bluuebunny/crossref_metadata_2025 huggingface dataset:
A Middle Ordovician conodont faunule from the Tetagouche Group, Camel Back Mountain, New Brunswick
Authors: Kennedy D. J. , Barnes C. R. , Uyeno T. T.
Published: June 2009

The Tetagouche Group is a 10 000 m geosynclinal sequence of slates, greywackes, rhyolite tuffs, and greenstones underlying parts of northern New Brunswick. It hosts the well-known stratabound massive sulphide deposits of the Bathurst–Newcastle mining area. Few fossils have been found in the group and its age is poorly known. More than 890 conodonts have been recovered from a locality near Camel Back Mountain in the Metabasalt unit. Coelocerodontus? lacrimosus and Protopanderodus liripipus are described as new species. The faunule contains species indicative of the Prioniodis alobatus Subzone of the Amorphognathus tvaerensis Zone and is the first record of the subzone in North America. The subzone equates with the middle Caradocian (approximately the Soudleyan Stage) or late Wildernessian Stage of the Middle Ordovician Epoch. During this interval the Proto-Atlantic Ocean is considered to have been undergoing closure, hence recent interpretations that regard the Metabasalt unit as forming during an earlier phase of opening must be reexamined.
Magnetic daily variations compared between the east and west coasts of Canada
Authors: Lilley F. E. M.
Published: June 2009

Magnetic observatory data from St. John's, on the Atlantic seaboard of Canada, and Victoria, near the Pacific seaboard, are analysed for coast effects at diurnal periods by comparison with similar records from inland observatories. The five international quiet days of August 1968 are studied. When resolved to geographic coordinates and adjusted to local solar time, the horizontal components of the daily variation are spatially uniform across the continent, but the vertical components vary greatly. Subtracting the vertical signal recorded at Ottawa (inland) from that recorded at St. John's demonstrates a long-period coast effect, with an anomalous vertical component leading the cross-shore horizontal component in phase by about an eighth of a cycle. Subtracting the vertical signal at Newport (inland) from that at Victoria demonstrates a similar but lesser effect. These results are consistent with the diurnal coast effect observed for two coasts of the Australian continent and for California. A Parkinson-type coast effect is interpreted to occur at the long periods of the daily variation, in addition to the substorm periods at which it has traditionally been observed.Separate from the coast effect, there is a substantial difference in the daily-variation vertical component between the two inland stations of Ottawa and Newport. This difference may be caused by a change in typical source-current configuration from one station to the other or it may indicate a contrast in electrical conductivity between the two inland regions of the continent. In the latter case the indication would be of higher conductivity to the east and lower conductivity to the west, the reverse of many currently accepted models.
Lits de bryophytes du Wisconsin moyen, Vallée-Jonction, Québec
Authors: LaSalle Pierre , Martineau Ghismond , Chauvin Luc
Published: June 2009

A shallow-water bryophyte arctic to subarctic assemblage, collected in what appears to be shallow-water lake sediments, has been dated at greater than 39 000 14C years BP (QU-327). It is probably correlative with the Massawipi (St. Pierre) formation.
Contemporary crustal movements in Canada
Authors: Lambert A. , Vaníček P.
Published: June 2009

Our present knowledge of the patterns and causes of contemporary aseismic movements of the crust in Canada is reviewed. Modern and paleo water-level data and geodetic relevelling data are being used to delineate the regional pattern of vertical movements, but equivalent data on regional horizontal movements are not yet available. The first steps are being taken to relate the emerging regional pattern of vertical movement in Canada to the interactions on the western margin of the America plate and to the spatial variations in seismicity, gravity field, and crustal stress in the plate interior. Viscoelastic modelling of the earth's response to surface loads, and laboratory-based results on possible non-linear rheologies in the mantle have provided a useful theoretical framework for comparing new data on ice-sheet histories with paleo water-level results. Local-scale crustal deformations are being monitored by triangulation, levelling, and gravity networks, as well as by tiltmeters, strainmeters and well-water-level meters. The interpretation of the local deformation data has been facilitated by modelling of the response of inhomogencous-elastic and porous-elastic media. The level of research activity on local aseismic movements in different areas of Canada corresponds to the seismotectonic significance of the areas.
A reinterpretation of glacial and marine limits around the northwestern Laurentide Ice Sheet
Authors: Dyke Arthur S.
Published: June 2009

Seven new radiocarbon dates pertaining to deglaciation of northern Prince of Wales Island place the margin of the Laurentide Ice Sheet on the island by 11 000 BP. This requires a revision of the proposed age for the Viscount Melville Sound Ice Shelf of 10 300 – 9880 BP. A revised age of 11 300 – 11 000 BP is suggested.The new dates also require revisions of the proposed Wisconsinan and Holocene history of Banks Island. Shells thought to have been thrust onshore to an elevation of 88 m by the ice shelf on northern Banks Island after 10 600 BP are reinterpreted as undisturbed postglacial marine shells recording a relative sea level of 88 m or more. This, in turn, suggests that the East Coast Sea and Jesse Till are of Late Wisconsinan rather than Early Wisconsinan age and that the Late Wisconsinan glacial limit on Banks Island as figured on the 1968 Glacial Map of Canada, rather than on recent revisions, is essentially correct.
Wolverine from the Pleistocene of the Yukon: evolutionary trends and taxonomy of Gulo (Carnivora: Mustelidae)
Authors: Bryant Harold N.
Published: June 2009

