scholarly journals Observations of HF-induced instability in the auroral E region

2013 ◽  
Vol 31 (6) ◽  
pp. 1103-1108 ◽  
Author(s):  
N. M. Schlatter ◽  
N. Ivchenko ◽  
B. Gustavsson ◽  
T. Leyser ◽  
M. Rietveld
Keyword(s):  
Lower Layer ◽  
Central Feature ◽  
Ionospheric Heating ◽  
E Region ◽  
Uhf Radar

Abstract. Enhancements were observed in backscattered radar power during an ionospheric heating experiment from two distinct altitude regions in the auroral E region above Tromsø. For the experiment the EISCAT Tromsø heater was operated with O mode and X mode alternated at 4.04 MHz, close to the 3rd electron gyroharmonic. Ion-line data recorded with the EISCAT UHF radar reveal different temporal evolutions as well as different ion-line characteristics for the enhancements from the two altitude regions. The upper layer is dominated by a strong central feature, whereas the lower layer has three peaks corresponding to the central feature and the two ion lines. The altitude region of the two closely spaced (altitude separation ~ 5 km) but distinct enhancements is close to the critical altitude for the heater wave.

scholarly journals Characteristics of very large aspect angle E-region coherent echoes at 933 MHz

1997 ◽  
Vol 15 (1) ◽  
pp. 54-62 ◽  
Author(s):  
B. J. Jackel ◽  
D. R. Moorcroft ◽  
K. Schlegel
Keyword(s):  
Phase Velocity ◽  
Scattering Layer ◽  
Aspect Angle ◽  
Ion Drift ◽  
Phase Velocities ◽  
F Region ◽  
E Region ◽  
Inversion Techniques ◽  
Coherent Backscatter ◽  
Uhf Radar

Abstract. The EISCAT UHF radar system was used to study the characteristics of E-region coherent backscatter at very large magnetic aspect angles (5–11°). Data taken using 60 μs pulses during elevation scans through horizontally uniform backscatter permitted the use of inversion techniques to determine height profiles of the scattering layer. The layer was always singly peaked, with a mean height of 104 km, and mean thickness (full width at half maximum) of 10 km, both independent of aspect angle. Aspect sensitivities were also estimated, with the Sodankylä-Tromsø link observing 5 dB/degree at aspect angles near 5°, decreasing to 3 dB/degree at 10° aspect angle. Observed coherent phase velocities from all three stations were found to be roughly consistent with LOS measurements of a common E-region phase velocity vector. The E-region phase velocity had the same orientation as the F-region ion drift velocity, but was approximately 50% smaller in magnitude. Spectra were narrow with skewness of about +1 (for negative velocities), increasing slightly with aspect angle.

scholarly journals History of EISCAT – Part 4: On the German contribution to the early years of EISCAT

2016 ◽  
Vol 7 (2) ◽  
pp. 67-72
Author(s):  
Gerhard Haerendel
Keyword(s):  
Early Years ◽  
Max Planck ◽  
Ionospheric Heating ◽  
Heating Facility ◽  
Incoherent Scatter ◽  
Design And Manufacturing ◽  
History Of ◽  
Max Planck Society ◽  
Uhf Radar ◽  
German Contribution

Abstract. The decision of the Max Planck Society (MPG) to get involved in the establishment of an incoherent scatter radar in northern Europe was intimately linked to the future of the Max Planck Institute for Aeronomy (MPAe) in Katlenburg-Lindau. Delegates of the MPG played an important role in defining the rules for participation in EISCAT during the period from 1973 to 1975. The "technical" period from 1976 to 1981 was mainly devoted to the development of the UHF transmitter and the klystrons. The latter encountered great difficulties, causing substantial delays. During the same period the ionospheric heating facility was established by MPAe at Ramfjordmoen, Norway. The period following the inauguration in August 1981 saw a great number of changes in the leading personnel. In this context much attention had to be given to taxation rules. Besides continuing hardware problems with the UHF radar, severe problems arose with design and manufacturing of the VHF klystrons, requiring changes of the contractor. However, by fall of 1983 the UHF radar was able to reach the intended operational level. In 1984 important steps were made for archiving and for proper exploitation of the EISCAT data.

scholarly journals Ion and neutral temperature distributions in the E-region observed by the EISCAT Tromsø and Svalbard radars

2002 ◽  
Vol 20 (9) ◽  
pp. 1415-1427 ◽  
Author(s):  
S. Maeda ◽  
S. Nozawa ◽  
M. Sugino ◽  
H. Fujiwara ◽  
M. Suzuki
Keyword(s):  
Heat Transport ◽  
Frictional Heating ◽  
Soft Particle ◽  
Ion Temperature ◽  
Polar Cap ◽  
Low Latitude ◽  
Neutral Temperature ◽  
Defense Meteorological Satellite Program ◽  
E Region ◽  
Uhf Radar

Abstract. Simultaneous Common Program Two experiments by the EISCAT UHF radar at Tromsø and the EISCAT Svalbard radar at Longyearbyen from 00:00 to 15:00 UT on 22 September 1998 and 9 March 1999 have been utilized to investigate distributions of the ion and neutral temperatures in the E-region between 105 and 115 km. During the experiments, soft particle precipitations in the dayside cusp were observed over the Svalbard radar site by the Defense Meteorological Satellite Program (DMSP) F11 satellite. It is found that the dayside electric field in the regions of the low-latitude boundary of the polar cap and the cusp was greater and more variable than that in the auroral region. The ion temperature, parallel to the geomagnetic field at Longyearbyen, was higher than that at Tromsø during the daytime from 06:00 to 12:00 UT. The steady-state ion energy equation has been applied to derive neutral temperature under the assumption of no significant heat transport and viscous heating. The estimated neutral temperature at Longyearbyen was also higher than that at Tromsø. The ion and neutral energy budget was discussed in terms of the ion frictional heating and the Joule heating. The results indicate two possibilities: either the neutral temperature was high in the low latitude boundary of the polar cap and the cusp, or the heat transport by the polar cap neutral winds toward the dayside sector was significant.Key words. Ionosphere (auroral ionosphere; ionosphere–atmosphere interactions; polar ionosphere)

