bluuebunny/crossref_metadata_2025 huggingface dataset:
Sir William Jones
Authors: Desmond Ray
Published: November 2023

In the summer of 1793 William Roxburgh was summoned to Calcutta to be considered for the post of the first salaried Superintendent of its botanical garden. The English flag had been hoisted over a small settlement on the banks of the River Hooghly in Bengal in 1690 and within a century Calcutta’s population had swollen to half a million. Its trade had outstripped the ports of the Coromandel coast and when Surat, once the dominant commercial centre of all India, was weakened by internal wars, its position became unassailable. The East India Company created a Georgian city on a former malarial swamp. The Victorians, admiring its broad roads fronting large mansions with classical facades, stuccoed and whitewashed, and set in smooth lawns with shrubberies and shadegiving trees, called it the City of Palaces. But it was also a city of contrasts: European elegance was surrounded by open drains, mud huts, and the stench and filth of narrow streets in crowded bazaars. Parliament’s Regulating Act of 1773 elevated the Governor of Bengal, Warren Hastings, to Governor-General with authority over the Presidencies of Madras and Bombay. Calcutta became the seat of the Government of British India and the location of the new Supreme Court of Judicature. It boasted theatres, an orchestra and choir that performed Handel’s Messiah to home-sick Britons, a race-course, and a learned society presided over by (Sir) William Jones (1746-94).
Pursuit Of The Picturesque
Authors: Desmond Ray
Published: November 2023

Until Hodges’s paintings were published in London towards the end of the eighteenth century, the British visual perception of India relied upon engravings inspired by travellers’ descriptions or amateurs’ drawings. William Hodges (1744-97) was the first professional artist of any merit to record his impressions of the subcontinent. Trained at William Shipley’s drawing school in the premises of the Society of Arts, he was apprenticed to the landscape painter Richard Wilson, a devotee of the classical landscapes of Claude and Poussin. Hodges learnt from Wilson how to compose poetic landscapes in the manner of these French painters, adroitly manipulating atmospheric light and shade on canvas and paper. The Admiralty engaged him as a topographical artist on Captain Cook’s second voyage to the Pacific in 1772. During his three years on HMS Resolution, he had to subordinate his romantic vision to the prosaic requirements of topographical accuracy. He returned to the tropics, selecting India as a subject for his brush after the death of his wife in 1777. Landing in 1780 on the broad strand skirting Madras, his trained eye appraised approvingly ‘the clear, blue, cloudless sky, the polished white buildings, the bright sandy beach, and the dark green sea’. Such light and strong colours tested his technical skills, the country and its inhabitants proffered picturesque compositions-temples and forts, parades of soldiers, caravans of merchants, and the ‘fine antique figures’ of women emerging from the river ‘with wet drapery which perfectly displays the whole person’. He was attracted by the extraordinary configuration of the banyan tree. He rejoiced in the rebirth of the countryside during the monsoons, everywhere ‘such a freshness of verdure ... such vigour and fulness of foliage’. The powerful aquatints in his Select views of India (1785-8) enticed other artists to the country.
Gardening In India
Authors: Desmond Ray
Published: November 2023

The hymns that constitute the Rig Veda required flowers to be used in religious ceremonies and through these ancient Hindu texts we discover that gardens have enjoyed a long tradition in India. Garland-makers grew flowers for festivals and most households tried to cultivate a few blooms to offer in prayer and ritual. Trees with sacred associat10ns such as Kadam (Neolamarckia cadamba) and Champaka (Michelia champaca) are still familiar sentinels in temple gardens. Public parks were laid out for recreation, usually on the outskirts of towns and frequently near rivers. Asoka, the greatest emperor of the Mauryan empire and a Buddhist convert, encouraged the planting of trees along highways as well as in parks and gardens. His pillar in Delhi, one of a number erected throughout the empire proclaiming royal edicts, announced ‘that everywhere wholesome vegetables, roots and fruit trees shall be cultivated, and that on the roads wells shall be dug and trees planted to give enjoyment for both men and animals’.
Differential binding and activation of synthetic retinoids to retinoic acid receptors
Authors: Apfel Christian , Crettaz Marco , LeMotte Peter
Published: November 2023

Retinoids, and in particular all-trans retinoic acid (RA), exert a wide range of biological effects. RA influences the growth and differentiation of a wide variety of normal and transformed cells. The usefulness of retinoids in dermatology in different skin disorders, such as acne and psoriasis, is well documented. Moreover, retinoids may have a potential in immunomodulation and as preventive and therapeutic anticancer agents (Bollag 1979; Bollag 1983; Lippman et al., 1987). The mechanism by which RA induces these diverse biological effects is unclear. Initially, it was suggested that they were mediated through a highly specific cellular RA-binding protein (Jetten and Jetten 1979). A crucial advance towards understanding retinoid action has been accomplished with the isolation of six specific nuclear receptors for retinoids RAR-α (Petkovich et al. 1987; Giguere et al. 1987), RAR-β (Benbrook et al. 1988; Brand et al. 1988), RAR-γ (Kastner et al. 1989; Krust et al. 1989; Giguere et al. 1990), RXR-α, RXR-β, and RXR-γ (Mangelsdorf et al. 1990 and Chapter 3). These receptors belong to the superfamily of steroid/thyroid hormone receptors. This family of nuclear receptors regulate gene transcription in a ligand-dependent fashion through binding to specific DNA sequences (response elements), generally located upstream of the promoter of a target gene (Umesono et al. 1988; Graupner et al. 1989; Vasios et al. 1989; de Thé et al. 1990). This results in an increased or decreased synthesis of specific proteins.
Retinoid-induced alterations of segmental organization and gene expression in the mouse hindbrain
Authors: Murphy Paula , Davidson Duncan R , Hill Robert E , Morriss-Kay Gillian M
Published: November 2023

