Instituto Politécnico Nacional

About: Instituto Politécnico Nacional is a education organization based out in Mexico City, Mexico. It is known for research contribution in the topics: Population & Context (language use). The organization has 43351 authors who have published 63315 publications receiving 938532 citations. The organization is also known as: Instituto Politécnico Nacional & Instituto Politecnico Nacional.

In vitro chili pepper biotechnology

Abstract: Chili pepper is an important horticultural crop that can surely benefit from plant biotechnology. However, although it is a Solanaceous member, developments in plant cell, tissue, and organ culture, as well as on plant genetic transformation, have lagged far behind those achieved for other members of the same family, such as tobacco (Nicotiana tabacum), tomato (Lycopersicon esculentum), and potato (Solanum tuberosum), species frequently used as model systems because of their facility to regenerate organs and eventually whole plants in vitro, and also for their ability to be genetically engineered by the currently available transformation methods. Capsicum members have been shown to be recalcitrant to differentiation and plant regeneration under in vitro conditions, which in turn makes it very difficult or inefficient to apply recombinant DNA technologies via genetic transformation aimed at genetic improvement against pests and diseases. Some approaches, however, have made possible the regeneration of chili pepper plants from in vitro-cultured cells, tissues, and organs through organogenesis or embryogenesis. Anther culture has been successfully applied to obtain haploid and doubledhaploid plants. Organogenic systems have been used for in vitro micropropagation as well as for genetic transformation. Application of both tissue culture and genetic transformation techniques have led to the development of chili pepper plants more resistant to at least one type of virus. Cell and tissue cultures have been applied successfully to the selection of variant cells exhibiting increased resistance to abiotic stresses, but no plants exhibiting the selected traits have been regenerated. Production of capsaicinoids, the hot principle of chili pepper fruits, by cells and callus tissues has been another area of intense research. The advances, limitations, and applications of chili pepper biotechnology are discussed.

A multiyear dynamic approach for transmission expansion planning and long-term marginal costs computation

Abstract: This paper presents a multicriteria formulation for multiyear dynamic transmission expansion planning problems. This formulation considers three criteria: investment costs, operation costs, and the expected energy not supplied. The solution algorithm adopts an interactive decision-making approach that starts at a nondominated solution of the problem. This solution is identified transforming two of the three criteria in constraints specifying aspiration levels and using afterwards simulated annealing to deal with the integer nature of investment decisions. After obtaining this first solution, the decision maker can alter the aspiration levels and run the application again to obtain a new solution. Once an expansion plan is accepted, the algorithm computes long-term marginal costs, reflecting both investment and operation costs. These costs are more stable than short-term ones and inherently address the revenue reconciliation problem well known in short-term approaches. The developed algorithm is tested using a case study based on the Portuguese 400/220/150-kV transmission network.

Cell Adhesion, Polarity, and Epithelia in the Dawn of Metazoans

Abstract: Transporting epithelia posed formidable conundrums right from the moment that Du Bois Raymond discovered their asymmetric behavior, a century and a half ago. It took a century and a half to start u...