ENHANCEMENT OF SUPERCONDUCTIVITY IN LEAD (Pb) BY INTENSIFIED GRAVITATIONAL INTERACTION BETWEEN ELECTRON PAIRS

This work focuses on the theoretical investigation of the possible enhancement of superconductivity for the superconducting lead (Pb) by intensified gravitational interaction (IGI) between electron pairs. By applying the quantization theory of gravity (QTG), we obtained expressions for the enhanced superconducting transition temperature (), and superconducting energy gap (). By using the experimental, theoretical values and some plausible approximations of the parameters in the obtained expressions, the phase diagrams of superconducting energy gap versus temperature for lead at  and the enhanced superconducting energy gap versus temperature for lead at are plotted. By combining the two phase diagrams, we had shown the possible enhancement of the superconducting transition temperature from to and its superconducting energy gap fromto  for the superconducting lead

Coexistence of Superconductivity and Ferromagnetism in Superconducting ErRh4B4

This research work focuses on the theoretical investigation of the possible coexistence of superconductivity and ferromagnetism in ErRh4B4. By developing a model Hamiltonian for the given system and by using the double time temperature-dependent Green’s function formalism, we obtained expressions for superconducting transition temperature (TC,), magnetic ordering temperature (Tm), superconducting and magnetic ordering parameters (Δ) and (η) respectively. By using the experimental and theoretical values and by considering plausible approximations of the parameters in the obtained expressions, the phase diagrams of superconducting transition temperature versus magnetic ordering parameter and magnetic ordering temperature versus magnetic ordering parameter are plotted. Finally, by combining the two phase diagrams, we showed the possible coexistence of superconductivity and ferromagnetism in ErRh4B4.Keywords: Superconductivity, ferromagnetism, order parameter, conduction electrons, localized electrons, Green’s function

Theoretical analyses of superconductivity in iron based superconductor Ba1−xKxFe2As2

This paper focuses on the theoretical analysis of superconductivity in iron based superconductor Ba1−xKxFe2As2. After reviewing the current findings on this system, we suggest that phononexciton combined mechanism gives a right order of  superconducting transition temperature (TC) for Ba1−xKxFe2As2 . By developing a model Hamiltonian for the system under consideration, using double time  temperature dependent Green’s function formalism and a suitable decoupling approximation technique, we have analyzed theoretically the superconductivity of iron-based superconductor Ba1−xKxFe2As2. Furthermore, by using the  experimental and plausible theoretical values of the parameters in the obtained expressions, phase diagrams of superconducting transition temperature (TC) versus electron coupling constant (λe) and superconducting transition temperature (TC) versus superconducting gap parameter (Δhave been plotted. Our findings demonstrate that, as the electron coupling constant (λe) increases the superconducting transition temperature (TC) increases and vice versa and also as the temperature increases the superconducting order parameter decreases and vanishes at the transition temperature (TC) for Ba1−xKxFe2As2. Our findings are in a broad agreement with the experimental observations.Keywords: Iron based Superconductors, Green’s Function formalism,   Superconducting order parameter, Ba1−xKxFe2As2

Scandinavian Attitudes towards Immigrants. A Comparative Study of Denmark, Norway and Sweden

In the last few decades immigration from many parts of the world has transformed Scandinavian countries from once homogenous societies to multicultural countries. Immigrants and their off-springs constitute 10 to 15% of the populations in Denmark, Norway and Sweden. The arrival of immigrants has been varying from time to time depending on the prevailing economic and political situations. Similarly the reaction of host societies towards immigrants and their impact on the economy, culture and politics has been dependent on the particular socioeconomic and social psychological circumstances of individuals residing in these societies. Using data from the European Values Survey in 2008, this thesis explores the factors that determine attitudes towards immigrants. The results indicate that Scandinavian attitudes towards immigrants are driven more by concerns about identity and politics than economy. National identity, particularly, its ethnic expression is the most important predictor of attitudes towards immigrants. Following ethnic identity, it is politics, especially self-placement on the left-right spectrum of political views is that explains attitudes towards immigrants

