bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies of glacial history in Arctic Canada. I. Pumice, radiocarbon dates, and differential postglacial uplift in the eastern Queen Elizabeth Islands
Authors: Blake Jr. Weston
Published: October 2008

Dark brown pumice has been discovered recently on raised beaches of Ellesmere and Devon Islands, and in archeological sites on Baffin Island. It is similar in appearance and chemical composition to pumice associated with raised marine features throughout northern Europe, especially along the coasts of Norway and Spitsbergen. The source area for the pumice is uncertain, but Iceland is a good possibility.Radiocarbon dates on driftwood and whale bones imbedded in beaches at the "pumice level", as well as at higher and lower elevations, indicate that the pumice arrived approximately 5000 years ago.The pumice serves as a time-line and provides a means of correlating widely-separated marine features. Because these features now occur at different elevations, the amount and direction of tilt can be calculated. Also, former ice centers can be delineated, as the areas which have undergone the greatest uplift are those where the ice cover was once thickest. In Arctic Canada the "pumice level" rises westward along Jones Sound—from 16.5 m a.s.l. at the mouth of South Cape Fiord, Ellesmere Island, to 24.0 m at the eastern tip of Colin Archer Peninsula, Devon Island, ca. 130 km away. It also rises northwestward toward the head of South Cape Fiord.The Jones Sound information, plus radiocarbon dates from elsewhere in the Queen Elizabeth Islands indicating the approximate position of the shoreline at the same time, shows that there is a region in the eastern and central part of the archipelago where >25 m of uplift has occurred during the last 5000 years. This region, including considerable areas that are now sea, is believed to have been covered by a major ice sheet during the last glaciation.
Recent coastal submergence of the Maritime Provinces, Canada
Authors: Grant Douglas R.
Published: October 2008

Hydrographic, archeologic, and geologic evidence indicates that for the last 4000 y the Maritime Provinces have been submerging three to five times faster than the 6 cm/century rate of eustatic rise of sea level. After correcting for the eustatic change, the Bay of Fundy shows an anomalous submergence of 24 cm/century, of which at least 15 cm/century is probably due mainly to rise of high tide, or increase of tidal range, beginning 4000–6000 y ago as eustatic sea-level rise widened and deepened the entrance to the Gulf of Maine. Submergence of the Atlantic coast of Nova Scotia, on the other hand, exceeds the eustatic rate by 9 cm/century, which can be largely explained by new mathematical models as isostatic subsidence of the earth's crust as the sea deepened eustatically over the continental shelf. Only a small part of the residual anomalies of 9 cm and 4 cm/century for the Fundy and Atlantic coasts, respectively, can be attributed to a combination of additional subsidence due to geosynclinal downwarping and relaxation of a possible glacier-margin peripheral bulge, thereby implicating other modes of regional crustal lowering.
Paleolimnological evidence for the long-range atmospheric transport of acidic pollutants and heavy metals into the Province of Quebec, eastern Canada
Authors: Ouellet M. , Jones H. G.
Published: October 2008

The present study deals with the geochemical stratigraphic evolution of the recent sediments of 26 lakes located throughout the Province of Quebec, Canada. Although there is no major anthropogenic activity within the watersheds of many of these lakes, it is shown that Pb, Zn, Hg, and Cu levels in the most recent sediments of all lakes increased significantly from 1940 onwards. It is suggested that these increases are due to the increased burning of fossil fuels (particularly coal). The heavy-metal increases tend to be relatively high, especially for Pb, Hg, and Zn, in the sediments of lakes from areas close to the U.S.A.–Quebec boundary, while lakes in more remote areas show smaller increases in the strata laid down in the same time periods. Pb contents in the sediments show a sustained increase in all of the upper strata. However, the subsequent reduction in the stratigraphic concentration of Zn and Hg since 1960 in both an acidified system (Lake Tantare) and a non-acidified lake (Lake Laflamme) might be the result of the important decrease of the total particulate emissions to the atmosphere associated with new technology for coal-fired power plants and the use of cleaner energy sources.The increase in Al in the sediments of Lake Tantare since 1950 is attributed to the processes of surface water acidification of this watershed induced by the long-range atmospheric transport of SOx and NOx.Based on the sedimentary anthropogenic enrichment factor (SAEF) values for the remote sites there is no evidence in the present study for associating the origin of certain heavy metals in these lake sediments with alternative anthropogenic sources such as the Ni and Cu smelting complexes located in Sudbury (Ontario) and Rouyn–Noranda (Quebec). The major sources of heavy-metal deposition and acid precipitation are thus associated with the long-range transport of emissions from fossil fuel combustion originating in the heavily industrialized American Midwest region.
Penokean remagnetization of the basal Huronian Dollyberry Lake basalts near Elliot Lake, Ontario
Authors: Stupavsky M. , Symons D. T. A.
Published: October 2008

