bluuebunny/crossref_metadata_2025 huggingface dataset:
The Woodward–Hoffmann rules and molecular orbitals
Authors: Ian Fleming
Published: September 2023

This chapter highlights the characteristic feature of all pericyclic reactions, which is the concertedness of bond-making and bond-breaking, and the absence of any intermediates. The chapter shows how organic chemists have proven that pericyclic reactions are concerted, particularly in the case of the Diels–Alder reaction. It also cites a number of powerful rules related to pericyclic reactions, including their basis in the conservation of symmetry of the molecular orbitals. The chapter explains the Arrhenius parameters for Diels–Alder reactions, which show that there is an exceptionally high negative entropy of activation with a low enthalpy of activation reflecting the exothermic nature of the reaction. It describes the compact transition structure that is in agreement with the negative volumes of activation which can be measured by carrying out the reaction under pressure.
Reactions of Alcohols, Ethers, Thiols, Sulfides, and Amines
Authors: Okuyama Tadashi , Maskill Howard
Published: September 2023

This chapter examines the principal methods of preparation of alcohols. It emphasizes that the characteristic properties of alcohols originate in the hydroxy group. Protonation of the O in alcohols and ethers converts poor leaving groups, HO− and RO−, into good ones, H2O and ROH. The chapter then reveals that this enhancement of reactivity by protonation is another example of acid catalysis. The chapter also covers other examples such as acid-catalysed nucleophilic substitution and elimination reactions. In these reactions, R–OH2+ and R–O(H)R+ are comparable with haloalkanes. The chapter also explores the ring-opening reactions of epoxides (oxiranes). It then shifts to discuss the reactions of the sulfur analogues of alcohols (thiols, RSH) and of ethers (sulfides, RSR'), which may be regarded as derivatives of hydrogen sulfide, H2S. It concludes by explaining the reactions of amines.
Organic Compounds: their Functional Groups, Intermolecular Interactions, and Physical Properties
Authors: Okuyama Tadashi , Maskill Howard
Published: September 2023

This chapter highlights that a molecule of an organic compound generally consists of what we call a functional group and a hydrocarbon residue. It notes that the distinctive properties of the compound are principally due to the functional group. The functional group consists of a few atoms bonded together and they react as a unit. Consequently, organic compounds are classified and named according to their functional groups. The chapter identifies the principal classes of organic compounds covered in this book and looks at how to name them. It assesses how some properties of a compound can only be understood in terms of large assemblies of molecules and the physical interactions between them (as opposed to properties of individual isolated molecules). The chapter also studies the elements of organic nomenclature, and further elaborates on the intermolecular interactions and physical properties of organic compounds.
Acids and Bases
Authors: Okuyama Tadashi , Maskill Howard
Published: September 2023

This chapter begins by outlining definitions of acids and bases based on Johannes N. Brønsted and Gilbert N. Lewis. Substances that taste sour have long been known as acids. Bases, on the other hand, are compounds which counteract or neutralize acids. The chapter then reviews the dissociation of a Brønsted acid in aqueous solution. It also presents the two important properties of buffer solutions. First, they allow us to prepare an aqueous solution of a desired pH using a weak acid and its conjugate base (a salt of the acid). The second important property of a buffer solution is that its pH will remain approximately constant if relatively small amounts of a further acid or base are added. Next, the chapter focuses on the factors which affect acid and base strengths. It also analyzes the basicity of organic compounds and the solvent effects on acid-base reactions.
Nucleophilic Substitution Reactions of Haloalkanes and Related Compounds
Authors: Okusecyama Tadashi , Maskill Howard
Published: September 2023

This chapter covers the substitution reactions of haloalkanes and related compounds under nucleophilic/basic conditions. It emphasizes that haloalkanes and related compounds containing a single bond from a saturated (sp3) carbon to a heteroatom can be represented generically as RY, where R is alkyl and Y is a halogen. The chapter then highlights the two most characteristic reactions of RY (substitution and elimination) under nucleophilic/basic conditions, both involve heterolysis of the bond from the electrophilic carbon to the heteroatom and departure of the nucleofuge. In substitutions, the nucleofuge is replaced by a nucleophile at the α C. However, as the chapter reveals, another substitution mechanism (SN1) is also possible depending upon the structure of RY and the reaction conditions. The chapter discusses both mechanisms, and explores the relationships between them. Next, the chapter analyzes the stereochemistry of substitution at saturated carbon, and the solvent effects upon substitution reactions.
Pericyclic Reactions: Cycloadditions, Electrocyclic Reactions, and Sigmatropic Rearrangements
Authors: Okuyama Tadashi , Maskill Howard
Published: September 2023

