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1.
《IRBM》2007,28(1):42-48
Dental implant-associated infections as peri-implantitis represent one of the major causes of osteointegration failures of oral implants. Adhesion of Porphyromonas gingivalis, one of the bacterial strains mainly involved in such infections, is tightly dependent on the topographical and/or physico-chemical properties of the implant surfaces. As a matter of fact, we showed that the grafting of one bioactive polymer such as poly(sodium styrene sulfonate) onto titanium implant surfaces allowed a sensitive decrease of Staphylococcus aureus adhesion (> 40%). The aim of the study consists in evaluating the adhesion of P. gingivalis onto titanium surfaces grafted with poly(sodium stryrene sulfonate) in order to elaborate implants exhibiting appropriate inhibiting properties towards the adhesion of periodontal pathogens. The grafting of poly(sodium stryrene sulfonate) onto titanium surfaces is carried out in two steps: chemical oxydation of titanium to initiate radical species then grafting of poly(sodium stryrene sulfonate) by radical polymerization. Chemical characterization of the surfaces is achieved by Fourier transformed infrared spectroscopy (FTIR). Bacterial adhesion was studied on grafted and non grafted (control) titanium surfaces, preadsorbed or not by plasmatic proteins. Protein adsorption as well as bacteria adhesion is followed by fluorescence spectroscopy by using proteins or bacteria previously labelled with fluorescence probes; the quantification of adsorption and bacteria adhesion are performed by image analysis. Results showed that protein adsorption is more important (~3 times) and that P. gingivalis adhesion is strongly inhibited (~73%) onto poly(sodium styrene sulfonate) grafted surfaces when compared to titanium control. Moreover, the inhibition of bacterial adhesion on grafted surfaces preadsorbed with plasma proteins is comparable to that observed on grafted surfaces preadsorbed with fibronectin. In conclusion, the obtained results evidenced that the grafting of titanium surface by poly(sodium styrene sulfonate) led to significant inhibition of P. gingivalis adhesion and that this inhibitory activity involved adsorbed proteins. Poly(sodium styrene sulfonate) grafted titanium surfaces present a high interest for the elaboration of oral implants in various clinical dental applications. 相似文献
2.
D. P. Sleeman J. Davenport S. J. More T. A. Clegg J. M. Griffin I. O’Boyle 《European Journal of Wildlife Research》2009,55(3):267-278
This study’s objective was to estimate the permeability of barriers to badger immigration during the Irish Four Area project.
These barriers were at the boundaries of removal areas, where there was proactive culling of badgers. Data from the last 3 years
of the study were used. Each length of barrier was allocated a space within the removal area. These were further sub-divided
into spaces of 0–2, 2–5 km and sometimes of more than 5 km from the edge of the removal area. It is assumed that all, or some,
of the badgers caught within these spaces came across the barriers. The barriers were one of the following: external buffers,
sea, rivers and political boundaries. The total lengths of the barriers in all areas were: external buffer 128.5 km; sea 70.9 km;
river 78.6 km; political 32.2 km. We assume three scenarios: (1) all badgers caught in the final 3 years were immigrants,
(2) 75% were immigrants or (3) 50% were immigrants. We test these scenarios using chi-square tests, applying internal buffers
of 1 km to counter movements of badgers across zones. Using this approach and multivariate analysis, we found that the permeability
of barrier types varied, with sea and external buffers being the most effective barriers. The combined capture data are further
examined by the sex ratio in each range, and then the sex ratio in total. Equal numbers of males and females were found, but
the source populations were probably predominantly female. If badger management options are to achieve maximum benefits, then
the field effectiveness of such barriers needs to be understood. 相似文献
3.
