bluuebunny/crossref_metadata_2025 huggingface dataset:
Climate Change
Authors: Cowie Jonathan
Published: December 2012

The second edition of this acclaimed text has been fully updated and substantially expanded to include the considerable developments (since publication of the first edition) in our understanding of the science of climate change, its impacts on biological and human systems, and developments in climate policy. Written in an accessible style, it provides a broad review of past, present and likely future climate change from the viewpoints of biology, ecology, human ecology and Earth system science. It will again prove to be invaluable to a wide range of readers, from students in the life sciences who need a brief overview of the basics of climate science, to atmospheric science, geography, geoscience and environmental science students who need to understand the biological and human ecological implications of climate change. It is also a valuable reference text for those involved in environmental monitoring, conservation and policy making.
In Search of Power
Authors: Plummer Brenda Gayle
Published: December 2012

In Search of Power is a history of the era of civil rights, decolonization and Black Power. In the critical period from 1956 to 1974, the emergence of newly independent states worldwide and the struggles of the civil rights movement in the United States exposed the limits of racial integration and political freedom. Dissidents, leaders and elites alike were linked in a struggle for power in a world where the rules of the game had changed. Brenda Gayle Plummer traces the detailed connections between African Americans' involvement in international affairs and how they shaped American foreign policy, integrating African American history, the history of the African Diaspora and the history of United States foreign relations. These topics, usually treated separately, not only offer a unified view of the period but also reassess controversies and events that punctuated this colorful era of upheaval and change.
The Works of Francis Bacon
Authors: Bacon Francis
Published: December 2012

Francis Bacon (1561–1626), the English philosopher, statesman and jurist, is best known for developing the empiricist method which forms the basis of modern science. Bacon's writings concentrated on philosophy and judicial reform. His most significant work is the Instauratio Magna comprising two parts - The Advancement of Learning and the Novum Organum. The first part is noteworthy as the first major philosophical work published in English (1605). James Spedding (1808–81) and his co-editors arranged this fourteen-volume edition, published in London between 1857 and 1874, not in chronological order but by subject matter, so that different volumes would appeal to different audiences. The material is divided into three parts: philosophy and general literature; legal works; and letters, speeches and tracts relating to politics. Volume 8, published in 1862, contains letters, and miscellaneous writings relating to Bacon's political duties from 1561 to 1594, offering a valuable insight into Elizabethan statecraft.
Politics and Tradition Between Rome, Ravenna and Constantinople
Authors: Bjornlie M. Shane
Published: December 2012

The Variae of Cassiodorus have long been valued as an epistolary collection offering a window into political and cultural life in a so-called barbarian successor state in sixth-century Italy. However, this study is the first to treat them as more than an assemblage of individual case studies and to analyse the collection's wider historical context. M. Shane Bjornlie highlights the insights the Variae provide into early medieval political, ecclesiastical, fiscal and legal affairs and the influence of the political and military turbulence of Justinian's reconquest of Italy and of political and cultural exchanges between Italy and Constantinople. The book also explores how Cassiodorus revised, updated and assembled the Variae for publication and what this reveals about his motives for publishing an epistolary record and for his own political life at a crucial period of transformation for the Roman world.
Fertility, Education, Growth, and Sustainability
Authors: de la Croix David
Published: December 2012

Fertility choices depend not only on the surrounding culture but also on economic incentives, which have important consequences for inequality, education and sustainability. This book outlines parallels between demographic development and economic outcomes, explaining how fertility, growth and inequality are related. It provides a set of general equilibrium models where households choose their number of children, analysed in four domains. First, inequality is particularly damaging for growth as human capital is kept low by the mass of grown-up children stemming from poor families. Second, the cost of education can be an important determining factor on fertility. Third, fertility is sometimes viewed as a strategic variable in the power struggle between different cultural, ethnic and religious groups. Finally, fertility might be affected by policies targeted at other objectives. Incorporating new findings with the discussion of education policy and sustainability, this book is a significant addition to the literature on growth.
FDR's Ambassadors and the Diplomacy of Crisis
Authors: Mayers David
Published: December 2012

What effect did personality and circumstance have on US foreign policy during World War II? This incisive account of US envoys residing in the major belligerent countries – Japan, Germany, Italy, China, France, Great Britain, USSR – highlights the fascinating role played by such diplomats as Joseph Grew, William Dodd, William Bullitt, Joseph Kennedy and W. Averell Harriman. Between Hitler's 1933 ascent to power and the 1945 bombing of Nagasaki, US ambassadors sculpted formal policy – occasionally deliberately, other times inadvertently – giving shape and meaning not always intended by Franklin D. Roosevelt or predicted by his principal advisors. From appeasement to the Holocaust and the onset of the Cold War, David Mayers examines the complicated interaction between policy, as conceived in Washington, and implementation on the ground in Europe and Asia. By so doing, he also sheds needed light on the fragility, ambiguities and enduring urgency of diplomacy and its crucial function in international politics.
Anarchy and Legal Order
Authors: Chartier Gary
Published: December 2012