The Dollyberry Lake volcanics occur at the base of the Huronian Supergroup and outcrop ~15 km north of Elliot Lake, Ontario. Ten specimens were collected from each of 36 sites in the volcanics and from a further five sites in stratigraphically equivalent volcanics ~9 km east of Elliot Lake. Alternating field (AF) and thermal step demagnetizations were done on two specimens from each site up to 100 mT and 650 °C, respectively. AF demagnetization led to the isolation of an A component in 33 sites, a B component in three sites, and both components in two sites. Fold tests demonstrate that both the A and B components are postfolding in origin at the >97 and >80% confidence level, respectively. It is argued that the A component (pole 154°W, 56°N, δp = 8°, δm = 10°) was acquired during the Penokean Orogeny at ~2215 ± 40 Ma, and that the B component (pole 60°W, 20°S, δp = 8°, δm = 13°) was acquired probably at ~ 1900 ± 100 Ma in response to some geographically restricted thermal or chemical event. The results indicate that the coeval Thessalon volcanics studied by Symons and O'Leary retain the Penokean A component. This leads to the retraction of their conclusion that the superadjacent uranium ores were formed at an ~35° paleolatitude and to the conclusion by analogy that the Penokean Orogeny was the only significant orogenic event in the evolution of the ore deposits.
Recristallisation des calcaires micritiques en fonction de la maturation thermique dans les Basses-Terres du Saint-Laurent du Québec
Authors: Bertrand R. , Humbert L. , Achab A. , Calise G. , Chagnon A. , Héroux Y. , Globensky Y.
Published: October 2008

Typical sections of the Ordovician carbonate platform sequence in the St. Lawrence Lowlands (Beekmantown, Chazy, Black River, Trenton, and Utica Groups) were sampled at Neuville, Joliette, and Montreal, in the Province of Quebec. The purpose of this work was to determine the level of thermal maturation of the carbonates using organic matter and clay studies, and to correlate it with the crystal characteristics of the microcrystalline calcite.The studied formations are supermature in the Joliette and Montreal areas, whereas they are only mature at Neuville.The numerical analysis of the petrographic data shows that some microstructures observed in the rock samples and the size and morphology of the microcrystalline calcite crystals are partly related to the thermal maturation as determined by other methods.
Late glacial molluscs from the Cooking Lake moraine, Alberta, Canada
Authors: Emerson Donald
Published: October 2008

Several species of freshwater mollusc, with radiocarbon dates of 10 900 – 9050 years BP, have been recovered from supraglacial and intraglacial lacustrine sediments in the Cooking Lake moraine region of south-central Alberta, Canada. The organisms indicate the onset of a warming trend in the region that lasted at least 2000 years, marking the final stages of melting in the continental Wisconsin ice sheet.This period of climatic amelioration correlates with a similar trend in southwestern Alberta during the time interval 13 000 – 9000 years BP based also on the evidence of late and early postglacial molluscan communities.
Probable Late Wisconsinan ice margin on the upper continental slope off St. Pierre Bank, eastern Canada
Authors: Bonifay Denis , Piper David J. W.
Published: October 2008

Seismic reflection profiles from the continental slope off St. Pierre Bank show a distinctive acoustic facies characterized by incoherent reflections (unit E) overlain by 5–20 m of stratified sediments (units D–A). Cores from unit E include poorly sorted silty diamict, locally overconsolidated and including in places some foraminifera. Stratified sediments also occur in places in this facies.The overlying sediments of units D–A, except for the topmost metre of unit A, have a foraminiferal fauna dominated by Elphidium excavatum forma clavata and Cassidulina reniforme, which has been interpreted elsewhere as indicating ice-margin sedimentation. The sediments contain turbidites and rare ice-rafted detritus, and are bioturbated. Accelerometer mass spectrometer radiocarbon dating of shells from the stratified sediments yielded dates between 3.3 and 11.8 ka. Facies E, the top of which has an extrapolated age of 11.5–12.0 ka, is interpreted as slumped morainal diamict and proglacial sediment resulting from a late Wisconsinan ice surge through Halibut Channel. Low basal shear stresses in this thin ice surge left little record in the mud-accumulating basins of the continental shelf.
Large bedforms and associated hydraulic conditions within microtidal-inlet channels, southern Gulf of St. Lawrence, Canada
Authors: Matsushita P. N. , McCann S. B.
Published: October 2008

A variety of large bedforms, at two scales (sand waves, dunes), occur within the throat section of-small microtidal-inlet channels. The larger forms, which have an average length of 32 m and height of 1.0 m, remain ebb oriented throughout the tidal month but are only actively modified at large tides. The smaller forms, which may be superimposed on the larger, are partially reworked each tidal cycle but are also predominantly ebb oriented. Tidal-current measurements confirm the dominance of ebb-tidal flow in the inlet throats and indicate that despite the small tidal range (maximum 1.1 m), ebb currents may exceed 1.0 m s−1 with associated shear velocities of 0.14 m s−1.
A woolly mammoth (Proboscidea, Mammuthus primigenius) molar from the Hudson Bay Lowland of Manitoba
Authors: Nielsen Erik , Churcher C. S. , Lammers G. E.
Published: October 2008

The first fossil mammal from the Hudson Bay Lowland of Manitoba, a molar from the woolly or Siberian mammoth, Mammuthus primigenius, is described from near Bird. A lophar index of 9.0 and an enamel thickness of 1.5–2.3 mm allow the tooth to be assigned to an early form of the species. Although in situ provenance of the molar is unknown, it is likely that the molar derives from Early Wisconsinan or Sangamon sediments that outcrop in the area. A boreal steppe or steppe–tundra environment is indicated by the presence of woolly mammoth, supporting a depositional environment north of the then tree line previously established for the Nelson River sediments.
The isotopic composition of strontium of the Early Jurassic North Mountain Basalts, Nova Scotia
Authors: Jones Lois M. , Mossman David J.
Published: October 2008