The organization of the vertebrate body plan during development is not well understood. In invertebrates, such as Drosophila, the embryo is divided into repeated units along the anteroposterior (AP) axis; which subsequently develop into distinctive parts of the adult (for review sec Akam 1987). The process of segmentation, in which initially similar units diversify according to position, simplifies the task of constructing a complex organism. Drosophila segmentation has been well characterized at the genetic level and more than 50 genes that establish or distinguish segments have been identified (Lewis 1978; Nusslein-Volhard and Wieschaus 1980; Perrimon et al. 1982; Jurgens et al. 1984; N usslein-Volhard et al. 1984; Wicschaus et al. 1984; Schupbach and Wieschaus 1986; Akam 1987). Many of these are DNA regulators that belong to conserved families of genes that are represented in vertebrates (for reviews sec Holland and Hogan 1988; Kessell and Gruss 1990). However, not surprisingly, vertebrate embryos arc more complex than Drosophila and are not entirely segmental in form. One part of the vertebrate embryo that is clearly segmented is the hindbrain, where repetitive morphological structures (rhombomeres) have been shown to reflect an underlying segmental organization to neurogencsis (Adelman 1925; Lumsden and Keynes 1989). In mouse embryos, individual hindbrain segments show specific patterns of gene expression. Two of these segment-specific genes show an alteration in their pattern of expression when retinoic acid (RA) levels are raised. They are: Krox-20, which contains zinc finger DNA binding motifs and is expressed in rhombomercs 3 and 5 (Wilkinson et al. 1989a), and Hox-2. 9, which is expressed in the intervening rhombomere, rhombomere 4, and contains a homeobox similar to those found in Drosophila homeotic genes which confer segment identity (Murphy et al. 1989; Wilkinson et al. 1989b). Among Drosophila genes, Hox-2 .9 is most closely related to labial, which identifies an ancestral segment in the Drosophila head (Frohman et al. 1990; Murphy and Hill 1991).
Analyses of drugs and drug concentrations in blood and other body compartments
Authors: Ferner R E , Norman Elizabeth , Rawlins M D
Published: November 2023

The forensic pharmacologist is constrained to provide his opinion on the basis of the information he has about a case. The more information, the more he can usefully say. At one extreme, he may be asked whether any drug could possibly have caused a series of events. At the other extreme, there will be several measurements of drug concentration to help in estimating times, doses, and possible effects. Tests to detect drugs, and to measure their concentrations, are extremely important. Their limitations are also important. The methods and their pitfalls are discussed here.
Legal considerations
Authors: Ferner R E , Norman Elizabeth , Rawlins M D
Published: November 2023

The function of the expert witness within the English legal system is the same whatever the area of expertise. The problem faced by the would-be expert in identifying the nature of that function may vary, depending on the nature of that expertise. The doctor, for example, is accustomed to diagnosing and treating illness, but may be less comfortable in saying what percentage of a patient’s disability is attributable to a particular injury, the very issues that the legal system may want addressed. It is very important to understand the basics of how the legal system works, in order to see what it actually requires of the expert. In that way, a lot of time (on behalf of the doctor) and frustration (on the part of the lawyer) can be saved. It is also important to understand how lawyers function in court.
Detection of genetic changes in cancer by interphase cytogenetics and comparative genomic hybridization
Authors: Hopman Anton H N , Voorter Christina E M , Speel Ernst J M , Ramaekers Frans C S , Vooijs Peter G
Published: November 2023

Quantitative and structural aberrations in the genomic content of malignancies or premalignant lesions, are, in many cases, correlated with prognosis of the disease. Since such genetic changes are central to the initiation and progression of neoplasms, techniques have been developed for their detection and characterization.
Single and simultaneous nucleic acid detection in clinical samples
Authors: Herrington C S , McGee James O'D
Published: November 2023

In situ hybridization (ISH) may be defined as the direct detection of nucleic acids in cellular material. Its application to human pathology, therefore, involves the detection of both normal and abnormal nucleic acids in human cells and tissues (for review see Herrington and McGee, 1992a; Herrington 1994a). The development of techniques for ISH, in the context of pathology, has been directed towards procedures that are clinically useful.
Epilogue
Authors: Walter Lack H , Mabberley David J
Published: November 2023

