bluuebunny/crossref_metadata_2025 huggingface dataset:
DAMAGE DETECTION OF TRUSS-LIKE STRUCTURES USING WAVELET TRANSFORMS
Authors: WANG GAO-PING , HONG YONG , HONG DONG-PYO , KIM YOUNG-MOON
Published: May 2008

This study deals with the application of wavelet transforms to the damage detection of truss-like structures. The principles of damage detection by using the wavelet transforms are interpreted and the damage detection capabilities of wave transforms for cracks are demonstrated by numerical and experimental methods. Numerical simulation in combination with the wavelet transforms provides reliable numerical results and the guided wave method using smart materials enables the experimental verification of the numerical results. The basic component elements of truss structures, i.e., beams, are studied first, and subsequently complex structures are considered. The information extracted from the simulation data by using the wavelet transforms shows considerably accurate signatures for localization of damages. In particular, the study considers the influence of structural discontinuities and loading points on damage detection of crack localization. The information extracted from the signal by using the numerical and experimental methods employing the wavelet transforms shows the robustness of the methods in detecting damages in simple and complex structures.
ASSESSMENT OF LOCAL STIFFNESS FOR SLENDER CONCRETE MEMBERS USING IMPULSE RESPONSE TEST
Authors: LAI JIUNNREN , YU CHIH-PENG , CHENG CHIA-CHI
Published: May 2008

In a typical dynamic test of structural members, signals within low frequency range can normally reflect the overall stiffness of the member, while they seem not useful in assessing stiffness of a specific region. In this study, a simple back-calculation procedure was developed to potentially assess quasi-static stiffness for a specific portion of a linear member. The purpose of this study is to briefly introduce the theoretical background of such methodology and to verify the feasibility of such procedures with experimental data obtained from tests on concrete specimens. Based on the numerical and experimental data, it was found that the proposed method gives reasonable estimates of stiffness for the test portion of a symmetric reinforced concrete beam. Certain modifications are also required in extending such procedures to members with various boundary conditions.
A SIMPLIFIED 8 × 8 TRANSFORMATION AND QUANTIZATION REAL-TIME IP-BLOCK FOR MPEG-4 H.264/AVC APPLICATIONS: A NEW DESIGN FLOW APPROACH
Authors: AMER IHAB , BADAWY WAEL , JULLIEN GRAHAM , MATTAVELLI MARCO , TURNEY ROBERT
Published: May 2008

Current multimedia design processes suffer from the excessively large time spent on testing new IP-blocks with references based on large video encoders specifications (usually several thousands lines of code). The appropriate testing of a single IP-block may require the conversion of the overall encoder from software to hardware, which is difficult to complete in the short time required by the competition-driven reduced time-to-market demanded for the adoption of a new video coding standard. This paper presents a new design flow to accelerate the conformance testing of an IP-block using the H.264/AVC software reference model. An example block of the simplified 8 × 8 transformation and quantization, which is adopted in FRExt, is provided as a case study demonstrating the effectiveness of the approach.
MISS RATIO IMPROVEMENT FOR REAL-TIME APPLICATIONS USING FRAGMENTATION-AWARE PLACEMENT
Authors: ELFARAG AHMED A. , El-BOGHDADI HATEM M. , SHAHEEN SAMIR I.
Published: May 2008

Partially reconfigurable field-programmable gate arrays (FPGAs) allow parts of the chip to be configured at runtime where each part could hold an independent task. Online placement of these tasks result in area fragmentation leading to poor utilization of chip resources.

In this paper, we propose a new metric for measuring area fragmentation. The new fragmentation metric gives an indication to the continuity of the occupied (or free) space and not the amount of occupied space. We show how this metric can be extended for multidimensional structures. We also show how this metric can be computed efficiently at runtime. Next, we use this measure during online placement of tasks on FPGAs, such that the chip fragmentation is reduced. Our results show improvement of chip utilization when using this fragmentation aware placement method over other placement methods with well-known bottom left, first fit, and best-fit placement strategies. In real-time environment, we achieve an improvement in miss ratio when using the fragmentation-aware placement over the bottom left placement strategy.
A PLATFORM APPROACH FOR HARDWARE/SOFTWARE CO-DESIGN WITH SUPPORT FOR RTOS-BASED SYSTEMS
Authors: El-MALAKI M. H. , El-KHARASHI M. WATHEQ , HAMMAD S. , SALEM A. , WAHDAN A.
Published: May 2008

We propose a new flow for hardware/software co-design, based on the platform-based design, which forms a base for further automation attempts of the co-design process. We prove the applicability of the proposed flow on co-designing generic systems as well as RTOS-based systems. Our proposed flow starts with a software-only solution in which all system functionality is described as embedded software targeting a selected platform. Then, the flow iterates through co-verification, profiling, partitioning, and co-synthesis until the design criteria are met. We present four test cases to show the effectiveness of our proposed methodology. The main contribution added by the proposed methodology is incorporating the target application platform at the first stage of the flow then applying our iterative co-design algorithm without altering the main platform. This opposes other co-design methodologies that let the platform details be synthesized at later stages, widening the exploration space to be unrealistic and producing platforms that may vary to a large extent compared to the pre-verified application platform. The other contribution is the study provided on the effect of co-design on the behavior of RTOS-based platforms, which brings the flow closer to real-case problems, where most embedded systems utilize RTOS in their software stack.
QUEUE MODELING AND IMPLEMENTATION FOR NETWORKS-ON-CHIP ROUTERS
Authors: ELMILIGI HAYTHAM , El-KHARASHI M. WATHEQ , GEBALI FAYEZ
Published: May 2008

