Wood Ducks breeding along the North Saskatchewan River near Fort Carlton

SummaryRecently, there has been a proliferation of international agreements imposing minimum standards on states in respect of their treatment of foreign investors and allowing investors to initiate dispute settlement proceedings where a state violates these standards. Of greatest significance to Canada is Chapter 11 of the North American Free Trade Agreement, which provides both standards for state behaviour and the right to initiate binding arbitration. Since 1996, four cases have been brought under Chapter 11. This note describes the Chapter 11 process and suggests some of the issues that may arise as it is increasingly resorted to by investors.

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Long-term Cyclic Variations of Prominences, Green and Red Coronae over Solar Cycles

International Astronomical Union Colloquium ◽

10.1017/s0252921100064496 ◽

2000 ◽

Vol 179 ◽

pp. 201-204

Author(s):

Vojtech Rušin ◽

Milan Minarovjech ◽

Milan Rybanský

Keyword(s):

Emission Lines ◽

High Latitudes ◽

Green Line ◽

Solar Cycles ◽

The South ◽

Coronal Emission ◽

Local Maxima ◽

The North ◽

Cyclic Variations

AbstractLong-term cyclic variations in the distribution of prominences and intensities of green (530.3 nm) and red (637.4 nm) coronal emission lines over solar cycles 18–23 are presented. Polar prominence branches will reach the poles at different epochs in cycle 23: the north branch at the beginning in 2002 and the south branch a year later (2003), respectively. The local maxima of intensities in the green line show both poleward- and equatorward-migrating branches. The poleward branches will reach the poles around cycle maxima like prominences, while the equatorward branches show a duration of 18 years and will end in cycle minima (2007). The red corona shows mostly equatorward branches. The possibility that these branches begin to develop at high latitudes in the preceding cycles cannot be excluded.

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Bembicosoma re-examined: a xiphosuran from the Silurian of the North Esk Inlier, Pentland Hills, Scotland

Transactions of the Royal Society of Edinburgh Earth Sciences ◽

10.1017/s0263593303000129 ◽

2003 ◽

Vol 94 (03) ◽

pp. 199

Keyword(s):

The North

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An ultrastructural study of sertoli cells in two geographically isolated populations of Aphanius dispar

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100123143 ◽

1992 ◽

Vol 50 (1) ◽

pp. 548-549

Author(s):

Taber A. Ba-Omar ◽

Philip F. Prentis

Keyword(s):

Ultrastructural Level ◽

Uranyl Acetate ◽

Freshwater Teleost ◽

Isolated Populations ◽

En Bloc ◽

The North ◽

Group A ◽

Ultrathin Sections ◽

Group B ◽

Geographically Isolated

We have recently carried out a study of spermiogenic differentiation in two geographically isolated populations of Aphanius dispar (freshwater teleost), with a view to ascertaining variation at the ultrastructural level. The sampling areas were the Jebel Al Akhdar in the north (Group A) and the Dhofar region (Group B) in the south. Specimens from each group were collected, the testes removed, fixed in Karnovsky solution, post fixed in OsO, en bloc stained with uranyl acetate and then routinely processed to Agar 100 resin, semi and ultrathin sections were prepared for study.

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SEM and TEM observations of sperm development in the testis of the freshwater fish Oreochromis mossambicus

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100157838 ◽

1990 ◽

Vol 48 (3) ◽

pp. 58-59

Author(s):

Daryl A. Cornish ◽

George L. Smit

Keyword(s):

Morphological Characteristics ◽

Oreochromis Mossambicus ◽

Breeding Cycle ◽

Limited Information ◽

North West ◽

The North ◽

Sem And Tem ◽

Sperm Development ◽

Ultrastructural Characteristics ◽

The University

Oreochromis mossambicus is currently receiving much attention as a candidater species for aquaculture programs within Southern Africa. This has stimulated interest in its breeding cycle as well as the morphological characteristics of the gonads. Limited information is available on SEM and TEM observations of the male gonads. It is known that the testis of O. mossambicus is a paired, intra-abdominal structure of the lobular type, although further details of its characteristics are not known. Current investigations have shown that spermatids reach full maturity some two months after the female becomes gravid. Throughout the year, the testes contain spermatids at various stages of development although spermiogenesis appears to be maximal during November when spawning occurs. This paper describes the morphological and ultrastructural characteristics of the testes and spermatids.Specimens of this fish were collected at Syferkuil Dam, 8 km north- west of the University of the North over a twelve month period, sacrificed and the testes excised.

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