WorldWideScience

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. Nestedness in mutualistic networks

    OpenAIRE

    Rohr, Rudolf P.; Fortuna, Miguel A.; Luque, Bartolo; Bascompte, Jordi

    2013-01-01

    James et al. (2012) presented simulations that apparently falsify the analytical result by Bastolla et al. (2009), who showed that nested mutualistic interactions decrease interspecific competition and increase biodiversity in model ecosystems. This contradiction, however, mainly stems from the incorrect application of formulas derived for fully connected networks to empirical, sparse networks.

  4. Will the introduction of non-invasive prenatal diagnostic testing erode informed choices? An experimental study of health care professionals.

    Science.gov (United States)

    van den Heuvel, Ananda; Chitty, Lyn; Dormandy, Elizabeth; Newson, Ainsley; Deans, Zuzana; Attwood, Sophie; Haynes, Shelley; Marteau, Theresa M

    2010-01-01

    Informed choice is a fundamental concept within prenatal care. The present study assessed the extent to which the introduction of non-invasive prenatal diagnosis (NIPD) of Down's syndrome may undermine the process of making informed choices to undergo prenatal testing or screening for Down's syndrome by altering the quality and quantity of pre-test counselling. 231 obstetricians and midwives were randomly allocated one of three vignettes, each describing a different type of test: (a) invasive prenatal diagnosis (IPD), (b) non-invasive prenatal diagnosis (NIPD) or (c) Down's syndrome screening (DSS). Participants were then asked to complete a questionnaire assessing (1) the information considered important to communicate to women, (2) whether test offer and uptake should take place on different days, and (3) whether signed consent forms should be obtained prior to testing. Across the three test types, five out of the seven presented topics were considered equally important to communicate, including the information that testing is the woman's choice. Compared with participants receiving the IPD vignette, those receiving the NIPD and DSS vignettes were less likely to report that counselling and testing should occur on different days (IPD 94.7% versus 74.1% and 73.9% for NIPD and DSS respectively, p=.001) and that written consent was a necessity (IPD 96.1% versus 68.3% and 75.4% for NIPD and DSS respectively, pprenatal diagnostic testing for conditions like DS. Given the importance of informed choice in reproductive decision-making, implementation of any programme based on NIPD should be designed to facilitate this.

  5. 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.

  6. 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...

  7. Phenology drives mutualistic network structure and diversity

    NARCIS (Netherlands)

    Encinas Viso, Francisco; Revilla, Tomas A; Etienne, Rampal S.

    Several network properties have been identified as determinants of the stability and complexity of mutualistic networks. However, it is unclear which mechanisms give rise to these network properties. Phenology seems important, because it shapes the topology of mutualistic networks, but its effects

  8. Hot spots of mutualistic networks.

    Science.gov (United States)

    Gilarranz, Luis J; Sabatino, Malena; Aizen, Marcelo A; Bascompte, Jordi

    2015-03-01

    Incorporating interactions into a biogeographical framework may serve to understand how interactions and the services they provide are distributed in space. We begin by simulating the spatiotemporal dynamics of realistic mutualistic networks inhabiting spatial networks of habitat patches. We proceed by comparing the predicted patterns with the empirical results of a set of pollination networks in isolated hills of the Argentinian Pampas. We first find that one needs to sample up to five times as much area to record interactions as would be needed to sample the same proportion of species. Secondly, we find that peripheral patches have fewer interactions and harbour less nested networks - therefore potentially less resilient communities - compared to central patches. Our results highlight the important role played by the structure of dispersal routes on the spatial distribution of community patterns. This may help to understand the formation of biodiversity hot spots. © 2014 The Authors. Journal of Animal Ecology © 2014 British Ecological Society.

  9. Filled/Eroded Craters

    Science.gov (United States)

    2005-01-01

    14 October 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows rugged terrain in northern Arabia Terra. The circular features are the remains of old meteor impact craters -- either the eroded remnants of the interiors of craters, or the remains of craters that were filled by layered material. The martian bedrock has craters of all sizes and states of erosion interbedded with its layered materials. Location near: 31.4oN, 299.0oW Image width: width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Winter

  10. 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.