This book elaborates and defends the idea of law without the state. Animated by a vision of peaceful, voluntary cooperation as a social ideal and building on a careful account of non-aggression, it features a clear explanation of why the state is illegitimate, dangerous and unnecessary. It proposes an understanding of how law enforcement in a stateless society could be legitimate and what the optimal substance of law without the state might be, suggests ways in which a stateless legal order could foster the growth of a culture of freedom, and situates the project it elaborates in relation to leftist, anti-capitalist and socialist traditions.
Hyperbolization of cocycles by isometries of the Euclidean space
Authors: PONCE MARIO
Published: December 2012

We study hyperbolized versions of cohomological equations that appear with cocycles by isometries of the Euclidean space. These (hyperbolized versions of) equations have a unique continuous solution. We concentrate on the question whether or not these solutions converge to a genuine solution to the original equation, and in what sense we can use them as good approximative solutions. The main advantage of considering solutions to hyperbolized cohomological equations is that they can be easily described, since they are global attractors of a naturally defined skew-product dynamics. We also include some technical results about twisted Birkhoff sums and exponential averaging.
Local Public Opinion: The National Board of Review of Motion Pictures and the Fight against Film Censorship in Virginia, 1916–1922
Authors: FRONC JENNIFER
Published: December 2012

This article examines the conflict that ensued when the National Board of Review of Motion Pictures (a New York City-based organization that opposed any form of legal film censorship) entered the debate over Virginia's state film censor board. Virginia's engagement with film censorship emerged out of its history and politics, particularly in regard to race relations. Elite white Virginians lived in fear both of federal intervention (with the specter of Reconstruction not far behind them) and of a local usurpation of political power by black Virginians. The National Board of Review (NBR) was largely ignorant of this situation, which worked against their goals and ability to cultivate reliable allies. In the 1910s and 1920s, film raised issues about authorities – locally based and oriented versus nationally oriented authority, private authority and municipal, state, and/or federal authority.
An eye for an eye: Reciprocity and the calibration of redress
Authors: Dellis Andrew , Spurrett David
Published: December 2012

General systems for reciprocity explain the same phenomena as the target article's proposed revenge system, and can explain other cooperative phenomena. We need more reason to hypothesise a specific revenge system. In addition, the proposed calculus of revenge is less sensitive to absolute magnitudes of revenge than it should be.
Revenge without redundancy: Functional outcomes do not require discrete adaptations for vengeance or forgiveness
Authors: Holbrook Colin , Fessler Daniel M. T. , Gervais Matthew M.
Published: December 2012

We question whether the postulated revenge and forgiveness systems constitute true adaptations. Revenge and forgiveness are the products of multiple motivational systems and capacities, many of which did not exclusively evolve to support deterrence. Anger is more aptly construed as an adaptation that organizes independent mechanisms to deter transgressors than as the mediator of a distinct revenge adaptation.
Forgiveness is institutionally mediated, not an isolable modular output
Authors: Ross Don
Published: December 2012

McCullough et al. recognize that revenge and forgiveness jointly constitute a functional strategic complex. However, they model the halves of the complex as outputs of modules selected for regulating dyadic relationships. This is backwards. Forgiveness is a culturally evolved institution that can be exapted for use in dyadic contexts; it would be cheap talk among dyads were it not for the shadow of society.
Books and Digital Publishing in Africa: What Does the Future Hold?
Authors: Scott Jacqui
Published: December 2012

There are few generalisations that can be made about Africa, but the huge thirst for knowledge and information throughout the continent is almost certainly one that can. In the past access to written information in Africa has been primarily through printed books. To Western visitors the limited number of books in shops, libraries, and school environments leaps out. A publishing sector that has been limited by lack of investment capital, a large but poor population, and difficult logistics, particularly in rural areas, means that the need for books is not matched by the level of availability and accessibility of books.
High-Resolution Confocal Microscopy with Simultaneous Electron and Laser Beam Irradiation
Authors: Poplawsky Jonathan , Dierolf Volkmar
Published: December 2012

We have developed a fiber-based confocal optical microscope that operates inside of a commercial scanning electron microscope (SEM) instrument (JEOL 6400; JEOL Ltd., Tokyo, Japan) enabling the excitation of a sample either by a laser or by electron beam, and hence combining the complimentary techniques of photoluminescence and cathodoluminescence. The instrument uses single-mode fibers that enter the SEM by vacuum feedthroughs. The illumination and collection fibers operate as effective pinholes providing, in combination with a microscope objective (NA = 0.3), high spatial resolution (~2 μm) and excellent collection efficiency. The high spatial resolution ensures that the light collected from the sample is in a region of optimal laser beam and electron beam overlap. The capabilities of this instrument are tested by experiments involving the excitation of europium ions in situ doped in GaN thin films.
Die Bedeutung von Schlaf und Schlafstörungen für Lernen und Gedächtnis bei Kindern – ein Überblick
Authors: Schlarb Angelika A. , Milicevic Vesna , Schwerdtle Barbara , Nuerk Hans-Christoph
Published: December 2012

