bluuebunny/crossref_metadata_2025 huggingface dataset:
Applying Neuroscientific Findings to Education: The Good, the Tough, and the Hopeful
Authors: Christoff Kalina
Published: May 2008

ABSTRACT— Advances in neuroscience during the past century have yielded important insights into mental functioning, but their implications for the field of education have remained largely unexplored. In a bold attempt to bridge this gap, Immordino‐Yang presents findings from 2 boys, Nico and Brooke, each of whom lost half of his brain. The remarkable recovery of functions in the 2 boys highlights the degree to which children’s emotional and social experiences shape brain development, as well as the importance of plasticity. Immordino‐Yang places emphasis on cognitive plasticity—the ability to use different strategies in solving a task—which is clearly evident in the boys’ performance. It is possible, however, that neural plasticity may have occurred as well, either prior to or after surgery. Although it may not be possible to distinguish between cognitive and neural plasticity at this point, Immordino‐Yang makes a crucial contribution. By placing these findings in an educational context and presenting their implications in a clear and compelling fashion, she successfully brings neuroscience and education a notch closer.
Varied Developmental Trajectories: Lessons for Educators
Authors: Snow Catherine E.
Published: May 2008

ABSTRACT— Methodological ingenuity and deep knowledge of expected development are combined by Immordino‐Yang to produce an enlightening analysis of 2 hemispherectomized youths. Specific lessons to be drawn from her article include the following: the limitations of anatomy in predicting function; the need for educators to understand fully the multifunctionality, plasticity, and experience‐driven development of cortical structures; the importance of a wide‐ranging and multilayered approach to assessment when it is being used for diagnostic purposes; and, finally, the difficulty (and importance) of distinguishing task accomplishment from procedures undertaken while performing the task. Carefully documented stories like those told by Immordino‐Yang in this important article serve as a salutary reminder to educators that there are multiple pathways to the achievement of many developmental goals and that the educator’s role is to support the student’s optimal trajectory rather than imposing a normative trajectory.
Brains and the Dynamics of “Wants” and “Cans” in Learning
Authors: Van Geert Paul , Steenbeek Henderien
Published: May 2008

ABSTRACT— Immordino‐Yang’s description of the unexpected recovery of 2 boys with severe brain trauma is an example of the interplay between the plasticity of the brain and the plasticity of the context. It highlights the dynamics of “wants and cans” and the specific role of motivation in this dynamic. As an example of how this dynamic can evolve in different directions, we focus on learning trajectories of children with developmental psychopathology using a model of the process of social interaction to explain the interplay between behavior and performance on short‐term and long‐term timescales. The idea is that the flexibility of the short‐term process allows for a particular quality of teaching and learning and helps explain highly unexpected developmental trajectories such as those described by Immordino‐Yang (2008). The explanation of the long‐term outcomes of the educational process lies not in the determinism of the (dysfunctional) brain but in the positive characteristics of interacting creative minds.
The Smoke Around Mirror Neurons: Goals as Sociocultural and Emotional Organizers of Perception and Action in Learning
Authors: Immordino‐Yang Mary Helen
Published: May 2008

ABSTRACT— From the pragmatists to the neo‐Piagetians, development has been understood to involve cycles of perception and action—the internalization of interactions with the world and the construction of skills for acting in the world. From a neurobiological standpoint, new evidence suggests that neural activities related to action and perception converge in the brain in high‐level sensory association and motor planning areas that have been described as “mirror neuron areas.” However, the term “mirroring” can be misleading for educators and neuroscientists alike, as it suggests a direct and largely passive internal reflection of another person’s goals and actions into one’s own brain. Building from my colleagues’ thoughts on my earlier study of two hemispherectomized boys (M. H. Immordino‐Yang, 2007, pp. 66–83; see commentaries, this issue), in this response to commentaries, I suggest a model in which the internalization of another’s goals and actions happens in a culturally modulated dynamic interaction between minds and is grounded in the neuropsychological strengths and weaknesses of the learner. In this approach, learners capitalize on their strengths and preferences to internalize and construct representations of problem domains, a process that is organized by the “smoke around the mirrors”—sociocultural and emotional factors.
Current Genetic Discoveries and Education: Strengths, Opportunities, and Limitations
Authors: Bates Timothy C.
Published: May 2008

ABSTRACT— This article notes that many key positive developments in education originated in research on the structure and genetics of abilities, providing primary evidence for ability in disadvantaged groups and playing a critical role in demonstrating the existence of developmental learning disorders and effective interventions. It is argued that new work in genetics offers similar hope, but that widely held beliefs about genetic equipotentiality and brain plasticity act as roadblocks to research improving educational outcomes. It is suggested that rebuilding the collaborative links between educationalists and psychometric and genetic research that functioned so effectively in the early development of universal education can again underpin improved educational outcomes.
Is There a Role for Executive Functions in the Development of Mathematics Ability?
Authors: Blair Clancy , Knipe Hilary , Gamson David
Published: May 2008

