scholarly journals Two slow surface waves across North America*

1952 ◽  
Vol 42 (3) ◽  
pp. 219-228
Author(s):  
Frank Press ◽  
Maurice Ewing
Keyword(s):  
North America ◽  
Surface Waves ◽  
Crustal Structure ◽  
Large Amplitude ◽  
Orbital Motion ◽  
Initial Period ◽  
The Other ◽  
Wave Guide ◽  
Surface Shear ◽  
Slow Surface

Abstract Surface shear waves (Lg) with initial period about 1/2 to 6 sec. with sharp commencements and amplitudes larger than any conventional phase have been recorded for continental paths at distances up to 6,000 km. These waves have a group velocity of 3.51 ± .07 km/sec. and for distances greater than 20° they have reverse dispersion. For distances less than about 10° the periods shorten and Lg merges into the recognized near-earthquake phase Sg. An additional large amplitude phase in which the orbital motion of the particle is retrograde elliptical and the velocity is 3.05 ± .07 km/sec. has also been observed for continental paths. It is believed that these phases are propagated through a wave guide formed by a superficial sialic layer. The problem of explaining the propagation of these surface waves is that of finding a crustal structure which is consistent with the other data of geology and geophysics and which will provide a suitable wave guide for the new phases. A possible nature of the wave guide is described.

scholarly journals Naturalization and spread of the alien species Ozognathus cornutus (LeConte, 1859) (Coleoptera: Ptinidae: Ernobiinae) in Italy

2021 ◽  
Author(s):  
Giuliano Cerasa ◽  
Gabriella Lo Verde
Keyword(s):  
North America ◽  
Fruits And Vegetables ◽  
First Record ◽  
The Other ◽  
Ecological Role ◽  
Dried Fruits ◽  
Wood Shavings ◽  
Potential Pest ◽  
Small Wood ◽  
Natural Barrier

AbstractOzognathus cornutus (LeConte, 1859) (Coleoptera: Ptinidae: Ernobiinae), species native to North America, is a saproxylophagous species and is known to feed on decaying tissues within conspicuous galls and on vegetal decaying organic material such as dried fruits or small wood shavings and insect excrements in galleries made by other woodboring species. A few years after the first record in 2011, its naturalization in Italy is here reported. The insect was found as successor in galls of Psectrosema tamaricis (Diptera Cecidomyiidae), Plagiotrochus gallaeramulorum, Andricus multiplicatus and Synophrus politus (Hymenoptera Cynipidae). The galls seem to have played an important ecological role in speeding up the naturalization process. The lowest proportion of galls used by O. cornutus was recorded for P. tamaricis (23%), the only host belonging to Cecidomyiidae, while the percentages recorded for the other host species, all Cynipidae forming galls on oaks, were higher: 43.6%, 61.1% and 76.9% in A multiplicatus, S. politus and P. gallaeramulorum, respectively. Although O. cornutus is able to exploit other substrates like dried fruits and vegetables, for which it could represent a potential pest, it prefers to live as a successor in woody and conspicuous galls, which thus can represent a sort of natural barrier limiting the possible damages to other substrates.

scholarly journals Eurasian and North American phylogeny of Turolian hipparionine horses (Perissodactyla, Mammalia) in China

1992 ◽  
Vol 6 ◽  
pp. 305-305
Author(s):  
Mahito Watabe
Keyword(s):  
North America ◽  
North American ◽  
Northern China ◽  
Sensu Stricto ◽  
The Other ◽  
Dental Morphology ◽  
Facial Morphology ◽  
Open Land ◽  
Specialized Form ◽  
Eastern Half

The late Miocene Chinese hipparions are morphologically diversified showing similarity to both western Old World's and North American forms. Two Chinese taxa that are phylogenetically related to western Old World's forms are Hipparion fossatum (= H. forstende) from Baode (Shanxi) and H. hippidiodus from Qingyang (Gansu) and Baode. The former is related to H. mediterraneum and the latter to H. urmiense - platygenys from the Turolian localities in the western Old World. H. fossatum and H. hippidiodus are associated with the “dorcadoides” (open-land) and “mixed” faunas in northern China. Hipparion fossatum that is characterized by POF located close to the orbit co-occurs with large and morphologically specialized form, H. dermatorhinum in Baode (Loc.30). H. hippidiodus with reduced POF is discovered with smaller H. coelophyes in Loc. 43, 44 (Baode) and Loc. 115 (Gansu).The hipparions associated with the “gaudryi” (forest) fauna are characterized by well defined and small POF located far from the orbit. Those forms are: H. platyodus from Loc. 70; H. ptychodus from Loc. 73; H. tylodus from Hsi-Liang in Yushe - Wuxiang basins; and H. sefvei from Loc. 12 at Xin-an in Henan province. H. coelophyes from Baode (Loc.43 & 44) and Qingyang (Loc. 115) also show similar facial morphology to the these forms, although it has small size and shallow POF. Those forms are similar in facial and dental morphology to Hipparion sensu stricto and some species of Cormohipparion in North America.The assemblages of Chinese hipparions are composed of two groups whose members are phylogenetically similar to the forms from both western part of Eurasia and North America. The “gaudryi” fauna is considered younger than the other two on the basis of faunal analyses. The similarity in hipparionine taxonomy between northern China and North America in the latest Miocene is an evidences for possible faunal interchange(s) occurred during that period, as suggested by taxonomic analyses on carnivores and proboscideans in eastern half of Eurasia and North America.

