Human sensitivity to gearshift loads

This paper describes an investigation of the ability of humans to distinguish different levels of gearlever load. A test rig with a forward-backward moving gearshift lever was constructed using the typical interior dimensions of European B segment automobiles. The rig used a system of weights and pulleys to provide a load which could be varied in steps of 1%. Four reference loads were chosen which were considered representative of automotive gearshift operation: 0.5, 1.0, 2.0 and 5.0 kg. Twenty subjects took part in the study. Using a variation on the psychophysical method of limits, the subjects were asked to respond whether a test load was heavier or lighter than a reference load. The Weber Fraction was found to decrease monotonically from a value of 0.036 for the 0.5 kg reference load to a value of 0.029 at the 5.0 kg reference load. The average value across all reference loads was 0.032. Measurements of the gearshift force made by means of a knob containing a load cell suggested that the variation in the measured Weber Fraction might be attributable to the time behaviour of the force exchanged between the human subject and the control surface

Communications Biophysics

Contains reports on two research projects.National Science Foundation (Grant G-16526)National Institutes of Health (Grant MH-04737-03)National Aeronautics and Space Administration (Grant NsG-496

A National Research Agenda for Virtual Reality: Report by the National Research Council Committee on VR R&D

In 1992, at the request of a consortium of federal agencies, the National Research Council established a committee to "recommand a national research and development agenda in the area of virtual reality" to set U.S. government R&D funding priorities for virtual reality (VR) for the next decade...

Communications Biophysics

Contains reports on two research projects.National Institutes of Health (Grant 1 PO1 GM-14940-02)Joint Services Electronics Programs (U. S. Army, U. S. Navy, and U. S. Air Force) under Contract DA 28-043-AMC-02536(E

Síntesis del Panel sobre Educación de postgrado, educación continuada y educación a distancia

El Dr. Aníbal Franco, decano de la Facultad de Ciencias Veterinarias, UBA, se refirió a un proyecto de formación postgrado en ciencias veterinarias, en el cooperan las ocho facultades argentinas. El Dr. Alberto Dibbern explicó el sistema de educación postgrado a distancia, de la Facultad de Ciencias Veterinarias de la UN La Plata, primer intento de facilitar a los miembros de una profesión dispersa el acceso a los adelantos en su profesión. La Dra.Lucrecia L. de Craig, Secretaria de Postgrado de la Facultad de Ciencias Veterinarias de la Universidad de Buenos Aires expuso la filosofía y el estado actual de la formación para el Doctorado de la Universidad de Buenos Aires en la Facultad de Ciencias Veterinarias que cuenta, actualmente, con 36 doctorados.Panel: Educación formal de postgrado, educación continuada y educación a distanciaAcademia Nacional de Agronomía y Veterinaria (ANAV

Síntesis del Panel sobre Educación de postgrado, educación continuada y educación a distancia

El Dr. Aníbal Franco, decano de la Facultad de Ciencias Veterinarias, UBA, se refirió a un proyecto de formación postgrado en ciencias veterinarias, en el cooperan las ocho facultades argentinas. El Dr. Alberto Dibbern explicó el sistema de educación postgrado a distancia, de la Facultad de Ciencias Veterinarias de la UN La Plata, primer intento de facilitar a los miembros de una profesión dispersa el acceso a los adelantos en su profesión. La Dra.Lucrecia L. de Craig, Secretaria de Postgrado de la Facultad de Ciencias Veterinarias de la Universidad de Buenos Aires expuso la filosofía y el estado actual de la formación para el Doctorado de la Universidad de Buenos Aires en la Facultad de Ciencias Veterinarias que cuenta, actualmente, con 36 doctorados.Panel: Educación formal de postgrado, educación continuada y educación a distanciaAcademia Nacional de Agronomía y Veterinaria (ANAV

Human Machine Interfaces for Teleoperators and Virtual Environments

In Mar. 1990, a meeting organized around the general theme of teleoperation research into virtual environment display technology was conducted. This is a collection of conference-related fragments that will give a glimpse of the potential of the following fields and how they interplay: sensorimotor performance; human-machine interfaces; teleoperation; virtual environments; performance measurement and evaluation methods; and design principles and predictive models

Manual discrimination of force

Optimal design of human-machine interfaces for teleoperators and virtual-environment systems which involve the tactual and kinesthetic modalities requires knowledge of the human's resolving power in these modalities. The resolution of the interface should be appropriately matched to that of the human operator. We report some preliminary results on the ability of the human hand to distinguish small differences in force under a variety of conditions. Experiments were conducted on force discrimination with the thumb pushing an interface that exerts a constant force over the pushing distance and the index finger pressing against a fixed support. The dependence of the sensitivity index d' on force increment can be fit by a straight line through the origin and the just-noticeable difference (JND) in force can thus be described by the inverse of the slope of this line. The receiver operating characteristic (ROC) was measured by varying the a priori probabilities of the two alternatives, reference force and reference force plus an increment, in one-interval, two-alternative, forced-choice experiments. When plotted on normal deviate coordinates, the ROC's were roughly straight lines of unit slope, thus supporting the assumption of equal-variance normal distributions and the use of the conventional d' measure. The JND was roughly 6-8 percent for reference force ranging from 2.5 to 10 newtons, pushing distance from 5 to 30 mm, and initial finger-span from 45 to 125 mm. Also, the JND remained the same when the subjects were instructed to change the average speed of pushing from 23 to 153 mm/sec. The pushing was terminated by reaching either a wall or a well, and the JND's were essentially the same in both cases