The Flora Graeca saga neared its end when Platt closed the accounts and transferred the ‘ballance of [£]9 9[s] 2[d] to the Account of Dr. Gibbert late V. C. [Vice-Chancellor] at Mess.rs Child & Co.’; this was done on 29 December 1840, almost forty-five years after the death of Sibthorp, fourteen years after the death of Bauer, and twelve years after the death of Smith. By then the specimens still on loan to Lindley, as well as all the copper plates which had been used for the production of the Flora Graeca, were probably returned to Oxford. Platt paid for the transport of the latter to Oxford on 2 November 1840. A month later, the whole remaining stock of letterpress was sent from London to Oxford, and the receipt acknowledged on 22 December 1840 by P. Bliss, Registrar of the University.’ This consignment may have included a special tribute from Hawkins and Platt for the University, regarded by some in the famous trial as the true publishers of the two works—two complete sets of the Flora Graeca. They were deposited in the Bodleian Library and in the library of the Physic Garden. While the first set was later sold, the latter set is still kept in the library of the Department of Plant Sciences, labelled with a bookplate which reads: ‘Decem haec volumina inter libros bibliothecae horti botanici oxoniensis Johannis Sibthorp. M. D. testamenti curatores Johannes Hawkins et Thomas Platt perpetuo servari voluerunt A. D. MDCCCXL’ [John Hawkins and Thomas Platt, the executors of John Sibthorp M. D., wanted to have these ten volumes permanently preserved among the books of the library of the Oxford Botanic Garden. A.D. 1840].
The ants (Formicidae)
Authors: Longino John T , Hanson Paul E
Published: November 2023

Completely winged (males, and at least for a short time after eclosion, queens) or apterous (workers). Head prognathous in female castes (worker and queen); antennae elbowed, with an elongate basal segment (scape), female castes with 4 to 12 segments, males with 9 to 13 segments. When wings present, the hind wing generally lacking lobes (except in some Ponerinae) and with 0 to 2 enclosed cells present. Metapleural gland present on mesosoma, opening above hind coxa, sometimes the gland secondarily reduced or lost. Metasomal segment I always reduced and isolated from the remaining metasomal segments to form a distinct node or scale (petiole); frequently metasomal segment II also reduced and isolated (postpetiole). Males often bear little resemblance to queens and workers, being smaller, more fragile, and with smaller heads and relatively larger eyes and ocelli.
Classical polyandry: the most puzzling of avian mating systems
Authors: Ligon J David
Published: November 2023

The term polyandry refers to a mating bond between a female and two or more males. Classical polyandry (Oring 1986) is the term used for social-mating systems where (1) a single female mates either sequentially or simultaneously with two or more males during a single breeding season, and (2) males typically form bonds with no more than one female per breeding cycle or per season. A key characteristic of classical polyandry is that each male has its own nest, where it incubates the eggs and later provides care for its (usually) precocial young, most typically with little or no help from the female. In classical polyandry, males not only provide virtually all parental care, females also compete aggressively for mating opportunities. Female-female competition is probably causally related to the reversed sexual dimorphism in body size and often colour seen in such species (e.g. Jehl and Murray 1986).
The Type-Material of Diptera (Insecta) Described by
Authors: Verrall G H , Collin J E , Pont Adrian C
Published: November 2023

G H Verrall and his nephew J E Collin dominated the study of British Diptera (two-winged flies) for a century, and formed what is probably the finest collection of Diptera ever to have been in private hands - it contains a more complete representation of British flies than does the Natural History Museum in London. The collection, now in the Oxford University Museum, is an entomological resource of international standing, as it contains the original material ('types') of the several hundred new species that Verrall and Collin describe. This book is a source-work of information on the Verral-Collin Diptera. For the research worker, it is a catalogue of the 900 species described by Verral and Collin, with an enumeration of the type-specimens located in their collection and in many other museums in Britain, Europe, and North America. For the historian of science, it contains essential historical, bibliographic, and museological information on an important era in British entomology. Appendices include brief biographies of their collecting associates, a classified list of the new species they described, and a list of the British localities at which their new species were found.
Dietary intake and nutritional status
Authors: Galvin Kathleen A , Little Michael A
Published: November 2023

Until the late 1970s, there were virtually no systematic studies of diet and nutrition of African pastoral populations (Little 1980; Wheeler 1980). Some biomedical studies had explored cardiovascular health status of pastoralists within the context of nutrition, but information on dietary intake was based largely on casual observations (Mann et al. 1972; Shaper et al. 1963). Much of this work was founded on the erroneous belief that pastoral groups subsisted almost entirely on milk products and meat, with corre¬ spondingly high fat intakes (Biss et al. 1971; Mann and Shaffer 1966; Shaper and Spencer 1961). After 1980, several comprehensive studies were conducted to assess diets of pastoral populations, including the Sudanese Baggara (Holter 1988), Kenyan Maasai (Nestel 1986), West African Fulani and Tuareg (Benefice et al. 1984; Wagenaar-Brouwer 1985), and Kenyan Turkana (Galvin 1985). Rather than demonstrating uniform diets high in animal products, these studies described remarkable variation in dietary intakes. Variations were observed among ethnic populations; by status within the population; by age, sex, and activities of population members; by season; and by longer-range environmental fluctuations. Based on these studies, the current view of African pastoralists and their dietary patterns is one in which food production and consumption is highly sensitive to the circumstances of their lives, circumstances that include variations in climate, ecology, health, and social and political conditions.
The oil industry, transport, and the environment
Authors: Chase Rodney
Published: November 2023

