bluuebunny/crossref_metadata_2025_split huggingface dataset:
Potentialities, uncertainties and complexities in the response of coral reefs to future sea‐level rise
Authors: Spencer T. 
Published: February 2007

AbstractCoral islands formed of largely unconsolidated sands only a few metres above sea level are thought to be particularly vulnerable to sea‐level rise consequent upon global warming. However, scenarios which predict catastrophic flooding and loss of island area need reassessment, particularly in the light of the continued downwards revision of projected rates of future sea‐level rise. Revised questions concern the interactions between reef growth and sea‐level change, biophysical constraints on coral growth, and the importance to reef systems of potential changes in the magnitude, frequency and location of tropical cyclones and hurricanes. It is clear that most reefs have the growth potential to meet even the highest of future sea‐level rise scenarios, but too little is known about physiological and physical constraints to reef growth to adequately evaluate the importance of these two factors in constraining this potential at the present time. Future sea‐level rise in the tropical oceans, and coral reef responses, will take place against a backdrop of inter‐regional differences in Holocene sea levels, resulting from the varying interaction of eustatic and hydro‐isostatic processes. These differences have generated varying constraints on the development of modern reefs and varying inherited topographies upon which future sea‐level changes will be superimposed. These controls are particularly important in assessing differences in vulnerability to future sea‐level rise for reef islands in the Pacific Ocean and the Caribbean Sea.
Rock‐weathering by the lichenLecidea auriculatain an arctic alpine environment
Authors: McCarroll Danny , Viles Heather 
Published: February 2007

AbstractScanning electron microscopy reveals thatLecidea auriculatapenetrates rock surfaces, detaching, incorporating and expelling flakes of rock. Measurements on an age sequence of moraine ridges illustrate changes in the extent and intensity of weathering over time. A minimum rate of surface lowering (0·0012 mm a−1) is 25 to 50 times faster than weathering due to other processes in the same area. The spatial pattern of weathering is influenced by the narrow ecological range of the species. Surface rocks on dry, exposed sites are probably weathering much more rapidly than those in adjacent damp hollows and beneath snowpatches.
Surface stone cover on desert hillslopes; parameterizing characteristics relevant to infiltration and surface runoff
Authors: Dunkerley D. L. 
Published: February 2007

AbstractSurface stones are a common feature of desert hillslopes. They influence slope processes ranging from the interception and partitioning of rainwater to the dislodgement and transport of regolith particles. The aspects of a stone mantle which relate to these various influences are diverse, and include surface cover fraction, dimensions of the infiltration annulus, and geometric and packing effects.Analyses of the characteristics of stone cover at two study sites were made using photographic methods and are used to evaluate different means of reporting mean stone sizes. It is found that mean diameter based on weight, as conventionally employed in sieve analysis, is insensitive to important stone cover characteristics and may be influenced greatly by uncommon, large stones. Similarly, mean diameters based on count become inappropriate if large numbers of small stones dominate the calculated mean, concealing other site‐to‐site differences in stone cover. As a more appropriate parameterization of stone geometry, the use of mean diameters weighted by stone surface area and perimeter length are proposed. These weighting factors have the advantage that they relate closely to stone characteristics relevant to slope hydrology and erosion processes.
Spatial variability in soil moisture as predicted from airborne thematic mapper (ATM) data
Authors: Davidson Donald A. , Watson Alistair I. 
Published: February 2007

AbstractIn the first part of this project, the extent to which moisture content of alluvial soils could be predicted from imagery derived from an airborne thematic mapper (ATM) was investigated. From sampling done on the same day as the flight, it was found that digital numbers derived from the thermal channel (waveband 11) were strongly correlated with gravimetric moisture content. From sampling three fields of contrasting land cover, the relationship between waveband 11 values and moisture content was found to be independent of land cover type. Spatial variation in waveband 11 values and thus moisture content were related to palaeochannel patterns on the alluvial land. This was investigated by deriving variograms for long transects from each of the three investigated fields. The range and sills of the variograms are shown to express the nature and pattern of palaeochannels. By the application of such geostatistical techniques, high resolution imagery can thus be used to quantify palaeochannel characteristics on alluvial land.
Effects of soil moisture dynamics on slope failure at Hyrum Reservior, Utah
Authors: O'Neill Michael P. , McDonnell Jeffrey J. 
Published: February 2007

