bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of a weighing lysimeter system to assess the effects of trampling on evapotranspiration of montane plant communities
Authors: Scott David , Bayfield Neil G , Cernusca Alexander , Elston David A
Published: July 2002

The aim was to investigate the impacts of trampling on water loss and partitioning in vegetation with contrasting structure and species composition. A new design of weighing lysimeter was used in glasshouse experiments to compare evapotranspiration from intact and trampled blocks of vegetation. The lysimeter system was able to detect differences between treatments after only a few hours. Evapotranspiration was recorded for six communities, representative of cryptogam - vascular plant communities found in the Cairngorm Mountains of Scotland. Vegetation blocks of Racomitrium and Vaccinium/Hylocomium heath communities had the greatest cumulative evapotranspiration and lichen heath the least over 48 h. Blocks from three of the communities (Agrostis/Festuca grassland, Calluna wet heath, and lichen heath) were used in a trampling experiment with five levels of damage. Trampling progressively destroyed the structure of the vegetation of all communities and increased the rates of water loss from the blocks. The grassland community vegetation was the most resilient. These results help to link the massive changes in vegetation structure resulting from trampling to effects on water loss and microclimate.Key words: weighing lysimeter, evapotranspiration, recreation, trampling, cryptogams, montane vegetation.
Dormancy in peach (Prunus persica) flower buds. VI. Effects of gibberellins and an acylcyclohexanedione (trinexapac-ethyl) on bud morphogenesis in field experiments with orchard trees and on cuttings
Authors: Reinoso Herminda , Luna Virginia , Dauría Carlos , Pharis Richard P , Bottini Rubén
Published: July 2002

The effects of several gibberellins (GAs), exo-16,17-dihydro GA5, 2,2-dimethyl GA4, and GA3, and trinexapac-ethyl (an acylcyclohexanedione inhibitor of late-stage GA biosynthesis), were assessed for their effects on flower bud development during and after winter dormancy in peach (Prunus persica (L.) Batsch.) in three field trials and one experiment using cuttings. At late developmental stages, GA3hastened floral bud development and shortened the time to anthesis, whereas early-stage applications of GA3either had no effect or delayed floral bud development. In contrast, an exceptionally growth-active GA, 2,2-dimethyl GA4, promoted floral bud development (tested only on cuttings) across a range of application dates. However, it also induced a high percentage of bud abscission and remaining buds had a necrotic gynoecium and alterations in the androecium. Surprisingly, trinexapac-ethyl also promoted floral bud development, although it was not as effective as GA1. Trinexapac-ethyl-treated buds also showed morphological alterations and gynoecium necrosis. However, the best and most consistent treatment for enhancing floral bud development and hastening flower anthesis was 16,17-dihydro GA5. It stimulated floral bud development in up to 80% of the treated buds. Further, the promotive effect of 16,17-dihydro GA5was maintained through to anthesis across three years of field experiments on intact trees, as well as with cuttings. Whether 16,17-dihydro GA5, a competitive inhibitor of the 3β-hydroxylation step in GA biosynthesis, acts per se, acts via a metabolite (such as 16,17-dihydro GA3), or acts by modifying endogenous GA metabolism is not yet known.Key words: gibberellins, trinexapac-ethyl, floral bud morphogenesis, peach.
A U–Pb geochronological review of the Proterozoic history of the eastern Grenville Province
Authors: Gower Charles F , Krogh Thomas E
Published: July 2002

The geological evolution of the eastern Grenville Province can be subdivided into three stages. During the first stage, namely pre-Labradorian (> 1710 Ma) and Labradorian (17101600 Ma) events, a continental-marginal basin was created and subsequently destroyed during accretion of a magmatic arc formed over a south-dipping subduction zone. Subduction was short-lived and arrested, leading to a passive continental margin. The second stage addresses events between 1600 and 1230 Ma. The passive margin lasted until 1520 Ma, following which a continental-margin arc was constructed during Pinwarian (15201460 Ma) orogenesis. Elsonian (14601230 Ma) distal-inboard, mafic and anorthositic magmatism, decreasing in age northward, is explained by funnelled flat subduction, possibly associated with an overridden spreading centre. As the leading edge of the lower plate advanced, it was forced beneath the Paleoproterozoic Torngat orogen root between the Archean Superior and North Atlantic cratons, achieving its limit of penetration by 1290 Ma. Static north-northeast-trending rifting then ensued, with mafic magmatism flanked by felsic products to the north and south. Far-field orogenic effects heralded the third stage, lasting from 1230 to 955 Ma. Until 1180 Ma, the eastern Grenville Province was under the distal, mild influence of Elzevirian orogenesis. From 1180 to 1120 Ma, mafic and anorthositic magmatism occurred, attributed to back-arc tectonism inboard of a post-Elzevirian Laurentian margin. Quiescence then prevailed until Grenvillian (1080980 Ma) continentcontinent collision. Grenvillian orogenesis peaked in different places at different times as thrusting released stress, thereby precipitating its shift elsewhere (pressure-point orogenesis). High-grade metamorphism, thrusting and minor magmatism characterized the Exterior Thrust Zone, in contrast to voluminous magmatism in the Interior Magmatic Belt. Following final deformation, early posttectonic anorthositicalkalicmafic magmatism (985975 Ma) and late posttectonic monzoniticsyenitegranite magmatism (975955 Ma) brought the active geological evolution of this region to a close.
Late Ordovician brachiopod communities of southeast China
Authors: Zhan Ren-bin , Rong Jia-yu , Jin Jisuo , Cocks L RM
Published: July 2002

