Land Grabbing and Migration in a Changing Climate

Peri-urban communal areas close to bourgeoning cities in sub-Saharan Africa are increasingly under various disaster threats, from social, environmental and institutional perspectives, as a result of urbanisation and migration. Residents of these communal areas have taken land matters into their hands, which leads to diverse land transactions. This study aimed to emphasise risks and hazards arising from land transactions taking place in a peri-urban zone of Domboshava, Zimbabwe, situated close to Harare, the capital city. Land transactions in this area include land exchanges through buying, renting and, in some cases, land grabbing. Because land transactions are on the increase in Domboshava, risks and hazards could potentially develop in social, environmental and institutional terms. Appropriate planning techniques and principles are solely needed to avoid potential disasters.

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Demonstration of Retinal Glycogen with Silver Methenamine

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100066875 ◽

1971 ◽

Vol 29 ◽

pp. 564-565

Author(s):

A. W. Sedar ◽

G. H. Bresnick

Keyword(s):

Lactic Acid ◽

Chromic Acid ◽

Periodic Acid ◽

Müller Cell ◽

External Limiting Membrane ◽

Electron Microscope Level ◽

Reactive Process ◽

Inner Limiting Membrane ◽

Muller Cell ◽

And Migration

After experimetnal damage to the retina with a variety of procedures Müller cell hypertrophy and migration occurs. According to Kuwabara and others the reactive process in these injuries is evidenced by a marked increase in amount of glycogen in the Müller cells. These cells were considered originally supporting elements with fiber processes extending throughout the retina from inner limiting membrane to external limiting membrane, but are known now to have high lactic acid dehydrogenase activity and the ability to synthesize glycogen. Since the periodic acid-chromic acid-silver methenamine technique was shown to demonstrate glycogen at the electron microscope level, it was selected to react with glycogen in the fine processes of the Müller cell that ramify among the neural elements in various layers of the retina and demarcate these cells cytologically. The Rhesus monkey was chosen as an example of a well vascularized retina and the rabbit as an example of a avascular retina to explore the possibilities of the technique.

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Structure and migration of planar defects in crystals observed in atomic scale

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100108568 ◽

1978 ◽

Vol 36 (1) ◽

pp. 284-285 ◽

Cited By ~ 1

Author(s):

H. Hashimoto ◽

Y. Sugimoto ◽

Y. Takai ◽

H. Endoh

Keyword(s):

Electron Microscope ◽

Rotation Angle ◽

Crystal Surface ◽

Electron Gun ◽

Atomic Scale ◽

Present Observation ◽

Twist Boundary ◽

Optical Magnification ◽

Zinc Crystal ◽

And Migration

As was demonstrated by the present authors that atomic structure of simple crystal can be photographed by the conventional 100 kV electron microscope adjusted at “aberration free focus (AFF)” condition. In order to operate the microscope at AFF condition effectively, highly stabilized electron beams with small energy spread and small beam divergence are necessary. In the present observation, a 120 kV electron microscope with LaB6 electron gun was used. The most of the images were taken with the direct electron optical magnification of 1.3 million times and then magnified photographically.1. Twist boundary of ZnSFig. 1 is the image of wurtzite single crystal with twist boundary grown on the surface of zinc crystal by the reaction of sulphur vapour of 1540 Torr at 500°C. Crystal surface is parallel to (00.1) plane and electron beam is incident along the axis normal to the crystal surface. In the twist boundary there is a dislocation net work between two perfect crystals with a certain rotation angle.

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