bluuebunny/crossref_metadata_2025 huggingface dataset:
The P-113 Fragment of Histatin 5 Requires a Specific Peptide Sequence for Intracellular Translocation inCandida albicans, Which Is Independent of Cell Wall Binding
Authors: Jang Woong Sik , Li Xuewei Serene , Sun Jianing N. , Edgerton Mira
Published: November 2007

The activity of histatin 5 (Hst 5) againstCandida albicansis initiated through cell wall binding, followed by translocation and intracellular targeting. TheC. albicanscell wall protein Ssa2 is involved in the transport of Hst 5 into cells as part of cell killing. P-113 (a 12-amino-acid candidacidal active fragment of Hst 5) and P-113Q2.10 (which is inactivated by a glutamine substitution of the Lys residues at positions 2 and 10) were compared for their levels of cell wall binding and intracellular translocation inCandidawild-type (wt) andssa2Δ strains. Both P-113 and P-113Q2.10 bound to the walls ofC. albicanswt andssa2Δ cells, although the quantity of P-113Q2.10 in cell wall extracts was higher than that of P-113 in both strains. Increasing the extracellular NaCl concentration to 100 mM completely inhibited the cell wall association of both peptides, suggesting that these interactions are primarily ionic. The accumulation of P-113 in the cytosol of wt cells reached maximal levels within 15 min (0.26 μg/107cells), whilessa2Δ mutant cells had maximal cytosolic levels of less than 0.2 μg/107cells even after 30 min of incubation. Furthermore, P-113 but not P-113Q2.10 showed specific binding with a peptide array ofC. albicansSsa2p. P-113Q2.10 was not transported into the cytosol of eitherC. albicanswt orssa2Δ cells, despite the high levels of cell wall binding, showing that the two cationic lysine residues at positions 2 and 10 in the P-113 peptide are important for transport into the cytosol and that binding and transport are independent functional events.
Habitat use patterns in relation to escape terrain: are alpine ungulate females trading off better foraging sites for safety?
Authors: Hamel S. , Côté S.D.
Published: November 2007

Predation risk often forces prey to trade off good foraging sites for safety, and compromises are expected to be greater in females with vulnerable offspring than in barren females. To determine whether adult females of large herbivores traded off forage for safety, we assessed habitat use and estimated vegetation abundance and quality in relation to distance to escape terrain in marked mountain goats ( Oreamnos americanus de Blainville, 1816). We found that all females spent more time foraging near escape terrain than away from them. Females with young foraged on average 20 m closer to escape terrain than barren females in June, a time when offspring were particularly vulnerable to predation. Plant biomass did not vary with distance to escape terrain in June, but was lower closer than away from escape terrain during all other months. The abundance of forbs and shrubs increased with distance to escape terrain, but their quality did not vary. For grasses and sedges, plant digestible content decreased closer to escape terrain, but interestingly proteins increased. Our results suggest that females traded off forage abundance, and to a lesser extent forage quality, for safety. Compared with barren females, females with offspring may face a trade-off in plant digestible content by foraging in safer areas than barren females.
Sex and sociality in a disconnected world: a review of the impacts of habitat fragmentation on animal social interactionsThis review is one of a series dealing with some aspects of the impact of habitat fragmentation on animals and plants. This series is one of several virtual symposia focussing on ecological topics that will be published in the Journal from time to time.
Authors: Banks Sam C. , Piggott Maxine P. , Stow Adam J. , Taylor Andrea C.
Published: November 2007

Despite the extensive literature describing the impacts of habitat fragmentation on the distribution and abundance of species, fragmentation effects on life-history strategies have been relatively understudied. Social interactions are important life-history attributes that have fitness consequences for individuals and have been observed to differ among populations in relation to geographic and demographic variability. Therefore, habitat fragmentation is expected to affect social interactions, and these social impacts or responses may contribute to population viability and broad-scale patterns of distribution and abundance in fragmented landscapes. Here we review the emerging literature on this issue. We focus on the impacts of habitat fragmentation that are expected to, or have been observed to, affect social strategies. These include altered resource distribution (e.g., habitat quality, spatial configuration of patches), interspecific interactions (e.g., predator–prey and host–parasite dynamics, human disturbance), and sex (mate availability and inbreeding risk). The studies we cite identified altered social interactions in response to these influences, including changes to home-range overlap, territoriality, group size, and mating systems. The observed changes to social interactions include passive responses, whereby social interactions are affected by constraints introduced by habitat fragmentation, and adaptive social responses to a modified environment. We suggest that future research could focus on individual fitness benefits and on consequences for population viability of altered social interactions in fragmented environments.
The genetic implications of habitat fragmentation for animalsThis review is one of a series dealing with some aspects of the impact of habitat fragmentation on animals and plants. This series is one of several virtual symposia focussing on ecological topics that will be published in the Journal from time to time.
Authors: Keyghobadi Nusha
Published: November 2007

