Learning outcomes By the end of this unit you should be able to: summarise and identify descriptions of the principal features of the main lithotectonic units of the British Isles, namely the Precambrian Basement, the Caledonian Orogenic Belt, the Variscan Orogenic Belt, the Older Cover and the Younger Cover; identify any of the main terranes making up the British Isles on the basis of a description of its age, main rock types, dominant structures, and plate tectonic setting.
3.7 Moon39: Apollo 14 station C The panorama was collected by Alan Shepard at station C-Prime. (QuickTime, 500KB, note: this may take some time to download depending on your connection speed) 2.4 The atmosphere and polar ice David A. Rothery Teach Yourself Planets, Chapter 6, pp. 66–75, Hodder Education, 2000, 2003. Copyright © David Rothery The Moon's atmosphere is almost as insubstantial as Mercury's, and probably has much the same origin. The Clementine mission returned our first clear views of the lunar poles, showing sites in particular near the south pole that are permanently in shadow, and which could therefore be places where ice might accumulate (Figure 1). Clementine' 4 Neural processing of auditory information In this section we will look at how the frequency selectivity found along the basilar membrane is preserved or modified by the auditory nerve and how information about the intensity of the signal is encoded in the response of the auditory nerve fibres. The nerve that communicates with or innervates the hair cells along the basilar membrane is called the vestibulocochlear nerve or VIIIth cranial nerve. It enters the brainstem just under the cerebellum and conveys information from 3.8 Revision questions Discuss the two ways in which the middle ear increases the effectiveness with which sound is transmitted from the external ear to the inner ear. 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 2.6.1 Unit summary Laws summarise regularities observed in Nature. They can summarise large numbers of similar phenomena and make it possible to predict the course of particular phenomena. In physics, many of the laws are expressed mathematically and concern measurable quantities. This aids precision and clarity, and it supports rational argument. Newtonian mechanics is based on equations (Newton's laws of motion, Newton's law of universal gr 2.5.3 The end of physics? Suppose for the moment that quantum field theory, or string theory or M-theory, or some other theory no one has yet heard of, does turn out to be the much sought-after superunified theory. Suppose it is unique and is so wonderfully compact that it can be printed on the front of a T-shirt. What would such a theory really tell us about the world? Looking on the positive side, the theory should indicate the fundamental entities of which the world is composed, whether they are particles, st 2.5.1 Quantum mechanics and chance The real quantum revolution dates from the formulation of quantum mechanics by Werner Heisenberg (1901–1976) and others in 1925, and its physical interpretation by Max Born (1882–1970) in 1926. However, before attempting even the most basic sketch of quantum mechanics let's take a small diversion into the realm of philosophy. The basic working philosophy of most scientists, including those who say they have no philosophy, is a kind of realism. (Philosophers recognise m 2.3.2 Equilibrium and irreversibility As the science of thermodynamics developed beyond its industrial roots, two powerful ideas came to the fore – equilibrium
and irreversibility. These ideas were already implicit in studies of heat. You have already seen that heat flow from a hot steak to a cold plate is an irreversible process. The effect of this process is to cool down the hot steak and warm up the cold plate, leading to a more uniform distribution of temperature. The heat transfer continues until a state of e 5.2.1 The GM Science Review The review was undertaken by the GM Science Review Panel, chaired by the Government's Chief Scientific Adviser, Sir David King. Its role was to assess the evidence available in the peer-reviewed scientific literature. The panel produced two reports, the first in July 2003 and the second in January 2004. The main conclusions of these reports are listed below. The risk to human health is very low. There is little likelihood of such plan 3.3 Drawing conclusions Sections 2.1 and 2.2 have summarised some of the major aspects of the Pusztai affair, but it should be said that almost every detail has been the subject of prolonged and heated dispute. Our purpose is not to attempt to denigrate individuals or institutions. Rather, the hope is that the tale carries some general messages of value about how science is undertaken and communicated, which can sometimes become clearer when things go wrong. Communicating preliminary scientific information via References 2.5.1 Summary of Section 2 Desert animals are classified in terms of their body size and physiology into three groups: evaders, evaporators and endurers. The logic for this classification is that the smaller the animal, the larger its surface area to volume ratio. Small animals therefore gain and lose heat faster than large animals, warming rapidly when exposed to intense solar radiation, and cooling rapidly at night. Small endothermic evaders, e.g. kangaroo rats, rest in cool microenvironments, e.g. shade or burrows, References 2.2 Species showing torpor or deep hibernation Among the birds, torpor occurs in a number of species in the orders Apodiformes (hummingbirds and swifts), Caprimulgiformes (nightjars, nighthawks, goatsuckers and poor wills) and Coliiformes (mousebirds). In all of the hummingbirds (family Trochilidae) studied to date, torpor, if it occurs, takes place on a daily (or more usually nightly) basis. They are able to re-warm themselves independently of T
a and show an increased thermogenesis if T
a falls below 5.4.1 Summary of Section 5 Several anatomical and biochemical adaptations to living in very cold water have evolved in polar fish, particularly those of the southern oceans, which have evolved in isolation for many millions of years. Cold, turbulent water is rich in oxygen. One family of fairly large fish lacks blood pigments but its blood is less viscous and it has additional respiratory surfaces. Many fish have cryoprotectants in the blood and other body fluids, and the muscles of some contain numerous mitochondria a 5.4 Fatty acids as indicators of diet Although polar fish and invertebrates are difficult to study alive for the reasons just described, some information about their diet and habits can be obtained from analysis of the lipid composition of their tissues. At high latitudes, the supply of most kinds of marine food changes with the seasons, just as it does on land, and many fish eat little or nothing for long periods, living off their reserves of triacylglycerols. Lipids are major fuels for polar fish and, although many fish have li 4.3 Humans in polar regions Humans evolved in tropical Africa and gradually colonized colder climates during the Pleistocene ice ages. There have been permanent populations in the Arctic for several thousand years, mostly Inuit (Eskimos) in what are now Canada, Alaska and Greenland, and several groups in northern Europe and Russia, such as the Saami (Lapp) in Scandinavia and the Chukchi in Siberia. Such people do not grow crops and keep only a few domestic animals, mostly for transport (e.g. husky dogs or reindeer), not 3.1 Introduction It is clear from Sections 1 and 2 that seasonal or irregular periods of fasting are an integral part of living at high latitudes, especially for large animals. When people (and many tropical and temperate-zone mammals) lose weight, either because they are eating less or because they are suffering from a digestive or metabolic disorder, protein is broken down in substantial quantities long before the lipid stores are exhausted. Even frequent and vigorous exercise cannot prevent the breakdown o
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