Zusammenfassung: Schlafstörungen im Kindesalter sind weit verbreitet. Häufig wirken sich kindliche Schlafprobleme auf die kognitive Leistungsfähigkeit und damit auf die schulischen Leistungen aus. Ziel der vorliegenden Arbeit war es, eine Übersicht über den Zusammenhang zwischen den Schlafparametern Nachtschlaf, Schlafdauer, Schlafeffizienz, Schlafqualität, Schlafprobleme sowie der kognitiven und schulischen Leistungsfähigkeit im Kindesalter (fünf bis 13 Jahre) zu geben. Einige der 25 gefundenen Studien konnten aufzeigen, dass der Nachtschlaf den Kindern das Lernen erleichtert. Dabei konnten Aufgaben, die keine tiefen Verarbeitungsprozesse benötigten, von Kindern mit Schlafeinbußen zumeist kompensiert werden, Aufgaben mit tieferen Verarbeitungsprozessen hingegen häufig nicht. Der Nachtschlaf scheint sich in diesem Alter vor allem auf die deklarative Gedächtnisleistung positiv auszuwirken. Demnach scheint die Gedächtniskonsolidierung während des Schlafs vom Typ des Lernmaterials abzuhängen. Eine zu kurze Schlafdauer, zu geringe Schlafeffizienz und das Vorhandensein von Schlafproblemen hängen überwiegend mit Einbußen bei kognitiven Lernprozessen im Kindesalter zusammen. Hingegen korrelierten subjektive Schlafqualität und Lernen nicht miteinander. Insgesamt existieren noch wenige Studien, die den Zusammenhang zwischen den verschiedenen Schlafparametern und kognitiven Prozessen der Kinder untersuchen. Weitere systematische Studien sind daher sinnvoll und notwendig, die überdies beeinflussende Variablen, wie zum Beispiel elterliche Kontrolle, in die Betrachtung einbeziehen. Da Schlafstörungen bei Kindern eine Gefahr für die kognitive und schulische Entwicklung darstellen, sollten sie frühzeitig diagnostiziert werden. Daher sollten Eltern, Lehrer und alle in der Erziehung tätigen Praktiker über ein ausreichendes Wissen zu den Symptomen und Folgen schlechten Schlafs bei Kindern sowie über geeignete Präventions- und Interventionsmöglichkeiten verfügen. Gezielte Förderprogramme zur Verbesserung der schulischen und kognitiven Leistungen der Kinder könnten eingesetzt werden.
Mountain building and mantle dynamics
Authors: Faccenna Claudio , Becker Thorsten W. , Conrad Clinton P. , Husson Laurent
Published: December 2012

Mountain building at convergent margins requires tectonic forces that can overcome frictional resistance along large‐scale thrust faults and support the gravitational potential energy stored within the thickened crust of the orogen. A general, dynamic model for this process is still lacking. Here we propose that mountain belts can be classified between two end‐members. First, those of “slab pull” type, where subduction is mainly confined to the upper mantle, and rollback trench motion lead to moderately thick crustal stacks, such as in the Mediterranean. Second, those of “slab suction” type, where whole‐mantle convection cells (“conveyor belts”) lead to the more extreme expressions of orogeny, such as the largely thickened crust and high plateaus of present‐day Tibet and the Altiplano. For the slab suction type, deep mantle convection produces the unique conditions to drag plates toward each other, irrespective of their nature and other boundary conditions. We support this hypothesis by analyzing the orogenic, volcanic, and convective history associated with the Tertiary formation of the Andes after ~40 Ma and Himalayas after collision at ~55 Ma. Based on mantle circulation modeling and tectonic reconstructions, we surmise that the forces necessary to sustain slab‐suction mountain building in those orogens derive, after transient slab ponding, from the mantle drag induced upon slab penetration into the lower mantle, and from an associated surge of mantle upwelling beneath Africa. This process started at ~65–55 Ma for Tibet‐Himalaya, when the Tethyan slab penetrated into the lower mantle, and ~10 Myr later in the Andes, when the Nazca slab did. This surge of mantle convection drags plates against each other, generating the necessary compressional forces to create and sustain these two orogenic belts. If our model is correct, the available geological records of orogeny can be used to decipher time‐dependent mantle convection, with implications for the supercontinental cycle.
Rise to dominance of angiosperm pioneers in European Cretaceous environments
Authors: Coiffard Clément , Gomez Bernard , Daviero-Gomez Véronique , Dilcher David L.
Published: December 2012

The majority of environments are dominated by flowering plants today, but it is uncertain how this dominance originated. This increase in angiosperm diversity happened during the Cretaceous period (
ca.
145–65 Ma) and led to replacement and often extinction of gymnosperms and ferns. We propose a scenario for the rise to dominance of the angiosperms from the Barremian (
ca.
130 Ma) to the Campanian (
ca.
84 Ma) based on the European megafossil plant record. These megafossil data demonstrate that angiosperms migrated into new environments in three phases: (
i
) Barremian (
ca.
130–125 Ma) freshwater lake-related wetlands; (
ii
) Aptian–Albian (
ca.
125–100 Ma) understory floodplains (excluding levees and back swamps); and (
iii
) Cenomanian–Campanian (
ca.
100–84 Ma) natural levees, back swamps, and coastal swamps. This scenario allows for the measured evolution of angiosperms in time and space synthesizing changes in the physical environment with concomitant changes in the biological environment. This view of angiosperm radiation in three phases reconciles previous scenarios based on the North American record. The Cretaceous plant record that can be observed in Europe is exceptional in many ways. (
i
) Angiosperms are well preserved from the Barremian to the Maastrichtian (
ca.
65 Ma). (
ii
) Deposits are well constrained and dated stratigraphically. (
iii
) They encompass a full range of environments. (
iv
) European paleobotany provides many detailed studies of Cretaceous floras for analysis. These factors make a robust dataset for the study of angiosperm evolution from the Barremian to the Campanian that can be traced through various ecosystems and related to other plant groups occupying the same niches.
Running as a resource of hope? Voices from Eldoret
Authors: Jarvie Grant , Sikes Michelle
Published: December 2012

