bluuebunny/crossref_metadata_2025 huggingface dataset:
Ancient hydrocarbon seeps from the Mesozoic convergent margin of California: carbonate geochemistry, fluids and palaeoenvironments
Authors: Campbell K. A. , Farmer J. D. , Des Marais D.
Published: March 2003

More than a dozen hydrocarbon seep‐carbonate occurrences in late Jurassic to late Cretaceous forearc and accretionary prism strata, western California, accumulated in turbidite/fault‐hosted or serpentine diapir‐related settings. Three sites, Paskenta, Cold Fork of Cottonwood Creek and Wilbur Springs, were analyzed for their petrographic, geochemical and palaeoecological attributes, and each showed a three‐stage development that recorded the evolution of fluids through reducing–oxidizing–reducing conditions. The first stage constituted diffusive, reduced fluid seepage (CH4, H2S) through seafloor sediments, as indicated by Fe‐rich detrital micrite, corroded surfaces encrusted with framboidal pyrite, anhedral yellow calcite and negative cement stable isotopic signatures (δ13C as low as −35.5‰ PDB; δ18O as low as −10.8‰ PDB). Mega‐invertebrates, adapted to reduced conditions and/or bacterial chemosymbiosis, colonized the sites during this earliest period of fluid seepage. A second, early stage of centralized venting at the seafloor followed, which was coincident with hydrocarbon migration, as evidenced by nonluminescent fibrous cements with δ13C values as low as −43.7‰ PDB, elevated δ18O (up to +2.3‰ PDB), petroleum inclusions, marine borings and lack of pyrite. Throughout these early phases of hydrocarbon seepage, microbial sediments were preserved as layered and clotted, nondetrital micrites. A final late‐stage of development marked a return to reducing conditions during burial diagenesis, as implied by pore‐associated Mn‐rich cement phases with bright cathodoluminescent patterns, and negative δ18O signatures (as low as −14‰ PDB). These recurring patterns among sites highlight similarities in the hydrogeological evolution of the Mesozoic convergent margin of California, which influenced local geochemical conditions and organism responses. A comparison of stable carbon and oxygen isotopic data for 33 globally distributed seep‐carbonates, ranging in age from Devonian to Recent, delineated three groupings that reflect variable fluid input, different tectono‐sedimentary regimes and time–temperature‐dependent burial diagenesis.
Fluidized sandstone intrusions as an indicator of Paleostress orientation, Santa Cruz, California
Authors: Boehm A. , Moore J. C.
Published: March 2003

The late Miocene sandstone intrusions of northern Santa Cruz County, California, are the largest subaerial exposures of clastic intrusions on earth. The intrusions are sourced from a sandstone, underlying mudstone, accumulated in an outer shelf to upper slope environment. Dikes are the most frequent intrusion type, reach the greatest thickness and tend to strike north‐east and dip steeply. One giant dike is more than 150 m wide. Sills are least frequent, locally > 8 m thick and have no clear preferred geographical distribution. Clustered intrusions are commonly < 10 cm thick and mostly composed of dikes of various attitudes. The majority of the intrusions probably were injected shallowly as some extrude onto the seafloor. The local seafloor extrusion also indicates injection during the deposition of the Santa Cruz Mudstone (7–9 Ma). The intrusions are concentrated at the basin margin. Fluid pressure at the centre of the basin and perhaps hydrocarbons were communicated to the basin margin through the then sand, causing fluid overpressures that contributed to the fluidization and intrusion into the overlying mudstone.

Primarily north‐east‐striking, steeply dipping dikes and secondarily, shallowly dipping sills are most significant in terms of regional connectivity of intrusions and physical dilation of the formation. The orientation of the dikes and sills indicates a regional stress field with a horizontal NE–SW maximum and a NW–SE minimum compressive direction. The simultaneous development of dikes and sills suggests similar magnitudes of the minimum and intermediate principal stresses. Preferential weakness along bedding contributed to the development of sills. Palaeomagnetic data indicate no significant block rotation around a vertical axis. The maximum principal stress direction indicated by the intrusions is about 55° to the San Gregorio Fault and about 70° to the San Andreas Fault during the late Miocene. This stress field is similar to the modern stress field and suggests moderate fault weakness.
Fracture‐fill calcite as a record of microbial methanogenesis and fluid migration: a case study from the Devonian Antrim Shale, Michigan Basin
Authors: Budai J. M. , Martini A. M. , Walter L. M. , Ku T. C. W.
Published: March 2003

The Devonian Antrim Shale is an organic‐rich, naturally fractured black shale in the Michigan Basin that serves as both a source and reservoir for natural gas. A well‐developed network of major, through‐going vertical fractures controls reservoir‐scale permeability in the Antrim Shale. Many fractures are open, but some are partially sealed by calcite cements that retain isotopic evidence of widespread microbial methanogenesis. Fracture filling calcite displays an unusually broad spectrum of δ13C values (+34 to −41‰ PDB), suggesting that both aerobic and anaerobic bacterial processes were active in the reservoir. Calcites with high δ13C values (>+15‰) record cementation of fractures from dissolved inorganic carbon (DIC) generated during bacterial methanogenesis. Calcites with low δ13C values (<−32‰) are solely associated with outcrop samples and record methane oxidation during cement precipitation. Fracture‐fill calcite with δ13C values between −10 and −30‰ can be attributed to variable organic matter oxidation pathways, methane oxidation, and carbonate rock buffering. Identification of13C‐rich calcite provides unambiguous evidence of biogenic methane generation and may be used to identify gas deposits in other sedimentary basins.

