bluuebunny/crossref_metadata_2025 huggingface dataset:
Why isn’t everyone a vampire?
Authors: Rowson Martin
Published: November 2023

Readers of a perverse turn of mind will have wondered at the epidemiology of vampirism as it is described in Stoker’s Dracula, and as it is displayed in the numerous film adaptations. The crucially puzzling passage is found in one of Van Helsing’s incidental lectures to his friends the Harkers and Lucy Westenra’s fiancé, Arthur. They are steeling themselves for the stake-through-the-heart operation which will ‘save’ (by truly ‘killing’) Lucy –– Dracula’s first English victim, as we understand (what, one wonders, happened to the crew of the Demeter, the vessel which brought the count to England?). To uninformed observers, Lucy has been dead and buried a week. But she has risen from her grave to suck the blood of children playing at dusk (it is late September, the days are short) on Hampstead Heath. Her little victims know her as the ‘Bloofer Lady’. Van Helsing knows her as one of the grisly army of the Un-Dead.
Egypt And The Holy Land
Authors: Robinson Jane
Published: November 2023

Too suggestive? Too confounding? But Egypt was the very place our doughty friend Impulsia Gushington chose as most likely to edify and entertain the noble heart of a tourist. Ida Pfeiffer, the first woman to make a successful career of travelling, found it both stimulating and enjoyable. Amelia Edwards's classic A Thousand Miles Up the Nile proclaimed it a surprisingly accessible treasure-ground of ancient civilization's richest pickings, there not just for the finding (simply kick the sand away a little) but for the taking home and showing off to one's friends too.
Risk and risk factors
Authors: Ebrahim Shah
Published: November 2023

In common with most chronic diseases, strokes do not have single causes, but seem to be multifactorial in their causation. However, even in infectious diseases that have a single cause, such as mycobacterium tuberculosis, the risk of being infected, and then of developing tuberculosis, is dependent on a chain of causal factors, some very closely related to the pathogenetic process (e.g. inhaling bacilli from a close relative), whereas others are much further back in the causal chain (e.g. poor childhood nutrition). Epidemiologists are frequently concerned with discovering characteristics of people and populations that increase or decrease their chances (or risk) of suffering diseases. The mechanisms by which disease occurs in those at increased risk is often suggested by epidemiological enquiry, but working out the final pathological pathways is a goal for laboratory scientists.
Recurrent stroke
Authors: Ebrahim Shah
Published: November 2023

‘Will it happen again, Doctor?’ The stroke patient is asking one of the most difficult questions to answer clearly and is expecting a straight yes or no. The clinician may toss a mental coin, and say ‘no’, realizing that this answer will be wrong some of the time but right most of the time. The response may be justified by the paternalistic notion that the patient really does not need negative ideas to ponder during the difficult period of recovery. An alternative is to give a probability of a further stroke. Depending on the optimism of the doctor this may be stated as a percentage chance of having a stroke or a much bigger chance of not having a stroke. The figure usually quoted is around IO per cent per year (Allen 1984a; Wade et al. 1985b).
Effects of stroke
Authors: Ebrahim Shah
Published: November 2023

Many of the effects of stroke are not obvious for weeks or months, and by this time the patient is often back at home if admission was sought during the acute phase. Follow-up by rehabilitation teams, hospital, and family doctors after a stroke is patchy, and certainly not related to need—if impairments and disability are accepted as indicators of need (Ebrahim et al. 1987b), so it is likely that many complications may go undetected. Avoidable complications of stroke have been reviewed (Mulley 1982), and for painful hemi plegic shoulders, spasticity, contractures, constipation, falls, and fractures there is nothing new to add. In the areas of depressed mood, cognition, dysphasia, urinary incontinence, dysphagia, deep vein thrombosis and pulmonary embolism, quality of life, and support for carers, more recent studies are available. The extent of these specific complications, their importance and management will be considered next.
Pregnancy and mental health
Authors: Brockington Ian
Published: November 2023

As with many psychological explorations, the early work was done by psycho analysts, e.g. Fries and Lewi114.who explored the feelings of three normal mothers in depth. Hall and Mohr pioneered a more systematic approach, interviewing 66 pregnant women in Chicago; this revealed ‘a host of mental-hygiene problems and situations inimical to the prospects of successful child-rearing’. Later, Loesch and Greenberg interviewed, on an average of five occasions, 53 pregnant women, including 31 unmarried mothers.
Drugs prescribed and abused
Authors: Brockington Ian
Published: November 2023

Whenever drugs are prescribed to a pregnant or lactating woman, the fetus is put at risk in a number of possible ways:

Mutagenicity. Some drugs cause mutations, affecting the ovum or spermatozoum before fertilization. Their frequency is thought to be related to the number of chromo somal gaps, chromosomal breaks or haploid cells. Lysergic acid may have this effect.
Introduction
Authors: Quick Clive R , Majeed Ali , Rooney Paul
Published: November 2023