There is a continuing debate about East African running success. Few studies have considered wealth as a key motivation behind wanting to run. This article focuses upon the motivations of Kenyan women who choose to participate in professional running and the impact on them, their families and wider communities. Much of the fieldwork for this study took place in and around the town of Eldoret. It encourages researchers interested in sport in Africa to develop a political economy approach to running and to critically evaluate the claims made for sport as a resource of hope.

[L'entreprenariat en tant que ressource d'espoir? Des voix s'élèvent depuis Eldoret.] Il y a un débat qui se poursuit au sujet du succès dans l'émergence de l'Afrique de l'Est. Peu d'études ont considéré la richesse comme étant une motivation clé derrière le désir d'entreprendre. Cet article se concentre sur les motivations des femmes kenyanes qui choisissent de participer à la gestion d'entreprise et son impact sur elles, sur leurs familles et sur les communautés plus étendues. Une grande partie du travail sur le terrain et pour cette étude, a eu lieu dans et autour de la ville d'Eldoret. Il encourage les chercheurs qui s'intéressent au sport en Afrique à développer une approche d'économie politique à l'exécution et à l'évaluation critique des demandes formulées pour le sport en tant que ressource d'espoir.

Mots-clés: courir au Kenya  ; les femmes  ; les chances de la vie  ; les motivations  ; les richesses  ; les ressources
Rear surface protection and front surface bi-layer passivation for silicon nanostructure-textured solar cells
Authors: Dou Bingfei , Jia Rui , Li Haofeng , Chen Chen , Ding Wuchang , Meng Yanlong , Liu Xinyu , Ye Tianchun
Published: December 2012

Silicon nanostructure arrays were synthesized via Ag-catalysed chemical etching on solar cells. In contrast to the traditional etching in HF/AgNO3, the new technique used in this work produced nanostructure textures located only on the front surface of the cells. Furthermore, a SiO2/SiN
X
bi-layer was used to passivate the surface of the cells. By these optimizations, nanostructure-textured cells' performance was improved. The data obtained from this work are fundamental and has some reference value for future studies.
Achieving concentrated graphene dispersions in water/acetone mixtures by the strategy of tailoring Hansen solubility parameters
Authors: Yi Min , Shen Zhigang , Zhang Xiaojing , Ma Shulin
Published: December 2012

Although exfoliating graphite to give graphene paves a new way for graphene preparation, a general strategy of low-boiling-point solvents and high graphene concentration is still highly required. In this study, using the strategy of tailoring Hansen solubility parameters (HSP), a method based on exfoliation of graphite in water/acetone mixtures is demonstrated to achieve concentrated graphene dispersions. It is found that in the scope of blending two mediocre solvents, tailoring the HSP of water/acetone mixtures to approach the HSP of graphene could yield graphene dispersions at a high concentration of up to 0.21 mg ml−1. The experimentally determined optimum composition of the mixtures occurs at an acetone mass fraction of ∼75%. The trend of concentration varying with mixture compositions could be well predicated by the model, which relates the concentration to the mixing enthalpy within the scope of HSP theory. The resultant dispersion is highly stabilized. Atomic force microscopic statistical analysis shows that up to ∼50% of the prepared nanosheets are less than 1 nm thick after 4 h sonication and 114g centrifugation. Analyses based on diverse characterizations indicate the graphene sheets to be largely free of basal plane defects and oxidation. The filtered films are also investigated in terms of their electrical and optical properties to show reasonable conductivity and transparency. The strategy of tailoring HSP, which can be easily extended to various solvent systems, and water/acetone mixtures here, extends the scope for large-scale production of graphene in low-boiling-point solutions.
Electrical and spectroscopic characterization of a surgical argon plasma discharge
Authors: Keller Sandra , Bibinov Nikita , Neugebauer Alexander , Awakowicz Peter
Published: December 2012

For electrosurgical procedures, the argon plasma coagulation (APC) discharge is a well-established atmospheric-pressure plasma tool for thermal haemostasis and devitalization of biological tissue. To characterize this plasma source, voltage–current measurements, microphotography, optical emission spectroscopy and numerical simulation are applied. Two discharge modes are established during the operation of the APC plasma source. A short transient spark discharge is ignited within the positive half period of the applied high voltage after a streamer channel connects the APC probe and the counter-electrode. During the second phase, which continues under negative high voltage, a glow discharge is stabilized in the plasma channel.
Comparison of hybrid and baseline ELMy H-mode confinement in JET with the carbon wall
Authors: Beurskens M.N.A. , Frassinetti L. , Challis C. , Osborne T. , Snyder P.B. , Alper B. , Angioni C. , Bourdelle C. , Buratti P. , Crisanti F. , Giovannozzi E. , Giroud C. , Groebner R. , Hobirk J. , Jenkins I. , Joffrin E. , Leyland M.J. , Lomas P. , Mantica P. , McDonald D. , Nunes I. , Rimini F. , Saarelma S. , Voitsekhovitch I. , de Vries P. , Zarzoso D.
Published: December 2012

