bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative Genetics And Reaction Norms
Authors: Stearns Stephen C
Published: November 2023

Whereas demography analyses the phenotypic sources of variation in fitness that produce natural selection, quantitative genetics and reaction norms are used to analyse the genetic variation that conditions the response to selection-how much there is, how it is maintained, and how it is expressed. This chapter introduces the aspects of quantitative genetics and reaction norms needed to analyse the microevolution of life history traits. Heritability and genetic covariance are defined and methods for measuring them are discussed. The heritabilities of fitness components should be lower than the heritabilities of other traits-and they are-but considerable genetic variation for life history traits is maintained in nature. Five explanations for the maintenance of genetic variation in fitness components are discussed: mutation-selection balance, genotype by environment interactions in heterogeneous environments, negative genetic covariance, gene flow, and flat fitness profiles.
Age And Size At Maturity
Authors: Stearns Stephen C
Published: November 2023

This chapter analyses the evolution of age and size at maturity. Maturation divides a life into preparation and fulfilment. Age at maturity is pivotal, for fitness is often more sensitive to changes in this trait than tq changes in any other. With maturation, selection pressures and trade¬ offs change dramatically. The microevolutionary selection pressures and trade-offs are sketched in the introduction. The demographic pressure to mature early must be balanced by trade-offs with other fitness components to explain delayed maturity. The second section documents variation in age and size at maturity among and within vertebrate classes, among and within populations of single species, and between the two sexes. Species that delay maturity tend to be large, long-lived, and, if they are birds or mammals, to have a few, large offspring, or, if they are reptiles, to have many, small offspring. Much of this pattern is associated with higher taxonomic levels; it weakens but does not disappear within populations.
General introduction
Authors: Patterson David J , Larsen Jacob
Published: November 2023

With the widespread acceptance of the importance of microbial food webs, heterotrophic flagellates have become a focus of attention as principal consumers in many aquatic ecosystems. There is currently no satisfactory account of the diversity or biology of these organisms. Studies on their ecology and taxonomy need to be woven together before we can understand the diversity and nature of the transactions conducted by heterotrophic flagellates within microbial food webs, and in order to address the temporal, geographic, and physiological variations of microbial communities. This volume seeks to review our present understanding of the biology of these organisms.
The diversity of bodonids
Authors: Zhukov B F
Published: November 2023

Bodonids are biflagellated kinetoplastid flagellates, many of which are free-living. They are common and widespread in all kinds of aqueous environments. Species level taxonomy is very uncertain. This account deals with the genera Bodo, Cephalothamnium, Cryptobia, Dimastigella, Pleuromonas, Procryptobia, Parabodo, Rhynclwmonas, and ‘Rhynchobodo’
The Ultrastructural Organization of The Heterotrophic Euglenids and Its Evolutionary Implications
Authors: Triemer Richard E , Farmer Mark A
Published: November 2023

Although commonly thought of as photosynthetic, many euglenids are heterotrophic. Most osmotrophic forms inhabit freshwater while the phagotrophs can be freshwater or marine. This chapter describes the ultrastructural features of heterotrophic marine euglenids in the orders Sphenomonadales and Heteronematales (sensu Leedale). Comparison of the cytoskeleton, feeding apparatus, flagellar apparatus, and mitotic apparatus led us to the view that the euglenid ancestor was a phagotrophic biflagellate with an aplastic pellicle. As the euglenids evolved, the feeding apparatus was supported by an increasing number of microtubules and became capable of ingesting eukaryotic prey. Concomitant with this was the increase in the number of pellicle strips and the development of metaboly. It is argued that it was this form of euglenid with a plastic pellicle and large feeding apparatus which engulfed a photosynthetic cell and through endosymbiosis gave rise to the photosynthetic euglenids.
The structure of the starch polysaccharides and their organisation in the starch granule
Authors: Ring S G , Noel T R , Bull V J
Published: November 2023

Starch is the main reserve polysaccharide of higher plants, where it occurs as water-insoluble granules. The main structural features of the starch polysaccharides were determined many years ago. Using classical chemical techniques it was found that it was a (1→)-α-D-glucan containing a branch point, which was l→4→6 linked, for every 20 or so straight-chain residues. At about the same time it was found that starch was not a single polysaccharide, but a mixture of two main polysaccharides. One of these, amylose, is essentially linear; the other, amylopectin, highly branched. In this review we consider recent research on the structure of these polysaccharides and how they are organized in the starch granule. One aim of this chapter is to promote consideration of the relationship between the structure of the starch polysaccharides and their crystallization. For more extensive reviews the reader is referred to more detailed texts on the chemistry and physics of starch (Whistler et al. 1984; Banks and Greenwood 1975; Guilbot et al. 1985).
Biological and evolutionary aspects of cereal seed storage proteins
Authors: Shewry Peter R
Published: November 2023