ABSTRACT— This article examines the role of working memory, attention shifting, and inhibitory control executive cognitive functions in the development of mathematics knowledge and ability in children. It suggests that an examination of the executive cognitive demand of mathematical thinking can complement procedural and conceptual knowledge‐based approaches to understanding the ways in which children become proficient in mathematics. Task analysis indicates that executive cognitive functions likely operate in concert with procedural and conceptual knowledge and in some instances might act as a unique influence on mathematics problem‐solving ability. It is concluded that consideration of the executive cognitive demand of mathematics can contribute to research on best practices in mathematics education.
Cycles of Research and Application in Education: Learning Pathways for Energy Concepts
Authors: Dawson Theo L. , Stein Zachary
Published: May 2008

ABSTRACT— We begin this article by situating a methodology called developmental maieutics in the emerging field of mind, brain, and education. Then, we describe aspects of a project in which we collaborated with a group of physical science teachers to design developmentally informed activities and assessments for a unit on energy. Pen‐and‐paper assessments, called teasers, were employed, along with interviews, to study how students learned about the physics of energy. Results were used to describe students’ learning pathways and to design a scoring rubric for teacher use. We hypothesized that (a) teasers, by themselves, could be used effectively to evaluate the developmental level of students’ reasoning about energy and (b) teachers could employ the scoring rubric with minimal instruction. Encouraged by our findings, we went on to create a freely available online version of the energy teaser, including a new rubric designed to improve the accuracy with which teachers can assess the developmental level of students’ energy conceptions.
Dopamine Receptor D2 Polymorphism Moderates the Effect of Parental Education on Adolescents’ School Performance
Authors: Keltikangas‐Järvinen Liisa , Pullmann Helle , Pulkki‐Råback Laura , Alatupa Saija , Lipsanen Jari , Airla Nina , Lehtimäki Terho
Published: May 2008

ABSTRACT— High parental socioeconomic status is known to have a positive effect on students’ academic achievement. We examined whether variation in the dopamine receptor gene (DRD2 polymorphism, rs 1800497) modifies the association between parental educational level and school performance in adolescence. The participants were a randomly selected subsample of individuals participating in the Cardiovascular Risk in Young Finns study (921 girls and 742 boys) aged 12–15 years at the time school performance was assessed. The genotyping was performed using TaqMan 5′'‐nuclease assay. A significant interaction was found between childhood parental educational level and students’ DRD2 polymorphism on academic achievement after adjustment for age, gender, household income, parental occupation, maternal nurturance, hyperactivity, and sociability. Parental educational level was significantly positively associated with school achievement in the A2/A2 (n = 1,061) and the A1/A2 (n = 529) genotype groups, but was negative and statistically insignificant in participants carrying the A1/A1 (n = 73) genotype. It is concluded that the extent to which parental education status affects an individual’s academic achievement may be dependent on the individual’s genetic constitution. The findings may increase an acceptance of genetic influence in education, and, consequently, may increase accurateness of educational interventions.
Development of a three‐dimensionally movable phantom system for dosimetric verifications
Authors: Nakayama Hiroshi , Mizowaki Takashi , Narita Yuichiro , Kawada Noriyuki , Takahashi Kunio , Mihara Kazumasa , Hiraoka Masahiro
Published: May 2008

The authors developed a three‐dimensionally movable phantom system (3D movable phantom system) which can reproduce three‐dimensional movements to experimentally verify the impact of radiotherapy treatment‐related movements on dose distribution. The phantom system consists of three integrated components: a three‐dimensional driving mechanism (3D driving mechanism), computer control system, and phantoms for film dosimetry. The 3D driving mechanism is a quintessential part of this system. It is composed of three linear‐motion tables (single‐axis robots) which are joined orthogonally to each other. This mechanism has a motion range of 100 mm, with a maximum velocity of 200 mm/s in each dimension, and 3D motion ability of arbitrary patterns. These attributes are sufficient to reproduce almost all organ movements. The positional accuracy of this 3D movable phantom system in a state of geostationary is less than 0.1 mm. The maximum error in terms of the absolute position on movement was 0.56 mm. The positional reappearance error on movement was up to 0.23 mm. The observed fluctuation of time was 0.012 s in the cycle of 4.5 s of oscillation. These results suggested that the 3D movable phantom system exhibited a sufficient level of accuracy in terms of geometry and timing to reproduce interfractional organ movement or setup errors in order to assess the influence of these errors on high‐precision radiotherapy such as stereotactic irradiation and intensity‐modulated radiotherapy. In addition, the authors 3D movable phantom system will also be useful in evaluating the adequacy and efficacy of new treatment techniques such as gating or tracking radiotherapy.
Structure and Dynamics of Earth's Lower Mantle
Authors: Garnero Edward J. , McNamara Allen K.
Published: May 2008