The initial isotopic composition of strontium of the Early Jurassic North Mountain Basalts was determined for two of three flow units: the lower unit and upper unit. Each unit was sampled along the outcropping basalts over a distance of 170 km. The initial 87Sr/86Sr ratios are remarkably constant for each unit. For the lower unit, the initial ratios range from 0.70591 to 0.70609; for the upper unit, the range is 0.70675–0.70687. The relatively high ratio could represent tapping of a magma source in an isotopically heterogeneous mantle. Alternatively, the magma could have resided for a time in the lower crust and assimilated crustal material, thereby increasing the radiogenic 87Sr content. Mixing had to have been very efficient, as indicated by similar initial ratios over considerable distances. With the extrusion of the upper unit, an isotopically different part of the mantle was tapped, or, more likely, the magma was retained within the lower crust long enough to assimilate additional crustal material and mix sufficiently well to yield the consistently higher initial ratio observed throughout the upper unit.
Lithophile-element systematics of Archean greenstone belt Au–Ag vein deposits: implications for source processes
Authors: Kerrich R. , Fryer B. J.
Published: October 2008

Potassic alteration domains of greenstone belt lode gold deposits are characterized by systematic partitioning between lithophile elements. K, Rb, and Ba are generally co-enriched and linearly correlated over almost three orders of magnitude in abundance, where K/Rb = 220–400 and K/Ba = 30–85; K/Cs (~104) and K/Tl (~2 × 104) are also correlated, though more weakly. Lithium abundances and Rb/Sr ratios are erratic in altered rocks. These interelement trends, collectively, are present in deposits variously hosted by ultramafic, mafic, or felsic volcanic rocks and sediments or granitoids. Magmatic processes involving crystal fractionation of biotite, K-feldspar, and plagioclase generate trends to systematically diminished K/Rb (≥50), K/Li, K/Cs, and K/Tl but enhanced K/Ba (≤8 × 103) and Rb/Sr in most late-stage differentiates. Such "late-stage" trends are the rule in "magmatophile" deposits, including the Archean Cadillac molybdenite deposit, Phanerozoic Cu- and Mo-"porphyry" deposits, Sn–W greisens, and most pegmatites. Accordingly, magmatic processes of this type can be ruled out as the dominant source of volatiles for gold-forming systems. The compliance of K/Rb and K/Ba ratios in potassic alteration domains of Au deposits with values characteristic of main-trend igneous rocks, or "average" crust, implies that K, Rb, and Ba were partitioned into the hydrothermal ore-forming fluids in approximately the same ratios as in the source rocks. Dehydration reactions in the source rocks or equilibration of fluids with source rocks under conditions of low water/rock ratio, rather than magmatic processes, may satisfy the requirement for proportional K, Rb, and Ba co-enrichment.
Étude métallographique des différentes associations minérales et caractérisation chimique des minéraux uranifères du gisement de Cigar Lake (Saskatchewan, Canada)
Authors: Reyx Jean , Ruhlmann François
Published: October 2008

The Cigar Lake deposit, discovered in 1981, represents one of the richest uranium occurrences known in the province of Saskatchewan. The eastern margin of the Athabasca Basin can be considered as one of the richest uraniferous provinces in the Western World.Being located at the unconformity between the Aphebian metasediments and the Helikian sandstone cover, this deposit is classified in the group of deposits spatially related to the Proterozoic unconformity. The study of this deposit, exceptional in its dimensions, grade, and tonnage, was made possible through a series of 170 boreholes drilled to delineate the whole orebody to a depth of 440 m.The metallographic study of the mineralizations in the main orebody, hosted in the basement, and the so-called "perched" mineralization in the cover rocks, led to the definition of three major mineralizing stages, which contributed in varying degrees to ore deposition.A major stage is characterized by the association of U–Ni–Co–As–S ± Mo–Bi–Cu–Zn–Pb and reflects the polyphased nature of this hydrothermal stage. This early deposition of the uraniferous phase (massive, botryoidal, and euhedral uraninite) was followed, on one hand, by a phase precipitating nickel–cobalt and Feron arsenides and sulfoarsenides, and on the other hand, by a phase exclusively of sulphides. The age of emplacement of this stage is 1341 Ma, and it corresponds to the very important metallogenic period in the Athabasca during which the main economic ore occurrences "related to unconformities" were emplaced.The second stage appears only in the metamorphic units of the Aphebian basement. It is represented by an uraninite–sulphide paragenesis, the uraninite being characterized principally by the presence of thorium and, as well, a lead content lower than that in the uranous oxides stage.The third mineralizing stage affects the basement rocks, the main orebody, and the cover rocks with their perched mineralization. It is a simple pitchblende – iron or iron–nickel sulphide and (or) hematite paragenesis with an age of emplacement of 323 Ma. This type of mineralization is identical to that shown in a certain number of occurrences in the Athabasca Plateau and it is considered to be related to the Hercynian orogeny.The first and third of these three mineralizing stages fit perfectly in the metallogenic model for this part of the Canadian Shield. A comparison of these stages with the main mineralizing stages defined in the Carswell Dome structure and with some occurrences in eastern Athabasca was carried out in order to define a model of the metallogenic evolution of northern Saskatchewan. [Journal Translation]
Low-temperature thermal history of the Gilmore Dome area, Fairbanks Mining District, Alaska
Authors: Murphy John M. , Bakke Arne
Published: October 2008