Ivonne I. Vega‐Ruiz Jos Alfredo Castillo‐Guerrero Eduardo Palacios Guillermo Fernndez 《Journal of Field Ornithology》2019,90(4):325-334
The islands of Bahía Santa María‐La Reforma, Sinaloa, Mexico, host the largest breeding population of the western race of American Oystercatchers (Haematopus palliatus frazari). This resident shorebird has a small breeding range restricted to northwestern Mexico and, although listed as endangered, little is known about their breeding biology. We estimated the number of pairs on the El Rancho and Melendres islands, the detection rate of pairs in different habitats, and the relationship between habitat length and number of pairs during three breeding seasons (2016–2018). In 2016 and 2017, the number of pairs peaked in mid‐April (97 and 95 pairs, respectively) at El Rancho, and in early May and early April (50 and 42 pairs, respectively) at Melendres. In 2018, both islands had the maximum number of pairs during mid‐May, with 109 pairs at El Rancho and 42 at Melendres. Detectability of breeding pairs in plots with sandy beach and dune habitats was higher (86–100%) than in those with mangrove habitat (22%). Detectability was associated with habitat type and should be considered in estimating the population size of this subspecies. We estimated that ~ 11% of the total frazari American Oystercatcher population breeds on these two small islands. The density of breeding pairs varied between habitats (range = 0–13 pairs/km). We also found a positive relationship between the number of pairs and plot length, suggesting that habitat availability might be a limiting factor for populations of American Oystercatchers in Mexico. 相似文献
4.
Lee Turin Dickman Nate G. McDowell Charlotte Grossiord Adam D. Collins Brett T. Wolfe Matteo Detto S. Joseph Wright Jos A. Medina‐Vega Devin Goodsman Alistair Rogers Shawn P. Serbin Jin Wu Kim S. Ely Sean T. Michaletz Chonggang Xu Lara Kueppers Jeffrey Q. Chambers 《Plant, cell & environment》2019,42(5):1705-1714
Nonstructural carbohydrates (NSCs) are essential for maintenance of plant metabolism and may be sensitive to short‐ and long‐term climatic variation. NSC variation in moist tropical forests has rarely been studied, so regulation of NSCs in these systems is poorly understood. We measured foliar and branch NSC content in 23 tree species at three sites located across a large precipitation gradient in Panama during the 2015–2016 El Niño to examine how short‐ and long‐term climatic variation impact carbohydrate dynamics. There was no significant difference in total NSCs as the drought progressed (leaf P = 0.32, branch P = 0.30) nor across the rainfall gradient (leaf P = 0.91, branch P = 0.96). Foliar soluble sugars decreased while starch increased over the duration of the dry period, suggesting greater partitioning of NSCs to storage than metabolism or transport as drought progressed. There was a large variation across species at all sites, but total foliar NSCs were positively correlated with leaf mass per area, whereas branch sugars were positively related to leaf temperature and negatively correlated with daily photosynthesis and wood density. The NSC homoeostasis across a wide range of conditions suggests that NSCs are an allocation priority in moist tropical forests. 相似文献
5.
《Acta Oecologica》2006,29(1):104-113
Mediterranean forests in northern Morocco have been studied. Tree species composition and abundance were investigated in 84 forest sites, distributed throughout the sandstone formation of the Tangier region. The relative abundance of 15 tree and arborescent shrub species was related, by ordination analysis, to altitude, disturbance by fire, and soil fertility. High-elevation forests were dominated by Cedrus atlantica, Quercus pyrenaica and Pinus pinaster. Sacred forests (protected as holy burial places) had a distinct stand structure, and were considered as refuges, for maintaining biodiversity at landscape scale. The evergreen oak Quercus suber and the semideciduous Quercus canariensis co-dominated the lowland forests. The mean basal area of the studied forests was 34 m2 ha–1. The mean trunk size (dbh) for Q. suber was 24 cm and for Q. canariensis 36.5 cm; in both cases there were indications of declining regeneration at population level. A comparative biogeographical analysis with the equivalent region in southern Spain (separated by the Strait of Gibraltar; 14 km wide), indicated a possible biodiversity loss in the Moroccan forests. 相似文献
6.
A combined morphometric analysis of foot form and its association with sex,stature, and body mass
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Jacqueline Domjanic Horst Seidler Philipp Mitteroecker 《American journal of physical anthropology》2015,157(4):582-591
Objectives: Morphometric analysis of footprints is a classic means for orthopedic diagnosis. In forensics and physical anthropology, it is commonly used for the estimation of stature and body mass. We studied individual variation and sexual dimorphism of foot dimensions and footprint shape by a combination of classic foot measurements and geometric morphometric methods. Methods: Left and right feet of 134 healthy adult males and females were scanned twice with a 3D optical laser scanner, and stature as well as body mass were recorded. Foot length and width were measured on the 3D scans. The 2D footprints were extracted as the plantar‐most 2 mm of the 3D scans and measured with 85 landmarks and semilandmarks. Results: Both foot size and footprint shape are sexually dimorphic and relate to stature and body mass. While dimorphism in foot length largely results from dimorphism in stature, dimorphism in footprint shape partly owes to the dimorphism in BMI. Stature could be estimated well based on foot length (R2 = 0.76), whereas body mass was more closely related to foot width (R2 = 0.62). Sex could be estimated correctly for 95% of the individuals based on a combination of foot width and length. Discussion: Geometric morphometrics proved to be an effective tool for the detailed analysis of footprint shape. However, for the estimation of stature, body mass, and sex, shape variables did not considerably improve estimates based on foot length and width. Am J Phys Anthropol 157:582–591, 2015. © 2015 Wiley Periodicals, Inc. 相似文献
7.
