15,731 research outputs found

    Energy Conversion Alternatives Study (ECAS), General Electric Phase 1. Volume 3: Energy conversion subsystems and components. Part 1: Bottoming cycles and materials of construction

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    Energy conversion subsystems and components were evaluated in terms of advanced energy conversion systems. Results of the bottoming cycles and materials of construction studies are presented and discussed

    Fetal heterotaxy with tricuspid atresia, pulmonary atresia, and isomerism of the right atrial appendages at 22 weeks.

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    We report the accurate prenatal diagnosis at 22 weeks gestation of right atrial isomerism in association with tricuspid atresia. Several distinctive sonographic features of isomerism of the right atrial appendages were present in this fetus: complex cardiac abnormality, ventriculoarterial discordance, juxtaposition of the aorta and the inferior vena cava to the right side, pulmonary atresia, and anomalous pulmonary venous return to the morphological right atrium. Tricuspid atresia, which is an extremely rare lesion within heterotaxy spectrum disorders, was present. Postnatal investigations confirmed all prenatally diagnosed abnormalities, with additional findings of pulmonary atresia with discontinuous pulmonary arteries and bilateral arterial ducts, asplenia, and bilateral eparterial bronchi. To our knowledge, tricuspid atresia in the setting of isomerism of the right atrial appendages has not previously been diagnosed or reported prenatally. Because of the complexity of cardiac lesions that may be present in cases of atrial isomerism, these disorders should be considered even if sonographic findings are uncommon or atypical

    Impact of Social Media on Economic Growth - Evidence from Social Media

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    This paper attempts to investigate the impact of social media on economic growth. Using information obtained from memberships to social networks, we find that social media has a negative and significant impact on economic growth. This provides evidence in favour of our hypothesis that social media increases the search costs for information and also increases the substitution effect from labour to leisure thereby producing a negative impact on growth

    Chaotic diffusion of particles with finite mass in oscillating convection flows

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    Deterministic diffusion in temporally oscillating convection is studied for particles with finite mass. The particles are assumed to obey a simple dissipative dynamical system and the particle diffusion is induced by the strange attractor. The diffusion constants are numerically calculated for convection models with free and rigid boundary conditions.Comment: 5 figure

    Using handheld pocket computers in a wireless telemedicine system

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    Objectives: To see if senior emergency nurse practitioners can provide support to inexperienced ones in a Minor Injuries Unit by using a wireless LAN system of telemedicine transmitting images to a PDA when they were on duty. In addition, whether such a system could be sufficiently accurate to make clinical diagnoses with a high level of diagnostic confidence. This would permit an overall lower grade of nurse to be employed to manage most of the cases as they arrive with a proportionate lowering of costs. Methods: The wireless LAN equipment could roam in the Minor Injuries Unit and the experienced emergency Nurse practitioners could be at home, shopping or even at a considerable distance from the centre. Thirty pictorial images of patients who had been sent to the Review Clinic were transmitted to a PDA various distances of one to sixteen miles from the centre. Two senior emergency nurse practitioners viewed the images and opined on the diagnosis, their degree of confidence in the diagnosis and their opinion of the quality of the image. Results: the images of patients were sharp, clear, and of diagnostic quality. The image quality was only uncertain, as was the level of confidence of the diagnosis if the patient was very dark skinned. Conclusions: The wireless LAN system works with a remote PDA in this clinical situation. However there are question marks over the availability of enough experienced emergency nurse practitioners to staff a service that provides senior cover for longer parts of the day and at weekends

    Monetary policy and economic activity: a postwar review

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    Monetary policy ; Financial markets ; Economic conditions

    Visible and near-ultraviolet spectroscopy at Thule AFB (76.5 N) from January 28 - February 15, 1988