On the mN, M Relation for Eastern North American Earthquakes

1987 ◽  
Vol 58 (4) ◽  
pp. 119-124 ◽  
Author(s):  
Gail M. Atkinson ◽  
David M. Boore
Keyword(s):  
North America ◽  
Stochastic Model ◽  
Ground Motion ◽  
Seismic Moment ◽  
The Other ◽  
Moment Magnitude ◽  
Scaling Relations ◽  
Eastern North America ◽  
Data Set ◽  
Meaningful Data

Abstract A stochastic model of ground motion has been used as a basis for comparison of data and theoretically-predicted relations between mN (commonly denoted by mbLg) and moment magnitude for eastern North America (ENA) earthquakes. mN magnitudes are recomputed for several historical ENA earthquakes, to ensure consistency of definition and provide a meaningful data set. We show that by itself the magnitude relation cannot be used as a discriminant between two specific spectral scaling relations, one with constant stress and the other with stress increasing with seismic moment, that have been proposed for ENA earthquakes.

A REVISION OF THE SYSTEMATICS OF ACALYMMA SENSU STRICTO BARBER (COLEOPTERA: CHRYSOMELIDAE) FROM NORTH AMERICA INCLUDING MEXICO

1980 ◽  
Vol 112 (S112) ◽  
pp. 1-92 ◽  
Author(s):  
D.D. Munroe ◽  
Ray F. Smith
Keyword(s):  
New Species ◽  
North America ◽  
Male Genitalia ◽  
Sensu Stricto ◽  
The Other ◽  
New Subspecies ◽  
Distribution Maps ◽  
Species Groups

AbstractThe systematics of Acalymma sensu stricto of North America including Mexico are revised. Acalymma sensu stricto is defined and distinguished from the other species groups of Acalymma. Sixteen species are discussed including four new species: A. blomorum, A. palomarense, A. invenustum, and A. luridifrons all from Mexico. Three new subspecies of A. blandulum (LeConte) are described: blandulum (LeConte) new status, nigriventre, and yucatanense. Acalymma coruscum costaricense Bechyné is placed as a synonym of A. innubum (Fabricius). Keys are presented to all species and subspecies. Habitus and male genitalia drawings are given for all species and distribution maps are given where appropriate.

scholarly journals Twin enigmatic microseismic sources in the Gulf of Guinea observed on intercontinental seismic stations

2013 ◽  
Vol 194 (1) ◽  
pp. 362-366 ◽  
Author(s):  
Yingjie Xia ◽  
Sidao Ni ◽  
Xiangfang Zeng
Keyword(s):  
North America ◽  
Temporal Variation ◽  
Crustal Structure ◽  
Source Region ◽  
Broad Band ◽  
Active Volcano ◽  
Gulf Of Guinea ◽  
Waveform Data ◽  
Seismic Stations ◽  
The Earth

Abstract Based on studies of continuous waveform data recorded on broad-band seismograph stations in Africa, Europe and North America, we report evidences for two temporally persistent and spatially localized monochromatic vibrating sources (around 0.036 and 0.038 Hz, respectively) in the Gulf of Guinea, instead of just one source (0.038 Hz or 26 s) found 50 yr ago. The location of the 0.036 Hz source is close to the Sao Tome Volcano, therefore it may be related to volcano processes. However, the 0.038 Hz source cannot be explained with known mechanisms, such as tectonic or oceanic processes. The most likely mechanism is volcano processes, but there is no reported active volcano in source region. Such repetitive vibration sources may provide valuable tools for detecting temporal variation of crustal structure of the Earth.

