Alan Bowman and Andrew Wilson (eds)
- Published in print:
- 2009
- Published Online:
- September 2009
- ISBN:
- 9780199562596
- eISBN:
- 9780191721458
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199562596.001.0001
- Subject:
- Classical Studies, European History: BCE to 500CE
This book contains a number of chapters on the Roman economy which discuss methods of analysing the performance of the economy of the Mediterranean world under Roman imperial rule in the period c.100 ...
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This book contains a number of chapters on the Roman economy which discuss methods of analysing the performance of the economy of the Mediterranean world under Roman imperial rule in the period c.100 BC to AD 350 through quantification. It focuses on the methods and problems involved in identifying and analyzing the characteristics of economic integration, growth, and decline in this period. In particular, it attempts to suggest how a complex and diverse economic world can be better understood by using quantifiable and proxy data to measure these processes in different parts of the Mediterranean world. The data are drawn from both documentary and archaeological sources, and the book emphasizes the need to draw together different kinds of written and artefactual evidence and to describe the ways in which they complement each other. This approach is pursued in a series of analyses of approaches specific economic sectors: demography, urbanization and settlement patterns, the agrarian economy, patterns of trade and commerce, mining, metal supply, and coinage. The book offers a survey of the opportunities for advancing understanding of the economic and technological development of the Roman empire by using the tools and techniques of economic history and statistical analysis.Less
This book contains a number of chapters on the Roman economy which discuss methods of analysing the performance of the economy of the Mediterranean world under Roman imperial rule in the period c.100 BC to AD 350 through quantification. It focuses on the methods and problems involved in identifying and analyzing the characteristics of economic integration, growth, and decline in this period. In particular, it attempts to suggest how a complex and diverse economic world can be better understood by using quantifiable and proxy data to measure these processes in different parts of the Mediterranean world. The data are drawn from both documentary and archaeological sources, and the book emphasizes the need to draw together different kinds of written and artefactual evidence and to describe the ways in which they complement each other. This approach is pursued in a series of analyses of approaches specific economic sectors: demography, urbanization and settlement patterns, the agrarian economy, patterns of trade and commerce, mining, metal supply, and coinage. The book offers a survey of the opportunities for advancing understanding of the economic and technological development of the Roman empire by using the tools and techniques of economic history and statistical analysis.
V. F. Gantmakher
- Published in print:
- 2005
- Published Online:
- September 2007
- ISBN:
- 9780198567561
- eISBN:
- 9780191718267
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198567561.001.0001
- Subject:
- Physics, Condensed Matter Physics / Materials
This book contains modern concepts about the physics of electrons in solids. It is written using a minimum of mathematics, with the emphasis on various physical models aimed at stimulating creative ...
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This book contains modern concepts about the physics of electrons in solids. It is written using a minimum of mathematics, with the emphasis on various physical models aimed at stimulating creative thinking. The book aims to aid in the choice of the most efficient scheme of an experiment or the optimal algorithm of a calculation. Boltzmann and hopping types of conductivity are compared. The qualitative theory of weak localization is presented and its links with the true localization and metal-insulator transitions. Processes that determine the structure of impurity bands are revealed. The concepts introduced in this book are applied to descriptions of granular metals and quasicrystals, as well as the integer quantum Hall effect, emphasizing their universality.Less
This book contains modern concepts about the physics of electrons in solids. It is written using a minimum of mathematics, with the emphasis on various physical models aimed at stimulating creative thinking. The book aims to aid in the choice of the most efficient scheme of an experiment or the optimal algorithm of a calculation. Boltzmann and hopping types of conductivity are compared. The qualitative theory of weak localization is presented and its links with the true localization and metal-insulator transitions. Processes that determine the structure of impurity bands are revealed. The concepts introduced in this book are applied to descriptions of granular metals and quasicrystals, as well as the integer quantum Hall effect, emphasizing their universality.
Peter S. Wells
- Published in print:
- 2012
- Published Online:
- October 2017
- ISBN:
- 9780691143385
- eISBN:
- 9781400844777
- Item type:
- book
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691143385.001.0001
- Subject:
- Archaeology, Historical Archaeology
The peoples who inhabited Europe during the two millennia before the Roman conquests had established urban centers, large-scale production of goods such as pottery and iron tools, a money economy, ...
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The peoples who inhabited Europe during the two millennia before the Roman conquests had established urban centers, large-scale production of goods such as pottery and iron tools, a money economy, and elaborate rituals and ceremonies. Yet as this book argues, the visual world of these late prehistoric communities was profoundly different from those of ancient Rome's literate civilization and today's industrialized societies. Drawing on startling new research in neuroscience and cognitive psychology, the book reconstructs how the peoples of pre-Roman Europe saw the world and their place in it. It sheds new light on how they communicated their thoughts, feelings, and visual perceptions through the everyday tools they shaped, the pottery and metal ornaments they decorated, and the arrangements of objects they made in their ritual places—and how these forms and patterns in turn shaped their experience. The book offers a completely new approach to the study of Bronze Age and Iron Age Europe, and represents a major challenge to existing views about prehistoric cultures. It demonstrates why we cannot interpret the structures that Europe's pre-Roman inhabitants built in the landscape, the ways they arranged their settlements and burial sites, or the complex patterning of their art on the basis of what these things look like to us. Rather, we must view these objects and visual patterns as they were meant to be seen by the ancient peoples who fashioned them.Less
The peoples who inhabited Europe during the two millennia before the Roman conquests had established urban centers, large-scale production of goods such as pottery and iron tools, a money economy, and elaborate rituals and ceremonies. Yet as this book argues, the visual world of these late prehistoric communities was profoundly different from those of ancient Rome's literate civilization and today's industrialized societies. Drawing on startling new research in neuroscience and cognitive psychology, the book reconstructs how the peoples of pre-Roman Europe saw the world and their place in it. It sheds new light on how they communicated their thoughts, feelings, and visual perceptions through the everyday tools they shaped, the pottery and metal ornaments they decorated, and the arrangements of objects they made in their ritual places—and how these forms and patterns in turn shaped their experience. The book offers a completely new approach to the study of Bronze Age and Iron Age Europe, and represents a major challenge to existing views about prehistoric cultures. It demonstrates why we cannot interpret the structures that Europe's pre-Roman inhabitants built in the landscape, the ways they arranged their settlements and burial sites, or the complex patterning of their art on the basis of what these things look like to us. Rather, we must view these objects and visual patterns as they were meant to be seen by the ancient peoples who fashioned them.