The confinement in JET baseline type I ELMy H-mode plasmas is compared to that in so-called hybrid H-modes in a database study of 112 plasmas in JET with the carbon fibre composite (CFC) wall. The baseline plasmas typically have β
N ∼ 1.5–2, H
98 ∼ 1, whereas the hybrid plasmas have β
N ∼ 2.5–3, H
98 < 1.5. The database study contains both low- (δ ∼ 0.2–0.25) and high-triangularity (δ ∼ 0.4) hybrid and baseline H-mode plasmas from the last JET operational campaigns in the CFC wall from the period 2008–2009. Based on a detailed confinement study of the global as well as the pedestal and core confinement, there is no evidence that the hybrid and baseline plasmas form separate confinement groups; it emerges that the transition between the two scenarios is of a gradual kind rather than demonstrating a bifurcation in the confinement. The elevated confinement enhancement factor H
98 in the hybrid plasmas may possibly be explained by the density dependence in the τ
98 scaling as n
0.41 and the fact that the hybrid plasmas operate at low plasma density compared to the baseline ELMy H-mode plasmas. A separate regression on the confinement data in this study shows a reduction in the density dependence as n
0.09±0.08. Furthermore, inclusion of the plasma toroidal rotation in the confinement regression provides a scaling with the toroidal Alfvén Mach number as

and again a reduced density dependence as n
0.15±0.08. The differences in pedestal confinement can be explained on the basis of linear MHD stability through a coupling of the total and pedestal poloidal pressure and the pedestal performance can be improved through plasma shaping as well as high β operation. This has been confirmed in a comparison with the EPED1 predictive pedestal code which shows a good agreement between the predicted and measured pedestal pressure within 20–30% for a wide range of β
N ∼ 1.5–3.5. The core profiles show a strong degree of pressure profile consistency. No beneficial effect of core density peaking on confinement could be identified for the majority of the plasmas presented here as the density peaking is compensated by a temperature de-peaking resulting in no or only a weak variation in the pressure peaking. The core confinement could only be optimized in case the ions and electrons are decoupled, in which case the ion temperature profile peaking can be enhanced, which benefits confinement. In this study, the latter has only been achieved in the low-triangularity hybrid plasmas, and can be attributed to low-density operation. Plasma rotation has been found to reduce core profile stiffness, and can explain an increase in profile peaking at small radius ρ
tor = 0.3.
Particle Distribution and Composition of Retail Whole Wheat Flours Separated by Sieving
Authors: Doblado‐Maldonado Andrés F. , Rose Devin J.
Published: December 2012

The purpose of this study was to evaluate the differences among four retail whole wheat flours with respect to particle size distribution and composition of fractions separated by sieving. Interestingly, not only were significant differences discovered among the brands for particle size distribution, but lots within two of the brands were significantly different (P < 0.05), suggesting that flour particle size produced by the same company is not always consistent. Starch damage ranged from 4.67 to 7.69%. As expected, darker colors were associated with the larger particle size fractions, and the colors lightened as particle size decreased. This observation suggested that the differences in particle size resulted from differences in the degree to which the bran fraction of the kernel was milled, an observation substantiated by the distribution of ash in each fraction, which ranged from 0.37 to 38.0% of total ash. Distribution of protein ranged from 0.19 to 61.8% of total protein. These data are relevant because differences in particle size distribution and composition affect functionality, sensory acceptability, nutritional properties, and shelf life of whole wheat flour.
The rpg4-Mediated Resistance to Wheat Stem Rust (Puccinia graminis) in Barley (Hordeum vulgare) Requires Rpg5, a Second NBS-LRR Gene, and an Actin Depolymerization Factor
Authors: Wang X. , Richards J. , Gross T. , Druka A. , Kleinhofs A. , Steffenson B. , Acevedo M. , Brueggeman R.
Published: December 2012

The rpg4 gene confers recessive resistance to several races of wheat stem rust (Puccinia graminis f. sp. tritici) and Rpg5 provides dominant resistance against isolates of the rye stem rust (P. graminis f. sp. secalis) in barley. The rpg4 and Rpg5 genes are tightly linked on chromosome 5H, and positional cloning using high-resolution populations clearly separated the genes, unambiguously identifying Rpg5; however, the identity of rpg4 remained unclear. High-resolution genotyping of critical recombinants at the rpg4/Rpg5 locus, designated here as rpg4-mediated resistance locus (RMRL) delimited two distinct yet tightly linked loci required for resistance, designated as RMRL1 and RMRL2. Utilizing virus-induced gene silencing, each gene at RMRL1, i.e., HvRga1 (a nucleotide-binding site leucine-rich repeat [NBS-LRR] domain gene), Rpg5 (an NBS-LRR-protein kinase domain gene), and HvAdf3 (an actin depolymerizing factor-like gene), was individually silenced followed by inoculation with P. graminis f. sp. tritici race QCCJ. Silencing each gene changed the reaction type from incompatible to compatible, indicating that all three genes are required for rpg4-mediated resistance. This stem rust resistance mechanism in barley follows the emerging theme of unrelated pairs of genetically linked NBS-LRR genes required for specific pathogen recognition and resistance. It also appears that actin cytoskeleton dynamics may play an important role in determining resistance against several races of stem rust in barley.
The oldest dinosaur? A Middle Triassic dinosauriform from Tanzania
Authors: Nesbitt Sterling J. , Barrett Paul M. , Werning Sarah , Sidor Christian A. , Charig Alan J.
Published: December 2012