The past decade has seen a rapid increase in the number of studies dealing with the genetic consequences of habitat fragmentation, in large part because of the increasing accessibility of techniques for assessing molecular genetic variation in wild populations. This body of work is extremely diverse and encompasses a variety of approaches that define and measure both habitat fragmentation and its potential genetic impacts. Here, I summarize the main questions that are being addressed, and approaches being taken, in empirical studies of the genetic impacts of habitat fragmentation in animals. Considerable effort has been spent in documenting how levels of genetic diversity, and the spatial distribution of that diversity, are altered by habitat fragmentation. However, proportionately less effort has been invested in directly examining specific genetic and evolutionary processes that may affect the persistence of populations inhabiting fragmented landscapes: inbreeding depression, the loss of adaptive potential, and the accumulation of deleterious mutations. One area in which considerable progress has been made over the past decade is in the development and application of novel methods for inferring demographic and landscape ecological characteristics of animals, particularly dispersal patterns, using genetic tools. In this area, a significant integration of genetic and ecological approaches in the study of fragmented populations is occurring.
Lp APPROXIMATION CAPABILITIES OF SUM-OF-PRODUCT AND SIGMA-PI-SIGMA NEURAL NETWORKS
Authors: LONG JINLING , WU WEI , NAN DONG
Published: November 2007

This paper studies the Lp approximation capabilities of sum-of-product (SOPNN) and sigma-pi-sigma (SPSNN) neural networks. It is proved that the set of functions that are generated by the SOPNN with its activation function in [Formula: see text] is dense in [Formula: see text] for any compact set [Formula: see text], if and only if the activation function is not a polynomial almost everywhere. It is also shown that if the activation function of the SPSNN is in [Formula: see text], then the functions generated by the SPSNN are dense in [Formula: see text] if and only if the activation function is not a constant (a.e.).
BORN RECIPROCITY IN TWO DIMENSIONS: QUAPLECTIC GROUP SYMMETRY, BRANCHING RULES AND STATE LABELLING
Authors: JARVIS P. D.
Published: November 2007

We consider the continuous symmetry group underlying Born's reciprocity principle, namely the so-called quaplectic group, the semidirect product of time-space-energy-momentum coordinate transformations with the Weyl-Heisenberg group. In two dimensional Minkowski space this group is Q(1, 1) ≅ U(1, 1) ⋉ H(2), or in Euclidean space Q(2) ≅ U(2) ⋉ H(2). For the 'scalar' system in the sense of induced representations, unitary irreducible representations are carried on a Fock space equivalent to that used by Schwinger as a model of the SU(2) angular momentum algebra, or by Holman and Biedenharn as a model of SU(1,1). Using this construction we consider the branching rules and state labelling problem for the reduction of Q(2) and Q(1, 1) to the 'physical' Euclidean and Poincaré subalgebras, respectively. The results serve to illustrate the difficulties of any consideration of Born reciprocity as an extended symmetry principle of nature.
QUANTUM HAMILTON MECHANICS AND THE THEORY OF QUANTIZATION CONDITIONS
Authors: BRACKEN PAUL
Published: November 2007

A formulation of quantum mechanics in terms of complex canonical variables is presented. It is seen that these variables are governed by Hamilton's equations. It is shown that the action variables need to be quantized. By formulating a quantum Hamilton equation for the momentum variable, the energies for two different systems are determined. Quantum canonical transformation theory is introduced and the geometrical significance of a set of generalized quantization conditions which are obtained is discussed.
NORMAL-MAP BETWEEN NORMAL-COMPATIBLE MANIFOLDS
Authors: CHAZAL FREDERIC , LIEUTIER ANDRE , ROSSIGNAC JAREK
Published: November 2007

Consider two (n−1)-dimensional manifolds, S and S′ in ℝn. We say that they are normal-compatible when the closest projection of each one onto the other is a homeomorphism. We give a tight condition under which S and S′ are normal-compatible. It involves the minimum feature size of S and of S′ and the Hausdorff distance between them. Furthermore, when S and S′ are normal-compatible, their Frechet distance is equal to their Hausdorff distance. Our results hold for arbitrary dimension n.
HOMOTOPY-PRESERVING MEDIAL AXIS SIMPLIFICATION
Authors: SUD AVNEESH , FOSKEY MARK , MANOCHA DINESH
Published: November 2007

We present a novel algorithm to compute a simplified medial axis of a polyhedron. Our simplification algorithm tends to remove unstable features of Blum's medial axis. Moreover, our algorithm preserves the topological structure of the original medial axis and ensures that the simplified medial axis has the same homotopy type as Blum's medial axis. We use the separation angle formed by connecting a point on the medial axis to closest points on the boundary as a measure of the stability of the medial axis at the point. The medial axis is decomposed into its parts that are the sheets, seams and junctions. We present a stability measure of each part of the medial axis based on separation angles and examine the relation between the stability measures of adjacent parts. Our simplification algorithm uses iterative pruning of the parts based on efficient local tests. We have applied the algorithm to compute a simplified medial axis of complex models with tens of thousands of triangles and complex topologies.
Natural geochemical concentrations and fluxes of Cu, Th and U in Finland
Authors: Tarvainen Timo , Hellmuth Karl-Heinz , Backman Birgitta
Published: November 2007