It is likely that repeated glacial advances and retreats exposed the Antrim Shale at the basin margin, enhanced meteoric recharge into the shallow part of the fractured reservoir, and initiated multiple episodes of bacterial methanogenesis and methanotrophic activity that were recorded in fracture‐fill cements. The δ18O values in both formation waters and calcite cements increase with depth in the basin (−12 to −4‰ SMOW, and +21 to +27‰ PDB, respectively). Most fracture‐fill cements from outcrop samples have δ13C values between −41 and −15‰ PDB. In contrast, most cement in cores have δ13C values between +15 and +34‰ PDB. Radiocarbon and230Th dating of fracture‐fill calcite indicates that the calcite formed between 33 and 390 ka, well within the Pleistocene Epoch.
Equations of state for basin geofluids: algorithm review and intercomparison for brines
Authors: Adams J. J. , Bachu S.
Published: March 2003

Physical properties of formation waters in sedimentary basins can vary by more than 25% for density and by one order of magnitude for viscosity. Density differences may enhance or retard flow driven by other mechanisms and can initiate buoyancy‐driven flow. For a given driving force, the flow rate and injectivity depend on viscosity and permeability. Thus, variations in the density and viscosity of formation waters may have or had a significant effect on the flow pattern in a sedimentary basin, with consequences for various basin processes. Therefore, it is critical to correctly estimate water properties at formation conditions for proper representation and interpretation of present flow systems, and for numerical simulations of basin evolution, hydrocarbon migration, ore genesis, and fate of injected fluids in sedimentary basins. Algorithms published over the years to calculate water density and viscosity as a function of temperature, pressure and salinity are based on empirical fitting of laboratory‐measured properties of predominantly NaCl solutions, but also field brines. A review and comparison of various algorithms are presented here, both in terms of applicability range and estimates of density and viscosity. The paucity of measured formation‐water properties at in situ conditions hinders a definitive conclusion regarding the validity of any of these algorithms. However, the comparison indicates the versatility of the various algorithms in various ranges of conditions found in sedimentary basins. The applicability of these algorithms to the density of formation waters in the Alberta Basin is also examined using a high‐quality database of 4854 water analyses. Consideration is also given to the percentage of cations that are heavier than Na in the waters.
Infiltration of basinal fluids into high‐grade basement, South Norway: sources and behaviour of waters and brines
Authors: Gleeson S. A. , Yardley B. W. D , Munz I. A. , Boyce A. J.
Published: March 2003

Quartz veins hosted by the high‐grade crystalline rocks of the Modum complex, Southern Norway, formed when basinal fluids from an overlying Palaeozoic foreland basin infiltrated the basement at temperatures of c. 220°C (higher in the southernmost part of the area). This infiltration resulted in the formation of veins containing both two‐phase and halite‐bearing aqueous fluid inclusions, sometimes with bitumen and hydrocarbon inclusions.

Microthermometric results demonstrate a very wide range of salinities of aqueous fluids preserved in these veins, ranging from c. 0 to 40 wt% NaCl equivalent. The range in homogenization temperatures is also very large (99–322°C for the entire dataset) and shows little or no correlation with salinity.

A combination of aqueous fluid microthermometry, halogen geochemistry and oxygen isotope studies suggest that fluids from a range of separate aquifers were responsible for the quartz growth, but all have chemistries comparable to sedimentary formation waters. The bulk of the quartz grew from relatively low δ18O fluids derived directly from the basin or equilibrated in the upper part of the basement (T < 200°C). Nevertheless, some fluids acquired higher salinities due to deep wall‐rock hydration reactions leading to salt saturation at high temperatures (>300°C).

The range in fluid inclusion homogenization temperatures and densities, combined with estimates of the ambient temperature of the basement rocks suggests that at different times veins acted as conduits for influx of both hotter and colder fluids, as well as experiencing fluctuations in fluid pressure. This is interpreted to reflect episodic flow linked to seismicity, with hotter dry basement rocks acting as a sink for cooler fluids from the overlying basin, while detailed flow paths reflected local effects of opening and closing of individual fractures as well as reaction with wall rocks. Thermal considerations suggest that the duration of some flow events was very short, possibly in the order of days. As a result of the complex pattern of fracturing and flow in the Modum basement, it was possible for shallow fluids to penetrate basement rocks at significantly higher temperatures, and this demonstrates the potential for hydrolytic weakening of continental crust by sedimentary fluids.
Creating new product concepts for foodservice – the role of conjoint measurement to identify promising product features
Authors: Moskowitz Howard
Published: March 2003

In the early stage of product development, the marketer and developer have many options available to them. This paper presents an overview to conjoint measurement, one approach to identifying the best of those options, and determining the customer‐relevant impact of each option. The paper explains how conjoint analysis fits into the emerging need for customer knowledge, and into the goal of fact‐based decision making. The paper tells how to conceptualize, execute, analyze and use the conjoint measurement technique for a burger product.
To everything there was a season: deconstructing UK food availability
Authors: Colquhoun Anne , Lyon Phil
Published: March 2003