R. E. Peierls
- Published in print:
- 2001
- Published Online:
- September 2007
- ISBN:
- 9780198507819
- eISBN:
- 9780191709913
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198507819.001.0001
- Subject:
- Physics, Condensed Matter Physics / Materials
This book develops the quantum theory of solids from the basic principles of quantum mechanics. The emphasis is on a single statement of the ideas underlying the various approximations that have to ...
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This book develops the quantum theory of solids from the basic principles of quantum mechanics. The emphasis is on a single statement of the ideas underlying the various approximations that have to be used in the study of this subject. Care is taken to separate sound arguments from conjecture. The treatment covers the electron theory of metals as well as the dynamics of crystals, including the author's work on the thermal conductivity of crystals.Less
This book develops the quantum theory of solids from the basic principles of quantum mechanics. The emphasis is on a single statement of the ideas underlying the various approximations that have to be used in the study of this subject. Care is taken to separate sound arguments from conjecture. The treatment covers the electron theory of metals as well as the dynamics of crystals, including the author's work on the thermal conductivity of crystals.
Jennifer S. Cavet, Robert D. Perry, Sascha Brunke, K. Heran Darwin, Carol A. Fierke, James A. Imlay, Michael E. P. Murphy, Anthony B. Schryvers, Dennis J. Thiele, and Jeffrey N. Weiser
- Published in print:
- 2015
- Published Online:
- May 2016
- ISBN:
- 9780262029193
- eISBN:
- 9780262327619
- Item type:
- chapter
- Publisher:
- The MIT Press
- DOI:
- 10.7551/mitpress/9780262029193.003.0007
- Subject:
- Public Health and Epidemiology, Public Health
Microbes must acquire metals for metabolic processes, with nearly a half of all enzymes requiring a metal cofactor for function, yet microbes can be poisoned by metals. The host innate immune ...
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Microbes must acquire metals for metabolic processes, with nearly a half of all enzymes requiring a metal cofactor for function, yet microbes can be poisoned by metals. The host innate immune defenses are thought to exploit these vulnerabilities to protect against invading pathogens, whereas microbes can respond by employing multiple strategies to maintain their metal homeostasis. Understanding these microbial strategies combined with knowledge of diverse metal challenges faced by different microbes in the various host niches could inform the development of new approaches for combating infectious diseases. This chapter summarizes extensive discussions on the interplay of metal ions in host–microbe interactions, from the microbial perspective. Focus is on five key areas: (a) how we define and determine metal availability, (b) the different levels and sources of metals available to microbes in different niches within the host, (c) the effect of the metal status of a pathogen, as derived from its prior environment, on its ability to establish an infection or the severity of disease, (d) the interplay between metals and the microbiota, and (e) how metal restriction and metal oversupply can kill or inhibit the growth of microbes.Less
Microbes must acquire metals for metabolic processes, with nearly a half of all enzymes requiring a metal cofactor for function, yet microbes can be poisoned by metals. The host innate immune defenses are thought to exploit these vulnerabilities to protect against invading pathogens, whereas microbes can respond by employing multiple strategies to maintain their metal homeostasis. Understanding these microbial strategies combined with knowledge of diverse metal challenges faced by different microbes in the various host niches could inform the development of new approaches for combating infectious diseases. This chapter summarizes extensive discussions on the interplay of metal ions in host–microbe interactions, from the microbial perspective. Focus is on five key areas: (a) how we define and determine metal availability, (b) the different levels and sources of metals available to microbes in different niches within the host, (c) the effect of the metal status of a pathogen, as derived from its prior environment, on its ability to establish an infection or the severity of disease, (d) the interplay between metals and the microbiota, and (e) how metal restriction and metal oversupply can kill or inhibit the growth of microbes.
Jerome O. Nriagu and Eric P. Skaar (eds)
- Published in print:
- 2015
- Published Online:
- May 2016
- ISBN:
- 9780262029193
- eISBN:
- 9780262327619
- Item type:
- book
- Publisher:
- The MIT Press
- DOI:
- 10.7551/mitpress/9780262029193.001.0001
- Subject:
- Public Health and Epidemiology, Public Health
Many parts of the world endemic for the most common infectious diseases have the highest prevalence rates of trace metal deficiencies and increasing rates of trace metal pollution. The co-clustering ...