The Upper Ordovician (mid-Ashgill) Xiazhen and Changwu formations in the Zhejiang-Jiangxi border region of southeastern China contain an abundant and diverse suite of brachiopods. A cluster analysis of 59 key samples from 180 collections (over 23 000 specimens) allowed delineation of eight distinct brachiopod communities, herein named the Ectenoglossa minor Community, the Eospirifer praecursor Community, the Ovalospira dichotoma Community, the Antizygospira liquanensis  Sowerbyella sinensis Community, the Kassinella shiyangensis Community, the Altaethyrella zhejiangensis Community, the Tcherskidium jiangshanensis Community and the Foliomena folium Community. These communities occur predominantly in limey, clayey, to silty mudstone facies, similar to Ziegler's Early Silurian brachiopod communities in the Welsh Borderland. On the basis of lithological, faunal, and paleogeographical evidence, the eight communities are interpreted to have distributed along an onshoreoffshore gradient from BA1 to BA6 settings on the northeastern margin of the Zhe-Gan Platform. In a broad paleo-embayment and mixed carbonatesiliciclastic shelf setting, the distribution of the eight brachiopod communities appears to have been controlled primarily by water depth because a given brachiopod community can be found in different lithofacies. Substrate types, however, must have played an important role, as some of the communities show preferred lithofacies. This study shows that the ecological zonation and community organization of the Late Ordovician pre-extinction brachiopods were similar to those of Early Silurian post-extinction brachiopods, although pronounced brachiopod provincialism during the Ashgill makes it difficult to directly correlate these communities with coeval brachiopod communities reported from other paleo-plates.
Anatomy and orogenic history of a Paleoproterozoic accretionary belt: the Makkovik Province, Labrador, Canada
Authors: Ketchum John W.F , Culshaw Nicholas G , Barr Sandra M
Published: July 2002

The Makkovik Province is a segment of a Paleoproterozoic accretionary belt (the MakkovikKetilidian orogen) that developed on the southern margin of Laurentia at 1.91.7 Ga. In contrast to coeval Laurentian orogenic belts that mainly resulted from collision of Archean plates, MakkovikianKetilidian orogenesis was dominated by active-margin processes including continental margin arc plutonism and juvenile terrane accretion, both of which were accompanied by regional transpression. In the Makkovik Province, earliest deformation and amphibolite-facies metamorphism of Paleoproterozoic riftdrift assemblages (Post Hill and Moran Lake groups) and the Archean foreland (Nain Province) occurred at 1.9 Ga in response to accretion of a Paleoproterozoic island arc. Following this collision, cratonward-dipping subduction was established, resulting in the formation of the 18951870 Ma Island Harbour Bay Plutonic Suite, a calc-alkaline magmatic arc built on reworked Archean crust. Crust formation continued between ca. 1860 and 1850 Ma with deposition of the Aillik Group on a largely juvenile basement in a rifted-arc or back-arc setting. Sometime before 1802 Ma this depositional basin was tectonically inverted, with resultant northwestward thrusting of the Aillik Group over reworked Archean crust. This phase of deformation may have been driven by accretion of a second island arc potentially represented by the Cape Harrison Metamorphic Suite. Regional transpression and amphibolite-facies metamorphism at ca. 18151780 Ma were accompanied by widespread granitoid plutonism. These events were mainly concentrated in the juvenile domains and are thought to reflect processes in a broad continental back-arc setting. A final orogenic pulse, marked by regional greenschist-facies transpression and emplacement of A-type granitoid plutons, occurred between 1740 and 1700 Ma, with deformation and plutonism potentially linked to crustmantle detachment and incursion of mafic magmas at the base of the crust, respectively. The record of crustal development suggests that the coeval themes of spatially and temporally linked structural and plutonic activity, oceanward migration of this activity over time, and a trend toward increasingly more localized deformation occurred throughout the orogenic history of the Makkovik Province. These characteristics are thought to broadly reflect oceanward crustal growth of the orogen over time. In the correlative Ketilidian mobile belt of southern Greenland, these themes were also operative but appear to have been less pronounced, most likely due to minimal or a complete absence of accretion of island-arc material.
Geophysical characteristics of the continental crust along the Lithoprobe Eastern Canadian Shield Onshore–Offshore Transect (ECSOOT): a review
Authors: Hall Jeremy , Louden Keith E , Funck Thomas , Deemer Sharon
Published: July 2002

The Eastern Canadian Shield OnshoreOffshore Transect (ECSOOT) of the Lithoprobe program included 1200 km of normal-incidence seismic profiles and seven wide-angle seismic profiles across Archean and Proterozoic rocks of Labrador, northern Quebec, and the surrounding marine areas. Archean crust is 3344 km thick. P-wave velocity increases downwards from 6.0 to 6.9 km/s. There is moderate crustal reflectivity, but the reflection Moho is unclear. Archean crust that stabilized in the Proterozoic is similar except for greater reflectivity and a well-defined Moho. Proterozoic crust has similar or greater thickness, variable lower crustal velocities, and strong crustal reflectivity. Geodynamic processes of Paleoproterozoic growth of the Canadian Shield are similar to those observed in modern collisional orogens. The suturing of the Archean Core Zone and Superior provinces involved whole-crustal shearing (top to west) in the Core Zone, linked to thin-skinned deformation in the New Quebec Orogen. The Torngat Orogen sutures the Nain Province to the Core Zone and reveals a crustal root, in which Moho descends to 55 km. It formed by transpression and survived because of the lack of postorogenic heating. Accretion of the Makkovik Province to the Nain Province involves delamination at the Moho and distributed strain in the juvenile arcs. Delamination within the lower crust characterizes the accretion of Labradorian crust in the southeastern Grenville Province. Thinning of the crust northwards across the Grenville Front is accentuated by Mesozoic extension that reactivates Proterozoic shear zones. The intrusion of the Mesoproterozoic Nain Plutonic Suite is attributed to a mantle plume ponding at the base of the crust.
Correlation chart of the eastern Grenville Province and its northern foreland
Authors: Gower Charles F , Krogh Thomas E , James D T
Published: July 2002