Dental and mandibular measurements on a sample of Gulo gulo of possible Sangamonian to Wisconsinan age from the Old Crow Basin in the Yukon average 2.7% smaller than comparable measurements of the extant form. The difference in the width of P4 is statistically significant. These results do not differ significantly from Harington's previous analysis of a similar sample from Old Crow, and comparable data from the two studies were pooled. Dimensions in the pooled fossil sample average 4.3% smaller; differences in the length and width of both P4 and M1, and the length of the P4–M1, tooth row are significant. Bivariate analysis indicates that P2 and P4 are significantly narrower in the fossil sample. Old Crow wolverines conform to the general trend of increasing size and broadening of certain teeth, especially P4, from the mid-Pleistocene appearance of Gulo in Europe and North America to the end of the Wisconsinan. Referral of the small mid-Pleistocene Gulo to a distinct chronospecies, G. schlosseri, is questioned based on fluctuations in the size of the teeth and the variation associated with other trends in dental morphology in wolverine populations during the Quaternary in Europe and North America.
Holocene sea levels, paleoceanography, and late glacial ice configuration near the Northumberland Strait, Maritime Provinces
Authors: Scott David B. , Medioli Franco S. , Miller Ann A. L.
Published: June 2009

Work on new cores from old core sites in Baie Verte, New Brunswick, led to the identification of submerged salt-marsh peats, reported earlier as freshwater ones. A comprehensive sea-level curve, between 9 and 15 m below present, is based on marsh foraminiferal assemblages. These data indicate that between 4500 and 5400 BP relative sea-level (RSL) rise was comparatively slow (about 10 cm/100 years); the rate increased dramatically between 4500 and 4000 BP (1 m/100 years) and decreased between 2000 and 4000 BP to its present rate of 15 cm/100 years. We suggest RSL was falling before 5400 BP and that the sequence in our deepest core is similar to some observed in the Bay of Fundy and Nova Scotian Atlantic coast where early RSL fall is documented. To account for this sea-level record and others nearby we suggest that the ice history here is complex, with three separate ice caps thinning towards this area in late glacial times.Earlier work also indicated a number of sediment sequences barren of benthonic foraminifera, suggesting a complex marine–freshwater history for the area. The study of new cores containing the same sequences indicates no barren zones but a simple transgressive sequence with a warm-water calcareous fauna followed by an agglutinated transitional estuarine foraminiferal fauna.
A new genus and subgenus and two new species of latest Jurassic oxytomid bivalves from Arctic Canada
Authors: Jeletzky J. A. , Poulton T. P.
Published: June 2009

Uppermost Jurassic (Volgian) rocks of the western Canadian Arctic Islands and northwestern mainland Canada contain rich faunas that include two oxytomid bivalves that are described as specifically and generically new: Canadotis canadensis n. gen., n. sp. and Arctotis (Canadarctotis) srugosa n. subgen., n. sp. The former is thought to be a derivative of an ancestral Meleagrinella-like Late Triassic or Early Jurassic bivalve; the latter is a development from mid-Jurassic Arctotis s.s. species. Both are important markers for the early Volgian in northern and northwestern Canada.
The Northwest Atlantic Mid-Ocean Channel of the Labrador Sea. IV. Petrography and provenance of the sediments
Authors: Chough Sung Kwun , Hesse Reinhard , Müller Jens
Published: June 2009

The Northwest Atlantic Mid-Ocean Channel (NAMOC) of the Labrador Sea is associated with a 500 m thick sequence of well-bedded turbidites along the axis of the Labrador and Newfoundland basins and extends onto the western Sohm Abyssal Plain. The specific source areas of these terrigenous turbidites on the shelves and landmasses surrounding the Labrador Sea were not known hitherto because the morphological connections in the head region of the NAMOC with canyons on the slope are masked by young ice-rafted and bottom-current-transported sediments.Petrographic analysis of channel sands and gravels suggests a dominant Canadian source for the channel segment north of the confluence with the Imarssuak Mid-Ocean Channel (IMOC) based on the predominance of lower Paleozoic detrital carbonates. The IMOC provides sediment from sources around the West Reykjanes Basin, i.e., the east coast of Greenland and Iceland; however, source-specific minerals or rock fragments from the Tertiary alkali basalts of southwest Greenland were not detected. Anorthosite pebbles imply a Canadian rather than a Greenlandian source, based on the relatively low anorthite content (An25–45) of their plagioclases.In the silt- and clay-sized fractions turbidites are distinctly different from intercalated pelagic oozes by their high detrital carbonate and organic matter contents and low to zero contents of montmorillonite. Organic carbon concentrations (0.8–1.0%) of the muddy spill-over turbidites on the levees of NAMOC are sufficient for hydrocarbon source rocks; their association with coarse-grained channel sediments would make them interesting exploration targets if they occurred in shallower water in the subsurface.
Petrology of Upper Ordovician – Lower Silurian rocks of the Antigonish Highlands, Nova Scotia
Authors: Murphy J. B.
Published: June 2009