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Many parts of the world endemic for the most common infectious diseases have the highest prevalence rates of trace metal deficiencies and increasing rates of trace metal pollution. The co-clustering of major infectious diseases with trace metal deficiency or toxicity has created a complex web of interactions with serious but poorly understood health repercussions. Infectious diseases can increase human susceptibility to adverse effects of metal exposure while metal excess or deficiency can increase the incidence or severity of infectious diseases. The combined effects of exposure to metals and pathogens on the burden of disease and the mechanisms of interactions between trace metals, pathogens, and the environment have largely been overlooked in animal and human studies. Drawing on expertise from several fields, this book focuses on the distribution, trafficking, fate, and effects of trace metals in biological systems, with the goal of enhancing our understanding of the relationships between homeostatic mechanisms of trace metals and the pathogenesis of infectious diseases. It provides a comprehensive review of current knowledge on vertebrate metal-withholding mechanisms and the strategies employed by different microbes to compete for metals to avoid starvation (or poisoning). State-of-the-art analytical techniques available to investigate pathogen-metal interactions are summarized and open questions highlighted to guide future research. Improving knowledge in these areas will be instrumental to the generation of novel therapeutic countermeasures against infectious diseases.Less
Many parts of the world endemic for the most common infectious diseases have the highest prevalence rates of trace metal deficiencies and increasing rates of trace metal pollution. The co-clustering of major infectious diseases with trace metal deficiency or toxicity has created a complex web of interactions with serious but poorly understood health repercussions. Infectious diseases can increase human susceptibility to adverse effects of metal exposure while metal excess or deficiency can increase the incidence or severity of infectious diseases. The combined effects of exposure to metals and pathogens on the burden of disease and the mechanisms of interactions between trace metals, pathogens, and the environment have largely been overlooked in animal and human studies. Drawing on expertise from several fields, this book focuses on the distribution, trafficking, fate, and effects of trace metals in biological systems, with the goal of enhancing our understanding of the relationships between homeostatic mechanisms of trace metals and the pathogenesis of infectious diseases. It provides a comprehensive review of current knowledge on vertebrate metal-withholding mechanisms and the strategies employed by different microbes to compete for metals to avoid starvation (or poisoning). State-of-the-art analytical techniques available to investigate pathogen-metal interactions are summarized and open questions highlighted to guide future research. Improving knowledge in these areas will be instrumental to the generation of novel therapeutic countermeasures against infectious diseases.
David Wengrow
- Published in print:
- 2013
- Published Online:
- October 2017
- ISBN:
- 9780691159041
- eISBN:
- 9781400848867
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691159041.003.0002
- Subject:
- Archaeology, Historical Archaeology
This chapter examines what led Mikhail Rostovtzeff, an ancient historian, almost a century ago to compare distributions of composite figures from China to Scandinavia. Rostovtzeff is known for his ...
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This chapter examines what led Mikhail Rostovtzeff, an ancient historian, almost a century ago to compare distributions of composite figures from China to Scandinavia. Rostovtzeff is known for his controversial view that the true architects of classical civilization were not those tied to the land, whether as peasant laborers or feudal aristocracy, but rather the middling professional classes of merchants, industrialists, and bankers whose social aspirations were most closely in tune with the civic values of an expanding urban society. Rostovtzeff was also embroiled in debates over the chronological position and cultural affiliations of Bronze Age metal hoards, unearthed along the shores of the Caspian and Black Seas. The chapter considers Rostovtzeff's approach to the interpretation of imagery, and his particular attraction to the imaginary creatures of nomadic art. It might be argued that the movements of monsters offered a kind of visual counterpart to Rostovtzeff's story of an ever-expanding Bronze Age civilization.Less
This chapter examines what led Mikhail Rostovtzeff, an ancient historian, almost a century ago to compare distributions of composite figures from China to Scandinavia. Rostovtzeff is known for his controversial view that the true architects of classical civilization were not those tied to the land, whether as peasant laborers or feudal aristocracy, but rather the middling professional classes of merchants, industrialists, and bankers whose social aspirations were most closely in tune with the civic values of an expanding urban society. Rostovtzeff was also embroiled in debates over the chronological position and cultural affiliations of Bronze Age metal hoards, unearthed along the shores of the Caspian and Black Seas. The chapter considers Rostovtzeff's approach to the interpretation of imagery, and his particular attraction to the imaginary creatures of nomadic art. It might be argued that the movements of monsters offered a kind of visual counterpart to Rostovtzeff's story of an ever-expanding Bronze Age civilization.
Slade A. Loutet, Anson C. K. Chan, Marek J. Kobylarz, Meghan M. Verstraete, Stephanie Pfaffen, Bin Ye, Angel L. Arrieta, and Michael E. P. Murphy
- Published in print:
- 2015
- Published Online:
- May 2016
- ISBN:
- 9780262029193
- eISBN:
- 9780262327619
- Item type:
- chapter
- Publisher:
- The MIT Press
- DOI:
- 10.7551/mitpress/9780262029193.003.0004
- Subject:
- Public Health and Epidemiology, Public Health
Metals are essential for all microorganisms; they are required as cofactors of enzymes that mediate metabolic processes which are indispensable for cellular energy production and growth. Some metals, ...
