Rating helicopter noise

The effectiveness of the EPNL procedure in quantifying helicopter blade slap and tail rotor noise heard on approach some distance from the flyover position is addressed. Alternative methods of rating helicopter noise are reviewed including correction procedures to the EPNL concept which account for blade slap and tail rotor noise. The impact of the use of such corrections is examined

On accounting for problems demonstrated by children with SLI in the interpretation and production of passive construction

No abstract available

Tsumeb: Zincolivenite and the Adamite-Olivenite Series

Tsumeb is one of the world’s premier localities for arsenate (and arsenite) minerals. At least eighty-four species containing the arsenate (or arsenite) anion groups have been confirmed from Tsumeb, which is the type locality for forty-two of them

On the origin of high m magnetospheric waves

A survey of Advanced Rio-Imaging Experiment in Scandinavia data reveals evidence for a previously overlooked generation mechanism of high azimuthal wave number magnetospheric waves. Here we present observations of pulsating cosmic noise absorption with azimuthal wave numbers as high as 380, suggestive of precipitation modulation by magnetospheric waves. Dispersion relations of the small-scale precipitation pulsations are indicative of the proposed origin. Previous studies of magnetospheric waves, together with data from the Charge And Mass Magnetospheric Ion Composition Experiment (Magnetospheric Ion Composition Sensor) instrument aboard the Polar spacecraft, provide support for the theory

The hydromagnetic stability of the magnetospheric boundary, Planet

Abstract-The hydromagnetic Kelvin-Helmholtz stability problem is studied for an infinite plane interface between compressible infinitely conducting fluids. The critical value of the relative streaming velocity for stability is studied by use of the equations for marginal stability without making the simplifying physical assumptions used by previous authors. In application to the magnetosphere boundary we find we can make some predictions without too precise a knowledge of all the parameters involved. At middle and low latitudes the first growing modes propagate across the Earth's field with a very low phase velocity and wave fronts closely aligned to meridian planes. The modes tend to exhibit circular polarisation in a plane almost perpendicular to the Earth's field. This behaviour should also occur at high latitudes when the magnetosheath field is closely aligned to he Earth's field

Comparison of Two Detailed Models of Aedes aegypti Population Dynamics

The success of control programs for mosquito-­borne diseases can be enhanced by crucial information provided by models of the mosquito populations. Models, however, can differ in their structure, complexity, and biological assumptions, and these differences impact their predictions. Unfortunately, it is typically difficult to determine why two complex models make different predictions because we lack structured side-­by-­side comparisons of models using comparable parameterization. Here, we present a detailed comparison of two complex, spatially explicit, stochastic models of the population dynamics of Aedes aegypti, the main vector of dengue, yellow fever, chikungunya, and Zika viruses. Both models describe the mosquito?s biological and ecological characteristics, but differ in complexity and specific assumptions. We compare the predictions of these models in two selected climatic settings: a tropical and weakly seasonal climate in Iquitos, Peru, and a temperate and strongly seasonal climate in Buenos Aires, Argentina. Both models were calibrated to operate at identical average densities in unperturbedconditions in both settings, by adjusting parameters regulating densities in each model (number of larval development sites and amount of nutritional resources). We show that the models differ in their sensitivityto environmental conditions (temperature and rainfall) and trace differences to specific model assumptions.Temporal dynamics of the Ae. aegypti populations predicted by the two models differ more markedly under strongly seasonal Buenos Aires conditions. We use both models to simulate killing of larvae and/or adults with insecticides in selected areas. We show that predictions of population recovery by the models differ substantially, an effect likely related to model assumptions regarding larval development and (director delayed) density dependence. Our methodical comparison provides important guidance for model improvement by identifying key areas of Ae. aegypti ecology that substantially affect model predictions, and revealing the impact of model assumptions on population dynamics predictions in unperturbed and perturbed conditions.Fil: Legros, Mathieu. University of North Carolina; Estados UnidosFil: Otero, Marcelo Javier. Universidad de Buenos Aires; ArgentinaFil: Romeo Aznar, Victoria Teresa. Universidad de Buenos Aires; ArgentinaFil: Solari, Hernan Gustavo. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Gould, Fred. National Institutes of Health; Estados UnidosFil: Lloyd, Alun L.. National Institutes of Health; Estados Unido