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Sample records for invasive mutualists erode

  1. Invasive plant erodes local song diversity in a migratory passerine

    Science.gov (United States)

    Yvette K. Ortega; Aubree Benson; Erick Greene

    2014-01-01

    Exotic plant invasions threaten ecosystems globally, but we still know little about the specific consequences for animals. Invasive plants can alter the quality of breeding habitat for songbirds, thereby impacting important demographic traits such as dispersal, philopatry, and age structure. These demographic effects may in turn alter song-learning conditions to affect...

  2. Invasive Asian Fusarium – Euwallacea ambrosia beetle mutualists pose a serious threat to forests, urban landscapes and the avocado industry

    Science.gov (United States)

    Several species of the ambrosia beetle Euwallacea (Coleoptera: Curculionidae: Scolytinae) cultivate Ambrosia Fusarium Clade (AFC) species in their galleries as a source of food. Like all other scolytine beetles in the tribe Xyleborini, Euwallacea are thought to be obligate mutualists with their fung...

  3. Habitat destruction in mutualistic metacommunities

    NARCIS (Netherlands)

    Prakash, S.; de Roos, A.M.

    2004-01-01

    We investigate a mutualistic metacommunity where the strength of the mutualistic interaction between species is measured by theextent to which the presence of one species on a patch either reduces the extinction rate of the others present on the same patch orincreases their ability to colonize other

  4. Ranking species in mutualistic networks

    Science.gov (United States)

    Domínguez-García, Virginia; Muñoz, Miguel A.

    2015-02-01

    Understanding the architectural subtleties of ecological networks, believed to confer them enhanced stability and robustness, is a subject of outmost relevance. Mutualistic interactions have been profusely studied and their corresponding bipartite networks, such as plant-pollinator networks, have been reported to exhibit a characteristic ``nested'' structure. Assessing the importance of any given species in mutualistic networks is a key task when evaluating extinction risks and possible cascade effects. Inspired in a recently introduced algorithm -similar in spirit to Google's PageRank but with a built-in non-linearity- here we propose a method which -by exploiting their nested architecture- allows us to derive a sound ranking of species importance in mutualistic networks. This method clearly outperforms other existing ranking schemes and can become very useful for ecosystem management and biodiversity preservation, where decisions on what aspects of ecosystems to explicitly protect need to be made.

  5. Evolutionary origins and diversification of proteobacterial mutualists.

    Science.gov (United States)

    Sachs, Joel L; Skophammer, Ryan G; Bansal, Nidhanjali; Stajich, Jason E

    2014-01-22

    Mutualistic bacteria infect most eukaryotic species in nearly every biome. Nonetheless, two dilemmas remain unresolved about bacterial-eukaryote mutualisms: how do mutualist phenotypes originate in bacterial lineages and to what degree do mutualists traits drive or hinder bacterial diversification? Here, we reconstructed the phylogeny of the hyperdiverse phylum Proteobacteria to investigate the origins and evolutionary diversification of mutualistic bacterial phenotypes. Our ancestral state reconstructions (ASRs) inferred a range of 34-39 independent origins of mutualist phenotypes in Proteobacteria, revealing the surprising frequency with which host-beneficial traits have evolved in this phylum. We found proteobacterial mutualists to be more often derived from parasitic than from free-living ancestors, consistent with the untested paradigm that bacterial mutualists most often evolve from pathogens. Strikingly, we inferred that mutualists exhibit a negative net diversification rate (speciation minus extinction), which suggests that mutualism evolves primarily via transitions from other states rather than diversification within mutualist taxa. Moreover, our ASRs infer that proteobacterial mutualist lineages exhibit a paucity of reversals to parasitism or to free-living status. This evolutionary conservatism of mutualism is contrary to long-standing theory, which predicts that selection should often favour mutants in microbial mutualist populations that exploit or abandon more slowly evolving eukaryotic hosts.

  6. Interspecific Competition Underlying Mutualistic Networks

    Science.gov (United States)

    Maeng, Seong Eun; Lee, Jae Woo; Lee, Deok-Sun

    2012-03-01

    Multiple classes of interactions may exist affecting one another in a given system. For the mutualistic networks of plants and pollinating animals, it has been known that the degree distribution is broad but often deviates from power-law form more significantly for plants than animals. To illuminate the origin of such asymmetry, we study a model network in which links are assigned under generalized preferential-selection rules between two groups of nodes and find the sensitive dependence of the resulting connectivity pattern on the model parameters. The nonlinearity of preferential selection can come from interspecific interactions among animals and among plants. The model-based analysis of real-world mutualistic networks suggests that a new animal determines its partners not only by their abundance but also under the competition with existing animal species, which leads to the stretched-exponential degree distributions of plants.

  7. Fungal Adaptations to Mutualistic Life with Ants

    DEFF Research Database (Denmark)

    Kooij, Pepijn Wilhelmus

    Fungus-growing ants (Attini) feed off a fungus they cultivate in a mutualistic symbiosis in underground chambers by providing it substrate they collect outside the colony. The tribe of Attine ants ranges from small colonies of the paleo- and basal Attine species with a few hundred workers that fo...... that the fungus evolved some incredible adaptations to a mutualistic life with the ants....

  8. Erodibility of cemented materials

    CSIR Research Space (South Africa)

    Gass, BG

    1993-03-01

    Full Text Available The use of stabilised layers is cost effective in road construction in South Africa. Some stabilised materials have however been found to be susceptible to erosion. To identify erodible materials the Erosion Test was developed in 1989...

  9. Puerto Rico Soil Erodibility (Kffact)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Puerto Rico soil erodibility (Kffactor) - low values indicate low vulnerability to erosion, higher values mean higher susceptibility to runoff.

  10. Societal Forces That ERODE Creativity

    Science.gov (United States)

    Sternberg, Robert; Kaufman, James C.

    2018-01-01

    Background/Context: Creativity is an indispensable force in intellectual, social, cultural, and economic development. Yet societal forces conspire to erode it. Educators have despaired for many years over how schools often fail to encourage creativity, but society as a whole is just as guilty. But how do schools and society fail to encourage, or…

  11. Metabolic Environments and Genomic Features Associated with Pathogenic and Mutualistic Interactions between Bacteria and Plants is accepted for publication in MPMI

    Energy Technology Data Exchange (ETDEWEB)

    Karpinets, Tatiana V [ORNL; Park, Byung H [ORNL; Syed, Mustafa H [ORNL; Klotz, Martin G [University of North Carolina, Charlotte; Uberbacher, Edward C [ORNL

    2014-01-01

    Most bacterial symbionts of plants are phenotypically characterized by their parasitic or matualistic relationship with the host; however, the genomic characteristics that likely discriminate mutualistic symbionts from pathogens of plants are poorly understood. This study comparatively analyzed the genomes of 54 plant-symbiontic bacteria, 27 mutualists and 27 pathogens, to discover genomic determinants of their parasitic and mutualistic nature in terms of protein family domains, KEGG orthologous groups, metabolic pathways and families of carbohydrate-active enzymes (CAZymes). We further used all bacteria with sequenced genomesl, published microarrays and transcriptomics experimental datasets, and literature to validate and to explore results of the comparison. The analysis revealed that genomes of mutualists are larger in size and higher in GC content and encode greater molecular, functional and metabolic diversity than the investigated genomes of pathogens. This enriched molecular and functional enzyme diversity included constructive biosynthetic signatures of CAZymes and metabolic pathways in genomes of mutualists compared with catabolic signatures dominant in the genomes of pathogens. Another discriminative characteristic of mutualists is the co-occurence of gene clusters required for the expression and function of nitrogenase and RuBisCO. Analysis of previously published experimental data indicate that nitrogen-fixing mutualists may employ Rubisco to fix CO2 not in the canonical Calvin-Benson-Basham cycle but in a novel metabolic pathway, here called Rubisco-based glycolysis , to increase efficiency of sugar utilization during the symbiosis with plants. An important discriminative characteristic of plant pathogenic bacteria is two groups of genes likely encoding effector proteins involved in host invasion and a genomic locus encoding a putative secretion system that includes a DUF1525 domain protein conserved in pathogens of plants and of other organisms. The

  12. The functional consequences of mutualistic network architecture.

    Directory of Open Access Journals (Sweden)

    José M Gómez

    Full Text Available The architecture and properties of many complex networks play a significant role in the functioning of the systems they describe. Recently, complex network theory has been applied to ecological entities, like food webs or mutualistic plant-animal interactions. Unfortunately, we still lack an accurate view of the relationship between the architecture and functioning of ecological networks. In this study we explore this link by building individual-based pollination networks from eight Erysimum mediohispanicum (Brassicaceae populations. In these individual-based networks, each individual plant in a population was considered a node, and was connected by means of undirected links to conspecifics sharing pollinators. The architecture of these unipartite networks was described by means of nestedness, connectivity and transitivity. Network functioning was estimated by quantifying the performance of the population described by each network as the number of per-capita juvenile plants produced per population. We found a consistent relationship between the topology of the networks and their functioning, since variation across populations in the average per-capita production of juvenile plants was positively and significantly related with network nestedness, connectivity and clustering. Subtle changes in the composition of diverse pollinator assemblages can drive major consequences for plant population performance and local persistence through modifications in the structure of the inter-plant pollination networks.

  13. Unprecedented loss of ammonia assimilation capability in a urease-encoding bacterial mutualist

    Directory of Open Access Journals (Sweden)

    Wernegreen Jennifer J

    2010-12-01

    Full Text Available Abstract Background Blochmannia are obligately intracellular bacterial mutualists of ants of the tribe Camponotini. Blochmannia perform key nutritional functions for the host, including synthesis of several essential amino acids. We used Illumina technology to sequence the genome of Blochmannia associated with Camponotus vafer. Results Although Blochmannia vafer retains many nutritional functions, it is missing glutamine synthetase (glnA, a component of the nitrogen recycling pathway encoded by the previously sequenced B. floridanus and B. pennsylvanicus. With the exception of Ureaplasma, B. vafer is the only sequenced bacterium to date that encodes urease but lacks the ability to assimilate ammonia into glutamine or glutamate. Loss of glnA occurred in a deletion hotspot near the putative replication origin. Overall, compared to the likely gene set of their common ancestor, 31 genes are missing or eroded in B. vafer, compared to 28 in B. floridanus and four in B. pennsylvanicus. Three genes (queA, visC and yggS show convergent loss or erosion, suggesting relaxed selection for their functions. Eight B. vafer genes contain frameshifts in homopolymeric tracts that may be corrected by transcriptional slippage. Two of these encode DNA replication proteins: dnaX, which we infer is also frameshifted in B. floridanus, and dnaG. Conclusions Comparing the B. vafer genome with B. pennsylvanicus and B. floridanus refines the core genes shared within the mutualist group, thereby clarifying functions required across ant host species. This third genome also allows us to track gene loss and erosion in a phylogenetic context to more fully understand processes of genome reduction.

  14. Changes in Population Dynamics in Mutualistic versus Pathogenic Viruses

    Directory of Open Access Journals (Sweden)

    Marilyn J. Roossinck

    2011-01-01

    Full Text Available Although generally regarded as pathogens, viruses can also be mutualists. A number of examples of extreme mutualism (i.e., symbiogenesis have been well studied. Other examples of mutualism are less common, but this is likely because viruses have rarely been thought of as having any beneficial effects on their hosts. The effect of mutualism on the population dynamics of viruses is a topic that has not been addressed experimentally. However, the potential for understanding mutualism and how a virus might become a mutualist may be elucidated by understanding these dynamics.

  15. Mutualistic interaction between Salmonella enterica and Aspergillus niger and its effects on Zea mays colonization.

    Science.gov (United States)

    Balbontín, Roberto; Vlamakis, Hera; Kolter, Roberto

    2014-11-01

    Salmonella Typhimurium inhabits a variety of environments and is able to infect a broad range of hosts. Throughout its life cycle, some hosts can act as intermediates in the path to the infection of others. Aspergillus niger is a ubiquitous fungus that can often be found in soil or associated to plants and microbial consortia. Recently, S. Typhimurium was shown to establish biofilms on the hyphae of A. niger. In this work, we have found that this interaction is stable for weeks without a noticeable negative effect on either organism. Indeed, bacterial growth is promoted upon the establishment of the interaction. Moreover, bacterial biofilms protect the fungus from external insults such as the effects of the anti-fungal agent cycloheximide. Thus, the Salmonella-Aspergillus interaction can be defined as mutualistic. A tripartite gnotobiotic system involving the bacterium, the fungus and a plant revealed that co-colonization has a greater negative effect on plant growth than colonization by either organism in dividually. Strikingly, co-colonization also causes a reduction in plant invasion by S. Typhimurium. This work demonstrates that S. Typhimurium and A. niger establish a mutualistic interaction that alters bacterial colonization of plants and affects plant physiology. © 2014 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  16. Adaptation of flower and fruit colours to multiple, distinct mutualists.

    Science.gov (United States)

    Renoult, Julien P; Valido, Alfredo; Jordano, Pedro; Schaefer, H Martin

    2014-01-01

    Communication in plant-animal mutualisms frequently involves multiple perceivers. A fundamental uncertainty is whether and how species adapt to communicate with groups of mutualists having distinct sensory abilities. We quantified the colour conspicuousness of flowers and fruits originating from one European and two South American plant communities, using visual models of pollinators (bee and fly) and seed dispersers (bird, primate and marten). We show that flowers are more conspicuous than fruits to pollinators, and the reverse to seed dispersers. In addition, flowers are more conspicuous to pollinators than to seed dispersers and the reverse for fruits. Thus, despite marked differences in the visual systems of mutualists, flower and fruit colours have evolved to attract multiple, distinct mutualists but not unintended perceivers. We show that this adaptation is facilitated by a limited correlation between flower and fruit colours, and by the fact that colour signals as coded at the photoreceptor level are more similar within than between functional groups (pollinators and seed dispersers). Overall, these results provide the first quantitative demonstration that flower and fruit colours are adaptations allowing plants to communicate simultaneously with distinct groups of mutualists. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  17. Standing genetic variation in host preference for mutualist microbial symbionts.

    Science.gov (United States)

    Simonsen, Anna K; Stinchcombe, John R

    2014-12-22

    Many models of mutualisms show that mutualisms are unstable if hosts lack mechanisms enabling preferential associations with mutualistic symbiotic partners over exploitative partners. Despite the theoretical importance of mutualism-stabilizing mechanisms, we have little empirical evidence to infer their evolutionary dynamics in response to exploitation by non-beneficial partners. Using a model mutualism-the interaction between legumes and nitrogen-fixing soil symbionts-we tested for quantitative genetic variation in plant responses to mutualistic and exploitative symbiotic rhizobia in controlled greenhouse conditions. We found significant broad-sense heritability in a legume host's preferential association with mutualistic over exploitative symbionts and selection to reduce frequency of associations with exploitative partners. We failed to detect evidence that selection will favour the loss of mutualism-stabilizing mechanisms in the absence of exploitation, as we found no evidence for a fitness cost to the host trait or indirect selection on genetically correlated traits. Our results show that genetic variation in the ability to preferentially reduce associations with an exploitative partner exists within mutualisms and is under selection, indicating that micro-evolutionary responses in mutualism-stabilizing traits in the face of rapidly evolving mutualistic and exploitative symbiotic bacteria can occur in natural host populations. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  18. Experimental Study of Factors Affecting Soil Erodibility

    Science.gov (United States)

    Larionov, G. A.; Bushueva, O. G.; Gorobets, A. V.; Dobrovolskaya, N. G.; Kiryukhina, Z. P.; Krasnov, S. F.; Litvin, L. F.; Maksimova, I. A.; Sudnitsyn, I. I.

    2018-03-01

    The effect of different factors and preparation conditions of monofraction samples from the arable horizon of leached chernozem on soil erodibility and its relationship with soil tensile strength (STS) has been studied. The exposure of samples at 38°C reduces their erodibility by two orders of magnitude. The drying of samples, on the contrary, increases their erodibility. It has been shown that erodibility decreases during the experiment. It has been found that the inoculation of soil with yeast cultures ( Naganishia albida, Lipomyces tetrasporus) reliably increases the STS value in 1.5-1.9 times. The sterile soil is eroded more intensively than the unsterile soil: at 4.9 and 0.3 g/(m2 s), respectively. The drying of soil followed by wetting to the initial water content (30%) has no significant effect on the STS value in almost all experimental treatments.

  19. Specialization of mutualistic interaction networks decreases toward tropical latitudes

    DEFF Research Database (Denmark)

    Schleuning, M.; Fründ, J.; Klein, A.-M.

    2012-01-01

    that current conditions have a stronger effect on biotic specialization than historical community stability. Biotic specialization decreased with increasing local and regional plant diversity. This suggests that high specialization of mutualistic interactions is a response of pollinators and seed dispersers......] or differences in plant diversity [10, 11]. Thus, the direction of the latitudinal specialization gradient remains contentious. With an unprecedented global data set, we investigated how biotic specialization between plants and animal pollinators or seed dispersers is associated with latitude, past...... and contemporary climate, and plant diversity. We show that in contrast to expectation, biotic specialization of mutualistic networks is significantly lower at tropical than at temperate latitudes. Specialization was more closely related to contemporary climate than to past climate stability, suggesting...

  20. Non Standard Finite Difference Scheme for Mutualistic Interaction Description

    OpenAIRE

    Gabbriellini, Gianluca

    2012-01-01

    One of the more interesting themes of the mathematical ecology is the description of the mutualistic interaction between two interacting species. Based on continuous-time model developed by Holland and DeAngelis 2009 for consumer-resource mutualism description, this work deals with the application of the Mickens Non Standard Finite Difference method to transform the continuous-time scheme into a discrete-time one. It has been proved that the Mickens scheme is dynamically consistent with the o...

  1. Root signals that mediate mutualistic interactions in the rhizosphere.

    Science.gov (United States)

    Rasmann, Sergio; Turlings, Ted Cj

    2016-08-01

    A recent boom in research on belowground ecology is rapidly revealing a multitude of fascinating interactions, in particular in the rhizosphere. Many of these interactions are mediated by photo-assimilates that are excreted by plant roots. Root exudates are not mere waste products, but serve numerous functions to control abiotic and biotic processes. These functions range from changing the chemical and physical properties of the soil, inhibiting the growth of competing plants, combatting herbivores, and regulating the microbial community. Particularly intriguing are root-released compounds that have evolved to serve mutualistic interactions with soil-dwelling organisms. These mutually beneficial plant-mediated signals are not only of fundamental ecological interest, but also exceedingly important from an agronomical perspective. Here, we attempt to provide an overview of the plant-produced compounds that have so far been implicated in mutualistic interactions. We propose that these mutualistic signals may have evolved from chemical defenses and we point out that they can be (mis)used by specialized pathogens and herbivores. We speculate that many more signals and interactions remain to be uncovered and that a good understanding of the mechanisms and ecological implications can be the basis for exploitation and manipulation of the signals for crop improvement and protection. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Reaction of mutualistic and granivorous ants to ulex elaiosome chemicals.

    Science.gov (United States)

    Gammans, Nicola; Bullock, James M; Gibbons, Hannah; Schönrogge, Karsten

    2006-09-01

    It has been proposed that chemicals on plant elaiosomes aid seed detection by seed-dispersing ants. We hypothesized that the chemical interaction between ants and elaiosomes is more intimate than a generic attraction, and that elaiosome chemicals will attract mutualistic but not granivorous ant species. We investigated this by using two gorse species, Ulex minor and U. europaeus, and two associated ant species from European heathlands, the mutualist Myrmica ruginodis and the granivore Tetramorium caespitum. Behavioral studies were conducted with laboratory nests and foraging arenas. Both ants will take Ulex seeds, but while M. ruginodis showed increased antennation toward ether extracts of elaiosome surface chemicals compared with controls, T. caespitum showed no response. Elaiosome extracts were separated into seven lipid fractions. M. ruginodis showed increased antennation only toward the diglyceride fractions of both Ulex species, whereas T. caespitum showed no consistent reaction. This indicates that M. ruginodis can detect the elaiosome by responding to its surface chemicals, but T. caespitum is unresponsive to these chemicals. Responses to surface chemicals could increase the rate of seed detection in the field, and so these results suggest that Ulex elaiosomes produce chemicals that facilitate attraction of mutualistic rather than granivorous ant species. This could reduce seed predation and increase Ulex fitness.

  3. Spatial dynamics of synthetic microbial mutualists and their parasites.

    Directory of Open Access Journals (Sweden)

    Daniel R Amor

    2017-08-01

    Full Text Available A major force contributing to the emergence of novelty in nature is the presence of cooperative interactions, where two or more components of a system act in synergy, sometimes leading to higher-order, emergent phenomena. Within molecular evolution, the so called hypercycle defines the simplest model of an autocatalytic cycle, providing major theoretical insights on the evolution of cooperation in the early biosphere. These closed cooperative loops have also inspired our understanding of how catalytic loops appear in ecological systems. In both cases, hypercycle and ecological cooperative loops, the role played by space seems to be crucial for their stability and resilience against parasites. However, it is difficult to test these ideas in natural ecosystems, where time and spatial scales introduce considerable limitations. Here, we use engineered bacteria as a model system to a variety of environmental scenarios identifying trends that transcend the specific model system, such an enhanced genetic diversity in environments requiring mutualistic interactions. Interestingly, we show that improved environments can slow down mutualistic range expansions as a result of genetic drift effects preceding local resource depletion. Moreover, we show that a parasitic strain is excluded from the population during range expansions (which acknowledges a classical prediction. Nevertheless, environmental deterioration can reshape population interactions, this same strain becoming part of a three-species mutualistic web in scenarios in which the two-strain mutualism becomes non functional. The evolutionary and ecological implications for the design of synthetic ecosystems are outlined.

  4. Linking nutrient enrichment, sediment erodibility and biofilms

    Science.gov (United States)

    Conrad, B.; Mahon, R.; Sojka, S. L.

    2014-12-01

    Sediment movement in coastal lagoons affects nutrient flux and primary producer growth. Previous research has shown that sediment erodibility is affected by biofilm concentration and that growth of benthic organisms, which produce biofilm, is affected by nutrient enrichment. However, researchers have not examined possible links between nutrient addition and sediment erodibility. We manipulated nutrient levels in the water column of 16 microcosms filled with homogenized sediment from a shallow coastal lagoon and artificial seawater to determine the effects on biofilm growth, measured through chlorophyll a and colloidal carbohydrate concentrations. Erosion tests using a Gust microcosm were conducted to determine the relationship between sediment erodibility and biofilm concentration. Results show that carbohydrate levels decreased with increasing nutrient enrichment and were unrelated to chlorophyll concentrations and erodibility. The nutrient levels did not predictably affect the chlorophyll levels, with lower chlorophyll concentrations in the control and medium enrichment treatments than the low and high enrichment treatments. Controls on biofilm growth are still unclear and the assumed relationship between carbohydrates and erodibility may be invalid. Understanding how biofilms respond to nutrient enrichment and subsequent effects on sediment erodibility is essential for protecting and restoring shallow coastal systems.

  5. Can Fertilization of Soil Select Less Mutualistic Mycorrhizae?

    Science.gov (United States)

    Johnson, Nancy Collins

    1993-11-01

    It has been noted previously that nutrient-stressed plants generally release more soluble carbohydrate in root exudates and consequently support more mycorrhizae than plants supplied with ample nutrients. Fertilization may select strains of vesicular-arbuscular mycorrhizal (VAM) fungi that are inferior mutualists if the same characteristics that make a VAM fungus successful in roots with a lowered carbohydrate content also reduce the benefits that the fungus provides a host plant. This two-phase study experimentally tests the hypothesis that fertilizing low-nutrient soil selects VAM fungi that are inferior mutualists. The first phase examines the effects of chemical fertilizers on the species composition of VAM fungal communities in long-term field plots. The second phase measures the effects of VAM fungal assemblages from fertilized and unfertilized plots on big bluestem grass grown in a greenhouse. The field results indicate that 8 yr of fertilization altered the species composition of VAM fungal communities. Relative abundance of Gigaspora gigantea, Gigaspora margarita, Scutellispora calospora, and Glomus occultum decreased while Glomus intraradix increased in response to fertilization. Results from the greenhouse experiment show that big bluestem colonized with VAM fungi from fertilized soil were smaller after 1 mo and produced fewer inflorescences at 3 mo than big bluestem colonized with VAM fungi from unfertilized soil. Fungal structures within big bluestem roots suggest that VAM fungi from fertilized soil exerted a higher net carbon cost on their host than VAM fungi from unfertilized soil. VAM fungi from fertilized soil produced fewer hyphae and arbuscules (and consequently provided their host with less inorganic nutrients from the soil) and produced as many vesicles (and thus provisioned their own storage structures at the same level) as fungi from unfertilized soil. These results support the hypothesis that fertilization selects VAM fungi that are inferior

  6. Rethinking the logistic approach for population dynamics of mutualistic interactions.

    Science.gov (United States)

    García-Algarra, Javier; Galeano, Javier; Pastor, Juan Manuel; Iriondo, José María; Ramasco, José J

    2014-12-21

    Mutualistic communities have an internal structure that makes them resilient to external perturbations. Late research has focused on their stability and the topology of the relations between the different organisms to explain the reasons of the system robustness. Much less attention has been invested in analyzing the systems dynamics. The main population models in use are modifications of the r-K formulation of logistic equation with additional terms to account for the benefits produced by the interspecific interactions. These models have shortcomings as the so-called r-K formulation diverges under some conditions. In this work, we introduce a model for population dynamics under mutualism that preserves the original logistic formulation. It is mathematically simpler than the widely used type II models, although it shows similar complexity in terms of fixed points and stability of the dynamics. We perform an analytical stability analysis and numerical simulations to study the model behavior in general interaction scenarios including tests of the resilience of its dynamics under external perturbations. Despite its simplicity, our results indicate that the model dynamics shows an important richness that can be used to gain further insights in the dynamics of mutualistic communities. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Dispersive and erodible soils - fundamental differences

    CSIR Research Space (South Africa)

    Paige-Green, P

    2008-11-01

    Full Text Available Dispersive, erodible and slaking soils are prevalent over wide areas of South Africa. Each of these materials increases the cost of construction, but dispersive soils are likely to lead to far more serious problems, particularly in dam construction...

  8. Journal entries facilitating preprofessional scientific literacy and mutualistic symbiotic relationships

    Science.gov (United States)

    Vander Vliet, Valerie J.

    This study explored journal writing as an alternative assessment to promote the development of pre-professional scientific literacy and mutualistic symbiotic relationships between teaching and learning, instruction and assessment, and students and teachers. The larger context of this study is an action reaction project of the attempted transformation of a traditional first year undergraduate pre-professional biology class to sociocultural constructivist principles. The participants were commuter and residential, full and part-time students ranging in age from 18 to 27 and 18/21 were female. The backgrounds of the students varied considerably, ranging from low to upper middle income, including students of Black and Asian heritage. The setting was a medium-sized Midwestern university. The instructor has twenty years of experience teaching Biology at the college level. The data were analyzed using the constant comparative method and the development of grounded theory. The journal entries were analyzed as to their function and form in relationship to the development of multiple aspects of pre-professional scientific literacy. The perceptions of the students as to the significance of the use of journal entries were also determined through the analysis of their use of journal entries in their portfolios and statements in surveys and portfolios. The analysis revealed that journal entries promoted multiple aspects of pre-professional scientific literacy in both students and the instructor and facilitated the development of mutualistic symbiotic relationships between teaching and learning, instruction and assessment, and students and teachers. The function analysis revealed that the journal entries fulfilled the functions intended for the development of multiple aspects of pre-professional scientific literacy. The complexity of journal writing emerged from the form analysis, which revealed the multiple form elements inherent in journal entries. Students perceived journal

  9. Morphodynamic modeling of erodible laminar channels.

    Science.gov (United States)

    Devauchelle, Olivier; Josserand, Christophe; Lagrée, Pierre-Yves; Zaleski, Stéphane

    2007-11-01

    A two-dimensional model for the erosion generated by viscous free-surface flows, based on the shallow-water equations and the lubrication approximation, is presented. It has a family of self-similar solutions for straight erodible channels, with an aspect ratio that increases in time. It is also shown, through a simplified stability analysis, that a laminar river can generate various bar instabilities very similar to those observed in natural rivers. This theoretical similarity reflects the meandering and braiding tendencies of laminar rivers indicated by F. Métivier and P. Meunier [J. Hydrol. 27, 22 (2003)]. Finally, we propose a simple scenario for the transition between patterns observed in experimental erodible channels.

  10. Unifying relationships between complexity and stability in mutualistic ecological communities.

    Science.gov (United States)

    Feng, Wenfeng; Bailey, Richard M

    2018-02-14

    Conserving ecosystem function and associated services requires deep understanding of the underlying basis of system stability. While the study of ecological dynamics is a mature and diverse field, the lack of a general model that predicts a broad range of theoretical and empirical observations has allowed unresolved contradictions to persist. Here we provide a general model of mutualistic ecological interactions between two groups and show for the first time how the conditions for bi-stability, the nature of critical transitions, and identifiable leading indicators in time-series can be derived from the basic parameters describing the underlying ecological interactions. Strong mutualism and nonlinearity in handling-time are found to be necessary conditions for the occurrence of critical transitions. We use the model to resolve open questions concerning the effects of heterogeneity in inter-species interactions on both resilience and abundance, and discuss these in terms of potential trade-offs in real systems. This framework provides a basis for rich investigations of ecological system dynamics, and may be generalizable across many ecological contexts. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Soil erodibility for water erosion: A perspective and Chinese experiences

    Science.gov (United States)

    Wang, Bin; Zheng, Fenli; Römkens, Mathias J. M.; Darboux, Frédéric

    2013-04-01

    Knowledge of soil erodibility is an essential requirement for erosion prediction, conservation planning, and the assessment of sediment related environmental effects of watershed agricultural practices. This paper reviews the status of soil erodibility evaluations and determinations based on 80 years of upland area erosion research mainly in China and the USA. The review synthesizes the general research progress made by discussing the basic concepts of erodibility and its evaluation, determination, and prediction as well as knowledge of its spatio-temporal variations. The authors found that soil erodibility is often inappropriately or inaccurately applied in describing soil loss caused by different soil erosion component processes and mechanisms. Soil erodibility indicators were related to intrinsic soil properties and exogenic erosional forces, measurements, and calculations. The present review describes major needs including: (1) improved definition of erodibility, (2) modified erodibility determinations in erosion models, especially for specific geographical locations and in the context of different erosion sub-processes, (3) advanced methodologies for quantifying erodibilities of different soil erosion sub-processes, and (4) a better understanding of the mechanism that causes temporal variations in soil erodibility. The review also provides a more rational basis for future research on soil erodibility and supports predictive modeling of soil erosion processes and the development of improved conservation practices.

  12. Quality Uncertainty Erodes Trust in Science

    Directory of Open Access Journals (Sweden)

    Simine Vazire

    2017-02-01

    Full Text Available When consumers of science (readers and reviewers lack relevant details about the study design, data, and analyses, they cannot adequately evaluate the strength of a scientific study. Lack of transparency is common in science, and is encouraged by journals that place more emphasis on the aesthetic appeal of a manuscript than the robustness of its scientific claims. In doing this, journals are implicitly encouraging authors to do whatever it takes to obtain eye-catching results. To achieve this, researchers can use common research practices that beautify results at the expense of the robustness of those results (e.g., p-hacking. The problem is not engaging in these practices, but failing to disclose them. A car whose carburetor is duct-taped to the rest of the car might work perfectly fine, but the buyer has a right to know about the duct-taping. Without high levels of transparency in scientific publications, consumers of scientific manuscripts are in a similar position as buyers of used cars – they cannot reliably tell the difference between lemons and high quality findings. This phenomenon – quality uncertainty – has been shown to erode trust in economic markets, such as the used car market. The same problem threatens to erode trust in science. The solution is to increase transparency and give consumers of scientific research the information they need to accurately evaluate research. Transparency would also encourage researchers to be more careful in how they conduct their studies and write up their results. To make this happen, we must tie journals’ reputations to their practices regarding transparency. Reviewers hold a great deal of power to make this happen, by demanding the transparency needed to rigorously evaluate scientific manuscripts. The public expects transparency from science, and appropriately so – we should be held to a higher standard than used car salespeople.

  13. Eroded Layered Material in Southwest Utopia Planitia

    Science.gov (United States)

    1999-01-01

    Images from the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC)dramatically illustrate that many places on the red planet have outcrops of layered geologic materials. The two pictures above show the remains of layered material inside craters in southwestern Utopia Planitia (see inset for detailed view). These remnant layers indicate that the craters--and perhaps the plains that surround them--were once buried beneath a deposit that has since been eroded away. This theme of layered outcrops and exhumed craters appears to be one of the dominant observations that MGS MOC has made--to date--about Mars. The origin and composition of the layered material--and its ultimate fate once it was largely eroded away--are unknown. Each of the two pictures shown here covers an area about 4 kilometers (2.5 miles)by 6.3 kilometers (3.9 miles). Illumination is from the lower right. These are subframes of a single MOC image acquired in July 1998 during the MGS Science Phasing Orbits imaging campaign. This figure was presented at the 30th Lunar and Planetary Science Conference in Houston, Texas, March 1999. Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

  14. Multiple mutualist effects on genomewide expression in the tripartite association between Medicago truncatula, nitrogen-fixing bacteria and mycorrhizal fungi.

    Science.gov (United States)

    Afkhami, Michelle E; Stinchcombe, John R

    2016-10-01

    While all species interact with multiple mutualists, the fitness consequences and molecular mechanisms underlying these interactions remain largely unknown. We combined factorial ecological experiments with genomewide expression analyses to examine the phenotypic and transcriptomic responses of model legume Medicago truncatula to rhizobia and mycorrhizal fungi. We found synergistic effects of these mutualists on plant performance and examined unique features of plant gene expression responses to multiple mutualists. There were genomewide signatures of mutualists and multiple mutualists on expression, with partners often affecting unique sets of genes. Mycorrhizal fungi had stronger effects on plant expression than rhizobia, with 70% of differentially expressed genes affected by fungi. Fungal and bacterial mutualists had joint effects on 10% of differentially expressed genes, including unexpected, nonadditive effects on some genes with important functions such as nutrient metabolism. For a subset of genes, interacting with multiple mutualists even led to reversals in the direction of expression (shifts from up to downregulation) compared to interacting with single mutualists. Rhizobia also affected the expression of several mycorrhizal genes, including those involved in nutrient transfer to host plants, indicating that partner species can also impact each other's molecular phenotypes. Collectively, these data illustrate the diverse molecular mechanisms and transcriptional responses associated with the synergistic benefits of multiple mutualists. © 2016 John Wiley & Sons Ltd.

  15. Surgical excision of eroded mesh after prior abdominal sacrocolpopexy.

    Science.gov (United States)

    South, Mary M T; Foster, Raymond T; Webster, George D; Weidner, Alison C; Amundsen, Cindy L

    2007-12-01

    months. Seven patients ultimately required abdominal excision and all had symptom resolution, however, not without complications. Two patients had bowel injury during lysis of adhesions requiring bowel resection in 1 case and repair in another, 1 had a postoperative wound infection with breakdown, 1 was readmitted for postoperative fever requiring antibiotics, and 1 had an acute coronary syndrome requiring transfer to the cardiology service. Transvaginal excision of mesh with or without endoscopy appears to be a safe and less invasive method for excision of eroded vaginal mesh after prior abdominal sacrocolpopexy. Up to 3 vaginal excision attempts may be necessary to achieve symptom resolution, and complete removal of mesh will likely improve outcomes with the transvaginal technique. Although abdominal excision can be considered the gold standard for excision of eroded mesh, it is not without potentially increased morbidity.

  16. Mixed infections may promote diversification of mutualistic symbionts: why are there ineffective rhizobia?

    Science.gov (United States)

    Friesen, M L; Mathias, A

    2010-02-01

    While strategy variation is a key feature of symbiotic mutualisms, little work focuses on the origin of this diversity. Rhizobia strategies range from mutualistic nitrogen fixers to parasitic nonfixers that hoard plant resources to increase their own survival in soil. Host plants reward beneficial rhizobia with higher nodule growth rates, generating a trade-off between reproduction in nodules and subsequent survival in soil. However, hosts might not discriminate between strains in mixed infections, allowing nonfixing strains to escape sanctions. We construct an adaptive dynamics model of symbiotic nitrogen-fixation and find general situations where symbionts undergo adaptive diversification, but in most situations complete nonfixers do not evolve. Social conflict in mixed infections when symbionts face a survival-reproduction trade-off can drive the origin of some coexisting symbiont strategies, where less mutualistic strains exploit benefits generated by better mutualists.

  17. Resilient networks of ant-plant mutualists in Amazonian forest fragments.

    Science.gov (United States)

    Passmore, Heather A; Bruna, Emilio M; Heredia, Sylvia M; Vasconcelos, Heraldo L

    2012-01-01

    The organization of networks of interacting species, such as plants and animals engaged in mutualisms, strongly influences the ecology and evolution of partner communities. Habitat fragmentation is a globally pervasive form of spatial heterogeneity that could profoundly impact the structure of mutualist networks. This is particularly true for biodiversity-rich tropical ecosystems, where the majority of plant species depend on mutualisms with animals and it is thought that changes in the structure of mutualist networks could lead to cascades of extinctions. We evaluated effects of fragmentation on mutualistic networks by calculating metrics of network structure for ant-plant networks in continuous Amazonian forests with those in forest fragments. We hypothesized that networks in fragments would have fewer species and higher connectance, but equal nestedness and resilience compared to forest networks. Only one of the nine metrics we compared differed between continuous forest and forest fragments, indicating that networks were resistant to the biotic and abiotic changes that accompany fragmentation. This is partially the result of the loss of only specialist species with one connection that were lost in forest fragments. We found that the networks of ant-plant mutualists in twenty-five year old fragments are similar to those in continuous forest, suggesting these interactions are resistant to the detrimental changes associated with habitat fragmentation, at least in landscapes that are a mosaic of fragments, regenerating forests, and pastures. However, ant-plant mutualistic networks may have several properties that may promote their persistence in fragmented landscapes. Proactive identification of key mutualist partners may be necessary to focus conservation efforts on the interactions that insure the integrity of network structure and the ecosystems services networks provide.

  18. Resilient networks of ant-plant mutualists in Amazonian forest fragments.

    Directory of Open Access Journals (Sweden)

    Heather A Passmore

    Full Text Available The organization of networks of interacting species, such as plants and animals engaged in mutualisms, strongly influences the ecology and evolution of partner communities. Habitat fragmentation is a globally pervasive form of spatial heterogeneity that could profoundly impact the structure of mutualist networks. This is particularly true for biodiversity-rich tropical ecosystems, where the majority of plant species depend on mutualisms with animals and it is thought that changes in the structure of mutualist networks could lead to cascades of extinctions.We evaluated effects of fragmentation on mutualistic networks by calculating metrics of network structure for ant-plant networks in continuous Amazonian forests with those in forest fragments. We hypothesized that networks in fragments would have fewer species and higher connectance, but equal nestedness and resilience compared to forest networks. Only one of the nine metrics we compared differed between continuous forest and forest fragments, indicating that networks were resistant to the biotic and abiotic changes that accompany fragmentation. This is partially the result of the loss of only specialist species with one connection that were lost in forest fragments.We found that the networks of ant-plant mutualists in twenty-five year old fragments are similar to those in continuous forest, suggesting these interactions are resistant to the detrimental changes associated with habitat fragmentation, at least in landscapes that are a mosaic of fragments, regenerating forests, and pastures. However, ant-plant mutualistic networks may have several properties that may promote their persistence in fragmented landscapes. Proactive identification of key mutualist partners may be necessary to focus conservation efforts on the interactions that insure the integrity of network structure and the ecosystems services networks provide.

  19. Unravelling Darwin's entangled bank: architecture and robustness of mutualistic networks with multiple interaction types.

    Science.gov (United States)

    Dáttilo, Wesley; Lara-Rodríguez, Nubia; Jordano, Pedro; Guimarães, Paulo R; Thompson, John N; Marquis, Robert J; Medeiros, Lucas P; Ortiz-Pulido, Raul; Marcos-García, Maria A; Rico-Gray, Victor

    2016-11-30

    Trying to unravel Darwin's entangled bank further, we describe the architecture of a network involving multiple forms of mutualism (pollination by animals, seed dispersal by birds and plant protection by ants) and evaluate whether this multi-network shows evidence of a structure that promotes robustness. We found that species differed strongly in their contributions to the organization of the multi-interaction network, and that only a few species contributed to the structuring of these patterns. Moreover, we observed that the multi-interaction networks did not enhance community robustness compared with each of the three independent mutualistic networks when analysed across a range of simulated scenarios of species extinction. By simulating the removal of highly interacting species, we observed that, overall, these species enhance network nestedness and robustness, but decrease modularity. We discuss how the organization of interlinked mutualistic networks may be essential for the maintenance of ecological communities, and therefore the long-term ecological and evolutionary dynamics of interactive, species-rich communities. We suggest that conserving these keystone mutualists and their interactions is crucial to the persistence of species-rich mutualistic assemblages, mainly because they support other species and shape the network organization. © 2016 The Author(s).

  20. igh Symbiont Relatedness Stabilizes Mutualistic Cooperation in Fungus-Growing Termites

    NARCIS (Netherlands)

    Aanen, D.K.; Fine Licht, De H.H.; Debets, A.J.M.; Kerstes, N.A.G.; Hoekstra, R.F.; Boomsma, J.J.

    2009-01-01

    It is unclear how mutualistic relationships can be stable when partners disperse freely and have the possibility of forming associations with many alternative genotypes. Theory predicts that high symbiont relatedness should resolve this problem, but the mechanisms to enforce this have rarely been

  1. Effects of dam-induced landscape fragmentation on amazonian ant-plant mutualistic networks.

    Science.gov (United States)

    Emer, Carine; Venticinque, Eduardo Martins; Fonseca, Carlos Roberto

    2013-08-01

    Mutualistic networks are critical to biological diversity maintenance; however, their structures and functionality may be threatened by a swiftly changing world. In the Amazon, the increasing number of dams poses a large threat to biological diversity because they greatly alter and fragment the surrounding landscape. Tight coevolutionary interactions typical of tropical forests, such as the ant-myrmecophyte mutualism, where the myrmecophyte plants provide domatia nesting space to their symbiotic ants, may be jeopardized by the landscape changes caused by dams. We analyzed 31 ant-myrmecophyte mutualistic networks in undisturbed and disturbed sites surrounding Balbina, the largest Central Amazonian dam. We tested how ant-myrmecophyte networks differ among dam-induced islands, lake edges, and undisturbed forests in terms of species richness, composition, structure, and robustness (number of species remaining in the network after partner extinctions). We also tested how landscape configuration in terms of area, isolation, shape, and neighborhood alters the structure of the ant-myrmecophyte networks on islands. Ant-myrmecophytic networks were highly compartmentalized in undisturbed forests, and the compartments had few strongly connected mutualistic partners. In contrast, networks at lake edges and on islands were not compartmentalized and were negatively affected by island area and isolation in terms of species richness, density, and composition. Habitat loss and fragmentation led to coextinction cascades that contributed to the elimination of entire ant-plant compartments. Furthermore, many myrmecophytic plants in disturbed sites lost their mutualistic ant partners or were colonized by opportunistic, nonspecialized ants. Robustness of ant-myrmecophyte networks on islands was lower than robustness near lake edges and in undisturbed forest and was particularly susceptible to the extinction of plants. Beyond the immediate habitat loss caused by the building of large dams

  2. U.S.V.I. Soil Erodibility (Kffact)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — U.S.V.I. soil erodibility (Kffactor) - low values indicate low vulnerability to erosion, higher values mean higher susceptibility to runoff.

  3. Soil erodibility variability in laboratory and field rainfall simulations

    Science.gov (United States)

    Szabó, Boglárka; Szabó, Judit; Jakab, Gergely; Centeri, Csaba; Szalai, Zoltán

    2017-04-01

    Rainfall simulation experiments are the most common way to observe and to model the soil erosion processes in in situ and ex situ circumstances. During modelling soil erosion, one of the most important factors are the annual soil loss and the soil erodibility which represent the effect of soil properties on soil loss and the soil resistance against water erosion. The amount of runoff and soil loss can differ in case of the same soil type, while it's characteristics determine the soil erodibility factor. This leads to uncertainties regarding soil erodibility. Soil loss and soil erodibility were examined with the investigation of the same soil under laboratory and field conditions with rainfall simulators. The comparative measurement was carried out in a laboratory on 0,5 m2, and in the field (Shower Power-02) on 6 m2 plot size where the applied slope angles were 5% and 12% with 30 and 90 mm/h rainfall intensity. The main idea was to examine and compare the soil erodibility and its variability coming from the same soil, but different rainfall simulator type. The applied model was the USLE, nomograph and other equations which concern single rainfall events. The given results show differences between the field and laboratory experiments and between the different calculations. Concerning for the whole rainfall events runoff and soil loss, were significantly higher at the laboratory experiments, which affected the soil erodibility values too. The given differences can originate from the plot size. The main research questions are that: How should we handle the soil erodibility factors and its significant variability? What is the best solution for soil erodibility determination?

  4. Robotic removal of eroded vaginal mesh into the bladder.

    Science.gov (United States)

    Macedo, Francisco Igor B; O'Connor, Jeffrey; Mittal, Vijay K; Hurley, Patrick

    2013-11-01

    Vaginal mesh erosion into the bladder after midurethral sling procedure or cystocele repair is uncommon, with only a few cases having been reported in the literature. The ideal surgical management is still controversial. Current options for removal of eroded mesh include: endoscopic, transvaginal or abdominal (either open or laparoscopic) approaches. We, herein, present the first case of robotic removal of a large eroded vaginal mesh into the bladder and discuss potential benefits and limitations of the technique. © 2013 The Japanese Urological Association.

  5. Ants use partner specific odors to learn to recognize a mutualistic partner.

    Directory of Open Access Journals (Sweden)

    Masaru K Hojo

    Full Text Available Regulation via interspecific communication is an important for the maintenance of many mutualisms. However, mechanisms underlying the evolution of partner communication are poorly understood for many mutualisms. Here we show, in an ant-lycaenid butterfly mutualism, that attendant ants selectively learn to recognize and interact cooperatively with a partner. Workers of the ant Pristomyrmex punctatus learn to associate cuticular hydrocarbons of mutualistic Narathura japonica caterpillars with food rewards and, as a result, are more likely to tend the caterpillars. However, the workers do not learn to associate the cuticular hydrocarbons of caterpillars of a non-ant-associated lycaenid, Lycaena phlaeas, with artificial food rewards. Chemical analysis revealed cuticular hydrocarbon profiles of the mutualistic caterpillars were complex compared with those of non-ant-associated caterpillars. Our results suggest that partner-recognition based on partner-specific chemical signals and cognitive abilities of workers are important mechanisms underlying the evolution and maintenance of mutualism with ants.

  6. Bears benefit plants via a cascade with both antagonistic and mutualistic interactions.

    Science.gov (United States)

    Grinath, Joshua B; Inouye, Brian D; Underwood, Nora

    2015-02-01

    Predators can influence primary producers by generating cascades of effects in ecological webs. These effects are often non-intuitive, going undetected because they involve many links and different types of species interactions. Particularly, little is understood about how antagonistic (negative) and mutualistic (positive) interactions combine to create cascades. Here, we show that black bears can benefit plants by consuming ants. The ants are mutualists of herbivores and protect herbivores from other arthropod predators. We found that plants near bear-damaged ant nests had greater reproduction than those near undamaged nests, due to weaker ant protection for herbivores, which allowed herbivore suppression by arthropod predators. Our results highlight the need to integrate mutualisms into trophic cascade theory, which is based primarily on antagonistic relationships. Predators are often conservation targets, and our results suggest that bears and other predators should be managed with the understanding that they can influence primary producers through many paths. © 2014 John Wiley & Sons Ltd/CNRS.

  7. Et tu, Brute? Not Even Intracellular Mutualistic Symbionts Escape Horizontal Gene Transfer

    Directory of Open Access Journals (Sweden)

    Sergio López-Madrigal

    2017-09-01

    Full Text Available Many insect species maintain mutualistic relationships with endosymbiotic bacteria. In contrast to their free-living relatives, horizontal gene transfer (HGT has traditionally been considered rare in long-term endosymbionts. Nevertheless, meta-omics exploration of certain symbiotic models has unveiled an increasing number of bacteria-bacteria and bacteria-host genetic transfers. The abundance and function of transferred loci suggest that HGT might play a major role in the evolution of the corresponding consortia, enhancing their adaptive value or buffering detrimental effects derived from the reductive evolution of endosymbionts’ genomes. Here, we comprehensively review the HGT cases recorded to date in insect-bacteria mutualistic consortia, and discuss their impact on the evolutionary success of these associations.

  8. Specificity of the mutualistic association between actinomycete bacteria and two sympatric species of Acromyrmex leaf-cutting ants

    DEFF Research Database (Denmark)

    Poulsen, M; Cafaro, M; Boomsma, J J

    2005-01-01

    Acromyrmex leaf-cutting ants maintain two highly specialized, vertically transmitted mutualistic ectosymbionts: basidiomycete fungi that are cultivated for food in underground gardens and actinomycete Pseudonocardia bacteria that are reared on the cuticle to produce antibiotics that suppress...

  9. Delay-Induced Oscillations in a Competitor-Competitor-Mutualist Lotka-Volterra Model

    Directory of Open Access Journals (Sweden)

    Changjin Xu

    2017-01-01

    Full Text Available This paper deals with a competitor-competitor-mutualist Lotka-Volterra model. A series of sufficient criteria guaranteeing the stability and the occurrence of Hopf bifurcation for the model are obtained. Several concrete formulae determine the properties of bifurcating periodic solutions by applying the normal form theory and the center manifold principle. Computer simulations are given to support the theoretical predictions. At last, biological meaning and a conclusion are presented.

  10. Effect of garlic mustard invasion on ectomycorrhizae in mature pine trees and pine seedlings

    Science.gov (United States)

    Lauren A. Carlson; Kelly D. McConnaughay; Sherri J. Morris

    2014-01-01

    Ectomycorrhizal fungi are mutualistic fungi that colonize the roots of many terrestrial plants. These fungi increase plant vigor by acquiring nutrients from the soil for their hosts in exchange for photosynthates. We studied the effect of garlic mustard (Alliaria petiolata) invasion on the density of ectomycorrhizal symbionts using two approaches. We...

  11. sessment of ground water contamination in Erode District, Tamilnadu

    African Journals Online (AJOL)

    A systematic study has been carried out to assess the water contamination and the effect of the tanneries and dyeing industries effluents on Erode District, Tamil Nadu. Ten (10) sampling locations were selected in and around industries. The water samples were collected from the selected sampling points. The samples ...

  12. Assessment of ground water contamination in Erode District ...

    African Journals Online (AJOL)

    admin

    A systematic study has been carried out to assess the water contamination and the effect of the tanneries and dyeing industries effluents on Erode District, Tamil Nadu. Ten (10) sampling locations were selected in and around industries. The water samples were collected from the selected sampling points. The samples ...

  13. Interrill and rill erodibility in the northern andean highlands

    NARCIS (Netherlands)

    Romero, C.; Stroosnijder, L.; Baigorria, G.A.

    2007-01-01

    There is a lack of quantitative information describing the physical processes causing soil erosion in the Andean Highlands, especially those related to interrill and rill erodibility factors. To assess how susceptible are soils to erosion in this region, field measurements of interrill (Ki) and rill

  14. Seasonal change of WEPP erodibility parameters on a fallow plot

    Science.gov (United States)

    D. K. McCool; S. Dun; J. Q. Wu; W. J. Elliot

    2011-01-01

    In cold regions, frozen soil has a significant influence on runoff and water erosion. Frozen soil can reduce infiltration capacity, and the freeze-thaw processes degrade soil cohesive strength and increase soil erodibility. In the Inland Pacific Northwest of the USA, major erosion events typically occur during winter from low-intensity rain, snowmelt, or both as frozen...

  15. High Symbiont Relatedness Stabilizes Mutualistic Cooperation in Fungus-Growing Termites

    DEFF Research Database (Denmark)

    Aanen, Duur K; de Fine Licht, Henrik H; Debets, Alfons J M

    2009-01-01

    It is unclear how mutualistic relationships can be stable when partners disperse freely and have the possibility of forming associations with many alternative genotypes. Theory predicts that high symbiont relatedness should resolve this problem, but the mechanisms to enforce this have rarely been...... of spore production in proportion to strain frequency. This positive reinforcement results in an exclusive lifetime association of each host colony with a single fungal symbiont and hinders the evolution of cheating. Our findings explain why vertical symbiont transmission in fungus-growing termites is rare...

  16. Advancing Understanding of Earthquakes by Drilling an Eroding Convergent Margin

    Science.gov (United States)

    von Huene, R.; Vannucchi, P.; Ranero, C. R.

    2010-12-01

    A program of IODP with great societal relevance is sampling and instrumenting the seismogenic zone. The zone generates great earthquakes that trigger tsunamis, and submarine slides thereby endangering coastal communities containing over sixty percent of the earth’s population. To asses and mitigate this endangerment it is urgent to advance understanding of fault dynamics that allows more timely anticipation of hazardous seismicity. Seismogenesis on accreting and eroding convergent plate boundaries apparently differ because of dissimilar materials along the interplate fault. As the history of instrumentally recorded earthquakes expands the difference becomes clearer. The more homogeneous clay, silt and sand subducted at accreting margins is associated with great earthquakes (M 9) whereas the fragmented upper plate rock that can dominate subducted material along an eroding margin plate interface is associated with many tsunamigenic earthquakes (Bilek, 2010). Few areas have been identified where the seismogenic zone can be reached with scientific drilling. In IODP accreting margins are studied on the NanTroSeize drill transect off Japan where the ultimate drilling of the seismogenic interface may occur by the end of IODP. The eroding Costa Rica margin will be studied in CRISP where a drill program will begin in 2011. The Costa Rican geophysical site survey will be complete with acquisition and processing of 3D seismic data in 2011 but the entire drilling will not be accomplished in IODP. It is appropriate that the accreting margin study be accomplished soon considering the indications of a pending great earthquake that will affect a country that has devoted enormous resources to IODP. However, understanding the erosional end-member is scientifically as important to an understanding of fault mechanics. Transoceanic tsunamis affect the entire Pacific rim where most subduction zones are eroding margins. The Costa Rican subduction zone is less complex operationally and

  17. Bonding stability of adhesive systems to eroded dentin

    Directory of Open Access Journals (Sweden)

    Janaina Barros CRUZ

    2015-01-01

    Full Text Available This in vitro study evaluated the immediate and 6 months microshear bond strength (µSBS of different adhesive systems to sound and eroded dentin. Sixty bovine incisors were embedded in acrylic resin and ground to obtain flat buccal dentin surfaces. Specimens were randomly allocated into two groups: sound dentin (immersion in artificial saliva and eroded dentin (erosive challenge following a pH cycling model comprising 4 ×/day Sprite Light® drink for 10 days. Then, specimens were reassigned according to the adhesive system: etch-and-rinse adhesive (Adper Single Bond, two-step self-etch system (Clearfil SE Bond, or one-step self-etch adhesive (Adper Easy One. Polyethylene tubes with an internal diameter of 0.76 mm were placed over pre-treated dentin and filled with resin composite (Z250. Half of the specimens were evaluated by the µSBS test after 24 h, and the other half 6 months later, after water storage at 37°C. Failure mode was evaluated using a stereomicroscope (400×. Data were analyzed by three-way repeated measures analysis of variance and Tukey’s post hoc tests (α = 0.05. After 6 months of water aging, marked reductions in µSBS values were observed, irrespective of the substrate. The µSBS values for eroded dentin were lower than those obtained for sound dentin. No difference in bonding effectiveness was observed among adhesive systems. For all groups, adhesive/mixed failure was observed. In conclusion, eroded dentin compromises the bonding quality of adhesive systems over time.

  18. Salt Efflorescence Effects on Soil Surface Erodibility and Dust Emissions

    Science.gov (United States)

    Van Pelt, R. S.; Zhang, G.

    2017-12-01

    Soluble salts resulting from weathering of geological materials often form surface crusts or efflorescences in areas with shallow saline groundwater. In many cases, the affected areas are susceptible to wind erosion due to their lack of protective vegetation and their flat topography. Fugitive dusts containing soluble salts affect the biogeochemistry of deposition regions and may result in respiratory irritation during transport. We created efflorescent crusts on soil trays by surface evaporation of single salt solutions and bombarded the resultant efflorescences with quartz abrader sand in a laboratory wind tunnel. Four replicate trays containing a Torrifluvent soil affected by one of nine salts commonly found in arid and semiarid streams were tested and the emissions were captured by an aspirated multi-stage deposition and filtering system. We found that in most cases the efflorescent crust reduced the soil surface erodibility but also resulted in the emission of salt rich dust. Two of the salts, sodium thiosulfate and calcium chloride, resulted in increased soil volume and erodibility. However, one of the calcium chloride replicates was tested after an outbreak of humid air caused hygroscopic wetting of the soil and it became indurated upon drying greatly decreasing the erodibility. Although saline affected soils are not used for agricultural production and degradation is not a great concern, the release of salt rich dust is an area of environmental concern and steps to control the dust emissions from affected soils should be developed. Future testing will utilize suites of salts found in streams of arid and semiarid regions.

  19. Biorock Electric Reefs Grow Back Severely Eroded Beaches in Months

    Directory of Open Access Journals (Sweden)

    Thomas J. F. Goreau

    2017-10-01

    Full Text Available Severely eroded beaches on low lying islands in Indonesia were grown back in a few months—believed to be a record—using an innovative method of shore protection, Biorock electric reef technology. Biorock shore protection reefs are growing limestone structures that get stronger with age and repair themselves, are cheaper than concrete or rock sea walls and breakwaters, and are much more effective at shore protection and beach growth. Biorock reefs are permeable, porous, growing, self-repairing structures of any size or shape, which dissipate wave energy by internal refraction, diffraction, and frictional dissipation. They do not cause reflection of waves like hard sea walls and breakwaters, which erodes the sand in front of, and then underneath, such structures, until they collapse. Biorock reefs stimulate settlement, growth, survival, and resistance to the environmental stress of all forms of marine life, restoring coral reefs, sea grasses, biological sand production, and fisheries habitat. Biorock reefs can grow back eroded beaches and islands faster than the rate of sea level rise, and are the most cost-effective method of shore protection and adaptation to global sea level rise for low lying islands and coasts.

  20. The role of asymmetric interactions on the effect of habitat destruction in mutualistic networks.

    Directory of Open Access Journals (Sweden)

    Guillermo Abramson

    Full Text Available Plant-pollinator mutualistic networks are asymmetric in their interactions: specialist plants are pollinated by generalist animals, while generalist plants are pollinated by a broad range involving specialists and generalists. It has been suggested that this asymmetric--or disassortative--assemblage could play an important role in determining the observed equal susceptibility of specialist and generalist plants under habitat destruction. At the core of the analysis of the phenomenon lies the observation that specialist plants, otherwise candidates to extinction, could cope with the disruption thanks to their interaction with a few generalist pollinators. We present a theoretical framework that supports this thesis. We analyze a dynamical model of a system of mutualistic plants and pollinators, subject to the destruction of their habitat. We analyze and compare two families of interaction topologies, ranging from highly assortative to highly disassortative ones, as well as real pollination networks. We found that several features observed in natural systems are predicted by the mathematical model. First, there is a tendency to increase the asymmetry of the network as a result of the extinctions. Second, an entropy measure of the differential susceptibility to extinction of specialist and generalist species show that they tend to balance when the network is disassortative. Finally, the disappearance of links in the network, as a result of extinctions, shows that specialist plants preserve more connections than the corresponding plants in an assortative system, enabling them to resist the disruption.

  1. Bacteria may contribute to distant species recognition in ant-aphid mutualistic relationships.

    Science.gov (United States)

    Fischer, Christophe Y; Detrain, Claire; Thonart, Philippe; Haubruge, Eric; Francis, Frédéric; Verheggen, François J; Lognay, Georges C

    2017-04-01

    Mutualistic interactions between ant and aphid species have been the subject of considerable historical and contemporary investigations, the primary benefits being cleaning and protection for the aphids and carbohydrate-rich honeydew for the ants. Questions remained, however, as to the volatile semiochemical factor influencing this relationship. A recent study highlighted the role of bacterial honeydew volatile compounds in ant attraction. Here, ant's ability to distantly discriminate 2 aphid species was investigated based on bacterial honeydew semiochemicals emissions using a two-way olfactometer. Both the mutualistic aphid Aphis fabae L. and the nonmyrmecophilous aphid Acyrthosiphon pisum Harris were found to be attractive for the ant Lasius niger L. The level of attraction was similar in both assays (control vs. one of the aphid species). However, when given a choice between these 2 aphid species, ants showed a significant preference for Aphis fabae. Honeydew volatiles, mostly from bacterial origins, are known to be a key element in ant attraction. Using the same olfactometry protocol, the relative attractiveness of volatiles emitted by honeydews collected from each aphid species and by bacteria isolated from each honeydew was investigated. Again, ants significantly preferred volatiles released by Aphis fabae honeydew and bacteria. This information suggests that microbial honeydew volatiles enable ants to distantly discriminate aphid species. These results strengthen the interest of studying the occurrence and potential impact of microorganisms in insect symbioses. © 2015 Institute of Zoology, Chinese Academy of Sciences.

  2. Ant aggression and evolutionary stability in plant-ant and plant-pollinator mutualistic interactions.

    Science.gov (United States)

    Oña, L; Lachmann, M

    2011-03-01

    Mutualistic partners derive a benefit from their interaction, but this benefit can come at a cost. This is the case for plant-ant and plant-pollinator mutualistic associations. In exchange for protection from herbivores provided by the resident ants, plants supply various kinds of resources or nests to the ants. Most ant-myrmecophyte mutualisms are horizontally transmitted, and therefore, partners share an interest in growth but not in reproduction. This lack of alignment in fitness interests between plants and ants drives a conflict between them: ants can attack pollinators that cross-fertilize the host plants. Using a mathematical model, we define a threshold in ant aggressiveness determining pollinator survival or elimination on the host plant. In our model we observed that, all else being equal, facultative interactions result in pollinator extinction for lower levels of ant aggressiveness than obligatory interactions. We propose that the capacity to discriminate pollinators from herbivores should not often evolve in ants, and when it does it will be when the plants exhibit limited dispersal in an environment that is not seed saturated so that each seed produced can effectively generate a new offspring or if ants acquire an extra benefit from pollination (e.g. if ants eat fruit). We suggest specific mutualism examples where these hypotheses can be tested empirically. © 2010 The Authors. Journal of Evolutionary Biology © 2010 European Society For Evolutionary Biology.

  3. A conceptual framework for studying the strength of plant-animal mutualistic interactions.

    Science.gov (United States)

    Vázquez, Diego P; Ramos-Jiliberto, Rodrigo; Urbani, Pasquinell; Valdovinos, Fernanda S

    2015-04-01

    The strength of species interactions influences strongly the structure and dynamics of ecological systems. Thus, quantifying such strength is crucial to understand how species interactions shape communities and ecosystems. Although the concepts and measurement of interaction strength in food webs have received much attention, there has been comparatively little progress in the context of mutualism. We propose a conceptual scheme for studying the strength of plant-animal mutualistic interactions. We first review the interaction strength concepts developed for food webs, and explore how these concepts have been applied to mutualistic interactions. We then outline and explain a conceptual framework for defining ecological effects in plant-animal mutualisms. We give recommendations for measuring interaction strength from data collected in field studies based on a proposed approach for the assessment of interaction strength in plant-animal mutualisms. This approach is conceptually integrative and methodologically feasible, as it focuses on two key variables usually measured in field studies: the frequency of interactions and the fitness components influenced by the interactions. © 2015 John Wiley & Sons Ltd/CNRS.

  4. No evidence for adaptation to local rhizobial mutualists in the legume Medicago lupulina.

    Science.gov (United States)

    Harrison, Tia L; Wood, Corlett W; Borges, Isabela L; Stinchcombe, John R

    2017-06-01

    Local adaptation is a common but not ubiquitous feature of species interactions, and understanding the circumstances under which it evolves illuminates the factors that influence adaptive population divergence. Antagonistic species interactions dominate the local adaptation literature relative to mutualistic ones, preventing an overall assessment of adaptation within interspecific interactions. Here, we tested whether the legume Medicago lupulina is adapted to the locally abundant species of mutualistic nitrogen-fixing rhizobial bacteria that vary in frequency across its eastern North American range. We reciprocally inoculated northern and southern M. lupulina genotypes with the northern ( Ensifer medicae ) or southern bacterium ( E. meliloti ) in a greenhouse experiment. Despite producing different numbers of root nodules (the structures in which the plants house the bacteria), neither northern nor southern plants produced more seeds, flowered earlier, or were more likely to flower when inoculated with their local rhizobia. We then used a pre-existing dataset to perform a genome scan for loci that showed elevated differentiation between field-collected plants that hosted different bacteria. None of the loci we identified belonged to the well-characterized suite of legume-rhizobia symbiosis genes, suggesting that the rhizobia do not drive genetic divergence between M. lupulina populations. Our results demonstrate that symbiont local adaptation has not evolved in this mutualism despite large-scale geographic variation in the identity of the interacting species.

  5. Symbiont interactions in a tripartite mutualism: exploring the presence and impact of antagonism between two fungus-growing ant mutualists.

    Directory of Open Access Journals (Sweden)

    Michael Poulsen

    Full Text Available Mutualistic associations are shaped by the interplay of cooperation and conflict among the partners involved, and it is becoming increasingly clear that within many mutualisms multiple partners simultaneously engage in beneficial interactions. Consequently, a more complete understanding of the dynamics within multipartite mutualism communities is essential for understanding the origin, specificity, and stability of mutualisms. Fungus-growing ants cultivate fungi for food and maintain antibiotic-producing Pseudonocardia actinobacteria on their cuticle that help defend the cultivar fungus from specialized parasites. Within both ant-fungus and ant-bacterium mutualisms, mixing of genetically distinct strains can lead to antagonistic interactions (i.e., competitive conflict, which may prevent the ants from rearing multiple strains of either of the mutualistic symbionts within individual colonies. The success of different ant-cultivar-bacterium combinations could ultimately be governed by antagonistic interactions between the two mutualists, either as inhibition of the cultivar by Pseudonocardia or vice versa. Here we explore cultivar-Pseudonocardia antagonism by evaluating in vitro interactions between strains of the two mutualists, and find frequent antagonistic interactions both from cultivars towards Pseudonocardia and vice versa. To test whether such in vitro antagonistic interactions affect ant colonies in vivo, we performed sub-colony experiments using species of Acromyrmex leaf-cutting ants. We created novel ant-fungus-bacterium pairings in which there was antagonism from one, both, or neither of the ants' microbial mutualists, and evaluated the effect of directional antagonism on cultivar biomass and Pseudonocardia abundance on the cuticle of workers within sub-colonies. Despite the presence of frequent in vitro growth suppression between cultivars and Pseudonocardia, antagonism from Pseudonocardia towards the cultivar did not reduce sub

  6. Plant-soil biota interactions and spatial distribution of black cherry in its native and invasive ranges

    NARCIS (Netherlands)

    Reinhart, K.O.; Packer, A.; Van der Putten, W.H.; Clay, K.A.

    2003-01-01

    One explanation for the higher abundance of invasive species in their non-native than native ranges is the escape from natural enemies. But there are few experimental studies comparing the parallel impact of enemies (or competitors and mutualists) on a plant species in its native and invaded ranges,

  7. 7 CFR 12.20 - NRCS responsibilities regarding highly erodible land.

    Science.gov (United States)

    2010-01-01

    ... WETLAND CONSERVATION Highly Erodible Land Conservation § 12.20 NRCS responsibilities regarding highly... public lists of highly erodible soil map units; (c) Make soil surveys for purposes of identifying highly erodible land; and (d) Provide technical guidance to conservation districts which approve conservation...

  8. Wind erodibility of soils from North Darfur State

    International Nuclear Information System (INIS)

    Medani, G. H.; Mustafa, M. A.

    2003-01-01

    Wind erodibility of soils (WE) is a prime factor for the prediction, assessment and mapping of wind erosion. Hence, this study was undertaken to generate WE data and pertinent relationships for North Darfur State. Surface soil samples (0-3 cm) were collected from forty farms scattered all over the state. Non-erodible soil particles (NEP) (>0.84 mm in diameter), WE and various relevant physical and chemical soil properties were determined. Regression analysis showed that NEP significantly (p 2 =0.825), clay (r 2 =0.754), silt (r 2 =0.737) and clay/ (silt + sand) ratio (r 2 =0.663), and decreased with increase in sand (r 2 =0.761), (silt+sand) / clay ratio (r 2 =0.766) and (silt+sand) / (clay+organic matter) ratio (r 2 =0.811). The four basic soil properties and their ratios gave the reverse effects on WE with slightly lower coefficients of determinations. Although organic matter is a slightly better predictor of both NEP and WE than (Si+S)/ (C+OM) ratio, the latter is preferred because it integrates in addition to OM resilient soil properties. A multiple regression equation with a relatively high coefficient of determination (R 2 =0.830) may also be used for predicting NEP from knowledge of the four prime soil properties. These properties accounted for only 62% of the variation of WE, thus it is not recommended for prediction purposes. The determined wind erodibility groups correlated very well with those established else where.(Author)

  9. Dynamic replacement and loss of soil carbon on eroding cropland

    Science.gov (United States)

    Harden, J.W.; Sharpe, J.M.; Parton, W.J.; Ojima, D.S.; Fries, T.L.; Huntington, T.G.; Dabney, S.M.