Henk‐Jan T. Hoving William F. Gilly Unai Markaida Kelly J. Benoit‐Bird Zachary W. ‐Brown Patrick Daniel John C. Field Liz Parassenti Bilin Liu Bernardita Campos 《Global Change Biology》2013,19(7):2089-2103
Dosidicus gigas (jumbo or Humboldt squid) is a semelparous, major predator of the eastern Pacific that is ecologically and commercially important. In the Gulf of California, these animals mature at large size (>55 cm mantle length) in 1–1.5 years and have supported a major commercial fishery in the Guaymas Basin during the last 20 years. An El Niño event in 2009–2010, was accompanied by a collapse of this fishery, and squid in the region showed major changes in the distribution and life‐history strategy. Large squid abandoned seasonal coastal‐shelf habitats in 2010 and instead were found in the Salsipuedes Basin to the north, an area buffered from the effects of El Niño by tidal upwelling and a well‐mixed water column. The commercial fishery also relocated to this region. Although large squid were not found in the Guaymas Basin from 2010 to 2012, small squid were abundant and matured at an unusually small mantle‐length (<30 cm) and young age (approximately 6 months). Juvenile squid thus appeared to respond to El Niño with an alternative life‐history trajectory in which gigantism and high fecundity in normally productive coastal‐shelf habitats were traded for accelerated reproduction at small size in an offshore environment. Both small and large mature squid, were present in the Salsipuedes Basin during 2011, indicating that both life‐ history strategies can coexist. Hydro‐acoustic data, reveal that squid biomass in this study area nearly doubled between 2010 and 2011, primarily due to a large increase in small squid that were not susceptible to the fishery. Such a climate‐driven switch in size‐at‐maturity may allow D. gigas to rapidly adapt to and cope with El Niño. This ability is likely to be an important factor in conjunction with longerterm climate‐change and the potential ecological impacts of this invasive predator on marine ecosystems. 相似文献
8.
Habitat predictors of genetic diversity for two sympatric wetland‐breeding amphibian species
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Anna M. McKee John C. Maerz Lora L. Smith Travis C. Glenn 《Ecology and evolution》2017,7(16):6271-6283
Population genetic diversity is widely accepted as important to the conservation and management of wildlife. However, habitat features may differentially affect evolutionary processes that facilitate population genetic diversity among sympatric species. We measured genetic diversity for two pond‐breeding amphibian species (Dwarf salamanders, Eurycea quadridigitata; and Southern Leopard frogs, Lithobates sphenocephalus) to understand how habitat characteristics and spatial scale affect genetic diversity across a landscape. Samples were collected from wetlands on a longleaf pine reserve in Georgia. We genotyped microsatellite loci for both species to assess population structures and determine which habitat features were most closely associated with observed heterozygosity and rarefied allelic richness. Both species exhibited significant population genetic structure; however, structure in Southern Leopard frogs was driven primarily by one outlier site. Dwarf salamander allelic richness was greater at sites with less surrounding road area within 0.5 km and more wetland area within 1.0 and 2.5 km, and heterozygosity was greater at sites with more wetland area within 0.5 km. In contrast, neither measure of Southern Leopard frog genetic diversity was associated with any habitat features at any scale we evaluated. Genetic diversity in the Dwarf salamander was strongly associated with land cover variables up to 2.5 km away from breeding wetlands, and/or results suggest that minimizing roads in wetland buffers may be beneficial to the maintenance of population genetic diversity. This study suggests that patterns of genetic differentiation and genetic diversity have associations with different habitat features across different spatial scales for two syntopic pond‐breeding amphibian species. 相似文献
9.
