Energy conditions for Bianchi type I universe in f(G) gravity

In this paper, we discuss energy conditions in modified Gauss-Bonnet gravity for locally rotationally symmetric Bianchi type I universe model with perfect fluid. The matter contents are constructed to discuss the energy conditions bounds. We take two specific f(G) models along with present day values of Hubble, deceleration, jerk and snap parameters. It is found that weak and null energy conditions are satisfied while strong energy conditions are violated for both models which represents the accelerated expansion of the universe.     

Re‐examining green revolution diffusion and factor/input markets in Bangladesh after market liberalization

This paper re‐examines the effect of green revolution (GR) diffusion on factor/inputs demand in Bangladesh using an empirical model that allows for simultaneous determination of factors influencing adoption of GR technology at the current mature stage, as well as access to irrigation. Results reveal some alignments with conventional wisdom as well as few surprises. For example, while an increased demand for major inputs is expected, an increased demand for organic manure is an unexpected positive outcome. The GR adoption rate is significantly higher in villages with access to irrigation and fertile soils and, surprisingly, in infrastructurally underdeveloped villages. Together with other expected findings of GR technology uptake with higher cereal prices and irrigation use encouraged by access to credit, tenurial status and fertile soils, our findings suggest that investment in irrigation and soil conservation, as well as implementing measures to improve cereal prices and provide agricultural credit, could boost GR technology adoption.     

Energy budget during fold tightening of a multilayer fold

The Canyon Range syncline, Central Utah, is composed of an alternating sequence of competent quartzite and incompetent argillite layers and is used here as a natural case study of multilayer folding processes. Geometric details of this fold are evaluated in terms of energy consumption in order to determine which kinematic components of folding are dominant at various stages of fold tightening. In addition, this paper attempts to evaluate what mechanism(s) (e.g. kink folding, fracture formation and sliding along surfaces) are involved in each kinematic component.In general, the patterns preserved in the Canyon Range syncline are comparable to multilayer folding models. In more detail, the following is concluded from this case study. (1) The competent and incompetent members deformed primarily by cataclastic flow and consumed approximately equal amounts of energy. (2) The roles of original competent and incompetent layers reversed during folding. (3) As the syncline tightened, less energy was consumed with increasing hinge fractions. (4) The least amount of energy was consumed with 40° limb dips (i.e., 100° interlimb angle). (5) With an open fold geometry (interlimb angle ≥140°), the hinge region consumed 70% of the fold's total energy. (6) Once the fold reached an interlimb angle of 60°, the limbs consume close to 70% of the total energy. (7) When the fold reached an interlimb angle of ≤60°, the incompetent layer(s) consumed 90% of the fold's energy.     

Folding by cataclastic flow: evolution of controlling factors during deformation

Folding at upper crustal levels occurs by bending of beds and flexural slip between beds. As a fold's interlimb angle decreases, changes in bed thickness and limb rotation are accommodated by various mechanisms, depending on deformation conditions. In the elastico-frictional (EF) regime, cataclastic flow may be the dominant mechanism for fold tightening. The Canyon Range (CR) syncline, located in the Sevier belt of central Utah, shows this type of deformation. The fold involves three thick quartzite units, with slight lithological variations between them. Fold tightening took place in the EF regime (<2 km overburden) by cataclastic flow, involving collective movement on a distributed network of fractures and deformation zones (DZs) from the micro- to the outcrop-scale. In detail, the degree of cataclastic deformation varies significantly across the fold due to minor variations in initial bedding thickness, grain size, matrix composition, etc. A cooperative relationship exists across different scales, and the fracture networks result in a fracture shape fabric that is relatively homogeneous at the outcrop-scale.The initial outcrop scale fracture/DZ network geometry is a product of the growth and linking of micro-scale cataclasite zones, which in turn is controlled by primary lithological variations. Once a fracture network forms, the material behavior of the fractured rock is unlike that of the original rock, with sliding of fracture-bound blocks accomplishing ‘block-controlled’ cataclastic flow. Thus, initial lithological variations at the micro-scale largely control the final deformation behavior at the largest scale. During progressive fold tightening, additional factors regulate cataclastic flow, such as fracture/DZ reactivation or healing, during folding. Although initial lithological variations in different units may produce unique network geometries, each unit's behavior may also depend upon the behavior of adjacent units. In the CR syncline, during the initial stages of cataclastic flow, the inherent nature of each quartzite unit results in unit-specific fracture network geometries. As deformation progresses, unit-specific networks begin to interact with those in surrounding units, resulting in feedback mechanisms regulating the later stages of network development. Thus, the nature of cataclastic flow changes dramatically from the initial to the final stages of folding.