    1999-01-01

    Links between erosion/sedimentation history and soil carbon cycling were examined in a highly erosive setting in Mississippi loess soils. We sampled soils on (relatively) undisturbed and cropped hillslopes and measured C, N, 14C, and CO2 flux to characterize carbon storage and dynamics and to parameterize Century and spreadsheet 14C models for different erosion and tillage histories. For this site, where 100 years of intensive cotton cropping were followed by fertilization and contour plowing, there was an initial and dramatic decline in soil carbon content from 1870 to 1950, followed by a dramatic increase in soil carbon. Soil erosion amplifies C loss and recovery: About 100% of the original, prehistoric soil carbon was likely lost over 127 years of intensive land use, but about 30% of that carbon was replaced after 1950. The eroded cropland was therefore a local sink for CO2 since the 1950s. However, a net CO2 sink requires a full accounting of eroded carbon, which in turn requires that decomposition rates in lower slopes or wetlands be reduced to about 20% of the upland value. As a result, erosion may induce unaccounted sinks or sources of CO2, depending on the fate of eroded carbon and its protection from decomposition. For erosion rates typical of the United States, the sink terms may be large enough (1 Gt yr-1, back-of-the-envelope) to warrant a careful accounting of site management, cropping, and fertilization histories, as well as burial rates, for a more meaningful global assessment.

  10. A statistical model for horizontal mass flux of erodible soil

    International Nuclear Information System (INIS)

    Babiker, A.G.A.G.; Eltayeb, I.A.; Hassan, M.H.A.

    1986-11-01

    It is shown that the mass flux of erodible soil transported horizontally by a statistically distributed wind flow has a statistical distribution. Explicit expression for the probability density function, p.d.f., of the flux is derived for the case in which the wind speed has a Weibull distribution. The statistical distribution for a mass flux characterized by a generalized Bagnold formula is found to be Weibull for the case of zero threshold speed. Analytic and numerical values for the average horizontal mass flux of soil are obtained for various values of wind parameters, by evaluating the first moment of the flux density function. (author)

  11. Turing instability for a competitor-competitor-mutualist model with nonlinear cross-diffusion effects

    International Nuclear Information System (INIS)

    Wen, Zijuan; Fu, Shengmao

    2016-01-01

    This paper deals with a strongly coupled reaction-diffusion system modeling a competitor-competitor-mutualist three-species model with diffusion, self-diffusion and nonlinear cross-diffusion and subject to Neumann boundary conditions. First, we establish the persistence of a corresponding reaction-diffusion system without self- and cross-diffusion. Second, the global asymptotic stability of the unique positive equilibrium for weakly coupled PDE system is established by using a comparison method. Moreover, under certain conditions about the intra- and inter-species effects, we prove that the uniform positive steady state is linearly unstable for the cross-diffusion system when one of the cross-diffusions is large enough. The results indicate that Turing instability can be driven solely from strong diffusion effect of the first species (or the second species or the third species) due to the pressure of the second species (or the first species).

  12. The sixth mass coextinction: are most endangered species parasites and mutualists?

    Science.gov (United States)

    Dunn, Robert R; Harris, Nyeema C; Colwell, Robert K; Koh, Lian Pin; Sodhi, Navjot S

    2009-09-07

    The effects of species declines and extinction on biotic interactions remain poorly understood. The loss of a species is expected to result in the loss of other species that depend on it (coextinction), leading to cascading effects across trophic levels. Such effects are likely to be most severe in mutualistic and parasitic interactions. Indeed, models suggest that coextinction may be the most common form of biodiversity loss. Paradoxically, few historical or contemporary coextinction events have actually been recorded. We review the current knowledge of coextinction by: (i) considering plausible explanations for the discrepancy between predicted and observed coextinction rates; (ii) exploring the potential consequences of coextinctions; (iii) discussing the interactions and synergies between coextinction and other drivers of species loss, particularly climate change; and (iv) suggesting the way forward for understanding the phenomenon of coextinction, which may well be the most insidious threat to global biodiversity.

  13. Traps of carnivorous pitcher plants as a habitat: composition of the fluid, biodiversity and mutualistic activities.

    Science.gov (United States)

    Adlassnig, Wolfram; Peroutka, Marianne; Lendl, Thomas

    2011-02-01

    Carnivorous pitcher plants (CPPs) use cone-shaped leaves to trap animals for nutrient supply but are not able to kill all intruders of their traps. Numerous species, ranging from bacteria to vertrebrates, survive and propagate in the otherwise deadly traps. This paper reviews the literature on phytotelmata of CPPs. Fluid as a Habitat The volumes of pitchers range from 0·2 mL to 1·5 L. In Nepenthes and Cephalotus, the fluid is secreted by the trap; the other genera collect rain water. The fluid is usually acidic, rich in O(2) and contains digestive enzymes. In some taxa, toxins or detergents are found, or the fluid is extremely viscous. In Heliamphora or Sarracenia, the fluid differs little from pure water. Diversity Pitcher inquilines comprise bacteria, protozoa, algae, fungi, rotifers, crustaceans, arachnids, insects and amphibia. The dominant groups are protists and Dipteran larvae. The various species of CPPs host different sets of inquilines. Sarracenia purpurea hosts up to 165 species of inquilines, followed by Nepenthes ampullaria with 59 species, compared with only three species from Brocchinia reducta. Reasons for these differences include size, the life span of the pitcher as well as its fluid. MUTUALISTIC: Activities Inquilines closely interact with their host. Some live as parasites, but the vast majority are mutualists. Beneficial activities include secretion of enzymes, feeding on the plant's prey and successive excretion of inorganic nutrients, mechanical break up of the prey, removal of excessive prey and assimilation of atmospheric N(2). There is strong evidence that CPPs influence their phytotelm. Two strategies can be distinguished: (1) Nepenthes and Cephalotus produce acidic, toxic or digestive fluids and host a limited diversity of inquilines. (2) Genera without efficient enzymes such as Sarracenia or Heliamphora host diverse organisms and depend to a large extent on their symbionts for prey utilization.

  14. Beyond neutral and forbidden links: morphological matches and the assembly of mutualistic hawkmoth-plant networks.

    Science.gov (United States)

    Sazatornil, Federico D; Moré, Marcela; Benitez-Vieyra, Santiago; Cocucci, Andrea A; Kitching, Ian J; Schlumpberger, Boris O; Oliveira, Paulo E; Sazima, Marlies; Amorim, Felipe W

    2016-11-01

    A major challenge in evolutionary ecology is to understand how co-evolutionary processes shape patterns of interactions between species at community level. Pollination of flowers with long corolla tubes by long-tongued hawkmoths has been invoked as a showcase model of co-evolution. Recently, optimal foraging models have predicted that there might be a close association between mouthparts' length and the corolla depth of the visited flowers, thus favouring trait convergence and specialization at community level. Here, we assessed whether hawkmoths more frequently pollinate plants with floral tube lengths similar to their proboscis lengths (morphological match hypothesis) against abundance-based processes (neutral hypothesis) and ecological trait mismatches constraints (forbidden links hypothesis), and how these processes structure hawkmoth-plant mutualistic networks from five communities in four biogeographical regions of South America. We found convergence in morphological traits across the five communities and that the distribution of morphological differences between hawkmoths and plants is consistent with expectations under the morphological match hypothesis in three of the five communities. In the two remaining communities, which are ecotones between two distinct biogeographical areas, interactions are better predicted by the neutral hypothesis. Our findings are consistent with the idea that diffuse co-evolution drives the evolution of extremely long proboscises and flower tubes, and highlight the importance of morphological traits, beyond the forbidden links hypothesis, in structuring interactions between mutualistic partners, revealing that the role of niche-based processes can be much more complex than previously known. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.

  15. Informatics technology mimics ecology: dense, mutualistic collaboration networks are associated with higher publication rates.

    Directory of Open Access Journals (Sweden)

    Marco D Sorani

    Full Text Available Information technology (IT adoption enables biomedical research. Publications are an accepted measure of research output, and network models can describe the collaborative nature of publication. In particular, ecological networks can serve as analogies for publication and technology adoption. We constructed network models of adoption of bioinformatics programming languages and health IT (HIT from the literature.We selected seven programming languages and four types of HIT. We performed PubMed searches to identify publications since 2001. We calculated summary statistics and analyzed spatiotemporal relationships. Then, we assessed ecological models of specialization, cooperativity, competition, evolution, biodiversity, and stability associated with publications.Adoption of HIT has been variable, while scripting languages have experienced rapid adoption. Hospital systems had the largest HIT research corpus, while Perl had the largest language corpus. Scripting languages represented the largest connected network components. The relationship between edges and nodes was linear, though Bioconductor had more edges than expected and Perl had fewer. Spatiotemporal relationships were weak. Most languages shared a bioinformatics specialization and appeared mutualistic or competitive. HIT specializations varied. Specialization was highest for Bioconductor and radiology systems. Specialization and cooperativity were positively correlated among languages but negatively correlated among HIT. Rates of language evolution were similar. Biodiversity among languages grew in the first half of the decade and stabilized, while diversity among HIT was variable but flat. Compared with publications in 2001, correlation with publications one year later was positive while correlation after ten years was weak and negative.Adoption of new technologies can be unpredictable. Spatiotemporal relationships facilitate adoption but are not sufficient. As with ecosystems, dense

  16. Informatics technology mimics ecology: dense, mutualistic collaboration networks are associated with higher publication rates.

    Science.gov (United States)

    Sorani, Marco D

    2012-01-01

    Information technology (IT) adoption enables biomedical research. Publications are an accepted measure of research output, and network models can describe the collaborative nature of publication. In particular, ecological networks can serve as analogies for publication and technology adoption. We constructed network models of adoption of bioinformatics programming languages and health IT (HIT) from the literature.We selected seven programming languages and four types of HIT. We performed PubMed searches to identify publications since 2001. We calculated summary statistics and analyzed spatiotemporal relationships. Then, we assessed ecological models of specialization, cooperativity, competition, evolution, biodiversity, and stability associated with publications.Adoption of HIT has been variable, while scripting languages have experienced rapid adoption. Hospital systems had the largest HIT research corpus, while Perl had the largest language corpus. Scripting languages represented the largest connected network components. The relationship between edges and nodes was linear, though Bioconductor had more edges than expected and Perl had fewer. Spatiotemporal relationships were weak. Most languages shared a bioinformatics specialization and appeared mutualistic or competitive. HIT specializations varied. Specialization was highest for Bioconductor and radiology systems. Specialization and cooperativity were positively correlated among languages but negatively correlated among HIT. Rates of language evolution were similar. Biodiversity among languages grew in the first half of the decade and stabilized, while diversity among HIT was variable but flat. Compared with publications in 2001, correlation with publications one year later was positive while correlation after ten years was weak and negative.Adoption of new technologies can be unpredictable. Spatiotemporal relationships facilitate adoption but are not sufficient. As with ecosystems, dense, mutualistic

  17. Endophytic life strategies decoded by genome and transcriptome analyses of the mutualistic root symbiont Piriformospora indica.

    Directory of Open Access Journals (Sweden)

    Alga Zuccaro

    2011-10-01

    Full Text Available Recent sequencing projects have provided deep insight into fungal lifestyle-associated genomic adaptations. Here we report on the 25 Mb genome of the mutualistic root symbiont Piriformospora indica (Sebacinales, Basidiomycota and provide a global characterization of fungal transcriptional responses associated with the colonization of living and dead barley roots. Extensive comparative analysis of the P. indica genome with other Basidiomycota and Ascomycota fungi that have diverse lifestyle strategies identified features typically associated with both, biotrophism and saprotrophism. The tightly controlled expression of the lifestyle-associated gene sets during the onset of the symbiosis, revealed by microarray analysis, argues for a biphasic root colonization strategy of P. indica. This is supported by a cytological study that shows an early biotrophic growth followed by a cell death-associated phase. About 10% of the fungal genes induced during the biotrophic colonization encoded putative small secreted proteins (SSP, including several lectin-like proteins and members of a P. indica-specific gene family (DELD with a conserved novel seven-amino acids motif at the C-terminus. Similar to effectors found in other filamentous organisms, the occurrence of the DELDs correlated with the presence of transposable elements in gene-poor repeat-rich regions of the genome. This is the first in depth genomic study describing a mutualistic symbiont with a biphasic lifestyle. Our findings provide a significant advance in understanding development of biotrophic plant symbionts and suggest a series of incremental shifts along the continuum from saprotrophy towards biotrophy in the evolution of mycorrhizal association from decomposer fungi.

  18. Impact of land use change on soil erodibility

    Directory of Open Access Journals (Sweden)

    F. Taleshian Jeloudar

    2018-01-01

    Full Text Available Vulnerability of soil separates to detachment by water is described as soil erodibility by Universal Soil Loss Equation which can be affected by land use change. In this study it was attempted to quantify the changes of Universal Soil Loss Equation K-factor and its soil driving factors in three land uses including rangeland, rainfed farming, and orchards in Babolrood watershed, northern Iran. Soil composite samples were obtained from two layers in three land uses, and the related soil physico-chemical properties were measured. The rainfed farming land use showed the highest clay contents, but the highest amounts of soil organic matter and sand particles were found in orchard land use. The high intensity of tillage led to the significant decrease of soil aggregate stability and permeability in the rainfed farming land use. The Universal Soil Loss Equation K-factor was negatively correlated with soil permeability (r=-0.77**. In rangeland, the K-factor (0.045 Mg h/MJ/mm was significantly higher and the particle size distribution had a great impact on the K-factor. The orchard land use, converted from the rangeland, did not show any increase of soils erodibility and can potentially be introduced as a good alternative land use in sloping areas. However, more detailed studies on environmental, social and economic aspects of this land use are needed.

  19. Effects of organic and inorganic amendments on soil erodibility

    Directory of Open Access Journals (Sweden)

    Nutullah Özdemir

    2015-10-01

    Full Text Available The objective of the present investigation is to find out the effect of incorporating of various organic and inorganic matter sources such as lime (L, zeolit (Z, polyacrylamide (PAM and biosolid (BS on the instability index. A bulk surface (0–20 cm depth soil sample was taken from Samsun, in northern part of Turkey. Some soil properties were determined as follows; fine in texture, modarete in organic matter content, low in pH and free of alkaline problem. The soil samples were treated with the inorganic and organic materials at four different levels including the control treatments in a randomized factorial block design. The soil samples were incubated for ten weeks. After the incubation period, corn was grown in all pots. The results can be summarized as organic and inorganic matter treatments increased structure stability and decreased soil erodibility. Effectiveness of the treatments varied depending on the types and levels of organic and inorganic materials.

  20. How Welfare Regimes Generate and Erode Social Capital

    DEFF Research Database (Denmark)

    Larsen, Christian Albrekt

    2007-01-01

    in the USA and other liberal welfare regimes, while social capital is stable in the so-called social democratic and conservative welfare regimes. The second puzzle is why the group of social democratic regimes have extremely high levels of social trust. It is argued that both puzzles have to do......Comparative studies of social capital, operationalised as social trust between citizens, have revealed two major puzzles. The first puzzle has to do with the decline in social trust in the USA, which fuelled considerable debate about social capital. The question is why social capital erodes...... with the presence or absence of a poor and culturally distinct underclass. The social democratic welfare regimes hinder – while the liberal welfare regime generate – such underclass phenomena....

  1. Eroding market stability by proliferation of financial instruments

    Science.gov (United States)

    Caccioli, F.; Marsili, M.; Vivo, P.

    2009-10-01

    We contrast Arbitrage Pricing Theory (APT), the theoretical basis for the development of financial instruments, with a dynamical picture of an interacting market, in a simple setting. The proliferation of financial instruments apparently provides more means for risk diversification, making the market more efficient and complete. In the simple market of interacting traders discussed here, the proliferation of financial instruments erodes systemic stability and it drives the market to a critical state characterized by large susceptibility, strong fluctuations and enhanced correlations among risks. This suggests that the hypothesis of APT may not be compatible with a stable market dynamics. In this perspective, market stability acquires the properties of a common good, which suggests that appropriate measures should be introduced in derivative markets, to preserve stability. in here

  2. Analysis of eroded bovine teeth through laser speckle imaging

    Science.gov (United States)

    Koshoji, Nelson H.; Bussadori, Sandra K.; Bortoletto, Carolina C.; Oliveira, Marcelo T.; Prates, Renato A.; Deana, Alessandro M.

    2015-02-01

    Dental erosion is a non-carious lesion that causes progressive tooth wear of structure through chemical processes that do not involve bacterial action. Its origin is related to eating habits or systemic diseases involving tooth contact with substances that pose a very low pH. This work demonstrates a new methodology to quantify the erosion by coherent light scattering of tooth surface. This technique shows a correlation between acid etch duration and laser speckle contrast map (LASCA). The experimental groups presented a relative contrast between eroded and sound tissue of 17.8(45)%, 23.4 (68)% 39.2 (40)% and 44.3 (30)%, for 10 min, 20 min, 30 min and 40 min of acid etching, respectively.

  3. Recipient-Biased Competition for an Intracellularly Generated Cross-Fed Nutrient Is Required for Coexistence of Microbial Mutualists.

    Science.gov (United States)

    McCully, Alexandra L; LaSarre, Breah; McKinlay, James B

    2017-11-28

    Many mutualistic microbial relationships are based on nutrient cross-feeding. Traditionally, cross-feeding is viewed as being unidirectional, from the producer to the recipient. This is likely true when a producer's waste, such as a fermentation product, has value only for a recipient. However, in some cases the cross-fed nutrient holds value for both the producer and the recipient. In such cases, there is potential for nutrient reacquisition by producer cells in a population, leading to competition against recipients. Here, we investigated the consequences of interpartner competition for cross-fed nutrients on mutualism dynamics by using an anaerobic coculture pairing fermentative Escherichia coli and phototrophic Rhodopseudomonas palustris In this coculture, E. coli excretes waste organic acids that provide a carbon source for R. palustris In return, R. palustris cross-feeds E. coli ammonium (NH 4 + ), a compound that both species value. To explore the potential for interpartner competition, we first used a kinetic model to simulate cocultures with varied affinities for NH 4 + in each species. The model predicted that interpartner competition for NH 4 + could profoundly impact population dynamics. We then experimentally tested the predictions by culturing mutants lacking NH 4 + transporters in both NH 4 + competition assays and mutualistic cocultures. Both theoretical and experimental results indicated that the recipient must have a competitive advantage in acquiring cross-fed NH 4 + to sustain the mutualism. This recipient-biased competitive advantage is predicted to be crucial, particularly when the communally valuable nutrient is generated intracellularly. Thus, the very metabolites that form the basis for mutualistic cross-feeding can also be subject to competition between mutualistic partners. IMPORTANCE Mutualistic relationships, particularly those based on nutrient cross-feeding, promote stability of diverse ecosystems and drive global biogeochemical

  4. Plant Killing by Mutualistic Ants Increases the Density of Host Species Seedlings in the Dry Forest of Costa Rica

    OpenAIRE

    Amador-Vargas, Sabrina

    2012-01-01

    Some species of plant-mutualistic ants kill the vegetation growing in the vicinities of their host plant, creating an area of bare ground (clearing). The reduced competition in the clearing may facilitate the establishment of host species sprouts (clones and seedlings), which in turn benefits the ants with additional food and shelter (“sprout-establishment hypothesis”). To test this hypothesis, the density and origin of Acacia collinsii sprouts growing inside clearings and in the vicinities o...

  5. Compatible intracellular ion composition of the host improves carbon assimilation by zooxanthellae in mutualistic symbioses.

    Science.gov (United States)

    Seibt, C; Schlichter, D

    2001-09-01

    Cytosymbiotic algae within the host's plasma are exposed to completely different ionic conditions than microalgae living in the sea. The altered ionic gradients, in particular, could be the reason for higher in hospite carbon assimilation levels. To study the effect of varying extracellular ionic conditions on isolated zooxanthellae, their photosynthetic capacity in pure seawater was compared to that in a test medium in which the concentrations of the major inorganic ions, the pH and the osmolality were adjusted to the conditions measured in the host cytoplasm. In this test medium the ratio between oxygen evolution and carbon fixation was 1.2:1.0; in contrast, zooxanthellae in the hyperionic seawater medium showed a comparatively higher oxygen production (2.6:1.0). These results are attributed to a higher energy demand for ion regulation of the isolated algae in the hyperionic medium. Isolated cytosymbionts in seawater need more energy both for the readjustment to the original intracellular ion concentration within the host cell and also for the maintenance of a much steeper gradient during incubation under hyperionic conditions outside the host. The particular intracellular ion concentration of the host cells could have been a decisive evolutionary factor for the very successful establishment of the mutualistic symbioses between anthozoans and dinoflagellates more than 200 million years ago.

  6. Mutualistic interactions drive ecological niche convergence in a diverse butterfly community.

    Science.gov (United States)

    Elias, Marianne; Gompert, Zachariah; Jiggins, Chris; Willmott, Keith

    2008-12-02

    Ecological communities are structured in part by evolutionary interactions among their members. A number of recent studies incorporating phylogenetics into community ecology have upheld the paradigm that competition drives ecological divergence among species of the same guild. However, the role of other interspecific interactions, in particular positive interactions such as mutualism, remains poorly explored. We characterized the ecological niche and inferred phylogenetic relationships among members of a diverse community of neotropical Müllerian mimetic butterflies. Müllerian mimicry is one of the best studied examples of mutualism, in which unpalatable species converge in wing pattern locally to advertize their toxicity to predators. We provide evidence that mutualistic interactions can drive convergence along multiple ecological axes, outweighing both phylogeny and competition in shaping community structure. Our findings imply that ecological communities are adaptively assembled to a much greater degree than commonly suspected. In addition, our results show that phenotype and ecology are strongly linked and support the idea that mimicry can cause ecological speciation through multiple cascading effects on species' biology.

  7. Human Impacts and Climate Change Influence Nestedness and Modularity in Food-Web and Mutualistic Networks.

    Science.gov (United States)

    Takemoto, Kazuhiro; Kajihara, Kosuke

    2016-01-01

    Theoretical studies have indicated that nestedness and modularity-non-random structural patterns of ecological networks-influence the stability of ecosystems against perturbations; as such, climate change and human activity, as well as other sources of environmental perturbations, affect the nestedness and modularity of ecological networks. However, the effects of climate change and human activities on ecological networks are poorly understood. Here, we used a spatial analysis approach to examine the effects of climate change and human activities on the structural patterns of food webs and mutualistic networks, and found that ecological network structure is globally affected by climate change and human impacts, in addition to current climate. In pollination networks, for instance, nestedness increased and modularity decreased in response to increased human impacts. Modularity in seed-dispersal networks decreased with temperature change (i.e., warming), whereas food web nestedness increased and modularity declined in response to global warming. Although our findings are preliminary owing to data-analysis limitations, they enhance our understanding of the effects of environmental change on ecological communities.

  8. Human Impacts and Climate Change Influence Nestedness and Modularity in Food-Web and Mutualistic Networks.

    Directory of Open Access Journals (Sweden)

    Kazuhiro Takemoto

    Full Text Available Theoretical studies have indicated that nestedness and modularity-non-random structural patterns of ecological networks-influence the stability of ecosystems against perturbations; as such, climate change and human activity, as well as other sources of environmental perturbations, affect the nestedness and modularity of ecological networks. However, the effects of climate change and human activities on ecological networks are poorly understood. Here, we used a spatial analysis approach to examine the effects of climate change and human activities on the structural patterns of food webs and mutualistic networks, and found that ecological network structure is globally affected by climate change and human impacts, in addition to current climate. In pollination networks, for instance, nestedness increased and modularity decreased in response to increased human impacts. Modularity in seed-dispersal networks decreased with temperature change (i.e., warming, whereas food web nestedness increased and modularity declined in response to global warming. Although our findings are preliminary owing to data-analysis limitations, they enhance our understanding of the effects of environmental change on ecological communities.

  9. Evaluating multiple determinants of the structure of plant-animal mutualistic networks.

    Science.gov (United States)

    Vázquez, Diego P; Chacoff, Natacha P; Cagnolo, Luciano

    2009-08-01

    The structure of mutualistic networks is likely to result from the simultaneous influence of neutrality and the constraints imposed by complementarity in species phenotypes, phenologies, spatial distributions, phylogenetic relationships, and sampling artifacts. We develop a conceptual and methodological framework to evaluate the relative contributions of these potential determinants. Applying this approach to the analysis of a plant-pollinator network, we show that information on relative abundance and phenology suffices to predict several aggregate network properties (connectance, nestedness, interaction evenness, and interaction asymmetry). However, such information falls short of predicting the detailed network structure (the frequency of pairwise interactions), leaving a large amount of variation unexplained. Taken together, our results suggest that both relative species abundance and complementarity in spatiotemporal distribution contribute substantially to generate observed network patters, but that this information is by no means sufficient to predict the occurrence and frequency of pairwise interactions. Future studies could use our methodological framework to evaluate the generality of our findings in a representative sample of study systems with contrasting ecological conditions.

  10. A mutualistic approach to morality: the evolution of fairness by partner choice.

    Science.gov (United States)

    Baumard, Nicolas; André, Jean-Baptiste; Sperber, Dan

    2013-02-01

    What makes humans moral beings? This question can be understood either as a proximate “how” question or as an ultimate “why” question. The “how” question is about the mental and social mechanisms that produce moral judgments and interactions, and has been investigated by psychologists and social scientists. The “why” question is about the fitness consequences that explain why humans have morality, and has been discussed by evolutionary biologists in the context of the evolution of cooperation. Our goal here is to contribute to a fruitful articulation of such proximate and ultimate explanations of human morality. We develop an approach to morality as an adaptation to an environment in which individuals were in competition to be chosen and recruited in mutually advantageous cooperative interactions. In this environment, the best strategy is to treat others with impartiality and to share the costs and benefits of cooperation equally. Those who offer less than others will be left out of cooperation; conversely, those who offer more will be exploited by their partners. In line with this mutualistic approach, the study of a range of economic games involving property rights, collective actions, mutual help and punishment shows that participants’ distributions aim at sharing the costs and benefits of interactions in an impartial way. In particular, the distribution of resources is influenced by effort and talent, and the perception of each participant’s rights on the resources to be distributed.

  11. Mutualistic interactions drive ecological niche convergence in a diverse butterfly community.

    Directory of Open Access Journals (Sweden)

    Marianne Elias

    2008-12-01

    Full Text Available Ecological communities are structured in part by evolutionary interactions among their members. A number of recent studies incorporating phylogenetics into community ecology have upheld the paradigm that competition drives ecological divergence among species of the same guild. However, the role of other interspecific interactions, in particular positive interactions such as mutualism, remains poorly explored. We characterized the ecological niche and inferred phylogenetic relationships among members of a diverse community of neotropical Müllerian mimetic butterflies. Müllerian mimicry is one of the best studied examples of mutualism, in which unpalatable species converge in wing pattern locally to advertize their toxicity to predators. We provide evidence that mutualistic interactions can drive convergence along multiple ecological axes, outweighing both phylogeny and competition in shaping community structure. Our findings imply that ecological communities are adaptively assembled to a much greater degree than commonly suspected. In addition, our results show that phenotype and ecology are strongly linked and support the idea that mimicry can cause ecological speciation through multiple cascading effects on species' biology.

  12. Chemical camouflage: a key process in shaping an ant-treehopper and fig-fig wasp mutualistic network.

    Science.gov (United States)

    Wang, Bo; Lu, Min; Cook, James M; Yang, Da-Rong; Dunn, Derek W; Wang, Rui-Wu

    2018-01-30

    Different types of mutualisms may interact, co-evolve and form complex networks of interdependences, but how species interact in networks of a mutualistic community and maintain its stability remains unclear. In a mutualistic network between treehoppers-weaver ants and fig-pollinating wasps, we found that the cuticular hydrocarbons of the treehoppers are more similar to the surface chemical profiles of fig inflorescence branches (FIB) than the cuticular hydrocarbons of the fig wasps. Behavioral assays showed that the cuticular hydrocarbons from both treehoppers and FIBs reduce the propensity of weaver ants to attack treehoppers even in the absence of honeydew rewards, suggesting that chemical camouflage helps enforce the mutualism between weaver ants and treehoppers. High levels of weaver ant and treehopper abundances help maintain the dominance of pollinating fig wasps in the fig wasp community and also increase fig seed production, as a result of discriminative predation and disturbance by weaver ants of ovipositing non-pollinating fig wasps (NPFWs). Ants therefore help preserve this fig-pollinating wasp mutualism from over exploitation by NPFWs. Our results imply that in this mutualistic network chemical camouflage plays a decisive role in regulating the behavior of a key species and indirectly shaping the architecture of complex arthropod-plant interactions.

  13. The effect of consumers and mutualists of Vaccinium membranaceum at Mount St. Helens: dependence on successional context.

    Directory of Open Access Journals (Sweden)

    Suann Yang

    Full Text Available In contrast to secondary succession, studies of terrestrial primary succession largely ignore the role of biotic interactions, other than plant facilitation and competition, despite the expectation that simplified interaction webs and propagule-dependent demographics may amplify the effects of consumers and mutualists. We investigated whether successional context determined the impact of consumers and mutualists by quantifying their effects on reproduction by the shrub Vaccinium membranaceum in primary and secondary successional sites at Mount St. Helens (Washington, USA, and used simulations to explore the effects of these interactions on colonization. Species interactions differed substantially between sites, and the combined effect of consumers and mutualists was much more strongly negative for primary successional plants. Because greater local control of propagule pressure is expected to increase successional rates, we evaluated the role of dispersal in the context of these interactions. Our simulations showed that even a small local seed source greatly increases population growth rates, thereby balancing strong consumer pressure. The prevalence of strong negative interactions in the primary successional site is a reminder that successional communities will not exhibit the distribution of interaction strengths characteristic of stable communities, and suggests the potential utility of modeling succession as the consequence of interaction strengths.

  14. The abrasive effect of commercial whitening toothpastes on eroded enamel.

    Science.gov (United States)

    Mosquim, Victor; Martines Souza, Beatriz; Foratori Junior, Gerson Aparecido; Wang, Linda; Magalhães, Ana Carolina

    2017-06-01

    To evaluate the in vitro abrasive effect of commercial whitening toothpastes on eroded bovine enamel samples in respect to erosive tooth wear. 72 bovine crowns were embedded, polished and subjected to the baseline profile analysis. The samples were then protected in 2/3 of the enamel surface and were randomly assigned to six groups (n= 12/group): G1: Oral-B 3D White, G2: Close-up Diamond Attraction Power White, G3: Sorriso Xtreme White 4D, G4: Colgate Luminous White, G5: Crest (conventional toothpaste), G6:erosion only (control). All samples were submitted to an erosive pH cycling (4 x 90 seconds in 0.1% citric acid, pH 2.5, per day) and abrasive challenges (2 x 15 seconds, per day) for 7 days. After the first and the last daily cycles, the samples were subjected to abrasive challenges, using a toothbrushing machine, soft toothbrushes and slurry of the tested toothpastes (1.5 N). Between the challenges, the samples were immersed in artificial saliva. The final profile was obtained and overlaid to the baseline profile for the calculation of the erosive tooth wear (μm). The data were subjected to Kruskal-Wallis/Dunn tests (Penamel wear (3.68±1.06 μm), similarly to G3 (3.17± 0.80 μm) and G4 (3.44± 1.29 μm). G3 and G4 performed similarly between them and compared with G5 (2.35± 1.44 μm). G2 (1.51± 0.95 μm) and G6 (0.85± 0.36 μm) showed the lowest enamel wear, which did not differ between them and from G5. Oral-B 3D White showed the highest abrasive potential while Close-up Diamond Attraction Power White showed the lowest abrasive potential on eroded enamel in vitro. This study showed that some commercial whitening toothpastes, especially those containing pyrophosphate associated with hydrated silica, enhanced enamel erosive wear.

  15. Differential effects of biochar on soils within an eroded field

    Science.gov (United States)

    Schumacher, Thomas; Chintala, Rajesh; Sandhu, Saroop; Kumar, Sandeep; Clay, Dave; Gelderman, Ron; Papiernik, Sharon; Malo, Douglas; Clay, Sharon; Julson, Jim

    2015-04-01

    Future uses of biochar will in part be dependent not only on the effects of biochar on soil processes but also on the availability and economics of biochar production. If pyrolysis for production of bio-oil and syngas becomes wide-spread, biochar as a by-product of bio-oil production will be widely available and relatively inexpensive compared to the production of biochar as primary product. Biochar produced as a by-product of optimized bio-oil production using regionally available feedstocks was examined for properties and for use as an amendment targeted to contrasting soils within an eroded field in an on-farm study initiated in 2013 at Brookings, South Dakota, USA. Three plant based biochar materials produced from carbon optimized gasification of corn stover (Zea mays L.), Ponderosa pine (Pinus ponderosa Lawson and C. Lawson) wood residue, and switchgrass (Panicum virgatum L.) were applied at a 1% (w/w) rate to a Maddock soil (Sandy, Mixed, Frigid Entic Hapludolls) located in an eroded upper landscape position and a Brookings soil (Fine-Silty, Mixed, Superactive, Frigid Pachic Hapludolls) located in a depositional landscape position. The cropping system within this agricultural landscape was a corn (Zea mays L.) and soybean (Glycine max L.) rotation. Biochar physical and chemical properties for each of the feedstocks were determined including pH, surface area, surface charge potential, C-distribution, ash content, macro and micro nutrient composition. Yields, nutrient content, and carbon isotope ratio measurements were made on the harvested seed. Soil physical properties measured included water retention, bulk density, and water infiltration from a ponded double ring infiltrometer. Laboratory studies were conducted to determine the effects of biochar on partitioning of nitrate and phosphorus at soil surface exchange complex and the extracellular enzymes activity of C and N cycles. Crop yields were increased only in the Maddock soil. Biochar interacted with each

  16. Positive feedback between mycorrhizal fungi and plants influences plant invasion success and resistance to invasion.

    Science.gov (United States)

    Zhang, Qian; Yang, Ruyi; Tang, Jianjun; Yang, Haishui; Hu, Shuijin; Chen, Xin

    2010-08-24

    Negative or positive feedback between arbuscular mycorrhizal fungi (AMF) and host plants can contribute to plant species interactions, but how this feedback affects plant invasion or resistance to invasion is not well known. Here we tested how alterations in AMF community induced by an invasive plant species generate feedback to the invasive plant itself and affect subsequent interactions between the invasive species and its native neighbors. We first examined the effects of the invasive forb Solidago canadensis L. on AMF communities comprising five different AMF species. We then examined the effects of the altered AMF community on mutualisms formed with the native legume forb species Kummerowia striata (Thunb.) Schindl. and on the interaction between the invasive and native plants. The host preferences of the five AMF were also assessed to test whether the AMF form preferred mutualistic relations with the invasive and/or the native species. We found that S. canadensis altered AMF spore composition by increasing one AMF species (Glomus geosporum) while reducing Glomus mosseae, which is the dominant species in the field. The host preference test showed that S. canadensis had promoted the abundance of AMF species (G. geosporum) that most promoted its own growth. As a consequence, the altered AMF community enhanced the competitiveness of invasive S. canadensis at the expense of K. striata. Our results demonstrate that the invasive S. canadensis alters soil AMF community composition because of fungal-host preference. This change in the composition of the AMF community generates positive feedback to the invasive S. canadensis itself and decreases AM associations with native K. striata, thereby making the native K. striata less dominant.

  17. Positive feedback between mycorrhizal fungi and plants influences plant invasion success and resistance to invasion.

    Directory of Open Access Journals (Sweden)

    Qian Zhang

    2010-08-01

    Full Text Available Negative or positive feedback between arbuscular mycorrhizal fungi (AMF and host plants can contribute to plant species interactions, but how this feedback affects plant invasion or resistance to invasion is not well known. Here we tested how alterations in AMF community induced by an invasive plant species generate feedback to the invasive plant itself and affect subsequent interactions between the invasive species and its native neighbors. We first examined the effects of the invasive forb Solidago canadensis L. on AMF communities comprising five different AMF species. We then examined the effects of the altered AMF community on mutualisms formed with the native legume forb species Kummerowia striata (Thunb. Schindl. and on the interaction between the invasive and native plants. The host preferences of the five AMF were also assessed to test whether the AMF form preferred mutualistic relations with the invasive and/or the native species. We found that S. canadensis altered AMF spore composition by increasing one AMF species (Glomus geosporum while reducing Glomus mosseae, which is the dominant species in the field. The host preference test showed that S. canadensis had promoted the abundance of AMF species (G. geosporum that most promoted its own growth. As a consequence, the altered AMF community enhanced the competitiveness of invasive S. canadensis at the expense of K. striata. Our results demonstrate that the invasive S. canadensis alters soil AMF community composition because of fungal-host preference. This change in the composition of the AMF community generates positive feedback to the invasive S. canadensis itself and decreases AM associations with native K. striata, thereby making the native K. striata less dominant.

  18. Towards prediction of soil erodibility using hyperspectral information: a case study in a semi-arid region of Iran

    DEFF Research Database (Denmark)

    Ostovari, Yaser; Ghorbani-Dashtaki, Shoja; Bahrami, Hossein-Ali

    2018-01-01

    and develop Spectrotransfer Function (STF) using spectral reflectance information and Pedotransfer Function (PTF) to predict the K-factor, respectively. The derived STF was compared with developed PTF using measurable soil properties by Ostovari et al. (2016) and the Universal Soil Loss Equation (USLE......Soil Visible–Near-Infrared (Vis-NIR) spectroscopy has become an applicable and interesting technique to evaluate a number of soil properties because it is a fast, cost-effective, and non-invasive measurement technique. The main objective of the study to predict soil erodibility (K-factor), soil...... organic matter (SOM), and calcium carbonate equivalent (CaCO3) in calcareous soils of semi-arid regions located in south of Iran using spectral reflectance information in the Vis-NIR range. The K-factor was measured in 40 erosion plots under natural rainfall and the spectral reflectance of soil samples...

  19. Ranking of critical species to preserve the functionality of mutualistic networks using the k-core decomposition.

    Science.gov (United States)

    García-Algarra, Javier; Pastor, Juan Manuel; Iriondo, José María; Galeano, Javier

    2017-01-01

    Network analysis has become a relevant approach to analyze cascading species extinctions resulting from perturbations on mutualistic interactions as a result of environmental change. In this context, it is essential to be able to point out key species, whose stability would prevent cascading extinctions, and the consequent loss of ecosystem function. In this study, we aim to explain how the k -core decomposition sheds light on the understanding the robustness of bipartite mutualistic networks. We defined three k -magnitudes based on the k -core decomposition: k -radius, k -degree, and k -risk. The first one, k -radius, quantifies the distance from a node to the innermost shell of the partner guild, while k -degree provides a measure of centrality in the k -shell based decomposition. k -risk is a way to measure the vulnerability of a network to the loss of a particular species. Using these magnitudes we analyzed 89 mutualistic networks involving plant pollinators or seed dispersers. Two static extinction procedures were implemented in which k -degree and k -risk were compared against other commonly used ranking indexes, as for example MusRank, explained in detail in Material and Methods. When extinctions take place in both guilds, k -risk is the best ranking index if the goal is to identify the key species to preserve the giant component. When species are removed only in the primary class and cascading extinctions are measured in the secondary class, the most effective ranking index to identify the key species to preserve the giant component is k -degree. However, MusRank index was more effective when the goal is to identify the key species to preserve the greatest species richness in the second class. The k -core decomposition offers a new topological view of the structure of mutualistic networks. The new k -radius, k -degree and k -risk magnitudes take advantage of its properties and provide new insight into the structure of mutualistic networks. The k -risk and k

  20. Ranking of critical species to preserve the functionality of mutualistic networks using the k-core decomposition

    Directory of Open Access Journals (Sweden)

    Javier García-Algarra

    2017-05-01

    Full Text Available Background Network analysis has become a relevant approach to analyze cascading species extinctions resulting from perturbations on mutualistic interactions as a result of environmental change. In this context, it is essential to be able to point out key species, whose stability would prevent cascading extinctions, and the consequent loss of ecosystem function. In this study, we aim to explain how the k-core decomposition sheds light on the understanding the robustness of bipartite mutualistic networks. Methods We defined three k-magnitudes based on the k-core decomposition: k-radius, k-degree, and k-risk. The first one, k-radius, quantifies the distance from a node to the innermost shell of the partner guild, while k-degree provides a measure of centrality in the k-shell based decomposition. k-risk is a way to measure the vulnerability of a network to the loss of a particular species. Using these magnitudes we analyzed 89 mutualistic networks involving plant pollinators or seed dispersers. Two static extinction procedures were implemented in which k-degree and k-risk were compared against other commonly used ranking indexes, as for example MusRank, explained in detail in Material and Methods. Results When extinctions take place in both guilds, k-risk is the best ranking index if the goal is to identify the key species to preserve the giant component. When species are removed only in the primary class and cascading extinctions are measured in the secondary class, the most effective ranking index to identify the key species to preserve the giant component is k-degree. However, MusRank index was more effective when the goal is to identify the key species to preserve the greatest species richness in the second class. Discussion The k-core decomposition offers a new topological view of the structure of mutualistic networks. The new k-radius, k-degree and k-risk magnitudes take advantage of its properties and provide new insight into the structure of

  1. EROD induction by environmental contaminants in avian embryo livers

    Energy Technology Data Exchange (ETDEWEB)

    Brunstroem, B.; Halldin, K. [Department of Environmental Toxicology, Uppsala University, Norbyvaegen 18A SE-752 36, Uppsala (Sweden)

    1998-11-01

    The CYP1A (EROD)-inducing potencies of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 3,3minutes or feet,4,4minutes or feet,5-pentachlorobiphenyl (PCB126) and benzo(k)fluoranthene (B(k)F) were studied in avian embryo livers. TCDD and PCB126 proved to be much more potent as inducers in the chicken than in the other species examined. This finding is consistent with a considerably higher sensitivity of the chicken compared with a number of other avian species to the embryotoxic effects of these compounds. Furthermore, the relative potencies of the tested Ah receptor agonists as CYP1A inducers differed substantially between species. B(k)F and PCB126 showed similar induction potencies in domestic duck embryos, whereas PCB126 is much more potent than B(k)F in the chicken. Also, the potency of PCB126,relative to that of TCDD, was much lower in quail embryo liver in vitro than in chicken embryo liver. Thus, there are large interspecific differences in birds in the sensitivity to CYP1A inducers and furthermore, the relative potencies of these compounds may differ substantially between species. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  2. EROD induction by environmental contaminants in avian embryo livers

    International Nuclear Information System (INIS)

    Brunstroem, B.; Halldin, K.

    1998-01-01

    The CYP1A (EROD)-inducing potencies of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 3,3minutes or feet,4,4minutes or feet,5-pentachlorobiphenyl (PCB126) and benzo(k)fluoranthene (B(k)F) were studied in avian embryo livers. TCDD and PCB126 proved to be much more potent as inducers in the chicken than in the other species examined. This finding is consistent with a considerably higher sensitivity of the chicken compared with a number of other avian species to the embryotoxic effects of these compounds. Furthermore, the relative potencies of the tested Ah receptor agonists as CYP1A inducers differed substantially between species. B(k)F and PCB126 showed similar induction potencies in domestic duck embryos, whereas PCB126 is much more potent than B(k)F in the chicken. Also, the potency of PCB126, relative to that of TCDD, was much lower in quail embryo liver in vitro than in chicken embryo liver. Thus, there are large interspecific differences in birds in the sensitivity to CYP1A inducers and furthermore, the relative potencies of these compounds may differ substantially between species. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  3. Eroding students' rural motivation: first do no harm?

    Science.gov (United States)

    Hurst, Samia

    2014-01-01

    Migration of health professionals is one of the drivers of vast inequalities in access to healthcare, as medical graduates tend to move away from both poorer countries and rural areas. One of the central ethical problems raised in attempting to alleviate these inequalities is the tension between the healthcare needs of under-served patients and the rights of medical graduates to choose their place of work and specialty. If medical graduates had greater motivation to work in under-served rural areas, this tension would decrease accordingly. Medical schools have a duty to avoid eroding existing motivation for such training and practice. This duty has practical implications. Medical students' motivation regarding their choice of specialty changes during medical training, turning them away from choices such as primary care and rural practice towards more highly specialised, more hospital based specialties. Although students may be victims of a number of biases in the initial assessment, this is unlikely to be the whole story. Students' priorities are likely to change based on their admiration for specialist role models and the visibility of the financial and non-financial rewards attached to these specialties. Students may also have a false expectation upon admission that they will be proficient in rural medicine on graduation, and change their mind once they realise the limits of their skills in that area. Although the measures required to reverse this effect currently lack a solid evidence base, they are plausible and supported by the available data.

  4. Cranium eroding sweat gland carcinoma. A case report

    International Nuclear Information System (INIS)

    Arslan, M.; Karadeniz, A. N.; Aksu, G.; Guveli, M.

    2005-01-01

    Background. Sweat gland carcinomas are rare tumors. Eccrine sweat gland carcinomas are also very rare, with only about 200 cases reported in the world literature and only one of them was eroding the cranium. Treatment modalities of these carcinomas are not well known. Case report. Our patient was 47 years old female. Since 1989, she was operated on six times because of the tumour relapses. After each operation, the pathological results were: sweat gland adenoma, sweat gland tumour, cylindroma, turban tumour, malign cylindiroma. That was her seventh relapse. On examination, a lesion of the size 10 x 6 cm was observed in the left parietal region. Computed tomography showed the lesion had the size of 11 x 5 cm, and was destroying the tabula externa, diploic region and tabula. The tumour was invading the dura and causing periost reaction. Surgery and postoperative radiotherapy treatment was planned because of malign transformation and risk of recurrence. Conclusions. Only one case with cranium erosion was reported in literature. In our case, also intracranial extension of the tumor was observed. (author)

  5. Correlation of erosion and erodibility assessments using caesium-137

    International Nuclear Information System (INIS)

    Elliott, G.L.; Campbell, B.L.; Loughran, R.J.

    1984-01-01

    Data are presented which show that in soils in which net erosion is occurring, the content of the environmental isotope caesium-137 is highly correlated with soil loss. Other soil characteristics which may be related to the caesium content and therefore to soil loss have also been examined. Of these factors, an improved index of soil aggregate stability explained the most variation in caesium content (52%). Soil organic matter content explained 27% of variation in caesium content and other soil erodibility indices based on quantitative measurement of aggregate stability, explained between 6% and 21% of the variation. Indices based on implied hydrologic characteristics, implied aggregation and clay dispersion explained between 1% and 3% of caesium variation. It is suggested that practical factors of soil protection are relevant to the prediction of erosion hazard and may be more relevant than some indices of soil resistance. It is noted further that caesium-137 content of a soil gives every indication of being a most suitable predictor of soil erosion status

  6. Value-Eroding Teacher Behaviors Scale: A Validity and Reliability Study

    Science.gov (United States)

    Arseven, Zeynep; Kiliç, Abdurrahman; Sahin, Seyma

    2016-01-01

    In the present study, it is aimed to develop a valid and reliable scale for determining value-eroding behaviors of teachers, hence their values of judgment. The items of the "Value-eroding Teacher Behaviors Scale" were designed in the form of 5-point likert type rating scale. The exploratory factor analysis (EFA) was conducted to…

  7. 75 FR 75961 - Notice of Implementation of the Wind Erosion Prediction System for Soil Erodibility System...

    Science.gov (United States)

    2010-12-07

    ... implementation of the WEPS system does not affect the Highly Erodible Map Unit List contained in the NRCS Field Office Technical Guide as of January 1, 1990. This 1990 list will continue to be used for all erodibility... plant damage, and predict PM-10 emissions when wind speeds exceed the erosion threshold. The WEPS model...

  8. Soil erodibility mapping using three approaches in the Tangiers province –Northern Morocco

    Directory of Open Access Journals (Sweden)

    Hamza Iaaich

    2016-09-01

    Full Text Available Soil erodibility is a key factor in assessing soil loss rates. In fact, soil loss is the most occurring land degradation form in Morocco, affecting rural and urban vulnerable areas. This work deals with large scale mapping of soil erodibility using three mapping approaches: (i the CORINE approach developed for Europe by the JRC; (ii the UNEP/FAO approach developed within the frame of the United Nations Environmental Program for the Mediterranean area; (iii the Universal Soil Loss Equation (USLE K factor. Our study zone is the province of Tangiers, North-West of Morocco. For each approach, we mapped and analyzed different erodibility factors in terms of parent material, topography and soil attributes. The thematic maps were then integrated using a Geographic Information System to elaborate a soil erodibility map for each of the three approaches. Finally, the validity of each approach was checked in the field, focusing on highly eroded areas, by confronting the estimated soil erodibility and the erosion state as observed in the field. We used three statistical indicators for validation: overall accuracy, weighted Kappa factor and omission/commission errors. We found that the UNEP/FAO approach, based principally on lithofacies and topography as mapping inputs, is the most adapted for the case of our study zone, followed by the CORINE approach. The USLE K factor underestimated the soil erodibility, especially for highly eroded areas.

  9. 7 CFR 12.21 - Identification of highly erodible lands criteria.

    Science.gov (United States)

    2010-01-01

    ... the Universal Soil Loss Equation (USLE): (i) Rainfall and runoff (R); (ii) The degree to which the... and surface soil moisture (C) and the degree to which soil resists wind erosion (I). (3) The USLE is...) Basis for identification as highly erodible. Soil map units and an erodibility index will be used as the...

  10. Knocking out knotweed: research pins down a rogue invasive

    Science.gov (United States)

    Natasha Vizcarra; Shannon Claeson

    2015-01-01

    Bohemian knotweed spreads aggressively along rivers. This invasive weed chokes waterways, displaces native plants, erodes riverbanks, and keeps tree seedlings from growing. Communities in the Pacific Northwest spend millions of dollars to eradicate it on the assumption that it harms fish habitats.But knotweed is difficult to kill. It takes...

  11. A management guide for invasive plants in southern forests

    Science.gov (United States)

    James H. Miller; Steven T. Manning; Stephen F. Enloe

    2013-01-01

    Invasions of nonnative plants into forests of the Southern United States continue to spread and include new species, increasingly eroding forest productivity, hindering forest use and management activities, and degrading diversity and wildlife habitat. This book provides the latest information on how to organize and enact prevention programs, build strategies,...

  12. Mutualistic Symbiosis between Researchers and Educators: the Case of Two Education Officers on the Joides Resolution

    Science.gov (United States)

    Cicconi, Alessia; Burgio, Marion; Cooper, Sharon

    2017-04-01

    Geoscience education from the primary school through the high school level is highly effected by the way teachers themselves deal with the teaching of science. Many studies on science education in general have found that teachers who lack research experience are less confident in teaching science with an inquiry methodology - the way that reflects how science really works and is found the most effective regarding students' achievement in science and their confidence in addressing STEM careers. The International Ocean Discovery Program (IODP) has carried out for years an education and outreach program that involves educators and teachers, with the position of Education Officer, in the expeditions on board the JOIDES Resolution (JR), an oceanographic vessel specialized in drilling ocean sediment cores for research purposes. This immersive experience gives teachers the opportunity to be part of the research process with the aim, among many others, to fill the gap that sometimes exists between how science is explained in textbooks and the real practice of scientific research. Using a scientific parallel, having teachers working with researchers could be considered a mutualistic symbiosis: on one hand researchers have a job, usually difficult to understand for the public and made simple by the teacher; on the other hand the teacher, working with researchers as a researcher will gain more confidence using an inquiry methodology in teaching science. In this oral presentation we want to present the outcomes of the outreach projects of two Education Officers, the first one who participated in Expedition 360 and the second one that will take part in the Expedition 367, in terms of 1) their perception and opinion of this immersive experience seen as professional development; 2) perceptions and opinions of teachers involved from shore, with or without their classes. This exploratory study has carried out with qualitative and quantitative methodology using questionnaires and

  13. Invasive Candidiasis

    Science.gov (United States)

    ... Waterborne, and Environmental Diseases Mycotic Diseases Branch Invasive Candidiasis Recommend on Facebook Tweet Share Compartir Global Emergence ... antifungal drugs. Learn more about C. auris Invasive candidiasis is an infection caused by a yeast (a ...

  14. Relationship between soil erodibility and modeled infiltration rate in different soils

    Science.gov (United States)

    Wang, Guoqiang; Fang, Qingqing; Wu, Binbin; Yang, Huicai; Xu, Zongxue

    2015-09-01

    The relationship between soil erodibility, which is hard to measure, and modeled infiltration rate were rarely researched. Here, the soil erodibility factors (K and Ke in the USLE, Ki and K1 in the WEPP) were calculated and the infiltration rates were modeled based on the designed laboratory simulation experiments and proposed infiltration model, in order to build their relationship. The impacts of compost amendment on the soil erosion characteristics and relationship were also studied. Two contrasting agricultural soils (bare and cultivated fluvo-aquic soils) were used, and different poultry compost contents (control, low and high) were applied to both soils. The results indicated that the runoff rate, sediment yield rate and soil erodibility of the bare soil treatments were generally higher than those of the corresponding cultivated soil treatments. The application of composts generally decreased sediment yield and soil erodibility but did not always decrease runoff. The comparison of measured and modeled infiltration rates indicated that the model represented the infiltration processes well with an N-S coefficient of 0.84 for overall treatments. Significant negative logarithmic correlations have been found between final infiltration rate (FIR) and the four soil erodibility factors, and the relationship between USLE-K and FIR demonstrated the best correlation. The application of poultry composts would not influence the logarithmic relationship between FIR and soil erodibility. Our study provided a useful tool to estimate soil erodibility.

  15. Invasive plant suppresses the growth of native tree seedlings by disrupting belowground mutualisms.

    Directory of Open Access Journals (Sweden)

    Kristina A Stinson

    2006-05-01

    Full Text Available The impact of exotic species on native organisms is widely acknowledged, but poorly understood. Very few studies have empirically investigated how invading plants may alter delicate ecological interactions among resident species in the invaded range. We present novel evidence that antifungal phytochemistry of the invasive plant, Alliaria petiolata, a European invader of North American forests, suppresses native plant growth by disrupting mutualistic associations between native canopy tree seedlings and belowground arbuscular mycorrhizal fungi. Our results elucidate an indirect mechanism by which invasive plants can impact native flora, and may help explain how this plant successfully invades relatively undisturbed forest habitat.

  16. [Spatiotemporal variation of typical red soil eroded landscape pattern: a case study in Changting County of Fujian Province].

    Science.gov (United States)

    Wu, Guo-sheng; Lin, Hui-hua; Zhu, He-jian; Sha, Jin-ming; Dai, Wen-yuan

    2011-07-01

    Based on the 1988, 2000, and 2007 remote sensing images of a typical red soil eroded region (Changting County, Fujian Province) and the digital elevation model (DEM), the eroded landscape types were worked out, and the changes of the eroded landscape pattern in the region from 1988 to 2007 were analyzed with the spatial mathematics model. In 1988-2007, different eroded landscape types in the region had the characteristics of inter-transfer, mainly manifested in the transfer from seriously eroded to lightly eroded types but still existed small amount of the transference from lightly eroded to seriously eroded types. Little change was observed in the controid of the eroded landscape. In the County, Hetian Town was all along the eroded center. During the study period, the landscape pattern index showed a tendency of low heterogeneity, low fragmentation, and high regularization at landscape level, but an overall improvement and expansion of lightly eroded and easy-to-tackle patches as well as the partial improvement and fragmentation of seriously eroded and difficult-to-tackle patches at patch level.

  17. Harlequin duck capture and EROD activity data from Prince William Sound, Alaska, 2011, 2013, 2014

    Data.gov (United States)

    Department of the Interior — This data set includes capture information and ethoxyresorufin­O­deethylase (EROD) activity results for harlequin ducks sampled during March 2011, 2013, and 2014 in...

  18. Elastic wave generated by granular impact on rough and erodible surfaces

    Science.gov (United States)

    Bachelet, Vincent; Mangeney, Anne; de Rosny, Julien; Toussaint, Renaud; Farin, Maxime

    2018-01-01

    The elastic waves generated by impactors hitting rough and erodible surfaces are studied. For this purpose, beads of variable materials, diameters, and velocities are dropped on (i) a smooth PMMA plate, (ii) stuck glass beads on the PMMA plate to create roughness, and (iii) the rough plate covered with layers of free particles to investigate erodible beds. The Hertz model validity to describe impacts on a smooth surface is confirmed. For rough and erodible surfaces, an empirical scaling law that relates the elastic energy to the radius Rb and normal velocity Vz of the impactor is deduced from experimental data. In addition, the radiated elastic energy is found to decrease exponentially with respect to the bed thickness. Lastly, we show that the variability of the elastic energy among shocks increases from some percents to 70% between smooth and erodible surfaces. This work is a first step to better quantify seismic emissions of rock impacts in natural environment, in particular on unconsolidated soils.

  19. Wind-Eroded Silicate as a Source of Hydrogen Peroxide on Mars

    Science.gov (United States)

    Bak, E. N.; Merrison, J. P.; Jensen, S. K.; Nørnberg, P.; Finster, K.

    2014-07-01

    Laboratory simulations show that wind-eroded silicate can be a source of hydrogen peroxide. The ubiquitous, fine-grained silicate dust might thus explain the oxidizing properties of the martian soil and affect the preservation of organic compounds.

  20. An iso-erodent map Imo state of Nigeria | Madubuike | International ...

    African Journals Online (AJOL)

    Among inputs/resources often needed for erosion risk assessment of a region is the iso-erodent map of the region. This is a map showing areas of equal erosion potentials in the region. As Imo and Abia states of Nigeria lie in a high erosion region of the country, it was decided in this work to produce an iso-erodent map of ...

  1. Soil erodibility in Europe: a high-resolution dataset based on LUCAS.

    Science.gov (United States)

    Panagos, Panos; Meusburger, Katrin; Ballabio, Cristiano; Borrelli, Pasqualle; Alewell, Christine

    2014-05-01

    The greatest obstacle to soil erosion modelling at larger spatial scales is the lack of data on soil characteristics. One key parameter for modelling soil erosion is the soil erodibility, expressed as the K-factor in the widely used soil erosion model, the Universal Soil Loss Equation (USLE) and its revised version (RUSLE). The K-factor, which expresses the susceptibility of a soil to erode, is related to soil properties such as organic matter content, soil texture, soil structure and permeability. With the Land Use/Cover Area frame Survey (LUCAS) soil survey in 2009 a pan-European soil dataset is available for the first time, consisting of around 20,000 points across 25 Member States of the European Union. The aim of this study is the generation of a harmonised high-resolution soil erodibility map (with a grid cell size of 500 m) for the 25 EU Member States. Soil erodibility was calculated for the LUCAS survey points using the nomograph of Wischmeier and Smith (1978). A Cubist regression model was applied to correlate spatial data such as latitude, longitude, remotely sensed and terrain features in order to develop a high-resolution soil erodibility map. The mean K-factor for Europe was estimated at 0.032 thahha(-1)MJ(-1)mm(-1) with a standard deviation of 0.009 thahha(-1)MJ(-1)mm(-1). The yielded soil erodibility dataset compared well with the published local and regional soil erodibility data. However, the incorporation of the protective effect of surface stone cover, which is usually not considered for the soil erodibility calculations, resulted in an average 15% decrease of the K-factor. The exclusion of this effect in K-factor calculations is likely to result in an overestimation of soil erosion, particularly for the Mediterranean countries, where highest percentages of surface stone cover were observed. Copyright © 2014. Published by Elsevier B.V.

  2. Erodibility of waste (Loess) soils from construction sites under water and wind erosional forces.

    Science.gov (United States)

    Tanner, Smadar; Katra, Itzhak; Argaman, Eli; Ben-Hur, Meni

    2018-03-01

    Excess soils from construction sites (waste soils) become a problem when exposed to soil erosion by water or wind. Understanding waste soil erodibility can contribute to its proper reuse for various surface applications. The general objective of the study was to provide a better understanding of the effects of soil properties on erodibility of waste soils excavated from various depths in a semiarid region under rainfall and wind erosive forces. Soil samples excavated from the topsoil (0-0.3m) and subsoil layers (0.3-0.9 and >1m depths) were subjected to simulated rainfall and wind. Under rainfall erosive forces, the subsoils were more erodible than the topsoil, in contrast to the results obtained under wind erosive forces. Exchangeable sodium percentage was the main factor controlling soil erodibility (K i ) under rainfall, and a significant logarithmic regression line was found between these two parameters. In addition, a significant, linear regression was found between K i and slaking values for the studied soil samples, suggesting that the former can be predicted from the latter. Soil erodibility under wind erosion force was controlled mainly by the dry aggregate characteristics (mean weight diameter and aggregate density): their higher values in the subsoil layers resulted in lower soil erodibility compared to the topsoil. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. A Physically—Based Geometry Model for Transport Distance Estimation of Rainfall-Eroded Soil Sediment

    Directory of Open Access Journals (Sweden)

    Qian-Gui Zhang

    2016-01-01

    Full Text Available Estimations of rainfall-induced soil erosion are mostly derived from the weight of sediment measured in natural runoff. The transport distance of eroded soil is important for evaluating landscape evolution but is difficult to estimate, mainly because it cannot be linked directly to the eroded sediment weight. The volume of eroded soil is easier to calculate visually using popular imaging tools, which can aid in estimating the transport distance of eroded soil through geometry relationships. In this study, we present a straightforward geometry model to predict the maximum sediment transport distance incurred by rainfall events of various intensity and duration. In order to verify our geometry prediction model, a series of experiments are reported in the form of a sediment volume. The results show that cumulative rainfall has a linear relationship with the total volume of eroded soil. The geometry model can accurately estimate the maximum transport distance of eroded soil by cumulative rainfall, with a low root-mean-square error (4.7–4.8 and a strong linear correlation (0.74–0.86.

  4. Ethylene and jasmonic acid act as negative modulators during mutualistic symbiosis between Laccaria bicolor and Populus roots.

    Science.gov (United States)

    Plett, Jonathan M; Khachane, Amit; Ouassou, Malika; Sundberg, Björn; Kohler, Annegret; Martin, Francis

    2014-04-01

    The plant hormones ethylene, jasmonic acid and salicylic acid have interconnecting roles during the response of plant tissues to mutualistic and pathogenic symbionts. We used morphological studies of transgenic- or hormone-treated Populus roots as well as whole-genome oligoarrays to examine how these hormones affect root colonization by the mutualistic ectomycorrhizal fungus Laccaria bicolor S238N. We found that genes regulated by ethylene, jasmonic acid and salicylic acid were regulated in the late stages of the interaction between L. bicolor and poplar. Both ethylene and jasmonic acid treatments were found to impede fungal colonization of roots, and this effect was correlated to an increase in the expression of certain transcription factors (e.g. ETHYLENE RESPONSE FACTOR1) and a decrease in the expression of genes associated with microbial perception and cell wall modification. Further, we found that ethylene and jasmonic acid showed extensive transcriptional cross-talk, cross-talk that was opposed by salicylic acid signaling. We conclude that ethylene and jasmonic acid pathways are induced late in the colonization of root tissues in order to limit fungal growth within roots. This induction is probably an adaptive response by the plant such that its growth and vigor are not compromised by the fungus. © 2013 The Authors New Phytologist © 2013 New Phytologist Trust.

  5. Differential Sharing of Chemical Cues by Social Parasites Versus Social Mutualists in a Three-Species Symbiosis.

    Science.gov (United States)

    Emery, Virginia J; Tsutsui, Neil D

    2016-04-01

    Chemical recognition systems are crucial for maintaining the unity of social insect colonies. It has been proposed that colonies form a common chemical signature, called the gestalt odor, which is used to distinguish colony members and non-members. This chemical integration is achieved actively through social interactions such as trophallaxis and allogrooming, or passively such as through exposure to common nest material. When colonies are infiltrated by social parasites, the intruders often use some form of chemical mimicry. However, it is not always clear how this chemical mimicry is accomplished. Here, we used a three-species nesting symbiosis to test the differences in chemical integration of mutualistic (parabiotic) and parasitic ant species. We found that the parasite (Solenopsis picea) obtains chemical cues from both of the two parabiotic host ant species. However, the two parabiotic species (Crematogaster levior and Camponotus femoratus) maintain species-specific cues, and do not acquire compounds from the other species. Our findings suggest that there is a fundamental difference in how social mutualists and social parasites use chemicals to integrate themselves into colonies.

  6. Cutaneous Squamous Cell Carcinoma with Invasion through Ear Cartilage

    Directory of Open Access Journals (Sweden)

    Julie Boisen

    2016-01-01

    Full Text Available Cutaneous squamous cell carcinoma of the ear represents a high-risk tumor location with an increased risk of metastasis and local tissue invasion. However, it is uncommon for these cancers to invade through nearby cartilage. Cartilage invasion is facilitated by matrix metalloproteases, specifically collagenase 3. We present the unusual case of a 76-year-old man with an auricular squamous cell carcinoma that exhibited full-thickness perforation of the scapha cartilage. Permanent sections through the eroded cartilage confirmed tumor invasion extending to the posterior ear skin.

  7. Invasive acacias experience higher ant seed removal rates at the invasion edges

    Directory of Open Access Journals (Sweden)

    D. Montesinos

    2012-06-01

    Full Text Available Seed dispersal is a key process for the invasion of new areas by exotic species. Introduced plants often take advantage of native generalist dispersers. Australian acacias are primarily dispersed by ants in their native range and produce seeds bearing a protein and lipid rich reward for ant mutualists (elaiosome. Nevertheless, the role of myrmecochory in the expansion of Australian acacias in European invaded areas is still not clear. We selected one European population of Acacia dealbata and another of A. longifolia and offered elaiosome-bearing and elaiosome-removed seeds to local ant communities. For each species, seeds were offered both in high-density acacia stands and in low-density invasion edges. For both acacia species, seed removal was significantly higher at the low-density edges. For A. longifolia, manual elimination of elaiosomes reduced the chance of seed removal by 80% in the low-density edges, whereas it made no difference on the high-density stands. For A. dealbata, the absence of elaiosome reduced seed removal rate by 52%, independently of the acacia density. Our data suggests that invasive acacias have found effective ant seed dispersers in Europe and that the importance of such dispersers is higher at the invasion edges.

  8. Large-scale assessment of commensalistic–mutualistic associations between African birds and herbivorous mammals using internet photos

    Science.gov (United States)

    Hadrava, Jiří; Albrecht, Tomáš; Tryjanowski, Piotr

    2018-01-01

    Birds sitting or feeding on live large African herbivorous mammals are a visible, yet quite neglected, type of commensalistic–mutualistic association. Here, we investigate general patterns in such relationships at large spatial and taxonomic scales. To obtain large-scale data, an extensive internet-based search for photos was carried out on Google Images. To characterize patterns of the structural organization of commensalistic–mutualistic associations between African birds and herbivorous mammals, we used a network analysis approach. We then employed phylogenetically-informed comparative analysis to explore whether features of bird visitation of mammals, i.e., their mean number, mass and species richness per mammal species, are shaped by a combination of host mammal (body mass and herd size) and environmental (habitat openness) characteristics. We found that the association web structure was only weakly nested for commensalistic as well as for mutualistic birds (oxpeckers Buphagus spp.) and African mammals. Moreover, except for oxpeckers, nestedness did not differ significantly from a null model indicating that birds do not prefer mammal species which are visited by a large number of bird species. In oxpeckers, however, a nested structure suggests a non-random assignment of birds to their mammal hosts. We also identified some new or rare associations between birds and mammals, but we failed to find several previously described associations. Furthermore, we found that mammal body mass positively influenced the number and mass of birds observed sitting on them in the full set of species (i.e., taking oxpeckers together with other bird species). We also found a positive correlation between mammal body mass and mass of non-oxpecker species as well as oxpeckers. Mammal herd size was associated with a higher mass of birds in the full set of species as well as in non-oxpecker species, and mammal species living in larger herds also attracted more bird species in the

  9. Soil Erodibility for Water Pollution Management of Melaka Watershed in Peninsular Malaysia

    Directory of Open Access Journals (Sweden)

    Md. Ibrahim Adham

    2015-07-01

    Full Text Available The relationships between surface runoffand soil erodibility are significant in water pollution and watershed management practices. Land use pattern, soil series and slope percentage are also major factors to develop the relationships. Daily rainfall data were collected and analyzed for variations in precipitation for calculating the surface runoff of these watersheds and surface runoff map was produced by GIS tools. Tew equation was utilized to predict soil erodibility of watershed soils.Results indicated that the weighted curve number varies from 82 to 85 and monthly runoff 23% to 30% among the five watersheds. Soil erodibility varies from 0.038 to 0.06 ton/ha (MJ.mm/ha/h. Linau-Telok-Local Alluvium, Malacca-Munchong, Munchong-Malacca-Serdang and Malacca-Munchong-Tavy are the dominant soil series of this region having the average soil erodibility of about 0.042 ton/ha (MJ.mm/ha/h. The main focus of this study is to provide the information of soil erodibility to reduce the water pollution of a watershed.