Surgeons aspire to practise their craft in line with the principles of the Hippocratic oath. This oath originated from the Greek school of medicine around 500 BC. The essence of these principles is as follows: Doctors must be instructed and registered to protect the public from amateurs and charlatans. Medicine is for the benefit of patients and doctors must avoid doing anything known to cause harm. Euthanasia and abortion are prohibited.
Management of acute pain
Authors: Doyle Patrick , Munglani R
Published: November 2023

Pain is a subjective experience that can only be experienced directly by the sufferer. Nerve activation by noxious stimuli results in pain pathway activity that forms the central core of the perceived pain. However, emotional and behavioural dimensions to pain, for example suffering and anxiety, may also be experienced. This illustrates the complex nature of pain; the effective treatment of pain may require all these various levels to be addressed.
Critical care of the surgical patient
Authors: Pappachan V J , Jonas M M , Oduro A , Smith H S
Published: November 2023

The availability of adequately equipped and staffed recovery units and the lowering of the threshold for the admission of these patients to ITU are important advances in the management of postoperative surgical patients which have contributed towards improved quality of patient care. The perioperative mortality rate for elective surgery as a whole is between 0.5 and 1.9 per cent. However, this increases substantially when factors such as urgent and emergency operations, heart failure, chronic lung disease, and age over 75 years are involved. The most common complications contra to this increased morbidity and mortality are those of the circulatory and respiratory systems.
Soft-tissue surgery and wound management
Authors: Cross K Simon , Earley Michael J , Mccue Jane , Quick Clive R
Published: November 2023

Surgery of the superficial tissues requires care and attention to ensure that a good functional and cosmetic outcome is achieved. Skin operations are often regarded as ‘minor’ and are often per formed by general practitioners or assigned to the most junior member of the hospital surgical team. However, disasters can occur if assessment is not carried out adequately and an appropriate level of surgical expertise employed. The principles of asepsis/antisepsis pioneered by Semmelweis (1847) and Lister (1867) must also be observed. The underlying principles have changed little during the twentieth century, but the practice has evolved markedly, with new methods of sterilization, disposable items, and single-use packs improving the chances of maintaining sterility.
Elective upper gastrointestinal surgery
Authors: Botha Abrie , Hughes Frances , Thomas Dion Morton ,Paul
Published: November 2023

For a general surgeon, the foregut includes the embryological foregut and midgut, and the associated solid organs. This chapter deals sequentially with the common, and some not so common, disorders of the oesophagus, stomach, duodenum, liver, biliary tree, pancreas, and spleen.
Colorectal surgery
Authors: Saunders Mike , Abercrombie John , Everett Paul Thomas with W G , McGregor John
Published: November 2023

The surgical principles employed in most colorectal procedures have been steadily evolving over the past 120 years. Standard methods for resection of all parts of the colon have now been formalized and technical advances have been made with stapling devices which sometimes obviate the need for a permanent stoma in patients with low rectal carcinoma. The ability to anastomose bowel low in the pelvis at the level of the anorectal ring is the key advance, which allows low anterior resections and ideal pouch procedures to be undertaken. However, it is still necessary to pay close attention to the details of patient prepara tion if morbidity and mortality are to be kept at a minimum.
Venous and lymphatic disorders
Authors: Sarin S
Published: November 2023

Ulcerating wounds of the lower limbs must have been treated by innumerable men of medicine in the past, but the association between ulcers and varicose veins is attributed to Hippocrates of Cos (460-377 BC), who was also the first to recommend incision of the varies and compression, to squeeze out the ‘humours’. The rise of the Roman Empire saw Aulus Cornelius Celsus (AD 30) deal with the treatment of ulcers by bandaging with linen, and Galen (AD 130-200) is said to have popularized avulsion techniques of varicose veins. However, Galen’s erroneous views of anatomy and physiology, based on comparative anatomical dissections (he had little access to human post mortem specimens) and the dogmatic views of the Church, marked an enduring stagnation in the development of surgery in Europe throughout the Middle Ages.
Psychiatry and Psychopathology
Authors: Cutting J
Published: November 2023

There have been documented instances of madness for as long as there have been records of human activity. During Roman times, some consensus was reached as to how it should be classified, and this classification persisted largely unchanged until the beginning of the nineteenth century. The extent of the agreement is illustrated in Table 2.1, where the opinions of three of the most eminent Roman physicians and those of four subsequent writers on the topic are shown. There was one type associated with febrile illness-variously called phrenitis, frenisie, or delirium. There was dementia, also variously named. Then there was melancholia, So far, there was considerable agreement. But madness not accounted for by the above categories was the subject of much dispute. (What are now regarded as neurological, developmental, and neurotic conditions were placed in the same category as madness,)
Self
Authors: Cutting J
Published: November 2023