Seed storage proteins have been the subject of a great deal of research, particularly over the last 10–15 years. The reasons for this are twofold. Firstly, seeds are the major plant organ harvested by humans, and their storage proteins are the main source of protein for human nutrition, livestock feed, and industrial raw material. Secondly, the high level of storage protein synthesis in developing seeds and its strict tissue specificity mean that storage proteins are an attractive system in which to study the control of gene expression.
Triacylglycerol biosynthesis
Authors: Stymne Sten , stobart A Keith
Published: November 2023

Plant triacylglycerols, commonly known as vegetable oils and fats, have many applications in the food and chemical industry and are a most important commodity in world trade. In the triacylglycerol molecule, one fatty acid residue is esterified to each of the three hydroxy groups of the glycerol backbone. The quality of the oil, and hence its end use, is determined by the fatty acid composition and, to some extent, the positional acyl distribution. All commercial annual oil crops have seed oils largely composed of the five major fatty acids, palmitic (16:0), stearic (18:0), oleic (18: lΔ), linoleic (18:2,1Δ12), and a-linolenic (18:3Δ12Δ15). These are the same ‘housekeeping’ fatty acids present in the membrane lipids of all plant cells. The fatty acid composition of membrane lipid in leaves and roots, however, is under strict control and differs little between plant species, whereas the relative abundance of a fatty acid in the storage triacylglycerols can show variations between different oil crops (Table 6.1). Although the natural variation in the fatty acid composition of oil-crop species gives a range of oil quality, there would nevertheless be several advantages if a species could be tailored to produce a ‘designer’ oil to suit a particular purpose.
Synthesis, targeting, and packaging of wheat seed storage proteins
Authors: Galili G , Levanony H , Rubin R , Giorini-silfen S , Rosenberg N , Shani N , Altschuler Y , Shimoni Y , Karchi H
Published: November 2023

Wheat storage proteins are synthesized in the endosperm and accumulate intracellularly in protein bodies (Shotwell and Larkins 1988). The major wheat storage proteins are the alcohol-soluble gliadins and the glutenins. The gliadins are monomeric proteins that migrate between 30 and 60 kDa on SDS-PAGE and are subdivided into a, P, y and co-gliadins on the basis of fractionation on acidic PAGE (Woychik et al. 1961). A new classification of gliadins into sulfur-rich (a, p, y) and sulfur-poor (co) fractions has been suggested (Kreis et al. 1985), based on their amino acid sequence and sulfur content. Glutenins aggregate by disulfide and non-covalent bonds to form large complexes, but reduction and subsequent electrophoresis indicate that these proteins are comprised of two groups of low- and high-molecular-weight glutenin subunits (LMW-GS and HMW-GS) (Khan and Bushuk 1979). The LMW-GS are similar in Mr and amino acid sequence to the sulfur-rich gliadins and were recently classified as aggregated gliadins (Kreis et al. 1985).
Cereal starch granule development and composition
Authors: r. Morrison William
Published: November 2023

According to the classical texts (Banks and Greenwood 1975; Whistler et al. 1984; Kainuma 1988) cereal starches are composed of two types of polysaccharide, amylopectin and amylose, and little attention is given to the minor components of the granules such as the integral proteins and lipids. The integral proteins consist of a major polypeptide (58–60 kDa) identified as granule-bound starch synthase, with traces of polypeptides of higher molecular weight (Echt and Schwarz 1981; Sano 1984; Goldner and Boyer 1989). The major integral protein (the so-called waxy protein) is generally determined by a single gene (Wx), and in the waxy mutants of the diploid cereals where the gene (wx) is not expressed there is no detectable waxy protein and typically less than 2 per cent amylose (Villareal and Juliano 1986; Goldner and Boyer I 989). In the triploid endosperm intermediate states between normal (Wx Wx Wx) and waxy (wx wx wx) are possible, and both Wx Wx wx and Wx wx wx genotypes have slightly less waxy protein and amylose than in the normal starches (Nelson 1980).
SNF1-related protein kinase genes in cereals
Authors: Halford Nigel G
Published: November 2023

Considerable advances have been made in the study of the regulation of plant gene expression in response to stimuli such as light, temperature, the action of pathogens, and developmental signals. However, relatively little is known about the effects of metabolite levels on the activation of genes encoding enzymes, including those involved in the pathways leading to the accumulation of storage products. Evidence is beginning to emerge that complicated signal transduction pathways exist to enable the plant cell to respond to its metabolic status by activating or inactivating gene expression. One such piece of evidence is the isolation in this laboratory of plant homologues of the yeast gene SNF1 (sucrose nonfermenting 1) (Celenza and Carlson 1986), a gene which encodes a protein serine/threonine kinase which has been described as a global regulator of carbon metabolism in yeast. The role of such systems in the regulation of important metabolic processes and their potential effects on the partitioning of carbon within the harvested organs of crop plants make them prime targets for genetic manipulation as well as of fundamental scientific interest.
Pathways to starch and fatty acids in plastids isolated from developing embryos of oilseed rape
Authors: Fan Kang , Rawsthorne Stephen
Published: November 2023

