Cardiovascular risk factors and hearing loss among adults in a tertiary center of Northwestern Nigeria.

Objective: To assess the effect of cardiovascular risk factors on hearing impairment.

Methods: This was a cross sectional study conducted in Usmanu Danfodiyo University Teaching Hospital, Sokoto. A pretested questionnaire was used to obtain information about the biodata and medical history of participants after which, they were examined and had their hearing thresholds measured.

Radial distance determination in the rat vibrissal system and the effects of Weber's law.

Rats rhythmically tap and brush their vibrissae (whiskers) against objects to tactually explore the environment. To extract a complex feature such as the contour of an object, the rat must at least implicitly estimate radial object distance, that is, the distance from the base of the vibrissa to the point of object contact. Radial object distance cannot be directly measured, however, because there are no mechanoreceptors along the vibrissa.

The morphology of the rat vibrissal array: a model for quantifying spatiotemporal patterns of whisker-object contact.

In all sensory modalities, the data acquired by the nervous system is shaped by the biomechanics, material properties, and the morphology of the peripheral sensory organs. The rat vibrissal (whisker) system is one of the premier models in neuroscience to study the relationship between physical embodiment of the sensor array and the neural circuits underlying perception. To date, however, the three-dimensional morphology of the vibrissal array has not been characterized.

Biomechanical models for radial distance determination by the rat vibrissal system.

Rats use active, rhythmic movements of their whiskers to acquire tactile information about three-dimensional object features. There are no receptors along the length of the whisker; therefore all tactile information must be mechanically transduced back to receptors at the whisker base. This raises the question: how might the rat determine the radial contact position of an object along the whisker? We developed two complementary biomechanical models that show that the rat could determine radial object distance by monitoring the rate of change of moment (or equivalently, the rate of change of curvature) at the whisker base.

Biomechanics: robotic whiskers used to sense features.

Whiskers mimicking those of seals or rats might be useful for underwater tracking or tactile exploration. Several species of terrestrial and marine mammals with whiskers (vibrissae) use them to sense and navigate in their environment--for example, rats use their whiskers to discern the features of objects, and seals rely on theirs to track the hydrodynamic trails of their prey. Here we show that the bending moment--sometimes referred to as torque--at the whisker base can be used to generate three-dimensional spatial representations of the environment, and we use this principle to construct robotic whisker arrays that extract precise information about object shape and fluid flow.