For a considerable period of time, the UK has had a largely inflexible relationship between the seasons and the availability of many foods. Plants, with their constituent fruits, foliage and roots, provide numerous examples of seasonality in diet. In this, both plant and seasonal meat/fish variability, gives a cadence to the year as well as the potential for problems of glut and famine. Historically, at one extreme, the problem has been to preserve excesses to avoid starvation when food supply is predictably problematic. As an adjunct, people were also able to extend the pleasures of particular foods for a greater part of the year. Now, at the start of a new millennium, the effectiveness of food preservation and distribution techniques is such that most food commodities are available most of the time. In this paper, we map the progress of attempts to ensure food security and ask, by reference to food availability in the UK, if this has not been at the expense of novelty and the appreciation of seasonality.
Survival of Clostridium botulinum in hot‐fill meals
Authors: Rodgers Svetlana
Published: March 2003

Sous‐vide technology poses a risk of botulism. Twenty‐six catering and retail cook‐chill meals were challenged with non‐proteolytic Clostridium botulinum (103 spores/g) and incubated for 10 days at 10 °C. C. botulinum populations were enumerated on salicin tryptic soy agar and background microflora – on plate count agar. Botulinal toxin was detected using the enzyme‐linked immunoassay. Only ten of the products supported the active growth of this pathogen. C. botulinum populations were static in another ten products which had a low pH except for two vegetable‐based soups. In the remaining six products, C. botulinum populations reduced to undetectable levels. Although the predictive models described the general growth pattern of C. botulinum in the products supporting the active growth and the products with low pH values, they did not predict the spontaneous decline of this pathogen and the static populations in high pH vegetable soups.
Population dynamics of the lichen genus Bulbothrix Hale as potential bioindicators of ‘time‐since‐last‐fire’ in the cerrado of the Distrito Federal, central Brazil
Authors: Mistry Jayalaxshmi
Published: March 2003

This paper investigates the potential use of the corticolous lichen genus Bulbothrix Hale as a bioindicator of ‘time‐since‐last‐fire’ in the cerrado (savannas) of central Brazil. Work was carried out at the Reserva Ecológica do IBGE and the Jardim Botãnico de Brasilia, 33 km outside Brasilia D.F., in plots of cerrado denso with known fire histories within the ‘Fire Project’ area. Measurements of abundance and thallus size were taken of all Bulbothrix individuals encountered up to 2 m on the trunks of three phorophyte species. The results show that abundances and thalli sizes of the Bulbothrix populations can be correlated with the ‘time‐since‐last‐fire’ that had occurred in each of the plots. This study shows that is is possible to use characteristics of specific lichen populations as bioindicators of fire history.
The history, distribution and rate of spread of the invasive alien plant, bridal creeper, Asparagus asparagoides (L.) Wight, as determined from a questionnaire survey of landholders in south‐western Australia
Authors: Stansbury C. D. , Scott J. K.
Published: March 2003

The distribution and rate of spread of the introduced weed bridal creeper, Asparagus asparagoides (L.) Wight, were calculated from the results of a questionnaire that was distributed to landholders in the south‐west of Western Australia. The weed was associated with regions that receive more than 350 mm of annual rainfall. There was a weak association between properties that had a longer history of disturbance through clearing of native vegetation and the presence of A. asparagoides. On a local scale, the questionnaire indicated that the rate of spread of A. asparagoides peaked at 0.6 m/yr of radial spread for patches of 10 m2. The rate of spread of A. asparagoides on a regional scale was calculated as 0.09 postcode regions per year. While 50% of respondents indicated that they attempted to control the weed, only 20% of land managers on neighbouring properties (usually roadside reserves) were involved in some type of weed control. The level of weed control also influenced rates of spread calculated for weed patches for the two groups. Asparagus asparagoides was not ranked highly as a weed by landholders, whereas government officials surveyed considered it the most important environmental weed.
Genic diversity, genetic structure, and biogeography of Pinus sabiniana Dougl.
Authors: Ledig F. Thomas
Published: March 2003

Pinus sabiniana Dougl. (grey pine) forms savanna forests in the foothills surrounding California's Great Central Valley. However, its fossil record, which dates from the late Miocene through the Pliocene and Pleistocene, is found exclusively in southern California, south of the species’ present range. A total of twenty‐nine isozyme loci, representing eighteen enzyme systems, was assayed to analyse the genetic structure in eight populations of grey pine and attempt to track its migration history from southern to northern California. Expected heterozygosity in the two southernmost samples was 0.128 and 0.150, and heterozygosity tended to decrease with increasing latitude, suggesting the loss of diversity as grey pine dispersed northward. However, genetic distances between populations were very small, even on opposite sides of the treeless Great Central Valley; and estimated time since divergence was 900 to 9000 years at a maximum. Wright's FST, the proportion of total genetic diversity among populations, was only 0.057, which is similar to values found in many conifers with continuous distributions. Nm, the number of migrants among populations per generation, was 4.1 to 6.7, depending on estimator, and indicates that gene flow is extensive, or was so in the recent past. In every population, observed heterozygosity was less than expected heterozygosity, and the fixation index, FIS, for the progeny was 0.128, which indicates a fairly high rate of inbreeding. The genetic similarity of disjunct populations, in combination with paleogeographic and paleoclimatic evidence, suggests that grey pine formed a continuous population throughout the Great Central Valley, perhaps between 12,000 and 8000 yrs
BP. Its range became fragmented during the Xerothermic, when it ascended into the foothills. Gaps in its range correlate with late Pleistocene–early Holocene lakes in adjacent basins and with the Sacramento–San Joaquin Delta.
The taxonomic distribution of rare and common species among families in the vascular plant flora of Fennoscandia
Authors: Grytnes John Arvid , Birks H. J. B. , Peglar Sylvia M.
Published: March 2003