Processes within the lowest several hundred kilometers of Earth's rocky mantle play a critical role in the evolution of the planet. Understanding Earth's lower mantle requires putting recent seismic and mineral physics discoveries into a self-consistent, geodynamically feasible context. Two nearly antipodal large low-shear-velocity provinces in the deep mantle likely represent chemically distinct and denser material. High-resolution seismological studies have revealed laterally varying seismic velocity discontinuities in the deepest few hundred kilometers, consistent with a phase transition from perovskite to post-perovskite. In the deepest tens of kilometers of the mantle, isolated pockets of ultralow seismic velocities may denote Earth's deepest magma chamber.
Comment on "Long-Lived Giant Number Fluctuations in a Swarming Granular Nematic"
Authors: Aranson I. S. , Snezhko A. , Olafsen J. S. , Urbach J. S.
Published: May 2008

Narayan
et al.
(Reports, 6 July 2007, p. 105) reported giant number fluctuations attributed to curvature-driven active currents specific for nonequilibrium nematic systems. We present data demonstrating that similar results can be found in systems of spherical particles due either to inelastic clustering or persistent density inhomogeneity, suggesting two alternative explanations for their results.
Expanding Oxygen-Minimum Zones in the Tropical Oceans
Authors: Stramma Lothar , Johnson Gregory C. , Sprintall Janet , Mohrholz Volker
Published: May 2008

Oxygen-poor waters occupy large volumes of the intermediate-depth eastern tropical oceans. Oxygen-poor conditions have far-reaching impacts on ecosystems because important mobile macroorganisms avoid or cannot survive in hypoxic zones. Climate models predict declines in oceanic dissolved oxygen produced by global warming. We constructed 50-year time series of dissolved-oxygen concentration for select tropical oceanic regions by augmenting a historical database with recent measurements. These time series reveal vertical expansion of the intermediate-depth low-oxygen zones in the eastern tropical Atlantic and the equatorial Pacific during the past 50 years. The oxygen decrease in the 300- to 700-m layer is 0.09 to 0.34 micromoles per kilogram per year. Reduced oxygen levels may have dramatic consequences for ecosystems and coastal economies.
Coherent Control of Decoherence
Authors: Branderhorst Matthijs P. A. , Londero Pablo , Wasylczyk Piotr , Brif Constantin , Kosut Robert L. , Rabitz Herschel , Walmsley Ian A.
Published: May 2008

Manipulation of quantum interference requires that the system under control remains coherent, avoiding (or at least postponing) the phase randomization that can ensue from coupling to an uncontrolled environment. We show that closed-loop coherent control can be used to mitigate the rate of quantum dephasing in a gas-phase ensemble of potassium dimers (K
2
), which acts as a model system for testing the general concepts of controlling decoherence. Specifically, we adaptively shaped the light pulse used to prepare a vibrational wave packet in electronically excited K
2
, with the amplitude of quantum beats in the fluorescence signal used as an easily measured surrogate for the purpose of optimizing coherence. The optimal pulse increased the beat amplitude from below the noise level to well above it, and thereby increased the coherence life time as compared with the beats produced by a transform-limited pulse. Closed-loop methods can thus effectively identify states that are robust against dephasing without any previous information about the system-environment interaction.
Response to Comment on "Long-Lived Giant Number Fluctuations in a Swarming Granular Nematic"
Authors: Narayan V. , Ramaswamy S. , Menon N.
Published: May 2008

On the basis of experiments using monolayers of spherical grains, Aranson et al. suggest that the giant number fluctuations we observed in active granular rods may be explained by static inhomogeneity or inelastic clustering. We refute these alternative explanations and underline the evidence that the fluctuations originate in nematic ordering.
Practical Synthesis of Prostratin, DPP, and Their Analogs, Adjuvant Leads Against Latent HIV
Authors: Wender Paul A. , Kee Jung-Min , Warrington Jeffrey M.
Published: May 2008

Although antiretroviral therapies have been effective in decreasing active viral loads in AIDS patients, the persistence of latent viral reservoirs prevents eradication of the virus. Prostratin and DPP (12-deoxyphorbol-13-phenylacetate) activate the latent virus and thus represent promising adjuvants for antiviral therapy. Their limited supply and the challenges of accessing related structures have, however, impeded therapeutic development and the search for clinically superior analogs. Here we report a practical synthesis of prostratin and DPP starting from phorbol or crotophorbolone, agents readily available from renewable sources, including a biodiesel candidate. This synthesis reliably supplies gram quantities of the therapeutically promising natural products, hitherto available only in low and variable amounts from natural sources, and opens access to a variety of new analogs.
Fire-Derived Charcoal Causes Loss of Forest Humus
Authors: Wardle David A. , Nilsson Marie-Charlotte , Zackrisson Olle
Published: May 2008

Fire is a global driver of carbon storage and converts a substantial proportion of plant biomass to black carbon (for example, charcoal), which remains in the soil for thousands of years. Black carbon is therefore often proposed as an important long-term sink of soil carbon. We ran a 10-year experiment in each of three boreal forest stands to show that fire-derived charcoal promotes loss of forest humus and that this is associated with enhancement of microbial activity by charcoal. This result shows that charcoal-induced losses of belowground carbon in forests can partially offset the benefits of charcoal as a long-term carbon sink.
In Vivo Imaging of Membrane-Associated Glycans in Developing Zebrafish
Authors: Laughlin Scott T. , Baskin Jeremy M. , Amacher Sharon L. , Bertozzi Carolyn R.
Published: May 2008

