bluuebunny/crossref_metadata_2025 huggingface dataset:
Earthquakes near Rocky Mountain House, Alberta, and their relationship to gas production facilities
Authors: Wetmiller Robert J.
Published: July 2009

A 1980 field survey of earthquake activity near Rocky Mountain House, Alberta, using one digital and six conventional seismographs, recorded 146 microearthquakes (M ≤ 3.4) in 23 days and located 67 of them. The located events, and probably the unlocated events as well, all occurred in a small zone approximately 4 km north–south by 4 km east–west by 1 km thick, centred near 52°12.5′N, 115°15′W at a depth of 4.0 km, with an uncertainty of ±2 km on each of the location coordinates. The activity occurred below and (or) in the Strachan D-3A sour gas reservoir, which is a Devonian-aged limestone reef complex in a section of nearly flat-lying, unfaulted sediments. The earthquakes had a composite thrust-faulting mechanism with generally north-trending, intermediate-dipping planes in the presence of a regional deviatoric stress field that was horizontally compressive and oriented approximately east–west. The earthquake activity may be related to the extraction of the natural gas and related fluids from the reservoir, but the exact relationship cannot be documented at this time.The earthquake activity in the region increased dramatically after the production of gas from the reservoir began in the early 1970's. The tight cluster of activity found by the field survey suggests that all the activity in the region occurred in the same small zone but that earlier events may have been mislocated. Earthquake activity in western Alberta generally is not induced and occurs within a regional seismicity belt spatially continuous with the Intermountain Seismic Belt of the northern United States, but the earthquake activity in Canada seems to be tectonically distinct from that in the U.S.A., being characterized by thrust faulting and horizontally compressive stress.
The tectonic significance of some basic dyke swarms in the Canadian Superior Province with special reference to the geochemistry and paleomagnetism of the Mistassini swarm, Quebec, Canada
Authors: Fahrig W. F. , Christie K. W. , Chown E. H. , Janes D. , Machado N.
Published: July 2009

The Mistassini dykes extend northwest from the Mistassini embayment and comprise both tholeiitic and komatiitic suites. They are probably > 2000 Ma old and yield two major paleomagnetic components. One of these, with a pole at 131°W, 13°S, is thought to be an overprint related to the Elsonian Disturbance 1400–1500 Ma ago. A very steeply down (and reversed) component may be primary and has a pole at 080°W, 50°N.These spacial, chemical, and age relationships between the Mistassini, Molson, Marathon, and Payne River dyke swarms and the Aphebian supracrustal fold belts on the perimeter of the Superior Province suggest a genetic relationship between the dyke swarms and the fold belts. The supracrustal belts are evidence of the opening and closing of oceans, and the dyke swarms are evidence of early-stage failed arms related to these openings. More rarely (for example, the Payne River dykes), early-stage dyke swarms are developed and preserved parallel to the edges of newly developed spreading plate boundaries. Presumably if a spreading episode stops, the dykes themselves may remain as the only evidence of that event. Probably all the world's great continental dyke swarms have the above-described tectonic setting, and the number and extent of dyke swarms during a geological epoch may be a measure of the number and vigour of spreading events.
On deglaciation-induced perturbations of the geoid
Authors: Wolf Detlef
Published: July 2009

The importance of geoid perturbations in interpreting tilts of glacial lake levels is investigated, using a representative theoretical model. It is shown that near the ice margin, the slope of the Earth's perturbed surface is everywhere large compared with the slope of the associated undulation of the geoid. Perturbations of the geoid may therefore be neglected in interpretations of glacial strandline tilt.
The silver deposits at Cobalt and Gowganda, Ontario. II: An experiment in age determinations employing radiometric and paleomagnetic measurements
Authors: Andrews A. J. , Masliwec A. , Morris W. A. , Owsiacki L. , York D.
Published: July 2009

U–Pb analyses of primary baddeleyite and vein-related secondary rutile, separated from a Nipissing diabase sill at the Castle mine, Gowganda, yield ages of 2217.5 ± 1.6 and 2217.0 + 6 Ma, respectively. The data allow for the possibility that (i) the vein formed at essentially the same time as diabase intrusion, defined within the limits of the intercept age [Formula: see text], or (ii) the vein could have formed up to 8.1 Ma later than intrusion. Paleomagnetic analyses of the diabase suggest that it is part of the older (N2) phase of this widespread intrusive event. Paleomagnetic analyses of a pre-vein granite dike, intrusive into the diabase, provide a minimum time interval of 20 000 – 50 000 years separating intrusion and vein formation.40Ar–39Ar analyses of silicates obtained from ore veins in the Cobalt camp yield highly disturbed age spectra. Paleomagnetic analyses of altered wall rocks to ore veins in both the Castle mine and the Cobalt camp provide a wide range of apparent ages, inconsistent with the U–Pb data. The 40Ar–39Ar and paleomagnetic data are interpreted as indicating a prolonged history of post-vein disturbances during regional tectonism.
Co–Ni arsenide deposits, with accessory gold, in ultramafic rocks from Morocco
Authors: Leblanc Marc
Published: July 2009