Upper Ordovician to Lower Silurian rocks in the Antigonish Highlands consist of interlayered basalts, rhyodacites, arkoses, and conglomerates overlain by a thick sequence of marine clastic rocks and minor rhyolites. The stratigraphy documents a marine transgression. The volcanic rocks were deposited in a within-plate, continental, extensional environment. The basalts display alkalic and tholeiitic affinities, and the rhyodacites were formed by anatexis of the crust. The origin of the younger rhyolites is not clear: they are compositionally distinct from the rhyodacites but may be related to them as late-stage differentiates. At present, it is not possible to evaluate whether the tectonic setting and magmatic affinities are regionally or locally controlled.The geological history is very similar to that of Lower Silurian rocks immediately north of the Antigonish Highlands at Arisaig. In the simplest sense, this indicates these areas may have been juxtaposed prior to the Late Ordovician and limits cumulative post-Silurian movement on the boundary (Hollow) fault to about 40 km.
Loading of a large diamicton mass in glacial Lake Maumee III sediments, southwestern Ontario
Authors: Stewart Robert A.
Published: June 2009

An 8 m long pod-shaped mass of deformed diamicton and sand occurs in Lake Maumee III glaciolacustrine sediments of the Port Stanley Drift, near Port Bruce, Ontario. Sedimentary structures observed in the diamicton mass and enclosing sands indicate large-scale loading accompanied their deposition. The lithology of the mass resembles admixed Port Stanley and Catfish Creek tills, which occur in moraines and other bodies of drift nearby. The diamicton mass may have been deposited en masse from seasonal or glacial floating ice or by subaquatic sediment gravity flow from floating ice or local moraines.
Mise en évidence d'importantes variations régionales du flux de chaleur en Algérie
Authors: Takherist D. , Lesquer A.
Published: June 2009

Evaluation of heat flow in 230 oil wells, using temperature measurements (bottom-hole temperature and temperature of fluids in drill stem test) and various rock-porosity data, reveals a high heat-flow average (82 ± 19 mW∙m−2) associated with the Algerian Sahara basins.The isopleth map exhibits significant regional variations overprinted by short-wavelength anomalies that, in general, are related to the local geological structure.On a regional scale, we observe an essentially north–south zonation that is not directly related to the major structural units, except for the northern alpine domain. The southern area, at the border of the Hoggar Precambrian basement, is characterized by very high heat-flow values (90–130 mW∙m−2). The anomalies define a major axis, generally east–west, which seems to affect the northern part of the African plate, from the Canaries to Libya. Locally, some relationships with extensional Miocene–Pliocene–Quaternary volcanism suggest an association with recent mantle thermal events. [Journal Translation]
Palynostratigraphie et chronologie du retrait glaciaire au Témiscamingue: évaluation des âges 14C et implications paléoenvironnementales
Authors: Richard Pierre J. H. , Veillette Jean J. , Larouche Alayn C.
Published: June 2009

The 14C ages of the earliest organic deposits in 32 small lakes located higher than or near the altitudinal limit of proglacial Lake Barlow, in the Timiskaming region, span the period 10 400 – 6490 years BP. Identification of lags in organic accumulation by means of pollen and macrofossil assemblages allows the rejection of 14C dates later than 8500 BP as the minimum dates for local ice retreat in each lake basin. However, because of the absence of synchronous pollen zones, the pollen stratigraphy cannot be used to correlate the individual 32 sites and illustrate the geography of deglaciation between 10 400 and 8500 years BP. The directions of ice retreat are nevertheless apparent when the sites are grouped according to age, despite some geographical dispersion of sites with closely related 14C ages. The usefulness of pollen analysis in determining the age of deglaciation in the Timiskaming region is consequently nil, in contrast to the situation in northwest Europe. This unexpected characteristic is attributed to the peculiar palaeoenvironmental context of the proglacial Lake Barlow episode. At the scale of the Great Lakes – St. Lawrence River watershed, the differences in the pollen stratigraphies at the transition between the Pleistocene and the Holocene sediments and in the lower Holocene sediments appear to be the result of contrasting palaeoclimatic conditions existing in front of the ice sheet on both sides of Longitude 76°W, approximately.
Provenance of post-Wapiabi sandstones and its implications for Campanian to Paleocene tectonic history of the southern Canadian Cordillera
Authors: Mack Greg H. , Jerzykiewicz T.
Published: June 2009

Late Campanian to Early Paleocene sandstones of the Alberta Foothills were derived from three types of rocks: (i) andesitic–dacitic volcanic rocks that were presumably comagmatic with middle to late Mesozoic plutons in the Omineca Crystalline Belt; (ii) low-grade metamorphic rocks in the suprastructure of the Omineca Crystalline Belt; and (iii) sedimentary rocks in die Rocky Mountain Thrust Belt, principally pelitic rocks in the western Main Ranges and carbonates and chert-arenites in the eastern Main and Front ranges. A paucity of quartzo-feldspathic rocks fragments and potassium feldspar indicates that the core of the Omineca Crystalline Belt was not extensively exposed at that time.Vertical trends in composition of the sandstones reveal five petrographic stages. Stage I is dominated by volcanic rock fragments and plagioclase, suggesting that initial progradation of the sediment was largely a response to coeval volcanism or tectonic emplacement of older volcanic rocks. Stages III and V are characterized by a significant decrease in the relative proportion of metamorphic detritus and an increase in the proportion of carbonate and chert detritus. These stages may represent periods of thrusting in the eastern Main Ranges or Front Ranges. In contrast, stages II and IV display increases in metamorphic detritus and stage II shows a concomitant decrease in carbonate and chert detritus, trends that indicate wearing down of the eastern Main Ranges or Front Ranges thrust sheet(s) and reintegration of the Omineca Crystalline belt and the western Main Ranges into the drainage basin. The compositional stages indicative of thrust events are associated with coarse facies, including the Entrance and High Divide Ridge conglomerates, whereas those stages indicative of tectonic quiescence are associated with fine-grained facies including coal.
Assimilation and crystallization in basic magma chambers: trace-element and Nd-isotopic variations in the Kerns sill, Nipissing diabase province, Ontario
Authors: Lightfoot Peter C. , Naldrett Anthony J.
Published: June 2009