Queue modeling is an important step in Networks-on-Chip (NoC) design to understand and estimate the system behavior at early design phases. Choosing queue parameters, such as queue size, maximum packet arrival rate, packet service rate, directly impacts the performance and silicon area of the overall NoC-based design. In this paper, we propose a new 2D M/D/1/B queuing model for NoC routers. Using our model, we prove that packet service rate impacts throughput significantly. On the other hand, changing the queue size, within acceptable ranges for NoC applications, does not have a noticeable effect on the throughput. Through a case study implementation on FPGA, we explain how this model could be used in different applications to obtain design parameters at higher levels of abstraction. Synthesis and performance analysis are performed to validate the proposed model.
GMR- AND GMI-BASED SYSTEMS FOR NONDESTRUCTIVE EVALUATION OF PRINTED CIRCUIT BOARD
Authors: ELSHAFIEY IBRAHIM , MOHRA ASHRAF
Published: May 2008

Advances in magnetoresistive type sensors provide a new technique for nondestructive evaluation of metal structures. Giant magnetoresistive and giant magnetoimpedance sensors provide high sensitivity and reduced size with GMI sensors also adding capabilities of high frequency range of measurements. Being produced with thin film processing techniques, the manufacturing cost of these sensors is low. An example is considered of detecting defects in printed circuit boards. System details and experimental results are provided. Computational modeling validation is introduced based on finite element as well as method of moments analysis.
TOWARD A MINIATURIZED GENERATION OF ULTRASONIC-BASED DEVICES
Authors: KASSEM ABDALLAH , SAWAN MOHAMAD , HAMAD MUSTAPHA , HAIDAR ALI
Published: May 2008

This paper concerns the design method and implementation of main modules, dedicated to miniaturized digital ultrasonic devices, using advanced System-on-Chip technique. It is intended to diagnostic imaging applications such as echography. The proposed implementation allows the integration of all acquisition front end as well as signal and video processing on only one single chip. It will make possible to visualize the ultrasound images in real time. It requires high resolution and real-time image processing. The proposed design, which integrates the B-mode processing modules, includes digital beamforming, quadrature demodulation of RF signals, digital filtering, envelope detection, and video processing of the received signals. This system handles 128 scan lines and 6400 samples per scan line with a 90° angle of view span. The design uses a minimum size look-up memory to store the initial scan information. Rapid prototyping based on ARM/FPGA platform combination is used to validate the operation of the described system. This system offers significant advantages of portability and a rapid time to market.
DELAY AND ENERGY EFFICIENT CODING TECHNIQUES FOR CAPACITIVE INTERCONNECTS
Authors: RAVINDRA J. V. R. , SRINIVAS M. B.
Published: May 2008

In the current era of deep-submicron technology (DSM), minimizing the propagation delay and energy consumption on buses is the most important design objective in system-on-chip (SOC) designs. In particular, coupling effects between wires on the bus can cause serious problems such as cross-talk delay, noise, and power dissipation. Most of the work reported in literature so far concentrates on either minimizing the energy consumption or the delay. In this paper, the authors propose two coding techniques for achieving energy and delay efficiency in data transmission on on-chip buses. It is shown, using SPEC 2000 benchmark suit, that the proposed techniques achieve an energy saving of 35% or over the un-encoded data on the data bus and eliminate cross-talk-delay classes 6, 5, and 4.
Permian–Triassic sedimentology of Jameson Land, East Greenland: incised submarine channels in an anoxic basin
Authors: Wignall Paul B. , Twitchett Richard J.
Published: May 2008

The presence of deeply erosive, conglomeratic sandstone-filled channels around the Permian–Triassic (P–Tr) boundary in East Greenland has been widely cited as evidence for a major, late Permian eustatic lowstand. Facies analysis of such channels and their associated strata in fact suggests that they record part of an intrinsic style of basinal deposition (that persisted into Early Triassic time). Their origin can be explained without the need to invoke eustatic sea-level fall. Active faulting and hinterland elevation is envisaged to have generated powerful sediment-gravity flows that were capable of submarine erosion of fine-grained, unconsolidated strata. Stacked, turbidite-sandstone-filled lenses also occur beneath fan delta sandbodies and probably record infill of channels or chutes cut into the subaqueous slopes of such deltas. Shale successions developed between the incised channel locations record complete P–Tr transitions in which a rapid onset of anoxic deposition is seen in latest Permian time. This is the local manifestation of a global anoxic event. Unusual aspects of the Lower Triassic sequence in Greenland include the presence of well-oxygenated intervals, stromatolite bioherms and red algae.
Palaeozoic tectonic evolution of the Middle Urals in the light of the ESRU seismic experiments
Authors: Friberg M. , Juhlin C. , Beckholmen M. , Petrov G.A. , Green A.G.
Published: May 2008