Siegfried L. Krauss Elizabeth A. Sinclair John D. Bussell Richard J. Hobbs 《Ecology and evolution》2013,3(7):2138-2149
An increasingly important practical application of the analysis of spatial genetic structure within plant species is to help define the extent of local provenance seed collection zones that minimize negative impacts in ecological restoration programs. Here, we derive seed sourcing guidelines from a novel range‐wide assessment of spatial genetic structure of 24 populations of Banksia menziesii (Proteaceae), a widely distributed Western Australian tree of significance in local ecological restoration programs. An analysis of molecular variance (AMOVA) of 100 amplified fragment length polymorphism (AFLP) markers revealed significant genetic differentiation among populations (ΦPT = 0.18). Pairwise population genetic dissimilarity was correlated with geographic distance, but not environmental distance derived from 15 climate variables, suggesting overall neutrality of these markers with regard to these climate variables. Nevertheless, Bayesian outlier analysis identified four markers potentially under selection, although these were not correlated with the climate variables. We calculated a global R‐statistic using analysis of similarities (ANOSIM) to test the statistical significance of population differentiation and to infer a threshold seed collection zone distance of ~60 km (all markers) and 100 km (outlier markers) when genetic distance was regressed against geographic distance. Population pairs separated by >60 km were, on average, twice as likely to be significantly genetically differentiated than population pairs separated by <60 km, suggesting that habitat‐matched sites within a 30‐km radius around a restoration site genetically defines a local provenance seed collection zone for B. menziesii. Our approach is a novel probability‐based practical solution for the delineation of a local seed collection zone to minimize negative genetic impacts in ecological restoration. 相似文献
10.
Local adaptations in bryophytes revisited: the genetic structure of the calcium‐tolerant peatmoss Sphagnum warnstorfii along geographic and pH gradients
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Eva Mikulášková Michal Hájek Adam Veleba Matthew G. Johnson Tomáš Hájek Jonathan A. Shaw 《Ecology and evolution》2015,5(1):229-242
Bryophytes dominate some ecosystems despite their extraordinary sensitivity to habitat quality. Nevertheless, some species behave differently across various regions. The existence of local adaptations is questioned by a high dispersal ability, which is thought to redistribute genetic variability among populations. Although Sphagnum warnstorfii is an important ecosystem engineer in fen peatlands, the causes of its rather wide niche along the pH/calcium gradient are poorly understood. Here, we studied the genetic variability of its global populations, with a detailed focus on the wide pH/calcium gradient in Central Europe. Principal coordinates analysis of 12 polymorphic microsatellite loci revealed a significant gradient coinciding with water pH, but independent of geography; even samples from the same fens were clearly separated along this gradient. However, most of the genetic variations remained unexplained, possibly because of the introgression from phylogenetically allied species. This explanation is supported by the small heterogeneous cluster of samples that appeared when populations morphologically transitional to S. subnites, S. rubellum, or S. russowii were included into the analysis. Alternatively, this unexplained variation might be attributed to a legacy of glacial refugia with recently dissolved ecological and biogeographic consequences. Isolation by distance appeared at the smallest scale only (up to 43 km). Negative spatial correlations occurred more frequently, mainly at long distances (up to 950 km), implying a genetic similarity among samples which are very distant geographically. Our results confirm the high dispersal ability of peatmosses, but simultaneously suggested that their ability to cope with a high pH/calcium level is at least partially determined genetically, perhaps via specific physiological mechanisms or a hummock‐forming ability. 相似文献
11.
N. Franch M. Clavero M. Garrido N. Gaya V. López Q. Pou-Rovira J. M. Queral 《Biological invasions》2008,10(8):1327-1331
Oriental weatherfish has become an invasive fish species in many temperate areas. In this work we report the presence of an
established weatherfish population in northeastern Iberian Peninsula and describe, for the first time in Europe, a clear range
expansion. The species was first located in the Ebro River Delta in 2001 and has since been detected in 31 UTM 1 × 1 km quadrates.
The capture of over 1,000 weatherfish shows that its population is composed by both juvenile and adult individuals. Weatherfish
occupies mostly the web of irrigation channels associated with rice culture, although it has also been detected in rice fields
and in the Ebro River. The expansion of the species in the area seems to be limited by water conductivity. An additional location
for the species in the Ter basin (some 300 km to the north) suggests that inter-basin expansion could be occurring. This new
fish invasion reinforces the need to implement strict controls to the trade and culture of ornamental fish. 相似文献
12.