Glycans are attractive targets for molecular imaging but have been inaccessible because of their incompatibility with genetically encoded reporters. We demonstrated the noninvasive imaging of glycans in live developing zebrafish, using a chemical reporter strategy. Zebrafish embryos were treated with an unnatural sugar to metabolically label their cell-surface glycans with azides. Subsequently, the embryos were reacted with fluorophore conjugates by means of copper-free click chemistry, enabling the visualization of glycans in vivo at subcellular resolution during development. At 60 hours after fertilization, we observed an increase in de novo glycan biosynthesis in the jaw region, pectoral fins, and olfactory organs. Using a multicolor detection strategy, we performed a spatiotemporal analysis of glycan expression and trafficking and identified patterns that would be undetectable with conventional molecular imaging approaches.
A Specialized Forebrain Circuit for Vocal Babbling in the Juvenile Songbird
Authors: Aronov Dmitriy , Andalman Aaron S. , Fee Michale S.
Published: May 2008

Young animals engage in variable exploratory behaviors essential for the development of neural circuitry and adult motor control, yet the neural basis of these behaviors is largely unknown. Juvenile songbirds produce subsong—a succession of primitive vocalizations akin to human babbling. We found that subsong production in zebra finches does not require HVC (high vocal center), a key premotor area for singing in adult birds, but does require LMAN (lateral magnocellular nucleus of the nidopallium), a forebrain nucleus involved in learning but not in adult singing. During babbling, neurons in LMAN exhibited premotor correlations to vocal output on a fast time scale. Thus, juvenile singing is driven by a circuit distinct from that which produces the adult behavior—a separation possibly general to other developing motor systems.
Strong Interactions in Multimode Random Lasers
Authors: Türeci Hakan E. , Ge Li , Rotter Stefan , Stone A. Douglas
Published: May 2008

Unlike conventional lasers, diffusive random lasers (DRLs) have no resonator to trap light and no high-Q resonances to support lasing. Because of this lack of sharp resonances, the DRL has presented a challenge to conventional laser theory. We present a theory able to treat the DRL rigorously and provide results on the lasing spectra, internal fields, and output intensities of DRLs. Typically DRLs are highly multimode lasers, emitting light at a number of wavelengths. We show that the modal interactions through the gain medium in such lasers are extremely strong and lead to a uniformly spaced frequency spectrum, in agreement with recent experimental observations.
Asymmetric Tethering of Flat and Curved Lipid Membranes by a Golgin
Authors: Drin Guillaume , Morello Vincent , Casella Jean-François , Gounon Pierre , Antonny Bruno
Published: May 2008

Golgins, long stringlike proteins, tether cisternae and transport vesicles at the Golgi apparatus. We examined the attachment of golgin GMAP-210 to lipid membranes. GMAP-210 connected highly curved liposomes to flatter ones. This asymmetric tethering relied on motifs that sensed membrane curvature both in the N terminus of GMAP-210 and in ArfGAP1, which controlled the interaction of the C terminus of GMAP-210 with the small guanine nucleotide–binding protein Arf1. Because membrane curvature constantly changes during vesicular trafficking, this mode of tethering suggests a way to maintain the Golgi architecture without compromising membrane flow.
A Haptoglobin-Hemoglobin Receptor Conveys Innate Immunity to
Trypanosoma brucei
in Humans
Authors: Vanhollebeke Benoit , De Muylder Géraldine , Nielsen Marianne J. , Pays Annette , Tebabi Patricia , Dieu Marc , Raes Martine , Moestrup Soren K. , Pays Etienne
Published: May 2008

The protozoan parasite
Trypanosoma brucei
is lysed by apolipoprotein L-I, a component of human high-density lipoprotein (HDL) particles that are also characterized by the presence of haptoglobin-related protein. We report that this process is mediated by a parasite glycoprotein receptor, which binds the haptoglobin-hemoglobin complex with high affinity for the uptake and incorporation of heme into intracellular hemoproteins. In mice, this receptor was required for optimal parasite growth and the resistance of parasites to the oxidative burst by host macrophages. In humans, the trypanosome receptor also recognized the complex between hemoglobin and haptoglobin-related protein, which explains its ability to capture trypanolytic HDLs. Thus, in humans the presence of haptoglobin-related protein has diverted the function of the trypanosome haptoglobin-hemoglobin receptor to elicit innate host immunity against the parasite.
On Deciding How to Do unto Others
Authors: Ak Prashanth
Published: May 2008

The Neuroscience of Fair Play
. Why We (Usually) Follow the Golden Rule.
By Donald W. Pfaff
. Dana Press, New York, 2007. 248 pp. $20.95. ISBN 9781932594270.

Rejecting the idea of signaling circuits devoted to ethics, the author discusses neural and genetic mechanisms that may underlie the behavior of treating others as one wishes to be treated
Rethinking Folk Psychology
Authors: Myin Erik
Published: May 2008

Folk Psychological Narratives
. The Sociocultural Basis of Understanding Reasons.
By Daniel D. Hutto
. MIT Press, Cambridge, MA, 2008. 367 pp. $38, £24.95. ISBN 9780262083676.

