bluuebunny/crossref_metadata_2025 huggingface dataset:
Potentiation of large conductance, Ca2+‐activated K+ (BK) channels by α5β1 integrin activation in arteriolar smooth muscle
Authors: Wu Xin , Yang Yan , Gui Peichun , Sohma Yoshiro , Meininger Gerald A. , Davis George E. , Braun Andrew P. , Davis Michael J.
Published: January 2008

Injury/degradation of the extracellular matrix (ECM) is associated with vascular wall remodelling and impaired reactivity, a process in which altered ECM–integrin interactions play key roles. Previously, we found that peptides containing the RGD integrin‐binding sequence produce sustained vasodilatation of rat skeletal muscle arterioles. Here, we tested the hypothesis that RGD ligands work through α5β1 integrin to modulate the activity of large conductance, Ca2+‐activated K+ (BK) channels in arteriolar smooth muscle. K+ currents were recorded in single arteriolar myocytes using whole‐cell and single‐channel patch clamp methods. Activation of α5β1 integrin by an appropriate, insoluble α5β1 antibody resulted in a 30–50% increase in the amplitude of iberiotoxin (IBTX)‐sensitive, whole‐cell K+ current. Current potentiation occurred 1–8 min after bead–antibody application to the cell surface. Similarly, the endogenous α5β1 integrin ligand fibronectin (FN) potentiated IBTX‐sensitive K+ current by 26%. Current potentiation was blocked by the c‐Src inhibitor PP2 but not by PP3 (0.1–1 μm). In cell‐attached patches, number of open channels × open probability (NPo) of a 230–250 pS K+ channel was significantly increased after FN application locally to the external surface of cell‐attached patches through the recording pipette. In excised, inside‐out patches, the same method of FN application led to large, significant increases in NPo and caused a leftward shift in the NPo–voltage relationship at constant [Ca2+]. PP2 (but not PP3) nearly abolished the effect of FN on channel activity, suggesting that signalling between the integrin and channel involved an increase in Ca2+sensitivity of the channel via a membrane‐delimited pathway. The effects of α5β1 integrin activation on both whole‐cell and single‐channel BK currents could be reproduced in HEK 293 cells expressing the BK channel α‐subunit. This is the first demonstration at the single‐channel level that integrin signalling can regulate an ion channel. Our results show that α5β1 integrin activation potentiates BK channel activity in vascular smooth muscle through both Ca2+‐ and c‐Src‐dependent mechanisms. This mechanism is likely to play a role in the arteriolar dilatation and impaired vascular reactivity associated with ECM degradation.
Complete Chemical Synthesis, Assembly, and Cloning of a
Mycoplasma genitalium
Genome
Authors: Gibson Daniel G. , Benders Gwynedd A. , Andrews-Pfannkoch Cynthia , Denisova Evgeniya A. , Baden-Tillson Holly , Zaveri Jayshree , Stockwell Timothy B. , Brownley Anushka , Thomas David W. , Algire Mikkel A. , Merryman Chuck , Young Lei , Noskov Vladimir N. , Glass John I. , Venter J. Craig , Hutchison Clyde A. , Smith Hamilton O.
Published: January 2008

We have synthesized a 582,970–base pair
Mycoplasma genitalium
genome. This synthetic genome, named
M. genitalium
JCVI-1.0, contains all the genes of wild-type
M. genitalium
G37 except MG408, which was disrupted by an antibiotic marker to block pathogenicity and to allow for selection. To identify the genome as synthetic, we inserted “watermarks” at intergenic sites known to tolerate transposon insertions. Overlapping “cassettes” of 5 to 7 kilobases (kb), assembled from chemically synthesized oligonucleotides, were joined by in vitro recombination to produce intermediate assemblies of approximately 24 kb, 72 kb (“1/8 genome”), and 144 kb (“1/4 genome”), which were all cloned as bacterial artificial chromosomes in
Escherichia coli
. Most of these intermediate clones were sequenced, and clones of all four 1/4 genomes with the correct sequence were identified. The complete synthetic genome was assembled by transformation-associated recombination cloning in the yeast
Saccharomyces cerevisiae
, then isolated and sequenced. A clone with the correct sequence was identified. The methods described here will be generally useful for constructing large DNA molecules from chemically synthesized pieces and also from combinations of natural and synthetic DNA segments.
Oestrogen receptors α and β show different associations to clinicopathological parameters and their co-expression might predict a better response to endocrine treatment in breast cancer
Authors: Borgquist S , Holm C , Stendahl M , Anagnostaki L , Landberg G , Jirström K
Published: January 2008

Aims:

The majority of all breast cancers are hormone responsive, traditionally defined by the expression of oestrogen receptor (ER) α and/or progesterone receptors. In contrast to ERα, the clinical significance of the relatively recently identified ERβ is still unclear. This study aimed to define the relationship between ERβ and clinicopathological parameters in a mixed cohort of breast cancer and, furthermore, to investigate the impact of ERβ expression on disease outcome.

Methods:

The immunohistochemical expression of ERα and ERβ was analysed in tissue microarrays containing a total number of 512 tumours with all incident breast cancers diagnosed at the Malmö University Hospital between 1988 and 1992.

