and new mothers is a growing area of concern in both low- and high-income countries. This editorial highlights some of the key mental issues faced by women in rural Nepal and outlines an intervention based on training community health care workers by experienced UK volunteers

    Some anisotropic universes in the presence of imperfect fluid coupling with spatial curvature

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    We consider Bianchi VI spacetime, which also can be reduced to Bianchi types VI0-V-III-I. We initially consider the most general form of the energy-momentum tensor which yields anisotropic stress and heat flow. We then derive an energy-momentum tensor that couples with the spatial curvature in a way so as to cancel out the terms that arise due to the spatial curvature in the evolution equations of the Einstein field equations. We obtain exact solutions for the universes indefinetly expanding with constant mean deceleration parameter. The solutions are beriefly discussed for each Bianchi type. The dynamics of the models and fluid are examined briefly, and the models that can approach to isotropy are determined. We conclude that even if the observed universe is almost isotropic, this does not necessarily imply the isotropy of the fluid (e.g., dark energy) affecting the evolution of the universe within the context of general relativity.Comment: 17 pages, no figures; to appear in International Journal of Theoretical Physics; in this version (which is more concise) an equation added, some references updated and adde

    Statefinder Parameters for Different Dark Energy Models with Variable G Correction in Kaluza-Klein Cosmology

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    In this work, we have calculated the deceleration parameter, statefinder parameters and EoS parameters for different dark energy models with variable GG correction in homogeneous, isotropic and non-flat universe for Kaluza-Klein Cosmology. The statefinder parameters have been obtained in terms of some observable parameters like dimensionless density parameter, EoS parameter and Hubble parameter for holographic dark energy, new agegraphic dark energy and generalized Chaplygin gas models.Comment: 9 pages, no figure, accepted for publication in IJTP. arXiv admin note: text overlap with arXiv:1104.2366 by other author

    Modelling and Prediction of Soil Organic Carbon using Digital Soil Mapping in the Thar Desert Region of India

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    Not AvailableIn the present study, the distribution of soil organic carbon (SOC) was investigated using digital soil mapping for an area of ~29 lakhs ha in Bikaner district, Rajasthan, India. To achieve this goal, 187 soil profiles were used for SOC estimation by Quantile regression forest (QRF) model technique. Landsat data, terrain attributes and bioclimatic variables were used as environmental variables. 10-fold cross-validation was used to evaluate model. Equal-area quadratic splines were fitted to soil profile datasets to estimate SOC at six standard soil depths (0-5, 5-15, 15-30, 30-60, 60-100 and 100-200 cm). Results showed that the mean SOC concentration was very low with values varied from 1.18 to 1.53 g kg-1 in different depths. While predicting SOC at different depths, the model was able to capture low variability (R2 = 1–7%). Overall, the Lin’s concordance correlation coefficient (CCC) values ranged from 0.01 to 0.18, indicating poor agreement between the predicted and observed values. Root mean square error (RMSE) and mean error (ME) were 0.97 and 0.16, respectively. The values of prediction interval coverage probability (PICP) recorded 87.2–89.7% for SOC contents at different depths. The most important variables for predicting SOC concentration variations were the annual range of temperature, latitude, Landsat 8 bands 2, 5 and 6. Temperature-related variables and remote sensed data products are important for predicting SOC concentrations in arid regions. We anticipate that this digital information of SOC will be useful for frequent monitoring and assessment of carbon cycle in arid regions.Not Availabl
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