The self, as a unique unity of inward qualities, is a modern concept dating back no earlier than the beginning of the nineteenth century. In the words of Foucault (1966): ‘Man was constituted at the beginning of the nineteenth century’. The origins of the concept are well traced up to this period by van Peursen (1966), Wilkes (1988), and Taylor (1989).
Language
Authors: Cutting J
Published: November 2023

The study of language for itself is largely a development of the late nineteenth and twentieth centuries. Saussure (1857-1913) is regarded as the seminal figure who founded linguistics, with his posthumous Cours de linguistique generale published in 1916. Therefore views on the nature of language can be conveniently considered under three headings: pre-Saussurian, Saussurian, and post-Saussurian.
What is medical audit?
Authors: Lawrence Martin
Published: November 2023

Audit is such an unsatisfactory term that it is hard to understand how it ever became adopted by the medical profession. Its derivation from the Latin audio implies listening rather than doing, passivity rather than an active endeavour to change. Its usage in the accountancy and business world implies external scrutiny of activity with the promise of corrective action, rather than a professional commitment to improvement. Perhaps it was adopted because early examples of the audit of medical care were externally organized reviews of hospital medical care provision, heavily concerned with examining the outcome of clinical care, rather than searching for an overall improvement in medical services. For example, the confidential enquiry into maternal deaths has been a long running—and successful— assessment of the clinical outcome of pregnancy, but with little concern for patient acceptability.
Medical audit and accountability
Authors: Metcalfe David
Published: November 2023

To be an independent contractor is not to be absolved of accountability. Doctors are paid to provide medical care, and many of the actions they take cost the NHS public money. Those who spend public money are accountable to Ministers in Parliament. In the case of primary health care this accountability is mediated through Family Health Service Authorities (FHSAs), who supervise contracts by monitoring claims for item of service or target achievement, prescribing activity from Prescribing Analysis and Cost (PACT), and now other activities from practice reports. This constitutes external performance review, and it enables FHSAs to make comparisons, both between practices and between any given practice and whatever it chooses to cite as the ‘norm’ or expected level of performance.
Preventive care: child surveillance and women’s health
Authors: Pierce Mary
Published: November 2023

The foundations of our current child health services lie in the dreadful mortality figures of the end of the last century. In 1900 in Nottingham 161 per 1000 children died within their first year of life. By 1922 a child welfare service had been started. In 1967 the Sheldon Report recommended a series of checks which have been repeated almost continuously since then (Sheldon Report 1967). The Royal College of General Practitioners report Healthier children—thinking prevention strongly advocated the early integration of developmental surveillance into general practice (Royal College of General Practitioners 1982). In 1989 a review of child health surveillance Health for all children (Hall 1990, 2nd edn) critically appraised current activities and made recommendations as to whether practices should be continued or discontinued.
Prescribing and formularies
Authors: Reilly Philip
Published: November 2023

There is no longer any doubt that audits of general practice prescribing in the UK will happen. The introduction of an indicative prescribing budget for each practice means that a crude form of external audit of prescribing is now in place. In such monitoring, cost is, of course, an immediate and important concern. The steeply rising expenditure on medications over recent years ensured that cost above all else would be considered in the health service reforms as they affect prescribing. UK prescribers are parsimonious in comparison to other similarly developed countries, but the large variation in the cost and frequency of prescribing by practices which were otherwise similar has interested the Government, which naturally sees the financial advantages of all practices behaving in the same way as the cheapest. The fact that such variations were and remain difficult to explain is only now being addressed. Little in medical education prepares the doctor for prescribing in general practice. Young doctors have been thoroughly prepared theoretically and pharmacologically, but are unprepared either for the range of pathology or for some of the apparently irrational pressures to prescribe which occur in primary health care. Many older doctors fail to stay in touch with the rapidly changing field of modern therapeutics.
Problem-solving audits
Authors: Lawrence Martin
Published: November 2023

‘Problems’, writes Baker (1990), ‘can be thought of as deficiencies that those in the practice think are so important that corrective action must be taken’. He goes on to express the view that audits done in response to acknowledged problems usually result in change, those done for curiosity or under compulsion are less likely to do so. Since the prime aim of audit is to improve care, this implies that problem-solving audits are likely to be the most fruitful. Significant event analysis and problem solving have a great deal in common. The former can be construed as formal review of a specific incident, seeking changes which might enable a similar situation to be handled better in future; the latter as an investigation set up to analyse a problem—which may indeed have been revealed by an event.
Access, availability, and continuity
Authors: Freeman George
Published: November 2023

