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 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.

scholarly journals The Literary World of the North African Taghrība

2019 ◽  
Vol 4 (2) ◽  
pp. 188-214
Author(s):  
Karima Laachir
Keyword(s):  
Oral Tradition ◽  
World Literature ◽  
World System ◽  
Interesting Case ◽  
North African ◽  
Literary Field ◽  
The North ◽  
Shared Set ◽  
Literary Systems

Abstract The novels by North African novelists Waciny Laredj, Majid Toubia and Abdelrahim Lahbibi that refashioned the traditional Arabic genre of the taghrība inspired by the medieval epic of Taghrība of Banū Hilāl, still a living oral tradition in the region, offer an interesting case study of location in world literature. They circulate both within national (Algerian, Egyptian and Moroccan) literary systems and the pan-Arab literary field while maintaining a distinct aesthetic and political locality. In these novels, the literary life of the North African taghrība takes forms and meanings that are geographically and historically located, and that are shaped by the positionality of the authors. This paper intervenes in the discussion on location in world literature from the perspective of Arabic novelistic traditions by showing that the pan-Arabic literary field itself is far from homogenous but is marked by a diversity of narrative styles and techniques that can be both local/localised and transregional at the same time. Therefore, we need to shift our understanding of world literature beyond macro-models of “world-system” that assume a universally-shared set of literary values and tastes.

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 Les fonctions internes de la détente dans les systèmes politiques du triangle euro-arabo-africain : l’image oubliée de l’interdépendance Nord-Sud

2005 ◽  
Vol 11 (1) ◽  
pp. 65-95
Author(s):  
Abdelhai Laabi
Keyword(s):  
International Relations ◽  
International System ◽  
Human Life ◽  
Economic Problem ◽  
World Politics ◽  
Common Interest ◽  
Political Systems ◽  
The North ◽  
Starting Point ◽  
East West

This study deals with two increasingly important aspects of international relations : first, the interpretation of the North-South dynamic of the international System and second, the significance of détente in the Euro-Arabo-African mini-triangle. In his discussion of the first problematic, the author suggests it would be useful to take an interdependence approach towards the analysis of North-South relations, implying that the international system is hexagonal as regards both structure and process and that non-alignment is becoming a sixth pole of influence in the system. More specifically, and taking as a starting point the « depolarization » of the détente process, the author argues that the security objectives of the West European, Arab and African political Systems are in fact interdependent. This interdependence is to be found above all in their interest in diluting the East-West conflict and instituting a policy of détente, the purpose of which is all the more significant for being internal - i.e. the stabilization, legitimization and integration of these political Systems. Since the effects of such a policy will be felt only gradually, these countries find they have a common interest in a complementary strategy whereby the East-West conflict is segmented and intersected by the North-South conflict (intra-alliance, even). The aim of the study is to show that, in the theory of international relations, greater attention should be paid to the motivations and strategies of actors in the South and their impact on the international system in the economic problem areas as well as the political and strategic ones. Because the properties of political reality differ from those of physical reality, the properties of political regularities also differ from those of physical regularises. The regularities we discover are soft. They are soft because they are outcomes of processes that exhibit plastic rather than cast-iron control. They are imbedded in history and involve recurrent « passings-through » of large numbers of human memories, learning processes, human goal seeking impulses, and choices among alternatives. They decay quickly because of the memory, creative searching, and learning that underlie them. Indeed social science itself may contribute to this decay, since learning increasingly include not only learning from experience, but from scientific research itself. Gabriel A. ALMOND et Stephan J. GENCO, « Clouds, Clocks, and the Study of Politics », World Politics, vol. XXIX, n° 4, juillet 1977, pp. 493-494. Ithas become a platitude that the whole world is now interdependent... Yet what a tremendous platitude it is /... If this platitude is unalterably true, its implications must profoundly affect the conditions of human life for the future ; it must transform all our thinking about social organization ; it must modify all our programmes and policies. Clearly we ought to be thinking seriously about it, and asking ourselves what it involves. A. MuiR, The Interdependent World and lts Problems, Boston, Houghton, Mifflin, 1973, p. 1.