Oilseed embryos import carbon as sucrose, and this is then partitioned between the storage products which are laid down in the developing tissues. In seeds of oilseed rape the main storage products are oil and protein, although starch accumulates transiently during the early phase of oil deposition (P. da Silva and A.M. Smith, unpublished). Fatty acids and starch are synthesized in the plastid, and several cytosolic metabolites could traverse the plastid membrane and enter these biosynthetic pathways (Dennis et al. 1991). Metabolic regulation in the cytosol could determine the availability of these metabolites, and once inside the plastid further regulation could determine which biosynthetic pathways they then enter. We therefore need to understand the metabolic pathways involved in the partitioning of carbon so that potential points of regulation can be identified.
Synthesis and accumulation of human tissue-type plasminogen activator (h-tPA) in transgenic tobacco seeds
Authors: Becker Claudia , Hainong Van , BÄumlein Helmut , Le Thixuan , Farouk Abdel-Azim , Will Horst , Bassuner Ronald
Published: November 2023

One of the aims of plant genetic engineering is to employ the plant as a potential host organism for the production of commercially valuable substances. Only few therapeutically valuable proteins have been shown to be expressed in transgenic plant tissues: human interferon (De Zoeten et al. 1989), Leu-enkephalin (Vandekerckhove et al. 1989), mammalian immunoglobulin (Hiatt et al. 1989; During et al. 1990), and human serum albumin (Sijmons et al. 1990).
Opportunities for genetic engineering of oil production
Authors: Safford R
Published: November 2023

Plant oils are of major economic importance, being utilized in a number of food and industrial applications. The fatty acid composition of an oil determines its physical and chemical properties and hence its uses and its value. Because in many cases the fatty acid composition of an oil is less than optimal, there is considerable interest in exploring genetic approaches to upgrading the oil composition of seeds. Hitherto a number of improved oils have been produced either by conventional plant breeding or by mutagenesis and selection approaches. One of the earliest successes from breeding programmes was the production of low-erucic acid rapeseed oil (Stefansson et al. 1961) which was suitable for edible purposes. Mutagenesis programmes have produced, amongst others, high-oleate safflower (Ladd and Knowles 1971) and sunflower (Fick 1989) oils which have superior qualities as cooking oils, high-stearate soybean oil for margarine production, and low-linoleate linseed oil (Green 1986) which can be used for edible purposes. These studies have demonstrated the plasticity of seed oil composition in that significantly large alterations in seed oil fatty acid composition can be made without any detrimental effect on oil yield or growth and development of the plant. Conventional plant breeding and mutation and selection methods are empirical in nature, are limited by the genotype of the species, and are restricted to deletion of gene function. The recent development of facile techniques for the introduction of cloned genes into plants now opens up the possibility of producing improved oils by overexpressing endogenous genes, by the transfer of novel genes from any organism, or by the selective inactivation, via anti-sense technology, of gene function.
Enzyme modification of seed storage compounds for industrial use
Authors: Cowan W D
Published: November 2023

Seed storage compounds provide one of the largest sources of raw materials for the enzyme industry to process. Of a worldwide turnover of some £109 per year, the second largest sector, that of starch processing accounts for around 25 percent of the total enzyme demand. When other industries such as brewing, textiles,and baking are added to this, the total amount is over 30 per cent (Fig. 25.1).
A Possible Method for the Rapid Assessment of Biodiversity
Authors: Oliver L , Beattie A J
Published: November 2023

A method is described for rapid assessment of biodiversity using a wider variety of taxa than the usual inventories of flowering plants and vertebrates. To explore the value of invertebrates and cryptogamic plants as surrogates of biodiversity, estimates of species richness of spiders, ants, polychaetes, and mosses were undertaken by classifying them as Recognisable Taxonomic Units (RTUs), and comparing them with specialist identifications. RTU estimates turned out to be close to formal taxonomic estimates for the invertebrates but were misleading for mosses. It was concluded that trials of all groups deemed to be useful for RTU analysis needed to be evaluated before reliability could be attained. Taxonomic specialists are considered indispensable to train personnel, to undertake the preliminary trials, and to check the results of RTU estimates before wholesale studies were undertaken by ‘biodiversity technicians’.
Global Patterns of Endemism and the Conservation of Biodiversity
Authors: Thirgood S J , Heath M F
Published: November 2023