  10. The effect of metapleural gland secretion on the growth of a mutualistic bacterium on the cuticle of leaf-cutting ants

    DEFF Research Database (Denmark)

    Poulsen, Michael; Bot, Adrianne N M; Boomsma, Jacobus J

    2003-01-01

    In Acromyrmex octospinosus leaf-cutting ants the metapleural glands produce an array of antibiotic compounds that serve as a general defence against unwanted microbes on the cuticle. Leaf-cutting ants also grow mutualistic Pseudonocardiaceae bacteria on their cuticle that produce antibiotics...

  11. Effects of climate change on a mutualistic coastal species: Recovery from typhoon damages and risks of population erosion.

    Science.gov (United States)

    Chiu, Yu-Ting; Bain, Anthony; Deng, Shu-Lin; Ho, Yi-Chiao; Chen, Wen-Hsuan; Tzeng, Hsy-Yu

    2017-01-01

    Presently, climate change has increased the frequency of extreme meteorological events such as tropical cyclones. In the western Pacific basin, these cyclones are called typhoons, and in this area, around Taiwan Island, their frequency has almost doubled since 2000. When approaching landmasses, typhoons have devastating effects on coastal vegetation. The increased frequency of these events has challenged the survival of coastal plant species and their posttyphoon recovery. In this study, a population of coastal gynodioecious Ficus pedunculosa var. mearnsii (Mearns fig) was surveyed for two years to investigate its recovery after Typhoon Morakot, which occurred in August 2009. Similar to all the Ficus species, the Mearns fig has an obligate mutualistic association with pollinating fig wasp species, which requires syconia (the closed Ficus inflorescence) to complete its life cycle. Moreover, male gynodioecious fig species produces both pollen and pollen vectors, whereas the female counterpart produces only seeds. The recovery of the Mearns fig was observed to be rapid, with the production of both leaves and syconia. The syconium:leaf ratio was greater for male trees than for female trees, indicating the importance of syconium production for the wasp survival. Pollinating wasps live for approximately 1 day; therefore, receptive syconia are crucial. Every typhoon season, few typhoons pass by the coasts where the Mearns fig grows, destroying all the leaves and syconia. In this paper, we highlight the potential diminution of the fig population that can lead to the extinction of the mutualistic pair of species. The effects of climate change on coastal species warrant wider surveys.

  12. Effects of climate change on a mutualistic coastal species: Recovery from typhoon damages and risks of population erosion.

    Directory of Open Access Journals (Sweden)

    Yu-Ting Chiu

    Full Text Available Presently, climate change has increased the frequency of extreme meteorological events such as tropical cyclones. In the western Pacific basin, these cyclones are called typhoons, and in this area, around Taiwan Island, their frequency has almost doubled since 2000. When approaching landmasses, typhoons have devastating effects on coastal vegetation. The increased frequency of these events has challenged the survival of coastal plant species and their posttyphoon recovery. In this study, a population of coastal gynodioecious Ficus pedunculosa var. mearnsii (Mearns fig was surveyed for two years to investigate its recovery after Typhoon Morakot, which occurred in August 2009. Similar to all the Ficus species, the Mearns fig has an obligate mutualistic association with pollinating fig wasp species, which requires syconia (the closed Ficus inflorescence to complete its life cycle. Moreover, male gynodioecious fig species produces both pollen and pollen vectors, whereas the female counterpart produces only seeds. The recovery of the Mearns fig was observed to be rapid, with the production of both leaves and syconia. The syconium:leaf ratio was greater for male trees than for female trees, indicating the importance of syconium production for the wasp survival. Pollinating wasps live for approximately 1 day; therefore, receptive syconia are crucial. Every typhoon season, few typhoons pass by the coasts where the Mearns fig grows, destroying all the leaves and syconia. In this paper, we highlight the potential diminution of the fig population that can lead to the extinction of the mutualistic pair of species. The effects of climate change on coastal species warrant wider surveys.

  13. Textural characteristics and sedimentary environment of sediment at eroded and deposited regions in the severely eroded coastline of Batu Pahat, Malaysia.

    Science.gov (United States)

    Wan Mohtar, Wan Hanna Melini; Nawang, Siti Aminah Bassa; Abdul Maulud, Khairul Nizam; Benson, Yannie Anak; Azhary, Wan Ahmad Hafiz Wan Mohamed

    2017-11-15

    This study investigates the textural characteristics of sediments collected at eroded and deposited areas of highly severed eroded coastline of Batu Pahat, Malaysia. Samples were taken from systematically selected 23 locations along the 67km stretch of coastline and are extended to the fluvial sediments of the main river of Batu Pahat. Grain size distribution analysis was conducted to identify its textural characteristics and associated sedimentary transport behaviours. Sediments obtained along the coastline were fine-grained material with averaged mean size of 7.25 ϕ, poorly sorted, positively skewed and has wide distributions. Samples from eroded and deposition regions displayed no distinctive characteristics and exhibited similar profiles. The high energy condition transported the sediments as suspension, mostly as pelagic and the sediments were deposited as shallow marine and agitated deposits. The fluvial sediments of up to 3km into the river have particularly similar profile of textural characteristics with the neighbouring marine sediments from the river mouth. Profiles were similar with marine sediments about 3km opposite the main current and can go up to 10km along the current of Malacca Straits. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Water and dissolved carbon transport in an eroding soil landscape using column experiments

    DEFF Research Database (Denmark)

    Rieckh, Helene; Gerke, Horst; Glæsner, Nadia

    2014-01-01

    In the hummocky ground moraine soil landscape, a spatial continuum of more or less eroded soils developed from till under intensive agricultural cultivation. Water flow and solute transport are affected by the variable soil structural and pedological developments, which are posing a challenge...... for flux estimation. The objective of this study was to investigate transport of water, dissolved organic (DOC), and particulate carbon (PC) through soil profiles of an eroded Haplic Luvisol and a heavily eroded Haplic Regosol. We studied 5 soil horizons in three replicates each: Ap (0-20 cm) and E (20...... boundary. Breakthrough curves for a pre-applied tracer (Br-) on the soil surface and a tracer applied with irrigation water (3H2O) were modeled analytically using CXTFIT. The heterogeneity of the Luvisol horizons was generally higher than that of the Regosol horizons, which relates to the higher...

  15. MAPPING ERODED AREAS ON MOUNTAIN GRASSLAND WITH TERRESTRIAL PHOTOGRAMMETRY AND OBJECT-BASED IMAGE ANALYSIS

    Directory of Open Access Journals (Sweden)

    A. Mayr

    2016-06-01

    Full Text Available In the Alps as well as in other mountain regions steep grassland is frequently affected by shallow erosion. Often small landslides or snow movements displace the vegetation together with soil and/or unconsolidated material. This results in bare earth surface patches within the grass covered slope. Close-range and remote sensing techniques are promising for both mapping and monitoring these eroded areas. This is essential for a better geomorphological process understanding, to assess past and recent developments, and to plan mitigation measures. Recent developments in image matching techniques make it feasible to produce high resolution orthophotos and digital elevation models from terrestrial oblique images. In this paper we propose to delineate the boundary of eroded areas for selected scenes of a study area, using close-range photogrammetric data. Striving for an efficient, objective and reproducible workflow for this task, we developed an approach for automated classification of the scenes into the classes grass and eroded. We propose an object-based image analysis (OBIA workflow which consists of image segmentation and automated threshold selection for classification using the Excess Green Vegetation Index (ExG. The automated workflow is tested with ten different scenes. Compared to a manual classification, grass and eroded areas are classified with an overall accuracy between 90.7% and 95.5%, depending on the scene. The methods proved to be insensitive to differences in illumination of the scenes and greenness of the grass. The proposed workflow reduces user interaction and is transferable to other study areas. We conclude that close-range photogrammetry is a valuable low-cost tool for mapping this type of eroded areas in the field with a high level of detail and quality. In future, the output will be used as ground truth for an area-wide mapping of eroded areas in coarser resolution aerial orthophotos acquired at the same time.

  16. Morphology of ductile metals eroded by a jet of spherical particles impinging at normal incidence

    Science.gov (United States)

    Veerabhadra Rao, P.; Young, S. G.; Buckley, D. H.

    1983-01-01

    Scanning electron microscopy and energy-dispersive X-ray spectroscopy are used, together with surface profile measurements, in the present morphological study of the erosion of an aluminum alloy and copper by the normal impact of spherical glass erodent particles. The morphology of the damage pattern is a manifestation of the flow pattern of erodent particles, and yields insight into the mechanisms that may be active at different stages of erosion. The simultaneous appearance of radial cracks and concentric rings is reported, together with wave crests which contain an accumulation of metallic flakes. A preliminary analysis is advanced to explain the formation of the various damage patterns observed.

  17. Wind-eroded silicate as a source of hydrogen peroxide on Mars

    DEFF Research Database (Denmark)

    Bak, Ebbe Norskov; Merrison, Jonathan P.; Jensen, Svend Knak

    -sists of silicates [4] that due to wind erosion has a very fine grained texture. Based on the composition of the surface material and investigations showing that crushing of silicates can give rise to reactive oxygen species [5], we hypothesized that wind erosion of silicates can explain the reactivity of Martian...... soil. Wind-erosion of silicate could thus be one of several causes of the soil’s reactivity. As our experiments show, the globally distributed wind eroded silicate dust can lead to the production of hydrogen peroxide which might explain the reactivity of the Martian soil. The reactivity of eroded...

  18. Continuum modeling of ion-beam eroded surfaces under normal incidence: Impact of stochastic fluctuations

    International Nuclear Information System (INIS)

    Dreimann, Karsten; Linz, Stefan J.

    2010-01-01

    Graphical abstract: Deterministic surface pattern (left) and its stochastic counterpart (right) arising in a stochastic damped Kuramoto-Sivashinsky equation that serves as a model equation for ion-beam eroded surfaces and is systematically investigated. - Abstract: Using a recently proposed field equation for the surface evolution of ion-beam eroded semiconductor target materials under normal incidence, we systematically explore the impact of additive stochastic fluctuations that are permanently present during the erosion process. Specifically, we investigate the dependence of the surface roughness, the underlying pattern forming properties and the bifurcation behavior on the strength of the fluctuations.

  19. Glyphosate and AMPA distribution in wind-eroded sediment derived from loess soil

    NARCIS (Netherlands)

    Martins Bento, Celia; Goossens, Dirk; Rezaei, Mahrooz; Riksen, M.J.P.M.; Mol, J.G.J.; Ritsema, C.J.; Geissen, V.

    2017-01-01

    Glyphosate is one of the most used herbicides in agricultural lands worldwide. Wind-eroded sediment and dust, as an environmental transport pathway of glyphosate and of its main metabolite aminomethylphosphonic acid (AMPA), can result in environmental- and human exposure far beyond the agricultural

  20. Erodibility of a mixed mudflat dominated by microphytobenthos and Cerastoderma edule, East Frisian Wadden Sea, Germany

    DEFF Research Database (Denmark)

    Andersen, Thorbjørn Joest; Lanuru, Mahatma; van Bernem, Carlo

    2010-01-01

    Sediment erodibility and a range of physical and biological parameters were measured at an intertidal site in the German Wadden Sea area in June, September and November 2002 and February and April 2003 in order to examine the influence of macrozoobenthos and microphytobenthos on sediment erodibil......Sediment erodibility and a range of physical and biological parameters were measured at an intertidal site in the German Wadden Sea area in June, September and November 2002 and February and April 2003 in order to examine the influence of macrozoobenthos and microphytobenthos on sediment...... erodibility and the temporal variation. The study site was a mixed mudflat situated in the mesotidal Baltrum-Langeoog tidal basin at the East Frisian barrier coast. The mud content at the site was about 35% and the filter-feeding cockle Cerastoderma edule was the dominating macrozoobenthic species (by biomass...... of C. edule will therefore probably increase the content of fine-grained sediments at the surface compared to an abiotic situation. Increasing the amount of fine-grained material in mixed sediments has previously been shown to reduce the erodibility of the sediments and C. edule will therefore...

  1. Eroded dentin does not jeopardize the bond strength of adhesive restorative materials

    Directory of Open Access Journals (Sweden)

    Janaina Barros Cruz

    2012-08-01

    Full Text Available This in vitro study evaluated the bond strength of adhesive restorative materials to sound and eroded dentin. Thirty-six bovine incisors were embedded in acrylic resin and ground to obtain flat buccal dentin surfaces. Specimens were randomly allocated in 2 groups: sound dentin (immersion in artificial saliva and eroded dentin (pH cycling model - 3× / cola drink for 7 days. Specimens were then reassigned according to restorative material: glass ionomer cement (KetacTM Molar Easy Mix, resin-modified glass ionomer cement (VitremerTM or adhesive system with resin composite (Adper Single Bond 2 + Filtek Z250. Polyethylene tubes with an internal diameter of 0.76 mm were placed over the dentin and filled with the material. The microshear bond test was performed after 24 h of water storage at 37ºC. The failure mode was evaluated using a stereomicroscope (400×. Bond strength data were analyzed with two-way ANOVA and Tukey's post hoc tests (α = 0.05. Eroded dentin showed bond strength values similar to those for sound dentin for all materials. The adhesive system showed the highest bond strength values, regardless of the substrate (p < 0.0001. For all groups, the adhesive/mixed failure prevailed. In conclusion, adhesive materials may be used in eroded dentin without jeopardizing the bonding quality. It is preferable to use an etch-and-rinse adhesive system because it shows the highest bond strength values compared with the glass ionomer cements tested.

  2. Turbidity current hydraulics and sediment deposition in erodible sinuous channels: Laboratory experiments and numerical simulations

    NARCIS (Netherlands)

    Janocko, M.; Cartigny, M.J.B.; Nemec, W.; Hansen, E.W.M.

    2013-01-01

    This study explores the relationship between the hydraulics of turbidity currents in erodible sinuous channels and the resulting intra-channel sediment depocentres (channel bars). Four factors are considered to exert critical control on sedimentation in sinuous submarine channels: (1) the

  3. Incorporation of Fine-Grained Sediment Erodibility Measurements into Sediment Transport Modeling, Capitol Lake, Washington

    Science.gov (United States)

    Stevens, Andrew W.; Gelfenbaum, Guy; Elias, Edwin; Jones, Craig

    2008-01-01

    Capitol Lake was created in 1951 with the construction of a concrete dam and control gate that prevented salt-water intrusion into the newly formed lake and regulated flow of the Deschutes River into southern Puget Sound. Physical processes associated with the former tidally dominated estuary were altered, and the dam structure itself likely caused an increase in retention of sediment flowing into the lake from the Deschutes River. Several efforts to manage sediment accumulation in the lake, including dredging and the construction of sediment traps upriver, failed to stop the lake from filling with sediment. The Deschutes Estuary Feasibility Study (DEFS) was carried out to evaluate the possibility of removing the dam and restoring estuarine processes as an alternative ongoing lake management. An important component of DEFS was the creation of a hydrodynamic and sediment transport model of the restored Deschutes Estuary. Results from model simulations indicated that estuarine processes would be restored under each of four restoration alternatives, and that over time, the restored estuary would have morphological features similar to the predam estuary. The model also predicted that after dam-removal, a large portion of the sediment eroded from the lake bottom would be deposited near the Port of Olympia and a marina located in lower Budd Inlet seaward of the present dam. The volume of sediment transported downstream was a critical piece of information that managers needed to estimate the total cost of the proposed restoration project. However, the ability of the model to predict the magnitude of sediment transport in general and, in particular, the volume of sediment deposition in the port and marina was limited by a lack of information on the erodibility of fine-grained sediments in Capitol Lake. Cores at several sites throughout Capitol Lake were collected between October 31 and November 1, 2007. The erodibility of sediments in the cores was later determined in the

  4. Photorefractive keratectomy (PRK) at 193 nm using an erodible mask: new developments and clinical progress

    Science.gov (United States)

    Gordon, Michael; Seiler, Theo; Carey, Joseph P.; Friedman, Marc D.; Johnsson, N. M. F.; King, Michael C.; Muller, David F.

    1993-06-01

    This paper reports on our progress using an erodible mask to perform photorefractive keratectomy (PRK) for the correction of myopic astigmatism. We describe modifications to the mask, the mask eye cup and the surgical microscope aimed at simplifying the procedure and improving the ergonomics of the hardware. We report the clinical results of the post-op exam for 20 patients who have undergone PRK for myopic astigmatism under a Phase IIA study. The results compare favorably with an earlier Phase IIA study for performing PRK with a computer-controlled iris. Most important, the clinical data show the absence of any significant corneal haze and no significant decrease in spectacle corrected visual acuity. Although more long term follow-up is needed, the preliminary results support the safety and effectiveness of using an erodible mask to perform PRK for myopic astigmatism.

  5. Testing the effect of a microbial-based soil amendment on aggregate stability and erodibility

    DEFF Research Database (Denmark)

    Malozo, Mponda; Iversen, Bo Vangsø; Heckrath, Goswin Johann

    to the rainfall-runoff experiment where the microbial-based product had a clear effect on soil erodibility. In relation to measurement of aggregate stability as well as clay dispersion, the picture was less clear. Especially for the sandy Tanzania soil with a low content of organic matter, a clear effect was seen...... aggregate stability and erodibility. Two commercial products, gypsum and a microbial-based solution were used for the experiment and were tested on two Danish sandy loamy soils as well on a sandy soil from Tanzania. The carrier of the microbial-based product, a glycerol solution, was tested as well....... In the laboratory, soils were treated with the soil amendments in a two-step procedure at controlled water contents following aerobic incubation in closed containers. Water-aggregate stability and clay dispersion were measured on soil aggregates less than 8 mm in diameter. Aggregate stability was measured...

  6. Effects of human pharmaceuticals on cytotoxicity, EROD activity and ROS production in fish hepatocytes

    International Nuclear Information System (INIS)

    Laville, N.; Aiet-Aiessa, S.; Gomez, E.; Casellas, C.; Porcher, J.M.

    2004-01-01

    Pharmaceuticals are found in the aquatic environment but their potential effects on non-target species like fish remain unknown. This in vitro study is a first approach in the toxicity assessment of human drugs on fish. Nine pharmaceuticals were tested on two fish hepatocyte models: primary cultures of rainbow trout hepatocytes (PRTH) and PLHC-1 fish cell line. Cell viability, interaction with cytochrome P450 1A (CYP1A) enzyme and oxidative stress were assessed by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrasodium bromide tetrazolium (MTT), 7-ethoxyresorufin-o-deethylase (EROD) and dichlorofluorescein (DCFH-DA) assays, respectively. The tested drugs were clofibrate (CF), fenofibrate (FF), carbamazepine (CBZ), fluoxetine (FX), diclofenac (DiCF), propranolol (POH), sulfamethoxazole (SFX), amoxicillin (AMX) and gadolinium chloride (GdCl 3 ). All substances were cytotoxic, except AMX at concentration up to 500 μM. The calculated MTT EC 50 values ranged from 2 μM (CF) to 651 μM (CBZ) in PLHC-1, and from 53 μM (FF) to 962 μM (GdCl 3 ) in PRTH. CF, FF, and FX were the most cytotoxic drugs and induced oxidative stress before being cytotoxic. Compared to hepatocytes from human and dog, fish hepatocytes seemed to be more susceptible to the peroxisome proliferators (PPs) CF and FF. In PLHC-1 cells none of the tested drugs induced the EROD activity whereas POH appeared as a weak EROD inducer in PRTH. Moreover, in PRTH, SFX, DiCF, CBZ and to a lesser extend, FF and CF inhibited the basal EROD activity at clearly sublethal concentrations which may be of concern at the biological and chemical levels in a multipollution context

  7. Assessment of Ground Water Quality in and around Gobichettipalayam Town Erode District, Tamilnadu

    OpenAIRE

    P. N. Palanisamy; A. Geetha; M. Sujatha; P. Sivakumar; K. Karunakaran

    2007-01-01

    Ground water samples collected from different localities in and around Gobichettipalayam town, Erode District, Tamil Nadu were analyzed for their physico- chemical characteristics. This analysis result was compared with the WHO & ICMR standards of drinking water quality parameters with the following water quality parameters namely pH, Electrical conductivity, CN-, Cl-, SO42-, Na+, K+, Ca & Mg in CaCO3 equivalents, phenolphthalein alkalinity, hydroxide alkalinity, carbonate alkalinity, bicarbo...

  8. Erodibility of surface-mine spoil banks in southeastern Ohio : an approximation

    Energy Technology Data Exchange (ETDEWEB)

    McKenzie, C D; Studlick, J R.J.

    1979-07-01

    Measurements of accumulated sediment in inter-bank basins of unreclaimed strip mines determined the average annual site loss from unvegetated, 18-year-old spoil banks. Assuming that the universal soil loss equation (USLE) can be used to estimate sediment yield from strip mine slopes, the topographic factor in the USLE was determined in 2 ways, and values for erodibility well calculated. The technique is applicable to unreclaimed mines where inter-bank basins trap all slope-derived sediment.

  9. The Influence of Eroded Blades on Wind Turbine Performance Using Numerical Simulations

    Directory of Open Access Journals (Sweden)

    Matthias Schramm

    2017-09-01

    Full Text Available During their operation, wind turbine blades are eroded due to rain and hail, or they are contaminated with insects. Since the relative inflow velocity is higher at the outer than at the inner part of the blades, erosion occurs mostly at the outer blade region. In order to prevent strong erosion, it is possible to install a leading edge protection, which can be applied to the blades after the initial installation, but changes the shape of the initial airfoil sections. It is unclear how this modification influences the aerodynamic performance of the turbine. Hence, it is investigated in this work. The NREL 5 MW turbine is simulated with clean and eroded blades, which are compared to coated blades equipped with leading edge protection. Aerodynamic polars are generated by means of Computational Fluid Dynamics, and load calculations are conducted using the blade element momentum theory. The analysis in this work shows that, compared to clean rotor blades, the worse aerodynamic behaviour of strongly eroded blades can lead to power losses of 9 % . In contrast, coated blades only have a small impact on the turbine power of less than 1 % .

  10. Predicting of soil erosion with regarding to rainfall erosivity and soil erodibility

    Science.gov (United States)

    Suif, Zuliziana; Razak, Mohd Amirun Anis Ab; Ahmad, Nordila

    2018-02-01

    The soil along the hill and slope are wearing away due to erosion and it can take place due to occurrence of weak and heavy rainfall. The aim of this study is to predict the soil erosion degree in Universiti Pertahanan Nasional Malaysia (UPNM) area focused on two major factor which is soil erodibility and rainfall erosivity. Soil erodibility is the possibilities of soil to detach and carried away during rainfall and runoff. The "ROM" scale was used in this study to determine the degree of soil erodibility, namely low, moderate, high, and very high. As for rainfall erosivity, the erosive power caused by rainfall that cause soil loss. A daily rainfall data collected from January to April was analyzed by using ROSE index classification to identify the potential risk of soil erosion. The result shows that the soil erodibilty are moderate at MTD`s hill, high at behind of block Lestari and Landslide MTD hill, and critical at behind the mess cadet. While, the highest rainfall erosivity was recorded in March and April. Overall, this study would benefit the organization greatly in saving cost in landslide protection as relevant authorities can take early measures repairing the most affected area of soil erosion.

  11. Influence of bleaching agents on surface roughness of sound or eroded dental enamel specimens.

    Science.gov (United States)

    Azrak, Birgül; Callaway, Angelika; Kurth, Petra; Willershausen, Brita

    2010-12-01

    The aim of the present in vitro study was to assess the effect of bleaching agents on eroded and sound enamel specimens. Enamel specimens prepared from human permanent anterior teeth were incubated with different bleaching agents containing active ingredients as 7.5 or 13.5% hydrogen peroxide or 35% carbamide peroxide, ranging in pH from 4.9 to 10.8. The effect of the tooth whitening agents on surface roughness was tested for sound enamel surfaces as well as for eroded enamel specimens. To provoke erosive damage, the enamel specimens were incubated for 10 hours with apple juice (pH = 3.4). Afterwards, pretreated and untreated dental slices were incubated with one of the bleaching agents for 10 hours. The surface roughness (R(a)) of all enamel specimens (N = 80) was measured using an optical profilometric device. A descriptive statistical analysis of the R(a) values was performed. The study demonstrated that exposure to an acidic bleaching agent (pH = 4.9) resulted in a higher surface roughness (p = 0.043) than treatment with a high peroxide concentration (pH = 6.15). If the enamel surface was previously exposed to erosive beverages, subsequent bleaching may enhance damage to the dental hard tissue. Bleaching agents with a high concentration of peroxide or an acidic pH can influence the surface roughness of sound or eroded enamel. © 2010, COPYRIGHT THE AUTHORS. JOURNAL COMPILATION © 2010, WILEY PERIODICALS, INC.

  12. Frijolito Watershed: Integrated investigations of a rapidly eroding pinyon-juniper hillslope

    International Nuclear Information System (INIS)

    Wilcox, B.P.; Pitlick, J.

    1995-01-01

    The dramatic acceleration of erosion associated with the expansion of pinyon-juniper woodlands over the past 100 years has been widely recognized, but few process-based studies of this phenomenon have been undertaken. In an attempt to identify the underlying causes, and the factors that affect erosion processes, we have initiated an interdisciplinary study of a rapidly eroding pinyon-juniper woodland in northern New Mexico. Since July 1993, we have collected data on runoff, erosion, and weather conditions from a 1-ha catchment study area and have conducted surveys of topography, soils, and vegetation. Our preliminary results indicate that although runoff makes up less than 10% of the annual water budget, runoff events - which are frequent in the summer - are capable of moving large amounts of sediment. We estimate that between July 1993 and October 1994, between 25,000 and 50,000 kg of sediment has eroded and been transported from the catchment. The information gained from such studies is essential to our ability to formulate effective strategies for managing these rapidly eroding woodlands

  13. Co-invading symbiotic mutualists of Medicago polymorpha retain high ancestral diversity and contain diverse accessory genomes.

    Science.gov (United States)

    Porter, Stephanie S; Faber-Hammond, Joshua J; Friesen, Maren L

    2018-01-01

    Exotic, invasive plants and animals can wreak havoc on ecosystems by displacing natives and altering environmental conditions. However, much less is known about the identities or evolutionary dynamics of the symbiotic microbes that accompany invasive species. Most leguminous plants rely upon symbiotic rhizobium bacteria to fix nitrogen and are incapable of colonizing areas devoid of compatible rhizobia. We compare the genomes of symbiotic rhizobia in a portion of the legume's invaded range with those of the rhizobium symbionts from across the legume's native range. We show that in an area of California the legume Medicago polymorpha has invaded, its Ensifer medicae symbionts: (i) exhibit genome-wide patterns of relatedness that together with historical evidence support host-symbiont co-invasion from Europe into California, (ii) exhibit population genomic patterns consistent with the introduction of the majority of deep diversity from the native range, rather than a genetic bottleneck during colonization of California and (iii) harbor a large set of accessory genes uniquely enriched in binding functions, which could play a role in habitat invasion. Examining microbial symbiont genome dynamics during biological invasions is critical for assessing host-symbiont co-invasions whereby microbial symbiont range expansion underlies plant and animal invasions. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  14. Belowground legacies of Pinus contorta invasion and removal result in multiple mechanisms of invasional meltdown.

    Science.gov (United States)

    Dickie, Ian A; St John, Mark G; Yeates, Gregor W; Morse, Chris W; Bonner, Karen I; Orwin, Kate; Peltzer, Duane A

    2014-01-01

    Plant invasions can change soil biota and nutrients in ways that drive subsequent plant communities, particularly when co-invading with belowground mutualists such as ectomycorrhizal fungi. These effects can persist following removal of the invasive plant and, combined with effects of removal per se, influence subsequent plant communities and ecosystem functioning. We used field observations and a soil bioassay with multiple plant species to determine the belowground effects and post-removal legacy caused by invasion of the non-native tree Pinus contorta into a native plant community. Pinus facilitated ectomycorrhizal infection of the co-occurring invasive tree, Pseudotsuga menziesii, but not conspecific Pinus (which always had ectomycorrhizas) nor the native pioneer Kunzea ericoides (which never had ectomycorrhizas). Pinus also caused a major shift in soil nutrient cycling as indicated by increased bacterial dominance, NO3-N (17-fold increase) and available phosphorus (3.2-fold increase) in soils, which in turn promoted increased growth of graminoids. These results parallel field observations, where Pinus removal is associated with invasion by non-native grasses and herbs, and suggest that legacies of Pinus on soil nutrient cycling thus indirectly promote invasion of other non-native plant species. Our findings demonstrate that multi-trophic belowground legacies are an important but hitherto largely unconsidered factor in plant community reassembly following invasive plant removal. Published by Oxford University Press on behalf of the Annals of Botany Company.

  15. Influence of biochar and terra preta substrates on wettability and erodibility of soils

    Science.gov (United States)

    Smetanova, A.; Dotterweich, M.; Diehl, D.; Ulrich, U.; Fohrer, N.

    2012-04-01

    Biochar (BC) and terra preta substrates (TPS) have recently been promoted as soil amendments suitable for soil stabilization, soil amelioration and long-term carbon sequestration. BC is a carbon-enriched substance produced by thermal decomposition of organic material. TPS is composed of liquid and solid organic matter, including BC, altered by acid-lactic fermentation. Their effect on wettability, soil erodibility and nutrient discharge through overland flow was studied by laboratory experiments. At water contents between 0 and 100% BC is water repellent, while TPS changes from a wettable into a repellent state. The 5 and 10 vol % mixtures of BC and 10 and 20 vol% mixtures of TPS with sand remain mainly wettable during drying but repellency maxima are shifted to higher water contents with respect to pure sand and are mainly of subcritical nature. The runoff response was dominated by infiltration properties of the substrates rather than their wettability.Only one mixtures (20% TPS) produced more runoff than sandy-loamy soil on a 15% slope at an intensity of 25 mm•h-1. The 10% BC decreased runoff by up to 40%. At higher rainfall intensities (45 and 55 mm•h-1) the 10% TPS7 was up to 35% less erodible than 10% BC. Despite the TPS containing more nutrients, nutrient discharge varied between types of nutrients, slopes, rainfall intensities and mixtures. The application of a 1 cm layer onto the soil surface instead of 10% mixtures is not recommended due to high nutrient concentrations in the runoff and the wettability of pure substrates. The usage of 10% BC in lowland areas with low frequency and low-intensity precipitation and 10% TPS7 in areas with higher rainfall intensities appears to be appropriate and commendable according to current results. However, together with reversibility of repellency, it needs to undergo further examination in the field under different environmental and land use conditions Key words: biochar, terra preta substrate, wettability

  16. Strength, shrinkage, erodibility and capillary flow characteristics of cement-treated recycled pavement materials

    Directory of Open Access Journals (Sweden)

    William Fedrigo

    2017-09-01

    Full Text Available Full-depth recycling with portland cement (FDR-PC has been widely used for pavement rehabilitation; however, doubts remain regarding factors affecting some properties of the recycled material. Aiming on quantifying the effects of those factors on the strength, drying shrinkage, erodibility, capillary rise and absorption of cement-treated mixtures (CTM of reclaimed asphalt pavement (RAP and graded crushed stone, tests were conducted considering different RAP contents, cement contents, compaction efforts and curing times. Cement addition increased the mixtures strength and reduced their erodibility and capillary flow characteristics, but increased shrinkage. Low cement contents resulted in acceptable strength for CTM, but in high capillary rise and absorption, not being suitable if the layer is exposed to long periods of water soaking. Higher compaction effort led to similar effects as cement addition, counterbalancing low cement contents usage and reducing costs and shrinkage cracking risk. Strength and shrinkage showed higher growth rates at early stages, and then precautions should be taken in order to avoid moisture loss. Increasing RAP content decreased strength; though, RAP effect on the other properties was statistically non-significant, indicating a similar behaviour as CTM without RAP. Considering the studied properties, the mixture with most satisfactory behaviour for field applications was identified. The results highlighted strength is not the only property to be considered when designing FDR-PC mixtures; although presenting acceptable strength, some mixtures may fail due to shrinkage cracking or erosion, when exposed to water content variations. Keywords: Full-depth recycling with cement, Strength, Drying shrinkage, Erodibility, Capillary rise, Absorption

  17. Co-introduction vs ecological fitting as pathways to the establishment of effective mutualisms during biological invasions.

    Science.gov (United States)

    Le Roux, Johannes J; Hui, Cang; Keet, Jan-Hendrik; Ellis, Allan G

    2017-09-01

    Contents 1354 I. 1354 II. 1355 III. 1357 IV. 1357 V. 1359 1359 References 1359 SUMMARY: Interactions between non-native plants and their mutualists are often disrupted upon introduction to new environments. Using legume-rhizobium mutualistic interactions as an example, we discuss two pathways that can influence symbiotic associations in such situations: co-introduction of coevolved rhizobia; and utilization of, and adaptation to, resident rhizobia, hereafter referred to as 'ecological fitting'. Co-introduction and ecological fitting have distinct implications for successful legume invasions and their impacts. Under ecological fitting, initial impacts may be less severe and will accrue over longer periods as novel symbiotic associations and/or adaptations may require fine-tuning over time. Co-introduction will have more profound impacts that will accrue more rapidly as a result of positive feedbacks between densities of non-native rhizobia and their coevolved host plants, in turn enhancing competition between native and non-native rhizobia. Co-introduction can further impact invasion outcomes by the exchange of genetic material between native and non-native rhizobia, potentially resulting in decreased fitness of native legumes. A better understanding of the roles of these two pathways in the invasion dynamics of non-native legumes is much needed, and we highlight some of the exciting research avenues it presents. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  18. Measuring the Amount of Eroded Soil and Surface Runoff Water in the Field

    OpenAIRE

    Abdulfatah Faraj Aboufayed

    2013-01-01

    Water erosion is the most important problems of the soil in the Jabel Nefusa area located in northwest of Libya; therefore, erosion station had been established in the Faculty of Veterinary and dryfarming research Station, University of the Al-japel Al-gharbi in Zentan. The length of the station is 72.6 feet, 6 feet width and the percentage of its slope is 3%. The station were established to measure the amount of soil eroded and amount of surface water produced during the seasons 95/96 and 96...

  19. Numerical simulation of evolutionary erodible bedforms using the particle finite element method

    Science.gov (United States)

    Bravo, Rafael; Becker, Pablo; Ortiz, Pablo

    2017-07-01

    This paper presents a numerical strategy for the simulation of flows with evolutionary erodible boundaries. The fluid equations are fully resolved in 3D, while the sediment transport is modelled using the Exner equation and solved with an explicit Lagrangian procedure based on a fixed 2D mesh. Flow and sediment are coupled in geometry by deforming the fluid mesh in the vertical direction and in velocities with the experimental sediment flux computed using the Meyer Peter Müller model. A comparison with real experiments on channels is performed, giving good agreement.

  20. Distribution of Shrubland and Grassland Soil Erodibility on the Loess Plateau

    Directory of Open Access Journals (Sweden)

    Xiao Zhang

    2018-06-01

    Full Text Available Soil erosion is one of the most severe problems facing environments and has increased throughout the 20th century. Soil erodibility (K-factor is one of the important indicators of land degradation, and many models have been used to estimate K values. Although soil erodibility has been estimated, the comparison of different models and their usage at a regional scale and, in particular, for different land use types, need more research. Four of the most widely distributed land use types were selected to analyze, including introduced and natural grassland, as well as introduced and natural shrubland. Soil particle size, soil organic matter and other relevant soil properties were measured to estimate soil erodibility in the Loess Plateau. The results show that: (1 the erosion productivity impact calculator (EPIC model and SHIRAZI model are both suitable for the Loess Plateau, while the SHIRAZI model has the advantage of fewer parameters; (2 introduced grassland has better ability to protect both the 0–5 cm soils and 5–20 cm soils, while the differences between introduced and natural shrubland are not obvious at a catchment scale; (3 the K values of introduced grassland, natural grassland, introduced shrubland and natural shrubland in the 0–5 cm layer vary from 0.008 to 0.037, 0.031 to 0.046, 0.012 to 0.041 and 0.008 to 0.045 (t·hm2·h/(MJ·mm·hm2, while the values vary from 0.009 to 0.039, 0.032 to 0.046, 0.012 to 0.042 and 0.008 to 0.048 (t·hm2·h/(MJ·mm·hm2 in the 5–20 cm layer. The areas with a mean multiyear precipitation of 370–440 mm are the most important places for vegetation restoration construction management at a regional scale. A comprehensive balance between water conservation and soil conservation is needed and important when selecting the species used to vegetation restoration. This study provides suggestions for ecological restoration and provides a case study for the estimate of soil erodibility in arid and semiarid

  1. Identification of genes involved in the mutualistic colonization of the nematode Heterorhabditis bacteriophora by the bacterium Photorhabdus luminescens.

    LENUS (Irish Health Repository)

    Easom, Catherine A

    2010-01-01

    ABSTRACT: BACKGROUND: Photorhabdus are Gram negative entomopathogenic bacteria that also have a mutualistic association with nematodes from the family Heterorhabditis. An essential part of this symbiosis is the ability of the bacterium to colonize the gut of the freeliving form of the nematode called the infective juvenile (IJ). Although the colonization process (also called transmission) has been described phenomonologically very little is known about the underlying molecular mechanisms. Therefore, in this study, we were interested in identifying genes in Photorhabdus that are important for IJ colonization. RESULTS: In this work we genetically tagged P. luminescens TT01 with gfp and constructed a library containing over 3200 mutants using the suicide vector, pUT-Km2. Using a combination of in vitro symbiosis assays and fluorescent microscopy we screened this library for mutants that were affected in their ability to colonize the IJ i.e. with decreased transmission frequencies. In total 8 mutants were identified with transmission frequencies of <\\/= 30% compared to wild-type. These mutants were mapped to 6 different genetic loci; the pbgPE operon, galE, galU, proQ, asmA and hdfR. The pbgPE, galE and galU mutants were all predicted to be involved in LPS biosynthesis and, in support of this, we have shown that these mutants are avirulent and sensitive to the cationic antimicriobial peptide, polymyxin B. On the other hand the proQ, asmA and hdfR mutants were not affected in virulence and were either as resistant (proQ) or slightly more sensitive (asmA, hdfR) to polymyxin B than the wild-type (WT). CONCLUSIONS: This is the first report describing the outcome of a comprehensive screen looking for transmission mutants in Photorhabdus. In total 6 genetic loci were identified and we present evidence that all of these loci are involved in the assembly and\\/or maintenance of LPS and other factors associated with the cell surface. Interestingly several, but not all, of the

  2. Fluvial organic carbon flux from an eroding peatland catchment, southern Pennines, UK

    Directory of Open Access Journals (Sweden)

    R. R. Pawson

    2008-03-01

    Full Text Available This study investigates for the first time the relative importance of dissolved organic carbon (DOC and particulate organic carbon (POC in the fluvial carbon flux from an actively eroding peatland catchment in the southern Pennines, UK. Event scale variability in DOC and POC was examined and the annual flux of fluvial organic carbon was estimated for the catchment. At the event scale, both DOC and POC were found to increase with discharge, with event based POC export accounting for 95% of flux in only 8% of the time. On an annual cycle, exports of 35.14 t organic carbon (OC are estimated from the catchment, which represents an areal value of 92.47 g C m−2 a−1. POC was the most significant form of organic carbon export, accounting for 80% of the estimated flux. This suggests that more research is required on both the fate of POC and the rates of POC export in eroding peatland catchments.

  3. Predictive model for local scour downstream of hydrokinetic turbines in erodible channels

    Science.gov (United States)

    Musa, Mirko; Heisel, Michael; Guala, Michele

    2018-02-01

    A modeling framework is derived to predict the scour induced by marine hydrokinetic turbines installed on fluvial or tidal erodible bed surfaces. Following recent advances in bridge scour formulation, the phenomenological theory of turbulence is applied to describe the flow structures that dictate the equilibrium scour depth condition at the turbine base. Using scaling arguments, we link the turbine operating conditions to the flow structures and scour depth through the drag force exerted by the device on the flow. The resulting theoretical model predicts scour depth using dimensionless parameters and considers two potential scenarios depending on the proximity of the turbine rotor to the erodible bed. The model is validated at the laboratory scale with experimental data comprising the two sediment mobility regimes (clear water and live bed), different turbine configurations, hydraulic settings, bed material compositions, and migrating bedform types. The present work provides future developers of flow energy conversion technologies with a physics-based predictive formula for local scour depth beneficial to feasibility studies and anchoring system design. A potential prototype-scale deployment in a large sandy river is also considered with our model to quantify how the expected scour depth varies as a function of the flow discharge and rotor diameter.

  4. Sub ablative Er: YAG laser irradiation on surface roughness of eroded dental enamel.

    Science.gov (United States)

    Curylofo-Zotti, Fabiana Almeida; Lepri, Taísa Penazzo; Colucci, Vivian; Turssi, Cecília Pedroso; Corona, Silmara Aparecida Milori

    2015-11-01

    This study evaluated the effects of Er:YAG laser irradiation applied at varying pulse repetition rate on the surface roughness of eroded enamel. Bovine enamel slabs (n = 10) were embedded in polyester resin, ground, and polished. To erosive challenges, specimens were immersed two times per day in 20mL of concentrated orange juice (pH = 3.84) under agitation, during a two-day period. Specimens were randomly assigned to irradiation with the Er:YAG laser (focused mode, pulse energy of 60 mJ and energy density of 3.79 J/cm(2) ) operating at 1, 2, 3, or 4 Hz. The control group was left nonirradiated. Surface roughness measurements were recorded post erosion-like formation and further erosive episodes by a profilometer and observed through atomic force microscopy (AFM). Analysis of variance revealed that the control group showed the lowest surface roughness, while laser-irradiated substrates did not differ from each other following post erosion-like lesion formation. According to analysis of covariance, at further erosive episodes, the control group demonstrated lower surface roughness (P > 0.05), than any of the irradiated groups (P enamel eroded. The AFM images showed that the specimens irradiated by the Er:YAG laser at 1 Hz presented a less rough surface than those irradiated at 2, 3, and 4 Hz. © 2015 Wiley Periodicals, Inc.

  5. A PEDOTRANSFER FUNCTION FOR ESTIMATING THE SOIL ERODIBILITY FACTOR IN SICILY

    Directory of Open Access Journals (Sweden)

    Vincenzo Bagarello

    2009-09-01

    Full Text Available The soil erodibility factor, K, of the Universal Soil Loss Equation (USLE is a simple descriptor of the soil susceptibility to rill and interrill erosion. The original procedure for determining K needs a knowledge of soil particle size distribution (PSD, soil organic matter, OM, content, and soil structure and permeability characteristics. However, OM data are often missing and soil structure and permeability are not easily evaluated in regional analyses. The objective of this investigation was to develop a pedotransfer function (PTF for estimating the K factor of the USLE in Sicily (south Italy using only soil textural data. The nomograph soil erodibility factor and its associated first approximation, K’, were determined at 471 sampling points distributed throughout the island of Sicily. Two existing relationships for estimating K on the basis of the measured geometric mean particle diameter were initially tested. Then, two alternative PTFs for estimating K’ and K, respectively, on the basis of the measured PSD were derived. Testing analysis showed that the K estimate by the proposed PTF (eq.11, which was characterized by a Nash-Suttcliffe efficiency index, NSEI, varying between 0.68 and 0.76, depending on the considered data set, was appreciably more accurate than the one obtained by other existing equations, yielding NSEI values varying between 0.21 and 0.32.

  6. Geomorphology and forest management in New Zealand's erodible steeplands: An overview

    Science.gov (United States)

    Phillips, Chris; Marden, Michael; Basher, Les R.

    2018-04-01

    In this paper we outline how geomorphological understanding has underpinned forest management in New Zealand's erodible steeplands, where it contributes to current forest management, and suggest where it will be of value in the future. We focus on the highly erodible soft-rock hill country of the East Coast region of North Island, but cover other parts of New Zealand where appropriate. We conclude that forestry will continue to make a significant contribution to New Zealand's economy, but several issues need to be addressed. The most pressing concerns are the incidence of post-harvest, storm-initiated landslides and debris flows arising from steepland forests following timber harvesting. There are three areas where geomorphological information and understanding are required to support the forest industry - development of an improved national erosion susceptibility classification to support a new national standard for plantation forestry; terrain analysis to support improved hazard and risk assessment at detailed operational scales; and understanding of post-harvest shallow landslide-debris flows, including their prediction and management.

  7. Granular flows on erodible layers: type and evolution of flow and deposit structures

    Science.gov (United States)

    Crosta, G.; De Blasio, F.; De Caro, M.; Volpi, G.; Frattini, P.

    2012-04-01

    The interaction of a fast moving landslide mass with the basal layer over which movement takes place has been discussed in previous contributions. Nevertheless, the evolution of the structures within the moving mass and the erodible layer are still to be described in detail (Hungr and Evans, 2004; Crosta et al., 1992, 2006, 2009, 2011; Dufresne et al., 2010; Mangeney et al., 2010) and modeling results (Crosta et al., 2006, 2009, 2011; Mangeney et al., 2010). We present some of the results from a campaign of laboratory experiments aimed at studying the evolution of a granular flow at the impact with and during the successive spreading over a cohesionless erodible layer. We performed these test to study the processes and to collect data and evidences to compare them with the results of numerical simulations and to verify capabilities of numerical codes. The laboratory setup consists of an inclined slope and an horizontal sector where release and transport, and deposition take place, respectively. Materials used for the tests are: a uniform rounded siliceous sand (Hostun sand; 0.125-0.5 mm) commonly adopted in lab tests because free of scale effects, and a gravel made of angular elements (12 mm in ave. size). Both the materials have been tested in dry conditions. Different slope angles have been tested (40, 45, 50, 55, 50, 66°) as well as different thicknesses of the erodible layer (0, 0.5, 1, 2 cm) and volumes of the released material (1.5, 3, 5, 9.6 liters). Tests have been monitored by means of a high speed camera and the pre- and post-failure geometries have been surveyed by means of a laser scanner. Deposit description allowed also the computation of volumes and the characterization of the different structures developed and frozen into the deposit. Experiments allowed us to observe the extreme processes occurring during the movement and the mise en place of the deposits. In particular, we observe the formation of a clear wave-like feature developing during the

  8. An Epichloë festucae homologue of MOB3, a component of the STRIPAK complex, is required for the establishment of a mutualistic symbiotic interaction with Lolium perenne

    Science.gov (United States)

    Green, Kimberly A.; Becker, Yvonne; Fitzsimons, Helen L.

    2016-01-01

    Summary In both Sordaria macrospora and Neurospora crassa, components of the conserved STRIPAK (striatin‐interacting phosphatase and kinase) complex regulate cell–cell fusion, hyphal network development and fruiting body formation. Interestingly, a number of Epichloë festucae genes that are required for hyphal cell–cell fusion, such as noxA, noxR, proA, mpkA and mkkA, are also required for the establishment of a mutualistic symbiotic interaction with Lolium perenne. To determine whether MobC, a homologue of the STRIPAK complex component MOB3 in S. macrospora and N. crassa, is required for E. festucae hyphal fusion and symbiosis, a mobC deletion strain was generated. The ΔmobC mutant showed reduced rates of hyphal cell–cell fusion, formed intrahyphal hyphae and exhibited enhanced conidiation. Plants infected with ΔmobC were severely stunted. Hyphae of ΔmobC showed a proliferative pattern of growth within the leaves of Lolium perenne with increased colonization of the intercellular spaces and vascular bundles. Although hyphae were still able to form expressoria, structures allowing the colonization of the leaf surface, the frequency of formation was significantly reduced. Collectively, these results show that the STRIPAK component MobC is required for the establishment of a mutualistic symbiotic association between E. festucae and L. perenne, and plays an accessory role in the regulation of hyphal cell–cell fusion and expressorium development in E. festucae. PMID:27277141

  9. Determination of interrill soil erodibility coefficient based on Fuzzy and Fuzzy-Genetic Systems

    Directory of Open Access Journals (Sweden)

    Habib Palizvan Zand

    2017-02-01

    Full Text Available Introduction: Although the fuzzy logic science has been used successfully in various sudies of hydrology and soil erosion, but in literature review no article was found about its performance for estimating of interrill erodibility. On the other hand, studies indicate that genetic algorithm techniques can be used in fuzzy models and finding the appropriate membership functions for linguistic variables and fuzzy rules. So this study was conducted to develop the fuzzy and fuzzy–genetics models and investigation of their performance in the estimation of soil interrill erodibility factor (Ki. Materials and Methods: For this reason 36 soil samples with different physical and chemical properties were collected from west of Azerbaijan province . soilsamples were also taken from the Ap or A horizon of each soil profile. The samples were air-dried , sieved and Some soil characteristics such as soil texture, organic matter (OM, cation exchange capacity (CEC, sodium adsorption ratio (SAR, EC and pH were determined by the standard laboratory methods. Aggregates size distributions (ASD were determined by the wet-sieving method and fractal dimension of soil aggregates (Dn was also calculated. In order to determination of soil interrill erodibility, the flume experiment performed by packing soil a depth of 0.09-m in 0.5 × 1.0 m. soil was saturated from the base and adjusted to 9% slope and was subjected to at least 90 min rainfall . Rainfall intensity treatments were 20, 37 and 47 mm h-1. During each rainfall event, runoff was collected manually in different time intervals, being less than 60 s at the beginning, up to 15 min near the end of the test. At the end of the experiment, the volumes of runoff samples and the mass of sediment load at each time interval were measured. Finally interrill erodibility values were calculated using Kinnell (11 Equation. Then by statistical analyses Dn and sand percent of the soils were selected as input variables and Ki as

  10. Physico-chemical properties and fertility status of water eroded soils of Sharkul area of district Mansehra, Pakistan

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    Farmanullah Khan, A. Iqbal

    2011-11-01

    Full Text Available Soil degradation is the major threat to agricultural sustainability because it affects the soil productivity. Present study was conducted in 2008 to evaluate physico-chemical properties and fertility status of some eroded soil series of Sharkul area district Manshera, Hazara division, Khyber Pakhtunkhwa, Pakistan. Six soil series including slightly eroded (Dosera and Girari, moderately eroded (Nakholi and Sharkul and severely eroded (Ahl and Banser were selected. Soil samples were collected from surface (0-15 cm, subsurface (30-45 cm and substrata soil (60-75cm depths and were analyzed for various soil properties. Due to severity of erosion, bulk density increased, while total porosity, saturation percentage and organic matter decreased significantly. AB-DTPA extractable P, K, Fe, Cu, Zn, and Mn concentrations were decreased due to the severity of erosion in surface and sub surface soils, whereas in the substrata soils (60-75 cm depth, the effect of erosion was almost non significant. Sub-surface and sub-strata soils were found deficient in available P ( Zn > Fe > Mn. The physical and chemical properties of eroded soils varied significantly and the increasing severity of erosion resulted in corresponding deterioration of soil quality.

  11. Coupled diffusion of two species in a slab with an eroding boundary

    International Nuclear Information System (INIS)

    Leite, S.B.; Ozisik, M.N.; Verghese, K.

    1981-01-01

    The diffusion of two interchangeable species in a medium with an eroding boundary is analyzed by modeling the problem as the solution of two diffusion equations coupled at the source term for a slab with a moving boundary. Formal solutions are developed for the concentration of the two species as a function of time and position in the slab for arbitrary initial distributions of the diffusing species, arbitrary sources within the medium and boundary conditions of the third kind at the bounding surfaces. It is shown with an illustrative example, that the resulting coupled integral equations for the species can be solved very efficiently by an approach employing both a lower- and upper-bound starting function for the concentrations. (author)

  12. Bond Stability of a Universal Adhesive System to Eroded/Abraded Dentin After Deproteinization.

    Science.gov (United States)

    Augusto, M G; Torres, Crg; Pucci, C R; Schlueter, N; Borges, A B

    Erosive/abrasive challenges can potentially compromise bonding to dentin. Aiming to improve the quality and stability of bonding to this substrate, this study investigated the combined effect of erosion and toothbrush abrasion on the microtensile bond strength (μTBS) stability to dentin using a universal adhesive system in total and self-etching modes, associated or not associated with deproteinization. Bovine dentin specimens were divided into five groups according to the organic matrix condition (n=20): control (C); erosion (E); erosion + abrasion (EA); erosion + sodium hypochlorite (EH); erosion + abrasion + sodium hypochlorite (EAH). The groups were further divided (n=10) according to the mode of application (total or self-etching) of a universal adhesive. After the bonding procedure, composite blocks were built up, and the samples were cut to obtain sticks for μTBS testing. For each specimen, one-half of the sticks was immediately tested, and the other one-half was tested after artificial aging (5000 thermocycles, 5°C and 55°C). Three-way analysis of variance (α=5%) showed a significant difference for the triple interaction ( p=0.0007). Higher μTBS means were obtained for the EH and EAH groups compared with the E and EA groups. The control group showed immediate μTBS values similar to that of the E and EA groups for both bond strategies. Erosion and erosion/abrasion did not significantly influence the immediate μTBS to dentin. Artificial aging reduced μTBS values for the groups C, E, and EA using the total-etching mode. Deproteinization maintained the bond stability to artificially aged eroded and eroded/abraded dentin.

  13. The transient response for different types of erodable surface thermocouples using finite element analysis

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    Mohammed Hussein

    2007-01-01

    Full Text Available The transient response of erodable surface thermocouples has been numerically assessed by using a two dimensional finite element analysis. Four types of base metal erodable surface thermocouples have been examined in this study, included type-K (alumel-chromel, type-E (chromel-constantan, type-T (copper-constantan, and type-J (iron-constantan with 50 mm thick- ness for each. The practical importance of these types of thermocouples is to be used in internal combustion engine studies and aerodynamics experiments. The step heat flux was applied at the surface of the thermocouple model. The heat flux from the measurements of the surface temperature can be commonly identified by assuming that the heat transfer within these devices is one-dimensional. The surface temperature histories at different positions along the thermocouple are presented. The normalized surface temperature histories at the center of the thermocouple for different types at different response time are also depicted. The thermocouple response to different heat flux variations were considered by using a square heat flux with 2 ms width, a sinusoidal surface heat flux variation width 10 ms period and repeated heat flux variation with 2 ms width. The present results demonstrate that the two dimensional transient heat conduction effects have a significant influence on the surface temperature history measurements made with these devices. It was observed that the surface temperature history and the transient response for thermocouple type-E are higher than that for other types due to the thermal properties of this thermocouple. It was concluded that the thermal properties of the surrounding material do have an impact, but the properties of the thermocouple and the insulation materials also make an important contribution to the net response.

  14. Crop Performance and Soil Properties in Two Artificially-Eroded Soils in North-Central Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Izaurralde, R Cesar C.; Malhi, S. S.; Nyborg, M.; Solberg, E. D.; Quiroga Jakas, Maria C.

    2006-09-01

    Field experiments were conducted from 1991 to 1995 at Josephburg (Orthic Black Chernozem, Typic Cryoboroll) and Cooking Lake (Orthic Gray Luvisol, Typic Cryoboralf), Alberta, to determine impact of topsoil removal on selected soil properties, N-mineralization potential and crop yield, and effectiveness of various amendments for restoring the productivity of eroded soils. The simulated-erosion levels were established in the autumn of 1990 by removing 20 cm topsoil in 5-cm depth increments. The four amendments were: control, addition of 5 cm of topsoil, fertilizers to supply 100 kg N ha-1 and 20 kg P ha-1, and cattle manure at 75 Mg ha-1. Topsoil and manure were applied once in the autumn of 1990, while fertilizers were applied annually from 1991 to 1995. Available N and P, total C, N and P, and N-mineralization potential decreased, while bulk density increased with increasing depth of topsoil removal. Tiller number, plant height, spike density, thousand kernel weight, and leaf area index decreased with simulated erosion. Grain yield reductions due to simulated soil erosion were either linear or curvilinear functions of nutrient removal. Application of N and P fertilizers and manure improved grain yield and reduced the impact of yield loss due to erosion. Return of 5 cm of topsoil also increased grain yield, but to a lesser extent than manure or fertilizers. Grain yields were maximized when fertilizers were also applied to organic amendment treatments. In conclusion, the findings suggest the importance of integrated use of organic amendments and chemical fertilizers for best crop yields on severely-eroded soils.

  15. Deposition of eroded soil on terraced croplands in Minchet catchment, Ethiopian Highlands

    Directory of Open Access Journals (Sweden)

    Alemtsehay Subhatu

    2017-09-01

    Full Text Available In the Ethiopian Highlands, soil and water conservation practices are of utmost importance to conserve eroded soil and combat soil loss. This study provides detailed results on on-site sediment deposition and net soil loss in terraced croplands in a catchment in the sub-humid Ethiopian Highlands. Sediment deposition was measured on horse bean and maize fields during the crop growing seasons of 2014 and 2015. Measurements took place on observation plots on terraced cropland with varying spacing between terraces and varying slope gradients. Net soil loss, in this case the amount leaving the terraced cropland, was calculated by modelling the Universal Soil Loss Equation (USLE for the whole observation field and subtracting the measured sediment deposition. The study result showed about 8–11 t ha−1 sediment was deposited in the deposition zone of the terraced cropland, with greater sediment deposition on terraces with narrow spacing and steeper slope gradients. Sediment deposition was highest in July and August, and relatively low in September. Annual soil loss ranged from 32 to 37 t ha−1 in the terraced cropland of the study area. From the total soil loss in the crop growing season, about 54–74% sediment was deposited on the deposition zone of terraced crop fields. Implementation of soil and water conservation with narrow spacing, especially on the steep slopes of the sub-humid Ethiopian Highlands or other similar area, are thus highly recommended as they enable conservation of the eroded soil in the cropland.

  16. Digging deeper - How soil biota drive and respond to plant invasions

    NARCIS (Netherlands)

    Shelby, Natasha; Duncan, Richard P.; Putten, Van Der Wim H.; Mcginn, Kevin J.; Weser, Carolin; Hulme, Philip E.

    2016-01-01

    1. The performance of introduced plants can be limited by the availability of soil mutualists outside their native range, but how interactions with mutualists differ between ranges is largely unknown. If mutualists are absent, incompatible or parasitic, plants may compensate by investing more in

  17. Interrill Erodibility of P and C on conventially and organically farmed Devon soils

    Science.gov (United States)

    Kuhn, N. J.

    2012-04-01

    Soil erosion can have significant off-site effects on water quality and thus human and habitat health. Apart from sedimentation, the transfer of nutrients, both dissolved and particulate, is a major concern. The particulate transfer of nutrients from agricultural land can occur either by rill or interrill erosion. Rill erosion is non-selective and affects only a limited extent of agricultural land. Interrill processes such as crusting, splash and raindrop-impacted wash, on the other hand, act on all cropland and affect the quality of the water from all areas generating runoff. A significant amount of phosphorus (P) is contained in the surface soil layer transformed by interrill processes annually. In the EU, the P content of a crusted (2 mm) surface layer corresponds to 4 to 40 kg ha-1 of P on arable land (1.094 mil km2). Therefore, the role of interrill processes and erosion for regional nutrient cycling requires close attention. Interrill erosion is a complex phenomenon, involving the detachment, transport and deposition of soil particles by raindrop impacted flow. Resistance to interrill erosion varies between soils depending on their physical, chemical and mineralogical properties. In addition, significant changes in soil resistance to interrill erosion occur during storms as a result of changes in surface roughness, cohesion and particle size. As a consequence, erosion on interrill areas is selective, moving the most easily detached small and/or light soil particles which are often enriched in clay, P and organic C. Commonly, the risk of erosion associated with organically farmed soils is lower than those farmed in a conventional way. This is attributed to greater aggregate stability and thus greater infiltration and lower erodibility. Erosion of nutrients on organically farmed soils is therefore considered to be reduced by the same order of magnitude than the amount of eroded soil compared to conventionally farmed soils. However, the selective nature of

  18. Sensitivity Analysis of the USLE Soil Erodibility Factor to Its Determining Parameters

    Science.gov (United States)

    Mitova, Milena; Rousseva, Svetla

    2014-05-01

    Soil erosion is recognized as one of the most serious soil threats worldwide. Soil erosion prediction is the first step in soil conservation planning. The Universal Soil Loss Equation (USLE) is one of the most widely used models for soil erosion predictions. One of the five USLE predictors is the soil erodibility factor (K-factor), which evaluates the impact of soil characteristics on soil erosion rates. Soil erodibility nomograph defines K-factor depending on soil characteristics, such as: particle size distribution (fractions finer that 0.002 mm and from 0.1 to 0.002 mm), organic matter content, soil structure and soil profile water permeability. Identifying the soil characteristics, which mostly influence the K-factor would give an opportunity to control the soil loss through erosion by controlling the parameters, which reduce the K-factor value. The aim of the report is to present the results of analysis of the relative weight of these soil characteristics in the K-factor values. The relative impact of the soil characteristics on K-factor was studied through a series of statistical analyses of data from the geographic database for soil erosion risk assessments in Bulgaria. Degree of correlation between K-factor values and the parameters that determine it was studied by correlation analysis. The sensitivity of the K-factor was determined by studying the variance of each parameter within the range between minimum and maximum possible values considering average value of the other factors. Normalizing transformation of data sets was applied because of the different dimensions and the orders of variation of the values of the various parameters. The results show that the content of particles finer than 0.002 mm has the most significant relative impact on the soil erodibility, followed by the content of particles with size from 0.1 mm to 0.002 mm, the class of the water permeability of the soil profile, the content of organic matter and the aggregation class. The

  19. Soil aggregates, organic matter turnover and carbon balance in a Mediterranean eroded vineyard

    Science.gov (United States)

    Novara, Agata; Lo Papa, Giuseppe; Dazzi, Carmelo; Gristina, Luciano; Cerdà, Artemi

    2014-05-01

    The carbon cycle is being affected by the human impacts (Novara et al., 2011; Yan-Gui et al., 2013), and one of those is the intensification in the soil erosion in agriculture land (Cerdà et al., 2009; García Orenes et al., 2009). Vineyards also are affected by the human activities (Fernández Calviño, 2012). Vineyards in Sicily are cultivated on 110.000 ha, 10% of which on >10% slope. Deficiencies of soil organic matter are typical of the semi arid Mediterranean environment especially where traditional intensive cropping practices are adopted (Novara et al., 2012; 2013). These practices in vineyards could lead soil to intensive erosion processes (Novara et al., 2011). The fate of SOC under erosion processes is difficult to understand because of the influence of the erosion impact on SOC pathway, which depends on the different features of the process involved (detachment, transport and/or deposition). Soil erosion must be considered a net C source (Lal, 2003), as eroded soils have lower net primary productivity (NPP) (Dick and Gregorich, 2004) caused by reduction in the effective rooting depth and all in all determining decline in soil quality. Breakdown of aggregates and soil dispersion expose SOM to microbial/enzymatic processes and chemical soil properties (Dimoyiannis, 2012; Kocyigit and Demirci, 2012). Moreover the light fraction, transported by runoff, is labile and easily mineralized determining CO2 emission in the atmosphere (Jacinthe and Lal, 2004). Therefore, the carbon pool is lower in eroded than in un-eroded soil scapes and the rate of mineralization of soil organic matter is higher in sediments than in original soil. In this survey we show a research conducted on a slope sequence of three soil profiles in an irrigated vineyard located in Sambuca di Sicilia, Italy (UTM33-WGS84: 4169367N; 325011E). The SOC content was measured at depth intervals of 10 cm up to a depth of 60 cm in each pedon. Wet aggregate-size fractions with no prior chemical

  20. Mulching as a strategy to improve soil properties and reduce soil erodibility in coffee farming systems of Rwanda

    NARCIS (Netherlands)

    Nzeyimana, I.; Hartemink, A.E.; Ritsema, C.J.; Stroosnijder, L.; Huerta Lwanga, Esperanza; Geissen, V.

    2017-01-01

    In Rwanda, mulch is applied in coffee fields to control soil erosion. The objective of this paper is to quantify the effects of different types of mulch on soil properties and soil erodibility in coffee farming systems in three different agro-ecological zones of the highlands of Rwanda. The

  1. Tracing the source of soil organic matter eroded from temperate forest catchments using carbon and nitrogen isotopes

    Science.gov (United States)

    Emma P. McCorkle; Asmeret Asefaw Berhe; Carolyn T. Hunsaker; Dale W. Johnson; Karis J. McFarlane; Marilyn L. Fogel; Stephen C. Hart

    2016-01-01

    Soil erosion continuously redistributes soil and associated soil organic matter (SOM) on the Earth's surface, with important implications for biogeochemical cycling of essential elements and terrestrial carbon sequestration. Despite the importance of soil erosion, surprisingly few studies have evaluated the sources of eroded carbon (C). We used natural abundance...

  2. The impacts of grazing land management on the wind erodibility of the Mulga Lands of western Queensland, Australia

    Science.gov (United States)

    An estimated 100 Mt of dust is eroded by wind from the Australian land surface each year. Wind erosion may be widespread across the arid and semi-arid rangelands, with impacts on soil nutrients, carbon and ecosystem services, human health, and climate. The susceptibility of landscapes to wind erosio...

  3. Restoring crop productivity of eroded lands through , integrated plant nutrient management (IPNM) for sustained production

    International Nuclear Information System (INIS)

    Bhatti, A.U.; Ali, S.

    2005-01-01

    Crop productivity of eroded lands is very poor due to removal of top fertile soil losing organic matter and plant nutrients, with consequent exposure of the sub-soil with poor fertility status. Crop productivity of such lands needs to be restored in order to help farmers feed many mouths because of increased population and high land pressure. Three field experiments were laid out at three sites, Thana, Malakand Agency; Kabal and Matta, Swat during 2003-2004 to study the effect of integrated plant nutrient management on the yield of wheat. The fertilizer treatments consisted of farmer's practice (60-45-0 kg N-P/sub 2/O/sub 5/-K/sub 2/O ha/sup -1/), recommended fertilizer rate (120-90-60 kg N-P/sub 2/O/sub 5/-K/sub 2/O ha/sup -l/ + 5 kg Zn ha/sup -1), and combined application of organic and inorganic sources of plant nutrients (FYM at the rate of 20 t ha/sup -1/ plus 60-90-60 kg N-P/sub 2/O/sub 5/-K/sub 2/O ha/sup -1/ + 5 kg Zn ha/sup -1/). The results obtained from these field trails showed that the combined application of FYM with NPK Zn increased the grain yield significantly over the other two treatments with an increase of 50-80% over the farmer's practice and 11 to 23 % over the recommended dose. As regards straw yields, T/sub 2/ and T/sub 3/ increased the yields significantly over farmer's practice (T) at all the sites; However, T/sub 2/ and T/sub 3/ at Thana and Kabal were at par with each other. As regards effect of various treatments on soil properties, organic matter content was improved at Thana and Kabal sites while at Matta the results were inconsistent. Similarly soil P and Zn contents were increased considerably in T/sub 2/ and T/sub 3/ at Thana and Kabal being at par with each other. It is apparent from these results that the crop productivity of eroded lands at all the three sties was considerably restored and the soil fertility status was improved by integrated plant nutrient management. (author)

  4. Erodibility of calcareous soils as influenced by land use and intrinsic soil properties in a semiarid region of central Iran.

    Science.gov (United States)

    Ayoubi, Shamsollah; Mokhtari, Javad; Mosaddeghi, Mohammad Reza; Zeraatpisheh, Mojtaba

    2018-03-06

    The most important properties affecting the soil loss and runoff were investigated, and the effects of land use on the soil properties, together with the erodibility indices in a semiarid zone, central Iran, were evaluated. The locations of 100 positions were acquired by cLHS and 0-5-cm surface soil layer samples were used for laboratory analyses from the Borujen Region, Chaharmahal-Va-Bakhtiari Province, central Iran. To measure in situ runoff and soil erodibility of three different land uses comprising dryland, irrigated farming, and rangeland, a portable rainfall simulator was used. The results showed that the high variations (coefficient of variation, CV) were obtained for electrical conductivity (EC), mean weight diameter (MWD), soil organic carbon (SOC), and soil erodibility indices including runoff volume, soil loss, and sediment concentration (CV ~ 43.6-77.4%). Soil erodibility indices showed positive and significant correlations with bulk density and negative correlations with SOC, MWD, clay content, and soil shear strength in the area under investigation. The values of runoff in the dryland, irrigated farming, and rangeland were found 1.5, 28.9, and 58.7 cm 3 ; soil loss in the dryland, irrigated farming, and rangeland were observed 0.25, 2.96, and 76.8 g; and the amount of sediment concentration in the dryland, irrigated farming, and rangeland were found 0.01, 0.11, and 0.15 g cm -3 . It is suggested that further investigations should be carried out on soil erodibility and the potential of sediment yield in various land uses with varying topography and soil properties in semiarid regions of Iran facing the high risk of soil loss.