Abstract:
A new compilation of deep seismic reflection data, in combination with the results of recent geological and isotopic investigations, provides the basis for significantly refined structural and evolutionary models of the Middle Urals. Many of the major structural boundaries observed at the surface (e.g. Main Uralian Thrust, Main Uralian Normal Fault, Serov–Mauk Fault, Prianitchnikova Shear Zone) can be followed on the seismic reflection data to depths of 8–15 km. Only a few features can be traced through the horizontal to shallow dipping zones of middle-crustal reflectivity that extend beneath much of the Middle Urals. Exceptions might be the Deevo Thrust and a newly discovered deep band of moderately dipping reflections beneath the West Siberian Basin that may represent the remnants of an ancient subduction zone. The reflectivity of the lower crust and Moho are similar beneath the hinterland of the Urals and below the western part of the West Siberian Basin, suggesting that in both places they have the same extensional origin. Accretion of various exotic terranes to the eastern margin of Baltica during Late Palaeozoic time involved considerable shortening of the continental margin. The accreted terranes (e.g. Tagil, Petrokamensk and Alapaevsk Arc Complexes) consist mostly of island-arc material formed during Mid- and Late Palaeozoic time. Closely associated with the island arcs are several high-grade metamorphic complexes (e.g. Salda and Murzinka–Adui Complexes) that were exhumed during and after Late Palaeozoic convergence. Towards the end of the orogeny, several north–south-trending strike-slip faults (e.g. Sisert Fault) were active. After the orogeny, major periods of tectonism and magmatism in the Middle Urals resulted in the extrusion of the Siberian trap basalts, crustal stretching and/or underplating, and the formation of the West Siberian Basin, the planet’s largest intracontinental sedimentary basin. Finally, a period of renewed thrust faulting, often reactivating older faults, led to the inversion of the Mesozoic basins.
Widespread post-nappe normal faulting in the Internal Western Alps:a new constraint on arc dynamics
Authors: SUE C. , TRICART P.
Published: May 2008

Abstract:
Field data collected in the Briançonnais and Piémont zones at the centre of the western Alpine arc demonstrate a high density of normal faults. Normal displacements are pervasive from the millimetric to the kilometric scales. They occur both parallel and at high angles to the arc, overprinting all the Alpine folds and thrusts and the associated schistosities. The orientation of fault striae implies that the pile of metamorphic nappes SE of the Pelvoux massif has undergone a general extension. Extension tends to be multidirectional in the Briançonnais zone. Orogen-parallel extension prevails in most of the Piémont Schistes lustrés. To the west, in Briançonnais zone, brittle extension is associated with a reversal of movement along the Briançonnais Frontal Thrust that started before the end of the Oligocene. In the Piémont Schistes lustrés, the onset of normal faulting occurred early in the Miocene and continued the ductile extension that accompanied the exhumation of HP–LT metamorphic thrust sheets during the Palaeogene. In both zones, extension remains currently active, resulting in the regional seismicity. Since more than 20 Ma ago, this normal faulting in the internal arc coexists with an outward propagation of folds and thrusts in the external arc. We discuss its possible significance in the context to the dynamic evolution of the Alps.
Identifying cryptic tidal influences within deltaic successions: an example from the Marsdenian (Namurian) interval of the Pennine Basin, UK
Authors: BRETTLE M.J. , McILROY D. , ELLIOTT T. , DAVIES S.J. , WATERS C.N.
Published: May 2008

Research literature abounds on the depositional processes and products associated with macro-tidal regimes, whereas there is little available literature on sediments deposited in micro-tidal regimes. This paper presents new field-based sedimentological interpretations of the Marsdenian (Namurian, Carboniferous) interval of the Pennine Basin, a basin-fill that is classically regarded as the archetypal fluvial-dominated delta system. This paper reinterprets discrete lithostratigraphic units, and suggests they were deposited under the influence of weak tidal currents. We highlight three lithofacies that contain tidally influenced deposits within the Marsdenian interval of the Pennine Basin; a cross-bedded sandstone with mud drapes and reactivation surfaces, a heterolithic ripple-laminated sandstone with muddy drapes and silty mudstone interlaminations, and a rhythmic–parallel-bedded sandstone with mudstone–siltstone interlaminations. Evidence for cryptic tidal signatures in tractionally transported and reworked sediments is qualitative, and largely dependent on the sedimentologist's view of what constitutes a diagnostic number of tidal indicators (i.e. mud-drape couplets, reactivation surfaces). In areas away from either tractional deposition or reworking, sediments deposited from suspension are more likely to preserve indicators of tidal processes. This paper focuses on a lithofacies interpreted as a tidally influenced sand-rich delta-front mouthbar deposited from a buoyant effluent plume. Time-series analysis of laminae thickness variations in this facies implies that these variations are rhythmic. We review how the interaction of tidal currents and buoyant plume processes modifies depositional products. This model implies that the rhythmic variation observed in the Marsdenian interval is attributed to the modulation of plume deposition by tidal currents with a semi-diurnal and diurnal tidal periodicity.
Basanites related to Late Eocene extension from NE Oman
Authors: WORTHING M.A. , WILDE A.R.
Published: May 2008

