Auroral and associated magnetospheric phenomena at very high latitudes

1967 ◽  
Vol 7 (2-3) ◽  
pp. iii-iii
Author(s):  
C. De Jager
Keyword(s):  
High Latitudes ◽  
Very High

scholarly journals PRIMATA BESAR DI JAWA: SPESIMEN BARU GIGANTOPITHECUS DARI SEMEDO

2016 ◽  
Vol 36 (2) ◽  
pp. 141-160 ◽  
Author(s):  
Sofwan Noerwidi
Keyword(s):  
Morphometric Analysis ◽  
Research Problem ◽  
Homo Erectus ◽  
Taxonomic Position ◽  
Tropical Environment ◽  
High Latitudes ◽  
Comparison Study ◽  
Species Identity ◽  
Morphometric Characters ◽  
Very High

In 2014 there was found two "enigmatic" specimens of mandible, which named as Semedo 3417 and 3418. Both mandibles are morphologically similar but twice bigger than common primate’s jaw. In this research, we use morphology and morphometric analysis to determine the species identity and taxonomic position of those specimens. For comparison study we use some samples from Homo erectus (Java and China), Gigantopithecus (blacki and bilaspurensis), Australopithecines (robust and gracile). Based on morphology and morphometric characters on the mandible and teeth, it is concluded that Semedo specimen tends to be close to Gigantopithecus blacki. The discoveries of Gigantopithecus fossil in Java has implication on some research problem, especially regarding the adaptation pattern of this species which known only found at high latitudes environment. Furthermore this discovery has reinforced the perspective that tropical environment has a very high biodiversity, particularly on primate fossils.

Studies of Geomagnetic Conjugacy at Very High Latitudes

1998 ◽  
pp. 327-342 ◽  
Author(s):  
C. G. Maclennan ◽  
L. J. Lanzerotti ◽  
D. J. Thomson
Keyword(s):  
High Latitudes ◽  
Very High

Study of a QP/GP event at very high latitudes

1986 ◽  
Vol 91 (A1) ◽  
pp. 375 ◽  
Author(s):  
L. J. Lanzerotti ◽  
C. G. Maclennan ◽  
L. V. Medford ◽  
D. L. Carpenter
Keyword(s):  
High Latitudes ◽  
Very High

Studies on the Origin, Evolution, and Distribution of the Gramineae. V. The Subfamily Festucoideae

1973 ◽  
Vol 21 (2) ◽  
pp. 201 ◽  
Author(s):  
W Hartley
Keyword(s):  
Distribution Patterns ◽  
The United States ◽  
Evolutionary Development ◽  
High Latitudes ◽  
Strong Negative Correlation ◽  
Distribution Maps ◽  
The World ◽  
South Eastern Europe ◽  
Specific Frequency ◽  
Very High

Maps are presented showing the world distributions of the subfamily Festucoideae and the tribe Festuceae, based on data on relative specific frequency derived from about 500 widely-distributed floras and floristic lists. The maps show many points of similarity and, especially in N. America, there is a very high correlation between the numbers of species of the subfamily and tribe in regional floras. Both the Festucoideae and the Festuceae attain their highest relative specific frequency in high latitudes or at high altitudes. There is a strong negative correlation between high specific frequency and midsummer temperature in the flora of the United States, and evidence of a similar, though less marked, relationship in other regions. The effect of rainfall is not apparent in the distribution maps. Regions of high relative specific frequency of the tribes Agrostideae, Aveneae, Stipeae, and Triticeae are mapped, and discussed in relation to climate. In their geographical relationships, the tribes studied fall into two groups, viz. (1) Agrostideae, Aveneae, and Festuceae; (2) Stipeae and Triticeae. The significance of the distribution patterns is discussed in relation to the evolutionary development of the subfamily Festucoideae and its constituent tribes. The phytogeographical evidence supports the view that each tribe is monophyletic, with the exception of the Aveneae (sensu str.), which is well developed in regions of diverse climate. A strongly developed enclave of high relative specific frequency of Festuceae in part of south-eastern Europe, which shows no obvious relationship to climate, is interpreted as evidence for the occurrence of a cycle of secondary evolution of the tribe in this region.

scholarly journals Excitation thresholds of field-aligned irregularities and associated ionospheric hysteresis at very high latitudes observed using SPEAR-induced HF radar backscatter

2009 ◽  
Vol 27 (7) ◽  
pp. 2623-2631 ◽  
Author(s):  
D. M. Wright ◽  
R. S. Dhillon ◽  
T. K. Yeoman ◽  
T. R. Robinson ◽  
E. C. Thomas ◽  
...  
Keyword(s):  
Hf Radar ◽  
High Latitudes ◽  
Plasma Parameters ◽  
Power Cycle ◽  
Incoherent Scatter ◽  
Radiated Power ◽  
Induced Field ◽  
High Latitude Ionosphere ◽  
Very High ◽  
Field Aligned Irregularities

Abstract. On 10 October 2006 the SPEAR high power radar facility was operated in a power-stepping mode where both CUTLASS radars were detecting backscatter from the SPEAR-induced field-aligned irregularities (FAIs). The effective radiated power of SPEAR was varied from 1–10 MW. The aim of the experiment was to investigate the power thresholds for excitation (Pt) and collapse (Pc) of artificially-induced FAIs in the ionosphere over Svalbard. It was demonstrated that FAI could be excited by a SPEAR ERP of only 1 MW, representing only 1/30th of SPEAR's total capability, and that once created the irregularities could be maintained for even lower powers. The experiment also demonstrated that the very high latitude ionosphere exhibits hysteresis, where the down-going part of the power cycle provided a higher density of irregularities than for the equivalent part of the up-going cycle. Although this second result is similar to that observed previously by CUTLASS in conjunction with the Tromsø heater, the same is not true for the equivalent incoherent scatter measurements. The EISCAT Svalbard Radar (ESR) failed to detect any hysteresis in the plasma parameters over Svalbard in stark contract with the measurements made using the Tromsø UHF.

ULF waves at very high latitudes

2006 ◽  
pp. 137-156 ◽  
Author(s):  
M. J. Engebretson ◽  
J. L. Posch ◽  
V. A. Pilipenko ◽  
O. M. Chugunova
Keyword(s):  
Ulf Waves ◽  
High Latitudes ◽  
Very High

scholarly journals The impact of CMEs on the critical frequency of F2-layer ionosphere (foF2)

2019 ◽  
Vol 15 (S356) ◽  
pp. 400-402
Author(s):  
Alene Seyoum ◽  
Nat Gopalswamy ◽  
Melessew Nigussie ◽  
Nigusse Mezgebe
Keyword(s):  
Critical Frequency ◽  
Angular Width ◽  
High Latitudes ◽  
Solar Cycles ◽  
Middle Latitudes ◽  
Low Latitudes ◽  
Critical Frequency Fof2 ◽  
The Impact ◽  
Very High

AbstractThe ionospheric critical frequency (foF2) from ionosonde measurements at geographic high, middle, and low latitudes are analyzed with the occurrence of coronal mass ejections (CMEs) in long term variability of the solar cycles. We observed trends of monthly maximum foF2 values and monthly averaged values of CME parameters such as speed, angular width, mass, and kinetic energy with respect to time. The impact of CMEs on foF2 is very high at high latitudes and low at low latitudes. The time series for monthly maximum foF2 and monthly-averaged CME speed are moderately correlated at high and middle latitudes.

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