bluuebunny/crossref_metadata_2025_split huggingface dataset:
Understanding properly the `potential natural vegetation' concept
Authors: Loidi Javier , del Arco Marcelino , Pérez de Paz Pedro Luis , Asensi Alfredo , Díez Garretas Blanca , Costa Manuel , Díaz González Tomás , Fernández‐González Federico , Izco Jesús , Penas Ángel , Rivas‐Martínez Salvador , Sánchez‐Mata Daniel 
Published: May 2010

AbstractThis is a response to critical comments concerning the inappropriate use of the potential natural vegetation (PNV) concept made in a recent contribution to the Commentary section of this journal. We consider that the PNV concept has been misinterpreted. PNV has been used extensively in several European countries since the mid‐1950s and was never intended to be used to make a prediction of what vegetation would dominate in an area if human influence were removed. PNV maps express hypothetical assumptions of what corresponds to dominant or natural vegetation in each area. Remnants of the vegetation of the past provided by palaeopalynology and other disciplines provide valuable information for interpreting modern vegetation, but natural changes and anthropogenic influences operating over the last millennia have to be taken into account. Annex I of the Habitats Directive provides a balanced list of habitat types for implementing conservation policies within the European Union.
Fine‐scale determinants of butterfly species richness and composition in a mountain region
Authors: Illán Javier Gutiérrez , Gutiérrez David , Wilson Robert J. 
Published: May 2010

AbstractAim  Global patterns of species richness are often considered to depend primarily on climate. We aimed to determine how topography and land cover affect species richness and composition at finer scales.Location  Sierra de Guadarrama (central Iberian Peninsula).Methods  We sampled the butterfly fauna of 180 locations (89 in 2004, 91 in 2005) at 600–2300 m elevation in a region of 10800 km2. We recorded environmental variables at 100‐m resolution using GIS, and derived generalized linear models for species density (number of species per unit area) and expected richness (number of species standardized to number of individuals) based on variables of topoclimate (elevation and insolation) or land cover (vegetation type, geology and hydrology), or both (combined). We evaluated the models against independent data from the alternative study year. We also tested for differences in species composition among sites and years using constrained ordination (canonical correspondence analysis), and used variation partitioning analyses to quantify the independent and combined roles of topoclimate and land cover.Results  Topoclimatic, land cover and combined models were significantly related to observed species density and expected richness. Topoclimatic and combined models outperformed models based on land cover variables, showing a humped elevational diversity gradient. Both topoclimate and land cover made significant contributions to models of species composition.Main conclusions  Topoclimatic factors may dominate species richness patterns in regions with pronounced elevational gradients, as long as large areas of natural habitat remain. In contrast, both topoclimate and land cover may have important effects on species composition. Biodiversity conservation in mountainous regions therefore requires protection and management of natural habitats over a wide range of topoclimatic conditions, which may assist in facilitating range shifts and alleviating declines in species richness related to climate change.
Effects of sampling protocol on the shapes of species richness curves
Authors: Dengler Jürgen , Oldeland Jens 
Published: May 2010

AbstractAim  Scheiner (Journal of Biogeography, 2009, 36, 2005–2008) criticized several issues regarding the typology and analysis of species richness curves that were brought forward by Dengler (Journal of Biogeography, 2009, 36, 728–744). In order to test these two sets of views in greater detail, we used a simulation model of ecological communities to demonstrate the effects of different sampling schemes on the shapes of species richness curves and their extrapolation capability.Methods  We simulated five random communities with 100 species on a 64 × 64 grid using random fields. Then we sampled species–area relationships (SARs, contiguous plots) as well as species–sampling relationships (SSRs, non‐contiguous plots) from these communities, both for the full extent and the central quarter of the grid. Finally, we fitted different functions (power, quadratic power, logarithmic, Michaelis–Menten, Lomolino) to the obtained data and assessed their goodness‐of‐fit (Akaike weights) and their extrapolation capability (deviation of the predicted value from the true value).Results  We found that power functions gave the best fit for SARs, while for SSRs saturation functions performed better. Curves constructed from data of 322 grid cells gave reasonable extrapolations for 642 grid cells for SARs, irrespective of whether samples were gathered from the full extent or the centre only. By contrast, SSRs worked well for extrapolation only in the latter case.Main conclusions  SARs and SSRs have fundamentally different curve shapes. Both sampling strategies can be used for extrapolation of species richness to a target area, but only SARs allow for extrapolation to a larger area than that sampled. These results confirm a fundamental difference between SARs and area‐based SSRs and thus support their typological differentiation.
Functional composition controls invasion success in a California serpentine grassland
Authors: Hooper David U. , Dukes Jeffrey S. 
Published: May 2010