The rise of dinosaurs was a major event in vertebrate history, but the timing of the origin and early diversification of the group remain poorly constrained. Here, we describe
Nyasasaurus parringtoni
gen. et sp. nov., which is identified as either the earliest known member of, or the sister–taxon to, Dinosauria.
Nyasasaurus
possesses a unique combination of dinosaur character states and an elevated growth rate similar to that of definitive early dinosaurs. It demonstrates that the initial dinosaur radiation occurred over a longer timescale than previously thought (possibly 15 Myr earlier), and that dinosaurs and their immediate relatives are better understood as part of a larger Middle Triassic archosauriform radiation. The African provenance of
Nyasasaurus
supports a southern Pangaean origin for Dinosauria.
On the dynamics of neutral mutations in a mathematical model for a homogeneous stem cell population
Authors: Traulsen Arne , Lenaerts Tom , Pacheco Jorge M. , Dingli David
Published: December 2012

The theory of the clonal origin of cancer states that a tumour arises from one cell that acquires mutation(s) leading to the malignant phenotype. It is the current belief that many of these mutations give a fitness advantage to the mutant population allowing it to expand, eventually leading to disease. However, mutations that lead to such a clonal expansion need not give a fitness advantage and may in fact be neutral—or almost neutral—with respect to fitness. Such mutant clones can be eliminated or expand stochastically, leading to a malignant phenotype (disease). Mutations in haematopoietic stem cells give rise to diseases such as chronic myeloid leukaemia (CML) and paroxysmal nocturnal haemoglobinuria (PNH). Although neutral drift often leads to clonal extinction, disease is still possible, and in this case, it has important implications both for the incidence of disease and for therapy, as it may be more difficult to eliminate neutral mutations with therapy. We illustrate the consequences of such dynamics, using CML and PNH as examples. These considerations have implications for many other tumours as well.
An improved failure criterion for biological and engineered staggered composites
Authors: Barthelat Francois , Dastjerdi Ahmad Khayer , Rabiei Reza
Published: December 2012

High-performance biological materials such as nacre, spider silk or bone have evolved a staggered microstructure consisting of stiff and strong elongated inclusions aligned with the direction of loading. This structure leads to useful combinations of stiffness, strength and toughness, and it is therefore increasingly mimicked in bio-inspired composites. The performance of staggered composites can be tuned; for example, their mechanical properties increase when the overlap between the inclusions is increased. However, larger overlaps may lead to excessive tensile stress and fracture of the inclusions themselves, a highly detrimental failure mode. Fracture of the inclusions has so far only been predicted using highly simplified models, which hinder our ability to properly design and optimize engineered staggered composites. In this work, we develop a new failure criterion that takes into account the complex stress field within the inclusions as well as initial defects. The model leads to an ‘optimum criterion’ for cases where the shear tractions on the inclusions is uniform, and a ‘conservative’ criterion for which the tractions are modelled as point forces at the ends of the overlap regions. The criterion can therefore be applied for a wide array of material behaviour at the interface, even if the details of the shear load transfer is not known. The new criterion is validated with experiments on staggered structures made of millimetre-thick alumina tablets, and by comparison with data on nacre. Formulated in a non-dimensional form, our new criterion can be applied on a wide variety of engineered staggered composites at any length scale. It also reveals new design guidelines, for example high aspect ratio inclusions with weak interfaces are preferable over inclusions with low aspect ratio and stronger interfaces. Together with existing models, this new criterion will lead to optimal designs that harness the full potential of bio-inspired staggered composites.
Modelling the sputtering of Au surfaces using a multi time-scale technique
Authors: Scott Chris , Smith Roger
Published: December 2012

We present results from an atomistic computer simulation model of the sputtering of gold crystal surfaces under 500 eV ion bombardment by Au and Ar ions for doses up to 10
14
 ions cm
−2
. The multi time-scale technique uses molecular dynamics to calculate the fast ballistic collision processes in the early stages of the cascade, whereas an on-the fly kinetic Monte Carlo technique is used to model the relaxation and diffusion processes between successive ion impacts when the defect motion has begun to be dominated by rare events. The results indicate a large amount of crystalline recovery between impacts, some facetting of the crystal surfaces but no large sub-surface defect accumulation. Because of this recovery process, sputtering yields and energy distributions are in good agreement with those obtained assuming a perfect crystal surface and also with those experimentally measured.
Direct evidence for encoding of motion streaks in human visual cortex
Authors: Apthorp Deborah , Schwarzkopf D. Samuel , Kaul Christian , Bahrami Bahador , Alais David , Rees Geraint
Published: December 2012

