bluuebunny/crossref_metadata_2025_split huggingface dataset:
Economic importance of Hymenoptera
Authors: Hanson E 
Published: November 2023

Abstract
From the human perspective, no other group of insects contains so many beneficial species as the order Hymenoptera. The majority of hymenopterans have larval stages that are carnivorous on other insects and numerous species are vital in controlling the populations of pest insects. Among the non carnivorous members of the order, bees constitute the single most important group of plant pollinators. One species of bee, the honey-bee, is the most prevalent domesticated insect and provides us with honey, wax, and other products. On the other hand, the order Hymenoptera also contains some very serious pest species. Leaf-cutting ants are among the most damaging agricultural pests in the Neotropics. Many ants, wasps, and bees are capable of inflicting painful stings, and in persons who develop a hypersensitive reaction to the venom, a sting can be fatal.
The orussids and stephanids
Authors: Hanson Paul E , Gauld Ian D 
Published: November 2023

Abstract
The traditional division of the order Hymenoptera into two suborders, the ‘Symphyta ‘ and Apocrita, is increasingly difficult to maintain since the characters used to unite the ‘Symphyta ‘ are mostly shared plesiomorphies. Moreover, there are several apomorphic characters that unite the Orussidae with the Apocrita, although orussids are usually classified in the ‘Symphyta ‘ (see Chapter 5). In our opinion, these features coupled with the fact that orussids develop as parasitoids, are an overwhelming argument for treating the Orussidae separately from the sawflies and woodwasps, thereby breaking with the convention of maintaining the symphytan/ apocritan divide. Although the Orussidae and Stephanidae probably do not comprise a monophyletic group, they are both primitive families of parasitoids. Both comprise species that are idiobiont ectoparasitoids of wood-boring insects, which is thought to be the ancestral biology of Apocrita (Gauld, 1988c). Therefore, if for no other reason, it is biologically convenient to treat these two families together.
Male mate choice and intrasexual competition
Authors: Ligon J David 
Published: November 2023

Abstract
This chapter deals briefly with two other issues that, together with female mate choice, make up the subject of sexual selection. The first is mate choice by male birds. In contrast to female mate choice, this subject has received little attention. The second topic, intrasexual competition for mates and matings, is widely recognized as extremely important in the lives of vertebrate animals. Nevertheless, it too has received far less attention than mate choice by females. Typically, such competition is among males; female-female competition, however, can also be intense in birds and is sometimes even fatally violent.
Cooperative breeding
Authors: Ligon J David 
Published: November 2023

Abstract
Cooperative breeding, sometimes referred to as communal breeding, is a rare and specialized phenomenon that occurs in fewer than three per cent of the world’s approximately 9700 species of extant birds. Cooperative breeding is defined by the presence in a stable social unit of non-breeding ‘helpers’, which assist in the care of young birds, in addition to breeding individuals (from a single pair to several or even most group members).
Migration across ecosystem boundaries
Authors: Dyson-Hudson Rada , Meekers Dominique 
Published: November 2023

Abstract
Migration across ecosystem boundaries is the third parameter which determines population replacement and persistence, the others being fertility and mortality. Migration can contribute either to population increase or population decrease. Because migration is reversible—people who leave can later return—and because migration rates can change rapidly, it would seem to be an effective mechanism for maintaining a balance between people and resources in a highly fluctuating environment like South Turkana. McCabe (1984, 1987) documented the importance of short-term movement by marginal people out of the pastoral sector as a mechanism of coping with drought. In this chapter, we focus on longer-term migrations out of the pastoral sector for one year or more, and discuss the effects on ecosystem function of both short-term and long-term migration across the boundaries of the South Turkana pastoral production system.
Targeting the tumour endothelium using specific antibodies
Authors: Derbyshire Elaine J , Thorpe Philip E 
Published: November 2023