This chapter covers pericyclic reactions and their its types. In these so-called pericyclic reactions, all the bond forming and bond breaking occurs together with a nonpolar, concerted cyclic redistribution of valence electrons via aromatic transition structures. The chapter then presents and examines the three main groups of pericyclic reactions: cycloadditions, electrocyclic reactions, and sigmatropic rearrangements: the last two are both isomerization reactions. It then examines the Diels-Alder reactions and 1,3-dipolar cycloadditions, and reviews other cycloadditions and related reactions. Next, the chapter notes that pericyclic reactions are little influenced by changes in the nature of the solvent and they are not generally subject to catalysis. It then analyzes the molecular orbital considerations of pericyclic reactions.
Rearrangement Reactions involving Polar Molecules and Ions
Authors: Okuyama Tadashi , Maskill Howard
Published: September 2023

This chapter focuses on the [1,2] sigmatropic rearrangements. It shows how 1,2-shifts in carbenium ion intermediates in solvolytic reactions, for example, can be considered as [1,2] sigmatropic rearrangements, and (consequently) related to concerted sigmatropic rearrangements of nonpolar compounds. The MO description of these simple 1,2-shifts in carbenium ions can be extended to describe the rearrangement steps in more complicated multistep heterolytic reactions. The chapter also details the catalysed rearrangement of carbonyl compounds involving 1,2-shifts, then investigates the 1,2-shifts from carbon to oxygen and nitrogen. Finally, the chapter covers the stepwise rearrangements via cyclic intermediates formed by neighbouring group participation. It also looks at the rearrangements involving carbenes and nitrenes or their precursors.
Chemistry of Biomolecules
Authors: Okuyama Tadashi , Maskill Howard
Published: September 2023

This chapter addresses some of the major constituents of our body: carbohydrates, nucleic acids, proteins, and lipids, and related compounds. It emphasizes that although structures of many biomolecules may be complicated, their chemistry is not especially difficult. The chapter notes that their reactions are governed by the principles of the chemistry of simple organic compounds. The chapter also introduces the kinds of compounds which play major roles in living systems, and identifies the molecular features which allow them to function in their biological roles. Finally, the chapter looks at fats and oils, and phospholipids. It then considers the nature of terpenes, steroids, and eicosanoids.
Health
Authors: Hosey Geoff , Melfi Vicky , Pankhurst Sheila
Published: September 2023

This chapter focuses on the health of zoo animals. It discusses guidelines and legislation regarding the health of zoo animals, by referencing legislation in the UK and the European Union, such as the Balai Directive, European Endangered Species Programmes, and Species Survival Plans. Additionally, the chapter highlights the role of zoo staff in caring for the health of animals. It also talks about preventive medicine and lists its different methods: quarantine, health examination, vaccination, hygiene, pest control, parasite control, foot care, and enclosure management. The chapter then mentions diseases of concern for zoo animals alongside possible treatments for diseases such as rabies, salmonellosis, and tuberculosis. It explains that diseases can spread by contact with conspecifics, free-ranging species or pests.
People in zoos
Authors: Hosey Geoff , Melfi Vicky , Pankhurst Sheila
Published: September 2023

This chapter focuses on the impact and influence of people in zoos. It presents zoos as major attractions with reference to statistics on zoo visitors across the world. It also mentions the aims of zoos, which revolve around raising awareness and educating the public in subjects such as conservation and animals. The chapter then notes formal and informal ways of educating the public which include as the use of signs and keeper talks. Additionally, the chapter highlights the impact of zoo visitors on animals. Keepers are mostly perceived by animals differently than the visiting public. The chapter underlines the importance of training animals to adapt to people, referencing positive reinforcement training.
We hope you enjoyed your visit
Authors: Hosey Geoff , Melfi Vicky , Pankhurst Sheila
Published: September 2023

This chapter concludes the book. The evidence-based approach to zoo science extends beyond providing a basis for animal management and other activities. The chapter introduces possible careers in zoos such as zookeeper, zoo veterinarian, zoo veterinary nurse, assistant, and technician. It also presents the challenges for the future of zoos such as breeding, culling, and welfares. Additionally, the chapter explains how zoos will increasingly have to justify their decisions to cull surplus animals. It states that zoos need to understand that their duties of today are more than their commitment to conservation and education. Next, the chapter mentions how the process of data collection will continue to develop, especially for captive breeding of endangered species.
Structure and activities of prokaryotic cells
Authors: Wang Qiuyu , Smith Chris , Davis Emma
Published: September 2023

This chapter states that bacterial and archaeal cells have tough cell walls, although the bacteria Mycoplasma and archaea Thermoplasma do not. It discusses protection against osmotic lysis and mechanical damage and talks about the conferment of the shape to the cell as a function of the cell wall. It also describes bacterial and archaeal cytoplasm as protein-rich and gel-like, noting that large areas appear granular in the electron microscope due to the presence of ribosomes. The chapter illustrates the position of the DNA inside the nucleoid and notes that this is maintained by a series of fibres associated with the bacterial chromosome. It covers the cytoplasm of prokaryotes and some yeasts, which are eukaryotes and contain extrachromosomal DNA structures called plasmids.
The nucleus
Authors: Wang Qiuyu , Smith Chris , Davis Emma
Published: September 2023