Six small basanite intrusions were emplaced into the allochthonous Batain Nappes of NE Oman along approximately north–south to NNW–SSE lineaments. They contain olivine, clinopyroxene, plagioclase, analcite, ulvöspinel and apatite ± biotite ± calcite. The basanites are primitive, with Mg numbers (100Mg/(Mg + Fe
2+
)) from 63.18 to 69.37, and are nepheline normative. Compositional variation suggests fractionation of olivine and clinopyroxene. Thermobarometric studies on rare spinel lherzolite xenoliths suggests re-equilibration at shallow depth.
143
Nd/
144
Nd and
87
Sr/
86
Sr isotopic data and REE modelling indicate that the magmas were formed by 1–2% melting of an ocean-island basalt (OIB)-like source containing about 3–4% garnet. Deviations from OIB are explained by mobilization of incompatible elements from potassic layers in the lithosphere during ascent. Sedimentological studies and three new whole-rock Ar/Ar ages (39.77 ± 0.26, 37.63 ± 0.46 and 36.51 ± 0.21 Ma, Lutetian to Priabonian time) suggest intrusion during maximum deepening of the Abat Trough. Movements were related to dextral strike-slip movement along major tectonic structures during the initial stages of the opening of the Gulf of Aden. The basanites were formed by decompressional melting of an asthenospheric mantle source facilitated by thinned lithosphere and depression of the solidus by H
2
O- and CO
2
-rich fluids.
Andesite petrogenesis in the Ordovician Borrowdale Volcanic Group of the English Lake District by fractionation, assimilation and mixing
Authors: McConnell B.J. , Menuge J.F. , Hertogen J.
Published: May 2008

A suite of composite basalt–andesite dykes in the Ordovician Borrowdale Volcanic Group of the English Lake District records magmatic evolution from basalt to andesite. Although altered, the rocks preserve textures that indicate magma mixing. Primitive basalts were derived from a fertile, subduction-modified mantle source. Evolution by fractional crystallization is suggested by rapid decrease of compatible trace element concentrations and similar incompatible trace element and REE profiles throughout the sample range. Recharge of the evolving magma with fresh batches of basaltic composition is indicated by some samples that have compatible trace element concentrations much higher than expected from their otherwise evolved compositions. Geochemical evidence of magma mixing is provided by linear trends between pairs of incompatible trace elements not at constant ratio. e
Nd
values indicate addition of a crustal component, but samples do not conform to a simple mixing equation. The combined evidence points to magma evolution by assimilation of wallrock during fractional crystallization (AFC) with periodic recharge. We have modelled an AFC process using a Skiddaw Group metasediment contaminant that can explain trace element and isotopic variation through variable amounts of assimilation, crystal fractionation and recharge, to produce a spectrum of compositions that was sampled periodically by the dykes. There is evidence from other parts of the Borrowdale Volcanic Group that similar processes operated throughout its history.
Insights into orogenesis: getting to the root of a continent–ocean–continent collision, Southern Urals, Russia
Authors: Scarrow Jane H. , Ayala Conxi , Kimbell Geoffrey S.
Published: May 2008

The Ural mountains preserve a late Palaeozoic collision that forms a 2500 km suture in the world's largest landmass, Eurasia. Several features of the mountain belt, in particular a well-preserved crustal root, are uncharacteristic of other Palaeozoic orogens such as the Appalachians and Caledonides. Previous interpretations of the Southern Uralian root suggested that it is composed of East European Craton crust derived from the west. A new potential field data model, considered in conjunction with published seismic, heat-flow and geological data, indicates that the root is composed mainly of mafic granulite, which we interpret as oceanic arc crust originally accreted from the east, subducted eastward, and metamorphosed. A load caused by crustal lateral density variations, combined with topography, isostatically compensates root buoyancy and is thus the main cause of its preservation.
The nature and provenance of accreted oceanic terranes in western Ecuador: geochemical and tectonic constraints
Authors: KERR ANDREW C. , ASPDEN JOHN A. , TARNEY JOHN , PILATASIG LUIS F.
Published: May 2008

Western Ecuador consists of a complex tectonic mélange of oceanic terranes accreted to the continental margin from Late Cretaceous to Eocene time. New geochemical data from these accreted terranes (arising from a 5 year British Geological Survey mapping programme) indicate that they comprise rocks from a variety of oceanic tectonic settings: from thickened (and relatively unsubductable) oceanic plateau basalts, through island-arc tholeiites, with occasional more calc-alkaline lavas, to back-arc basin basalt sequences. This study has enabled us to construct a new geodynamic model for the Cretaceous–Tertiary evolution of the Northern Andes, and has placed important new constraints on the extent of oceanic plateau sequences in Colombia and around the Caribbean. The age and nature of sediments, combined with evidence for the age of peak metamorphism, suggests that a prolonged (15–20 Ma) accretionary event occurred in Late Cretaceous time and involved the collision of an oceanic plateau (represented by the Pallatanga Unit) with the continental margin. This accreted unit can be correlated with similar oceanic plateau sequences from the Western Cordillera of Colombia and those within and around the Caribbean region. The Naranjal and Macuchi island arcs and the associated La Portada back-arc basin developed along the accreted margin from Late Campanian to Eocene time, and these arcs accreted to the continental margin along with oceanic plateau material (represented by the Piñon Unit and Pedernales–Esmeraldas sequences) during Eocene time. The development of island arcs, which separate the two accretionary events, implies that the most westerly (coastal) oceanic plateau sequences, both in Ecuador (Piñon and Pedernales–Esmeraldas) and in Colombia (Gorgona and Serranía de Baudó), cannot belong to the Caribbean–Colombian Oceanic Plateau (CCOP). It therefore appears that at least two different oceanic plateaux are preserved within the accreted oceanic terranes of the Northern Andes. It is possible that the CCOP formed over the Galápagos hotspot, as previously proposed, but the more westerly Coastal plateau was derived from a more southerly hotspot source region, such as Sala y Gomez, in the SE Pacific.
Long-term memory of subduction processes in the lithospheric mantle: evidence from the geochemistry of basic dykes in the Gardar Province of South Greenland
Authors: Goodenough K.M. , Upton B.G.J. , Ellam R.M.
Published: May 2008

