Latitudinally propagating on–off switching aurorae and associated geomagnetic pulsations: A case study of an event of February 20, 1980

1981 ◽  
Vol 59 (8) ◽  
pp. 1131-1136 ◽  
Author(s):  
T. Oguti ◽  
S. Kokubun ◽  
K. Hayashi ◽  
K. Tsuruda ◽  
S. Machida ◽  
...  
Keyword(s):  
Geomagnetic Field ◽  
Auroral Zone ◽  
Geomagnetic Pulsations ◽  
The North ◽  
Field Fluctuations ◽  
Auroral Latitude ◽  
East West

Poleward propagating on–off switching aurorae and equatorward propagating aurorae, otherwise similar, were observed simultaneously at Rabbit Lake and La Ronge, respectively, for about 40 min before dawn of Feb. 20, 1980. Rabbit Lake is a high auroral latitude site, at the northern end of the Saskatchewan chain of stations for the Pulsating Aurora Campaign, whereas La Ronge, due south of Rabbit, is almost at the southern edge of the auroral zone. The repetition periods of the on–off switching aurorae are about 6 to 13 s. The poleward propagating aurorae had well defined fronts of light which extended a few hundred kilometres or more in the east–west direction. The light fronts of the equatorward propagating aurorae, though comparable in extent, were less well defined: they were thicker and fuzzier. The poleward propagating aurorae moved with a speed ~10 km/s whereas the equatorward ones did so with a slightly greater velocity. Geomagnetic field fluctuations were concurrent with the aurorae at both sites. At Rabbit Lake, northward (southward) field changes were associated with upward (downward) changes whereas the trend is reversed at La Ronge, viz., northward (southward) changes with downward (upward) changes. These trends are consistent with a model of a periodic occurrence of two line currents, westward and eastward, the former moving poleward north of Rabbit Lake and the latter approaching La Ronge from the north.

scholarly journals Monitoring and Analysis of Dynamic Characteristics of Super High-rise Buildings using GB-RAR: A Case Study of the WGC under Construction, China

2020 ◽  
Vol 10 (3) ◽  
pp. 808 ◽  
Author(s):  
Lv Zhou ◽  
Jiming Guo ◽  
Xuelin Wen ◽  
Jun Ma ◽  
Fei Yang ◽  
...  
Keyword(s):  
Wavelet Analysis ◽  
Dynamic Characteristics ◽  
Horizontal Displacement ◽  
Dynamic Monitoring ◽  
High Rise ◽  
The North ◽  
Study Results ◽  
Under Construction ◽  
East West

Accurate dynamic characteristics of super high-rise buildings serve as a guide in their construction and operation. Ground-based real aperture radar (GB-RAR) techniques have been applied in monitoring and analyzing the dynamic characteristics of different buildings, but only few studies have utilized them to derive the dynamic characteristics of super high-rise buildings, especially those higher than 400 m and under construction. In this study, we proposed a set of technical methods for monitoring and analyzing the dynamic characteristics of super high-rise buildings based on GB-RAR and wavelet analysis. A case study was conducted on the monitoring and analysis of the dynamic characteristics of the Wuhan Greenland Center (WGC) under construction (5–7 July 2017) with a 636 m design height. Displacement time series was accurately derived through GB-RAR and wavelet analysis, and the accuracy reached the submillimeter level. The maximum horizontal displacement amplitudes at the top of the building in the north–south and east–west directions were 18.84 and 15.94 mm, respectively. The roof displacement trajectory of the WGC was clearly identified. A certain negative correlation between the temperature and displacement changes at the roof of the building was identified. Study results demonstrate that the proposed method is effective for the dynamic monitoring and analysis of super high-rise buildings with noninvasive and nondestructive characteristics.

FURTHER OBSERVATIONS OF THE HORIZONTAL MOVEMENTS OF AURORA

1960 ◽  
Vol 38 (10) ◽  
pp. 1366-1375 ◽  
Author(s):  
J. A. Kim ◽  
B. W. Currie
Keyword(s):  
Magnetic Field ◽  
Seasonal Variation ◽  
Magnetic Field Intensity ◽  
Geomagnetic Latitude ◽  
Auroral Zone ◽  
The North ◽  
Significant Seasonal Variation ◽  
Positive Correlations ◽  
The Magnetic Field ◽  
East West

A previous paper showed that systematic motions of aurora parallel and normal to the geomagnetic meridians could be deduced from successions of all-sky camera photographs. More reliable deductions which are based on a much larger number of observations, including some from a station inside the auroral zone, are reported in this paper. Both southward and northward speeds increase with geomagnetic latitude to the auroral zone where they become constant, or even decrease slightly, before continuing to increase inside the auroral zone. A seasonal variation of north–south speeds does not appear to exist. A diurnal variation of north–south speeds, dependent on geomagnetic latitude, is evident, the speeds decreasing to a minimum during the morning hours to the south of the auroral zone and increasing to a maximum during the same hours to the north of the zone. Large positive correlations exist between north–south speeds and departures of the magnetic field intensity from normal. East–west speeds either decrease or remain constant with increasing geomagnetic latitude. A significant seasonal variation of east–west speeds is not evident. Eastward speeds are at a maximum between 03 and 04 hours L.M.T., and are associated with negative magnetic bays; westward speeds, between 21 and 22 hours L.M.T., and are associated with positive magnetic bays.