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Metals are essential for all microorganisms; they are required as cofactors of enzymes that mediate metabolic processes which are indispensable for cellular energy production and growth. Some metals, such as zinc, are readily bound and serve as key structural elements of many macromolecules. Thus, to grow, microorganisms have an essential quota for several metals. The catalytic and other chemical properties of metals that microorganisms value create issues for metal management. Due to their high affinity for amino acids and their reactive nature, uptake, intracellular transport, and storage of metals are mediated by tightly regulated proteins. Protein chaperones function to supply some specific metals to sites of utilization and, in some cases, storage. In particular, iron is difficult to acquire and is stored as a mineral in protein nanocages. Other metals, when present in excess, induce the expression of export systems to maintain a defined intracellular concentration of readily exchangeable metal.Less
Metals are essential for all microorganisms; they are required as cofactors of enzymes that mediate metabolic processes which are indispensable for cellular energy production and growth. Some metals, such as zinc, are readily bound and serve as key structural elements of many macromolecules. Thus, to grow, microorganisms have an essential quota for several metals. The catalytic and other chemical properties of metals that microorganisms value create issues for metal management. Due to their high affinity for amino acids and their reactive nature, uptake, intracellular transport, and storage of metals are mediated by tightly regulated proteins. Protein chaperones function to supply some specific metals to sites of utilization and, in some cases, storage. In particular, iron is difficult to acquire and is stored as a mineral in protein nanocages. Other metals, when present in excess, induce the expression of export systems to maintain a defined intracellular concentration of readily exchangeable metal.
James A. Imlay
- Published in print:
- 2015
- Published Online:
- May 2016
- ISBN:
- 9780262029193
- eISBN:
- 9780262327619
- Item type:
- chapter
- Publisher:
- The MIT Press
- DOI:
- 10.7551/mitpress/9780262029193.003.0005
- Subject:
- Public Health and Epidemiology, Public Health
Transition metals are required for the function of nearly half the enzymatic machinery of organisms. Metals compete for enzyme-binding sites and inappropriate metallation inhibits enzyme function. ...
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Transition metals are required for the function of nearly half the enzymatic machinery of organisms. Metals compete for enzyme-binding sites and inappropriate metallation inhibits enzyme function. Thus microbes work hard to acquire, balance, and sort their metal pools. This chapter surveys common tactics by which bacteria control intracellular iron, manganese, copper, and zinc. Focus is on Escherichia coli, for which enough information is available to attempt an integrated view. High-affinity import systems are regulated at the level of transcription by specific metal-sensing transcription factors. If these importers are insufficient, then metal-sparing strategies are engaged for iron and zinc, the two metals needed to activate essential enzymes. At the other extreme, metal overload can result in chemical injuries (Fe, Zn, Cu) and the mismetallation of noncognate enzymes (Fe, Zn, Mn). Export systems are induced to avoid these outcomes. Cu movement may sometimes be chaperone driven, but other metals may reversibly sample protein-binding sites and populate them according to the relative binding strengths of proteins and competing metabolite ligands. Thus metal pool sizes must be controlled and balanced.Less
Transition metals are required for the function of nearly half the enzymatic machinery of organisms. Metals compete for enzyme-binding sites and inappropriate metallation inhibits enzyme function. Thus microbes work hard to acquire, balance, and sort their metal pools. This chapter surveys common tactics by which bacteria control intracellular iron, manganese, copper, and zinc. Focus is on Escherichia coli, for which enough information is available to attempt an integrated view. High-affinity import systems are regulated at the level of transcription by specific metal-sensing transcription factors. If these importers are insufficient, then metal-sparing strategies are engaged for iron and zinc, the two metals needed to activate essential enzymes. At the other extreme, metal overload can result in chemical injuries (Fe, Zn, Cu) and the mismetallation of noncognate enzymes (Fe, Zn, Mn). Export systems are induced to avoid these outcomes. Cu movement may sometimes be chaperone driven, but other metals may reversibly sample protein-binding sites and populate them according to the relative binding strengths of proteins and competing metabolite ligands. Thus metal pool sizes must be controlled and balanced.
Fudi Wang and Lihong Zhang
- Published in print:
- 2015
- Published Online:
- May 2016
- ISBN:
- 9780262029193
- eISBN:
- 9780262327619
- Item type:
- chapter
- Publisher:
- The MIT Press
- DOI:
- 10.7551/mitpress/9780262029193.003.0006
- Subject:
- Public Health and Epidemiology, Public Health
An increasing amount of evidence shows the linkage between metal ion homeostasis and human disease. Deficiency or overload of metal ions play vital roles in many human diseases, including infectious ...
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An increasing amount of evidence shows the linkage between metal ion homeostasis and human disease. Deficiency or overload of metal ions play vital roles in many human diseases, including infectious disease. Nutritional supplementation and metal-based drugs have been suggested as potential intervention strategies to develop treatment for various diseases related to metal deficiency and overload. However, there are numerous forms of metal ion supplementation and metal-based drugs with different features. This chapter provides an overview of the Recommended Daily Allowance, tolerable upper intake levels, and bioavailability of metal elements and offers perspectives on intervention strategies for metal deficiency and overload. Data for analysis were obtained from research articles, reviews, and reports from the World Health Organization; the National Academic Press websites were another principal source of data.Less
An increasing amount of evidence shows the linkage between metal ion homeostasis and human disease. Deficiency or overload of metal ions play vital roles in many human diseases, including infectious disease. Nutritional supplementation and metal-based drugs have been suggested as potential intervention strategies to develop treatment for various diseases related to metal deficiency and overload. However, there are numerous forms of metal ion supplementation and metal-based drugs with different features. This chapter provides an overview of the Recommended Daily Allowance, tolerable upper intake levels, and bioavailability of metal elements and offers perspectives on intervention strategies for metal deficiency and overload. Data for analysis were obtained from research articles, reviews, and reports from the World Health Organization; the National Academic Press websites were another principal source of data.