Congenital toxoplasmosis: Serology, PCR, parasite isolation and molecular characterization of toxoplasma gondii

Introducción El diagnóstico de toxoplasmosis congénita (TC) en el recién nacido es muy importante porque debe recibir tratamiento siempre, sintomático o no, para evitar o aminorar las secuelas de la enfermedad. Objetivo Evaluación comparativa de los métodos disponibles en la institución para el diagnóstico de TC. Materiales y Métodos Se evaluaron métodos diagnósticos en 67 niños cuyas madres cursaron toxoplasmosis aguda durante el embarazo. Se utilizó la técnica de Sabin Feldman para IgG al nacimiento y durante el seguimiento serológico hasta el año de vida. Para determinar IgM, IgA e IgE se utilizó la técnica immunosorbent agglutination assay (ISAGA). El diagnóstico directo se realizó por reacción de polimerasa en cadena (RPC), aislamiento y caracterización molecular del parásito. Resultados La sensibilidad (S) de ISAGA IgM fue 87%, ISAGA IgA 91% y la especificidad (E) fue 100% para ambas; cuando se realizaron en conjunto, la S aumentó a 98%. La detección de IgE contribuyó al diagnóstico cuando se la detectó sólo en la sangre del neonato y no en sangre materna. Se aisló el parásito en cuatro casos de TC, uno fue genotipo II y los otros tres, genotipos “atípicos”. La S del aislamiento fue 80% y la E 100%. Conclusión Los métodos serológicos utilizados mostraron una buena eficacia diagnóstica. Un caso fue detectado sólo por el aislamiento y la caracterización molecular tiene gran valor epidemiológico.Background. Congenital toxoplasmosis diagnosis in the newborn is a very important issue due to the need for early treatment to prevent future sequels. Aim To compare available methods at the institution for the diagnosis of congenital toxoplasmosis. Material and Methods In this study we have evaluated the different diagnostic tests used in 67 congenital exposed newborns, including serological tests, PCR, parasite isolation and molecular characterization. Results The ISAGA IgM and IgA tests showed sensitivity (Se) of 87 and 91%, respectively, and specificity (Sp) of 100%. When ISAGA IgM and IgA were performed simultaneously, the Se increased to 98% and the Sp was 100%. The presence of IgE contributed to the diagnosis when it was detected in the child's serum but not in maternal blood. In four congenital infected children the parasite was isolated and genotyped: one was genotype II and the other three were “atypical” genotypes. No parasite was isolated in children without congenital toxoplasmosis. Discussion Overall, serological tests showed a good diagnostic performance although in one case they were all negative and isolation was the only tool to identify the infection. We conclude that it is essential to use all diagnostic tests in every single exposed child, including if possible, molecular characterization due to its epidemiological implication.Fil: Carral, Liliana. Hospital Aleman; ArgentinaFil: Kaufer, Federico. Hospital Aleman; ArgentinaFil: Pardini, Lais Luján. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Epizootiología y Salud Pública. Laboratorio de Inmunoparasitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Durlach, Ricardo. Hospital Aleman; ArgentinaFil: Moré, Gastón Andrés. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Epizootiología y Salud Pública. Laboratorio de Inmunoparasitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Venturini, María C.. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Epizootiología y Salud Pública. Laboratorio de Inmunoparasitología; ArgentinaFil: Freuler, Cristina. Hospital Aleman; Argentin

Low-Level Information and High-Level Perception: The Case of Speech in Noise

Auditory information is processed in a fine-to-crude hierarchical scheme, from low-level acoustic information to high-level abstract representations, such as phonological labels. We now ask whether fine acoustic information, which is not retained at high levels, can still be used to extract speech from noise. Previous theories suggested either full availability of low-level information or availability that is limited by task difficulty. We propose a third alternative, based on the Reverse Hierarchy Theory (RHT), originally derived to describe the relations between the processing hierarchy and visual perception. RHT asserts that only the higher levels of the hierarchy are immediately available for perception. Direct access to low-level information requires specific conditions, and can be achieved only at the cost of concurrent comprehension. We tested the predictions of these three views in a series of experiments in which we measured the benefits from utilizing low-level binaural information for speech perception, and compared it to that predicted from a model of the early auditory system. Only auditory RHT could account for the full pattern of the results, suggesting that similar defaults and tradeoffs underlie the relations between hierarchical processing and perception in the visual and auditory modalities