The Establishment of Bulgarian–West German Diplomatic Relations within the Coordinating Framework of the Warsaw Pact

2016 ◽  
Vol 18 (3) ◽  
pp. 158-180 ◽  
Author(s):  
Jordan Baev
Keyword(s):  
Political Orientation ◽  
Complex Nature ◽  
Diplomatic Relations ◽  
Warsaw Pact ◽  
The North ◽  
Force Reduction ◽  
Major Factors ◽  
The Cold War ◽  
East West

Bulgarian–West German relations played a crucial role in Bulgarian foreign policy in Europe from the time the FRG became a leading West European political and economic power and a key member of both the North Atlantic Treaty Organization and the European Economic Community. The normalization of official relations between Bulgaria and the FRG was significantly influenced by two major factors: the policy of closer coordination and multilateral interaction within the Warsaw Pact and the somewhat slower, though increasing, process of East-West détente and security negotiations in Europe through CSCE and the Mutual and Balanced Force Reduction talks. This case study of the establishment of diplomatic relations between a powerful European state and a smaller one with opposite political orientation amid the East-West détente in the 1970s contributes to scholars’ understanding of the complex nature of international relations in Europe during the Cold War.

scholarly journals Understanding creative hubs : the agglomeration of creativity in Toronto

2021 ◽  
Author(s):  
Amanda Chen XiaoXuan
Keyword(s):  
Conceptual Framework ◽  
District Level ◽  
Institutional Level ◽  
The North ◽  
Local Resources ◽  
Functional Value ◽  
Essential Components ◽  
The City ◽  
East West

This paper conducts an unprecedented research that thoroughly defines the concept of creative hubs as an urban mechanism that emerges from the need of effectively leveraging local resources to better facilitate creative activities and ultimately improve local economics. Building a conceptual framework that articulates the three essential components (the 3Ps) of creative hubs: people, place and planning, this study further analyzes the creative-hub distribution in the city of Toronto. Using a mapping approach to illustrate how different creative hubs scatter, it is observed that there exist congregations of institutional-level and district-level creative hubs along the north-south and east-west direction respectively in the City of Toronto. Finally, a case study on Liberty Village is conducted to scrutinize how a creative hub achieve [sic] its functional value basing [sic] on its people, place, and planning policies.

Faunal specificity, endemism and paleobiogeography: the post-glacial (Hirnantian-early Rhuddanian) graptolite fauna of the North-African border of Gondwana: a case study

2009 ◽  
Vol 180 (4) ◽  
pp. 353-367 ◽  
Author(s):  
Philippe Legrand
Keyword(s):  
Water Density ◽  
North African ◽  
Specific Level ◽  
Selective Filter ◽  
The North ◽  
Starting Point ◽  
Glacial Rebound ◽  
Marine Clays ◽  
East West

Abstract Several types of stratigraphic successions are found at the top of the glacial to periglacial “Complexe terminal” forming the uppermost Ordovician of the North-African border of Gondwana. Locally, there may be a progressive transition from microconglomeratic clays (diamictites) with dropstones to more normal marine clays accompanied by the almost immediate reappearance of graptolites. Study of the graptolites has revealed a distinctive composition at the specific level, differing from contemporaneous faunal associations in adjacent regions, which consist of such classical species as “Glyptograptus” persculptus, Akidograptus ascensus, Parakidograptus acuminatus, etc. The faunal composition has long posed a chronostratigraphic problem, which has now been largely resolved, the fauna being interpreted as Hirnantian to early Rhuddanian in age. On the other hand, the clear evidence of faunal specificity poses a number of problems in the post-glacial context, namely: the disappearance of graptolites in the mid-Caradoc from these regions poses a problem as to the origin of the new specific fauna. Three hypotheses are considered, none of which is satisfactory. Most available data point to an eastern communication, although it is possible that the rejuvenation of the Mauritanides to the west “erased” all prior evidence, giving a wrong idea as to the communications which existed in the area under consideration; what mechanisms caused and maintained this isolation? The hypothesis of a wide, east-west trending depression produced by the overloading of the frontal ice sheet and its progressive disappearance concomitant with the glacial rebound is being considered; what were the effects of isolation on the morphology of graptolites and their population? The virgella and the virgula in several species are remarkably long and this could be attributed to a reduction in water density. The size of monospecific populations also attests to an adaptation to a restricted regime with sandy deposition; how can one explain why some species like N. pseudovenustus, N. inazzaouae, N. normalis brenansi and Ps. kiliani, occur also in other parts of the world? If these species occur where the classical species are absent, the opposite is even more difficult to explain, leading one to postulate the presence of a selective “filter”; how did this faunal specificity disappear progressively? The extent of the sea with Nd. africanus and Nd. fezzanensis put an end to isolation, although it respected the east-west trend. However, there was an opening to the adjacent regions corresponding to present-day Libya. To conclude, if pelagic faunas are considered to be poor paleogeographic tools, faunal specificity rather than endemism should be regarded as the starting point for further reflection. However, all faunal specificity must be fully documented and the results integrated in a framework that includes all aspects of sedimentology, tectonics and climatology. Seven new species are briefly described: Normalograptus nseirati sp. nov., Normalograptus gelidus sp. nov., Normalograptus arrikini sp. nov., Normalograptus pretilokensis sp. nov., Neodiplograptus inezzani sp. nov., Neodiplograptus incommodus sp. nov. and “Glyptograptus” saharensis sp. nov.