Abstract
Monoclonal antibodies have been considered for many years as a means to deliver cytotoxic agents specifically to tumour cells. While the approach has proved promising in clinical trials of leukaemia and lymphoma (1,2), the results of antibody trials in solid tumours, which account for 90% of malignancies (3), have so far been disappointing (4,5).
The Biology of Polar Habitats
Authors: Fogg G E 
Published: November 2023

Abstract
This book is unique in providing a comparative overview of life at the two Poles, from ice caps to tundra and open ocean. It describes their physical characteristics, the communities of microorganisms, plants, and animals inhabiting them, and their interactions with the global environment. Fogg considers the origins of polar habitats, their subsequent colonization and population dynamics, and assesses the effects of human activities on the Pole, focusing on the changes that may result from global warming and stratospheric ozone depletion. The author has wide experience in marine and terrestrial ecology, and his background of research in both the Arctic and Antarctic is reflected in the book. This is the most authoritative and up-to-date volume currently available on polar biology. The text is clear and lively, well illustrated, and supplemented with ample references for further reading. It provides and excellent introduction for anyone intending to work in the polar regions, and will be ideal for students taking undergraduate and post-graduate courses in biology, ecology, microbial ecology, geography, and conservation.
Sound production and acoustic communication in Xenopus borealis
Authors: Yager David D 
Published: November 2023

Abstract
Xenopus has an underwater acoustic communication system based on simple clicks arranged in different temporal patterns. Focusing on X. borealis, I have found a sound production mechanism highly adapted to the underwater environment-in contrast to terrestrial anurans, these frogs do not use a moving air column to produce their vocalizations. The larynx of the male is enormously enlarged to form an internal vocal sac. The arytenoid cartilages are modified to form two discs whose smooth medial surfaces are normally tightly apposed. When contraction of bipennate laryngeal muscles causes the discs to separate with high acceleration, a single click results. The click is most probably produced by an ‘implosion’ as air rushes into the cleft between the discs. The frequency spectrum of the click is determined by the vibrational characteristics of the laryngeal walls.
The biology of Xenopus tadpoles
Authors: Wassersug Ichard 
Published: November 2023

Abstract
Virtually all that is known about the biology of Xenopus larvae comes from laboratory studies of one species, Xenopus laevis. This account reviews several aspects of larval biology, especially feeding, respiration, schooling behaviour, swimming mechanics and certain visceral functions. Compared to tadpoles in other genera, Xenopus larvae are highly specialized, obligatory microphagous tadpoles. Many of their unique morphological features testify to their efficiency as suspension feeders. Xenopus larvae are also obligatorily air-breathers and must intermittently surface for air in order to have normal growth rates. Xenopus tadpoles are social and use both visual and lateral line information to maintain school geometry.
Skin secretions of Xenopus laevis
Authors: Kreil Gunther 
Published: November 2023

Abstract
A variety of peptides, enzymes and other proteins have been isolated from skin secretions of Amphibia. Among the peptides at least three different groups can be discerned: (1) those with structural and functional homology to mammalian hormones and neurotransmitters; (2) antimicrobial peptides of different types, one being characterized by the propensity to form amphipathic helices; and (3) opioid peptides containing a D-amino acid essential for biological activity, for which no mammalian counterparts have so far been found. Of the first group, thyrotropin releasing hormone, caerulein (related to mammalian cholecystokinin) and xenopsin have been isolated from skin secretions of X. laevis. cDNA cloning has been used to elucidate the structure of the precursors of these peptides. Moreover, the antimicrobial peptides PGS/magainins I and II, PGLa and several others have been studied in detail. Several enzymes involved in the processing of peptide precursors to the final product have also been isolated from skin secretions of X. laevis.Recent studies with skin secretions of frogs from other families of amphibian species have yielded similar results. These have also been found to contain numerous peptides; in particular, a large number of peptides with antimicrobial properties have been discovered in the past years.
Immune system of Xenopus: T cell biology
Authors: Horton John D , Horton Trudy L , Ritchie Pamela 
Published: November 2023