Results:

78% of the tumours were ERα positive and 50% were ERβ positive. ERβ correlated positively with ERα (p = 0.001). In contrast to ERα, ERβ was not associated with any important clinicopathological variables. Furthermore, no overall prognostic significance could be demonstrated for ERβ. In the ERα-positive subgroup, however, a low expression of ERβ correlated with a decreased disease-free survival in patients receiving endocrine treatment (p = 0.003).

Conclusions:

Although interrelated, ERα and ERβ seem to be differentially associated to clinicopathological parameters, and this would support the fact that they might have different functions in vivo. Furthermore, ERβ might be a predictive marker of response to endocrine therapy, although this needs to be confirmed in additional studies, preferably randomised trials.
Infective endocarditis incidentally discovered by pathological examination: Figure 1
Authors: Lepidi H , Casalta J-P , Gouriet F , Collart F , Habib G , Raoult D
Published: January 2008

We present three patients in whom a cardiac valve replacement was needed because of degenerative and supposed non-infectious damage. The excised valves showed histological features of infective endocarditis with detection of micro-organisms. This diagnosis of infective endocarditis was confirmed by other diagnostic methods. Pathological examination of cardiac valves remains the gold standard for the diagnosis of infective endocarditis, and it should be routinely performed even without suspicion of infectious process.
Nucularcidae: a new family of palaeotaxodont Ordovician pelecypods (Mollusca) from North America and Australia
Authors: Pojeta Jr. John , Stott Christopher A
Published: January 2008

The new Ordovician palaeotaxodont family Nucularcidae and the new genus Nucularca are described. Included in Nucularca are four previously described species that have taxodont dentition: N. cingulata (Ulrich) (the type species), N. pectunculoides (Hall), N. lorrainensis (Foerste), and N. gorensis (Foerste). All four species are of Late Ordovician (Cincinnatian Katian) age and occur in eastern Canada and the northeastern USA. Ctenodonta borealis Foerste is regarded as a subjective synonym of Nucularca lorrainensis. No new species names are proposed. The Nucularcidae includes the genera Nucularca and Sthenodonta Pojeta and Gilbert-Tomlinson (1977). Sthenodonta occurs in central Australia in rocks of Middle Ordovician (Darriwilian) age. The 12 family group names previously proposed for Ordovician palaeotaxodonts having taxodont dentition are reviewed and evaluated in the Appendix.
Granulite-facies regional and contact metamorphism of the Tasiuyak paragneiss, northern Labrador: textural evolution and interpretation
Authors: Tettelaar Tanya , Indares Aphrodite
Published: January 2008

The Tasiuyak paragneiss at the western margin of the Nain Plutonic Suite has been subjected to two granulite-facies metamorphic events: (i) regional metamorphism during the Paleoproterozoic Torngat orogeny, and (ii) contact metamorphism due to emplacement of the Mesoproterozoic Nain Plutonic Suite. Regional metamorphism led to partial melting of pelitic rocks and the development of a locally well-preserved sequence of prograde and retrograde textures. These textures are partly controlled by bulk composition and formed in the pressure–temperature (P–T) field of the continuous reaction: biotite + sillimanite + plagioclase + quartz  = garnet + K-feldspar + melt, along a hairpin P–T path with peak conditions of ~8–10 kbar (0.8–1.0 GPa) and up to 870 °C in the NaKFMASH (Na2O–K2O–FeO–MgO–Al2O3–SiO2–H2O) system. These textures controlled the development of the contact metamorphic assemblages. Contact metamorphism of the pelitic rocks between the Tessiarsuyungoakh intrusion and the Makhavinekh Lake pluton led to growth of orthopyroxene-cordierite symplectite after garnet–biotite, and cordierite–spinel symplectite after garnet–sillimanite. These phase associations attest to reactions in specific microtextural settings, some of which produced a second generation of partial melt. Maximum temperatures were above ~750 °C and pressures were lower than those of the regional metamorphism. The aureole around the Makhavinekh Lake pluton is ~4 km wide and shows a progressive development of the contact metamorphic assemblages toward the pluton. In contrast, the contact metamorphic overprint is incipient around the Tessiarsuyungoakh intrusion, which developed a ~20 m wide contact aureole and is most prominent in screens of paragneiss within that intrusion.
McMurray Formation foraminifera within the lower Albian (Lower Cretaceous) Loon River shales of northern Alberta
Authors: Stelck C R , Trollope F H , Norris A W , Pemberton S G
Published: January 2008

