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1.1 Introduction

There are many environmental reasons why coal is a rather undesirable source of energy. Burning it introduces large amounts of gases into the atmosphere that harm the environment in a variety of ways, as well as other, solid waste products. Coal extraction leads to spoil heaps and mines that scar the landscape, land subsidence that affects roads and buildings, and in some cases water pollution.

With apparently so little going for it, why do we rely so much on coal to meet our energy nee
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Dragon Departs the Station
The Expedition 31 crew used the Canadarm2 robotic arm to demate the SpaceX Dragon cargo vehicle from the Earth-facing port of the station's Harmony node at 4:07 a.m. EDT on Thursday. It was released from the station's robotic arm at 5:49 a.m.
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2.6 Underground mining

Coal extraction is of course less straightforward using underground mining techniques. The associated costs are higher, and these begin with the sinking of two shafts, an 'upcast' and a 'downcast' shaft for ventilation (Figure 22). Sinking these to a depth of a kilometre may take a few years and during this time,
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Keep on learning

Study another free course

There are more than 800 courses on OpenLearn for you to
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1.12.2 Constructing discursive spaces

Finally, the notion of discursive space draws attention to the broader social practices which construct such spaces. Thus social scientists and discourse researchers have been interested in the practices of production of newspapers and the media and in the ways in which economic and technological developments construct discursive spaces. E-mail, the internet and computer-mediated communication are good examples of how changing practices produce new spaces which construct new kinds of discursi
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2.6.1 Weighing up the evidence: the full cast of suspects

Figure 36 (again adapted from the TAR) takes your thoughts on Question 11 on a stage. It gives estimates of the cumulative effect since pre-industrial times of the various climate change agents, with the contributions expressed in terms of radiative forcing. Note that the figure also includes yet another device for communicating the IPCC's confidence in a particular finding - an indication of the 'level of scientific understanding' that accompanies each estimate. This reflects the authors' su
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2.3.1 Geological mapping of coalfields

Coalfields can be divided into two categories: exposed coalfields, where the coal-bearing strata outcrop at the surface, and concealed coalfields, where they are hidden beneath younger rocks. Exposed coalfields can be defined with considerable precision by surface geological investigations; indeed geologists recording field data still represent the cheapest exploration 'tool' available to the coal industry.

In populated regions, the locations of coal outcrops are well know
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Recherches sur les bases moléculaires de la "sucrosité" des vins secs

9e matinée des Œnologues - Bordeaux

>> Goût du vin : les dernières avancées de la recherche

Jean-Christophe Barbe, Le fruit dans les vins rouges

Michael Jourdes, Tanin du bois : évolutions et perceptions sensorielles

Axel Marchal, Recherches sur les bases moléculaires de la « sucrosité » des vins secs


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3.3 Optical amplifiers

Figure 22 shows in outline one possible structure for an Erbium-doped fibre amplifier (EDFA).

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Learning outcomes

After studying this course, you should be able to:

  • explain the principles that underlie the ability of various natural phenomena to deliver solar energy

  • outline the technologies that are used to harness the power of solar energy

  • discuss the positive and negative aspects of solar energy in relation to natural and human aspects of the environment.


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4 What is a ‘nation’?

Guibernau (1996, p. 47) has defined the nation as: ‘a human group conscious of forming a community, sharing a common culture, attached to a clearly demarcated territory, having a common past and a common project for the future and claiming the right to rule itself’. So awareness, territory, history and culture, language and religion all matter. However, it is rare in the real world to find a case of a nation with a clear-cut and homogenous character in terms of this list of possibilities.
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Original Copyright © 2005 The Open University. Now made available within the Creative Commons framework under the CC Attribution – Non-commercial licence (see http://creativecommons.org/licenses/by

5.4 Identifying sources

So what material do you have available to you?

  • Your materials are likely to be your first sources of information.

  • Any guidance notes you may have been given will sometimes tell you exactly which sections you need to look at. But don't forget that your course materials encompass more than just these texts.

  • Make use of any handouts you've been given.

  • Your own notes of what you have been reading or watching; fr
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2.3 Movie 2 - Red Spot Movie

Red Spot Movie

View document182.1KB video/quicktime

This brief movie
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2007.03.02-Immigration, Achievement Gaps, and the Mis-Education of Utah Latina/os
Enrique Aleman discusses his views on immigration and notes the benefits a bilingual Hispanic population brings to Utah.
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17.315 Comparative Health Policy (MIT)
This course examines in comparative prospective the health care policy problems facing the United States including providing adequate access to medical services for all, the control of rising health care costs, and the assurance that the quality of health care services is high and improving. It explores the market and regulatory policy options being debated politically in the United States to solve these problems and compares possible foreign models for reform including those offered by the Cana
Author(s): Sapolsky, Harvey

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Content within individual OCW courses is (c) by the individual authors unless otherwise noted. MIT OpenCourseWare materials are licensed by the Massachusetts Institute of Technology under a Creative C

Supporters of traditional marriage rally in Washington
Thousands who support traditional marriage gathered in front of the U.S. Capitol to march to the Supreme Court ahead of this week's hearing on gay marriage. Rough Cut (no reporter narration). Subscribe: http://smarturl.it/reuterssubscribe More updates and breaking news: http://smarturl.it/BreakingNews Reuters tells the world's stories like no one else. As the largest international multimedia news provider, Reuters provides coverage around the globe and across topics including business, financi
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1.1 How has the human population grown?

For most of human history there have been relatively few people in the world. Figure 2 shows that only over the last 50 years have numbers really shot up, and that, at the turn of the century, the population reached over six billion.

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The Young People's Chorus of New York City
The Young People's Chorus was founded by conductor Francisco Nuñez to celebrate the diversity and musical richness of his hometown, New York City. In this performance video from From the Top at Carnegie Hall, listen to a performance of Panta Rhei (Greek for "all things are in flux") by another New Yorker, composer Jim Papoulis. Many of the musical elements—a driving rhythm, syncopation, atonality, and surprising percussion—contribute to the sense of change and movement. 
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3.3.2 Water pollution from coal mines

Most underground and some surface mines lie well below the water table. Both therefore have the potential to pollute any groundwater that flows through them. The root cause of the problem is the action of aerobic bacteria on pyrite (FeS2) within the coal sequence. This process releases metal and sulphate ions into solution, which in turn causes the acidity of the mine water to increase:

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3.6 Summary of Section 3

  1. The electronic configuration of an atom can be obtained by allocating its electrons to s, p, d and f sub-shells in the order given by Figure 21. This procedure generates a periodicity in electronic configuration which matches that of the Periodic Table.

  2. The typical elements have outer
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