bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pile foundation problems in Kuala Lumpur Limestone, Malaysia
Authors: Bergado D. T. , Selvanayagam A. N. 
Published: September 2007

Abstract
The geology and karstic nature of the Kuala Lumpur (Malaysia) limestone are described in relation to pile foundation problems of heavily loaded structures. The presence of cavities, pinnacles, cantilever slabs, floating slabs and pockets of soft silty clay and loose sand in the underlying limestone bedrock presents formidable challenges to foundation engineers. Other problems include insufficient seating and damage to pile tips due to irregular and sloping bedrock surfaces. There is also the added difficulty of detecting the location and extent of cavities. Empirical design methods and local construction techniques have been successfully used such as: (i) bridging limestone cavities and slabs by filling with concrete, (ii) utilizing numerous small diameter high yield stress piles to distribute the loads and to withstand high driving stresses, (iii) filling cavities with concrete, and (iv) using micropiles to redistribute the loads. Two case histories are presented, consisting of an access ramp and a tall building. In each of these case histories, the soil investigation methods, the pile bearing capacity calculations, the selection of pile types, the pile load tests, the pile driving criteria, and construction problems are outlined and discussed. The pile foundation used consisted of H-section, high yield stress, 355 × 368 mm, driven steel piles with capacities of 750 kN to 1280 kN for the access ramp structures and the same H-section steel piles with pile capacities of 965 kN to 1070 kN for the tall building.
Karoo igneous activity, and the early stages of the break-up of Gondwanaland
Authors: Cox K. G. 
Published: September 2007

Abstract
The widespread early Jurassic Karoo vulcanism of southern Africa appears to have been generated from a large-scale mantle plume originating in the sub-lithospheric mantle, but with a considerable additional contribution in some areas of material from the lithosphere. Subduction-related vulcanism may also play a significant role, but the relationships of the two types of vulcanism, if indeed a clear distinction does exist, are at present uncertain. Continental break-up probably took place in two stages, the first of which, in the early Jurassic, was not accompanied by true seafloor spreading. In this stage, the reactivation of an ancient shear zone is thought to have resulted in the movement of Antarctica north-eastwards relative to Africa (in the present-day African reference frame), with the creation of a zone of thinned continental crust, or a mixed zone of oceanic and continental crust, in Mozambique. The second stage took place 10–30 Ma later as Antarctica and Madagascar moved southwards relative to Africa with the formation of the oldest-known oceanic crust of the Indian Ocean.
Jurassic magmatism and tectonism associated with Gondwanaland break-up: an Antarctic perspective
Authors: Elliot David H. 
Published: September 2007

Abstract

Magmatic and tectonic activity in Antarctica associated with the early stages of continental rifting and break-up of Gondwanaland culminated with tholeiitic magmatism at about 175–180 Ma. In the Ross Sea sector of the Transantarctic Mountains, Jurassic igneous rocks, comprising pyroclastic rocks and Ferrar Group tholeiitic basalts, overlie fluvial strata of the Permian-Upper Triassic Gondwana sequence. Petrological, structural and volcanological data suggest that the Jurassic pyroclastic rocks and overlying flood basalts were erupted into a volcano-tectonic rift system associated with lithospheric extension and decompression melting. Geochemically the Ferrar tholeiites form part of the Gondwana low-Ti province, but they exhibit marked differences in initial
87
Sr/
86
Sr ratios and in high field strength element abundances in comparison with other parts of the province.

Three Early to Middle Jurassic tectono-magmatic terrains were present in this part of Gondwanaland: a plate margin magmatic arc; a belt of silicic within-plate igneous rocks inboard of the arc; and a continental flood basalt province (the Gondwana low-Ti province). Silicic volcanism mainly preceeded emplacement of Ferrar tholeiites, whereas major silicic activity elsewhere either accompanied basaltic magmatism or, though spatially separated preceded it. Younger magmatic episodes have obscured much of the plate margin record. Lack of reliable age determinations makes details of relations between tectonism and magmatism difficult to assess.
Timing and duration of Early Tertiary volcanism in the North Atlantic: new evidence from West Greenland
Authors: Larsen Lotte M. , Pedersen Asger K. , Pedersen Gunver K. , Piasecki Stefan 
Published: September 2007