Early Cretaceous paleogeography and biostratigraphy of western Canada are reviewed in light of a reassessment of foraminiferal and microfloral data from unpublished university theses on the early Albian Loon River shales of the lower Peace River area of northern Alberta (Norris 1951; Trollope 1951). The Loon River Formation, once considered to be an obsolete term, comprises numerous “zones” of foraminifera, radiolarian, and algal cysts, in ascending order Rectobolivina sp., lower Radiolarian zone, lower Leiosphaeridia zone, Haplophragmoides yukonensis, upper Radiolarian zone, upper Leiosphaeridia zone, Trochammina mcmurrayensis, Valvulineria loetterlei, Haplophragmoides topagorukensis, Marginulinopsis collinsi, and Haplophragmoides gigas minor. The upper part of the Loon River Formation, from the upper Radiolarian zone onwards, correlates with the McMurray, Wabiskaw, and Clearwater formations of the Fort McMurray area of northeastern Alberta. Molluscan data from various localities in western Canada indicates that the entire Loon River succession occurred within the early Albian. The presence of Inoceramus dowlingi and Cleoniceras sp. with the Marginulinopsis collinsi microfauna permits correlation of the type Clearwater Formation and type McMurray Formation with the Moosebar Formation of northeastern Bristish Columbia. An anomalous thick sequence of Leiosphaeridia (algal cysts) beds, bounded above and below by radiolarian-bearing strata, occurs in the mid part of the Loon River shales outcropping ~40 km along the lower Peace River. The Trochammina mcmurrayensis microfauna occurs 2–3 m below Inoceramus dowlingi and 30 m above Cleoniceras sp., and above the upper Leiosphaeridia zone. The radiolarian and Leiosphaeridia beds are considered to be the offshore neritic homotaxial equivalent of deltaic strata in the upper part of the McMurray Formation. The mid and lower Loon River shales are potential oil sources for the tar of the McMurray Formation, and this is supported by recent radiometric dating of the tar by Rhenium–Osmium isotopic analysis.
Cessation of ice-wedge development during the 20th century in spruce forests of eastern Mackenzie Delta, Northwest Territories, Canada
Authors: Kokelj S V , Pisaric M FJ , Burn C R
Published: January 2008

Ice wedges are presently inactive in white spruce (Picea glauca) forests of eastern Mackenzie Delta as shown by the absence of vein ice above ice wedges, the maintenance of intact breaking cables, and the abundance of rootlets propagating across ridge–trough sequences. At spruce forest sites, near-surface ground cooling rates and minimum near-surface temperatures from the years 2003–2005 were above ice-wedge cracking thresholds. Ground thermal conditions associated with cracking were recorded at a tundra peatland with active ice wedges. Annual mean permafrost temperatures at the spruce forest sites ranged from –1.8 to –2.9 °C, whereas at the tundra peatland, the permafrost was colder than –6 °C. Although winter air temperatures are similar throughout the study region, deeper snow cover, thicker active layers, and warmer permafrost account for the more gradual seasonal cooling and warmer near-surface temperatures recorded at the subarctic forest sites. The subtle ridge to trough relief, 12–35 cm of permafrost above wedge ice, roots up to 80 years old grown across ice wedges, and negligible tritium levels in wedge ice indicate that thermal contraction cracking in the spruce forests has been infrequent throughout much of the last century. The proximity of wedge ice to the base of the aggrading permafrost table and the absence of old spruce roots spanning ice-wedge troughs suggest that ice-wedge cracking did occur in the forest environments during the cold and dry conditions associated with the Little Ice Age and early part of the 20th century. When these ice wedges cracked, minimum temperatures at the top of permafrost were probably at least 3–8 °C colder than presently observed and similar to present conditions at the tundra peatland.
Late Holocene sea-level change around Newfoundland
Authors: Daly Julia F , Belknap Daniel F , Kelley Joseph T , Bell Trevor
Published: January 2008

Differential sea-level change in formerly glaciated areas is predicted owing to variability in extent and timing of glacial coverage. Newfoundland is situated close to the margin of the former Laurentide ice sheet, and the orientation of the shoreline affords the opportunity to investigate variable rates and magnitudes of sea-level change. Analysis of salt-marsh records at four sites around the island yields late Holocene sea-level trends. These trends indicate differential sea-level change in recent millennia. A north–south geographic trend reflects submergence in the south, very slow sea-level rise in the northeast, and a recent transition from falling to rising sea-level at the base of the Northern Peninsula. This variability is best explained as a continued isostatic response to deglaciation.
Geophysical modeling of Devonian plutons in the southern Gulf of St. Lawrence: implications for Appalachian terrane boundaries in Maritime Canada
Authors: Cook Lori A , Dehler Sonya A , Barr Sandra M
Published: January 2008

A prominent positive magnetic anomaly spans the 100 km distance between Prince Edward Island and Cape Breton Island in the southern Gulf of St. Lawrence. The anomaly occurs in an area of complex structure where Appalachian terrane boundaries are poorly resolved because of thick late Paleozoic sedimentary cover. Analysis of the magnetic anomaly led to the interpretation that it is produced by four separate, approximately circular, source bodies aligned along the northwesterly trend of the anomaly. Seismic data, physical property measurements, and magnetic and gravity anomalies were used to further investigate the anomaly sources through forward modeling techniques. The four source bodies have densities and magnetic susceptibilities compatible with dioritic to granitic compositions. Modeling also suggests that basement to the north of the plutons has higher density and susceptibility than basement to the south, and hence the source bodies are interpreted as plutons emplaced along the boundary between Ganderian composite terranes to the north and the Ganderian Brookville – Bras d’Or terrane to the south. This interpretation suggests that the Ganderia–Avalonia boundary is located farther south, and shows the need for re-evaluation of the location and role of the Canso fault in offsetting terranes between Cape Breton Island and southern New Brunswick.
Detrital zircon constraints on terrane ages and affinities and timing of orogenic events in the San Juan Islands and North Cascades, Washington
Authors: Brown Edwin H , Gehrels George E
Published: January 2008