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 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.

scholarly journals Maintenance of the Midtropospheric North African Summer Circulation: Saharan High and African Easterly Jet

2005 ◽  
Vol 18 (15) ◽  
pp. 2943-2962 ◽  
Author(s):  
Tsing-Chang Chen
Keyword(s):  
Lower Troposphere ◽  
Monsoon Circulation ◽  
North African ◽  
Summer Circulation ◽  
African Easterly Jet ◽  
Differential Heating ◽  
The North ◽  
Budget Analysis ◽  
Eastern North Atlantic ◽  
East West

Abstract The conspicuous feature of the midtropospheric North African summer circulation is the Saharan high surrounded on its southern rim by the African easterly jet (AEJ). Like a major monsoon circulation, the Saharan high is juxtaposed with the North African divergent center to the east and the eastern Atlantic convergent center to the west. Different from a major monsoon circulation, these pronounced midtropospheric circulation components are overlaid by the western part of the Tibetan high. Because of the unique roles played by the Saharan high and the African easterly jet in the North African summer circulation, an effort is made to explore maintenance mechanisms of these two midtropospheric circulation elements. Major findings of this effort are summarized as follows:In terms of the velocity potential maintenance equation, it is shown that the North African divergent center over the Chad–Sudan region is maintained by the vertical differential heating established by the Saharan thermal-low heating in the lower troposphere and the Saharan radiative cooling in the upper troposphere.The Saharan high is spatially in quadrature with the North African divergent center. It is inferred from the streamfunction budget analysis that the Saharan high is maintained by the east–west circulation, which is formed by the east–west differential heating between the Saharan thermal-low heating and the eastern North Atlantic cooling. This inference is further substantiated by forced barotropic model simulations.The AEJ around the tropical periphery of the Saharan high is almost perpendicular to the equatorward divergent northerlies spilling out of the North African divergent center. The energetic interaction between divergent and rotational flows reveals that this jet is maintained by the Coriolis acceleration associated with these divergent winds. These findings not only reveal the maintenance mechanism of the Saharan high and the associated AEJ, but also facilitate the search for answers to some problems of the North African summer weather/climate system.

Slavery, Human Rights and Visas

2016 ◽  
Vol 33 (3) ◽  
pp. 251-274
Author(s):  
Tomas Sundnes Drønen
Keyword(s):  
Human Rights ◽  
Religious Activities ◽  
North African ◽  
Christian Mission ◽  
The North ◽  
Derechos Humanos ◽  
Colonial Archives ◽  
French Colonial ◽  
Local Traditions

A case study of yet unpublished material from the French colonial archives shows that the administration carefully watched the work of Christian missionaries in Cameroon. This surveillance stemmed from the administration’s fear of local rebellion due to the missionaries’ influence. In the North, the fear was that Christian mission would provoke the previously militarily powerful Fulbe to a rebellion similar to those the French had experienced in their North African colonies. The Norwegian missionaries took an active stance against local slavery, and visa applications for nine new missionaries in 1950 became the impetus for intensive surveillance from the French administration. The visa struggle and the struggle over domestic slavery also show that the administration had established a political culture that only reluctantly gave priority to serious human rights issues over respect for local traditions, and that they had established a regime of strict control over religious activities. 在法国殖民地的存档里一份未发表的档案中显示，政府小心地观察在卡麦隆的基督教宣教士的工作。这种监视乃是出自对由于宣教士的影响而会产生的本地叛乱的恐惧。在北部，这种恐惧是怕基督教宣教会引发类似在法国的北非殖民地经历了的军事叛乱。挪威的宣教士们采取积极的姿态反对奴隶制，并且1950年九位宣教士的签证申请加剧了法国政局对他们的密切监视。政府对签证和本地奴隶制的挣扎，显示了其建立的懒于将严重的人权问题置于对本地传统的尊重之上的政治文化，也显示了对宗教活动严格控制的政权。 Un estudio de caso de materiales inéditos de los archivos de las colonias francesas muestra que el gobierno vigiló el trabajo de los misioneros cristianos en Camerún. Esta vigilancia por parte del gobierno se origina por temor a una rebelión local influenciada por los misioneros. En el Norte, el temor era de que la misión cristiana llevaría a los fulbe, ya militarmente poderosos, a una rebelión similar a la que los franceses habían experimentado en sus colonias del norte de África. Los misioneros noruegos tomaron una postura activa contra la esclavitud local y la solicitud de visas para nueve nuevos misioneros en 1950 fue el impulso para la vigilancia por parte de la administración francesa. Las luchas por las visas y contra la esclavitud doméstica también muestran que el gobierno sólo había establecido una cultura política que a regañadientes daba prioridad a temas importantes de derechos humanos sobre el respeto por las tradiciones locales, y que había establecido un régimen de control estricto sobre las actividades religiosas. This article is in English.

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