Chart 2: Correlation chart of the eastern Grenville Province and its northern Foreland, including a location map showing regional geological subdivisions and reference list.
The High Pressure belt in the Grenville Province: architecture, timing, and exhumation
Authors: Rivers Toby , Ketchum John , Indares Aphrodite , Hynes Andrew
Published: July 2002

We propose that the Grenvillian allochthonous terranes may be grouped into High Pressure (HP) and Low Pressure (LP) belts and examine the HP belt in detail in the western and central Grenville Province. The HP belt is developed in Paleo- and Mesoproterozoic rocks of the pre-Grenvillian Laurentian margin and characterized by Grenvillian eclogite and co-facial HP granulite in mafic rocks. Pressuretemperature (PT) estimates for eclogite-facies conditions in well-preserved assemblages are about 1800 MPa and 850°C. In the central Grenville Province, HP rocks formed at ~10601040 Ma and underwent a single stage of unroofing with transport into the upper crust by ~1020 Ma, whereas farther west they underwent two stages of unroofing separated by penetrative mid-crustal recrystallization before transport to the upper crust at ~1020 Ma. Unroofing processes were comparable in the two areas, involving both thrusting and extensional faulting in an orogen propagating into its foreland by understacking. In detail, thrusting episodes preceded extension in the western Grenville Province, whereas in the central Grenville Province, they were coeval, resulting in unroofing by tectonic extrusion. In the central Grenville Province, the footwall ramp is well preserved, but any former ramp in the western Grenville Province was obliterated by later lower crustal extensional flow. Continuation of the HP belt into the eastern Grenville Province is not established, but likely on geological grounds. However, the pattern of deep crustal seismic reflection in the Lithoprobe Eastern Canadian Shield OnshoreOffshore Transect (ECSOOT) line contrasts with that father west, suggesting that, if present, the HP rocks were exhumed by a different mechanism.
The Nagssugtoqidian Orogen of West Greenland: tectonic evolution and regional correlations from a West Greenland perspective
Authors: van Gool Jeroen A.M , Connelly James N , Marker Mogens , Mengel Flemming C
Published: July 2002

The Nagssugtoqidian Orogen of West Greenland represents a belt of Palaeoproterozoic deformation and metamorphism between the North Atlantic Craton of South Greenland and a northern, lesser known continental segment that includes the Rinkian Orogen. First-order observations are interpreted to support a cycle of separation, convergence, and eventual collision of two continental masses. The emplacement of the Kangâmiut dyke swarm marked the onset of continental breakup at ca. 2040 Ma, and sedimentary basins formed between ca. 1950 and 1920 Ma. Subsequent convergence and consumption of an oceanic plate caused arc magmatism at 19201870 Ma. Granulite-facies peak metamorphism at 18601840 Ma in the centre of the orogen is related to crustal thickening by WNW-directed thrusting. Large-scale, upright folding with an eastwest trend was ongoing by 1825 Ma. Sinistral strike-slip movement was concentrated along steeply dipping limbs of these large-scale folds and formed orogen-scale steep belts at ca. 1775 Ma. Close similarities between the northern and southern foreland suggest that the two cratons likely originated from one continuous continental block. Temporal and kinematic correlation of these events with adjoining orogens in Canada and Greenland shows close genetic links. The Nagssugtoqidian Orogen of West Greenland continues eastwards beneath the Greenland Ice cap to the Eastern Nagssugtoqidian belt of East Greenland (a.k.a. the Ammassalik belt). The Torngat Orogen of eastern Canada developed simultaneous with the Nagssugtoqidian Orogen with a kinematic compatibility suggesting that the two orogens formed on the west and north flanks, respectively, of a curved leading continental margin of an indenting North Atlantic Craton.
Atlantic mackerel (Scomber scombrus) recruitment fluctuations in relation to copepod production and juvenile growth
Authors: Ringuette Marc , Castonguay Martin , Runge Jeffrey A , Grégoire François
Published: July 2002

A previous study identified relationships linking variations in the physical environment to fluctuations in zooplankton biomass and Atlantic mackerel (Scomber scombrus) recruitment. Diets of mackerel larvae were compared among four years, one of these years producing an exceptional year-class (1982). Comparisons were standardized for larval length and time of day. Stomach fullness differed significantly among years, with highest values observed in 1982. Stomach content wet weights were significantly larger in 1982 than in 1987 and 1996. The mean weight of Calanus finmarchicus nauplii prey in the diet was also significantly greater in 1982 than in 1985, 1987, or 1996. Female C. finmarchicus were more abundant and more widely distributed in the southern Gulf of St. Lawrence in 1982 compared with 1985, 1987, and 1990. These findings are consistent with the hypothesis of a link between production of copepod nauplii, feeding of mackerel larvae, and recruitment success. However, mackerel size at the end of the first year, as measured on otoliths, varied significantly between years and was smallest in 1982. We propose hypotheses to account for the coupling between high larval food abundance, small juvenile growth, and strong cohorts.
Biocatalyzed preparation of the optically enriched stereoisomers of 4-methyl-2-phenyl-tetrahydro-2H-pyran (Doremox®)
Authors: Brenna Elisabetta , Fuganti Claudio , Ronzani Sabrina , Serra Stefano
Published: July 2002