Detrital zircon geochronology of this report pertains to Cretaceous orogeny in northwest Washington, an event that involved blueschist metamorphism and emplacement of nappes in the San Juan Islands – northwest Cascades thrust system and continental arc magmatism and associated Barrovian metamorphism in the neighboring Coast Plutonic Complex. Structurally low in the thrust system, quartzose gneiss of the Yellow Aster Complex yields an entirely Precambrian suite of detrital zircons, with an age pattern that is similar to that of Ordovician miogeoclinal rocks and the outboard Yukon–Tanana, Yreka, and Shoo Fly terranes elsewhere in the Cordillera. Midway in the nappe pile of the northwest Cascades, sandstone in the Bell Pass Mélange has a zircon age population of 110 Ma, an age that together with the spectrum of exotic materials associated with the sandstone suggests the mélange was a major zone of dislocation during mid-Cretaceous nappe emplacement. At a high level in the thrust system are nappes of the Fidalgo Complex, Lummi Formation, Constitution Formation, and Easton Metamorphic Suite, all with a prominent age peak in the range of 148–155 Ma. These units appear to be mutually related, represent inter-arc marginal basins, and are correlative with terranes in the western Klamath Mountains. The Nooksack Formation, footwall to nappes in the Cascades, has a zircon population at 114 Ma, providing a maximum age of nappe emplacement. The Tonga Formation of the Coast Plutonic Complex bears zircons that indicate a depositional age of <125 Ma, thus yielding a maximum age for the beginning of Barrovian metamorphism and continental arc plutonism in this region.
A Late Triassic flora from east-central Axel Heiberg Island, Nunavut, Canada
Authors: Vavrek Matthew J , Larsson Hans C.E. , Rybczynski Natalia
Published: January 2008

A new floral assemblage is described from the Fosheim Member of the Heiberg Formation on southern Axel Heiberg Island. The flora is relatively diverse, consisting of at least 10 different collected species and three field-identified species from a single small locality. The flora has some similarities to other European–Sinian floras, such as those previously found on Axel Heiberg and Ellesmere islands and in Scoresby Sound of eastern Greenland. The largest difference from previously described floras is the dominance of the bennettitalean Pterophyllum astartense, suggesting a drier climate in contrast to the more humid one previously proposed. The presence of Lepidopteris ottonis places the flora within the Upper Triassic Lepidopteris zone, suggesting a Norian age.
Paleomagnetic and mineral magnetic constraints on Zn–Pb ore genesis in the Pend Oreille Mine, Metaline district, Washington, USA
Authors: Pannalal S Johari , Symons David TA , Leach David L
Published: January 2008

Zinc–lead mineralization in the Metaline mining district of northeastern Washington, USA, is hosted by the Cambrian Metaline Formation and is classified into Yellowhead-type (YO) and Josephine-type (JO) ore based on texture and mineralogy. Paleomagnetic results are reported for four Cambrian Metaline Formation sites, one Ordovician Ledbetter slate site, 12 YO and 13 JO (including two breccia sites) mineralization sites in the Pend Oreille Mine, and eight sites from the nearby Cretaceous Kaniksu granite batholith. Thermal and alternating field step demagnetization, saturation isothermal remanence analysis, and synthetic specimen tests show that the remanence in the host carbonates and Zn–Pb mineralization is carried mostly by pseudosingle (PSD) to single domain (SD) pyrrhotite and mostly by PSD to SD magnetite in the Kaniksu granite. Based on thermomagnetic measurements, sphalerite and galena concentrates and tailings from the mine’s mill contain hexagonal and monoclinic pyrrhotite. The postfolding characteristic remanent magnetization (ChRM), known thermal data, and paleoarc method of dating suggest that the Zn–Pb mineralization carries a primary chemical remanent magnetization (CRM), and Metaline Formation carbonates a secondary CRM that were acquired during the Middle Jurassic (166 ± 6 Ma) during the waning stages of the Nevadan orogeny. A paleomagnetic breccia test favours a solution-collapse origin for the Josephine breccia. Finally, the Kaniksu paleopole is concordant with the North American Cretaceous reference paleopole, suggesting the Kootenay terrane has not been rotated since emplacement of the batholith at ~94 Ma.
Late Holocene glacial activity of Bridge Glacier, British Columbia Coast Mountains
Authors: Allen Sandra M , Smith Dan J
Published: January 2008

Bridge Glacier is a prominent eastward-flowing valley glacier located on the east side of the Pacific Ranges within the southern British Columbia Coast Mountains. The terminus of Bridge Glacier has retreated at rates up to 125 m/year over the last 50 years and currently calves into proglacial Bridge Lake. Field investigations of the recently deglaciated terrain and moraines led to the discovery of detrital boles and glacially sheared stumps. Dendroglaciological analyses of this subfossil wood produced five radiocarbon-controlled floating tree-ring chronologies. The relative age and stratigraphic location of these samples revealed that Bridge Glacier experienced at least four periods of significant advance during the late Holocene: a Tiedemann-aged advance ca. 3000 14C years BP, an unattributed advance ca. 1900 14C years BP, a first millennium advance ca. 1500 14C years BP, and a Little Ice Age advance beginning ca. 700 14C years BP. Lichenometric investigations at eight terminal and lateral moraine complexes identified early Little Ice Age moraine stabilization during the late 13th to early 14th centuries, with subsequent ice-front oscillations ending in the middle 15th, early 16th, middle to late 17th, early 18th, middle to late 19th, and early 20th centuries. These investigations build upon previous research and compliment recent geobotanical evidence emerging from other glaciers in this region that describe multiple late Holocene glacier advances. The discovery of a glacially sheared whitebark pine stump dating to 1500 ± 50 14C years BP provides irrevocable proof for an advance of Bridge Glacier during a time when glaciers throughout Pacific North America were also expanding.
Influence of degree of saturation on soil nail pull-out resistance in compacted completely decomposed granite fill
Authors: Su Li-Jun , Chan Terence C.F. , Shiu Y.K. , Cheung Tony , Yin Jian-Hua
Published: January 2008