Martin Carver
- Published in print:
- 2008
- Published Online:
- September 2012
- ISBN:
- 9780748624416
- eISBN:
- 9780748670703
- Item type:
- book
- Publisher:
- Edinburgh University Press
- DOI:
- 10.3366/edinburgh/9780748624416.001.0001
- Subject:
- Archaeology, Historical Archaeology
This book relates the rediscovery of a monastery of the 8th century AD, one of the earliest so far seen in northern Europe. It lies in north-east Scotland in the land of the Picts, a largely ...
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This book relates the rediscovery of a monastery of the 8th century AD, one of the earliest so far seen in northern Europe. It lies in north-east Scotland in the land of the Picts, a largely forgotten people here shown to have been highly intellectual thinkers and consummate artists. The excavation, one of the largest to have taken place in Scotland, revealed burials in stone cists, over 200 pieces of carved stone grave markers and ornamented cross-slabs, workshops making sacred vessels and vellum for holy books, unusual bag-shaped buildings and a water-mill. The book has three parts: “Exploring”, “The Age of Fame” and :“Legacy”. It tells the story of the investigation, describes what was found and what it means for the history of Scotland and the understanding of early religion for us today. The book is provided at the back with a Digest of Evidence, summarising the archaeological finds, layers, features, structures and the results of survey, making it handy for student use at school and university and essential for fellow archaeologists.Less
This book relates the rediscovery of a monastery of the 8th century AD, one of the earliest so far seen in northern Europe. It lies in north-east Scotland in the land of the Picts, a largely forgotten people here shown to have been highly intellectual thinkers and consummate artists. The excavation, one of the largest to have taken place in Scotland, revealed burials in stone cists, over 200 pieces of carved stone grave markers and ornamented cross-slabs, workshops making sacred vessels and vellum for holy books, unusual bag-shaped buildings and a water-mill. The book has three parts: “Exploring”, “The Age of Fame” and :“Legacy”. It tells the story of the investigation, describes what was found and what it means for the history of Scotland and the understanding of early religion for us today. The book is provided at the back with a Digest of Evidence, summarising the archaeological finds, layers, features, structures and the results of survey, making it handy for student use at school and university and essential for fellow archaeologists.
Vladimir Dobrosavljevic, Nandini Trivedi, and James M. Valles, Jr. (eds)
- Published in print:
- 2012
- Published Online:
- September 2012
- ISBN:
- 9780199592593
- eISBN:
- 9780191741050
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199592593.001.0001
- Subject:
- Physics, Theoretical, Computational, and Statistical Physics
Quantum phase transitions describe the violent rearrangement of electrons or atoms as they evolve from well defined excitations in one phase to a completely different set of excitations in another. ...
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Quantum phase transitions describe the violent rearrangement of electrons or atoms as they evolve from well defined excitations in one phase to a completely different set of excitations in another. The book chapters give insights into how a coherent metallic or superconducting state can be driven into an incoherent insulating state by increasing disorder, magnetic field, carrier concentration and inter-electron interactions. They illustrate the primary methods employed to develop a multi-faceted theory of many interacting particle systems. They describe how recent experiments probing the microscopic structure, transport, charge and spin dynamics have yielded guiding insights. What sets this book apart is this strong dialog between experiment and theory, which reveals the recent progress and emergent opportunities to solve some major problems in many body physics. The pedagogical style of the chapters has been set for graduate students starting in this dynamic field.Less
Quantum phase transitions describe the violent rearrangement of electrons or atoms as they evolve from well defined excitations in one phase to a completely different set of excitations in another. The book chapters give insights into how a coherent metallic or superconducting state can be driven into an incoherent insulating state by increasing disorder, magnetic field, carrier concentration and inter-electron interactions. They illustrate the primary methods employed to develop a multi-faceted theory of many interacting particle systems. They describe how recent experiments probing the microscopic structure, transport, charge and spin dynamics have yielded guiding insights. What sets this book apart is this strong dialog between experiment and theory, which reveals the recent progress and emergent opportunities to solve some major problems in many body physics. The pedagogical style of the chapters has been set for graduate students starting in this dynamic field.
Beverley J. Glover
- Published in print:
- 2007
- Published Online:
- January 2008
- ISBN:
- 9780198565970
- eISBN:
- 9780191714009
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198565970.003.0016
- Subject:
- Biology, Plant Sciences and Forestry
The production of coloured tissues, particularly insect-attracting petals, depends upon the synthesis of pigments. Plants are able to mix, modify and enhance pigments to produce a vast array of final ...
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The production of coloured tissues, particularly insect-attracting petals, depends upon the synthesis of pigments. Plants are able to mix, modify and enhance pigments to produce a vast array of final petal colours. These colours are usually distributed across the flower in patterns, which vary in their degree of regularity and complexity between different species. While colour contrast is much more important than pattern for attracting pollinators from a distance, pattern becomes important at close range and allows animals to distinguish between flowers of different species and to learn to ‘handle’ flowers. This chapter considers the effects of mixing pigments together, the regulation of pigment distribution in the flower, and the use of metals, pH, and cell shape to modify the final colour of the flower.Less
The production of coloured tissues, particularly insect-attracting petals, depends upon the synthesis of pigments. Plants are able to mix, modify and enhance pigments to produce a vast array of final petal colours. These colours are usually distributed across the flower in patterns, which vary in their degree of regularity and complexity between different species. While colour contrast is much more important than pattern for attracting pollinators from a distance, pattern becomes important at close range and allows animals to distinguish between flowers of different species and to learn to ‘handle’ flowers. This chapter considers the effects of mixing pigments together, the regulation of pigment distribution in the flower, and the use of metals, pH, and cell shape to modify the final colour of the flower.