This chapter describes the size and shape of the nucleus which is maintained by a nuclear skeleton composed of fibrous proteins, which also provides an organizing frame to which the chromatin fibres are attached. The chapter explains replication as the process by which cellular DNA is copied to form two complete daughter strands of DNA, which occurs during interphase when the cell produces two copies of its chromosomal DNA before cell division begins. The chapter also talks about eukaryotic promoters that can be upstream or downstream of the transcription start, and vary between the various RNA polymerase types. The chapter shows how eukaryotic premRNA is formed by RNA polymerase II and notes that it requires modification following its transcription. It examines nucleoli as prominent structures that are present in nuclei.
Viruses
Authors: Wang Qiuyu , Smith Chris , Davis Emma
Published: September 2023

This chapter describes viruses as infectious, obligate, intracellular parasites that infect organisms from all three domains: bacteria, archaea, and eucarya. It talks about Dmitri Ivanovsky, who showed that the causative agent of tobacco mosaic disease was not retained by filters that removed bacterial cells from liquid suspensions in 1892, surmising it as a new type of infectious agent he called contagium vivum fluidum. The chapter also covers the size range of virus particles or virions from approximately 30 to 300 nm in length/diameter, which makes them considerably smaller than cells. The chapter highlights three basic types of virus particles according to symmetry: helical symmetry, cuboid symmetry, and complex symmetry. It considers virus particles outside host cells as biologically inert as they can only replicate within host cells.
Instrumental Analysis (International Edition)
Authors: Granger Robert M. , Yochum Hank M. , Granger Jill N. , Sienerth Karl D. , Granger Robert M. , Yochum Hank M. , Granger Jill N. , Sienerth Karl D.
Published: September 2023

Instrumental Analysis XE
begins by presenting the analyst's toolbox. The next chapter covers quantum mechanics and spectroscopy. Other topics include optics, instrumental electronics, signals and noise and signal processing, molecular ultraviolet and visible spectroscopy, and atomic absorption spectroscopy. The text then goes on to cover luminescence spectroscopy, atomic emission spectroscopy, infrared spectroscopy, and raman spectroscopy. There are also chapters on mass spectroscopy, nuclear magnetic resonance spectroscopy, and liquid chromatography. Next, there are chapters on gas chromatography and electrophoresis. Finally, the text looks at potentiometry and probes and statistical data analysis.
Signals and Noise
Authors: Granger Robert M. , Yochum Hank M. , Granger Jill N. , Sienerth Karl D. , Granger Robert M. , Yochum Hank M. , Granger Jill N. , Sienerth Karl D.
Published: September 2023

This chapter talks about advanced techniques of signal-to-noise improvement which detect single molecules and produce visual images, which shows the result of fluorescence imaging of a single DNA molecule. It characterizes signals and noise in experimental data in order to find signals by altering the measurement approach, and to increase signals by working with data mathematically. It also analyzes the relationship between the detector response associated with the particular property of the analyte of interest and the detector response associated with other factors not related to the particular property of the analyte. The chapter points out that a signal might have components that are both direct current (DC) and alternating current (AC). It addresses the question on what constitutes the signal and what constitutes the noise.
Mass Spectrometry
Authors: Granger Robert M. , Yochum Hank M. , Granger Jill N. , Sienerth Karl D. , Granger Robert M. , Yochum Hank M. , Granger Jill N. , Sienerth Karl D.
Published: September 2023

This chapter discusses the mass spectrum, which is the output of a mass spectrometer (MS) that yields information directly related to the structure of analyte molecules. It details how an MS makes inferences about bond strengths and the existence of specific functional groups within the molecule. It considers MS as one of the most important tools available for molecular identification, often being used as a molecular fingerprinting technique to identify the unknown components of samples. The chapter details how the analyte in MS is ionized and the mass-to-charge ratio of the analyte is measured. It reviews the term spectrum, which refers to the range of mass-to-charge ratios of ions generated by the instrument from the analyte in the sample and electromagnetic radiation that does not play a role in generating the signal.
An Introduction to Nuclear Magnetic Resonance Spectroscopy
Authors: Granger Robert M. , Yochum Hank M. , Granger Jill N. , Sienerth Karl D. , Granger Robert M. , Yochum Hank M. , Granger Jill N. , Sienerth Karl D.
Published: September 2023

This chapter talks about nuclear magnetic resonance (NMR), which is the primary instrumental method for determining molecular structure. It introduces the underlying principles of how the NMR spectrometer functions and how a signal is obtained and processed, reintroducing spectral interpretation. It also cites a key advantage of NMR analysis, which is the fact that the results provide structural information about how the individual pieces of the molecule are connected. The chapter emphasizes how NMR can provide the final interpretation to identify an unknown substance or to provide evidence that the compound under study is the analyte of interest. It highlights NMR transitions which directly probe the chemical environment of each NMR active nucleus in a molecule.
Phylogenetic Systematics and the Origins of Amphibians and Reptiles
Authors: Harvey Pough F. , Andrews Robin M. , Crump Martha L. , Savitzky Alan H. , Wells Kentwood D. , Brandley Matthew C.
Published: September 2023

