Medical statistics
This free course is concerned with some of the statistical methods used in epidemiology and more widely in medical statistics. Section 1 introduces cohort studies in which individuals are classified according to their exposure and followed forward in time to evaluate disease outcomes. Section 2 looks at models for cohort studies. Section 3 introduces case-control studies in which individuals are selected according to their disease status and past exposures are then ascertained. Section 4 covers
Author(s): Creator not set

Division is probably the most awkward of the four arithmetic operations. Since you may have a calculator, you do not need to be able to carry out complicated divisions by hand, but you do need to carry out simple divisions in order to check your calculator calculations. Division is the reverse process of multiplication. The quantity 12 ÷ 3 tells us how many times 3 goes into 12. Since 4 × 3 = 12, 12 ÷ 3 = 4.

Author(s): The Open University

In order to compare quantities, it is best to express them in the same units.

## Example 10

Three children have just measured their own heights in metric units. Isaac says ‘My height is 1098’, Jasmine says ‘My height is 112’ and Kim says ‘Mine is 1.1’. What units were
Author(s): The Open University

Now that you’ve learned the principles of doing division on paper, you may want to practise your new skills. If so, go to the Dividing decimals page of the math.com website and follow the instructions. You will need a pen and paper to carry out each calculation. You can then enter your answer on the website to check if it is correct.

Author(s): The Open University

In Part C you have learnt that:

• accurate law reporting allows for legal principles to be collated, identified and accessed;

• there are many sources of law reports: Year Books (1275–1535), private reports (1535–1865), modern reports (1865 to present), the Law Reports, Weekly Law Reports, All England Law Reports, legal periodicals and newspapers, European Community Reports, DVD-ROMs and legal databases available via the internet.

Author(s): The Open University

The Sun emits electromagnetic radiation with a range of wavelengths, but its peak emission is in the visible band - the sunlight that allows us to see. The wavelength of radiation has important climatic implications, as we shall see shortly. For now, we are mainly interested in the overall rate at which energy in the form of solar radiation reaches the Earth.

Author(s): The Open University

Can renewable energy sources power the world?
We ask the question ‘Can renewable energy sources power the world?’ as a response to the growing awareness that increased use of renewable energy technologies is making a major contribution to global efforts to limit anthropogenic climate change. The course begins by examining the environmental concerns that have caused a rise in interest in renewable energy, introducing the main sources and technologies, and describing global efforts to increase the share of renewables. The course then look
Author(s): Creator not set

## SAQ 9

Look back at Figure 7. In this schematic representation, what is the fate of incoming solar radiation?

It is either reflected back to spa
Author(s): The Open University

Environmental responsibility – caring and generating accountability – requires interaction between human and non-human nature. For example, from a caring perspective what matters in climate change might constitute, say, the continued existence and protection of an arctic wilderness (Figure 3). But this necessarily involves a conn
Author(s): The Open University

The chart below shows a record of the global mean surface temperature of the Earth compiled for the past 140 years. Clearly there is an upward trend, but what does a chart like this really show?

Now we will explore multiple causes using an example familiar to us all – road accidents. The deaths of about 10 people each day on the UK's roads are less dramatic than, for example, the capsize of the Herald of Free Enterprise, but one feature that links them both is the element of risk associated with everything we do – and even with inaction.

We have just seen that many factors contribute to the risks which result from the inherent hazards associated with something we do.
Author(s): The Open University

Health and environment
To be able to understand the importance of the environment for our health, we need to know a little about the interdependence between environment and humankind. This free course, Health and environment, will look at interactions between plants, animals and the physical and chemical environment, as well as considering ways in which humans have altered, and are altering this environment. Author(s): Creator not set

The issue of climate change draws attention to the power of human activity to transform the planet in its entirety, and it is brought into sharp focus by the predicament of low-lying islands like Tuvalu. As we have seen in this course, the issue of rising sea level and other potential impacts of changing global climate also point to the transformations in the physical world that occur even without human influence. Oceanic islands provide a particularly cogent reminder that the living things w
Author(s): The Open University

Innovation Design: Sustainable Communities
Can you picture the future in a world without fossil fuels? Perhaps you think that living an "alternative" lifestyle has to mean painful and radical changes to the way you live now. This album looks at various small scale initiatives which show that living sustainably may not be as unpalatable as you might imagine. Bedzed, Findhorn, Hockerton, Samsoe Island; these are all decentralised communities at the forefront of a major social and technological experiment. In our world of finite resources a
Author(s): The OpenLearn team

• Largely because of expectations created in childhood (our 'inner child of the past'), we have many unconscious expectations of leaders, and may well harbour resentments, anxieties, suspicions, subservience, passive resistances and attitudes to leadership that have little relationship to current adult realities.

• The leader needs to be able to manage these feelings and his or her own responses to them.

• Leaders will tend to emerge
Author(s): The Open University

Trait theories are based on the assumption that the determining factor in an effective leader is a set of personal characteristics. It is also assumed that the way to discover these characteristics is to study successful leaders and determine which characteristics they have in common. However, despite innumerable studies, only about 5 per cent of the characteristics identified in successful leaders have been found to be widely shared. Of these, three stand out as significant:

Author(s): The Open University

Collins, S., Ghey, J. and Mills, G. (1989) The Professional Engineer in Society, London: Jessica Kingsley Publishers.
Foster, J., with Corby, L. (illustrator) (1996) How to Get Ideas, San Francisco: Berrett-Koehler Publishers, Inc.
Haaland, J., Wingert, J. and Olson, B. A. (1963) 'Force required to activate switches, maximum finger pushing force, and coefficient
Author(s): The Open University

The problem we will look at in this section concerns the analysis of the design of a component used in cars that are fitted with airbags. The airbag has to be inflated rapidly when an electronic circuit in the system decides that a serious collision is taking place. The crucial component in the electronics is the accelerometer, which therefore has to be extremely reliable. Motor manufacturers have turned to a technology called MEMS (micro-electromechanical systems) for these accelerometers, b
Author(s): The Open University

Course image: Shever in Flickr made available under Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Licence.

Grateful acknowledgement is made to the following sources for permission to reproduce material in this course:

Pages 36–37: Edwa
Author(s): The Open University

Nano is a prefix that means 10−9, i.e. very, very small. You may have come across nanotechnology. Nanofiltration is similar to reverse osmosis and employs membranes that are capable of physical sieving and diffusion-controlled transport. Nanofiltration systems operate at much lower pressures than reverse osmosis systems, but yield higher flow rates of permeate. The quality of the permeate is not as good as with reverse osmosis, with particles in the size range 0.0005–0.005 μm
Author(s): The Open University