AbstractMarine mudstones intercalated with Early Tertiary volcanic hyaloclastites in West Greenland contain dinoflagellate cyst assemblages corresponding to nanoplankton zones NP4-NP8 (Danian to Thanetian). Sediments correlated with NP3 are known from the bottom of the volcanic sequence, whereas the top of the sequence is non-marine. A horizon with normally-magnetized subaerial lavas correlates with hyaloclastites within the NP4 interval. This horizon must correspond to magnetic polarity zone 27N; the overlying reversely-magnetized lavas are assumed to belong to both polarity zones 26R and 25R. The main plateau-building volcanic phase in West Greenland is thereby constrained between ‘top polarity chron C28N’ and ‘top polarity chron C25R’, a time interval of 5–6 Ma.In comparison with other parts of the North Atlantic Tertiary Igneous Province, the volcanism in West Greenland started at an early stage, and the main plateau-building phase was finished before the volcanism in East Greenland started in the NP9 interval (C24R). Sea-floor formation and onshore picrite volcanism started almost simultaneously within a region; first along the West Greenland margin and later along the East Greenland margin. In terms of an impinging mantle plume in the North Atlantic, the volcanism started over the peripheral parts and not over the central part. The differences in timing and character of the volcanic products in the North Atlantic indicate a considerable lithospheric control. The early, picrite-dominated volcanism in West Greenland may be caused by channelling of hot material from the axial part of the plume, impinging on a thick Archaean lithosphere beneath central to eastern Greenland, towards the west into a pre-existing lithospheric ‘thinspot’. The switch of the onshore volcanism from West to East Greenland may be caused by a concomitant switch of the hot axial plume flow from west to east because of the westwards drift of the plate over the plume.
Right place, wrong time: anomalous post-rift subsidence in sedimentary basins around the North Atlantic Ocean
Authors: Joy Aidan M. 
Published: September 2007

Abstract
The central and northern North Sea Basin was formed as a result of at least two extensional episodes, the latest of which took place during the Late Jurassic. During the Early Tertiary, some 80 Ma later, the basin experienced a dramatic acceleration in subsidence. Subsidence acceleration of Early Tertiary age has also been reported from a number of other extensional basins, on both sides of the North Atlantic, in which stretching had ceased several tens of millions of years previously. This phenomenon is not in agreement with the published models of extensional basin formation, which predict that the rate of thermal subsidence should progressively decline following extension. It is possible that the predicted pattern of thermal subsidence was obscured by the effects of a mantle hot spot beneath the North Atlantic lithosphere during the Cretaceous to Early Tertiary. However, it is difficult to explain the subsidence phenomena observed in basins around the North Atlantic Ocean using simple hot spot models. It is concluded that the relationships between hot spot activity, continental break-up and vertical crustal movements in the North Atlantic region are subtle and complex, but that subsidence history analysis can yield valuable insights into these relationships.
Geochronologies and environmental records of Quaternary fluvial sequences in the Guadalope basin, northeast Spain, based on luminescence dating
Authors: Fuller Ian C. , Macklin Mark G. , Passmore David G. , Brewer Paul A. , Lewin John , Wintle Ann G. 
Published: September 2007