  5. Numerical Investigation of Temperature Distribution in an Eroded Bend Pipe and Prediction of Erosion Reduced Thickness

    Science.gov (United States)

    Zhu, Hongjun; Feng, Guang; Wang, Qijun

    2014-01-01

    Accurate prediction of erosion thickness is essential for pipe engineering. The objective of the present paper is to study the temperature distribution in an eroded bend pipe and find a new method to predict the erosion reduced thickness. Computational fluid dynamic (CFD) simulations with FLUENT software are carried out to investigate the temperature field. And effects of oil inlet rate, oil inlet temperature, and erosion reduced thickness are examined. The presence of erosion pit brings about the obvious fluctuation of temperature drop along the extrados of bend. And the minimum temperature drop presents at the most severe erosion point. Small inlet temperature or large inlet velocity can lead to small temperature drop, while shallow erosion pit causes great temperature drop. The dimensionless minimum temperature drop is analyzed and the fitting formula is obtained. Using the formula we can calculate the erosion reduced thickness, which is only needed to monitor the outer surface temperature of bend pipe. This new method can provide useful guidance for pipeline monitoring and replacement. PMID:24719576

  6. Evaluation of the WEPP hillslope model on stable and eroding semiarid woodlands

    International Nuclear Information System (INIS)

    Wilcox, B.P.; Simanton, J.R.

    1995-01-01

    In this paper, we evaluate runoff and erosion prediction by the WEPP hillslope model for two pinyon-juniper sites in New Mexico: one has a low erosion rate (stable site) and the other (unstable site) is eroding at very rapid rates (as a result of landuse and climatic perturbations over the last century). Runoff and erosion measurements were made at plot and hillslope scales at both sites. WEPP was evaluated using both rainfall simulation and natural rainfall data. Rainfall simulation was performed on both vegetated and bare plots. Parameter values used were developed from rainfall simulation experiments and site characteristics. In general, runoff and erosion were underpredicted at both sites but to a much larger degree at the unstable site. On the unstable site predictions were much improved when we used hydraulic conductivity (Ke) derived from the bare plot rainfall simulation. Also of importance, at the unstable site we observed a large increase in erosion as scale increased from the plot to the hillslope as a result of a well developed channel network. These results are preliminary, in that only a few storms were evaluated, however, they do suggest some important strategies for predicting the impact of reduced vegetation cover to erosion in semiarid landscapes

  7. Tritium recycling and inventory in eroded debris of plasma-facing materials

    International Nuclear Information System (INIS)

    Hassanein, A.

    1999-01-01

    Damage to plasma-facing components (PFCs) and structural materials due to loss of plasma confinement in magnetic fusion reactors remains one of the most serious concerns for safe, successful, and reliable tokamak operation. High erosion losses due to surface vaporization, spallation, and melt-layer splashing are expected during such an event. The eroded debris and dust of the PFCs, including trapped tritium, will be contained on the walls or within the reactor chamber therefore, they can significantly influence plasma behavior and tritium inventory during subsequent operations. Tritium containment and behavior in PFCS and in the dust and debris is an important factor in evaluating and choosing the ideal plasma-facing materials (PFMs). Tritium buildup and release in the debris of candidate materials is influenced by the effect of material porosity on diffusion and retention processes. These processes have strong nonlinear behavior due to temperature, volubility, and existing trap sites. A realistic model must therefore account for the nonlinear and multidimensional effects of tritium diffusion in the porous-redeposited and neutron-irradiated materials. A tritium-transport computer model, TRAPS (Tritium Accumulation in Porous Structure), was developed and used to evaluate and predict the kinetics of tritium transport in porous media. This model is coupled with the TRICS (Tritium In Compound Systems) code that was developed to study the effect of surface erosion during normal and abnormal operations on tritium behavior in PFCS

  8. Workplace bullying erodes job and personal resources: between- and within-person perspectives.

    Science.gov (United States)

    Tuckey, Michelle R; Neall, Annabelle M

    2014-10-01

    Workplace bullying is a serious psychosocial occupational hazard. Despite a wealth of empirical study, research has rarely examined the mechanisms through which bullying has its negative effects. Accordingly, using both between- and within-person approaches, we investigated the erosion of job (Study 1) and personal (Study 2) resources following workplace bullying, mediated by the depletion of emotional energy. In Study 1, self-report survey data were collected from 221 retail workers at 2 time-points spaced 6 months apart. Structural equation modeling revealed that over time bullying depletes coworker support, partially mediated by emotional exhaustion. In Study 2, a 6-week diary was completed by a separate sample of 45 workers employed in various occupations. Within-person weekly variability in bullying exposure was 34%. Hierarchical linear modeling showed that weekly emotional exhaustion partially mediated the negative effects of weekly workplace bullying on both optimism and self-efficacy. The consistent pattern across both studies supports the idea of a resource loss process whereby exposure to bullying at work erodes job and personal resources by depleting energy. Future research should clarify the role of exhaustion in utilizing resources to respond to bullying, focus on predictors of within-person variability in bullying exposure, and more explicitly model the resource loss spiral following workplace bullying. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

  9. SOIL ERODIBILITY IN THE BRAZILIAN COASTAL PLAINS ERODIBILIDADE DO SOLO NOS TABULEIROS COSTEIROS

    Directory of Open Access Journals (Sweden)

    Nilton Curi

    2011-07-01

    Full Text Available

    In order to determine soil losses caused by water erosion, in different situations, erosion prediction models, such as the Universal Soil Loss Equation (USLE, are used. Their application on agricultural and environmental planning depends on the determination of the USLE factors, including erodibility (K factor. The objective of this study was to determine erodibility for the main soil classes of the Brazilian Coastal Plains region, in Aracruz, Espírito Santo State. The experiment was established in the following soils: medium/clayey texture Yellow Argisol (PA1, Haplic Plinthosol (FX, and moderately rocky Yellow Argisol (PA2. For the calculation of soil erodibility, data of erosivity and soil losses, from November 1997 to May 2004, were used. Soil losses samplings were performed for each rainfall event regarded as erosive. The erodibility values were 0.007 Mg h MJ-1 mm-1

  10. Social perception of soil conservation benefits in Kondoa eroded area of Tanzania

    Directory of Open Access Journals (Sweden)

    Rajendra P. Shrestha

    2015-09-01

    Full Text Available A soil conservation project was implemented in Tanzania for over 30 years. This study applied a socio-economic approach to examine and analyse the benefits of soil conservation in the Kondoa eroded area of Tanzania by conducting a household survey of 240 households. The study findings show that 89% and 70% of respondents consider soil conservation activities have increased vegetation and soil fertility, respectively. Decreased soil erosion was perceived by 68% of respondents, increased firewood by 98%, increased fodder by 50%, high crop yields by 56%, and food sufficiency by 68%. These are the outcomes of conservation tillage, integrated farming and use of organic fertilizers, controlled stall feeding, agroforestry, construction of cut off drains, contour bunds and contour ridges cultivation, which are the main land use practices in the area. Access to extension services, household sizes, long term land ownership, crop incomes and awareness of soil conservation project were found to determine the level of participation in soil conservation. Major challenges are the lack of sustainability of those activities because of a recent policy decision to withdraw conservation investment. Despite the challenge, this study concluded that past government efforts on soil conservation activities initiated since the early 1970s through decentralization, institutional collaboration, socioeconomic support to farmers and continuous local community participation in restoring the degraded ecosystem of Kondoa have contributed to ensure environmental and socio-economic sustainability in the area.

  11. Erodibility of cement-stabilized tropical soils in highway engineering in Togo

    International Nuclear Information System (INIS)

    Eklu-Natey, T.E.D.

    1992-01-01

    This work contains a methodical study on the suceptibility to weather of cement-stabilized tropical soils of Togo by simulating on the one hand the climatic conditions of the original surroundings and on the other hand the variations occuring in situ of the degree of saturation and compaction. The chosen tests ensure for the first time a simple execution and at the same time reproducible numerical values of the results achieved. From results of the slaking, erosion, adhesion, durability and swelling tests clear parameters and classification criteria were derived which help to forecast the susceptibility to weather of soils in tropical climates. A method for the determination of the reaction to water of soils is proposed consisting of a particular process of derivation and interpretation of the consistency value for a given swelling rate. Moreover a possibility is recommended with which the time-consuming and expensive mineralogical analyses which were frequently used in the past for torpical soils can be avoided. The proposed evaluation criteria provides civil engineers working in permanently moist, arid or intermittently moist tropical regions with practical and theoretical bases for the estimation of the erodibility of soils. (orig./BBR) [de

  12. Microbial oxidation of lithospheric organic carbon in rapidly eroding tropical mountain soils.

    Science.gov (United States)

    Hemingway, Jordon D; Hilton, Robert G; Hovius, Niels; Eglinton, Timothy I; Haghipour, Negar; Wacker, Lukas; Chen, Meng-Chiang; Galy, Valier V

    2018-04-13

    Lithospheric organic carbon ("petrogenic"; OC petro ) is oxidized during exhumation and subsequent erosion of mountain ranges. This process is a considerable source of carbon dioxide (CO 2 ) to the atmosphere over geologic time scales, but the mechanisms that govern oxidation rates in mountain landscapes are poorly constrained. We demonstrate that, on average, 67 ± 11% of the OC petro initially present in bedrock exhumed from the tropical, rapidly eroding Central Range of Taiwan is oxidized in soils, leading to CO 2 emissions of 6.1 to 18.6 metric tons of carbon per square kilometer per year. The molecular and isotopic evolution of bulk OC and lipid biomarkers during soil formation reveals that OC petro remineralization is microbially mediated. Rapid oxidation in mountain soils drives CO 2 emission fluxes that increase with erosion rate, thereby counteracting CO 2 drawdown by silicate weathering and biospheric OC burial. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  13. Local and non-local effects of spanwise finite perturbations in erodible river bathymetries

    Science.gov (United States)

    Musa, Mirko; Hill, Craig; Guala, Michele

    2015-11-01

    Laboratory experiments were performed to study the effect of axial-flow hydrokinetic turbine models on an erodible river bed under live-bed conditions. Results indicate that the presence of an operating turbine rotor creates a blockage in the mean flow which produces a remarkable geomorphic signature in the migrating bedforms. These impacts affect a local area downstream of the turbines when placed symmetrically with respect to the cross section of the channel. On the other hand, more interesting results are observed with an asymmetric installation of the turbines. This configuration demonstrates a stronger effect on the mean flow, resulting in a larger plan-wise distortion of the mean topography and differential migration patterns of bedforms. Different turbine installation arrangements and hub heights above the mean bed were investigated, focusing mainly on the perturbation of sediment transport characteristics influenced by the turbine wake. Additional results with spanwise modulated submerged walls explore the possibility to control river topography harvesting this type of geomorphic destabilization.

  14. Bond strength and interfacial morphology of orthodontic brackets bonded to eroded enamel treated with calcium silicate-sodium phosphate salts or resin infiltration.

    Science.gov (United States)

    Costenoble, Aline; Vennat, Elsa; Attal, Jean-Pierre; Dursun, Elisabeth

    2016-11-01

     To investigate the shear bond strength (SBS) of orthodontic brackets bonded to eroded enamel treated with preventive approaches and to examine the enamel/bracket interfaces.  Ninety-one brackets were bonded to seven groups of enamel samples: sound; eroded; eroded+treated with calcium silicate-sodium phosphate salts (CSP); eroded+infiltrated by ICON ® ; eroded+infiltrated by ICON ® and brackets bonded with 1-month delay; eroded+infiltrated by an experimental resin; and eroded+infiltrated by an experimental resin and brackets bonded with 1-month delay. For each group, 12 samples were tested in SBS and bond failure was assessed with the adhesive remnant index (ARI); one sample was examined using scanning electron microscopy (SEM).  Samples treated with CSP or infiltration showed no significant differences in SBS values with sound samples. Infiltrated samples followed by a delayed bonding showed lower SBS values. All of the values remained acceptable. The ARI scores were significantly higher for sound enamel, eroded, and treated with CSP groups than for all infiltrated samples. SEM examinations corroborated the findings.  Using CSP or resin infiltration before orthodontic bonding does not jeopardize the bonding quality. The orthodontic bonding should be performed shortly after the resin infiltration.

  15. ASSESSMENT SPATIAL VARIABILITY OF SOIL ERODIBILITY BY USING OF GEOSTATISTIC AND GIS (Case study MEHR watershed of SABZEVAR

    Directory of Open Access Journals (Sweden)

    Ayoubi, S.A

    2005-05-01

    Full Text Available Soil erodibility is one of the key factors on some sediment and soil erosion models such as USLE, MUSLE, RUSLE, AUSLE (USLE modified in LS factor and MMF and represents like K factor and is function of particle distribution, organic mater, soil structure and ermeability. Traditional methods do not take spatial variability and estimate precision of variables in to consideration and amount of them are constant across the whole of soil series .This study was performed to assess spatial variability of soil erodibility and its relevant variables at MEHR watershed from Khorasan province, in northern Iran. Interested network was designed by 110 samples like nested- systematic with distance about 50, 100, 250 and 500 meter across the study area by preparing point map at GIS. Sampling points were identified in field by an Global Positioning system. Soil sampling was done at depth of 0-5cm of ground surface and permeability was studied at depth of 5-30 cm. Some soil properties such as particle distribution and organic mater were measured at laboratory. Particle size distribution was determined by Hydrometer method and Organic matter was measured by wet oxidation approach. Then spatial analysis was done. Variography analysis on soil attributes according to soil erodibility, showed that Gaussian, exponential and spherical models were the most models to predict spatial variability of soil parameters. The range of spatial dependencies was changed from 320 to 3200 m. Soil attribute maps prepared by kriging technique using models parameters. Then soil attributes were composed by Wischmeier (1978 formula in Illwis media to calculate K factor. Amount of soil erodibility changed from 0.13 to 0.91 that it's maximum and minimum was identified in east and southwest of studiedarea. Soil spatial variability pattern, is similar to silt pattern due to high effect of silt on soil rodibility, Also that is partially confirmed with geology map, indicated which soil

  16. Molecular weight-dependent degradation and drug release of surface-eroding poly(ethylene carbonate).

    Science.gov (United States)

    Bohr, Adam; Wang, Yingya; Harmankaya, Necati; Water, Jorrit J; Baldursdottír, Stefania; Almdal, Kristoffer; Beck-Broichsitter, Moritz

    2017-06-01

    Poly(ethylene carbonate) (PEC) is a unique biomaterial showing significant potential for controlled drug delivery applications. The current study investigated the impact of the molecular weight on the biological performance of drug-loaded PEC films. Following the preparation and thorough physicochemical characterization of diverse PEC (molecular weights: 85, 110, 133, 174 and 196kDa), the degradation and drug release behavior of rifampicin- and bovine serum albumin-loaded PEC films was investigated in vitro (in the presence and absence of cholesterol esterase), in cell culture (RAW264.7 macrophages) and in vivo (subcutaneous implantation in rats). All investigated samples degraded by means of surface erosion (mass loss, but constant molecular weight), which was accompanied by a predictable, erosion-controlled drug release pattern. Accordingly, the obtained in vitro degradation half-lives correlated well with the observed in vitro half-times of drug delivery (R 2 =0.96). Here, the PEC of the highest molecular weight resulted in the fastest degradation/drug release. When incubated with macrophages or implanted in animals, the degradation rate of PEC films superimposed the results of in vitro incubations with cholesterol esterase. Interestingly, SEM analysis indicated a distinct surface erosion process for enzyme-, macrophage- and in vivo-treated polymer films in a molecular weight-dependent manner. Overall, the molecular weight of surface-eroding PEC was identified as an essential parameter to control the spatial and temporal on-demand degradation and drug release from the employed delivery system. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Wind-Eroded Crater Floors and Intercrater Plains, Terra Sabaea, Mars

    Science.gov (United States)

    Irwin, Rossman P.; Wray, James J.; Mest, Scott C.; Maxwell, Ted A.

    2018-02-01

    Ancient impact craters with wind-eroded layering on their floors provide a record of resurfacing materials and processes on early Mars. In a 54 km Noachian crater in Terra Sabaea (20.2°S, 42.6°E), eolian deflation of a friable, dark-toned layer up to tens of meters thick has exposed more resistant, underlying light-toned material. These layers differ significantly from strata of similar tone described in other regions of Mars. The light-toned material has no apparent internal stratification, and visible/near-infrared spectral analysis suggests that it is rich in feldspar. Its origin is ambiguous, as we cannot confidently reject igneous, pyroclastic, or clastic alternatives. The overlying dark-toned layer is probably a basaltic siltstone or sandstone that was emplaced mostly by wind, although its weak cementation and inverted fluvial paleochannels indicate some modification by water. Negative-relief channels are not found on the crater floor, and fluvial erosion is otherwise weakly expressed in the study area. Small impacts onto this crater's floor have exposed deeper friable materials that appear to contain goethite. Bedrock outcrops on the crater walls are phyllosilicate bearing. The intercrater plains contain remnants of a post-Noachian thin, widespread, likely eolian mantle with an indurated surface. Plains near Hellas-concentric escarpments to the north are more consistent with volcanic resurfacing. A 48 km crater nearby contains similar dark-over-light outcrops but no paleochannels. Our findings indicate that dark-over-light stratigraphy has diverse origins across Mars and that some dark-toned plains with mafic mineralogy are not of igneous origin.

  18. Temporal shift of sea turtle nest sites in an eroding barrier island beach

    Science.gov (United States)

    Fujisaki, Ikuko; Lamont, Margaret M.; Carthy, Raymond R.

    2018-01-01

    Shoreline changes affect functionality of a sandy beach as a wildlife habitat and coastal erosion is among the primary causes of the changes. We examined temporal shifts in locations where loggerheads placed nests in relation to coastal erosion along a barrier island beach in the northern Gulf of Mexico. We first confirmed consistency in long-term (1855–2001), short-term (1976–2001), and more recent (2002–2012) shoreline change rates in two adjacent beach sections, one historically eroding (west beach) and the other accreting (east beach). The mean annual shoreline change rate in the two sections was significantly different in all time periods. The recent (1998–2012) mean change rate was −10.9 ± 9.9 m/year in the west beach and −2.8 ± 4.9 m/year in the east beach, which resulted in the loss of about 70% and 30% of area in the west and east beaches, respectively. Loggerheads nested significantly closer to the vegetation line in 2012 than in 2002 in the west beach but the difference between the two time periods was not significant in the east beach. However, the distance from nests to the vegetation line from 2002 to 2014 was significantly reduced annually in both beaches; on average, loggerheads nested closer to the vegetation line by 9 m/year in the west beach and 5.8 m/year in the east beach. The observed shoreline change rate and corresponding shift of nest placement sites, combined with the forecasted future beach loss, highlighted the importance of addressing the issue of beach erosion to conserve sandy beach habitats.

  19. Ethoxyresorufin-O-deethylase (EROD) induction in rainbow trout exposed to diluted oil sand wastewater

    International Nuclear Information System (INIS)

    Verbeek, A.; Mackay, W.; Birkholz, D.

    1995-01-01

    Toxic industrial wastewaters, such as those from oil sands extraction, must be assessed for their potential sublethal effects before they can be safely disposed in the environment. The induction of ethoxyresorufin-O-deethylase activity was assessed as a potential bioindicator of sublethal stress in rainbow trout exposed to sublethal concentrations of oil sands tailings water. The mixed-function oxygenase system in rainbow trout responded rapidly following a definable concentration-response relationship; however, it proved to be a relatively insensitive indicator of sublethal exposure to oil sands tailings water. Increased activity and maximal induction, as a result of exposure to 0.3 and 0.6 times the LC 50 (Toxic Units), occurred rapidly within 24 hours of exposure. The linearity of the relationship between the concentration of oil sands tailings pond water and ethoxyresorufin-O-deethylase activity, expressed by the following regression equation, In EROD = 3.68 (conc.) + 3.20, had an r 2 value of 0.593. Maximal induction required 0.4--0.8 Toxic Units. The absolute level of maximal induction was only one-fifth to one-sixth of the potential induction as found in response to the positive control, 0.5 mg/kg β-naphthoflavone (i.p.). The authors also present data that suggests that the different levels of induction observed in trout exposed to tailings pond water vs those injected with 0.5 mg/kg β-naphthoflavone (i.p.) may be indicative of two different P450 isoforms, the CYP4Al isoform responding to the organic acidic surfactants in oil sands tailings pond water and the CYP1A1 isoform, the isoform generally associated with most xenobiotic transformation in fish, responding to β-naphthoflavone

  20. Reconstruction of Eroded and Visually Complicated Archaeological Geometric Patterns: Minaret Choli, Iraq

    Directory of Open Access Journals (Sweden)

    Rima Al Ajlouni

    2011-12-01

    Full Text Available Visually complicated patterns can be found in many cultural heritages of the world. Islamic geometric patterns present us with one example of such visually complicated archaeological ornaments. As long-lived artifacts, these patterns have gone through many phases of construction, damage, and repair and are constantly subject to erosion and vandalism. The task of reconstructing these visually complicated ornaments faces many practical challenges. The main challenge is posed by the fact that archaeological reality often deals with ornaments that are broken, incomplete or hidden. Recognizing faint traces of eroded or missing parts proved to be an extremely difficult task. This is also combined with the need for specialized knowledge about the mathematical rules of patterns’ structure, in order to regenerate the missing data. This paper presents a methodology for reconstructing deteriorated Islamic geometric patterns; to predict the features that are not observed and output a complete reconstructed two-dimension accurate measurable model. The simulation process depends primarily on finding the parameters necessary to predict information, at other locations, based on the relationships embedded in the existing data and in the prior -knowledge of these relations. The aim is to build up from the fragmented data and from the historic and general knowledge, a model of the reconstructed object. The proposed methodology was proven to be successful in capturing the accurate structural geometry of many of the deteriorated ornaments on the Minaret Choli, Iraq. However, in the case of extremely deteriorated samples, the proposed methodology failed to recognize the correct geometry. The conceptual framework proposed by this paper can serve as a platform for developing professional tools for fast and efficient results.

  1. Modification of the USLE K factor for soil erodibility assessment on calcareous soils in Iran

    Science.gov (United States)

    Ostovari, Yaser; Ghorbani-Dashtaki, Shoja; Bahrami, Hossein-Ali; Naderi, Mehdi; Dematte, Jose Alexandre M.; Kerry, Ruth

    2016-11-01

    The measurement of soil erodibility (K) in the field is tedious, time-consuming and expensive; therefore, its prediction through pedotransfer functions (PTFs) could be far less costly and time-consuming. The aim of this study was to develop new PTFs to estimate the K factor using multiple linear regression, Mamdani fuzzy inference systems, and artificial neural networks. For this purpose, K was measured in 40 erosion plots with natural rainfall. Various soil properties including the soil particle size distribution, calcium carbonate equivalent, organic matter, permeability, and wet-aggregate stability were measured. The results showed that the mean measured K was 0.014 t h MJ- 1 mm- 1 and 2.08 times less than the estimated mean K (0.030 t h MJ- 1 mm- 1) using the USLE model. Permeability, wet-aggregate stability, very fine sand, and calcium carbonate were selected as independent variables by forward stepwise regression in order to assess the ability of multiple linear regression, Mamdani fuzzy inference systems and artificial neural networks to predict K. The calcium carbonate equivalent, which is not accounted for in the USLE model, had a significant impact on K in multiple linear regression due to its strong influence on the stability of aggregates and soil permeability. Statistical indices in validation and calibration datasets determined that the artificial neural networks method with the highest R2, lowest RMSE, and lowest ME was the best model for estimating the K factor. A strong correlation (R2 = 0.81, n = 40, p soils.

  2. Simulated bat populations erode when exposed to climate change projections for western North America.

    Directory of Open Access Journals (Sweden)

    Mark A Hayes

    Full Text Available Recent research has demonstrated that temperature and precipitation conditions correlate with successful reproduction in some insectivorous bat species that live in arid and semiarid regions, and that hot and dry conditions correlate with reduced lactation and reproductive output by females of some species. However, the potential long-term impacts of climate-induced reproductive declines on bat populations in western North America are not well understood. We combined results from long-term field monitoring and experiments in our study area with information on vital rates to develop stochastic age-structured population dynamics models and analyzed how simulated fringed myotis (Myotis thysanodes populations changed under projected future climate conditions in our study area near Boulder, Colorado (Boulder Models and throughout western North America (General Models. Each simulation consisted of an initial population of 2,000 females and an approximately stable age distribution at the beginning of the simulation. We allowed each population to be influenced by the mean annual temperature and annual precipitation for our study area and a generalized range-wide model projected through year 2086, for each of four carbon emission scenarios (representative concentration pathways RCP2.6, RCP4.5, RCP6.0, RCP8.5. Each population simulation was repeated 10,000 times. Of the 8 Boulder Model simulations, 1 increased (+29.10%, 3 stayed approximately stable (+2.45%, +0.05%, -0.03%, and 4 simulations decreased substantially (-44.10%, -44.70%, -44.95%, -78.85%. All General Model simulations for western North America decreased by >90% (-93.75%, -96.70%, -96.70%, -98.75%. These results suggest that a changing climate in western North America has the potential to quickly erode some forest bat populations including species of conservation concern, such as fringed myotis.

  3. Quantifying sediment connectivity in an actively eroding gully complex, Waipaoa catchment, New Zealand

    Science.gov (United States)

    Taylor, Richard J.; Massey, Chris; Fuller, Ian C.; Marden, Mike; Archibald, Garth; Ries, William

    2018-04-01

    Using a combination of airborne LiDAR (2005) and terrestrial laser scanning (2007, 2008, 2010, 2011), sediment delivery processes and sediment connectivity in an 20-ha gully complex, which significantly contributes to the Waipaoa sediment cascade, are quantified over a 6-year period. The acquisition of terrain data from high-resolution surveys of the whole gully-fan system provides new insights into slope processes and slope-channel linkages operating in the complex. Raw terrain data from the airborne and ground-based laser scans were converted into raster DEMs with a vertical accuracy between surveys of models of change across the gully and fan complex. In these models deposition equates to positive and erosion to negative vertical change. Debris flows, slumping, and erosion by surface runoff (gullying in the conventional sense) generated on average 95,232 m3 of sediment annually, with a standard deviation of ± 20,806 m3. The volumes of debris eroded from those areas dominated by surface erosion processes were higher than in areas dominated by landslide processes. Over the six-year study period, sediment delivery from the source zones to the fan was a factor of 1.4 times larger than the volume of debris exported from the fan into Te Weraroa Stream. The average annual volume of sediment exported to Te Weraroa Stream varies widely from 23,195 to 102,796 m3. Fluctuations in the volume of stored sediment within the fan, rather than external forcing by rainstorms or earthquakes, account for this annual variation. No large rainfall events occurred during the monitoring period; therefore, sediment volumes and transfer processes captured by this study are representative of the background conditions that operate in this geomorphic system.

  4. Comparative study of soil erodibility and critical shear stress between loess and purple soils

    Science.gov (United States)

    Xing, Hang; Huang, Yu-han; Chen, Xiao-yan; Luo, Bang-lin; Mi, Hong-xing

    2018-03-01

    Loess and purple soils are two very important cultivated soils, with the former in the loess region and the latter in southern sub-tropical region of China, featured with high-risks of erosion, considerable differences of soil structures due to differences in mineral and nutrient compositions. Study on soil erodibility (Kr) and critical shear stress (τc) of these two soils is beneficial to predict soil erosion with such models as WEPP. In this study, rill erosion experimental data sets of the two soils are used for estimating their Kr and τc before they are compared to understand their differences of rill erosion behaviors. The maximum detachment rates of the loess and purple soils are calculated under different hydrodynamic conditions (flow rates: 2, 4, 8 L/min; slope gradients: 5°, 10°, 15°, 20°, 25°) through analytical and numerical methods respectively. Analytical method used the derivative of the function between sediment concentration and rill length to estimate potential detachment rates, at the rill beginning. Numerical method estimated potential detachment rates with the experimental data, at the rill beginning and 0.5 m location. The Kr and τc of these two soils are determined by the linear equation based on experimental data. Results show that the methods could well estimate the Kr and τc of these two soils as they remain basically unchanged under different hydrodynamic conditions. The Kr value of loess soil is about twice of the purple soil, whereas the τc is about half of that. The numerical results have good correlations with the analytical values. These results can be useful in modeling rill erosion processes of loess and purple soils.

  5. An integrated methodology to forecast the efficiency of nourishment strategies in eroding deltas.

    Science.gov (United States)

    Bergillos, Rafael J; López-Ruiz, Alejandro; Principal-Gómez, Daniel; Ortega-Sánchez, Miguel

    2018-02-01

    Many deltas across the globe are retreating, and nearby beaches are undergoing strong erosion as a result. Among soft and prompt solutions, nourishments are the most heavily used. This paper presents an integrated methodology to forecast the efficiency of nourishment strategies by means of wave climate simulations, wave propagations with downscaling techniques, computation of longshore sediment transport rates and application of the one-line model. It was applied to an eroding deltaic beach (Guadalfeo, southern Spain), where different scenarios as a function of the nourished coastline morphology, input volume and grain size were tested. For that, the evolution of six scenarios of coastline geometry over a two-year period (lifetime of nourishment projects at the study site) was modelled and the uncertainty of the predictions was also quantified through Monte Carlo techniques. For the most efficient coastline shape in terms of gained dry beach area, eight sub-scenarios with different nourished volumes were defined and modelled. The results indicate that an input volume around 460,000m 3 is the best strategy since nourished morphologies with higher volumes are more exposed to the prevailing storm directions, inducing less efficient responses. After setting the optimum coastline morphology and input sediment volume, eleven different nourished grain sizes were modelled; the most efficient coastline responses were obtained for sediment sizes greater than 0.01m. The availability of these sizes in the sediment accumulated upstream of a dam in the Guadalfeo River basin allows for the conclusion that this alternative would not only mitigate coastal erosion problems but also sedimentation issues in the reservoir. The methodology proposed in this work is extensible to other coastal areas across the world and can be helpful to support the decision-making process of artificial nourishment projects and other environmental management strategies. Copyright © 2017 Elsevier B.V. All

  6. The fate of eroded soil organic carbon along a European transect – controls after deposition in terrestrial and aquatic systems

    DEFF Research Database (Denmark)

    Kirkels, Frédérique; Cammeraat, Erik; Kalbitz, Karsten

    that the turnover of deposited C is significantly affected by soil and organic matter properties, and whether deposition occurs in terrestrial or aquatic environments. We sampled topsoils from 10 agricultural sites along a European transect, spanning a wide range of SOC and soil characteristics (e.g. texture......The potential fate of eroded soil organic carbon (SOC) after deposition is key to understand carbon cycling in eroding landscapes. Globally, large quantities of sediments and SOC are redistributed by soil erosion on agricul-tural land, particularly after heavy precipitation events. Deposition......, aggregation, C content, etc.). Turnover of SOC was determined for terrestrial and aquatic depositional conditions in a 10-week incubation study. Moreover, we studied the impact of labile carbon inputs (‘priming’) on SOC stability using 13C labelled cellulose. We evaluated potentially important controls...

  7. Initial Response of Pine Seedlings and Weeds to Dried Sewage Sludge in Rehabilitation of an Eroded Forest Site

    Science.gov (United States)

    Charles R. Berry

    1977-01-01

    Dried sewage sludge was applied at rates of 0, 17, 34, and 69 metric tons/ha on a badly eroded forest site in the Piedmont region of northeast Georgia. Production of weed bio mass varied directly with amount of sludge applied. Heigh growth for both shortleafand loblolly pine seedlings appeared to be greater on plots receiving 17 metric tons of sludge/ha, bu differences...

  8. Spatially variable rock erodibility in bedrock channels undergoing transient response to baselevel change, Great Falls area, Virginia

    OpenAIRE

    Shobe, Charles; Kee, Connor; Hancock, Gregory

    2018-01-01

    This is a poster that was presented in April 2014 at the Geological Society of America southeastern section meeting in Blacksburg, VA, USA. The poster presents rock strength and roughness data from tributaries to the Potomac River in Virginia. Our data support the idea that bedrock channel erodibility is greater on the channel margins than at the thalweg, which we hypothesize to be the result of weathering damage preferentially accumulated on the channel banks. This work was published in Shob...

  9. Evaluating the influence of feedbacks between erosion rate and weathering on the distribution of erodibility in bedrock river channels

    OpenAIRE

    Shobe, Charles; Hancock, Gregory; Eppes, Martha; Small, Eric

    2018-01-01

    This is a poster presented on November 3rd, 2015 at the Geological Society of America annual meeting in Baltimore, MD, USA. The poster presents rock strength and roughness data from tributaries to the Potomac River in Virginia. Our data support the idea that bedrock channel erodibility is greater on the channel margins than at the thalweg, which we hypothesize to be the result of weathering damage preferentially accumulated on the channel banks. This work was published in Shobe et al (2017; E...

  10. Effects of chronic anthropogenic disturbance and rainfall on the specialization of ant-plant mutualistic networks in the Caatinga, a Brazilian dry forest.

    Science.gov (United States)

    Câmara, Talita; Leal, Inara R; Blüthgen, Nico; Oliveira, Fernanda M P; Queiroz, Rubens T de; Arnan, Xavier

    2018-03-05

    Anthropogenic disturbance and climate change might negatively affect the ecosystem services provided by mutualistic networks. However, the effects of such forces remain poorly characterized. They may be especially important in dry forests, which (1) experience chronic anthropogenic disturbances (CADs) as human populations exploit forest resources, and (2) are predicted to face a 22% decline in rainfall under climate change. In this study, we investigated the separate and combined effects of CADs and rainfall levels on the specialization of mutualistic networks in the Caatinga, a seasonally dry tropical forest typical of north-eastern Brazil. More specifically, we examined interactions between plants bearing extrafloral nectaries (EFNs) and ants. We analysed whether differences in network specialization could arise from environmentally mediated variation in the species composition, namely via the replacement of specialist by generalist species. We characterized these ant-plant networks in 15 plots (20 × 20 m) that varied in CAD intensity and mean annual rainfall. We quantified CAD intensity by calculating three indices related to the main sources of disturbance in the Caatinga: livestock grazing (LG), wood extraction (WE) and miscellaneous resource use (MU). We determined the degree of ant-plant network specialization using four metrics: generality, vulnerability, interaction evenness and H 2 '. Our results indicate that CADs differentially influenced network specialization: we observed positive, negative, and neutral responses along LG, MU and WE gradients, respectively. The pattern was most pronounced with LG. Rainfall also shaped network specialization, markedly increasing it. While LG and rainfall were associated with changes in network species composition, this trend was not related to the degree of species specialization. This result suggests that shifts in network specialization might be related to changes in species behaviour, not species composition

  11. EROD activity and stable isotopes in seabirds to disentangle marine food web contamination after the Prestige oil spill

    International Nuclear Information System (INIS)

    Velando, Alberto; Munilla, Ignacio; Lopez-Alonso, Marta; Freire, Juan; Perez, Cristobal

    2010-01-01

    In this study, we measured via surgical sampling hepatic EROD activity in yellow-legged gulls from oiled and unoiled colonies, 17 months after the Prestige oil spill. We also analyzed stable isotope composition in feathers of the biopsied gulls, in an attempt to monitor oil incorporation into marine food web. We found that yellow-legged gulls in oiled colonies were being exposed to remnant oil as shown by hepatic EROD activity levels. EROD activity was related to feeding habits of individual gulls with apparent consequences on delayed lethality. Capture-recapture analysis of biopsied gulls suggests that the surgery technique did not affect gull survival, giving support to this technique as a monitoring tool for oil exposure assessment. Our study highlights the combination of different veterinary, toxicological and ecological methodologies as a useful approach for the monitoring of exposure to remnant oil after a large oil spill. - Two years after Prestige oil spill, seabirds were exposed to remnant oil related to their feeding habits with consequences on delayed lethality.

  12. EROD activity and stable isotopes in seabirds to disentangle marine food web contamination after the Prestige oil spill

    Energy Technology Data Exchange (ETDEWEB)

    Velando, Alberto, E-mail: avelando@uvigo.e [Departamento de Ecoloxia e Bioloxia Animal, Facultade de Ciencias, Universidade de Vigo, Campus As Lagoas, 36310 Vigo (Spain); Munilla, Ignacio [Departamento de Botanica, Facultade de Farmacia, Universidade de Santiago de Compostela, Santiago de Compostela (Spain); Lopez-Alonso, Marta [Departamento de Patoloxia Animal, Facultade de Veterinaria, Universidade de Santiago de Compostela, Lugo (Spain); Freire, Juan [Grupo de Recursos Marinos y Pesquerias Universidade da Coruna, A Coruna (Spain); Perez, Cristobal [Departamento de Ecoloxia e Bioloxia Animal, Facultade de Ciencias, Universidade de Vigo, Campus As Lagoas, 36310 Vigo (Spain)

    2010-05-15

    In this study, we measured via surgical sampling hepatic EROD activity in yellow-legged gulls from oiled and unoiled colonies, 17 months after the Prestige oil spill. We also analyzed stable isotope composition in feathers of the biopsied gulls, in an attempt to monitor oil incorporation into marine food web. We found that yellow-legged gulls in oiled colonies were being exposed to remnant oil as shown by hepatic EROD activity levels. EROD activity was related to feeding habits of individual gulls with apparent consequences on delayed lethality. Capture-recapture analysis of biopsied gulls suggests that the surgery technique did not affect gull survival, giving support to this technique as a monitoring tool for oil exposure assessment. Our study highlights the combination of different veterinary, toxicological and ecological methodologies as a useful approach for the monitoring of exposure to remnant oil after a large oil spill. - Two years after Prestige oil spill, seabirds were exposed to remnant oil related to their feeding habits with consequences on delayed lethality.

  13. Land degradation assessment by geo-spatially modeling different soil erodibility equations in a semi-arid catchment.

    Science.gov (United States)

    Saygın, Selen Deviren; Basaran, Mustafa; Ozcan, Ali Ugur; Dolarslan, Melda; Timur, Ozgur Burhan; Yilman, F Ebru; Erpul, Gunay

    2011-09-01

    Land degradation by soil erosion is one of the most serious problems and environmental issues in many ecosystems of arid and semi-arid regions. Especially, the disturbed areas have greater soil detachability and transportability capacity. Evaluation of land degradation in terms of soil erodibility, by using geostatistical modeling, is vital to protect and reclaim susceptible areas. Soil erodibility, described as the ability of soils to resist erosion, can be measured either directly under natural or simulated rainfall conditions, or indirectly estimated by empirical regression models. This study compares three empirical equations used to determine the soil erodibility factor of revised universal soil loss equation prediction technology based on their geospatial performances in the semi-arid catchment of the Saraykoy II Irrigation Dam located in Cankiri, Turkey. A total of 311 geo-referenced soil samples were collected with irregular intervals from the top soil layer (0-10 cm). Geostatistical analysis was performed with the point values of each equation to determine its spatial pattern. Results showed that equations that used soil organic matter in combination with the soil particle size better agreed with the variations in land use and topography of the catchment than the one using only the particle size distribution. It is recommended that the equations which dynamically integrate soil intrinsic properties with land use, topography, and its influences on the local microclimates, could be successfully used to geospatially determine sites highly susceptible to water erosion, and therefore, to select the agricultural and bio-engineering control measures needed.

  14. The evolution of stream coupled hillslopes by bedrock landsliding in a rapidly eroding mountain belt, Taiwan

    Science.gov (United States)

    Wenske, Dirk; Jen, Chia-Hung; Böse, Margot; Lin, Jiun-Chuan

    2010-05-01

    Being affected frequently by violent weather condition such as typhoons and regular seismic activity, the high mountains of Taiwan belong to the earth's most dynamic landscapes. In the fast-eroding mountain belt of Taiwan, hillslopes and valley systems have been reported to show a high level of coupling (Hovius et al. 2000). In the catchment of the Tachia river numerous bedrock landslides occur frequently as a result of seismic events and typhoons (Lin et al. 2006). This study attempts to take a closer look at the temporal and spatial pattern of hillslope evolution at two study sites in the upper catchement of the Tachia river. Therefore we have carried out a repeated field surveying of active slopes by means of traditional survey instruments and terrestrial laser scanning from early 2008 until late 2009 on a half year basis. Additionally, a set of aerial photos and satellite images from 1969, 1980,2001, 2004, 2007, 2008 and 2009 is used to assess the long-term and short-term changes of the river channel. Near the town of Huan Shan, the valley bottom shows elevations around 1520 m above sea level and the river is draining and upstream area of 155 km². Downstream of Huan Shan lies the confluence of the Tachia River and two of its tributaries, namely the Nanhu River and the Hehuan River. Therefore, the catchment area upstream of second study area in Sung Mao is considerably larger being of 420 km², in that place, the current level of the channel varies around 1425 m above sea level. In the two study areas strong lateral erosion has been observed. In the case of the Sung Mao study area, the latter is linked to a severe aggradation of sediments in the channel since the building of the Dechi Dam downstream. The active hillslopes have been surveyed and their reaction to the typhoons in 2008 and 2009 is studied. Rates of sediment yield from the slopes have been calculated for three periods between April 2008, November 2008, April 2009 and November 2009. Furthermore, the

  15. Effect of biocrust: study of mechanical and hydraulic properties and erodibility

    Science.gov (United States)

    Slavík, Martin; Bruthans, Jiří; Schweigstillová, Jana

    2016-04-01

    It is well-known that lichens and other organisms forming crust on soil or rock surface play important role in weathering but may also protect underlying material from fast erosion. So far, there have been only few measurements comparing mechanical or hydraulic properties of biocrust with its subsurface on locked sand and friable sandstones, so the overall effect of the biocrust is not well-understood. Objective of our study is to quantify the effect of the biocrust on mechanical and hydraulic properties of friable sandstone and locked sand of Cretaceous age in six different localities with varying aspect and inclination and age of exposure in sandpit Strelec (Czech Rep.). On the artificial exposures, biocrust developed within last 10-30 years. Beside measurements of mechanical and hydraulic properties, SEM and mercury intrusion porosimetry in crust and subsurface was performed. Drilling resistance technique was found an excellent method to distinguish the biocrust from its subsurface (~3 mm thick biocrust has up to 12 times higher drilling resistance than underlying material). Surface zone with the biocrust has 3 - 25 times higher tensile strength than the subsurface material (1 - 25 kPa). In comparison with the subsurface, the biocrust is considerably less erodible (based on water jet testing). Biocrust saturated hydraulic conductivity is 15 - 240 times lower than the subsurface (6*10 -5 - 1*10 -4 m/s) and its permeability for water vapor is 4 - 9 times lower than subsurface. Presence of the biocrust slows down capillary absorption of water 4 - 25 times. The biocrust is thus forming firm surface which protects underlying material from rain and flowing water erosion and which considerably modifies its hydraulic properties. Material with crust exposed to calcination, leaching by concentrated peroxide and experiments with zymoliase enzyme strongly indicate that major contribution to crust hardening is provided by organic matter. Based on DNA sequencing the crust is

  16. Deeply invasive candidiasis.

    NARCIS (Netherlands)

    Ostrosky-Zeichner, L.; Rex, J.H.; Bennett, J.; Kullberg, B.J.

    2002-01-01

    The incidence of invasive candidiasis is on the rise because of increasing numbers of immunocompromised hosts and more invasive medical technology. Recovery of Candida spp from several body sites in a critically ill or immunocompromised patient should raise the question of disseminated disease.

  17. Cryptic invasions: a review

    Czech Academy of Sciences Publication Activity Database

    Morais, Pedro Miguel; Reichard, Martin

    613-614, February (2018), s. 1438-1448 ISSN 0048-9697 R&D Projects: GA ČR GA13-05872S Institutional support: RVO:68081766 Keywords : Conspecific invader * Biological invasions * Bibliometric * Invasiveness Subject RIV: EG - Zoology OBOR OECD: Environmental sciences (social aspects to be 5.7) Impact factor: 4.900, year: 2016

  18. Factors influencing plant invasiveness

    Science.gov (United States)

    Yvette Ortega; Dean Pearson

    2009-01-01

    Invasiveness of spotted knapweed and biological control agents. Dean and Yvette are examining the influence of drought on the invasiveness of spotted knapweed (Centaurea maculosa) and its susceptibility to herbivory by biological control agents. In collaboration with the University of Montana and Forest Health Protection, researchers have constructed 150...

  19. Alien invasive birds.

    Science.gov (United States)

    Brochier, B; Vangeluwe, D; van den Berg, T

    2010-08-01

    A bird species is regarded as alien invasive if it has been introduced, intentionally or accidentally, to a location where it did not previously occur naturally, becomes capable of establishing a breeding population without further intervention by humans, spreads and becomes a pest affecting the environment, the local biodiversity, the economy and/or society, including human health. European Starling (Sturnus vulgaris), Common Myna (Acridotheres tristis) and Red-vented Bulbul (Pycnonotus cafer) have been included on the list of '100 of the World's Worst Invasive Alien Species', a subset of the Global Invasive Species Database. The 'Delivering Alien Invasive Species Inventories for Europe' project has selected Canada Goose (Branta canadensis), Ruddy Duck (Oxyura jamaicensis), Rose-ringed Parakeet (Psittacula krameri) and Sacred Ibis (Threskiornis aethiopicus) as among 100 of the worst invasive species in Europe. For each of these alien bird species, the geographic range (native and introduced range), the introduction pathway, the general impacts and the management methods are presented.

  20. Minimally invasive orthognathic surgery.

    Science.gov (United States)

    Resnick, Cory M; Kaban, Leonard B; Troulis, Maria J

    2009-02-01

    Minimally invasive surgery is defined as the discipline in which operative procedures are performed in novel ways to diminish the sequelae of standard surgical dissections. The goals of minimally invasive surgery are to reduce tissue trauma and to minimize bleeding, edema, and injury, thereby improving the rate and quality of healing. In orthognathic surgery, there are two minimally invasive techniques that can be used separately or in combination: (1) endoscopic exposure and (2) distraction osteogenesis. This article describes the historical developments of the fields of orthognathic surgery and minimally invasive surgery, as well as the integration of the two disciplines. Indications, techniques, and the most current outcome data for specific minimally invasive orthognathic surgical procedures are presented.

  1. The StreamCat Dataset: Accumulated Attributes for NHDPlusV2 Catchments (Version 2.1) for the Conterminous United States: Soil Erodibility (KFFACT)

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset represents the adjusted soil erodibility factor within individual, local NHDPlusV2 catchments and upstream, contributing watersheds. Attributes of the...

  2. Effects of land conversion from native shrub to pistachio orchard on soil erodibility in an arid region.

    Science.gov (United States)

    Yakupoglu, Tugrul; Gundogan, Recep; Dindaroglu, Turgay; Kara, Zekeriya

    2017-10-29

    Land-use change through degrading natural vegetation for agricultural production adversely affects many of soil properties particularly organic carbon content of soils. The native shrub land and grassland of Gaziantep-Adiyaman plateau that is an important pistachio growing eco-region have been cleared to convert into pistachio orchard for the last 50 to 60 years. In this study, the effects of conversion of natural vegetation into agricultural uses on soil erodibility have been investigated. Soil samples were collected from surface of agricultural fields and adjacent natural vegetation areas, and samples were analyzed for some soil erodibility indices such as dispersion ratio (DR), erosion ratio (ER), structural stability index (SSI), Henin's instability index (I s ), and aggregate size distribution after wet sieving (AggSD). According to the statistical evaluation, these two areas were found as different from each other in terms of erosion indices except for I s index (P < 0.001 for DR and ER or P < 0.01 for SSI). In addition, native shrub land and converted land to agriculture were found different in terms of AggSD in all aggregate size groups. As a contrary to expectations, correlation tests showed that there were no any interaction between soil organic carbon and measured erodibility indices in two areas. In addition, significant relationships were determined between measured variables and soil textural fractions as statistical. These obtaining findings were attributed to changing of textural component distribution and initial aggregate size distribution results from land-use change in the study area. Study results were explained about hierarchical aggregate formation mechanism.

  3. [Characteristics of Soil Respiration along Eroded Sloping Land with Different SOC Background on the Hilly Loess Plateau].

    Science.gov (United States)

    Chen, Gai; Xu, Ming-xiang; Zhang, Ya-feng; Wang, Chao-hua; Fan, Hui-min; Wang, Shan-shan

    2015-09-01

    This study aimed to characterize soil respiration along eroded sloping land at erosion and deposition area under different soil organic carbon(SOC) levels, and linked the relationship between soil respiration and soil temperature, soil moisture, SOC and slope position. Experiments were carried out in the plots of S type slopes include five different soil organic carbon levels in the Loess Hilly Region. The S type slopes were divided into control area at the top of the slope, erosion area at the middle of the slope and deposition area at the toe of the slope. We found that soil temperature had a greater impact on soil respiration in the deposition area, whereas soil moisture had a greater impact on soil respiration in the erosion area compared among control area, erosion area and deposition area. In addition, SOC was the most important factor affecting soil respiration, which can explain soil respiration variation 54. 72%, followed by soil moisture, slope position and soil temperature, which explain soil respiration variation 18. 86% , 16. 13% and 10. 29%, respectively. Soil respiration response to erosion showed obvious on-site and off-site effects along the eroded sloping land. Soil respiration in the erosion area was reduced by 21. 14% compared with control area, and soil respiration in the deposition area was increased by 21. 93% compared with control area. Erosion effect on source and sink of carbon emission was correlated with SOC content of the eroded sloping land. When SOC content was higher than 6. 82 g.kg-1, the slope. erosion tended to be a carbon sequestration process, and when SOC content was lower than 3.03 g.kg-1, the slope erosion tended to be a process of the carbon emission source. The model could reflect the relationship between soil respiration and independent variables of soil organic carbon content, soil temperature and moisture.

  4. Highly erodible terrain in agriculture land against chipped pruned branches. Or how to stop the soil erosion with low investment

    Science.gov (United States)

    Cerdà, A.

    2009-04-01

    The session on "Soil erosion and sediment control with vegetation and bioengineering on severely eroded terrain" pays special attention to the severe soil erosion suffered on steep slopes and erodible parent materials and soils. Within the last 20 years, in the Mediterranean lands, the citrus orchards were reallocated on steep slopes due to the urban development and better climatic and management conditions of the new plantations. The lack of vegetation cover on the new slope plantations of citrus resulted in high erosion rates. Those non-sustainable soil losses were measured by means of rainfall simulation experiments, Gerlach collectors, geomorphological transect and topographical measurements. The October 2007 and October 2008 rainy periods resulted in sheet, rill and gully erosion. Some recently planted orchards (2005) had the first pruning season in 2008. The pruned chipped branches reduced the soil losses to 50 % of the expected, although the litter (pruned branches) covered 4.67 % of the soil. This is why a research was developed by means of simulated rainfall experiments to determine the vegetation cover (litter, mainly leaves) to protect the soil to reach a sustainable erosion rate. Rainfall simulation experiments at 43 mm h-1 where performed on 1 m2 plots covered with 0, 3, 7, 15, 30, 45, 60, 80 and 100 % litter cover (pruned chipped branches) to determine the sustainable litter cover to avoid the soil losses. The results show that more that 45 % litter cover almost reduces the soil losses to negligible rates. The results confirm that 4 % of vegetation cover reduces the soil losses to 50 %. Key words: Agriculture land, erodible terrain, land management, citrus, erosion, Spain, Valencia, herbicides. Acknowledgements, We thanks the financial support of the Ministerio de Ciencia e Innovación by means of the project CGL2008-02879/BTE, "PERDIDA DE SUELO EN NUEVAS EXPLOTACIONES CITRICOLAS EN PENDIENTE. ESTRATEGIAS PARA EL CONTROL DE LA EROSION HIDRICA"

  5. Exotic mammals disperse exotic fungi that promote invasion by exotic trees.

    Science.gov (United States)

    Nuñez, Martin A; Hayward, Jeremy; Horton, Thomas R; Amico, Guillermo C; Dimarco, Romina D; Barrios-Garcia, M Noelia; Simberloff, Daniel

    2013-01-01

    Biological invasions are often complex phenomena because many factors influence their outcome. One key aspect is how non-natives interact with the local biota. Interaction with local species may be especially important for exotic species that require an obligatory mutualist, such as Pinaceae species that need ectomycorrhizal (EM) fungi. EM fungi and seeds of Pinaceae disperse independently, so they may use different vectors. We studied the role of exotic mammals as dispersal agents of EM fungi on Isla Victoria, Argentina, where many Pinaceae species have been introduced. Only a few of these tree species have become invasive, and they are found in high densities only near plantations, partly because these Pinaceae trees lack proper EM fungi when their seeds land far from plantations. Native mammals (a dwarf deer and rodents) are rare around plantations and do not appear to play a role in these invasions. With greenhouse experiments using animal feces as inoculum, plus observational and molecular studies, we found that wild boar and deer, both non-native, are dispersing EM fungi. Approximately 30% of the Pinaceae seedlings growing with feces of wild boar and 15% of the seedlings growing with deer feces were colonized by non-native EM fungi. Seedlings growing in control pots were not colonized by EM fungi. We found a low diversity of fungi colonizing the seedlings, with the hypogeous Rhizopogon as the most abundant genus. Wild boar, a recent introduction to the island, appear to be the main animal dispersing the fungi and may be playing a key role in facilitating the invasion of pine trees and even triggering their spread. These results show that interactions among non-natives help explain pine invasions in our study area.

  6. The evolution of size of the uropygial gland: mutualistic feather mites and uropygial secretion reduce bacterial loads of eggshells and hatching failures of European birds.

    Science.gov (United States)

    Soler, J J; Peralta-Sánchez, J M; Martín-Platero, A M; Martín-Vivaldi, M; Martínez-Bueno, M; Møller, A P

    2012-09-01

    Potentially, pathogenic bacteria are one of the main infective agents against which a battery of chemical and physical barriers has evolved in animals. Among these are the secretions by the exocrine uropygial gland in birds. The antimicrobial properties of uropygial secretions may prevent colonization and growth of microorganisms on feathers, skin and eggshells. However, uropygial gland secretions also favour the proliferation of feather mites that feed on secretions and microorganisms living on feathers that would otherwise reach eggshells during incubation if not consumed by feather mites. Therefore, at the interspecific level, uropygial gland size (as an index of volume of uropygial secretion) should be positively related to eggshell bacterial load (i.e. the risk of egg infection), whereas eggshell bacterial loads may be negatively related to abundance of feather mites eating bacteria. Here, we explore these previously untested predictions in a comparative framework using information on eggshell bacterial loads, uropygial gland size, diversity and abundance of feather mites and hatching success of 22 species of birds. The size of the uropygial gland was positively related to eggshell bacterial loads (mesophilic bacteria and Enterobacteriaceae), and bird species with higher diversity and abundance of feather mites harboured lower bacterial density on their eggshells (Enterococcus and Staphylococcus), in accordance with the hypothesis. Importantly, eggshell bacterial loads of mesophilic bacteria, Enterococcus and Enterobacteriaceae were negatively associated with hatching success, allowing us to interpret these interspecific relationships in a functional scenario, where both uropygial glands and mutualistic feather mites independently reduce the negative effects of pathogenic bacteria on avian fitness. © 2012 The Authors. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology.

  7. A proteomics approach to study the molecular basis of enhanced salt tolerance in barley (Hordeum vulgare L.) conferred by the root mutualistic fungus Piriformospora indica.

    Science.gov (United States)

    Alikhani, Mehdi; Khatabi, Behnam; Sepehri, Mozhgan; Nekouei, Mojtaba Khayam; Mardi, Mohsen; Salekdeh, Ghasem Hosseini

    2013-06-01

    Piriformospora indica is a root-interacting mutualistic fungus capable of enhancing plant growth, increasing plant resistance to a wide variety of pathogens, and improving plant stress tolerance under extreme environmental conditions. Understanding the molecular mechanisms by which P. indica can improve plant tolerance to stresses will pave the way to identifying the major mechanisms underlying plant adaptability to environmental stresses. We conducted greenhouse experiments at three different salt levels (0, 100 and 300 mM NaCl) on barley (Hordeum vulgare L.) cultivar "Pallas" inoculated with P. indica. Based on the analysis of variance, P. indica had a significant impact on the barley growth and shoot biomass under normal and salt stress conditions. P. indica modulated ion accumulation in colonized plants by increasing the foliar potassium (K(+))/sodium (Na(+)) ratio, as it is considered a reliable indicator of salt stress tolerance. P. indica induced calcium (Ca(2+)) accumulation and likely influenced the stress signal transduction. Subsequently, proteomic analysis of the barley leaf sheath using two-dimensional electrophoresis resulted in detection of 968 protein spots. Of these detected spots, the abundance of 72 protein spots changed significantly in response to salt treatment and P. indica-root colonization. Mass spectrometry analysis of responsive proteins led to the identification of 51 proteins. These proteins belonged to different functional categories including photosynthesis, cell antioxidant defense, protein translation and degradation, energy production, signal transduction and cell wall arrangement. Our results showed that P. indica induced a systemic response to salt stress by altering the physiological and proteome responses of the plant host.

  8. Contaminated soil phytoremediation by Cyperus laxus Lam. cytochrome p450 EROD-activity induced by hydrocarbons in roots.

    Science.gov (United States)

    López-Martínez, S; Gallegos-Martínez, M E; Pérez-Flores, L J; Gutiérrez-Rojas, M

    2008-01-01

    Laboratory and greenhouse experiments with Cyperus laxus Lam were conducted to determine the rate and extent of phytoremediation and the effect of hydrocarbons on the cytochrome P450 EROD (7-ethoxyresorufin-O-deethylase) enzymatic activity in roots. Plants were cultivated on hydrocarbon-contaminated soil (HCS) and spiked perlite. Phytoremediation was evaluated using 6.5 kg HCS (173 +/- 15 mg total petroleum hydrocarbons [TPH] g(-1) of dry soil) pots at different moisture contents; the average removal rate was 3.46-0.25 mg TPH g(-1) dry soil month(-1) and 48% was removed when moisture was kept at 60%. The aromatic hydrocarbon fraction was the mostly removed, 60%; aliphatic, 51%; and polar 24% after 24-month experiments. In unplanted pots, TPH concentration did not exhibit significant differences with respect to the initial concentration. We confirmed that the presence of hydrocarbons induced ERODactivity up to 6.5-fold. Moreover, short-term experiments (up to 13 d) with spiked perlite demonstrated that two EROD activities in roots contributed to the total detected; 60% was found in the cytosolic and 40% in the microsomal fraction. To our knowledge, this is the first work that tries to build links between the hydrocarbon-inducible character of ERODactivity in roots and the phytoremediation ability of C. laxus in highly contaminated soils.

  9. Effect of CPP-ACP on the remineralization of acid-eroded human tooth enamel: nanomechanical properties and microtribological behaviour study

    International Nuclear Information System (INIS)

    Zheng, L; Zheng, J; Zhang, Y F; Qian, L M; Zhou, Z R

    2013-01-01

    Casein phosphopeptide-stabilized amorphous calcium phosphate (CPP-ACP) has been used to enhance tooth remineralization in the dental clinic. But the contribution of CPP-ACP to the remineralization of acid-eroded human tooth enamel is of widespread controversy. To confirm the application potential of CPP-ACP in the remineralization repair of tooth erosion caused by acid-attack, the effect of remineralization in vitro in 2% w/v CPP-ACP solution on the acid-eroded human tooth enamel was investigated in this study. The repair of surface morphology and the improvement of nanomechanical and microtribological properties were characterized with laser confocal scanning microscope, scanning electron microscope, nanoindentation tester and nanoscratch tester. Results showed that a layer of uneven mineral deposits, which were mainly amorphous calcium phosphate (ACP) in all probability, was observed on the acid-eroded enamel surface after remineralization. Compared with the acid-eroded enamel surface, the nanoindentation hardness and Young's modulus of the remineralized enamel surface obviously increased. Both the friction coefficient and wear volume of the acid-eroded enamel surface decreased after remineralization. However, both the nanomechanical and the anti-wear properties of the remineralized enamel surface were still inferior to those of original enamel surface. In summary, tooth damage caused by acid erosion could be repaired by remineralization in CPP-ACP solution, but the repair effect, especially on the nanomechanical and anti-wear properties of the acid-eroded enamel, was limited. These results would contribute to a further exploration of the remineralization potential of CPP-ACP and a better understanding of the remineralization repair mechanism for acid-eroded human tooth enamel. (paper)

  10. Effect of CPP-ACP on the remineralization of acid-eroded human tooth enamel: nanomechanical properties and microtribological behaviour study

    Science.gov (United States)

    Zheng, L.; Zheng, J.; Zhang, Y. F.; Qian, L. M.; Zhou, Z. R.

    2013-10-01

    Casein phosphopeptide-stabilized amorphous calcium phosphate (CPP-ACP) has been used to enhance tooth remineralization in the dental clinic. But the contribution of CPP-ACP to the remineralization of acid-eroded human tooth enamel is of widespread controversy. To confirm the application potential of CPP-ACP in the remineralization repair of tooth erosion caused by acid-attack, the effect of remineralization in vitro in 2% w/v CPP-ACP solution on the acid-eroded human tooth enamel was investigated in this study. The repair of surface morphology and the improvement of nanomechanical and microtribological properties were characterized with laser confocal scanning microscope, scanning electron microscope, nanoindentation tester and nanoscratch tester. Results showed that a layer of uneven mineral deposits, which were mainly amorphous calcium phosphate (ACP) in all probability, was observed on the acid-eroded enamel surface after remineralization. Compared with the acid-eroded enamel surface, the nanoindentation hardness and Young's modulus of the remineralized enamel surface obviously increased. Both the friction coefficient and wear volume of the acid-eroded enamel surface decreased after remineralization. However, both the nanomechanical and the anti-wear properties of the remineralized enamel surface were still inferior to those of original enamel surface. In summary, tooth damage caused by acid erosion could be repaired by remineralization in CPP-ACP solution, but the repair effect, especially on the nanomechanical and anti-wear properties of the acid-eroded enamel, was limited. These results would contribute to a further exploration of the remineralization potential of CPP-ACP and a better understanding of the remineralization repair mechanism for acid-eroded human tooth enamel.

  11. Chinese tallow trees (Triadica sebifera) from the invasive range outperform those from the native range with an active soil community or phosphorus fertilization.

    Science.gov (United States)

    Zhang, Ling; Zhang, Yaojun; Wang, Hong; Zou, Jianwen; Siemann, Evan

    2013-01-01

    Two mechanisms that have been proposed to explain success of invasive plants are unusual biotic interactions, such as enemy release or enhanced mutualisms, and increased resource availability. However, while these mechanisms are usually considered separately, both may be involved in successful invasions. Biotic interactions may be positive or negative and may interact with nutritional resources in determining invasion success. In addition, the effects of different nutrients on invasions may vary. Finally, genetic variation in traits between populations located in introduced versus native ranges may be important for biotic interactions and/or resource use. Here, we investigated the roles of soil biota, resource availability, and plant genetic variation using seedlings of Triadica sebifera in an experiment in the native range (China). We manipulated nitrogen (control or 4 g/m(2)), phosphorus (control or 0.5 g/m(2)), soil biota (untreated or sterilized field soil), and plant origin (4 populations from the invasive range, 4 populations from the native range) in a full factorial experiment. Phosphorus addition increased root, stem, and leaf masses. Leaf mass and height growth depended on population origin and soil sterilization. Invasive populations had higher leaf mass and growth rates than native populations did in fresh soil but they had lower, comparable leaf mass and growth rates in sterilized soil. Invasive populations had higher growth rates with phosphorus addition but native ones did not. Soil sterilization decreased specific leaf area in both native and exotic populations. Negative effects of soil sterilization suggest that soil pathogens may not be as important as soil mutualists for T. sebifera performance. Moreover, interactive effects of sterilization and origin suggest that invasive T. sebifera may have evolved more beneficial relationships with the soil biota. Overall, seedlings from the invasive range outperformed those from the native range, however

  12. Growth and enzymatic activity of Leucoagaricus gongylophorus, a mutualistic fungus isolated from the leaf-cutting ant Atta mexicana, on cellulose and lignocellulosic biomass.

    Science.gov (United States)

    Vigueras, G; Paredes-Hernández, D; Revah, S; Valenzuela, J; Olivares-Hernández, R; Le Borgne, S

    2017-08-01

    A mutualistic fungus of the leaf-cutting ant Atta mexicana was isolated and identified as Leucoagaricus gongylophorus. This isolate had a close phylogenetic relationship with L. gongylophorus fungi cultivated by other leaf-cutting ants as determined by ITS sequencing. A subcolony started with ~500 A. mexicana workers could process 2 g day -1 of plant material and generate a 135 cm 3 fungus garden in 160 days. The presence of gongylidia structures of ~35 μm was observed on the tip of the hyphae. The fungus could grow without ants on semi-solid cultures with α-cellulose and microcrystalline cellulose and in solid-state cultures with grass and sugarcane bagasse, as sole sources of carbon. The maximum CO 2 production rate on grass (V max  = 17·5 mg CO 2  L g -1  day -1 ) was three times higher than on sugarcane bagasse (V max  = 6·6 mg CO 2  L g -1 day -1 ). Recoveries of 32·9 mg glucose  g biomass -1 and 12·3 mg glucose  g biomass -1 were obtained from the fungal biomass and the fungus garden, respectively. Endoglucanase activity was detected on carboxymethylcellulose agar plates. This is the first study reporting the growth of L. gongylophorus from A. mexicana on cellulose and plant material. According to the best of our knowledge, this is the first report about the growth of Leucoagaricus gongylophorus, isolated from the colony of the ant Atta mexicana, on semisolid medium with cellulose and solid-state cultures with lignocellulosic materials. The maximum CO 2 production rate on grass was three times higher than on sugarcane bagasse. Endoglucanase activity was detected and it was possible to recover glucose from the fungal gongylidia. The cellulolytic activity could be used to process lignocellulosic residues and obtain sugar or valuable products, but more work is needed in this direction. © 2017 The Society for Applied Microbiology.

  13. Effects of in vivo chronic exposure to pendimethalin on EROD activity and antioxidant defenses in rainbow trout (Oncorhynchus mykiss).

    Science.gov (United States)

    Danion, Morgane; Le Floch, Stéphane; Lamour, François; Quentel, Claire

    2014-01-01

    Pendimethalin, an herbicide active substance frequently used in terrestrial systems, has detected in European aquatic ecosystems. Reliable indicators still need to be found in order to properly assess the impact of pesticides in fish. After an in vivo chronic exposure to pendimethalin, the detoxification process and the antioxidant defense system were assessed in 120 adult rainbow trout, Oncorhynchus mykiss. Four nominal exposure conditions were tested: control (C), 500 ng L(-1) (P500), 800 ng L(-1) (P800) and the commercial formulation Prowl(®) at 500 ng L(-1) (Pw500). Fish samples were made after a 28 day exposure period (D28) and after a fifteen day recovery period in clean fresh water (D43). At D28, ethoxyresorufin-O-deethylase (EROD) activity was not activated in liver in spite of the pendimethalin uptake in fish. At D43, EROD activity in fish exposed to the commercial product was lower than in control fish, which may be explained by the high presence of herbicide in fish (613±163 ng g bile(-1)). Furthermore, antioxidant defense responses were set up by trout in gills and liver following chronic exposure to 800 ng L(-1) of pendimethalin concentration. While the glutathione content (GSH) decreased in gills, it increased in liver associated with higher activities of glutathione peroxidase (GPx) and superoxide dismutase (SOD). These disturbances could lead to reactive oxygen species production and oxidative stress in the vital organs in fish. After fifteen days in clean water, while the SOD activity was restored, the GSH content and GPx activity were still significantly disturbed in fish exposed to pendimethalin in comparison with control. These significant differences between treatments in antioxidant defenses parameters measured, attesting to the irreversibility of the effects. © 2013 Published by Elsevier Inc.