This chapter discusses the phylogenetic systematics and the origins of amphibians and reptiles. It begins by looking at the principles of phylogenetics and taxonomy. The chapter then traces the origins of terrestriality from aquatic ancestors and the subsequent diversification of amphibian and reptile groups, many of which are extinct and have left no descendants living today. There are three hypotheses for the origin of extant amphibians: the temnospondyl hypothesis, the lepospondyl hypothesis, and the diphyly hypothesis. The chapter also considers the relationships among extant lissamphibian lineages, the characteristics and origin of the amniotes, lepidosauria, and archosauria, and the debated origins of turtles.
Reproduction and Life Histories of Amphibians
Authors: Harvey Pough F. , Andrews Robin M. , Crump Martha L. , Savitzky Alan H. , Wells Kentwood D. , Brandley Matthew C.
Published: September 2023

This chapter describes the reproduction and life histories of amphibians, including the behaviours associated with mating, how eggs are fertilized, sex determination, development and metamorphosis of larvae, and parental care. Reproduction is by far the most conspicuous feature of amphibian biology, and most casual observers seldom encounter amphibians outside of the breeding season. Many amphibians have external fertilization, whereas others fertilize their eggs inside the body of the female. Some of the most successful amphibians, including most plethodontid salamanders and Neotropical frogs in the families Eleutherodactylidae and Craugastoridae, have abandoned aquatic reproduction altogether and lay terrestrial eggs that undergo direct development into miniature adults. Some amphibians retain their eggs inside the reproductive tract of the female and give birth to live young; others provide elaborate forms of parental care, including transporting and feeding their offspring.
Taxonomic Evidence: Structural and Biochemical Characters
Authors: Judd Walter S. , Campbell Christopher S. , Kellogg Elizabeth A. , Stevens Peter F. , Donoghue Michael J.
Published: September 2023

The chapter focuses on taxonomic evidence consisting of the characters used in phylogenetic analyses. Plant classifications are based on this evidence, including characters used in describing patterns of variation at or below the species level. The chapter shows how taxonomic evidence can be gathered from a wide variety of sources, from all parts of a plant, and during all stages of a plant's development. It also summarizes the use of characters from morphology, anatomy, embryology, chromosomes, palynology, secondary metabolites, and proteins. The chapter also considers nucleic acids, namely DNA and RNA, as these are an increasingly important source of taxonomic characterization in plant taxonomy and the rapidly developing field of molecular systematics. The chapter also discusses morphological characters, which are used for practical plant identification and hypothesizing phylogenetic relationships.
An Overview of Green Plant Phylogeny
Authors: Judd Walter S. , Campbell Christopher S. , Kellogg Elizabeth A. , Stevens Peter F. , Donoghue Michael J.
Published: September 2023

This chapter traces the origin and evolution of several separately derived plant lineages, thereby putting the green plant lineage into a broad phylogenetic perspective. It focuses on the evolution of green plants and several critical transitions, including the origin of the land plants, vascular plants, seed plants, and flowering plants. It also chronicles the evolutionary events leading up to the mosses, the horsetails, or any other group leading to angiosperms. The chapter depicts phylogenetic relationships among the major branches of the entire tree of life based on recent analyses and explains the broad phylogenetic distribution of photosynthetic organisms. It refers to chloroplasts found in eukaryotes that are endosymbiotic organelles and derived ultimately from a cyanobacterial ancestor.
Innovations in Agriculture
Authors: Davies H. Maelor
Published: September 2023

This chapter explores how farm technologies are developed and how they reach farmers. Farmers obtain seeds in one or more of four different ways. They may obtain seed freely through sharing with other farmers; purchase from seed companies with no restrictions on their future propagation; purchase seed of varieties suitable for only one crop-production cycle; and/or purchase with formal agreement that limits use to a single crop-production cycle. The ability to patent plant varieties combined with the development of advanced plant genetics led to considerable consolidation of the seed-supply industry. The chapter then looks at how domination of the seed-supply for the major crops by just a few large companies has led to concerns about limited genetic diversity among the major crops, and debate about who actually owns plant varieties. It considers how agricultural technologies and practices are subject to oversight and regulation.
Soil Ecosystems,Plant Nutrition, and Nutrient Cycling
Authors: Engstrom Eric M.
Published: September 2023

This chapter studies soil ecosystems, plant nutrition, and nutrient cycling. Soils are complex ecosystems where changes in one soil variable are likely to affect multiple other variables, often in ways that are difficult to predict accurately. Chemical elements cycle within the ecosystem. Chemical transformations occur continuously, fueled by biological and physical processes. Agricultural systems are inherently different from natural ecosystems in that soil nutrients are regularly removed from agricultural systems and must be replaced. In addition, agricultural ecosystems, which often encompass only one crop, have almost no aboveground biodiversity. The chapter then looks at the roles of soil nutrients, soil organic matter, and plant roots. It also considers plant nutrients such as nitrogen and phosphorus, before discussing mycorrhizae.
Biotic Challenges: Weeds
Authors: Tranel Patrick J.
Published: September 2023