Scandinavian Attitudes towards Immigrants. A Comparative Study of Denmark, Norway and Sweden

In the last few decades immigration from many parts of the world has transformed Scandinavian countries from once homogenous societies to multicultural countries. Immigrants and their off-springs constitute 10 to 15% of the populations in Denmark, Norway and Sweden. The arrival of immigrants has been varying from time to time depending on the prevailing economic and political situations. Similarly the reaction of host societies towards immigrants and their impact on the economy, culture and politics has been dependent on the particular socioeconomic and social psychological circumstances of individuals residing in these societies. Using data from the European Values Survey in 2008, this thesis explores the factors that determine attitudes towards immigrants. The results indicate that Scandinavian attitudes towards immigrants are driven more by concerns about identity and politics than economy. National identity, particularly, its ethnic expression is the most important predictor of attitudes towards immigrants. Following ethnic identity, it is politics, especially self-placement on the left-right spectrum of political views is that explains attitudes towards immigrants

Developing a zebrafish model of epidermolysis bullosa

Skin forms the physical boundary between internal and external environment being the first line of defense against insults. It is composed of variety of cells expressing specific molecules that maintain the normal structural integrity and function. One family of molecules includes keratins which are cytoskeletal complex proteins that form intermediate filaments in the epithelial cells. However, the entire organization and function of keratin networks can be disrupted because of single mutation in one of these molecules, leading to the inherited skin disease, epidermolysis bullosa simplex, an inherited skin disorder characterized by the formation of blisters. Zebrafish has not been extensively used to model human skin diseases to date. Hence, the main target of this work is establishing robust models of heritable skin diseases in zebrafish, focusing mostly on basal keratinocytes bullosa diseases to understand their molecular pathomechanism in vivo. Here we have generated transgenic lines overexpressing mutant forms of zebrafish Krtt1c19e and human KRT14 proteins, which are associated with generation of epidermolysis bullosa simplex in humans. Confocal analysis of immunostained zebrafish larvae expressing these mutant forms of KRT14 and Krtt1c19e showed subtle differences in keratin distribution in basal cells, but which produce keratin aggregates and dramatic alterations in keratin architecture upon heat and cold stress, suggesting that mutant keratins are affecting proper keratin dimerization process. We also found that there is cell adhesion disruption and keratinocytes detachment in the epidermolysis bullosa simplex zebrafish model via live imaging of basal XIII keratinocytes. In addition, using the CRISPR/Cas9 system, we generated col7a1 null zebrafish to establish a dystrophic epidermolysis bullosa zebrafish model. As of yet, no blistering has been observed under normal condition and proteomics analysis was carried out to check the status of the protein in the col7a1 double knockout fish. We found upregulation of three collagens; Col28a2a, Col6a2 and Col14a1b. Overall, this study provides new insights into understanding cellular and molecular defects in vivo and establishes a platform for testing human epidermolysis bullosa simplex patient genetic lesions and development of therapeutic screens.Doctor of Philosoph

