57 research outputs found

    On effect of precession-induced flows in the liquid core for early Earth's history

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    International audienceSecondary and tertiary flow patterns seen in experiments simulating flow in the Earth's liquid core induced by luni-solar precession of the solid mantle (Vanyo et al., 1995) hint at the development of non-axisymmetric columnar periodic structures. A simple interpretation of the structure formation is presented in a hydrodynamic approach. It is suggested that if similar flow patterns can occur in the Earth's liquid core enclosed into precessing and rotating mantle then kinematic of the flows may be regarded as a possible geodynamo mechanism for early Earth's history (before the solid core formation)

    Dispersive changes in magnetic background noise polarization at 0.1 to 6Hz during sunset and sunrise at L=1.3

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    Polarization properties of the magnetic background noise (MBN) and the spectral resonance structure (SRS) of the ionospheric Alfvén resonator (IAR) below the first Schumann resonance but above 0.1 Hz are measured by a sensitive pulsation magnetometer at the island of Crete (<i>L</i>=1.3) and analyzed using the existing SRS theory by Belyaev et al. (1989b). The focus of the paper is on the systematic changes in the MBN and SRS properties associated with the transition from a sunlit to a dark ionosphere (sunset) and vice versa (sunrise). We are able to pinpoint in observations an E-region and F-region terminator effect and to simulate it by means of a simple ionosphere model, implying the formalism given by Belyaev et al. (1989b). The E-region terminator effect is associated with an apparent control for the SRS presence or absence with no clear frequency dispersion in polarization properties, whereas the F-region terminator effect exhibits strong frequency dispersion, especially in the low frequency range. This yields a change in the ellipticity of MBN, starting as early as 2 to 3h ahead of the "zero-line" of the terminator. In a 24h presentation of the ellipticity versus frequency and time, the sunrise/sunset effect produces a sharp, dispersive boundary between night and day (day and night). Only inside this boundary, during the night hours, is SRS observed, at times accompanied by a large quasi-periodic long period modulation in the azimuthal angle of the major axis of the polarization ellipse. Attention is also paid to peculiarities in the low frequency range (~0.1Hz), where especially large changes in the polarization properties occur in association with the passage of the terminator. The F-region effect is very distinct and well reproduced by our simple model. Changes in the azimuth associated with the E-region terminator effect are of the order of 20&deg

    Ion-cyclotron turbulence and diagonal double layers in a magnetospheric plasma

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    A survey of current concepts regarding electrostatic ion-cyclotron turbulence (theory and experiment), and regarding inclined double potential layers in the magnetospheric plasma is presented. Anomalous resistance governed by electrostatic ion-cyclotron turbulence, and one-dimensional and two-dimensional models of double electrostatic layers in the magnetospheric plasma are examined

    Food Leftover Practices among Consumers in Selected Countries in Europe, South and North America

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    Citation: Koppel, K., Higa, F., Godwin, S., Gutierrez, N., Shalimov, R., Cardinal, P., . . . Chambers, E. (2016). Food Leftover Practices among Consumers in Selected Countries in Europe, South and North America. Foods, 5(3), 14. doi:10.3390/foods5030066Foodborne illnesses may be related to many food production factors with home practices of consumers playing an important role in food safety. Consumer behavior for handling food leftovers has been studied, however little work on comparisons among countries has been published. The objective of this study was to investigate home food leftover practices of people from North American, South American, and European countries. Surveys were conducted with approximately 100 or more consumers in Argentina, Colombia, the United States, Estonia, Italy, Russia, and Spain. The participants responded to questions related to the length of time different types of food leftovers; such as meat, fresh salads, or restaurant dishes would be kept refrigerated or would be left at room temperature before refrigeration. Researchers also investigated how consumers would determine if the food was still safe for consumption. Potentially risky behaviors were observed in all seven countries. For instance, 55.8% of Estonians, 25% of Russians and 25.8% of Argentinean participants left food out at room temperature for several hours before storing in the refrigerator. Furthermore, 25%-29% of Colombian, Estonian, and Spanish consumers would look, smell, and taste leftovers to determine its probable safety. Correct handling of leftovers is an important aspect of consumer food safety. Although the surveys cannot be representative of all consumers in each country, they do provide an initial overview of comparative practices for handling leftovers among different countries. This provides government and educators with information on potential universal and unique consumer food safety issues related to handling leftover foods among various countries

    On the Precession Driven Geodynamo

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