A type of Co–Ni arsenide deposit with accessory gold and no silver can be recognized in ultramafic massifs of upper mantle origin. The Bou Azzer deposits (50 000 t Co) are distributed along the borders of serpentinite massifs in an Upper Proterozoic ophiolite (Anti-Atlas, Morocco). They consist of quartz–carbonate lenses with Co (Ni–Fe) arsenides. Gold is related to the skutterudite (8–15 ppm average content). In the Alpine lherzolite massif of Beni Bousera (Rif, Morocco) are found small chromite–Ni arsenides veins (300 t Ni) with accessory gold. They are associated with late orthopyroxene–vermiculite dikes. Several occurrences of As, arsenides, and gold-bearing carbonate rocks are found in serpentinites from various ophiolites. It is proposed that gold was leached by As- and Co2-rich hydrothermal solutions related to the serpentinization of mantle peridotites.
Vein, manto, and chimney mineralization at the Fresnillo sliver–lead–zinc mine, Mexico
Authors: Macdonald A. James , Kreczmer Marek J. , Kesler Stephen E.
Published: July 2009

Discovered in 1553, the Fresnillo mine in central Mexico has produced approximately 18 t Au, 8830 t Ag, 690 000 t Pb, 925 600 t Zn, and 74 000 t Cu (data for production from 1921 to 1984 inclusive). Ore has been mined from an oxide capping near surface and from unoxidized veins, mantos, and chimneys to a depth of 1 km along a strike length of 4 km. Ore zones at depth, in the northwest portion of the mine, are spatially related to a quartz monzonite porphyry stock, which intrudes a sequence of Mesozoic marine sediments that is overlain by terrestrial rhyolites. Manto and chimney mineralization followed development of skarn around the intrusion and was cut, in turn, by the veins that contain the bulk of the ore. The veins cut the quartz monzonite stock. Manto and chimney mineralization is characterized by partial replacement of the Mesozoic sedimentary rocks with axinite, hedenbergite, quartz, carbonate, sulphides, sulphosalts, sulpharsenides, and sulphantimonides. Brecciation preceded replacement in the chimney bodies. One of the largest replacement orebodies, the Cueva Santa Branch Manto in the central part of the mine, contains an orthogonal fracture set formed during antiformal folding. Trends in grade distribution throughout the manto follow the orthogonal fractures, which are filled by quartz and sulphides. Silver/base-metal ratios show marked peaks where manto mineralization abuts against major veins. Fluid-inclusion filling temperatures and salinities are high in ore zones adjacent to the quartz monzonite stock at a depth of 1 km: mean filling temperature is approximately 320 °C (range 230–370 °C), salinity ranges from 4 to 12 eq. wt.% NaCl. Fluid inclusions from ore near surface exhibit lower filling temperatures (a mean of 235 °C and a range of 210–290 °C) and lower salinity (< 1 eq. wt.% NaCl). The data are consistent with a reduction in temperature and with dilution as the hydrothermal fluids flowed away from the intrusive porphyry.δ34S values for sphalerite, galena, and chalcopyrite from deeper and intermediate levels in the mine range from −6.1 to −3.5‰. Calculated δ34SΣS is approximately 0‰, suggesting a magmatic sulphur source. Lead isotopic ratios obtained from galena-bearing vein, manto, and chimney samples throughout the mine fall on a line defined by 34 deposits in northern Mexico with slope of 0.092 ± 0.017 in the 208Pb/204Pb versus 207Pb/204Pb system. The lead data indicate that felsic igneous processes extracted the metal from a Precambrian basement source; this was followed by concentration within mineralized zones during hydrothermal activity.
Exploration implications of production and location data for Ag-rich vein deposits, Trout Lake mining camp, southeastern B.C.
Authors: Goldsmith L. B. , Sinclair A. J. , Read P. B.
Published: July 2009

Ore tonnage production data from 43 former producers in the Trout Lake mining camp are examined using plots of spatial density of deposits and statistical methods. Outlines of mineral belts are established from spatial density with the 0.5 deposit per 4 km2 contour. Probability plots of ore tonnages distinguish two lognormal populations of deposits. Probablity plots of metal grades show four lognormal populations of silver and two of gold. A metal content versus ore tonnage graph draws attention to the similarity in proportions of metals produced from high-tonnage and from medium- + low-tonnage deposits. Triangular graphs of metal contents emphasize the direct relationship between silver and lead; metal ratios suggest some relationships that may be dependent upon host rocks. Linear correlation coefficients of tonnage and metal content show an inverse relationship between tonnage and precious metals and a direct relationship between silver and lead. Multiple regression models established between production tonnages and average grades can estimate deposit size within one order of magnitude.Systematic evaluation of quantitative production and location data can augment exploration decisions.
Regional variation in paleomagnetic polarity of the Matachewan dyke swarm related to the Kapuskasing Structural Zone, Ontario
Authors: Bates M. P. , Halls H. C.
Published: July 2009

The 2.45 Ga Matachewan dykes from the Abitibi Subprovince of the Canadian Shield yield a mean paleomagnetic pole of 42°N, 58°E (α95 = 3°; N (sites) = 36), which is a composite of new and previously published data. Domains of paleomagnetic polarity are defined: an area of dykes predominantly of reversed magnetization in the Abitibi Subprovince contrasts with an area of exclusively normal dykes to the north. The polarity domains are separated by faults related to the 1.95 Ga uplift and exposure of the lower crust in the Kapuskasing Structural Zone and therefore reflect Hudsonian age tectonics in the Archean Superior Province.
Mechanics of formation of the gold-bearing quartz–fuchsite vein at the Dome mine, Timmins area, Ontario
Authors: Moritz Robert P. , Crocket James H.
Published: July 2009