The four stereoisomers of the rose oxide analogue Doremox®were prepared in enantiomerically enriched form by enantiospecific bakers' yeast reduction of suitable derivatives and by lipase-mediated kinetic resolution of diol precursors.Key words: yeast, lipase, odorant, reduction, kinetic resolution.
Methylamine adenine dinucleotide (MAD): a co-factor to turn alcohol dehydrogenases into aldolases
Authors: Wahler Denis , Reymond Jean-Louis
Published: July 2002

Methylamine adenine dinucleotide (MAD) was prepared in seven steps and 15.3% overall yield from 1-acetoxy-2,3,5-tri-O-benzoyl-D-ribose by chemoenzymatic synthesis. The key step was the phosphatephosphate coupling between adenosine monophosphate and 2,5-anhydro-1-deoxy-1-phenylacetamide-6-phosphate-D-allitol (3) mediated by carbonyl diimidazole (CDI), followed by the removal of the phenylacetamido group by penicillin G acylase. The MAD co-factor provided a primary amine functionality that was suitably positioned to promote the enamine aldolization of 2-oxopropionamide with aldehydes within the active site of alcohol dehydrogenases, which should lead to the transformation of these stereoselective enzymes into aldolases. Preliminary investigations did not reveal any activity with horse liver alcohol dehydrogenase or yeast alcohol dehydrogenase.Key words: aldolases, alcohol dehydrogenases, co-factor enginering, nucleosides, acylases.
The CP4 transgene provides high levels of tolerance to Roundup® herbicide in field-grown hybrid poplars
Authors: Meilan R , Han K -H , Ma C , DiFazio S P , Eaton J A , Hoien E A , Stanton B J , Crockett R P , Taylor M L , James R R , Skinner J S , Jouanin L , Pilate G , Strauss S H
Published: July 2002

We tested two genes together in hybrid poplars (genus Populus), CP4 and GOX, for imparting tolerance to glyphosate (the active ingredient in Roundup® herbicide). Using Agrobacterium-based transformation, 80 independent transgenic lines (i.e., products of asexual gene transfer) were produced in a variety of hybrid poplar clones (40 lines in Populus trichocarpa Torr. & Gray × Populus deltoides Bartr., 35 lines in Populus tremula L. × Populus alba L., and five lines in P. tremula × Populus tremuloides Michx.). We evaluated glyphosate tolerance over 2 years in field studies conducted in eastern and western Oregon. Ten percent of our transgenic lines showed no foliar damage or reduced growth after being sprayed with Roundup® at concentrations above normal commercial rates. Lack of damage was associated with expression of the CP4 gene but not of the GOX gene. It was suspected that GOX caused undesirable side effects, so we produced 12 lines into which only the CP4 gene was inserted. The performance of these newly regenerated lines was compared with an identical number of lines, produced in the same genotype, that had previously been engineered to contain both CP4 and GOX. Growth of the lines transformed with just CP4 was significantly better than those containing both genes and exhibited less damage in response to glyphosate treatment. This is the first report of transgenic poplars exhibiting high levels of glyphosate tolerance when grown under field conditions. With a modest transformation effort, it is possible to produce lines with commercially useful levels of glyphosate tolerance and little apparent collateral genetic damage.
Foliar litter position and decomposition in a fire-maintained longleaf pine  wiregrass ecosystem
Authors: Hendricks Joseph J , Wilson Carlos A , Boring Lindsay R
Published: July 2002

Foliar litter position and decomposition were assessed in longleaf pine (Pinus palustris Mill.) - wiregrass (Aristida beyrichiana Trin. & Rupr.) woodlands during a 3-year burn interval. Position assessments revealed 57.7 and 67.4% of foliar litter was elevated in wiregrass crowns 1 and 2 years, respectively, following burning. Decomposition assessments revealed soil-surface mass loss decay constants (range 0.0970.282) similar to those measured in comparable pine forests. However, elevated longleaf pine and wiregrass litter exhibited decay constants (0.052 and 0.074, respectively) 50% lower than corresponding soil-surface rates and among the lowest values in the literature. With the exception of wiregrass, which did not exhibit an immobilization of the nutrients (N, P, Ca, K, and Mg) assessed, foliar litter exhibited either extensive P immobilization with minimal N immobilization or minimal, short-lived immobilization of N, P, or both N and P. The percentage of original N and P remaining after 3 years varied widely among the soil surface (N range 6.356.3%; P range 3.4204.7%) and elevated (N range 76.894.9%; P range 52.099.2%) litter. These results suggest that fire regimes typically employed in longleaf pine  wiregrass woodlands may balance N losses via volatilization with P limitations via litter immobilization.
Development of size hierarchies prior to the onset of density-dependent mortality in irrigated and fertilized loblolly pine stands
Authors: Nilsson U , Albaugh T J , Allen H L
Published: July 2002

Nine years of growth and stand development were investigated in a 2 × 2 nutrient and water factorial experiment with four replications. The study was located on an infertile, excessively drained sandy site in Scotland County, North Carolina, U.S.A. The hypothesis tested was that increased growth following irrigation and fertilization would increase the rate at which size hierarchies develop. The hypothesis was investigated by comparing the coefficient of variation (CV) of stem volume over time and examining the stem volume relative growth rate (RGR) of trees of different initial size in control and irrigated + fertilized stands. Even though there were no statistically significant differences in CV among treatments, there was a tendency for increased CV over time in the control stands, whereas CV initially increased, then decreased, and became constant in the irrigated + fertilized plots. The lack of increase in CV in the irrigated + fertilized plots was explained by unusually low variation in RGR across tree size classes and negative relation of RGR and size. Therefore, the hypothesis that increased growth resulted in a more rapid development of size hierarchies was rejected. The high RGR of small trees in the irrigated + fertilized treatment could not be explained by differences in vertical distribution of needles compared with the control treatment. Small trees in the irrigated + fertilized plots were overtopped by neighboring trees to the same degree as small trees in the control plots.
Bryophyte and lichen communities in mature to old-growth stands in eastern boreal forests of Canada
Authors: Boudreault Catherine , Bergeron Yves , Gauthier Sylvie , Drapeau Pierre
Published: July 2002