Eight apatite and two zircon fission-track ages provide evidence of complex Tertiary thermal overprinting by hydrothermal fluids in the Gilmore Dome area. Five ages on apatite from the Fort Knox gold deposit average 41 Ma, one from the Stepovich prospect is 80 Ma, and two from Pedro Dome average 67 Ma. Elevations of these samples overlap but their ages do not, indicating that each area experienced a different thermal history.Ages of apatite from the Fort Knox gold deposit decrease with elevation from 42 to 36 Ma but have data trends indicative of complex cooling. Two ~51 Ma ages on zircon indicate that maximum temperatures approached or exceeded ~180 °C. An alteration assemblage of chalcedony + zeolite + calcite + clay in the deposit resulted from deposition by a paleo-hydrothermal system. The data suggest that the system followed a complex cooling path from > 180 to < 110 °C between 51 and 36 Ma, and that final cooling to below 60 °C occurred after ~25 Ma.The 80 Ma age from Stepovich prospect either resulted from cooling after intrusion of the underlying pluton (~90 Ma) or records postintrusion thermal overprinting sometime after ~50 Ma. The 67 Ma samples from Pedro Dome may also have experienced partial age reduction during later heating. The differences in the data from the different areas and the presence of a late alteration assemblage at Fort Knox suggest that the fluids responsible for heating were largely confined to the highly fractured and porous Fort Knox pluton.
Multimethod radiometric age for a bentonite near the top of the Baculites reesidei Zone of southwestern Saskatchewan (Campanian–Maastrichtian stage boundary?)
Authors: Baadsgaard H. , Lerbekmo J. F. , Wijbrans J. R. , Swisher III C. C. , Fanning M.
Published: October 2008

A 15 cm thick bentonite at the top of the Baculites reesidei Zone in Cruikshank Coulee north of Herbert in southwestern Saskatchewan yielded biotite, sanidine, plagioclase, and zircon. Rb–Sr analyses give a mineral isochron with an age of 72.5 ± 0.2 Ma (± 2σ). U–Pb analyses of zircon produced concordant 206Pb/238U and 207Pb/235U ages of 72.4 ± 0.4 Ma (± 2σ) and 72.6 ± 0.4 Ma (± 2σ), respectively. Laser 40Ar/39Ar dating of sanidine and biotite revealed ages of 72.5 ± 0.2 Ma (± SE) and 72.6 ± 0.2 Ma (± SE), respectively. If the Campanian–Maastrichtian stage boundary is near the top of the Baculites reesidei Zone, then the overall average age of 72.5 ± 0.4 Ma dates the stage boundary.
Seismic velocity structure of the Queen Charlotte Basin beneath Hecate Strait
Authors: Spence G. D. , Asudeh I.
Published: October 2008

Seismic refraction data across Hecate Strait in the northern Queen Charlotte Basin were collected in a coincident reflection and refraction survey. Crustal velocity models provide a framework to help understand the formation of the sedimentary basin and the processes occurring near the Queen Charlotte Fault, a major ocean–continent transform fault. Beneath the sediments, which have a maximum thickness of 6 km, a velocity gradient extends from about 5 to 8 km depth, within which velocities increase typically from 6.3 to 6.4 km∙s−1. A thick constant-velocity region was found down to a depth varying from 14 to 22 km, with the smallest depths located beneath the central basin. The base of the constant-velocity layer was marked by a distinct mid-crustal interface, across which velocities increased from 6.4–6.5 km∙s−1 to approximately 6.8–6.9 km∙s−1. Moho was interpreted to be at a near-uniform depth of 26–28 km beneath Hecate Strait and the eastern Queen Charlotte Islands. The associated variation in crustal thickness beneath the basin implies crustal thinning, perhaps caused by extension, of 30% or more.The mid-crustal interface may mark the change to a more mafic and perhaps ductile lower crust. The interface appears to be about 1–4 km deeper than the brittle–ductile transition, as indicated by the estimated depth to the 450 °C isotherm and by the moderate increase in reflectivity on the seismic reflection sections. Ductile flow may also occur in the lower crust near the Queen Charlotte Fault, where the relative motion of the oceanic plate induces lithospheric flow and thinning beneath both the ocean and the continent. The observed decrease in Moho depth from 28 to 21 km near the fault is consistent with recent (1989) numerical predictions of I. Reid for lithospheric flow near ocean–continent transforms.
Holocene sea-level change on the central west coast of Vancouver Island, British Columbia
Authors: Friele Pierre A. , Hutchinson Ian
Published: October 2008

A new Holocene relative-sea-level (RSL) curve is proposed for the central west coast of Vancouver Island based on topographic surveys of coastal landforms and the stratigraphy of coastal deposits. Six study sites are described on Vargas Island and Esowista and Ucluth peninsulas and 23 previously unpublished radiocarbon ages that constrain mean-sea-level (MSL) position are presented. A long-term rise in RSL from an early Holocene (> 7000 BP) lowstand below −3 m asl is documented from dates on tree stumps in the intertidal zone and salt-marsh peats and forest-floor deposits buried by marine sands and gravels. Submergence culminated in a stillstand from 6000 to 4800 BP, marked by the development of a strandline at 6 m asl (MSL ≈ 3.2 m asl). A fall in RSL is documented by a strandline at 4.0–4.5 m asl, which dates from 2700 to 2000 BP (MSL ≈ 2.0 m asl). Little is known of the dynamics of emergence between 4800 and 2700 BP or from 2000 BP to the present, although the absence of strandlines below 4 m asl suggests continuous emergence during the last two millenia. This submergence–emergence cycle is unique in southern British Columbia. A simple simulation model suggests that late Holocene emergence was induced by tectonic uplift of the edge of the America plate margin.
Pleistocene stratigraphy, paleopedology, and paleoecology of a multiple till sequence exposed on the Little Bear River, Western District of Mackenzie, N.W.T., Canada
Authors: Hughes O. L. , Tarnocai C. , Schweger C. E.
Published: October 2008