Abstract
Evidence for T and B lymphocyte populations in Xenopus is reviewed, and attention is focused on the recent creation of monoclonal antibodies that identify T cell surface markers. A second section summarizes evidence for T helper and T cytotoxic lymphocytes and their genetic restriction, discusses the role of T cells in transplantation immunity, and outlines studies on T cell-derived cytokines. A third section considers the biochemistry, cell distribution and ontogeny of Xenopus major histocompatibility com¬ plex (MHC) proteins; implications for T cell functioning of the differences in MHC antigen expression between larvae and adults are discussed. The role of the thymus in T cell development is then dealt with in detail. After considering the embryological origins of thymic lymphocytes, describing thymus histogenesis and discussing T cell changes during ontogeny, the possibility of extrathymic development of some ‘T-like’ cells is discussed in the light of recent flow cytometric studies on early-thymectomized (Tx) Xenopus. This fourth section also describes experiments probing the role of the thymus in establishing negative and positive selection of T-lineage lymphocytes. The final section deals with establishment and characterization of peripheral tolerance, following grafting of larvae with allogeneic tissues, and discusses immunoregulatory events occurring during metamorphosis.
The fossil record of the Pipidae
Authors: Baez Ana Maria 
Published: November 2023

Abstract
Pipids have a relatively good fossil record, providing evidence of their evolutionary diversification. The oldest remains referred to this well-corroborated monophyletic group are from the Lower Cretaceous (around 120 Ma) of the Near East. Although their referral to the Pipidae may be questioned, they document the presence of primitive pipoids in the northern margin of Gondwana. All other fossils that clearly belong to this family have been found either in Africa or in South America, where they occur today. Moreover, their former geographical distribution on these continents was more extensive than is their current distribution.
Phylogenetic relationships of the ‘Agkistrodon complex ‘ based on mitochondrial DNA sequence data
Authors: Parkinson Christopher L , Moody Scott M , Ahlquist Ion E 
Published: November 2023

Abstract
We investigated phylogenetic relationships among 15 species of pitvipers commonly known as the ‘Agkistrodon complex ‘ or the tribe Agkistrodontini. We sequenced a 505 base-pair region of the mitochondrial 16S ribosomal DNA for all genera of this group, including all three New World species of the genus Agkistrodon and four members of the Old World Agkistrodon, to test the monophyly of this genus. Results indicate that Agkistrodon is paraphyletic, therefore the genus Gloydius should be used for the Old World members. The genera Calloselasma, Deinagkistrodon and Hypnale are separate lineages, thus their status as genera is upheld. The tribe Agkistrodontini is not valid and the name should be suppressed.
New perspectives on the evolution of south-east Asian pitvipers (genus )Trimeresurus from molecular studies
Authors: Malhotra Anita , Thorpe Rogers. 
Published: November 2023

Abstract
The genus Trimeresurus contains about 36 species, several of which are remarkably similar in superficial appearance, and it is unclear whether this similarity relates to phylogenetic relationships or to ecological convergence. Whatever the cause, it has resulted in considerable confusion which hinders the understanding of the evolution o:f the genus by biologists as well the advancement of snakebite treatment by medical workers. Our ongoing study of this group (part of a larger study of the systematics of medically significant snakes) focuses on a core group of species (T. albolabris, T. popeorum, T. stejnegeri, T. erythrurus, T. macrops) known to be or potentially sympatric in Thailand and adjacent areas and involves the use of multivariate morphometry and mitochondrial DNA analysis to study both inter- and intraspecific relationships. We propose a preliminary phylogenetic hypothesis for a set of species based on PCR-RFLP of the cytochrome b gene of mitochondrial DNA and discuss this in relation to its ability to shed light on morphological evolution in the genus. We then illustrate geographic variation in morphology of T. albolabris, a species with a large range, and relate this to current subspecies and to the phylogenetic history of populations as revealed by cytochrome b sequencing. Mantel tests are used to evaluate various causal relationships.
Cassowaries
Authors: Davies S J J F , Bamford Michael J , Loomes Danika 
Published: November 2023