We sampled 22 black spruce (Picea mariana) - feathermoss (Pleurozium schreberi) sites (80 to >200 years) to describe and assess the diversity of bryophyte and lichen communities as a function of time since fire and site characteristics. Old growth had no more species than younger forests. We think that this result might be explained by the phenomenon of paludification, which is a major process in this region. Axis 1 of a nonmetric multidimensional scaling ordination (NMS) of terricolous species was interpreted as a paludification gradient. Mature forests were characterized by Pleurozium schreberi, Ptilium crista-castrensis, Polytrichum commune, and Dicranum polysetum, and older sites by a greater abundance of Sphagnum. Axis 1 of epiphytic species ordination (NMS) was interpreted as a gradient of time since the last fire. Abundance of Tuckermannopsis americana, Hypogymnia physodes, and Bryoria furcellata was greater in mature forests. In contrast, Mycoblastus sanguinarius, Bryoria trichodes, and Usnea spp. were more abundant in older forests. The abundance of epiphytic lichens increased with tree age, whereas their richness was higher in sites where trembling aspen (Populus tremuloides) and jack pine (Pinus banksiana) were present. Since species composition varied with time since the last fire, it is important to preserve the diversity of successional stages at the landscape level and the structural diversity at the stand level to maintain the bryophyte and lichen communities.
Initiation of an old-growth Douglas-fir stand in the Pacific Northwest: a reconstruction from tree-ring records
Authors: Winter Linda E , Brubaker Linda B , Franklin Jerry F , Miller Eric A , DeWitt Donald Q
Published: July 2002

We used tree-ring records to reconstruct the stand initiation of an old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stand in the western Cascade Range of southern Washington. All tree-ring samples were prepared and crossdated. Following a stand-replacing fire, the stand initiation period lasted from 1500 to 1540, with gradual filling-in of growing space over this period. All sampled Douglas-fir were initial colonizers, establishing (at stump-height) 15001521 under open conditions. A small number of the sampled western hemlock (Tsuga heterophylla (Raf.) Sarg.) were also initial colonizers. Growing space filled as tree crowns widened, and by 1540, closed forest conditions had developed. At this time, Douglas-fir were spaced about 3.5 m from equivalent competitors (ca. 800 trees/ha). In the centuries following canopy closure, considerable natural thinning of the initial colonizers occurred, but the canopy never opened enough again to allow further Douglas-fir establishment. Surviving Douglas-fir developed deep crowns despite the narrow initial spacing, and without epicormic branching from the bole. Most western hemlock that were canopy trees in 1992 established after 1540, originating in the understory. This reconstruction provides an example that may be useful where management policies emphasize the development of old-growth structures.
Effects of naloxone benzoylhydrazone on native and recombinant nociceptin/orphanin FQ receptors
Authors: Bigoni R , Calò G , Rizzi A , Okawa H , Regoli D , Smart D , Lambert D G
Published: July 2002

We have studied the effects of naloxone benzoylhydrazone (NalBzoH) at recombinant human OP4 receptors expressed in Chinese hamster ovary (CHO) cells (CHOhOP4) and native OP4 sites in isolated tissues from various species. In CHOhOP4 membranes, nociceptin (NC) and NalBzoH displaced [125I]Tyr14-NC with pKi values of 10.1 and 7.3. In the presence of 100 µM GDP, NC stimulated GTPγ35S binding (pEC50 = 8.5). NalBzoH was ineffective but antagonized the effects of NC (pA2 = 6.9). At 5 µM GDP, there was an increase in potency (pEC50 = 9.3) and efficacy (4.3-fold) of NC. NalBzOH was a partial agonist (pEC50 = 7.0, Emax = 13% relative to NC). In CHOhOP4 cells, NC and NalBzoH inhibited cAMP formation with pEC50 and Emax values of 9.8 and 100% and 6.0 and 44%, respectively. In the rat vas deferens, NalBzoH (10 µM) did not modify electrically induced twitches but competitively antagonized the inhibitory action of NC (pA2 = 6.2). In the mouse vas deferens (mVD) and guinea pig ileum (gpI), NalBzoH inhibited twitches with pEC50 and Emax values of 7.6 and 78% and 8.5 and 77%, respectively. The effect of 3 µM NalBzoH was fully inhibited by 3 µM naloxone in mVD and 30 µM in gpI. Under these conditions, NalBzoH antagonized the actions of NC in both preparations with pA2 values of 6.3 and 6.8, respectively. Collectively, these data demonstrate that NalBzoH is a nonselective OP4 ligand with system-dependent behaviour.Key words: nociceptin/orphanin FQ, naloxone benzoylhydrazone, OP4 receptors, cAMP, GTPγS, bioassay.
Simultaneous changes in intracellular calcium and tension induced by endothelin-1 and sarafotoxin S6c in guinea pig isolated gallbladder: influence of indomethacin
Authors: Cardozo Alcíbia M , D'Orléans-Juste Pedro , Bkaily Ghassan , Rae Giles A
Published: July 2002