The nail–soil interface shear strength is a key parameter in the design and stability assessment of soil nailing systems. A number of factors will influence the nail–soil interface shear strength. Among these factors, the degree of saturation (Sr) of the soil is an important one especially for permanent soil nail structures. To study the influence of Sron soil nail pull-out shear resistance, a series of laboratory pull-out tests have been conducted on soil nails in compacted completely decomposed granite (CDG) fill prepared to different Sr. The tests were conducted using two specially designed pull-out boxes (with same specifications). In the near-saturated tests, a high Sr(about 98%) was achieved using two special features of the apparatus: a waterproof front cap and back-water pressure pipes at the bottom of the pull-out box. Test results showed that the nail–soil shearing plane migrated outwards into the soil when the Srof the soil increased. Also, peak pull-out strengths of soil nails were strongly influenced by the Srof the soil. Among the tested Sr, the highest values of peak pull-out shear strength were obtained at Srvalues between 50% and 75%.
Modelling the clogging of coarse gravel and tire shreds in column tests
Authors: Rowe R. Kerry , Babcock Dan
Published: January 2008

A combination of data from laboratory tests and modelling is reported for both coarse gravel (19–38 mm) and two types of tire shred permeated with municipal solid waste leachate. It is suggested that the dispersivity of both the coarse gravel (initially about 4 mm) and tire shreds (initially about 45 mm) increases as the porosity of the drainage media is reduced because of clogging. The detachment of biofilm caused by growth and shear is examined and both are found to influence clogging. The average grain size estimated based on the measured surface area of the particles within a unit volume is shown to provide a good prediction of the rate of clogging for gravel and a conservative prediction for tire shreds. The size and density of suspended solids in leachate is found to significantly influence clogging rates. It is shown that Monod kinetic constants deduced for gravel at 27 °C give a good prediction of clogging for two different types of tire shred at the same temperature. Calibrated parameters used with the BioClog model are shown to give good fits to the porosity of both gravel and tire shred drainage material in laboratory column tests over time periods of up to 2 years.
Liquefaction assessment by the unit energy concept through centrifuge and torsional shear tests
Authors: Dief Hesham M. , Figueroa J. Ludwig
Published: January 2008

The fundamentals of the energy concept to assess the liquefaction potential of cohesionless soils have been formulated in recent years. To examine the validity of this procedure, a series of centrifuge liquefaction tests were carried out using the same soils that were tested previously as part of extensive research conducted on the subject at Case Western Reserve University. A total of 30 liquefaction tests at accelerations of 50g and 60g  were conducted on scaled pore fluid saturated models, prepared in a laminar box, representing a prototype soil deposit. The influence of relative density and effective confining pressure, as well as the effect of different grain size distribution on the energy per unit volume required for liquefaction, is studied. Generalized relationships were obtained by performing regression analyses between the energy per unit volume at the onset of liquefaction and liquefaction affecting parameters. These equations are compared with similar ones that were developed previously using torsional shear tests. A rational procedure to determine site response to earthquake loading and liquefaction susceptibility of a soil deposit is verified.
Reliability approach for the side resistance of piles by means of the total stress analysis (α Method)
Authors: Cherubini C. , Vessia G.
Published: January 2008

The evaluation of the pile–soil adhesion plays a fundamental role in the estimation of the side resistance for total stress analysis. Over the years, researchers have presented proposals for adhesion factor formulations even though only a few of them have shown a certain agreement in numerical and (or) methodological terms. Hence, several real-size experimental analyses have improved the understanding of the pile–soil adhesion phenomenon and mechanism. Nevertheless, the undrained shear strength (cu) values depend on the experimental technique employed. Such results force engineers to make a difficult choice among various formulations. A reliability analysis is performed in this paper to take into consideration the variations in formulations and values of the side resistance of bored piles in clayey soils. This study involves piles having different lengths and diameters, which are supposed to be bored in Matera clays. Such soil is characterized by means of laboratory investigation campaign, and its mechanical and stochastic main features are reported here. Values of reliability index β are calculated by means of the first-order reliability method.
The Canadian forest product sector: a sectoral econometric model
Authors: Kant Shashi , Nautiyal J.C. , Ai-Ameen Wafa
Published: January 2008

A sectoral model of the forest product sector (FPS) comprising the wood, furniture, and pulp and paper industries has been developed and estimated from 31 (1961–1991) years of data. The model consists of seven behavioral equations ((i) total output, (ii) domestic consumption, (iii) exports, (iv) imports, and prices of (v) consumption, (vi) exports, and (vii) imports) and one identity for each industry. Four additional identities complete the structure of the entire FPS model. The performance of this model is evaluated by sample period simulation. A forecast has been made for the next 5 years, and impact analysis has been done for changes in housing activity. The forecast indicates a slower annual growth in the FPS than in the total economy.
Effects of light on growth, crown architecture, and specific leaf area for naturally established Pinuscontorta var. latifolia and Pseudotsugamenziesii var. glauca saplings
Authors: Chen Han Y.H. , Klinka Karel , Kayahara Gordon J.
Published: January 2008