Mr Rodney Chase is now Chief Executive Officer of British Petroleum (BP) Exploration. When he delivered this lecture, he was the Managing Director responsible for communications, external affairs, and the environment in British Petroleum pie, the company to which he has devoted his entire career. Rodney Chase has exceptional breadth of experience in the oil industry, having held posts within both the Upstream (exploration and production) and the Downstream (refining and marketing) divisions of BP on three continents: Australasia, Europe, and North America. He has served the company in BP Shipping, in Refining and Marketing, in Distribution, in Oil Trading, and in Gas, as well as holding corporate positions in Finance and Strategic Planning. As Chief Executive Offzcer of BP Finance and Group Treasurer, Mr Chase played a key role in the company’s acquisition of The Standard Oil Company and Britoil, as well as in the divestment of BP’s mining interests. Currently, in addition to his responsibilities for exploration, Rodney Chase has Board responsibility for the Western Hemisphere. He is Chairman of the World Business Council for Sustainable Development (WBCSD) and a Member of the UK Advisory Committee on Business and the Environment (ACEE); he also belongs to the UK Round Table on Sustainable Development.
Periglacial terrestrial habitats
Authors: Fogg G E
Published: November 2023

The supply of water, arriving as precipitation, dew, frost, or run-off, is also affected by slope and aspect. Alternation between moist and dry conditions is least severe on horizontal surfaces. In coastal and maritime situations, melt water may trickle over rock surfaces for much of the summer. Crustose or foliose growth will retain water. Mineral nutrients may come in airborne dust, precipitation, run-off or splash, or, from the rock itself. Near bird colonies the nutrient supply may be so copious as to be toxic.
The marine benthic habitat
Authors: Fogg G E
Published: November 2023

Polar land habitats suffer extreme variation of conditions, with desiccation or mechanical damage by wind, unstable substrates, or ice movement, as the usual limiting factors. Shallow inland waters have similar disadvantages. Deeper inland waters afford more stable conditions with steady temperatures and ample water, but tend to be poor in nutrients. Benthic vegetation is frequently the most successful form of life in them. The sea similarly provides stable conditions and temperatures which cannot fall below—2 °C. This is reflected in the circumstance that a majority of polar invertebrates is stenothermal (i.e. unable to survive outside a narrow temperature range), and standing in contrast to the terrestrial organisms such as Nanorchestes (p. 83), which have remarkably wide thermal tolerances. The sea has the additional advantages that there are no solid barriers to transport of nutrients and movement of organisms. On the other hand, mechanical damage by drifting ice can be severe and polar shores usually seem barren, all exposed life down to several metres being battered and scraped off (Fig. 6.1). Icebergs may plough up the seabed down to 300m or more. Nevertheless, benthic life is abundant in polar seas.
The Deep-sea Dimension
Authors: Herring Peter
Published: November 2023

Look out across the ocean on a calm day, from the shore or from the deck of a ship. The vista is daunting in its scale yet innocuous in its features. But beneath this tranquil skin lies a teeming horde of organisms, from the tiniest viruses to the mightiest whales, all of which are continually influenced by the physical features of the seawater within which they move -and by which they are moved. Evolution occurs apace: ‘ Even the most peaceful place is full of strife, with any weakness of its inhabitants at once exploited’ Gones 1999).
Size, Sex, and Seasonality
Authors: Herring Peter
Published: November 2023

Growth and reproduction are the keys to the success of individuals and the evolution of species. How are they affected by life at depth? The deep sea is not a uniform habitat, either in its physical features (Chapter 1) or in the consequent patterns of biogcography and variations in biodiversity (Chapters 4 and 11).
Running water habitats
Authors: Giller Paul S , Malmqvist Björn
Published: November 2023

The landscape across which rivers and streams flow is formed through geo¬ morphological and geological processes. Landforms arc built up through sedimentation and geological activity driven by volcanism and continental drift and are eroded by wind, ice, and water. These complex processes together determine the outlines of the catchments within which precipitation falls, flows downhill, and ultimately forms the physical channels of running waters. Rivers arc dynamic systems that are born and age. Ageing involves continuing erosion or the stream channel back towards the source or out onto the floodplain. Erosion is greatest in certain areas (e.g. China, the south-eastern United States) which is shown in the rivers’ particularly heavy silt loads. Typically, river channels have extended lifespans compared to lakes. The world’s really large rivers, along with their great age and diversity, also have many unique organisms and a myriad of ecological processes that have a significant influence over the entire catchment system they drain. Unfortunately, these systems have suffered more than any other from man’s influence, and few remain in a natural, unaffected state.
Evolution, systematics and biogeography of Palaearctic vipers
Authors: Nilson Goran , Andren Claes
Published: November 2023