The author argues for a "narrative practice" alternative to "theory of mind" explanations of the human capacity for understanding other persons in terms of their beliefs and desires.
Predictive Models of Benthic Macroinvertebrate Density for Use in Instream Flow Studies and Regulated Flow Management
Authors: Gore James A. , Judy Jr. Robert D.
Published: May 2008

As an adjunct to the U.S. Fish and Wildlife Service incremental method for determining habitat suitability for sport fish species at various discharge levels, we propose a similar method for determining optimum conditions for stream macroinvertebrates that stresses predictions of density maxima and flow predictions for maintenance of suitable lotic habitat.The curve fitting equations of the computer simulation showed high reliability in predicting physical habitat tolerances of selected aquatic insects. An example using Nectopsyche lahontonensis is presented.The new predictive model, by exponential polynomial analysis, answers criticisms of earlier models which do not include the dependence of velocity and depth in stream channel hydraulics. The added cross-product term in the model altered the predicted peak responses (density) with random changes in depth and velocity. Although the new model improves the predictions, its effectiveness in stream management has yet to be tested.Key words: habitat suitability, macroinvertebrates, exponential polynomial analysis, flow management, Nectopsyche lahontonensis
Distribution tissulaire du cadmium chez Meganyctiphanes norvegica (Euphausiacée): état naturel et accumulationexpérimentale de formes solubles
Authors: Poirier Louis , Cossa Daniel
Published: May 2008

In the tissues of Meganyctiphanes norvegica collected from their natural environment, 57% of body cadmium was in soluble compounds, principally bound with proteins (mol wt ≥ 25 000). A cadmium-binding protein, with a molecular weight of ~ 21 000, was induced during laboratory contamination experiments. However, a large portion of cadmium is adsorbed onto exoskeleton. The association of the metal with chitin and its removal by molting may constitute a defence process particular to crustaceans.
Dynamics and Environmental Effects of Ice in the Cumberland Basin of the Bay of Fundy
Authors: Gordon Jr. Donald C. , Desplanque Con
Published: May 2008

Ice occurs in the upper reaches of the Bay of Fundy from December to April and conditions are influenced by the macrotides characteristic of the area. Drift ice forms on the seawater surface and because of almost constant movement in tidal currents is composed of small, rounded pieces. Shorefast ice develops from the stranding of drift ice between the neap and spring high water levels. Drift ice can also strand during ebb tide on intertidal salt marshes and mudflats which together comprise two-thirds of the Cumberland Basin area. Intertidal sediments can freeze to form a frozen crust, and sheet ice can form where salinity and tidal energy are low. Shorefast ice can significantly reduce the cross-sectional area of tidal rivers and encourage flooding. Stranded drift ice can import sediment and export plant debris from salt marshes. Mudflats are heavily scoured by ice all winter which causes erosion and mortality of benthic organisms. Construction of a tidal power project would change ice properties considerably.
Hymenolepis diminuta: uptake of 5-hydroxytryptamine (serotonin), glucose, and changes in worm glycogen levels
Authors: Cyr Denis , Gruner S. , Mettrick D. F.
Published: May 2008

The effects of 5-hydroxytryptamine (5-HT) and its specific antagonist, methylsergide hydrogenmaleinate, on in vitro glucose uptake by Hymenolepis diminuta were followed for up to 60 min. Maximum stimulation of glucose uptake occurred with 0.5 mM 5-HT. With the addition of 10 mM methysergide (MET) glucose uptake decreased by 68%. Glucose uptake was greatest in the anterior, immature region of the worm strobila, and diminished through the middle to the posterior gravid portion of the strobila. 5-HT significantly increased glucose uptake in all three regions. The addition of 3 mM MET eliminated the stimulatory action of 5-HT on glucose uptake in the anterior and middle regions of the strobila; 10 mM MET significantly reduced glucose uptake in all three regions of the worm. The presence of 0.5 mM 5-HT both stimulated glucose uptake and decreased worm glycogen levels in all three regions of the strobila. The further addition of 0.5 mM MET did not affect the reduced glycogen levels. 5-HT uptake by H. diminuta was over 60% higher in the anterior segment of the strobila compared with uptake in the middle and posterior segments. The addition of 3 mM MET significantly decreased 5-HT uptake in the anterior and middle regions of the strobila; 10 mM MET decreased 5-HT uptake in all three regions. The regional differences in 5-HT and glucose uptake by H. diminuta suggest that the tryptaminergic receptors in the strobila are not equally distributed along the length of the worm. The effects of MET on glucose and 5-HT uptake are in part accountable through its action in blocking 5-HT receptors.
Life in Pre-Cambrian and early Cambrian times
Authors: Cowie John Watson
Published: May 2008