  14. Transvaginal Excision of an Eroded Sacrocolpopexy Mesh by Using Single-Incision Laparoscopic Surgery Equipment.

    Science.gov (United States)

    Mohr, Stefan; Siegenthaler, Franziska; Imboden, Sara; Kuhn, Annette; Mueller, Michael D

    To show a new technique of using single-incision laparoscopic surgery (SILS) equipment in vaginal surgery to create a "pneumovagina." Explanatory video demonstrating the technique and intraoperative findings. University hospital. The 68-year-old patient was referred with a vaginal mesh erosion that resulted in abscess formation at the vaginal apex. The patient was symptomatic with an increasingly foul-smelling vaginal discharge for about 1 year. She had a laparoscopic sacrocolpopexy in a remote hospital 22 months before the current operation and had a total abdominal hysterectomy 15 years ago. The, patient's history was uneventful without dyspareunia, incontinence or voiding difficulties, and she was otherwise content with the sacrocolpopexy result. The local institutional review board granted exemption for this publication. Frequently, pelvic organ prolapse can only be effectively treated if the surgical procedure comprises support of the central compartment. Laparoscopic sacrocolpopexy shows superior outcomes for this indication, with success rates of up to 96%. However, a rare side effect of laparoscopic sacrocolpopexy is mesh erosion, occurring in up to 2.4% [1]. These erosions are usually treated laparoscopically [2]. In this video we show an alternative route for excision of a symptomatic exposed mesh by using a transvaginal approach: The SILS trocar is used vaginally for abscess irrigation and mesh excision with minimally invasive instruments. For treatment of the abscess and removal of the exposed mesh, the SILS trocar was placed vaginally, and laparoscopic instruments were used. The abscess was incised, cleansed and irrigated, debrided, and the mesh excised. Because no mesh material was exposed after excision, the vagina was not closed to avoid creating a cavity with the risk of promoting reabscess formation, and secondary wound healing was anticipated. Laparoscopy was used to confirm that no intra-abdominal lesion coexisted or occurred. There were

  15. Exotic invasive plants

    Science.gov (United States)

    Carolyn Hull Sieg; Barbara G. Phillips; Laura P. Moser

    2003-01-01

    Ecosystems worldwide are threatened by nonnative plant invasions that can cause undesirable, irreversible changes. They can displace native plants and animals, out-cross with native flora, alter nutrient cycling and other ecosystem functions, and even change an ecosystem's flammability (Walker and Smith 1997). After habitat loss, the spread of exotic species is...

  16. Minimally invasive distal pancreatectomy

    NARCIS (Netherlands)

    Røsok, Bård I.; de Rooij, Thijs; van Hilst, Jony; Diener, Markus K.; Allen, Peter J.; Vollmer, Charles M.; Kooby, David A.; Shrikhande, Shailesh V.; Asbun, Horacio J.; Barkun, Jeffrey; Besselink, Marc G.; Boggi, Ugo; Conlon, Kevin; Han, Ho Seong; Hansen, Paul; Kendrick, Michael L.; Kooby, David; Montagnini, Andre L.; Palanivelu, Chinnasamy; Wakabayashi, Go; Zeh, Herbert J.

    2017-01-01

    The first International conference on Minimally Invasive Pancreas Resection was arranged in conjunction with the annual meeting of the International Hepato-Pancreato-Biliary Association (IHPBA), in Sao Paulo, Brazil on April 19th 2016. The presented evidence and outcomes resulting from the session

  17. Pathogenesis of invasive candidiasis.

    NARCIS (Netherlands)

    Veerdonk, F.L. van de; Kullberg, B.J.; Netea, M.G.

    2010-01-01

    PURPOSE OF REVIEW: Disseminated candidiasis remains a life-threatening disease in the ICU. The development of invasive disease with Candida albicans is dependent on multiple factors, such as colonization and efficient host defense at the mucosa. In the present review, we describe the host defense

  18. SymB and SymC, two membrane associated proteins, are required for Epichloë festucae hyphal cell-cell fusion and maintenance of a mutualistic interaction with Lolium perenne.

    Science.gov (United States)

    Green, Kimberly A; Becker, Yvonne; Tanaka, Aiko; Takemoto, Daigo; Fitzsimons, Helen L; Seiler, Stephan; Lalucque, Hervé; Silar, Philippe; Scott, Barry

    2017-02-01

    Cell-cell fusion in fungi is required for colony formation, nutrient transfer and signal transduction. Disruption of genes required for hyphal fusion in Epichloë festucae, a mutualistic symbiont of Lolium grasses, severely disrupts the host interaction phenotype. They examined whether symB and symC, the E. festucae homologs of Podospora anserina self-signaling genes IDC2 and IDC3, are required for E. festucae hyphal fusion and host symbiosis. Deletion mutants of these genes were defective in hyphal cell fusion, formed intra-hyphal hyphae, and had enhanced conidiation. SymB-GFP and SymC-mRFP1 localize to plasma membrane, septa and points of hyphal cell fusion. Plants infected with ΔsymB and ΔsymC strains were severely stunted. Hyphae of the mutants colonized vascular bundles, were more abundant than wild type in the intercellular spaces and formed intra-hyphal hyphae. Although these phenotypes are identical to those previously observed for cell wall integrity MAP kinase mutants no difference was observed in the basal level of MpkA phosphorylation or its cellular localization in the mutant backgrounds. Both genes contain binding sites for the transcription factor ProA. Collectively these results show that SymB and SymC are key components of a conserved signaling network for E. festucae to maintain a mutualistic symbiotic interaction within L. perenne. © 2016 The Authors. Molecular Microbiology Published by John Wiley & Sons Ltd.

  19. Management of invasive species

    DEFF Research Database (Denmark)

    Schou, Jesper Sølver; Jensen, Frank

    impact of the establishment of this invasive species is a substantial increase in the number of allergy cases, which we use as a measure of the physical damage. As valuation methods, we use both the cost-of-illness method and the benefit transfer method to quantify the total gross benefits of the two...... policy actions. Based on the idea of an invasion function, we identify the total and average net benefit under both prevention and mitigation. For both policy actions, the total and average net benefits are significantly positive irrespective of the valuation method used; therefore, both prevention...... and mitigation are beneficial policy actions. However, the total and average net benefits under mitigation are larger than the benefits under prevention, implying that the former policy action is more beneficial. Despite this result, we conclude that prevention, not mitigation, shall be used because...

  20. [Invasive nosocomial pulmonary aspergillosis].

    Science.gov (United States)

    Germaud, P; Haloun, A

    2001-04-01

    Immunodepressed patients, particularly those with neutropenia or bone marrow or organ grafts, are at risk of developing nosocomial invasive pulmonary aspergilosis. The favoring factors, early diagnostic criteria and curative treatment protocols are well known. Prognosis remains however quite severe with a death rate above 50%. Preventive measures are required for the treatment of these high-risk patients and epidemiology surveillance is needed in case of aspergillosis acquired in the hospital.

  1. Toxicity of sediments from Bahía de Chetumal, México, as assessed by hepatic EROD induction and histology in nile tilapia Oreochromis niloticus.

    Science.gov (United States)

    Zapata-Pérez, O; Simá-Alvarez, R; Noreña-Barroso, E; Güemes, J; Gold-Bouchot, G; Ortega, A; Albores-Medina, A

    2000-01-01

    The effect of environmental pollutants present in sediments obtained from Bahía de Chetumal, a bay on the border between Mexico and Belize, was studied in nile tilapia (Oreochromis niloticus) intraperitoneally injected with sediment extracts from six different sites of the Bay. Sediment samples used for the study contained a variety of organic chemicals such as organochlorine pesticides, polychlorinated biphenyls (PCBs) and polynuclear aromatic hydrocarbons (PAHs). Total cytochrome P-450 and EROD activity were measured in fish liver. Haematological and histological analyses were also carried out. Hepatic P-450 content in treated fish increased from 43 to 240%, and EROD activity from 85 to 160% compared to controls. Extracts from two sampling sites inhibited EROD activity. There were positive significant correlations between P-450 content and the levels of PCBs 44 and 128. EROD activity correlated to HCB, op'-DDE, pp'-DDE, pp'-DDD, mirex and PCB 18 concentrations. Blood examination showed cell degeneration and binucleated leukocytes with abnormal chromatin. Extract treatment also resulted in foci of hyperplasia on the basement of gill lamellae, hypertrophy and oedema in gills and liver necrosis. Control fish showed no abnormalities. The results demonstrate that sediments from Bahía of Chetumal have the potential to cause histopathological, haematological and biochemical alterations in fish. The administration of sediment extracts to fish may serve as a useful test to screen the toxicity of sediments from different areas.

  2. Plant invasions: Merging the concepts of species invasiveness and community invasibility

    Czech Academy of Sciences Publication Activity Database

    Richardson, D. M.; Pyšek, Petr

    2006-01-01

    Roč. 30, č. 3 (2006), s. 409-431 ISSN 0309-1333 Institutional research plan: CEZ:AV0Z60050516 Keywords : plant invasions * species invasiveness * community invasibility Subject RIV: EF - Botanics Impact factor: 1.278, year: 2006

  3. The effects of the mineral phase on C stabilization mechanisms and the microbial community along an eroding slope transect

    Science.gov (United States)

    Doetterl, S.; Opfergelt, S.; Cornelis, J.; Boeckx, P. F.; van oost, K.; Six, J.

    2013-12-01

    An increasing number of studies show the importance of including soil redistribution processes in understanding carbon (C) dynamics in eroding landscapes. The quality and quantity of soil organic carbon in sloping cropland differs with topographic position. These differences are commonly more visible in the subsoil, while the size and composition of topsoil C pools are similar along the hillslope. The type (plant- or microbial-derived) and quality (level of degradation) of C found in a specific soil fraction depends on the interplay between the temporal dynamic of the specific mechanism and it's strength to protect C from decomposition. Here, we present an analysis that aims to clarify the bio/geo-chemical and mineralogical components involved in stabilizing C at various depths and slope positions and how they affect the microbial community and the degradation of C. For this we analyzed soil samples from different soil depths along a slope transect applying (i) a sequential extraction of the reactive soil phase using pyrophosphate, oxalate and dithionite-citrate-bicarbonate, (ii) a semi-quantitative and qualitative analysis of the clay mineralogy, (iii) an analysis of the microbial community using amino sugars and (iv) an analysis of the level of degradation of C in different soil fractions focusing on the soil Lignin signature. The results show that the pattern of minerals and their relative importance in stabilizing C varies greatly along the transect. In the investigated soils, pyrophosphate extractable Manganese, and not Iron or Aluminum as often observed, is strongly correlated to C in the bulk soil and in the non-aggregated silt and clay fractions. This suggests a certain role of Manganese for C stabilization where physical protection is absent. In contrast, pyrophosphate extractable Iron and Aluminum components are largely abundant in water-stable soil aggregates but not correlated to C, suggesting importance of these extracts to stabilize aggregates and

  4. Effect of farmyard manure, mineral fertilizers and mung bean residues on some microbiological properties of eroded soil in district Swat

    Directory of Open Access Journals (Sweden)

    M. Naeem

    2009-05-01

    Full Text Available The present study was conducted to evaluate the efficacy of organic and inorganic fertilizers and mung bean residues on improving microbiological properties of eroded lands of District Swat, North West Frontier Province (NWFP Pakistan under wheat-mung bean-wheat cropping system during 2006 to 2008. The experiment was laid out in RCBD split-plot arrangement. Mung bean was grown and a basal dose of 25-60 kg N-P2O5 ha-1 was applied. After mung bean harvest, three residues management practices, i.e., R+ (mung bean residues incorporated into soil, R- (mung bean residues removed and F (fallow were performed in the main-plots. Sub-plot factor consisted of six fertilizer treatments for wheat crop i.e., T1 (control, T2 (120 kg N ha-1, T3 (120-90-0 kg N-P2O5-K2O ha-1, T4 (120-90-60 kg N-P2O5-K2O ha-1, T5 (90-90-60 kg N-P2O5-K2O + 10 t FYM ha-1 and T6 (60-90-60 kg N-P2O5- K2O + 20 t FYM ha-1. The results showed that microbial activity, microbial biomass-C and-N, mineralizable C and N were highest with T6 as well as with the incorporation of mung bean residues (R+. Compared with control, T6 increased microbial biomass C, N, mineralizable C and N by 33.8, 164.1, 35.5 and 110.6% at surface and 38.4, 237.5, 38.7 and 124.1% at sub-surface soil, respectively, while R+ compared with fallow increased these properties by 33.7, 47.4, 21.4 and 32.2% at surface and 36.8, 51, 21.9 and 35.4% at sub-surface soil, respectively. Inclusion of mung bean with its residues incorporated and application of 20 t FYM ha-1 and reducing inorganic N fertilizer to 60 kg N ha-1 for wheat is recommended for improving microbiological properties of slightly eroded lands

  5. Insect-flower interaction network structure is resilient to a temporary pulse of floral resources from invasive Rhododendron ponticum.

    Directory of Open Access Journals (Sweden)

    Erin Jo Tiedeken

    Full Text Available Invasive alien plants can compete with native plants for resources, and may ultimately decrease native plant diversity and/or abundance in invaded sites. This could have consequences for native mutualistic interactions, such as pollination. Although invasive plants often become highly connected in plant-pollinator interaction networks, in temperate climates they usually only flower for part of the season. Unless sufficient alternative plants flower outside this period, whole-season floral resources may be reduced by invasion. We hypothesized that the cessation of flowering of a dominant invasive plant would lead to dramatic, seasonal compositional changes in plant-pollinator communities, and subsequent changes in network structure. We investigated variation in floral resources, flower-visiting insect communities, and interaction networks during and after the flowering of invasive Rhododendron ponticum in four invaded Irish woodland sites. Floral resources decreased significantly after R. ponticum flowering, but the magnitude of the decrease varied among sites. Neither insect abundance nor richness varied between the two periods (during and after R. ponticum flowering, yet insect community composition was distinct, mostly due to a significant reduction in Bombus abundance after flowering. During flowering R. ponticum was frequently visited by Bombus; after flowering, these highly mobile pollinators presumably left to find alternative floral resources. Despite compositional changes, however, network structural properties remained stable after R. ponticum flowering ceased: generality increased, but quantitative connectance, interaction evenness, vulnerability, H'2 and network size did not change. This is likely because after R. ponticum flowering, two to three alternative plant species became prominent in networks and insects increased their diet breadth, as indicated by the increase in network-level generality. We conclude that network structure

  6. Quantifying the eroded volume of mercury-contaminated sediment using terrestrial laser scanning at Stocking Flat, Deer Creek, Nevada County, California, 2010–13

    Science.gov (United States)

    Howle, James F.; Alpers, Charles N.; Bawden, Gerald W.; Bond, Sandra

    2016-07-28

    High-resolution ground-based light detection and ranging (lidar), also known as terrestrial laser scanning, was used to quantify the volume of mercury-contaminated sediment eroded from a stream cutbank at Stocking Flat along Deer Creek in the Sierra Nevada foothills, about 3 kilometers west of Nevada City, California. Terrestrial laser scanning was used to collect sub-centimeter, three-dimensional images of the complex cutbank surface, which could not be mapped non-destructively or in sufficient detail with traditional surveying techniques.The stream cutbank, which is approximately 50 meters long and 8 meters high, was surveyed on four occasions: December 1, 2010; January 20, 2011; May 12, 2011; and February 4, 2013. Volumetric changes were determined between the sequential, three-dimensional lidar surveys. Volume was calculated by two methods, and the average value is reported. Between the first and second surveys (December 1, 2010, to January 20, 2011), a volume of 143 plus or minus 15 cubic meters of sediment was eroded from the cutbank and mobilized by Deer Creek. Between the second and third surveys (January 20, 2011, to May 12, 2011), a volume of 207 plus or minus 24 cubic meters of sediment was eroded from the cutbank and mobilized by the stream. Total volumetric change during the winter and spring of 2010–11 was 350 plus or minus 28 cubic meters. Between the third and fourth surveys (May 12, 2011, to February 4, 2013), the differencing of the three-dimensional lidar data indicated that a volume of 18 plus or minus 10 cubic meters of sediment was eroded from the cutbank. The total volume of sediment eroded from the cutbank between the first and fourth surveys was 368 plus or minus 30 cubic meters.

  7. Flow and transport through a damaged buffer - exploration of the impact of a cemented and an eroded buffer

    Energy Technology Data Exchange (ETDEWEB)

    Neretnieks, Ivars [Dept. of Chemical Engineering and Technology, Royal Institute of Technology, Stockholm (Sweden)

    2006-12-15

    The compacted bentonite buffer that surrounds the canister with spent fuel is designed not to allow water to flow through it in any appreciable quantities. Should the buffer be severely damaged water could flow to the canister and bring with it corrosive agent such as sulphide. This could speed up the rate of copper corrosion. Should the canister have a damage or be corroded so that the spent fuel inside the canister comes in contact with the water radionuclides could dissolve in the water and be carried away. Two modes of canister damage and their consequences for solute transport are explored in this report. In one case the buffer can potentially be eroded by the water seeping in the fractures in the surrounding rock and attain a high hydraulic conductivity allowing water to flow through it, at least locally. In another case it is conjectured that the buffer is cemented and becomes brittle. Then a crack could conceivably form in the cemented buffer allowing water to flow through it directly to the canister surface. Both cases are hypothetical although in the erosion case the erosion rate could possibly be quantified. The cases studied are to be seen as exploratory calculations for 'what if' cases. Some worst case assumptions have been used to explore bounding scenarios. Thus for the erosion case it is assumed that the hydraulic conductivity is so high that the buffer exerts negligible resistance to water flow. This implies that all the water that can flow through the fractures intersecting the deposition hole can reach the canister. Similarly for the cemented buffer case it is assumed that the crack in the buffer directly connects the rock fracture to the canister surface. For these circumstances it is found that the flowrate that can enter the deposition hole will be approximately two times as large as the water flow that would pass a projected area equal to that of the deposition hole. Thus if the flux in the rock some distance from the deposition

  8. INDIRECT ASSESSMENT OF RIVER-TORRENTIAL EROSION BY MEASURING THE ERODED VOLUM CASE STUDY: THE REGHIU STREAM

    Directory of Open Access Journals (Sweden)

    NICULAE LUCICA

    2014-03-01

    Full Text Available The landform, as a whole, is the basic component of the environment and evolves as an open system controlled by two categories of components, in a close relationship of dynamic interconditioning. The endodynamic components are stable and they define the relief physiognomy: hypsometry, the gradient and length of the slope, lithologic conditions and the drainage density. The exodynamic components, with high spatial and temporal mobility, control the flow of matter and energy within the hydrographic basin, the solar energy, the rainfalls, the temperature, the plant cover, and the anthropic activity. The volume of eroded material of a hydrographic basin will set the relationship between the present physiognomy of the landform and the flow of materials carried and discharged. The quantitative evaluation of the erosion in a hydrographic basin, specific to a certain region, will deal with the parameters reflecting the intensity of the morphogenetic processes over a specified period of time. The Reghiu Stream, a left-side tributary of the River Milcov, drains varied landforms, developed on geological formations with different physical properties; moreover, it manifests a regressive erosion, weaker than the Zabala River (they used to have a common evolution during the geological past, and the interfluve is very narrow – there are few facts which lead to the conclusion that the erosion is differential, depending on the local conditions of shaping.

  9. Does market integration buffer risk, erode traditional sharing practices and increase inequality? A test among Bolivian forager-farmers.

    Science.gov (United States)

    Gurven, Michael; Jaeggi, Adrian V; von Rueden, Chris; Hooper, Paul L; Kaplan, Hillard

    2015-08-01

    Sharing and exchange are common practices for minimizing food insecurity in rural populations. The advent of markets and monetization in egalitarian indigenous populations presents an alternative means of managing risk, with the potential impact of eroding traditional networks. We test whether market involvement buffers several types of risk and reduces traditional sharing behavior among Tsimane Amerindians of the Bolivian Amazon. Results vary based on type of market integration and scale of analysis (household vs. village), consistent with the notion that local culture and ecology shape risk management strategies. Greater wealth and income were unassociated with the reliance on others for food, or on reciprocity, but wealth was associated with a greater proportion of food given to others (i.e., giving intensity) and a greater number of sharing partners (i.e., sharing breadth). Across villages, greater mean income was negatively associated with reciprocity, but economic inequality was positively associated with giving intensity and sharing breadth. Incipient market integration does not necessarily replace traditional buffering strategies but instead can often enhance social capital.

  10. Flow and transport through a damaged buffer - exploration of the impact of a cemented and an eroded buffer

    International Nuclear Information System (INIS)

    Neretnieks, Ivars

    2006-12-01

    The compacted bentonite buffer that surrounds the canister with spent fuel is designed not to allow water to flow through it in any appreciable quantities. Should the buffer be severely damaged water could flow to the canister and bring with it corrosive agent such as sulphide. This could speed up the rate of copper corrosion. Should the canister have a damage or be corroded so that the spent fuel inside the canister comes in contact with the water radionuclides could dissolve in the water and be carried away. Two modes of canister damage and their consequences for solute transport are explored in this report. In one case the buffer can potentially be eroded by the water seeping in the fractures in the surrounding rock and attain a high hydraulic conductivity allowing water to flow through it, at least locally. In another case it is conjectured that the buffer is cemented and becomes brittle. Then a crack could conceivably form in the cemented buffer allowing water to flow through it directly to the canister surface. Both cases are hypothetical although in the erosion case the erosion rate could possibly be quantified. The cases studied are to be seen as exploratory calculations for 'what if' cases. Some worst case assumptions have been used to explore bounding scenarios. Thus for the erosion case it is assumed that the hydraulic conductivity is so high that the buffer exerts negligible resistance to water flow. This implies that all the water that can flow through the fractures intersecting the deposition hole can reach the canister. Similarly for the cemented buffer case it is assumed that the crack in the buffer directly connects the rock fracture to the canister surface. For these circumstances it is found that the flowrate that can enter the deposition hole will be approximately two times as large as the water flow that would pass a projected area equal to that of the deposition hole. Thus if the flux in the rock some distance from the deposition hole is 1

  11. Minimally Invasive Parathyroidectomy

    Directory of Open Access Journals (Sweden)

    Lee F. Starker

    2011-01-01

    Full Text Available Minimally invasive parathyroidectomy (MIP is an operative approach for the treatment of primary hyperparathyroidism (pHPT. Currently, routine use of improved preoperative localization studies, cervical block anesthesia in the conscious patient, and intraoperative parathyroid hormone analyses aid in guiding surgical therapy. MIP requires less surgical dissection causing decreased trauma to tissues, can be performed safely in the ambulatory setting, and is at least as effective as standard cervical exploration. This paper reviews advances in preoperative localization, anesthetic techniques, and intraoperative management of patients undergoing MIP for the treatment of pHPT.

  12. Quantifying the invasiveness of species

    Directory of Open Access Journals (Sweden)

    Robert Colautti

    2014-04-01

    Full Text Available The success of invasive species has been explained by two contrasting but non-exclusive views: (i intrinsic factors make some species inherently good invaders; (ii species become invasive as a result of extrinsic ecological and genetic influences such as release from natural enemies, hybridization or other novel ecological and evolutionary interactions. These viewpoints are rarely distinguished but hinge on distinct mechanisms leading to different management scenarios. To improve tests of these hypotheses of invasion success we introduce a simple mathematical framework to quantify the invasiveness of species along two axes: (i interspecific differences in performance among native and introduced species within a region, and (ii intraspecific differences between populations of a species in its native and introduced ranges. Applying these equations to a sample dataset of occurrences of 1,416 plant species across Europe, Argentina, and South Africa, we found that many species are common in their native range but become rare following introduction; only a few introduced species become more common. Biogeographical factors limiting spread (e.g. biotic resistance, time of invasion therefore appear more common than those promoting invasion (e.g. enemy release. Invasiveness, as measured by occurrence data, is better explained by inter-specific variation in invasion potential than biogeographical changes in performance. We discuss how applying these comparisons to more detailed performance data would improve hypothesis testing in invasion biology and potentially lead to more efficient management strategies.

  13. The immediate effectiveness of barley straw mulch in reducing soil erodibility and surface runoff generation in Mediterranean vineyards.

    Science.gov (United States)

    Prosdocimi, Massimo; Jordán, Antonio; Tarolli, Paolo; Keesstra, Saskia; Novara, Agata; Cerdà, Artemi

    2016-03-15

    Soil and water loss in agriculture is a major problem throughout the world, and especially in Mediterranean areas. Non-conservation agricultural practices have further aggravated the situation, especially in vineyards, which are affected by one of the highest rates of soil loss among cultivated lands. Therefore, it is necessary to find the right soil practices for more sustainable viticulture. In this regard, straw mulching has proven to be effective in other crop and fire affected soils, but, nonetheless, little research has been carried out in vineyards. This research tests the effect of barley straw mulching on soil erosion and surface runoff on vineyards in Eastern Spain where the soil and water losses are non-sustainable. An experiment was setup using rainfall simulation tests at 55 mm h(-1) over 1h on forty paired plots of 0.24 m(2): twenty bare and twenty straw covered. Straw cover varied from 48 to 90% with a median value of 59% as a result of the application of 75 g of straw per m(2). The use of straw mulch resulted in delayed ponding and runoff generation and, as a consequence, the median water loss decreased from 52.59 to 39.27% of the total rainfall. The straw cover reduced the median sediment concentration in runoff from 9.8 to 3.0 g L(-1) and the median total sediment detached from 70.34 to 15.62 g per experiment. The median soil erosion rate decreased from 2.81 to 0.63 Mg ha(-1)h(-1) due to the straw mulch protection. Straw mulch is very effective in reducing soil erodibility and surface runoff, and this benefit was achieved immediately after the application of the straw. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Microbial invasion of the Caribbean by an Indo-Pacific coral zooxanthella.

    Science.gov (United States)

    Pettay, D Tye; Wham, Drew C; Smith, Robin T; Iglesias-Prieto, Roberto; LaJeunesse, Todd C

    2015-06-16

    Human-induced environmental changes have ushered in the rapid decline of coral reef ecosystems, particularly by disrupting the symbioses between reef-building corals and their photosymbionts. However, escalating stressful conditions enable some symbionts to thrive as opportunists. We present evidence that a stress-tolerant "zooxanthella" from the Indo-Pacific Ocean, Symbiodinium trenchii, has rapidly spread to coral communities across the Greater Caribbean. In marked contrast to populations from the Indo-Pacific, Atlantic populations of S. trenchii contained exceptionally low genetic diversity, including several widespread and genetically similar clones. Colonies with this symbiont tolerate temperatures 1-2 °C higher than other host-symbiont combinations; however, calcification by hosts harboring S. trenchii is reduced by nearly half, compared with those harboring natives, and suggests that these new symbioses are maladapted. Unforeseen opportunism and geographical expansion by invasive mutualistic microbes could profoundly influence the response of reef coral symbioses to major environmental perturbations but may ultimately compromise ecosystem stability and function.

  15. A comparison of non-invasive versus invasive methods of ...

    African Journals Online (AJOL)

    Puneet Khanna

    for Hb estimation from the laboratory [total haemoglobin mass (tHb)] and arterial blood gas (ABG) machine (aHb), using ... A comparison of non-invasive versus invasive methods of haemoglobin estimation in patients undergoing intracranial surgery. 161 .... making decisions for blood transfusions based on these results.

  16. Mutualism and Adaptive Divergence: Co-Invasion of a Heterogeneous Grassland by an Exotic Legume-Rhizobium Symbiosis

    Science.gov (United States)

    Porter, Stephanie S.; Stanton, Maureen L.; Rice, Kevin J.

    2011-01-01

    Species interactions play a critical role in biological invasions. For example, exotic plant and microbe mutualists can facilitate each other's spread as they co-invade novel ranges. Environmental context may influence the effect of mutualisms on invasions in heterogeneous environments, however these effects are poorly understood. We examined the mutualism between the legume, Medicago polymorpha, and the rhizobium, Ensifer medicae, which have both invaded California grasslands. Many of these invaded grasslands are composed of a patchwork of harsh serpentine and relatively benign non-serpentine soils. We grew legume genotypes collected from serpentine or non-serpentine soil in both types of soil in combination with rhizobium genotypes from serpentine or non-serpentine soils and in the absence of rhizobia. Legumes invested more strongly in the mutualism in the home soil type and trends in fitness suggested that this ecotypic divergence was adaptive. Serpentine legumes had greater allocation to symbiotic root nodules in serpentine soil than did non-serpentine legumes and non-serpentine legumes had greater allocation to nodules in non-serpentine soil than did serpentine legumes. Therefore, this invasive legume has undergone the rapid evolution of divergence for soil-specific investment in the mutualism. Contrary to theoretical expectations, the mutualism was less beneficial for legumes grown on the stressful serpentine soil than on the non-serpentine soil, possibly due to the inhibitory effects of serpentine on the benefits derived from the interaction. The soil-specific ability to allocate to a robust microbial mutualism may be a critical, and previously overlooked, adaptation for plants adapting to heterogeneous environments during invasion. PMID:22174755

  17. Mutualism and adaptive divergence: co-invasion of a heterogeneous grassland by an exotic legume-rhizobium symbiosis.

    Directory of Open Access Journals (Sweden)

    Stephanie S Porter

    Full Text Available Species interactions play a critical role in biological invasions. For example, exotic plant and microbe mutualists can facilitate each other's spread as they co-invade novel ranges. Environmental context may influence the effect of mutualisms on invasions in heterogeneous environments, however these effects are poorly understood. We examined the mutualism between the legume, Medicago polymorpha, and the rhizobium, Ensifer medicae, which have both invaded California grasslands. Many of these invaded grasslands are composed of a patchwork of harsh serpentine and relatively benign non-serpentine soils. We grew legume genotypes collected from serpentine or non-serpentine soil in both types of soil in combination with rhizobium genotypes from serpentine or non-serpentine soils and in the absence of rhizobia. Legumes invested more strongly in the mutualism in the home soil type and trends in fitness suggested that this ecotypic divergence was adaptive. Serpentine legumes had greater allocation to symbiotic root nodules in serpentine soil than did non-serpentine legumes and non-serpentine legumes had greater allocation to nodules in non-serpentine soil than did serpentine legumes. Therefore, this invasive legume has undergone the rapid evolution of divergence for soil-specific investment in the mutualism. Contrary to theoretical expectations, the mutualism was less beneficial for legumes grown on the stressful serpentine soil than on the non-serpentine soil, possibly due to the inhibitory effects of serpentine on the benefits derived from the interaction. The soil-specific ability to allocate to a robust microbial mutualism may be a critical, and previously overlooked, adaptation for plants adapting to heterogeneous environments during invasion.

  18. A Hydrodynamic and Sediment Transport Model for the Waipaoa Shelf, New Zealand: Sensitivity of Fluxes to Spatially-Varying Erodibility and Model Nesting

    Directory of Open Access Journals (Sweden)

    Julia M. Moriarty

    2014-04-01

    Full Text Available Numerical models can complement observations in investigations of marine sediment transport and depositional processes. A coupled hydrodynamic and sediment transport model was implemented for the Waipaoa River continental shelf offshore of the North Island of New Zealand, to complement a 13-month field campaign that collected seabed and hydrodynamic measurements. This paper described the formulations used within the model, and analyzed the sensitivity of sediment flux estimates to model nesting and seabed erodibility. Calculations were based on the Regional Ocean Modeling System—Community Sediment Transport Modeling System (ROMS-CSTMS, a primitive equation model using a finite difference solution to the equations for momentum and water mass conservation, and transport of salinity, temperature, and multiple classes of suspended sediment. The three-dimensional model resolved the complex bathymetry, bottom boundary layer, and river plume that impact sediment dispersal on this shelf, and accounted for processes including fluvial input, winds, waves, tides, and sediment resuspension. Nesting within a larger-scale, lower resolution hydrodynamic model stabilized model behavior during river floods and allowed large-scale shelf currents to impact sediment dispersal. To better represent observations showing that sediment erodibility decreased away from the river mouth, the seabed erosion rate parameter was reduced with water depth. This allowed the model to account for the observed spatial pattern of erodibility, though the model held the critical shear stress for erosion constant. Although the model neglected consolidation and swelling processes, use of a spatially-varying erodibility parameter significantly increased export of fluvial sediment from Poverty Bay to deeper areas of the shelf.

  19. Some heterocyclic aromatic compounds are Ah receptor agonists in the DR-CALUX assay and the EROD assay with RTL-W1 cells.

    Science.gov (United States)

    Hinger, Gunnar; Brinkmann, Markus; Bluhm, Kerstin; Sagner, Anne; Takner, Helena; Eisenträger, Adolf; Braunbeck, Thomas; Engwall, Magnus; Tiehm, Andreas; Hollert, Henner

    2011-09-01

    Heterocyclic aromatic compounds containing nitrogen, sulfur, or oxygen heteroatoms (NSO-HET) have been detected in air, soil, marine, and freshwater systems. However, only few publications are available investigating NSO-HET using in vitro bioassays. To support better characterization of environmental samples, selected NSO-HET were screened for dioxin-like activity in two bioassays. The present study focuses on the identification and quantification of dioxin-like effects of 12 NSO-HET using the DR-CALUX assay, and the 7-ethoxyresorufin-O-deethylase (EROD) assay with the permanent fish liver cell line RTL-W1. Changes of the total medium compound concentrations during the test procedure due to, e.g., sorption or volatilization were quantified using GC/MS. The NSO-HET benzofuran, 2,3-dimethylbenzofuran, dibenzofuran, dibenzothiophen, acridine, xanthene, and carbazole caused a response in the DR-CALUX assay. Only benzofuran and 2,3-dimethylbenzofuran were also positive in the EROD assay. All other compounds were inactive in the EROD assay. Relative potency (REP) values ranged from (2.80 ± 1.32) · 10(-8) to (3.26 ± 2.03) · 10(-6) in the DR-CALUX and from (3.26 ± 0.91) · 10(-7) to (4.87 ± 1.97) · 10(-7) in the EROD assay. The REP values were comparable to those of larger polycyclic aromatic hydrocarbons, e.g., fluoranthene and pyrene. Thus, and because of the ubiquitous distribution of heterocyclic aromatic compounds in the environment, the provided data will further facilitate the bioanalytical and analytical characterization of environmental samples towards these toxicants.

  20. Klebsiella pneumoniae Invasive Syndrome

    Directory of Open Access Journals (Sweden)

    Vasco Evangelista

    2018-01-01

    Full Text Available Klebsiella pneumoniae invasive syndrome (KPIS is a rare clinical condition characterized by primary liver abscess associated with metastatic infection. Most case reports are from Southeast Asia, with only one case described in Portugal. The Authors present the case of a 44-year-old man with a history of fever, dry cough and cervicalgia. A thoracic computed tomography (CT scan showed multiple pulmonary and hepatic nodules, suggestive of metastatic malignancy. Both blood cultures and bronchoalveolar lavage were positive for Klebsiella pneumoniae. Imaging studies were repeated during his hospital stay, showing a reduction in both number and volume of identified lesions, thus revealing their infectious nature. This case illustrates how much this entity can mimic other illnesses.

  1. Dietary Flexibility Aids Asian Earthworm Invasion in North American Forests

    Science.gov (United States)

    On a local scale, invasiveness of introduced species and invasibility of habitats together determine invasion success. A key issue in invasion ecology has been how to quantify the contribution of species invasiveness and habitat invasibility separately. Conventional approaches, s...

  2. Microbial ecology of biological invasions

    NARCIS (Netherlands)

    Van der Putten, W.H.; Klironomos, J.N.; Wardle, D.A.

    2007-01-01

    Invasive microbes, plants and animals are a major threat to the composition and functioning of ecosystems; however, the mechanistic basis of why exotic species can be so abundant and disruptive is not well understood. Most studies have focused on invasive plants and animals, although few have

  3. Invasive tightly coupled processor arrays

    CERN Document Server

    LARI, VAHID

    2016-01-01

    This book introduces new massively parallel computer (MPSoC) architectures called invasive tightly coupled processor arrays. It proposes strategies, architecture designs, and programming interfaces for invasive TCPAs that allow invading and subsequently executing loop programs with strict requirements or guarantees of non-functional execution qualities such as performance, power consumption, and reliability. For the first time, such a configurable processor array architecture consisting of locally interconnected VLIW processing elements can be claimed by programs, either in full or in part, using the principle of invasive computing. Invasive TCPAs provide unprecedented energy efficiency for the parallel execution of nested loop programs by avoiding any global memory access such as GPUs and may even support loops with complex dependencies such as loop-carried dependencies that are not amenable to parallel execution on GPUs. For this purpose, the book proposes different invasion strategies for claiming a desire...

  4. Towards a better understanding of the interaction between bed roughness and flow hydraulics in small eroded channels

    Science.gov (United States)

    Giménez, Rafael; Zubieta, Elena; Campo-Bescós, Miguel A.; Casalí, Javier

    2016-04-01

    Rills eroding cohesive materials are hydraulically different from rivers or large channels. Unlike rivers, rills are small, shallow flow stream with frequently a relatively steep slope gradient. Besides, rills evolve morphologically over much shorter timescales due to active bed erosion. This leads to a strong interaction between the channel flow and bed roughness. This interaction gives rise to a reconfiguration of the bed geometry generated by the important erosive action of the flow. This new shape is characterized by a typical alternance between concavities (pools) and more or less flat reaches (steps). The new rill geometry affects, in turn, the behaviour of the flow that is why we talk about interaction or feedback. In addition, the greatest energy dissipation occurs in the pools -mainly due to the action of hydraulic jumps- which, in turn, lead to an increase in the pool size. We hypothesize there is a regular spacing of step-pools units and that, both the frequency and the depth of the pools will be strongly conditioned by the discharge and the general rill slope. The determination of that periodicity (if any) would be an important contribution for concentrated flow erosion modelling of small channels. That is because the majority of erosion models are based on formulations which assume that a rill has a flat bed, only affected by micro-roughness. For instance, equations like Manning's - widely used in river and large channel hydraulics -, if a constant value of roughness is assumed, would be inappropriate in erosion rills since, as explained above, the roughness is not constant. The objectives of this work are then: (i) to investigate the geometry of erosion rills aiming at determining if there is a spatial arrangement of the macro roughness of their beds; and (ii) to establish (semi)-empirical models of prediction of this periodicity, mainly based on topographic parameters. Rills were generated in an agricultural field in a homogeneous hillslope (with no

  5. [Invasive pulmonary aspergillosis].

    Science.gov (United States)

    Blanchard, E; Gabriel, F; Jeanne-Leroyer, C; Servant, V; Dumas, P-Y

    2018-02-01

    Invasive pulmonary aspergillosis (IPA) is an important cause of morbidity and mortality in a wide range of patients. Early recognition and diagnosis have become a major focus in improving the management and outcomes of this life-threatening disease. IPA typically occurs during a period of severe and prolonged neutropenia. However, solid organ transplant recipients, patients under immunosuppressive therapy or hospitalized in intensive care units are also at risk. The diagnosis is suspected in the presence of a combination of clinical, biological and CT scan evidence. The microbiological diagnostic strategy should be adapted to the patient's profile. Conventional methods with culture and species identification remain the standard but early diagnosis has been improved by the use of biomarkers such as galactomannan antigen in serum or in bronchoalveolar lavage. The epidemiology of IPA should change with the increased use of antifungal prophylactic regimens and the arrival of targeted therapies. Other microbiological tools, such as PCR and other biomarkers, are currently being assessed. IPA must be considered in a wide range of patients. Its prognosis remains poor despite progress in the microbiological diagnosis and therapeutic management. Copyright © 2018 SPLF. Published by Elsevier Masson SAS. All rights reserved.

  6. Non-invasive hemoglobin monitoring.

    Science.gov (United States)

    Joseph, Bellal; Haider, Ansab; Rhee, Peter

    2016-09-01

    Technology has transformed the practice of medicine and surgery in particular over the last several decades. This change in practice has allowed diagnostic and therapeutic tests to be performed less invasively. Hemoglobin monitoring remains one of the most commonly performed diagnostic tests in the United States. Recently, non-invasive hemoglobin monitoring technology has gained popularity. The aim of this article is to review the principles of how this technology works, pros and cons, and the implications of non-invasive hemoglobin technology particularly in trauma surgery. Copyright © 2015 IJS Publishing Group Ltd. Published by Elsevier Ltd. All rights reserved.

  7. Micafungin in the treatment of invasive candidiasis and invasive aspergillosis

    Directory of Open Access Journals (Sweden)

    Nathan P Wiederhold

    2009-01-01

    Full Text Available Nathan P Wiederhold1, Jason M Cota2, Christopher R Frei11University of Texas at Austin College of Pharmacy, Austin, Texas, USA; 2University of the Incarnate Word Feik School of Pharmacy, San Antonio, Texas, USAAbstract: Micafungin is an echinocandin antifungal agent available for clinical use in Japan, Europe, and the United States. Through inhibition of β-1,3-glucan production, an essential component of the fungal cell wall, micafungin exhibits potent antifungal activity against key pathogenic fungi, including Candida and Aspergillus species, while contributing minimal toxicity to mammalian cells. This activity is maintained against polyene and azole-resistant isolates. Pharmacokinetic and pharmacodynamic studies have demonstrated linear kinetics both in adults and children with concentration-dependent activity observed both in vitro and in vivo. Dosage escalation studies have also demonstrated that doses much higher than those currently recommended may be administered without serious adverse effects. Clinically, micafungin has been shown to be efficacious for the treatment of invasive candidiasis and invasive aspergillosis. Furthermore, the clinical effectiveness of micafungin against these infections occurs without the drug interactions that occur with the azoles and the nephrotoxicity observed with amphotericin B formulations. This review will focus on the pharmacology, clinical microbiology, mechanisms of resistance, safety, and clinical efficacy of micafungin in the treatment of invasive candidiasis and invasive aspergillosis.Keywords: micafungin, echinocandin, Candida, Aspergillus, invasive candidiasis, invasive aspergillosis

  8. Squamous cell carcinoma - invasive (image)

    Science.gov (United States)

    This irregular red nodule is an invasive squamous cell carcinoma (a form of skin cancer). Initial appearance, shown here, may be very similar to a noncancerous growth called a keratoacanthoma. Squamous cell cancers ...

  9. The mathematics behind biological invasions

    CERN Document Server

    Lewis, Mark A; Potts, Jonathan R

    2016-01-01

    This book investigates the mathematical analysis of biological invasions. Unlike purely qualitative treatments of ecology, it draws on mathematical theory and methods, equipping the reader with sharp tools and rigorous methodology. Subjects include invasion dynamics, species interactions, population spread, long-distance dispersal, stochastic effects, risk analysis, and optimal responses to invaders. While based on the theory of dynamical systems, including partial differential equations and integrodifference equations, the book also draws on information theory, machine learning, Monte Carlo methods, optimal control, statistics, and stochastic processes. Applications to real biological invasions are included throughout. Ultimately, the book imparts a powerful principle: that by bringing ecology and mathematics together, researchers can uncover new understanding of, and effective response strategies to, biological invasions. It is suitable for graduate students and established researchers in mathematical ecolo...

  10. Invasive Meningococcal Men Y Disease

    Centers for Disease Control (CDC) Podcasts

    2012-04-18

    Dr. Leonard Mayer, a public health microbiologist at CDC, discusses invasive meningococcal disease.  Created: 4/18/2012 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 4/23/2012.

  11. Quantifying the invasiveness of species

    Czech Academy of Sciences Publication Activity Database

    Colautti, R. I.; Parker, J. D.; Cadotte, M. W.; Pyšek, Petr; Brown, C. S.; Sax, D. F.; Richardson, D. M.

    2014-01-01

    Roč. 21, č. 1 (2014), s. 7-27 ISSN 1619-0033 R&D Projects: GA ČR(CZ) GAP505/11/1112; GA ČR(CZ) GAP504/11/1028 Grant - others:AV ČR(CZ) AP1002 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:67985939 Keywords : biological invasions * biogeographical comparison * invasiveness Subject RIV: EH - Ecology, Behaviour

  12. Erosion of the Alps: use of Rb-Sr isotopic data from molassic sediments to identify the ages of the metamorphism recorded by the eroded rocks

    International Nuclear Information System (INIS)

    Henry, P.; Deloule, E.

    1994-01-01

    Rb-Sr isotopic data from Oligocene and Miocene peri-alpine molassic sediments allow us to identify the different periods for which the eroded rocks have or have not recorded an alpine metamorphism. The Chattian and the Burdigalian sediments result from the erosion of rocks for which the latest metamorphic event was variscan, while the Stampian, Aquitanian and ''Helvetian'' sediments show evidence for the erosion of rocks which have recorded alpine metamorphic events. The application of this method to old detrital sediments could permit determination of the ages of the tectonic events which occurred in the sediment source regions. (authors). 18 refs., 6 figs

  13. Reconstruction of eroded and deposited sediment volumes in the floodplains of the embanked River Waal, the Netherlands, for the period 1650 - 1850 AD

    Science.gov (United States)

    Hobo, Noortje; Makaske, Bart; Middelkoop, Hans

    2010-05-01

    The embanked floodplains of the River Waal developed as a result of stepwise downstream migration of meander bends between confining dykes. Accretion in the upstream limb of the outer bend - enhanced by groynes and trees - and erosion in the downstream limb have resulted in a series of successively developed sand bars, separated by secondary channels. On top of the sand bars and the secondary channel fills, fine-grained overbank sediments were deposited. Downstream migration ceased around 1850 AD, when the river bed was fixed by large-scale construction of groynes, and only overbank deposition continued. Eroded and deposited sediment volumes associated with downstream migration are affected by human activities. Goal of the present research is to estimate a sediment budget for a 12-km-long section along the River Waal, by quantifying the amount of erosion and deposition. We estimated these volumes for time slices of 50 years, between 1650 and 1850 AD, in order to be able to assess the variable impact of human interference during this period. To estimate erosion, we created geomorphological maps for all time slices, based on maps dating from the 17th century to present. In these maps, distinction is made between sand bars, residual channels, and older deposits (all sediments deposited before 1650 AD). Comparison between all maps allowed us to calculate the eroded area per time slice. Eroded volumes were hence estimated by multiplying the eroded area by the average river depth at that period, which is assumed to be the erosion depth. For estimation of deposition we used lithological cross-sections. These cross-sections are positioned such that every sand bar and every residual channel is represented in at least one cross-section. In every cross-section isochrones were drawn, based on OSL datings, chronologic interpretation of heavy metal profiles, and the historical maps. These isochrones are used to calculate the thickness of the sand bars, the residual channel fills

  14. Risk assessment of PCDD/Fs levels in human tissues related to major food items based on chemical analyses and micro-EROD assay.

    Science.gov (United States)

    Tsang, H L; Wu, S C; Wong, C K C; Leung, C K M; Tao, S; Wong, M H

    2009-10-01

    Nine groups of food items (freshwater fish, marine fish, pork, chicken, chicken eggs, leafy, non-leafy vegetables, rice and flour) and three types of human samples (human milk, maternal serum and cord serum) were collected for the analysis of PCDD/Fs. Results of chemical analysis revealed PCDD/Fs concentrations (pg g(-1) fat) in the following ascending order: pork (0.289 pg g(-1) fat), grass carp (Ctenopharyngodon idellus) (freshwater fish) (0.407), golden thread (Nemipterus virgatus) (marine fish) (0.511), chicken (0.529), mandarin fish (Siniperca kneri) (marine fish) (0.535), chicken egg (0.552), and snubnose pompano (Trachinotus blochii) (marine fish) (1.219). The results of micro-EROD assay showed relatively higher PCDD/Fs levels in fish (2.65 pg g(-1) fat) when compared with pork (0.47), eggs (0.33), chicken (0.13), flour (0.07), vegetables (0.05 pg g(-1) wet wt) and rice (0.05). The estimated average daily intake of PCDD/Fs of 3.51 pg EROD-TEQ/kg bw/day was within the range of WHO Tolerable Daily Intake (1-4 pg WHO-TEQ/kg bw/day) and was higher than the Provisional Tolerable Daily Intake (PMTL) (70 pg for dioxins and dioxin-like PCBs) recommended by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) [Joint FAO/WHO Expert Committee on Food Additives (JECFA), Summary and conclusions of the fifty-seventh meeting, JECFA, 2001.]. Nevertheless, the current findings were significantly lower than the TDI (14 pg WHO-TEQ/kg/bw/day) recommended by the Scientific Committee on Food of the Europe Commission [European Scientific Committee on Food (EU SCF), Opinions on the SCF on the risk assessment of dioxins and dioxin-like PCBs in food, 2000.]. However, it should be noted that micro-EROD assay overestimates the PCDD/Fs levels by 2 to 7 folds which may also amplify the PCDD/Fs levels accordingly. Although the levels of PCDD/Fs obtained from micro-EROD assay were much higher than those obtained by chemical analysis by 2 to 7 folds, it provides a cost-effective and

  15. Evaluation of entomopathogenic nematodes and the supernatants of the in vitro culture medium of their mutualistic bacteria for the control of the root-knot nematodes Meloidogyne incognita and M. arenaria.

    Science.gov (United States)

    Kepenekci, Ilker; Hazir, Selcuk; Lewis, Edwin E

    2016-02-01

    The suppressive effects of various formulations of four entomopathogenic nematode (EPN) species and the supernatants of their mutualistic bacteria on the root-knot nematodes (RKNs) Meloidogyne incognita and M. arenaria in tomato roots were evaluated. The EPNs Steinernema carpocapsae, S. feltiae, S. glaseri and Heterorhabditis bacteriophora were applied as either live infective juveniles (IJs) or infected insect cadavers. Spent medium from culturing the bacterial symbionts Xenorhabdus bovienii and Photorhabdus luminescens kayaii with the cells removed was also applied without their nematode partners. The aqueous suspensions of IJs, infected cadaver applications of EPNs and especially treatments of X. bovienii supernatant suppressed the negative impact of RKNs on tomatoes. Specific responses to treatment were reduced RKN egg masses, increased plant height and increased fresh and dry weights compared with the control where only RKNs were applied. Among the treatments tested, the plant-dipping method of X. bovienii into bacterial culture fluid may be the most practical and effective method for M. incognita and M. arenaria control. © 2015 Society of Chemical Industry.

  16. A meta-analysis of trait differences between invasive and non-invasive plant species

    OpenAIRE

    van Kleunen, Mark; Weber, Ewald; Fischer, Markus

    2010-01-01

    A major aim in ecology is identifying determinants of invasiveness. We performed a meta-analysis of 117 field or experimental-garden studies that measured pair-wise trait differences of a total of 125 invasive and 196 non-invasive plant species in the invasive range of the invasive species. We tested whether invasiveness is associated with performance-related traits (physiology, leaf-area allocation, shoot allocation, growth rate, size and fitness), and whether such associations depend on typ...

  17. Remineralization of eroded enamel by a NaF rinse containing a novel calcium phosphate agent in an in situ model: a pilot study

    Directory of Open Access Journals (Sweden)

    Bennett T Amaechi

    2010-08-01

    Full Text Available Bennett T Amaechi1, Ramalingam Karthikeyan1, Poornima K Mensinkai1, Kaveh Najibfard1, Allen C Mackey2, Robert L Karlinsey21University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA; 2Indiana Nanotech, Indianapolis, IN, USAPurpose: An in situ study evaluated the remineralization potential of 225 ppm fluoride (F rinses with and without a calcium phosphate agent (TCP-Si-Ur on eroded enamel.Methods: 20 human patients participated in this IRB approved study. Enamel blocks extracted from 20 human molars were assigned to each of the three study phases (G1, G2, G3. Each block was eroded using 1% citric acid (pH = 2.5, with a slice cut from each block to establish baseline lesion parameters (ie, integrated mineral loss ∆Z, and lesion depth LD using ­transverse microradiography (TMR. Participants and assigned blocks were randomly divided into three 28-day phases. The blocks were mounted into modified orthodontic brackets and bonded to the buccal surface of one of the subject’s mandibular molars. The appliance remained in the ­subject’s mouth for 28 days. Prior to each study phase, participants observed a one-week-washout period using a fluoride-free dentifrice. In each phase, participants brushed with the fluoride-free ­dentifrice for 1 min, followed by one of the following coded treatments: G1: 225 ppm F + 40 ppm ­TCP-Si-Ur rinse (1 min; G2: 225 ppm F rinse (1 min; G3: no rinse (saliva-only. After each phase, appliances were removed and specimens were analyzed using TMR.Results: TMR data (ie, ∆Z and LD revealed all three groups significantly remineralized eroded enamel (paired t-tests, P , 0.001. Net mineralization (% change in ∆Z, LD were as follows (mean (std.dev.: G1: 44.1 (22.6, 30.5 (27.0; G2: 30.0 (7.4, 29.4 (10.5; G3: 23.8 (16.4, 25.7 (15.5. Furthermore, G1 was found to cause significantly more remineralization than G2 (P = 0.039 and G3, (P = 0.002.Conclusion: Mouthrinse containing 225 ppm F plus TCP

  18. Eroding dipoles and vorticity growth for Euler flows in {{{R}}}^{3}: the hairpin geometry as a model for finite-time blowup

    Science.gov (United States)

    Childress, Stephen; Gilbert, Andrew D.

    2018-02-01

    A theory of an eroding ‘hairpin’ vortex dipole structure in three-dimensions is developed, extending our previous study of an axisymmetric eroding dipole without swirl. The axisymmetric toroidal dipole was found to lead to maximal growth of vorticity, as {t}4/3. The hairpin is here similarly proposed as a model to produce large ‘self-stretching’ of vorticity, with the possibility of finite-time blow-up. We derive a system of partial differential equations of ‘generalized’ form, involving contour averaging of a locally two-dimensional Euler flow. We do not attempt here to solve the system exactly, but point out that non-existence of physically acceptable solutions would most probably be a result of the axial flow. Because of the axial flow the vorticity distribution within the dipole eddies is no longer of the simple Sadovskii type (vorticity constant over a cross-section) obtained in the axisymmetric problem. Thus the solution of the system depends upon the existence of a larger class of propagating two-dimensional dipoles. The hairpin model is obtained by formal asymptotic analysis. As in the axisymmetric problem a local transformation to ‘shrinking’ coordinates is introduced, but now in a self-similar form appropriate to the study of a possible finite-time singularity. We discuss some properties of the model, including a study of the helicity and a first step in iterating toward a solution from the Sadovskii structure. We also present examples of two-dimensional propagating dipoles not previously studied, which have a vorticity profile consistent with our model. Although no rigorous results can be given, and analysis of the system is only partial, the formal calculations are consistent with the possibility of a finite time blowup of vorticity at a point of vanishing circulation of the dipole eddies, but depending upon the existence of the necessary two-dimensional propagating dipole. Our results also suggest that conservation of kinetic energy as

  19. Low-temperature thermal decomposition of dioxin-like compounds in fly ash: combination of chemical analysis with in vitro bioassays (EROD and DR-CALUX).

    Science.gov (United States)

    Behnisch, Peter A; Hosoe, Kazunori; Shiozaki, Ken; Ozaki, Hironori; Nakamura, Kazuo; Sakai, Shin-Ichi

    2002-12-01

    To investigate the dechlorination of fly ash during low-temperature treatment under oxygen-deficient conditions (thermocatalyic treatment or Hagenmaier process), six fly ash samples from six different incineration plants were treated in a laboratory experiment or in the actual plant, either under ideal (400 degrees C, 120 min) or intermediate (300 degrees C, 30 min) conditions. The aim of the present study was to confirm the decrease in the I-TEQ (international toxicity equivalency) of polychlorinated dibenzo-p-dioxins/-furans (PCDD/Fs) and coplanar polychlorinated biphenyls (co-PXBs) and, also for the first time, the decrease in the sum of dioxin-like toxicity (bioassay- or bio-TEQ) of all kinds of other dioxin-like Ah receptor agonists (such as PXDD/Fs, PXBs, PXN, X = Br, F) measured by two state-of-the-art cell-based Ah receptor-dependent bioassays: H4IIE-Ethoxy-Resorufin-o-Deethylase (EROD) and H4IIE-luc/DR-Chemical Activated Luciferase expression (DR-CALUX). The treatment efficiency was calculated on the basis of the reduction in the I-TEQ and bio-TED values. For these fly ash samples, the treatment efficiency, as measured by chemical analysis, was higher than 99%, and 85%-99%, in the case of the bio-TED values, indicating that these Ah receptor binding toxic compounds were sufficiently decomposed. Bio-TEQ values for untreated fly ash samples (n = 6) were on average 1.2 times (range 0.7-1.9), for the H4IIE-EROD assay, and 2.8 times (1.1-4.9), for the DR-CALUX assay, higher than I-TEQ values measured by chemical analyses (sum of PCDD/Fs and co-PCBs). In the case of these fly ash samples treated under ideal conditions and therefore low in contaminants, the bio-TEQ values were on average 1.4 times (range 0.9-1.8), for the H4IIE-EROD assay, and 5.1 times (range 1.2-12), for the DR-CALUX assay, higher than the I-TEQ values.

  20. Advertising and Invasion of Privacy.

    Science.gov (United States)

    Rohrer, Daniel Morgan

    The right of privacy as it relates to advertising and the use of a person's name or likeness is discussed in this paper. After an introduction that traces some of the history of invasion of privacy in court decisions, the paper examines cases involving issues such as public figures and newsworthy items, right of privacy waived, right of privacy…

  1. Radiological characterization of invasive prolactinomas

    International Nuclear Information System (INIS)

    Mauricio, J.C.; Goulao, A.; Ribeiro, C.; Campos, J.

    1983-01-01

    Clinical problems are analized of invasive prolactinomas, from the radiographic records of the Hospital Egas Moniz (Neuro-radiological Departament). The purpose of this paper is contribute for the anatomic-radiological knowledge and clinical progress, under medical treatment, of the macroprolactinomas that have some characteristics that differentiate them from the small adenomas. (Author) [pt

  2. Biological invasions in forest ecosystems

    Science.gov (United States)

    Andrew M. Liebhold; Eckehard G. Brockerhoff; Susan Kalisz; Martin A. Nuñez; David A. Wardle; Michael J. Wingfield

    2017-01-01

    Forests play critical roles in global ecosystem processes and provide numerous services to society. But forests are increasingly affected by a variety of human influences, especially those resulting from biological invasions. Species invading forests include woody and herbaceous plants, many animal species including mammals and invertebrates, as well as a variety of...

  3. Invasive cranial mycosis our experiences

    Directory of Open Access Journals (Sweden)

    Tapas Kumbhkar

    2013-01-01

    Full Text Available Fungi can cause serious cranial infections in immunocompromised and diabetic patients. Common pathogens mainly include Aspergillus and Mucor. These organisms cause tissue invasion and destruction of adjacent structures (e.g. orbit, ethmoid, sphenoid, maxillary & cavernous sinuses. Mortality and morbidity rate is high despite combined surgical, antifungal and antidiabetic treatment. We present our experience of six cases with such infection.

  4. Vaccines against invasive Salmonella disease

    Science.gov (United States)

    MacLennan, Calman A; Martin, Laura B; Micoli, Francesca

    2014-01-01

    Though primarily enteric pathogens, Salmonellae are responsible for a considerable yet under-appreciated global burden of invasive disease. In South and South-East Asia, this manifests as enteric fever caused by serovars Typhi and Paratyphi A. In sub-Saharan Africa, a similar disease burden results from invasive nontyphoidal Salmonellae, principally serovars Typhimurium and Enteritidis. The existing Ty21a live-attenuated and Vi capsular polysaccharide vaccines target S. Typhi and are not effective in young children where the burden of invasive Salmonella disease is highest. After years of lack of investment in new Salmonella vaccines, recent times have seen increased interest in the area led by emerging-market manufacturers, global health vaccine institutes and academic partners. New glycoconjugate vaccines against S. Typhi are becoming available with similar vaccines against other invasive serovars in development. With other new vaccines under investigation, including live-attenuated, protein-based and GMMA vaccines, now is an exciting time for the Salmonella vaccine field. PMID:24804797

  5. Acquiring minimally invasive surgical skills

    NARCIS (Netherlands)

    Hiemstra, Ellen

    2012-01-01

    Many topics in surgical skills education have been implemented without a solid scientific basis. For that reason we have tried to find this scientific basis. We have focused on training and evaluation of minimally invasive surgical skills in a training setting and in practice in the operating room.

  6. Domacios y nectarios extraflorales en Bignoniáceas: componentes vegetales de una interacción mutualística Domatia and extrafloral nectaries in Bignoniaceae: two components of a mutualistic interaction

    Directory of Open Access Journals (Sweden)

    Ana M Gonzalez

    2011-12-01

    Full Text Available Las plantas presentan relaciones mutualísticas con insectos a cambio del control de sus herbívoros u hongos patógenos; por medio de los domacios les ofrecen albergue y mediante la secreción de néctar de nectarios extraflorales les brindan alimento. Se examinó la anatomía foliar en 52 especies de Bignoniaceae con microscopía óptica y electrónica de barrido, con el objetivo de describir los domacios y los nectarios extraflorales. Los domacios presentes son de dos tipos: mechones de pelos y bolsillos, siendo un carácter taxonómico útil en varias especies. Los nectarios extraflorales se encuentran en todas las especies, ubicándose en diversas posiciones: a lo largo de la vena media, asociados a los domacios o agrupados en campos glandulares, que pueden ser foliares o interpeciolares. Las Bignoniaceae presentan simultáneamente domacios y nectarios extraflorales en sus hojas, los cuales se describen como componentes vegetales de un probable mecanismo de defensa indirecta.Plants have mutualistic relationships with insects in two ways: through domatia provide housing of predators, and extrafloral nectaries secreting nectar and provide food in exchange for control of herbivores or fungal pathogens. The foliar anatomy of 52 species of Bignoniaceae was examined by light and scanning electron microscopy, in order to describe the different types of domatia and extrafloral nectaries. Two types of domatia were observed: small hair-tufts and pockets; the presence and type of domatia represents important taxonomic characters in Bignoniaceae. Extrafloral nectaries are found in all studied species. They are located in different positions: along the midvein, associated with domatia, or grouped in glandular fields, either in leaf or interpetiolar. The Bignoniaceae have simultaneously domatia and extrafloral nectaries on their leaves, these features are described as plant components in a probable mechanism of indirect defense.

  7. Were Viking Dry-dock methods in the Americas used earlier to Build Pyramids, with Outflow Eroding the Sphinx, and were Stonehenge, the Obelisks, and Moas Similarly Erected?

    Science.gov (United States)

    McLeod, Edward; McLeod, Roger

    2006-03-01

    Chisel-quarried recycled granite in MA is datable by runes to 1069 CE; it could corroborate dating by a LIDAR. Associated sites, possibly used by Vikings to dry-dock their ships, could have exploited lock-like controls, possibly a continued technology. Site-leveling at the Giza Pyramids proves water was used. `Locks' and body-immersion worked for building, moving, erecting, or watering, at sites like Stonehenge, The Hanging Gardens at Babylon, the Moas of Easter Island, or The Pyramids, where the eroding water discharge was deliberately flushed over the Sphinx complex. It enhance the electromagnetically excited blue light signals we can detect, especially at sites frequented by Molocket of ME. Information, as at America's Stonehenge, in NH, and constructions at Acton MA, at Giza or at Rumford ME proves that the Pyramids and Sphinx were engineered and built about 4500 BP.

  8. 76 FR 68776 - Invasive Species Advisory Committee

    Science.gov (United States)

    2011-11-07

    ... broad array of issues related to preventing the introduction of invasive species and providing for their...-2012 Invasive Species National Management Plan. The meeting is open to the public. An orientation...

  9. 77 FR 23740 - Invasive Species Advisory Committee

    Science.gov (United States)

    2012-04-20

    ... broad array of issues related to preventing the introduction of invasive species and providing for their... both ecological and management contexts, will center on topics that: (1) Pertain to invasive species...

  10. CHUVAS, EROSIVIDADE, ERODIBILIDADE, USO DO SOLO E SUAS RELAÇÕES COM FOCOS EROSIVOS LINEARES NA ALTA BACIA DO RIO ARAGUAIA / Rainfall, erosivity, erodibility, land use and their relationships with erosion sites in the upper Araguaia River Basin

    Directory of Open Access Journals (Sweden)

    Silvando Carlos da Silva

    2007-12-01

    Full Text Available The intensive process of land occupation by farmers in the tropical savanna region of MidwestBrazil during the last three decades has promoted several environment impacts, such as theoccurrence of gully erosion processes as a consequence of intensive deforestation. Just in theUpper Araguaia River Basin, it was identified more than 300 large and medium gully features,which are related with the high natural susceptibility of the sandy soils; high erosivity and erodibility; inadequate land-use; lack of soil conservation practices; and a high annual rainfallindex during the rainy season. The objective of this research was to identify spatial relationshipsbetween rainfall distribution, erosivity, erodibility, land-use, and gully erosion distribution,which may support environmental planning actions related to land use conservation.Quantitative results show a high correlation between gully erosion distribution and higherosivity/erodibility and inadequate land-use.

  11. Restoration of eroded soil in the Sonoran Desert with native leguminous trees using plant growth-promoting microorganisms and limited amounts of compost and water.

    Science.gov (United States)

    Bashan, Yoav; Salazar, Bernardo G; Moreno, Manuel; Lopez, Blanca R; Linderman, Robert G

    2012-07-15

    Restoration of highly eroded desert land was attempted in the southern Sonoran Desert that had lost its natural capacity for self-revegetation. In six field experiments, the fields were planted with three native leguminous trees: mesquite amargo Prosopis articulata, and yellow and blue palo verde Parkinsonia microphylla and Parkinsonia florida. Restoration included inoculation with two of plant growth-promoting bacteria (PGPB; Azospirillum brasilense and Bacillus pumilus), native arbuscular mycorrhizal (AM) fungi, and small quantities of compost. Irrigation was applied, when necessary, to reach a rainy year (300 mm) of the area. The plots were maintained for 61 months. Survival of the trees was marginally affected by all supplements after 30 months, in the range of 60-90%. This variation depended on the plant species, where all young trees were established after 3 months. Plant density was a crucial variable and, in general, low plant density enhanced survival. High planting density was detrimental. Survival significantly declined in trees 61 months after planting. No general response of the trees to plant growth-promoting microorganisms and compost was found. Mesquite amargo and yellow palo verde responded well (height, number of branches, and diameter of the main stem) to inoculation with PGPB, AM fungi, and compost supplementation after three months of application. Fewer positive effects were recorded after 30 months. Blue palo verde did not respond to most treatments and had the lowest survival. Specific plant growth parameters were affected to varying degrees to inoculations or amendments, primarily depending on the tree species. Some combinations of tree/inoculant/amendment resulted in small negative effects or no response when measured after extended periods of time. Using native leguminous trees, this study demonstrated that restoration of severely eroded desert lands was possible. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. EROD activity, chromosomal damage, and oxidative stress in response to contaminants exposure in tree swallow (Tachycineta bicolor) nestlings from Great Lakes Areas of Concern

    Science.gov (United States)

    Custer, Thomas W.; Custer, Christine M.; Dummer, Paul; Bigorgne, Emilie; Oziolor, Elias; Karouna-Renier, Natalie K.; Schultz, Sandra; Erickson, Richard A.; Aagaard, Kevin; Matson, Cole W.

    2017-01-01

    Tree swallow, Tachycineta bicolor, nestlings were collected from 60 sites in the Great Lakes, which included multiple sites within 27 Areas of Concern (AOCs) and six sites not listed as AOCs from 2010 to 2014. Nestlings, approximately 12 days-of-age, were evaluated for ethoxyresorufin-O-dealkylase (EROD) activity, chromosomal damage, and six measures of oxidative stress. Data on each of these biomarkers were divided into four equal numbered groups from the highest to lowest values and the groups were compared to contaminant concentrations using multivariate analysis. Contaminant concentrations, from the same nestlings, included polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), perfluorinated compounds (PFCs), and 17 elements. Alkylated polycyclic aromatic hydrocarbons (aPAHs) and parent PAHs (pPAHs) were measured in pooled nestling dietary samples. Polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and pesticides were measured in sibling eggs. Concentrations of aPAHs, pPAHs, chlordane, dieldrin, heptachlor, and PCBs, in that order, were the major contributors to the significant differences between the lowest and highest EROD activities; PFCs, PBDEs, the remaining pesticides, and all elements were of secondary importance. The four categories of chromosomal damage did not separate out well based on the contaminants measured. Concentrations of aPAHs, pPAHs, heptachlor, PCBs, chlordane, and dieldrin were the major contributors to the significant differences between the lowest and highest activities of two oxidative stress measures, total sulfhydryl (TSH) activity and protein bound sulfhydryl (PBSH) activity. The four categories of thiobarbituric acid reacting substances (TBARS), oxidized glutathione (GSSG), reduced glutathione (GSH), and the ratio of GSSG/GSH did not separate well based on the contaminants measured.

  13. Surface remineralization potential of casein phosphopeptide-amorphous calcium phosphate on enamel eroded by cola-drinks: An in-situ model study

    Directory of Open Access Journals (Sweden)

    Navneet Grewal

    2013-01-01

    Full Text Available Aim: The aim of this study was to investigate the remineralization potential of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP on enamel eroded by cola drinks. Subjects and Methods: A total of 30 healthy subjects were selected from a random sample of 1200 children and divided into two groups of 15 each wherein calcium and phosphorus analyses and scanning electron microscope (SEM analysis was carried out to investigate the remineralization of enamel surface. A total of 30 non-carious premolar teeth were selected from the human tooth bank (HTB to prepare the in-situ appliance. Three enamel slabs were prepared from the same. One enamel slab was used to obtain baseline values and the other two were embedded into the upper palatal appliances prepared on the subjects′ maxillary working model. The subjects wore the appliance after which 30 ml cola drink exposure was given. After 15 days, the slabs were removed and subjected to respective analysis. Statistical Analysis Used: Means of all the readings of soluble calcium and phosphorous levels at baseline,post cola-drink exposure and post cpp-acp application were subjected to statistical analysis SPSS11.5 version.Comparison within groups and between groups was carried out using ANOVA and F-values at 1% level of significance. Results: Decrease in calcium solubility of enamel in the CPP-ACP application group as compared to post-cola drink exposure group (P < 0.05 was seen. Distinctive change in surface topography of enamel in the post-CPP-ACP application group as compared to post-cola drink exposure group was observed. Conclusion: CPP-ACP significantly promoted remineralization of enamel eroded by cola drinks as revealed by significant morphological changes seen in SEM magnification and spectrophotometric analyses.