General practice should offer both accessibility and continuity. The patient should find it an easy matter to see the doctor or other primary care team member at a convenient time. Care should be as continuous as required, that is consistent and uninterrupted. Since so much of general practice is based on interpersonal relationships, continuity tends to mean seeing the same person—any alternative implies a very high degree of communication between members of the care team, including the keeping of excellent records. In the archetypal single-handed practice the practitioner was available for long hours and access was by corning and queuing. The patients always saw the same person, so continuity was only limited by the doctor’s memory. Nowadays doctors work in groups with paramedical colleagues. Availability is negotiated through receptionists who operate an appointments system for most contacts with health team members. Although this was originally an attempt to eliminate queuing, appointments systems are also used to even out demand over a number of consulting sessions. The effect may limit both availability and continuity.
Assessment of patients’ views in primary care
Authors: Fitzpatrick Ray
Published: November 2023

The new contract requires family practitioner committees to carry out surveys to assess patients’ views of their general practice services. At the same time it is now expected that patients’ views should be included in medical audit in primary care. This chapter considers some of the methods involved. Whilst indicating the potential value and scope of consumer surveys, the chapter also discusses the potential pitfalls and problems that are frequently encountered. First, it is important briefly to clarify the different reasons why the importance of patients’ views has been so much emphasized in recent policy documents about the health service. One factor is the growing acceptance that the patient provides an important indicator of the quality of care. Indeed, in many aspects of primary care, such as the accessibility of the practice, the receptionist’s manner, or the availability of out of hours care, the patient’s views may be one of the main indicators of quality.
The same equations, different model
Authors: Cruickshank Steven
Published: November 2023

The gas laws are empirically derived descriptions of the behaviour of real gases, They are only approximately true for real gases and the laws break down seriously at extremes of temperature and pressure, They can be explained in terms of the kinetic theory of gases and thermodynamics, and modifications of the fundamental model have been made to improve the correspondence with reality; for exam,, ple, Van der Waals’ equation. The purpose of introducing them here is that they give rise to a model which is identical to that which we have just developed from first principles in describing the relationship of VA and Paco2.
Q by dye-dilution
Authors: Cruickshank Steven
Published: November 2023

The Fick methods for cardiac output determination involving 02 uptake and CO2 output are clearly steady state methods. The universally applied method in clinical practice now is thermodilution using a cardiac output computer. This is a development of the older dye-dilution method in which a dye is injected rapidly into the pulmonary artery and its concentration in blood drawn intermittently from a peripheral artery over the ensuring minute or so is determined. Alternatively, blood was drawn at constant rate from the artery and passed through a densitometer charnber. A typical (simulated) record of the dye-dilution method is shown and it is evident that dye concentration is not in steady state.
The Kety-Schmidt method for cerebral blood flow (CBF)
Authors: Cruickshank Steven
Published: November 2023

The measurement of cerebral blood flow (CBF) is accomplished using the same flux principles as cardiac output. The classical method is that of Kety and Schmidt, using N2O uptake into the brain. More modern methods using radioactive isotopes such as Xenon are merely modifications of the earlier method. The fluxoid idea should make this easy to understand.
Pre-oxygenation: washing out the nitrogen
Authors: Cruickshank Steven
Published: November 2023

As we have already seen, the technique of pre-oxygenation can be of literally vital importance. The process involves replacing the nitrogen in the lung with oxygen so that the oxygen store is augmented, and we have already seen the effectiveness of this. But how rapidly do we expect to be able to achieve the replacement of nitrogen with oxygen? We can model this as an extension of the models that we have already encountered. Although details of technique (e.g. the ability to maintain an air-tight seal with a face mask) will have an important influence, it is useful to have a semi-quantitative idea of how rapidly changes in concentration occur under ideal conditions. This turns out to be a simple matter requiring only application of a ‘rule of thumb’ (and some mild mental arithmetic) if the underlying processes are understood; and, very importantly, the ideas are transferable to many other analogous circumstances.
Standardizing the rate
Authors: Cruickshank Steven
Published: November 2023

The rate of the exponential process in the N2 washout was determined entirely by the ratio of flow ( VA) to volume ( VFRC). No other factors are important in the simple model. We can standardize any simple wash-in or washout exponential process in which there is a flow Q into a container of volume V, by a device, the time constant T. The time constant is the time required for the flow to fill the container. What constitutes the flow and what the container is will vary from circumstance to circumstance, but the principle remains intact. The time constant enables us to use a ‘rule of thumb’ to estimate the magnitude of the change that has occurred.
Invasive blood pressure measurement
Authors: Cruickshank Steven
Published: November 2023

We have spent some time modelling naturally oscillating systems, and we have seen how they respond to a displacement from their equilibrium position in the face of various levels of damping. We now need to look at how such systems respond to an applied vibration from outside. We will concentrate on the implications for invasive blood pressure measurement, but there are many circumstances in which we apply an oscillating force to a real system-high-frequency ventilation is another example.
Constant function
Authors: Cruickshank Steven
Published: November 2023