Arne Haaland
- Published in print:
- 2008
- Published Online:
- May 2008
- ISBN:
- 9780199235353
- eISBN:
- 9780191715594
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199235353.003.0010
- Subject:
- Physics, Condensed Matter Physics / Materials
This chapter opens with a discussion of the difficulties of establishing unequivocally whether a monomeric, gaseous Group 2 metal dihalide has a linear or angular equilibrium structure. The ...
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This chapter opens with a discussion of the difficulties of establishing unequivocally whether a monomeric, gaseous Group 2 metal dihalide has a linear or angular equilibrium structure. The accumulated experimental evidence shows that most of these triatomic molecules are linear, but gaseous CaF2, SrF2, SrCl2, and all the barium dihalides are angular. These angular structures are not in accord with the Valence Shell Electron Pair Repulsion (VSEPR) model, but may be rationalized in terms of the polarizable ion model or in terms of sd hybridization on the metal atom. Bond distances and mean bond energies are listed. The bonding may be described in terms of two delocalized (i.e., three-center) or two localized (i.e., two-center) bonding molecular orbitals. The gaseous dihalides of the Group 12 metal atoms are all linear. The bonding radius of Hg is found to be two or three pm smaller than that of Cd, an anomaly which may be due to a combination of the f-block contraction and relativistic effects.Less
This chapter opens with a discussion of the difficulties of establishing unequivocally whether a monomeric, gaseous Group 2 metal dihalide has a linear or angular equilibrium structure. The accumulated experimental evidence shows that most of these triatomic molecules are linear, but gaseous CaF2, SrF2, SrCl2, and all the barium dihalides are angular. These angular structures are not in accord with the Valence Shell Electron Pair Repulsion (VSEPR) model, but may be rationalized in terms of the polarizable ion model or in terms of sd hybridization on the metal atom. Bond distances and mean bond energies are listed. The bonding may be described in terms of two delocalized (i.e., three-center) or two localized (i.e., two-center) bonding molecular orbitals. The gaseous dihalides of the Group 12 metal atoms are all linear. The bonding radius of Hg is found to be two or three pm smaller than that of Cd, an anomaly which may be due to a combination of the f-block contraction and relativistic effects.
Joseph Lemire, Trevor F. Moraes, Vahid Fa Andisi, and Anthony B. Schryvers
- Published in print:
- 2015
- Published Online:
- May 2016
- ISBN:
- 9780262029193
- eISBN:
- 9780262327619
- Item type:
- chapter
- Publisher:
- The MIT Press
- DOI:
- 10.7551/mitpress/9780262029193.003.0002
- Subject:
- Public Health and Epidemiology, Public Health
There is a complex interplay between the vertebrate host and the microbes that inhabit its mucosal surfaces in their competition for essential metal ions. Mucosal surfaces in the host constitute an ...
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There is a complex interplay between the vertebrate host and the microbes that inhabit its mucosal surfaces in their competition for essential metal ions. Mucosal surfaces in the host constitute an array of diverse ecological niches that vary substantially in the availability of metal ions from the external environment and from the host. The microbes that inhabit different mucosal surfaces vary in the degree to which they are uniquely adapted to, and are restricted to, the host mucosal environment. This chapter reviews current understanding of metal ion homeostasis in the host, the mechanisms of metal ion acquisition in microbes, and the degree to which the specific mucosal niche impacts the repertoire of metal ion acquisition mechanisms that the microbes possess.Less
There is a complex interplay between the vertebrate host and the microbes that inhabit its mucosal surfaces in their competition for essential metal ions. Mucosal surfaces in the host constitute an array of diverse ecological niches that vary substantially in the availability of metal ions from the external environment and from the host. The microbes that inhabit different mucosal surfaces vary in the degree to which they are uniquely adapted to, and are restricted to, the host mucosal environment. This chapter reviews current understanding of metal ion homeostasis in the host, the mechanisms of metal ion acquisition in microbes, and the degree to which the specific mucosal niche impacts the repertoire of metal ion acquisition mechanisms that the microbes possess.
Inga Wessels
- Published in print:
- 2015
- Published Online:
- May 2016
- ISBN:
- 9780262029193
- eISBN:
- 9780262327619
- Item type:
- chapter
- Publisher:
- The MIT Press
- DOI:
- 10.7551/mitpress/9780262029193.003.0008
- Subject:
- Public Health and Epidemiology, Public Health
This chapter provides a summary of the functions of essential metallic elements in human metabolism and during infectious diseases as well as their homeostasis during development, maturation, and ...