Concentrations of U, Th and Cu were studied as a part of the coordinated IAEA (International Atomic Energy Agency) research project on ‘The use of selected safety indicators (concentrations; fluxes) in the assessment of radioactive waste disposal’. Uranium and Th served as analogues of radionuclides in the waste matrix (spent fuel) and Cu is a construction material in the Finnish disposal approach in granitic rock. Release and migration of these components through the geosphere to the biosphere is thought to be caused and influenced by corrosion, oxidation and dissolution and subsequent transport and retardation processes in groundwater in hydraulically conducting rock fractures.

The weathering rates for Cu, U and Th were calculated on the basis of the weathering rate of base cations and the concentrations of these elements in the parent soils. The mean weathering rate for Cu in till soils is 0.21 mg m
−2
a
−1
. The mean values of estimated weathering rates for Th and U are 0.17 mg m
−2
a
−1
and 0.054 mg m
−2
a
−1
, respectively.

Analytical data and flux measurements from groundwater monitoring of selected springs are used to calculate the quantity of dissolved elements discharging from the aquifer. Typical fluxes for five small springs were 0.023–0.46 kg Cu km
−2
a
−1
and 0.003–0.43 kg U km
−2
a
−1
. The estimated fluxes of Cu and U in headwater streams were calculated on the basis of concentration data and the rate of stream flow. The estimated fluxes in 30 streams are 0.44–1418 g/month for Cu and 0.08–285 g/month for U.

From the point of view of the use of natural elemental concentrations and fluxes as natural safety indicators in the evaluation of nuclear waste repository, the basis of this complementary or alternative concept has been corroborated by the results of this work. Elemental concentration data can be better understood in relation to the underlying geology and the prevailing geochemistry and by correlation to observed elemental fluxes. The comparison of the spatial distribution of elements in different matrices gives a qualitative estimation of the dominating fluxes.

Widespread correlation between different compartments indicates mobile element fluxes from the geosphere to the biosphere. Also fixation in sinks, in particular, for U was observed. The geochemical cycles are dominated by near-surface weathering processes. Fluxes are also controlled by small-scale, local groundwater flow patterns; contributions from greater depths were found to be negligible.
Environmental geochemistry at Red Mountain, an unmined volcanogenic massive sulphide deposit in the Bonnifield district,Alaska Range, east-central Alaska
Authors: Eppinger Robert G. , Briggs Paul H. , Dusel-Bacon Cynthia , Giles Stuart A. , Gough Larry P. , Hammarstrom Jane M. , Hubbard Bernard E.
Published: November 2007

The unmined, pyrite-rich Red Mountain (Dry Creek) deposit displays a remarkable environmental footprint of natural acid generation, high metal and exceedingly high rare earth element (REE) concentrations in surface waters. The volcanogenic massive sulphide deposit exhibits well-constrained examples of acid-generating, metal-leaching, metal-precipitation and self-mitigation (via co-precipitation, dilution and neutralization) processes that occur in an undisturbed natural setting, a rare occurrence in North America. Oxidative dissolution of pyrite and associated secondary reactions under near-surface oxidizing conditions are the primary causes for the acid generation and metal leaching. The deposit is hosted in Devonian to Mississippian felsic metavolcanic rocks of the Mystic Creek Member of the Totatlanika Schist.

Water samples with the lowest pH (many below 3.5), highest specific conductance (commonly >2500 μS/cm) and highest major- and trace-element concentrations are from springs and streams within the quartz–sericite–pyrite alteration zone. Aluminum, Cd, Co, Cu, Fe, Mn, Ni, Pb, Y, Zn and, particularly, the REEs are found in high concentrations, ranging across four orders of magnitude. Waters collected upstream from the alteration zone have near-neutral pH, lower specific conductance (370 to 830 μS/cm), lower metal concentrations and measurable alkalinities. Water samples collected downstream of the alteration zone have pH and metal concentrations intermediate between these two extremes. Stream sediments are anomalous in Zn, Pb, S, Fe, Cu, As, Co, Sb and Cd relative to local and regional background abundances. Red Mountain Creek and its tributaries do not, and probably never have, supported significant aquatic life.
Identification and location of transmissive fractures from analysis of tracer test data
Authors: Kim Yong-Cheol , Lee Kang-Kun
Published: November 2007