This is the graph of a function whatever TCP we choose, the graph gives a (constant) unique value for the CSF production. The reality of control of CSF flow will, of course, be more complex. The rule for a constant A function may have different rules for different parts of its input. The CSF uptake is modelled as constant for part of its input and by a linear function for the rest. CSF uptake is a variable. We shall see plenty of examples of the use of constants. Often, these will be constant functions of time. By definition modelling of steady states produces constant functions with respect to time. Other quantities are constant only under specified conditions:
Rectangular hyperbolic functions
Authors: Cruickshank Steven
Published: November 2023

The rectangular hyperbola is a function that very commonly arises in modelling. We shall again look at the basic function and then transform it to other related functions by simple manoeuvres. We shall concentrate our attention on transformations as they affect the graph in the first quadrant (x and y both positive).
Differential equations
Authors: Cruickshank Steven
Published: November 2023

Most differential equations which arise in science and engineering are actually insoluble by other than numerical methods. General methods of solution to some classes of differential equation are available, but are beyond our scope; we shall be content to show how the differential equation and solution functions from some of our examples are related.
Numerical methods for differential equations
Authors: Cruickshank Steven
Published: November 2023

We have studied some models which have given us ODEs that we have been able to solve. ‘Solve’ here means we were able to find a function the rate of change of which is given by the ODE. We cannot always find a function that satisfies the ODE and the pulmonary air embolism (1.12) problem was an example of this; the problem was real enough, and we would like to know the solution-but we cannot find one. All is not lost, however; if we know the rate of change (from the ODE) and a starting value (an initial condition), we can produce an approximate graph of the function that we require. We demonstrate this with a known uncomplicated function, so that we can compare the real and approximate solution.
Probability models and simulation
Authors: Cruickshank Steven
Published: November 2023

Probability distributions are functions and are used as models for problems involving random processes in exactly the same way as the other functions in the deterministic physiological models that we have developed. Just as we saw certain patterns arising in the physiological modelling, in probabilistic models certain patterns turn up frequently. Modelling assumptions are made which lead to probability models. These can then be used to make rational decisions about proble111s in which chance plays a part, or to make estimates of quantities with defined levels of certainty.
Waiting times in a Poisson process
Authors: Cruickshank Steven
Published: November 2023

We are beginning to feel more familiar with Poisson processes, so let us stay with them a little longer but look now at a different aspect. If we return yet again to the anaphylaxis example, we might ask how long we would expect to wait between one reaction and the next. Again it is simple to state that, since the expected number annually is five, then we expect to wait 0.2 years-about 73 days on average. Since the process is random, however, we know that there will be a spread of waiting times. We have exactly the same circumstance, but we are asking a different question about the situation. Whereas previously we were counting events in a given time, now we are measuring times between those same events. The distinction between counting and measuring is an important one.
Passing the fellowship examination
Authors: Cruickshank Steven
Published: November 2023

Suppose that we have eight candidates taking the fellowship exam and there is a published pass rate of about 30%. Each individual’s exam is a ‘trial’ and passing the test is a ‘success’. ‘Success’ and ‘trial’ are technical terms in probability theory and are obviously very appropriate here. We suppose that one candidate’s success is independent of another’s-no cheating. We expect 2.4 candidates to pass, but obviously the realization will be different-only a whole number can pass. We would probably say that two was the most likely number, since this is the integer closest to 2.4.
Measuring SVP: the normal distribution
Authors: Cruickshank Steven
Published: November 2023

A pharmaceutical manufacturer has produced a new volatile anaesthetic agent and, in order to deliver it by vaporizer, needs to establish a value for the saturated vapour pressure (SVP) at 20°C. The SVP of a substance at any fixed temperature is a physical constant-it has no inherent variability. Unfortunately, the measurement method itself is subject to error, and even though the laboratory might control the experimental conditions as well as possible, there is always some variability in the measurement. The manufacturer has been using the same method for a long while, and knows that on average 95% of the SVP measurements fall within 8 mmHg to either side of the mean value.
Modelling with random variables
Authors: Cruickshank Steven
Published: November 2023

We have seen examples of a number of situations in which random factors are operating and we have introduced four different patterns of variability-the Poisson, exponential, binomial, and normal distributions. These distributions are expressions of the behaviour of probability models. The real-life examples have all been typical random variables. A random variable (RV) is simply any quantity that varies according to some random process, and our first task is to choose an appropriate probability model to parallel the real situation, if we can. Sometimes this is easy-the result of the throw of a fair die calls for a very simple model-but some times it is impossible to produce a plausible probability model.
Sums and differences of random variables (RVs)
Authors: Cruickshank Steven
Published: November 2023

The die is an example of the uniform distribution which is almost as simple as a distribution can get. But if our RV is the sum of two throws of a die, what distribution do we get then? The range of outcomes is now 2, 3, … , 12, but is the distribution still uniform? Each throw of the die is independent and each possible combination-six for the first throw and six for the second-occur with equal probability; 36 possibilities in all.
Conditional probability and Bayes’ theorem
Authors: Cruickshank Steven
Published: November 2023