The rift-related magmas of the Proterozoic Gardar Igneous Province were emplaced across the contact between the South Greenland Archaean craton and the Palaeoproterozoic Ketilidian mobile belt. It has been suggested that the geochemistry of Gardar intrusive rocks in the two areas varies across the craton margin and that this reflects a lithospheric control. However, comparison of the geochemical and isotopic signatures of basic and ultrabasic dykes from across the area shows that there is no systematic variation related to the age of the country rock. All the Gardar basic rocks are inferred to have been derived from the mantle, with relatively little crustal contamination. We suggest that the lithospheric mantle beneath the Gardar Province was enriched by slab-derived fluids during the Ketilidian orogeny (
c
. 1800 Ma). Subsequent melting of this mantle source was promoted during Gardar rifting when volatile-rich, small-degree melts from the asthenosphere were introduced into the lithospheric mantle, forming enriched metasomites. Ultrabasic lamprophyre dykes in the Gardar Province represent melts derived largely from these metasomites, whereas basaltic magmas were formed by larger-scale melting of the lithospheric mantle, inheriting a subduction-related signature. There is no evidence that the Gardar magmas were derived from a highly enriched lithospheric keel that had existed since craton formation.
Attempted break-up of Rodinia at 850 Ma: geochronological evidence from the Seve–Kalak Superterrane, Scandinavian Caledonides
Authors: PAULSSON OSKAR , ANDRÉASSON PER-GUNNAR
Published: May 2008

Lower thrust sheets of the Scandinavian Caledonides derive from the margin of Baltica, which was imbricated during Early Palaeozoic closure of oceans formed during separation of the Baltica, Laurentia and Siberia cratons. At Vistas (Kebnekaise Mts), the Seve Nappe Complex preserves rare lenses of a dolerite-intruded granite formed by anatexis during emplacement of gabbro into metasedimentary rocks. Ion microprobe U–Pb dating of prismatic zircons from the granite yielded an age of 845 ± 14 Ma (mean square weighed deviation (MSWD) 1.15), interpreted to date magmatic crystallization. Cores of complex crystals indicate protolith ages of 1778 ± 11 Ma (MSWD 0.86); one core yielded an Archaean age. From narrow rims, a 605 ± 42 Ma metamorphic age is obtained, and is interpreted to reflect the emplacement of the extensive Vendian rift magmatic dolerite dyke swarm. The age pattern allows correlation with a previously dated magmatic complex within the equivalent Kalak Nappe Complex 300 km to the north. Bimodal magmatic complexes with this age pattern do not occur within the basement of the Caledonide foreland, nor elsewhere within the Baltic Shield. However, recent reinterpretations of the Knoydartian event in Scotland as rift related invites correlation with the West Highland Granite Gneiss, which intruded Moine metasedimentary rocks at
c
. 870 Ma. In Central Taimyr, 850–900 Ma granites of continental crustal derivation and with 1800–1900 Ma Sm–Nd model age occur associated with
c
. 740 Ma plagiogranites. Using recent palaeogeographical reconstructions, we interpret the evidence of 850–900 Ma magmatism in Scandinavia, Scotland and Taimyr as bimodal rift magmatism in connected arms during an attempted break-up of Rodinia.
The role of the Early Tertiary Ulukisla Basin, southern Turkey, in suturing of the Mesozoic Tethys ocean
Authors: Clark Matthew , Robertson Alastair
Published: May 2008

The Maastrichtian–Late Eocene Ulukisla Basin is representative of the tectonic and sedimentary evolution of prominent Early Tertiary basins in central Anatolia, including the Tuzgölü and Şarkışla basins. The Ulukisla Basin overlies an ophiolitic mélange of Late Cretaceous age between the Bolkar Carbonate Platform to the south and the Nigde–Kırşehir metamorphic massif to the north. The basin stratigraphy records successive phases of transgression, subsidence, volcanism, evaporite deposition, deformation and uplift. Subsidence curves are consistent with an extensional (or transtensional) basin origin terminated by uplift. The Ulukisla Basin includes a thick succession (
c
. 2 km) of Upper Paleocene–Lower Eocene basaltic to andesitic submarine pillow lavas, lava flows, volcaniclastic rocks and intercalated limestones. Whole-rock XRF chemical analysis indicates a within-plate origin, with a marked subduction influence, believed to be inherited rather than contemporaneous. The Ulukisla Basin formed after Late Cretaceous ophiolite and mélange emplacement and ended with Late Eocene emergence, deformation and onset of Oligo-Miocene non-marine deposition. We propose that Late Cretaceous ophiolite and mélange emplacement reflect initial ocean basin closure. This was followed by a long period (
c
. 30 Ma) of microcontinental adjustment, including possible strike-slip, palaeorotation and suture tightening, during which the Early Tertiary Ulukisla Basin developed. Possible driving forces were regional slab pull (of a relict subduction zone) or oblique (diachronous) convergence. Suture tightening was complete by Late Eocene time marked by collisional deformation and regional uplift.
Mechanisms and controls on the formation of sand intrusions
Authors: JOLLY RICHARD J. H. , LONERGAN LIDIA
Published: May 2008