Abstract
Large, cursorial, flightless birds from northern Australia, New Guinea and adjacent islands (to which they were probably introduced). Bill as long as head, compressed, with the culmen curved to the tip. Nostrils in broad membranous groove in the middle of the bill. Head ornamented with an elevated helmet; head and neck bare, often brightly coloured, with wattles on the neck. Wings rudimentary, with 5-6 strong rounded shafts without webs; tail not apparent.
Introduction to Heterogeneous Catalysts
Authors: Sleight Arthur W 
Published: November 2023

Abstract
An aspect of inorganic solids that has frequently been neglected by solid state chemists is the catalytic property. The reason for this neglect can be primarily attributed to the great difficulty of achieving a detailed understanding of surface structure and reactivity. Certainly, it has been true that reliable mechanistic information on heterogeneously catalysed reactions is rarely achieved. Even on an empirical level, good correlations between catalytic properties and the chemistry of the catalyst itself have been largely lacking. Fortunately, advanced techniques and instrumentation for microstructure and surface studies are now allowing rapid strides to be made in the area of heterogeneous catalysis. Indeed, many obvious and potentially highly revealing experiments within our grasp are waiting to be done. Surface properties of solids are of paramount importance for heterogeneous catalysis. One would like to know the active site density on each crystallographic surface of a solid, and one would also like to know if these active sites are related to dangling bonds due to coordinatively unsaturated surface sites or if they are related to special defects. In a few cases, we are beginning to obtain answers to these questions, and the rate of progress is increasing.
Scissor-type hosts: molecular design and inclusion behaviour
Authors: Weber Edwin 
Published: November 2023

Abstract
It is clear that clathrates and related lattice inclusion compounds are substances now less commonly found by accident, but are more often the products of rational design and synthesis. This is witnessed by a number of examples in the recent literature. Developments are mostly based on a particular overall shape and significant geometry of the so-called host molecule. Examples are the ‘hexa-hosts’ or ‘spiders’, ‘paddle-wheel’ hosts, ‘wheel-and-axle’ hosts, ‘wine cup’ hosts,‘tub’-like, ‘scissor’-type, and ‘roof-shaped hosts. Since the objects connected with the approximate shape of these host molecules have a well-defined symmetry, relationships between host symmetry and clathrate formation are obvious. Thus, projection to a molecule possessing a given symmetry operation is another leading idea of recent host design. On the other hand, it has been realized that directed formation of stable and highly selective clathrates also requires specific binding forces between host and guest stronger than van der Waals interactions. Consequently, a concept based on specific host-guest interactions of dipolar and/or coordinative nature was developed.
Intercalates of zirconium phosphates and phosphonates
Authors: Alberti Giulio , Costantino Umberto 
Published: November 2023

Abstract
Tetravalent metals such as Zr, Ti, Sn, Ce, Th, etc. can be bound to oxygens belonging to XO4 and/or RXO3 groups (X = pentavalent element; R =inorganic or organic group such as -H, -OH, -CH3, -C6H5, etc.) and from such a combination many fibrous, layered, and three-dimensional structures can be obtained. Furthermore, if the oxygens belong to R(XO3)i groups, very interesting layered structures, in which the layers are covalently bonded by the R group acting as pillars, may be formed. The structural features, physicochemical properties, and applications of this rapidly growing class of compounds have been the subject of chapters in books and recent reviews.1-10 Owing to their importance in intercalation and insertion chemistry, we shall in this chapter be concerned almost exclusively with layered structures, including those having layers covalently bonded by R pillars. As regards fibrous and three-dimensional structures, therefore, the interested reader is referred to a number of reviews29 and papers11-14 on these subjects.
Recent advances in the X-ray analysis of cyclodextrin complexes
Authors: Harata Kazuaki 
Published: November 2023