We have now encountered the idea of a conditional probability, where the test result is conditional on the presence or absence of a condition-here difficulty in intubation, D. Before we perform a test, there is a probability of D, p(D), which is dependent upon the extent of prior information. If the patient is unselected, then p(D) is that of the prevalence in the general population, 2%. If we already know that the patient has ankylosing spondylitis,
The normal distribution
Authors: Cruickshank Steven
Published: November 2023

It seems to be true that, however little students know about probability and statistics, they will be familiar with the essential features of the ‘bell-shaped’ normal distribution. The normal distribution made a short appearance as a model of measurement error when we were considering estimation of the SVP of a new anaesthetic agent (3.5.1). This model was essentially an empirical one, in that the pattern of measurement error had the same ‘shape’ as the normal.
Statistical inference
Authors: Cruickshank Steven
Published: November 2023

Two key concepts that we shall need repeatedly are those of population and sample. A population may be some circumscribed group-the number of children under eight years admitted to a particular ITU in in a particular year, for example-or some more abstract collection. In the anaphylactoid reaction example, the random variable was the observed number of severe reactions annually. The observed values of the RV form a sample from all the possible observations that we might make-the population. Although we can actually only make a limited number of observations, we view these observations as arising from some larger collection, the population. It is usually quite clear what the population comprises in any given problem.
Sample mean
Authors: Cruickshank Steven
Published: November 2023

We shall simply mean the larger possibly infinite group of possible observations from which our actual ones are drawn. The distribution of the population is called the parent distribution-the samples are its children, in a sense. The samples are then used to calculate measures-statistics-which have related but distinct distributions. These are the sampling distributions of the statistics.
Sample variance
Authors: Cruickshank Steven
Published: November 2023

The SVP example was quite easy to deal with because the manufacturer knew the precision of the measurement method, a-= 4 mmHg; he was attempting to determine the unknown mean of a normal distribution of known variance. If he had no information on the value of a-, then he could still make a point estimate ofμ from the sample mean x, but he could not quote a CI because he would need to know the precision a- to calculate the SEM (3.13.2). Such prior knowledge of the variability of the parent population is very unusual indeed in practical studies; it is far more common to have no information about either mean or variance.
Significance testing
Authors: Cruickshank Steven
Published: November 2023

Suppose that we are investigating the release of a plasma peptide after administration of an intravenous induction agent. We have a sample of ten patients and for each we have a pre-administration and a post-administration plasma peptide level. Thus we have a collection of ten data pairs. How can we decide whether there is evidence of release of the peptide by the agent? We shall see later one method-the paired t-test (3.16.3) but first let us look at the simulated data with a rough and ready method-the sign test. This demonstrates all of the important features of significance testing in a simple setting.
Categorical data
Authors: Cruickshank Steven
Published: November 2023

Suppose that we have a new intravenous anaesthetic agent Zapidate. This causes pain on injection in some patients and an investigation is conducted to examine the effect of the addition of local anaesthetic, ‘Wondercaine’, on the incidence of this. 261 patients are randomly allocated to one of two groups to receive Zapidate with or without addition of Wondercaine. We count the number of patients who experience pain on injection in each of the two groups. Suppose that the incidence of pain is lower in the Wondercaine group. How do we decide whether the effect of Wondercaine is significant?
Related variables: correlation
Authors: Cruickshank Steven
Published: November 2023

The Paco2 regression on duration of apnoea is an example in which it is clear that the response variable is dependent upon the predictor variable and not the other way round; we know that time is independent of Paco2 There are many circumstances in which variables are related but the predictor/response relation is less clear. For instance, we know that tall people tend to have larger feet than short people, so that knowledge of height enables us to predict shoe size better than if we have no information on height. The concept of correlation is based upon the ability to predict from one variable to another in a similar way to regression but where we may have no way of independently controlling a ‘predictor’ variable-the related variable is itself normally distributed.
Distribution-free methods
Authors: Cruickshank Steven
Published: November 2023

Imagine that we are conducting a study to compare the effectiveness of two analgesics in pain relief after minor surgery. Suppose that we have randomly allocated seven patients to two groups; three to receive drug A and four to dnig B. Pain relief can be measured by asking patients to use an analogue pain score. It is not obvious how results of individual pain scores might be distributed, so we will use a technique which does not make any assumptions about the distributional origin of the data. Since we have no postulated distribution, we shall not be able to estimate parameters, but we can decide whether there is evidence of a difference in the effectiveness of the two analgesics. Of course, with such pathetically small numbers, we could not reach any very firm conclusions, but we can more easily see how the test works.
Reference intakes, dietary goals and nutrition labelling of foods
Authors: Bender David A , Bender Arnold E
Published: November 2023