An investigation has been made of the trace-element and Nd-isotopic effects of assimilation at the roof of the Proterozoic Kerns sill in the 2.2 Ga Nipissing diabase province in Ontario. The ratios Th/Zr, La/Zr, and U/Zr and the concentrations of incompatible elements all tend to increase with decreasing Mg#, Ni, and Cr. These variations have been simulated by computer models in which assimilation and fractionation are coupled (AFC) and the most fractionated magmas (identified by low Mg#, Ni, and Cr and by high incompatible-element concentrations) are also the most contaminated (indicated by higher Th/Zr, La/Zr, and U/Zr and lower 143Nd/144Ndo). The results suggest that the ratio (r) of the change of magma mass due to assimilation relative to the change due to fractionation gradually increased. The latent heat of crystallization may have contributed sufficient heat to melt the roof of the intrusion where ponded crustal melts were separated from the underlying basic magma by a double-diffusive interface. Field relations suggest that this interface was progressively destroyed by convective erosion; thus the degree of contamination increased as the magma became more fractionated. These results are consistent with laboratory investigations designed to simulate assimilation at the roof of basaltic magma chambers.
Petrology of garnet–clinopyroxene amphibolites from Mont Albert, Gaspé, Quebec
Authors: O'Beirne-Ryan A. M. , Jamieson R. A. , Gagnon Y. D.
Published: June 2009

The Mont Albert mafic–ultramafic complex of central Gaspé, Quebec, is generally regarded as a partial ophiolite with an underlying metamorphic sole. The metamorphic rocks include a number of mineralogical and textural varieties of amphibolite, including some migmatite, as well as minor metasedimentary and quartzo-feldspathic gneisses. The most intriguing rocks in the complex are mafic to ultramafic garnet- and clinopyroxene-bearing amphibolites that are restricted to the vicinity of the peridotite contact. These rocks have unusual Fe-rich, Si-poor bulk compositions and may represent tholeiites chemically modified by interaction with fluid or melt before or during metamorphism. These amphibolites are not retrograde eclogites, since andesine was present throughout the metamorphic history, and the clinopyroxene is not omphacitic. Coexisting mineral compositions and temperature estimates overlap for core, rim, and matrix grains of all the major phases in the garnet–clinopyroxene amphibolites, implying equilibration in the range 750–800 °C at 8–9 kbar (1 kbar = 100 MPa). Garnet amphibolites lacking clinopyroxene yielded somewhat lower P–T estimates of 600–700 °C and 6–7 kbar. Owing to complex field relationships, it is not clear whether or not these P–T conditions resulted from evolution along a single P–T–t path.
U–Pb geochronologic constraints on the volcanic evolution of the Mira (Avalon) terrane, southeastern Cape Breton Island, Nova Scotia
Authors: Bevier Mary Lou , Barr Sandra M. , White Chris E. , Macdonald Alan S.
Published: June 2009

New U–Pb ages for late Precambrian volcanic and associated plutonic units in the Mira (Avalon) terrane of southeastern Cape Breton Island indicate that volcanic suites were erupted over a span of at least 100 Ma. The oldest dated rock is a quartz–feldspar rhyodacitic porphyry from the unit that hosts the Mindamar Zn–Pb–Cu–Ag–Au deposit in the Stirling belt, which has an age of [Formula: see text]. The most widespread volcanism and plutonism occurred at ca. 620 Ma in the East Bay Hills and Coxheath Hills belts, and probably the Sporting Mountain belt, as indicated by U–Pb ages and U–Pb maximum ages for rhyolite flows and U–Pb and Ar–Ar ages of crosscutting plutons, as well as stratigraphic constraints. Younger volcanic rocks occur in the Coastal belt, from which a rhyodacitic crystal tuff is dated at [Formula: see text] and a pluton is dated at 574 ± 3 Ma. A rhyolite flow from the contiguous Main-à-Dieu sequence yields a maximum age of ca. 563 Ma, and a minimum age for this sequence is indicated by overlying latest Precambrian to Cambrian fossiliferous sedimentary rocks. Middle Devonian plutonism in the Mira terrane is confirmed by an age of [Formula: see text] from the Lower St. Esprit granodiorite in the Coastal belt. The range of ages of volcanic and plutonic rocks in Mira terrane is similar to that in other parts of Avalon terrane in eastern Newfoundland and southern New Brunswick. Many of the dated rocks contain xenocrystic zircons of Middle Proterozoic ages which suggest a South American source.
U–Pb geochronology of the eastern Abitibi Subprovince. Part 1: Chibougamau–Matagami–Joutel region
Authors: Mortensen J. K.
Published: June 2009