The Little Bear River section lies in a transition zone between Mackenzie Lowland and Canyon Ranges of Mackenzie Mountains. Within the transition zone, the maximum extent of the Laurentide ice sheet overlaps the former extent of montane glaciers that emanated from the higher parts of Canyon Ranges or from the still higher Backbone Ranges to the southwest. Five montane tills, each with a paleosol developed in its upper part, indicate five separate glaciations during each of which a valley glacier emanating from the headwaters of Little Bear River extended eastward into the transition zone. The uppermost of the montane tills is overlain by boulder gravel containing rocks of Canadian Shield origin deposited by the Laurentide ice sheet.Solum and B horizon depths, red colours, and lack of leaching and cryoturbation indicate that although each successive interglacial interval was cooler than the preceding one, even the last of the intervals was warmer than the Holocene. Climatic conditions during one of the intervals inferred from the paleobotanic data, particularly spruce forest development, are consistent with conditions inferred from the associated paleosol.The uppermost of the montane tills is thought to correlate with till of Reid (Illinoian) age in central Yukon. The paleosol developed on that till is, accordingly, thought to correlate with the Diversion Creek paleosol developed on drift of Reid age. The Laurentide boulder gravel is assigned to a stade of Hungry Creek Glaciation of Late Wisconsinan age. The Laurentide ice sheet reached its apparent all-time western limit during the Hungry Creek Glaciation maximum.
The Behavior of Long Piles Under Compressive Loads in Sand
Authors: Hanna T. H. , Tan R. H. S.
Published: October 2008

Laboratory load tests were conducted on piles 15.9–38.1 mm in diameter and up to 1.8 m long in a compact dry sand. The piles were buried in the sand stratum during sand placement. Two conditions of test were imposed—in one the pile was free to settle as the sand was placed around it and in the other the top end of the pile was rigidly clamped thus preventing any movement of the pile during sand placement. The piles were provided with sensitive axial load transducers at their base and at seven positions along their length.During test preparation a residual force system was locked in the pile and it was found that this initial residual state controlled the subsequent load and movement behavior of the pile. Data are given which show the mechanics of load mobilization and sharing for piles of different length–diameter ratios between 10 and 112, different axial flexibilities, and different diameters. In addition one series of tests examined the significance of footings located at regular intervals along the pile shaft. It is shown very clearly that extensive arching occurs along the lower lengths of the piles thus confirming earlier work of Vesić. The multiunderreamed pile is much more efficient than a straight sided pile of equal diameter. The mechanism of load development in a pile is not in agreement with any of the standard pile bearing capacity theories but agrees with concepts presented earlier by the authors. The significance of the experimental findings is discussed.
Instrumented Impact Cone Penetrometer
Authors: Dayal Umesh , Allen John H.
Published: October 2008

The present paper describes the development of an instrumented impact cone penetrometer for a direct measurement of in situ strength properties of a soil target. The developed penetrometer, in addition to providing acceleration signatures (as obtained by previous investigators), is capable of recording cone thrust and local side friction simultaneously and continuously. The procedures have been outlined for estimating in situ strength properties and soil type of the target materials throughout the penetrated depth from the output records of these sensors. Typical test results generated from an on-going experimental program aimed at providing the data for (1) understanding the penetration mechanism, (2) development of penetration theory, and (3) designing the penetrometer for field tests, i.e. in situ testing of ocean floor soils, are also presented.
Field Investigation of Permeability Ratio of New Liskeard Varved Soil
Authors: Kenney T. Cameron , Chan H. T.
Published: October 2008

The results are reported of an investigation to determine the in situ permeability ratio of a large body of varved soil near New Liskeard, Ontario. Permeability ratio is defined as the ratio of coefficients of permeability for flow parallel to and perpendicular to the varves. The method used was to measure with piezometers the pattern of water pressures within a natural slope and to determine by trial and error calculations the value of permeability ratio which would yield a similar pattern of water pressures. The value of this permeability ratio was found to be rK < 5.The in situ magnitudes of hydraulic gradient were appreciably smaller than unity and this brought into question the usual assumption that the flow obeyed Darcy's law. Comparisons between calculated patterns of water pressure based on Darcy flow and non-Darcy flow and measured patterns of water pressure indicated that the best fit was obtained based on the assumption of Darcy flow.It is hypothesized that soils consisting of distal varves have small values of permeability ratio and that soils consisting of proximal varves can have large values of permeability ratio.
An Apparatus for Plane Strain and True Triaxial Testing of Undisturbed Soil Samples
Authors: Mitchell R. J.
Published: October 2008

Extension of continuum analytical techniques to the solution of soil mechanics boundary value problems has created a need for more detailed information on the strength and stress–strain relations of soils. This note describes an apparatus that was developed to provide information on the plane strain and true triaxial behavior of undisturbed samples of soil.
A Slope Failure in Swelling Clay
Authors: Kassiff G. , Alpan I.
Published: October 2008