There is a 20-30 per cent range of individual variation around the mean requirement for most nutrients. For the planning of diets for populations, specific groups of the population or institutions, it is necessary to ensure that the intakes of nutrients provided are sufficient to ensure that no-one suffers deficiency or inadequacy. For any parameter that is statistically normally distributed, a range of ± 2SD around the mean includes 95 per cent of the values. Although there is little evidence, it is generally assumed that individual nutrient requirements are normally distributed around the mean-the only nutrient for which there is clear evidence that this is not so is iron, which shows a markedly skewed distribution of requirements (see section 24.2). Therefore, an appropriate level of intake for all nutrients, but not for energy, is considered to be 2 standard deviations above the mean requirement, as determined experimentally. Because energy intake in excess of requirements to meet expenditure leads to the development of obesity (see Chapter 11), appropriate levels of energy intake are considered to be the mean requirement, not a level 2 x SD above the mean.
Carbohydrates
Authors: Bender David A , Bender Arnold E
Published: November 2023

Carbohydrates provide some 35-45 per cent of the energy intake in most developed countries, with a desirable level of intake being 55 per cent of energy, to compensate for the desirable reduction in fat intake (see section 4.2); in less developed countries carbohydrate may provide as much as 75 per cent of energy intake. Average and desirable levels of carbohydrate intake are shown in Table 7.1, and major sources in the average diet in Table 7.2.
Alcohol and alcoholic beverages
Authors: Bender David A , Bender Arnold E
Published: November 2023

Alcoholic beverages, made by fermenting fruit juices, sugars and other fermentable carbohydrates with yeast to form alcohol, have a long history, and are widely consumed in most countries, except where religious observance prohibits their consumption. Moderate consumption of alcohol is associated with lower mortality from cardiovascular disease, but persistent heavy consumption is associated with physiological addiction-alcoholism. In addition to the addiction, there may be damage to the liver (cirrhosis), stomach (gastritis) and pancreas (pancreatitis), as well as behavioural changes and peripheral nerve damage. Both general malnutrition and more specifically deficiency of thiamin (see section 17.5.5), niacin (see section 19.5), and zinc (see section 25.26.2) are associated with alcoholism.
Vitamin E and selenium
Authors: Bender David A , Bender Arnold E
Published: November 2023

Unlike the other vitamins, vitamin E seems not to have a specific enzymic function; rather it is the major lipid-soluble, free radical-trapping antioxidant in membranes, and many of its functions can be met by synthetic antioxidants. However, some of the effects of vitamin E deficiency in experimental animals do not respond to synthetic antioxidants. The metabolic roles of vitamin E and the trace element selenium are closely related, and to a very great extent each can compensate for a deficiency of the other. The sulphur amino acids (methionine and cysteine) also have a vitamin Esparing effect.
Vitamin K
Authors: Bender David A , Bender Arnold E
Published: November 2023

Vitamin K was originally discovered as a result of a haemorrhagic disease in cattle fed on silage made from sweet clover, and chickens fed on solventextracted fat-free diets. The problem in the chickens was a lack of the vitamin in the diet, while in the cattle it was due to the presence of dicoumarol, which is an anti-metabolite of vitamin K. It soon became apparent that vitamin K was required for the synthesis of several of the proteins required for blood clotting. It was only in 1974 (Stenflo et al 1974) that the metabolic role of vitamin K was elucidated, when γ-carboxyglutamate (often abbreviated to Gla) was found to be present in the vitamin K-dependent proteins, but absent from the abnormal precursors which circulate in deficiency. γ-Carboxyglutamate is chemically unstable, and undergoes spontaneous decarboxylation to glutamate under the conditions traditionally used for protein hydrolysis and amino acid analysis.
Riboflavin (vitamin B2>
Authors: Bender David A , Bender Arnold E
Published: November 2023

Riboflavin has a central role as a redox cofactor in energy-yielding metabolism. Dietary deficiency is relativly widespread, yet is apparently never fatal; there 1s not even a clearly characteristic riboflavin deficiency disease. This does not seem to be the result of intestinal bacterial synthesis of the vitamin rather there is very efficient conservation and reutilization of riboflavin in tissues in deficiency. Riboflavin coenzymes are tightly enzyme bound, in some cases covalently, and control of tissue flavins is largely at the level of synthesis and catabolism of flavin-dependent enzymes.
Ectopic pregnancy: imaging and modern concepts of management
Authors: Cacciatore Bruno
Published: November 2023