Very few synapomorphies have been proposed for the ‘Eurasian group ‘ (Vipera s. l., Eristicophis and Pseudocerastes) within the Viperinae. Several studies have demonstrated difficulties in distinguishing the group in cladistic terms. However, different species groups show monophyletic patterns. The different spectra of habitat choice, altitude and latitude distributions, reproductive strategies etc. are analysed, and various phylogenies as well as the evolutionary history of lineages within the group are re-examined.
Growth and survival of Vipera berusin a variable environment
Authors: Forsman Anders
Published: November 2023

Data from a capture-mark-recapture study (1986-1994) of a population of adders Vipera berus inhabiting a group of islands off the Swedish east coast in the Baltic Sea are used to examine whether changing food availability and weather conditions influence growth and survival of large relative to small individuals. Mean air temperature and population density of the field vole Microtus agrestis, the primary prey for adders, were used as measures of weather conditions and food availability, respectively.

The relationship between growth rate and body size varied significantly among years, but was parallel in males and females. Large and small snakes responded differently to changes in vole densities; growth rates decreased at a slower rate with increasing body size when voles were abundant than when voles were scarce. There was no effect of changing weather conditions on adder growth rates.

Logistic regression analyses of recapture data revealed that survival probability of adders increased with increasing body size in some years and decreased with increasing body size in other years. The survival advantage of large body size tended to increase with increasing food availability, but was not affected by changing weather conditions. Within any given year, the relationship between survival and body size was similar in the two sexes.

Years characterized by rapid individual growth rates were associated with a subsequent reduced survival probability of large relative to small snakes, a pattern that should prevent consistent shifts in body size through time. Although an observed lack of variation in mean body size of female adders across years corroborates this prediction, mean body size of male adders increased significantly during the nine years of the study.
Molecular evolution of phospholipase A2s and metalloproteinase/ disintegrins from venoms of vipers
Authors: Moura-Da-Silva Ana M , Theakston R D G , Crampton Julian M
Published: November 2023

The evolutionary relationships of venom toxins have been studied by independently analysing venom group II phospholipases A2 (PLA2s) and mammalian and snake venom metalloproteinase/disintegrin/ cysteine-rich (MDC) families of proteins. Phylogenetic trees grouped both venom group II PLA2s and MDC proteins according to current taxonomic divisions and/or functional activities. Gene duplications may have occurred at different points during the evolution of these protein families. The pattern of variability of the cDNAs coding for venom toxins has also been analysed. The greatest sequence variation of venom group II PLA2s has been observed in the region coding for the mature protein, with most of the substitutions occurring in non-synonymous positions. In MDC proteins, the snake venom metalloproteinase domain appears to be the most variable, whilst neutral selection appears to be responsible for the evolution of the mammalian proteins, the only exception being the region comprising the catalytic site of the mammalian metalloproteinase domain. These data suggest that gene duplication followed by hypervariability of the amino acids in the functional domains and positive selection may have occurred during the evolution of venom toxins, assisting the generation of diversity in these protein families.

Snake venoms are complex mixtures of proteins with different toxic or enzymatic properties. The type of toxic activity of the venoms appears to reflect their taxonomic classification; for example, Elapidae and Hydrophiidae venoms are generally neurotoxic whilst Viperidae venoms are more complex, including a number of enzymes that may induce local tissue damage, haemorrhage and often also coagulopathy (Warrell 1983). In the Viperidae these enzymes generally belong to few gene families. The most important of these, as far as toxicity is concerned, are the proteinases and the phospholipases A2 (PLA2s). Proteinases acting .on different substrates, or PLA2s with different tissue specificity, have often been reported in viper venoms (Kini & Evans 1989; Bjarnson & Fox 1994).
The kinetics of snakebite envenoming and therapy
Authors: Theakston R D G
Published: November 2023

Treatment of systemic envenoming is related to the neutralizing efficacy of the antivenom used, the route by which it is administered and the dose. In the past, treatment of patients has depended almost entirely on the individual clinician ‘s experience in assessing the severity of envenoming. The development of enzyme immunoassay has enabled a more scientific appraisal of the situation, allowing the accurate estimation of circulating specific venom and antivenom levels at any time in the patient ‘s blood and other body fluids. It is therefore possible to measure accurately the efficacy of antivenom in the neutralization and clearance of venom antigen. In Brazil it has been shown that clinicians are treating patients with excessive amounts of highly efficient Bothrops polyspecific antivenom, with a resulting unacceptably high incidence of early anaphylactic reactions and, in Sri Lanka, the use of imported Indian antivenom is relatively ineffective in neutralizing the venoms of Sri Lankan snakes, demonstrating the real problem of venom variability within individual species. For example, Indian Russell ‘s viper venom does not possess the neurotoxin present in the venom of the Sri Lankan subspecies. In West Africa the improved clearance of venom when a monospecific Echis antivenom is used in the treatment of Echis ocellatus envenoming, compared with that of the polyspecific antivenoms currently in use, has been demonstrated. Such clinically-based immunological studies provide an objective assessment of antivenom therapy which has not in the past been feasible. This should result in more efficient and controlledust of expensive antivenoms for treatment of systemic envenoming. Such studies also emphasize the importance of individual countries producing their own antivenoms for treatment of snakebite.
Tinamous
Authors: Davies S J J F , Bamford Michael J , Loomes Danika
Published: November 2023