U–Pb zircon, titanite, and baddeleyite ages are reported for 20 volcanic and plutonic rock units in the Chibougamau, Matagami, and Joutel areas of the northern Abitibi belt. Pretectonic magmatism occurred in three main pulses. Volcanic rocks of the Obatagamau Formation in the Chibougamau area were erupted at 2759 Ma. Following a possible hiatus in igneous activity, volcanism, accompanied by the emplacement of layered mafic intrusions, occurred in the Chibougamau, Matagami and Joutel areas in the period of 2730–2722 Ma. In the Chibougamau area, a slightly younger period of plutonism between 2720 and 2712 Ma is thought to be comagmatic with felsic volcanic rocks in the uppermost part of the Roy Group. Syntectonic intrusive rocks in the northern Abitibi belt range in age from 2701 to 2693 Ma. These ages are broadly comparable to ages obtained for syntectonic plutons elsewhere in the Abitibi belt, suggesting that tectonism associated with the Kenoran orogeny occurred at approximately the same time throughout the belt.
Sediment- and basalt-hosted regoliths in the Huronian supergroup: role of parent lithology in middle Precambrian weathering profiles
Authors: Sutton S. J. , Maynard J. B.
Published: June 2009

Weathering profiles developed side-by-side on sandstone and a mafic dike provide an unusual opportunity to examine the role of parent rock bulk composition in the chemical evolution of middle Precambrian regoliths. Because the profiles are adjacent to one another, differences in topography can be eliminated in accounting for differences in the chemical evolution of the two profiles. Both profiles show upward increases in Al, Ti, K, and Rb and decreases in Mg, Ca, and Na. In addition, the mafic regolith increases upward in Zr and Nb and decreases in Zn and Ni. Total Fe decreases upward in both profiles, but the sandstone profile retains significantly more of its initial Fe than does the mafic dike. This difference in Fe loss is consistent with weathering in a low-oxygen atmosphere of rock types with very different initial Fe contents and therefore different atmospheric requirements for complete oxidation of the Fe present. The Fe in the sandstone was mostly oxidized and retained within the profile, whereas much of the Fe in the mafic dike was not oxidized and was removed from the profile in the more soluble ferrous state. Petrographic evidence indicates that both sandstone and mafic dike weathering profiles underwent preweathering diagenesis, postweathering K–Rb metasomatism, and very low-grade metamorphism. Mineral chemistry indicates that, in the absence of chlorite, white mica composition closely reflects variation in bulk composition. Where both white mica and chlorite are present, changes in bulk composition are accommodated by variations in the proportions of these two minerals rather than by variations in white mica composition.
Role of rheological heterogeneities in vein-ore localization
Authors: Castaing C. , Cassard D. , Gros Y. , Moisy M. , Chabod J. C.
Published: June 2009

Structural studies of the Saint-Salvy zinc deposit and other Hercynian, veinhosted ore deposits in the French Massif Central and Pyrénées reveal a fourstage evolution of mineralized structures under rheological control: (i) localization of potential mineralized areas, guided by the presence of first-order lithological or structural heterogeneities that caused stress and strain perturbations; (ii) creation of second-order heterogeneities, corresponding to indurated shear zones that acted as rheological discontinuities; (iii) tectonic activation of these second-order heterogeneities, opening voids that allowed circulation of hydrothermal fluids and periodic trapping of ore minerals; (iv) reworking and partial destruction of the mineralized structures, caused by the reactivation of anisotropic surfaces acting as zones of weakness. The interaction between preexisting, first-order heterogeneities and regional shear strain caused instability, which in turn produced second-order and then lower-order heterogeneities. Such progressively smaller heterogeneities induced an increasingly focused, centripetal localization of structural disturbances that enabled hydrothermal fluid channelling. This is the reason that lower-order and late structures preferentially bear economic mineralization.
Genetic variation in carbon isotope discrimination and its relationship to growth under field conditions in full-sib families of Piceamariana
Authors: Flanagan Lawrence B. , Johnsen Kurt H.
Published: June 2009

Measurements of the stable carbon isotope composition of leaf tissue were made on Piceamariana (Mill.) B.S.P trees from four full-sib families grown on three different field sites at the Petawawa National Forestry Institute, Ontario, Canada. The four families chosen exhibited genetic variation for growth characteristics. Genetic variation was also observed for carbon isotopic discrimination (Δ) among the families of P. mariana. In addition, a strong correlation occurred between Δ values measured on trees in 1991 and 1992, two years that had very different precipitation and temperature conditions during the growing season, indicating that the ranking of individual trees remained almost constant between years. A strong, negative correlation was observed between average carbon isotope discrimination and average tree height for the four families on the driest, least productive site, as was expected based on leaf photosynthetic characteristics. There was no significant correlation, however, between Δ values and growth on the other two study sites, where productivity was higher.
Influence of forest age on nutrient availability and storage in coniferous soils of the Oregon Coast Range
Authors: Entry James A. , Emmingham William H.
Published: June 2009