Summary1.Recent debates about the role of biotic resistance in controlling invasion success have focused on effects of species richness. However, functional composition could be a stronger control: species already in the community with similar functional traits to those of the invaders should have the greatest competitive effect on invaders. Still, experiments assessing effects of functional similarity have found contradictory results.2.We used experimental communities in a serpentine grassland in California, USA, to assess the extent to which functional composition and functional diversity influenced success of two different types of invading plants: early season annuals (E) and late‐season annuals (L) that have been previously shown to differ in patterns of resource acquisition.3.We seeded known quantities of seed of six different species (three in each functional group) into experimental plots containing established communities differing in functional composition and functional diversity. The experimental communities contained different combinations of E, L, perennial bunchgrass (P) and nitrogen‐fixer (N) functional groups, with functional diversity ranging from 0 to 4 groups. Each invading species was seeded into a separate quadrat within each plot to minimize competitive effects of invaders on each other. We measured both seedling and adult success of invaders for two full growing seasons to further understand mechanisms underlying biotic resistance.4.More functionally diverse communities were less invaded overall, as measured by the average success of individual invaders. However, assessment of invaders by functional groups was more informative: Es in the extant community suppressed E invaders the most, and Ls in the extant community suppressed L invaders the most.5.We observed a variety of interactions among extant functional groups in reducing invader success, including synergism, complementarity and ‘basement’ effects, where two or more groups negatively affected invaders, but combinations of groups were no more suppressive than single groups. The extant community influenced invaders more strongly through suppression of adult plant growth than through effects on seedling establishment.6.Synthesis.Contrary to predictions from neutral theory, these results indicate that niche overlap was an important component of biotic resistance in these experimental plant communities and summed up to significant effects of species richness.
Nitrogen uptake by Carex aquatilis during the winter–spring transition in a low Arctic wet meadow
Authors: Edwards Kate A. , Jefferies Robert L. 
Published: May 2010

Summary 1. Processes of decomposition occur year‐round in tundra ecosystems and respond quickly to seasonal changes. Characterizing the phenology of plant nutrient uptake in relation to these processes is essential to understanding the current and future productivity of Arctic ecosystems. 2. In wet sedge meadows located near Churchill, Manitoba, Canada, soil microbial biomass as well as inorganic and organic nutrient pools fluctuate seasonally, with late‐winter peaks followed by declines of these variables during the early stages of soil thaw; however, it is unknown if the dominant plant in this community takes up nitrogen when levels of this nutrient are high but soil temperatures are 0 °C or below. 3. Stable isotope tracing was utilized by injecting 15NH4Cl into soil cores and incubating for 1 or 8 days during spring thaw to determine the short‐term capacity for uptake and transport of inorganic nitrogen into Carex aquatilis (roots, shoots and rhizomes), moss and soil micro‐organisms during this transitional time of year. 4. During three 8‐day experimental trials in April and May 2007, C. aquatilis roots accumulated a substantial amount of the added nitrogen (33.5% increasing to 63.4%), when inorganic nitrogen was readily available in the soil, but declining. A smaller proportion of injected nitrogen was recovered from soil microbes (30% decreasing to 7%), and only trace amounts of injected 15N were measured in plant shoots, shoot bases, rhizomes and mosses (2% or less). 5. Synthesis. Shifting seasonal patterns in northern ecosystems resulting from climate change are likely to alter the progression of events that lead up to the summer growing season. A substantial pool of inorganic nitrogen resides temporarily in the soil at the end of winter, and we have shown here that plants are able to take up nitrogen at this time. Increases in the frequency and temperature highs of late‐winter warming events are likely to trigger early episodes of soil thaw, potentially reducing the capacity of plants to take up this large ephemeral supply of nitrogen in early spring.
Digital stain separation for histological images
Authors: TADROUS P.J. 
Published: May 2010