The relationships between changes in intracellular Ca2+ and smooth muscle tension triggered by endothelin-1 and the selective endothelin ETB receptor agonist sarafotoxin S6c, as well as their susceptibility to modification by the nonselective cyclooxygenase blocker indomethacin, were assessed in guinea pig isolated gallbladder strips. Cumulative additions of either agonist (1, 10, and 100 nM) induced simultaneous graded, strongly correlated, slowly developing, and sustained changes in tension and intracellular Ca+2 (Fura-2 technique). Sarafotoxin S6c was more effective than endothelin-1 in raising intracellular Ca2+ at 1 or 10 nM, but their abilities to cause contractions were similar at all concentrations. Indomethacin (5.6 µM) markedly inhibited the changes in both intracellular Ca2+ and tension caused by all concentrations of sarafotoxin S6c (in response to 100 nM, increases in Ca+2 fluorescence intensity and tension were inhibited from 7.7 ± 0.7 to 4.0 ± 0.4% and from 460 ± 100 to 160 ± 40 mg, respectively) but only reduced the contraction triggered by 100 nM endothelin-1 (from 560 ± 100 to 230 ± 70 mg). Endothelin-1 caused greater prostacyclin release from gallbladder than sarafotoxin S6c (at 100 nM, 6-keto-PGF1α levels in the medium rose 4.8- and 2.8-fold, respectively; P < 0.05) and slightly increased thromboxane A2 release (1.6-fold; P < 0.05). Thus, gallbladder contractions triggered by combined ETA/ETB or selective ETB receptor stimulation (with endothelin-1 or sarafotoxin S6c, respectively) are strongly correlated with increases in intracellular Ca2+ but differentially affected by indomethacin. It remains to be assessed if this difference is because endothelin-1 triggers greater prostacyclin release than sarafotoxin S6c and (or) is due to the coupling of ETA and ETB receptors to distinct patterns of generation of cyclooxygenase-derived eicosanoids.Key words: endothelin, gallbladder, prostacyclin, indomethacin, calcium.
Systemic site of action for pressor effect of angiotensin II injected into the fourth cerebral ventricle of rats?
Authors: Pesquero João B , Fior-Chadi Debora R , Yu Yun-Guo , Merjan Antonio J , Lindsey Charles J , Paiva Antonio CM
Published: July 2002

Angiotensin II (ANG II) causes a systemic pressor effect when injected into the cerebral ventricles. In the rat fourth ventricle, the effective doses for the ANG II pressor effect are over 100 times larger than in the systemic circulation. Considering the discrepancy of doses, the possibility that ANG II may reach the systemic circulation and promote pressor effects, following injection into the fourth ventricle, was investigated. The effects on blood pressure of different vasoactive peptides that produce pressor responses when injected into the central nervous system were compared. Doseresponse curves were obtained for intravenous or fourth cerebroventricular injections of ANG II, lysyl-vasopressin (LVP), bradykinin (BK), or endothelin-1 (ET-1). The ED50 ratios for intracerebroventricular/intraveneous injections were 110 for ANG II, 109 for LVP, 0.01 for BK, and approximately 0.4 for ET-1. In cross-circulation preparations, pressor responses occurred in the donor rat following injection into the fourth cerebral ventricle of the recipient animal, showing that effective doses of ANG II, administered to the fourth cerebral, reach the systemic circulation. The same results were obtained for the microinjection of 4 nmol of LVP into the fourth cerebral ventricle of recipient animals. High-performance reverse-phase liquid chromatography analyses of arterial blood showed that approximately 1% of the [125I]ANG II injected into the fourth cerebral ventricle may be recovered from the systemic circulation a few seconds after the microinjection. The systemic administration of the ANG II receptor antagonist losartan blocked the response to ANG II injected into the fourth ventricle whereas antagonist administration in the same ventricle did not. Angiotensin injections into the lateral ventricle produced pressor responses that were reduced by antagonist administration to the same ventricle but not by systemic administration of the antagonist. The data suggest that the pressor effect resulting from ANG II or LVP injections into the fourth cerebral ventricle may be due to the action of this peptide in the systemic circulation. On the other hand, the pressor effect due to ANG II microinjection into the lateral ventricle apparently results from the direct stimulation of central periventricular structures.Key words: angiotensin, cerebral ventricles, pressor effect, systemic action.
Hyperhydration induced by glycerol ingestion: hormonal and renal responses
Authors: Melin Bruno , Jimenez Chantal , Koulmann Nathalie , Allevard Anne-Marie , Gharib Claude
Published: July 2002

The simultaneous time courses of hydromineral hormones (reninaldosterone system, arginine vasopressin, and atrial natriuretic peptide) and renal responses were examined during and after the completion of hyperhydration induced by glycerol and fluid ingestion. Eight healthy young male Caucasian subjects participated in two separate trials, each including three consecutive phases in a thermoneutral environment. Phases 1 and 3 involved a 90-min period at rest, while phase 2 involved a 120-min period at rest designed to provide either (i) euhydration (control trial) or (ii) hyperhydration induced by ingestion of glycerol (1.1 g/kg body mass) and fluid (21.4 mL/kg body mass). During the 2-h time period of glycerol and fluid ingestion, urine flow, urine osmolality, and plasma levels of hydromineral hormones remained at basal values. In contrast, after hyperhydration completion during phase 3, the diuresis increased markedly together with a dilution of the urine (p < 0.05) while hormonal responses did not change. These results indicate significant differences in renal responses during and after hyperhydration completion and suggest that these changes are independent of fluid-regulating hormonal responses.Key words: glycerol, hyperhydration, fluid-regulating hormones, renal responses.
Functional and autoradiographic characterization of dopamine D2-like receptors in the guinea pig heart
Authors: Gómez María de Jesús , Rousseau Guy , Nadeau Réginald , Berra Roberto , Flores Gonzalo , Suárez Jorge
Published: July 2002

