Rotenone selectively occludes sensitivity to hypoxia in rat carotid body glomus cells

Carotid body glomus cells release transmitters in response to hypoxia due to the increase of excitability resulting from inhibition of O2 -regulated K+ channels. However, the mechanisms involved in the detection of changes of O2 tension are unknown. We have studied the interaction between glomus cell O2 sensitivity and inhibition of the mitochondrial electron transport chain (ETC) in a carotid body thin slice preparation in which catecholamine release from intact single glomus cells can be monitored by amperometry. Inhibition of the mitochondrial ETC at proximal and distal complexes induces external Ca2+-dependent catecholamine secretion. At saturating concentration of the ETC inhibitors, the cellular response to hypoxia is maintained. However, rotenone, a complex I blocker, selectively occludes the responsiveness to hypoxia of glomus cells in a dose-dependent manner. The effect of rotenone is mimicked by 1-methyl-4-phenylpyridinium ion(MPP+), an agent that binds to the same site as rotenone, but not by complex I inhibitors acting on different sites. In addition, the effect of rotenone is not prevented by incubation of the cells with succinate, a substrate of complex II. These data strongly suggest that sensitivity to hypoxia of carotid body glomus cells is not linked in a simple way to mitochondrial electron flow and that a rotenone (and MPP+)-sensitive molecule critically participates in acute oxygen sensing in the carotid body.Ministerio de Ciencia y Tecnología 1FD97–161

Evolutionary processes in the development of errors in subtraction algorithms

[EN] The study of errors made in subtraction is a research subject approached from different theoretical premises that affect different components of the algorithmic process as triggers of their generation. In the following research an attempt has been made to investigate the typology and nature of errors which occur in subtractions and their evolution throughout primary education. The main aim of the research is to examine whether in our school context systematic errors are made and if these decrease throughout schooling. In order to do this, we carried out a rigorous analysis of over 7140 subtractions done by children of 7 to 13 years of age in 2nd, 3rd, 4th, 5th and 6th years of primary school, using a sample of 357 primary school students who were tested with the VanLehn 20 subtractions test. The SPSS 11.5 computer programme was used to analyze the data generated by the tests. One hundred and twenty-two different errors were analyzed, the results showing systematic errors in 55% of the cases. We likewise found that the evolution of the error throughout primary education shows certain similarities with the results obtained in other teaching contexts. The results obtained are undoubtedly valuable for programming the teaching process

Análisis del error sistemático en la sustracción

En este artículo presentamos resultados de investigación relacionados con la tipología, naturaleza y evolución de los errores en la sustracción. El objetivo principal de la investigación trata de indagar sobre si en nuestro contexto escolar se producen errores sistemáticos y si disminuyen a lo largo de la escolaridad. Asimismo, comparamos los resultados obtenidos con los aportados por autores de referencia en este campo de investigación. Para ello, efectuamos un análisis sobre 7.140 restas realizadas por niños/as escolarizados en 2º, 3º, 4º, 5º y 6º de Educación Primaria. Los resultados demuestran la existencia de errores sistemáticos y tipología concreta de los mismos, hecho de indudable valor a la hora de programar didácticamente el proceso de enseñanza.In this article, we presented results related to the typology, nature and evolution of the errors in subtraction. The main aim, is to examine if in our school context systematic errors take place and if these decrease throughout schooling. Also, we compared our results with the ones contributed by authors of reference in this field of research. To do so, we carried out an analysis on 7140 subtractions made by children in our educational system. The results demonstrate the existence of systematic errors in our scholastic context, a fact of doubtless value when programming the learning process didactically

Validation of the ICH score in patients with spontaneous intracerebral haemorrhage admitted to the intensive care unit in Southern Spain

Objective Validation of the intracerebral haemorrhage (ICH) score in patients with a diagnosis of spontaneous ICH admitted to the intensive care unit (ICU). Results A total of 336 patients were included. 105 of whom underwent surgery. Median (IQR) age: 62 (50–70) years. APACHE-II: 21(15–26) points, GCS: 7 (4–11) points, ICH score: 2 (2–3) points. 11.1% presented with bilateral mydriasis on admission (mortality rate=100%). Intraventricular haemorrhage was observed in 58.9% of patients. In-hospital mortality was 54.17% while the APACHE-II predicted mortality was 57.22% with a standardised mortality ratio (SMR) of 0.95 (95% CI 0.81 to 1.09) and a Hosmer-Lemenshow test value (H) of 3.62 (no significant statistical difference, n.s.). 30-day mortality was 52.38% compared with the ICH score predicted mortality of 48.79%, SMR: 1.07 (95% CI 0.91 to 1.23), n.s. Mortality was higher than predicted at the lowest scores and lower than predicted in the more severe patients, (H=55.89, p<0.001), Gruppo Italiano per la Valutazione degli Interventi in Terapia Intensiva calibration belt (p<0.001). The area under a receiver operating characteristic (ROC) curve was 0.74 (95% CI 0.69 to 0.79). Conclusions ICH score shows an acceptable discrimination as a tool to predict mortality rates in patients with spontaneous ICH admitted to the ICU, but its calibration is suboptimal