The highest grade orebody in the Dome mine is a steeply dipping 500 m long, 550 m high, and 3.5 m wide banded quartz-fuchsite vein (QFV) accompanied by subsidiary veins in the adjacent wall rock. The QFV is located in a subvertical zone of carbonatized komatiite near a slate unit and is composed of relatively unstrained massive quartz and strained ribbon quartz. Fuchsite and chlorite are the main ribbon components. Native gold, galena and tellurides are typically associated with ribbon quartz, whereas massive quartz is usually low grade.The quartz–fuchsite vein system is coeval with the regional penetrative deformation. Reverse oblique-slip faulting together with an intricate interplay between intermittent variations of the deviatoric stress regime and strain refraction due to layer anisotropy explain the overall anatomy of the vein system. The regional compressive stress regime and the syntectonic wall-rock alteration created the favorable requirements for the combined shear and hydraulic fracturing that led to vein formation.Massive quartz was deposited during prolonged episodes of vein growth, whereas ribbon quartz was emplaced in the course of repetitive and brief periods of crack-seal vein growth. The systematic association of high-grade ore with ribbon quartz suggests a genetic link whereby gold deposition is attributed to small pressure drops accompaning the crack-seal mechanism of vein growth. Thus, gold was introduced along with the bulk of the quartz.
Zeroing tests and application of thermoluminescence dating to Fraser River delta sediments
Authors: Berger Glenn W. , Luternauer John L. , Clague John J.
Published: July 2009

Thermoluminescence (TL) systematics of known-age sediments from the Fraser River delta in southwestern British Columbia have been determined to test the hypothesis that "zeroing" of TL mineral clocks occurs in deltaic and fluvial environments. Analyzed sediments include suspended silt carried by the Fraser River, surface mud from three different environments on the modern Fraser River delta, and independently dated floodplain and prodelta sediments from two cores. Derived TL dating procedures were also applied to unknown-age proglacial muds from one of these cores. The suspended silt and surface muds yielded minimum, relict TL ages of about 300 years, with typical "zero-point" equivalent-dose values of 0.5–1 Gy. Zero-point-corrected TL ages of two samples of Holocene floodplain sediments from one core and two samples of latest Pleistocene – early Holocene prodelta sediments from a second core agree with independent age estimates. In contrast, the older proglacial deposits could not be dated by the TL methods used here because plateaus in equivalent-dose values were not observed.
Sedimentology and development of parabolic dunes, Grande Prairie dune field, Alberta
Authors: Halsey L. A. , Catto N. R. , Rutter N. W.
Published: July 2009

The Grande Prairie dune field in northwest central Alberta is composed of parabolic and dome dunes, presently inactive but which had developed under westerly winds. Two parabolic dune types are recognized on the basis of arm length, nose width, and dune height. Variations in parabolic dune morphology are attributed to spatial and (or) temporal differences in sediment budget as elucidated from sedimentary sequences preserved in the dunes.Seven facies and four subfacies are distinguished from sedimentary sequences examined in nine dune sections. Lee-side deposits of parabolic dunes are typically composed of concave-downward cross-strata that develop from grainfall on a cohesive slipface and are interbedded with avalanche cross-strata. Lee-side deposits interfinger downwind with low-angle to horizontal ripple and grainfall laminations of bottomset deposits and are overlain by shallow-dipping topset deposits. Topset deposits of type 2 parabolic dunes contain sedimentary structures that are indicative of moisture (e.g., adhesion laminae and wet grainfall deposits) and vegetation (e.g., scour surfaces associated with calcareous root tubules) during deposition. These indicators suggest that type 2 parabolic dunes retained sediment effectively, whereas their absence in type 1 parabolic dunes suggests that these dunes did not retain sediment effectively. Type 2 parabolic dunes contain abundant grainfall deposits in topset beds, indicating a high sediment supply, whereas type 1 parabolic do not, suggesting they had a lower sediment supply.
Distribution and tectonic significance of Upper Triassic terranes in the eastern Coast Mountains and adjacent Intermontane Belt, British Columbia
Authors: Rusmore Margaret E. , Woodsworth G. J.
Published: July 2009

New data on Upper Triassic rocks in the eastern Coast Mountains show that it is Stikinia, not Wrangellia, that lies along the eastern margin of the Coast Plutonic Complex, at least as far south as latitude 51°N. These rocks constitute the upper Carnian–lower Norian Mt. Moore formation and the upper Norian Mosley formation. Clinopyroxene-phyric basaltic to andesitic breccia with lesser volcanic sandstone and rare carbonate compose the Mt. Moore formation. The Mosley formation comprises mafic volcaniclastic rocks and limestone. Correlation of these formations with Stikinia is based on similarities in age, stratigraphy, lithology, basalt geochemistry, and inferred tectonic setting.Recognition of Upper Triassic arc-related rocks of the Cadwallader terrane east of its previously known extent indicates that the Cadwallader terrane, rather than Stikinia, underlies much of the southern Intermontane Belt. The revised terrane distribution shows that Stikinia lay west of both the Cadwallader and Bridge River terranes prior to Cretaceous and Tertiary faulting. This configuration supports the idea that the Cadwallader and Stikine terranes represent fragments of a single early Mesozoic arc that was accreted during final closure of the Cache Creek – Bridge River ocean in Middle Jurassic time.
Secular gravity changes: measurements and predictions for selected Canadian sites
Authors: Tushingham A. M. , Lambert A. , Liard J. O. , Peltier W. R.
Published: July 2009

Secular variations in surface gravity (ġ) over Canada are dominated by the Late Wisconsin deglaciation signal. Theoretical modelling of this deglaciation shows that the maximum values for ġ are to be expected around Hudson Bay. Using the JILA-2 absolute gravity apparatus of the Geological Survey of Canada, it should be possible to determine ġ at three sites near Hudson Bay by about 1993 and at more sites soon afterward. Secular rates of the ongoing postglacial-adjustment process will soon be determined at inland sites where no contemporary rates have been available.
Mineralogy and genesis of calc-silicates associated with Archean volcanogenic massive sulphide deposits at the Manitouwadge mining camp, Ontario
Authors: Pan Yuanming , Fleet Michael E.
Published: July 2009