Many plant traits are not randomly distributed among families. The question considered here is ‘are rarity and commonness of vascular plants in Fennoscandia randomly distributed among families?’ If more rare or more common species are found within a family, this may give some initial indications about which traits may predict rarity and commonness of species. A species was defined as rare or common based on its abundance and on the number of grid squares it occupies. 1521 naturally occurring species in 229 75×75 km grid squares were used. Permutation tests were performed to assess statistically if rarity and commonness are randomly distributed among families. Several families can be identified as having more rare or more common species than would be expected under a random allocation model. However, there are little deviations from what would be expected if rarity and commonness were randomly distributed among families in the whole Fennoscandian flora. It is proposed that the arbitrary geographical limits of the study area may account for the lack of any clear patterns of rarity and commonness among and between families.
How localized are the distributions of Australian scarabs (Coleoptera, Scarabaeoidea)?
Authors: Allsopp P. G.
Published: March 2003

The degree of localization in the distribution of Australian scarabaeine (320 spp.), aphodiine (160 spp.), geotrupid (166 spp.) and dynastine (182 spp.) scarabs is analysed. Localization differs among these groups, appearing to increase marginally from the Dynastinae, to the Aphodiinae, to the Scarabaeinae, to the Geotrupidae, but with significant differences within groups, e.g. the scarabaeine tribes Onthophagini and Scarabaeini. However, the Australian fauna lacks the high proportion of widespread species characteristic of the West Palaearctic Scarabaeinae, Aphodiinae and Geotrupidae. This difference reflects the different ecological histories of the two regions.
Track analysis and conservation priorities in the cloud forests of Hidalgo, Mexico
Authors: Vega Isolda Luna , Ayala Othón Alcántara , Morrone JuaN. J. , Organista David Espinosa
Published: March 2003

Abstract . A track analysis based on the distributional patterns of 967 species of vascular plant taxa (gymnosperms, angiosperms and pteridophytes) was performed to assess conservation priorities for cloud forests in the state of Hidalgo, Mexico, ranged in the municipalities of Chapulhuacán, Eloxochitlán, Molocotlán, Pisaflores, Tenango de Doria, Tlahuelompa and Tlanchinol, as well as five floristically equivalent areas in the states of Veracruz (Teocelo and Helechales), Tamaulipas (Gómez Farías), Morelos‐México (Ocuilan) and Oaxaca (Huautla de Jiménez). In order to detect generalized tracks we employed a new parsimony method, where clades (considered equivalent to generalized tracks) are defined forbidding homoplasy and acting like a compatibility algorithm. Several generalized tracks were found connecting these areas. Cloud forests of Chapulhuacán were connected according to three different generalized tracks and thus have a higher value, qualifying as a priority area for the conservation of cloud forests in the state of Hidalgo.
Climatic and spatial patterns of diversity in the serpentine plants of California
Authors: Harrison Susan , Viers Joshua H. , Quinn James F.
Published: March 2003

Abstract . The insular distribution of distinctive substrates, such as outcrops of serpentine rock, may either promote plant diversity by enhancing opportunities for speciation or reduce diversity by increasing rates of extinction. To examine the relationship between diversity and the spatial structure of habitats, we studied large‐scale patterns of diversity in the flora of serpentine in California. We used multiple linear regressions on geographical information system (GIS)‐derived data for 85 subregions of the state to analyse the climatic and spatial correlates of plant species richness. The diversity of plants endemic to serpentine declined from north to south and from the coast inland, in association with decreasing rainfall; the same trends were seen in the total flora, but the trends were stronger in serpentine endemics. Diversity of serpentine endemics increased with the area of serpentine and decreased with the mean isolation of serpentine patches in a subregion. The diversity of endemics was not correlated with the number of serpentine patches or their mean perimeter‐to‐area ratio. We conclude that patchiness in this terrestrial habitat does not appear to promote diversity, even at the large spatial scale associated with speciation and endemism.
The distribution and prevalence of sponges in relation to environmental gradients within a temperate sea lough: vertical cliff surfaces
Authors: Bell James J. , Barnes David K. A.
Published: March 2003