AbstractField observations of shoreline conditions at Hyrum Reservoir, Utah, were conducted during the summers of 1991 to 1993. A process of bluff retreat is described for a multiple‐layered bluff environment of sand and clay layers. Failure is initiated by wetting and drying of clay sediments, which produces horizontal cracks within bluff material. These cracks appear to penetrate to a depth of approximately 100‐150 mm before initiating vertical cracking in the sediments. The vertical cracks are propagated by continued drying of the surface sediment, ultimately leading to failure of the bluff material. The physical dimensions of sediment blocks succumbing to this mechanism range from a few hundred millimetres up to 3 m on a side, with a depth of approximately 100‐150 mm. The mechanism described here appears to operate optimally when the supply of subsurface moisture is abundant and nearly continuous throughout the spring and early summer. Reservoir draw‐down, large capillary fringe effects in the bluff and periodic wetting from upslope undrained hollows are the dominant moisture controls at this site. Moisture delivery to the face is strongly influenced by anisotropy of saturated hydraulic conductivity in the alternating clay and sand layers and related differences in sediment texture.
Aeolian sediment flux decay: Non‐linear behaviour on developing deflation lag surfaces
Authors: Neuman Cheryl Mckenna , Nickling W. G. 
Published: February 2007

AbstractWind tunnel simulations of the effect of non‐erodible roughness elements on sediment transport show that the flux ratio q/qs, shear velocity U*, and roughness density λ are co‐dependent variables. Initially, the sediment flux is enhanced by kinetic energy retention in relatively elastic collisions that occur at the roughness element surfaces, but at the same time, the rising surface coverage of the immobile elements reduces the probability of grain ejection. A zone of strong shearing stress develops within 0·03 to 0·04 m of the rough bed because of a relative straightening of velocity profiles which are normally convex with saltation drag. This positive influence on fluid entrainment is opposed by declining shear stress partitioned to the sand bed. Similarly, because the free stream velocity Uf is fixed while U* increases, velocity at height z and particle momentum gain from the airstream decline, leading eventually to lower numbers of particles ejected on average at each impact. When the ratio of the element basal area to frontal area σ is approximately equal to 3·5, secondary flow effects appear to become significant, so that the dimensionless aerodynamic roughness parameter Z0/h and shear stress on the exposed sand bed Ts decrease. It is at this point that grain supply to the airstream and saltation drag appear to be significantly reduced, thereby intensifying the reduction in U*. The zone of strong fluid shear near the bed dissipates.
Hydrological model of peat‐mound form with vertically varying hydraulic conductivity
Authors: Armstrong Adrian C. 
Published: February 2007

AbstractThe form of raised peat mires can be considered to reflect the form of the saturated water mound. Ingram (1982) calculates this form from hydraulic considerations, but assumes a uniform hydraulic conductivity throughout the profile. Here, the form of the mire is calculated for non‐uniform, depth‐dependent hydraulic conductivity of the peat deposit. Although requiring more computational effort, the alternative model may offer a more appropriate description of the structure of the peat mire.
Lichens: Lichenometric dating of diachronous surfaces
Authors: McCarroll Danny 
Published: February 2007

AbstractThis paper describes software to accompany McCarroll, D. 1993. ‘Modelling late‐Holocene snow‐avalanche activity: incorporating a new approach to lichenometry’, Earth Surface Processes and Landforms 18, 527–539; and McCarroll, D., Matthews, J. A. and Shakesby, R. A. 1995. ‘Late‐Holocene snow‐avalanche activity in southern Norway: interpreting lichen‐size‐frequency distributions using an alternative to simulation modelling’, Earth Surface Processes and Landforms 20, 465–471.
Orthogonality of modal bases in hp finite element models
Authors: Prabhakar V. , Reddy J. N. 
Published: February 2007