Physical and chemical conditions which could have favoured the origin of life on Earth are briefly discussed, together with the evidence of the geological record. Free oxygen may be of critical importance as a factor in the early evolution of life. Recent studies of the occurrence of biogenic materials and the micropalaeontology of ancient rocks have led to striking advances in knowledge of Pre-Cambrian life. Plants and protistids are the oldest known fossils. Pre-Cambrian fossil protozoans and most metazoans are the subject of dispute. The remarkable fauna from Ediacara is partly metazoan, but the age may be Cambrian or Pre-Cambrian. Aspects of the problem of the base of the Cambrian System are discussed and the earliest Cambrian taxa are listed. Selected theories which attempt to explain the manner of appearance and character of the early Cambrian fauna are reviewed in a brief conspectus.
Fluctuations in the evolution of Palaeozoic intertebrates
Authors: House Michael Robert
Published: May 2008

The problem of interpreting faunal fluctuations is reviewed and it is stressed that numerical abundance cannot be assessed, and morphological diversity only by comparing taxa or the subjective views of specialists. Comparisons at generic and higher taxon levels are made for the more common Palaeozoic fossil groups for appearance of new and extinction of old stocks. The striking diversification (and often appearance) of many groups with calcareoushard parts during the Ordovician is stressed and related to evidence for particularly widespread shallow seas at that time. In detail, groups do not show precise time agreement in their later evolutionary ‘bursts’, but significant periods seem to be during the early and mid-Devonian and the early Carboniferous, but these are at taxon grades lower than the Ordovician diversification. For extinctions it is often possible to separate intrataxal, presumably competitive, extinctions during the rapid rise of a group, from extinctions which appear to affect unrelated stocks. Significant periods for the latter are around the mid- and late Devonian and the mid- and late Carboniferous. These extinctions occur
pari passu
, rather than as single catastrophic events. Possible long-continued palaeogeographical causes are considered.
Changes in terrestrial vertebrate faunas during the Mesozoic
Authors: Cox C. B.
Published: May 2008

The precise time-range of any terrestrial group is difficult to establish, due to the uncertainties of preservation and discovery and due to the difficulty of ascertaining the relative ages of faunas from different areas. Differences between such faunas may be due to ecological and zoogeographical factors as well as to age differences. Even when a relative time-sequence has been established, it is difficult to correlate this with the standard section for the period; this is particularly true for the Triassic faunas.

As seen in the South African record, the climate became progressively hotter and drier from the Carboniferous Dwyka glaciation until the deserts of the Upper Triassic. The earliest Triassic fauna is a swamp fauna which still included elements of most of the more conservative, synapsid reptiles. During the remainder of the Triassic, these synapsids were gradually replaced by the evolving diapsids. The more primitive members of the Diapsida were themselves replaced in the Jurassic by more progressive members of the group.

The earliest mammals, those of the Triassic and Jurassic, were probably homoiothermal though not viviparous. None larger than a cat is known until immediately after the disappearance of the dinosaurs. The reasons for this apparent inability of somewhat larger (e.g. pig-sized) mammals to co-exist with the dinosaurs are not obvious.
Some Cretaceous-Tertiary marine faunal changes
Authors: Hancock John Michael
Published: May 2008

The progressive disappearance of ammonites and belemnites is described in some detail. The Tertiary range of some of the common Cretaceous echinoids is discussed. References are given for the planktonic foraminifera. It is concluded that the late-Cretaceous disappearances were not simultaneous, were preceded by geographical contraction, and cannot be explained catastrophically.
Biochemical evolution and the fossil record
Authors: Tarlo Lambert Beverly Halstead
Published: May 2008

From the sequences of amino-acids in protein molecules and their substitutions in different parts of the molecule, it can be shown how, for example, the four polypeptide chains of the respiratory pigment haemoglobin can be derived from one another, and ultimately from myoglobin. Zuckerkandl & Pauling have estimated the times at which the four chains found in human haemoglobin are likely to have originated—the alpha chain 650 m.y. ago, gamma 380 m.y., beta 150 m.y. and delta 35 m.y. These dates coincide exactly with the first records of crossopterygian fish (380 m.y.) and the anthropoids (35 m.y.) and approximately with the placental mammals (135 m.y.). However, this approach can only be vindicated if it can be applied to proteins actually preserved in the fossil record. The only important protein so preserved is collagen and there are considerable problems still to be overcome in its study (viz. the differential breakdown of the amino-acids with the consequent alteration of the molecule, and also contamination from amino-acids derived from organic debris in the surrounding sediments). With the aid of the ‘Technicon automatic Amino-Acid Analyzer’ it is hoped to eventually resolve these problems. If an evolutionary picture can be built up for collagen, on the lines of that already begun for haemoglobin, and if in the meantine the exact fate of collagen in geological time can be established, it may eventually be possible to test theories of biochemical evolution by direct reference to fossil proteins.
Fossil birds and their adaptive radiation
Authors: Fisher James
Published: May 2008

The history of the systematic listing of fossilbird taxa is briefly reviewed, and the radiation of avian palaeospecies discussed. Their stratigraphical succession in the Mesozoic and Cainozoic is then presented in some detail.
Numerical analysis of
The Fossil Record
Authors: Cutbill J. L. , Funnell B. M.
Published: May 2008

A numerical analysis has been carried out based on the ranges of taxa as shown in Part II of
The Fossil Record
. The numbers of first occurrences, last occurrences and totals have been calculated for groups of related taxa for each stratigraphical sub-division. Relative and net changes across all sub-division boundaries have also been calculated. Results for selected groupings are presented in the form of combined histograms and graphs. Smoothing techniques have been applied to some results, and some other numerical measures calculated.
Some principles governing interpretation of structure in the Rocky Mountain orogenic belt
Authors: Fox F. G.
Published: May 2008

Any interpretation of the structure of an orogenic belt must be based upon detailed geological maps of the belt or large areas of it, together with sufficient stratigraphical data for sections to be constructed projecting the structure observable at the surface to depth.