The approach to conservation of biodiversity by the International Council for Bird Preservation Biodiversity Project is described. The assumption is made that centres of endemism are priorities for the conservation of biodiversity. Birds were selected as a high priority target group, since most species are known and described, and are present throughout all major ecosystems of the world. Distributions of all species with breeding ranges restricted to 50 000 km2, or less, were chosen as the study group. The analysis revealed that 2 497 species (26 per cent of all birds) were shown to occur in 221 endemic bird areas (EBAs) which cover about 5 per cent of the world’s land area. Two questions were asked of the results: (I) Is there congruence of patterns of endemism between different animal and plant groups? (2) Are endemic birds good indicators for areas of endemism in other plant and animal groups? Through a regional assessment of the 221 EBAs it is shown that there is good congruence between global patterns of endemism in birds and other taxa, although exceptions were noted for the several groups of organisms in the UK and plants in the neotropics. It is argued that the 221 EBAs should be conserved as a first priority, and that the International Council for Bird Preservation Biodiversity Project is justifiable since collection of more sophisticated data will take longer than conservation can wait.
Species as the ‘Currency’ of Conservation: the Karoo/Dune/Red Lark Complex of South-Western Africa
Authors: Crowe T M , Ryan P G , Brooke R K , Hockey P A R , Siegfried W R
Published: November 2023

Species are considered to be the fundamental units of conservation. This brief account describes a multifaceted approach using morphological, behavioural, ecological, and genetic information to illustrate an appropriate strategy for recognizing species. The Karoo/Dune/Red Lark species complex in south¬ western Africa is examined as an example of this approach since at least 21 authors have expressed opinions about their natural status. By analysis of qualitative variation in plumage, mensural, behavioural, and genetic characters, together with habitat details, two genera and four species of these larks are recognized as the basic units of conservation.
Mitosis and cell division
Authors: Hori T , Green J C
Published: November 2023

The fine structural changes during mitosis in members of the Prymnesiophyceae are reviewed with special reference to the behaviour of the periplastidial endoplasmic reticulum (PER) and the structures associated with the spindle poles. As in other chromophyte algae, the nuclear envelope (NE) and PER are confluent in interphase cells of members of the Prymnesiophyceae. In some species, PER-NE confluence is maintained during chloroplast replication, whilst in other species the PER-NE link breaks down. Disruption of the PER-NE link usually occurs at prophase, PER-NE confluence being restored at metaphase or in the later stages of mitosis. Some organelles, especially mitochondria, may play an important role in determining the positioning of the spindle poles and in extension of the anaphase spindle, since long mitochondrial profiles are well developed around each spindle pole and along the interzonal spindle at anaphase. Hitherto, structured microtubule organizing centres (MTOCs) have not been observed in the Prymnesiophyceae other than in Pavlova, but we report here the presence of MTOCs composed of osmiophilic amorphous material on the surface of mitochondria in cells of Phaeocystis globosa.
The Centromere
Authors: Choo K H Andy
Published: November 2023

The centromere is an essential structure on all eukaryotic chromosomes that allows the equipartition of chromosomes during mitotic and meiotic cell divisions. Since its cytogenetic recognition as a constructed part of a chromosome many decades ago, great advance has been made on our understanding of this intriguing structure, especially at the molecular level. This book brings together all available information on the centromere. It covers in details the DNA and protein components of this structure, and their individual functions, in species as diverse as budding and fission yeasts, nematodes, Drosophila, mice, and humans; newly discovered roles of the centromere in marshalling "passenger" proteins; important emerging concepts such as latest centromeres and epigenetic factors; cytogenetic problems associated with centromere abnormalities; and practical application of centromere studies, such as in the construction of human artificial chromosomes for gene therapy. Supported by ample illustration, the book is written with sufficient simplicity and detail to suit both specialist and non-specialist scholars. It is the first book on the subject
Introduction
Authors: Choo K H Andy
Published: November 2023

Fundamental to all the life processes is the ability of the cells to divide faithfully. This division can take the form of the equipartitioning of the genetic materials of a mother cell between two daughter cells (mitosis), or the accurate reduction of chromosome number (meiosis). That ‘the cell has no other mode of origin than by division of a pre-existing cell’, a realization made by Wilson (1925) and his contemporaries decades ago, clearly ex pounds the pivotal role played by these two divisional processes. In exercising this extraordinary ability to divide, the cells are equipped with innumerable mechanisms to achieve the high degree of accuracy that is needed. That this is so is evident from the observed low error rates of approximately 10-5 per generation for mitotic chromosome segregation and 10-3 per generation for meiotic chromosome segregation (Hawley 1988; Brown et al. 1991). How the cells accomplish these unusual and understandably complex feat is presently far from being fully understood. It is against this backdrop of realized importance and expected complexity that many keen biologists have risen to the challenge. In this pursuit, the centromere, a highly specialized structure of the chromosome, has long been recognized as having a centre stage role in the processes of cell division. Through many years of dedicated investigation, much has now been learnt about the centromere, and it is the purpose of this book to review all the recent advances in our understanding of this complex and highly intriging structure.
Structural organization and general properties of the higher eukaryotic centromere
Authors: Choo K H Andy
Published: November 2023

