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2.4 Sources of errors

The following is a list of common problems that can lead to medication errors. They fall into three broad categories according to where they occur in the sequence from a drug being prescribed to it being administered to a patient. As you can see, the same types of mistake can occur in each category. Those errors that involve maths are highlighted in italics:

Prescription errors

  • Wrong drug prescribed (contraindicated, or allergy, o
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2.1 Differences between accuracy and precision

Accuracy is a measure of how close a result is to the true value. Precision is a measure of how repeatable the result is. For instance, a group of three friends tried the shooting gallery at a fair and their targets are shown in Figure 6. The first person was an expert marksman, but they were using a rifle with sights that had not
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1.11 Addition and subtraction in practice – fluid balance

A common healthcare example that uses addition and subtraction involves calculating the fluid balance of a patient.

Fluid balance is a simple but very useful way to estimate whether a patient is either becoming dehydrated or overfilled with liquids. It is calculated, on a daily basis, by adding up the total volume of liquid that has gone into their body (drinks, oral liquid medicines, intravenous drips, transfusions), then adding up the total volume of liquid that has come out of their
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1.9 Addition of decimal numbers

If we add 109.8 ml of one liquid to 6.5 ml of another liquid, what would be the total volume of liquid in ml?

To compare 109.8 with 6.5, you need to remember that

Place the two numbers in a grid on top of each other and make sure that columns representing the same magnitude line up wit
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4.3.2 Stage 2: Embryonic ocean basin formation (southern Red Sea stage)

If extension and rifting progresses sufficiently, this will lead to the development of an embryonic ocean along the site of the earlier rift zone (see Figure 6b). Prior to true oceanic lithosphere being produced, basaltic magma will be repeatedly intruded into the continental lithosphere along fractures and shear
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3.10 Moon42: Apollo 15 station 10

James B. Irwin took this pan moments after he and Dave Scott arrived at Station 10. (QuickTime, 500KB, note: this may take some time to download depending on your connection speed)

6.2 Chemical symbols

So far, atoms have been represented as labelled spheres or circles and the bonds that link atoms in molecules have been represented as lines. This is a rather cumbersome method of writing down molecules. Chemists have developed their own shorthand language for the names of the elements. It involves giving each element a symbol consisting of one or two letters. You can guess some of them, because they start with the first letter of the element's name. Thus oxygen is designated by
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3.5 Electrophysiological studies of language processing

Brain imaging and aphasic studies helped us localise the subparts of language processing within the brain. However, they have shed little light on how processing unfolds in real time. This is because contemporary brain imaging is quite poor at showing changes in activity through time in fine detail, so it is hard to pick up something that may be happening slightly before something else.

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2.5 From phoneme to sentence structure: the syntactic problem

In the vervet monkey system, calls stand by themselves. Thus there is no syntax. Syntax can be thought of as working like road traffic rules do. It doesn't much matter which side of the road you drive on, as long as there is some clear convention. Similarly in (13), it is necessary to understand the difference between (13a) and (13b) without ambiguity, by having some rule or other about which noun phrase comes first. England may differ from most of the rest of the world in terms of the side o
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11.3 Frequency selectivity

In preceding sections we examined two ways in which the auditory system may code frequency information: the place theory and phase locking. In this section we will look at the psychophysical evidence for place coding on the basilar membrane by examining the ability of the auditory system to resolve the components of sinusoidal waves in a complex sound – a phenomenon known as frequency selectivity.

The perception of a sound depends not only on its own frequency and intensity but also o
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9.3.1 Weber's Law

Pioneering work on the relationship between ΔI and S was done by the German physiologist, Ernst Weber in the 1830s. Weber found that the increment in stimulation required for a JND was proportional to the size of the stimulus. Weber had subjects lift a small ‘standard’ weight (S) and then lift a slightly heavier ‘comparison’ (T) weight and judge which was heavier. He found that when the difference between the standard and comparison weights was small, the subjects found
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3.5.2 Mechanical force directly opens and closes transduction channels

It is believed that tip links aid in causing ‘channels’ to open and close near the top of the hair cell (Figure 16). Tip links are filamentous connections between two stereocilia. Each tip link is a fine fibre obliquely joining the distal end of one stereocilium to the side of the longest adjacent process. It is thought that each l
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2.1.2 Mathematics and quantification

Roger Bacon once said ‘Mathematics is the door and the key to the sciences’. This statement aptly summarises the role of mathematics in science, particularly in physics, and it is not hard to see why.

Much of physics is concerned with things that can be measured and quantified, that is, expressed as numbers, multiplied by an appropriate unit of measurement such as a metre or a second. It is natural to turn to mathematics to try to reveal patterns underlying such measured data. This
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3.3 Integration of anatomical features and biochemical and physiological strategies in evaporators

Birds and larger desert mammals that use evaporative cooling risk dehydration because of the difficulty of finding sufficient drinking water. For mammals, evaporative heat loss includes panting and sweating.

In small mammals and birds the temperature of exhaled air is often lower than T b, resulting in condensation of water on the nasal mucosa. Small desert mammals rely on this mechanism for water conservation, while resting in their cool burrows during the heat of the
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3.2 Integration of anatomy and behaviour with biochemical and physiological strategies in evaders

We know from Section 2.3 that small desert rodents remain cool by staying in their burrows for all or part of the day. Kangaroo rats (Dipodomys spp.; see Figure 20 in Section 2.3) depend on metabolic water as there is little or no water available in their diet of seeds. Kangaroo rats appear to be ill-adapted for
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3.5.1 Final arousal

Emergence can be viewed as the final step in the series of periodic arousals. Instead of re-entering hibernation, the animal maintains the euthermic condition. The cue for maintaining this final arousal is probably not temperature, as some species emerge when T a is well below zero. It is also difficult to see how arousal could be affected by daylength, since the hibernating animal is usually underground in a cavity or a burrow. Perhaps fat or food stores reach a minimum lev
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4.5.4 Phosphorus

Phosphorus is recognised as a potential poison for automotive catalysts. The phosphorus level in fuel is generally very low (2×10−5 g l−1), but it is present in higher concentrations in engine oils (1.2 g l−1). Phosphorus derived from the engine oil is believed to react with the alumina support, and also to reduce the activity of the noble metal component. This deactivation is particularly important for Pd, with which phosphorus may form an all
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Learning outcomes

Having read this unit you should be able to:

  • discuss how the gas mixture expelled from the engine, and the conversion performance of the three-way catalytic converter, depend on the air/fuel (A/F) ratio;

  • list the chemical reactions whereby the three-way catalyst removes carbon monoxide (CO), hydrocarbons and oxides of nitrogen (NOx) from petrol vehicle exhausts;

  • interpret the results of experimental studies (involving activity test
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Acknowledgements

Except for third party materials and otherwise stated (see terms and conditions), this content is made available under a Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Licence

All materials included in this unit are derived from content originated at the Open University.


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3.7 Vitamin C (ascorbic acid)

Activity 14

What is the condition that results from vitamin C deficiency and what are its symptoms?

Answer

You will probably remember from the start of this
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