4.7 Jets

You have seen that two kinds of active galaxies - quasars and radio galaxies - are often seen to possess narrow features called jets projecting up to several hundred kiloparsecs from their nuclei. If these are indeed streams of energetic particles flowing from the central engine, how do they fit with the accretion disc model? How could the jets be produced?

The answers to these questions are not fully resolved, but there are some aspects of the model of the central engine which probably
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2.2.2 Energy and conservation

Newtonian mechanics is concerned with explaining motion, yet it contains within it the much simpler idea that some things never change. Take the concept of mass, for example, which appears throughout Newtonian mechanics, including the law of gravitation. In Newtonian mechanics, mass is conserved. This means that the mass of the Universe is constant and the mass of any specified collection of particles is constant, no matter how much rearrangement occurs within the system. A chemist might take
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The Organ of Corti
Situated in the spiral-shaped cochlea of the inner ear is the organ of Corti. Only one inch long if uncoiled, it bears about twenty-five thousand sound receptor cells with hairlike projections arranged in rows on the basilar membrane. Diagrams show detailed structure of the organ of Corti. Grades 5-12. 1 min.
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Free Hugs Campaign
Free hugs campaign. Good for service-learning classes. (03:40)
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9.2 Antisocial behaviour disease

The psychological arena is hugely complex because there are additional issues of responsibility and treatment. Briefly, society takes a more lenient attitude towards the behaviour of someone who is ill (diseased) compared to someone who is well. The diseased person is not fully responsible for their actions (‘They can't help it’). Therefore any individual with antisocial (aggressive) behaviour who is diagnosed as having a disease is largely absolved of blame. Having a disease, means, at l
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5 Biomass conversion of solar energy

Photosynthesis in the geological past was responsible for all fossil fuel reserves, but its products are buried about 2000 times more slowly than we use them at present. The total carbon content of all biomass growing on land is estimated to be 5.6 × 1014 kg and, as Figure 10 shows, about one-fifth of this mass is renewed each year. Figure 6 shows how modern plant biomass is distributed across the continents. Clearly, biological conversion of solar energy to a chemical form in com
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References

Huse, M. and Kuriyan, J. (2002) The conformational plasticity of protein kinases, Cell, 109, pp. 275–282.
Lipscomb, W. N., Reeke, G. N. Jr, Hartsuck, J. A., Quiocho, F. A. and Bethge, P. H. (1970) The structure of carboxypeptidase A. 8. Atomic interpretation at 0.2 nm resolution, a new study of the complex of glycyl-L-tyrosine with CPA, and mechanistic deduction
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An introduction to software development
Software development is the practice of organising the design and construction of software, the beating heart of much technology fundamental to our personal and professional life. This free introductory course, An introduction to software development, discusses the engineering nature of software development, its challenges and some fundamental practices which have developed to meet them. Software development is a fast-moving discipline and as a software development professional you must be
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1.3 Coal-forming environments today

Coal formation begins with preservation of waterlogged plant remains to produce peat and then slow compression as the peat is buried. About 10 m of peat will compress down to form about 1 m of coal; clearly large amounts of plant debris must be available for preservation. Even so, for a significant thickness of peat to accumulate there must be a balance between the growth of plants and the decay of underlying dead material to form peat (a process known as humification).

Su
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Stem Cell Therapies are no More Drugs Than Soufflés are Fast Food
Stemcell discoveries make great news stories, but their actual translation into routine clinical practice is still a major hurdle. Is it reasonable to expect the big pharmaceutical companies to manufacture these living therapies or is the paradigm shift from today’s drugs to ‘living cells as therapies’ overwhelming? Would McDonald’s ever put delicate soufflés on their fast-food menus? This lecture will use examples from current cell and tissue-engineered clinical therapies to illustrate
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3.3 Business operations: a transformation process

The view that operations is the set of processes responsible for producing the organisation's intended outputs from an appropriate range of resource inputs can be represented very simply, as in Figure 2.

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7.2 The professional engineer

It has been suggested that there are four main criteria that identify a profession:

Custody of a clearly definable and valuable body of knowledge and understanding associated with a long period of training.

A strong unitary organization which ensures that the profession generally speaks with 'one voice'.

Clearly defined and rigorous entry standards, backed up by a requirement to register with the profession
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7.1 The engineer and society

Section 2 outlined some of the needs for engineering. Society relies on engineers to create solutions to the problems involved in meeting those needs.

This is a good time to pause and point out that inevitably, in return for all this fun and power, engineers have a responsibility to society. The people who employ our services, directly or indirectly, have to have an assurance that we are working within certain social, safety and ethical boundaries. Particularly given the increasing tren
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5.8.2 Removal of trace organic compounds

After conventional treatment, water may still contain trace concentrations of synthetic organic compounds, which, if left in the water, can lead to taste and odour problems. The problem is most likely to arise where the raw water source has been badly polluted. The problem can be solved by including the process of granular activated carbon adsorption after the filtration process. Activated carbon is carbon which has been activated by heating in the absence of oxygen. This resu
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5.8.1 Nitrate removal

Nitrate in water has become a significant problem and the EU Directive sets a maximum admissible concentration of 50 g m−3 measured as NO3. This is equivalent to 11.3 g m−3 as N. High nitrate levels can cause cyanosis or methaemoglobinaemia in babies. Legislation allows the designation of nitrate-vulnerable zones and these help to prevent nitrate levels in natural waters increasing in affected areas.

Ion exchange is used in some
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Developing career resilience
This free course, Developing career resilience, will help you to understand the factors that influence career resilience and offer examples and tactics for you to develop your own resilience further. First published on Thu, 09 Aug 2018 as Developing career re
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Introduction

Relational database systems underpin the majority of the managed data storage in computer systems. This course presents an overview of the development life cycle for a database system and highlights how the database development differs from traditional software development.

This OpenLearn course provides a sample of Level 3 study in Author(s): The Open University

Systems thinking and practice
What is systems thinking and practice? The essence of systems thinking and practice is in 'seeing' the world in a particular way, because how you 'see' things affects the way you approach situations or undertake specific tasks. This free course will help you to learn about the problems of defining a system and meet some of the key concepts used in systems theory: boundary, environment, positive and negative feedback, etc. Author(s): Creator not set

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The internet of everything (IoE) is the networked connection of people, process, data and things. As more people, data and things come online, we develop processes to harness the vast amounts of information being generated by all these connected people and things. The goal of this free course is to introduce you to fundamental concepts and technologies that enable the IoE and the internet of things. Author(s): Creator not set

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Discovering Wales and Welsh: first steps
This free course, Discovering Wales and Welsh, introduces you to who the Welsh people are via a brief look at history and two significant figures, Owain Glyndŵr and Llywelyn the Last. You will also learn the basics of Welsh pronunciation and how to greet people in Welsh. First published on Mon, 07 Mar 2016 as Author(s): Creator not set