A substantial fraction of the organic matter and plant essential nutrients in forest ecosystems are contained in the soil. The role of soils in nutrient storage and availability is an essential component of ecosystem function and stability. The top 10 cm of soil contains the highest concentration of nutrients. To determine the influence of forest age on nutrient storage and availability in riparian soils, we compared concentrations, storage, and extractability of plant nutrients in the litter layer and top 10 cm of mineral soil in old-, second-, and young-growth riparian forests. The analysis of variance for nutrient concentration, nutrient storage, or nutrients extracted in both the litter layer and top 10 cm of mineral soil showed no significant differences among sites or seasons for any nutrient; only differences among forest ages will be discussed. Concentrations of N, P, Mg, Mn, and Cu in forest litter did not differ by forest age, but concentrations of K, Ca, and B were significantly higher in old-growth forest litter than in the litter of second-or young-growth forests. In mineral soil, the concentrations of all nutrients were statistically equal for all forest ages. Old-growth forests stored significantly (P ≤ 0.05) greater amounts of all nutrients measured in the litter layer, and greater amounts of N, P, and K in the mineral soil, than were stored in second- or young-growth forests. Greater amounts of P, B, and Zn were extracted from old-growth forest litter than from either second- or young-growth forest litter, and greater amounts of P, K, Mn, B, and Zn were extracted from old-growth mineral soil than from second- or young-growth mineral soil. The amount of each nutrient stored in the litter layer of the different-aged forests correlated curvilinearly with the amount of C in the litter layer of these forests; r2 ranged from 0.60 to 0.83. Also, the amount of N, K, and Ca stored in the mineral soil correlated curvilinearly with the amount of C in the soil; r2 ranged from 0.50 to 0.76.
Identification de descripteurs morphométriques sensibles aux conditions générales de croissance des semis de chêne rouge [Quercusrubra) en milieu naturel
Authors: Trencia J.
Published: June 2009

Red oak (Quertusrubra L.) seedlings measuring less than 1 m in height were collected from seven sites in the Québec City region. The sites were grouped according to pedology, dendrometry, and phytosociology. The object of this study was to select morphometric characteristics that are most sensitive to global differences in growth conditions. Most of the variables studied are frequently used to assess seedling performance in greenhouse or laboratory experiments. The characteristics measured included total stem height; mean annual increment of the biomass; number, mass, and length of the roots; shoot/root dry mass ratio; specific root length. Two topologic variables were also measured: the total external pathlength and the diameter of the root system, as defined by Fitter. The topologic variables and number of roots differentiated well the various groups of sites. Among the variables chosen, it is possible to estimate the value of the ones that are most difficult to assess, from less time-consuming variables.
Patterns of foliar injury to red spruce on Whiteface Mountain, New York, during a high-injury winter
Authors: Boyce Richard L.
Published: June 2009

Winter injury to red spruce (Picearubens Sarg.) after the winter of 1992–1993 was measured at an elevation of 1050 m at a site on Whiteface Mountain in the Adirondack Mountains of New York. Approximately 21% of the 1992 foliage was injured. Damage increased with height in the canopy (P < 0.0001), and was highest on the southern aspect (P < 0.0001), followed by the western aspect, which sustained more damage than the northern and eastern aspects (P < 0.0001). Damage was highest on trees whose canopy was fertilized with nitrogen, intermediate on ground-fertilized trees, and lowest on untreated trees, but differences were not significant (P = 0.45) and were confounded with stand structure differences. The strong aspect and height patterns of damage confirm earlier work showing that solar radiation plays an important role in causing the freezing injury that leads to winter damage in red spruce.
Use of voltage clamp fluorimetry in understanding potassium channel gating: a review of Shaker fluorescence data
Authors: Horne A.J. , Fedida D.
Published: June 2009

Voltage clamp fluorimetry (VCF) utilizes fluorescent probes that covalently bind to cysteine residues introduced into proteins and emit light as a function of their environment. Measurement of this emitted light during membrane depolarization reveals changes in the emission level as the environment of the labelled residue changes. This allows for the correlation of channel gating events with movement of specific protein moieties, at nanosecond time resolution. Since the pioneering use of this technique to investigate Shaker potassium channel activation movements, VCF has become an invaluable technique used to understand ion channel gating. This review summarizes the theory and some of the data on the application of the VCF technique. Although its usage has expanded beyond voltage-gated potassium channels and VCF is now used in a number of other voltage- and ligand-gated channels, we will focus on studies conducted in Shaker potassium channels, and what they have told us about channel activation and inactivation gating.
Endoplasmic reticulum proteins in cardiac development and dysfunction
Authors: Prins Daniel , Michalak Marek
Published: June 2009

An understanding of cardiac pathologies and the molecular mechanisms thereof is essential for the development of therapies for cardiovascular disease, a common cause of death in Western societies. Investigations into heart diseases have shown that the endoplasmic reticulum and its diverse functions may lie at the center of many cardiac pathologies. Animal models have demonstrated that in numerous cases, faulty endoplasmic reticulum activity is manifested in defective cardiogenesis or impaired heart function. These findings suggest that the endoplasmic and sarcoplasmic reticulum membranes may represent functionally independent organelles responsible for specialized functions in the heart. This review addresses the molecular pathways linking endoplasmic reticulum function and malfunction with impaired cardiac phenotypes. The endoplasmic reticulum affects cardiac development and function through Ca2+-dependent pathways, its catalytic role in the proper folding and targeting of membrane-bound and secretory proteins, and its response to cellular stress events, particularly hypoxic conditions. These pathways present potential novel targets for treatment of cardiac disease.
Deep hypothermia impact on acid–base parameters and liver antioxidant status in an in vivo rat model
Authors: Alva Norma , Carbonell Teresa , Palomeque Jesús
Published: June 2009

