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Cardenas A.,National University of Colombia | Rodriguez-R L.M.,University of Los Andes, Colombia | Pizarro V.,Jorge Tadeo Lozano University, Bogota | Cadavid L.F.,National University of Colombia | Arevalo-Ferro C.,National University of Colombia
ISME Journal | Year: 2012

Coral reefs are deteriorating at an alarming rate mainly as a consequence of the emergence of coral diseases. The white plague disease (WPD) is the most prevalent coral disease in the southwestern Caribbean, affecting dozens of coral species. However, the identification of a single causal agent has proved problematic. This suggests more complex etiological scenarios involving alterations in the dynamic interaction between environmental factors, the coral immune system and the symbiotic microbial communities. Here we compare the microbiome of healthy and WPD-affected corals from the two reef-building species Diploria strigosa and Siderastrea siderea collected at the Tayrona National Park in the Caribbean of Colombia. Microbiomes were analyzed by combining culture-dependent methods and pyrosequencing of 16S ribosomal DNA (rDNA) V5-V6 hypervariable regions. A total of 20 410 classifiable 16S rDNA sequences reads were obtained including all samples. No significant differences in operational taxonomic unit diversity were found between healthy and affected tissues; however, a significant increase of Alphaproteobacteria and a concomitant decrease in the Beta- and Gammaproteobacteria was observed in WPD-affected corals of both species. Significant shifts were also observed in the orders Rhizobiales, Caulobacteriales, Burkholderiales, Rhodobacterales, Aleteromonadales and Xanthomonadales, although they were not consistent between the two coral species. These shifts in the microbiome structure of WPD-affected corals suggest a loss of community-mediated growth control mechanisms on bacterial populations specific for each holobiont system. © 2012 International Society for Microbial Ecology All rights reserved. Source

Bojaca C.R.,Jorge Tadeo Lozano University, Bogota | Schrevens E.,Catholic University of Leuven
Energy | Year: 2010

Scarce information is available about the energy use pattern of horticultural commodities in general and more specifically for peri-urban horticulture. Peri-urban horticulture in the outskirts of Bogota is an important source of vegetables for Colombia's capital city. Based on detailed follow-ups and periodic field measurements an output-input energy balance was performed with the main objective to study the energy use efficiency of those systems. An uncertainty analysis on the input factors and on the energy equivalents was then applied. Over a measurement period of 18-month, the energy use for coriander, lettuce, radish and spinach was investigated, respectively 12.1, 18.8, 6.6 and 10.7 GJ ha -1 were consumed in these cropping systems. Negative balances were observed for all species exception made for spinach where an output:input ratio of 1.16 was found. The two-way uncertainty analysis showed the highest uncertainty for N-based fertilization while no significant effect was observed for seeds in direct sowing crops. Sustainability of peri-urban horticulture around Bogota is compromised not only because of the city expansion but also due to its inefficient energy use. Technical improvements are required to ensure the environmental subsistence of this important sector for the metropolitan area of the city. © 2010 Elsevier Ltd. All rights reserved. Source

Campos D.,Jorge Tadeo Lozano University, Bogota | Campos D.,Colombian Academy of science
Physica A: Statistical Mechanics and its Applications | Year: 2010

A two-parameter probability distribution is constructed by dilatation (or contraction) of the escort probability distribution. This transformation involves a physical probability distribution P associated with the system under study and an almost arbitrary reference probability distribution P′. In contrast to the Shannon and Rnyi entropies, the Tsallis entropy does not decompose as the sum of the physical contribution due to P and the reference or spurious part owing to P′. For solving this problem, a slight modification to the relation between Tsallis and Rnyi entropies must be introduced. The procedure in this paper gives rise to a nonconventional one-parameter Shannon entropy and to two-parameter Rnyi and Tsallis entropies associated with P. It also contributes to clarify the meaning and role of the escort probabilities set. © 2010 Elsevier B.V. Source

Campos D.,Jorge Tadeo Lozano University, Bogota
Physica A: Statistical Mechanics and its Applications | Year: 2010

In this article, Shannon, Rényi and Tsallis entropies are considered for a system of events characterized by an arbitrary probability distribution P that can be incomplete, complete or overcomplete. After a suitable transformation that leads to the escort probabilities of P, these can be written as the canonical probability distribution for a set of pseudo-energies (Hartley information, E n = - ln P n) and a dimensionless parameter q that plays the role of thermodynamics β. Several relations between the entropies are presented, including the analysis of compound systems. The method is illustrated with an example. © 2009 Elsevier B.V. All rights reserved. Source

Campos D.,Jorge Tadeo Lozano University, Bogota
Physica A: Statistical Mechanics and its Applications | Year: 2011

This paper starts by considering an arbitrary system for which the probability distribution P:=P1,P2,...,PN of a measurable property, with N possible independent results, is known. By using the Hartley information (pseudo-energy), the escort probabilities of P and its Shannon entropy, a thermodynamic-like formalism is developed, including the deduction of the fundamental equation for the mean value of the pseudo-energies. Thus, the method allows a macrodescription of the system that is based on a purely mathematical procedure and involves thermodynamic-like variables. As a specific example we consider a bank that measures customer satisfaction by doing a statistical survey (satisfied or unsatisfied customers). © 2010 Elsevier B.V. All rights reserved. Source

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