Abstract. The prevalence and distribution of sponges was surveyed on vertical cliff surfaces at Lough Hyne Marine Nature Reserve, Co. Cork, Ireland. The number of sponge species was recorded at 6‐metre depth intervals at four sites within Lough Hyne, and at one site on the adjacent Atlantic coastline to examine differences in abundance and zonation patterns. Sites ranged from an exposed turbulent regime to sheltered, sedimented environments. Individual species showed different distributions and prevalence between sites and with increasing depth. Greatest differences were observed between the most‐ and least‐disturbed sites. Distinct sponge zonation patterns were evident at all sites sampled. Twenty‐five species were considered dominant at all five sites with the remaining 48 species considered rare. Only four of the 25 most‐dominant species occurred at the site experiencing the most turbulent flow conditions, whereas 12 species were found at the site of unidirectional fast flow. At sites of moderate to slight water movement and high sedimentation, between 18 and 24 of the most dominant species were present. Encrusting forms constituted high proportions of sponge communities at all five sites sampled (although consisting of different species). At sites of turbulent and unidirectional fast flow massive forms also dominated whereas at the least turbulent sites, where sedimentation was high, arborescent sponges were abundant. Few species showed exclusive distribution to a single depth and site, but there was some degree of correlation between species distributions and abiotic factors such as sedimentation rate and flow regimes. Sponge distributions and densities are discussed with respect to the suitability of species’ morphologies to particular environments, intra‐specific and inter‐specific competition and physiological adaptations that enable them to survive in different habitats.
The effects of fire on ant communities in north‐western Patagonia: the importance of habitat structure and regional context
Authors: Farji‐Brener Alejandro G. , Corley J. C. , Bettinelli J.
Published: March 2003

Abstract.We investigated the effects of recent fires on the native ant communities in two habitats of north‐west Patagonia that differ in vegetation structural complexity. Using bait traps, we sampled ants in replicated scrub and steppe areas including paired burned and unburned sites. Fires significantly reduced plant cover and ant diversity only in scrub sites. The drop in diversity was due to (a) a reduction in the abundance of rare species associated with woody vegetation, and (b) an increase in the abundance of the dominant species, which thrive in more xeric microclimatic conditions. Consequently, ant assemblage structure of burned scrub approaches that of steppe sites. Our findings suggest that the effects of disturbances on ant assemblages depends both on habitat characteristics, which in turn determine the extent of the changes induced by the disturbance, and on the regional context of the ant fauna, which in turn determines the ability of the ants to deal with the post‐disturbance conditions.
Invasion of pollination networks on oceanic islands: importance of invader complexes and endemic super generalists
Authors: Olesen Jens M. , Eskildsen Louise I. , Venkatasamy Shadila
Published: March 2003

Abstract. The structure of pollination networks is described for two oceanic islands, the Azorean Flores and the Mauritian Ile aux Aigrettes. At each island site, all interactions between endemic, non‐endemic native and introduced plants and pollinators were mapped. Linkage level, i.e. number of species interactions per species, was significantly higher for endemic species than for non‐endemic native and introduced species. Linkage levels of the two latter categories were similar. Nine types of interaction may be recognized among endemic, non‐endemic native and introduced plants and pollinators. Similar types had similar frequencies in the two networks. Specifically, we looked for the presence of ‘invader complexes’ of mutualists, defined as groups of introduced species interacting more with each other than expected by chance and thus facilitating each other’s establishment. On both islands, observed frequencies of interactions between native (endemic and non‐endemic) and introduced pollinators and plants differed from random. Introduced pollinators and plants interacted less than expected by chance. Thus, the data did not support the existence of invader complexes. Instead, our study suggested that endemic super‐generalist species, i.e. pollinators or plant species with a very wide pollination niche, include new invaders in their set of food plants or pollinators and thereby improve establishment success of the invaders. Reviewing other studies, super generalists seem to be a widespread island phenomenon, i.e. island pollination networks include one or a few species with a very high generalization level compared to co‐occurring species. Low density of island species may lead to low interspecific competition, high abundance and ultimately wide niches and super generalization.
The impact of an invading alien grass (Agropyron cristatum) on species turnover in native prairie
Authors: Heidinga Lawrence , Wilson Scott D.
Published: March 2003

Abstract. Alien invasions typically reduce species richness of habitats, but few studies have examined their effects on species turnover, the difference in species composition between localities. Agropyron cristatum (L.) Gaertn. (crested wheat grass) has been planted on 6–10 million ha of North American prairie, and is invading native prairie. We studied the invasion of A. cristatum into native prairie by measuring species composition along a gradient from maximum to minimum A. cristatum abundance. As A. cristatum increased, the abundance of most common native species decreased, but one appeared to be unaffected (Bouteloua gracilis (H.B.K.) Lag.), and another (Poa sandbergii Vasey) increased. The effect of A. cristatum on species turnover was investigated by examining species–area curves for areas from 0.5 m2 to 8.0 m2. Species diversity was reduced by 35% at high A. cristatum abundances at all areas. A. cristatum reduced the intercept of the species–area curve, but not the slope, suggesting that A. cristatum affected species turnover proportionally in all areas and habitats. This unusual result may indicate a homogeneous environment where species are distributed randomly. A. cristatum produced almost twice as many seeds as all native grasses combined. The number of seeds collected of native grasses and A. cristatum was highly correlated with the number of seed heads immediately nearby, but not with transect position. This suggests most seeds were dispersed over distances less than 5 m. In sum, the invasion of native prairie by A. cristatum might be related to high rates of seed production, and has the effect of decreasing species turnover by reducing the intercept of the species–area curve.
Are there predictable clines in plant–pollinator interactions along altitudinal gradients? The example ofCytisus scoparius(L.) Link in the Sierra de Guadarrama (Central Spain)
Authors: Malo Juan E. , Baonza Jorge
Published: March 2003