Although clinical hypothermia is used for reducing postischemic damage, injurious effects have also been reported. To determine whether hypoxia and oxidative stress are induced by systemic deep hypothermia, we used an in vivo rat model keeping the arterial Pco2constant. Animals were divided into 4 groups: sham, 2 h deep hypothermia (21 °C), 1 h posthypothermia (rewarmed to 37 °C after 2 h deep hypothermia), and 3 h normothermia. Blood gases, portal vein blood flow, arterial pressure, and heart rate were monitored throughout the experiment. Liver enzyme antioxidant activity was also examined. The hemodynamic parameters decreased drastically during hypothermia, but were fully restored after rewarming. No changes in hepatic antioxidant activity (catalase, glutathione peroxidase, and superoxide dismutase) were observed. The redox level in liver (GSH/GSSG ratio) was preserved in hypothermia but decreased when animals were rewarmed. ALT did not increase and no evidence of tissue hypoxia was detected in liver regarding the restricted flow during hypothermia. With the described protocol, deep hypothermia is regarded as an experimental safe model.
Female territoriality in a paternal mouthbrooding cardinalfish to avoid predation against spawned eggs
Authors: Fukumori Kayoko , Okuda Noboru , Yanagisawa Yasunobu
Published: June 2009

Generally, paternal mouthbrooding cardinalfishes are characteristic of sex-role-reversed animals: females have a higher potential reproductive rate and are more active in mating competition than males, and the operational sex ratio (OSR) is female-biased. However, one species of cardinalfish, Apogon notatus (Houttuyn, 1782), shows unusual sex roles: females alone defend their breeding territories to form pairs, even though the OSR is male-biased. This is inconsistent with the general rule that breeding territoriality is shown by the more abundant sex. We examined the function of female breeding territory in this fish using field observations. Prior to the breeding season, large females established their territories earlier than small females. Earlier settlers occupied deeper areas with larger boulders where conspecifics were less likely to aggregate. As the level of conspecific aggregation increased, spawning females suffered from frequent intraspecific interference and subsequent egg predation, leading to increased time or energy spent on territorial defense. For the females, territories that have more boulders and fewer conspecifics might be of higher quality because such places are safe from egg predation and less costly to defend. We conclude that females defend their breeding territories to avoid predation of spawned eggs rather than to guard high-quality mates or to increase mating opportunities.
Growth and reproduction of female eastern and whitebelly spinner dolphins incidentally killed in the eastern tropical Pacific tuna purse-seine fishery
Authors: Larese Jason P. , Chivers Susan J.
Published: June 2009

Life-history parameters are estimated for two forms of the spinner dolphin ( Stenella longirostris (Gray, 1828)): the eastern subspecies ( Stenella longirostris orientalis Perrin, 1990) and the whitebelly hybrid. The data analyzed (n = 3138 eastern and 3099 whitebelly spinner dolphins) were collected between 1968 and 1994 from female dolphins incidentally killed in the yellowfin tuna ( Thunnus albacares (Bonnaterre, 1788)) purse-seine fishery that operates in the eastern tropical Pacific Ocean. Eastern spinner dolphins averaged 79.7 cm at birth, 121.5 cm at 1 year, and 171.5 cm at asymptotic length, and had a mean annual pregnancy rate of 0.351 and a calving interval of 2.84 years. Whitebelly spinner dolphins averaged 80.2 cm at birth, 122.5 cm at 1 year, and 177.1 cm at asymptotic length, and had a mean annual pregnancy rate of 0.329 and calving interval of 3.04 years. The mean age at attainment of sexual maturity was estimated to be 8.7 and 8.4 years for eastern and whitebelly spinner dolphins, respectively, which are 3.2 and 1.7 years older than those previously published. This difference indicates that the mean reproductive output during a female’s life is lower than previously expected and likely translates into lower population growth rates.
A HYBRID ADAPTIVE ALGORITHM FOR LINEAR OPTIMIZATION
Authors: SALAHI MAZIAR , TERLAKY TAMÁS
Published: June 2009

Recently, using the framework of self-regularity, Salahi in his Ph.D. thesis proposed an adaptive single step algorithm which takes advantage of the current iterate information to find an appropriate barrier parameter rather than using a fixed fraction of the current duality gap. However, his algorithm might do at most one bad step after each good step in order to keep the iterate in a certain neighborhood of the central path. In this paper, using the same framework, we propose a hybrid adaptive algorithm. Depending on the position of the current iterate, our new algorithm uses either the classical Newton search direction or a self-regular search direction. The larger the distance from the central path, the larger the barrier degree of the self-regular search direction is. Unlike the classical approach, here we control the iterates by guaranteeing certain reduction of the proximity measure. This itself leads to a one dimensional equation which determines the target barrier parameter at each iteration. This allows us to have a large update algorithm without any need for safeguard or special steps. Finally, we prove that our hybrid adaptive algorithm has an [Formula: see text] worst case iteration complexity.
SURFACE PLASMON RESONANCE SPECTROSCOPY AND QUARTZ CRYSTAL MICROBALANCE STUDY OF PROTEIN-DNA INTERACTIONS IN HORMONE RECEPTOR BIOLOGY
Authors: SU XIAODI
Published: June 2009