In making such structural interpretations a number of principles and ‘rules’ should be observed; some of these are outlined and their application illustrated with selected structural sections.
The measurement of strain and displacement in orogenic belts
Authors: Ramsay J. G.
Published: May 2008

Many of the premises that have been used in evaluating the crustal shortening across orogenic belts are open to question. Past estimates of displacement have often depended upon the validity of some preconceived tectonic hypothesis and its mechanical feasibility.

Displacements describe the changes in position of particles in space, and can be defined in three dimensions by a set of three equations. Displacement leads to three main effects: (1) body translation, (2) body rotation, (3) strain. The inter-relationships and properties of these features are discussed to determine which features the geologist can measure in naturally deformed rocks.

Absolute values for the amount of displacement are impossible to determine. Displacement differences between different localities are related to crustal shortening and under special circumstances may be computed with precision. Techniques for determining displacement difference employ two methods, (1) removal of the effects of strain through the deformed zone, and (2) resection of once continuous linear features in the foreland and hinterland. These have been applied successfully in parts of deformed zones but their application to a complete orogenic belt is for the future.
The construction of sections in areas of highly deformed rocks
Authors: Phillips W. E. A. , Byrne J. G.
Published: May 2008

The construction of sections is essential to the analysis of rock bodies. Qualitative sketch sections and block diagrams help to unravel stratigraphy within complex polyphase structures. They also provide a method of summarizing information. Present methods of constructing quantitative sections, being only applicable to parallel folds, are of limited value.

A new method of constructing quantitative sections is described. In this the rate of change of fold shape with depth is measured, rather than assumed as previously. On profile sections of folds, this rate can be described by constructing stratification isogonal lines joining points of constant dip. Their orientation can be used to classify folds. In cylindrical folds, such isogonal lines lie upon stratification isogonal surfaces, the location of which can be found from structural maps, either by graphic construction, or by using a digitizer and an electronic computer. This information is used to construct, on any section plane, stratification isogonal lines which sub-divide the section into dip zones, and provide control for constructing sections to the depth of topographic or structural relief.

Applications of the method to recognizing faults and palaeoslopes, and to classifying folds and constructing sections in areas of noncylindrical and polyphase deformation, are described.

These methods make fuller use of structural data and provide quantitative descriptions of folds. This could lead to the definition of structural facies and to a better understanding of displacements within the continental crust.
The palaeomagnetic evidence of displacements within continents
Authors: Tarling D. H.
Published: May 2008

There are many problems in the utilization of palaeomagnetism in tectonic studies. The major factor is the ignorance of the mechanism of magnetization of sediments, but serious problems may also be encountered in areas subjected to tectonic disturbances. Despite these difficulties, there are many examples of palaeomagnetic techniques applied to tectonic problems within single continents and examples are described from the Appalachians, the Rocky Mountains, the European Alpine system, the Near and Far East. Although the precision of the current palaeomagnetic data is rather low, it is quite clear that these techniques have a very high potential in areas which can be subjected to detailed study in the field and laboratory.
Interpretation of stratigraphical ages in orogenic belts
Authors: Harland W. B.
Published: May 2008

This paper discusses some aspects of the dating of specified orogenic events, in terms of a stratigraphical scale, by various methods of correlation.

A standard stratigraphical scale is the common reference to which various data (structural, palaeontological, isotopic, etc.) and events interpreted from them are correlated. Lists of tectonic phases express age estimates of particular tectonic events and cannot usefully substitute for a standard scale.

Some datable elements in orogeny are defined. The direct relation between an orogenic event and a stratigraphical scale, as determined in different ways, yields an age which is limited in precision by distinct components of indeterminacy and uncertainty.

Correlation depends partly on diastrophic gradient which distinguishes the effects of tectonic events that are confined to the immediate neighbourhood from those at greater distance; few events have global effects (e.g., eustatic change). Correlation is generally effected, however, by relatively independent events, (e.g., biological, evolutionary, nuclear decay, climatic, magnetic reversals, etc.).