We studied growth, crown architecture, and specific leaf area acclimation of a shade-intolerant species, Pinuscontorta Dougl. ex Loud. var. latifolia Engelm., and a moderately shade-tolerant species, Pseudotsugamenziesii var. glauca (Beissn.) Franco, using naturally regenerated saplings along a wide range of light conditions. Study sites were located within a dry-summer, cool-temperate climate represented by the Dry Cool Interior Douglas-fir biogeoclimatic subzone near Williams Lake, British Columbia, Canada. In an open light environment, Pinuscontorta had a greater growth increment in both terminal and lateral shoots than did Pseudotsugamenziesii. With decreasing light availability (i) terminal increment, mean lateral increment, and total lateral increment decreased in both species (although Pinuscontorta reduced lateral growth significantly faster than Pseudotsugamenziesii); (ii) the ratio of mean lateral to terminal increment in Pinuscontorta did not change, but significantly increased in Pseudotsugamenziesii; (iii) the ratio of total lateral to terminal increment in Pinuscontorta decreased, but increased in Pseudotsugamenziesii; and (iv) specific leaf area in both species increased (in Pseudotsugamenziesii, it was always higher and increased marginally faster than in Pinuscontorta). We concluded that the less shade-tolerant Pinuscontorta was less plastic in crown architecture and specific leaf area than the more shade-tolerant Pseudotsugamenziesii.
Reducing Phellinusweirii inoculum by applying fumigants to living Douglas-fir
Authors: Thies Walter G. , Nelson Earl E.
Published: January 2008

In 1982, Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) trees were placed in three disease classes based on signs and symptoms of laminated root rot caused by Phellinusweirii (Murr.) Gilb. Eight fumigation treatments and an untreated check were applied to five replicate trees within each disease class. The dose applied to each tree was based on the estimated biomass in the belowground portion of the bole, large roots, and first 2.4 m of the aboveground bole. The highest dosages tested were 1.5 g of methylisothiocyanate (MITC), 6.7 mL of chloropicrin (trichloronitromethane), and 6.7 mL of Vorlex (v/v 20% MITC, 80% chlorinated C3 hydrocarbons)/kg biomass. In 1991 the roots of all surviving trees were excavated (roots of other trees were excavated at time of death), dissected, and sampled for viable Phellinusweirii. Twenty-four of the 30 trees treated with the two highest dosages of chloropicrin were killed, presumably by the fumigant. None of 45 trees treated with MITC and only 3 of 15 trees treated with Vorlex died, as did 3 of 15 untreated check trees. Volume of stained and decayed roots occupied by viable Phellinusweirii was reduced 78–90% by MITC or Vorlex compared with reductions of 51–65% by chloropicrin at the two lower, less phytotoxic doses, and 9% for untreated checks.
Season and intensity of water stress effects on needle toughness of ponderosa pine
Authors: McMillin Joel D. , Wagner Michael R.
Published: January 2008

The response patterns of needle toughness (a host plant trait correlated with resistance to pine sawflies (Hymenoptera: Diprionidae)) were investigated under greenhouse conditions at varying levels of water stress during different periods in the annual growth cycle of ponderosa pine (Pinusponderosa Dougl. ex Laws.) seedlings. We performed a 2 (stress level) × 4 (genotype) factorial design (study 1), and a 2 (season of stress) ×3 (stress level) × 6 (genotype) factorial design (study 2) to examine the influence of water stress on needle toughness. Moderate levels of water stress in study 1 produced seedlings with tougher needles than the low-stress conditions. Seedlings subjected to high levels of water stress during the shoot-growth period had the highest needle toughness among all treatments in study 2. In addition, significant differences in needle toughness among open-pollinated families in both studies suggest that needle toughness varies from tree to tree and may in part be genetically regulated. We also found a significant linear relationship between root/shoot ratio and needle toughness and an inverse relationship between needle toughness and total seedling biomass in study 1. These findings support in general a previously published growth–differentiation balance concept and may also represent possible adaptations of ponderosa pine to herbivory and the relatively xeric environment of the southwestern United States.
A biophysical soil–site model for estimating potential productivity of forested landscapes
Authors: Milner K.S. , Running S.W. , Coble D.W.
Published: January 2008

A biophysical soil–site model is presented for predicting potential forest productivity, defined as cubic metres per hectare per year at culmination of mean annual increment (CMAI), for use in forest taxation by the state of Montana. The model combines soil, climate, and topographic data layers within a geographic information system; a climate model (MT-CLIM); and an ecosystem carbon–water balance model (Forest-BGC) to generate estimates of potential forest productivity for all forested sites in the state. Weather station data were used to define base climate regions within the state, and to build regional precipitation models. Hydrologic equilibrium theory was used to estimate maximum leaf area from climate and soil water availability. Forest-BGC was initialized with estimates of the stem, leaf, and root carbon pools (kg C/ha) at CMAI and the 1-year prediction of stem carbon increment (kg C•ha−1•year−1) was taken as the initial estimate of potential productivity. The gross stem carbon increment was then converted to wood increment, reduced for branch wood growth, and finally adjusted for mortality rates found in regional yield tables. Other model adjustments included stockability factors for low-elevation forest–grassland sites, and modification of a photosynthesis rate parameter for north aspects. Response surfaces show potential productivity to vary as expected with precipitation, soil water, and temperature. Despite rather gross resolution of model inputs, regressions of site index on model predictions showed R2 values and standard errors comparable with those found when fitting empirical soil–site equations in the region.
Effect of prechilling on the dormancy of Betulapendula seeds
Authors: Vanhatalo Veikko , Leinonen Kari , Rita Hannu , Nygren Markku
Published: January 2008

