4.3 The Euler characteristic

Subdivisions of surfaces lead to the third number used to classify surfaces, the Euler characteristic.

Definition

The Euler characteristic χ of a subdivision of a surface is

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3.3 The projective plane

We now consider one of the most important non-orientable surfaces – the projective plane (sometimes called the real projective plane). In Section 2 we introduced it as the surface obtained from a rectangle by identifying each pair of opposite edges in opposite directions, as shown in
Author(s): The Open University

Studying mammals: The opportunists
Many mammals are food specialists, with complex adaptations that gear them toward a particular food source. So how do the omnivores survive and prosper without these fancy evolutionary features? This unit examines the physiology, diet and strategies of some of these opportunistic feeders. It is the sixth unit in the ‘Studying mammals’ series. Fir
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Animal life has adapted to survive in the most unlikely and inhospitable habitats. This unit looks at the surprisingly diverse desert climates throughout the world and mammals, birds, lizards and amphibians that survive there. It splits these animals into three groups according to their strategy for survival: evaders, evaporators and endurers, then discusses how these strategies work on a biochemical and physiological level.Author(s): Creator not set

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There is increasing recognition that the reductionist mindset that is currently dominating society, rooted in unlimited economic growth unperceptive to its social and environmental impact, cannot resolve the converging environmental, social and economic crises we now face. The primary aim of this unit is to encourage the shift away from reductionist and human centred thinking towards a holistic and ecological worldview.Author(s): Creator not set

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There is increasing recognition that the reductionist mindset that is currently dominating society, rooted in unlimited economic growth unperceptive to its social and environmental impact, cannot resolve the converging environmental, social and economic crises we now face. The primary aim of this unit is to encourage the shift away from reductionist and human centred thinking towards a holistic and ecological worldview.Author(s): Creator not set

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The Space Race was an informal competition between the United States and the Soviet Union that lasted roughly from 1957 to 1975. (01:20)
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Er zijn verschillende tabbladen waarin je natuurlijke getallen kan afronden van op het tiental tot op het miljoen.

Als je het antwoord juist hebt, krijgt de cel een groene kleur.

je kan de werkbladen ook …


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In this nutrition activity (page 26 of PDF), learners consider the nutritional needs of people with specific dietary requirements, such as athletes, persons with diabetes and vegetarians, and create a full-day menu for these individuals. This activity may be used as an assessment for any unit on nutrition. This guide includes background information, setup and management tips, extensions, information about eating in space and handouts.
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