  11. Restricting mutualistic partners to enforce trade reliance

    NARCIS (Netherlands)

    Wyatt, G.A.K.; Kiers, E.T.; Gardner, A.

    2016-01-01

    Mutualisms are cooperative interactions between members of different species, often involving the trade of resources. Here, we suggest that otherwise-cooperative mutualists might be able to gain a benefit from actively restricting their partners' ability to obtain resources directly, hampering the

  12. 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 forage on crude substrates such as insect frass and dry plant material, to large colonies of the leaf-cutting ants with several thousands to several million workers that provide live plant material to their fungus gardens. Leaf-cutting ants are the dominant herbivores of the Neo-tropics, and have a major...... contribution to cycling of nitrogen and phosphorus in their direct environment and are, furthermore, considered pest species as they have a large impact on human agriculture. These factors make leaf-cutting ants an ideal study subject to better understand the mechanisms that make this mutualistic symbiosis so...

  13. Emerging directions in the study of the ecology and evolution of plant-animal mutualistic networks: a review.

    Science.gov (United States)

    Gu, Hao; Goodale, Eben; Chen, Jin

    2015-03-18

    The study of mutualistic plant and animal networks is an emerging field of ecological research. We reviewed progress in this field over the past 30 years. While earlier studies mostly focused on network structure, stability, and biodiversity maintenance, recent studies have investigated the conservation implications of mutualistic networks, specifically the influence of invasive species and how networks respond to habitat loss. Current research has also focused on evolutionary questions including phylogenetic signal in networks, impact of networks on the coevolution of interacting partners, and network influences on the evolution of interacting species. We outline some directions for future research, particularly the evolution of specialization in mutualistic networks, and provide concrete recommendations for environmental managers.

  14. Indirect effects drive coevolution in mutualistic networks.

    Science.gov (United States)

    Guimarães, Paulo R; Pires, Mathias M; Jordano, Pedro; Bascompte, Jordi; Thompson, John N

    2017-10-26

    Ecological interactions have been acknowledged to play a key role in shaping biodiversity. Yet a major challenge for evolutionary biology is to understand the role of ecological interactions in shaping trait evolution when progressing from pairs of interacting species to multispecies interaction networks. Here we introduce an approach that integrates coevolutionary dynamics and network structure. Our results show that non-interacting species can be as important as directly interacting species in shaping coevolution within mutualistic assemblages. The contribution of indirect effects differs among types of mutualism. Indirect effects are more likely to predominate in nested, species-rich networks formed by multiple-partner mutualisms, such as pollination or seed dispersal by animals, than in small and modular networks formed by intimate mutualisms, such as those between host plants and their protective ants. Coevolutionary pathways of indirect effects favour ongoing trait evolution by promoting slow but continuous reorganization of the adaptive landscape of mutualistic partners under changing environments. Our results show that coevolution can be a major process shaping species traits throughout ecological networks. These findings expand our understanding of how evolution driven by interactions occurs through the interplay of selection pressures moving along multiple direct and indirect pathways.

  15. 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…

  16. Metabolic modeling of a mutualistic microbial community

    Energy Technology Data Exchange (ETDEWEB)

    Stolyar, Sergey; Van Dien, Steve; Hillesland, Kristina Linnea; Pinel, Nicolas; Lie, Thomas J.; Leigh, John A.; Stahl, David A.