Temporal integration in the visual system causes fast-moving objects to generate static, oriented traces (‘motion streaks’), which could be used to help judge direction of motion. While human psychophysics and single-unit studies in non-human primates are consistent with this hypothesis, direct neural evidence from the human cortex is still lacking. First, we provide psychophysical evidence that faster and slower motions are processed by distinct neural mechanisms: faster motion raised human perceptual thresholds for static orientations parallel to the direction of motion, whereas slower motion raised thresholds for orthogonal orientations. We then used functional magnetic resonance imaging to measure brain activity while human observers viewed either fast (‘streaky’) or slow random dot stimuli moving in different directions, or corresponding static-oriented stimuli. We found that local spatial patterns of brain activity in early retinotopic visual cortex reliably distinguished between static orientations. Critically, a multivariate pattern classifier trained on brain activity evoked by these
static
stimuli could then successfully distinguish the
direction
of fast (‘streaky’) but not slow motion. Thus, signals encoding static-oriented streak information are present in human early visual cortex when viewing fast motion. These experiments show that motion streaks are present in the human visual system for faster motion.
Groups of related belugas (Delphinapterus leucas) travel together during their seasonal migrations in and around Hudson Bay
Authors: Colbeck Gabriel J. , Duchesne Pierre , Postma Lianne D. , Lesage Véronique , Hammill Mike O. , Turgeon Julie
Published: December 2012

Social structure involving long-term associations with relatives should facilitate the learning of complex behaviours such as long-distance migration. In and around Hudson Bay (Canada), three stocks of beluga whales form a panmictic unit, but have different migratory behaviours associated with different summering areas. We analysed genetic variation at 13 microsatellite loci among 1524 belugas, to test hypotheses about social structure in belugas. We found significant proportions of mother–offspring pairs throughout the migratory cycle, but average relatedness extended beyond close kinship only during migration. Average relatedness was significantly above random expectations for pairs caught at the same site but on different days or months of a year, suggesting that belugas maintain associations with a network of relatives during migration. Pairs involving a female (female–female or male–female) were on average more related than pairs of males, and males seemed to disperse from their matrilineal group to associate with other mature males. Altogether, our results indicate that relatives other than strictly parents, and especially females, play a role in maintaining a social structure that could facilitate the learning of migration routes. Cultural conservatism may limit contributions from nearby summer stocks to endangered stocks such as the Eastern Hudson Bay beluga.
The role of individuality in collective group movement
Authors: Herbert-Read J. E. , Krause S. , Morrell L. J. , Schaerf T. M. , Krause J. , Ward A. J. W.
Published: December 2012

How different levels of biological organization interact to shape each other's function is a central question in biology. One particularly important topic in this context is how individuals' variation in behaviour shapes group-level characteristics. We investigated how fish that express different locomotory behaviour in an asocial context move collectively when in groups. First, we established that individual fish have characteristic, repeatable locomotion behaviours (i.e. median speeds, variance in speeds and median turning speeds) when tested on their own. When tested in groups of two, four or eight fish, we found individuals partly maintained their asocial median speed and median turning speed preferences, while their variance in speed preference was lost. The strength of this individuality decreased as group size increased, with individuals conforming to the speed of the group, while also decreasing the variability in their own speed. Further, individuals adopted movement characteristics that were dependent on what group size they were in. This study therefore shows the influence of social context on individual behaviour. If the results found here can be generalized across species and contexts, then although individuality is not entirely lost in groups, social conformity and group-size-dependent effects drive how individuals will adjust their behaviour in groups.
Adherence to MRI protocol consensus guidelines in multiple sclerosis: An Australian multi‐centre study
Authors: Curley Michael , Josey Lawrence , Lucas Robyn , Dear Keith , Taylor Bruce V , Coulthard Alan ,   Ausimmune Investigator Group, Chapman Caron , Coulthard Alan , Dear Keith , Dwyer Terry , Kilpatrick Trevor , Lucas Robyn , McMichael Tony , Pender Michael P , Ponsonby Anne‐Louise , Taylor Bruce , Valery Patricia , van der Mei Ingrid , Williams David
Published: December 2012

Introduction

Multiple sclerosis (MS) is a debilitating disease that causes significant morbidity within a young demographic. Diagnostic guidelines for MS have evolved, and imaging has played an increasingly important role in diagnosis over the last two decades. For imaging to contribute to diagnosis in a meaningful way, it must be reproducible. Consensus guidelines for MRI in MS exist to define correct sequence type and imaging technique, but it is not clear to what extent they are followed. This study reviewed MRI studies performed on Australian individuals presenting with a first clinical diagnosis of central nervous system demyelination (FCD) for adherence to published guidelines and discussed practical implementation of MS guidelines in light of recent updates.

