Endaural tympanoplasty without flap : a report on 34 cases

The most carefully planned and executed operation on the ear is a failure as far as the patient is concerned if the cavity collects debris and discharges for months and years afterwards. According to Mawson (1967), twenty-five per cent of radical mastoid cavities fail to heal, remain infected and discharge persistently after operation. Of 428 tympanoplasties done by Portmann (1963) between 1959 and 1962, only 75 per cent achieved perfectly dry cavities.peer-reviewe

The Mathematical description of lactation curves in dairy cattle

This review gives an overview of the mathematical modelling of lactation curves in dairy cattle. Over the last ninety years, the development of this field of study has followed the main requirements of the dairy cattle industry. Non-linear parametric functions have represented the preferred tools for modelling average curves of homogeneous groups of animals, with the main aim of predicting yields for management purposes. The increased availability of records per individual lactations and the genetic evaluation based on test day records has shifted the interest of modellers towards more flexible and general linear functions, as polynomials or splines. Thus the main interest of modelling is no longer the reconstruction of the general pattern of the phenomenon but the fitting of individual deviations from an average curve. Other specific approaches based on the modelling of the correlation structure of test day records within lactation, such as mixed linear models or principal component analysis, have been used to test the statistical significance of fixed effects in dairy experiments or to create new variables expressing main lactation curve traits. The adequacy of a model is not an absolute requisite, because it has to be assessed according to the specific purpose it is used for. Occurrence of extended lactations and of new productive and functional traits to be described and the increase of records coming from automatic milking systems likely will represent some of the future challenges for the mathematical modelling of the lactation curve in dairy cattle

Application of CFD to sonic boom near and mid flow-field prediction

A 3-D parabolized Navier-Stokes (PNS) code was used to calculate the supersonic overpressures from three different geometries at near- and mid-flow fields. Wind tunnel data is used for code validation. Comparison of the computed results with different grid refinements is shown. It is observed that a large number of grid points is needed to resolve the tail shock/expansion fan interaction. Therefore, an adaptive grid approach is employed to calculate the flow field. The agreement between the numerical results and the wind tunnel data confirms that computational fluid dynamics can be applied to the problem of sonic boom prediction

An Integrative Neurological Model for Basic Observable Human Behavior

The scientific method uncovers information from the natural world in small increments. This spurs the design of models to explain how the pieces fit together and to identify future targets of research. This is especially the case in psychology, where visualizing concepts is an advantageous practice. One all too common criticism of cognitive and behavioral models in psychology is the lack of a biological basis. This paper aims to alleviate part of this issue by integrating currently understood biological and neurological mechanisms that drive psychological phenomena into a predictive and descriptive model for basic human behavior. To accomplish this task, this paper explores numerous scientific reviews and studies regarding sensory perception, emotion, learning, and memory. This paper also features original research about decision making. Creating this model is a necessary first step for targeting possible future research and clinical practices related to human behavior

Orbiting Geophysical Observatory Attitude Control Subsystem design survey

Development history and design modifications for attitude control subsystem of OG

A method for comparing the performance of power plants for vertical flight

A new method of power plant selection for vertical flight is proposed. It can be used to determine whether the performance of a rocket design can be improved by substituting for the rocket motor a different power plant such as a ramjet. Calculations indicate that there are advantages in using the ramjet provided the power plant can be made to operate under rapid acceleration and at high altitudes

Wireless recording of the calls of Rousettus aegyptiacus and their reproduction using electrostatic transducers

Bats are capable of imaging their surroundings in great detail using echolocation. To apply similar methods to human engineering systems requires the capability to measure and recreate the signals used, and to understand the processing applied to returning echoes. In this work, the emitted and reflected echolocation signals of Rousettus aegyptiacus are recorded while the bat is in flight, using a wireless sensor mounted on the bat. The sensor is designed to replicate the acoustic gain control which bats are known to use, applying a gain to returning echoes that is dependent on the incurred time delay. Employing this technique allows emitted and reflected echolocation calls, which have a wide dynamic range, to be recorded. The recorded echoes demonstrate the complexity of environment reconstruction using echolocation. The sensor is also used to make accurate recordings of the emitted calls, and these calls are recreated in the laboratory using custom-built wideband electrostatic transducers, allied with a spectral equalization technique. This technique is further demonstrated by recreating multi-harmonic bioinspired FM chirps. The ability to record and accurately synthesize echolocation calls enables the exploitation of biological signals in human engineering systems for sonar, materials characterization and imaging