Abstract.We analyse the hypothesis that predictable gradients occur in plant–pollinator interactions along altitudinal gradients due to thermal constraints on insect body size and floral traits being selected for by pollinators. Pollinators’ size should follow Bergmann's rule in mountains (larger body size at higher altitudes) and selection should, in turn, lead to larger flower size at higher altitudes. The study focuses on the flower and pollinator size variation in 11Cytisus scopariuspopulations located between 680 and 1300 m a.s.l., and on the relationship between flower size and pollination success of plants in each population. Significant differences among populations were found in flower size, pollinator size and fruiting success (anova,P < 0.001 in all cases). Regression models show that (i) pollinator size increases significantly with altitude, (ii) a parallel quadratic increase in flower size and (iii) a quadratic decrease in pollination success with altitude. Moreover, there is a tendency of plants with smaller flowers in each population to have a higher percentage of flowers initiating development into fruits (ancova,P < 0.05). All these observations support the presence of the predicted gradient in the studied species and they suggest the possibility of it to be somewhat common among plants that occupy large altitudinal ranges due to the simple basis on which it could be rooted.
Alien predators and amphibian declines: review of two decades of science and the transition to conservation
Authors: Kats Lee B. , Ferrer Ryan P.
Published: March 2003

Over the last two decades, numerous studies have shown that alien predators contributed to amphibian population declines. Both experimental studies and correlative field surveys implicated alien species of fish, bullfrogs and crayfish as major contributors to amphibian population decline, and in some instances local extinction. Additional studies have demonstrated that alien predators also caused long‐term changes in aquatic communities. Recent studies have examined the feasibility of removing alien predators, and provide some evidence that amphibian populations can recover. Applying information gained from past studies to the recovery of amphibian populations will be the challenge of future studies. International, national and local policies that regulate alien predators should be based largely on the body of scientific evidence already in the literature. Scientists need to be more involved with policy‐makers to most effectively change laws that regulate alien predators.
Usage of the internet pharmacology resources among European pharmacologists: a preliminary investigation
Authors: Šalković‐Petrišić Melita , Mrzljak Anna , Lacković Zdravko
Published: March 2003

The Internet is becoming an ever more important source of information in pharmacology and medicine. Little is known, however, about which Internet pharmacology resources are actually used by the pharmacologists – and to what extent – and how they estimate the Internet information quality and evaluation. This pilot study used an anonymous questionnaire, distributed among 250 mostly European (220/250) pharmacologists from 30 European countries attending The 2nd European Congress of Pharmacology, held in Budapest, Hungary, in 1999. According to study results, 93% of all participants use the Internet pharmacology resources: 56%, 35% and 9% of them on a daily, weekly and monthly basis, respectively. Among 56 pharmacological/medical free online databases offered, the general scientific databases were found to greatly prevail (Pub Med 60%, Evaluated MEDLINE 37%, Internet Grateful Med 29%, etc.), while drug monographs or toxicological databases were less used [e.g. ECDIN, RxList, National Toxicology Programme (NTP) < 10%]. Some 80% of the participants estimated the quality of the pharmacological information on the Internet as good or very good, while 20% thought the quality should be improved. Also, 35% of participants felt the need for improvement of the Internet pharmacological information evaluation, which should be the goal of pharmacology professional.
Effect of centrally administered prolactin on gastric and duodenal ulcers in rats
Authors: Asad M. , Shewade D. G. , Koumaravelou K. , Abraham B. K. , Vasu S. , Ramaswamy S.
Published: March 2003

The effect of centrally administered prolactin on gastric acid secretion and experimentally‐induced gastric and duodenal ulcers was studied. The acute gastric ulcer models used were pylorus ligation, indomethacin‐induced and ethanol‐induced gastric ulcers. Chronic gastric ulcers were induced using acetic acid and duodenal ulcers by cysteamine hydrochloride. In pylorus ligated rats, prolactin (1 μg/kg icv) produced 45% increase in gastric content volume, significant increase in free acidity (P < 0.001), total acidity (P < 0.001) and ulcer index (P < 0.001). It did not show any significant effect on ethanol‐induced and indomethacin‐induced gastric ulcers. Prolactin increased the ulcer index (P < 0.001) and ulcer score (P < 0.05) in acetic acid‐induced chronic gastric ulcers. It also increased ulcer area (P < 0.05) in cysteamine‐induced duodenal ulcers. Therefore, the proulcerogenic activity of prolactin was due to its gastric hypersecretory effect.
Role of endothelium in adenosine receptor‐mediated vasorelaxation in hypertensive rats
Authors: Fahim Mohammad , Hussain Tahir , Mustafa S. Jamal
Published: March 2003