Methods

The Ausimmune study was a prospective case control study of Australian participants presenting with FCD from 2003 to 2006. Baseline cranial and spinal cord MRI studies of 226 case participants from four separate Australian regions were reviewed. MRI sequences were classified according to anatomical location, slice plane, tissue weighting and use of gadolinium‐containing contrast media. Results were compared with the 2003 Consortium of Multiple Sclerosis Centres MRI protocol for the diagnosis of MS.

Results

The composition of core cranial MRI sequences performed varied across the 226 scans. Of the studies, 91% included sagittal fluid attenuated inversion recovery (FLAIR) sequences. Cranial axial T2‐weighted, axial FLAIR and axial proton density‐weighted sequences were performed in 88%, 60% and 16% (respectively) of scans. Only 25% of the studies included a T1‐weighted contrast‐enhanced sequence. Concordance with the guidelines in all sequences was very low (2).

Conclusion

Only a small number of MRI investigations performed included all of the sequences stipulated by consensus guidelines. This is likely due to poor awareness in the imaging community of the guidelines and the rationale behind certain sequences. Radiologists with a sub‐speciality interest in neuroradiology should take ownership of this issue and ensure that recommended imaging guidelines are followed.
Regional venous oxygen saturation versus mixed venous saturation after paediatric cardiac surgery
Authors: MORENO G. E. , PILÁN M. L. , MANARA C. , MAGLIOLA R. , VASSALLO J. C. , BALESTRINI M. , LENZ A. M. , KRYNSKI M. , ALTHABE M. , LANDRY L.
Published: December 2012

Background

Central venous oxygen saturation (ScvO2) remains the gold standard surrogate for tissue oxygen extraction in paediatric cardiac surgery. Near‐infrared spectroscopy (NIRS) has been developed as a non‐invasive diagnostic tool for regional oxygen saturation. The aim was to compare regional oxygen saturation measured by NIRS with ScvO2 in postoperative paediatric cardiac patients.

Methods

In this prospective study, we included newborns and infants younger than 45 days undergoing heart surgery. We recorded continuous ScvO2 and NIRS regional saturation placed on the forehead (B) and right flank (S) for 48 h postoperatively. A Bland–Altman's analysis was used to assess the agreement between these measurements.

Results

A total of 23 patients were included with a median age of 12 days (2–46) and median weight of 3.1 kg (2.3–4.47). The mean difference (MD) ScvO2‐ B NIRS was 10.45% with limits of agreement (LOA) −17.23 to 38.13% and ScvO2‐ S NIRS MD 7.16% with LOA: −25.51 to 39.84%. The single ventricle ScvO2‐ S NIRS subgroup had MD within ± 5%; however, wide LOA was observed. The remaining subgroups showed MD nearly above ± 5%, with wide LOA.

Conclusions

The regional oxygen saturation of brain and kidney did not match ScvO2 as estimation of global tissue perfusion. Nevertheless, NIRS may still provide information regarding regional circulation that may help in the management of neonatal cardiac surgery patients.
Ethical Considerations in Education Research in Emergency Medicine
Authors: Kraus Chadd K. , Guth Todd , Richardson Derek , Kane Bryan , Marco Catherine A.
Published: December 2012

The 2012 Academic Emergency Medicine consensus conference on education research in emergency medicine (EM) addressed various issues, including that of ethics in medical education research for EM. Education research in EM is essential to patient care and safety, and with recent advances in simulation and the advent of the Milestones project, it will become even more vital. Education research in EM is guided by the same principles that guide the ethical conduct of all human subjects' research: respect for persons, beneficence, and justice. Regulatory provisions and widely accepted ethical standards provide a framework for research in EM education; however, special considerations exist for education research. To ensure patient and trainee safety and to maintain the integrity of new knowledge, ethical considerations should remain at the forefront of EM education research. For EM education researchers, recognition of the vulnerability of residents, medical students, and others as research subjects is paramount. This article fills an important gap by outlining the principles guiding education research in EM, exploring the ethical challenges and approaches to education research, and offering a framework and future directions for the ethical conduct of education research in EM.
Reflections on the Consensus Process: A Leadership Role for Emergency Medicine in Educational Scholarship and Practice Across Health Care
Authors: Gordon James A.
Published: December 2012

In just a few decades, emergency medicine (EM) has assumed a leadership role in medical education across many academic medical centers. This rapid evolution suggests medical education as a natural priority area for EM scholarship. This year's Academic Emergency Medicine consensus conference provides an ideal forum to focus on educational research as a core element of the specialty's academic portfolio.
Mothers with intellectual disability and their babies: a population warranting special consideration
Authors: LLEWELLYN GWYNNYTH
Published: December 2012

Biological factors and/or the mothers’ social‐environmental situation may be responsible for the much higher relative risk for pregnant intellectually disabled women and their newborns reported in articles by Höglund et al. in this issue. This population has increased exposure to key social determinants of health such as poverty and social exclusion. This is compounded by institutional discriminatory beliefs and practices. People with intellectual disability may also struggle to communicate their needs effectively and to be heard and understood by health professionals. Further research is warranted to understand the reasons for two stand‐out findings: why rates of stillbirth and perinatal death are significantly higher in this group and whether varying obstetric practices are responsible for the significantly lower use of pain relief during childbirth. Quality health care requires that due attention is given to meeting the specific needs of this vulnerable group of mothers and their newborns.