Ranging in size from 1 S to 50 cm, males and females usually look alike, but the females are slightly larger and often a little more colourful than the males. All are ground-dwelling but capable of flight, resembling quail and partridges, although they are not related. The bill is thin and slightly curved, the head is small and the neck is thin. The rear part of the body seems to be high, owing to the great development of rump feathers; these often hide the very short and soft tail. The thick legs are built for running; there are three short front toes, the hallux being either elevated or absent.
The Quantum Atom
Authors: Bader Richard F W
Published: November 2023

Lewis introduced the concept of the electron pair into chemistry in 1916. In this paper (1916) he was able to rationalize the known geometries of carbon compounds by replacing the prevailing notion of a cubical arrangement of an octet of electrons by a tetrahedral arrangement of four pairs of electrons. What particularly served to later convince Lewis (1933) of the potential of the new quantum mechanics, as evidenced by the opening quotation, was its ability to account for observed molecular geometries and so provide a theoretical basis for his electron pair model. The early development of the valence bond theory of directed valence by Slater (1931) and Pauling (1931, 1960) provided the first quantum mechanical rationalization of molecular geometry. The valence bond approximation to the wave function, as expressed in terms of the overlap of hybridized atomic orbitals to describe the pairing of electrons, coupled with the notion of electron spin, was the natural theoretical extension of the pair concept of Lewis. The hybrid orbitals were spatially localized in directions coincident or nearly coincident with observed molecular geometries and this gave theoretical substance to the notion of picturing a bond as a spatially localized pair qf electrons. Pauling’s emphasis of the use of ionic-covalent resonance structures to account for the differing character of bonded interactions was in turn a restatement of Lewis’s idea to represent the bonding between a pair of atoms in terms of tautomeric extremes of electron-sharing possibilities. It was a principal claim of Lewis’s first paper (1916) that ‘According to the theory which I apply now presenting, it is not necessary to consider the two extreme types of chemical combination, corresponding to the very polar and the very nonpolar compounds, as different in kind, but only as different in degree.’
The representation of space groups: an example
Authors: Altmann Simon L
Published: November 2023

A remarkable property of space groups was discovered in Chapters 5 and 6. If, given a space group G, we obtain bases for all the irreducible representations of its translation subgroup T, then from these bases (which are the Bloch functions), bases of the representations of G can be constructed which have two properties: they are irreducible and they are complete (that is, they span all the irreducible representations of G). This result is of major importance since the bases for the irreducible representations of G in which we are interested are the energy eigenfunctions, but it is a difficult result to prove. We shall provide in this chapter an example which will allow the reader to verify that the method given in Chapters 5 and 6 actually works, and which will help to consolidate some important concepts such as those of stars, small representations, degeneracies and bands. Except insofar as it might be required in order to build up experience in these topics, this chapter will not be necessary for the rest of the book, so that the reader who feels already sufficiently confident about the methods so far developed can proceed straightaway to Chapter 8 and return to the present chapter at any later time.
Bands and Fermi surfaces in metals and semiconductors
Authors: Altmann Simon L
Published: November 2023

Although quantitative methods for the calculation of band structures will not be discussed until Chapter 10, we shall give here a few important examples of their applications, since we already have the tools for understanding these results. This will provide better continuity with the methods so far studied for the description of bands. We shall first consider a semiconductor, silicon, for which at absolute zero the whole of the Brillouin zone is fully occupied. (As it is now standard practice in describing computed bands, the reduced band scheme will be exclusively used for this purpose.) After this, the noble metal copper will be treated and, since the Brillouin zone is only partly occupied here, the Fermi surface will also be discussed. The example of copper will allow us to understand also the qualitative features of the bands in simple metals (like the alkalis) and in transition metals (like nickel).
What porphyrins are and what they do
Authors: Milgrom Lionel R
Published: November 2023

What’s in a name? Names are important because they can tell us what things are, and what they do. Above all, names tell stories. Take the word porphyrin for instance. In a strictly chemical sense, this word has an exact meaning. It is the name given to a family of intensely coloured compounds, at whose heart is a large macrocycle of twenty carbon atoms and four nitrogen atoms. The macrocycle is itself built up from four smaller rings, each made up of four carbon atoms and one nitrogen atom. Each of these rings is joined to its neighbour by one bridging carbon atom So much for the chemical definition. Hidden within it is a vast chunk of history, stretching back to the beginning of civilisation in the Eastern Mediterranean.
…And where porphyrins go to
Authors: Milgrom Lionel R
Published: November 2023

