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A low-density barium photoplasma has been generated by two-step photoionization in an atomic beam. The transition from independent particle nature to collective effects has been observed in a V-shaped potential well. The potential is produced by a plate–grid–plate geometry in which the grid is negatively biased while the plates are grounded. Analytical expressions for the ion currents on the plates and grid have been deduced for a charge particle moving in the potential well and compared with experiments. The results are in good agreement and gave a method to estimate the ion transmission factor for the grid. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Presents a study that simulated in two dimensions the expansion of a plasma biased plane parallel electrodes using the particle-in-cell method. Description of the motion of the electrons and ions; Plasma decay time constant and ambipolar diffusion coefficient; Description of the plasma characteristics.

M.G. Dominguez-Bello [1] G.I. Perez-Perez [2] N. Pacheco [1] E. Gonzalez [3] E. Garza-Gonzalez [4] R. Mora [3] V. Mago [5] I. Gomez [5] [6/22] Seroprevalence of Helicobacter pylori and [...]

G.I. Perez-Perez [1] M.G. Dominguez-Bello [2] C. Ghose [1] N. Pacheco [2] E. Gonzalez [3] V. Mago [4] P. Gueneau de Novoa [2] I. Gomez [4] R. Mora [3] M.J. [...]

A new method for release of severe mentosternal contractures has been described in this paper under central neuraxial blockade. The contracture release was performed under thoracic epidural analgesia. This technique can benefit patients with mentosternal contractures to avoid the problems of entubation and it can also assist in postoperative recovery and analgesia. The epidural catheter can be used to extend the height or duration of intraoperative block and is also useful to provide postoperative epidural analgesia.

Abstract Background Meningitis is characterized by an inflammation of the meninges, or the membranes surrounding the brain and spinal cord. Early diagnosis and treatment is crucial for a positive outcome, yet identifying meningitis is a complex process involving an array of signs and symptoms and multiple causal factors which require novel solutions to support clinical decision-making. In this work, we explore the potential of fuzzy cognitive map to assist in the modeling of meningitis, as a support tool for physicians in the accurate diagnosis and treatment of the condition. Methods Fuzzy cognitive mapping (FCM) is a method for analysing and depicting human perception of a given system. FCM facilitates the development of a conceptual model which is not limited by exact values and measurements and thus is well suited to representing relatively unstructured knowledge and associations expressed in imprecise terms. A team of doctors (physicians), comprising four paediatricians, was formed to define the multifarious signs and symptoms associated with meningitis and to identify risk factors integral to its causality, as indicators used by clinicians to identify the presence or absence of meningitis in patients. The FCM model, consisting of 20 concept nodes, has been designed by the team of paediatricians in collaborative dialogue with the research team. Results The paediatricians were supplied with a form containing various input parameters to be completed at the time of diagnosing meningitis among infants and children. The paediatricians provided information on a total of 56 patient cases amongst children whose age ranged from 2 months to 7 years. The physicians’ decision to diagnose meningitis was available for each individual case which was used as the outcome measure for evaluating the model. The FCM was trained using 40 cases with an accuracy of 95%, and later 16 test cases were used to analyze the accuracy and reliability of the model. The system produced the results with sensitivity of 83.3% and specificity of 80%. Conclusions This work suggests that the application and development of a knowledge based system, using the formalization of FCMs for understanding the symptoms and causes of meningitis in children and infants, can provide a reliable front-end decision-making tool to better assist physicians.