Standard cytogenetic staining of the chromosomes of higher eukaryotes reveals the centromere as a constricted and relatively homogeneous region of densely packed heterochromatin, but gives little clue to the underlying complexity of this structure. With improved techniques of cell fixation for electron microscopic analysis and the use of specific antibodies that allow sub regional staining of the centromere, it is now clear that the centromere of higher eukaryotes is structurally composed of a number of distinct domains. Within these domains are located the basic centromeric DNA molecule and an increasing number of known protein components that participate in the activities of the centromere. In this chapter, the structural organization as well as a number of general properties of the higher eukaryotic centromere are described. Where appropriate, the names of relevant DNA and protein components found in the different centromeric domains are mentioned, but detailed discussion of these components will be presented in Chapters 5 and 6.
Centromere DNA of higher eukaryotes
Authors: Kalitsis Paul , Choo K H Andy
Published: November 2023

Perhaps the most striking known structural characteristic of the centromeres of the higher eukaryotes is the universal presence of a great abundance of tandemly repeated DNA. The amount of this DNA can range from hundreds of kilobases to tens of megabases on each centromere. This property suggests a priorithat the centromere of the higher eukaryotes may be a molecularly complex structure that is difficult to study. However, despite this suggestion, many workers have been attracted to its study due to its perceived biological as well as potential practical importance (Chapter 8). On the other hand, the centromeric repeats, by their very abundant nature, can be relatively easily isolated for study. Many such repeats have now been identified and cloned from different organisms. Through the structural analysis of these repeats, it has become apparent that there is a widespread lack of sequence conservation of centromeric DNA throughout the phylogeny. Furthermore, although a substantial amount of structural information is now available for these centromeric repeats, the delineation of the functional role of these highly divergent sequences yet presents a challenge of a somewhat different magnitude. In this chapter, the current state of our knowledge on the molecular properties of the centromeres of a selected number of higher eukaryotes is described.
Anomalies of the human centromere
Authors: Choo K H Andy
Published: November 2023

Clinical abnormalities that can be directly attributed to defects of the centromere are rarely seen. This is understandable considering the important roles the centromere plays in mitosis and meiosis. Nonetheless, based on various cytogenetic and molecular criteria, some interesting anomalies of the human centromere have been described.
Practical applications
Authors: Choo K H Andy
Published: November 2023

Apart from its intrinsic biological importance and interest, the study of the centromere offers a number of immediate and potential practical applications. Two specific applications, namely the detection of chromosomal abnormalities and the construction of mammalian artificial chromosomes, are discussed below.
St Andrews: the Scottish experience
Authors: Williams Trevor I
Published: November 2023

While the plight of the Robinsons in Huddersfield was not such that they were obliged to find any port in a storm, so quickly to find an agreeable haven in the small university town of St Andrews was a stroke of good fortune. Moreover, it had been attained with minimal trouble, for he had been appointed without any personal interview, and after merely the perusal of applications. The milieu was very different from any they had previously experienced in Sydney or in the thriving industrial cities of Manchester and Liverpool. In the 1920s the population of St Andrews, perched on the cliffs of Fife some fifty miles by road from Edinburgh, was less than 10 000: even today it is only 12000. The university, founded in 1410, is the oldest in Scotland: the other ancient foundations arc Glasgow (1451), Aberdeen (1495), and Edinburgh (1583). In 1881 the University College of Dundee was founded some dozen miles away, and in 1897 this had been affiliated to the University of St Andrews: technically, Robinson held office in both.
Pre-war Oxford
Authors: Williams Trevor I
Published: November 2023

Oxford was already familiar to Robinson, for over the years he had been a frequent visitor there. He had maintained close links with W. H Perkin in the context of research, he had supervised research students, he had been an external examiner, he had attended lectures and conferences, and so on. Nevertheless, the peculiar constitution of the University, and its devotion to tradition, was to present him with professorial problems of a kind he had not previously encountered. As these peculiarities will be at least as unfamiliar to many readers as they were to Robinson, it is useful to digress briefly to review the Oxford scene in general, and the chemical scene in particular, in the early 1930s. This is very relevant, in that Robinson’s activities were much influenced by the constraints within which he had to work.
The Second World War
Authors: Williams Trevor I
Published: November 2023

By 1938 the inevitability of war with Germany had become generally recognized. Chamberlain’s policy of appeasement, and his much quoted ‘Peace in our time’ message after meeting Hitler at Berchtesgaden and Godesberg in September carried little conviction in the face of continuing aggressive German policy. This included the earlier occupation of Austria in March, the occupation of the Sudetenland in October, and the invasion of Czechoslovakia in March 1939. In that same fatal month Hitler denounced Germany’s non-aggression pact concluded with Poland in 1934; and within days France and Britain pledged themselves to support Poland. In August Germany signed a non-aggression pact with Russia; and on the 25th of that month a formal Anglo-Polish treaty of mutual assistance was signed in London. The mine had been primed, and it needed only the German invasion of Poland on 1 September to explode it Britain and France declared war on Germany on 3 September, precipitating a Second World War barely twenty years after the end of the first.
The darkening years
Authors: Williams Trevor I
Published: November 2023