SummaryIt is often desirable to perform digital image analyses on sections prepared for human interpretation, e.g. nuclear chromatin texture analysis or three‐dimensional reconstructions using sections requiring human delineation of structures of interest. Unfortunately such analyses are often more effective using stains with less complex contrast. Here an automated selective ‘de‐staining’ method for digital images is presented. The method separates an image into its red, green and blue and hue, saturation and intensity components. A mask of stained tissue is prepared by automatic percentile thresholding. A single weighted inverted colour channel is then added to each of the three primary colour channels separately by an iterative algorithm that adjusts the weights to give minimum variance within the mask. The modified red, green and blue channels are then recombined. This method is automatic requiring no pre‐definition of stain colours or special hardware. The method is demonstrated to ‘de‐stain’ nuclei in haematoxylin and eosin (H&E) sections (and a separate haematoxylin image can be derived from this). An image of isolated brown reaction product is produced with immunoperoxidase preparations counterstained with haematoxylin. Furthermore trichrome (haematoxylin van Gieson, picrosirius red) and other common stains may be separated into their components with modifications of the same algorithm. Although other methods for colour separation do exist (e.g. spectral pathology and colour deconvolution) these require special apparatus or precise calibration and foreknowledge of pure dye colour spectra. The present method of digital stain separation is fully automatic with no such prerequisites.
3D structural analysis: sensitivity of Minkowski functionals
Authors: ARNS C.H. , KNACKSTEDT M.A. , MECKE K. 
Published: May 2010

SummaryThe Minkowski functionals, a family of statistical measures based on the Euler–Poincaré characteristic of n‐dimensional space, are the complete set of additive morphological measures and can be simply calculated from local contributions. As such, they have found a wide range of applications. We consider the effects of distortions (drift, noise and blurring) on the morphological properties of complex random models, representative of a wide range of structure. Such distortions arise experimentally in imaging techniques due to diffraction, absorption and sample drift. The question is asked, how critically these distortions effect image quality as measured by the Minkowski functionals. Defining a length scale based on the two‐point correlation function, we consider how distortion at different scales can lead to quantitative errors in morphological measures.
Characterization of dentine structure in three dimensions using FIB‐SEM
Authors: EARL J.S. , LEARY R.K. , PERRIN J.S. , BRYDSON R. , HARRINGTON J.P. , MARKOWITZ K. , MILNE S.J. 
Published: May 2010

SummaryAll biological tissues are three dimensional and contain structures that span a range of length scales from nanometres through to hundreds of millimetres. These are not ideally suited to current three‐dimensional characterization techniques such as X‐ray or transmission electron tomography. Such detailed morphological analysis is critical to understanding the structural features relevant to tissue function and designing therapeutic strategies intended to address structural deficiencies encountered in pathological states. We show that use of focused ion beam milling combined with scanning electron microscopy can provide three‐dimensional information at nanometre resolution from biologically relevant volumes of material, in this case dentine.
LR White sections as slot grid support films for transmission electron microscopy
Authors: VON RUHLAND C.J. , HOBOT J.A. 
Published: May 2010

SummaryThe utility of LR White sections as slot grid support films for the examination of thin resin‐embedded tissue sections by transmission electron microscopy was investigated and compared with traditional formvar‐carbon films. Throughout a variety of staining procedures, which involved the use of organic solvent, oxidizing agents, strong acid and prolonged incubation, LR White support films remained intact and the attached tissue sections remained adherent. By contrast, complete loss of formvar‐carbon support films occurred in 25% of preparations during routine staining with aqueous reagents. This loss increased to 62% following staining with either alcoholic or oxidizing and acidic stains, and to 66% following prolonged (immunohistochemical) staining. Tissue contrast, ultrastructural detail and immunohistochemical staining intensity were comparable between sections on the two types of support film. The use of LR White sections as support films for slot grids represents a quick, cheap, simple and robust alternative to traditional support films and, furthermore, requires no carbon coating
Photosynthetic responses of two eucalypts to industrial‐age changes in atmospheric [CO2] and temperature
Authors: GHANNOUM OULA , PHILLIPS NATHAN G. , SEARS MARIE A. , LOGAN BARRY A. , LEWIS JAMES D. , CONROY JANN P. , TISSUE DAVID T. 
Published: May 2010