This study examines well-to-well tracer tests in crystalline rock aquifers in which the injected tracer is transported through a limited number of fracture channels even though many such channels may exist. The fractures that act as the significant paths of solute movement are termed transmissive fractures, and the location and properties of these fractures must be known for solute transport phenomena to be accurately analyzed. This study proposes semi-analytical solutions for tracer breakthrough curves at any depth in an observation well, at any point in time. These solutions were obtained from successive application of 2-D advective and dispersive transport models in the transmissive fractures, and 1-D diffusive transport model in the observation well. The solutions can be applied to locate the transmissive fracture along an observation well from tracer tests. Once the location of the transmissive fracture is known, the advective and dispersive characteristics of solute transport through the transmissive fracture can be estimated. A graphical method to determine the location of the transmissive fracture and to estimate the diffusive transport along an observation well is proposed. This method has been successfully applied to laboratory tests.
Understanding a complex adit and shaft groundwater source in a Chalk aquifer
Authors: Zhang Beiyan , Lerner David N.
Published: November 2007

The Cottingham groundwater source is complex, comprising two pumping shafts, 17 other shafts and 1000 m of operational adit. Understanding the interaction between aquifer, adit and shafts is very important to assess the yield and vulnerabilityof the source. Numerical models are good tools to assemble and analyse field data and formulate ideas about system dynamics. An integrated groundwater,pipe and open-channel flow computer code has been developed by a combination of a Preissmann slot and MODBRNCH, and used to simulate the aquifer-aditsystem. Introducing a fictitious narrow slot (Preissmann slot) above the adit makes the equations for open-channel flow also valid for pipe flow. A model ofCottingham was calibrated against multiple targetsincluding initial and transient conditions, aquifer and adit heads, the head profiles for the initial condition, and the temporal changes of heads during a pumping test. Three alternative conceptual models were tested, each with different hydraulic assumptions about interactionbetween aquifer, adit and shafts. Only one model was well calibrated to all targets, and had a variable ratio of inflows to shafts and adit. The study developed a new understanding of the hydraulics and hydrogeology of the complex Cottingham adit and shaft system.
The effects of acid mine drainage from an old mine in the Witbank Coalfield, South Africa
Authors: Bell F.G. , Hälbich T.F.J. , Bullock S.E.T.
Published: November 2007

Acid mine drainage seeping from an abandoned mine in the Witbank Coalfield has flowed into a nearby stream, the Blesbokspruit, which is a tributary of the Olifants River. The amount of precipitation over the mine area which sinks into the mine has been greatly increased by associated subsidence features. There is a time lag between the maximum precipitation and the maximum flow of acid mine drainage from the mine of several months. The water issuing from the mine has a low pH, high electrical conductivity and high total dissolved solids. It has severely impaired the quality of the waters of the Blesbokspruit. The heavy metals concentrations of the stream water are well above the levels set by the South African standards. In addition, there is a high concentration of heavy metals in the stream sediments and in algal mats which occur at the seepage points. Salts have been precipitated from the acidified waters, one of the chief of which is jarosite. Formation of ferrihydrite is associated with the algal mats.

Four decantation ponds constructed in the headwaters of this stream have had no effect on the pollution. Indeed, the concentration of aluminium in the waters exiting from the ponds is higher.

The Blesbokspruit flows through a wetland and on leaving the concentration of some heavy metals has been reduced. This presumably is attributable to the sorption capacity of the high organic content of the sediments in the wetland. Nonetheless, the quality of the water is not improved sufficiently for it to be acceptable, even with the dilution effect of the entry of water from an uncontaminated stream downstream of the wetland.
Implications of flow patterns in the sandstone aquifer beneath the mature conurbation of Nottingham (UK) for source protection
Authors: Trowsdale S.A. , Lerner D.N.
Published: November 2007

The protection of groundwater sources in urban areas is difficult due to uncertainties in hydrogeology, future changes in pumping, and complexities of land use. This paper presents an improved understanding of the hydrogeology of the Permo–Triassic Sherwood Sandstone aquifer underNottingham, and considers protection policies for this example of a highly developed groundwater system. Groundwater flow models were constructed for the pre-industrial period (before 1850) and for the 1980 s, and confirmed the existing conceptual model of the hydrogeology. In the early period, spring flows were much more significant than they are now, while abstractions through wells account for virtually all the discharge in the recent period. In recent decades, abstraction has fallen, but there has been a significant reduction in recharge from mains leakage so that there has been no overall rise in groundwater levels. Particle tracking revealed that during recent times the regional aquifer has behaved as a series of local flow cells rather than a regional whole due to the numerous abstractions. Wells in the unconfined aquifer capture most of the urban (and potentiallypolluted) recharge with travel-times up to 200 years. Confined wells with travel-times over 10
4
years, will abstract pre-industrial waters for years to come, and are likely to be protected by natural attenuation of pollutants.

Deterministic source protection zones will not be fully protective of public and industrial water supplies, due to the likely changes in pumping regimes in future and the resourcing implications of attempting to control polluting activities over the whole city. A risk-based approach to managing urban groundwater may be more practical and useful. It could predict the risks to existing water supplies, and help in the selection of low risk locations for new wells.
The effects of storage conditions on the sulphur speciation in geological material
Authors: Czerewko M.A. , Cripps J.C. , Reid J.M. , Duffell C.G.
Published: November 2007

The corrosion of galvanized steel buriedstructures and the deterioration of buriedconcrete structures are problems attributed to the presence of sulphate and sulphide species in the structural backfill and natural ground surrounding the buried structures.