Skarn-like calc-silicate rocks are reported in spatial association with the Archean Cu–Zn–Ag massive sulphide deposits at the Manitouwadge mining camp, Ontario. Calc-silicates in the footwall of the Willroy mine occur as matrix to breccia fragments of garnetiferous quartzo-feldspathic gneiss and as lenses within garnetiferous quartzo-feldspathic gneiss and are composed of clinopyroxene, garnet, calcic amphiboles, wollastonite, plagioclase, K-feldspar, epidote, quartz, calcite, magnetite, and minor sulphides. Calc-silicates within the main orebody of the Geco mine are characterized by clinopyroxene, calcic amphiboles (Cl–K-rich hastingsitic and ferro-edenitic hornblende, ferro-edenite (up to 4.7 wt.% Cl); and ferroactinolite (6.7 wt.% MnO)), garnet, epidote (including an epidote rich in rare-earth elements and Cl), calcite, quartz, and abundant sulphides. Calc-silicates within the basal 4/2 Copper Zone of the Geco mine contain garnet, gahnite, sphalerite, ferroactinolite (8.5 wt.% MnO), epidote, quartz, biotite, plagioclase, chlorite, muscovite, K-feldspar, and pyrosmalite (with Mn/(Mn + Fe) ratio ranging from 0.21 to 0.61, and up to 3.9 wt.% Cl). The calc-silicates probably represent metasomatic remobilization of dispersed Ca (and Cl) from sea-floor hydrothermal alteration of mafic to intermediate volcanic rocks and are only indirectly related to the hypothesized syngenetic ore-forming processes for the associated base metal sulphide deposits. The calc-silicates formed initially at about 600 °C and 3–5 kbar (1 kbar = 100 MPa) in a mildly reducing environment (from 1 log unit above to 1 log unit below the fayalite–magnetite–quartz buffer) during the upper-amphibolite- to granulite-facies regional metamorphism and were altered subsequently at lower temperatures (<500 °C).
Deformation till in the Great Lakes region: implications for rapid flow along the south-central margin of the Laurentide Ice Sheet
Authors: Hicock Stephen R. , Dreimanis Aleksis
Published: July 2009

Structural and lithologic data indicate that, while deposited under actively moving ice, considerable portions of three muddy calcareous subglacial tills in the Great Lakes region probably experienced some component of ductile deformation. Viscous till flow and ductile shear are invoked to explain a combination of features such as recumbent isoclinal folds, unlithified sediment clasts, mixed ostracode shells, reversed stone lee ends, girdle and transverse fabrics, irregular stone pavements, fine striae following stone curves, and inconsistent stone striae and a-axes. Deforming, fine-textured subglacial till is considered as a subhorizontal shear zone, rheologically layered with associated structures (in descending order): ductile (e.g., isoclinal folds), brittle–ductile (e.g., fissility), and brittle (e.g., till wedges). Rheology would be controlled mainly by till pore water content, matrix texture, and stone content. Spatial and temporal superposition of rheologies and subglacial processes probably occurred while some fine tills were forming. Fine deformation till may be especially common around areas of the Great Lakes region where proglacial mud and weak bedrock were remoulded as ice travelled along major basins and troughs. In such areas, under a wet-based glacier, resulting till would have been too weak to sustain a large shear stress or inhibit rapid ice flow over it. Instead, in these places, the till was probably water saturated, accounting for most of the glacial flow, and protected the substrate from extensive deformation while effectively acting as a lubricant to overriding ice. Areas of fine deformation till probably represent areas of former low subglacial fluid conductivity and rapid glacial flow. In other areas, subglacial sheet flow of meltwater may have accelerated glacial flow. These two types of areas may have been connected at times under zones of ice streaming and (or) surging.
The taxonomic position of Anningia megalops, a small amniote from the Permian of South Africa
Authors: Reisz Robert R. , Dilkes David W.
Published: July 2009

Anningia megalops Broom, 1927 is based upon a poorly preserved, incomplete skull and was interpreted originally as an intermediate form between therapsids and primitive nontherapsid synapsids (pelycosaurs). Restudy of the type specimen indicates that A. megalops is a nondiagnosable primitive synapsid and is, therefore, declared to be a nomen vanum.
Port Bruce ice-flow directions based on heavy-mineral assemblages in tills from the south shore of Lake Erie in Ohio
Authors: Hofer John W. , Szabo John P.
Published: July 2009

The flow directions of ice lobes within the Erie basin may be deduced from heavy-mineral assemblages of the Hayesville, Hiram, and Ashtabula tills deposited during the Port Bruce Stade after the Erie Interstade. These tills have heavy-mineral assemblages dominated by purple garnet, green hornblende, and clinopyroxene. Oolitic hematite occurs in all tills, but is dominant in the Ashtabula Till. The probable source of hematite is the Furnaceville Ironstone Member of the Clinton Group which crops out south of Lake Ontario. Trilinear plots of purple garnet – red garnet – epidote suggest that the eastern Grenville Subprovince is the provenance of all three tills. Southwestward-flowing ice of an Ontario–Erie lobe deposited these tills in the Erie basin. The Huron–Erie lobe did not deposit tills along the south shore of Lake Erie after the Erie Interstade.
The Hillsborough, New Brunswick, mastodon and comments on other Pleistocene mastodon fossils from Nova Scotia
Authors: Harington C. R. , Grant D. R. , Mott R. J.
Published: July 2009