AbstractIn this paper, we exploit orthogonality of modal bases (SIAM J. Sci. Comput. 1999; 20:1671–1695) used in hp finite element models. We calculate entries of coefficient matrix analytically without using any numerical integration, which can be computationally very expensive. We use properties of Jacobi polynomials and recast the entries of the coefficient matrix so that they can be evaluated analytically. We implement this in the context of the least‐squares finite element model although this procedure can be used in other finite element formulations. In this paper, we only develop analytical expressions for rectangular elements. Spectral convergence of the L2 least‐squares functional is verified using exact solution of Kovasznay flow. Numerical results for transient flow over a backward‐facing step are also presented. We also solve steady flow past a circular cylinder and show the reduction in computational cost using expressions developed herein. Copyright © 2007 John Wiley & Sons, Ltd.
A stabilized finite element method for shape optimization in low Reynolds number flows
Authors: Srinath D. N. , Mittal S. 
Published: February 2007

AbstractA gradient‐based optimization procedure based on a continuous adjoint approach is formulated and implemented for steady low Reynolds number flows. A stabilized finite element formulation is proposed to solve the adjoint equations. The accuracy of the gradients from the adjoint approach is verified against the ones computed from a simple finite difference procedure. The validation of the formulation and its implementation is carried out via flow past an elliptical bump whose eccentricity is used as a design parameter. Shape design studies for the elliptical bump are then carried on with a more complex 4th order Bézier parametrization of the bump. Results for, both, optimal design and inverse problems are presented. Using different initial guesses, multiple optimal shapes are obtained. A multi‐objective function with additional constraints on the volume and the drag coefficient of the bump is utilized. It is seen that as more constraints are added to the objective function the design space is constrained and the multiple optimal shapes become progressively similar to each other. The study demonstrates the usefulness of this tool in obtaining multiple engineering solutions to a given design problem and also providing a framework to impose multiple constraints simultaneously. Copyright © 2007 John Wiley & Sons, Ltd.
A partially linear tree‐based regression model for assessing complex joint gene–gene and gene–environment effects
Authors: Chen Jinbo , Yu Kai , Hsing Ann , Therneau Terry M. 
Published: February 2007

AbstractThe success of genetic dissection of complex diseases may greatly benefit from judicious exploration of joint gene effects, which, in turn, critically depends on the power of statistical tools. Standard regression models are convenient for assessing main effects and low‐order gene–gene interactions but not for exploring complex higher‐order interactions. Tree‐based methodology is an attractive alternative for disentangling possible interactions, but it has difficulty in modeling additive main effects. This work proposes a new class of semiparametric regression models, termed partially linear tree‐based regression (PLTR) models, which exhibit the advantages of both generalized linear regression and tree models. A PLTR model quantifies joint effects of genes and other risk factors by a combination of linear main effects and a non‐parametric tree ‐structure. We propose an iterative algorithm to fit the PLTR model, and a unified resampling approach for identifying and testing the significance of the optimal “pruned” tree nested within the tree resultant from the fitting algorithm. Simulation studies showed that the resampling procedure maintained the correct type I error rate. We applied the PLTR model to assess the association between biliary stone risk and 53 single nucleotide polymorphisms (SNPs) in the inflammation pathway in a population‐based case‐control study. The analysis yielded an interesting parsimonious summary of the joint effect of all SNPs. The proposed model is also useful for exploring gene–environment interactions and has broad implications for applying the tree methodology to genetic epidemiology research. Genet. Epidemiol. © 2007 Wiley‐Liss, Inc.
A spatial probit model for fine‐scale mapping of disease genes
Authors: De Iorio Maria , Verzilli Claudio J. 
Published: February 2007