The primary purpose of dating orogenic events is to enquire into the distribution of earth movements in space and time. The results can be given in a number of ways (e.g., tectonograms, palaeotectonic and palinspastic maps, kinematic tectonic realms). Because the Earth’s surface is a closed system a total synoptic stratigraphical study of many aspects of the time, direction and magnitude of movement becomes possible and is aided by new procedures of co-ordinated research, compilation, and automatic processing of data.
Interpretation of isotopic ages in orogenic belts
Authors: Brown P. E. , Miller J. A.
Published: May 2008

K-Ar and Rb-Sr methods of age-determination are the most widely applied; geological interpretation of ages so obtained is in some cases facilitated by U-Pb ages on zircons. On a broad continental scale isotopic ages have been used to delineate the time-span of evolution of structural provinces; the spread of ages so obtained is as great as 800 m.y. Within such a spread, interpretation of isotopic ages is discussed with reference to the orogenic cycle; orogenic belts may be multicyclic and involve rocks formed in a previous cycle, and there may also be repetition of phases within a cycle. The interpretation of ages obtained on rocks developed in the syn-, late- and post-orogenic phases of the orogenic cycle is considered. The question of what is being dated with respect to rocks formed in syn- and late-orogenic plutonism is considered in terms of multi-phase events and of cooling of the orogenic belt to temperatures at which radiogenic daughter products become frozen in; post-tectonic igneous activity may provide valuable datum points in the orogenic cycle. It is emphasized that full geological information is essential to any interpretation of detail within the spread of ages obtained from an orogenic cycle.
A new approach to radio-isotopic dating in orogenic belts
Authors: Fitch F. J. , Miller J. A. , Mitchell J. G.
Published: May 2008

The theory of conventional K-Ar dating and the opposed ‘overprinting’ and ‘slow-cooling’ interpretations of radio metric age sequences in orogenic belts are examined briefly. A new K-Ar age-spectrum method is described which enables intermediate ages obtained from partially overprinted rocks and minerals to be unmixed. Under ideal conditions one or both of the component ages can be determined. Applications of the K-Ar age-spectrum method to a number of dating problems in the British Caledonides are reported as examples of the importance of the new method in orogenic studies. In particular, there is a discussion of the geochronology of the Moine and Dalradian Series in Scotland and the Tanygriseau microgranite in North Wales. Finally, there is a discussion of the possible implications of the new data for orogenic theory.
Orogenic belts and their parts
Authors: Rast N.
Published: May 2008

Geological tectonic literature is at present confused. For instance, in the existing literature the terms
geosyncline
and
orogenic belt
are often used almost synonymously. This usage is misleading and obscures the fact—demonstrated with respect to several orogenic belts—that orogenic belts are structural units of a larger size than geosynclines and may involve a series of geosynclinal furrows. Consequently in discussing geotectonic concepts a proper nomenclature of orogenic belts and their divisions has to be employed; certain proposals are therefore made.

It is also significant that, at least within Phanerozoic time, orogenic belts originated repeatedly in the same sections of continental crust. Such relationships are indicated by both geological and geochronological investigations. The Caledonian belt of the British Isles, for instance, is divided into several parts each affected by separate orogenic movements. The boundaries between these parts are often delineated by major fault lineaments. Else-where such deep fundamental faults are held to be important in the siting and evolution of orogenic belts.
Rates of change within orogenic belts
Authors: Sutton J.
Published: May 2008

The following types of change are considered: changes in the arrangement of orogenic belts since late Pre-Cambrian times, in particular their reduction in number: rates of vertical and horizontal displacement are given and bring out the contrast between vertical displacement whose rate falls off with time, and horizontal movement which may continue for many hundreds of million years at a few centimetres per annum. The paper ends with a discussion of the migration of plutonically active regions.
The deep structure of orogenic belts—the root problem
Authors: Oxburgh E. R.
Published: May 2008

Differences in physical properties between orogenic areas and adjacent inactive regions extend to depths of at least 200, and possibly 400 km, into the upper mantle; these differences are evident from the anomalous travel-times of Love waves traversing orogenic regions. At shallow depths, near the crust-mantle interface, such differences may be investigated by means of seismic refraction and some recent studies in the Alps and the United States are reviewed; it appears that many active orogenic areas are characterized by (1) greater than average crustal thicknesses, (2) higher than average compressional wave velocities at the base of the crust, (3) unusually low velocity contrasts at the Mohorovičić discontinuity and (4) higher temperatures in the lower crust and upper mantle than at equivalent depths in adjacent inactive areas. The magnitudes of these effects are such that the lower crust in orogenic areas must differ, either in phase assemblage or in chemical composition, from the crust in adjacent areas. If the former is the case, the orogenic lower crust could be of intermediate or mafic composition in the granulite facies of regional metamorphism; in inactive regions the same chemical composition could be expressed by hydrous mineral assemblages, characterized by lower velocites and densities. This model is compatible with an origin for the orogenic root by crustal shortening. Alternatively, if the high velocities of the lower orogenic crust reflect differences in bulk chemical composition, this could occur through the addition of mantle-derived magmas as part of the orogenic process; estimates of the volume of such additions necessary to give the observed seismic velocities show that they are comparable with the apparent crustal thickening; this model is incompatible with significant amounts of crustal shortening but is compatible with either no over-all change in horizontal crustal dimensions, or with small amounts of crustal extension. The alternative models are discussed.