    2007-03-13

    The rate of production of methane in many environmentsdepends upon mutualistic interactions between sulfate-reducing bacteriaand methanogens. To enhance our understanding of these relationships, wetook advantage of the fully sequenced genomes of Desulfovibrio vulgarisand Methanococcus maripaludis to produce and analyze the firstmultispecies stoichiometric metabolic model. Model results were comparedto data on growth of the co-culture on lactate in the absence of sulfate.The model accurately predicted several ecologically relevantcharacteristics, including the flux of metabolites and the ratio of D.vulgaris to M. maripaludis cells during growth. In addition, the modeland our data suggested that it was possible to eliminate formate as aninterspecies electron shuttle, but hydrogen transfer was essential forsyntrophic growth. Our work demonstrated that reconstructed metabolicnetworks and stoichiometric models can serve not only to predictmetabolic fluxes and growth phenotypes of single organisms, but also tocapture growth parameters and community composition of simple bacterialcommunities.

  17. 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

  18. 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.

  19. Emergence of structural and dynamical properties of ecological mutualistic networks.

    Science.gov (United States)

    Suweis, Samir; Simini, Filippo; Banavar, Jayanth R; Maritan, Amos

    2013-08-22

    Mutualistic networks are formed when the interactions between two classes of species are mutually beneficial. They are important examples of cooperation shaped by evolution. Mutualism between animals and plants has a key role in the organization of ecological communities. Such networks in ecology have generally evolved a nested architecture independent of species composition and latitude; specialist species, with only few mutualistic links, tend to interact with a proper subset of the many mutualistic partners of any of the generalist species. Despite sustained efforts to explain observed network structure on the basis of community-level stability or persistence, such correlative studies have reached minimal consensus. Here we show that nested interaction networks could emerge as a consequence of an optimization principle aimed at maximizing the species abundance in mutualistic communities. Using analytical and numerical approaches, we show that because of the mutualistic interactions, an increase in abundance of a given species results in a corresponding increase in the total number of individuals in the community, and also an increase in the nestedness of the interaction matrix. Indeed, the species abundances and the nestedness of the interaction matrix are correlated by a factor that depends on the strength of the mutualistic interactions. Nestedness and the observed spontaneous emergence of generalist and specialist species occur for several dynamical implementations of the variational principle under stationary conditions. Optimized networks, although remaining stable, tend to be less resilient than their counterparts with randomly assigned interactions. In particular, we show analytically that the abundance of the rarest species is linked directly to the resilience of the community. Our work provides a unifying framework for studying the emergent structural and dynamical properties of ecological mutualistic networks.

  20. 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.

  1. 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.

  2. 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.

  3. Changes in population dynamics in mutualistic versus pathogenic viruses.

    Science.gov (United States)

    Roossinck, Marilyn J

    2011-01-01

    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.

  4. Plants transfer lipids to sustain colonization by mutualistic mycorrhizal and parasitic fungi.

    Science.gov (United States)

    Jiang, Yina; Wang, Wanxiao; Xie, Qiujin; Liu, Na; Liu, Lixia; Wang, Dapeng; Zhang, Xiaowei; Yang, Chen; Chen, Xiaoya; Tang, Dingzhong; Wang, Ertao

    2017-06-16

    Arbuscular mycorrhizal (AM) fungi facilitate plant uptake of mineral nutrients and draw organic nutrients from the plant. Organic nutrients are thought to be supplied primarily in the form of sugars. Here we show that the AM fungus Rhizophagus irregularis is a fatty acid auxotroph and that fatty acids synthesized in the host plants are transferred to the fungus to sustain mycorrhizal colonization. The transfer is dependent on RAM2 (REQUIRED FOR ARBUSCULAR MYCORRHIZATION 2) and the ATP binding cassette transporter-mediated plant lipid export pathway. We further show that plant fatty acids can be transferred to the pathogenic fungus Golovinomyces cichoracerum and are required for colonization by pathogens. We suggest that the mutualistic mycorrhizal and pathogenic fungi similarly recruit the fatty acid biosynthesis program to facilitate host invasion. Copyright © 2017, American Association for the Advancement of Science.

  5. 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.

  6. 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...

  7. Mouvement mutualiste au Togo : Une opportunite Pour la prise en ...

    African Journals Online (AJOL)

    En dépit du soutien financier des institutions partenaires tant étatiques que non gouvernementales, les Associations ne sont arrivées jamais à satisfaire les ... Mais la stratégie qui pourra faciliter cette implication des PVVIH consiste à transformer le fonctionnement des Associations en système mutualiste caractérisé par la ...

