Relationship between Body Image, Self-Esteem and Academic Behavior of Adolescent Girls in Karachi, Pakistan

Objective: The objective of the study is to explore the relationship between body image, self-esteem and academic behavior amongst adolescent girls living in Karachi, Pakistan and simultaneously explore the mediating role of self-esteem in the relationship of the other two variables. Methods: It was a cross-sectional study design with a sample size of 400 adolescent girls belonging to a selected community of Karachi, Pakistan. Pre-validated tools, Body Shape Questionnaire, Rosenberg Self-Esteem Scale and Academic Behavior Scale were used for data collection of the study. The data was then analyzed using SPSS 17. Results: The results proved significant associations between all three variables with p<0.05. Moreover, a partially mediating role of self-esteem was noticed to be causing 74.8% variation in the relationship between body image and academic behavior. Conclusion: As per the study findings, body image, self-esteem and academic behavior of adolescent girls residing in Karachi, Pakistan are associated with each other. It was also concluded that higher body image dissatisfaction may lead to poor self-esteem which in turn negatively impacts the positive academic behavior of the girls. Hence, representing a mediating role of self-esteem in the relationship.  Overall, parents, educators, academic professionals, counselors and healthcare professionals can benefit from the study findings to positively play their parts in improving the lives of adolescents around them.       

Gravitational Collapse in F R, T Modified Theory of Gravity

In this thesis, we investigate gravitational collapse in f(R, T) modified theory of gravity. We focus on the study of gravitational collapse of spherically symmetric and FriedmannRobertsonWalker(FRW) metrics for both dust and perfect fluid cases. We also explore the gravitational collapse of 5D spherically symmetric spacetime in f(R, T) gravity and extend this work to N-dimensional spherically symmetric spacetimes. Furthermore, we explore the effect of electromagnetic fields on the gravitational collapse in f(R, T) modified theory of gravity. Firstly, we discuss the gravitational collapse of spherically symmetric spacetime for both dust and perfect fluid cases in f(R, T) gravity. For this purpose, we consider the spherically symmetric spacetime as the interior region and Schwarzschild metric as the exterior region. The junction conditions between the exterior and interior regions are found by matching the exterior and interior regions. The field equations are solved by taking the assumptions that the Ricci scalar as well as the trace of energy-momentum tensor are constant, for a particular f(R, T) = R + 2f(T) model. We calculate the gravitational mass of the collapsing system. Also, we discuss the apparent horizons and their time formation for different possible cases. It is shown that the term f(R0, T0) behaves as a source of repulsive force and consequently it slows the collapse of matter. We then discuss gravitational collapse in the context of f(R, T) gravity by taking FRW metric in the interior and schwarzschild background in the exterior regions of the star. We solve the field equations by taking the assumption of constant curvature and constant trace of energy-momentum tensor. We found that the terms 2λρ0−f(R0, T0) and f(R0, T0)+2λ(p0−ρ0) behave as cosmological constant for both dust and perfect fluid cases. Next, we discuss spherically symmetric perfect fluid collapse in the frame work of f(R, T ) modified theories of gravity using a five dimensional background. For this reason we consider the five dimensional spherically symmetric metric as the interior region and a five dimensional Schwarzschild metric as an exterior region. The junction conditions between the exterior and interior regions are discussed. By taking above mentioned model, the corresponding field equations are evaluated for both marginally bound L(r) = 1 and non-marginally bound L(r) 6= 1 cases. We find the apparent horizons and their time formation for different possible cases. It has been concluded that the term involving λ plays double role: it speeds up the collapse in region where ρ0 < 4p0; and it slows down the collapsing of matter when ρ0 > 4p0. Furthermore, we extend this work to the N-dimensional case and find that the collapse process becomes faster in the region ρ0 < (n + 1)p0 and slower in the region ρ0 > (n + 1)p0. Furthermore, it is noted that our results reduce to previously published results [80] found in GR for λ = 0. Finally, we analyze the effect of electromagnetic field on the gravitational collapse in f(R, T ) modified theories of gravity by taking spherically symmetric metric in the interior region and Reissner-Nordstrom ¨ metric in the exterior region. We discuss the issue of apparent horizons. We conclude that the end state of a star, in the presence of electromagnetic fields in the f(R, T ) gravity framework, is a black hole. It is shown that the collapse is slower in the region ρc < 3pc and faster in the region ρc > 3pc. Moreover, for λ = 0, our results correspond to those of GR found previously[120].