Quantifying robustness of biochemical network models

BACKGROUND: Robustness of mathematical models of biochemical networks is important for validation purposes and can be used as a means of selecting between different competing models. Tools for quantifying parametric robustness are needed. RESULTS: Two techniques for describing quantitatively the robustness of an oscillatory model were presented and contrasted. Single-parameter bifurcation analysis was used to evaluate the stability robustness of the limit cycle oscillation as well as the frequency and amplitude of oscillations. A tool from control engineering – the structural singular value (SSV) – was used to quantify robust stability of the limit cycle. Using SSV analysis, we find very poor robustness when the model's parameters are allowed to vary. CONCLUSION: The results show the usefulness of incorporating SSV analysis to single parameter sensitivity analysis to quantify robustness

Pruebas inmunológicas e inmunohistoquímicas en Medicina Bucal. Parte II

En este segundo artículo sobre las pruebas inmunológicas e inmunohistoquímicas utilizadas en Medicina Bucal, se revisan los métodos de detección de antígenos o anticuerpos específicos de diversas enfermedades no necesariamente autoinmunes, también las técnicas de identificación de linfocitos T o B, los análisis de las funciones efectoras de los linfocitos, las pruebas de inmunotluorescencia y algunos tests diagnósticos específicos

Presencia de Helicobacter Pylori en la placa bacteriana dental

El Helicobacter Pylori (HP) es el microorganismo causal más importante relacionado con la gastritis crónica del tipo B del antro gástrico y el principal factor asociado a la recidiva de la úlcera duodenal. Probablemente también esté asociado a la presencia de ulceración gástrica y al cáncer gástrico. Desde el año 1989 diversos estudios han planteado la posibilidad de que el germen tuviera como reservorio la placa bacteriana dental (PB). Esta podría ser la causa de la recolonización del estómago tras el tratamiento de la infección y por tanto responsable de las recidivas. La relevancia del hallazgo del HP en la PB, es aún poco clara ya que se precisan estudios de alta especificidad y sensibilidad como para asegurar que el germen detectado como HP lo sea en realidad. En este artículo revisamos la bibliografía sobre este controvertido tema

Simulation Optimization for Healthcare Emergency Departments

AbstractThis article presents an Agent-Based modeling (ABM) simulation to design a decision support system (DSS) for Healthcare Emergency Department (ED). This DSS aims to aid EDs heads in setting up management guidelines to improve the operation of EDs. This ongoing research is being performed by the Research Group in Individual Oriented Modeling (IoM) at the University Autonoma of Barcelona (UAB) with close collaboration of Hospital ED Staff Team. The objective of the proposed ABM procedure is to optimize the performance of such complex and dynamic Healthcare EDs, because worldwide most of them are overcrowded, and unable to provide ad hoc care, quality and service. Exhaustive search (ES) optimization is used to find out the optimal ED staff configuration, which includes doctors, triage nurses, and admission personnel, i.e., a multidimensional problem. An index is proposed to minimize patient length of stay in the ED. The results obtained by using an alternative pipeline scheme to ES are promising and a better understanding of the problem is achieved. The impact of the pipeline scheme to reduce the computational cost of exhaustive search is outlined

An Agent-Based Decision Support System for Hospitals Emergency Departments

AbstractModeling and simulation have been shown to be useful tools in many areas of the Healthcare operational management, field in which there is probably no area more dynamic and complex than hospital emergency departments (ED). This paper presents the results of an ongoing project that is being carried out by the Research Group in Individual Oriented Modeling (IoM) of the University Autonoma of Barcelona (UAB) with the participation of Hospital of Sabadell ED Staff Team. Its general objective is creating a simulator that, used as decision support system (DSS), aids the heads of the ED to make the best informed decisions possible. The defined ED model is a pure Agent-Based Model, formed entirely of the rules governing the behavior of the individual agents which populate the system. Two distinct types of agents have been identified, active and passive. Active agents represent human actors, meanwhile passive agents represent services and other reactive systems. The actions of agents and the communication between them will be represented using Moore state machines extended to include probabilistic transitions. The model also includes the environment in which agents move and interact. With the aim of verifying the proposed model an initial simulation has been created using NetLogo, an agent-based simulation environment well suited for modeling complex systems

Using an Agent-based Simulation for Predicting the Effects of Patients Derivation Policies in Emergency Departments

AbstractThe increasing demand of urgent care, overcrowding of hospital emergency departments (ED) and limited economic resources are phenomena shared by health systems around the world. It is estimated that up to 50% of patients that are attended in ED have non complex conditions that could be resolved in ambulatory care services. The derivation of less complex cases from the ED to other health care devices seems an essential measure to allocate properly the demand of care service between the different care units. This paper presents the results of an experiment carried out with the objective of analyzing the effects on the ED (patients’ Length of Stay, the number of patients attended and the level of activity of ED Staff) of different derivation policies. The experiment has been done with data of the Hospital of Sabadell (a big hospital, one of the most important in Catalonia, Spain), making use of an Agent-Based model and simulation formed entirely of the rules governing the behaviour of the individual agents which populate the ED, and due to the great amount of data that should be computed, using High Performance Computing

SED, Metallicity and Age of Halo Globular Clusters in M33

In this paper we study the properties of ten halo globular clusters in the nearby spiral galaxy M33. CCD images of M33 were obtained as a part of the BATC Colour Survey of the sky in 13 intermediate-band filters from 3800 to 10000{\AA}. By aperture photometry, we obtain the spectral energy distributions (SEDs) of these globular clusters. We estimate the ages of our sample clusters by comparing the photometry of each object with theoretical stellar population synthesis models for different values of metallicity. Our results suggest that eight of the ten sample halo globular clusters have ``intermediate'' ages, i.e. between 1 and 8 Gyrs.Comment: 9 pages, 3 figures, has been accepted for publication in Astronomy and Astrophysic

APPL1 antagonises Tribble 3 in regulating hepatic glucose production through fine-tuning insulin-evoked Akt signalling

Poster Session 2: Genes & Signaling - abstract no. 46: Endocrinologypublished_or_final_versionThe 15th Annual Research Conference of the Department of Medicine, The University of Hong Kong, Hong Kong, 16 January 2010. In Hong Kong Medical Journal, 2010, v. 16, suppl. 1, p. 15, abstract no. 1