  8. 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.

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

    Science.gov (United States)

    Amor, Daniel R; Montañez, Raúl; Duran-Nebreda, Salva; Solé, Ricard

    2017-08-01

    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.

  10. Mutualistic rhizobia reduce plant diversity and alter community composition.

    Science.gov (United States)

    Keller, Kane R

    2014-12-01

    Mutualistic interactions can be just as important to community dynamics as antagonistic species interactions like competition and predation. Because of their large effects on both abiotic and biotic environmental variables, resource mutualisms, in particular, have the potential to influence plant communities. Moreover, the effects of resource mutualists such as nitrogen-fixing rhizobia on diversity and community composition may be more pronounced in nutrient-limited environments. I experimentally manipulated the presence of rhizobia across a nitrogen gradient in early assembling mesocosm communities with identical starting species composition to test how the classic mutualism between nitrogen-fixing rhizobia and their legume host influence diversity and community composition. After harvest, I assessed changes in α-diversity, community composition, β-diversity, and ecosystem properties such as inorganic nitrogen availability and productivity as a result of rhizobia and nitrogen availability. The presence of rhizobia decreased plant community diversity, increased community convergence (reduced β-diversity), altered plant community composition, and increased total community productivity. These community-level effects resulted from rhizobia increasing the competitive dominance of their legume host Chamaecrista fasciculata. Moreover, different non-leguminous species responded both negatively and positively to the presence of rhizobia, indicating that rhizobia are driving both inhibitory and potentially facilitative effects in communities. These findings expand our understanding of plant communities by incorporating the effects of positive symbiotic interactions on plant diversity and composition. In particular, rhizobia that specialize on dominant plants may serve as keystone mutualists in terrestrial plant communities, reducing diversity by more than 40%.

  11. 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.

  12. Coexistence through mutualist-dependent reversal of competitive hierarchies.

    Science.gov (United States)

    Mehrparvar, Mohsen; Zytynska, Sharon E; Balog, Adalbert; Weisser, Wolfgang W

    2018-01-01

    Mechanisms that allow for the coexistence of two competing species that share a trophic level can be broadly divided into those that prevent competitive exclusion of one species within a local area, and those that allow for coexistence only at a regional level. While the presence of aphid-tending ants can change the distribution of aphids among host plants, the role of mutualistic ants has not been fully explored to understand coexistence of multiple aphid species in a community. The tansy plant ( Tanacetum vulgare ) hosts three common and specialized aphid species, with only one being tended by ants. Often, these aphids species will not coexist on the same plant but will coexist across multiple plant hosts in a field. In this study, we aim to understand how interactions with mutualistic ants and predators affect the coexistence of multiple species of aphid herbivores on tansy. We show that the presence of ants drives community assembly at the level of individual plant, that is, the local community, by favoring one ant-tended species, Metopeurum fuscoviride , while preying on the untended Macrosiphoniella tanacetaria and, to a lesser extent, Uroleucon tanaceti . Competitive hierarchies without ants were very different from those with ants. At the regional level, multiple tansy plants provide a habitat across which all aphid species can coexist at the larger spatial scale, while being competitively excluded at the local scale. In this case, ant mutualist-dependent reversal of the competitive hierarchy can drive community dynamics in a plant-aphid system.

  13. The Changing Mood in America. Eroding Commitment?

    Science.gov (United States)

    Jones, Faustine Childress; And Others

    This book examines the current social climate in the United States to determine whether there is an eroding social commitment to equal opportunity for blacks and other minorities and the poor. It is concluded that there is a changing mood in the dominant society, in the black population, and in all three branches of the federal government, and it…

  14. 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...