AbstractWe present a novel statistical method for linkage disequilibrium (LD) mapping of disease susceptibility loci in case‐control studies. Such studies exploit the statistical correlation or LD that exist between variants physically close along the genome to identify those that correlate with disease status and might thus be close to a causative mutation, generally assumed unobserved. LD structure, however, varies markedly over short distances because of variation in local recombination rates, mutation and genetic drift among other factors. We propose a Bayesian multivariate probit model that flexibly accounts for the local spatial correlation between markers. In a case‐control setting, we use a retrospective model that properly reflects the sampling scheme and identify regions where single‐ or multi‐locus marker frequencies differ across cases and controls. We formally quantify these differences using information‐theoretic distance measures while the fully Bayesian approach naturally accommodates unphased or missing genotype data. We demonstrate our approach on simulated data and on real data from the CYP2D6 region that has a confirmed role in drug metabolism. Genet. Epidemiol. 2007. © 2007 Wiley‐Liss, Inc.
One degree of freedom for dominance in indirect association studies
Authors: Chapman Juliet , Clayton David 
Published: February 2007

AbstractUsual tests of association using tag single nucleotide polymorphisms (SNPs) assume that the alleles of the causal locus act additively and that these alleles are then predicted indirectly via a set of tag SNPs. In the presence of strong dominance effects this model is not correct and an extra term needs to be included, which uses the tag SNPs to predict the heterozygosity of the causal locus. Assuming this scenario of a strong dominance effect, we present an appropriate test statistic and investigate how much power, if any, we gain by adding this single degree of freedom for dominance.Genet. Epidemiol. 2007. © 2007 Wiley‐Liss, Inc.
Aspects of the evolution of the drainage pattern of north‐east wales the evidence of upper erosion surfaces
Authors: Wilkinson H. R. , Gregory S. 
Published: February 2007

AbstractThe upper erosion surfaces of North‐east Wales are plotted and the evolution of the drainage system is traced. A warped and wasted envelope surface of Eocene age is recognized. There is evidence of a late Miocene peneplain at an elevation ranging from 2,200 to 1,800 feet. Into this have been cut numerous valley levels of Pliocene age from which the initial drainage of the Proto‐Dee can be reconstructed and its subsequent break‐up traced.
Notes on the faults of the bala district
Authors: Bassett D. A. 
Published: February 2007

AbstractIn a recent re‐survey of the Bala District the following sets of minor faults have been recognised: two sets of pre‐cleavage, strike‐slip faults which are apparently related to a number of small shear zones and which have no known equivalents in adjoining areas; a complementary system of post‐cleavage, strike‐slip faults which are correlated with similar faults in other parts of North Wales; a set of post‐cleavage, dip‐slip faults probably younger than the complementary ones; and a set of oblique‐slip faults parallel to the main Bala Fault and presumably of the same age.
Hillhouse coastal deposits in South Lancashire
Authors: Gresswell R. Kay 
Published: February 2007

AbstractRecent borings have provided considerable additional information in connection with the post‐glacial evolution of south‐west Lancashire. The position of the Hillhouse coastline in the area between Hundred End and Holmeswood (previously surmised) has now been determined, and the estuary of the extended river Yarrow confirmed. The boundary between Shirdley Hill Sand and Down‐holland Silt beach deposits is more exactly known than heretofore, and the positions of overlap of these deposits are studied. The overlying peat is divided into different types in accordance with the physical conditions prevailing during the period of its formation, and the distribution of forestal remains is mapped. Intervening river Alt alluvium is found in the district east of Formby.
The “Geological Population” as a framework for analysing numerical data in geology
Authors: Krumbein W. C. 
Published: February 2007

AbstractThe amount of numerical data in geology has increased markedly during the past several decades. The numbers arise from field and laboratory measurements on rocks and fossils, as well as from controlled laboratory experimentation on geological processes. Much of the numerical data represents sample observations on larger classes of objects or events about which inferences and predictions are made from the observational data. These larger classes constitute geological populations. In this framework of population and sample, modern probability and statistical methods provide the essential means for expressing generalizations and predictions at specified levels of reliability.
Palæomagnetism
Authors: Clegg J. A. 
Published: February 2007