Narratives and Goals

2013 ◽  
Vol 44 (5) ◽  
pp. 303-310 ◽  
Author(s):  
Simon M. Laham ◽  
Yoshihisa Kashima
Keyword(s):  
High Achievement ◽  
Central Feature ◽  
Behavioral Task ◽  
Methodological Issues ◽  
Goal Priming ◽  
Behavioral Assimilation ◽  
Construct Accessibility

Goals are a central feature of narratives, and, thus, narratives may be particularly potent means of goal priming. Two studies examined two features of goal priming (postdelay behavioral assimilation and postfulfillment accessibility) that have been theorized to distinguish goal from semantic construct priming. Across the studies, participants were primed with high achievement, either in a narrative or nonnarrative context and then completed either a behavioral task, followed by a measure of construct accessibility, or a behavioral task after a delay. Indicative of goal priming, narrative-primed participants showed greater postdelay behavioral assimilation and less postfulfillment accessibility than those exposed to the nonnarrative prime. The implications of goal priming from narratives are discussed in relation to both theoretical and methodological issues.

Fagin's Coin of Truth: Economic Belief and Representation inOliver Twist

2014 ◽  
Vol 4 (2) ◽  
pp. 122-138
Author(s):  
Keith Clavin
Keyword(s):  
Middle Class ◽  
Economic Value ◽  
Central Feature ◽  
Secondary Markets ◽  
Jewish Culture

This essay examines Fagin from Oliver Twist as a villain whose construction joins Victorian anxieties about counterfeiting and economic deceptiveness with separate yet related concerns about the author's role in representing criminal life. Dickens triangulates Fagin's identity through cultural fears about Jewish participation within secondary markets, increased distance between purchaser and seller in an expanding credit economy, and moral ambiguities in respect to fiction-making. Read against non-literary Victorian writing about counterfeiters and crime, Fagin can be understood as a forger of identities and narratives. His ability to exploit interpersonal belief and economic value is a central feature of his villainy and one with precedent in other aspects of Victorian financial life. Dickens critiques capitalist culture by associating it with the imitative, fictional, and Jewish culture. In contrast, he aligns sincerity and truth with the middle-class, normative characters. Throughout, he marks the distinction between these two groups with comic incidence. The marginalised figures are fodder for humour and irony, while the conventional heroes are earnest.

Pharmacological study on the possible involvement of a Nrf2 -Heme oxygenase pathways in anti-cataract activity of fisetin

2020 ◽  
Vol 10 (1) ◽  
pp. 14-19
Author(s):  
Krishna Reddy BV ◽  
Avinash Kumar Reddy G ◽  
Sujitha V ◽  
Manasa A
Keyword(s):  
Oxidative Stress ◽  
Heme Oxygenase ◽  
Pharmacological Study ◽  
World Population ◽  
Central Feature ◽  
Beneficial Effects ◽  
Radical Production ◽  
Anti Oxidant ◽  
Diabetic Population ◽  
Oxidant Status

DM otherwise diabetes is now a days an epidemic with the percentage of patient population rising to almost 10% of the world population. Out of all the DM complications, cataract leads the way contributing to disabilities to about 60% of diabetic population. But the pathogenesis of DM cataract is still a half-understood area of medicine there by posing a problem in the therapy. The data that we have till now gives us enough evidence to advocate the oxidative stress has a major role for the pathogenesis of DM complications like DMnephropathy, DMneuropathy, and cardiac hypertrophy, which suggests the oxidative stress is a central feature of diabetes. In the current research, the pharmacological evaluation of Fisetin for its DM based anti-cataract property was performed. This research concentrates to estimate the possible involvement of Nrf-2 / heme oxygenase (HO)-pathway in the observed therapeutic effect, if any. The data obtained in this study also indicate that the observed beneficial effects mainly due to activation of Nrf2/HO-1 pathway. These effects probably result in increased tissue anti-oxidant status as well as decreased free radical production, which ultimately responsible for the observed beneficial effects of Fisetin against hyperglycemia-induced cataract.

Middle class ideologies: Norms and historical changes.

2017 ◽  
Author(s):  
Alex Huynh ◽  
Igor Grossmann
Keyword(s):  
Middle Class ◽  
Central Feature ◽  
Intergroup Dynamics ◽  
Social Scientists ◽  
Historical Trends ◽  
Societal Norms ◽  
Norms And Values ◽  
Behavioral Tendencies ◽  
American Society ◽  
Definition Of

Ever since social scientists became interested in understanding intergroup dynamics, the topic of the “middle class” and its distinction from other groups in society became the central feature of a theoretical and empirical research enterprise. In this overview essay we discuss the beliefs, values and behavioral tendencies attributed to American middle class beliefs, and discuss their implications for understanding class-related norms and values. We end with a reflection over the historical trends that impact societal norms and the definition of middle class in the American society.

Sign in / Sign up

Export Citation Format

Share Document