Pages 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 10418 result(s) returned

3.4.1 Plant nutrients

Plant nutrients are necessary in varying amounts for the growth, reproduction and well-being of growing plants.

Of the major nutrients of plants, nitrogen and phosphorus are important growth-limiting factors in primary production (i.e. they are likely to run out before any other element needed by the plants). Both nitrogen and phosphorus enter watercourses from natural leaching by water of the soluble nitrates and phosphates found in soils and rocks, as well as from sewage effluent and
Author(s): The Open University

License information
Related content

Copyright © 2016 The Open University

3.3.3 Temperature

All aquatic organisms have a fairly well-defined temperature tolerance range and this determines their distribution. Temperature affects the saturation concentration of dissolved oxygen (as seen in Table 2). An increase in water temperature will reduce the oxygen solubility as well as increase the metabolic activity of aquatic organisms. The combination of these two effects means that oxygen demand by organisms increases just when oxygen supply is being reduced.

Coarse fish such as perc
Author(s): The Open University

License information
Related content

Copyright © 2016 The Open University

3.2 Dissolved oxygen

Organic and inorganic nutrients are the basic food supply essential for maintaining the plants and animals in natural watercourses. Equally essential to aquatic life is a supply of oxygen, needed for respiration. Oxygen dissolved in the water is also needed in the biodegradation of organic matter by aerobic (oxygen-consuming) bacteria. A measure of this oxygen demand can be obtained experimentally and is defined as the biochemical oxygen demand (BOD). The BOD i
Author(s): The Open University

License information
Related content

Copyright © 2016 The Open University

2.11 Storage

In a given fixed space at any phase of the hydrological cycle, there is an inflow and an outflow of water, the rates of which vary with time. The total cumulative difference between inflow and outflow is the storage. So within that space there is a body of water whose mass is not directly controlled by instantaneous values of inflow and outflow. For example, in river flow the movement of the whole body of water in the channel is generally downstream, yet a given reach contains a volume whose
Author(s): The Open University

License information
Related content

Copyright © 2016 The Open University

4 Introduction to systems practice

This course teaches some aspects of systems thinking and practice. But what does it mean to be a systems practitioner, and is it different to being a manager? This section attempts to answer those questions.

First, I believe a good systems practitioner will be more competent at handling complex situations, more capable of managing their working and domestic lives, and more able to learn not only how to learn but also how to act more effectively by using systemic concepts and techniques.
Author(s): The Open University

License information
Related content

Copyright © 2016 The Open University

1.7 Conclusions

Could both of these students have got more from their involvement with the course if they had taken time to reflect on their goals and their strengths and weaknesses, especially at the beginning of study? Alan, whose reaction to the course was positive, for example, could have learned more about how the course succeeded if he had reflected rather more in the beginning about his initial scepticism and his preference for communicating verbally rather than in writing. What was the reason for his
Author(s): The Open University

License information
Related content

Copyright © 2016 The Open University

Acknowledgements

The content acknowledged below is Proprietary (see terms and conditions) and is used under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence.

Course image: drpavloff in Flickr ma
Author(s): The Open University

License information
Related content

Copyright © 2016 The Open University

3.4.6 Residual stress

One factor that can cause serious problems in any material is the presence of residual tensile stress. The problem often arises as a direct result of manufacturing, when hot material is shaped and then allowed to cool to ambient temperatures. For large castings like those needed to make the eye bars, such residual stress would be modified by the subsequent heat treatment to strengthen the steel, but had to be studied as part of the research effort into the catastrophic failure of the bridge.<
Author(s): The Open University

License information
Related content

Copyright © 2016 The Open University

3.2 The disaster

The 39-year-old Silver Bridge collapsed suddenly at about 5 p.m. on 15 December 1967 when the roadway was filled with rush-hour traffic – 37 vehicles were trapped on the roadway.

The first signs of collapse were later recounted by the survivors. Many occupants of the cars on the bridge had felt it ‘quivering’ before it fell. Most witnesses had then heard ‘cracking’ or ‘popping’ noises, some saying that it sounded like a ‘shotgun blast’. After this, the bridge started d
Author(s): The Open University

License information
Related content

Copyright © 2016 The Open University

2.6.1 Stress corrosion cracking in stainless-steel structures

On 9 May 1985 the roof of a swimming pool at Uster near Zurich collapsed, killing 12 and injuring several others.

