v.9 n.6 October
Cover:
Dr. Abhijit Mitra and his team on field research.
Carbon Trading: Is the concept very volatile?
Abhijit Mitra, Sana Ahmed, Ricardo Gobato, Shampa Mitra, and Sufia Zaman
Parana J. Sci. Educ., v.9, n.6, (1-13), October 1, 2023.
Abstract
Carbon dioxide is one of the major GHGs and a driver in the domain of climate change. In the drive to mitigate and adapt with the issue of climate change, carbon trading has become a vital policy instrument in majority of the countries in the World. It is also a pivotal element of the UNFCCC’s (United Nation of Parties of Copenhagen Climate Change Conference) approach to tackle climate change. National or regional carbon trading schemes are now operational in many counties through a well-defined structural policy, specific for the country. Yet the trading is still in a volatile stage. Many schools think that this concept is not very realistic to combat climate change, while others consider this a strict regulation to put cap/limit on the emitters. Unfortunately, the subject is characterized by jargon, abstract concepts, mathematical formulae, and technical detail, making it hard for most people to understand its implications and evaluate its merits and demerits. This paper is a first order analysis to unravel some of this complexity by imparting thrust on three basic components – cap and trade, carbon offsets and carbon trading – which underpin the trade in carbon quotas. The case study of the highly urbanized city of Kolkata and Indian Sundarban mangrove ecosystem has been discussed in details with CO2 – e of dominant trees to analyze the probable credit that can be received from the producer communities of these two sites that are significantly different in terms of anthropogenic footprints and ecological features.
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Interaction of a nine steroid derivatives with aromatase enzyme surface using a theoretical model
Lauro Figueroa Valverde, Marcela Rosas Nexticapa, María Magdalena Álvarez Ramírez,
Virginia Mateu Armand, Maria Lopez Ramos, Tomas Lopez Gutierrez, Silvia Delgado Moreno, and
Juliette Mijangos Sanchez.
Parana J. Sci. Educ., v.9, n.6, (14-19), October 1, 2023.
Abstract
Some aromatase enzyme inhibitors drugs have been used to treat cancer; however, their interaction with aromatase is not clear. The aim of this study was to evaluate the possible interaction of nine steroid derivatives with aromatase enzyme surface using 3eqm protein, exemetane and formestene as theoretical tools in Docking Server program. The results showed differences in the aminoacid residues involved in the interaction of steroid derivatives (1-9) with 3eqm protein surface compared with exemetane and formestene. Besides, the inhibition constant for steroid derivatives 1, 2 and 5 was lower compared to exemetane and formestene drugs. In conclusion, the steroid derivatives 1, 2 and 5 could act as aromatase enzyme inhibitors and this phenomenon could be translated as good compounds to treat breast cancer.
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Energy Conservation in General Relativity and Flat Rotation Curves of Spiral Galaxies
Stefan Bernhard Rüster
Parana J. Sci. Educ., v.9, n.6, (20-27), October 1, 2023.
Abstract
This article shows that the vanishing covariant divergence of the energy-momentum tensor of matter is a conservation law. In addition, it is pointed out why energy-momentum pseudo-tensors of the gravitational field cannot represent the energy density of the gravitational field, but, apart from a factor, is described by the Einstein tensor. The necessarily existing conservation law of total energy, momentum and stress in general relativity is derived, thereby solving the cosmological constant problem as well as that of dark energy and dark matter. In Newton’s theory of gravitation, it is the modified Poisson equation that approximately meets the requirement of conservation of total energy. A simple but fairly accurate model, consistent with observations, is presented, solving the modified Poisson equation to fit the calculated rotation curves to the observed speeds in spiral galaxies being composed of several components: the central region of the bulge, the bulge, the disk and dark matter, the latter of which is exactly described by this model.
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