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| == '''[[Food reward]]''' ==
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| Food intake involves both 'homeostatic feeding' (energy demands) and ‘non-homeostatic feeding’; the latter is associated with '''food reward''', which involves both 'liking’ (pleasure/palatability) and ‘wanting’ (incentive motivation) according to the ''salience theory''. Experiments in mice suggest that ‘liking’ involves the release of mu-[[opioid peptide]]s in brain, while ‘wanting’ involves the neurotransmitter [[dopamine]] <ref>Berridge KC (2007) The debate over dopamine’s role in reward: the case for incentive salience. ''Psychopharmacology'' 191:391–431</ref>.
| | ==Footnotes== |
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| ==='''Motivated behaviour and food as a reinforcer'''=== | |
| The brain’s reward systems react to stimuli such as sight, smell and taste, and other cues that predict food. However, hunger cannot result in unconditioned goal-directed behaviour; <ref>Changizi MA ''et al.'' (2002) Evidence that appetitive responses for dehydration and food-deprivation are learned ''Physiol Behav'' 75:295–304</ref> chance encounters with palatable foods are required before goal-directed behaviour can occur, which link the internal needs with the salience of environmental stimuli <ref>Wise RA (2006) Role of brain dopamine in food reward and reinforcement ''Phil Trans R Soc Lond B Biol Sci'' 361:1149–58</ref>For exa mple, an infant recognises and learns to seek out sweet tastes, but the desire for any particular food is controlled by the interaction of peptide levels (related to hunger) with neural circuits in the brain which store the animal’s past experience of that particular food. <ref>Steiner JE ''et al.''(2001) Comparative expression of hedonic impact: affective reactions to taste by human infants and other primates ''Neurosci Biobehav Rev'' 25:53–74</ref> Subsequently, the infant will taste both food and non-food objects indiscriminately until it has received reinforcing feedback from enough stimuli. A monkey’s appetite for yellow bananas requires that the monkey learns to relate the sight of the yellow skin of a banana with the sweet taste of the banana, plus the consequences of eating it. Preference for a particular food results only when the post-ingestional consequences of that food ’reinforce’ the tendency to eat that food. For these reasons, food is considered to be a strong reinforcer. When the response of a behaviour stimulated by a reinforcer increases the frequency of that behaviour; that is ''positive reinforcement'' or ''reward learning'', and the positive events are called ''rewards'' <ref>Epstein LH ''et al.''(2007) Food reinforcement and eating: a multilevel analysis ''Psychol Bull'' 133:884–906</ref>. The reinforcing efficacy of food reward is the ability of the reward to maintain rather than to establish behaviour; consequently the stimulus learning contributes to the response learning.
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Latest revision as of 10:19, 11 September 2020
After decades of failure to slow the rising global consumption of coal, oil and gas,[1] many countries have proceeded as of 2024 to reconsider nuclear power in order to lower the demand for fossil fuels.[2] Wind and solar power alone, without large-scale storage for these intermittent sources, are unlikely to meet the world's needs for reliable energy.[3][4][5] See Figures 1 and 2 on the magnitude of the world energy challenge.
Nuclear power plants that use nuclear reactors to create electricity could provide the abundant, zero-carbon, dispatchable[6] energy needed for a low-carbon future, but not by simply building more of what we already have. New innovative designs for nuclear reactors are needed to avoid the problems of the past.
(CC) Image: Geoff Russell Fig.1 Electricity consumption may soon double, mostly from coal-fired power plants in the developing world.
[7] Issues Confronting the Nuclear Industry
New reactor designers have sought to address issues that have prevented the acceptance of nuclear power, including safety, waste management, weapons proliferation, and cost. This article will summarize the questions that have been raised and the criteria that have been established for evaluating these designs. Answers to these questions will be provided by the designers of these reactors in the articles on their designs. Further debate will be provided in the Discussion and the Debate Guide pages of those articles.
- ↑ Global Energy Growth by Our World In Data
- ↑ Public figures who have reconsidered their stance on nuclear power are listed on the External Links tab of this article.
- ↑ Pumped storage is currently the most economical way to store electricity, but it requires a large reservoir on a nearby hill or in an abandoned mine. Li-ion battery systems at $500 per KWh are not practical for utility-scale storage. See Energy Storage for a summary of other alternatives.
- ↑ Utilities that include wind and solar power in their grid must have non-intermittent generating capacity (typically fossil fuels) to handle maximum demand for several days. They can save on fuel, but the cost of the plant is the same with or without intermittent sources.
- ↑ Mark Jacobson believes that long-distance transmission lines can provide an alternative to costly storage. See the bibliography for more on this proposal and the critique by Christopher Clack.
- ↑ "Load following" is the term used by utilities, and is important when there is a lot of wind and solar on the grid. Some reactors are not able to do this.
- ↑ Fig.1.3 in Devanney "Why Nuclear Power has been a Flop"