Human footprint fossils have provided essential evidence about the evolution of human bipedalism as well as the social dynamics of the footprint makers, including estimates of speed, sex and group composition. Generally such estimates are made by comparing footprint evidence with modern controls; however, previous studies have not accounted for the variation in footprint dimensions coming from load bearing activities. It is likely that a portion of the hominins who created these fossil footprints were carrying a significant load, such as offspring or foraging loads, which caused variation in the footprint which could extend to variation in any estimations concerning the footprint’s maker. To identify significant variation in footprints due to load-bearing tasks, we had participants (N = 30, 15 males and 15 females) walk at a series of speeds carrying a 20kg pack on their back, side and front. Paint was applied to the bare feet of each participant to create footprints that were compared in terms of foot length, foot width and foot area. Female foot length and width increased during multiple loaded conditions. An appreciation of footprint variability associated with carrying loads adds an additional layer to our understanding of the behavior and morphology of extinct hominin populations. 相似文献
13.
In the W-Aures (Algeria), the El Kantara pass displays about 50 m of Red Marls overlying the Maastrichtian limestones with Laffitteina. The Red Marls are, in their turn, overlain by the Thanetian marly limestones of the river El Haï. The micropaleontological inventory of these Red Marls establishes the co-occurrence of subaerian (Microcodium = Paronipora), fresh-water (Charophyta) and marine microfossils (Foraminifers). The stratigraphical significance of these microfossils is discussed. The upper part of the Red Marls, yielding abundant Valvulina and scarce Glomalveolina, is of Thanetian age. The age of the lower part is less established, but the occurrence of Microcodium suggests a Thanetian age too. Located at the margin of the northern opening of the trans-Saharan epeiric sea, the El Kantara section establishes a Thanetian age for the beginning of the Paleocene transgression. Danian deposits are missing, in spite of the absence of an obvious hiatus on the field. After general emersion during the early Paleocene, the Thanetian transgression starts with the set up of lakes at the depositional area of the Red Marls. Marine influences, limited at first, become gradually prevailing, and end with the deposition of neritic marly limestones of river El Haï. 相似文献
14.
Les pistes dinosauroïdes du Trias moyen français : interprétation et réévaluation de la nomenclature
Numerous dinosauroid footprints which showing sometimes manus imprint mark were gathered, since 1960, from the lower sandstones Triassic formations of the eastern border of the Massif Central (France). Tracks bearing levels are dated from palynological, micropalaeontological and palichnological data. They belong to the period upper Anisian-lower Ladinian. The paleontological results show bipedal digitigrade reptiles with erected, long hind limbs, having also pentadactyl mani and (II-IV) tridactyl feet. The osteological feet inferred structure is like that of Ceratosauria of Late Triassic age. The skeletons of first Dinosauria, diversified already well, are known in summit Ladinian and lower Carnien and those of their ancestors, Dinosauriformes, in Ladinian. And, for this reason, the aniso-ladinian dinosauroid footprints are ascribed to these last animals which thus appeared earlier, to Anisan even to late Olenekian. The chirotheroid hands show a “pseudosuchian” origin which possibly took place during the late Olenekian; feet modifications of these Crurotarsi being characterized by I and V digits reduction and a meso-tarsal joint. The Anisian-Ladinian dinosauroid footprints are ascribed to the ichnospecies Coelurosaurichnus perriauxi and Anchisauripus bibractensis. The discriminant analysis computed from these latter ichnospecies, and others from the German Triassic, French and USA Hettangian indicate that C. perriauxi and A. bibractensis can not be included into Grallator sensu Lull, 1953 or Coelurosaurichnus of Franconie. By this way, these taxa are well original and till now, there was no reason to change their nomenclature. Nevertheless because the numerous changes of Grallator which gathers now, most of dinosauroid footprints, it could be possible to include them into Grallator for the feet and into Atreipus when the manus trace is connected with the foot. 相似文献
15.
In sea stars, adhesion takes place at the level of a multitude of small appendages, the tube feet. It involves the secretion
of an adhesive material which, after tube foot detachment, remains on the substratum as a footprint. It was previously reported
that the two main organic components of this material are proteins and carbohydrates. The carbohydrate moiety of the adhesive
secretion of Asterias rubens was investigated using a set of 16 lectins which were used on sections through tube feet, on footprints, and on the proteins
extracted from these footprints. After gel electrophoresis, these proteins separate into eight protein bands which were named
sea star footprint proteins (Sfps). Eleven lectins label the tube foot epidermis at the level of the adhesive cells, four
react with footprints, and eight with two of the extracted footprint proteins, which are therefore classified as glycoproteins.
