Cooperative RNA Polymerase Molecules Behavior on a Stochastic Sequence-Dependent Model for Transcription Elongation

The transcription process is crucial to life and the enzyme RNA polymerase (RNAP) is the major component of the transcription machinery. The development of single-molecule techniques, such as magnetic and optical tweezers, atomic-force microscopy and single-molecule fluorescence, increased our understanding of the transcription process and complements traditional biochemical studies. Based on these studies, theoretical models have been proposed to explain and predict the kinetics of the RNAP during the polymerization, highlighting the results achieved by models based on the thermodynamic stability of the transcription elongation complex. However, experiments showed that if more than one RNAP initiates from the same promoter, the transcription behavior slightly changes and new phenomenona are observed. We proposed and implemented a theoretical model that considers collisions between RNAPs and predicts their cooperative behavior during multi-round transcription generalizing the Bai et al. stochastic sequence-dependent model. In our approach, collisions between elongating enzymes modify their transcription rate values. We performed the simulations in Mathematica® and compared the results of the single and the multiple-molecule transcription with experimental results and other theoretical models. Our multi-round approach can recover several expected behaviors, showing that the transcription process for the studied sequences can be accelerated up to 48% when collisions are allowed: the dwell times on pause sites are reduced as well as the distance that the RNAPs backtracked from backtracking sites. © 2013 Costa et al.

Capital goods: size of markets, sectoral structure and demand prospects in Latin America

Includes bibliography

Energy demand in Chilean manufacturing

Includes bibliography

Methodology for forecasting electric power demand

Includes bibliography

Ergodic crossover in partially self-avoiding stochastic walks

Consider a one-dimensional environment with N randomly distributed sites. An agent explores this random medium moving deterministically with a spatial memory μ. A crossover from local to global exploration occurs in one dimension at a well-defined memory value μ1=log2N. In its stochastic version, the dynamics is ruled by the memory and by temperature T, which affects the hopping displacement. This dynamics also shows a crossover in one dimension, obtained computationally, between exploration schemes, characterized yet by the trajectory size (Np) (aging effect). In this paper we provide an analytical approach considering the modified stochastic version where the parameter T plays the role of a maximum hopping distance. This modification allows us to obtain a general analytical expression for the crossover, as a function of the parameters μ, T, and Np. Differently from what has been proposed by previous studies, we find that the crossover occurs in any dimension d. These results have been validated by numerical experiments and may be of great value for fixing optimal parameters in search algorithms. © 2013 American Physical Society.

Aplicações de sistemas multiagentes na previsão espacial de demanda elétrica em sistemas de distribuição

Pós-graduação em Engenharia Elétrica - FEIS

Latin American supply and major world market demand for the principal metals, 1970-1990: aluminium, copper, iron, nickel, lead, zinc, tin

Includes bibliography

Demanda de maquinaria y equipo de la minería metalífera en algunos países de América Latina = Demand for machinery and equipment by the metal mining industry in some countries of Latin America

Incluye Bibliografía

Shipping suply and demand, biennium 2008 - 2009

This edition of the FAL Bulletin analyses the performance of the shipping industry during the biennium 2008-2009 in its three main markets: containers, dry-bulk cargoes and liquid bulk (oil and its derivatives).

Changes in maritime transport supply and demand

This FAL bulletin reviews changes in water transport supply and demand in three markets: containers, dry bulk and liquid cargo (dirty and clean) over the past several years.

Towards diversification of the tourism sector: A recreational demand study of yachting and marina services in the Caribbean

Includes bibliography.

Social mobility and the demand for income redistribution in Latin America

Includes bibliography