Sadly, Robinson’s later years were clouded by failing sight, and all the constraints this imposes even when other faculties are largely unimpaired. In his case the affliction took the form of tunnel vision, in which the victim sees the world as it were through a tube of slowly diminishing bore. Its onset and development are insidious: it is not clear when the symptoms first appeared, but a letter to Victor of 21 May 1970 shows signs of real trouble. Its main purpose was to apologize for having forgotten Victor’s birthday on the 19th, ‘but tempus fugit at an alarming rate these days’. The writing is firm, but his sight is clearly troubling him: there is a very wide margin on the left-hand side, and some of the writing trails off over the edge of the page, so that a few words are incomplete or lost altogether.
The deserts of Egypt: desert development systems
Authors: Bishay A
Published: November 2023

Egypt suffers from continued population growth and dwindling resources. With Egypt’s population (57 million in 1992) concentrated in the Nile Valley, which constitutes less than 4 per cent of the total area of the country, development of her deserts to make them productive and habitable is an urgent need that is widely recognized. In order to solve the problems of food and housing for the continuously increasing population, the Egyptian Government has decided to expand horizontally (in the desert) as well as continuing the present successful vertical improvement of its cultivable land. According to the Government of Egypt, a minimum of 150 000 feddans per year will be reclaimed during the current Five Year Plan. Estimates for long-range desert reclamation plans range between 1.6 and 3.4 million feddans, with the figure of 2.3 million feddans adopted officially by the Government of Egypt.
Natural vegetation
Authors: Wickens G E
Published: November 2023

The first major attempt to produce a description and map of the vegetation of the Sudan was in 1948 by the Sudan Government’s Senior Economic Botanist, Dr F. W. Andrews, in a publication that had similar coverage and objectives to the present volume (Andrews 1948). The same classification with slight modifications was followed by Dr John Smith, the then Director of Agriculture and Forests, and a former Chief Conservator of Forests (Smith 1949). A decade later, M. N. Harrison, Pasture Research Officer in the Ministry of Animal Production and J. K. Jackson, Silviculturist in the Forests Department, each working independently, produced somewhat similar classifications of the vegetation, the former placing greater emphasis on grazing, the latter on tree resources.
Land tenure
Authors: Simpson I G
Published: November 2023

The Sudan has a large land area but remains relatively thinly populated. Nevertheless, the continuing rapid population growth and the development of large-scale mechanized agriculture are resulting in perceived shortages of land in various parts of the country, especially in the central belt. There has always been a strong demand for irrigated land, use of which gives freedom from the constraints of an uncertain and often limited rainfall confined to only a few months of the year. Once the demand for agriculturally-usable land exceeds the available supply, systems of landholding and tenure become increasingly important determinants of production. In recent years land tenure systems have become major issues of agricultural policy, especially in relation to the large-scale irrigation schemes and rainfed mechanized farming.
Food preferences and nutrition of the people
Authors: Ali M Z
Published: November 2023

Sudan, with about 200 million feddans of fertile arable land and 55 million heads of camels, cattle, goats, and sheep, is, potentially, a prosperous country in terms of national supplies of food raw materials. The varying climatological zones, ranging from the humid tropics to the barren desert, also provide different niches for the production of various kinds of animals, crops, and foods.
Historical development of agriculture
Authors: Trilsbach A
Published: November 2023

The present agricultural landscape is the product of a long evolution. The contributing forces include environmental changes of the past 5000 years; the ebbing and flowing of empires from the early days of Ancient Egypt to the Anglo-Egyptian Condominium of the present century; advancing technologies from the earliest introduction of the shaduf to the sophistication of the Kenana sugar complex; and the position of Sudan in a world of international trade.
The symmetric immune network model
Authors: Rowe Glenn
Published: November 2023

One of the first models based on Jerne’ s network theory was proposed by Hoffmann in 1975, with several modifications and extensions since then. The model avoids the problems of the huge number of variables in a full immune network by grouping all the cells and antibodies into two classes: plus cells (and related antibodies) and minus cells and antibodies.
The Germ Of An Idea
Authors: Lax Alistair J
Published: November 2023

Diseases caused by toxins were among the earliest described. Reference to what we now know as cholera is outlined in early Chinese medicine. However, the first detailed accounts of disease that are available today are those of the Greeks, at the time that medicine really began. Diphtheria was described over 2,000 years ago, and the poet Virgil wrote an account of anthrax.
The Anatomy Of Diphtheria
Authors: Lax Alistair J
Published: November 2023

Diphtheria occupies a particularly special place in microbiology and its history. It has probably been studied in more depth than any other disease. We know exactly how it causes damage to our bodies, which surprisingly is still not known for most diseases. Diphtheria toxin was the first complex toxin to be understood at the molecular level, and it continues to produce interesting results. It represents the ultimate model toxin and illustrates beautifully how such toxins work. Its malevolent action was one of the first to be tamed by vaccines so effective that the basic formula has not changed substantially in over 80 years. In addition, its potent action has now even been turned to cancer therapy.
A More Optimistic Outcome
Authors: Lax Alistair J
Published: November 2023