This chapter reviews weed management — an enormous problem in all agricultural systems — and highlights the danger of relying entirely on crops that are genetically engineered to resist weeds. Weeds compete with crops for nutrients, water, sunlight, and space, and therefore diminish crop yields. Therefore, farmers have a number of different options to manage their weed populations. Many farmers use chemical weed control as the primary option to control weeds; herbicides target plant-specific biochemical processes. However, overreliance on herbicides results in the emergence of herbicide-resistant weeds. The chapter then considers how herbicide-tolerant crops can be obtained by genetic engineering and can further simplify weed management. It also looks at how sustainable weed management systems require the integration of a diversity of weed control tactics.
Food Safety
Authors: Tribe David
Published: September 2023

This chapter explores food safety. All novel foods (crops or processed foods) may carry toxicity hazards, and governments have set up regulatory agencies for the purpose of examining these hazards. The safety of genetically engineered (GE) crops has been examined by many scientists and health organizations and they have an excellent safety record. Safety evaluation begins with analysing the components present in a GE crop and comparing the levels with a non-GE variety of the same species that has a history of safe use. Molecular methods make it possible to examine the chromosomal site where DNA is inserted, and the presence of novel proteins and metabolites. The chapter then looks at how gene editing allows scientists to create novel varieties that do not contain foreign DNA.
Conservation Biology
Authors: Cardinale Bradley J. , Primack Richard B. , Murdoch James D.
Published: September 2023

Conservation Biology is composed of four parts. Part I presents the foundations of conservation biology which includes the rise of this topic. It looks also at global patterns and diversity. Part II is about the importance of biodiversity and includes an examination of ecological economics. The next part is about threats to biodiversity and includes extinction, habitat loss, fragmentation, degradation, overexploitation, alien species, and climate change. The final part looks at approaches to conservation including species-level conservation, community and ecosystem conservation, landscape-scale conservation, ex situ conservation, and conservation and sustainable development.
The State of Our Planet
Authors: Cardinale Bradley J. , Primack Richard B. , Murdoch James D.
Published: September 2023

This chapter provides an overview of the current state of biology on our planet. It establishes some basic facts about the forms of environmental change that are occurring across the globe as a result of human domination of the planet and the subsequent impact that these changes are having on biodiversity. The chapter begins with the state of the human species, emphasizing gains that have allowed our species to be successful, while also highlighting the social inequalities that prevent many from having a good quality of life. It then reviews the state of our global environment, and discusses how human gains for some have come at a cost to the environment. Finally, the chapter looks at the state of biodiversity, including biodiversity losses that are occurring as a result of environmental change.
Biodiversity and Ecosystem Services
Authors: Cardinale Bradley J. , Primack Richard B. , Murdoch James D.
Published: September 2023

This chapter focuses on biodiversity and ecosystem services. Ecosystem services can be defined as ‘nature's contributions to people’. They represent the plethora of benefits that humans receive from both natural and managed ecosystems, including things like the production of consumable goods, non-consumable services, and cultural services. We could just as well define ecosystem services as the collection of biological processes that are required to sustain human life and provide a good standard of living on Earth. Despite their indisputable importance, many people do not know about ecosystem services; nor do they understand or appreciate their value. The chapter then looks at the history and types of ecosystem services. It also considers the biotic control of ecosystem services before examining ecosystem markets and payments for ecosystem services.
Ecological Economics
Authors: Cardinale Bradley J. , Primack Richard B. , Murdoch James D.
Published: September 2023

This chapter assesses ecological economics. Economics is the social science discipline that seeks to understand the decisions people make about the use of scarce resources given their preferences and values. Different subfields in economics address different resource allocation problems involving the supply, demand, and allocation of goods and services. The subfield of ecological economics addresses the supply, demand, and allocation of goods and services that are supplied to society by Earth's natural ecosystems. Ecological economics assumes that the human economy, which is based on man-made capital, is part of a larger economic system that also includes the natural capital of Earth's ecosystems. The chapter then considers the different decision-making analyses, the total economic value (TEV) framework, and the methods of valuing ecosystem services.
Climate Change
Authors: Cardinale Bradley J. , Primack Richard B. , Murdoch James D.
Published: September 2023

This chapter reviews how modern anthropogenic climate change impacts biodiversity and how conservation biologists can mitigate these effects. Anthropogenic climate change is a general term that refers to a suite of abiotic variables that are changing simultaneously across the planet as a result of human activities. Each year, thousands of scientific papers are published that advance our understanding of how the averages, ranges, variability, frequency, predictability, and seasonality of the abiotic variables that regulate Earth's climate are changing across the globe. The main governing body charged with summarizing this literature is the Intergovernmental Panel on Climate Change (IPCC). The chapter then considers the predicted impacts of climate change on biodiversity, the impacts that have been documented to date, and the management strategies available to practitioners to mitigate the impacts of climate change.
Community and Ecosystem Conservation
Authors: Cardinale Bradley J. , Primack Richard B. , Murdoch James D.
Published: September 2023