Sfp-290 appears to bear mostly N-linked oligosaccharides and Sfp-210 principally O-linked oligosaccharides. The outer chains
of both glycoproteins enclose galactose, N-acetylgalactosamine, fucose, and sialic acid residues. Another part of the carbohydrate fraction of the footprints would be
in the form of larger molecules, such as sialylated proteoglycans. These two types of glycoconjugates are presumably key components
of the sea star temporary adhesive providing both cohesive and adhesive contributions through electrostatic interactions by
the polar and hydrogen-bonding functional groups of their glycan chains. 相似文献
16.
《L'Anthropologie》2022,126(4):103067
Hominin footprints are a particular remain in paleoanthropology representing brief moments of life of extinct individuals. Footprints not only provide information on the locomotor behavior of fossil taxa but also on their body characteristics such as their stature. This stature is usually estimated from the length of the footprints based on the well-known foot length to stature ratio. However, footprint length does not result only from the foot length but of a combination of factors. Therefore, it is necessary to investigate the relationships between footprint length and stature of individuals using experimental approaches. Secondly, recent discoveries of fossil footprints have led to the estimation of statures from isolated footprints. However, such estimates may be biased because of the intraindividual morphometric variation of the footprints. Moreover, footprints may also be incomplete making it impossible to measure the length and therefore the estimation of a stature. The search for relationships between stature and other morphometric variables is therefore necessary to have the most accurate picture possible of the individuals who left these tracks. In this context, this article reports the results of an experimental study that aims to determine the relationships between the stature of individuals and different morphometric variables and to quantify the intraindividual variation of each variable. Thus, 21 morphometric variables were measured on a total of 175 experimental footprints left by 20 individuals in an experimental area composed of loose sand. Statistical analyses show that footprint lengths are not only the variables most correlated with stature but also those with the least intraindividual variation. However, estimation of stature from footprints left by fossil hominins is subject to three types of uncertainties: residuals from linear regression, intraindividual variation that can be particularly large in soft substrates, and the application of relationships defined on modern populations to fossil taxa. 相似文献
17.
Year‐round movements of sympatric Fork‐tailed (Oceanodroma furcata) and Leach's (O. leucorhoa) storm‐petrels
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Luke R. Halpin Ingrid L. Pollet Christopher Lee Ken H. Morgan Harry R. Carter 《Journal of Field Ornithology》2018,89(3):207-220
Long‐distance movements are characteristic of most seabirds in the order Procellariiformes. However, little is known about the migration and foraging ranges of many of the smaller species in this order, especially storm‐petrels (Hydrobatidae). We used Global Location Sensors to document the year‐round movements of sympatrically breeding Fork‐tailed Storm‐Petrels (Oceanodroma furcata) and Leach's Storm‐Petrels (O. leucorhoa) from the Gillam Islands located northwest of Vancouver Island, British Columbia, Canada. In 2016, breeding Fork‐tailed (N = 5) and Leach's (N = 2) storm‐petrels traveled maximum distances of ~1550–1600 km from their colony to a region that has a wide shelf with major canyons creating a highly productive foraging area. After the breeding season, Fork‐tailed Storm‐Petrels (N = 2) traveled to similar areas west of the Gillam Islands, a maximum distance of ~3600 km from the breeding colony, and remained in the North Pacific Ocean and north of the Subarctic Boundary for an average of 5.4 mo. Post‐breeding Leach's Storm‐Petrels (N = 2) moved south to the Eastern Tropical Pacific, west of central Mexico, Ecuador, and northern Peru, an estimated maximum distance of ~6700 km from their breeding colony, and remained there for an average of 7.2 mo. Carbon (δ13C) and nitrogen (δ15N) stable isotope analyses of feathers revealed niche separation between Fork‐tailed (N = 21) and Leach's (N = 53) storm‐petrels. The wide range of δ15N values in the feathers of Leach's Storm‐Petrels (N = 53) suggests that they foraged at a variety of trophic levels during the non‐breeding season. Our results demonstrate that storm‐petrels have large core foraging areas and occupy vast oceanic areas in the Pacific during their annual cycle. However, given the coarse precision of Global Location Sensors, additional study is needed to identify the specific areas used by each species during both breeding and non‐breeding periods. 相似文献
18.