  14. Invasive plants in 21st Century landscapes.

    Science.gov (United States)

    Valerie. Rapp

    2005-01-01

    A plant species is defined as invasive if it is nonnative to the ecosystem under consideration, and if it causes or is likely to cause economic or environmental harm or harm to human health. Nonnative plant invasions are generally considered to have reached the Pacific Northwest in the mid-1800s with the arrival of European-American settlers. Invasive species such as...

  15. 75 FR 29359 - Invasive Species Advisory Committee

    Science.gov (United States)

    2010-05-25

    ... Council is co-chaired by the Secretary of the Interior, the Secretary of Agriculture, and the Secretary of... of the most invaded marine/coastal environments in the world, with over 50 invasive species that... development of state invasive species councils. DATES: Meeting of the Invasive Species Advisory Committee...

  16. CONSERVATION PROGRAMS THAT PROMOTE INVASIVE SPECIES

    Science.gov (United States)

    Invasive plant species are degrading the structure and function of ecosystems throughout the world. Although most state and federal conservation agencies in the U.S. attempt to reduce the impact of invasive species, some agency activities can contribute to the spread of invasive...

  17. Invasive Species Science Update (No. 7)

    Science.gov (United States)

    Dean Pearson; Yvette Ortega; Jack Butler

    2014-01-01

    Invasive Species Science Updates are designed to keep managers and other users up-to-date with recently completed and ongoing research by RMRS scientists, as well as highlight breaking news related to invasive species issues. The newsletter is produced by the RMRS Invasive Species Working Group (ISWG), which is a core group of scientists who volunteer to coordinate...

  18. Invasive Plants on Rangelands: a Global Threat

    Science.gov (United States)

    Invasive plant species are spreading and invading rangelands at an unprecedented rate costing ranchers billions of dollars to control invasive plants each year. In its simplest form, the invasion process has four primary stages, including introduction, establishment, spread and colonization. Th...

  19. Do invasive plant species alter soil health?

    Science.gov (United States)

    Invasive species may alter soil characteristics or interact with the soil microbial community to yield a competitive advantage. Our objectives were to determine: if invasive plant species alter soil properties important to soil health; and the long-term effects of invasive plant species on soil pro...

  20. Invasive plant species in hardwood tree plantations

    Science.gov (United States)

    Rochelle R. Beasley; Paula M. Pijut

    2010-01-01

    Invasive plants are species that can grow and spread aggressively, mature quickly, and invade an ecosystem causing economic and environmental damage. Invasive plants usually invade disturbed areas, but can also colonize small areas quickly, and may spread and dominate large areas in a few short years. Invasive plant species displace native or desirable forest...

  1. Terrestrial animals as invasive species and as species at risk from invasions

    Science.gov (United States)

    Deborah M. Finch; Dean Pearson; Joseph Wunderle; Wayne Arendt

    2010-01-01

    Including terrestrial animal species in the invasive species strategy plan is an important step in invasive species management. Invasions by nonindigenous species threaten nearly 50 percent of imperiled native species in the United States and are the Nation's second leading cause of species endangerment. Invasion and conversion of native habitats by exotic species...

  2. The risk of establishment of aquatic invasive species: joining invasibility and propagule pressure.

    Science.gov (United States)

    Leung, Brian; Mandrak, Nicholas E

    2007-10-22

    Invasive species are increasingly becoming a policy priority. This has spurred researchers and managers to try to estimate the risk of invasion. Conceptually, invasions are dependent both on the receiving environment (invasibility) and on the ability to reach these new areas (propagule pressure). However, analyses of risk typically examine only one or the other. Here, we develop and apply a joint model of invasion risk that simultaneously incorporates invasibility and propagule pressure. We present arguments that the behaviour of these two elements of risk differs substantially--propagule pressure is a function of time, whereas invasibility is not--and therefore have different management implications. Further, we use the well-studied zebra mussel (Dreissena polymorpha) to contrast predictions made using the joint model to those made by separate invasibility and propagule pressure models. We show that predictions of invasion progress as well as of the long-term invasion pattern are strongly affected by using a joint model.

  3. Radiologic aspects in invasive aspergillosis

    International Nuclear Information System (INIS)

    Feger, C.; Kerviler, E. de; Zagdanski, A.M.; Attal, P.; Cyna-Gorse, F.; Frija, J.; Laval-Jeantet, M.

    1994-01-01

    Invasive aspergillosis is a life-threatening illness, whose diagnosis is difficult: clinical signs are indeed not specific, and biological and mycological exams are not always conclusive. Radiological exams are essential for the diagnosis of this disease allowing to start an early intensive appropriate therapy. According to the literature and to their own experience the authors report the main radiological patterns with emphasis on the pulmonary and cerebral affections. (authors). 26 refs., 5 figs

  4. [Minimally invasive coronary artery surgery].

    Science.gov (United States)

    Zalaquett, R; Howard, M; Irarrázaval, M J; Morán, S; Maturana, G; Becker, P; Medel, J; Sacco, C; Lema, G; Canessa, R; Cruz, F

    1999-01-01

    There is a growing interest to perform a left internal mammary artery (LIMA) graft to the left anterior descending coronary artery (LAD) on a beating heart through a minimally invasive access to the chest cavity. To report the experience with minimally invasive coronary artery surgery. Analysis of 11 patients aged 48 to 79 years old with single vessel disease that, between 1996 and 1997, had a LIMA graft to the LAD performed through a minimally invasive left anterior mediastinotomy, without cardiopulmonary bypass. A 6 to 10 cm left parasternal incision was done. The LIMA to the LAD anastomosis was done after pharmacological heart rate and blood pressure control and a period of ischemic pre conditioning. Graft patency was confirmed intraoperatively by standard Doppler techniques. Patients were followed for a mean of 11.6 months (7-15 months). All patients were extubated in the operating room and transferred out of the intensive care unit on the next morning. Seven patients were discharged on the third postoperative day. Duplex scanning confirmed graft patency in all patients before discharge; in two patients, it was confirmed additionally by arteriography. There was no hospital mortality, no perioperative myocardial infarction and no bleeding problems. After follow up, ten patients were free of angina, in functional class I and pleased with the surgical and cosmetic results. One patient developed atypical angina on the seventh postoperative month and a selective arteriography confirmed stenosis of the anastomosis. A successful angioplasty of the original LAD lesion was carried out. A minimally invasive left anterior mediastinotomy is a good surgical access to perform a successful LIMA to LAD graft without cardiopulmonary bypass, allowing a shorter hospital stay and earlier postoperative recovery. However, a larger experience and a longer follow up is required to define its role in the treatment of coronary artery disease.

  5. Acquiring minimally invasive surgical skills

    OpenAIRE

    Hiemstra, Ellen

    2012-01-01

    Many topics in surgical skills education have been implemented without a solid scientific basis. For that reason we have tried to find this scientific basis. We have focused on training and evaluation of minimally invasive surgical skills in a training setting and in practice in the operating room. This thesis has led to an enlarged insight in the organization of surgical skills training during residency training of surgical medical specialists.

  6. Biological invasions, ecological resilience and adaptive governance.

    Science.gov (United States)

    Chaffin, Brian C; Garmestani, Ahjond S; Angeler, David G; Herrmann, Dustin L; Stow, Craig A; Nyström, Magnus; Sendzimir, Jan; Hopton, Matthew E; Kolasa, Jurek; Allen, Craig R

    2016-12-01

    In a world of increasing interconnections in global trade as well as rapid change in climate and land cover, the accelerating introduction and spread of invasive species is a critical concern due to associated negative social and ecological impacts, both real and perceived. Much of the societal response to invasive species to date has been associated with negative economic consequences of invasions. This response has shaped a war-like approach to addressing invasions, one with an agenda of eradications and intense ecological restoration efforts towards prior or more desirable ecological regimes. This trajectory often ignores the concept of ecological resilience and associated approaches of resilience-based governance. We argue that the relationship between ecological resilience and invasive species has been understudied to the detriment of attempts to govern invasions, and that most management actions fail, primarily because they do not incorporate adaptive, learning-based approaches. Invasive species can decrease resilience by reducing the biodiversity that underpins ecological functions and processes, making ecosystems more prone to regime shifts. However, invasions do not always result in a shift to an alternative regime; invasions can also increase resilience by introducing novelty, replacing lost ecological functions or adding redundancy that strengthens already existing structures and processes in an ecosystem. This paper examines the potential impacts of species invasions on the resilience of ecosystems and suggests that resilience-based approaches can inform policy by linking the governance of biological invasions to the negotiation of tradeoffs between ecosystem services. Copyright © 2016. Published by Elsevier Ltd.

  7. Invasive Paget Disease of the Vulva.

    Science.gov (United States)

    Borghi, Chiara; Bogani, Giorgio; Ditto, Antonino; Martinelli, Fabio; Signorelli, Mauro; Chiappa, Valentina; Scaffa, Cono; Perotto, Stefania; Leone Roberti Maggiore, Umberto; Recalcati, Dario; Lorusso, Domenica; Raspagliesi, Francesco

    2018-01-01

    Extramammary Paget disease of the vulva (EPDV) is a rare occurrence with an indolent and relapsing course. Progression to invasion occurs in 4% to 19% of cases. The aim of this study is to report clinical-pathological features and outcomes of patients treated for invasive EPDV. Data of consecutive patients treated between 2000 and 2017 for invasive EPDV were reviewed. Among 79 patients with EPDV, 10 (12.7%) presented a microinvasive or invasive form at first diagnosis or during follow-up. All of them underwent upfront radical surgery; 7 (70%) received subsequent radiotherapy, chemotherapy, or both. The mortality rate was 40%. The recurrence rate after treatment for invasive forms was 60%, with a mean time to first recurrence of 20 (range, 5-36) months. Our study confirms that invasive EPDV remains a rare gynecological neoplasm with a poor prognosis. Multicentre trials or well-organized prospective data collection could improve the knowledge about the management of invasive EPDV.

  8. Invasive predators and global biodiversity loss.

    Science.gov (United States)

    Doherty, Tim S; Glen, Alistair S; Nimmo, Dale G; Ritchie, Euan G; Dickman, Chris R

    2016-10-04

    Invasive species threaten biodiversity globally, and invasive mammalian predators are particularly damaging, having contributed to considerable species decline and extinction. We provide a global metaanalysis of these impacts and reveal their full extent. Invasive predators are implicated in 87 bird, 45 mammal, and 10 reptile species extinctions-58% of these groups' contemporary extinctions worldwide. These figures are likely underestimated because 23 critically endangered species that we assessed are classed as "possibly extinct." Invasive mammalian predators endanger a further 596 species at risk of extinction, with cats, rodents, dogs, and pigs threatening the most species overall. Species most at risk from predators have high evolutionary distinctiveness and inhabit insular environments. Invasive mammalian predators are therefore important drivers of irreversible loss of phylogenetic diversity worldwide. That most impacted species are insular indicates that management of invasive predators on islands should be a global conservation priority. Understanding and mitigating the impact of invasive mammalian predators is essential for reducing the rate of global biodiversity loss.

  9. 3D-CRT, Proton, or Brachytherapy APBI in Treating Patients With Invasive and Non-invasive Breast Cancer

    Science.gov (United States)

    2017-12-29

    Ductal Breast Carcinoma In Situ; Estrogen Receptor Positive; Grade 1 Invasive Breast Carcinoma; Grade 2 Invasive Breast Carcinoma; Grade 3 Invasive Breast Carcinoma; Invasive Ductal and Lobular Carcinoma In Situ; Mucinous Breast Carcinoma; Tubular Breast Carcinoma

  10. Invasive ductal carcinoma vs. invasive lobular carcinoma; mammographic findings

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Chun; Do, Young Soo; Oh, Hoon Il; Han, Yoon Hee; Kim, Ki Soo; Chin, Soo Yil [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

    1996-01-01

    The purpose of this study is to evaluate mammographic findings of invasive ductal carcinoma (IDC) and invasive lobular carcinoma(ILC) and to find differential points between the two. 239 patients, who underwent mammography prior to surgery and were proved to have IDC(patients) or ILC(15 patients) pathologically, were analized retrospectively. On mammogram, presence of mass and microcalcification were analized. When there was a mass on mammogram, lesion opacity was classified into high, equal, or low opacity and border of the mass was classified into spiculated, poorly marginated, and well-marginated. When there was no definite mass, mammographic findings were classifie into asymmetric opacity and no mass. Masses were observed in 168 patients(75%) of IDC and 12 patients(80%) of ILC. Border of the masses were spiculated(n=50, 22.3%), poorly marginated(n=112, 50%), or well-marginated(n=6, 2.7%) in patients with IDC. Spiculated and poorly marginated borders were observed in 8 patients(53.3%) and 4 patients(26.7%) respectively, in patients with ILC. Microcalcifications were seen in 88 patients(17.3%) of IDC and patients(33.3%) of ILC. Although equal or low opacities were observed more frequently in ILC and microcalcifications were noted more frequently in IDC, it was difficult to differentiate the two diseases based on mammographic findings.

  11. Invasive ductal carcinoma vs. invasive lobular carcinoma; mammographic findings

    International Nuclear Information System (INIS)

    Lee, Eun Chun; Do, Young Soo; Oh, Hoon Il; Han, Yoon Hee; Kim, Ki Soo; Chin, Soo Yil

    1996-01-01

    The purpose of this study is to evaluate mammographic findings of invasive ductal carcinoma (IDC) and invasive lobular carcinoma(ILC) and to find differential points between the two. 239 patients, who underwent mammography prior to surgery and were proved to have IDC(patients) or ILC(15 patients) pathologically, were analized retrospectively. On mammogram, presence of mass and microcalcification were analized. When there was a mass on mammogram, lesion opacity was classified into high, equal, or low opacity and border of the mass was classified into spiculated, poorly marginated, and well-marginated. When there was no definite mass, mammographic findings were classifie into asymmetric opacity and no mass. Masses were observed in 168 patients(75%) of IDC and 12 patients(80%) of ILC. Border of the masses were spiculated(n=50, 22.3%), poorly marginated(n=112, 50%), or well-marginated(n=6, 2.7%) in patients with IDC. Spiculated and poorly marginated borders were observed in 8 patients(53.3%) and 4 patients(26.7%) respectively, in patients with ILC. Microcalcifications were seen in 88 patients(17.3%) of IDC and patients(33.3%) of ILC. Although equal or low opacities were observed more frequently in ILC and microcalcifications were noted more frequently in IDC, it was difficult to differentiate the two diseases based on mammographic findings

  12. Non-invasive neural stimulation

    Science.gov (United States)

    Tyler, William J.; Sanguinetti, Joseph L.; Fini, Maria; Hool, Nicholas

    2017-05-01

    Neurotechnologies for non-invasively interfacing with neural circuits have been evolving from those capable of sensing neural activity to those capable of restoring and enhancing human brain function. Generally referred to as non-invasive neural stimulation (NINS) methods, these neuromodulation approaches rely on electrical, magnetic, photonic, and acoustic or ultrasonic energy to influence nervous system activity, brain function, and behavior. Evidence that has been surmounting for decades shows that advanced neural engineering of NINS technologies will indeed transform the way humans treat diseases, interact with information, communicate, and learn. The physics underlying the ability of various NINS methods to modulate nervous system activity can be quite different from one another depending on the energy modality used as we briefly discuss. For members of commercial and defense industry sectors that have not traditionally engaged in neuroscience research and development, the science, engineering and technology required to advance NINS methods beyond the state-of-the-art presents tremendous opportunities. Within the past few years alone there have been large increases in global investments made by federal agencies, foundations, private investors and multinational corporations to develop advanced applications of NINS technologies. Driven by these efforts NINS methods and devices have recently been introduced to mass markets via the consumer electronics industry. Further, NINS continues to be explored in a growing number of defense applications focused on enhancing human dimensions. The present paper provides a brief introduction to the field of non-invasive neural stimulation by highlighting some of the more common methods in use or under current development today.

  13. Antarctic crabs: invasion or endurance?

    Directory of Open Access Journals (Sweden)

    Huw J Griffiths

    Full Text Available Recent scientific interest following the "discovery" of lithodid crabs around Antarctica has centred on a hypothesis that these crabs might be poised to invade the Antarctic shelf if the recent warming trend continues, potentially decimating its native fauna. This "invasion hypothesis" suggests that decapod crabs were driven out of Antarctica 40-15 million years ago and are only now returning as "warm" enough habitats become available. The hypothesis is based on a geographically and spatially poor fossil record of a different group of crabs (Brachyura, and examination of relatively few Recent lithodid samples from the Antarctic slope. In this paper, we examine the existing lithodid fossil record and present the distribution and biogeographic patterns derived from over 16,000 records of Recent Southern Hemisphere crabs and lobsters. Globally, the lithodid fossil record consists of only two known specimens, neither of which comes from the Antarctic. Recent records show that 22 species of crabs and lobsters have been reported from the Southern Ocean, with 12 species found south of 60 °S. All are restricted to waters warmer than 0 °C, with their Antarctic distribution limited to the areas of seafloor dominated by Circumpolar Deep Water (CDW. Currently, CDW extends further and shallower onto the West Antarctic shelf than the known distribution ranges of most lithodid species examined. Geological evidence suggests that West Antarctic shelf could have been available for colonisation during the last 9,000 years. Distribution patterns, species richness, and levels of endemism all suggest that, rather than becoming extinct and recently re-invading from outside Antarctica, the lithodid crabs have likely persisted, and even radiated, on or near to Antarctic slope. We conclude there is no evidence for a modern-day "crab invasion". We recommend a repeated targeted lithodid sampling program along the West Antarctic shelf to fully test the validity of the

  14. The Invasive Species Forecasting System

    Science.gov (United States)

    Schnase, John; Most, Neal; Gill, Roger; Ma, Peter

    2011-01-01

    The Invasive Species Forecasting System (ISFS) provides computational support for the generic work processes found in many regional-scale ecosystem modeling applications. Decision support tools built using ISFS allow a user to load point occurrence field sample data for a plant species of interest and quickly generate habitat suitability maps for geographic regions of management concern, such as a national park, monument, forest, or refuge. This type of decision product helps resource managers plan invasive species protection, monitoring, and control strategies for the lands they manage. Until now, scientists and resource managers have lacked the data-assembly and computing capabilities to produce these maps quickly and cost efficiently. ISFS focuses on regional-scale habitat suitability modeling for invasive terrestrial plants. ISFS s component architecture emphasizes simplicity and adaptability. Its core services can be easily adapted to produce model-based decision support tools tailored to particular parks, monuments, forests, refuges, and related management units. ISFS can be used to build standalone run-time tools that require no connection to the Internet, as well as fully Internet-based decision support applications. ISFS provides the core data structures, operating system interfaces, network interfaces, and inter-component constraints comprising the canonical workflow for habitat suitability modeling. The predictors, analysis methods, and geographic extents involved in any particular model run are elements of the user space and arbitrarily configurable by the user. ISFS provides small, lightweight, readily hardened core components of general utility. These components can be adapted to unanticipated uses, are tailorable, and require at most a loosely coupled, nonproprietary connection to the Web. Users can invoke capabilities from a command line; programmers can integrate ISFS's core components into more complex systems and services. Taken together, these

  15. [Minimally invasive approach for cervical spondylotic radiculopathy].

    Science.gov (United States)

    Ding, Liang; Sun, Taicun; Huang, Yonghui

    2010-01-01

    To summarize the recent minimally invasive approach for cervical spondylotic radiculopathy (CSR). The recent literature at home and abroad concerning minimally invasive approach for CSR was reviewed and summarized. There were two techniques of minimally invasive approach for CSR at present: percutaneous puncture techniques and endoscopic techniques. The degenerate intervertebral disc was resected or nucleolysis by percutaneous puncture technique if CSR was caused by mild or moderate intervertebral disc herniations. The cervical microendoscopic discectomy and foraminotomy was an effective minimally invasive approach which could provide a clear view. The endoscopy techniques were suitable to treat CSR caused by foraminal osteophytes, lateral disc herniations, local ligamentum flavum thickening and spondylotic foraminal stenosis. The minimally invasive procedure has the advantages of simple handling, minimally invasive and low incidence of complications. But the scope of indications is relatively narrow at present.

  16. [Iron and invasive fungal infection].

    Science.gov (United States)

    Álvarez, Florencio; Fernández-Ruiz, Mario; Aguado, José María

    2013-01-01

    Iron is an essential factor for both the growth and virulence of most of microorganisms. As a part of the innate (or nutritional) immune system, mammals have developed different mechanisms to store and transport this element in order to limit free iron bioavailability. To survive in this hostile environment, pathogenic fungi have specific uptake systems for host iron sources, one of the most important of which is based on the synthesis of siderophores-soluble, low-molecular-mass, high-affinity iron chelators. The increase in free iron that results from iron-overload conditions is a well-established risk factor for invasive fungal infection (IFI) such as mucormycosis or aspergillosis. Therefore, iron chelation may be an appealing therapeutic option for these infections. Nevertheless, deferoxamine -the first approved iron chelator- paradoxically increases the incidence of IFI, as it serves as a xeno-siderophore to Mucorales. On the contrary, the new oral iron chelators (deferiprone and deferasirox) have shown to exert a deleterious effect on fungal growth both in vitro and in animal models. The present review focuses on the role of iron metabolism in the pathogenesis of IFI and summarises the preclinical data, as well as the limited clinical experience so far, in the use of new iron chelators as treatment for mucormycosis and invasive aspergillosis. Copyright © 2012 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

  17. Soil Erodibility under Natural Rainfall Conditions as the K Factor of the Universal Soil Loss Equation and Application of the Nomograph for a Subtropical Ultisol

    Directory of Open Access Journals (Sweden)

    Elemar Antonino Cassol

    2018-05-01

    Full Text Available ABSTRACT: Erodibility represents the intrinsic susceptibility of the soil to the erosion process, represented by the K factor in the Universal Soil Loss Equation (USLE. In Brazil, there are few field experiments determined with a series larger than ten years of data, which are the most reliable for quantifying the K factor. The aim of this study was to determine the K factor of the USLE by the direct method, relating soil losses determined in the field under standard conditions to erosivity of rains, and by the analytic method, applying the Wischmeier nomograph. The data on soil loss by water erosion were obtained in a field experiment under natural rainfall conditions from 1976 to 1989 in an Ultisol at the Agronomic Experimental Station in Eldorado do Sul, RS, Brazil. The value of the K factor by the direct method was 0.0338 Mg ha h ha-1 MJ-1 mm-1, which is high, showing considerable susceptibility of the soil to erosion. From the analytical method, the K factor obtained was 0.0325 Mg ha h ha-1 MJ-1 mm-1, a value very close to that determined experimentally. Thus, the Wischmeier nomograph proved to be valid for determination of the K factor of the Ultisol under study. This method proved to be valid for this type of soil. These results can be used for calibration models based on the USLE.

  18. Invasion ecology meets parasitology: Advances and challenges

    OpenAIRE

    Robert Poulin

    2017-01-01

    Biological invasions threaten the diversity and functioning of native ecosystems, and the rate at which species are being introduced to new areas shows no sign of slowing down. Parasites play roles in biological invasions, for instance when native parasites interact with exotic hosts, or when parasites themselves are introduced to new areas. However, publication trends show clearly that research on parasitism in the context of biological invasions is lagging far behind research on biological ...

  19. Invasive Species Science Update (No. 10)

    Science.gov (United States)

    Justin Runyon

    2018-01-01

    In this issue, we cover new research on wide-ranging topics from the longterm effects of drought on competition between native and invasive plant species, to the effects of drought on pollinator visitation to invasive plants, to a novel use of insect pheromones to improve biocontrol of invasive saltcedar. There’s also big news to report in weed biocontrol: two new...

  20. Invasion ecology meets parasitology: Advances and challenges

    Directory of Open Access Journals (Sweden)

    Robert Poulin

    2017-12-01

    Full Text Available Biological invasions threaten the diversity and functioning of native ecosystems, and the rate at which species are being introduced to new areas shows no sign of slowing down. Parasites play roles in biological invasions, for instance when native parasites interact with exotic hosts, or when parasites themselves are introduced to new areas. However, publication trends show clearly that research on parasitism in the context of biological invasions is lagging far behind research on biological invasions in general. The different articles in this special issue of International Journal for Parasitology–Parasites and Wildlife on ‘Invasions’ address various aspects of the interface between parasitology and invasion biology, including how invasive free-living species lose or gain parasites on the invasion front as they move away from their site of introduction, how these invasive species affect the dynamics of native parasites, and how exotic parasites become established and impact native hosts. Together, they highlight the challenges facing researchers in this area, and set the agenda for the next few years of research. Keywords: alien species, Biological invasions, Enemy release, Non-natives, Parasites

  1. Microparasites and Placental Invasiveness in Eutherian Mammals.

    Directory of Open Access Journals (Sweden)

    Isabella Capellini

    Full Text Available Placental invasiveness-the number of maternal tissue layers separating fetal tissues from maternal blood-is variable across mammalian species. Although this diversity is likely to be functionally important, variation in placental invasiveness remains unexplained. Here we test the hypothesis that increased risk of transplacental transmission of pathogens from the mother to the fetus promotes the evolution of non-invasive placentation, the most likely derived condition in eutherian mammals. Specifically, we predict that non-invasive placentation is associated with increased microparasite species richness relative to more invasive placental types, based on the assumption that higher numbers of microparasites in a population reflects greater risk of transplacental transmission to fetuses. As predicted, higher bacteria species richness is associated with non-invasive placentation. Protozoa species richness, however, shows the opposite pattern. Because invasive placentae facilitate the transfer of maternal antibodies to the fetus, we propose that the ancestral condition of invasive placentation is retained under selection for protection of newborns from higher risk of postnatal protozoan infection. Hence, our findings suggest that a tradeoff exists between protection against bacterial infection prenatally and protozoan infection postnatally. Future studies are needed to investigate how maternal prevalence of infection and the relative pre- versus postnatal risk of fetal infection by different microparasite groups vary among mammalian hosts in relation to placental invasiveness.

  2. Intraspecies differenes in phenotypic plasticity: Invasive versus non-invasive populations of Ceratophyllum demersum

    DEFF Research Database (Denmark)

    Hyldgaard, Benita; Brix, Hans

    2012-01-01

    High phenotypic plasticity has been hypothesized to affect the invasiveness of plants, as high plasticity may enlarge the breath of environments in which the plants can survive and reproduce. Here we compare the phenotypic plasticity of invasive and non-invasive populations of the same species...... hypothesized that the phenotypic plasticity in fitness-related traits like growth and photosynthesis were higher in the invasive than in the non-invasive population. The invasive population acclimated to elevated temperatures through increased rates of photosynthesis (range: Pamb: 8–452 mol O2 g−1 DM h−1......-harvesting complex. Hence, the invasive population of C. demersum from New Zealand had higher phenotypic plasticity in response to temperature than the non-invasive Danish population. This might be the result of genetic evolution since its introduction to New Zealand five decades ago, but further studies are needed...

  3. An Evolutionary Modelling Approach To Understanding The Factors Behind Plant Invasiveness And Community Susceptibility To Invasion

    DEFF Research Database (Denmark)

    Warren, John; Topping, Christopher John; James, Penri

    2011-01-01

    Ecologists have had limited success in understanding which introduced species may become invasive. An evolutionary model is used to investigate which traits are associated with invasiveness. Translocation experiments were simulated in which species were moved into similar but evolutionary younger...

  4. Invasion of a mined landscape: what habitat characteristics are influencing the occurrence of invasive plants?

    Science.gov (United States)

    D. Lemke; I.A. Tazisong; Y. Wang; J.A. Brown

    2012-01-01

    Throughout the world, the invasion of alien plants is an increasing threat to native biodiversity. Invasion is especially prevalent in areas affected by land transformation and anthropogenic disturbance. Surface mines are a major disturbance, and thus may promote the establishment and expansion of invasive plant communities. Environmental and habitat factors that may...

  5. Comparative anatomy of invasive and non-invasive species in the ...

    African Journals Online (AJOL)

    The foliar and stem micromorphological study of the invasive and non-invasive species were undertaken using Light Microscope (LM). The occurrence of vessels in the pillar of the abundant sclerenchyma tissues are important component of the skeletal system in the invasive species. The prominent tiles of parenchymatous ...

  6. E-commerce trade in invasive plants.

    Science.gov (United States)

    Humair, Franziska; Humair, Luc; Kuhn, Fabian; Kueffer, Christoph

    2015-12-01

    Biological invasions are a major concern in conservation, especially because global transport of species is still increasing rapidly. Conservationists hope to anticipate and thus prevent future invasions by identifying and regulating potentially invasive species through species risk assessments and international trade regulations. Among many introduction pathways of non-native species, horticulture is a particularly important driver of plant invasions. In recent decades, the horticultural industry expanded globally and changed structurally through the emergence of new distribution channels, including internet trade (e-commerce). Using an automated search algorithm, we surveyed, on a daily basis, e-commerce trade on 10 major online auction sites (including eBay) of approximately three-fifths of the world's spermatophyte flora. Many recognized invasive plant species (>500 species) (i.e., species associated with ecological or socio-economic problems) were traded daily worldwide on the internet. A markedly higher proportion of invasive than non-invasive species were available online. Typically, for a particular plant family, 30-80% of recognized invasive species were detected on an auction site, but only a few percentages of all species in the plant family were detected on a site. Families that were more traded had a higher proportion of invasive species than families that were less traded. For woody species, there was a significant positive relationship between the number of regions where a species was sold and the number of regions where it was invasive. Our results indicate that biosecurity is not effectively regulating online plant trade. In the future, automated monitoring of e-commerce may help prevent the spread of invasive species, provide information on emerging trade connectivity across national borders, and be used in horizon scanning exercises for early detection of new species and their geographic source areas in international trade. © 2015 Society for

  7. Unconventional gas development facilitates plant invasions.

    Science.gov (United States)

    Barlow, Kathryn M; Mortensen, David A; Drohan, Patrick J; Averill, Kristine M

    2017-11-01

    Vegetation removal and soil disturbance from natural resource development, combined with invasive plant propagule pressure, can increase vulnerability to plant invasions. Unconventional oil and gas development produces surface disturbance by way of well pad, road, and pipeline construction, and increased traffic. Little is known about the resulting impacts on plant community assembly, including the spread of invasive plants. Our work was conducted in Pennsylvania forests that overlay the Marcellus and Utica shale formations to determine if invasive plants have spread to edge habitat created by unconventional gas development and to investigate factors associated with their presence. A piecewise structural equation model was used to determine the direct and indirect factors associated with invasive plant establishment on well pads. The model included the following measured or calculated variables: current propagule pressure on local access roads, the spatial extent of the pre-development road network (potential source of invasive propagules), the number of wells per pad (indicator of traffic density), and pad age. Sixty-one percent of the 127 well pads surveyed had at least one invasive plant species present. Invasive plant presence on well pads was positively correlated with local propagule pressure on access roads and indirectly with road density pre-development, the number of wells, and age of the well pad. The vast reserves of unconventional oil and gas are in the early stages of development in the US. Continued development of this underground resource must be paired with careful monitoring and management of surface ecological impacts, including the spread of invasive plants. Prioritizing invasive plant monitoring in unconventional oil and gas development areas with existing roads and multi-well pads could improve early detection and control of invasive plants. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. ENVIRONMENTAL ASSESSMENT OF ERODED SOILS

    Directory of Open Access Journals (Sweden)

    Yolanda Maya

    2010-12-01

    Full Text Available La degradación del suelo causada por erosión hídrica amenaza seriamente la calidad de los recursos de los que depende el hombre para su subsistencia, como el agua, suelos y cultivos. El diagnóstico de los suelos a partir de variables ambientales es indispensable para la planeación e implementación de planes de manejo para el mejoramiento de este recurso. En este trabajo se presenta una revisión de algunas de las herramientas tecnológicas que se utilizan para evaluar la degradación del suelo causada por erosión hídrica a diversas escalas, considerando los factores determinantes en cada nivel. Las escalas analizadas son: agregados superficiales del suelo, parcela o potrero y cuenca hidrológica. Se mencionan en cada caso las variables indicadoras de la erosión, así como los métodos y herramientas que se utilizan para su evaluación. Se presenta un estudio caso.

  9. Minimally invasive aortic valve replacement

    DEFF Research Database (Denmark)

    Foghsgaard, Signe; Schmidt, Thomas Andersen; Kjaergard, Henrik K

    2009-01-01

    In this descriptive prospective study, we evaluate the outcomes of surgery in 98 patients who were scheduled to undergo minimally invasive aortic valve replacement. These patients were compared with a group of 50 patients who underwent scheduled aortic valve replacement through a full sternotomy...... operations were completed as mini-sternotomies, 4 died later of noncardiac causes. The aortic cross-clamp and perfusion times were significantly different across all groups (P replacement...... is an excellent operation in selected patients, but its true advantages over conventional aortic valve replacement (other than a smaller scar) await evaluation by means of randomized clinical trial. The "extended mini-aortic valve replacement" operation, on the other hand, is a risky procedure that should...

  10. A minimally invasive smile enhancement.

    Science.gov (United States)

    Peck, Fred H

    2014-01-01

    Minimally invasive dentistry refers to a wide variety of dental treatments. On the restorative aspect of dental procedures, direct resin bonding can be a very conservative treatment option for the patient. When tooth structure does not need to be removed, the patient benefits. Proper treatment planning is essential to determine how conservative the restorative treatment will be. This article describes the diagnosis, treatment options, and procedural techniques in the restoration of 4 maxillary anterior teeth with direct composite resin. The procedural steps are reviewed with regard to placing the composite and the variety of colors needed to ensure a natural result. Finishing and polishing of the composite are critical to ending with a natural looking dentition that the patient will be pleased with for many years.

  11. Chapter 8: Invasive fungal rhinosinusitis.

    Science.gov (United States)

    Duggal, Praveen; Wise, Sarah K

    2013-01-01

    Invasive fungal rhinosinusitis (IFRS) is a disease of the paranasal sinuses and nasal cavity that typically affects immunocompromised patients in the acute fulminant form. Early symptoms can often mimic rhinosinusitis, while late symptoms can cause significant morbidity and mortality. Swelling and mucosal thickening can quickly progress to pale or necrotic tissue in the nasal cavity and sinuses, and the disease can rapidly spread and invade the palate, orbit, cavernous sinus, cranial nerves, skull base, carotid artery, and brain. IFRS can be life threatening if left undiagnosed or untreated. While the acute fulminant form of IFRS is the most rapidly progressive and destructive, granulomatous and chronic forms also exist. Diagnosis of IFRS often mandates imaging studies in conjunction with clinical, endoscopic, and histopathological examination. Treatment of IFRS consists of reversing the underlying immunosuppression, antifungal therapy, and aggressive surgical debridement. With early diagnosis and treatment, IFRS can be treated and increase patient survival.

  12. Invasive alien birds in Denmark

    DEFF Research Database (Denmark)

    Fox, Anthony David; Heldbjerg, Henning; Nyegaard, Timme

    2015-01-01

    Avian Introduced Alien Species (IAS) constitute a threat to the integrity of native biodiversity, the economy and human health, so here we briefly review some of the problems posed by such species around the world in relation to such bird species in Denmark. A new European Union Regulation...... on Invasive Alien Species implemented in January 2015 establishes a framework for actions to combat alien species, which requires Member States to prevent the spread of alien species, provide early warning and rapid responses to their presence and management of established alien species where they occur. We...... show the importance of mechanisms such as DOF’s (Dansk Ornitologisk Forening, BirdLife Denmark) Atlas project, Common Bird Census (breeding and wintering species) and DOFbasen to contribute data on the current geographical and numerical distribution of the few serious alien avian species already...

  13. Invasive alien birds in Denmark

    DEFF Research Database (Denmark)

    Nyegaard, Timme; Heldbjerg, Henning; Fox, Anthony David

    Avian Introduced Alien Species (IAS) constitute a threat to the integrity of native biodiversity, the economy and human health, so here we briefly review some of the problems posed by such species around the world in relation to bird species in Denmark. A new European Union Regulation on Invasive...... Alien Species implemented in January 2015 requires a framework for actions to combat alien species, which requires Member States to prevent the spread of alien species, provide early warning and rapid responses to their presence and management of established alien species where they occur. We show...... the importance of mechanisms such as DOFs (Danish Ornithological Society, BirdLife Denmark) Atlas project, Common Bird Monitoring (breeding and wintering species) and DOFbasen to contribute data on the current geographical and numerical distribution of the few serious alien avian species already present...

  14. Estimativa da erodibilidade pela desagregação por ultra-som e atributos de solos com horizonte B textural Estimating soil erodibility from sonication indexes and other attributes of textural B horizon soils

    Directory of Open Access Journals (Sweden)

    Marcos Aurélio Carolino de Sá

    2004-07-01

    Full Text Available A erodibilidade de solos é um fator importante na estimativa das perdas por erosão. Este fator é uma expressão da combinação de atributos do solo, os quais possibilitam sua estimativa por meio de equações. O objetivo deste trabalho foi medir atributos químicos e mineralógicos que, combinados com índices de estabilidade de agregados determinados por ultra-som, pudessem ser utilizados como variáveis em modelos na estimativa da erodibilidade de solos com horizonte B textural do Brasil. Estes atributos foram determinados em 22 solos de erodibilidade conhecida, medida diretamente em parcelas no campo. Atributos de 21 dos solos foram utilizados no ajuste dos modelos. Um dos solos (Argissolo Vermelho-Amarelo foi escolhido ao acaso para teste. De 96 variáveis, 15 foram incluídas nos modelos de estimativa da erodibilidade. A maioria delas é representada por índices de desagregação por sonificação de amostras do horizonte A. Foram obtidos quatro modelos para estimar a erodibilidade, com R² variando entre 0,83** e 0,91**. A erodibilidade pode ser estimada com base na estabilidade de agregados por ultra-som.Soil erodibility is an important factor for estimating soil erosion losses. This factor is an expression of combined soil attributes, which make possible its estimation by equations. The objective of this study was to measure some chemical and mineralogical attributes, and to combine them with aggregate stability indexes from sonication analysis, in equations in order to estimate soil erodibility of textural B horizon soils from Brazil. These attributes were measured for 22 soils that had their erodibility measured from field plots. Attributes of 21 soils were used to adjust the equations. One of the soils (Red-Yellow Argisol was used to test the equations. From 96 variables, 15 were significantly correlated to soil erodibility. Most of them are represented by the disruption indexes from sonication analysis of A horizon samples. This

  15. Invasion of erythrocytes by Babesia bovis

    NARCIS (Netherlands)

    Gaffar, Fasila Razzia

    2004-01-01

    In this thesis we investigated the invasion of erythrocytes taking place during the asexual erythrocytic blood stage of the apicomplexan parasites Babesia bovis parasite. Host cell invasion by apicomplexan parasites is a complex process requiring multiple receptor-ligand interactions, involving

  16. The evolution of invasiveness in garden ants

    DEFF Research Database (Denmark)

    Cremer, Sylvia; Ugelvig, Line Vej; Drijfhout, Falko P

    2008-01-01

    It is unclear why some species become successful invaders whilst others fail, and whether invasive success depends on pre-adaptations already present in the native range or on characters evolving de-novo after introduction. Ants are among the worst invasive pests, with Lasius neglectus and its ra...

  17. Impact of the invasive parasitic copepod

    NARCIS (Netherlands)

    Goedknegt, M.A.; Bedolfe; Drent, J.; van der Meer, J.; Thieltges, D.W.

    2018-01-01

    Invasive species can indirectly affect native species by modifying parasite–host dynamics and disease occurrence. This scenario applies to European coastal waters where the invasive Pacific oyster (Magallana gigas) co-introduced the parasitic copepod Mytilicola orientalis that spills

  18. Alien invasive species and international trade

    Science.gov (United States)

    Emergency control measures for invasive species often rely on use of pesticides and other destructive practices. Public concern about pesticide contamination of the ground water and the environment has lead to increased restrictions on the use of pesticides for control of many destructive invasive ...

  19. Economic Analysis of Biological Invasions in Forests

    Science.gov (United States)

    Tomas P. Holmes; Julian Aukema; Jeffrey Englin; Robert G. Haight; Kent Kovacs; Brian Leung

    2014-01-01

    Biological invasions of native forests by nonnative pests result from complex stochastic processes that are difficult to predict. Although economic optimization models describe efficient controls across the stages of an invasion, the ability to calibrate such models is constrained by lack of information on pest population dynamics and consequent economic damages. Here...

  20. Book review: Encyclopedia of biological invasions

    Science.gov (United States)

    Qinfeng Guo

    2011-01-01

    Species introductions and consequent biotic invasions and homogenization are major components of global change that are drawing increasing concern and various levels of actions and reactions around the world. Invasion ecology has advanced rapidly during the last few decades, and the discipline is now increasingly integrated with the social and economic sciences. A...

  1. Allelopathic effects of invasive Eucalyptus camaldulensis on ...

    African Journals Online (AJOL)

    Eucalyptus camaldulensis Dehnh. (red river gum; Myrtaceae) is an invasive tree in riparian habitats of the Western Cape, South Africa, where it replaces indigenous vegetation and affects ecosystem functioning. These invasions lead to changes in river geomorphology and reduction in stream flow. The mechanisms that ...

  2. The Invasive Plant Species Education Guide

    Science.gov (United States)

    Mason, Kevin; James, Krista; Carlson, Kitrina; D'Angelo, Jean

    2010-01-01

    To help high school students gain a solid understanding of invasive plant species, university faculty and students from the University of Wisconsin-Stout (UW-Stout) and a local high school teacher worked together to develop the Invasive Plant Species (IPS) Education Guide. The IPS Education Guide includes nine lessons that give students an…

  3. Mapping invasive weeds using airborne hyperspectral imagery

    Science.gov (United States)

    Invasive plant species present a serious problem to the natural environment and have adverse ecological and economic impacts on both terrestrial and aquatic ecosystems they invade. This article provides a brief overview on the use of remote sensing for mapping invasive plant species in both terrestr...

  4. 76 FR 30955 - Invasive Species Advisory Committee

    Science.gov (United States)

    2011-05-27

    ... Commerce. The duty of the Council is to provide national leadership regarding invasive species issues... broad array of issues related to preventing the introduction of invasive species and providing for their... with Western-based scientists and practitioners on problems and potential solutions, as well as...

  5. Liver injury in invasive aspergillus. Echographic findings

    International Nuclear Information System (INIS)

    Otero Fernandez, R.; Garcia Revillo, J.; Paez Moreno, J.; Zurera Tendero, L.J.

    1994-01-01

    Aspergillus is the second most common mycoses in immuno compromised patients. The invasive form is associated with a mortality of approximately 100%. We present a case of invasive aspergillus in a heart transplant recipient in whom ultrasound disclosed the presence of liver injury which was later confirmed by necropsy. We review the available literature. (Author) 15 refs

  6. Domestic exotics and the perception of invasibility

    Science.gov (United States)

    Qinfeng Guo; Robert Ricklefs

    2010-01-01

    Susceptibility of an area to invasion by exotic species is often judged by the fraction of introduced species in the local biota. However, the degree of invasion, particularly in mainland areas, has often been underestimated because of the exclusion of ‘domestic exotics’ (those introduced to internal units from within the national border) in calculations. Because all...

  7. Invasive aspergillosis in paediatric oncology patients.

    Science.gov (United States)

    Muda, Z; Ibrahim, H; Abdulrahman, E J; Menon, B S; Zahari, Z; Zaleha, A M; Talib, A

    2008-12-01

    Invasive aspergillosis predominantly occurs in immunocompromised patients and is often resistant to different therapeutically strategies. However, mortality significantly increases if the central nervous system is affected. In this report we describe two cases of invasive aspergilosis, one with kidney involvement with a successful treatment while the other with pulmonary and cerebral involvement with a grave outcome.

  8. Principles for ecologically based invasive plant management

    Science.gov (United States)

    Jeremy J. James; Brenda S. Smith; Edward A. Vasquez; Roger L. Sheley

    2010-01-01

    Land managers have long identified a critical need for a practical and effective framework for designing restoration strategies, especially where invasive plants dominate. A holistic, ecologically based, invasive plant management (EBIPM) framework that integrates ecosystem health assessment, knowledge of ecological processes, and adaptive management into a successional...

  9. A proposed unified framework for biological invasions

    Czech Academy of Sciences Publication Activity Database

    Blackburn, T. M.; Pyšek, Petr; Bacher, S.; Carlton, J. T.; Duncan, R. P.; Jarošík, Vojtěch; Wilson, J. R. U.; Richardson, D. M.

    2011-01-01

    Roč. 26, č. 7 (2011), s. 333-339 ISSN 0169-5347 R&D Projects: GA ČR GA206/09/0563; GA MŠk LC06073 Institutional research plan: CEZ:AV0Z60050516 Keywords : biological invasions * invasion process * general framework Subject RIV: EF - Botanics Impact factor: 15.748, year: 2011

  10. Major element compositions of fluid inclusions from hydrothermal vein-type deposits record eroded sedimentary units in the Schwarzwald district, SW Germany

    Science.gov (United States)

    Walter, Benjamin F.; Burisch, Mathias; Marks, Michael A. W.; Markl, Gregor

    2017-12-01

    Mixing of sedimentary formation fluids with basement-derived brines is an important mechanism for the formation of hydrothermal veins. We focus on the sources of the sediment-derived fluid component in ore-forming processes and present a comprehensive fluid inclusion study on 84 Jurassic hydrothermal veins from the Schwarzwald mining district (SW Germany). Our data derive from about 2300 fluid inclusions and reveal differences in the average fluid composition between the northern, central, and southern Schwarzwald. Fluids from the northern and southern Schwarzwald are characterised by high salinities (18-26 wt% NaCl+CaCl2), low Ca/(Ca+Na) mole ratios (0.1-0.4), and variable Cl/Br mass ratios (30-1140). In contrast, fluids from the central Schwarzwald show even higher salinities (23-27 wt% NaCl+CaCl2), higher Ca/(Ca+Na) mole ratios (0.2-0.9), and less variable Cl/Br mass ratios (40-130). These fluid compositions correlate with the nature and thickness of the now eroded sedimentary cover rocks. Compared to the northern and the southern Schwarzwald, where halite precipitation occurred during the Middle Triassic, the sedimentary basin in the central Schwarzwald was relatively shallow at this time and no halite was precipitated. Accordingly, Cl/Br ratios of fluids from the central Schwarzwald provide no evidence for the reaction of a sedimentary brine with halite, whereas those from the northern and southern Schwarzwald do. Instead, elevated Ca/(Ca+Na), high SO4 contents, and relatively low Cl/Br imply the presence of a gypsum dissolution brine during vein formation in the central Schwarzwald which agrees with the reconstructed regional Triassic geology. Hence, the information archived in fluid inclusions from hydrothermal veins in the crystalline basement has the potential for reconstructing sedimentary rocks in the former overburden.

  11. New views on "old" carbon in the Amazon River: Insight from the source of organic carbon eroded from the Peruvian Andes

    Science.gov (United States)

    Clark, K. E.; Hilton, R. G.; West, A. J.; Malhi, Y.; Gröcke, D. R.; Bryant, C. L.; Ascough, P. L.; Robles Caceres, A.; New, M.

    2013-05-01

    rivers play a key role in the delivery of particulate organic carbon (POC) to large river systems and the ocean. Due to the extent of its drainage area and runoff, the Amazon River is one of Earth's most important biogeochemical systems. However, the source of POC eroded from the humid region of the Eastern Andes and the input of fossil POC from sedimentary rocks (POCfossil) remains poorly constrained. Here we collected suspended sediments from the Kosñipata River during flood events to better characterize Andean POC, measuring the nitrogen to organic carbon ratio (N/C), stable carbon isotopes (δ13Corg) and radiocarbon (Δ14Corg). Δ14Corg values ranged from -711‰ to -15‰, and significant linear trends between Δ14Corg, N/C and δ13Corg suggested that this reflects the mixing of POCfossil with very young organic matter (Δ14Corg 50‰) from the terrestrial biosphere (POCnon-fossil). Using N/C and Δ14Corg in an end-member mixing analysis, we quantify the fraction of POCfossil (to within 0.1) and find that it contributes a constant proportion of the suspended sediment mass (0.37 ± 0.03%) and up to 80% of total POC. In contrast, the relative contribution of POCnon-fossil was variable, being most important during the rising limb and peak discharges of flood events. The new data shed light on published measurements of "old" POC (low Δ14Corg) in Andean-fed tributaries of the Amazon River, with their Δ14Corg and δ13Corg values consistent with variable addition of POCfossil. The findings suggest a greater persistence of Andean POC in the lowland Amazon than previously recognized.

  12. Soil erodibility mapping using the RUSLE model to prioritize erosion control in the Wadi Sahouat basin, North-West of Algeria.

    Science.gov (United States)

    Toubal, Abderrezak Kamel; Achite, Mohammed; Ouillon, Sylvain; Dehni, Abdelatif

    2018-03-12

    Soil losses must be quantified over watersheds in order to set up protection measures against erosion. The main objective of this paper is to quantify and to map soil losses in the Wadi Sahouat basin (2140 km 2 ) in the north-west of Algeria, using the Revised Universal Soil Loss Equation (RUSLE) model assisted by a Geographic Information System (GIS) and remote sensing. The Model Builder of the GIS allowed the automation of the different operations for establishing thematic layers of the model parameters: the erosivity factor (R), the erodibility factor (K), the topographic factor (LS), the crop management factor (C), and the conservation support practice factor (P). The average annual soil loss rate in the Wadi Sahouat basin ranges from 0 to 255 t ha -1  year -1 , maximum values being observed over steep slopes of more than 25% and between 600 and 1000 m elevations. 3.4% of the basin is classified as highly susceptible to erosion, 4.9% with a medium risk, and 91.6% at a low risk. Google Earth reveals a clear conformity with the degree of zones to erosion sensitivity. Based on the soil loss map, 32 sub-basins were classified into three categories by priority of intervention: high, moderate, and low. This priority is available to sustain a management plan against sediment filling of the Ouizert dam at the basin outlet. The method enhancing the RUSLE model and confrontation with Google Earth can be easily adapted to other watersheds.

  13. Predator control promotes invasive dominated ecological states.

    Science.gov (United States)

    Wallach, Arian D; Johnson, Christopher N; Ritchie, Euan G; O'Neill, Adam J

    2010-08-01

    Invasive species are regarded as one of the top five drivers of the global extinction crisis. In response, extreme measures have been applied in an attempt to control or eradicate invasives, with little success overall. We tested the idea that state shifts to invasive dominance are symptomatic of losses in ecosystem resilience, due to the suppression of apex predators. This concept was investigated in Australia where the high rate of mammalian extinctions is largely attributed to the destructive influence of invasive species. Intensive pest control is widely applied across the continent, simultaneously eliminating Australia's apex predator, the dingo (Canis lupus dingo). We show that predator management accounts for shifts between two main ecosystem states. Lethal control fractures dingo social structure and leads to bottom-up driven increases in invasive mesopredators and herbivores. Where control is relaxed, dingoes re-establish top-down regulation of ecosystems, allowing for the recovery of biodiversity and productivity.

  14. Erodabilidad de suelos del sur de la Región Semiárida argentina Erodibility of soils in the south of the semiarid region of Argentina

    Directory of Open Access Journals (Sweden)

    Nora E Echeverría

    2006-07-01

    Full Text Available La erodabilidad de los suelos se puede medir a campo mediante simuladores de lluvia o predecir mediante modelos matemáticos como USLE y WEPP. El objetivo del trabajo fue medir la erodabilidad de tres suelos representativos del Sur de la Región semiárida argentina y compararla con la estimada por los modelos WEPP y USLE. En los suelos Bahía Blanca (SBB y Cabildo (SC -Paleustoles Petrocálcicos- y Villarino (SV -Calciustol Petrocálcicose aplicaron, mediante un simulador portátil, dos lluvias consecutivas de 32 mm en 30 minutos. Las pérdidas de suelo debido a la 1° y 2° lluvia indicaron: SV 3,26 y 5,86 Mg ha-1 h-1; SC 2,04 y 5,53 Mg ha-1 h-1; SBB 0,75 y 2,66 Mg ha-1 h-1, respectivamente. La resistencia del suelo a la erosión correlacionó con la relación limo: arcilla (r:0,60, CO (r:0,55 y estabilidad estructural (r:0,56.Las tasas de escurrimiento y sedimentación promedio fueron para SV: 12,4 10-6 m s-1 y 15,6 10-5 kg s-1 m-2; para SC: 9,9 10-6 m s-1 y 13,5 10-5 kg s-1 m-2 y para SBB: 9,6 10-6 m s-1 y 6,1 10-5 kg s-1 m-2, respectivamente. El comportamiento de SV se debió al rápido sellado del horizonte superficial, mientras que el de SBB y el SC se relacionó con la estabilidad estructural. En el modelo WEPP, la erodabilidad medida entre surcos (Ki fue, para SV: 2,5; SC: 1,89 y SBB: 1,39 (10(6 kg s m-4; mientras que la estimada (Kib fue significativamente más alta, SV: 6,26; SC: 10,2 y SBB: 10,2 (10(6 kg s m-4. Los índices de erosión (IE fueron, SV: 0,30; SC: 0,21 y SBB: 0,10 Mg MJ-1 y discreparon significativamente de los valores K estimados a partir del nomograma, confirmando que las predicciones del mismo resultan poco confiables en suelos con el 65% o más de arenas.Water erodibility of soils can be measured in the field using rainfall simulators or be predicted with mathematical models as USLE and WEPP. The objective of our research was to determine water erodibility of three representative soils in the southern semiarid

  15. [Soil anti-erodibility of abandoned lands during different succession stages of plant community in hilly-gullied region of the Loess Plateau: Take Fangta small watershed as an example].

    Science.gov (United States)

    Yan, Fang-chen; Jiao, Ju-ying; Cao, Bin-ting; Yu, Wei-jie; Wei, Yan-hong; Kou, Meng; Hu, Shu

    2016-01-01

    Field survey and laboratory experiment were conducted to study the soil anti-erodibility of abandoned croplands during different vegetation succession stages in hilly-gullied region of the Loess Plateau, based on the analysis of soil particle composition, size distribution and group characteristics, soil aggregate fractal dimensions and stability. The results showed that in the earlier stages of succession from annual to perennial herbs in abandoned croplands, soil size distribution changed a little bit, the fractal dimension of soil particle increased, soil structure improved, fractal dimension and damage percent of soil aggregate structure decreased, soil stability increased, thus soil anti-erodibility increased. Therefore, natural restoration of vegetation is of great significance to improve the soil structure, increase soil erosion resistance, reduce soil erosion and promote sustainable development of regional ecological environment.

  16. A human breast cell model of pre-invasive to invasive transition

    Energy Technology Data Exchange (ETDEWEB)

    Bissell, Mina J; Rizki, Aylin; Weaver, Valerie M.; Lee, Sun-Young; Rozenberg, Gabriela I.; Chin, Koei; Myers, Connie A.; Bascom, Jamie L.; Mott, Joni D.; Semeiks, Jeremy R.; Grate, Leslie R.; Mian, I. Saira; Borowsky, Alexander D.; Jensen, Roy A.; Idowu, Michael O.; Chen, Fanqing; Chen, David J.; Petersen, Ole W.; Gray, Joe W.; Bissell, Mina J.

    2008-03-10

    A crucial step in human breast cancer progression is the acquisition of invasiveness. There is a distinct lack of human cell culture models to study the transition from pre-invasive to invasive phenotype as it may occur 'spontaneously' in vivo. To delineate molecular alterations important for this transition, we isolated human breast epithelial cell lines that showed partial loss of tissue polarity in three-dimensional reconstituted-basement membrane cultures. These cells remained non-invasive; however, unlike their non-malignant counterparts, they exhibited a high propensity to acquire invasiveness through basement membrane in culture. The genomic aberrations and gene expression profiles of the cells in this model showed a high degree of similarity to primary breast tumor profiles. The xenograft tumors formed by the cell lines in three different microenvironments in nude mice displayed metaplastic phenotypes, including squamous and basal characteristics, with invasive cells exhibiting features of higher grade tumors. To find functionally significant changes in transition from pre-invasive to invasive phenotype, we performed attribute profile clustering analysis on the list of genes differentially expressed between pre-invasive and invasive cells. We found integral membrane proteins, transcription factors, kinases, transport molecules, and chemokines to be highly represented. In addition, expression of matrix metalloproteinases MMP-9,-13,-15,-17 was up regulated in the invasive cells. Using siRNA based approaches, we found these MMPs to be required for the invasive phenotype. This model provides a new tool for dissection of mechanisms by which pre-invasive breast cells could acquire invasiveness in a metaplastic context.

  17. Invasive cancer cells and metastasis

    Science.gov (United States)

    Mierke, Claudia Tanja

    2013-12-01

    The physics of cancer is a relatively new emerging field of cancer research. In the last decade it has become a focus of biophysical research as well as becoming a novel focus for classical cancer research. This special section of Physical Biology focusing on invasive cancer cells and metastasis (physical oncology) will give greater insight into the different subfields where physical approaches are being applied to cancer research. This focus on the physical aspects of cancer is necessary because novel approaches in the field of genomics and proteomics have not altered the field of cancer research dramatically, due to the fact that few breakthroughs have been made. It is still not understood why some primary tumors metastasize and thus have a worse outcome compared to others that do not metastasize. As biophysicists, we and others suggest that the mechanical properties of the cancer cells, which possess the ability to transmigrate, are quite different compared to non-metastatic and non-invasive cancer cells. Furthermore, we hypothesize that these cancer cells undergo a selection process within the primary tumor that enables them to weaken their cell-cell adhesions and to alter their cell-matrix adhesions in order to be able to cross the outermost boundary of the primary tumor, as well as the surrounding basement membrane, and to invade the connective tissue. This prerequisite may also help the cancer cells to enter blood or lymph vessels, get transported with the vessel flow and form secondary tumors either within the vessel, directly on the endothelium, or in a different organ after crossing the endothelial lining a second time. This special section begins with a paper by Mark F Coughlin and Jeffrey J Fredberg on the changes in cytoskeletal dynamics and nonlinear rheology due to the metastatic capability of cancer cells from different cancer tissue types such as skin, bladder, prostate and kidney [1]. The hypothesis was that the metastatic outcome is impacted by

  18. Invasive Candidiasis: An Overview from Taiwan

    Directory of Open Access Journals (Sweden)

    Sheng-Yuan Ruan

    2009-06-01

    Full Text Available Invasive candidiasis has emerged as an important nosocomial infection, especially in critically ill patients. We review the epidemiology of invasive candidiasis with an emphasis on data from Taiwan. An increasing incidence of candidemia became apparent from 1980 to the end of the 1990s, followed by relative stability. Crude mortality rates of patients with candidemia were in the range of 35% to 60%. Candida albicans remains the predominant cause of invasive candidiasis in Taiwan and accounts for more than 50% of all cases. Candida tropicalis, Candida glabrata and Candida parapsilosis are the three most common nonalbicansCandida species that cause invasive candidiasis. The above four Candida species account for more than 90% of invasive candidiasis in Taiwan. Overall, invasive Candida isolates have remained highly susceptible to fluconazole (> 90% susceptibility over the past two decades. However, periodic surveillance is needed to monitor antifungal resistance because reduced fluconazole susceptibility in non-albicans Candida is not an uncommon trend. Voriconazole and echinocandins continue to exhibit excellent in vitro activity against invasive Candida isolates.

  19. Invasive Aspergillosis in Hematological Patients.

    Science.gov (United States)

    Kimura, Shun-Ichi

    2016-01-01

    Invasive aspergillosis (IA) is still one of the leading causes of morbidity and mortality in hematological patients, although its outcome has been improving. Prolonged and profound neutropenia in patients receiving intensive chemotherapy for acute leukemia and stem cell transplantation is a major risk factor for IA. Allogeneic stem cell transplant recipients with graft-versus-host disease and corticosteroid use are also at high risk. Management in a protective environment with high efficiency particular air (HEPA) filter is generally recommended to prevent aspergillosis in patients with prolonged and profound neutropenia. Antifungal prophylaxis against Aspergillus species should be considered in patients with past history of aspergillosis or colonization of Aspergillus species, at facilities with high incidence of IA and those without a protective environment. Early diagnosis and prompt antifungal treatment is important to improve outcome. Imaging studies such as computed tomography and biomarkers such as galactomannan antigen and β-D-glucan are useful for early diagnosis. Empirical antifungal treatment based on persistent or recurrent fever during neutropenia despite broad-spectrum antibiotic therapy is generally recommended in high-risk patients. Alternatively, a preemptive treatment strategy has recently been proposed in the context of progress in the early diagnosis of IA based on the results of imaging studies and biomarkers. Voriconazole is recommended for initial therapy for IA. Liposomal amphotericin B is considered as alternative initial therapy. Combination antifungal therapy of echinocandin with voriconazole or liposomal amphotericin B could be a choice for refractory cases.

  20. Robotic assisted minimally invasive surgery

    Directory of Open Access Journals (Sweden)

    Palep Jaydeep

    2009-01-01

    Full Text Available The term "robot" was coined by the Czech playright Karel Capek in 1921 in his play Rossom′s Universal Robots. The word "robot" is from the check word robota which means forced labor.The era of robots in surgery commenced in 1994 when the first AESOP (voice controlled camera holder prototype robot was used clinically in 1993 and then marketed as the first surgical robot ever in 1994 by the US FDA. Since then many robot prototypes like the Endoassist (Armstrong Healthcare Ltd., High Wycombe, Buck, UK, FIPS endoarm (Karlsruhe Research Center, Karlsruhe, Germany have been developed to add to the functions of the robot and try and increase its utility. Integrated Surgical Systems (now Intuitive Surgery, Inc. redesigned the SRI Green Telepresence Surgery system and created the daVinci Surgical System ® classified as a master-slave surgical system. It uses true 3-D visualization and EndoWrist ® . It was approved by FDA in July 2000 for general laparoscopic surgery, in November 2002 for mitral valve repair surgery. The da Vinci robot is currently being used in various fields such as urology, general surgery, gynecology, cardio-thoracic, pediatric and ENT surgery. It provides several advantages to conventional laparoscopy such as 3D vision, motion scaling, intuitive movements, visual immersion and tremor filtration. The advent of robotics has increased the use of minimally invasive surgery among laparoscopically naοve surgeons and expanded the repertoire of experienced surgeons to include more advanced and complex reconstructions.

  1. Invasive pathogen threatens bird-pine mutualism: implications for sustaining a high-elevation ecosystem.

    Science.gov (United States)

    McKinney, Shawn T; Fiedler, Carl E; Tomback, Diana F

    2009-04-01

    Human-caused disruptions to seed-dispersal mutualisms increase the extinction risk for both plant and animal species. Large-seeded plants can be particularly vulnerable due to highly specialized dispersal systems and no compensatory regeneration mechanisms. Whitebark pine (Pinus albicaulis), a keystone subalpine species, obligately depends upon the Clark's Nutcracker (Nucifraga columbiana) for dispersal of its large, wingless seeds. Clark's Nutcracker, a facultative mutualist with whitebark pine, is sensitive to rates of energy gain, and emigrates from subalpine forests during periods of cone shortages. The invasive fungal pathogen Cronartium ribicola, which causes white pine blister rust, reduces whitebark pine cone production by killing cone-bearing branches and trees. Mortality from blister rust reaches 90% or higher in some whitebark pine forests in the Northern Rocky Mountains, USA, and the rust now occurs nearly rangewide in whitebark pine. Our objectives were to identify the minimum level of cone production necessary to elicit seed dispersal by nutcrackers and to determine how cone production is influenced by forest structure and health. We quantified forest conditions and ecological interactions between nutcrackers and whitebark pine in three Rocky Mountain ecosystems that differ in levels of rust infection and mortality. Both the frequency of nutcracker occurrence and probability of seed dispersal were strongly related to annual whitebark pine cone production, which had a positive linear association with live whitebark pine basal area, and negative linear association with whitebark pine tree mortality and rust infection. From our data, we estimated that a threshold level of approximately 1000 cones/ha is needed for a high likelihood of seed dispersal by nutcrackers (probability > or = 0.7), and that this level of cone production can be met by forests with live whitebark pine basal area > 5.0 m2/ha. The risk of mutualism disruption is greatest in northern

  2. Study of melanoma invasion by FTIR spectroscopy

    Science.gov (United States)

    Yang, Y.; Sulé-Suso, J.; Sockalingum, G. D.

    2008-02-01

    Compared to other forms of skin cancer, a malignant melanoma has a high risk of spreading to other parts of the body. Melanoma invasion is a complex process involving changes in cell-extracellular matrix (ECM) interaction and cell-cell interactions. To fully understand the factors which control the invasion process, a human skin model system was reconstructed. HBL (a commercially available cell line) melanoma cells were seeded on a skin model with and without the presence of keratinocytes and/or fibroblasts. After 14 days culture, the skin specimens were fixed, parafin embedded and cut into 7 µm sections. The de-parafinised sections were investigated by synchrotron Fourier transformed infrared (FTIR) microspectroscopy to study skin cell invasion behaviour. The advantage of using FTIR is its ability to obtain the fingerprint information of the invading cells in terms of protein secondary structure in comparison to non-invading cells and the concentration of the enzyme (matrix-metalloproteinase) which digests protein matrix, near the invading cells. With aid of the spectral mapping images, it is possible to pinpoint the cells in non-invasion and invasion area and analyse the respective spectra. It has been observed that the protein bands in cells and matrix shifted between non-invasive and invasive cells in the reconstructed skin model. We hypothesise that by careful analysis of the FTIR data and validation by other models, FTIR studies can reveal information on which type of cells and proteins are involved in melanoma invasion. Thus, it is possible to trace the cell invasion path by mapping the spectra along the interface of cell layer and matrix body by FTIR spectroscopy.

  3. Invasive clonal plant species have a greater root-foraging plasticity than non-invasive ones.

    Science.gov (United States)

    Keser, Lidewij H; Dawson, Wayne; Song, Yao-Bin; Yu, Fei-Hai; Fischer, Markus; Dong, Ming; van Kleunen, Mark

    2014-03-01

    Clonality is frequently positively correlated with plant invasiveness, but which aspects of clonality make some clonal species more invasive than others is not known. Due to their spreading growth form, clonal plants are likely to experience spatial heterogeneity in nutrient availability. Plasticity in allocation of biomass to clonal growth organs and roots may allow these plants to forage for high-nutrient patches. We investigated whether this foraging response is stronger in species that have become invasive than in species that have not. We used six confamilial pairs of native European clonal plant species differing in invasion success in the USA. We grew all species in large pots under homogeneous or heterogeneous nutrient conditions in a greenhouse, and compared their nutrient-foraging response and performance. Neither invasive nor non-invasive species showed significant foraging responses to heterogeneity in clonal growth organ biomass or in aboveground biomass of clonal offspring. Invasive species had, however, a greater positive foraging response in terms of root and belowground biomass than non-invasive species. Invasive species also produced more total biomass. Our results suggest that the ability for strong root foraging is among the characteristics promoting invasiveness in clonal plants.

  4. Fort Collins Science Center: Invasive Species Science

    Science.gov (United States)

    Stohlgren, Tom

    2004-01-01

    Invasive, non-native species of plants, animals, and disease organisms adversely affect the ecosystems they enter. Like "biological wildfires," they can quickly spread, and they affect nearly all terrestrial and aquatic ecosystems. Invasive species have become the greatest environmental challenge of the 21st century in terms of economic, environmental, and human health costs, with an estimated impact in the U.S. of over $138 billion per year. Managers of Department of the Interior and other public and private lands and waters rank invasive species as their top resource management problem.

  5. Extracellular Molecules Involved in Cancer Cell Invasion

    International Nuclear Information System (INIS)

    Stivarou, Theodora; Patsavoudi, Evangelia

    2015-01-01

    Nowadays it is perfectly clear that understanding and eradicating cancer cell invasion and metastasis represent the crucial, definitive points in cancer therapeutics. During the last two decades there has been a great interest in the understanding of the extracellular molecular mechanisms involved in cancer cell invasion. In this review, we highlight the findings concerning these processes, focusing in particular on extracellular molecules, including extracellular matrix proteins and their receptors, growth factors and their receptors, matrix metalloproteinases and extracellular chaperones. We report the molecular mechanisms underlying the important contribution of this pool of molecules to the complex, multi-step phenomenon of cancer cell invasion

  6. Extracellular Molecules Involved in Cancer Cell Invasion

    Directory of Open Access Journals (Sweden)

    Theodora Stivarou

    2015-01-01

    Full Text Available Nowadays it is perfectly clear that understanding and eradicating cancer cell invasion and metastasis represent the crucial, definitive points in cancer therapeutics. During the last two decades there has been a great interest in the understanding of the extracellular molecular mechanisms involved in cancer cell invasion. In this review, we highlight the findings concerning these processes, focusing in particular on extracellular molecules, including extracellular matrix proteins and their receptors, growth factors and their receptors, matrix metalloproteinases and extracellular chaperones. We report the molecular mechanisms underlying the important contribution of this pool of molecules to the complex, multi-step phenomenon of cancer cell invasion.