The great science fiction writer Arthur C. Clarke once wrote that behind every living human being stands a hundred million ghosts. It is another way of saying that living things die and replace themselves. But it’s not only living things (right down to the lowliest virus) that turn themselves over. Many of the molecules that control biological activity do the same thing and porphyrins arc a good example of this. Red blood cells live for about three months in the bloodstream, carrying oxygen around the body, before becoming senescent. They are then transported to the liver where they are dismantled. During this process, the heme is broken open to release the iron, which is either excreted or saved depending on the body’s reserves of the metal. After several further transformations, the remains of the heme are excreted from the body.
Intermolecular interactions in the crystals of simple cyclic β-diketoalkanes
Authors: Katrusiak Andrzej
Published: November 2023

The crystal structures of several simple cyclic βdiketoalkanes have been studied at high pressures; they include 1,3-cyclopentanedione (hereinafter CPD), 1,3-cyclohexanedione (CHD) and 2-methyl-1,3 cyclopentanedione (MCPD). In the crystalline state the molecules of these compounds are present in enol form and are linked by short (Table 1) asymmetric and nearly linear hydrogen bonds. Several features are common to these structures: the molecules are hydrogen-bonded into chains, the conjugated π-electron bond system and the enolic hydrogen atom (O=C-C=C-OH) as well as the adjacent atoms form a planar fragment of the molecules, the molecules in one chain are coplanar, the chains of the molecules are arranged in the crystals in such a way that each chain has one neighbouring chain on each side forming sheets of chains.
Tutorial on automated Patterson interpretation to find heavy atoms
Authors: Sheldrick G M
Published: November 2023

The algorithms employed for automatic location of heavy atoms via the Patterson function in the programs SHELXS-86 and SHELXS-90 are discussed, and are illustrated in the form of two tutorial exercises. As a small molecule crystallographer participating in a macromolecular computing school, I have tried to choose a topic of importance to both small molecule and macromolecular crystallographers, namely the location of heavy atoms via the Patterson function. In the case of heavy atom derivatives of proteins this Patterson would be calculated using the isomorphous difference structure factors. At least a quarter of organic and inorganic structures are solved by the heavy atom method, and the preparation of heavy atom derivatives is almost obligatory for proteins if no suitable search model is available for molecular replacement. Despite this, there is a striking lack of user-friendly computer programs, general for all space groups and types of problem, for the automatic location of heavy atoms, in sharp contrast to the situation in small-molecule direct methods. This seems to be simply an historical accident; the necessary theory has be well understood for at least 40 years, and the computer resources required are modest.
Exponential density: exact fitting of structure moduli by entropy maximization
Authors: Collins D M , Prince E
Published: November 2023

Electron density given as an exponential function can be made to fit subsets of structure moduli exactly by a constrained nonlinear optimization. A dual method is used in which the problem is solved in a space of dimension equal to the number of structure factor constraints. Entropy is the objective function to be maximized. On the joint basis that density must be everywhere positive and exactly match the experimental constraints, the result is shown to be the most general obtainable from an initial phase assignment. If there are other acceptable maps, they cannot be as flat as the electron density map given by this algorithm.
Modelling the architecture of large RNA molecules: a three-dimensional model for group I ribozymes
Authors: Westhof E , Jaeger L , Dumas, P , Michel F
Published: November 2023

Approaches for modelling proteins and nucleic acids are discussed in parallel. While knowledge-based modelling is nowadays the most powerful method for proteins, it is yet inadequate for nucleic acids. For modelling nucleic acids, especially RNA molecules, one has to rely either on chemical and enzymatic probing at the nucleotide level or on comparative sequence analysis if enough sequences with appropriate randomness are available. With either method, one can hopefully obtain sufficient information not only for determining the 2D structure but also for constructing the 3D architecture of complex RNA molecules. ‘ The application of comparative sequence analysis together with graphic modelling to group I ribozymes is presented.
Development of indigenous technology for the manufacture of modern silicon materials
Authors: Murthy A R Vasudeva
Published: November 2023

The importance of modern silicon materials to the industrial development of India was realized by the scientists in the Departments of Inorganic and Physical Chemistry and Physics at the Indian Institute of Science in Bangalore over three decades ago. A programme was initiated for the standardization of preparative methods for high purity silicon compounds on a laboratory scale. The technical know-how generated at the Institute has since been transferred to industry for the manufacture of a few of these silicon compounds, which include silicon tetrachloride and ethyl silicate-40. The scale of operations for these compounds runs into hundreds of tons per year. In quality, they conform well to international standards and are also competitive with regard to price in the world market. These two products not only meet the current industrial needs of the country, but also serve to meet the growing demands of a number of industrially advanced countries. Further collaborative programmes with industry are in progress. The industry has put up a plant to manufacture about 30 tons yr- of polycrystalline silicon and 10 tons of electronic grade silicon for single crystals and wafers. Other silicon materials like silane, fumed silica, silicon nitride, etc. are also under development.
Binary systems, Bakhuis Roozeboom diagram
Authors: Koningsveld R , Stockmayer W H , Nies E
Published: November 2023

The phase rule (59) reads f=4 −Pfor binary systems, and we therefore have the following possibilities for phase equilibrium:

One-phase equilibrium: f= 3; freedom of choice for p, T, and x  2; three-dimensional regions in p(T, x  2) space; trivariant equilibria.

