Identidad y zozobra. Un asomo a Octavio Paz

Se presenta un ejercicio hermenéutico en torno a la poesía de Octavio Paz en el que se observaron las ideas sobre memoria, identidad y zozobra, en un discurrir generado por el diálogo entre autor y lector en convergencia de poema e historia. Esta lectura permitió elaborar una reflexión sobre la vitali - dad creadora de la palabra y el misterio del ser para la muerte.Se presenta un ejercicio hermenéutico en torno a la poesía de Octavio Paz en el que se observaron las ideas sobre memoria, identidad y zozobra, en un discurrir generado por el diálogo entre autor y lector en convergencia de poema e historia. Esta lectura permitió elaborar una reflexión sobre la vitalidad creadora de la palabra y el misterio del ‘ser para la muerte

Prediction of time series using wavelet Gaussian process for wireless sensor networks

Articulo de investigacion idizado en JCR con factor de impacto 2.2The detection and transmission of a physical variable over time, by a node of a sensor network to its sink node, represents a significant communication overload and consequently one of the main energy consumption processes. In this article we present an algorithm for the prediction of time series, with which it is expected to reduce the energy consumption of a sensor network, by reducing the number of transmissions when reporting to the sink node only when the prediction of the sensed value differs in certain magnitude, to the actual sensed value. For this end, the proposed algorithm combines a wavelet multiresolution transform with robust prediction using Gaussian process. The data is processed in wavelet domain, taking advantage of the transform ability to capture geometric information and decomposition in more simple signals or subbands. Subsequently, the decomposed signal is approximated by Gaussian process one for each subband of the wavelet, in this manner the Gaussian process is given to learn a much simple signal. Once the process is trained, it is ready to make predictions. We compare our method with pure Gaussian process prediction showing that the proposed method reduces the prediction error and is improves large horizons predictions, thus reducing the energy consumption of the sensor network

Síntesis, caracterización y evaluación de un material carbonoso con nanopartículas de Fe-Cu para la adsorción de índigo carmín en solución

Síntesis, caracterización y evaluación de un material carbonoso con nanopartículas de Fe-Cu para la adsorción de índigo carmín en solució

TRADE-OFFS BETWEEN ECONOMIC EFFICIENCY AND CONTAMINATION BY COFFEE PROCESSING A BIOECONOMIC MODEL AT THE WATERSHED LEVEL IN HONDURAS

In Honduras, traditional coffee processing is the cause of two major problems: poor coffee quality and contaminated water. In this paper we present a method that determines the trade-off between economic efficiency and contamination in a Honduran sub-watershed. The method is a bioeconomic model based on mathematical programming that stimulates the functioning of the interlinked economic and ecological processes in the sub-watershed. We compare various scenarii where the model is given the possibility of replacing traditional coffee processing plants with a network of improved ecological plants. For different levels of contamination the model determines the optimal location and size of new coffee processing plants along river streams by minimizing transport, variable and fixed costs. The restrictions of the system are the volume of wet coffee to be processed, the available stream water, and in the alternative scenarii, investment capital and contaminant concentration in the river. We apply the method to a typical sub-watershed in the hillsides of western Honduras and show that coffee quality can be improved and contamination can be reduced substantially at a relatively low cost.coffee, environment, water quality, mathematical programming, transport cost, spatial analysis, watershed, Honduras., Environmental Economics and Policy,

Reconciling kinetic and thermodynamic models of bacterial transcription

The study of transcription remains one of the centerpieces of modern biology with implications in settings from development to metabolism to evolution to disease. Precision measurements using a host of different techniques including fluorescence and sequencing readouts have raised the bar for what it means to quantitatively understand transcriptional regulation. In particular our understanding of the simplest genetic circuit is sufficiently refined both experimentally and theoretically that it has become possible to carefully discriminate between different conceptual pictures of how this regulatory system works. This regulatory motif, originally posited by Jacob and Monod in the 1960s, consists of a single transcriptional repressor binding to a promoter site and inhibiting transcription. In this paper, we show how seven distinct models of this so-called simple-repression motif, based both on thermodynamic and kinetic thinking, can be used to derive the predicted levels of gene expression and shed light on the often surprising past success of the thermodynamic models. These different models are then invoked to confront a variety of different data on mean, variance and full gene expression distributions, illustrating the extent to which such models can and cannot be distinguished, and suggesting a two-state model with a distribution of burst sizes as the most potent of the seven for describing the simple-repression motif

Reconciling Kinetic and Equilibrium Models of Bacterial Transcription

The study of transcription remains one of the centerpieces of modern biology with implications in settings from development to metabolism to evolution to disease. Precision measurements using a host of different techniques including fluorescence and sequencing readouts have raised the bar for what it means to quantitatively understand transcriptional regulation. In particular our understanding of the simplest genetic circuit is sufficiently refined both experimentally and theoretically that it has become possible to carefully discriminate between different conceptual pictures of how this regulatory system works. This regulatory motif, originally posited by Jacob and Monod in the 1960s, consists of a single transcriptional repressor binding to a promoter site and inhibiting transcription. In this paper, we show how seven distinct models of this so-called simple-repression motif, based both on equilibrium and kinetic thinking, can be used to derive the predicted levels of gene expression and shed light on the often surprising past success of the equilibrium models. These different models are then invoked to confront a variety of different data on mean, variance and full gene expression distributions, illustrating the extent to which such models can and cannot be distinguished, and suggesting a two-state model with a distribution of burst sizes as the most potent of the seven for describing the simple-repression motif

Tuning transcriptional regulation through signaling: A predictive theory of allosteric induction

Allosteric regulation is found across all domains of life, yet we still lack simple, predictive theories that directly link the experimentally tunable parameters of a system to its input-output response. To that end, we present a general theory of allosteric transcriptional regulation using the Monod-Wyman-Changeux model. We rigorously test this model using the ubiquitous simple repression motif in bacteria by first predicting the behavior of strains that span a large range of repressor copy numbers and DNA binding strengths and then constructing and measuring their response. Our model not only accurately captures the induction profiles of these strains but also enables us to derive analytic expressions for key properties such as the dynamic range and $[EC_{50}]$. Finally, we derive an expression for the free energy of allosteric repressors which enables us to collapse our experimental data onto a single master curve that captures the diverse phenomenology of the induction profiles.Comment: Substantial revisions for resubmission (3 new figures, significantly elaborated discussion); added Professor Mitchell Lewis as another author for his continuing contributions to the projec