Sandstone intrusions are found in all sedimentary environments but have been reported most commonly from deep-water settings. They also appear to be more frequently developed in tectonically active settings where applied tectonic stresses facilitate development of high fluid pressures within the sediments. A variety of mechanisms have been cited as triggers for clastic intrusions. These include seismicity induced liquefaction, application of tectonic stresses, excess pore fluid pressures generated by deposition-related processes and the influx of an overpressured fluid from deeper within the basin into a shallow sand body. The formation of sandstone dykes and sills is investigated here by considering them as natural hydraulic fractures. When the seal on an unconsolidated, overpressured sand body fails the resulting steep hydraulic gradient may cause the sand to fluidize. The fluidized slurry can then inject along pre-existing or new fractures to form clastic intrusions. The scale and the geometry of an intrusive complex is governed by the stress state, depth and pre-existing joints or faults within the sedimentary succession, as well as the nature of the host sediments. For the simplest tectonic setting, where the maximum stress in a basin is vertical (gravitational loading), small irregular intrusions commonly result in the formation of sills at shallow depths within a few metres of the surface, whereas at greater depth dykes and sills forming clastic intrusion networks are more typical. A simple relationship is derived to calculate the maximum burial depth at which a dyke–sill complex forms as a function of the source-bed to sill height, the bulk density of the surrounding sediments, and the ratio of the vertical to horizontal effective stresses,
K
0
. When applied to three examples of large-scale dyke–sill complexes developed within Paleocene and Eocene deep-water reservoir sand bodies of the North Sea, maximum burial depths in a range of 375 to
c
. 500 m, 450–700 m and 550–850 m are estimated for intrusion of each of the three complexes.
Carbon isotope excursions and sea-level change: implications for the Frasnian–Famennian biotic crisis
Authors: CHEN DAIZHAO , TUCKER MAURICEE. , SHEN YANAN , YANS JOHAN , PREAT ALAIN
Published: May 2008

New carbon and oxygen isotope data from carbonates spanning the Frasnian–Famennian (F–F) boundary in the Guilin area, South China, show a broad positive
δ
13
C rise and fall, with sharp, short-lived negative
δ
13
C events; this pattern is comparable to that in Europe and North America. The integration of the isotope stratigraphy with high-resolution sequence stratigraphy corroborates the onset of the positive
δ
13
C excursion during a third-order sea-level fall in the latest Frasnian. This can best be explained through increased burial of C
org
during the sea-level fall, brought about by increased organic productivity caused by increased continent-derived nutrient flux to the ocean due to enhanced weathering through the proliferation of land plants in the Devonian. This scenario would have resulted in anoxic and eutrophic conditions over epicontinental seas and blooms of cyanobacteria, creating a highly stressful and fragile ecosystem for oligotrophic normal-marine benthic organisms and leading to their massive decline. The global third-order sea-level fall near the end of the Frasnian may have led to gas hydrate dissociation (giving the negative
δ
13
C events), and caused wild climatic fluctuations. The subsequent short-term events of sea-level rise, anoxia and eutrophication in the latest part of the F–F transition would have placed additional environmental stresses on the already weakened biota, leading to their further demise.
The rise and fall of the Faroe–Shetland Basin: evidence from seismic mapping of the Balder Formation
Authors: SMALLWOOD JOHN R. , GILL CAROLINE E.
Published: May 2008

Seismic mapping of the Faroe–Shetland Basin from three-dimensional surveys provides striking evidence for uplift of the southern Faroe–Shetland Basin in the late Palaeocene and rapid subsidence in the early Eocene. The seismic reflector at the base of the Balder Formation follows a regional unconformity surface, which records erosion of a major branching drainage network into the underlying Palaeocene section, following a major base level fall. The topography of this surface was subsequently in-filled following marine transgression, and deep-water conditions returned to the basin in the early Eocene. We attribute base level changes to the influence of the proto-Iceland mantle plume beneath the lithosphere, providing support until continental break-up west of the Faroe Islands.
The structural geometry, metamorphic and magmatic evolution of the Everest massif, High Himalaya of Nepal–South Tibet
Authors: SEARLE M.P. , SIMPSON R.L. , LAW R.D. , PARRISH R.R. , WATERS D.J.
Published: May 2008

This paper presents a new geological map together with cross-sections and lateral sections of the Everest massif. We combine field relations, structural geology, petrology, thermobarometry and geochronology to interpret the tectonic evolution of the Everest Himalaya. Lithospheric convergence of India and Asia since collision at
c.
50 Ma. resulted in horizontal shortening, crustal thickening and regional metamorphism in the Himalaya and beneath southern Tibet. High temperatures (>620 °C) during sillimanite grade metamorphism were maintained for 15 million years from 32 to 16.9 ± 0.5 Ma along the top of the Greater Himalayan slab. This implies that crustal thickening must also have been active during this time, which in turn suggests high topography during the Oligocene–early Miocene. Two low-angle normal faults cut the Everest massif at the top of the Greater Himalayan slab. The earlier, lower Lhotse detachment bounds the upper limit of massive leucogranite sills and sillimanite–cordierite gneisses, and has been locally folded. Ductile motion along the top of the Greater Himalayan slab was active from 18 to 16.9 Ma. The upper Qomolangma detachment is exposed in the summit pyramid of Everest and dips north at angles of less than 15°. Brittle faulting along the Qomolangma detachment, which cuts all leucogranites in the footwall, was post-16 Ma. Footwall sillimanite gneisses and leucogranites are exposed along the Kharta valley up to 57 km north of the Qomolangma detachment exposure near the summit of Everest. The amount of extrusion of footwall gneisses and leucogranites must have been around 200 km southwards, from an origin at shallow levels (12–18 km depth) beneath Tibet, supporting models of ductile extrusion of the Greater Himalayan slab. The Everest–Lhotse–Nuptse massif contains a massive ballooning sill of garnet + muscovite + tourmaline leucogranite up to 3000 m thick, which reaches 7800 m on the Kangshung face of Everest and on the south face of Nuptse, and is mainly responsible for the extreme altitude of both mountains. The middle crust beneath southern Tibet is inferred to be a weak, ductile-deforming zone of high heat and low friction separating a brittle deforming upper crust above from a strong (?granulite facies) lower crust with a rheologically strong upper mantle. Field evidence, thermobarometry and U–Pb geochronological data from the Everest Himalaya support the general shear extrusive flow of a mid-crustal channel from beneath the Tibetan plateau. The ending of high temperature metamorphism in the Himalaya and of ductile shearing along both the Main Central Thrust and the South Tibetan Detachment normal faults roughly coincides with initiation of strike-slip faulting and east–west extension in south Tibet (<18 Ma).
Coalitions
Authors: Humphreys Macartan
Published: May 2008