For the pessimist, the last three chapters have painted an increasingly gloomy picture of potent and deadly molecules that possess within their molecular architecture an inert but uncanny knowledge of the workings of our bodies. These can either cause fatal disease naturally, or can be used by the madmen of the world as vicious and terrifying weapons. The optimist would have seen some hope as the nineteenth- and twentieth-century scientists gained an understanding of these molecules, and would be cheered by the observation that the use of bioweapons is being curtailed by most countries. However, there are highly positive aspects to these molecules.
Distant Shores
Authors: Wilkins Maurice
Published: November 2023

I am glad to have been brought up in the constructive spirit and breadth of vision that has its roots in the seventeenth-century English Revolution, when freedom of thought replaced Authoritarianism. My earliest known ancestor, Philip Henry, a minister, joined the move away from Authoritarianism and became, like his contemporary Isaac Newton, a Nonconformist and a Unitarian, seeing one God, not three. In the English Church tried to turn the clock back by reinstating authority in its Statute of Conformity, and Henry was one of many to give up his ministry in protest. Unitarians set up their own Chapels and schools, and took a leading part in the growth of science and the Industrial Revolution.
Go Back to your Microscopes
Authors: Wilkins Maurice
Published: November 2023

The prospects of our DNA X-ray work brightened as summer began. At Naples I had been encouraged by Astbury’s warm response to our crystalline DNA pattern, and by my success in making X-ray specimens with sperm heads all lined up. Back in London, it was good that Rosalind had begun reconstructing our new X-ray equipment. While waiting for that, I made do with the old set-up we had used a year before for our breakthrough in understanding the crystallinity of DNA. I began thinking about the basic biological importance of the DNA pattern, and wondered if the structure of Signer DNA (which was made from calf thymus glands, sold as sweetbreads by butchers) was basic- ally the same as that of DNA in other living things. Was there just one universal gene structure? If so, our sharp Signer pattern could have a very wide (and big) significance. Mary Nicholls in our lab had extracted DNA from humans and herrings as well as calves, and I decided to compare the diffraction from her DNA with that from the DNA from the Sepia sperm that I had brought back from Naples.
The Double Helix
Authors: Wilkins Maurice
Published: November 2023

When I got back to London, I was glad to find that Herbert Wilson had arrived to work with me. He had a PhD on X-ray studies. I asked him to develop further what we had done on sperm heads and to try other nucleoproteins – naturally occurring complexes of protein and DNA from which DNA can be extracted. Since Herbert would not be working on purified DNA, he could not be seen as encroaching on Rosalind’s area. In any case, I had given Rosalind all our good DNA. Also, I had a special interest in studying DNA in its natural state (such as is found in sperm), because it seemed reasonable to me to think that its structure might give us new ideas about how it functioned as gene material.
Background to the Comparative Method
Authors: Fox Anthony
Published: November 2023

The Comparative Method is both the earliest and the most important of the methods of reconstruction. Most of the major insights into the prehistory of languages have been gained by the application of this method, and most reconstructions have been based on it. The various other methods and procedures outlined in the previous chapter, which will be considered in more detail later, have been employed mainly in a secondary capacity, in part building on the findings of the Comparative Method, and in part supplementing them, but only rarely competing with the method as such. Not surprisingly, there fore, this method has often been regarded as virtually identical with the historical study of languages, as witnessed by terms such as 'comparative linguistics', 'comparative philology', and so on, which have been used to designate the whole field. The method has therefore come to epitomize the subject, especially as practised in the nineteenth century.
The Comparative Method in the Twentieth Century
Authors: Fox Anthony
Published: November 2023

The most significant contribution to the study of language in the twentieth century has been not in the field of historical linguistics at all, but in the development of synchronic linguistics, which, as we have noted above, provides a different, and complementary, dimension to the diachronic approach which characterized the nineteenth century. There is a sense, of course, in which this dimension is not simply complementary to the historical study of language but is actually in conflict with it, since it is not necessarily obvious how we can reconcile the two: the nineteenth-century view of language was as a historically determined object, which can only be comprehended and explained in terms of its history; twentieth-century synchronic linguistics has preferred to see language as a coherent systematic whole, whose history is largely irrelevant to its function and structure. Saussure himself, who can be said to have clarified this distinction and drawn the appropriate conclusions from it, was in fact unable to reconcile these two dimensions adequately. Nevertheless, it is precisely in the priority given by twentieth-century linguistics to the synchronic dimension, and the consequent reappraisal of the diachronic dimension, that its most distinctive, and most positive, contribution to historical linguistics lies.
Issues in Comparative Reconstruction
Authors: Fox Anthony
Published: November 2023

