2,336 research outputs found
Proposal of a P300-based BCI Speller using a predictive Text system
This paper presents a P300-based BCI speller system that uses a virtual 4 x 3 keyboard based on the T9 interface developed on mobile phones in order to increase the writing speed. To validate the effectiveness of the proposed BCI, we compared it with two adaptations of the classical Farwell and Donchin speller, which is based on a 6 x 6 symbol matrix. Three healthy subjects took part in the experiment. The preliminary results confirm the effectiveness of T9-based speller, since the time needed to spell words and complete sentences was considerably reduced.This work was partially supported by the Innovation, Science and Enterprise Council of the Junta de Andalucía (Spain), project P07-TIC-03310, the Spanish Ministry of Science and Innovation, project TEC 2011-26395 and by the European fund ERDF
Factores psicológicos en la implementación de sistemas de interfaces cerebro-ordenador (BCI)
Un sistema BCI (Brain Computer Interface) es una interfaz entre el
cerebro humano y un sistema artificial, tal como un ordenador, y se basa
principalmente en el análisis de las señales electroencefalográficas (EEG).
Estas interfaces BCI permiten al cerebro usar un nuevo canal no muscular
para enviar mensajes y órdenes al mundo exterior. Estos sistemas permiten
mejorar la calidad de vida de pacientes con severas discapacidades y pueden
representar un canal viable para interactuar con su entorno. Sin embargo,
estos sistemas aún se encuentran en fase de desarrollo buscando mejorías
tanto en términos de ingeniería como en la adaptación del sistema al usuario.
Aquí, la Psicología puede colaborar con la ingeniería aportando
conocimientos acerca de la persona, sus características y su aprendizaje.
De este modo, se presentan 3 estudios con el objetivo de propiciar
mejorías en los sistemas BCI. En el primer estudio se propone el
moldeamiento (Skinner, 1938), como una estrategia que busca optimizar el
entrenamiento del usuario en BCI a partir de un procedimiento estándar,
cambiando las contingencias progresivas para el mejor aprendizaje de las
respuestas neuronales.
El segundo estudio busca verificar si la exposición del usuario a
estímulos distractores ocasionaría un cambio en el manejo de un sistema BCI.
Se compara aquí, la navegación en dos entornos virtuales (con y sin
estimulación compleja) que simulan un entorno real.
El tercer estudio propone evaluar las características de tres teclados
ortográficos virtuales (matriz Speller), contrastando éstas con el nivel de
concentración del usuario.
Se concluye que la técnica de moldeamiento es bastante más eficaz
para el entrenamiento en un sistema BCI. Por otro lado, se respalda el
entrenamiento en entornos virtuales más complejos y cercanos a realidad. Y,
por último, se recomienda el desarrollo de matrices ortográficas reducidas y
con mayor dinamismo. Creemos que estudios como los aquí presentados
contribuyen al desarrollo de un sistema BCI y confirman las aportaciones que
la Psicología puede realizar en esta área tan innovadora
Use of a psychological learning technique to improve brain-computer interface (BCI) control
A Brain-Computer Interface (BCI) is a system that connects the human brain to a computer, allowing their users to communicate or control external devices using brain signals. Performance of BCI depends on the ability of subjects to control their own electroencephalographic (EEG) patterns, being necessary to provide suitable neurofeedback training techniques.
The main objective of this work is to use a psychological learning technique in order to help users to acquire specific skills on the control of a BCI. The feedback provided to the subject was based on virtual reality techniques.
The well-known Skinner´s shaping method (based on successive approximations) was used to reinforce two mental tasks: imagination of right hand movements and an idle state, such as mental relaxation. Two groups (5 and 4 subjects each) participated in the same number of training sessions; a control group used a standard procedure and the other group tested the shaping proposal. Both mental tasks were considered separately, so each one received different shaping levels depending on the initial control and the evolution through the training sessions. The shaping effect was implemented by modifying the feedback that users received.
The study proved the effectiveness of the proposed method by enhancing the difference between the EEG responses corresponding to these two mental tasks.