ABSTRACTThe unabated rise in atmospheric [CO2] is associated with increased air temperature. Yet, few CO2‐enrichment studies have considered pre‐industrial [CO2] or warming. Consequently, we quantified the interactive effects of growth [CO2] and temperature on photosynthesis of faster‐growing Eucalyptus saligna and slower‐growing E. sideroxylon. Well‐watered and ‐fertilized tree seedlings were grown in a glasshouse at three atmospheric [CO2] (290, 400, and 650 µL L−1), and ambient (26/18 °C, day/night) and high (ambient + 4 °C) air temperature. Despite differences in growth rate, both eucalypts responded similarly to [CO2] and temperature treatments with few interactive effects. Light‐saturated photosynthesis (Asat) and light‐ and [CO2]‐saturated photosynthesis (Amax) increased by ∼50% and ∼10%, respectively, with each step‐increase in growth [CO2], underpinned by a corresponding 6–11% up‐regulation of maximal electron transport rate (Jmax). Maximal carboxylation rate (Vcmax) was not affected by growth [CO2]. Thermal photosynthetic acclimation occurred such that Asat and Amax were similar in ambient‐ and high‐temperature‐grown plants. At high temperature, the thermal optimum of Asat increased by 2–7 °C across [CO2] treatments. These results are the first to suggest that photosynthesis of well‐watered and ‐fertilized eucalypt seedlings will remain strongly responsive to increasing atmospheric [CO2] in a future, warmer climate.
Arabidopsis eIF5A3 influences growth and the response to osmotic and nutrient stress
Authors: MA FENGSHAN , LIU ZHONGDA , WANG TZANN‐WEI , HOPKINS MARIANNE T. , PETERSON CAROL A. , THOMPSON JOHN E. 
Published: May 2010

ABSTRACTAteIF5A3, one of three genes encoding eukaryotic translation initiation factor 5A (eIF5A) inArabidopsis thaliana, and corresponding genesPdeIF5A3fromPopulus deltoides(eastern cottonwood) andSleIF5A4fromSolanum lycopersicum(tomato) were constitutively over‐expressed inA. thaliana.The resultant transgenic plants exhibited enhanced vegetative and reproductive growth. Indeed, the increase in seed yield relative to empty vector controls for thePdeIF5A3over‐expressing plants ranged from 50% to 300% depending on the line. ThePdeIF5A3over‐expressing plants also exhibited enhanced fitness when exposed to osmotic and nutrient (N, P and K) stress. The spatial localization ofAteIF5A3 was visualized by confocal microscopy using transgenic plants expressingPAteIF5A3:GFP‐AteIF5A3. GFP fluorescence reflecting expression ofAteIF5A3 was detectable in the phloem, particularly companion cells, of roots, stems and leaves, in the epidermal cells of the root tip, in the columella cells of the root cap and in the chalazal tissue of fertilized ovules, which all play a pivotal role in nutrient or hormone translocation. Thus,AteIF5A3 appears to be involved in supporting growth and to play a regulatory role in the response of plants to sub‐lethal osmotic and nutrient stress.
The sucrose transporter HbSUT3 plays an active role in sucrose loading to laticifer and rubber productivity in exploited trees of Hevea brasiliensis (para rubber tree)
Authors: TANG CHAORONG , HUANG DEBAO , YANG JIANGHUA , LIU SHUJIN , SAKR SOULAÏMAN , LI HEPING , ZHOU YIHUA , QIN YUNXIA 
Published: May 2010

