998 research outputs found
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
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
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
Experimental value of the specific surface energy of the cleavage 10.4 calcite rhombohedron in the presence of its saturated aqueous solution
In this study, we describe a method to obtain experimental values of the surface energy of calcite. A zenithal imaging device was used to acquire pictures of droplets of CaCO3 saturated aqueous solution on the surface of a calcite crystal sample. Pictures were used to measure the contact angle between the droplets and the {10.4} calcite surfaces. The method is discussed along with its geometrical ground, as well as the theoretical foundation of the contact angle calculation. A comparison is made with the literature data; a good agreement is found between our experimental values and those obtained from the more recent ab initio calculations
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
Estudios patológicos y propuestas de recuperación de obras públicas de la provincia de Buenos Aires, Argentina
La proximidad del Bicentenario contribuye a movilizar la conciencia histórica de la Nación y de sus estados provinciales. En vísperas de este trascendental acontecimiento, las miradas sobre nuestro pasado adquieren renovado interés y potencian la profunda resignificación que asume un momento singular en la historia de los argentinos, con proyección presente y futura.
En función de ello el Ministerio de Infraestructura ha desarrollado un programa de intervención en edificios patrimoniales que contribuya a acrecentar la valoración de la obra pública provincial, revitalizando su importancia como motor dinámico de las actividades sociales, culturales y productivas bonaerenses y la riqueza identitaria de su enorme territorio.Tópico 6: Patrimonio Urbano de los siglos XVIII al XX. Técnicas de Limpieza y de Conservación
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