  15. Sustainable agriculture: possible trajectories from mutualistic symbiosis and plant neodomestication.

    Science.gov (United States)

    Duhamel, Marie; Vandenkoornhuyse, Philippe

    2013-11-01

    Food demand will increase concomitantly with human population. Food production therefore needs to be high enough and, at the same time, minimize damage to the environment. This equation cannot be solved with current strategies. Based on recent findings, new trajectories for agriculture and plant breeding which take into account the belowground compartment and evolution of mutualistic strategy, are proposed in this opinion article. In this context, we argue that plant breeders have the opportunity to make use of native arbuscular mycorrhizal (AM) symbiosis in an innovative ecologically intensive agriculture. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. 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.

  17. Estimation of riverbank soil erodibility parameters using genetic ...

    Indian Academy of Sciences (India)

    Tapas Karmaker

    2017-11-07

    Nov 7, 2017 ... sion primarily depends on soil erodibility parameters and the developed shear stress. The erodibility parameters include the critical shear stress and the erodibility coeffi- cient. Critical shear stress can be defined as the limiting shear stress developed due to flowing water, if in excess, will lead to soil erosion ...

  18. Mutualistic ants contribute to tank-bromeliad nutrition

    Science.gov (United States)

    Leroy, Céline; Carrias, Jean-François; Corbara, Bruno; Pélozuelo, Laurent; Dézerald, Olivier; Brouard, Olivier; Dejean, Alain; Céréghino, Régis

    2013-01-01

    Background and Aims Epiphytism imposes physiological constraints resulting from the lack of access to the nutrient sources available to ground-rooted plants. A conspicuous adaptation in response to that lack is the phytotelm (plant-held waters) of tank-bromeliad species that are often nutrient-rich. Associations with terrestrial invertebrates also result in higher plant nutrient acquisition. Assuming that tank-bromeliads rely on reservoir-assisted nutrition, it was hypothesized that the dual association with mutualistic ants and the phytotelm food web provides greater nutritional benefits to the plant compared with those bromeliads involved in only one of these two associations. Methods Quantitative (water volume, amount of fine particulate organic matter, predator/prey ratio, algal density) and qualitative variables (ant-association and photosynthetic pathways) were compared for eight tank- and one tankless-bromeliad morphospecies from French Guiana. An analysis was also made of which of these variables affect nitrogen acquisition (leaf N and δ15N). Key Results All variables were significantly different between tank-bromeliad species. Leaf N concentrations and leaf δ15N were both positively correlated with the presence of mutualistic ants. The amount of fine particulate organic matter and predator/prey ratio had a positive and negative effect on leaf δ15N, respectively. Water volume was positively correlated with leaf N concentration whereas algal density was negatively correlated. Finally, the photosynthetic pathway (C3 vs. CAM) was positively correlated with leaf N concentration with a slightly higher N concentration for C3-Tillandsioideae compared with CAM-Bromelioideae. Conclusions The study suggests that some of the differences in N nutrition between bromeliad species can be explained by the presence of mutualistic ants. From a nutritional standpoint, it is more advantageous for a bromeliad to use myrmecotrophy via its roots than to use carnivory via its

  19. Ecological networks. On the structural stability of mutualistic systems.

    Science.gov (United States)

    Rohr, Rudolf P; Saavedra, Serguei; Bascompte, Jordi

    2014-07-25

    In theoretical ecology, traditional studies based on dynamical stability and numerical simulations have not found a unified answer to the effect of network architecture on community persistence. Here, we introduce a mathematical framework based on the concept of structural stability to explain such a disparity of results. We investigated the range of conditions necessary for the stable coexistence of all species in mutualistic systems. We show that the apparently contradictory conclusions reached by previous studies arise as a consequence of overseeing either the necessary conditions for persistence or its dependence on model parameterization. We show that observed network architectures maximize the range of conditions for species coexistence. We discuss the applicability of structural stability to study other types of interspecific interactions. Copyright © 2014, American Association for the Advancement of Science.