Surface plasmon resonance (SPR) spectroscopy and quartz crystal microbalance (QCM) are surface sensitive analytical techniques capable of real-time monitoring of biomolecular interactions. In this article we review our past work on the use of these two techniques for studying protein–DNA interactions, exemplified with estrogen receptors (ER) and their response elements (ERE). Various assay schemes have been developed for a comprehensive characterization of ER–ERE interactions in terms of sequence specificity, binding affinity, stoichiometry, ligand effects on binding dynamics and conformational changes in the proteins and DNA. These are all important characteristics underlining the mechanism of ER-mediated gene transcription. With these studies we have made the following demonstrations to describe the advantages of these two techniques, namely (i) SPR technique is superior and more versatile than conventional (electrophoretic mobility shift assay) EMSA for studying protein-DNA interactions; (ii) QCM is an alternative tool for studying conformational changes in protein–DNA complexes and (iii) combinational SPR and QCM analysis provides additional characterization of biomolecular films, e.g. film thickness, water content, and conformation rigidity etc.
HIGH MOBILITY CONJUGATED POLYMER SEMICONDUCTORS FOR ORGANIC THIN FILM TRANSISTORS
Authors: LI YUNING , ONG BENG S.
Published: June 2009

Organic thin film transistors (OTFTs) are promising candidates as alternatives to silicon TFTs for applications where light weight, large area and flexibility are required. OTFTs have shown potential for cost effective fabrication using solution deposition techniques under mild conditions. However, two major issues must be addressed prior to the commercialization of OTFT-based electronics: (i) low charge mobilities and (ii) insufficient air stability. This article reviews recent progress in the design and development of thiophene-based polymer semiconductors as channel materials for OTFTs. To date, both high performance p-type and n-type thiophene-based polymers with benchmark charge carrier mobility of > 0.5 cm2 V-1 s-1 have been archived, which bring printed OTFTs one step closer to commercialization.
RECENT DEVELOPMENTS IN THE MANUFACTURING OF COMPONENTS FROM ALUMINIUM-, MAGNESIUM- AND TITANIUM-BASED ALLOYS
Authors: JARFORS ANDERS E. W. , KAINER KARL-ULRICH , TAN MING-JEN , YONG JOHN
Published: June 2009

Recent developments in the field of manufacturing techniques and alloy development of light materials are reviewed. In the field of manufacturing Aluminium based components, special attention is given to casting, including liquid forging and semi-solid forming technology while for sheet metal forming technology the focus is on material properties and process technology in superplastic forming. For the manufacturing of Magnesium-based components, special attention is given to casting processes and alloy development for casting. For wrought Magnesium, material properties control is covered. For Titanium-based components, an overview of the latest additions to high strength alloys are given, including non-linear elasticity as demonstrated by materials like GUM Metal™. Advanced forming technology such as Levi Casting are also treated.
Mammalian Zinc Transporters: Nutritional and Physiologic Regulation
Authors: Lichten Louis A. , Cousins Robert J.
Published: June 2009

Research advances defining how zinc is transported into and out of cells and organelles have increased exponentially within the past five years. Research has progressed through application of molecular techniques including genomic analysis, cell transfection, RNA interference, kinetic analysis of ion transport, and application of cell and animal models including knockout mice. The knowledge base has increased for most of 10 members of the ZnT family and 14 members of the Zrt-, Irt-like protein (ZIP) family. Relative to the handling of dietary zinc is the involvement of ZnT1, ZIP4, and ZIP5 in intestinal zinc transport, involvement of ZIP10 and ZnT1 in renal zinc reabsorption, and the roles of ZIP5, ZnT2, and ZnT1 in pancreatic release of endogenous zinc. These events are major factors in regulation of zinc homeostasis. Other salient findings are the involvement of ZnT2 in lactation, ZIP14 in the hypozincemia of inflammation, ZIP6, ZIP7, and ZIP10 in metastatic breast cancer, and ZnT8 in insulin processing and as an autoantigen in diabetes.
Use of Phosphatide Precursors to Promote Synaptogenesis
Authors: Wurtman Richard J. , Cansev Mehmet , Sakamoto Toshimasa , Ulus Ismail H.
Published: June 2009

New brain synapses form when a postsynaptic structure, the dendritic spine, interacts with a presynaptic terminal. Brain synapses and dendritic spines, membrane-rich structures, are depleted in Alzheimer's disease, as are some circulating compounds needed for synthesizing phosphatides, the major constituents of synaptic membranes. Animals given three of these compounds, all nutrients—uridine, the omega-3 polyunsaturated fatty acid docosahexaenoic acid, and choline—develop increased levels of brain phosphatides and of proteins that are concentrated within synaptic membranes (e.g., PSD-95, synapsin-1), improved cognition, and enhanced neurotransmitter release. The nutrients work by increasing the substrate-saturation of low-affinity enzymes that synthesize the phosphatides. Moreover, uridine and its nucleotide metabolites activate brain P2Y receptors, which control neuronal differentiation and synaptic protein synthesis. A preparation containing these compounds is being tested for treating Alzheimer's disease.