Avoidance of these problems depends on reliable chemical testing of samples of the materials in the first instance. However, the results of tests may be incorrect because of oxidation of sulphur minerals during sample storage. Results are presented in this paper of aninvestigation carried out into the effects that different storage conditions have on the sulphur species, particularly oxidation of pyrite and growth of gypsum. The findings show that pyrite oxidation will occur withinstorage periods of weeks to months affecting subsequent chemical test results for sulphur species. In this paper guidance on suitable storage and testing protocols is provided.
Quantitative Landslide Hazard and Risk Assessment:a case study
Authors: Ko Ko Chit , Flentje Phil , Chowdhury Robin
Published: November 2007

This paper is concerned with landslide hazard and risk assessment along a railway line south of Sydney in the State of New South Wales, Australia. Attention is focused on a quantitative assessment at a specific site where landslide movements have been triggered by significant rainfall. Although small in magnitude such movements are sufficient to cause train derailment and hence human casualty. Utilizing all available data, the relationship of slope instability to rainfall is first established. Slope stability analyses are carried out to validate the proposed geological-geotechnical model. The concept of landslide triggering critical rainfall magnitude (specific to a given site) is proposed in this paper. Detailed rainfall analysis reported elsewhere (
Ko Ko 2001
) leads to the conclusion that the most significant period of antecedent cumulative rainfall for this site is 15 days. The historical rainfall data then leads to an estimation of landslide frequency or hazard. The risk to human casualty is then based on an analysis of train operations and their frequency. Different results are obtained for the tourist train service and the freight train service. Some attention is given to tolerable risk criteria proposed elsewhere in the literature.
The design, construction and testing of a horizontal wellpoint in a dune sands aquifer as a water source
Authors: Brassington F.C. , Preene M.
Published: November 2007

Ahorizontal wellpoint has been constructed to supply irrigation water to a golf course froma coastal dune sands aquifer. The sourceprovides the required quantities with relatively limited drawdown compared with what would beexpected from a conventional vertical wellpoint system. Pumping test data have been analysed using a curve fitting method based on parabolic isochrone curves. The resulting values for the aquifer characteristics fall within their anticipated range.
Large diameter plate tests on weathered

in-situ

Chalk
Authors: Matthews M.C. , Clayton C.R.I.
Published: November 2007

The prediction of the settlements of spreadfoundations on
in-situ
chalk is best carried out using empirical methods, based on the simple behavioural model developed by
Burland & Lord (1970)
using results from plate tests. However, the data available to support this approach remain somewhat limited, stratigraphically, geographically and in terms of size and level of loading. This paper reports the results of nine large (1.8 m) diameter plate tests carried out on three weathered chalks with widely different intact densities and strengths. The results are interpreted in terms of the Burland and Lord model, and despite the differences in the chalks at these sites, are found to be broadly in agreement with the parameters deduced on the basisof the pioneering work carried out at Mundford by

Ward
et al
. (1968)

. In addition the paper provides someadditional data on creep settlements, confirming that the long-term settlements on chalk can be considerably larger than those predicted on the basis of short-term loading tests.
Overland flow generation processes, erosion yields and solute loss following different intensity fires
Authors: Coelho Celeste de Oliveira Alves , Ferreira António José Dinis , Boulet Anne-Karine , Keizer Jan Jacob
Published: November 2007

Fire induces important changes in vegetation and soil structure, which can have major impacts on overland flow generation processes, runoff amounts and erosion yields. This paper presents the results of an investigation into the impact of different fire intensities on water, sediment and solute yields. Wildfire, prescribed fire and experimental fire impacts were investigated at two scales: (1) a temporary circular bounded plot of 0.24 m
2
(rainfall simulation plot); (2) a permanent bounded runoff plot of 16 m
2
(natural rainfall conditions). In addition, the spatial patterns of the soil water repellency, vegetation, litter cover and stone cover for each land use and fire intensity were assessed using a transect system.The results of this study show a significant difference in the spatial distribution patterns of soil water repellency. Wildfire sites were characterized by more intense and by more spatially contiguous repellency than the experimental and prescribed fire sites. These differences have important effects on overland flow generation processes and runoff amounts. At the prescribed and experimental fire sites, the discontinuous distribution of repellency provides greater potential for water to infiltrate via non-repellent soils, whereas there are far fewer infiltration pathways at the wildfire sites because of their spatially contiguous repellency. This spatial discontinuity (alternation between hydrophobic and hydrophilic soil patches) is therefore responsible for the lower overland flow amounts, smaller erosion rates and nutrient yields at broader scales, when compared with the wildfire burned areas where soil water repellence is more intense and spatially contiguously distributed.
Reservoir sedimentation associated with landsliding, Atrak watershed, Iran
Authors: Ghafoori M. , Lashkaripour G.R.
Published: November 2007