The effect of prechilling on the germination response to temperature was investigated by germinating prechilled (at 5 °C) and unchilled seeds of Betulapendula Roth (silver birch) at temperatures of 10, 15, 20, 25, and 30 °C in darkness. Unchilled and prechilled seeds produced 50% germination at temperatures of 26.7 and 15.3 °C, respectively. Two experiments were organized to study the effects of a range of prechilling temperatures (0–12 °C) on release of dormancy. The level of dormancy in the seeds was tested at 12 °C using 6- and 18-h photoperiods. The optimal prechilling temperatures were between 1.0 and 3.3 °C. As the prechilling temperature increased, the effect of prechilling decreased so that the upper effective limit was between 8.7 and 12.0 °C. The effect of prechilling time on dormancy release was studied in an experiment where seeds prechilled at 2.4, 5.5, and 12.4 °C for 6, 12, 21, and 42 days were germinated at 12 °C using 6- and 18-h photoperiods. The germination probability (in logit scale) was directly related to the logarithm of the number of prechilling days. In seeds prechilled at 2.4 °C the requirement for a long photoperiod for germination was removed in 21 days, whereas 42 days were needed in seeds prechilled at 5.5 °C.
Time trends in genetic control over height and diameter in maritime pine
Authors: Costa P. , Durel C.E.
Published: January 2008

Height and diameter of 257 twenty-year-old maritime pine (Pinuspinaster Ait.) trees, originating from a factorial mating design, were subdivided in annual height increments (AHI) and annual diameter increments (ADI). Cumulative and annual data of both traits were compared using two different genetic models. The two traits exhibited very different genetic expressions. For cumulative data, the heritability increased steadily with age for height and was very stable for diameter. For annual data, this evolution did not reveal any particular trend for AHI but appeared much more stable for ADI. Different effects seemed to be involved in the variation of annual increments: year and residual effects were 5 and 2.5 times more important for AHI than for ADI, respectively; in contrast, family and individual effects were 10 and 15 times more important for ADI than for AHI, respectively. Serial correlations calculated at the full-sib family mean level also showed different patterns: low values and rapid decrease of correlations for successive AHI, and high values and a linear decrease for successive ADI. As trees aged, the genetic expression of height growth appeared to be more unstable than for diameter growth. Interpretations about these expressions and their consequences for early selection are discussed.
Stem number estimation by kernel smoothing of aerial photos
Authors: Dralle Kim , Rudemo Mats
Published: January 2008

A digitized aerial panchromatic photo of a thinning experiment in pure even-aged Norway spruce (Piceaabies (L.) Karst.) is smoothed by a two-dimensional isotropic Gaussian kernel. The number of stems per hectare is estimated from the number of maxima above a certain level of the smoothed image. For the crucial kernel bandwidth estimation problem we suggest a two-step procedure where the first step consists of computing (for each homogeneous stand (or subplot)) an "internal curve" corresponding to the number of maxima at a series of bandwidths. The estimated stem number and the optimal bandwidth is then obtained as the crossing of the internal curve with an "external curve," here assumed to be of a simple parametric form. If a series of stands (or subplots) with different known stem numbers is available, the external curve can be estimated by use of a nonlinear regression method. An experiment with 48-year-old trees and six subplots with varying thinning treatments is analyzed. The stem number estimation method, checked by cross validation, performs satisfactorily for all thinning grades except the unthinned control.
An 8-year field comparison of naturally seeded to planted container Pinustaeda, with and without release
Authors: Cain Michael D. , Barnett James P.
Published: January 2008

A field study compared genetically improved, container loblolly pines (Pinustaeda L.) with naturally seeded loblolly pines through eight growing seasons on a cutover site in southern Arkansas, U.S.A. Measurement pines on 6 of 12 plots were released from woody and herbaceous competition within a 61-cm radius of each tree stem. On natural pine plots, only 1st-year pine seedlings were selected for measurement based on quality standards and their spacing. Woody competition was controlled by hand cutting for 5 consecutive years, and herbaceous competition was controlled with herbicides for 4 consecutive years. Release treatments increased 8-year survival by 50% for natural pines and by 35% for planted pines. Greater gains (343–391%) in individual tree volumes were achieved within regeneration techniques, as a result of release, than were achieved with the two regeneration techniques. In addition, stand volume gains of 647% and 910% were achieved by planted and natural pines, respectively, as a result of release. Eight years after field establishment, stand volume index averaged 46% higher on planted plots than on natural plots. Degree of overtopping was a better predictor of pine performance than live-crown ratio.
Distribution of water-soluble organic carbon in an aspen forest soil
Authors: Huang W.Z. , Schoenau J.J.
Published: January 2008

