Wormhole solutions with a polynomial equation-of-state and minimal violation of the null energy condition

This paper discusses wormholes supported by general equation-of-state , resulting in a significant combination of the linear equation-of-state and some other models. Wormhole with a quadratic equation-of-state is studied as a particular example. It is shown that the violation of null energy condition is restricted to some regions in the vicinity of the throat. The combination of barotropic and polytropic equation-of-state has been studied. We consider fluid near the wormhole throat in an exotic regime which at some $r=r_{1}$, the exotic regime is connected to a distribution of asymptotically dark energy regime with $-1<\omega<-1/3$. We have presented wormhole solutions with small amount of exotic matter. We have shown that using different forms of equation-of-state has a considerable effect on the minimizing violation of the null energy condition. The effect of many parameters such as redshift as detected by a distant observer and energy density at the throat on the $r_1$ is investigated. The solutions are asymptotically flat and compatible with presently available observational data at the large cosmic scale.Comment: 12 pages, 13 figure

Quantum scalar field in quantum gravity: the propagator and Lorentz invariance in the spherically symmetric case

We recently studied gravity coupled to a scalar field in spherical symmetry using loop quantum gravity techniques. Since there are local degrees of freedom one faces the "problem of dynamics". We attack it using the "uniform discretization technique". We find the quantum state that minimizes the value of the master constraint for the case of weak fields and curvatures. The state has the form of a direct product of Gaussians for the gravitational variables times a modified Fock state for the scalar field. In this paper we do three things. First, we verify that the previous state also yields a small value of the master constraint when one polymerizes the scalar field in addition to the gravitational variables. We then study the propagators for the polymerized scalar field in flat space-time using the previously considered ground state in the low energy limit. We discuss the issue of the Lorentz invariance of the whole approach. We note that if one uses real clocks to describe the system, Lorentz invariance violations are small. We discuss the implications of these results in the light of Horava's Gravity at the Lifshitz point and of the argument about potential large Lorentz violations in interacting field theories of Collins et. al.Comment: Dedicated to Josh Goldberg, to appear in special issue of Gen. Rel. Grav., 14 pages RevTex. We expanded the section on Lorentz invarianc

New variables for 1+1 dimensional gravity

We show that the canonical formulation of a generic action for 1+1-dimensional models of gravity coupled to matter admits a description in terms of Ashtekar-type variables. This includes the CGHS model and spherically symmetric reductions of 3+1 gravity as particular cases. This opens the possibility of discussing models of black hole evaporation using loop representation techniques and verifying which paradigm emerges for the possible elimination of the black hole singularity and the issue of information loss.Comment: 8 pages, no figures, added references, corrected some misleading statement

THE TEN MONTH INVESTIGATION AND EDUCATION FOR EFFECTING OF CORRECTIVE FEEDBACK FOR THE SECOND LANGUAGE (L2) PRAGMATICS IN IRAN

Feedback é qualquer informação fornecida sobre a precisão e adequação de uma resposta. Para determinar o efeito do feedback na língua nativa e persa na leitura e escrita em estudantes bilíngues (curdos-farsos), 45 alunos do ensino fundamental foram selecionados pelo método de amostragem por cluster no Irã. Neste artigo, os alunos foram divididos em três grupos distintos: o primeiro grupo experimental recebendo feedback em seu idioma nativo, o segundo grupo experimental recebendo feedback em idioma nativo e o grupo controle sem feedback. Um teste de desempenho acadêmico projetado pelo pesquisador foi usado para coletar os dados. Os resultados da análise de covariância mostraram que o fornecimento de feedback na língua nativa teve um efeito significativo na leitura e escrita de estudantes bilíngues e houve uma diferença significativa entre o primeiro grupo experimental (recebendo feedback na língua nativa) e o grupo controle (que não apresentou receber feedback). . Mas não houve diferença significativa entre o segundo grupo experimental (feedback recebido em farsi) e o grupo controle. Essas descobertas mostraram que o fornecimento de feedback na língua farsi não influenciou significativamente o progresso da leitura e escrita dos alunos bilíngues. Com base nos resultados do presente estudo, pode-se concluir que fornecer feedback em idioma nativo para estudantes bilíngues pode ser eficaz para melhorar seu desempenho.La retroalimentación es cualquier información proporcionada sobre la precisión y la idoneidad de una respuesta. Para determinar el efecto de la retroalimentación en lengua nativa y persa en la lectura y escritura en estudiantes bilingües (kurdos-farsi), se seleccionaron 45 estudiantes de primaria mediante el método de muestreo por conglomerados en Irán. En este documento, los estudiantes se dividieron en tres grupos distintos: el primer grupo experimental que recibió comentarios en su idioma nativo, el segundo grupo experimental que recibió comentarios en idioma nativo y el grupo de control que no recibió comentarios. Se utilizó una prueba de rendimiento académico diseñada por un investigador para recopilar los datos. Los resultados del análisis de covarianza mostraron que proporcionar retroalimentación en el idioma nativo tuvo un efecto significativo en la lectura y escritura de los estudiantes bilingües y hubo una diferencia significativa entre el primer grupo experimental (que recibió retroalimentación en el idioma nativo) y el grupo de control (que no recibir comentarios). . Pero no hubo diferencias significativas entre el segundo grupo experimental (recibió retroalimentación en farsi) y el grupo de control. Estos hallazgos mostraron que proporcionar comentarios en idioma farsi no influyó significativamente en el progreso de lectura y escritura de los estudiantes bilingües. Con base en los hallazgos del presente estudio, se puede concluir que proporcionar comentarios sobre el idioma nativo a los estudiantes bilingües puede ser efectivo para mejorar su rendimiento.Feedback is any information provided about the accuracy and appropriateness of a response. To determine the effect of feedback in native and Persian language on reading and writing in bilingual (Kurdish-Farsi) students, 45 elementary school students were selected by cluster sampling method in Iran. In this paper, Students were divided into three distinct groups: the first experimental group receiving feedback in their native language, the second experimental group receiving feedback in native language, and the control group receiving no feedback. A researcher-designed test of academic achievement was used to collect the data. The results of covariance analysis showed that providing feedback in native language had a significant effect on the reading and writing of bilingual students and there was a significant difference between the first experimental group (receiving feedback in native language) and the control group (which did not receive feedback). . But there was no significant difference between the second experimental group (received feedback in Farsi) and the control group. These findings showed that providing feedback in Farsi language did not significantly influence bilingual students' reading and writing progress. Based on the findings of the present study, it can be concluded that providing native language feedback to bilingual students can be effective in improving their performance