A NOTE ON THE BIOLOGY OF ANOPLIUS TENUICORNIS (TOURNIER) IN NORTH AMERICA (HYMENOPTERA: POMPILIDAE)

1987 ◽  
Vol 119 (1) ◽  
pp. 103-103
Author(s):  
S. Koponen ◽  
M.S. Wasbauer
Keyword(s):  
North America ◽  
The Other ◽  
Biological Information ◽  
Broad Distribution ◽  
Widespread Occurrence ◽  
Rotten Wood ◽  
Holarctic Species

Anoplius tenuicornis (Tournier) is a holarctic species with a broad distribution both in Europe (Wolf 1967) and North America (Wasbauer and Kimsey 1985). Despite the widespread occurrence of the species, individuals are not frequently encountered, so it is not surprising that biological information on it has not been available for North America and very little for Europe. Richards and Hamm (1939) gave two fragmentary reports of some significance on A. tenuicornis in England, reported as A. piliventris (Morawitz). In one case, cocoons of the wasp were found in dead thistle stems. In the other, an old burrow of Ectemnius continuus (Fabricius) (Sphecidae) (reported as Solenius) in rotten wood contained a series of wasp cocoons and fragments of clubionid spiders, the presumed prey.

Indigenous Epistemologies of North America

Episteme ◽  
2021 ◽  
pp. 1-13
Author(s):  
Barry Allen
Keyword(s):  
North America ◽  
Traditional Ecological Knowledge ◽  
Interdisciplinary Research ◽  
The Other ◽  
Ecological Knowledge ◽  
Post Colonial ◽  
Indigenous Cultures ◽  
Indigenous Epistemologies ◽  
European Philosophy ◽  
The Difference

Abstract Indigenous cultures of North America confronted a problem of knowledge different from that of canonical European philosophy. The European problem is to identify and overcome obstacles to the perfection of knowledge as science, while the Indigenous problem is to conserve a legacy of practice fused with a territory. Complicating the difference is that one of these traditions violently colonized the other, and with colonization the Indigenous problem changes. The old problem of inter-generational stability cannot be separated from the post-colonial problem of sovereignty in the land where the knowledge makes sense. I differentiate the question of the value of knowledge (Part 1), and its content (Part 2). The qualities these epistemologies favor define what I call ceremonial knowledge, that is, knowledge that sustains a ceremonial community. The question of content considers the interdisciplinary research of Indigenous and Traditional Ecological Knowledge, as well as the issue of epistemic decolonization.

Large amplitude progressive interfacial waves

1979 ◽  
Vol 93 (3) ◽  
pp. 433-448 ◽  
Author(s):  
Judith Y. Holyer
Keyword(s):  
Free Surface ◽  
Surface Wave ◽  
Surface Waves ◽  
Large Amplitude ◽  
Phase Speed ◽  
Maximum Height ◽  
Interfacial Waves ◽  
Free Surface Waves ◽  
Lower Fluid ◽  
Over The Top

This paper contains a study of large amplitude, progressive interfacial waves moving between two infinite fluids of different densities. The highest wave has been calculated using the criterion that it has zero horizontal fluid velocity at the interface in a frame moving at the phase speed of the waves. For free surface waves this criterion is identical to the criterion due to Stokes, namely that there is a stagnation point at the crest of each wave. I t is found that as the density of the upper fluid increases relative to the density of the lower fluid the maximum height of the wave, for fixed wavelength, increases. The maximum height of a Boussinesq wave, which has the density almost the same above and below the interface, is 2·5 times the maximum height of a surface wave of the same wavelength. A wave with air over the top of it can be about 2% higher than the highest free surface wave. The point at which the limiting criterion is first satisfied moves from the crest for free surface waves to the point half-way between the crest and the trough for Boussinesq waves. The phase speed, momentum, energy and other wave properties are calculated for waves up to the highest using Padé approximants. For free surface waves and waves with air above the interface the maximum value of these properties occurs for waves which are lower than the highest. For Boussinesq waves and waves with the density of the upper fluid onetenth of the density of the lower fluid these properties each increase monotonically with the wave height.

scholarly journals Large amplitude oscillations for a class of symmetric polynomial differential systems in R³

2007 ◽  
Vol 79 (4) ◽  
pp. 563-575 ◽  
Author(s):  
Jaume Llibre ◽  
Marcelo Messias
Keyword(s):  
Large Amplitude ◽  
Symmetric Polynomial ◽  
The Other ◽  
Poincaré Compactification ◽  
Heteroclinic Loop ◽  
Differential Systems ◽  
Heteroclinic Cycles ◽  
Polynomial Differential Systems ◽  
Global Study ◽  
Straight Lines

In this paper we study a class of symmetric polynomial differential systems in R³, which has a set of parallel invariant straight lines, forming degenerate heteroclinic cycles, which have their two singular endpoints at infinity. The global study near infinity is performed using the Poincaré compactification. We prove that for all n <FONT FACE=Symbol>Î</FONT> N there is epsilonn > 0 such that for 0 < epsilon < epsilonn the system has at least n large amplitude periodic orbits bifurcating from the heteroclinic loop formed by the two invariant straight lines closest to the x-axis, one contained in the half-space y > 0 and the other in y < 0.

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