This is the first detailed description of the remains of a young adult American mastodon (Mammut americanum) found in 1936 in peaty silt and clay underlying till in gypsum karst near Hillsborough, New Brunswick. It documents 312 fossils comprising a partial skull with molar teeth and tusks, a neck vertebra, and much of the right postcranial skeleton. An individual age of 15 – 18 years and a weight of 8.3 t are estimated for this mastodon. Associated spheroids, containing cut wood fragments and an unusually high clay content, are interpreted to be mastodon coprolites. Radiocarbon ages are 13 600 ± 200 (bone), 37 200 ± 1 310 (coprolite wood), 51 500 ± 1 270 (coprolite carbonate cement), and >43 000 BP (peat). Pollen in the coprolites and associated sediment indicates a coniferous forest. Nine other mastodon fossils from Nova Scotia include a femur from Middle River, which dates 31 300 ± 500 BP and contains pollen representing boreal forest – tundra, and three molars from offshore Georges Bank. All ages are judged minimal: the older four are at or near the limit of the method; the younger is likely incorrect because of preservative contamination. Associated pollen assemblages correlate with late last interglacial age deposits in the region and differ from possible Middle Wisconsinan age deposits. The fossils are regarded as a single group and are assigned to a cool phase of the Sangamonian interglaciation, probably oxygen-isotope substage 5a, prior to Wisconsinan glaciation.
An Early Cambrian deltaic–fluvial model for an Iapetan rift-arm drainage system, southeastern Quebec
Authors: Marquis Robert , Kumarapeli P. Stephen
Published: July 2009

Based on the model that during the rifting stage beginning at ca. 590 Ma, the Ottawa Graben, an Iapetan failed arm, localized a large river that flowed into the nascent Iapetus, a search was made for the related fluvial and deltaic deposits. The search led to the identification of fluvial deposits as predicted by the model. Deltaic deposits were also identified despite complications brought about by deformation, metamorphism, and thrusting, although they probably belong to a late phase of delta buildup in the Early Cambrian. Older deltaic deposits of the river probably lie buried beneath a volcanic shield that built up at the proximal end of the graben ca. 554 Ma. The successful application of the model supports the paradigm of rift-arm – failed-arm rivers and their deltas as proposed by K. Burke and J.F. Dewey nearly two decades ago. Investigations based on this paradigm, in appropriate geological situations, may provide insights into problems related to continental rifting and breakup and provide information for the reconstruction of ancient rift–rift–rift (rrr) triple junctions and plate boundaries.
Northeast-trending Early Proterozoic dykes of southern Superior Province: multiple episodes of emplacement recognized from integrated paleomagnetism and U–Pb geochronology
Authors: Buchan K. L. , Mortensen J. K. , Card K. D.
Published: July 2009

Integrated paleomagnetic and U–Pb geochronologic studies have been conducted to establish the paleomagnetic directions and ages of Early Proterozoic tholeiitic dykes of northeast trend in the southern Superior Province, previously referred to collectively as Preissac dykes. It is demonstrated that they are readily separated on the basis of paleomagnetism into subsets, referred to as the Biscotasing and Senneterre swarms. In addition a pair of unnamed dykes may be associated with the north-and northwest-trending Matachewan swarm farther west.Biscotasing dykes have a down-west magnetization of single polarity with a corresponding paleopole at 27.8°N, 136.7°W (dm = 12.3° and dp = 9.4°). Senneterre dykes carry an up-north (or occasionally down-south) direction with corresponding paleopole at 15.3°S, 75.7°W (dm = 7.0°, dp = 4.4°). The Senneterre direction is indistinguishable from the primary N1 remanence direction that dominates the magnetization of Nipissing sills of the Southern Province. Paleomagnetic field tests described herein or in earlier studies indicate that Biscotasing and Senneterre directions are primary and, hence, that two ages of intrusion are involved, with the age of Senneterre dykes coinciding with the intrusion of most Nipissing sills. U–Pb dating of baddeleyite conducted at a paleomagnetic sampling site yields an age of 2214.3 ± 12.4 Ma for the Senneterre swarm, indistinguishable from the age of 2217.2 ± 4 Ma reported from an N1 Nipissing sill site in another study. A U–Pb age on baddeleyite and zircon of 2166.7 ± 1.4 Ma was obtained from a paleomagnetic site in the Biscotasing swarm. The primary paleopoles for the Senneterre, Nipissing, and Biscotasing rocks define a direction of polar wander opposite to that of the most widely used polar wander paths for North America for this period, suggesting that these paths should no longer be used.
ETA-NUCLEUS INTERACTION STUDIES: EXPERIMENTAL EFFORTS
Authors:   for the COSY-GEM collaboration, ROY B. J.
Published: July 2009

The idea that the η meson could form a bound system with nucleus was put forward long ago by Q.Haider and L.C.Liu and was based on the observation that the low energy η-nucleon interaction was attractive. Since then a number of theoretical calculations have been performed to the predict eta-nucleus bound states. Such bound states-the so called "eta-mesic nuclei" - are predicted to have finite widths and will eventually decay. The experimental confirmation of such a quasi-bound system would be a very useful tool for investigation of interaction between a short lived eta-meson and the nucleus. Since the eta-mesons can not be produced as a secondary beam, the eta-meson particles are available for investigations only as products of certain nuclear reactions where they appear as final state particles. The final state interaction(FSI) effects are the only source of information about the eta-meson interaction with the nucleus. Experiments were performed at the cooler synchrotron accelerator, COSY, Juelich using dedicated detection systems to study the eta-nucleus interaction. The present talk summarizes the status of previous experimental searches. Some preliminary results of the experiments performed at COSY on the eta-nucleus FSI studies are also presented here. The details of the experiments done at COSY, Juelich on eta-mesic nuclei searches along with recent results are reported in an another communication in this proceedings.
ASYMPTOTIC PROPERTIES FOR A SEMILINEAR PLATE EQUATION IN UNBOUNDED DOMAINS
Authors: DA LUZ CLEVERSON ROBERTO , CHARÃO RUY COIMBRA
Published: July 2009