This chapter examines community and ecosystem conservation. The primary tool used for conservation of whole communities and ecosystems is the protected area. A protected area is a clearly defined geographical space that is recognized, dedicated, and managed to achieve long-term conservation of nature and its associated ecosystem services. The concept of protected areas has been around for centuries, but the establishment of protected areas for the purpose of conserving whole ecosystems and their biodiversity is a relatively new concept that began with establishment of national parks. The chapter begins by outlining the classification and global status of protected areas. It then reviews the approaches used to select protected areas, as well as the effectiveness of protected areas for conservation.
Water and Plant Cells
Authors: Taiz Lincoln , Zeiger Eduardo , Møller Ian Max , Murphy Angus
Published: September 2023

This chapter discusses how water plays a crucial role in the life of the plant. Photosynthesis requires that plants draw carbon dioxide from the atmosphere, and at the same time exposes them to water loss and the threat of dehydration. To prevent leaf desiccation, water must be absorbed by the roots and transported through the plant body. Even slight imbalances between the uptake and transport of water and the loss of water to the atmosphere can cause water deficits and severe malfunctioning of many cellular processes. The chapter then considers how water moves into and out of plant cells, emphasizing the molecular properties of water and the physical forces that influence water movement at the cell level. It looks at how cell walls allow plant cells to build up large internal hydrostatic pressures, called turgor pressure, and differentiates between diffusion and osmosis.
Solute Transport
Authors: Taiz Lincoln , Zeiger Eduardo , Møller Ian Max , Murphy Angus
Published: September 2023

This chapter assesses the physical and chemical principles that govern the movements of molecules in solution. It shows how these principles apply to membranes and biological systems. The chapter then discusses the molecular mechanisms of transport in living cells and the great variety of membrane transport proteins that are responsible for the particular transport properties of plant cells. It also describes a specialized cell type, the guard cells regulating stomatal opening, where transmembrane ion transport play a vital role. Finally, the chapter examines the pathways that ions take when they enter the root as well as the mechanism of xylem loading, the process whereby ions are released into the tracheary elements of the stele. Because transported substances, including carbohydrates, amino acids, and metals such as iron and zinc, are vital for human nutrition, understanding and manipulating solute transport in plants can contribute solutions to sustainable food production.
Photosynthesis The Carbon Reactions
Authors: Taiz Lincoln , Zeiger Eduardo , Møller Ian Max , Murphy Angus
Published: September 2023

This chapter begins by analysing the metabolic cycle that incorporates atmospheric CO2 into organic compounds appropriate for life: the Calvin–Benson cycle. It then considers how the unavoidable phenomenon of photorespiration—a consequence of a side reaction with molecular oxygen—releases part of the assimilated CO2. Because photorespiration decreases the efficiency of photosynthetic CO2 assimilation, the chapter also examines biochemical mechanisms for mitigating the loss of CO2: CO2 pumps, C4 metabolism, and crassulacean acid metabolism. Finally, the chapter briefly looks at the formation of the two major products of the photosynthetic CO2 fixation. These are starch, the reserve polysaccharide that accumulates transiently in chloroplasts, and sucrose, the disaccharide that is exported from leaves to developing and storage organs of the plant.
Signals and Signal Transduction
Authors: Taiz Lincoln , Zeiger Eduardo , Møller Ian Max , Murphy Angus
Published: September 2023

This chapter begins by providing a brief overview of the types of external cues that direct plant growth. In general, an environmental input that initiates one or more plant responses is referred to as a signal, and the physical component that biochemically responds to that signal is designated a receptor. Receptors are either proteins or, in the case of light receptors, pigments associated with proteins. Once receptors sense their specific signal, they must transduce the signal in order to amplify the signal and trigger the cellular response. The chapter then discusses how plants employ signal transduction pathways to regulate physiological responses. It examines how individual stimulus-response cascades are often integrated with other signaling pathways, termed cross-regulation, to shape plant responses to their environment in time and space. The chapter also considers phytohormone metabolism and homeostasis, as well as hormonal signaling pathways.
Abiotic Stress
Authors: Taiz Lincoln , Zeiger Eduardo , Møller Ian Max , Murphy Angus
Published: September 2023

This chapter explores how plants adapt and respond to abiotic stresses in the environment. Like all living organisms, plants are complex biological systems comprising thousands of different genes, proteins, regulatory molecules, signaling agents, and chemical compounds that form hundreds of interlinked pathways and networks. When exposed to unfavourable environmental conditions, this complex interactive system adjusts homeostatically to minimize the negative impacts of stress and maintain metabolic equilibrium. The chapter begins by distinguishing between adaptation and acclimation in relation to abiotic stress. It then describes the various abiotic factors in the environment that can negatively affect plant growth and development. Finally, the chapter considers the specific metabolic, physiological, and anatomical changes that result from signaling pathways and that enable plants to adapt or acclimate to abiotic stress.
Ecosystem Processes
Authors: Gurevitch Jessica , Scheiner Samuel M. , Fox Gordon A.
Published: September 2023