  20. Specialization of mutualistic interaction networks decreases toward tropical latitudes

    DEFF Research Database (Denmark)

    Schleuning, Matthias; Fründ, Jochen; Klein, Alexandra-Maria

    2012-01-01

    to low plant diversity. This could explain why the latitudinal specialization gradient is reversed relative to the latitudinal diversity gradient. Low mutualistic network specialization in the tropics suggests higher tolerance against extinctions in tropical than in temperate communities.......Species-rich tropical communities are expected to be more specialized than their temperate counterparts [1-3]. Several studies have reported increasing biotic specialization toward the tropics [4-7], whereas others have not found latitudinal trends once accounting for sampling bias [8, 9......] 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...

  1. 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

    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 o...

  2. Abiotic conditions affect floral antagonists and mutualists of Impatiens capensis (Balsaminaceae).

    Science.gov (United States)

    Soper Gorden, Nicole L; Adler, Lynn S

    2013-04-01

    While the effect of abiotic factors on leaf herbivory is well known, the relative importance of abiotic conditions influencing both mutualists and antagonists is less well understood. Species interactions could enhance or reduce the direct effects of abiotic factors, depending on how mutualists and antagonists respond to abiotic conditions. We manipulated soil nutrients and shade in a factorial design and measured soil moisture in the annual Impatiens capensis. We then measured interactions with mutualists (two pollinating species) and antagonists (herbivores, florivores, nectar thieves, and flower bud gallers), as well as plant growth, floral rewards, and plant reproduction. Fertilizer increased plant growth, floral attractiveness, mutualist and antagonist interactions, and plant reproduction. Shade had no effects, and soil moisture was negatively associated with plant growth and reproduction. All effects were additive. Mutualist and antagonist floral interactions both increased on fertilized plants, but antagonists increased at a greater rate, leading to a larger ratio of antagonist to mutualist interactions on fertilized plants. Despite having more antagonists, fertilized plants still had significantly higher reproduction, suggesting higher tolerance to antagonists. Abiotic effects can have consistent effects on antagonists and mutualists, and on both floral and leaf antagonists. However, tolerance to antagonisms increased in favorable conditions. Thus, the direct positive effects of favorable abiotic conditions on plants outweighed negative indirect effects via increased antagonisms, which may lead to selection to grow in high-nutrient microsites in spite of increased herbivory.

  3. Disclosing the double mutualist role of birds on Galápagos

    DEFF Research Database (Denmark)

    Olesen, Jens M; Damgaard, Christian F; Fuster, Francisco

    2018-01-01

    of the network, because they are traditionally considered rare. We sampled pollination and seed-dispersal interactions on Galápagos and constructed a plant-bird mutualism network of 108 plant (12% being double mutualists) and 21 bird species (48% being double mutualists), and their 479 interactions, being either...... single (95%) or double mutualisms (5%). Double mutualists constitute the core in the pollination-dispersal network, coupling the two link types together. They may also initiate positive feedbacks (more pollination leading to more dispersal), which theoretically are known to be unstable. Thus, double...

  4. 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.

  5. 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.

  6. Nature of the interactions between hypocrealean fungi and the mutualistic fungus of leaf-cutter ants.

    Science.gov (United States)

    Varanda-Haifig, Sadala Schmidt; Albarici, Tatiane Regina; Nunes, Pablo Henrique; Haifig, Ives; Vieira, Paulo Cezar; Rodrigues, Andre

    2017-04-01

    Leaf-cutter ants cultivate and feed on the mutualistic fungus, Leucoagaricus gongylophorus, which is threatened by parasitic fungi of the genus Escovopsis. The mechanism of Escovopsis parasitism is poorly understood. Here, we assessed the nature of the antagonism of different Escovopsis species against its host. We also evaluated the potential antagonism of Escovopsioides, a recently described fungal genus from the attine ant environment whose role in the colonies of these insects is unknown. We performed dual-culture assays to assess the interactions between L. gongylophorus and both fungi. We also evaluated the antifungal activity of compounds secreted by the latter on L. gongylophorus growth using crude extracts of Escovopsis spp. and Escovopsioides nivea obtained either in (1) absence or (2) presence of the mutualistic fungus. The physical interaction between these fungi and the mutualistic fungus was examined under scanning electron microscopy (SEM). Escovopsis spp. and E. nivea negatively affected the growth of L. gongylophorus, which was also significantly inhibited by both types of crude extract. These results indicate that Escovopsis spp. and E. nivea produce antifungal metabolites against the mutualistic fungus. SEM showed that Escovopsis spp. and E. nivea maintained physical contact with the mutualistic fungus, though no specialised structures related to mycoparasitism were observed. These results showed that Escovopsis is a destructive mycoparasite that needs physical contact for the death of the mutualistic fungus to occur. Also, our findings suggest that E. nivea is an antagonist of the ant fungal cultivar.

