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This chapter tests the traditional appreciation of farming in the past, based on crop rotations of two or three crops followed by a fallow year, against the evidence-based practice of 18th- and 19th-century farmers. Not only was farming more complex than this, but it also changed and therefore evolved according to farmers' assessments of the market and the diffusion of new crops and techniques. Through measurements derived from farmers' records, the magnitude of this evolution is measured and in particular the temporal diffusion of the Norfolk four course systems of new crops based on the nitrogen cycle is assessed. At the same time, there was a revolution taking place in soil improvements through soil conditioning and fertilizing, and these are also measured and assessed.

As has been emphasized throughout this book, minimum intervention oral/dental care involves more than just the minimally invasive operative treatment of the consequences of dental disease. It involves identifying and predicting disease patterns, and concerns the control/ prevention of disease by modifying aetiological factors and reassessing the adherence to changes in patient behaviours, attitudes, and responsibility. Monitoring the oral cavity and restored dentition ensures that the treatment undertaken, and subsequently improved oral health, is maintained. This should be accomplished through individualized strategic recall regimes. Restorations need to be reviewed regularly and occasionally refurbished, resealed, repaired, or replaced (see Figures 9.1, 9.2, and 9.3, and Section 9.5). Therefore periodic recall appointments, once an episode of treatment has been completed, are just as important as the treatment itself. It is critical that the patient understands the importance of these recall consultations as part of the ongoing care that is being offered to help to maintain their oral health. Three aspects of dental care need to be assessed at recall visits:… • the overall state of the patient’s oral and dental health (review) • the individual patient’s longer-term response/adherence to previous preventive advice and/or treatment, in moderating any aetiological factors that could cause future dental disease (reassessment) • the status and quality of the restorations present (monitoring and maintenance)…. The potential causes of restoration failure have been identified and outlined in Table 9.1. It is important to appreciate that the causes of restoration and tooth failure (see Table 9.2) are often multifactorial in nature. Indeed, as the causes of both tooth and restoration failure are inextricably linked, it is wise to consider them together, as a tooth–restoration complex. The multifactorial aetiology of restoration failure is often due to manifestations of inherent long-term weaknesses in the mechanical properties of different restorative materials (e.g. poor edge strength, wear, compressive strength, water absorption, etc.) and/or problems with the technical application of the restorative material for the chosen clinical situation (i.e. incorrect choice of material and poor placement technique). The chemistry and physical properties of the different direct, plastic restorative dental materials at a dentist’s disposal have been discussed in Chapter 7.

This chapter discusses reversible, irreversible, and quasi-static thermodynamic processes. Heat engines, refrigerators, air conditioners, and heat pumps are analysed and their optimal efficiencies are calculated.

Most of the energy used by buildings goes into heating and cooling. For small buildings, such as houses, heat transfer by conduction through the sides is as much as, if not greater than, the heat transfer from air exchanges with the outside. For large buildings, such as offices and factories, the greater volume-to-surface ratio means that air exchanges are more significant. Lights, people and equipment can make significant contributions. Since the energy used depends on the difference in temperature between the inside and the outside, local climate is the most important factor that determines energy use. If heating is required, it is usually more efficient to use a heat pump than to directly burn a fossil fuel. Using diffuse daylight is always more energy efficient than lighting up a room with artificial lights, although this will set a limit on the size of buildings.