  7. Beautiful, but also potentially invasive

    Directory of Open Access Journals (Sweden)

    Lipták Boris

    2015-03-01

    Full Text Available Introduction of non-indigenous exotic species to new areas, where they may establish viable populations and become invasive, is a considerable problem in the protection of nature worldwide, as these species may alter the indigenous species population structure and potentially even decrease the biodiversity. The European fauna underwent through major negative changes on the continent and nowadays, it experiences another new treat, represented by the expanding aquarium pet trade, and with it, associated species (and disease introductions. Exotic freshwater crustaceans are one of the taxa widely incorporated in the business, counting a remarkable number of species. Recent records of the exotic marbled crayfish or Marmorkrebs (Procambarus fallax f. virginalis in German in open ecosystems in Slovakia pointed to human-mediated introductions associated with aquarium pet trade in the country. In this regard, a study of the aquarium pet trade both in expositions and shops and online was assessed. Several crustacean taxa are available both in pet trade exhibitions and online through the Internet. Altogether 26 different species were identified in the aquarium trade in Slovakia. These are Procambarus fallax f. virginalis, P. clarkii, P. alleni, Cherax quadricarinatus, C. destructor, C. holthuisi, C. peknyi, Cambarellus patzcuarensis and C. diminutus occurring in the aquarium pet trade in Slovakia (n = 9. Procambarus fallax f. virginalis, P. clarkii and C. patzuarensis are the most common in this regard. There is also a quantity of other related taxa in the aquarium pet trade in Slovakia, mainly Caridina spp. (n = 5, Neocaridina spp. (n = 4, Atyopsis moluccensis, Atya gabonensis, Arachnochium kulsiense and several taxa of exotic crabs (n = 5 belonging to three different genera (Cardiosoma, Geosesarma and Gecarinus present. Neocaridina davidi is identified as the most frequent in this regard. As some of the species can become established and form viable

  8. Radio frequency energy for non-invasive and minimally invasive skin tightening.

    Science.gov (United States)

    Mulholland, R Stephen

    2011-07-01

    This article reviews the non-invasive and minimally invasive options for skin tightening, focusing on peer-reviewed articles and presentations and those technologies with the most proven or promising RF non-excisional skin-tightening results for excisional surgeons. RF has been the mainstay of non-invasive skin tightening and has emerged as the "cutting edge" technology in the minimally invasive skin-tightening field. Because these RF skin-tightening technologies are capital equipment purchases with a significant cost associated, this article also discusses some business issues and models that have proven to work in the plastic surgeon's office for non-invasive and minimally invasive skin-tightening technologies. Copyright © 2011 Elsevier Inc. All rights reserved.

  9. Heart bypass surgery - minimally invasive - discharge

    Science.gov (United States)

    ... invasive direct coronary artery bypass - discharge; MIDCAB - discharge; Robot assisted coronary artery bypass - discharge; RACAB - discharge; Keyhole ... M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health ...

  10. Invasive aspergillosis in near drowning nonneutropenic patient.

    Science.gov (United States)

    Munta, Kartik; Gopal, Palepu B N; Vigg, Ajit

    2015-12-01

    Invasive aspergillosis in immunosuppressed people has been well documented, but to diagnose and treat in an immunocompetent individual after near drowning, it requires early suspicion and proper empirical treatment. We report a case diagnosed to have invasive aspergillosis with systemic dissemination of the infection to the brain, gluteal muscles, and kidneys after a fall in a chemical tank of a paper manufacturing company. He was ventilated for acute respiratory distress syndrome and managed with antibiotics and vasopressors. Due to nonresolving pneumonia and positive serum galactomannan, trans-tracheal biopsy was performed which confirmed invasive aspergillosis and was treated with antifungals. With the availability of galactomannan assay and better radiological investigative modalities, occurrence of such invasive fungal infections in cases of drowning patients should be considered early in such patients and treated with appropriate antifungals.

  11. [Invasive yeast infections in neutropenic patients].

    Science.gov (United States)

    Ruiz Camps, Isabel; Jarque, Isidro

    2016-01-01

    Invasive fungal diseases caused by yeasts still play an important role in the morbidity and mortality in neutropenic patients with haematological malignancies. Although the overall incidence of invasive candidiasis has decreased due to widespread use of antifungal prophylaxis, the incidence of non-Candida albicans Candida species is increasing compared with that of C.albicans, and mortality of invasive candidiasis continues to be high. In addition, there has been an increase in invasive infections caused by an array of uncommon yeasts, including species of the genus Malassezia, Rhodotorula, Trichosporon and Saprochaete, characterised by their resistance to echinocandins and poor prognosis. Copyright © 2016 Asociación Española de Micología. Publicado por Elsevier España, S.L.U. All rights reserved.

  12. NNDSS - Table II. Invasive Pneumococcal to Legionellosis

    Data.gov (United States)

    U.S. Department of Health & Human Services — NNDSS - Table II. Invasive Pneumococcal to Legionellosis - 2014.In this Table, all conditions with a 5-year average annual national total of more than or equals...

  13. Providing intraosseous anesthesia with minimal invasion.

    Science.gov (United States)

    Giffin, K M

    1994-08-01

    A new variation of intraosseous anesthesia--crestal anesthesia--that is rapid, site-specific and minimally invasive is presented. The technique uses alveolar crest nutrient canals for anesthetic delivery without penetrating either bone or periodontal ligament.

  14. NNDSS - Table II. Invasive Pneumococcal to Legionellosis

    Data.gov (United States)

    U.S. Department of Health & Human Services — NNDSS - Table II. Invasive Pneumococcal to Legionellosis - 2015.In this Table, provisional cases of selected notifiable diseases (≥1,000 cases reported during the...

  15. NNDSS - Table II. Invasive Pneumococcal to Legionellosis

    Data.gov (United States)

    U.S. Department of Health & Human Services — NNDSS - Table II. Invasive Pneumococcal to Legionellosis - 2016. In this Table, provisional* cases of selected† notifiable diseases (≥1,000 cases reported during the...

  16. The evolution of invasiveness in garden ants.

    Directory of Open Access Journals (Sweden)

    Sylvia Cremer

    Full Text Available It is unclear why some species become successful invaders whilst others fail, and whether invasive success depends on pre-adaptations already present in the native range or on characters evolving de-novo after introduction. Ants are among the worst invasive pests, with Lasius neglectus and its rapid spread through Europe and Asia as the most recent example of a pest ant that may become a global problem. Here, we present the first integrated study on behavior, morphology, population genetics, chemical recognition and parasite load of L. neglectus and its non-invasive sister species L. turcicus. We find that L. neglectus expresses the same supercolonial syndrome as other invasive ants, a social system that is characterized by mating without dispersal and large networks of cooperating nests rather than smaller mutually hostile colonies. We conclude that the invasive success of L. neglectus relies on a combination of parasite-release following introduction and pre-adaptations in mating system, body-size, queen number and recognition efficiency that evolved long before introduction. Our results challenge the notion that supercolonial organization is an inevitable consequence of low genetic variation for chemical recognition cues in small invasive founder populations. We infer that low variation and limited volatility in cuticular hydrocarbon profiles already existed in the native range in combination with low dispersal and a highly viscous population structure. Human transport to relatively disturbed urban areas thus became the decisive factor to induce parasite release, a well established general promoter of invasiveness in non-social animals and plants, but understudied in invasive social insects.

  17. The Evolution of Invasiveness in Garden Ants

    Science.gov (United States)

    Cremer, Sylvia; Ugelvig, Line V.; Drijfhout, Falko P.; Schlick-Steiner, Birgit C.; Steiner, Florian M.; Seifert, Bernhard; Hughes, David P.; Schulz, Andreas; Petersen, Klaus S.; Konrad, Heino; Stauffer, Christian; Kiran, Kadri; Espadaler, Xavier; d'Ettorre, Patrizia; Aktaç, Nihat; Eilenberg, Jørgen; Jones, Graeme R.; Nash, David R.; Pedersen, Jes S.; Boomsma, Jacobus J.

    2008-01-01

    It is unclear why some species become successful invaders whilst others fail, and whether invasive success depends on pre-adaptations already present in the native range or on characters evolving de-novo after introduction. Ants are among the worst invasive pests, with Lasius neglectus and its rapid spread through Europe and Asia as the most recent example of a pest ant that may become a global problem. Here, we present the first integrated study on behavior, morphology, population genetics, chemical recognition and parasite load of L. neglectus and its non-invasive sister species L. turcicus. We find that L. neglectus expresses the same supercolonial syndrome as other invasive ants, a social system that is characterized by mating without dispersal and large networks of cooperating nests rather than smaller mutually hostile colonies. We conclude that the invasive success of L. neglectus relies on a combination of parasite-release following introduction and pre-adaptations in mating system, body-size, queen number and recognition efficiency that evolved long before introduction. Our results challenge the notion that supercolonial organization is an inevitable consequence of low genetic variation for chemical recognition cues in small invasive founder populations. We infer that low variation and limited volatility in cuticular hydrocarbon profiles already existed in the native range in combination with low dispersal and a highly viscous population structure. Human transport to relatively disturbed urban areas thus became the decisive factor to induce parasite release, a well established general promoter of invasiveness in non-social animals and plants, but understudied in invasive social insects. PMID:19050762

  18. Invasive crayfish in the Pacific Northwest

    Science.gov (United States)

    Pearl, Christopher A.; McCreary, Brome; Adams, Michael

    2011-01-01

    Invasive species directly threaten freshwater biodiversity, particularly in regions of high aquatic richness like the Pacific Northwest (PNW). Crayfish are among the most impactful of aquatic invasive species. Invasive crayfish are considered ecosystem engineers due to their ability to alter basic wetland properties, such as reducing vegetation and bank integrity and increasing turbidity. In areas where invasion is advanced, crayfish pose major economic and ecological problems. Crayfish have been widely introduced for aquaculture and can become established in a wide range of habitat conditions. They also may be spread by anglers who use them as bait. Several non-native crayfish are established in the PNW, but the extent of their invasion is not well known. At least two groups are known from scattered sites in the PNW, and both have proven problematic for native species in other parts of the world: Red swamp crayfish (Procambarus clarkii) and several members of the genus Orconectes. Both groups are native to areas of the eastern United States. Both are identified globally as invasives of high concern and appear on the Oregon Department of Fish and Wildlife's "10 Most Unwanted" and the U.S. Forest Service's "Primary Species of Concern" lists for stream systems in the PNW. Despite the presence of introduced crayfish in the PNW and their high potential for negative effects, the scope of their invasion and effects on aquatic systems are not well known. The U.S. Geological Survey (USGS), along with local groups and state agencies, is working to clarify crayfish distribution and to outline which basins may not yet be invaded. Other goals are to improve understanding of habitat associations of invasive crayfish and their potential effects on native crayfish.

  19. Effects of invasive plants on arthropods.

    Science.gov (United States)

    Litt, Andrea R; Cord, Erin E; Fulbright, Timothy E; Schuster, Greta L

    2014-12-01

    Non-native plants have invaded nearly all ecosystems and represent a major component of global ecological change. Plant invasions frequently change the composition and structure of vegetation communities, which can alter animal communities and ecosystem processes. We reviewed 87 articles published in the peer-reviewed literature to evaluate responses of arthropod communities and functional groups to non-native invasive plants. Total abundance of arthropods decreased in 62% of studies and increased in 15%. Taxonomic richness decreased in 48% of studies and increased in 13%. Herbivorous arthropods decreased in response to plant invasions in 48% of studies and increased in 17%, likely due to direct effects of decreased plant diversity. Predaceous arthropods decreased in response to invasive plants in 44% of studies, which may reflect indirect effects due to reductions in prey. Twenty-two percent of studies documented increases in predators, which may reflect changes in vegetation structure that improved mobility, survival, or web-building for these species. Detritivores increased in 67% of studies, likely in response to increased litter and decaying vegetation; no studies documented decreased abundance in this functional group. Although many researchers have examined effects of plant invasions on arthropods, sizeable information gaps remain, specifically regarding how invasive plants influence habitat and dietary requirements. Beyond this, the ability to predict changes in arthropod populations and communities associated with plant invasions could be improved by adopting a more functional and mechanistic approach. Understanding responses of arthropods to invasive plants will critically inform conservation of virtually all biodiversity and ecological processes because so many organisms depend on arthropods as prey or for their functional roles, including pollination, seed dispersal, and decomposition. Given their short generation times and ability to respond rapidly to

  20. Soil modification by invasive plants: Effects on native and invasive species of mixed-grass prairies

    Science.gov (United States)

    Jordan, N.R.; Larson, D.L.; Huerd, S.C.

    2008-01-01

    Invasive plants are capable of modifying attributes of soil to facilitate further invasion by conspecifics and other invasive species. We assessed this capability in three important plant invaders of grasslands in the Great Plains region of North America: leafy spurge (Euphorbia esula), smooth brome (Bromus inermis) and crested wheatgrass (Agropyron cristatum). In a glasshouse, these three invasives or a group of native species were grown separately through three cycles of growth and soil conditioning in both steam-pasteurized and non-pasteurized soils, after which we assessed seedling growth in these soils. Two of the three invasive species, Bromus and Agropyron, exhibited significant self-facilitation via soil modification. Bromus and Agropyron also had significant facilitative effects on other invasives via soil modification, while Euphorbia had significant antagonistic effects on the other invasives. Both Agropyron and Euphorbia consistently suppressed growth of two of three native forbs, while three native grasses were generally less affected. Almost all intra- and interspecific effects of invasive soil conditioning were dependent upon presence of soil biota from field sites where these species were successful invaders. Overall, these results suggest that that invasive modification of soil microbiota can facilitate plant invasion directly or via 'cross-facilitation' of other invasive species, and moreover has potential to impede restoration of native communities after removal of an invasive species. However, certain native species that are relatively insensitive to altered soil biota (as we observed in the case of the forb Linum lewisii and the native grasses), may be valuable as 'nurse'species in restoration efforts. ?? 2007 Springer Science+Business Media B.V.

  1. Coupling legacy geomorphic surface facies to riparian vegetation: Assessing red cedar invasion along the Missouri River downstream of Gavins Point dam, South Dakota

    Science.gov (United States)

    Greene, Samantha L.; Knox, James C.

    2014-01-01

    Floods increase fluvial complexity by eroding established surfaces and creating new alluvial surfaces. As dams regulate channel flow, fluvial complexity often decreases and the hydro-eco-geomorphology of the riparian habitat changes. Along the Missouri River, flow regulation resulted in channel incision of 1-3 m within the study area and disconnected the pre-dam floodplain from the channel. Evidence of fluvial complexity along the pre-dam Missouri River floodplain can be observed through the diverse depositional environments represented by areas of varying soil texture. This study evaluates the role of flow regulation and depositional environment along the Missouri River in the riparian invasion of red cedar downstream of Gavins Point dam, the final dam on the Missouri River. We determine whether invasion began before or after flow regulation, determine patterns of invasion using Bayesian t-tests, and construct a Bayesian multivariate linear model of invaded surfaces. We surveyed 59 plots from 14 riparian cottonwood stands for tree age, plot composition, plot stem density, and soil texture. Red cedars existed along the floodplain prior to regulation, but at a much lower density than today. We found 2 out of 565 red cedars established prior to regulation. Our interpretation of depositional environments shows that the coarser, sandy soils reflect higher energy depositional pre-dam surfaces that were geomorphically active islands and point bars prior to flow regulation and channel incision. The finer, clayey soils represent lower energy depositional pre-dam surfaces, such as swales or oxbow depressions. When determining patterns of invasion for use in a predictive statistical model, we found that red cedar primarily establishes on the higher energy depositional pre-dam surfaces. In addition, as cottonwood age and density decrease, red cedar density tends to increase. Our findings indicate that flow regulation caused hydrogeomorphic changes within the study area that

  2. Invasion and predation in aquatic ecosystems

    Directory of Open Access Journals (Sweden)

    Judith S. WEIS

    2011-10-01

    Full Text Available This article reviews biological invasions in which predation (or its absence plays a major role in the success of the invader. Examples are described in which the invader out-competes native species for the same food, and cases in which the invader consumes valued native species. In many instances, better predator avoidance by the invasive species or the absence of predators in the new habitat contributes to the success of the invaders; in other cases native or introduced predators appear to be able to keep the invasive species in check. A relatively new management approach in the US is the idea of adding another trophic level – to have humans act as the predators and consume the invasive species. This approach is being utilized in Florida and throughout the Caribbean against the lionfish, but could be extended to other fishes, as well as to various invasive crustaceans and mollusks. This idea is controversial, and current regulations prohibiting the possession of individuals of the invasive species (e.g., mitten crabs or snakefish would preclude the development of a fishery for them [Current Zoology 57 (5: 613–624, 2011].

  3. Invasive Species Science Branch: research and management tools for controlling invasive species

    Science.gov (United States)

    Reed, Robert N.; Walters, Katie D.

    2015-01-01

    Invasive, nonnative species of plants, animals, and disease organisms adversely affect the ecosystems they enter. Like “biological wildfires,” they can quickly spread and affect nearly all terrestrial and aquatic ecosystems. Invasive species have become one of the greatest environmental challenges of the 21st century in economic, environmental, and human health costs, with an estimated effect in the United States of more than $120 billion per year. Managers of the Department of the Interior and other public and private lands often rank invasive species as their top resource management problem. The Invasive Species Science Branch of the Fort Collins Science Center provides research and technical assistance relating to management concerns for invasive species, including understanding how these species are introduced, identifying areas vulnerable to invasion, forecasting invasions, and developing control methods. To disseminate this information, branch scientists are developing platforms to share invasive species information with DOI cooperators, other agency partners, and the public. From these and other data, branch scientists are constructing models to understand and predict invasive species distributions for more effective management. The branch also has extensive herpetological and population biology expertise that is applied to harmful reptile invaders such as the Brown Treesnake on Guam and Burmese Python in Florida.

  4. Worldwide Alien Invasion: A Methodological Approach to Forecast the Potential Spread of a Highly Invasive Pollinator.

    Directory of Open Access Journals (Sweden)

    André L Acosta

    Full Text Available The ecological impacts of alien species invasion are a major threat to global biodiversity. The increasing number of invasion events by alien species and the high cost and difficulty of eradicating invasive species once established require the development of new methods and tools for predicting the most susceptible areas to invasion. Invasive pollinators pose serious threats to biodiversity and human activity due to their close relationship with many plants (including crop species and high potential competitiveness for resources with native pollinators. Although at an early stage of expansion, the bumblebee species Bombus terrestris is becoming a representative case of pollinator invasion at a global scale, particularly given its high velocity of invasive spread and the increasing number of reports of its impacts on native bees and crops in many countries. We present here a methodological framework of habitat suitability modeling that integrates new approaches for detecting habitats that are susceptible to Bombus terrestris invasion at a global scale. Our approach did not include reported invaded locations in the modeling procedure; instead, those locations were used exclusively to evaluate the accuracy of the models in predicting suitability over regions already invaded. Moreover, a new and more intuitive approach was developed to select the models and evaluate different algorithms based on their performance and predictive convergence. Finally, we present a comprehensive global map of susceptibility to Bombus terrestris invasion that highlights priority areas for monitoring.

  5. Fluid challenge: tracking changes in cardiac output with blood pressure monitoring (invasive or non-invasive).

    Science.gov (United States)

    Lakhal, Karim; Ehrmann, Stephan; Perrotin, Dominique; Wolff, Michel; Boulain, Thierry

    2013-11-01

    To assess whether invasive and non-invasive blood pressure (BP) monitoring allows the identification of patients who have responded to a fluid challenge, i.e., who have increased their cardiac output (CO). Patients with signs of circulatory failure were prospectively included. Before and after a fluid challenge, CO and the mean of four intra-arterial and oscillometric brachial cuff BP measurements were collected. Fluid responsiveness was defined by an increase in CO ≥10 or ≥15% in case of regular rhythm or arrhythmia, respectively. In 130 patients, the correlation between a fluid-induced increase in pulse pressure (Δ500mlPP) and fluid-induced increase in CO was weak and was similar for invasive and non-invasive measurements of BP: r² = 0.31 and r² = 0.29, respectively (both p area under the receiver-operating curve (AUC) of 0.82 (0.74-0.88), similar (p = 0.80) to that of non-invasive Δ500mlPP [AUC of 0.81 (0.73-0.87)]. Outside large gray zones of inconclusive values (5-23% for invasive Δ500mlPP and 4-35% for non-invasive Δ500mlPP, involving 35 and 48% of patients, respectively), the detection of responsiveness or unresponsiveness to fluid was reliable. Cardiac arrhythmia did not impair the performance of invasive or non-invasive Δ500mlPP. Other BP-derived indices did not outperform Δ500mlPP. As evidenced by large gray zones, BP-derived indices poorly reflected fluid responsiveness. However, in our deeply sedated population, a high increase in invasive pulse pressure (>23%) or even in non-invasive pulse pressure (>35%) reliably detected a response to fluid. In the absence of a marked increase in pulse pressure (<4-5%), a response to fluid was unlikely.

  6. Minimal Invasive Urologic Surgery and Postoperative Ileus

    Directory of Open Access Journals (Sweden)

    Fouad Aoun

    2015-07-01

    Full Text Available Postoperative ileus (POI is the most common cause of prolonged length of hospital stays (LOS and associated healthcare costs. The advent of minimal invasive technique was a major breakthrough in the urologic landscape with great potential to progress in the future. In the field of gastrointestinal surgery, several studies had reported lower incidence rates for POI following minimal invasive surgery compared to conventional open procedures. In contrast, little is known about the effect of minimal invasive approach on the recovery of bowel motility after urologic surgery. We performed an overview of the potential benefit of minimal invasive approach on POI for urologic procedures. The mechanisms and risk factors responsible for the onset of POI are discussed with emphasis on the advantages of minimal invasive approach. In the urologic field, POI is the main complication following radical cystectomy but it is rarely of clinical significance for other minimal invasive interventions. Laparoscopy or robotic assisted laparoscopic techniques when studied individually may reduce to their own the duration and prevent the onset of POI in a subset of procedures. The potential influence of age and urinary diversion type on postoperative ileus is contradictory in the literature. There is some evidence suggesting that BMI, blood loss, urinary extravasation, existence of a major complication, bowel resection, operative time and transperitoneal approach are independent risk factors for POI. Treatment of POI remains elusive. One of the most important and effective management strategies for patients undergoing radical cystectomy has been the development and use of enhanced recovery programs. An optimal rational strategy to shorten the duration of POI should incorporate minimal invasive approach when appropriate into multimodal fast track programs designed to reduce POI and shorten LOS.

  7. Plant invasions in China: an emerging hot topic in invasion science

    Directory of Open Access Journals (Sweden)

    Jian Liu

    2012-12-01

    Full Text Available China has shown a rapid economic development in recent decades, and several drivers of this change are known to enhance biological invasions, a major cause of biodiversity loss. Here we review the current state of research on plant invasions in China by analyzing papers referenced in the ISI Web of Knowledge. Since 2001, the number of papers has increased exponentially, indicating that plant invasions in China are an emerging hot topic in invasion science. The analyzed papers cover a broad range of methodological approaches and research topics. While more that 250 invasive plant species with negative impacts have been reported from China, only a few species have been considered in more than a handful of papers (in order of decreasing number of references: Spartina alterniflora, Ageratina adenophora, Mikania micrantha, Alternanthera philoxeroides, Solidago canadensis, Eichhornia crassipes. Yet this selection might rather reflect the location of research teams than the most invasive plant species in China. Considering the previous achievements in China found in our analysis research in plant invasions could be expanded by (1 compiling comprehensive lists of non-native plant species at the provincial and national scales and to include species that are native to one part of China but non-native to others in these lists; (2 strengthening pathways studies (primary introduction to the country, secondary releases within the country to enhance prevention and management; and (3 assessing impacts of invasive species at different spatial scales (habitats, regions and in relation to conservation resources.

  8. Updated Scar Management Practical Guidelines: Non-invasive and invasive measures

    NARCIS (Netherlands)

    Monstrey, S.; Middelkoop, E.; Vranckx, J.J.; Bassetto, F.; Ziegler, U.E.; Meaume, S.; Teot, L.

    2014-01-01

    Hypertrophic scars and keloids can be aesthetically displeasing and lead to severe psychosocial impairment. Many invasive and non-invasive options are available for the plastic (and any other) surgeon both to prevent and to treat abnormal scar formation. Recently, an updated set of practical

  9. Spillover but no spillback of two invasive parasitic copepods from invasive Pacific oysters (

    NARCIS (Netherlands)

    Goedknegt, M.A.; Schuster, A.-K.; Buschbaum, C.; Gergs, R.; Jung, A.; Luttikhuizen, P.C.; Van der Meer, J.; Troost, K.; Wegner, K.M.; Thieltges, D.W.

    2017-01-01

    Invasive species can cause indirect effects on native biota by modifying parasite-host interactions and disease occurrence in native species. This study investigated the role of the invasive Pacific oyster (Crassostrea gigas) in potential spillover (co-introduced parasites infect native hosts) and

  10. Integrating invasive species policies across ornamental horticulture supply chains to prevent plant invasions

    NARCIS (Netherlands)

    Hulme, Philip E.; Brundu, Giuseppe; Carboni, Marta; Dehnen-schmutz, Katharina; Dullinger, Stefan; Early, Regan; Essl, Franz; González-moreno, Pablo; Groom, Quentin J.; Kueffer, Christoph; Kühn, Ingolf; Maurel, Noëlie; Novoa, Ana; Pergl, Jan; Pyšek, Petr; Seebens, Hanno; Tanner, Rob; Touza, Julia M.; Van Kleunen, Mark; Verbrugge, Laura Nicoline Halley

    2017-01-01

    1.Ornamental horticulture is the primary pathway for invasive alien plant introductions. We critically appraise published evidence on the effectiveness of four policy instruments that tackle invasions along the horticulture supply chain: pre-border import restrictions, post-border bans, industry

  11. Efficient distinction of invasive aquatic plant species from non-invasive related species using DNA barcoding

    NARCIS (Netherlands)

    Ghahramanzadeh, R.; Esselink, G.; Kodde, L.P.; Duistermaat, H.; Valkenburg, van J.L.C.H.; Marashi, S.H.; Smulders, M.J.M.; Wiel, van de C.C.M.

    2013-01-01

    Biological invasions are regarded as threats to global biodiversity. Among invasive aliens, a number of plant species belonging to the genera Myriophyllum, Ludwigia and Cabomba, and to the Hydrocharitaceae family pose a particular ecological threat to water bodies. Therefore, one would try to

  12. The relation between invasive and non-invasive tear break-up time ...

    African Journals Online (AJOL)

    Tear stability normal to Nigerians with consideration of gender and age has not been reported. Tear stability in young adults was measured using invasive and non-invasive tear break-up time (TBUT and NIBUT). Forty –five subjects aged 20 to 30 years were selected from among the students of University of. Benin, Edo ...

  13. Earthworm invasion in North America: Food resource competition affects native millipede survival and invasive earthworm reproduction

    Science.gov (United States)

    Bruce Snyder; Mac Callaham; Christopher Lowe; Paul Hendrix

    2013-01-01

    The invasive non-native earthworm Amynthas agrestis (Goto and Hatai, 1899) has recently been documented invading forests of the Appalachian Mountains in the southeastern United States. This epigeic earthworm decreases the depth of organic soil horizons, and this may play a role in the decrease of millipede richness and abundance associated with A. agrestis invasion. To...

  14. Invasive cervical carcinoma (Stages IB-IIB)

    International Nuclear Information System (INIS)

    Sironi, S.; Zanello, A.; Rodighiero, M.G.; Vanzulli, A.; Del Maschio, A.; Taccagni, G.L.; Belloni, C.

    1991-01-01

    In the patients with invasive cervical carcinoma, the accurate assessment of parametrial invasion greatly affects the therapeutic choice between surgery and radiation therapy. As a matter of fact, surgery is usually performed only in the patients with carcinoma confined to the cervix, whereas those with parametrial involvement, or more advanced stages, are treated with radiation therapy. This prospective study was aimed at investigating the comparative adequecy of CT and MR imaging in assessing parametrial status in the patients with invasive cervical cancer. Twenty-one consecutive patients, with histologic diagnosis of cervical carcinoma, were investigated. All of them were clinically considered as having invasive cervical cancer (FIGO stage IB-IIB) and subsequently underwent surgery. In all cases, detailed histology of the parametrium was obtained. Pathological data were compared with CT and MR findings in all cases. As for assessing parametrial involvement by cancer, CT had 62% accuracy, 63% sensitivity, and 60% specificity, versus MR imaging 81% accuracy, 69% sensitivity, and 80% specificify. Therefore, MR imaging appears to be superior to CT in assessing the parametrial status of patients with invasive cervical carcinoma; the method yields valuable information for treatment planning

  15. Cell signaling during Trypanosoma cruzi invasion

    Directory of Open Access Journals (Sweden)

    Fernando Yukio Maeda

    2012-11-01

    Full Text Available Cell signaling is an essential requirement for mammalian cell invasion by Trypanosoma cruzi. Depending on the parasite strain and the parasite developmental form, distinct signaling pathways may be induced. In this short review, we focus on the data coming from studies with metacyclic trypomastigotes (MT generated in vitro and tissue culture-derived trypomastigotes (TCT, used as counterparts of insect-borne and bloodstream parasites respectively. During invasion of host cells by MT or TCT, intracellular Ca2+ mobilization and host cell lysosomal exocytosis are triggered. Invasion mediated by MT surface molecule gp82 requires the activation of mammalian target of rapamycin (mTOR, phosphatidylinositol 3-kinase (PI3K and protein kinase C (PKC in the host cell, associated with Ca2+-dependent disruption of the actin cytoskeleton. In MT, protein tyrosine kinase (PTK, PI3K, phospholipase C (PLC and PKC appear to be activated. TCT invasion, on the other hand, does not rely on mTOR activation, rather on target cell PI3K, and may involve the host cell autophagy for parasite internalization. Enzymes, such oligopeptidase B and the major T. cruzi cysteine proteinase cruzipain, have been shown to generate molecules that induce target cell Ca2+ signal. In addition, TCT may trigger host cell responses mediated by TGF-β receptor or integrin family member. Further investigations are needed for a more complete and detailed picture of T. cruzi invasion.

  16. Current research in perineural invasion of cholangiocarcinoma

    Directory of Open Access Journals (Sweden)

    Deng Xi-Yun

    2010-03-01

    Full Text Available Abstract Background Perineural invasion is a common path for cholangiocarcinoma (CCA metastasis, and it is highly correlated with postoperative recurrence and poor prognosis. It is often an early event in a disease that is commonly diagnosed in advanced stages, and thus it could offer a timely therapeutic and diagnostic target if better understood. This article systematically reviews the progress of CCA neural invasion-related molecules. Methods Studies were identified by searching MEDLINE and PubMed databases for articles from January 1990 to December 2009, using the keywords "cholangiocarcinoma," "perineural invasion," "nerve growth factor"(NGF, "neural cell adhesion molecule" (NCAM, "matrix metalloproteinase"(MMP, "neurotransmitter," "acetylcholine" (Ach, and "transforming growth factor" (TGF." Additional papers and book chapters were identified by a manual search of references from the key articles. Results From above we found that the molecules NGF, NCAM, MMP, Ach and TGF may have prognostic significance in, and offer clues to the mechanism of CCA neural invasion. Conclusions Cholangiocarcinoma's increasing worldwide incidence is especially poignant in view of both the lacking effective therapies, and the fact that it is commonly diagnosed in advanced stages. As CCA neural invasion often appears early, more complete characterization of its molecular pathology could lead to the identification of targets for the diagnosis and therapy of this devastating malignancy.

  17. Synchronous lobular carcinoma in situ and invasive lobular cancer: marker or precursor for invasive lobular carcinoma.

    Science.gov (United States)

    Wallace, A S; Xiang, D; Hockman, L; Arya, M; Jeffress, J; Wang, Z; Dale, P S

    2014-10-01

    Lobular carcinoma in situ (LCIS) is a known risk factor for invasive breast carcinoma, but there is increasing data indicating a possible precursor relationship. This study investigates the incidence of lobular carcinoma in situ that occurs with invasive lobular carcinoma (ILC). Women diagnosed with ILC or LCIS from 2000 to 2010 were retrospectively identified and reviewed after institutional review board approval. This group was divided into two cohorts: ILC alone, and LCIS and ILC (ILC/LCIS). Patient demographics, disease characteristics, and treatment modalities were captured. p invasive ductal carcinoma at ∼40%. The association of pre-invasive and invasive lobular lesions should be further studied in a large scale prospective study to assess for a precursor relationship. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Erodibilidade e tensão crítica de cisalhamento em solos de estradas não pavimentadas Erodibility and critical shear stress on unpaved road soils

    Directory of Open Access Journals (Sweden)

    João F. de Oliveira

    2009-12-01

    Full Text Available A falta de um sistema adequado para drenagem de águas pluviais em estradas não pavimentadas é um dos principais fatores que causam a sua degradação e, para que referidos sistemas possam ser adequadamente planejados e dimensionados é necessário o conhecimento de parâmetros de resistência dos solos. Com este trabalho se teve, por objetivo, determinar a erodibilidade e a tensão crítica de cisalhamento para diferentes solos de estradas não pavimentadas. Utilizou-se um simulador de escoamento superficial instalado diretamente nos canais das estradas, sob condição natural e se determinou a perda de solo para diferentes lâminas de escoamento. A erodibilidade e a tensão crítica de cisalhamento foram determinadas por meio do ajuste de curvas relacionando-se a perda de solo em função da tensão cisalhante provocada pelo escoamento. Os resultados alcançados mostraram variações nos valores de erodibilidade e de tensão crítica de cisalhamento das estradas avaliadas. Os valores de erodibilidade encontrados mostraram, quando comparados com valores observados na literatura, elevada suscetibilidade à erosão para as condições de estradas, sendo mais elevados nos solos de textura mais arenosa e siltosa. Os valores de tensão crítica se mostraram bastante próximos aos observados em outros trabalhos.The absence of an adequate drainage system in unpaved roads is one of the main factors for their degradation. For adequate planning knowledge of the resistance parameters of soil is necessary. This study had as its objective the determinatiom of the erodibility and critical shear stress of unpaved road soils. For this work, a runoff simulator was directly installed on road channels, under natural conditions. Different flow depths were applied and the soil loss was measured for each depth. The erodibility and the critical shear stress were determined through adjusted curves relating soil disaggregation and flow shear stress. The results

  19. Genomic comparison of invasive and rare non-invasive strains reveals Porphyromonas gingivalis genetic polymorphisms

    Directory of Open Access Journals (Sweden)

    Svetlana Dolgilevich

    2011-03-01

    Full Text Available Porphyromonas gingivalis strains are shown to invade human cells in vitro with different invasion efficiencies, varying by up to three orders of magnitude.We tested the hypothesis that invasion-associated interstrain genomic polymorphisms are present in P. gingivalis and that putative invasion-associated genes can contribute to P. gingivalis invasion.Using an invasive (W83 and the only available non-invasive P. gingivalis strain (AJW4 and whole genome microarrays followed by two separate software tools, we carried out comparative genomic hybridization (CGH analysis.We identified 68 annotated and 51 hypothetical open reading frames (ORFs that are polymorphic between these strains. Among these are surface proteins, lipoproteins, capsular polysaccharide biosynthesis enzymes, regulatory and immunoreactive proteins, integrases, and transposases often with abnormal GC content and clustered on the chromosome. Amplification of selected ORFs was used to validate the approach and the selection. Eleven clinical strains were investigated for the presence of selected ORFs. The putative invasion-associated ORFs were present in 10 of the isolates. The invasion ability of three isogenic mutants, carrying deletions in PG0185, PG0186, and PG0982 was tested. The PG0185 (ragA and PG0186 (ragB mutants had 5.1×103-fold and 3.6×103-fold decreased in vitro invasion ability, respectively.The annotation of divergent ORFs suggests deficiency in multiple genes as a basis for P. gingivalis non-invasive phenotype. Access the supplementary material to this article: Supplement, table (see Supplementary files under Reading Tools online.

  20. The concentrations of heavy metals and the incidence of micronucleated erythrocytes and liver EROD activity in two edible-fish from the Paraíba do Sul river basin in Brazil | Concentração de metais pesados e incidência de eritrócitos micronucleados e atividade de EROD hepática em duas espécies de peixes comestíveis na bacia do Rio Paraíba do Sul, Brasil

    Directory of Open Access Journals (Sweden)

    Thiago Estevam Martins Parente

    2015-02-01

    Full Text Available The Paraíba do Sul river (PSR basin crosses one of the most populated and industrialized regions of Brazil and receives effluent from the metallurgic, paper mill and agricultural industries. PSR water has multiple uses, including being a supply of potable water and riverine populations which consume some species of its fish. In the present study, we investigated the responses of two biomarkers of aquatic pollution, EROD activity in the liver and micronuclei frequency in peripheral blood, as well as the concentrations of seven heavy metals in the muscle tissue of two species of fish native to the PSR: Geophagus brasiliensis and Hypostomus sp. Sampling was performed in both the wet and dry seasons of 2003, with a total of 339 fish collected from 16 sites along the PSR basin. Fish collected at Levy Gasparian, Barra Mansa and Três Rios both had higher EROD activity and micronuclei frequency. The results also suggested a moderate induction of EROD activity in fish collected from S.L. Paraitinga and Sapucaia. Micronuclei frequency was elevated in fish from S.J. Campos, Além Paraíba, Campos and S.J. Barra. In all cases, heavy metal concentrations did not exceed the maximum considered safe for fish meat consumption. -------------------------------------------------------------------------------------------- A bacia do rio Paraíba do Sul (PSR atravessa uma das regiões mais povoadas e industrializadas do Brasil, recebendo efluentes de indústrias metalúrgicas, de papel e celulose e agrícolas. Os usos das águas do PSR são múltiplos, incluem o fornecimento de água potável, e as populações ribeirinhas consomem algumas de suas espécies de peixes. No presente trabalho foram investigadas as respostas de dois biomarcadores à poluição, a atividade hepática de EROD e a freqüência de micronúcleo em sangue periférico, e medidos os níveis de sete metais pesados no músculo de duas espécies de peixes nativas do PSR, Geophagus brasiliensis and

  1. [Lobular neoplasms and invasive lobular breast cancer].

    Science.gov (United States)

    Sinn, H-P; Helmchen, B; Heil, J; Aulmann, S

    2014-02-01

    The term lobular neoplasia (LN) comprises both atypical lobular hyperplasia (ALH), and lobular carcinoma in situ (LCIS) and thus a spectrum of morphologically heterogeneous but clinically and biologically related lesions. LN is regarded as a nonobligatory precursor lesion of invasive breast cancer and at the same time as an indicator lesion for ipsilateral and contralateral breast cancer risk of the patient. Rare pleomorphic or florid variants of LCIS must be differentiated from classical LCIS. The classical type of invasive lobular carcinoma (ILC) can be distinguished from the non-special type of invasive breast cancer (NST) by E-cadherin inactivation, loss of E-cadherin related cell adhesion and the subsequent discohesive growth pattern. Variant forms of ILC may show different molecular features, and solid and pleomorphic differentiation patterns in cases of high grade variants. Important parameters for the prognostic assessment of ILC are tumor grading and the recognition of morphological variants.

  2. Mechatronic Feasibility of Minimally Invasive, Atraumatic Cochleostomy

    Directory of Open Access Journals (Sweden)

    Tom Williamson

    2014-01-01

    Full Text Available Robotic assistance in the context of lateral skull base surgery, particularly during cochlear implantation procedures, has been the subject of considerable research over the last decade. The use of robotics during these procedures has the potential to provide significant benefits to the patient by reducing invasiveness when gaining access to the cochlea, as well as reducing intracochlear trauma when performing a cochleostomy. Presented herein is preliminary work on the combination of two robotic systems for reducing invasiveness and trauma in cochlear implantation procedures. A robotic system for minimally invasive inner ear access was combined with a smart drilling tool for robust and safe cochleostomy; evaluation was completed on a single human cadaver specimen. Access to the middle ear was successfully achieved through the facial recess without damage to surrounding anatomical structures; cochleostomy was completed at the planned position with the endosteum remaining intact after drilling as confirmed by microscope evaluation.

  3. Computed tomography versus invasive coronary angiography

    DEFF Research Database (Denmark)

    Napp, Adriane E.; Haase, Robert; Laule, Michael

    2017-01-01

    Objectives: More than 3.5 million invasive coronary angiographies (ICA) are performed in Europe annually. Approximately 2 million of these invasive procedures might be reduced by noninvasive tests because no coronary intervention is performed. Computed tomography (CT) is the most accurate...... angiography (ICA) is the reference standard for detection of CAD.• Noninvasive computed tomography angiography excludes CAD with high sensitivity.• CT may effectively reduce the approximately 2 million negative ICAs in Europe.• DISCHARGE addresses this hypothesis in patients with low-to-intermediate pretest...

  4. Biosensors and invasive monitoring in clinical applications

    CERN Document Server

    Córcoles, Emma P

    2013-01-01

    This volume examines the advances of invasive monitoring by means of biosensors and microdialysis. Physical and physiological parameters are commonly monitored in clinical settings using invasive techniques due to their positive outcome in patients’ diagnosis and treatment. Biochemical parameters, however, still rely on off-line measurements and require large pieces of equipment. Biosensing and sampling devices present excellent capabilities for their use in continuous monitoring of patients’ biochemical parameters. However, certain issues remain to be solved in order to ensure a more widespread use of these techniques in today’s medical practices.

  5. Pepducin Based Intervention of Breast Cancer Invasion

    Science.gov (United States)

    2006-08-01

    Metalloprotease-1 Receptor that Promotes Invasion and Tumorigenesis of Breast Cancer Cells. Cell 120, 303-313. (6) Arribas , J. (2005) Matrix Metalloproteases...promotes invasion and tumorigenesis of breast cancer cells. Cell 2005;120:303–13. 6. Arribas J. Matrix metalloproteases and tumor inva- sion. N Engl J Med...to ala - provide a model for more aggressive, tamoxifen-insen- nine. The F43A PAR1 mutant does not transduce a sig- sitive, breast cancers. MDA-MB-231

  6. Invasion rate and population characteristics of the invasive round goby Neogobius melanostomus: effects of density and invasion history

    DEFF Research Database (Denmark)

    Azour, Farivar; Deurs, Mikael van; Behrens, Jane

    2015-01-01

    Round goby Neogobius melanostomus is currently one of the most wide-ranging invasive fish species in Europe and North America. The present study demonstrates how the distribution of round goby has expanded from 2008 to 2013 at a rate of about 30 km yr−1 along the Danish coastline in the western B...

  7. The complexity underlying invasiveness precludes the identification of invasive traits: A comparative study of invasive and noninvasive heterocarpic Atriplex congeners

    Czech Academy of Sciences Publication Activity Database

    Doudová, J.; Douda, J.; Mandák, Bohumil

    2017-01-01

    Roč. 12, č. 4 (2017), s. 1-16, č. článku e017645. E-ISSN 1932-6203 Institutional support: RVO:67985939 Keywords : Atriplex * heterocarpy * invasiveness Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 2.806, year: 2016

  8. Differentiating invasive and pre-invasive lung cancer by quantitative analysis of histopathologic images

    Science.gov (United States)

    Zhou, Chuan; Sun, Hongliu; Chan, Heang-Ping; Chughtai, Aamer; Wei, Jun; Hadjiiski, Lubomir; Kazerooni, Ella

    2018-02-01

    We are developing automated radiopathomics method for diagnosis of lung nodule subtypes. In this study, we investigated the feasibility of using quantitative methods to analyze the tumor nuclei and cytoplasm in pathologic wholeslide images for the classification of pathologic subtypes of invasive nodules and pre-invasive nodules. We developed a multiscale blob detection method with watershed transform (MBD-WT) to segment the tumor cells. Pathomic features were extracted to characterize the size, morphology, sharpness, and gray level variation in each segmented nucleus and the heterogeneity patterns of tumor nuclei and cytoplasm. With permission of the National Lung Screening Trial (NLST) project, a data set containing 90 digital haematoxylin and eosin (HE) whole-slide images from 48 cases was used in this study. The 48 cases contain 77 regions of invasive subtypes and 43 regions of pre-invasive subtypes outlined by a pathologist on the HE images using the pathological tumor region description provided by NLST as reference. A logistic regression model (LRM) was built using leave-one-case-out resampling and receiver operating characteristic (ROC) analysis for classification of invasive and pre-invasive subtypes. With 11 selected features, the LRM achieved a test area under the ROC curve (AUC) value of 0.91+/-0.03. The results demonstrated that the pathologic invasiveness of lung adenocarcinomas could be categorized with high accuracy using pathomics analysis.

  9. Aplicación del bioensayo EROD-H4IIE para la determinación de dioxinas en carnes de pollos broiler: un estudio de equivalencia con la cromatografía de gases de alta resolución acoplada a espectrometría de masas de alta resolución Application of the EROD-H4IIE bioassay for the determination of dioxins in broiler chicken meat: an equivalence study with high resolution gas chromatography coupled to high resolution mass spectrometry

    OpenAIRE

    JT Schoffer; C Bustos-López; P Sotomayor; CA Mattar; A González; C Robles; F Samsing; O Acevedo; CE Valdovinos

    2011-01-01

    En el presente estudio se aplicó el bioensayo EROD con línea celular H4IIE para determinar la equivalencia de resultados para carnes de pollo, entre el bioensayo EROD-H4IIE en pg TCDD-EQ/g de tejido y los resultados de la cromatografía de gases de alta resolución acoplada a espectrometría de alta resolución (HRGC/HRMS) en pg WHO-TEQ/g de grasa. Para lo anterior se utilizaron 41 muestras compuestas de trutros de pollo. Éstas fueron obtenidas en la planta faenadora de 4 planteles diferentes de ...

  10. Erosividade da chuva e erodibilidade de Cambissolo e Latossolo na região de Lavras, sul de Minas Gerais Rainfall erosivity and erodibility of Cambisol (Inceptisol and Latosol (Oxisol in the region of Lavras, Southern Minas Gerais State, Brazil

    Directory of Open Access Journals (Sweden)

    Antonio Marcos da Silva

    2009-12-01

    Full Text Available No Brasil, ainda são relativamente poucos os estudos envolvendo erodibilidade do solo, principalmente Cambissolos, dada a morosidade na obtenção dos resultados de experimentos com chuva natural. O conhecimento dos índices de erosividade e de erodibilidade é importante para o planejamento conservacionista, contribuindo para a sustentabilidade dos solos. Este estudo teve como objetivos determinar a erosividade da chuva e a erodibilidade de Cambissolo Háplico Tb distrófico típico e Latossolo Vermelho distroférrico típico, sob chuva natural, em Lavras (MG, no período de 1998 a 2002. Os dados de precipitação pluviométrica foram obtidos na Estação Climatológica Principal de Lavras, localizada no campus da Universidade Federal de Lavras, próxima das unidades experimentais de perdas de solo. A erosividade (EI30 foi determinada a partir do produto da energia cinética da chuva pela sua intensidade máxima em 30 min. Estes dados, correlacionados com as perdas de solo, permitiram obter o índice de erodibilidade dos solos. A precipitação total média anual foi 1.287 mm e a erosividade média foi de 4.865 MJ mm ha-1 h-1 ano-1. A erodibilidade foi 0,0355 Mg h MJ-1 mm-1 para o Cambissolo e 0,0032 Mg h MJ-1 mm-1 para o Latossolo, em consonância com seus atributos mineralógicos, químicos, físicos e morfológicos diferenciais.Relatively few studies in Brazil have investigated soil erodibility, mainly for Cambisols (Inceptisols, due to the tediousness of data collection in natural rainfall experiments. Knowledge about erodibility and erosivity is important for conservation planning, which contributes to soil sustainability. This study aimed at evaluating the rainfall erosivity and erodibility of a typic dystrophic Tb Haplic Cambisol (Inceptisol and a typic dystroferric Red Latosol (Oxisol under natural rainfall, in Lavras, state of Minas Gerais, Brazil, between 1998 and 2002. Pluvial precipitation data were obtained from the main weather

  11. Biological invasions, ecological resilience and adaptive governance

    Science.gov (United States)

    In a world of increasing interconnections in global trade as well as rapid change in climate and land cover, the accelerating introduction and spread of invasive species is a critical concern due to associated negative social and ecological impacts, both real and perceived. Much...

  12. Invasive plants affect prairie soil biology

    Science.gov (United States)

    Non-native or exotic plants often cause ecological and environmental damage in ecosystems where they invade and become established. These invasive plants may be the most serious threat to plant diversity in prairies, especially those in scattered remnants, which may be particularly vulnerable to rap...

  13. The October 2011 Kenyan invasion of Somalia

    DEFF Research Database (Denmark)

    Olsen, Gorm Rye

    2018-01-01

    -Kenyan origin who pursued their own interests. Security and economic concerns did play a role, while the paper dismisses that the invasion can be understood as a consequence of the Kenyan government pursuing an ‘international image management strategy’. Theoretically, the paper concludes that ‘Western’ theories...

  14. Benefit from the minimally invasive sinus technique.

    Science.gov (United States)

    Salama, N; Oakley, R J; Skilbeck, C J; Choudhury, N; Jacob, A

    2009-02-01

    Sinus drainage is impeded by the transition spaces that the anterior paranasal sinuses drain into, not the ostia themselves. Addressing the transition spaces and leaving the ostia intact, using the minimally invasive sinus technique, should reverse chronic rhinosinusitis. To assess patient benefit following use of the minimally invasive sinus technique for chronic rhinosinusitis. One hundred and forty-three consecutive patients underwent the minimally invasive sinus technique for chronic rhinosinusitis. Symptoms (i.e. blocked nose, poor sense of smell, rhinorrhoea, post-nasal drip, facial pain and sneezing) were recorded using a visual analogue scale, pre-operatively and at six and 12 weeks post-operatively. Patients were also surveyed using the Glasgow benefit inventory, one and three years post-operatively. We found a significant reduction in all nasal symptom scores at six and 12 weeks post-operatively, and increased total quality of life scores at one and three years post-operatively (25.2 and 14.8, respectively). The patient benefits of treatment with the minimally invasive sinus technique compare with the published patient benefits for functional endoscopic sinus surgery.

  15. Invasive species in southern Nevada [Chapter 4

    Science.gov (United States)

    Mathew L. Brooks; Steven M. Ostoja; Jeanne C. Chambers

    2013-01-01

    Southern Nevada contains a wide range of topographies, elevations, and climatic zones emblematic of its position at the ecotone between the Mojave Desert, Great Basin, and Colorado Plateau ecoregions. These varied environmental conditions support a high degree of biological diversity (Chapter 1), but they also provide opportunities for a wide range of invasive species...

  16. Invasive plants often emanate from southern gardens

    Science.gov (United States)

    J.H. Miller; A. Miller

    2009-01-01

    Did you know that heavenly bamboo, thorny olive, English ivy, Boston fern, privets and many garden favorites are invading forests to their and thus our detriment? Garden clubs should band together to protect our natural vegetation against invasive plants that take over the habitat of the native flora. Often called non-native, exotic, or noxious weeds, they...

  17. Invasive thymoma; Radiologic evaluation by computed tomography

    International Nuclear Information System (INIS)

    Yoon, Choon Sik; Choe, Kyu Ok

    1985-01-01

    In 6 cases of invasive thymoma proved histologically from 1981 to 1984 in Yonsei University Medical Center, the CT findings and pattern were analysed. The results were as follows; 1. Of 6 cases, 4 were males and 2 were females. All cases were between 40-64 years and the average was 51 year old. 2. Of 6 cases, 2 female patients were associated with myasthenia gravis. 3. By the histological examination, 2 were confirmed as mixed cell type, 2 spindle cell type, 1 lymphocytic type and 1 epithelial cell type. 4. CT findings of invasive thymoma were 1) A discrete but lobulated and irregular marginated soft tissue mass in the superoanterior mediastinum replacing the normal mediastinal fat tissue. 2) Usually irregular low density areas within the mass suggesting central necrosis or calcification in 1 of 6 cases was noted. 3) Local invasiveness of the mass shown as obliteration of the normal fat plans surrounding great vessels, irregular thickening or nodular shadows of the pleura, diagphragm and pericardium and irregular and ragged tumor-lung interfaces if the tumor invade to the structures. 4) Frequent extension of tumor to middle and post. mediastinum along pericardium or mediastinal pleura with resultant extrinsic indentation and/or invasion of the hilar region. 5). Extensive tumor infiltration to middle and post. mediastinum in 1 case, indistinguishable from lymphoma. 6) Low attenuation numbered area of brain in another 1 case, but not confirmed histologically

  18. Invasive pests—insects and diseases

    Science.gov (United States)

    Donald A. Duerr; Paul A. Mistretta

    2013-01-01

    Key FindingsNonnative pest species have increasing impacts in the South regardless of climate change, patterns of land ownership, or changes in the composition of vegetation.“New” nonnative invasive insects and diseases will have serious impacts on southern forests over the next 50 years. Some species such as emerald ash borer...

  19. Elephant invasion and escalated depletion of environmental ...

    African Journals Online (AJOL)

    For decades, elephants' invasion is known to be associated with severe environmental consequences leading to escalated depletion o environmental resources (plants, water, wildlife and soil). This paper examined the effects of elephants' activity on the environmental resources inHong and Gombi Local Government areas ...

  20. Socioeconomic legacy yields an invasion debt

    Czech Academy of Sciences Publication Activity Database

    Essl, F.; Dullinger, S.; Rabitsch, W.; Hulme, P. E.; Hülber, K.; Jarošík, Vojtěch; Kleinbauer, I.; Krausmann, F.; Kuhn, H.; Nentwig, W.; Vila, M.; Genovesi, P.; Gherardi, F.; Desprez-Loustau, M.-L.; Roques, A.; Pyšek, Petr

    2011-01-01

    Roč. 108, č. 1 (2011), s. 203-207 ISSN 0027-8424 R&D Projects: GA MŠk LC06073 Institutional research plan: CEZ:AV0Z60050516 Keywords : biological invasions * Europe * economy Subject RIV: EF - Botanics Impact factor: 9.681, year: 2011

  1. On shelterbelt design for combating sand invasion.

    NARCIS (Netherlands)

    Mohammed, A.E.; Stigter, C.J.; Adam, H.S.

    1996-01-01

    After a review of the scarce literature on using trees against sand encroachment, a quantitative experiment with a wide shelterbelt to combat sand invasion is reported on. Experimental work was carried out at the northwestern border of the Gezira Scheme (Sudan), an area of severe land degradation

  2. Voriconazole salvage treatment of invasive candidiasis.

    NARCIS (Netherlands)

    Ostrosky-Zeichner, L.; Oude Lashof, A.M.L.; Kullberg, B.J.; Rex, J.H.

    2003-01-01

    Data on the salvage treatment of invasive candidiasis with voriconazole in 52 patients intolerant of other antifungal agents or with infection refractory to other antifungal agents were analyzed. Patients had received a mean of two previous antifungal agents (range, 1-4 agents), and 83% had received

  3. The Long American Grain Invasion of Britain

    DEFF Research Database (Denmark)

    Sharp, Paul Richard

    and Britain. Both trade statistics and contemporary comment reveal the importance of this trade from the middle to late eighteenth century, long before the so-called grain invasion of the late nineteenth century. Using data on imports from America and a large volume of substantiating primary evidence...

  4. Sonomammographic characteristics of invasive lobular carcinoma

    Directory of Open Access Journals (Sweden)

    El-Damshety O

    2012-07-01

    Full Text Available Osama R Kombar,1,3 Dalia M Fahmy,1 Mary V Brown,3 Omar Farouk,2 Osama El-Damshety21Diagnostic Radiology Department, 2Surgical Oncology Department, Oncology Center, Mansoura University, Mansoura, Egypt; 3Diagnostic Radiology Department, Al-Amiri Hospital, Safat, KuwaitObjective: The objective of our study was to identify characteristic features of invasive lobular carcinoma on mammography and ultrasound examinationsMaterials and methods: This is a retrospective multicenter study of women with biopsy-proven invasive lobular carcinoma. All patients had undergone diagnostic sonomammography. The imaging findings were identified by experienced breast imagers. Final surgical pathology results were used as the reference standard.Results: Thirty-two women ranging in age from 42 to 63 years old (mean age, 53 years, All had biopsy-proven invasive lobular carcinomas. Common features on mammogram included dense mass followed by architectural distortion; three cases showed breast asymmetry and one case was reported as normal. On ultrasound, common features included solid mass with spiculated margins, posterior shadowing, and perpendicular to the skin.Conclusion: Although no specific features could be linked to invasive lobular carcinoma, care should be directed to subtle signs such as architectural distortion and breast asymmetry in order not to miss any lesions. The combination of mammographic and sonographic helps to decrease the relatively high false negative diagnosis of this type of breast cancer.Keywords: mammography, ultrasound, cancer, breast

  5. Systems for tracking minimally invasive surgical instruments

    NARCIS (Netherlands)

    Chmarra, M. K.; Grimbergen, C. A.; Dankelman, J.

    2007-01-01

    Minimally invasive surgery (e.g. laparoscopy) requires special surgical skills, which should be objectively assessed. Several studies have shown that motion analysis is a valuable assessment tool of basic surgical skills in laparoscopy. However, to use motion analysis as the assessment tool, it is

  6. Invasive thymoma; Radiologic evaluation by computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Choon Sik; Choe, Kyu Ok [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    1985-04-15

    In 6 cases of invasive thymoma proved histologically from 1981 to 1984 in Yonsei University Medical Center, the CT findings and pattern were analysed. The results were as follows; 1. Of 6 cases, 4 were males and 2 were females. All cases were between 40-64 years and the average was 51 year old. 2. Of 6 cases, 2 female patients were associated with myasthenia gravis. 3. By the histological examination, 2 were confirmed as mixed cell type, 2 spindle cell type, 1 lymphocytic type and 1 epithelial cell type. 4. CT findings of invasive thymoma were 1) A discrete but lobulated and irregular marginated soft tissue mass in the superoanterior mediastinum replacing the normal mediastinal fat tissue. 2) Usually irregular low density areas within the mass suggesting central necrosis or calcification in 1 of 6 cases was noted. 3) Local invasiveness of the mass shown as obliteration of the normal fat plans surrounding great vessels, irregular thickening or nodular shadows of the pleura, diagphragm and pericardium and irregular and ragged tumor-lung interfaces if the tumor invade to the structures. 4) Frequent extension of tumor to middle and post. mediastinum along pericardium or mediastinal pleura with resultant extrinsic indentation and/or invasion of the hilar region. 5). Extensive tumor infiltration to middle and post. mediastinum in 1 case, indistinguishable from lymphoma. 6) Low attenuation numbered area of brain in another 1 case, but not confirmed histologically.

  7. New trends in minimally invasive urological surgery

    Directory of Open Access Journals (Sweden)

    Prabhakar Rajan

    2009-10-01

    Full Text Available Purpose: The perceived benefits of minimally-invasive surgery include less postoperative pain, shorter hospitalization, reduced morbidity and better cosmesis while maintaining diagnostic accuracy and therapeutic outcome. We review the new trends in minimally-invasive urological surgery. Materials and method: We reviewed the English language literature using the National Library of Medicine database to identify the latest technological advances in minimally-invasive surgery with particular reference to urology. Results: Amongst other advances, studies incorporating needlescopic surgery, laparoendoscopic single-site surgery , magnetic anchoring and guidance systems, natural orifice transluminal endoscopic surgery and flexible robots were considered of interest. The results from initial animal and human studies are also outlined. Conclusion: Minimally-invasive surgery continues to evolve to meet the demands of the operators and patients. Many novel technologies are still in the testing phase, whilst others have entered clinical practice. Further evaluation is required to confirm the safety and efficacy of these techniques and validate the published reports.

  8. Alien plant invasions in European woodlands

    NARCIS (Netherlands)

    Wagner, Viktoria; Chytrý, Milan; Jiménez-Alfaro, Borja; Pergl, Jan; Hennekens, Stephan; Biurrun, Idoia; Knollová, Ilona; Berg, Christian; Vassilev, Kiril; Rodwell, John S.; Škvorc, Željko; Jandt, Ute; Ewald, Jörg; Jansen, Florian; Tsiripidis, Ioannis; Botta-Dukát, Zoltán; Casella, Laura; Attorre, Fabio; Rašomavičius, Valerijus; Ćušterevska, Renata; Schaminée, Joop H.J.; Brunet, Jörg; Lenoir, Jonathan; Svenning, Jens Christian; Kącki, Zygmunt; Petrášová-Šibíková, Mária; Šilc, Urban; García-Mijangos, Itziar; Campos, Juan Antonio; Fernández-González, Federico; Wohlgemuth, Thomas; Onyshchenko, Viktor; Pyšek, Petr

    2017-01-01

    Aim: Woodlands make up a third of European territory and carry out important ecosystem functions, yet a comprehensive overview of their invasion by alien plants has never been undertaken across this continent. Location: Europe. Methods: We extracted data from 251,740 vegetation plots stored in the

  9. Minimally invasive treatments of uterine fibroids

    NARCIS (Netherlands)

    Voogt, M.J.

    2012-01-01

    This thesis assesses clinical results and technical developments of two minimally invasive treatments for symptomatic uterine fibroids: uterine artery embolization (UAE) and magnetic resonance-guided high intensity focused ultrasound (MR-HIFU). Part I: Uterine artery embolization The results of a

  10. Teaching Team Invasion Games and Motivational Climate

    Science.gov (United States)

    Gray, Shirley; Sproule, John; Morgan, Kevin

    2009-01-01

    Team invasion games (TIG) make up a large part of the PE curriculum in Scottish schools. It is important, therefore, to understand the environmental conditions that contribute to pupils' motivation to learn to play TIG. Consequently, this study aimed to identify the teaching behaviours exhibited when teaching TIG using a game-based approach and a…

  11. Non-muscle-invasive bladder cancer

    DEFF Research Database (Denmark)

    Malmström, Per-Uno; Agrawal, Sachin; Bläckberg, Mats

    2017-01-01

    The management of non-muscle-invasive bladder cancer (NMIBC) has evolved from the first reports on bladder endoscopy and transurethral resection to the introduction of adjuvant intravesical treatment. However, disease recurrence and progression remain an ongoing risk, placing a heavy burden...

  12. Control of invasive weeds with prescribed burning

    Science.gov (United States)

    DiTomaso, Joseph M.; Brooks, Matthew L.; Allen, Edith B.; Minnich, Ralph; Rice, Peter M.; Kyser, Guy B.

    2006-01-01

    Prescribed burning has primarily been used as a tool for the control of invasive late-season annual broadleaf and grass species, particularly yellow starthistle, medusahead, barb goatgrass, and several bromes. However, timely burning of a few invasive biennial broadleaves (e.g., sweetclover and garlic mustard), perennial grasses (e.g., bluegrasses and smooth brome), and woody species (e.g., brooms and Chinese tallow tree) also has been successful. In many cases, the effectiveness of prescribed burning can be enhanced when incorporated into an integrated vegetation management program. Although there are some excellent examples of successful use of prescribed burning for the control of invasive species, a limited number of species have been evaluated. In addition, few studies have measured the impact of prescribed burning on the long-term changes in plant communities, impacts to endangered plant species, effects on wildlife and insect populations, and alterations in soil biology, including nutrition, mycorrhizae, and hydrology. In this review, we evaluate the current state of knowledge on prescribed burning as a tool for invasive weed management.

  13. Invasive Bacterial Pathogens and their Antibiotic Susceptibility ...

    African Journals Online (AJOL)

    The isolates showed high rates of resistance to most antibiotics tested. The range of resistance for gram positive bacteria were 0% to 85.7%, and for gram negative from 0% to 100%. None of the isolates were resistance to ciprofloxacin and ceftriaxone. CONCLUSION: Our study result showed the presence of invasive ...

  14. Invasive species information networks: Collaboration at multiple scales for prevention, early detection, and rapid response to invasive alien species

    Science.gov (United States)

    Simpson, Annie; Jarnevich, Catherine S.; Madsen, John; Westbrooks, Randy G.; Fournier, Christine; Mehrhoff, Les; Browne, Michael; Graham, Jim; Sellers, Elizabeth A.

    2009-01-01

    Accurate analysis of present distributions and effective modeling of future distributions of invasive alien species (IAS) are both highly dependent on the availability and accessibility of occurrence data and natural history information about the species. Invasive alien species monitoring and detection networks (such as the Invasive Plant Atlas of New England and the Invasive Plant Atlas of the MidSouth) generate occurrence data at local and regional levels within the United States, which are shared through the US National Institute of Invasive Species Science. The Inter-American Biodiversity Information Network's Invasives Information Network (I3N), facilitates cooperation on sharing invasive species occurrence data throughout the Western Hemisphere. The I3N and other national and regional networks expose their data globally via the Global Invasive Species Information Network (GISIN). International and interdisciplinary cooperation on data sharing strengthens cooperation on strategies and responses to invasions. However, limitations to effective collaboration among invasive species networks leading to successful early detection and rapid response to invasive species include: lack of interoperability; data accessibility; funding; and technical expertise. This paper proposes various solutions to these obstacles at different geographic levels and briefly describes success stories from the invasive species information networks mentioned above. Using biological informatics to facilitate global information sharing is especially critical in invasive species science, as research has shown that one of the best indicators of the invasiveness of a species is whether it has been invasive elsewhere. Data must also be shared across disciplines because natural history information (e.g. diet, predators, habitat requirements, etc.) about a species in its native range is vital for effective prevention, detection, and rapid response to an invasion. Finally, it has been our

  15. A systematic review of context bias in invasion biology.

    Directory of Open Access Journals (Sweden)

    Robert J Warren

    Full Text Available The language that scientists use to frame biological invasions may reveal inherent bias-including how data are interpreted. A frequent critique of invasion biology is the use of value-laden language that may indicate context bias. Here we use a systematic study of language and interpretation in papers drawn from invasion biology to evaluate whether there is a link between the framing of papers and the interpretation of results. We also examine any trends in context bias in biological invasion research. We examined 651 peer-reviewed invasive species competition studies and implemented a rigorous systematic review to examine bias in the presentation and interpretation of native and invasive competition in invasion biology. We predicted that bias in the presentation of invasive species is increasing, as suggested by several authors, and that bias against invasive species would result in misinterpreting their competitive dominance in correlational observational studies compared to causative experimental studies. We indeed found evidence of bias in the presentation and interpretation of invasive species research; authors often introduced research with invasive species in a negative context and study results were interpreted against invasive species more in correlational studies. However, we also found a distinct decrease in those biases since the mid-2000s. Given that there have been several waves of criticism from scientists both inside and outside invasion biology, our evidence suggests that the subdiscipline has somewhat self-corrected apparent biases.

  16. A systematic review of context bias in invasion biology.

    Science.gov (United States)

    Warren, Robert J; King, Joshua R; Tarsa, Charlene; Haas, Brian; Henderson, Jeremy

    2017-01-01

    The language that scientists use to frame biological invasions may reveal inherent bias-including how data are interpreted. A frequent critique of invasion biology is the use of value-laden language that may indicate context bias. Here we use a systematic study of language and interpretation in papers drawn from invasion biology to evaluate whether there is a link between the framing of papers and the interpretation of results. We also examine any trends in context bias in biological invasion research. We examined 651 peer-reviewed invasive species competition studies and implemented a rigorous systematic review to examine bias in the presentation and interpretation of native and invasive competition in invasion biology. We predicted that bias in the presentation of invasive species is increasing, as suggested by several authors, and that bias against invasive species would result in misinterpreting their competitive dominance in correlational observational studies compared to causative experimental studies. We indeed found evidence of bias in the presentation and interpretation of invasive species research; authors often introduced research with invasive species in a negative context and study results were interpreted against invasive species more in correlational studies. However, we also found a distinct decrease in those biases since the mid-2000s. Given that there have been several waves of criticism from scientists both inside and outside invasion biology, our evidence suggests that the subdiscipline has somewhat self-corrected apparent biases.