The Barezoo dam on the Gholjogh River, a branch of the Atrak River with a catchment area of 491.7 km
2
, is located about 18 km north of Shirvan city in NE Iran. Landslides are an important natural hazard in the Atrak watershed and cause serious problems for the maintenance of the Barezoo reservoir. Landslide occurrence is controlled by lithology, slope of the terrain, and natural and human actions that may either add to the operating gravitational stresses or reduce the resistance to sliding of the soils forming the slope. The interaction between local geology and climatic conditions in this area has resulted in landforms with varying degrees of susceptibility to landsliding. Dammed watersheds in NE Iran experience numerous landslide and sedimentation problems. A quantitative approach based on a numerical rating scheme called the landslide hazard evaluation factor rating scheme was used to evaluate and describe landslides and their resultingsedimentation in the Gholjogh watershed.
Pitfalls in the geological characterization of alluvial deposits: site investigation for reactive barrier installation at Aznalcóllar, Spain
Authors: Salvany J.M. , Carrera J. , Bolzicco J. , Mediavilla C.
Published: November 2007

The alluvial deposits of the Agrio River in SW Spain have been studied using terrace mapping, boreholes, trenching and vertical electrical sounding to select an adequate place for a Permeable Reactive Barrier. Geological and hydrogeological data available prior to the barrier construction suggested a simple geological model based on three terraces, the most modern being deeper than the oldest. The barrier was accordingly trenched through the youngest terrace. However, excavation of the barrier andsubsequent subsoil data demonstrated that the internal structure of the Agrio alluvial deposits does not follow such a simple model. A revised model, less favourable to the existing barrier design, revealed the oldest terrace to be deeper than the youngest, and to form a palaeochannel oblique to the surface terraces and river trends. The study methods used are standard, but proved to have insufficient resolution to detect key features of the alluvial geology. It is concluded that such characterization methods, though widely used, are not appropriate where alluvial terraces may display complex internal structures not reflected in the modern surface geomorphology. In hindsight, the study area should have been larger, so as to encompass at least the width of the alluvial plain and to extend for a hundred metres or so up and downstream from the proposed barrier location. Lithological logs of the boreholes should have been carefully described from both cuttings and downhole geophysical logs, which would have allowed more accurate delineation ofthe stratigraphy of the alluvial deposit. Subsequentgeophysical methods should have been calibrated to this stratigraphy to characterize the internal structure and basal contact of the alluvial deposit.
Geomorphological roulette for engineers and planners: some insights into an old game
Authors: Brunsden D.
Published: November 2007

Engineers have always appreciated that a civil engineering project should be based on a clear understanding of the geomorphology of the site of the proposed works. It is an old ‘game’!

However, although it is good practice to take full account of the morphology and processes of the landscape during an investigation there is a tendency to restrict the work to basic mapping and identification of features rather than a true understanding of the site in space and time. Particular criticisms are that not enough attention is paid to the effects of landform change, the identification of inherited material conditions, the frequency and magnitude of processes and the nature of risk. Ways of improving the service are identified.

It is suggested that future work should be based on a full understanding of the conceptual basis for modern geomorphology. In the past thirty years there has been a revolution in the theoretical basis of the subject as well as a remarkable improvement in the technical capability. A major statement is therefore made on the nature of geomorphology and this is then summarized as a possible conceptual basis for application to engineering and planning.

The theme of the paper will be illustrated by a description of the Lyme Regis Environmental Improvements Scheme in West Dorset which is in the design stage and has been based on a full understanding of the geomorphology and geology of the area and the employment of a Geo-Team at all stages of the project.
Materials surveys and investigation for the Kainji Dam project, Northern Nigeria
Authors: Hitchen Charles Stanfield
Published: November 2007

The Kainji Dam across the river Niger is the largest engineering project currently being constructed in Africa south of the Sahara and is due to be completed at the end of 1968.

Following a short reference to geological conditions, a description is given of the investigation and assessment of the indigenous materials available for the building of this dam and its associated works, comprising rock, gravel, sand and earth.

The paper demonstrates the way design was adapted to make the most effective and efficient use of these local materials and, hence, the prior need for their quantity and quality to be precisely established.
Consolidation characteristics of some kate Pleistocene periglacial metastable soils of East Kent
Authors: Fookes Peter George , Best Robert
Published: November 2007

Metastable partially saturated soils are those which on wetting under load undergo a sudden decrease of void ratio, i.e. a structural collapse. One of the most important soils of this group is loess, a silty quartzose sediment of uniform grading. Loess has attracted interest in the past because of its unusual mode of formation associated with wind transport, and its unusual behaviour as an engineering material. It has extremely widespread occurrence outside Britain but only occurs to any extent in small areas in east Kent and has only been reported occasionally from elsewhere in Britain.