AbstractGeomorphological investigations of Quaternary fluvial deposits in the Guadalope basin, NE Spain, have revealed an extended record of river and drainage basin response to long term environmental change. Investigations have focused on a 13 km long reach centred on the town of Castelserás and a 4 km long reach at Mas de Las Matas. The study reach at Mas de Las Matas is located at the confluence of the Rio Guadalope and its principal tributary the Rio Bergantes. The Castelserás reach is situated 16 km downstream from the Bergantes confluence within a relatively narrow bedrock-confined valley.Luminescence dating provides a geochronology indicating that deposits in both study reaches span the Mid-Pleistocene through to the historic period. The Mid-Pleistocene was characterized by large-scale (locally up to 40 m) aggradation and incision cycles associated with tributary stream and slope input of sediment. More gradual alluviation in oxygen isotope stages 4 and 5 was followed by renewed dissection and aggradation immediately preceding the Last Glacial Maximum. At least four river terraces were formed during this period, with heights above present river level of between 10 and 15 m. River instability continued after the glacial maximum and into the Holocene, when the most recent major alluvial unit was formed 3000 to 5000 years ago.Progressive entrenchment of the Guadalope valley floor during the Pleistocene would appear to reflect long-term regional uplift with channel aggradation and dissection episodes linked to the climate changes shown by vegetation and oxygen isotope records. Rates of downcutting increased during oxygen isotope stages 2 and 3. This change probably occurred in response to a reduction of coarse sediment delivery to the main channel from tributary catchments, an increase in trunk stream competence and/or catchment uplift.
Magnitude and frequency of Holocene palaeofloods in the southwestern United States: A review and discussion of implications
Authors: Enzel Yehouda , Ely Lisa L. , House P. Kyle , Baker Victor R. 
Published: September 2007

Abstract
Data about the magnitude and time of occurrence of palaeofloods from the lower Colorado River basin enable us to test two long-standing hypotheses which have affected many studies and applications in the field of flood hydrology. The two hypotheses are (a) the existence of an upper boundary to flood magnitudes and whether there is a possibility of determining it from the existing data, and (b) the random occurrence versus clustering of the large floods through time.
Earlier observations on regional flood envelope curves indicated the existence of an upper limit for flood magnitudes, but these studies limited their conclusions because of the short length of the systematic gauged data. This limitation is overcome here because palaeoflood data cover a much longer period of observation. Palaeoflood studies provide information about the largest individual floods experienced in many rivers in a specific region occurring over the last millennia. In the southwestern US, this information demonstrates that, even when the length of observational data increases to centuries and millennia, there is no change in the stabilized, regional envelope curves constructed from gauged and historical flood records. This pattern supports the hypothesis of an upper limit to flood magnitudes and points to a method for testing this hypothesis in other regions. There are surprising similarities between the envelope curve of the palaeoflood data and the envelope curve for the gauged and historical data in the lower Colorado River basin. These similarities indicate that in regions of the world where flood data is sparse envelop curves based on palaeoflood studies can provide basic data for engineering design purposes and other hydrological applications.
The random occurrence of large floods in time is tested by constructing chronologies for the largest palaeofloods in several basins in the lower Colorado River basin. These chronologies indicate a clustering of the large floods in specific time periods. The similarity between the various time periods characterized by high- and low-flooding and other palaeoclimatic indicators from the southwestern United States seems best explained by a climatic control on flood frequency over the last 5000 years.
Late Quaternary intra-continental river palaeohydrology and polycyclic terrace formation: the example of south Siberian river valleys
Authors: Yamskikh A. F. 
Published: September 2007

Abstract
The subject of intra-continental river regime and related polycyclic terrace formation has been investigated in south and central Siberia. The intra-continental river regime in the past has differed from the regimes of regions with both marine dominated climates and marine/continental transitional climates. The main feature of the intra-continental paleohydrological river regime was extremely high increases in river level. These increases in level were caused by periodic increases of river discharge during the Pleistocene and Holocene which occurred during periods of valley relief instability caused by climate cooling. The simultaneous accumulation of alluvium on surfaces of different heights occurred during high floods and caused the formation of polycyclic terraces. These are the type terraces of the intra-continental regions.
River responses to decadal-scale changes in discharge regime: the Gila River, SE Arizona
Authors: Hooke J. M. 
Published: September 2007