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This chapter provides a summary of the functions of essential metallic elements in human metabolism and during infectious diseases as well as their homeostasis during development, maturation, and aging. A list of food sources as well as information on the effects of deficiency and excess is provided for each metallic element. As concentrations of metallic contaminants in the environment rise, brief characterizations of nonessential but biologically relevant metallic environmental contaminants have been added. Cases of under-, mal- and overnutrition are increasing worldwide. In combination with decreased nutritional food values, this creates a growing threat for human health, affecting societal and health systems. Potential ways of approaching this problem are suggested and discussed.Less
This chapter provides a summary of the functions of essential metallic elements in human metabolism and during infectious diseases as well as their homeostasis during development, maturation, and aging. A list of food sources as well as information on the effects of deficiency and excess is provided for each metallic element. As concentrations of metallic contaminants in the environment rise, brief characterizations of nonessential but biologically relevant metallic environmental contaminants have been added. Cases of under-, mal- and overnutrition are increasing worldwide. In combination with decreased nutritional food values, this creates a growing threat for human health, affecting societal and health systems. Potential ways of approaching this problem are suggested and discussed.
Tamara García-Barrera
- Published in print:
- 2015
- Published Online:
- May 2016
- ISBN:
- 9780262029193
- eISBN:
- 9780262327619
- Item type:
- chapter
- Publisher:
- The MIT Press
- DOI:
- 10.7551/mitpress/9780262029193.003.0014
- Subject:
- Public Health and Epidemiology, Public Health
The essential or toxic character of the elements depends not only on their concentration, but also on the chemical form in which they occur. This is the case of arsenobetaine, which has limited ...
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The essential or toxic character of the elements depends not only on their concentration, but also on the chemical form in which they occur. This is the case of arsenobetaine, which has limited biological activity compared to the highly toxic inorganic arsenic. Some elements, however, can counteract the toxic action of others through cooperative, competitive, or availability mechanisms. A good example of this is the protective effect of some chemical forms of selenium against mercury toxicity. Cadmium causes the conversion of xanthine dehydrogenase into xanthine oxidase and abnormalities in urate transporters (hyperuricemia), observed in rats under oxidative stress, but cadmium does not have redox properties. This is because cadmium replaces other metals with redox properties. Another example is that toxicity caused by the presence of arsenic in drinking water in countries like Bangladesh is increased through selenium and zinc deficiency detected in the soil. Clearly, the essentiality or toxic character of trace elements cannot be considered in isolation, since it can be modulated by their interaction with the particular organism (its genome), with other elements, and with biomolecules, and is dependent on dose and chemical form.Less
The essential or toxic character of the elements depends not only on their concentration, but also on the chemical form in which they occur. This is the case of arsenobetaine, which has limited biological activity compared to the highly toxic inorganic arsenic. Some elements, however, can counteract the toxic action of others through cooperative, competitive, or availability mechanisms. A good example of this is the protective effect of some chemical forms of selenium against mercury toxicity. Cadmium causes the conversion of xanthine dehydrogenase into xanthine oxidase and abnormalities in urate transporters (hyperuricemia), observed in rats under oxidative stress, but cadmium does not have redox properties. This is because cadmium replaces other metals with redox properties. Another example is that toxicity caused by the presence of arsenic in drinking water in countries like Bangladesh is increased through selenium and zinc deficiency detected in the soil. Clearly, the essentiality or toxic character of trace elements cannot be considered in isolation, since it can be modulated by their interaction with the particular organism (its genome), with other elements, and with biomolecules, and is dependent on dose and chemical form.
M. Leigh Ackland, Julia Bornhorst, George V. Dedoussis, Rodney R. Dietert, Jerome O. Nriagu, Jozef M. Pacyna, and John M. Pettifor
- Published in print:
- 2015
- Published Online:
- May 2016
- ISBN:
- 9780262029193
- eISBN:
- 9780262327619
- Item type:
- chapter
- Publisher:
- The MIT Press
- DOI:
- 10.7551/mitpress/9780262029193.003.0017
- Subject:
- Public Health and Epidemiology, Public Health
By reducing immune function, trace metal deficiencies may substantially contribute to the global burden of diarrhea, pneumonia, and malaria. Human activities may be contributing to trace metal ...
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By reducing immune function, trace metal deficiencies may substantially contribute to the global burden of diarrhea, pneumonia, and malaria. Human activities may be contributing to trace metal deficiency in soils and plants by exacerbating the preponderance of cereals and cash crops that reduce food diversity and micronutrient intake. Adaptive strategies are needed to reverse these trends. Anthropogenic activities have led to increased toxic metal exposure, and effects on human hosts need clarification. Metal toxicities can also impair the immune system and hence increase the susceptibility to infectious pathogens. Climate change affects metal speciation and the build-up of trace elements in the human food chain, with as yet unknown outcomes on infectious disease. Food processing and the use of metallic nanomaterials can alter human exposure to metals in ways that can influence the host–pathogen competition for metals. The effects of metals on human health may also be mediated through modification of the epigenome, conferring drug resistance on pathogenic bacteria and enhancing/ reducing human tolerance to infectious parasites. The emerging metals cerium, gadolinium, lanthanum, and yttrium constitute another driver of change in metal exposure and may potentially modulate the immune system with unknown consequences for human health.Less
By reducing immune function, trace metal deficiencies may substantially contribute to the global burden of diarrhea, pneumonia, and malaria. Human activities may be contributing to trace metal deficiency in soils and plants by exacerbating the preponderance of cereals and cash crops that reduce food diversity and micronutrient intake. Adaptive strategies are needed to reverse these trends. Anthropogenic activities have led to increased toxic metal exposure, and effects on human hosts need clarification. Metal toxicities can also impair the immune system and hence increase the susceptibility to infectious pathogens. Climate change affects metal speciation and the build-up of trace elements in the human food chain, with as yet unknown outcomes on infectious disease. Food processing and the use of metallic nanomaterials can alter human exposure to metals in ways that can influence the host–pathogen competition for metals. The effects of metals on human health may also be mediated through modification of the epigenome, conferring drug resistance on pathogenic bacteria and enhancing/ reducing human tolerance to infectious parasites. The emerging metals cerium, gadolinium, lanthanum, and yttrium constitute another driver of change in metal exposure and may potentially modulate the immune system with unknown consequences for human health.