The paper deals principally with the geotechnical and mineralogical characteristics of east Kent loess and some comparison is drawn with loess from various world-wide locations. The geotechnical behaviour supports the conclusions made from earlier geological observation which leave little room for doubt that the Kent loess is a true loess of periglacial origin. A coarser grained poorly sorted glacial solifluxion soil from Kent was also examined and found to be metastable. Because material of this type is fairly common this observation could have significant engineering implications.
Geological factors in the design and construction of the Ffestiniog Pumped Storage Scheme, Merioneth, Wales
Authors: Anderson John Graham Comrie
Published: November 2007

The Ffestiniog Pumped Storage Scheme, in Merioneth, the first in Britain, is situated on Upper Cambrian and Ordovician sediments and metasediments, on Ordovician volcanics and fine-grained intrusions and on a granite laccolite. The nature and structure of these rocks and the glacial history were major factors in the choice of site and in the design and construction of works which include two large dams, deep vertical shafts, pressure tunnels and penstocks, and a power station of 360 MW capacity.

The presence of a glaciated rock-lip of Ordovician igneous rocks located the upper dam site, but the effects of glacial drag necessitated deeper excavation than expected; faulting also had to be taken into account. Twin 640 ft vertical shafts pass down through the igneous rocks into Ordovician sediments. Four pressure tunnels and the power station site were excavated in flaggy Upper Cambrian rocks, subject to a varying degree of meta-morphism; in spite of well-marked bedding and cleavage and the presence of several faults (forecast from site investigation) these strata proved satisfactory both mechanically and hydraulically. Hornfelsed sediments provided sound foundations at shallow depth for the Lower Dam; deeper excavation was necessary in granite cut by minor faults and intrusions and affected by weathering.

Site exploration included nearly 4000 ft of core boring.

No new geological views are put forward but observations are recorded bearing on the relation of the granite to its aureole, on the nature of the Ordovician volcanics and intrusions, on the Cambrian/Ordovician boundary and on the fault and joint systems.
Topographical and petrographical variation of road aggregates and the wet skidding resistance of tyres
Authors: Williams Arthur Roger , Lees Geoffrey
Published: November 2007

Previous workers have noted variations in skid resistance value of aggregates of similar trade-group categorization and of similar petrographical grouping, due to detailed mineralogical and petrographical changes. Some further examples are noted and, with particular reference to limestone aggregates the cause of these variations is discussed, together with the question of blending aggregates of different polishing characteristics with the aim of achieving certain desired levels of skid resistance.

The topographical characteristics of aggregates of various type, natural and artificial and at various states of polish, have been studied by means of the Stereoscan electron microscope and related to petrographical detail, and to geological, crushing and polishing history.

The effect of different states of polish of a particular roadstone surface on the wet skidding resistance of rubber compounds is shown to be of the same order of magnitude as that encountered in testing a surface of a given state of polish with rubber compounds of poor and good wet-grip properties.
The Cornish greenstones: their physical properties and use in engineering
Authors: Hawkes Jan Robert , Cratchley Charles Roger
Published: November 2007

This note contains a brief account of the stratigraphy and mineralogy of the Cornish greenstones. Data obtained from ultrasonic, uniaxial compressive strength, Young's Modulus and wet and dry density tests are given for four greenstone types ranging from unmeta-morphosed to completely recrystallized contact-altered material. Differences in the results seem to reflect fairly closely the particular mineralogical and textural features of each sample. Commonly the greenstones are extremely tough rocks. Some of the implications of this fact are discussed with regard to site engineering problems, but more specifically with reference to past and present utilization and to the future potential greenstones could have as the raw material for engineering surface plates.
The behaviour of a soft recent sediment under embankment loadings
Authors: James Peter Michael
Published: November 2007

The behaviour under load of a thick deposit of normally consolidated recent sediments in north-west Malaya was studied by means of full-scale trial embankments. Two parallel embankments of 9 ft and 11 ft in height, with slopes averaging one vertical to two horizontal and lengths of about 200 ft were constructed. The soft foundation soils were investigated and instrumented, and provided the following information:

(1)The
in-situ
three-dimensional permeability of the stratum was some two to three orders of magnitude higher than the vertical permeability computed from laboratory tests.

(2) Consolidation settlements beneath the embankments were therefore extremely rapid and largely completed within two or three months of the end of construction, in contrast to periods of years predictable from oedometer tests.

(3) There appeared to be a reduction in the permeability of the soft foundation soils under-going settlement as well as an increase in strength of the soils, the latter occurring largely during the early consolidation stages.

(4) The major part of the settlement is believed to be provided by secondary consolidation of the soft soils, a process which is still continuing at the time of writing. Normal consolidation theory for settlement predictions is shown to be applicable only for loads below a certain threshold level. Some laboratory and field values of the coefficient of secondary consolidation,
C
α
, are quoted and the application of this parameter is briefly discussed.

(5) The normally consolidated sediments showed several characteristics typical of over-consolidation.