Coexistence of spin density wave and superconductivity in BaFe 2−x Co x As 2

The relationship between the spin density wave (SDW) and superconductivity is a central topic in the research on the FeAs-based high TC superconductors. In this research work, the theoretical investigation of the coexistence of spin density wave and superconductivity in BaFe 2-x Co x As has been made. By developing a model Hamiltonian for the system and using quantum field theory Green function formalism, we have found mathematical expressions for superconducting transition temperature (Tc), spin density wave transition temperature (Tsdw), superconductiviting order parameter (Δsc) and spin density wave order parameter (Δsdw). The phase diagrams of superconducting transition temperature versus superconductiviting order parameter and spin density wave transition temperature versus spin density wave order parameter have been plotted. By combining the two phase diagrams, we have obtained a phase diagram which shows the possible coexistence of spin density wave and superconductivity in BaFe 2 2-x Co x As 2.La relación entre la onda de densidad de espín (SDW) y la superconductividad es un tema central en la investigación sobre los superconductores de alta TC basados en FeAs. En este trabajo se ha realizado la investigación teórica de la coexistencia de onda de densidad de espín y la superconductividad en BaFe2-xCoxAs2. Mediante el desarrollo de un modelo de Hamilton para el sistema y el uso de la teoría del campo cuántico en función formalismo de Green, hemos encontrado expresiones matemáticas para la temperatura de transición superconductora (Tc), para la temperatura de transición de la densidad de onda del espín (Tsdw), para el parámetro de orden de la superconductividad (Δsc) y el parámetro de densidad de onda del espín (Δsdw). Se elaboraron los diagramas de fase de la temperatura de transición superconductora contra el parámetro de orden de la superconductividad y la temperatura de transición de la densidad de espín contra el parámetro de orden de la densidad de onda del espín. Mediante la combinación de los dos diagramas de fase, hemos obtenido otro diagrama de fase que muestra la posible coexistencia de onda de densidad del espín y la superconductividad del BaFe2-xCoxAs2

Theoretical investigation of upper critical magnetic field (Hc2) of the heavy fermion superconductor CeRhIn

This research work focuses on the theoretical investigation of the upper critical magnetic field of superconductorCeRhIn5. By using the well known Ginzburg-Landau (GL) phenomenological equation, we found the direct relationship between the GL coherence length (ξGL) and penetration depth (λGL) with temperature. From the GL equations and the results obtained for the GL coherence length, the expression for the upper critical magnetic field (HC2) is obtained for the superconductorCeRhIn5. The result is plotted as a function of temperature. The phase diagram shows the linear dependence of upper critical magnetic field (HC2) with temperature (T). The current finding is in agreement with experimental observations.Este trabajo de investigación se centra en la investigación teórica del campo magnético crítico superior del superconductor CeRhIn5. Utilizando la conocida ecuación fenomenológica de Ginzburg-Landau (GL), encontramos la relación directa entre la longitud de coherencia GL (ξGL) y la profundidad de penetración (λGL) con la temperatura. A partir de las ecuaciones GL y los resultados obtenidos para la longitud de coherencia GL, se obtiene la expresión para el campo magnético crítico superior (HC2) para el superconductorCeRhIn5. El resultado se representa en función de la temperatura. El diagrama de fase muestra la dependencia lineal del campo magnético crítico superior (HC2) con la temperatura (T). El hallazgo actual está de acuerdo con las observaciones experimentales

Theoretical Study of Upper Critical Magnetic Field ( H

This research work focuses on the theoretical investigation of the upper critical magnetic field, HC2; Ginzburg-Landau coherence length, ξGL(T); and Ginzburg-Landau penetration depth, λGL(T), for the two-band iron based superconductors BaFe2(As1-xPx)2, NdO1-xFxFeAs, and LiFeAs. By employing the phenomenological Ginzburg-Landau (GL) equation for the two-band superconductors BaFe2(As1-xPx)2, NdO1-xFxFeAs, and LiFeAs, we obtained expressions for the upper critical magnetic field, HC2; GL coherence length, ξGL; and GL penetration depth, λGL, as a function of temperature and the angular dependency of upper critical magnetic field. By using the experimental values in the obtained expressions, phase diagrams of the upper critical magnetic field parallel, HC2∥c, and perpendicular, HC2⊥c, to the symmetry axis (c-direction) versus temperature are plotted. We also plotted the phase diagrams of the upper critical magnetic field, HC2 versus the angle θ. Similarly, the phase diagrams of the GL coherence length, ξGL, and GL penetration depth, λGL, parallel and perpendicular to the symmetry axis versus temperature are drawn for the superconductors mentioned above. Our findings are in agreement with experimental observations