The world's agricultural system has come under increasing scrutiny recently as an important driver of global climate change, creating a demand for indicators that estimate the climatic impacts of agricultural commodities. Such carbon footprints, however, have in most cases excluded emissions from land‐use change and the proposed methodologies for including this significant emissions source suffer from different shortcomings. Here, we propose a new methodology for calculating land‐use change carbon footprints for agricultural commodities and illustrate this methodology by applying it to three of the most prominent agricultural commodities driving tropical deforestation: Brazilian beef and soybeans, and Indonesian palm oil. We estimate land‐use change carbon footprints in 2010 to be 66 tCO2/t meat (carcass weight) for Brazilian beef, 0.89 tCO2/t for Brazilian soybeans, and 7.5 tCO2/t for Indonesian palm oil, using a 10 year amortization period. The main advantage of the proposed methodology is its flexibility: it can be applied in a tiered approach, using detailed data where it is available while still allowing for estimation of footprints for a broad set of countries and agricultural commodities; it can be applied at different scales, estimating both national and subnational footprints; it can be adopted to account both for direct (proximate) and indirect drivers of land‐use change. It is argued that with an increasing commercialization and globalization of the drivers of land‐use change, the proposed carbon footprint methodology could help leverage the power needed to alter environmentally destructive land‐use practices within the global agricultural system by providing a tool for assessing the environmental impacts of production, thereby informing consumers about the impacts of consumption and incentivizing producers to become more environmentally responsible. 相似文献
19.
The functional anatomy of the hindlimb of bipedal dinosaurs has been intensively studied. Yet, surprisingly little work has been done concerning functional adaptation of digits for terrestrial locomotion. While complete and articulated pes skeletons are scarce, pes shape is abundantly recorded by fossil footprints. We elucidate the significance of footprint shape and size for locomotion using a large sample (n = 303) of tridactyl dinosaur footprints from a broad range of geographical localities and time slots. Size and shape variation are characterized separately for theropods and ornithischians, the two principal trackmaker taxa. At smaller sizes, theropod footprints are best discriminated from ornithischian footprints by their smaller interdigital angle and larger projection of digit III; at larger sizes digital widths are effective discriminants. Ornithischian footprints increase in size from the Early Jurassic to the Late Cretaceous, a trend not observed in theropod footprints. Size and function are argued to be important determinants of footprint shape, and an attempt made to infer function from shape. Digit III projection and length-to-width ratio of the footprints are negatively correlated with size in both groups; digit impression width is positively correlated with size only in ornithischians. Digit III projection appears to be positively correlated with cursorial ability. Increased interdigital angles are associated with a decrease in digital width, possibly an adaptation for stability. Weak digit III projection and increased digital width are interpreted as adaptations for graviportality. Footprints yield great potential for the understanding of the functional morphology of dinosaur feet. 相似文献
20.
Rhodora V. Azanza Laura T. David Roselle T. Borja Iris U. Baula Yasuwo Fukuyo 《Harmful algae》2008,7(3):324
A massive fish kill and water discoloration were reported off the western coast of Puerto Princesa, Palawan, Philippines in March 2005. Phytoplankton analysis revealed a near monospecific bloom of the dinoflagellate, Cochlodinium polykrikoides, with cell concentrations ranging from 2.5 × 105 to 3.2 × 106 cells per liter. Ground truth data were supplemented by processed satellite images from MODIS Aqua Level 2 data (1 km resolution) from January to April 2005, which revealed high surface chlorophyll-a levels (up to 50 mg/m3) offshore of west and southwest Palawan as early as February 2005. The bloom extended 310 km in length and 80 km in width at its peak in March off the central coast (Puerto Princesa). By April, the bloom declined in intensity, but was still apparent along the northern coast (El Nido). Fluctuations in chlorophyll levels off the western coast of Sabah, Malaysia and Brunei during this time period suggested that the bloom was not limited to the coast of Palawan. Satellite imagery from Sabah in late January revealed a plume of chl-a that is believed to be the source of the C. polykrikoides bloom in Palawan. This plume drifted offshore, advected northward via the basin-wide counterclockwise gyre, and reached nutrient-rich, upwelled waters near Palawan (due to a positive wind stress curl) where the dinoflagellate bloomed and persisted for 2 months from March to April 2005. 相似文献