Dopamine receptors include the D1- (D1and D5subtypes) and D2-like (D2, D3, and D4subtypes) families. D1-like receptors are positively and D2-like receptors negatively coupled to the adenylyl cyclase. Dopamine D2-like (D4subtype) receptors have been identified in human and rat hearts. However the presence of D2and D3receptor subtypes is unclear. Furthermore, their role in cardiac functions is unknown. By autoradiographic studies of guinea pig hearts, we identified D3and D4receptors, using the selective radioligands [3H]-7-OH-DPAT and [3H]emonapride (YM-09151-2 plus raclopride). Western blot analysis confirmed D3and D4receptors in the right and left ventricle of the same species. Selective agonists of D3and D4receptors (±)-7-OH-DPAT and PD 168 077 (109to 105M, respectively) induced a significant negative chronotropic and inotropic effect in the isolated guinea pig heart preparation. Negative inotropic effect induced by PD 168 077 was associated with an inhibition in cyclase activity. No changes in cyclase activity were found with (±)-7-OH-DPAT. The aim of this study is to support the presence of D3and D4receptors in the heart. Although our results suggest that D3and D4receptors are functionally active in the heart, we need additional information with an antagonist and an agonist of improved potency and selectivity to understand the respective roles of D3and D4receptors in the cardiac functions.Key words: Dopamine receptors (D2, D3, D4subtypes), autoradiography, Western blot, cAMP, heart.
Genetic fragmentation of populations of the fluvial sculpinCottus nozawae(Pisces: Cottidae) at the southern margin of its native range
Authors: Yagami Tetsuhiko , Yokoyama Ryota , Goto Akira
Published: July 2002

The influence of fragmentation on local genetic population structure of the fluvial sculpin Cottus nozawae was studied by comparing populations in two regions: the Tohoku District (the southern margin of the species' native range) and Hokkaido Island (the center of its native range), Japan, based on restriction fragment length polymorphism analysis of mitochondrial DNA amplified by means of the polymerase chain reaction. Relatively high genetic divergences were found among populations from different regions. An analysis of molecular variance showed that ΦSTvalues among samples from the same river system in the Tohoku District were higher than among samples from Hokkaido Island. Heterogeneities in haplotype composition among tributary populations and among distinctive clusters were also found in the Tohoku District river system. Cottus nozawae in the Tohoku District are distributed patchily in headwater streams and may be thermally isolated. As a result, there appears to be little gene flow among tributary populations from different areas that exhibit divergence due to random genetic drift and have small effective population sizes.
Transgenerational effects of maternal immune challenge in tree swallows (Tachycineta bicolor)
Authors: Lozano G A , Ydenberg R C
Published: July 2002

The fact that avian eggs contain antibody of maternal origin is well documented, but only recently has this phenomenon been considered in an ecological context. We used tree swallows (Tachycineta bicolor) to examine the possibility of transgenerational immunity and its effect on nestling growth and immune development. We measured cell-mediated immunity with a delayed-hypersensitivity assay and antibody-mediated immunity with a hemagglutination test with sheep red blood cells (SRBCs). We tested for differences in immunocompetence and growth between nestlings from females who had been exposed to a novel antigen prior to egg laying and nestlings from unexposed females. To determine whether the effect, if any, resulted from something transferred to the eggs prior to egg laying or from subsequent changes in parental behaviour, nestlings were exchanged so that at each nest half the nestlings were from females who had been injected with SRBCs and half were from females who had not been exposed to SRBCs. Finally, brood sizes were independently manipulated to either 4 or 6 nestlings. We failed to detect maternal antibodies in any nestlings, and whether a female was exposed to SRBCs or not had no effect on the growth or cell-mediated immunity of her brood. However, nestlings in smaller broods grew better than nestlings in larger broods, though we did not find the expected differences in cell-mediated immunity. Furthermore, within each nest, nestlings whose mothers had been exposed to SRBCs grew better than nestlings whose mothers had not been exposed. These results are contrary to the idea of a simple trade-off in the allocation of resources between parasite protection and reproduction; however, they support the idea that exposure of females to parasites prior to egg laying leads to better nestling growth, and are congruous with the possibility of mithridatic parental care.
The presence of the male facilitates parturition in California mice (Peromyscus californicus)
Authors: Lee Anna W , Brown Richard E
Published: July 2002

The California mouse (Peromyscus californicus) is a monogamous species with biparental care. The present study investigated the behaviour of the male during parturition and compared the behaviour of females that gave birth when in malefemale pairs with that of females whose mate was removed 2 days prior to the expected birth date and thus gave birth alone. Parturitions were videotaped and the behaviour of each mouse was analyzed during parturition and during the 15 min before and 15 min after parturition. The results showed that males licked the anogenital region of the female, ate the placenta, and exhibited parental care as soon as the pups were born. Females in pairs received more body grooming and anogenital stimulation during parturition than females alone, owing to the additional licking received from their mate. In addition, pups born with the father present received more licking during and after parturition than pups born to females housed alone. Removal of the male near the end of the gestation period delayed parturition by 1 day. These results show that male California mice participate in the birth process by assisting the female and caring for pups, and that the presence of the male during the gestation period may facilitate parturition.
Myoglobin deficiency in the hearts of phylogenetically diverse temperate-zone fish species
Authors: Grove Theresa J , Sidell Bruce D
Published: July 2002