This chapter turns to the nature of the ecosystem and its processes. It emphasizes that ecosystems are composed of all living organisms, the remains or discarded parts of organisms, and the nonliving environment with which organisms interact and which surrounds and pervades them. The chapter seeks to understand what regulates the pools (quantities stored) and fluxes (flows) of materials and energy in the various abiotic and biotic components of ecosystems. Quantifying these pathways, the size and nature of the pools of materials, the rate at which fluxes of materials and energy are transferred, and the factors controlling these pools and fluxes are the focus of ecosystem ecology. While a single ecosystem is generally of limited size, typically corresponding to a local community, the processes of material and energy flow can extend from that local community to the entire globe. The chapter concludes by investigating how those processes link across scales.
Local Abundance, Diversity, and Rarity
Authors: Gurevitch Jessica , Scheiner Samuel M. , Fox Gordon A.
Published: September 2023

This chapter addresses a series of questions that raise fundamental issues in ecology and also have major implications for applied ecology and conservation. It seeks to answer questions like: what determines the relative abundances of the individuals in a community ever since ecology was a scientific discipline? What determines how many species can coexist in a community? The chapter aims to understand how species interact, and whether that has anything to do with their abundances. It also examines why some species are rare, others common, and still others invasive, in order to understand the fundamental properties of ecological communities, and for practical reasons. The chapter focuses mainly on the abundances of the individuals in a species as well as the number of species at the scale of communities. It concludes by examining interaction between local and regional processes from a local perspective.
Climate, Plants, and Climate Change
Authors: Gurevitch Jessica , Scheiner Samuel M. , Fox Gordon A.
Published: September 2023

This chapter concentrates on the underlying climatic factors that control not just vegetation patterns but all life on Earth. It looks at the physical factors determining seasons, intermediate-scale cycles of climate change lasting years to decades, and much longer-term cycles. Any attempt to determine the causes of large-scale vegetation patterns must start with climate. Climate refers to the long-term averages and statistical distribution of the weather at any scale from local to global, while weather refers to the immediate or short-term conditions at local scales. The chapter then describes the patterns of climatic variation around the world (with special attention to North America), then explains the mechanisms responsible for those patterns. It also considers the role of plants as they respond to and influence climate, then discusses how humans are changing Earth's climate, as well as some of the impacts of these changes.
Paleoecology
Authors: Gurevitch Jessica , Scheiner Samuel M. , Fox Gordon A.
Published: September 2023

This chapter focuses on very long-term patterns over time and over large spatial extents. It considers some of these long-term changes in plants and plant communities, the scientific methods used for understanding them, and some of their implications. The chapter then highlights the field of paleoecology, which is the study of historical ecology. Our understanding of the very distant past is especially tenuous because of a dearth of fossils from those times and because many ancient species have no modern analogues. Our knowledge of the past, however, is increasing rapidly. The chapter first surveys several geological eras and periods, especially those that represent significant times of change for plant communities. It then looks in detail at the past 20,000 years. Because of the amount of detail involved, the chapter focuses on North America. The history of this recent period is now well known and provides special insight into current plant communities and biomes.
An international survey-based assessment of minimally invasive mitral valve surgery
Authors: Fatehi Hassanabad Ali , Imran Hamid Umar , Sardari Nia Peyman
Published: September 2023

OBJECTIVES

Minimally invasive mitral valve surgery (MIMVS) has been shown to be safe and feasible however its adoption has lagged globally. The international consortium is lacking a set of guidelines that are specific to MIMVS. The aim of this study was to capture the practices of MIMVS in different centres.

METHODS

A survey was constructed containing 52 multiple-choice and open-ended questions about various aspects of MIMVS. The survey was sent to centres that routinely and frequently perform MIMVS. All surgeons provided informed consent for participating in the survey and publication of data.

RESULTS

The survey was sent to 75 known surgeons from whom 32 (42%) completed the survey. All survey responders performed >25 MIMVS cases annually. Twenty (68%) of the surgeons thought that simulation training, MIMVS fellowship and proctorship are all essential prior to commencing an MIMVS program. Eleven (34%) of the surgeons stated that 50–100 MIMVS cases are required to overcome the learning curve, followed by 6 (18%) who said 21–30 cases should suffice. Eighteen (62%) of the surgeons had adopted a fully endoscopic approach for their MIMVS, followed by 15 (51%) surgeons who had performed cases via endoscopic-assisted strategies, 5 (17%) surgeons had conducted the operation under direct visualization and 6 (20%) surgeons had used a robot for their MIMVS.