The present study was designed to investigate the role of endothelium derived relaxing factor nitric oxide (NO) in adenosine A2 receptor mediated vasorelaxation in normotensive (WKY) and hypertensive (SHR) rat aortic ring preparations. Adenosine analogues, 2‐chloroadenosine (CAD) and 5‐ethylcarboxamidoadenosine (NECA) produced concentration‐dependent (10−9–10−4 M) relaxation in phenylephrine (1 × 10–6 M) precontracted vascular rings, which was significantly shifted to the right in SHR compared to WKY rats. Endothelium removal attenuated CAD and NECA relaxation responses in both SHR and WKY and abolished the difference in relaxation between SHR and WKY vascular tissues. The relaxation response to CAD was antagonised by adenosine A2 receptor antagonist, 8‐sulfophenyltheophylline (8‐SPT, 50 × 10–6 M). The antagonism by 8‐SPT was lower in SHR as compared to WKY tissues. L‐monomethylarginine (L‐LMMA) (30 × 10–6 M) significantly shifted the CAD relaxation to the right, which was reversed by the addition of L‐arginine (100 × 10–6 M) in both SHR and WKY rats. However, the rightward shift by L‐NMMA was smaller in SHR compared to WKY vascular tissues. Vasorelaxation response to acetylcholine (1 × 10–6 M) was significantly inhibited (50%) in SHR rings compared to WKY. The relaxation produced by sodium nitroprusside (10−9–10−5 M) in endothelium‐intact and ‐denuded aortic rings showed no difference between SHR and WKY. Isoproterenol produced concentration‐dependent (10−9–10−5 M) relaxation, which was shifted to the right in SHR compared to WKY rings with an intact endothelium, while the removal of endothelium abolished the difference in the response between SHR and WKY. The results suggest: (i) adenosine A2 receptors mediate vasorelaxation in part through endothelium possibly by releasing nitric oxide (NO); (ii) the impairment of endothelium may be one of the factors for the attenuation of adenosine receptor and receptor‐mediated responses in SHR.
Metabolism of methoxymorpholino‐doxorubicin in rat, dog and monkey liver microsomes: comparison with human microsomes
Authors: Beulz‐Riche Dominique , Robert Jacques , Menard Christophe , Ratanasavanh Damrong
Published: March 2003

The morpholino anthracycline, methoxymorpholino‐doxorubicin (MMDx) is a novel anticancer agent. The metabolism of this highly lipophilic doxorubicin analogue is not fully elucidated. MMDx is metabolically activated in vivo, resulting in an 80‐fold increase in potency over the parent drug. In this study, MMDx in vitro metabolism was compared in rat, dog, monkey and human liver microsomes.

When microsomal fractions were incubated with MMDx, 6–8 metabolites were formed depending on the species and on the substrate concentrations. Among these eight metabolites, three comigrated with authentic standards, namely MMDx‐ol, PNU156686 and PNU159682, and the five others are in the process of being characterized. Quantitatively, monkey and human metabolize MMDx with a higher rate than rat and dog. Qualitatively, MMDx metabolic profile in dog microsomes was different from the three other species. MMDx‐ol was predominant in dog and only minor in other species.

In conclusion, MMDx metabolism was species‐different. Rat and monkey liver microsomes may be used as models to study MMDx metabolism in humans. Dog liver microsomes may be a good model for studying the formation of MMDx‐ol.
Do endogenous opioids contribute to the bradycardia of rats with obstructive cholestasis?
Authors: Gaskari Seyed Ali , Mani Ali Reza , Ejtemaei‐Mehr Shahram , Namiranian Khodadad , Homayoun Houman , Ahmadi Hossein , Dehpour Ahmad Reza
Published: March 2003

Endogenous opioids have nitric oxide (NO)‐dependent cardiovascular actions. In the light of biological evidence of accumulation of endogenous opioids in cholestasis and also existence of NO‐dependent bradycardia in cholestatic subjects, this study was carried out to evaluate the role of endogenous opioids in the generation of bradycardia in a rat model of cholstasis. Male Sprague‐Dawley rats were used to induce cholestasis by surgical ligation of the bile duct, with sham‐operated animals serving as a control. The animals were divided into six groups which received naltrexone [20 mg/kg/day, subcutaneously (s.c.)], NG‐l‐nitro‐arginine methyl ester (L‐NAME, 3 mg/kg/day, s.c.), aminoguanidine (200 mg/kg/day, s.c.), l‐arginine (200 mg/kg/day, s.c.), naltrexone + L‐NAME (20 and 3 mg/kg/day, s.c) or saline. One week after the operation, a lead II electrocardiogram (ECG) was recorded and the spontaneously beating atria of the animals were then isolated and the chronotropic responses to epinephrine evaluated. The plasma l‐nitro‐tyrosine level and alanine amino transferase and alkaline phosphatase activities were also measured. The heart rate of cholestatic animals was significantly lower than that of control rats in vivo and this bradycardia was corrected with daily adminstration of naltrexone or L‐NAME. The basal spontaneous beating rate of atria in cholestatic animals was not significantly different from that of sham‐operated animals in vitro. Cholestasis induced a significant decrease in the chronotropic effect of epinephrine. This effect was corrected by daily injection of naltrexone or L‐NAME, or concurrent administration of naltrexone + L‐NAME, and was not corrected by aminoguanidine. l‐arginine had an equivalent effect to L‐NAME and increased the chronotropic effect of epinephrine in cholestatic rats but not in control animals. Bile duct ligation increased the plasma activity of liver enzymes as well as the level of l‐nitro‐tyrosine. l‐arginine and naltrexone treatment significantly decreased the elevation of liver enzymes in bile duct‐ligated rats. Pretreatment of cholestatic animals with naltrexone or L‐NAME decreased the plasma l‐nitro‐tyrosine level. The results suggest that either prevention of NO overproduction or protection against liver damage is responsible for recovery of bradycardia after naltrexone administration.
Safety pharmacology and risk assessment
Authors: Kinter Lewis B. , Valentin Jean‐Pierre
Published: March 2003