The clinical spectrum of ectopic pregnancy has changed dramatically in recent years. The incidence has risen sharply due to not only an increasing incidence of risk factors for this condition, such as pelvic inflammatory disease, use of an intrauterine contraceptive device, pelvic operations, and tubal surgery, but also to improved detection of ectopic pregnancies which might have gone unrecognized in the past (Makinen 1988). The mortality rate, as well as the frequency of tubal rupture and other severe complications, have decreased concomitantly, thanks to improved diagnostic modalities. The major clinical concern now is poor reproductive performance following ectopic pregnancy. Only about half of affected patients will conceive again, with a risk of a second ectopic pregnancy of 10-20% (Stabile and Grudzinskas 1990).
Amniotic fluid volume disorders: diagnosis and therapeutic approaches
Authors: Ahn Myoung Ock , Phelan Jeffrey P
Published: November 2023

For centuries, amniotic fluid has been presumed to serve as nourishment for the developing fetus (Denman 1815). With a greater understanding of amniotic fluid dynamics, (Hellman and Pritchard 1971; Lind et al. 1972; Seeds 1980; Queenan 1990), this concept has been discounted. For example, the accumulation of amniotic fluid provides a medium in which the fetus can readily move. At the same time, this fluid acts as a cushion to protect the fetus from the risk of limb and facial malformations and from possible cord compression during fetal activity or uterine contractions. In addition, it is a means of maintaining euthermia. But most of all, fetal status appears to be correlated with the quantity of amniotic fluid.
Symposium: clinical trials of obstetric ultrasound
Authors: Duley Lelia
Published: November 2023

Pregnancy, childbirth, and the neonatal period are physiological events, not illnesses. Yet, most women having children in Western Europe and North America attend the health services for antenatal and intrapartum care. One reason for this remarkable compliance is that, regardless of their health or social status, women believe the care they receive will improve the outcome for themselves and for their child. Given that they have been encouraged in this belief by those who provide care, the onus is on the care givers to ensure that they do more good than harm.
The aims of the curriculum: education for health needs in 2000 and beyond
Authors: Towle Angela
Published: November 2023

In recent years, a variety of sources—government, foundations, educators, the media, and, perhaps most importantly, those who use medical care—have begun to focus on what is required to produce a good physician. Both internal and external forces are encouraging medical schools to alter their curricula and even their basic structure. Accrediting bodies have imposed new standards that call for measuring and evaluating medical school graduates according to a variety of educational outcomes. In some instances, funding has been coupled with the attainment of mandated outcome objectives (Jonas et al. 1992).
Opportunities outside hospitals
Authors: Field Jenny
Published: November 2023

Doctors of the future must provide health care which is responsive to the needs of all the people in the region which they serve. Medical students, who will become those doctors, are traditionally trained in hospitals, concentrating on the needs of a much smaller and sicker part of this population. The tension created here has been most clearly recognized in parts of the world where there is a major disparity between the provision of high technology care in hospitals and the priority health care needs of much of the population, which may lie mainly in primary care. In the United Kingdom appreciation of this same tension has been precipitated by recent changes in the delivery of health care. The revolution in the provision of care, involving minimally invasive surgery and investigations, shorter hospital stays for acute disease, and the transfer of care for many chronic diseases into general practice means that patients in hospital are even fewer and sicker than before. In order to deliver a curriculum which can prepare doctors to care for the health needs of all, students must be given opportunities to learn where all types and severity of disease present and are managed, that is, both inside and outside hospitals.
Assessment
Authors: Newbie David
Published: November 2023

It is impossible to overestimate the importance of assessment. Involvement of teachers in developing assessment procedures is almost certainly the most critical educational task they will undertake. The methods they select and the content they include will have profound effects not only on what students learn but also on how students learn. Yet, in many institutions, assessment practices misdirect student learning activities in ways that may seriously undermine the aims of the curriculum. In addition, the organization and preparation of undergraduate examinations are often left to junior members of staff who have neither the experience, training, resources, nor the authority to produce tests of high quality. In the process of curriculum or course review, assessment is frequently something which is little more than an afterthought, following detailed consideration of the aims, objectives, teaching methods, and timetabling.
Clinical work and teaching
Authors: Dacre Jane
Published: November 2023

Most working doctors teach. In a ‘teaching’ hospital environment, there is an increased emphasis on this and, indeed, the Trust is paid a sum of money (service increment for teaching, SIFT) to allow teaching to continue. However, there are problems related to the career development of junior doctors. At the moment, progress through the medical ranks is based more on a doctor’s research output than their teaching ability or experience. Promotions and appointments are biased towards candidates with a large number of publications on their curriculum vitae. There is no recognition of teaching other than in an informal way within each medical school (Dacre et al. 1996) The financial support given to an academic department by the local university is based on the number of papers produced, and the number of grants awarded to that department. This kind of assessment reduces the priority given to student teaching, Departments with a poor teaching record (at least as far as students are concerned) are often those that concentrate their efforts in research areas, and so generate a high income for the medical school. This difficulty has been appreciated by many medical colleges, but the system is still pervasive and biases academic departments against putting significant resources into their teaching programmes.