A. S. Argon
- Published in print:
- 2007
- Published Online:
- September 2007
- ISBN:
- 9780198516002
- eISBN:
- 9780191705717
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198516002.003.0003
- Subject:
- Physics, Crystallography: Physics
Dislocations are the most effective carriers of plasticity in crystalline solids. Under normal circumstances, they are readily generated by purely topological convolution processes as in Frank-Read ...
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Dislocations are the most effective carriers of plasticity in crystalline solids. Under normal circumstances, they are readily generated by purely topological convolution processes as in Frank-Read sources or by double cross slip of screw dislocations, which can in turn produce new Frank-Read sources readily, all at relatively low levels of stress. In BCC metals and strongly directionally bonded solids, the glide of dislocations in their slip planes are resisted by a substantial lattice resistance at low temperatures giving these materials a high intrinsic plastic resistance to begin with. In comparison, in pure close packed FCC and HCP metals the lattice resistance in the best slip systems is normally very small, making it necessary to introduce other extrinsic mechanisms to raise the plastic resistance. This is most effectively accomplished by alloying with a second constituent, which either in the form of a solid solution or as precipitate particles in the host metal can very effectively elevate the resistance to dislocation motion. This chapter starts with a discussion of why a dislocation mechanics view is essential for properly understanding the remarkable effectiveness of strengthening by small volume fractions of second constituents either in solution or in the from of nano-meter sized precipitates, which is both qualitatively and quantitatively missed by a heterogeneous continuum plasticity approach. Following this comparison, the major strengthening mechanisms that will be developed in greater detail in Chapters 4-8 are listed briefly.Less
Dislocations are the most effective carriers of plasticity in crystalline solids. Under normal circumstances, they are readily generated by purely topological convolution processes as in Frank-Read sources or by double cross slip of screw dislocations, which can in turn produce new Frank-Read sources readily, all at relatively low levels of stress. In BCC metals and strongly directionally bonded solids, the glide of dislocations in their slip planes are resisted by a substantial lattice resistance at low temperatures giving these materials a high intrinsic plastic resistance to begin with. In comparison, in pure close packed FCC and HCP metals the lattice resistance in the best slip systems is normally very small, making it necessary to introduce other extrinsic mechanisms to raise the plastic resistance. This is most effectively accomplished by alloying with a second constituent, which either in the form of a solid solution or as precipitate particles in the host metal can very effectively elevate the resistance to dislocation motion. This chapter starts with a discussion of why a dislocation mechanics view is essential for properly understanding the remarkable effectiveness of strengthening by small volume fractions of second constituents either in solution or in the from of nano-meter sized precipitates, which is both qualitatively and quantitatively missed by a heterogeneous continuum plasticity approach. Following this comparison, the major strengthening mechanisms that will be developed in greater detail in Chapters 4-8 are listed briefly.
A. S. Argon
- Published in print:
- 2007
- Published Online:
- September 2007
- ISBN:
- 9780198516002
- eISBN:
- 9780191705717
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198516002.003.0004
- Subject:
- Physics, Crystallography: Physics
One of the most fundamental resistances to dislocation motion is that which the discrete lattice offers in a pure crystalline material in a temperature range where diffusion plays no role. This ...
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One of the most fundamental resistances to dislocation motion is that which the discrete lattice offers in a pure crystalline material in a temperature range where diffusion plays no role. This resistance will be considered from two mechanistically different points of view. First, the Peierls-Nabarro (PN) resistance is considered that results from the pulsing distortions of the dislocation core as it moves through the discrete lattice, affecting often the edge and screw dislocations differently and at very different levels in different crystal structures. Various models of this resistance affecting screw dislocations are examined in detail, leading to consideration of its temperature and strain rate dependence in many BCC metals, and to a lesser extent, in undoped diamond-cubic Si. Second, a form of ubiquitous resistance referred to as phonon drag, that arises from the interaction of moving dislocations with lattice thermal vibrations is presented. It is noted that the temperature dependence of phonon drag is radically different from that of the lattice resistance.Less
One of the most fundamental resistances to dislocation motion is that which the discrete lattice offers in a pure crystalline material in a temperature range where diffusion plays no role. This resistance will be considered from two mechanistically different points of view. First, the Peierls-Nabarro (PN) resistance is considered that results from the pulsing distortions of the dislocation core as it moves through the discrete lattice, affecting often the edge and screw dislocations differently and at very different levels in different crystal structures. Various models of this resistance affecting screw dislocations are examined in detail, leading to consideration of its temperature and strain rate dependence in many BCC metals, and to a lesser extent, in undoped diamond-cubic Si. Second, a form of ubiquitous resistance referred to as phonon drag, that arises from the interaction of moving dislocations with lattice thermal vibrations is presented. It is noted that the temperature dependence of phonon drag is radically different from that of the lattice resistance.