Abstract
Rapid and large responses of semi-arid fluvial systems to alterations in discharge are well documented. Some of these changes have been sudden and have resulted in ‘metamorphosis’ of the channel. The Gila River in SE Arizona, USA, was identified as behaving in this way in the early twentieth century. Changes of the Gila River channel since 1920 have been investigated, and in particular, the last three relatively wet decades have been compared with the drier ones of the 1920s to 1950s. The research has shown that the morphological response to high flow events depends on sequences of events and critical combinations of conditions. Feedback effects of morphology can induce a ramped response and morphology can be further complicated by interactive effects with vegetation growth. Morphology may therefore not show a simple relationship to size of event or wetness of a period and therefore care should be taken when making palaeohydrological inferences from morphology.
Identifying Phanerozoic extinction controls: statistical considerations and preliminary results
Authors: Macleod N. 
Published: September 2007

AbstractTwo prominent patterns have been recognized in Phanerozoic extinction data: (1) a quasi-periodic distribution of extinction-intensity peaks, and (2) a linear, declining background extinction intensity gradient. Characterization and interpretation of both patterns are necessary to understand Phanerozoic extinction controls. The extinction-intensity peak spectrum has been variously interpreted as a reflection of the time-series of major sea-level regressions, continental flood-basalt province (CFBP) eruptions, and bolide impacts. In order to evaluate the level of association between these time-series and the Phanerozoic marine invertebrate extinction record statistically, a new Monte Carlo simulation strategy is presented. Results of simulation-based tests suggest that the time-series of major, eustatic sea-level regressions and CFBP eruption events have a statistically significant (p≤ 0.05) association with Tatarian-Pliocene, stage-level, extinction intensity peaks. Associations between this peak series and the time-series of crater-producing bolide impacts do not appear significant at this level. A limited multicausal event scenario was also tested using the Monte Carlo method, and recognized the combination of sea-level regression and CFBP volcanism to be significantly associated with the largest extinction intensity peaks of the last 250 Ma. The background extinction-intensity gradient has been interpreted variously as: (1) an indicator of progressive improvement in extinction resistance through selection; (2) the by-product of an invasion of marginal (extinction-resistant) habitats; and (3) as a taxonomic-stratigraphical artefact. Results of subdivided linear trend analyses suggest that the background extinction-intensity gradient is largely confined to the Late Palaeozoic-Cenozoic interval. No statistically significant gradient is present in the most recent compilation of Early-Middle Palaeozoic data on marine, invertebrate extinctions. The timing of gradient initiation and extinction variance analyses suggest that reorganization of global carbon cycles and oceanographical circulation patterns in the Devonian-Early Carboniferous, and the evolutionary appearance of modern phytoplankton groups in the Late Triassic both had dramatic effects on the character of the extinction-intensity gradient.
Conodont sample-population approach to defining the base of the Changhsingian Stage, Lopingian Series, Upper Permian
Authors: Mei Shilong , Henderson Charles M. , Cao Changqun 
Published: September 2007

Abstract

Conodonts have been restudied in order to define the base of the Changhsingian Stage boundary at Meishan, Changxing County, Zhejiang Province, China. The Changhsingian represents the second and last stage of the Upper Permian, which is also known as the Lopingian Series. A sample-population based taxonomic approach has been used and described. This approach usually views the entire collection within a given sample as a population and recognizes the most consistent and stable characters within that ‘sample-population’ for identification. Three related conodont species,
Clarkina longicuspidata
Mei & Wardlaw
in
Mei
et al.
1994,
C. wangi
(Zhang 1987) and
C. subcarinata
(Sweet
in
Teichert
et al.
1973) have been redefined and redescribed using this new approach that recognizes carinal development as an apomorphic character for these taxa. A consistent change in denticulation has been observed between
Clarkina longicuspidata
and
Clarkina wangi
wherein
C. longicuspidata
has a prominent gap in front of the cusp, whereas
C. wangi
has a ‘wall’-like carina. The carinal change may have resulted from a heterochronic process involving acceleration, since juvenile descendants exhibit features of ancestral adults; the change may be related to the evolution of other biota that may represent potential food sources for the conodont animal, given the apparent importance of the conodont carina for food processing. It is suggested that the base of the Changhsingian Stage could be defined within the
C. longicuspidata-C. wangi
lineage, based on the newly refined taxonomy. This boundary occurs close to the flooding surface that represents at least the second parasequence within the Changxing Limestone. The proposed boundary is close to, but not identical with, the traditionally defined boundary.
Early-Middle Pleistocene deep circulation in the western subtropical Atlantic: southern hemisphere modulation of the North Atlantic Ocean
Authors: Ferretti P. , Shackleton N. J. , Rio D. , Hall M. A. 
Published: September 2007