ABSTRACTEfficient sucrose loading in rubber‐producing cells (laticifer cells) is essential for retaining rubber productivity in Hevea brasiliensis, but the molecular mechanisms underlying the regulation of this process remain unknown. Here, we functionally characterized a putative Hevea SUT member, HbSUT3, mainly in samples from regularly exploited trees. When expressed in yeast, HbSUT3 encodes a functional sucrose transporter that exhibits high sucrose affinity with a Km value of 1.24 mm at pH 4.0, and possesses features typical of sucrose/H+ symporters. In planta, when compared to the expression of other Hevea SUT genes, HbSUT3 was found to be the predominant member expressed in the rubber‐containing cytoplasm (latex) of laticifers. The comparison of HbSUT3 expression among twelve Hevea tissues demonstrates a relatively tissue‐specific pattern, i.e. expression primarily in the latex and in female flowers. HbSUT3 expression is induced by the latex stimulator Ethrel (an ethylene generator), and relates to its yield‐stimulating effect. Tapping (the act of rubber harvesting) markedly increased the expression of HbSUT3, whereas wounding alone had little effect. Moreover, the expression of HbSUT3 was found to be positively correlated with latex yield. Taken together, our results provide evidence favouring the involvement of HbSUT3 in sucrose loading into laticifers and in rubber productivity.
Chert spheroids of the Monterey Formation, California (USA): early‐diagenetic structures of bedded siliceous deposits
Authors: BEHL RICHARD J. 
Published: May 2010

AbstractChert spheroids are distinctive, early‐diagenetic features that occur in bedded siliceous deposits spanning the Phanerozoic. These features are distinct in structure and genesis from similar, concentrically banded ‘wood‐grain’ or ‘onion‐skin’ chert nodules from carbonate successions. In the Miocene Monterey Formation of California (USA), chert spheroids are irregular, concentrically banded nodules, which formed by a unique version of brittle differential compaction that results from the contrasting physical properties of chert and diatomite. During shortening, there is brittle fracture of diatomite around, and horizontally away from, the convex surface of strain‐resistant chert nodules. Unlike most older siliceous deposits, the Monterey Formation still preserves all stages of silica diagenesis, thus retaining textural, mineralogical and geochemical features key to unravelling the origin of chert spheroids and other enigmatic chert structures. Chert spheroids found in opal‐A diatomite form individual nodules composed of alternating bands of impure opal‐CT chert and pure opal‐CT or chalcedony. With increased burial diagenesis, surrounding diatomite transforms to bedded porcelanite or chert, and spheroids no longer form discrete nodules, yet still display characteristic concentric bands of pure and impure microcrystalline quartz and chalcedony. Petrographic observations show that the purer silica bands are composed of void‐filling cement that precipitated in curved dilational fractures, and do not reflect geochemical growth‐banding in the manner of Liesegang phenomena invoked to explain concentrically banded chert nodules in limestone. Chertification of bedded siliceous sediment can occur more shallowly (< 100 m) and rapidly (< 1 Myr) than the bulk silica phase transitions forming porcelanite or siliceous shale in the Monterey Formation and other hemipelagic/pelagic siliceous deposits. Early diagenesis is indicated by physical properties, deformational style and oxygen‐isotopic composition of chert spheroids. Early‐formed cherts formed by pore‐filling impregnation of the purest primary diatomaceous beds, along permeable fractures and in calcareous–siliceous strata.
Otomycosis due to Aspergillus spp. in a dog: case report and literature review
Authors: Coyner Kimberly 
Published: May 2010

AbstractThis report describes the clinical findings, clinicopathology and treatment of otomycosis caused by Aspergillus spp. in an atopic dog affected by chronic unilateral purulent otitis externa unresponsive to topical and oral antibiotics and antifungal treatments. Cytology of otic exudate revealed neutrophils and septate fungal hyphae, and otic culture grew Aspergillus spp. and no bacteria. Treatments included allergen‐specific immunotherapy, topical and oral antifungal therapy and anti‐inflammatory steroid therapy. Final resolution occurred after treatment of the underlying hypersensitivity disorder, administration of topical ketoconazole and debridement of infectious ear exudate. Otomycosis due to filamentous fungi may, as in humans, occur in dogs with ear canals compromised by pre‐existing allergic or bacterial otitis, and possibly previous antibiotic therapy. Antifungal medications provided clinical improvement, but the key to successful treatment was the restoration of the normal physiology of the external auditory canal.