CONCLUSIONS

The study highlights a marked variability on training and approach to MIMVS. Consensus guidelines should be established to allow standardization of MIMVS.
Masculinity Crisis or Intergenerational Perceptual Biases? Explicating Public Acquiescence to the Media Regulation on Effeminate Masculinity
Authors: Yang Xinying , Qiu Hongfeng
Published: September 2023

By drawing on the perspective of the third-person effect (TPE), this study explains Chinese men’s general acquiescence to the nation’s recent media regulation on effeminate masculinity. Data were collected among Chinese male netizens through an online cross-sectional survey (N = 735) and processed using a paired samples t-test, regression analysis, and mediation test. The statistical results demonstrate that public silence is not based on their perception of a masculinity crisis but rather a generation gap in self-other perceptual biases that conceive the younger generation as more susceptible to the influence of effeminate male media figures. Furthermore, the study found that media exposure, perceived desirability, critical media literacy, and gender ideology significantly predicted respondents’ related perceptions through the mediation of social distance. While frequent media exposure and positive media portrayals have demonstrated a potential for reducing prejudice against nonconventional gender performances, the recent official restriction on effeminate masculinity may perpetuate this prejudice. Overall, this study enriches the literature on the TPE by comparing intergenerational differences in perceptual biases regarding the social implications of media portrayals of effeminate masculinity.
External Validation of the Discriminative Validity of the ReSVinet Score and Development of Simplified ReSVinet Scores in Secondary Care
Authors: Sheikh Zakariya , Potter Ellie , Li You , Drysdale Simon B , Wildenbeest Joanne G , Robinson Hannah , McGinley Joseph , Lin Gu-Lung , Öner Deniz , Aerssens Jeroen , Justicia-Grande Antonio José , Martinón-Torres Federico , Pollard Andrew J , Bont Louis , Nair Harish
Published: September 2023

Background

There is no consensus on how to best quantify disease severity in infants with respiratory syncytial virus (RSV) and/or bronchiolitis; this lack of a sufficiently validated score complicates the provision of clinical care and, the evaluation of trials of therapeutics and vaccines. The ReSVinet score appears to be one of the most promising; however, it is too time consuming to be incorporated into routine clinical care. We aimed to develop and externally validate simplified versions of this score.

Methods

Data from a multinational (the Netherlands, Spain, and United Kingdom) multicenter case-control study of infants with RSV were used to develop simplified versions of the ReSVinet score by conducting a grid search to determine the best combination of equally weighted parameters to maximize for the discriminative ability (measured by area under the receiver operating characteristic curve [AUROC]) across a range of outcomes (hospitalization, intensive care unit admission, ventilation requirement). Subsequently discriminative validity of the score for a range of secondary care outcomes was externally validated by secondary analysis of datasets from Rwanda and Colombia.

Results

Three candidate simplified scores were identified using the development dataset; they were excellent (AUROC >0.9) at discriminating for a range of outcomes, and their performance was not significantly different from the original ReSVinet score despite having fewer parameters. In the external validation datasets, the simplified scores were moderate to excellent (AUROC, 0.7–1) across a range of outcomes. In all outcomes, except in a single dataset for predicting admission to the high-dependency unit, they performed at least as well as the original ReSVinet score.

Conclusions

The candidate simplified scores developed require further external validation in larger datasets, ideally from resource-limited settings before any recommendation regarding their use.
Levels of Angiopoietin 2 Are Predictive for Mortality in Patients Infected With Yellow Fever Virus
Authors: van de Weg Cornelia A M , Thomazella Mateus V , Marmorato Mariana P , Correia Carolina A , Dias Juliana Z C , Maestri Alvino , Zanella Luiz G F A B E , Cerqueira Natalia B , Félix Alvina C , Moreira Carlos H V , Buccheri Renata , Costa Priscilla R , Kallás Esper G
Published: September 2023

In 2018 there was a large yellow fever outbreak in São Paulo, Brazil, with a high fatality rate. Yellow fever virus can cause, among other symptoms, hemorrhage and disseminated intravascular coagulation, indicating a role for endothelial cells in disease pathogenesis. Here, we conducted a case-control study and measured markers related to endothelial damage in plasma and its association with mortality. We found that angiopoietin 2 is strongly associated with a fatal outcome and could serve as a predictive marker for mortality. This could be used to monitor severe cases and provide care to improve disease outcome.
Evaluating Japan’s defense cooperation agreements and their transformative potential: upgrading strategic partnerships with Australia and the UK
Authors: Baldauff Nanae , Heng Yee-Kuang
Published: September 2023

Japan’s defense cooperation agreements (DCAs) have been proliferating in recent years. Despite Japan’s harsh security environment, rather than expanding formal military alliances beyond its sole US ally, DCAs have emerged as a crucial instrument deployed by Japan to strengthen bilateral and minilateral defense relations with various partners. How do we make sense of Japan’s growing activism in forging DCAs? Yet, there does not currently exist a framework to systematically evaluate these DCAs, nor is there a detailed assessment of the utility of these DCAs in transforming Japan’s partnerships with like-minded states. This article proposes an analytical matrix derived from several key performance indicators and applies it to evaluate how Japan’s use of DCAs has transformed its defense relationships with two key strategic partners, Australia and the UK.