AbstractThe results of numerous palæomagnetic measurements made on rocks during the past decade have been interpreted according to various schemes based upon either or both of the assumptions of polar wandering and the relative movements of continents. Recently, however, certain criticisms have been directed against this approach and a new analysis has been made to reassess the available information, relying on as few preconceptions as possible about the eventual explanation of the data. It can be demonstrated that for older rocks there is a well defined deviation of the measured remanent magnetic vectors from the present geomagnetic field, which increases progressively with geological age. For the four continents in which the results are best attested this deviation shows a systematic trend, and some genuine phenomenon is established. A combination of polar wandering together with continental drift provides an explanation of the results to date. On the other hand, on the present evidence, the possibility cannot be ignored that the observed effects may be due to strong multipolar components in the ancient magnetic field of the earth: alternatively it is conceivable although improbable that they can be explained by some widespread geological activity such as tectonic stresses of continental extent. The most plausible conclusion appears to be that continental drift has taken place, and on this tentative assumption the magnitudes of the land movements can be estimated from the data now available.
Sequences in Hominoid evolution
Authors: Weiner J. S. 
Published: February 2007

AbstractIn the generally accepted mammalian classification, the higher Primates including Man are classified as follows:—Suborder ANTHROPOIDEASuperfamily CEBOIDEASuperfamily CERCOPITHECOIDEASuperfamily HOMINOIDEAFamily Pongidae (Genera Hylobates, Pongo, Pan, GorillaFamily Hominidae (Genera Extinct genera.
Australopithecus,Pithecanthropus, Homo.This is of course primarily a taxonomic scheme. How far is it also an evolutionary scheme and what are the probable phyletic relationships, particularly within the Hominoidea? There are two questions of particular importance: (a) What is the relationship of pongid to hominid, is it one of common ancestry? (b) If so, what is the nature of this common ancestral stage?We can answer these questions quite conveniently by looking in turn first at the hominid evolutionary sequence and then at the pongid sequence.
The case against a lower palaeozoic geosyncline in Wales
Authors: Boswell P. G. H. 
Published: February 2007

AbstractThe author contends that we are in danger of spoiling further a term which has been, in its time, of great service in geology, if we describe as geosynclinal the Lower Palaeozoic rocks in Wales.Their facies and distribution yield no evidence that they were deposited in an elongated trough. At the present day they occupy an almost equidimensional area which is made up of a series of basins of deposition modified by tectonics of the platform type. The “mountains” of Wales (ca. 3000 ft.) are irregularly‐distributed monadnocks on a dissected plateau, and owe their elevation to resistant lavas, fragmental volcanic rocks and basic intrusions. There is no mountain chain of either Caledonian or later age. The rocks are predominantly conglomerates, sandstones, siltstones, mudstones and shales (slates): limestones are thin, scarce and scattered. Ultrabasic intrusives are very rare; and granites insignificant and of doubtful age. No metamorphic rocks (apart from slates) are known younger than Pre‐Cambrian. Shelf and basin facies have been identified at a few horizons and in certain areas, but much work remains to be done in this field. The statement that they are symmetrically distributed, and hence the styling of the geosyncline as the prototype of a new variety, the symmetrical geosyncline, are not warranted.No deep borings from which information about thicknesses could be obtained have been sunk. Estimates from field evidence show that no great thickness of sediments occurs at any particular locality. Breaks in the succession are numerous and widespread. The method of summating “restored” maximum thicknesses of formations and citing the aggregate is of doubtful value in view of the well‐known tendency for the compensatory thickening and thinning of formations as they are traced laterally. Local occurrences of high dips, steep folding and up‐thrusting are not regarded as evidence of orogenesis. It is therefore concluded that the Welsh region consists of a series of gently‐folded basins, in which the facies, thicknesses, trends and structures vary, situated on the south of the Scoto‐Scandinavian geosyncline.