We study the existence, uniqueness, and asymptotic properties of global solutions to the initial value problem associated with a semilinear, dissipative, plate equation under rotational inertia effects in ℝn. We obtain polynomial decay rate in time for the total energy. In dimension n ≥ 5 for the linear problem and n = 5 for the semilinear problem with small data, we obtain fast decay of the total energy and a decay rate t-1/2for L2-norm of the solution and similar decay rates for the L2-norm of higher-order derivatives.
ESTIMATES FOR THE MAXWELL FIELD NEAR THE SPATIAL AND NULL INFINITY OF THE SCHWARZSCHILD SPACETIME
Authors: VALIENTE KROON JUAN ANTONIO
Published: July 2009

It is shown how the gauge of the "regular finite initial value problem at spacelike infinity" can be used to construct a certain type of estimates for the Maxwell field propagating on a Schwarzschild background. These estimates are constructed with the objective of obtaining information about the smoothness near spacelike and null infinity of a wide class of solutions to the Maxwell equations.
Implanted Neural Interfaces: Biochallenges and Engineered Solutions
Authors: Grill Warren M. , Norman Sharon E. , Bellamkonda Ravi V.
Published: July 2009

Neural interfaces are connections that enable two-way exchange of information with the nervous system. These connections can occur at multiple levels, including with peripheral nerves, with the spinal cord, or with the brain; in many instances, fundamental biophysical and biological challenges are shared across these levels. We review these challenges, including selectivity, stability, resolution versus invasiveness, implant-induced injury, and the host-interface response. Subsequently, we review the engineered solutions to these challenges, including electrode designs and geometry, stimulation waveforms, materials, and surface modifications. Finally, we consider emerging opportunities to improve neural interfaces, including cellular-level silicon to neuron connections, optical stimulation, and approaches to control inflammation. Overcoming the biophysical and biological challenges will enable effective high-density neural interfaces for stimulation and recording.
The Influence of Muscle Physiology and Advanced Technology on Sports Performance
Authors: Neptune Richard R. , McGowan Craig P. , Fiandt John M.
Published: July 2009

Muscle mechanical output such as force and power are governed by highly nonlinear intrinsic muscle properties associated with different muscle fiber types and are influenced by training and age. Many of the interactions between these properties pose trade-offs such that an individual's anthropometrics and muscle morphology may allow an athlete to excel in one sport but not in others. Advanced modeling and simulation techniques are powerful tools to gain insight into performance limits, optimal equipment designs, and mechanisms that may lead to injury. Recent technological innovations have produced faster running tracks, bicycles, speed skates, and swimming pools. This review discusses the influence of intrinsic muscle properties in sports and how advanced technology can be used to extend the limits of human performance.
Patient-Specific Modeling of Cardiovascular Mechanics
Authors: Taylor C.A. , Figueroa C.A.
Published: July 2009

Advances in numerical methods and three-dimensional imaging techniques have enabled the quantification of cardiovascular mechanics in subject-specific anatomic and physiologic models. Patient-specific models are being used to guide cell culture and animal experiments and test hypotheses related to the role of biomechanical factors in vascular diseases. Furthermore, biomechanical models based on noninvasive medical imaging could provide invaluable data on the in vivo service environment where cardiovascular devices are employed and on the effect of the devices on physiologic function. Finally, patient-specific modeling has enabled an entirely new application of cardiovascular mechanics, namely predicting outcomes of alternate therapeutic interventions for individual patients. We review methods to create anatomic and physiologic models, obtain properties, assign boundary conditions, and solve the equations governing blood flow and vessel wall dynamics. Applications of patient-specific models of cardiovascular mechanics are presented, followed by a discussion of the challenges and opportunities that lie ahead.
Ingestion of whey hydrolysate, casein, or soy protein isolate: effects on mixed muscle protein synthesis at rest and following resistance exercise in young men
Authors: Tang Jason E. , Moore Daniel R. , Kujbida Gregory W. , Tarnopolsky Mark A. , Phillips Stuart M.
Published: July 2009

This study was designed to compare the acute response of mixed muscle protein synthesis (MPS) to rapidly (i.e., whey hydrolysate and soy) and slowly (i.e., micellar casein) digested proteins both at rest and after resistance exercise. Three groups of healthy young men ( n = 6 per group) performed a bout of unilateral leg resistance exercise followed by the consumption of a drink containing an equivalent content of essential amino acids (10 g) as either whey hydrolysate, micellar casein, or soy protein isolate. Mixed MPS was determined by a primed constant infusion of l-[ ring-13C6]phenylalanine. Ingestion of whey protein resulted in a larger increase in blood essential amino acid, branched-chain amino acid, and leucine concentrations than either casein or soy (P < 0.05). Mixed MPS at rest (determined in the nonexercised leg) was higher with ingestion of faster proteins (whey = 0.091 ± 0.015, soy = 0.078 ± 0.014, casein = 0.047 ± 0.008%/h); MPS after consumption of whey was ∼93% greater than casein (P < 0.01) and ∼18% greater than soy (P = 0.067). A similar result was observed after exercise (whey > soy > casein); MPS following whey consumption was ∼122% greater than casein (P < 0.01) and 31% greater than soy (P < 0.05). MPS was also greater with soy consumption at rest (64%) and following resistance exercise (69%) compared with casein (both P < 0.01). We conclude that the feeding-induced simulation of MPS in young men is greater after whey hydrolysate or soy protein consumption than casein both at rest and after resistance exercise; moreover, despite both being fast proteins, whey hydrolysate stimulated MPS to a greater degree than soy after resistance exercise. These differences may be related to how quickly the proteins are digested (i.e., fast vs. slow) or possibly to small differences in leucine content of each protein.
Impact of elevated pulmonary blood flow and capillary pressure on lung responsiveness
Authors: Peták Ferenc , Janosi Tibor Z. , Myers Carole , Fontao Fabienne , Habre Walid
Published: July 2009