The use of a specific psychological learning technique in order to shape mental activity improved the training process over the control of a BCI, by adapting to the real needs of each user.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
A Brain–Computer Interface Speller with a Reduced Matrix: A Case Study in a Patient with Amyotrophic Lateral Sclerosis
Visual P300-based Brain–Computer Interface (BCI) paradigms for spelling are aimed at offering a non-muscular communication channel for those people with severe motor impairment, such as locked-in patients. To be as effective as other assistive technologies, these systems have to achieve a greater communication rate. One way to do so is to develop better interfaces. In this regard, we thought of using a 4 x 3 symbol matrix based on the T9 interface developed for mobile phones. Due to presenting a reduced matrix and relying on an adaptation of the T9 predictive text system, we expected that this speller would provide a higher communication rate than usual 6 x 6 matrix spellers that are based on Farwell and Donchin’s classic proposal. As a proof of concept, a locked-in patient with amyotrophic lateral sclerosis tested our T9-like visual BCI speller along with two different 7 x 6 conventional matrix spellers. The comparison of her performance results with those of a sample of three healthy participants suggested that it was possible for this locked-in patient to control the T9-like speller as well as they did, and thus, write a target sentence considerably faster than when she used the alternative spellersUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tec
Адаптації громадської будівлі – пам’ятки архітектури для маломобільних груп населення (на прикладі музею видатних харків’ян імені К.І. Шульженко)
Objetivo: analisar as complicações vasculares de pacientes submetidos a procedimentos cardiológicos endovasculares em laboratório de hemodinâmica de três centros de referência. Método: estudo de coorte multicêntrico, em três instituições de referência, sendo a amostra constituída de 2.696 pacientes, incluindo pacientes adultos que realizaram procedimento percutâneo cardiológico em caráter eletivo ou urgente. Foram considerados como desfechos a presença de complicações vasculares, como hematoma no local da punção arterial, sangramento maior e menor e correção cirúrgica para hemorragia retroperitoneal, pseudoaneurisma ou formação de fístula arteriovenosa. Resultados: dos 2.696 pacientes, 237 (8,8%) apresentaram algum tipo de complicação vascular no sítio de punção arterial. O número total de complicações vasculares foi 264: hematoma menor <10 cm (n=135), sangramento estável (n=86), hematoma maior ≥10 cm (n=32) e sangramento instável (n=11). Não ocorreu evento de hematoma retroperitoneal, pseudoaneurisma ou fístula arteriovenosa. Majoritariamente, tanto as complicações maiores como as menores ocorreram nas primeiras seis horas após o procedimento. Conclusão: os resultados das complicações no cenário atual da cardiologia intervencionista indicam que a incidência dessas ocorre predominantemente nas primeiras seis horas após os procedimentos, considerando a avaliação até 48 horas. Medidas preventivas imediatas aos procedimentos devem ser planejadas e implementadas pela equipe.Objetivo: analizar las complicaciones vasculares de pacientes sometidos a procedimientos cardiológicos endovasculares en laboratorio de hemodinámica, en tres centros de referencia. Método: fue diseñado un estudio de cohorte multicéntrica en tres instituciones de referencia. La muestra estuvo constituida por 2.696 pacientes; fueron incluidos pacientes adultos que realizaron procedimiento percutáneo cardiológico en carácter electivo o urgente; los que fueron considerados como resultado de la presencia de complicaciones vasculares, como: hematoma en el local de la punción arterial; hemorragia mayor y menor y corrección