Evaluation of experimental drugs in animals for effects on critical organ systems allows identification of functional signals of efficacy and safety that can be subsequently monitored in human clinical trials. The International Conference on Harmonization (ICH), `Guidelines on Safety Pharmacology', finalized in 2000, defined critical organ systems (cardiovascular, respiratory and central nervous system) and functions to be evaluated, and points to consider for study design and conduct. The new Safety Pharmacology guidelines recognise that while in vitro studies of molecular targets (enzymes, receptors, ion channels, etc.) suggest mechanisms by which chemicals might impact organisms, organ functions are complex, integrative, and most usefully evaluated in their totality, in intact and ideally unanesthetized animal models.

Signals identified from safety pharmacology studies are candidates for biomarkers, which when established/validated, can enhance cross‐species‐based risk assessments and risk management in clinical trials. This review will briefly trace the origins of modern safety pharmacology and discuss practical issues related to the identification and application of signals generated from safety pharmacology studies. The QT interval from the electrocardiogram is currently the `most validated' of those signals (`biomarkers') generated from safety pharmacology studies and is presented as an example of the utility and the difficulties faced by safety pharmacologists attempting to predict risk in humans based upon physiological measurements conducted in animal studies.
FOSIDIAL: a randomised placebo controlled trial of the effects of fosinopril on cardiovascular morbidity and mortality in haemodialysis patients. Study design and patients' baseline characteristics
Authors: Zannad Faiez , Kessler Michèle , Grünfeld Jean Pierre , Thuilliez Christian ,   FOSIDIAL Investigators
Published: March 2003

The prevalence of end stage renal disease (ESRD) is growing in western countries. Patients with ESRD are more frequently elderly and diabetic and are exposed to very high cardiovascular morbidity and mortality. The main aim of the FOSIDIAL study is to assess the efficacy and safety of fosinopril, an angiotensin converting enzyme (ACE) inhibitor, in reducing the mortality and cardiovascular events in haemodialysis patients presenting with left ventricular hypertrophy. A total number of 397 patients are included in the study. They are aged 50–80 years (average 66.7 years) and have been undergoing haemodialysis for 4.8 years. All have left ventricular hypertrophy with cardiac mass index > 100 g/m2 in women and > 130 g/m2 in men, measured within 3 months prior to inclusion. Baseline cardiac mass index is 174 g/m2. After a 2 week placebo period, the patients are randomised into two groups receiving either fosinopril 5–20 mg/day, or a placebo for a duration of 24 months. The target dose is reached at the sixth, seventh or eighth week of treatment. Depending on tolerance, 300 patients reached the maximum recommended dose. Patients are subsequently assessed clinically every 3 months until the end of the study. The primary outcome is a composite endpoint of fatal and nonfatal major cardiovascular events. Secondary endpoints are individual cardiovascular events, event‐free survival, overall mortality and all‐cause hospitalisations. The trial began in October 1998. All patients were included by December 2000 and follow‐up is ongoing. The last visit for the last patient is scheduled for 30 December 2002. We report here on the study design and the baseline characteristics of the study population.
Internationalization of regulatory requirements
Authors: Juillet Y.
Published: March 2003

The aim of harmonisation of medicines regulatory requirements is to allow the patient quicker access to new drugs and to avoid animal and human duplications. Harmonisation in the European Union (EU) is now completed, and has led to the submission of one dossier in one language study leading to European marketing authorizations, thanks in particular to efficacy guidelines published at the European level. With the benefit of the European experience since 1989, more than 40 guidelines have been harmonised amongst the EU, Japan and the USA through the International Conference on Harmonisation (ICH). ICH is a unique process gathering regulators and industry experts from the three regions. Its activity is built on expertise and trust. The Common Technical Document (CTD), an agreed common format for application in the three regions, is a logical follow‐up to the ICH first phase harmonising the content of the dossier. The CTD final implementation in July 2003 will have considerable influence on the review process and on the exchange of information in the three regions.
Sleep attacks in Parkinson's disease induced by Entacapone, a COMT‐inhibitor
Authors: Santens Patrick
Published: March 2003

We present a patient who suffered from sleep attacks after starting entacapone in addition to levodopa. Entacapone, a catechol‐O‐methyl transferase inhibitor, alters the pharmacokinetics of levodopa, leading to increase of levodopa concentration in plasma and brain. This mechanism is suspected to be involved in the pathophysiology of sleep attacks in this case.