A recent heavy rainy season in the semiarid climatic conditions of northern and central Israel caused a number of slope failures of embankments and bridge abutments in expansive clay soils.Failure of a 9 m high slope of a bridge abutment is reported. The failure occurred owing to migration of moisture into the clay a short time after the slope was completed. Soil characteristics such as plasticity, swelling potential, and shear strength are presented and discussed. The stability of the slope was analyzed using Taylor's chart and strength parameters obtained from laboratory tests. It is concluded that failure occurred owing to substantial loss of strength following swelling of the clay. Results of laboratory tests for shear strength after saturation and swelling seem to correlate well with actual field conditions in this case.
Critical Period for Stability of an Excavated Slope in Clay Soil
Authors: Kenney T. Cameron , Uddin Saif
Published: October 2008

Bishop and Bjerrum have hypothesized that the critical period for stability of a slope excavated in weak clay soil would not occur at the end of the excavation period but, rather, would occur some time after completion of the excavation when the pore-water pressures in the slope corresponded to natural seepage conditions; for natural seepage conditions the pore-water pressures would no longer be influenced by the effects of stress changes in the soil caused by excavation of the slope. Evidence in support of this hypothesis will be presented in the form of a stability study of an excavated slope along the Kimola Canal in Finland. It will be shown from the results of stability calculations, based on measured pore-water pressures, that the safety factor of the slope decreased immediately after excavation was completed and that the slope failed some time later when the water-pressure conditions were most adverse to stability.
The Failure Criteria for Soils
Authors: Nagaraj T. S. , Somashekar B. V.
Published: October 2008

Analysis of experimental results using extended Tresca and extended Von Mises criteria show substantial difference between experimental and predicted values particularly when the intermediate principal stress approaches the major principal stress. Modified forms of these criteria have been suggested and examined for their validity.
Estimating settlements in dry sands during earthquakes
Authors: Finn W. D. L. , Byrne P. M.
Published: October 2008

An analytical method for predicting the settlement of a horizontal stratum of dry sand subjected to earthquake excitation is presented. An equivalent linear viscoelastic dynamic analysis is used to determine the time-history of shear strains at various levels within the stratum. The vertical strains caused by these shear strains are calculated by an empirical relationship shown to be in close agreement with laboratory test data over a wide range of relative densities. This allows the settlement distribution with depth to be calculated as a function of time.The method was applied to a 50 ft (15 m) stratum of sand. A base acceleration corresponding to 0–10 s of the N–S component of El Centro earthquake was used. Settlement distribution vs. depth, as well as surface settlements for various relative densities and earthquake scaling factors are shown. The effect of surcharge loading on settlements is investigated in an approximate manner.The results may be used to estimate differential settlement of a structure due to an earthquake. The results show that while the compaction of the upper layers may be sufficient to reduce the settlements due to static loads to tolerable amounts, deep-seated settlements will still occur during an earthquake.
Reanalysis of simple shear soil testing
Authors: Prevost Jean-Herve , Høeg Kaare
Published: October 2008

Simple shear devices are used fairly extensively in soil mechanics research, lately especially in connection with cyclic testing. This presentation starts out by extending existing isotropic, elastic analyses of stresses and strains in the simple shear test. The effects of partial differential boundary slippage at the interface between the soil specimen and the top and bottom caps of the apparatus are analyzed. A comparison is made between constant volume and truly undrained simple shear tests.Because there is a coupling of shear and normal strains in soils, both may result from either shear or normal stresses, and vice versa. Therefore, an applied simple shear state of strain will not in general produce a simple shear state of stress in a soil sample, and it is shown analytically and experimentally that significant changes in lateral stresses do occur in simple shear tests. Such patterns of behavior are thereafter incorporated in the interpretation of cyclic loading simple shear tests on sand.
Item Response Theory and Clinical Measurement
Authors: Reise Steven P. , Waller Niels G.
Published: October 2008

In this review, we examine studies that use item response theory (IRT) to explore the psychometric properties of clinical measures. Next, we consider how IRT has been used in clinical research for: scale linking, computerized adaptive testing, and differential item functioning analysis. Finally, we consider the scale properties of IRT trait scores. We conclude that there are notable differences between cognitive and clinical measures that have relevance for IRT modeling. Future research should be directed toward a better understanding of the metric of the latent trait and the psychological processes that lead to individual differences in item response behaviors.
Pandora's Box Contained Bait: The Global Problem of Introduced Earthworms
Authors: Hendrix Paul F. , Callaham Mac A. , Drake John M. , Huang Ching-Yu , James Sam W. , Snyder Bruce A. , Zhang Weixin
Published: October 2008

Introduced exotic earthworms now occur in every biogeographic region in all but the driest or coldest habitat types on Earth. The global distribution of a few species (e.g., Pontoscolex corethrurus) was noted by early naturalists, but now approximately 120 such peregrine species are recognized to be widespread from regional to global scales, mainly via human activities. Species adapted to human transport and to colonization of disturbed habitats are most widespread and are the principal invasive species. We identify a number of endogenous and exogenous factors that may contribute to the successful establishment and spread of peregrine species. Quantification of these factors may help to determine why certain species become invasive while others do not. Recent advances in theory and modeling of biological invasions and in molecular techniques should prove fruitful in improving our understanding of invasive earthworms, as well as in predicting their impacts on ecosystems.
Chemical Synthesis of Novel Plasmonic Nanoparticles
Authors: Lu Xianmao , Rycenga Matthew , Skrabalak Sara E. , Wiley Benjamin , Xia Younan
Published: October 2008