quirúrgica para hemorragia retroperitoneal, pseudoaneurisma o formación de fístula arterial venosa. Resultados: de los 2.696 pacientes, 237(8,8%) presentaron algún tipo de complicación vascular en el sitio de la punción arterial. El número total de complicaciones vasculares fue 264: hematoma menor <10cm (n=135), hemorragia estable (n=86), hematoma mayor ≥10cm (n=32) y hemorragia inestable (n=11). No ocurrió evento de hematoma retroperitoneal, pseudoaneurisma o fístula arterial venosa. En su mayoría, tanto las complicaciones mayores como las menores ocurrieron en las primeras seis horas después del procedimiento. Conclusión: los resultados de las complicaciones, en el escenario actual de la cardiología intervencionista, indican que la incidencia de ellas ocurre predominantemente en las primeras seis horas después de los procedimientos, considerando la evaluación hasta 48h. Medidas preventivas inmediatas a los procedimientos deben ser planificadas e implementadas por el equipo.Objective: to analyze vascular complications among patients who underwent endovascular cardiac procedures in the hemodynamic laboratories of three referral centers. Method: a multicenter cohort study was conducted in three referral facilities. The sample was composed of 2,696 adult patients who had undergone elective or urgent percutaneous cardiac procedures. The outcomes were vascular complications, such as: hematoma at the site of the arterial puncture; major or minor bleeding; surgical correction for retroperitoneal hemorrhage; pseudoaneurysm; and arteriovenous fistula. Results: 237 (8.8%) of the 2,696 patients presented a vascular complication at the site of the arterial puncture. The total number of vascular complications was 264: minor hematoma<10cm (n=135); stable bleeding (n=86); major hematoma ≥10cm (n=32); and unstable bleeding (n=11). There were no retroperitoneal hematoma events, pseudoaneurysm or arterial venous fistula. Most of the major and minor complications occurred in the first six hours after the procedure. Conclusion: the results concerning the current context of interventional cardiology indicate that the complications predominantly occur in the first six hours after the procedure, considering a 48-hour follow-up. The staff should plan and implement preventive measures immediately after the procedures
Availability of urinary albumin measurement in Southern Brazilian laboratories
Introduction: Diabetic kidney disease (DKD) is the leading worldwide cause of end-stage renal disease. The current recommendation is to screen for DKD by evaluating estimated glomerular filtration rate (eGFR) and measuring urinary albumin (UA) levels in a spot sample. The aim of this study was to evaluate the availability of UA measurement in Southern Brazilian laboratories. Methods: A cross-sectional study was conducted to assess the routine use of UA in all laboratories registered in the State Pharmacy Council ofRio Grande do Sul, the southernmost state ofBrazil. Data was collected by mail, e-mail, telephone, or personal interview. A sample size of at least 384 laboratories was necessary to achieve 5% precision at a 95% confidence level based on a fixed proportion of 0.5. Results: Eight hundred and eighty laboratories currently registered in the state were invited to participate in the study; 548 (62%) answered the technical specification questionnaire. Only 306 (55%) of the 548 surveyed laboratories performed UA measurements. The laboratories were also required to provide the number of UA measurements performed per day, which ranged from less than one per week to 65 per day. Conclusion: The availability of UA measurements is undesirably low inSouthern Brazil. This demonstrates the urgent need to increase the availability of this important test. It also reveals the gap between the current guidelines and the awareness about them among health care professionals.