Two-phase equilibrium: f= 2; freedom of choice for the possible combinations ( p, T), ( p, x  2), or (T, x  2); ruled surfaces in p(T, x  2) space; bivariant equilibria.

Three-phase equilibrium: f= 1; choice of one intensive variable fixes the other two; space curves in p(T, x  2) space; univariant equilibria.

Four-phase equilibrium: f= O; non-variant equilibrium, only at a single set of values of p, T, x  2; a quadruple pointin p(T, x  2) space.

If a vapour phase is involved, it is customary to use the index 1 to denote the more volatile of the two components.
Physical Adsorption: Forces and Phenomena
Authors: Bruch L W , Cole Milton W , Zaremba Eugene
Published: November 2023

About twenty years ago, as a rapid expansion of surface physics was underway, Greg Dash and Bill Steele published a pair of influential monographs on physical adsorption defining the language and identifying a family of issues that are common to most work in the field. In the intervening years, many workers have contributed to the growth of understanding of physical adsorption. At present, we appear to be in a period of consolidation and it seemed appropriate to us to attempt a monograph that would incorporate the progress that has been made. This book is the result of our efforts.
Monolayer Examples
Authors: Bruch L W , Cole Milton W , Zaremba Eugene
Published: November 2023

In this chapter we survey several examples of physically adsorbed monolayers chosen according to two criteria: (1) to demonstrate the interesting variety of physical phenomena present and (2) to illustrate the outstanding features of the general theory in Chapters 4 and 5. Fluid phases (dilute gases and liquids) have correlation lengths that usually are small except near the gas-liquid critical point, but in the monolayer the correlation length may reach thousands of angstroms near a melting transition (Specht et al. 1985; Nuttall et al. 1994). Further, the spatially periodic external potential arising from the substrate lattice may cause the fluid density to be quite nonuniform. The solid phases have sharp diffraction patterns and present a most diverse set of structures in the monolayer regime; we emphasize the types of lattices and their evolution under increased temperature and lateral stress.
Peptide bond formation
Authors: Jones John
Published: November 2023

A very wide variety of reactions which lead to the generation of amide functionalities is available: a valuable survey of these reactions, in the context of organic chemistry as a whole as opposed to the narrower area with which we are concerned here, was published in 1971.
Travelling Waves
Authors: Gray Peter , Scott Stephen K
Published: November 2023

In the previous chapter we dealt with the existence and spontaneous formation of stable spatially non-uniform patterns. Here, we consider another form of spatial behaviour. We envisage a (long) tube, initially containing a spatially uniform distribution of reactants. The spontaneous reaction converting these reactants to products is exceedingly slow but can be initiated at one end, perhaps by the local addition of some key intermediates (such as an autocatalyst), by local heating, or by a spark (which often serves to achieve both of the former). We are interested to see if and how the reaction can then propagate along the whole length of the tube. Uthe reactants are gaseous and the process is exothermic, the reaction zone will typically move quickly and we talk of a flame. For reactions in dilute solutions the propagation is typically much slower, and we talk of a chemical wave.
Principles of Nuclear Magnetic Resonance in One and Two Dimensions
Authors: Ernst Richard R , Bodenhausen Geoffrey , Wokaun Alexander
Published: November 2023

Nuclear magnetic resonance spectroscopy is one of the most powerful and versatile techniques now available for the study of molecular structure and reaction mechanisms. Written by recognised experts in the field, this classic account of modern NMR spectroscopy was heralded on its first publication in 1987 as "the lasting text of its age" Nature. Now available in paperback, it provides a thoroughly comprehensive review of modern NMR techniques and the underlying principles. It describes the study of solutions and solids using one- and two-dimensional spectroscpy, providing both a solid theoretical foundation and a description of practical procedures. The material is presented in an intuitive manner within a rigorous mathematical framework, and is extensively illustrated throughout. This important work was written at the ETH in Zurich, one of the world's leading institutions in advanced NMR methods, which has played a key role in the development of Fourier spectroscopy, two-dimensional spectroscopy, and Fourier-transform NMR imaging. Available in paperback for the first time, the book provides the definitive account of the field, and is without question "a must.....for every self-respecting NMR spectroscopist" Journal of Magnetic Resonance.
Multiple Quantum Coherence And Applications
Authors: Goldman Maurice
Published: November 2023

In the following it will be necessary to distinguish positive from negative multiple quantum coherence. The somewhat arbitrary convention is that +k quantum coherence corresponds to matrix elements of the form (8.3), that is to the case when a contains operators which, when acting on some kets, raise m by k units. Likewise, -k quantum coherence corresponds to matrix elements of the form (8.2). We give below some examples of the order of coherence produced by operators present in the density matrix: