7,401 research outputs found

    Techniques for obtaining regional radiation budgets from satellite radiometer observations, phase 4 and phase 5

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    A scheme was developed which divides the earth-atmosphere system into 2060 elemental areas. The regions previously described are defined in terms of these elemental areas which are fixed in size and position as the satellite moves. One method, termed the instantaneous technique, yields values of the radiant emittance (We) and the radiant reflectance (Wr) which the regions have during the time interval of a single satellite pass. The number of observations matches the number of regions under study and a unique solution is obtained using matrix inversion. The other method (termed the best fit technique), yields time averages of We and Wr for large time intervals (e.g., months, seasons). The number of observations in this technique is much greater than the number of regions considered, and an approximate solution is obtained by the method of least squares

    Techniques for computing regional radiant emittances of the earth-atmosphere system from observations by wide-angle satellite radiometers, phase 3

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    Radiometers on earth orbiting satellites measure the exchange of radiant energy between the earth-atmosphere (E-A) system and space at observation points in space external to the E-A system. Observations by wideangle, spherical and flat radiometers are analyzed and interpreted with regard to the general problem of the earth energy budget (EEB) and to the problem of determining the energy budget of regions smaller than the field of view (FOV) of these radiometers

    Calculation of disease dynamics in a population of households

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    Early mathematical representations of infectious disease dynamics assumed a single, large, homogeneously mixing population. Over the past decade there has been growing interest in models consisting of multiple smaller subpopulations (households, workplaces, schools, communities), with the natural assumption of strong homogeneous mixing within each subpopulation, and weaker transmission between subpopulations. Here we consider a model of SIRS (susceptible-infectious-recovered-suscep​tible) infection dynamics in a very large (assumed infinite) population of households, with the simplifying assumption that each household is of the same size (although all methods may be extended to a population with a heterogeneous distribution of household sizes). For this households model we present efficient methods for studying several quantities of epidemiological interest: (i) the threshold for invasion; (ii) the early growth rate; (iii) the household offspring distribution; (iv) the endemic prevalence of infection; and (v) the transient dynamics of the process. We utilize these methods to explore a wide region of parameter space appropriate for human infectious diseases. We then extend these results to consider the effects of more realistic gamma-distributed infectious periods. We discuss how all these results differ from standard homogeneous-mixing models and assess the implications for the invasion, transmission and persistence of infection. The computational efficiency of the methodology presented here will hopefully aid in the parameterisation of structured models and in the evaluation of appropriate responses for future disease outbreaks

    Contributions to planetary meteorology Final report

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    Atmospheric circulation and climatology of Venus and Mar

    The synthesis of 15 mu infrared horizon radiance profiles from meteorological data inputs

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    Computational computer program for modeling infrared horizon radiance profile using pressure and temperature profile input

    Hydrodynamic and Aerodynamic Tests of Models of Floats for Single-float Seaplanes NACA Models 41-D, 41-E, 61-A, 73, and 73-A

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    Tests were made in the NACA tank and in the NACA 7 by 10 foot wind tunnel on two models of transverse step floats and three models of pointed step floats considered to be suitable for use with single float seaplanes. The object of the program was the reduction of water resistance and spray of single float seaplanes without reducing the angle of dead rise believed to be necessary for the satisfactory absorption of the shock loads. The results indicated that all the models have less resistance and spray than the model of the Mark V float and that the pointed step floats are somewhat superior to the transverse step floats in these respects. Models 41-D, 61-A, and 73 were tested by the general method over a wide range of loads and speeds. The results are presented in the form of curves and charts for use in design calculations

    Steady-state solution to the conduction problem of a spherical balloon radiometer, phases 1 and 2

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    A satellite system proposed for observing the earth's radiation balance employing spherical balloon radiometers is investigated. In the steady-state condition of radiative equilibrium, the magnitudes of absorbed external irradiances are sensed by internal radiometers mounted on the skin of each balloon. The temperatures of the radiometers are monitored as a measure of the balloons' internal irradiances (equal to absorbed external irradiances) and telemetered to earth. The effect of the magnitude of irradiant sources, balloon thickness, and thermal conductivity on the conduction of heat is assessed mathematically in order to determine its impact on measurement accuracy. Results indicate that observations are acceptable during daytime and nighttime modes of operation

    EFFECTS OF BACKWARD WALKING AS A MODALITY FOR LOW BACK PAIN REDUCTION IN ATHLETES

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    The therapeutic effectiveness of backward walking for treatment of low back pain (LBP) was examined among athletes experiencing LBP and healthy non-athletes. All participants were pre-tested walking backward, performed 10-15 mins of backward walking three days/week for three weeks and were post-tested. Low back sagittal and coronal plane range of motion, shock attenuation (SA), stride length (SL), stride rate (SR), velocity and LBP were evaluated (α=0.05). All variables were significantly different between groups, excluding SA. Velocity, SL and SR were significantly different pre vs post. Owing to the clinical nature of this study, single-subject analyses were performed and identified unique individual responses to the intervention. Results suggest that backward walking may assist some athletes presenting with LBP

    Yes, subjective norms are important, but let's not lose sight of cultural differences

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    The study of social norms has great potential to broaden our understanding of the ways in which cultures are created and maintained. To maximise the benefit of this perspective, it is important to sample cultures widely and to include contexts in which norms are injunctiv
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