Since alterations in pulmonary hemodynamics may lead to airway hyperreactivity, the consequences of individual changes in pulmonary blood flow (Q̇p) and capillary pressure (Pc) on lung responsiveness were investigated. During maintenance of a steady-state Pc of 5, 10, or 15 mmHg ( groups 1–3), acute increases of Q̇p were generated in isolated, perfused rat lungs by simultaneous pulmonary arterial pressure elevation and venous pressure lowering. Conversely, at constant low ( groups 4 and 5) or high Q̇p ( groups 6 and 7), Pc was lowered or elevated by changing, in parallel, the pulmonary arterial and venous pressures. Pulmonary input impedance was measured under baseline conditions and during methacholine provocation (2–18 μg·kg−1·min−1), whereas the pulmonary hemodynamics were altered in accordance with the group allocation. The airway resistance and constant-phase parenchymal model parameters were identified from the pulmonary input impedance spectra. Increases of Q̇p at constant Pc had no effect on the basal lung mechanics, whereas they enhanced the lung reactivity to methacholine, particularly when high Pc was maintained [peak airway resistance increases of 299 ± 99% (SE) vs. 609 ± 217% at Q̇p levels of 5 and 10 ml/min, respectively, P < 0.05]. In contrast, the change of Pc at constant Q̇p slightly deteriorated the basal parenchymal mechanics without affecting the lung responsiveness. These findings suggest that increases in Q̇p per se may lead to the development of airway hyperreactivity. This phenomenon may contribute to the airway susceptibility under conditions associated with simultaneous elevations in pulmonary vascular pressures and Q̇p, such as exercise-induced asthma and the situation in children with congenital heart diseases.
A unique micromechanocalorimeter for simultaneous measurement of heat rate and force production of cardiac trabeculae carneae
Authors: Han June-Chiew , Taberner Andrew J. , Kirton Robert S. , Nielsen Poul M. , Smith Nicholas P. , Loiselle Denis S.
Published: July 2009

To study cardiac muscle energetics quantitatively, it is of paramount importance to measure, simultaneously, mechanical and thermal performance. Ideally, this should be achieved under conditions that minimize the risk of tissue anoxia, especially under high rates of energy expenditure. In vitro, this consideration necessitates the use of preparations of small radial dimensions. To that end, we have constructed a unique micromechanocalorimeter, consisting of an open-ended flow-through microcalorimeter, a force transducer, and a pair of muscle-length actuators. The device enables the metabolic and mechanical performance of cardiac trabeculae carneae to be investigated for prolonged periods in a continuously replenished oxygen- and nutrient-rich environment.
Protein and carbohydrate supplementation after exercise increases plasma volume and albumin content in older and young men
Authors: Okazaki Kazunobu , Hayase Hideki , Ichinose Takashi , Mitono Hiroyuki , Doi Tatsuya , Nose Hiroshi
Published: July 2009

This study examined whether increased plasma volume (PV) and albumin content (Albcont) in plasma for 23 h after exercise were attenuated in older subjects compared with in young adult subjects, and if this attenuation abated by supplementation with protein and carbohydrate (CHO) immediately after exercise. Eight moderately active older (∼68 yr) and 8 young (∼21 yr) men performed two trials: control (CNT) and Pro-CHO in which subjects consumed placebo (0.5 kcal, 0 g protein, 0.5 mg Na+ in 3.2 ml total fluid volume/kg body wt) or protein and CHO mixture (3.2 kcal, 0.18 g protein, 0.5 mg Na+ in 3.2 ml total fluid volume/kg body wt) supplementations, respectively, immediately after high-intensity interval exercise for 72 min [8 sets of 4 min at 70–80% peak oxygen consumption rate (V̇o2peak) intermitted by 5 min at 20% V̇o2peak]. PV, Albcont, and plasma globulin content (Glbcont) were measured before exercise, at the end of exercise, every hour from the 1st to the 5th hour after exercise, and at the 23rd hour after exercise. From 12 h before the start to the end of experiment, food intake was controlled to the age-matched recommended dietary allowances. We found that during the first 4 h after exercise in CNT, Albcont recovered less in the older than the young group by ∼0.04 g/kg ( P < 0.05), while it generally recovered more with Pro-CHO than CNT by ∼0.09 and ∼0.04 g/kg in the young and older group, respectively, accompanied by a greater increase in PV by ∼1 and ∼2 ml/kg, respectively, during the 23 h after exercise ( P < 0.05). Glbcont remained constant throughout the experiment in both trials for both age groups. Thus the attenuated responses of Albcont and PV after exercise in older subjects were restored by protein and CHO supplementation immediately after exercise, similarly to young subjects.
LKB1 and AMPK Family Signaling: The Intimate Link Between Cell Polarity and Energy Metabolism
Authors: Jansen Marnix , ten Klooster Jean Paul , Offerhaus G. Johan , Clevers Hans
Published: July 2009