Previous studies relying upon spectrophotometric methods reported low levels of myoglobin, an intracellular oxygen-binding protein, in oxidative muscles of some sluggish benthic fishes distributed throughout the North Atlantic Ocean. Using immunochemical techniques we show that myoglobin is not expressed in the heart ventricles of Cyclop terus lumpus (Cyclopteridae), Anarhichas lupus (Anarhichadidae), Macrozoarces americanus (Zoarcidae), and Lophius americanus (Lophiidae). Hemitripterus americanus (Hemitripteridae) expresses myoglobin at 2.3 ± 0.2 mg·g wet mass1(mean ± SD). Myoglobin was not detected in oxidative skeletal muscle (pectoral adductor profundus) in either the white-hearted fishes examined or red-hearted H. americanus. Supporting these results, myoglobin messenger RNA was not detected in cardiac muscles of white-hearted fishes by means of either direct Northern blot analysis or by the reverse transcriptase  polymerase chain reaction followed by amplification of cDNA product. The partial cDNA sequence of H. americanus myoglobin was determined and shows 86.9% identity with a known teleost myoglobin cDNA from Chionodraco rastrospinosus. The 3' untranslated region of H. americanus is 255 nucleotides longer than the 3' untranslated region of C. rastrospinosus. Comparisons of the deduced amino acid sequence of H. americanus with those of other teleosts show 66.2% sequence identity with Cyprinus carpio, 74.6% with Scomber japonicus, and 80.3% with Thunnus albacares and C. rastrospinosus.
BOUNDEDNESS FOR CODIMENSION TWO SUBVARIETIES
Authors: CILIBERT CIRO , DI GENNARO VINCENZO
Published: July 2002

We prove that for certain projective varieties V ⊂ Pr (e.g. smooth complete intersections with dim (V) ≥ 4, or complete intersections with dim (V) ≥ 7 and codim V ( Sing (V)) ≥ 6), there are only finitely many components of the Hilbert scheme parametrizing irreducible, smooth, projective, codimension two subvarieties of V not of general type.
μCF STUDY OF D/T AND H/D/T MIXTURES IN HOMOGENEOUS AND INHOMOGENEOUS MEDIUM, AND COMPARISON OF THEIR FUSION YIELDS
Authors: ESKANDARI M. R. , FAGHIHI F. , GHEISARI R.
Published: July 2002

Muon reactivation coefficient are determined for muonic He [Formula: see text] for up to six (n = 1, 2, 3, …, 6) states of formation and at temperature Tp = 100 eV and for various relative ion densities. In the next decade it may be possible to explore new conditions for further energy gain in muon catalyzed fusion system, μCF, using nonuniform (temperature and density) plasma states. Here, we have considered a model for inhomogeneous μCF for mixtures of D/T and H/D/T. Using coupled dynamical equations it is shown that the neutrons yield per muon injection, Yn (neutrons/muon), in the dt branch of an inhomogeneous H/D/T mixture is at least 2.24 times higher than similar homogeneous systems and this rate for a D/T mixture is 1.92. Also, we have compared the neutron yield in the dt branch of homogeneous D/T and H/D/T mixtures (temperature range T = 300–800 K , and density ϕ = 1 LHD). It is shown that Yn(D/T)/Yn(H/D/T) = 1.32, which is in good agreement with recently measured experimental values. In other words our calculations show that the addition of protonium to a D/T mixture leads to a significant decrease in the cycling rate for the physical conditions described herein.
HAMILTONIAN COHOMOLOGICAL DERIVATION OF FOUR-DIMENSIONAL NONLINEAR GAUGE THEORIES
Authors: BIZDADEA C. , CIOROIANU E. M. , SALIU S. O.
Published: July 2002

Consistent couplings among a set of scalar fields, two types of one-forms and a system of two-forms are investigated in the light of the Hamiltonian BRST cohomology, giving a four-dimensional nonlinear gauge theory. The emerging interactions deform the first-class constraints, the Hamiltonian gauge algebra, as well as the reducibility relations.
COSMOLOGICAL EVOLUTION IN A TYPE-0 STRING THEORY
Authors: DIAMANDIS G. A. , GEORGALAS B. C. , MAVROMATOS N. E. , PAPANTONOPOULOS E. , PAPPA I.
Published: July 2002

We study the cosmological evolution of a type-0 string theory by employing non-criticality, which may be induced by fluctuations of the D3 brane worlds. We check the consistency of the approach to [Formula: see text] in the corresponding σ-model. The ten-dimensional theory is reduced to an effective four-dimensional model, with only time dependent fields. We show that the four-dimensional universe has an inflationary phase and graceful exit from it, while the other extra dimensions are stabilized to a constant value, with the fifth dimension much larger than the others. We pay particular attention to demonstrating the role of tachyonic matter in inducing these features. The universe asymptotes, for large times, to a nonaccelerating linearly-expanding universe with a time-dependent dilaton and a relaxing to zero vacuum energy a lá quintessence. Our perturbative string solution appears to have initial singularities (Big Bang type), which however, we believe, may be lifted in a nonperturbative way, and they do not represent true singularities of the string theory.
PERTURBATIVE ANALYSIS OF THE SEIBERG–WITTEN MAP
Authors: BICHL A. A. , GRIMSTRUP J. M. , POPP L. , SCHWEDA M. , WULKENHAAR R.
Published: July 2002

We investigate the quantization of the θ-expanded noncommutative U(1) Yang–Mills action, obtained via the Seiberg–Witten map. The one-loop self-energy correction is gauge-independent. In a further paper, hep-th/0104097, we have shown that the loop correction may be renormalized via an unphysical field redefinition.