scholarly journals Analysis of Aeromagnetic Anomalies of the North-eastern Nigerian part of the Chad Basin

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Kehinde Ishola ◽  
Blessing Okoye ◽  
Lukumon Adeoti ◽  
Kayode Oyedele
Keyword(s):  
Geomagnetic Field ◽  
Fourier Transformation ◽  
Magnetic Anomalies ◽  
Aeromagnetic Data ◽  
The North ◽  
Spectral Technique ◽  
North Eastern ◽  
Anomaly Map ◽  
East West

An appraisal of aeromagnetic data lying between Longitudes 110 00' 25.95''E - 110 30’ 15.1”E and Latitudes 110 30’ 7.59”N – 120 05’ 45.6''N has been carried out with a view to understanding structural trends of interest as well as determination of depth to magnetic sources giving rise to magnetic anomalies in the study area. To achieve the objectives of this study, the datasets were digitized along contours, corrected for the main geomagnetic field, re-gridded, and merged to generate magnetic structural anomaly map of the area. Also, from the aeromagnetic data, we used spectral technique based on Fourier transformation to estimate depths along some selected profiles on the residual anomaly map. The results show that the most pronounced structures are observed towards the southern and central parts of the study area signifying that majority of the magnetic anomalies trend in the Northeast-Southwest while the minor ones trend East-West direction. This suggests that the study area is intensely fractured with major regional faulting systems playing important role in entrapment and exploration of natural resources as well as understanding the hydrogeologic framework of the basin. The spectral analysis shows mainly two depth magnetic sources, the deeper sources with depths in the range of 1.34 to 3.42 km while the shallow sources are observed at depths between 0.33 to 0.91 km. Aeromagnetic data analysis over the basin shows that prominent anomalies have been identified and located.

Experimental tests of the mechanism of radio emission from showers

1968 ◽  
Vol 46 (10) ◽  
pp. S230-S233 ◽  
Author(s):  
F. G. Smith ◽  
A. D. Bray ◽  
R. A. Porter ◽  
W. S. Torbitt ◽  
J. V. Jelley
Keyword(s):  
Radio Emission ◽  
Geomagnetic Field ◽  
Experimental Tests ◽  
Excess Charge ◽  
The North ◽  
Dip Angle ◽  
East West

It is expected that the geomagnetic field will separate the shower particles of opposite signs, giving radiation which shows an east–west polarization. This has been tested by using crossed dipoles, and by searching for the expected asymmetry in the north–south plane due to the dip angle of the field. No evidence for geomagnetic separation has been found, and it is concluded that the excess charge must be greater than had previously been assumed.

scholarly journals Understanding creative hubs : the agglomeration of creativity in Toronto

2021 ◽  
Author(s):  
Amanda Chen XiaoXuan
Keyword(s):  
Conceptual Framework ◽  
District Level ◽  
Institutional Level ◽  
The North ◽  
Local Resources ◽  
Functional Value ◽  
Essential Components ◽  
The City ◽  
East West

This paper conducts an unprecedented research that thoroughly defines the concept of creative hubs as an urban mechanism that emerges from the need of effectively leveraging local resources to better facilitate creative activities and ultimately improve local economics. Building a conceptual framework that articulates the three essential components (the 3Ps) of creative hubs: people, place and planning, this study further analyzes the creative-hub distribution in the city of Toronto. Using a mapping approach to illustrate how different creative hubs scatter, it is observed that there exist congregations of institutional-level and district-level creative hubs along the north-south and east-west direction respectively in the City of Toronto. Finally, a case study on Liberty Village is conducted to scrutinize how a creative hub achieve [sic] its functional value basing [sic] on its people, place, and planning policies.

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