The game theoretic study of coalitions focuses on settings in which commitment technologies are available to allow groups to coordinate their actions. Analyses of such settings focus on two questions. First, what are the implications of the ability to make commitments and form coalitions for how games are played? Second, given that coalitions can form, which coalitions should we expect to see forming? I examine classic cooperative and new noncooperative game theoretic approaches to answering these questions. Classic approaches have focused especially on the first question and have produced powerful results. However, these approaches suffer from a number of weaknesses. New work attempts to address these shortcomings by modeling coalition formation as an explicitly noncooperative process. This new research reintroduces the problem of coalitional instability characteristic of cooperative approaches, but in a dynamic setting. Although in some settings, classic solutions are recovered, in others this new work shows that outcomes are highly sensitive, not only to bargaining protocols, but also to the forms of commitment that can be externally enforced. This point of variation is largely ignored in empirical research on coalition formation. I close by describing new agendas in coalitional analysis that are being opened up by this new approach.
Deliberative Democratic Theory and Empirical Political Science
Authors: Thompson Dennis F.
Published: May 2008

Although empirical studies of deliberative democracy have proliferated in the past decade, too few have addressed the questions that are most significant in the normative theories. At the same time, many theorists have tended too easily to dismiss the empirical findings. More recently, some theorists and empiricists have been paying more attention to each other's work. Nevertheless, neither is likely to produce the more comprehensive understanding of deliberative democracy we need unless both develop a clearer conception of the elements of deliberation, the conflicts among those elements, and the structural relationships in deliberative systems.
Aldosterone, but not angiotensin II, increases profibrotic factors in kidney of adrenalectomized stroke-prone spontaneously hypertensive rats
Authors: Chun Tae-Yon , Chander Praveen N. , Kim Jong-Won , Pratt J. Howard , Stier Charles T.
Published: May 2008

An increase in angiotensin II (ANG II) under conditions of high salt intake can result in renal damage. The extent to which ANG II does this directly or by way of stimulating aldosterone (Aldo) secretion is a subject of some debate. In the present study, we sought to determine the separate effects of Aldo and ANG II on the expression of plasminogen activator inhibitor-1 (PAI-1) and other factors related to renal fibrosis in the stroke-prone spontaneously hypertensive rat (SHRSP). Saline-drinking male SHRSPs underwent adrenalectomy (ADX) or sham operation (Sham). Treatment groups consisted of ADX + ANG II (25 ng/min sc) and ADX + Aldo (40 μg·kg−1·day−1sc). After 2 wk of treatment, circulating Aldo levels were reduced to the limit of detection, renal PAI-1, transforming growth factor-β1 (TGF-β1), and osteopontin expression, and phospho-Smad2 (p-Smad2) level were decreased severalfold, and Smad7 (an inhibitory regulator of TGF-β1 action) expression was increased in ADX compared with Sham rats. Infusion of Aldo into ADX SHRSPs restored the renal mRNA expression of PAI-1, TGF-β1 (along with restored p-Smad2 level), and osteopontin and reduced that of Smad7, whereas ANG II had no or a lesser effect. The findings were confirmed by histological examination of renal tissue. In summary, in the saline-drinking SHRSP, Aldo increased renal profibrotic factors and produced renal injury whereas ANG II in the absence of the adrenals had no effect.
Kinase-specific responsiveness to incremental contractile activity in skeletal muscle with low and high mitochondrial content
Authors: Ljubicic Vladimir , Hood David A.
Published: May 2008