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    Near-ultraviolet and visible spectrographs identical to those employed at McMurdo Station, Antarctica (77.8 S) during the austral spring seasons of 1986 and 1987 were used to study the stratosphere above Thule, Greenland (76.5 N) during early spring, 1988. Observations were carried out both at night using the direct moon as a light source, and during the day by collecting the scattered light from the zenith sky when solar zenith angles were less than about 94.5 degrees. Excellent meteorological conditions prevailed in the troposphere and stratosphere at Thule. Surface weather was extremely clear over most of the period, facilitating measurements of the direct light from the moon. The lower stratospheric arctic polar vortex was located very near Thule throughout the observing period, and temperature at the 30 mbar level were typically below -80 C above Thule, according to the National Meteorological Center daily analyses. Thus conditions were favorable for polar stratospheric cloud formation above Thule. Total column ozone abundances were about 350 to 400 Dobson units, and did not suggest a clear temporal trend over the observing period. Stratospheric nitrogen dioxide measurements were complicated by the presence of a large component of tropospheric pollution on many occasions. Stratospheric nitrogen dioxide could be identified on most days using the absorption in the scattered light from the zenith sky, which greatly enhances the stratospheric airmass while suppressing the tropospheric contribution. These measurements suggest that the total vertical column abundance of nitrogen dioxide present over Thule in February was extremely low, sometimes as low as 3 x 10 to the 14th per sq cm. The abundance of nitrogen dioxide increased systemically from about 3 x 10 to the 14th in late January to 1.0 x 10 to the 15th per sq cm in mid-February, perhaps because of photolysis of N2O5 in the upper part of the stratosphere, near 25 to 35 km

    Coherent pairing states for the Hubbard model

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    We consider the Hubbard model and its extensions on bipartite lattices. We define a dynamical group based on the η\eta-pairing operators introduced by C.N.Yang, and define coherent pairing states, which are combinations of eigenfunctions of η\eta-operators. These states permit exact calculations of numerous physical properties of the system, including energy, various fluctuations and correlation functions, including pairing ODLRO to all orders. This approach is complementary to BCS, in that these are superconducting coherent states associated with the exact model, although they are not eigenstates of the Hamiltonian.Comment: 5 pages, RevTe

    Non-Point Source Pollution Modelling: An Overview

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    The objective of this paper is to provide a critical evaluation of the data available from existing studies concerning non-point source pollution (NPS). NPS pollution is complex and difficult to detect and manage when compared with point source pollution. To tackle its risk, it is vital to have precise simulations and estimations of NPS pollutants. Different modelling techniques applied to NPS pollution were reviewed and classified as either physically-based models or empirical. The physically-based models (White box models) can be used both for long-term and daily time steps. They require initial model data as well as watershed morphological and physiographic, which makes them complex and not easy to use. Empirical models on the other hand are called black-box models or metric models and can be used for both long-term, daily time steps with minimal data requirement and requires less skill to operate. Although their results are easy to interpret, these types of models are only suitable within the boundary of a certain domain. The findings of this review will serve as a guide to water resource planners in identifying the type of NPS model they need to apply to a particular catchment for a particular problem

    Municipal Solid Waste Management in Debre Berhan City of Ethiopia

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    This paper presents an assessment of municipal solid waste generation and composition in Debre Berhan city in Ethiopia, providing an overview of the current state of municipal solid waste management, an analysis of the current problems in MSW collection, transportation, recycling and disposal, and few suggestions for improving the MSW in the coming years. Currently, waste composition in Debre Berhan is dominated by a high organic content, since the concentration of food and kitchen waste in urban solid waste makes up the highest proportion of the waste stream. The study revealed that only 25 % of the households have access to waste collection and transportation services as city municipality is under capacity to provide waste collection and transportation service.  98% of the respondents reported that recycling is not being practiced in the town. So, the potential of recycling and related activities is yet to be exploited. 75% of the urban dwellers dump the waste produce illegally and there exists no well designed dumping or landfill site, consequently urban dwellers are vulnerable to surface and groundwater pollution. Urgent and immediate improvement in building the capacities of the municipality is necessary to meet the current demand for improved municipal waste management and a number of recommendations are made aimed at improving the MSW management system. Keywords: Ethiopia, Waste Collection, Waste Disposal, Municipal Solid Waste Management
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