Nurses' performance in classifying heart failure patients based on physical exam : comparison with cardiologist's physical exam and levels of N-terminal pro-B-type natriuretic peptide
Aim.The purpose of this study is to compare clinical assessment of congestion performed by a nurse to that performed bycardiologist and correlate them with NT-ProBNP levels.Background.The nurses’ role in heart failure has been strongly focused in therapeutic, educational and self-care interventions.The diagnostic performance of nurses in heart failure outpatients is not well explored. N-terminal pro-B-type natriuretic peptideis a cardiac marker that reflects elevated filling pressures.Design.Cross-sectional contemporaneous study.Methods.Heart failure outpatients underwent a systematic clinical assessment of clinical congestion score performed by car-diologist and nurse during the same visit. Assessments were performed independently and N-terminal pro-B-type natriureticpeptide levels obtained. The nurses’ ability to classify patients in hemodynamic profile was compared to the cardiologist’s.Results.Eighty-nine assessments were performed in 63 patients with heart failure. The correlation of clinical congestion scoresobtained by nurse with those obtained by cardiologist wasrs=0Æ86;p<0Æ001. The correlation of clinical congestion scoresfrom nurse and cardiologist with levels of N-terminal pro-B-type natriuretic peptide were as follows:rs=0Æ45;p<0Æ0001 andrs=0Æ51, respectively,p<0Æ0001. Patients with clinical congestion score‡3 had levels of NT-ProBNP significantly higher thanthose with clinical congestion score<3, in the assessment performed by the cardiologist (1866 SD 1151 vs. 757 SD 988 pg/ml;p<0Æ0001) and by the nurse (1720 SD 1228 vs. 821 SD 914 pg/ml;p<0Æ0001). The nurse and cardiologist had similarcapacity in classifying patients in congested quadrants (p=0Æ027) or in dry quadrants (p=0Æ03), according to the levels ofN-terminal pro-B-type natriuretic peptide. Area under the receiver-operating characteristic curve of the nurse and cardiologist todetect congestion was, respectively, 0Æ77 and 0Æ72. Conclusions.Our data suggests that nurses trained in heart failure may have a similar performance to that of the cardiologistfor the clinical detection of congestion and assessment of the hemodynamic profile in patients with chronic heart failure
Análisis de submuestras del score de riesgo para complicaciones vasculares en dos centros públicos de referencia para cardiología intervencionista
Evaluate the performance of the Vascular Complications Risk Score in two public referral centers for interventional cardiology. Method: Subsample analysis of the Vascular Complications Risk Score, which was developed and validated in the catheterization laboratories of three cardiology referral centers (two public, one private) with a cutoff of <3 for no risk of developing vascular complications and ≥3 for risk. In this new analysis, we excluded data from the private facility, and only included participants from the original (validation) cohort of the two public hospitals. Results: Among the 629 patients studied, 11.8% had vascular complications; of these, 1.8% were major and 10% minor. Among the patients with a score <3, 310 (94.5%) presented no vascular complications; of those with a score ≥3, 50 (17%) developed complications. Of those who developed vascular complications, 18 scored <3; two of these had major complications. Conclusion: This subanalysis confirms the ability of the Vascular Complications Risk core to predict low risk of vascular complications in patients with a score < 3
MONITORAMENTO DA QUALIDADE DA ÁGUA E AVALIAÇÃO DA CAPACIDADE DE AUTODEPURAÇÃO DO RIO LIGEIRO NO MUNICÍPIO E PATO BRANCO - PR
Este estudo teve como objetivo realizar o monitoramento da qualidade da água para a avaliação da capacidade de autodepuração do Rio Ligeiro, desde uma das nascentes até a confluência com o Rio Chopim. Estabeleceram-se seis pontos de monitoramento (PM01 a PM06) ao longo do percurso. Foram realizadas coletas de amostras de água nas diferentes estações do ano de 2017, para análises de oxigênio dissolvido (OD), demanda bioquímica de oxigênio (DBO) e mensuração da temperatura. Além disso, foram realizadas medições hidrológicas em todos os PM. Com base nos resultados das análises laboratoriais realizou-se a calibração do modelo QUAL-UFMG para a avaliação da capacidade de autodepuração. A modelagem da qualidade da água, na campanha de inverno, foi a que apresentou maior grau de deterioração da qualidade da água, com baixos níveis de OD e elevada concentração de DBO, indicando que no período de estiagem reduz-se a capacidade de diluição frente aos despejos de efluentes. Conclui-se que o Rio Ligeiro encontra-se deteriorado desde a nascente e que a sua capacidade de autodepuração apresenta condições críticas no período de menor vazão
Nuclear Shell Model Calculations with Fundamental Nucleon-Nucleon Interactions
Some fundamental Nucleon-Nucleon interactions and their applications to
finite nuclei are reviewed. Results for the few-body systems and from
Shell-Model calculations are discussed and compared to point out the advantages
and disadvantages of the different Nucleon-Nucleon interactions. The recently
developed Drexel University Shell Model (DUSM) code is mentioned.Comment: 16 pages, 4 figures. To appear in Phys. Rep. 199
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