Under the irradiation of light, the free electrons in a plasmonic nanoparticle are driven by the alternating electric field to collectively oscillate at a resonant frequency in a phenomenon known as surface plasmon resonance. Both calculations and measurements have shown that the frequency and amplitude of the resonance are sensitive to particle shape, which determines how the free electrons are polarized and distributed on the surface. As a result, controlling the shape of a plasmonic nanoparticle represents the most powerful means of tailoring and fine-tuning its optical resonance properties. In a solution-phase synthesis, the shape displayed by a nanoparticle is determined by the crystalline structure of the initial seed produced and the interaction of different seed facets with capping agents. Using polyol synthesis as a typical example, we illustrate how oxidative etching and kinetic control can be employed to manipulate the shapes and optical responses of plasmonic nanoparticles made of either Ag or Pd. We conclude by highlighting a few fundamental studies and applications enabled by plasmonic nanoparticles having well-defined and controllable shapes.
A Crisis in the Marketplace: How Food Marketing Contributes to Childhood Obesity and What Can Be Done
Authors: Harris Jennifer L. , Pomeranz Jennifer L. , Lobstein Tim , Brownell Kelly D.
Published: October 2008

Reducing food marketing to children has been proposed as one means for addressing the global crisis of childhood obesity, but significant social, legal, financial, and public perception barriers stand in the way. The scientific literature documents that food marketing to children is (a) massive; (b) expanding in number of venues (product placements, video games, the Internet, cell phones, etc.); (c) composed almost entirely of messages for nutrient-poor, calorie-dense foods; (d) having harmful effects; and (e) increasingly global and hence difficult to regulate by individual countries. The food industry, governmental bodies, and advocacy groups have proposed a variety of plans for altering the marketing landscape. This article reviews existing knowledge of the impact of marketing and addresses the value of various legal, legislative, regulatory, and industry-based approaches to change.

*This PDF was amended on Aug. 5, 2009: See explanation at http://arjournals.annualreviews.org/doi/abs/10.1146/annurev.pu.30.090805.200009
A short duration of high-fat diet induces insulin resistance and predisposes to adverse left ventricular remodeling after pressure overload
Authors: Raher Michael J. , Thibault Helene B. , Buys Emmanuel S. , Kuruppu Darshini , Shimizu Nobuyuki , Brownell Anna-Liisa , Blake Sarah L. , Rieusset Jennifer , Kaneki Masao , Derumeaux Genevieve , Picard Michael H. , Bloch Kenneth D. , Scherrer-Crosbie Marielle
Published: October 2008

Insulin resistance is an increasingly prevalent condition in humans that frequently clusters with disorders characterized by left ventricular (LV) pressure overload, such as systemic hypertension. To investigate the impact of insulin resistance on LV remodeling and functional response to pressure overload, C57BL6 male mice were fed a high-fat (HFD) or a standard diet (SD) for 9 days and then underwent transverse aortic constriction (TAC). LV size and function were assessed in SD- and HFD-fed mice using serial echocardiography before and 7, 21, and 28 days after TAC. Serial echocardiography was also performed on nonoperated SD- and HFD-fed mice over a period of 6 wk. LV perfusion was assessed before and 7 and 28 days after TAC. Nine days of HFD induced systemic and myocardial insulin resistance (assessed by myocardial 18F-fluorodeoxyglucose uptake), and myocardial perfusion response to acetylcholine was impaired. High-fat feeding for 28 days did not change LV size and function in nonbanded mice; however, TAC induced greater hypertrophy, more marked LV systolic and diastolic dysfunction, and decreased survival in HFD-fed compared with SD-fed mice. Compared with SD-fed mice, myocardial perfusion reserve was decreased 7 days after TAC, and capillary density was decreased 28 days after TAC in HFD-fed mice. A short duration of HFD induces insulin resistance in mice. These metabolic changes are accompanied by increased LV remodeling and dysfunction after TAC, highlighting the impact of insulin resistance in the development of pressure-overload-induced heart failure.
Quantitative Analysis of Vascular Endothelial Growth Factor in Liver Metastases from Pancreatic Carcinoma as a Predictor of Chemotherapeutic Effect and Prognosis
Authors: Tawada Katsunobu , Ishihara Takeshi , Kobayashi Akitoshi , Yamaguchi Taketo , Tsuyuguchi Toshio , Matsuyama Masato , Yokosuka Osamu
Published: October 2008

Purpose: In pancreatic carcinoma, vascular endothelial growth factor (VEGF) expression at the primary site has been suggested to be a prognostic parameter. We quantitatively analyzed VEGF expression in liver metastases from pancreatic carcinoma and examined the correlation among VEGF expression in liver metastases, clinicopathologic factors, and clinical outcome.

Experimental Design: The subjects consisted of 23 patients with pancreatic adenocarcinoma who had liver metastases and were treated with S-1 and gemcitabine as the first-line treatment. VEGF expression was quantitated by enzyme immunoassay in biopsy specimens of liver metastases and nontumorous liver tissue, and in plasma. In 10 of the 23 patients, VEGF expression was also quantitated in biopsy specimens of the primary pancreatic tumor. All samples were collected before treatment.

Results: The VEGF level in nontumorous liver tissue was 36.6 ± 10.0 pg/mg protein versus 376.8 ± 106.1 pg/mg protein in liver metastases (P = 0.0016). Pretreatment VEGF levels in plasma and in primary pancreatic carcinoma did not correlate with VEGF levels in the corresponding liver metastases. The median VEGF level in liver metastases (138.9 pg/mg protein) was used as the cutoff value between high and low VEGF expression in liver metastases. Patients showing high VEGF expression had a significantly longer progression-free survival and overall survival than patients showing low VEGF expression in liver metastases (P = 0.0219 and P = 0.0074, respectively).