The concrete roof had been held up by a set of stainless-steel tie bars, which were found after the accident to have cracked transversely (Figure 21). Chlorine is added at qu
Author(s): The Open University

License information
Related content

Copyright © 2016 The Open University

The Arts Past and Present: Mosaics
How can we read an image to tell us more about its ancient maker? In this album a mosaic artist, Catherine Parkinson, visits the splendidly-preserved ancient Roman mosaics at Brading Villa on the Isle of Wight. With the help of two archaeologists she discovers that the iconography reveals important clues about the villa inhabitants' world view, taste, and aspirations. Their leisure pursuits, the value placed on learning, and their views on men and women are just some of the themes revealed in
Author(s): The OpenLearn team

License information
Related content

Except for third party materials and otherwise stated (see http://www.open.ac.uk/conditions terms and conditions), this content is made available under a http://creativecommons.org/licenses/by-nc-sa/2

Thought and Experience
This album contains fascinating and engrossing interviews with several leading philosophers concerning, primarily, the exploration of four topics: emotion; thought and language; imagination and creativity; consciousness. The interviews contain lively debates from differing philosophical viewpoints, discussions about theoretical thought experiments and the examination of theories developed by philosophers such as Aristotle, Decartes, Galileo, and Hume as well as predictions regarding the future
Author(s): The OpenLearn team

License information
Related content

Except for third party materials and otherwise stated (see http://www.open.ac.uk/conditions terms and conditions), this content is made available under a http://creativecommons.org/licenses/by-nc-sa/2

The Arts Past and Present: Diva
How do you get to be one of the great operatic divas? Catherine Rogers might just have what it takes to be a famous opera singer, but she still has lots of work to do. This album gives us an insight into the immense effort it requires to become a musical performer. As well as singing, acting, language, and stage skills all need to be honed. Catherine tackles the tragic aria of the Countess in Mozart's Marriage of Figaro and is praised by her tutors. In the audio track Elaine Moohan from the Musi
Author(s): The OpenLearn team

License information
Related content

Except for third party materials and otherwise stated (see http://www.open.ac.uk/conditions terms and conditions), this content is made available under a http://creativecommons.org/licenses/by-nc-sa/2

Exploring Greek vases
What can you learn about an archaic community from the art they created? Can the way in which their artefacts are displayed enhance the experience of viewing it? Very few remains still exist from Ancient Greek culture on the whole. However because of the durability of the material, pottery is a large part of the archaeological record from this period in Greece’s history, and as a result these vases have exerted a disproportionately large influence on our understanding of Greek society. These f
Author(s): The OpenLearn team

License information
Related content

Except for third party materials and otherwise stated (see http://www.open.ac.uk/conditions terms and conditions), this content is made available under a http://creativecommons.org/licenses/by-nc-sa/2

Introduction

This course investigates certain philosophical issues concerning imagination, creativity and the relationships between them, and considers the conceptions and varieties of imaginative experience.

This OpenLearn course provides a sample of Level 3 study in Arts and Humanities.


Author(s): The Open University

License information
Related content

Copyright © 2016 The Open University

An introduction to music research
In this free course, An introduction to music research, we have gathered together materials to allow you to explore the ways in which music may be researched. After thinking about different kinds of musical knowledge and their relationship with various musical practices (including performance, composition, and listening), you'll be introduced to some of the digital resources and methodologies that inform music research. The next section, which constitutes the main part of the course, explores a
Author(s): Creator not set

License information
Related content

Except for third party materials and otherwise stated (see http://www.open.ac.uk/conditions terms and conditions), this content is made available under a http://creativecommons.org/licenses/by-nc-sa/2

Artists and authorship: the case of Raphael
Individual artists have been the traditional focus of art history, but how do we evaluate the figure of the artist? This free course, Artists and authorship: the case of Raphael, takes the life of Raphael as a case study. You will examine sixteenth-century sources to explore the creation of artistic authorship in the early modern era. The course explores past and current approaches to the artist in terms of authorship, identity and subjectivity. You will consider issues such as the relationship
Author(s): Creator not set

License information
Related content

Except for third party materials and otherwise stated (see http://www.open.ac.uk/conditions terms and conditions), this content is made available under a http://creativecommons.org/licenses/by-nc-sa/2

Religious diversity: rethinking religion
Religion is not necessarily what you think it is! This free course, Religious diversity: rethinking religion, introduces you to a selection of the vast variety of religious beliefs and practices in Britain today. Having some familiarity with religion and belief is increasingly required to make sense of issues of local, national and international importance. The course will introduce you to issues and skills necessary for better understanding and interacting with religiously-motivated people in t
Author(s): Creator not set

License information
Related content

Except for third party materials and otherwise stated (see http://www.open.ac.uk/conditions terms and conditions), this content is made available under a http://creativecommons.org/licenses/by-nc-sa/2

Introduction to law in Wales
This free course, Introduction to law in Wales, gives a brief overview of the legal history in Wales from the 12th century, followed by an overview of devolution and referendums, the law making powers of the Welsh Assembly and the possible future for legal Wales. First published on Mon, 21 Mar 2016 as Author(s): Creator not set

Methodism in Wales, 1730–1850
In this free course, Methodism in Wales, 1730–1850, you will learn about a neglected strand of Welsh history and identity. By the mid-nineteenth century, Calvinistic Methodism had become the most popular religious denomination in Wales and a mainstay of Welsh national identity. Where did this new form of religion come from? Why did it become so popular? And how did it become so intertwined with ideas about Welshness? These are the questions this course will consider, and at the same time it wi
Author(s): Creator not set

License information
Related content

Except for third party materials and otherwise stated (see http://www.open.ac.uk/conditions terms and conditions), this content is made available under a http://creativecommons.org/licenses/by-nc-sa/2

Pages 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521