The purpose of this study was to characterize the quantity, distribution, and variance of water-soluble organic C (WSOC) in a soil under trembling aspen (Populustremuloides Michx.) in the southern boreal forest of Canada. WSOC was determined monthly from May to October 1994 in the forest floor horizons (L, F, H) and mineral soil (Ae) of an aspen stand in Prince Albert National Park, Saskatchewan. The concentration of WSOC varied considerably with profile depth, but varied little among the slope positions and aspects. The L horizon had the highest WSOC concentration (425–8690 mg•kg−1 ovendried soil), followed by the F, H, and Ae horizons. The concentration of WSOC in the Ae horizon was significantly related to the concentration in forest floor horizons above. Water-soluble organic C in the Ae horizon likely was derived from the overlying organic layer by leaching. In a laboratory incubation, the rate of WSOC release (the net result of release and uptake) during incubation decreased continuously over time, but in the field, the rate of WSOC release decreased slightly early in the growing season, but increased later in the season as new litter fall reached the forest floor. This indicates that litter fall is a major factor in the replenishment of WSOC in aspen forest stands.
The dynamics of stand development: a general stand model applied to Douglas-fir
Authors: Tait David E.
Published: January 2008

A linked pair of hypotheses which represent causal explanations for plant growth and stand mortality for an even-aged stand are developed. The pair of dynamic equations lead to a four-parameter Douglas-fir simulation model. The four-parameter model relates the development of stand volume and density to site quality, initial stocking density, and alternative thinning regimes. The mortality hypothesis, a dynamic hypothesis related to stand density and stand growth, generates the −3/2 power law as an equilibrium solution.
Genetic variation of red spruce in the Maritimes
Authors: Fowler D. P. , Park Y. S. , Gordon A. G.
Published: January 2008

Red spruce, Picearubens Sarg., from 30 provenances was tested over a 23-year period at six locations in the Maritimes Region of Canada. Twenty-eight of the provenances were from the Maritimes Region and two were from West Virginia. Hybrid index was used to distinguish pure red spruce from red–black spruce derivatives. Trees from three of the Maritimes provenances were considered to be of hybrid origin. These three provenances produced the fastest-growing trees in the tests. The genetic variation pattern, at the provenance level, in pure red spruce of Maritimes origin is not well defined. Use of seed from provenances identified as superior for reforestation would result in about 10% greater height and diameter growth than would be obtained from average seed. The use of seed of poor provenances could result in a corresponding loss of growth. Height at ages 10, 15, and 23 years and diameter at age 23 years were all strongly correlated, suggesting that superior provenances of red spruce can be identified at age 10. The Maritimes Region can be considered as a single breeding zone for tree improvement efforts with red spruce.
Early growth of planted western hemlock in relation to stock type and controlled-release fertilizer application
Authors: Arnott J. T. , Burdett A. N.
Published: January 2008

Four types of western hemlock (Tsugaheterophylla (Raf.) Sarg.) nursery stock, differing in size, morphology, and root growth capacity were planted on a clear-cut forest site on Vancouver Island, British Columbia. The stock types were: (i) 1-year-old, plug-rooted seedlings raised in 36-cm3 containers; (ii) as (i) but transplanted to a bareroot nursery for 1 year; (iii) 1-year-old, bareroot seedlings raised in 1000-cm3 containers; (iv) as (iii) but raised in containers coated on the inside with copper paint to inhibit lateral root elongation upon contact with the container wall. Survival and growth of seedlings with and without fertilization at planting with 50 g of a slow-release (Nutricote®, 12-month release at 25 °C) N–P–K fertilizer were observed for 3 years. Neither stock type nor fertilizer had a statistically significant (P < 0.05) effect on seedling survival. At planting, plug seedlings were significantly (P < 0.01) shorter and smaller in stem volume than the other stock types. These differences were no longer evident by the end of the third growing season because of more rapid growth by the plug stock. The largest differences between the plugs and the other stock types in height and diameter relative growth rates occurred during the first growing season. Fertilization significantly (P < 0.01) increased height and stem volume relative growth rates of all stock types during the first growing season. During the third growing season fertilization had a significant (P < 0.01) negative effect on height, and diameter and stem volume relative growth rates of all stock types, but not on absolute rates. At the end of three growing seasons, fertilized trees remained significantly (P < 0.01) larger in all stock types than in the controls.
Development of a root growth model for yellow-poplar and sweetgum seedlings grown in compacted soil
Authors: Simmons G. L. , Pope P. E.
Published: January 2008

A root growth model was developed to graphically simulate predicted root responses of yellow-poplar and sweetgum seedlings to changes in soil physical properties. Data for the model were collected in greenhouse and laboratory experiments. Newly germinated yellow-poplar (Liriodendrontulipifera L.) and sweetgum (Liquidambarstyraciflua L.) seedlings were transplanted into pots containing silt loam soil compacted to bulk densities of 1.25, 1.40, or 1.55 Mg m−3 and grown under greenhouse conditions for 3 months. Minimum water potentials were maintained at −10 or −300 kPa. At harvest, root systems were excavated, divided into orders of lateral roots, and length, number, and branching frequency of each order were determined. Air-filled porosity and mechanical resistance were determined for soil samples equilibrated at the same bulk densities and water potentials as those used in the greenhouse study. Based on root and soil parameters, the model ROOTSIM graphically depicts the root distribution of each tree species at different levels of bulk density, mechanical resistance, and air-filled porosity. The model accurately predicts lateral root length and distribution for the range of soil properties used in the greenhouse study but has not been validated for these or other soil conditions.