Conclusions: Evaluation of VEGF levels in liver metastases might be useful in assessing the prognosis of patients with metastatic pancreatic carcinoma who are under systemic chemotherapy.
Quantitative live imaging of cancer and normal cells treated with Kinesin-5 inhibitors indicates significant differences in phenotypic responses and cell fate
Authors: Orth James D. , Tang Yangzhong , Shi Jade , Loy Clement T. , Amendt Christiane , Wilm Claudia , Zenke Frank T. , Mitchison Timothy J.
Published: October 2008

Kinesin-5 inhibitors (K5I) are promising antimitotic cancer drug candidates. They cause prolonged mitotic arrest and death of cancer cells, but their full range of phenotypic effects in different cell types has been unclear. Using time-lapse microscopy of cancer and normal cell lines, we find that a novel K5I causes several different cancer and noncancer cell types to undergo prolonged arrest in monopolar mitosis. Subsequent events, however, differed greatly between cell types. Normal diploid cells mostly slipped from mitosis and arrested in tetraploid G1, with little cell death. Several cancer cell lines died either during mitotic arrest or following slippage. Contrary to prevailing views, mitotic slippage was not required for death, and the duration of mitotic arrest correlated poorly with the probability of death in most cell lines. We also assayed drug reversibility and long-term responses after transient drug exposure in MCF7 breast cancer cells. Although many cells divided after drug washout during mitosis, this treatment resulted in lower survival compared with washout after spontaneous slippage likely due to chromosome segregation errors in the cells that divided. Our analysis shows that K5Is cause cancer-selective cell killing, provides important kinetic information for understanding clinical responses, and elucidates mechanisms of drug sensitivity versus resistance at the level of phenotype. [Mol Cancer Ther 2008;7(11):3480–9]
17-Allylamino-17-Demethoxygeldanamycin Down-Regulates Hyaluronic Acid–Induced Glioma Invasion by Blocking Matrix Metalloproteinase-9 Secretion
Authors: Kim Mi-Suk , Kwak Hee-Jin , Lee Ji-Woo , Kim Hea-Jin , Park Myung-Jin , Park Jong-Bae , Choi Kyung-Ho , Yoo Heon , Shin Sang-Hoon , Shin Woon-Seob , Song Eun-Sook , Lee Seung-Hoon
Published: October 2008

Hyaluronic acid (HA) has been implicated in cell adhesion, motility, and tumor progression in gliomas. We previously reported that HA stimulates secretion of matrix metalloproteinase-9 (MMP-9) and induces glioma invasion. However, the molecular mechanism of HA action and therapeutic strategies for blocking HA-induced MMP-9 secretion remain unknown. Here, we report that the Hsp90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG) blocks MMP-9 secretion and that HA-induced nuclear factor-κB (NF-κB) activation is mediated by IκB kinase, which phosphorylates the NF-κB inhibitor IκBα and promotes its degradation. In addition, using an RNA interference approach, we show that the focal adhesion kinase plays a critical role in mediating HA-induced NF-κB activation, which resulted in increased MMP-9 expression and secretion, cell migration, and invasion. Importantly, we show that 17-AAG acts by blocking focal adhesion kinase activation, thereby inhibiting IκB kinase–dependent IκBα phosphorylation/degradation, NF-κB activation, and MMP-9 expression. This leads to suppression of HA-induced cell migration and invasion. Based on our data, we propose that 17-AAG is a candidate drug for treatment of highly invasive gliomas resulting from HA-induced, NF-κB–mediated MMP-9 secretion. (Mol Cancer Res 2008;6(11):1657–65)
Amiodarone Inhibits Arterial Thrombus Formation and Tissue Factor Translation
Authors: Breitenstein A. , Stämpfli S.F. , Camici G.G. , Akhmedov A. , Ha H.R. , Follath F. , Bogdanova A. , Lüscher T.F. , Tanner F.C.
Published: October 2008

Background—In patients with coronary artery disease and reduced ejection fraction, amiodarone reduces mortality by decreasing sudden death. Because the latter may be triggered by coronary artery thrombosis as much as ventricular arrhythmias, amiodarone might interfere with tissue factor (TF) expression and thrombus formation.

Methods and Results—Clinically relevant plasma concentrations of amiodarone reduced TF activity and impaired carotid artery thrombus formation in a mouse photochemical injury model in vivo. PTT, aPTT, and tail bleeding time were not affected; platelet number was slightly decreased. In human endothelial and vascular smooth muscle cells, amiodarone inhibited tumor necrosis factor (TNF)-α and thrombin-induced TF expression as well as surface activity. Amiodarone lacking iodine and the main metabolite of amiodarone, N-monodesethylamiodarone, inhibited TF expression. Amiodarone did not affect mitogen-activated protein kinase activation, TF mRNA expression, and TF protein degradation. Metabolic labeling confirmed that amiodarone inhibited TF protein translation.

Conclusions—Amiodarone impairs thrombus formation in vivo; in line with this, it inhibits TF protein expression and surface activity in human vascular cells. These pleiotropic actions occur within the range of amiodarone concentrations measured in patients, and thus may account at least in part for its beneficial effects in patients with coronary artery disease.