AbstractEarly-Middle Pleistocene climate and deep ocean hydrography have been reconstructed using oxygen and carbon isotope ratio measurements in planktonic and benthic foraminifera from a high-deposition-rate sedimentary succession recovered at the Bermuda Rise, in the northern Sargasso Sea (Ocean Drilling Program Leg 172, Site 1063). The site’s water depth makes it sensitive to changes in the balance between North Atlantic Deep Water (NADW) and Antarctic Bottom Water (AABW) in the deep North Atlantic, allowing the evaluation of perturbations in deep water production at different timescales. Millennial-scale fluctuations, superimposed on the longer period oscillations of orbital origin, occurred during all the observed climate states. The highest amplitude sub-Milankovitch fluctuations were mainly associated with interglacials, particularly after the intensification of the glacial regime atc.900 ka. Using the benthic carbon isotope signal as a water mass tracer, and by comparing the δ13C record to a suite of drill sites in the North Atlantic and Pacific oceans, it has been possible to infer that the relative strength of AABW production varied through time, as did that of NADW. A scenario in which the two different source components of deep water can undergo dramatic changes in their circulation regime through time should be taken into consideration when evaluating the role of thermohaline circulation in global climate change.
pH Mapping of Localized Corrosion in Confined Electrolytes by Total Internal Reflection Fluorescence Microscopy
Authors: Loete Florent , Vuillemin Bruno Vuillemin , Oltra Roland 
Published: September 2007

A device for pH mapping derived from optical sensors similar to TIRFM (Total Internal Reflection Fluorescence Microscopy) has been developed for future possible applications in the field of localized corrosion. The basic principle of this sensor is based on the excitation of a fluorescent silica polymer film of nanometer dimensions, deposited by sol-gel method on a waveguiding layer.	Using this sensor as a crevice former the pH changes have been recorded for a cavity machined in a Fe-17%Cr electrode for different sizes of gap.
Predicting Charge-Times of Internal Cardioverter Defibrillators
Authors: Gomadam Parthasarathy M. , Brown Jason , Scott Erik , Schmidt Craig 
Published: September 2007

A novel method of validation of the mathematical model for batteries that power Medtronic's Implantable Cardioverter Defibrillators (ICDs) is presented. In a conventional approach used in the past, the model has been validated against data collected in controlled laboratory conditions.	To supplement this approach, we now validate the model against ICD performance data reported from devices used in the field for periods ranging from about five to seven years. The key model output is ICD charge time - the time required to charge a high voltage capacitor in preparation to deliver shock to the heart.	This validation is carried out for five of Medtronic's ICD designs and very close agreement is obtained between model predictions and field data.
Electrochemical Studies of Rose Bengal Using the Electrochemical Quartz Crystal Microbalance
Authors: Andrieux Fabrice P. , Boxall Colin 
Published: September 2007

We present the results of an Electrochemical Quartz Crystal Microbalance study of the dark electrochemical behavior of rose bengal on gold piezoelectrodes in phosphate buffer at pH=7. Five oxidation and two reduction peaks were identified. The first oxidation process (Epox1=0.52V) is attributed to the formation of a Charge Transfer Complex (CTC) of rose bengal. The second process (Epox2=0.76V) is due to the partial breakdown of that CTC. The third process (Epox3=1.12V) is the electrochemical formation of a rose bengal polymer. Peak four (Epox4=1.24V) is due to the electrochemistry of the underlying	gold surface, whilst peak five (Epox5=1.45V) is attributed to a process that facilitates trans-passive polymerization. The first reduction peak (Epred1=0.42V) is due to gold oxide stripping and the second (Epred2=0.36V) is the reduction of	residual charge transfer complex formed in the first oxidation	process.