Extended health visibility in the hospital environment

Wireless sensor networks can help healthcare providers enhance patient monitoring and communication capabilities. This paper describes the present state of the development of a vital signal monitoring network applied to the hospital environment. The proposed network is based on non-obstructive sensors able to communicate through a low power wireless sensor network based on the ZigBee protocol. This network enables continuous patient monitoring, creating entirely new mechanisms for providing healthcare under a plethora of cases (e.g. post-op, continuous care, and chronic diseases). The main advantages of this system include increased patient mobility, faster detection of potential problems, real-time feedback to caregivers and patients, and faster response to emergency situations.Fundação para a Ciência e a Tecnologia (FCT)Grupo AMI – Assistência Médica Integral (Casa de Saúde Guimarães, SA

Towards the design of efficient nonbeacon-enabled ZigBee networks

This paper presents experimental results of the communication performance evaluation of a prototype ZigBee-based patient monitoring system commissioned in an in-patient floor of a Portuguese hospital (HPG – Hospital Privado de Guimar~aes). Besides, it revisits relevant problems that affect the performance of nonbeacon-enabled ZigBee networks. Initially, the presence of hidden-nodes and the impact of sensor node mobility are discussed. It was observed, for instance, that the message delivery ratio in a star network consisting of six wireless electrocardiogram sensor devices may decrease from 100% when no hidden-nodes are present to 83.96% when half of the sensor devices are unable to detect the transmissions made by the other half. An additional aspect which affects the communication reliability is a deadlock condition that can occur if routers are unable to process incoming packets during the backoff part of the CSMA-CA mechanism. A simple approach to increase the message delivery ratio in this case is proposed and its effectiveness is verified. The discussion and results presented in this paper aim to contribute to the design of efficient networks, and are valid to other scenarios and environments rather than hospitals.Fundação para a Ciência e a Tecnologia (FCT)Grupo AMI – Assistência Médica Integral (Casa de Saúde Guimarães, SA

New insights on the structural and optical properties of Ce–Ti mixed oxide nanoparticles doped with praseodymium

Nanostructured, doped Ce–Ti mixed oxides are potential materials for several applications such as pigments, catalysis, fuel cells, optical films, and gas sensors. In this article, a series of Pr-doped Ce–Ti oxides have been prepared by the solvothermal method. These compounds were characterized by XRD, Raman, N2 sorption, SEM and UV–VIS spectrophotometry techniques. The experimental results suggest that spherical morphology, nanocrystalline particles and high specific surface area (up to 180 m2 g-1) are achieved at low temperature with this free surfactant methodology. Under basic conditions, a single phase product is identified at high temperature (1000 ºC), while for acid or neutral conditions, secondary phases appear. Different colored materials, ranging from yellow to red, are obtained by varying the firing temperature, quantity of doping praseodymium and the pH of the reaction. The chemical stability of these oxides was tested in some industrial polymers or glazes

Developing Competencies for Rural Development Project Management through Local Action Groups: The Punta Indio (Argentina) Experience

This chapter provides the foundations for a new approach in competence development for rural development project management, involving the role of higher education in the solution of real-life problems. This experience took place in senior courses at La Plata University and included the participation of students from this university. The research was carried out in Punta Indio, which is affected by rural depopulation, as are the rest of the territories inside the Buenos Aires Province. The process is developed through project-based learning (PBL) and the basis of the working with people (WWP) model, involving project management competencies according to the International Project Management Association (IPMA) standards. In the formation of local action groups (LAGs,) elements from the LEADER (Liaisons Entre Activités de Developement de l’Economie Rural) rural development model—applied in the rural territories inside the EU—were taken into account

Subtraction: More than an Algorithm?

[EN] One of the aims of compulsory education is for students to adequately handle basic maths, owing to its importance in their future professional and personal lives. However, mechanical knowledge of an algorithm may not be sufficient to train future citizens with critical and creative thinking if it is not accompanied by a comprehensive understanding of the concept. In this regard, existing research shows that a high percentage of students in primary education commit errors when they attempt subtraction. However, little is known about whether adults perform the same calculations correctly. In this context, 535 university students completed a questionnaire composed of 20 subtractions. The results showed that only one quarter of respondents performed the subtractions correctly. Analysis of error type showed that the most frequent mistakes corresponded to the systematic errors made by primary-level students. This may indicate that the types of errors committed during early learning persist over time, implying that subtraction may not have been adequately taught. New educational approaches and initiatives are required to encourage the teaching and learning of subtraction in a more reasoned and critical manner during early learning