  17. Economics of Harmful Invasive Species: A Review

    Directory of Open Access Journals (Sweden)

    George Marbuah

    2014-07-01

    Full Text Available The purpose of this study is to review theoretical and empirical findings in economics with respect to the challenging question of how to manage invasive species. The review revealed a relatively large body of literature on the assessment of damage costs of invasive species; single species and groups of species at different geographical scales. However, the estimated damage costs show large variation, from less than 1 million USD to costs corresponding to 12% of gross domestic product, depending on the methods employed, geographical scale, and scope with respect to inclusion of different species. Decisions regarding optimal management strategies, when to act in the invasion chain and which policy to choose, have received much less attention in earlier years, but have been subject to increasing research during the last decade. More difficult, but also more relevant policy issues have been raised, which concern the targeting in time and space of strategies under conditions of uncertainty. In particular, the weighting of costs and benefits from early detection and mitigation against the uncertain avoidance of damage with later control, when the precision in targeting species is typically greater is identified as a key challenge. The role of improved monitoring for detecting species and their spread and damage has been emphasized, but questions remain on how to achieve this in practice. This is in contrast to the relatively large body of literature on policies for mitigating dispersal by trade, which is regarded as one of the most important vectors for the spread of invasive species. On the other hand, the literature on how to mitigate established species, by control or adaptation, is much more scant. Studies evaluating causes for success or failure of policies against invasive in practice are in principal non-existing.

  18. From mini-invasive to non-invasive treatment using monopolar radiofrequency: the next orthopaedic frontier.

    Science.gov (United States)

    Whipple, Terry L

    2009-10-01

    Tendinopathy arises from a failed tendon healing process. Current non-invasive therapeutic alternatives are anti-inflammatory in nature, and outcomes are unpredictable. The benefit of invasive alternatives resides in the induction of the healing response. A new technology that uses non-invasive monopolar capacitive coupled radiofrequency has demonstrated the ability to raise temperatures in tendons and ligaments above 50 degrees C, the threshold for collagen modulation, tissue shrinkage and recruitment of macrophages, fibroblasts, and heat shock protein factors, without damaging the overlying structures, resulting in activation of the wound healing response. Monopolar capacitive-coupled radiofrequency offers a new non-invasive choice for tendinopathies and sprained ligaments. It does not interfere with subsequent surgical procedures should they become necessary.

  19. Reproductive characteristics of neophytes in the Czech Republic: traits of invasive and non-invasive species

    Czech Academy of Sciences Publication Activity Database

    Moravcová, Lenka; Pyšek, Petr; Jarošík, Vojtěch; Havlíčková, Vendula; Zákravský, Petr

    2010-01-01

    Roč. 82, č. 4 (2010), s. 365-390 ISSN 0032-7786 R&D Projects: GA MŠk LC06073; GA ČR GA206/09/0563; GA ČR GA206/05/0323 Institutional research plan: CEZ:AV0Z60050516 Keywords : plant invasions * reproductive traits * invasiveness Subject RIV: EF - Botanics Impact factor: 2.792, year: 2010

  20. Stress in biological invasions: Introduced invasive grey squirrels increase physiological stress in native Eurasian red squirrels.

    Science.gov (United States)

    Santicchia, Francesca; Dantzer, Ben; van Kesteren, Freya; Palme, Rupert; Martinoli, Adriano; Ferrari, Nicola; Wauters, Lucas Armand

    2018-05-23

    Invasive alien species can cause extinction of native species through processes including predation, interspecific competition for resources or disease-mediated competition. Increases in stress hormones in vertebrates may be associated with these processes and contribute to the decline in survival or reproduction of the native species. Eurasian red squirrels (Sciurus vulgaris) have gone extinct across much of the British Isles and parts of Northern Italy following the introduction of North American invasive grey squirrels (Sciurus carolinensis). We extracted glucocorticoid metabolites from faecal samples to measure whether the presence of the invasive species causes an increase in physiological stress in individuals of the native species. We show that native red squirrels in seven sites where they co-occurred with invasive grey squirrels had glucocorticoid concentrations that were three times higher than those in five sites without the invasive species. Moreover, in a longitudinal study, stress hormones in native red squirrels increased after colonisation by grey squirrels. When we experimentally reduced the abundance of the invasive grey squirrels, the concentration of faecal glucocorticoid metabolites in co-occurring red squirrels decreased significantly between pre- and postremoval periods. Hence, we found that the invasive species acts as a stressor which significantly increases the concentrations of glucocorticoids in the native species. Given that sustained elevations in glucocorticoids could reduce body growth and reproductive rate, our results are consistent with previous studies where the co-occurrence of the invasive grey squirrel was associated with smaller size and lower reproductive output in red squirrels. © 2018 The Authors. Journal of Animal Ecology © 2018 British Ecological Society.

  1. The effects of exotic weed Flaveria bidentis with different invasion ...

    African Journals Online (AJOL)

    Aghomotsegin

    community, especially its effect pattern at different invasion stages. In this study, soil ... invasion significantly decreased the richness of soil bacterial community, and the decline contents were positively ...... in nitrogen turnover. Agric. Ecosyst.

  2. School based assessment module for invasion games category in ...

    African Journals Online (AJOL)

    School based assessment module for invasion games category in physical education. ... This study identify the level of basic skills of invasion games category when using School Based Assessment Module. ... AJOL African Journals Online.

  3. CT evaluation of gastric cancer. Depth of tumor invasion and pancreas invasion

    International Nuclear Information System (INIS)

    Banba, Yoshihisa; Kanazawa, Tadayoshi; Seto, Hikaru

    1998-01-01

    To compare the internal structure of tumor and the contiguous organ configuration on computed tomography (CT) with the depth of tumor invasion on the pathological specimen. Sixty-four gastric cancers depicted on incremental dynamic CT were classified according to the internal structure of the tumor, and correlated with the depth of tumor invasion. In addition, the cancers were classified according to the contiguous pancreatic configuration, and correlated with the degree of pancreatic invasion. Eleven tumors with thickened gastric wall consisting of both a thick inner layer of high attenuation and a thin outer layer of low attenuation (two-layered tumor with a thin outer layer) did not invade the serosa: mucosa (n=5) and submucosa (n=6). Of 59 gastric cancers with a regular margin to the contiguous pancreas, pancreatic invasion was absent in 58 and present in one. Pancreatic invasion was present in all of five gastric cancers with an irregular margin. Our results indicate that two-layered gastric tumors with a thin outer layer never invade the serosa. Furthermore, pancreatic invasion is predicted only when the margin of the contiguous pancreas is irregular. (author)

  4. Invasive versus Non Invasive Methods Applied to Mummy Research: Will This Controversy Ever Be Solved?

    Science.gov (United States)

    Day, Jasmine; Bianucci, Raffaella

    2015-01-01

    Advances in the application of non invasive techniques to mummified remains have shed new light on past diseases. The virtual inspection of a corpse, which has almost completely replaced classical autopsy, has proven to be important especially when dealing with valuable museum specimens. In spite of some very rewarding results, there are still many open questions. Non invasive techniques provide information on hard and soft tissue pathologies and allow information to be gleaned concerning mummification practices (e.g., ancient Egyptian artificial mummification). Nevertheless, there are other fields of mummy studies in which the results provided by non invasive techniques are not always self-explanatory. Reliance exclusively upon virtual diagnoses can sometimes lead to inconclusive and misleading interpretations. On the other hand, several types of investigation (e.g., histology, paleomicrobiology, and biochemistry), although minimally invasive, require direct contact with the bodies and, for this reason, are often avoided, particularly by museum curators. Here we present an overview of the non invasive and invasive techniques currently used in mummy studies and propose an approach that might solve these conflicts. PMID:26345295

  5. Invasive Plant Species in the National Parks of Vietnam

    OpenAIRE

    Bernard Dell; Pham Quang Thu; Dang Thanh Tan

    2012-01-01

    The impact of invasive plant species in national parks and forests in Vietnam is undocumented and management plans have yet to be developed. Ten national parks, ranging from uncut to degraded forests located throughout Vietnam, were surveyed for invasive plant species. Transects were set up along roads, trails where local people access park areas, and also tracks through natural forest. Of 134 exotic weeds, 25 were classified as invasive species and the number of invasive species ranged from ...

  6. HPV genotypes in invasive cervical cancer in Danish women

    DEFF Research Database (Denmark)

    Kirschner, Benny; Junge, Jette; Holl, Katsiaryna

    2013-01-01

    Human papillomavirus (HPV) genotype distribution in invasive cervical cancers may differ by geographic region. The primary objective of this study was to estimate HPV-genotype distribution in Danish women with a diagnosis of invasive cervical cancer.......Human papillomavirus (HPV) genotype distribution in invasive cervical cancers may differ by geographic region. The primary objective of this study was to estimate HPV-genotype distribution in Danish women with a diagnosis of invasive cervical cancer....

  7. Invasive ductal carcinoma with lobular features: a comparison study to invasive ductal and invasive lobular carcinomas of the breast.

    Science.gov (United States)

    Arps, David P; Healy, Patrick; Zhao, Lili; Kleer, Celina G; Pang, Judy C

    2013-04-01

    Invasive ductal carcinoma with lobular features (IDC-L) is not recognized as a distinct subtype of breast cancer, and its clinicopathologic features and outcomes are unknown. In this retrospective study, we focused on characterization of clinicopathologic features and outcomes of IDC-L and compared them to invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC). 183 cases of IDC-L from 1996 to 2011 were compared with 1,499 cases of IDC and 375 cases of ILC. Available slides of IDC-L (n = 150) were reviewed to quantify the lobular component (≤ 20, 21-50, 51-80, >80 %), defined as small cells individually dispersed, arranged in linear cords, or in loose aggregates without the formation of tubules or cohesive nests. E-cadherin immunostain was performed to confirm ductal origin. Compared to IDC, IDC-L was more likely to have lower histologic grade (p lobular component in IDC-L had no impact on the size, nodal status, stage, or outcome. Our data suggest that although IDC-L may be a variant of IDC, with >90 % of cases being E-cadherin positive, the clinical and biological characteristics are more similar to that of ILC.

  8. Rocky Mountain Research Station invasive species visionary white paper

    Science.gov (United States)

    D. E. Pearson; M. Kim; J. Butler

    2011-01-01

    Invasive species represent one of the single greatest threats to natural ecosystems and the services they provide. Effectively addressing the invasive species problem requires management that is based on sound research. We provide an overview of recent and ongoing invasive species research conducted by Rocky Mountain Research Station scientists in the Intermountain...

  9. The role of hybridization in facilitating tree invasion

    Science.gov (United States)

    Hybridization events can generate additional genetic diversity on which natural selection can act and at times enhance invasiveness of the species. Invasive tree species are a growing ecological concern worldwide, and some of these invasions involve hybridization events pre- or post-introduction. Th...

  10. Tamarix (Tamaricaceae) hybrids: most dominant invasive genotype in southern Africa

    Science.gov (United States)

    Hybridization can potentially enhance invasiveness. Tamarix (Tamaricaceae) hybrids appear to be the dominant genotypes in their invasions. Exotic Tamarix are declared invasive in South Africa and the exotic T. chinensis and T. ramosissima are known to hybridize between themselves, and with the nativ...

  11. Invasion of exotic earthworms into ecosystems inhabited by native earthworms

    Science.gov (United States)

    P. F. Hendrix; G. H. Baker; M. A. Callaham Jr; G. A. Damoff; Fragoso C.; G. Gonzalez; S. W. James; S. L. Lachnicht; T. Winsome; X. Zou

    2006-01-01

    The most conspicuous biological invasions in terrestrial ecosystems have been by exotic plants, insects and vertebrates. Invasions by exotic earthworms, although not as well studied, may be increasing with global commerce in agriculture, waste management and bioremediation. A number of cases has documented where invasive earthworms have caused significant changes in...

  12. Optimal detection and control strategies for invasive species management

    Science.gov (United States)

    Shefali V. Mehta; Robert G. Haight; Frances R. Homans; Stephen Polasky; Robert C. Venette

    2007-01-01

    The increasing economic and environmental losses caused by non-native invasive species amplify the value of identifying and implementing optimal management options to prevent, detect, and control invasive species. Previous literature has focused largely on preventing introductions of invasive species and post-detection control activities; few have addressed the role of...

  13. The potential role of podoplanin in tumour invasion

    Science.gov (United States)

    Wicki, A; Christofori, G

    2006-01-01

    Podoplanin is a small mucin-like transmembrane protein, widely expressed in various specialised cell types throughout the body. Here, we revisit the mechanism of podoplanin-mediated tumour invasion. We compare molecular pathways leading to single and collective cell invasion and discuss novel distinct concepts of tumour cell invasion. PMID:17179989

  14. Does responsiveness to arbuscular mycorrhizas depend on plant invasive status?

    Science.gov (United States)

    1. Some posit invasive alien plants are less dependent on mycorrhizal associations than native plants, and thus weak mycorrhizal responsiveness may be a general mechanism of plant invasion. 2. Here, we tested whether mycorrhizal responsiveness varies by plant invasive status while controlling for ph...

  15. 49 CFR 801.56 - Unwarranted invasion of personal privacy.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Unwarranted invasion of personal privacy. 801.56... Unwarranted invasion of personal privacy. Pursuant to 5 U.S.C. 552(b)(6), any personal, medical, or similar... a clearly unwarranted invasion of the person's personal privacy. ...

  16. Invasive species unchecked by climate - response

    DEFF Research Database (Denmark)

    Burrows, Michael T.; Schoeman, David S.; Duarte, Carlos M.

    2012-01-01

    environments. This may be particularly true in the world's boreal oceans as melting sea ice facilitates new migratory passages between the Atlantic and Pacific Oceans. Moreover, as the ebb and flow of biodiversity intensifies under anthropogenic climate change, novel climates and communities of species......Hulme points out that observed rates of range expansion by invasive alien species are higher than the median speed of isotherm movement over the past 50 years, which in turn has outpaced the rates of climate-associated range changes of marine and terrestrial species. This is not surprising, given...... of climate-change-induced range shifts between native and alien species are meaningful only after the initial invasive spread has reached a stable range boundary. A focus on regions with high velocities of climate change, and on regions such as the tropics where novel thermal niches are being created, should...

  17. DNA barcoding of invasive plants in China: A resource for identifying invasive plants.

    Science.gov (United States)

    Xu, Song-Zhi; Li, Zhen-Yu; Jin, Xiao-Hua

    2018-01-01

    Invasive plants have aroused attention globally for causing ecological damage and having a negative impact on the economy and human health. However, it can be extremely challenging to rapidly and accurately identify invasive plants based on morphology because they are an assemblage of many different families and many plant materials lack sufficient diagnostic characteristics during border inspections. It is therefore urgent to evaluate candidate loci and build a reliable genetic library to prevent invasive plants from entering China. In this study, five common single markers (ITS, ITS2, matK, rbcL and trnH-psbA) were evaluated using 634 species (including 469 invasive plant species in China, 10 new records to China, 16 potentially invasive plant species around the world but not introduced into China yet and 139 plant species native to China) based on three different methods. Our results indicated that ITS2 displayed largest intra- and interspecific divergence (1.72% and 91.46%). Based on NJ tree method, ITS2, ITS, matK, rbcL and trnH-psbA provided 76.84%, 76.5%, 63.21%, 52.86% and 50.68% discrimination rates, respectively. The combination of ITS + matK performed best and provided 91.03% discriminatory power, followed by ITS2 + matK (85.78%). For identifying unknown individuals, ITS + matK had 100% correct identification rate based on our database, followed by ITS/ITS2 (both 93.33%) and ITS2 + matK (91.67%). Thus, we propose ITS/ITS2 + matK as the most suitable barcode for invasive plants in China. This study also demonstrated that DNA barcoding is an efficient tool for identifying invasive species. © 2017 John Wiley & Sons Ltd.

  18. Alien plant invasions in European woodlands

    Czech Academy of Sciences Publication Activity Database

    Wagner, V.; Chytrý, M.; Jiménez-Alfaro, B.; Pergl, Jan; Hennekens, S. M.; Biurrun, I.; Knollová, I.; Berg, C.; Vassilev, K.; Rodwell, J. S.; Škvorc, Ž.; Jandt, U.; Ewald, J.; Jansen, F.; Tsiripidis, I.; Botta-Dukát, Z.; Casella, L.; Attorre, F.; Rašomavičius, V.; Ćušterevska, R.; Schaminée, J.H.J.; Brunet, J.; Lenoir, J.; Svenning, J.-C.; Kacki, Z.; Petrášová-Šibíková, M.; Šilc, U.; García-Mijangos, I.; Campos, J. A.; Fernández-González, F.; Wohlgemuth, T.; Onyshchenko, V.; Pyšek, Petr

    2017-01-01

    Roč. 23, č. 9 (2017), s. 969-981 ISSN 1366-9516 R&D Projects: GA ČR GB14-36079G Grant - others:AV ČR(CZ) AP1002 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:67985939 Keywords : neophyte * non-native * invasive plants * EUNIS * forests Subject RIV: EH - Ecology, Behaviour OBOR OECD: Biodiversity conservation Impact factor: 4.391, year: 2016

  19. Procedures minimally invasive image-guided

    International Nuclear Information System (INIS)

    Mora Guevara, Alejandro

    2011-01-01

    A literature review focused on minimally invasive procedures, has been performed at the Department of Radiology at the Hospital Calderon Guardia. A multidisciplinary team has been raised for decision making. The materials, possible complications and the available imaging technique such as ultrasound, computed tomography, magnetic resonance imaging, have been determined according to the procedure to be performed. The revision has supported medical interventions didactically enjoying the best materials, resources and conditions for a successful implementation of procedures and results [es

  20. Minimally invasive aesthetic procedures in young adults

    OpenAIRE

    Wollina, Uwe; Goldman, Alberto

    2011-01-01

    Uwe Wollina1, Alberto Goldman21Department of Dermatology and Allergology, Academic Teaching Hospital Dresden-Friedrichstadt, Dresden, Germany; 2Clinica Goldman, Porto Alegre, Rio Grande du Sul, BrazilAbstract: Age is a significant factor in modifying specific needs when it comes to medical aesthetic procedures. In this review we will focus on young adults in their third decade of life and review minimally invasive aesthetic procedures other than cosmetics and cosmeceuticals. Correction of asy...

  1. Screening and Invasive Testing in Twins

    Directory of Open Access Journals (Sweden)

    Giovanni Monni

    2014-07-01

    Full Text Available Prenatal screening and testing for trisomy 21 in twin pregnancies poses a number of challenges: the exact estimate of the a priori risk of trisomy 21, the choice of prenatal screening test and/or invasive techniques to employ for the diagnosis and the impact of the result on the options of treatment in case of discordant results within a twin pair or among multiples. These different aspects are discussed below while recognizing that many issues remain unresolved.

  2. Minimally Invasive Surgery in Thymic Malignances

    Directory of Open Access Journals (Sweden)

    Wentao FANG

    2018-04-01

    Full Text Available Surgery is the most important therapy for thymic malignances. The last decade has seen increasing adoption of minimally invasive surgery (MIS for thymectomy. MIS for early stage thymoma patients has been shown to yield similar oncological results while being helpful in minimize surgical trauma, improving postoperative recovery, and reduce incisional pain. Meanwhile, With the advance in surgical techniques, the patients with locally advanced thymic tumors, preoperative induction therapies or recurrent diseases, may also benefit from MIS in selected cases.

  3. A Landscape Approach to Invasive Species Management.

    Directory of Open Access Journals (Sweden)

    Miguel Lurgi

    Full Text Available Biological invasions are not only a major threat to biodiversity, they also have major impacts on local economies and agricultural production systems. Once established, the connection of local populations into metapopulation networks facilitates dispersal at landscape scales, generating spatial dynamics that can impact the outcome of pest-management actions. Much planning goes into landscape-scale invasive species management. However, effective management requires knowledge on the interplay between metapopulation network topology and management actions. We address this knowledge gap using simulation models to explore the effectiveness of two common management strategies, applied across different extents and according to different rules for selecting target localities in metapopulations with different network topologies. These management actions are: (i general population reduction, and (ii reduction of an obligate resource. The reduction of an obligate resource was generally more efficient than population reduction for depleting populations at landscape scales. However, the way in which local populations are selected for management is important when the topology of the metapopulation is heterogeneous in terms of the distribution of connections among local populations. We tested these broad findings using real-world scenarios of European rabbits (Oryctolagus cuniculus infesting agricultural landscapes in Western Australia. Although management strategies targeting central populations were more effective in simulated heterogeneous metapopulation structures, no difference was observed in real-world metapopulation structures that are highly homogeneous. In large metapopulations with high proximity and connectivity of neighbouring populations, different spatial management strategies yield similar outcomes. Directly considering spatial attributes in pest-management actions will be most important for metapopulation networks with heterogeneously

  4. Sonomammographic characteristics of invasive lobular carcinoma

    OpenAIRE

    Fahmy, Dalia Monir; Kombar,; Farouk,Omar; El-damshety,; Brown,

    2012-01-01

    Osama R Kombar,1,3 Dalia M Fahmy,1 Mary V Brown,3 Omar Farouk,2 Osama El-Damshety21Diagnostic Radiology Department, 2Surgical Oncology Department, Oncology Center, Mansoura University, Mansoura, Egypt; 3Diagnostic Radiology Department, Al-Amiri Hospital, Safat, KuwaitObjective: The objective of our study was to identify characteristic features of invasive lobular carcinoma on mammography and ultrasound examinationsMaterials and methods: This is a retrospective multicenter study of women with ...

  5. Optic nerve invasion of uveal melanoma

    DEFF Research Database (Denmark)

    Lindegaard, Jens; Isager, Peter; Prause, Jan Ulrik

    2007-01-01

    in Denmark between 1942 and 2001 were reviewed (n=157). Histopathological characteristics and depth of optic nerve invasion were recorded. The material was compared with a control material from the same period consisting of 85 cases randomly drawn from all choroidal/ciliary body melanomas without optic nerve...... juxtapapillary tumors invading the optic nerve because of simple proximity to the nerve. A neurotropic subtype invades the optic nerve and retina in a diffuse fashion unrelated to tumor size or location. Udgivelsesdato: 2007-Jan...

  6. A Landscape Approach to Invasive Species Management.

    Science.gov (United States)

    Lurgi, Miguel; Wells, Konstans; Kennedy, Malcolm; Campbell, Susan; Fordham, Damien A

    2016-01-01

    Biological invasions are not only a major threat to biodiversity, they also have major impacts on local economies and agricultural production systems. Once established, the connection of local populations into metapopulation networks facilitates dispersal at landscape scales, generating spatial dynamics that can impact the outcome of pest-management actions. Much planning goes into landscape-scale invasive species management. However, effective management requires knowledge on the interplay between metapopulation network topology and management actions. We address this knowledge gap using simulation models to explore the effectiveness of two common management strategies, applied across different extents and according to different rules for selecting target localities in metapopulations with different network topologies. These management actions are: (i) general population reduction, and (ii) reduction of an obligate resource. The reduction of an obligate resource was generally more efficient than population reduction for depleting populations at landscape scales. However, the way in which local populations are selected for management is important when the topology of the metapopulation is heterogeneous in terms of the distribution of connections among local populations. We tested these broad findings using real-world scenarios of European rabbits (Oryctolagus cuniculus) infesting agricultural landscapes in Western Australia. Although management strategies targeting central populations were more effective in simulated heterogeneous metapopulation structures, no difference was observed in real-world metapopulation structures that are highly homogeneous. In large metapopulations with high proximity and connectivity of neighbouring populations, different spatial management strategies yield similar outcomes. Directly considering spatial attributes in pest-management actions will be most important for metapopulation networks with heterogeneously distributed links. Our

  7. Minimally invasive surgery for esophageal achalasia

    OpenAIRE

    Bonavina, Luigi

    2006-01-01

    Esophageal achalasia is the most commonly diagnosed primary esophageal motor disorder and the second most common functional esophageal disorder. Current therapy of achalasia is directed toward elimination of the outflow resistance caused by failure of the lower esophageal sphincter to relax completely upon swallowing. The advent of minimally invasive surgery has nearly replaced endoscopic pneumatic dilation as the first-line therapeutic approach. In this editorial, the rationale and the evide...

  8. Bacterial endophytes enhance competition by invasive plants.

    Science.gov (United States)

    Rout, Marnie E; Chrzanowski, Thomas H; Westlie, Tara K; DeLuca, Thomas H; Callaway, Ragan M; Holben, William E

    2013-09-01

    Invasive plants can alter soil microbial communities and profoundly alter ecosystem processes. In the invasive grass Sorghum halepense, these disruptions are consequences of rhizome-associated bacterial endophytes. We describe the effects of N2-fixing bacterial strains from S. halepense (Rout and Chrzanowski, 2009) on plant growth and show that bacteria interact with the plant to alter soil nutrient cycles, enabling persistence of the invasive. • We assessed fluxes in soil nutrients for ∼4 yr across a site invaded by S. halepense. We assayed the N2-fixing bacteria in vitro for phosphate solubilization, iron chelation, and production of the plant-growth hormone indole-3-acetic acid (IAA). We assessed the plant's ability to recruit bacterial partners from substrates and vertically transmit endophytes to seeds and used an antibiotic approach to inhibit bacterial activity in planta and assess microbial contributions to plant growth. • We found persistent alterations to eight biogeochemical cycles (including nitrogen, phosphorus, and iron) in soils invaded by S. halepense. In this context, three bacterial isolates solubilized phosphate, and all produced iron siderophores and IAA in vitro. In growth chamber experiments, bacteria were transmitted vertically, and molecular analysis of bacterial community fingerprints from rhizomes indicated that endophytes are also horizontally recruited. Inhibiting bacterial activity with antibiotics resulted in significant declines in plant growth rate and biomass, with pronounced rhizome reductions. • This work suggests a major role of endophytes on growth and resource allocation of an invasive plant. Indeed, bacterial isolate physiology is correlated with invader effects on biogeochemical cycles of nitrogen, phosphate, and iron.

  9. Invasive plants on disturbed Korean sand dunes

    Science.gov (United States)

    Kim, Kee Dae

    2005-01-01

    The sand dunes in coastal regions of South Korea are important ecosystems because of their small size, the rare species found in this habitat, and the beautiful landscapes they create. This study investigated the current vegetative status of sand dunes on three representative coasts of the Korean peninsula, and on the coasts of Cheju Island, and assessed the conditions caused by invasive plants. The relationships between the degree of invasion and 14 environmental variables were studied. Plots of sand dunes along line transects perpendicular to the coastal lines were established to estimate vegetative species coverage. TWINSPAN (Two-Way Indicator Species Analysis), CCA (Canonical Correspondence Analysis), and DCCA (Detrended Canonical Correspondence Analysis) were performed to classify communities on sand dunes and assess species composition variation. Carex kobomugi, Elymus mollis, and Vitex rotundifolia were found to be the dominant species plotted on the east, the west, and the peripheral coasts of Cheju Island, respectively. Vegetation on the south coast was totally extinct. The 19 communities, including representative C. kobomugi, C. kobomugi- Ixeris repens, C. kobomugi- Oenothera biennis, E. mollis, Lolium multiflorum- Calystegia soldanella, and V. rotundifolia- C. kobomugi, were all classified according to TWINSPAN. Oenothera biennis and L. multiflorum were exotics observed within these native communities. CCA showed that invasive native and exotic species distribution was segregated significantly, according to disturbance level, exotic species number, gravel, sand and silt contents, as well as vegetation size. It further revealed that human disturbance can strongly favor the settlement of invasive and exotic species. Restoration options to reduce exotic plants in the South Korean sand dune areas were found to be the introduction of native plant species from one sand dune into other sand dune areas, prohibition of building and the introduction of exotic

  10. Intensive care unit audit: invasive procedure surveillance

    Directory of Open Access Journals (Sweden)

    Mariama Amaral Michels

    2013-01-01

    Full Text Available Rationale and objective: currently, Healthcare-associated Infections (HAIs constitute a serious public health problem. It is estimated that for every ten hospitalized patients, one will have infection after admission, generating high costs resulting from increased length of hospitalization, additional diagnostic and therapeutic interventions. The intensive care unit (ICU, due to its characteristics, is one of the most complex units of the hospital environment, a result of the equipment, the available technology, the severity of inpatients and the invasive procedures the latter are submitted to. The aim of the study was to evaluate the adherence to specifi c HAI prevention measures in invasive ICU procedures. Methods: This study had a quantitative, descriptive and exploratory approach. Among the risk factors for HAIs are the presence of central venous access, indwelling vesical catheter and mechanical ventilation, and, therefore, the indicators were calculated for patients undergoing these invasive procedures, through a questionnaire standardized by the Hospital Infection Control Commission (HICC. Results: For every 1,000 patients, 15 had catheter-related bloodstream infection, 6.85 had urinary tract infection associated with indwelling catheter in the fi rst half of 2010. Conclusion: most HAIs cannot be prevented, for reasons inherent to invasive procedures and the patients. However, their incidence can be reduced and controlled. The implementation of preventive measures based on scientifi c evidence can reduce HAIs signifi cantly and sustainably, resulting in safer health care services and reduced costs. The main means of prevention include the cleaning of hands, use of epidemiological block measures, when necessary, and specifi c care for each infection site. KEYWORDS Nosocomial infection. Intensive care units.

  11. THE INVASIVE COLEOPTEROFAUNA FOR REPUBLIC OF MOLDOVA

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    Asea M. Timuş

    2015-07-01

    Full Text Available The invasive coleopterofauna for Republic of Moldova consists of the 100 species. After correlation local database with Fauna Europaea for our country registered are 31 of species, but for 69 mentioned with the „absent” and 38 „no date”. In the meantime 24 species were recorded for our country: Acanthoscelides abtectus, A.pallidipennis, Alphitobius diaperinus, Alphitophagus bifasciatus, Bruchus pisorum, B.rufimanus, Caulophilus latinasus, Diabrotica virgifera, Gnathocerus cornutus, Harmonia axyridis, Lasioderma serricorne, Leptinotarsa decemlineata, Lignyodes bischoffi, Lithocharis nigriceps, Oryzaephilus surinamensis, Rhyzopertha dominica, Sitophilus granarius, S. oryzae, S. zeamais, Tenebrio molitor, Tenebrioides mauritanicus, Tribolium castaneum, T. destructor, Trogoderma granarium. According periods penetration the invasive beetles it was found that 2 species have entered the XVIII century, 16 species in the XIX, 53 species in the XX and 29 species in the XXI century. The registration invasive beetles in countries of interest to the our country is in: Bulgaria – 54 species; Poland – 39; România – 3; other countries- 4.

  12. Mechanisms of cellular invasion by intracellular parasites.

    Science.gov (United States)

    Walker, Dawn M; Oghumu, Steve; Gupta, Gaurav; McGwire, Bradford S; Drew, Mark E; Satoskar, Abhay R

    2014-04-01

    Numerous disease-causing parasites must invade host cells in order to prosper. Collectively, such pathogens are responsible for a staggering amount of human sickness and death throughout the world. Leishmaniasis, Chagas disease, toxoplasmosis, and malaria are neglected diseases and therefore are linked to socio-economical and geographical factors, affecting well-over half the world's population. Such obligate intracellular parasites have co-evolved with humans to establish a complexity of specific molecular parasite-host cell interactions, forming the basis of the parasite's cellular tropism. They make use of such interactions to invade host cells as a means to migrate through various tissues, to evade the host immune system, and to undergo intracellular replication. These cellular migration and invasion events are absolutely essential for the completion of the lifecycles of these parasites and lead to their for disease pathogenesis. This review is an overview of the molecular mechanisms of protozoan parasite invasion of host cells and discussion of therapeutic strategies, which could be developed by targeting these invasion pathways. Specifically, we focus on four species of protozoan parasites Leishmania, Trypanosoma cruzi, Plasmodium, and Toxoplasma, which are responsible for significant morbidity and mortality.

  13. [Non-invasive assessment of fatty liver].

    Science.gov (United States)

    Egresi, Anna; Lengyel, Gabriella; Hagymási, Krisztina

    2015-04-05

    As the result of various harmful effects (infectious agents, metabolic diseases, unhealthy diet, obesity, toxic agents, autoimmune processes) hepatic damage may develop, which can progress towards liver steatosis, and fibrosis as well. The most common etiological factors of liver damages are hepatitis B and C infection, alcohol consumption and non-alcoholic fatty liver disease. Liver biopsy is considered as the gold standard for the diagnosis of chronic liver diseases. Due to the dangers and complications of liver biopsy, studies are focused on non-invasive markers and radiological imaging for liver steatosis, progression of fatty liver, activity of the necroinflammation and the severity of the fibrosis. Authors review the possibilities of non-invasive assessment of liver steatosis. The statistical features of the probes (positive, negative predictive values, sensitivity, specificity) are reviewed. The role of radiological imaging is also discussed. Although the non-invasive methods discussed in this article are useful to assess liver steatosis, further studies are needed to validate to follow progression of the diseases and to control therapeutic response.

  14. CT diagnosis of invasive hydatidiform mole

    International Nuclear Information System (INIS)

    Lu Mingquan; Jiang Lina; Li Xianxing; Wang Peijun

    2000-01-01

    Objective: To investigate the CT features and the diagnostic value in invasive mole. Methods: Eleven cases (age, 30 to 53 years, mean 40 years) with invasive mole proved by operation and pathology were studied, including 3 cases during peri-menopausal period of eight months, ten months and twelve months respectively. All cases were scanned by CT and enhanced study was done. Results: All cases showed enlargement of uterus of varying degrees. On CT, the density of uterine cavity was similar to that of water, intermingled with spotty patchy and hazy circular isodense shadows. High density stripe-like bleeding foci were found in 3 cases. The outline of uterine cavity was locally disrupted in all case and the muscle layer was thickened in 3 cases. On enhanced CT scan, the lesions in the uterine cavity appeared markedly hyperdense, just like 'the crater' and the 'mole sign'. The muscle layers at the site of disruption showed inhomogeneous enhancement after contrast injection. Conclusion: The CT features of invasive mole are characteristic, with important diagnostic value, especially for those during peri-menopausal period

  15. Thymoma and minimally invasive surgical treatment

    International Nuclear Information System (INIS)

    Krajc, T.; Spalek, P.; Lucenic, M.; Benej, R.; Harustiak, S.

    2011-01-01

    The authors review the current thymoma classification schemes, diagnosis and surgical treatment options. Many minimally invasive techniques do not provide sufficient extensiveness when compared to complete sternotomy. The Zieliński technique combines transcervical, subxiphoidal and bilateral thoracoscopic approach in a hybrid procedure (MMIT, maximal minimally invasive thymectomy) based on double sternal traction, and allows for removal of the thymus gland, the thymoma and all the relevant mediastinal adipose tissue, thus adhering to principles of oncological radicality. Of the 28 patients undergoing MMIT there were 7 with myasthenia associated thymoma (MGAT) and 5 with a thymoma and no myasthenia, tumors staged Masaoka I-II. Apart from one temporary recurrent nerve palsy there were no postoperative complications. The largest thymoma measured 70 x 65 x 55 mm. Adjuvant radiotherapy was applied in 5 patients. Ectopic thymic tissue was identified in 100 % of patients with thymoma and no myasthenia and in 42.9 % of MGAT patients. Until now there were no recurrences, however, the follow-up median is very short, the longest follow-up period being 30 months. MMIT is a safe technique suitable also for Masaoka I-II thymoma patients and for some specific cases with Masaoka III stage (lung parenchyma invasion). The authors approach all the anterior mediastinal tumors with no mediastinal lymphadenopathy and no myasthenia as a potential thymoma and always attempt the MMIT procedure starting as VATS procedure on the side of tumor. (author)

  16. Invasive aquarium fish transform ecosystem nutrient dynamics

    Science.gov (United States)

    Capps, Krista A.; Flecker, Alexander S.

    2013-01-01

    Trade of ornamental aquatic species is a multi-billion dollar industry responsible for the introduction of myriad fishes into novel ecosystems. Although aquarium invaders have the potential to alter ecosystem function, regulation of the trade is minimal and little is known about the ecosystem-level consequences of invasion for all but a small number of aquarium species. Here, we demonstrate how ecological stoichiometry can be used as a framework to identify aquarium invaders with the potential to modify ecosystem processes. We show that explosive growth of an introduced population of stoichiometrically unique, phosphorus (P)-rich catfish in a river in southern Mexico significantly transformed stream nutrient dynamics by altering nutrient storage and remineralization rates. Notably, changes varied between elements; the P-rich fish acted as net sinks of P and net remineralizers of nitrogen. Results from this study suggest species-specific stoichiometry may be insightful for understanding how invasive species modify nutrient dynamics when their population densities and elemental composition differ substantially from native organisms. Risk analysis for potential aquarium imports should consider species traits such as body stoichiometry, which may increase the likelihood that an invasion will alter the structure and function of ecosystems. PMID:23966642

  17. Competitive interactions between co-occurring invaders: identifying asymmetries between two invasive crayfish species

    NARCIS (Netherlands)

    Hudina, S.; Galic, N.G.; Roessink, I.; Hock, K.

    2011-01-01

    Ecosystems today increasingly suffer invasions by multiple invasive species. Complex interactions between invasive species can have different fitness implications for each invader, which can in turn determine the future progression of their invasions and result in differential impacts on native

  18. Dynamic models in research and management of biological invasions.

    Science.gov (United States)

    Buchadas, Ana; Vaz, Ana Sofia; Honrado, João P; Alagador, Diogo; Bastos, Rita; Cabral, João A; Santos, Mário; Vicente, Joana R

    2017-07-01

    Invasive species are increasing in number, extent and impact worldwide. Effective invasion management has thus become a core socio-ecological challenge. To tackle this challenge, integrating spatial-temporal dynamics of invasion processes with modelling approaches is a promising approach. The inclusion of dynamic processes in such modelling frameworks (i.e. dynamic or hybrid models, here defined as models that integrate both dynamic and static approaches) adds an explicit temporal dimension to the study and management of invasions, enabling the prediction of invasions and optimisation of multi-scale management and governance. However, the extent to which dynamic approaches have been used for that purpose is under-investigated. Based on a literature review, we examined the extent to which dynamic modelling has been used to address invasions worldwide. We then evaluated how the use of dynamic modelling has evolved through time in the scope of invasive species management. The results suggest that modelling, in particular dynamic modelling, has been increasingly applied to biological invasions, especially to support management decisions at local scales. Also, the combination of dynamic and static modelling approaches (hybrid models with a spatially explicit output) can be especially effective, not only to support management at early invasion stages (from prevention to early detection), but also to improve the monitoring of invasion processes and impact assessment. Further development and testing of such hybrid models may well be regarded as a priority for future research aiming to improve the management of invasions across scales. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Five potential consequences of climate change for invasive species.

    Science.gov (United States)

    Hellmann, Jessica J; Byers, James E; Bierwagen, Britta G; Dukes, Jeffrey S

    2008-06-01

    Scientific and societal unknowns make it difficult to predict how global environmental changes such as climate change and biological invasions will affect ecological systems. In the long term, these changes may have interacting effects and compound the uncertainty associated with each individual driver. Nonetheless, invasive species are likely to respond in ways that should be qualitatively predictable, and some of these responses will be distinct from those of native counterparts. We used the stages of invasion known as the "invasion pathway" to identify 5 nonexclusive consequences of climate change for invasive species: (1) altered transport and introduction mechanisms, (2) establishment of new invasive species, (3) altered impact of existing invasive species, (4) altered distribution of existing invasive species, and (5) altered effectiveness of control strategies. We then used these consequences to identify testable hypotheses about the responses of invasive species to climate change and provide suggestions for invasive-species management plans. The 5 consequences also emphasize the need for enhanced environmental monitoring and expanded coordination among entities involved in invasive-species management.

  20. Modelling Hotspots for Invasive Alien Plants in India.

    Science.gov (United States)

    Adhikari, Dibyendu; Tiwary, Raghuvar; Barik, Saroj Kanta

    2015-01-01

    Identification of invasion hotspots that support multiple invasive alien species (IAS) is a pre-requisite for control and management of invasion. However, till recently it remained a methodological challenge to precisely determine such invasive hotspots. We identified the hotspots of alien species invasion in India through Ecological Niche Modelling (ENM) using species occurrence data from the Global Biodiversity Information Facility (GBIF). The predicted area of invasion for selected species were classified into 4 categories based on number of model agreements for a region i.e. high, medium, low and very low. About 49% of the total geographical area of India was predicted to be prone to invasion at moderate to high levels of climatic suitability. The intersection of anthropogenic biomes and ecoregions with the regions of 'high' climatic suitability was classified as hotspot of alien plant invasion. Nineteen of 47 ecoregions of India, harboured such hotspots. Most ecologically sensitive regions of India, including the 'biodiversity hotspots' and coastal regions coincide with invasion hotspots, indicating their vulnerability to alien plant invasion. Besides demonstrating the usefulness of ENM and open source data for IAS management, the present study provides a knowledge base for guiding the formulation of an effective policy and management strategy for controlling the invasive alien species.

  1. Characterizing the landscape dynamics of an invasive plant and risk of invasion using remote sensing.

    Science.gov (United States)

    Bradley, Bethany A; Mustard, John F

    2006-06-01

    Improved understanding of the spatial dynamics of invasive plant species may lead to more effective land management and reduced future invasion. Here, we identified the spatial extents of nonnative cheatgrass (Bromus tectorum) in the north central Great Basin using remotely sensed data from Landsat MSS, TM, and ETM+. We compared cheatgrass extents in 1973 and 2001 to six spatially explicit landscape variables: elevation, aspect, hydrographic channels, cultivation, roads, and power lines. In 2001, Cheatgrass was 10% more likely to be found in elevation ranges from 1400 to 1700 m (although the data suggest a preferential invasion into lower elevations by 2001), 6% more likely on west and northwest facing slopes, and 3% more likely within hydrographic channels. Over this time period, cheatgrass expansion was also closely linked to proximity to land use. In 2001, cheatgrass was 20% more likely to be found within 3 km of cultivation, 13% more likely to be found within 700 m of a road, and 15% more likely to be found within 1 km of a power line. Finally, in 2001 cheatgrass was 26% more likely to be present within 150 m of areas occupied by cheatgrass in 1973. Using these relationships, we created a risk map of future cheatgrass invasion that may aid land management. These results highlight the importance of including land use variables and the extents of current plant invasion in predictions of future risk.

  2. Invasive earthworms interact with abiotic conditions to influence the invasion of common buckthorn (Rhamnus cathartica).

    Science.gov (United States)

    Roth, Alexander M; Whitfeld, Timothy J S; Lodge, Alexandra G; Eisenhauer, Nico; Frelich, Lee E; Reich, Peter B

    2015-05-01

    Common buckthorn (Rhamnus cathartica L.) is one of the most abundant and ecologically harmful non-native plants in forests of the Upper Midwest United States. At the same time, European earthworms are invading previously glaciated areas in this region, with largely anecdotal evidence suggesting they compound the negative effects of buckthorn and influence the invasibility of these forests. Germination and seedling establishment are important control points for colonization by any species, and manipulation of the conditions influencing these life history stages may provide insight into why invasive species are successful in some environments and not others. Using a greenhouse microcosm experiment, we examined the effects of important biotic and abiotic factors on the germination and seedling establishment of common buckthorn. We manipulated light levels, leaf litter depth and earthworm presence to investigate the independent and interactive effects of these treatments on buckthorn establishment. We found that light and leaf litter depth were significant predictors of buckthorn germination but that the presence of earthworms was the most important factor; earthworms interacted with light and leaf litter to increase the number and biomass of buckthorn across all treatments. Path analysis suggested both direct and moisture-mediated indirect mechanisms controlled these processes. The results suggest that the action of earthworms may provide a pathway through which buckthorn invades forests of the Upper Midwest United States. Hence, researchers and managers should consider co-invasion of plants and earthworms when investigating invasibility and creating preemptive or post-invasion management plans.

  3. MicroRNA and protein profiles in invasive versus non-invasive oral tongue squamous cell carcinoma cells in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Korvala, Johanna, E-mail: johanna.korvala@oulu.fi [Cancer and Translational Medicine Research Unit, University of Oulu, The Medical Research Center Oulu, Oulu University Hospital, Aapistie 5A, 90014 Oulu (Finland); Jee, Kowan [Department of Pathology, University of Turku, Turku University Hospital, Turku (Finland); Department of Pathology, Haartman Institute, University of Helsinki, Helsinki (Finland); Porkola, Emmi [Cancer and Translational Medicine Research Unit, University of Oulu, The Medical Research Center Oulu, Oulu University Hospital, Aapistie 5A, 90014 Oulu (Finland); Almangush, Alhadi [Department of Pathology, Haartman Institute, University of Helsinki, Helsinki (Finland); Mosakhani, Neda [Department of Pathology, HUSLAB, Helsinki (Finland); Bitu, Carolina [Cancer and Translational Medicine Research Unit, University of Oulu, The Medical Research Center Oulu, Oulu University Hospital, Aapistie 5A, 90014 Oulu (Finland); Cervigne, Nilva K. [Department of Oral Diagnosis, School of Dentistry, University of Campinas (UNICAMP), Av. Limeira, 901 – Bairro Areião, CEP: 13414-903 Piracicaba, São Paulo (Brazil); Department of Clinical and Pathology, Faculty of Medicine of Jundiai - FMJ, Jundiai, SP (Brazil); Zandonadi, Flávia S.; Meirelles, Gabriela V.; Leme, Adriana Franco Paes [Laboratório Nacional de Biociências, LNBio, CNPEM, Rua Giuseppe Máximo Scolfaro, 10.000, Polo II de Alta Tecnologia de Campinas, Campinas/SP, P.O.Box 6192, CEP 13083-970 Campinas, São Paulo (Brazil); Coletta, Ricardo D. [Department of Oral Diagnosis, School of Dentistry, University of Campinas (UNICAMP), Av. Limeira, 901 – Bairro Areião, CEP: 13414-903 Piracicaba, São Paulo (Brazil); and others

    2017-01-01

    Complex molecular pathways regulate cancer invasion. This study overviewed proteins and microRNAs (miRNAs) involved in oral tongue squamous cell carcinoma (OTSCC) invasion. The human highly aggressive OTSCC cell line HSC-3 was examined in a 3D organotypic human leiomyoma model. Non-invasive and invasive cells were laser-captured and protein expression was analyzed using mass spectrometry-based proteomics and miRNA expression by microarray. In functional studies the 3D invasion assay was replicated after silencing candidate miRNAs, miR-498 and miR-940, in invasive OTSCC cell lines (HSC-3 and SCC-15). Cell migration, proliferation and viability were also studied in the silenced cells. In HSC-3 cells, 67 proteins and 53 miRNAs showed significant fold-changes between non-invasive vs. invasive cells. Pathway enrichment analyses allocated “Focal adhesion” and “ECM-receptor interaction” as most important for invasion. Significantly, in HSC-3 cells, miR-498 silencing decreased the invasion area and miR-940 silencing reduced invasion area and depth. Viability, proliferation and migration weren’t significantly affected. In SCC-15 cells, down-regulation of miR-498 significantly reduced invasion and migration. This study shows HSC-3 specific miRNA and protein expression in invasion, and suggests that miR-498 and miR-940 affect invasion in vitro, the process being more influenced by mir-940 silencing in aggressive HSC-3 cells than in the less invasive SCC-15.

  4. Insights into invasion and restoration ecology: Time to collaborate towards a holistic approach to tackle biological invasions

    Directory of Open Access Journals (Sweden)

    Mirijam Gaertner

    2012-02-01

    Full Text Available The aim of our study is to provide an integrated framework for the management of alien plant invasions, combining insights and experiences from the fields of invasion and restoration ecology to enable more effective management of invasive species. To determine linkages between the scientific outputs of the two disciplines we used an existing data base on restoration studies between 2000 and 2008 and did a bibliometric analysis. We identified the type of restoration applied, determined by the aim of the study, and conducted a content analysis on 208 selected studies with a link to biological invasions (invasion-restoration studies. We found a total of 1075 articles on ecosystem restoration, with only eight percent of the studiesthe main objective to control alien invasions. The content analysis of 208 invasion-restoration studies showed that the majority of the studies focused on causes of degradation other than alien invasions. If invaders were referred to as the main driver of degradation, the prevalent cause for degradation was invaders outcompeting and replacing native species. Mechanical control of alien plant invasions was by far the most common control method used. Measures that went beyond the removal of alien plants were implemented in sixty-five percent of the studies.Although invasion control was not as common as other types of restoration, a closer look at the sub-group of invasion-restoration studies shows a clear link between restoration and invasion ecology. Concerns, as identified in the literature review, are firstly that restoration activities mostly focus on controlling the invader while other underlying causes for degradation are neglected, and secondly that the current approach of dealing with alien invasions lacks a combination of theoretical and practical aspects. We suggest that closer collaboration between invasion and restoration ecologists can help to improve the management of alien plant invasions. We conclude with a

  5. Invasion Success by Plant Breeding Evolutionary Changes as a Critical Factor for the Invasion of the Ornamental Plant Mahonia aquifolium

    CERN Document Server

    Ross, Christel Anne

    2009-01-01

    Invasive species are a major threat to global biodiversity and cause significant economic costs. Studying biological invasions is both essential for preventing future invasions and is also useful in order to understand basic ecological processes. Christel Ross investigates whether evolutionary changes by plant breeding are a relevant factor for the invasion success of Mahonia aquifolium in Germany. Her findings show that invasive populations differ from native populations in quantitative-genetic traits and molecular markers, whereas their genetic diversity is similar. She postulates that these evolutionary changes are rather a result of plant breeding, which includes interspecific hybridisation, than the result of a genetic bottleneck or the releases from specialist herbivores.

  6. Aplicación del bioensayo EROD-H4IIE para la determinación de dioxinas en carnes de pollos broiler: un estudio de equivalencia con la cromatografía de gases de alta resolución acoplada a espectrometría de masas de alta resolución

    OpenAIRE

    Schoffer, JT; Bustos-López, C; Sotomayor, P; Mattar, CA; González, A; Robles, C; Samsing, F; Acevedo, O; Valdovinos, CE

    2011-01-01

    En el presente estudio se aplicó el bioensayo EROD con línea celular H4IIE para determinar la equivalencia de resultados para carnes de pollo, entre el bioensayo EROD-H4IIE en pg TCDD-EQ/g de tejido y los resultados de la cromatografía de gases de alta resolución acoplada a espectrometría de alta resolución (HRGC/HRMS) en pg WHO-TEQ/g de grasa. Para lo anterior se utilizaron 41 muestras compuestas de trutros de pollo. Éstas fueron obtenidas en la planta faenadora de 4 planteles diferentes de ...

  7. A first step in understanding an invasive weed through its genes: an EST analysis of invasive Centaurea maculosa

    Directory of Open Access Journals (Sweden)

    He Ji

    2007-05-01

    Full Text Available Abstract Background The economic and biological implications of plant invasion are overwhelming; however, the processes by which plants become successful invaders are not well understood. Limited genetic resources are available for most invasive and weedy species, making it difficult to study molecular and genetic aspects that may be associated with invasion. Results As an initial step towards understanding the molecular mechanisms by which plants become invasive, we have generated a normalized Expressed Sequence Tag (EST library comprising seven invasive populations of Centaurea maculosa, an invasive aster in North America. Seventy-seven percent of the 4423 unique transcripts showed significant similarity to existing proteins in the NCBI database and could be grouped based on gene ontology assignments. Conclusion The C. maculosa EST library represents an initial step towards looking at gene-specific expression in this species, and will pave the way for creation of other resources such as microarray chips that can help provide a view of global gene expression in invasive C. maculosa and its native counterparts. To our knowledge, this is the first published set of ESTs derived from an invasive weed that will be targeted to study invasive behavior. Understanding the genetic basis of evolution for increased invasiveness in exotic plants is critical to understanding the mechanisms through which exotic invasions occur.

  8. A first step in understanding an invasive weed through its genes: an EST analysis of invasive Centaurea maculosa.

    Science.gov (United States)

    Broz, Amanda K; Broeckling, Corey D; He, Ji; Dai, Xinbin; Zhao, Patrick X; Vivanco, Jorge M

    2007-05-24

    The economic and biological implications of plant invasion are overwhelming; however, the processes by which plants become successful invaders are not well understood. Limited genetic resources are available for most invasive and weedy species, making it difficult to study molecular and genetic aspects that may be associated with invasion. As an initial step towards understanding the molecular mechanisms by which plants become invasive, we have generated a normalized Expressed Sequence Tag (EST) library comprising seven invasive populations of Centaurea maculosa, an invasive aster in North America. Seventy-seven percent of the 4423 unique transcripts showed significant similarity to existing proteins in the NCBI database and could be grouped based on gene ontology assignments. The C. maculosa EST library represents an initial step towards looking at gene-specific expression in this species, and will pave the way for creation of other resources such as microarray chips that can help provide a view of global gene expression in invasive C. maculosa and its native counterparts. To our knowledge, this is the first published set of ESTs derived from an invasive weed that will be targeted to study invasive behavior. Understanding the genetic basis of evolution for increased invasiveness in exotic plants is critical to understanding the mechanisms through which exotic invasions occur.

  9. Synergistic impacts by an invasive amphipod and an invasive fish explain native gammarid extinction.

    Science.gov (United States)

    Beggel, S; Brandner, J; Cerwenka, A F; Geist, J

    2016-07-14

    Worldwide freshwater ecosystems are increasingly affected by invasive alien species. In particular, Ponto-Caspian gobiid fishes and amphipods are suspected to have pronounced effects on aquatic food webs. However, there is a lack of systematic studies mechanistically testing the potential synergistic effects of invasive species on native fauna. In this study we investigated the interrelations between the invasive amphipod Dikerogammarus villosus and the invasive fish species Neogobius melanostomus in their effects on the native amphipod Gammarus pulex. We hypothesized selective predation by the fish as a driver for displacement of native species resulting in potential extinction of G. pulex. The survival of G. pulex in the presence of N. melanostomus in relation to the presence of D. villosus and availability of shelter was analyzed in the context of behavioural differences between the amphipod species. Gammarus pulex had a significantly higher susceptibility to predation by N. melanostomus compared to D. villosus in all experiments, suggesting preferential predation by this fish on native gammarids. Furthermore, the presence of D. villosus significantly increased the vulnerability of G. pulex to fish predation. Habitat structure was an important factor for swimming activity of amphipods and their mortality, resulting in a threefold decrease in amphipods consumed with shelter habitat structures provided. Behavioral differences in swimming activity were additionally responsible for higher predation rates on G. pulex. Intraguild predation could be neglected within short experimental durations. The results of this study provide evidence for synergistic effects of the two invasive Ponto-Caspian species on the native amphipod as an underlying process of species displacements during invasion processes. Prey behaviour and monotonous habitat structures additionally contribute to the decline of the native gammarid fauna in the upper Danube River and elsewhere.

  10. Secondary invasions of noxious weeds associated with control of invasive Tamarix are frequent, idiosyncratic and persistent

    Science.gov (United States)

    González, Eduardo; Sher, Anna A.; Anderson, Robert M.; Bay, Robin F.; Bean, Daniel W.; Bissonnete, Gabriel J.; Cooper, David J.; Dohrenwend, Kara; Eichhorst, Kim D.; El Waer, Hisham; Kennard, Deborah K.; Harms-Weissinger, Rebecca; Henry, Annie L.; Makarick, Lori J.; Ostoja, Steven M.; Reynolds, Lindsay V.; Robinson, W. Wright; Shafroth, Patrick B.; Tabacchi, Erich

    2017-01-01

    Control of invasive species within ecosystems may induce secondary invasions of non-target invaders replacing the first alien. We used four plant species listed as noxious by local authorities in riparian systems to discern whether 1) the severity of these secondary invasions was related to the control method applied to the first alien; and 2) which species that were secondary invaders persisted over time. In a collaborative study by 16 research institutions, we monitored plant species composition following control of non-native Tamarix trees along southwestern U.S. rivers using defoliation by an introduced biocontrol beetle, and three physical removal methods: mechanical using saws, heavy machinery, and burning in 244 treated and 79 untreated sites across six U.S. states. Physical removal favored secondary invasions immediately after Tamarix removal (0–3 yrs.), while in the biocontrol treatment, secondary invasions manifested later (> 5 yrs.). Within this general trend, the response of weeds to control was idiosyncratic; dependent on treatment type and invader. Two annual tumbleweeds that only reproduce by seed (Bassia scoparia and Salsola tragus) peaked immediately after physical Tamarix removal and persisted over time, even after herbicide application. Acroptilon repens, a perennial forb that vigorously reproduces by rhizomes, and Bromus tectorum, a very frequent annual grass before removal that only reproduces by seed, were most successful at biocontrol sites, and progressively spread as the canopy layer opened. These results demonstrate that strategies to control Tamarix affect secondary invasions differently among species and that time since disturbance is an important, generally overlooked, factor affecting response.

  11. Efficient distinction of invasive aquatic plant species from non-invasive related species using DNA barcoding.

    Science.gov (United States)

    Ghahramanzadeh, R; Esselink, G; Kodde, L P; Duistermaat, H; van Valkenburg, J L C H; Marashi, S H; Smulders, M J M; van de Wiel, C C M

    2013-01-01

    Biological invasions are regarded as threats to global biodiversity. Among invasive aliens, a number of plant species belonging to the genera Myriophyllum, Ludwigia and Cabomba, and to the Hydrocharitaceae family pose a particular ecological threat to water bodies. Therefore, one would try to prevent them from entering a country. However, many related species are commercially traded, and distinguishing invasive from non-invasive species based on morphology alone is often difficult for plants in a vegetative stage. In this regard, DNA barcoding could become a good alternative. In this study, 242 samples belonging to 26 species from 10 genera of aquatic plants were assessed using the chloroplast loci trnH-psbA, matK and rbcL. Despite testing a large number of primer sets and several PCR protocols, the matK locus could not be amplified or sequenced reliably and therefore was left out of the analysis. Using the other two loci, eight invasive species could be distinguished from their respective related species, a ninth one failed to produce sequences of sufficient quality. Based on the criteria of universal application, high sequence divergence and level of species discrimination, the trnH-psbA noncoding spacer was the best performing barcode in the aquatic plant species studied. Thus, DNA barcoding may be helpful with enforcing a ban on trade of such invasive species, such as is already in place in the Netherlands. This will become even more so once DNA barcoding would be turned into machinery routinely operable by a nonspecialist in botany and molecular genetics. © 2012 Blackwell Publishing Ltd.

  12. Seed bank survival of an invasive species, but not of two native species, declines with invasion.

    Science.gov (United States)

    Orrock, John L; Christopher, Cory C; Dutra, Humberto P

    2012-04-01

    Soil-borne seed pathogens may play an important role in either hindering or facilitating the spread of invasive exotic plants. We examined whether the invasive shrub Lonicera maackii (Caprifoliaceae) affected fungi-mediated mortality of conspecific and native shrub seeds in a deciduous forest in eastern Missouri. Using a combination of L. maackii removal and fungicide treatments, we found no effect of L. maackii invasion on seed viability of the native Symphoricarpos orbiculatus (Caprifoliaceae) or Cornus drummondii (Cornaceae). In contrast, fungi were significant agents of L. maackii seed mortality in invaded habitats. Losses of L. maackii to soil fungi were also significant in invaded habitats where L. maackii had been removed, although the magnitude of the effect of fungi was lower, suggesting that changes in soil chemistry or microhabitat caused by L. maackii were responsible for affecting fungal seed pathogens. Our work suggests that apparent competition via soil pathogens is not an important factor contributing to impacts of L. maackii on native shrubs. Rather, we found that fungal seed pathogens have density-dependent effects on L. maackii seed survival. Therefore, while fungal pathogens may provide little biotic resistance to early invasion by L. maackii, our study illustrates that more work is needed to understand how changes in fungal pathogens during the course of an invasion contribute to the potential for restoration of invaded systems. More generally, our study suggests that increased rates of fungal pathogen attack may be realized by invasive plants, such as L. maackii, that change the chemical or physical environment of the habitats they invade.

  13. Granivory of invasive, naturalized, and native plants in communities differentially susceptible to invasion.

    Science.gov (United States)

    Connolly, B M; Pearson, D E; Mack, R N

    2014-07-01

    Seed predation is an important biotic filter that can influence abundance and spatial distributions of native species through differential effects on recruitment. This filter may also influence the relative abundance of nonnative plants within habitats and the communities' susceptibility to invasion via differences in granivore identity, abundance, and food preference. We evaluated the effect of postdispersal seed predators on the establishment of invasive, naturalized, and native species within and between adjacent forest and steppe communities of eastern Washington, USA that differ in severity of plant invasion. Seed removal from trays placed within guild-specific exclosures revealed that small mammals were the dominant seed predators in both forest and steppe. Seeds of invasive species (Bromus tectorum, Cirsium arvense) were removed significantly less than the seeds of native (Pseudoroegneria spicata, Balsamorhiza sagittata) and naturalized (Secale cereale, Centaurea cyanus) species. Seed predation limited seedling emergence and establishment in both communities in the absence of competition in a pattern reflecting natural plant abundance: S. cereale was most suppressed, B. tectorum was least suppressed, and P. spicata was suppressed at an intermediate level. Furthermore, seed predation reduced the residual seed bank for all species. Seed mass correlated with seed removal rates in the forest and their subsequent effects on plant recruitment; larger seeds were removed at higher rates than smaller seeds. Our vegetation surveys indicate higher densities and canopy cover of nonnative species occur in the steppe compared with the forest understory, suggesting the steppe may be more susceptible to invasion. Seed predation alone, however, did not result in significant differences in establishment for any species between these communities, presumably due to similar total small-mammal abundance between communities. Consequently, preferential seed predation by small

  14. Responses of the soil fungal communities to the co-invasion of two invasive species with different cover classes.

    Science.gov (United States)

    Wang, C; Zhou, J; Liu, J; Jiang, K; Xiao, H; Du, D

    2018-01-01

    Soil fungal communities play an important role in the successful invasion of non-native species. It is common for two or more invasive plant species to co-occur in invaded ecosystems. This study aimed to determine the effects of co-invasion of two invasive species (Erigeron annuus and Solidago canadensis) with different cover classes on soil fungal communities using high-throughput sequencing. Invasion of E. annuus and/or S. canadensis had positive effects on the sequence number, operational taxonomic unit (OTU) richness, Shannon diversity, abundance-based cover estimator (ACE index) and Chao1 index of soil fungal communities, but negative effects on the Simpson index. Thus, invasion of E. annuus and/or S. canadensis could increase diversity and richness of soil fungal communities but decrease dominance of some members of these communities, in part to facilitate plant further invasion, because high soil microbial diversity could increase soil functions and plant nutrient acquisition. Some soil fungal species grow well, whereas others tend to extinction after non-native plant invasion with increasing invasion degree and presumably time. The sequence number, OTU richness, Shannon diversity, ACE index and Chao1 index of soil fungal communities were higher under co-invasion of E. annuus and S. canadensis than under independent invasion of either individual species. The co-invasion of the two invasive species had a positive synergistic effect on diversity and abundance of soil fungal communities, partly to build a soil microenvironment to enhance competitiveness of the invaders. The changed diversity and community under co-invasion could modify resource availability and niche differentiation within the soil fungal communities, mediated by differences in leaf litter quality and quantity, which can support different fungal/microbial species in the soil. © 2017 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

  15. Introduced and invasive cactus species: a global review

    Science.gov (United States)

    Novoa, Ana; Le Roux, Johannes J.; Robertson, Mark P.; Wilson, John R.U.; Richardson, David M.

    2015-01-01

    Understanding which species are introduced and become invasive, and why, are central questions in invasion science. Comparative studies on model taxa have provided important insights, but much more needs to be done to unravel the context dependencies of these findings. The cactus family (Cactaceae), one of the most popular horticultural plant groups, is an interesting case study. Hundreds of cactus species have been introduced outside their native ranges; a few of them are among the most damaging invasive plant species in the world. We reviewed the drivers of introductions and invasions in the family and seek insights that can be used to minimize future risks. We compiled a list of species in the family and determined which have been recorded as invasive. We also mapped current global distributions and modelled the potential global distributions based on distribution data of known invasive taxa. Finally, we identified whether invasiveness is phylogenetically clustered for cacti and whether particular traits are correlated with invasiveness. Only 57 of the 1922 cactus species recognized in this treatment have been recorded as invasive. There are three invasion hotspots: South Africa (35 invasive species recorded), Australia (26 species) and Spain (24 species). However, there are large areas of the world with climates suitable for cacti that are at risk of future invasion—in particular, parts of China, eastern Asia and central Africa. The invasive taxa represent an interesting subset of the total species pool. There is a significant phylogenetic signal: invasive species occur in 2 of the 3 major phylogenetic clades and in 13 of the 130 genera. This phylogenetic signal is not driven by human preference, i.e. horticultural trade, but all invasive species are from 5 of the 12 cactus growth forms. Finally, invasive species tend to have significantly larger native ranges than non-invasive species, and none of the invasive species are of conservation concern in their

  16. The stock of invasive insect species and its economic determinants.

    Science.gov (United States)

    Hlasny, Vladimir

    2011-06-01

    Invasions of nonindigenous organisms have long been linked to trade, but the contribution of individual trade pathways remains poorly understood, because species are not observed immediately upon arrival and the number of species arriving annually is unknown. Species interception records may count both new arrivals and species long introduced. Furthermore, the stock of invasive insect species already present is unknown. In this study, a state-space model is used to infer the stock of detected as well as undetected invasive insect species established in the United States. A system of equations is estimated jointly to distinguish the patterns of introduction, identification, and eradication. Introductions of invasive species are modeled as dependent on the volume of trade and arrival of people. Identifications depend on the public efforts at invasive species research, as well as on the established stock of invasive species that remain undetected. Eradications of both detected and undetected invasive species depend on containment and quarantine efforts, as well as on the stock of all established invasive species. These patterns are estimated by fitting the predicted number of invasive species detections to the observed record in the North American Non-Indigenous Arthropod Database. The results indicate that agricultural imports are the most important pathway of introduction, followed by immigration of people. Expenditures by the U.S. Department of Agriculture and the Agricultural Research Service are found to explain the species identification record well. Between three and 38 invasive insect species are estimated to be established in the United States undetected.

  17. News from the western European invasion front

    Directory of Open Access Journals (Sweden)

    Filipe Ribeiro

    2015-11-01

    Full Text Available Invasive species are one of the main threats to aquatic biodiversity, being particularly serious in regions with high number of endemic and endangered fishes. Portugal has currently one of the highest numbers of non-native fishes per area in western Europe and the rate of species arrival is increasing. In this review, an updated status of non-native fishes is provided with recent trends of leading vectors and routes. Non-native fish component represents 31% of the freshwater fish diversity existing in the country, totaling 20 established species out of 28 introduced species. In the last decade, the non-native fish detection rate (a proxy of introduction rate has been one new species in every two years. Most of the non-native fishes in Portugal are mainly from Central Europe and North America and were illegally introduced for sports fisheries. However, some recent records are also linked with the ornamental trade, from Asia, indicating an increase of this vector in fish introductions. The international drainages exhibit the highest number of non-native fishes due to prevalent invasion routes from Spain, although direct introductions to national drainages in spatially limited areas suggest new invasion routes caused by higher propagule pressure of leading vectors (fisheries and ornamental trade. Management options are presented in order to tackle this growing threat, namely risk assessment, enforcement and environmental education. Only a comprehensive and integrated approach at an Iberian level could reduce the current rate of non-native species arrival to this region and help us to preserve the Iberian freshwater fishes for future generations.

  18. News from the western European invasion front

    OpenAIRE

    Filipe Ribeiro

    2015-01-01

    Invasive species are one of the main threats to aquatic biodiversity, being particularly serious in regions with high number of endemic and endangered fishes. Portugal has currently one of the highest numbers of non-native fishes per area in western Europe and the rate of species arrival is increasing. In this review, an updated status of non-native fishes is provided with recent trends of leading vectors and routes. Non-native fish component represents 31% of the freshwater fish diversity ex...

  19. Minimally invasive surgery for esophageal achalasia.

    Science.gov (United States)

    Chen, Huan-Wen; Du, Ming

    2016-07-01

    Esophageal achalasia is due to the esophagus of neuromuscular dysfunction caused by esophageal functional disease. Its main feature is the lack of esophageal peristalsis, the lower esophageal sphincter pressure and to reduce the swallow's relaxation response. Lower esophageal muscular dissection is one of the main ways to treat esophageal achalasia. At present, the period of muscular layer under the thoracoscope esophagus dissection is one of the treatment of esophageal achalasia. Combined with our experience in minimally invasive esophageal surgery, to improved incision and operation procedure, and adopts the model of the complete period of muscular layer under the thoracoscope esophagus dissection in the treatment of esophageal achalasia.

  20. Invasive Crabs in the Barents Sea

    DEFF Research Database (Denmark)

    Kaiser, Brooks; Fernandez, Linda; Kourantidou, Melina

    The recent invasions of the red king crab (RKC) and the snow crab (SC) in the Barents Sea represent the sorts of integrated ecological and economic shifts we may expect as climate change affects arctic seas. Economic incentives and ecological unknowns have combined to change the current...... and potentially future productivity and profitability of the Barents ecosystem in complex and interacting ways. We examine potential ecological-economic trajectories for these crabs’ continued expansions in the Arctic and how the profitability, the joint and national management structures in Norway and Russia...