Research on the LKB1 tumor suppressor protein mutated in cancer-prone Peutz-Jeghers patients has continued at a feverish pace following exciting developments linking energy metabolism and cancer development. This review summarizes the current state of research on the LKB1 tumor suppressor. The weight of the evidence currently indicates an evolutionary conserved role for the protein in the regulation of various aspects of cellular polarity and energy metabolism. We focus on studies examining the concept that both cellular polarity and energy metabolism are regulated through the conserved LKB1-AMPK signal transduction pathway. Recent studies from a variety of model organisms have given new insight into the mechanism of polyp development and cancer formation in Peutz-Jeghers patients and the role of LKB1 mutation in sporadic tumorigenesis. Conditional LKB1 mouse models have outlined a tissue-dependent context for pathway activation and suggest that LKB1 may affect different AMPK isoforms independently. Elucidation of the molecular mechanism responsible for Peutz-Jeghers syndrome will undoubtedly reveal important insight into cancer development in the larger population.
Mitochondrial Dynamics in Mammalian Health and Disease
Authors: Liesa Marc , Palacín Manuel , Zorzano Antonio
Published: July 2009

The meaning of the word mitochondrion (from the Greek mitos, meaning thread, and chondros, grain) illustrates that the heterogeneity of mitochondrial morphology has been known since the first descriptions of this organelle. Such a heterogeneous morphology is explained by the dynamic nature of mitochondria. Mitochondrial dynamics is a concept that includes the movement of mitochondria along the cytoskeleton, the regulation of mitochondrial architecture (morphology and distribution), and connectivity mediated by tethering and fusion/fission events. The relevance of these events in mitochondrial and cell physiology has been partially unraveled after the identification of the genes responsible for mitochondrial fusion and fission. Furthermore, during the last decade, it has been identified that mutations in two mitochondrial fusion genes ( MFN2 and OPA1) cause prevalent neurodegenerative diseases (Charcot-Marie Tooth type 2A and Kjer disease/autosomal dominant optic atrophy). In addition, other diseases such as type 2 diabetes or vascular proliferative disorders show impaired MFN2 expression. Altogether, these findings have established mitochondrial dynamics as a consolidated area in cellular physiology. Here we review the most significant findings in the field of mitochondrial dynamics in mammalian cells and their implication in human pathologies.
Stability and Convergence Results Based on Fixed Point Theory for a Generalized Viscosity Iterative Scheme
Authors: De la Sen M.
Published: July 2009

A generalization of Halpern's iteration is investigated on a compact convex subset of a smooth Banach space. The modified iteration process consists of a combination of a viscosity term, an external sequence, and a continuous nondecreasing function of a distance of points of an external sequence, which is not necessarily related to the solution of Halpern's iteration, a contractive mapping, and a nonexpansive one. The sum of the real coefficient sequences of four of the above terms is not required to be unity at each sample but it is assumed to converge asymptotically to unity. Halpern's iteration solution is proven to converge strongly to a unique fixed point of the asymptotically nonexpansive mapping.
IL-4 Deficiency Decreases Mortality but Increases Severity of Arthritis in Experimental Group BStreptococcusInfection
Authors: Tissi Luciana , Bistoni Francesco , Puliti Manuela
Published: July 2009

IL-4 is an anti-inflammatory cytokine that inhibits the onset and severity in different experimental arthritis models. Group B streptococci (GBS) have been recognized as an ever-growing cause of serious invasive infections in nonpregnant adults. Septic arthritis is a clinical manifestation of GBS infection. To investigate the role of IL-4 in experimental GBS infection, IL-4 deficient or competent mice were inoculated with1×107GBS/mouse. Mortality, appearance of arthritis, GBS growth in the organs, and local and systemic cytokine and chemokine production were examined. IL-4–/– mice showed lower mortality rates but increased severity of arthritis and exhibited a lower microbial load in blood, kidneys, and joints than wt mice. Increased local levels of IL-1β, IL-6, TNF-α, MIP-1α, and MIP-2 accompanied the more severe arthritis in IL-4–/– mice. Our results suggest a detrimental role of IL-4 in GBS sepsis, whereas it plays a beneficial effect on GBS-induced arthritis.
Drug-Induced Hematologic Syndromes
Authors: Mintzer David M. , Billet Shira N. , Chmielewski Lauren
Published: July 2009

Objective. Drugs can induce almost the entire spectrum of hematologic disorders, affecting white cells, red cells, platelets, and the coagulation system. This paper aims to emphasize the broad range of drug-induced hematological syndromes and to highlight some of the newer drugs and syndromes.Methods. Medline literature on drug-induced hematologic syndromes was reviewed. Most reports and reviews focus on individual drugs or cytopenias.Results. Drug-induced syndromes include hemolytic anemias, methemoglobinemia, red cell aplasia, sideroblastic anemia, megaloblastic anemia, polycythemia, aplastic anemia, leukocytosis, neutropenia, eosinophilia, immune thrombocytopenia, microangiopathic syndromes, hypercoagulability, hypoprothrombinemia, circulating anticoagulants, myelodysplasia, and acute leukemia. Some of the classic drugs known to cause hematologic abnormalities have been replaced by newer drugs, including biologics, accompanied by their own syndromes and unintended side effects.Conclusions. Drugs can induce toxicities spanning many hematologic syndromes, mediated by a variety of mechanisms. Physicians need to be alert to the potential for iatrogenic drug-induced hematologic complications.