Abstract
Cyclodextrins are cyclic oligosaccharides consisting of six or more a-1,4-linked o-glucose units. These bucket-shaped macrocyclic molecules have a cylindrical cavity with a diameter larger than 5 A and a depth of7-8 A. The inside wall of the macrocycle is comprised of many methylene and methine groups, whereas at both ends of the cavity hydroxy groups are found in a circular arrangement. Therefore, the cyclodextrin cavity exhibits hydrophobic character and favourably accommodates the hydrophobic portion of the guest. Cyclodextrins form inclusion complexes rather nonspecifically with a wide variety of guests of suitable size and shape. Because of the rigid structure of cyclodextrin molecules, the size and shape of the interior cavity are strictly confined by the number of constituent glucose units and complex formation is highly stereoselective, that is, guest molecules or groups should fit into the host cavity, even if only partially.
Chemical sensors
Authors: Lockhart Joyce C 
Published: November 2023

Abstract
A chemical Rip van Winkle awakening today from his extended sleep and examining the chemical scene, would surely be most struck by the chemist's ability to design molecules for a purpose. The able chemist can today essentially design and synthesize molecules to order. For the current generation of chemists the new horizons are the multi-molecular assemblies which can provide analogues of a biological unit. In the area of chemical sensors, the syntheses which chemists are struggling to effect should unite a chemical entity capable of recognition with a signal-processing entity capable of transmitting a signal consequent upon the recognition.
The Colours of Life
Authors: Milgrom Lionel R 
Published: November 2023

Abstract
Why are leaves green and blood red? The answer lies with one family of pigments, the porphyrins and their relatives. These pigments are also responsible for the fundamental energetic processes that make life as we know it possible. The properties of these colorful molecules are now being investigated for use in a wide range of applications, from cancer therapy to microelectronics. The Colours of Life is intended to be an introduction to the porphyrins and their role in life.
Reliability of structure determinations by microwave spectroscopy
Authors: Eijck Bouke P van 
Published: November 2023

Abstract
The microwave region was the first part of the electromagnetic spectrum where essentially monochromatic radiation sources were used for molecular spectroscopy. This field was opened in the years around 1950 after the development of radar techniques in the second world war. Thus it became possible to measure the frequencies of rotational transitions in gaseous substances with great precision. A typical wavelength would be 1 cm, corresponding to a frequency of 30 000 MHz. At a typical gas pressure of a few Pa the lines are quite narrow and a transition frequency can easily be measured within 0.1 MHz (Fig. 3.1). Nowadays the frequency range which is available has been considerably extended. Millimeter wave spectra can be obtained relatively easily, and laser techniques have made many infrared measurements nearly as accurate as microwave ones. Still, as far as our interest in structure determinations is concerned, the interpretation of the results uses the same methods. We shall see that, unfortunately, much of the accuracy is lost when one tries to extract structural information from the observed transition frequencies.
Quantum mechanical determination of static and dynamic structure
Authors: Boggs James E 
Published: November 2023

Abstract
Recent years have witnessed an explosive proliferation in the use of all kinds of quantum chemical methods to evaluate molecular structures and vibrational dynamics. Semiempirical procedures have made major contributions in areas such as understanding the mechanisms of drug-substrate interactions, interpretation of organic mechanisms by study of reaction pathways and transition states, and in other applications where relatively rapid computation of molecular properties at a medium level of accuracy provides the needed information. However, this book is directed toward the experimental and theoretical methods that can provide structural information at the highest levels of accuracy and reliability so only ab initio theoretical methods or such methods with the computed parameters modified by minor empirical corrections are considered here. Accuracy in bond lengths to a few thousandths of an angstrom and in bond angles to a few tenths of a degree may be taken as an appropriate goal.