The Time-Asymmetry and the Entropy Gap

The universe time-asymmetry is essentially produced by its low-entropy unstable initial state. Using quanlitative arguments, Paul Davies has demonstrated that the universe expansion may diminish the entropy gap, therefore explaining its low-entropy state, with respect to the maximal possible entropy at any time. This idea is implemented in a qualitative way\thinspace in a simple homogeneous model. Some rough coincidence with observational data are foundComment: 5 page

Entropy gap and time asymmetry II

In this letter the paper [R. Aquilano, M. Castagnino, Mod. Phys. Lett A,11, 755 (1996)] is improved by considering that the main source of entropy production are the stars photospheres

On Microgravity and Biological Process

Certain biological processes could be directly related to physics, such as telomere shortening and the activation of the telomerase enzyme. Telomere shortening is a well-known process that sets the pace of life in every living being. On the other hand, the reason behind telomere lengthening in some cases is not as well understood. We only know that it is directly linked to the activation of this enzyme. We put forth that time asymmetry is important to understand the cellular world, and microgravity and its variations could partially explain thisphenomenon.Fil: Aquilano, Roberto Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentin

On microgravity and its effects at the molecular level

There are biological processes that could be directly related to physics and the shortening of telomeres is one of them. This fact is something well known and acts like a clock in the life of each living being, but the reason why they are extended in some cases is something not so understood, it is only known that it is directly connected with the activation of telomerase, but it does not know, in some cases, the exact reasons that produces it. I propose that the asymmetry of time is important to know the cellular world, and could even be related to the cause of telomerase activation and the consequent lengthening of telomeres, and microgravity could be part of the explanation.Fil: Aquilano, Roberto Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentin

Microgravity and Telomeres

Variations in telomeres, and especially their shortening, is a well-known process that marks the rhythm of life in all living things, but the reason behind telomere lengthening in some cases is not so well understood. We only know that it isdirectly related to the activation of an enzyme called telomerase. Variations in microgravity could partially explain this phenomenon, and be part of the cause of its activation.Fil: Aquilano, Roberto Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentin

Gravity and Telomeres

Telomere shortening is a well-known process that is proposed to influence the pace of aging in every living being. On the other hand, telomere lengthening seems to be restricted to pluripotent cells and adult stem cell population, and it is mainly mediated by the enzyme telomerase. However, how is telomerase activation regulated in these compartments is largely unknown. Telomerase is also aberrantly upregulated in the vast majority of cancer cell where it allows for indefinite cell division. In previous papers, it has been put forth that time asymmetry is important to understand the cellular world, especially stem cells and cancer. This process could also be the cause of the telomerase activation and the corresponding telomere lengthening, but this stress mechanism described in the aforementioned articles could be extended to changes produced by the effects of gravity and the lack of gravity (weightlessness). This paper intends to expand on those previous papers.Fil: Aquilano, Roberto Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentin

Dynamics of a thin spherically symmetric radiating shells and collapsed astronomical objects

In ref. [1] it studied the dynamics of a thin dust radiating shell, endowed with spherical symmetry moving in the gravitational field of a central body. We used the General Relativity Theory; in our formalism the shell is a three-dimensional (two space like dimensions, one time like dimension) singular hypersurface [1, 2], with a Schwarzschild metric inside and Vaidya [3] metric outside. We used the model to study the detection of relativistic effects in novae and supernovae, and reach to the conclusion that, using these astronomical objects General Relativity effect will be very difficult to detect. In ref. [3] Hamity and Spinosa considering also a Vaidya metric in the interior of the shell, used this new model to study planetary nebula. In the present work we have used this last model to study different astronomical object: X-ray bursters, and Gamma-ray bursters.Asociación Argentina de Astronomí