As we have noted, the Comparative Method has been employed, and continues to be employed, in reconstructing the earlier stages of languages and language families in all parts of the world. The fact that it still enjoys the confidence of the majority of historical linguists suggests that it is considered to produce useful and reliable results. There are, however, a number of fundamental questions that need to be discussed which relate to the nature of the assumptions on which the method is based, and the extent to which these assumptions can be reconciled with what we know, or believe, about the processes of language change. We have already discussed (in Ch. 1) the status of reconstructed forms themselves, and considered differing views about their validity, but serious doubts have also been raised about the status of the methods used to establish these forms, which seem to demand an interpretation of the nature of language change which is at variance with currently acceptable theories. This chapter will therefore examine briefly the main issues involved here.
Applications and Implications of Internal Reconstruction
Authors: Fox Anthony
Published: November 2023

Like the Comparative Method, Internal Reconstruction is most commonly, and most effectively, applied in phonology, reconstructing pre-phonemes on the basis of sets of alternating phonemes. How ever, alternation of this kind, though characteristically phonological, is found elsewhere, and it should be possible to generalize these principles, so that any alternation-whether phonological, morphological, syntactic, or semantic-can be used to reconstruct an abstract non-alternating source, which can then be ascribed to the pre-language in question.
Reconstructing Language Relationships
Authors: Fox Anthony
Published: November 2023

Apart from the reconstruction of the forms and systems of protolanguages, a further task of comparative reconstruction is to determine the historical relationships between languages themselves. The reconstruction of proto-languages on the basis of the Comparative Method does, of course, presuppose that the languages compared are related, and indeed, successful reconstruction provides a demonstration of such relationship, but it is not concerned with the nature and degree of the relationship; it assumes that the languages belong to the same family but does not require us to know the nature of the internal relationships within the family.
Reconstruction, Culture, and Society
Authors: Fox Anthony
Published: November 2023

In previous chapters we have considered the principles of linguistic reconstruction in so far as they affect the language itself, seen as a complex of systems, rules, structures, and so on. But a language does not, of course, exist independently of its speakers and of the speech community in which they live, and there is a further role for reconstruction in relation to this social and cultural dimension. In the early stages of the historical study of language, in the late eighteenth and early nineteenth centuries, language and culture were not, in fact, considered separately; the work of the Schlegel brothers on Sanskrit and the Grimm brothers on German, for example, was not confined to the languages concerned but embraced the whole culture of the people, where the language was merely an expression of the 'spirit' of that people.1 We saw that, by the second half of the nineteenth century, linguists had come to pride themselves on the scientific status of their discipline, with the development of the Comparative Method, but this development was achieved by emancipating the study of language from the study of culture.
Semantic Complexity and the Role of Ostension in the Acquisition of Concepts
Authors: Wierzbicka Anna
Published: November 2023

In modern semantics, progress seems to have been impeded, more than anything else, by unrealistic expectations. Familiar analyses of meaning along the lines of to killequals ‘to cause to die’ or bachelorequals ‘unmarried man’ have seldom been regarded as satisfactory, but they have helped to perpetuate the illusion that if the meaning of a word cannot be stated sat-isfactorily in a simple formula of three or four words, then what is needed is a longer and more complex one, of five or six words.
Against “Against Definitions”
Authors: Wierzbicka Anna
Published: November 2023

In this chapter I will not try to review the enormous literature on definitions but rather present my own conclusions on the subject emerging from work on hundreds of definitions, pursued over nearly three decades.
The Semantics of Natural Kinds
Authors: Wierzbicka Anna
Published: November 2023

How is knowledge stored and organized in the human mind? In particular, does the mind draw a distinction between “linguistic knowledge” and “nonlinguistic knowledge”, or between a “mental dictionary” and a “mental encyclopaedia”? For example, what do ordinary people know and how do they think about mice, crocodiles, or moths? Can the knowledge encapsulated in the everyday meaning of words such as mouse, crocodile,or mothbe separated from the knowledge that people may have aboutmice, crocodiles, and moths?
Semantic Rules in Grammar
Authors: Wierzbicka Anna
Published: November 2023

As I have tried to show (see in particular Chapter 5), a word’s syntactic behaviour reflects, and depends on, its meaning. Thus, it is no accident that one can ask, beg,or applyFOR something, but not order, demand,or commandFOR something; or that one can both orderand asksomeone TO DO something, but not demandor applysomeone TO DO something.
A Semantic Basis for Grammatical Description and Typology: Transitivity and Reflexives
Authors: Wierzbicka Anna
Published: November 2023

Grammar encodes meaning. Categories of grammar known, traditionally, as “plural”, “dual”, “past”, or “imperative” encode semantic distinctions which in a given speech community are deemed (at a subconscious level) particularly important. The difference between a swallow and a lark can (at times) be ignored by the speakers of English because they can both be subsumed under a more general label “bird”; but the difference between a birdand two or three birdscannot be similarly ignored: for the speakers of English, the distinction between singular and plural is obligatory (for “count nouns”).