Muscle contractions activate protein kinases, leading to signal transduction. We hypothesized that kinase activation would be influenced by mitochondrial content, as well as by contractile activity-induced increases in muscle O2consumption (V̇o2). Kinase phosphorylation in high-oxidative red and low-oxidative white tibialis anterior (TA) muscle (RTA and WTA, respectively) with 2.5-fold differences in mitochondrial content were compared. Stimulation of the TA muscle elicited large increases in V̇o2(3- to 6-fold and 4- to 60-fold above resting levels in WTA and RTA, respectively). At rest, AMP-activated protein kinase (AMPK), p38, p42, and p44 activation were nearly twofold greater in WTA than in RTA, suggesting an inverse relationship between mitochondrial content and kinase activation in resting muscle. During contractions, similar degrees of phosphorylation in RTA and WTA were evident as a function of V̇o2for p38 and p42. During increases in V̇o2up to sixfold above rest, greater responses were observed in RTA than in WTA for AMPK and p44, whereas Akt activation was greater in WTA. In RTA, elevations in V̇o2elicited increases in AMPK and p44 activation, whereas Akt, p38, and p42 were less sensitive to increments in V̇o2. Reactive oxygen species (ROS) production was greater in mitochondria from white muscle, but when it was calculated in the context of the whole muscle, ROS production was twofold greater in red than in white myofibers. Thus mitochondrial content influences ROS production and is inversely related to kinase activation in resting muscle. During contractions, kinases are differentially sensitive to contraction-induced increments in V̇o2, suggesting that muscle mitochondrial content is important, but it is not the sole determinant of kinase activation during exercise of different intensities.
Transcriptional regulation of the insulin-responsive glucose transporter GLUT4 gene: from physiology to pathology
Authors: Karnieli Eddy , Armoni Michal
Published: May 2008

The insulin-responsive glucose transporter 4 (GLUT4) plays a key role in glucose uptake and metabolism in insulin target tissues. Being a rate-limiting step in glucose metabolism, the expression and function of the GLUT4 isoform has been extensively studied and found to be tightly regulated at both mRNA and protein levels. Adaptation to states of enhanced metabolic demand is associated with increased glucose metabolism and GLUT4 gene expression, whereas states of insulin resistance such as type 2 diabetes mellitus (DM2), obesity, and aging are associated with impaired regulation of GLUT4 gene expression and function. The present review focuses on the interplay among hormonal, nutritional, and transcription factors in the regulation of GLUT4 transcription in health and sickness.
Wdnm1-like, a new adipokine with a role in MMP-2 activation
Authors: Wu Yu , Smas Cynthia M.
Published: May 2008

White adipose tissue functions in energy storage and as an endocrine organ. DNA microarray analysis led us to identify Wdnm1-like, a distant member of the whey acidic protein/four-disulfide core (WAP/4-DSC) family, as a differentiation-dependent gene in white and brown adipogenesis. Wdnm1-like is a novel 6.8-kDa protein, and Western blot analysis reveals secretion into culture media. Wdnm1-like transcript is selectively expressed in adipose tissue and liver and is enriched ∼500-fold in white adipose depots vs. brown. Cellular fractionation of WAT demonstrates Wdnm1-like transcript expression is restricted to the adipocyte population. Studies in 3T3-L1 preadipocytes, an in vitro model of white adipogenesis, indicate Wdnm1-like transcript increases within 6 h of adipogenic induction with an ∼17,000-fold increase by day 7. Dramatic upregulation of Wdnm1-like also accompanies white adipogenesis of ScAP-23 preadipocytes and primary preadipocytes. TNF-α treatment of 3T3-L1 adipocytes increased Wdnm1-like transcript level 2.4-fold and was attenuated by pretreatment with the p38 MAP kinase inhibitor SB203580. A number of WAP/4-DSC family proteins function as protease inhibitors. This, taken with the role of extracellular remodeling in adipogenesis, led us to address effects of Wdnm1-like on matrix metalloproteinase (MMP) activity. Gelatin zymography of HT1080 fibrosarcoma cells transfected with a Wdnm1-like expression construct revealed markedly increased levels of active MMP-2. Our findings identify a new member of the adipocyte “secretome” that functions to enhance MMP-2 activity. We postulate that Wdnm1-like may play roles in remodeling of the extracellular milieu in adipogenesis, as well as in tumor microenvironments where adipocytes are key stromal components.
Analysis of nonstationarity in renal autoregulation mechanisms using time-varying transfer and coherence functions
Authors: Chon Ki H. , Zhong Yuru , Moore Leon C. , Holstein-Rathlou Niels H. , Cupples William A.
Published: May 2008

The extent to which renal blood flow dynamics vary in time and whether such variation contributes substantively to dynamic complexity have emerged as important questions. Data from Sprague-Dawley rats (SDR) and spontaneously hypertensive rats (SHR) were analyzed by time-varying transfer functions (TVTF) and time-varying coherence functions (TVCF). Both TVTF and TVCF allow quantification of nonstationarity in the frequency ranges associated with the autoregulatory mechanisms. TVTF analysis shows that autoregulatory gain in SDR and SHR varies in time and that SHR exhibit significantly more nonstationarity than SDR. TVTF gain in the frequency range associated with the myogenic mechanism was significantly higher in SDR than in SHR, but no statistical difference was found with tubuloglomerular (TGF) gain. Furthermore, TVCF analysis revealed that the coherence in both strains is significantly nonstationary and that low-frequency coherence was negatively correlated with autoregulatory gain. TVCF in the frequency range from 0.1 to 0.3 Hz was significantly higher in SDR (7 out of 7, >0.5) than in SHR (5 out of 6, <0.5), and consistent for all time points. For TGF frequency range (0.03–0.05 Hz), coherence exhibited substantial nonstationarity in both strains. Five of six SHR had mean coherence (<0.5), while four of seven SDR exhibited coherence (<0.5). Together, these results demonstrate substantial nonstationarity in autoregulatory dynamics in both SHR and SDR. Furthermore, they indicate that the nonstationarity accounts for most of the dynamic complexity in SDR, but that it accounts for only a part of the dynamic complexity in SHR.