The results of the trial were invaluable in the design of further embankments in the area, and in avoiding installation of unwarranted measures such as sand drains.
A mineralogical investigation of a spoil heap at Yorkshire Main Colliery
Authors: Spears David Alan , Taylor Roy Kenneth , Till Roger
Published: November 2007

A spoil heap at Yorkshire Main Colliery has been investigated to determine whether or not the material buried within the heap is being weathered. Samples have been obtained from a borehole through the tip, and control samples from underground. The observed breakdown of the underground samples upon exposure has been related to the material in the spoil heap. It would appear that after the initial, relatively rapid physical breakdown, the material has changed little. Mineralogical and chemical analyses show that the level of chemical weathering does not increase with depth in the spoil heap. There appears to have been little movement of water through the spoil heap. Chemical analyses of the ground-water also shows no evidence for weathering. Small changes have been recorded with depth, but in all cases these are believed to be due to original variations in the material at the time of tipping.
The stability of a valley side in weathered shale
Authors: West John Michael , Moseley Michael Paul , Bennett Donovan Harry
Published: November 2007

The paper describes a detailed investigation carried out at Abersychan near Pontypool, South Wales, to determine the stability of a valley side prior to multi-storey development. A routine investigation revealed the presence of deeply weathered and disturbed shales beneath variable drift deposits, and despite the absence of visual evidence of slip at that time, initial calculations indicated a case of marginal stability. A rigorous investigation was then authorized to examine the stability of the site in detail, and this confirmed a case approximating to limiting equilibrium. The shear strength of the shale was found to be related to its mineralogical content and to be independent of its flocculated structure, which had not been destroyed by weathering. The use of standard classification tests to describe the true nature of such a soil was found to be unreliable. The information obtained from the two investigations was used to formulate a scheme of anchored reinforced concrete diaphragm walls capable of supporting multi-storey buildings and stabilizing the slope.
A sparker survey used to select a marine dam site in Hong Kong
Authors: Fanshawe Hew George , Watkins Mervyn David
Published: November 2007

An additional large reservoir will soon be needed in Hong Kong and the only suitable sites are for dams founded in the sea, similar to the recently completed Plover Cove dam. A sparker reflection survey has been carried out to compare three sites. To assist the interpretation, boreholes and drillholes were completed at possible centre-lines.

Results show that Pleistocene valleys were eroded deeply below present sea level and were subsequently infilled. Soft marine sediments cover compact alluvium above bedrock. The earth/rock fill dams would probably be founded on alluvium and the main object of the investigation was to find suitable foundation levels.

The sparker survey gave far more geological information than would have been obtained from exploratory holes drilled at the equivalent cost. The results were accurate enough to produce relative capital cost/capacity curves for the reservoir sites.
A preliminary report on new photogeological studies to detect unstable natural slopes
Authors: Watson Ian
Published: November 2007

1. Preliminary study

A P
reliminary
investigation of the stability problems of natural slopes in Southern England was carried out in 1968/69 using air photographs in conjunction with existing literature and a limited field study. General photoreconnaissance included the study of slopes consisting of the Inferior Oolite overlying the Lias south of Leicester, but with special attention to the scarp face of the Cotswold Hills between Broadway and Bath, the Lower Greensand overlying the Weald clay on the escarpment south and west of Sevenoaks in Kent and the Upper Greensand overlying the Gault on the Isle of Wight and in Dorset.

This study indicated that instability on slopes consisting of a clay overlain by a bed of significantly greater permeability was widespread enough to merit special attention. The following hypothesis was suggested to define the scope of further investigation.

2. Hypothesis and explanation

The hypothesis states:

wherever precipitation is sufficiently high, slopes consisting of a clay overlain by a bed of significantly greater competency and/or mass permeability, are likely to be actively degraded by mass movement (e.g. PL la-lf).

(In this context the following should be noted:

1. Competent and incompetent are used as relative terms. Competent materials are considered to be strong, to have a low deformability and to have brittle characteristics of failure. Incompetent materials are considered to be relatively weaker than competent materials, to have lower shear strengths, a higher deformability and to fail in a plastic way.

2. Mass permeability is taken to include both permeability and
The use of resistivity logging to estimate borehole yield from a matrix-conducting sandstone
Authors: Worthington Paul Francis
Published: November 2007

Borehole resistivity methods have been used to study the Bunter Sandstone aquifer of north-west Lancashire. The results of water-resistivity and ‘normal’ logging surveys are discussed. Using the determined distribution of ground-water resistivity an average formation factor is calculated for each well. This quantity is shown to be affected by conduction of the sandstone matrix, a phenomenon which is used to estimate hydraulic conductivity at borehole sites as follows. Within a limited section of the aquifer, values of hydraulic conductivity calculated from pump-test data are correlated with formation factors corrected for several assumed levels of matrix conduction. The most significant correlation furnishes an empirical relationship which permits the interpolation of hydraulic conductivity in terms of the resistivity data. Estimated values of hydraulic conductivity at the sites of unlogged wells are generally at least as accurate as those obtained directly from interpolated hydrological parameters. The possible extension of the method to predict potential well yields is briefly indicated.