  7. 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.

  8. 76 FR 82075 - Highly Erodible Land and Wetland Conservation

    Science.gov (United States)

    2011-12-30

    ... Secretary 7 CFR Part 12 RIN 0560-AH97 Highly Erodible Land and Wetland Conservation AGENCY: Office of the... ``good faith'' provisions in the USDA regulations allow violators of highly erodible land conservation (HELC) or wetland conservation (WC) provisions to retain eligibility for USDA program benefits if...

  9. THE INFLUENCE OF SOME SOIL CHEMICAL PROPERTIES ON THEIR ERODABILITY

    Directory of Open Access Journals (Sweden)

    I. C. Stanga

    2005-10-01

    Full Text Available Soils from de hills and tableland regions, as well as those from subcarpathian area are characterized through higher erodability. The soils from mountain area present the lowest erodability, especially districambosol, due to the upper horizons properties. The erodabilidydepends on the ratio of historical geological erosion and surface erosion.

  10. Estimation of riverbank soil erodibility parameters using genetic ...

    Indian Academy of Sciences (India)

    Tapas Karmaker

    2017-11-07

    Nov 7, 2017 ... Abstract. Determination of the erodibility parameters, such as critical shear stress and erodibility coefficient, are necessary before estimating the annual bank erosion (or bank retreat) at river reaches. However, in many cases, the river site is inaccessible making it difficult to assess the soil parameters either ...

  11. Bats Are Acoustically Attracted to Mutualistic Carnivorous Plants.

    Science.gov (United States)

    Schöner, Michael G; Schöner, Caroline R; Simon, Ralph; Grafe, T Ulmar; Puechmaille, Sébastien J; Ji, Liaw Lin; Kerth, Gerald

    2015-07-20

    Mutualisms between plants and animals shape the world's ecosystems. In such interactions, achieving contact with the partner species is imperative. Plants regularly advertise themselves with signals that specifically appeal to the partner's perceptual preferences. For example, many plants have acquired traits such as brightly colored, fragrant flowers that attract pollinators with visual, olfactory, or--in the case of a few bat-pollinated flowers--even acoustic stimuli in the form of echo-reflecting structures. However, acoustic attraction in plants is rare compared to other advertisements and has never been found outside the pollination context and only in the Neotropics. We hypothesized that this phenomenon is more widespread and more diverse as plant-bat interactions also occur in the Paleotropics. In Borneo, mutualistic bats fertilize a carnivorous pitcher plant while roosting in its pitchers. The pitcher's orifice features a prolonged concave structure, which we predicted to distinctively reflect the bats' echolocation calls for a wide range of angles. This structure should facilitate the location and identification of pitchers even within highly cluttered surroundings. Pitchers lacking this structure should be less attractive for the bats. Ensonifications of the pitchers around their orifice revealed that this structure indeed acts as a multidirectional ultrasound reflector. In behavioral experiments where bats were confronted with differently modified pitchers, the reflector's presence clearly facilitated the finding and identification of pitchers. These results suggest that plants have convergently acquired reflectors in the Paleotropics and the Neotropics to acoustically attract bats, albeit for completely different ecological reasons. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Social transmission of information about a mutualist via trophallaxis in ant colonies.

    Science.gov (United States)

    Hayashi, Masayuki; Hojo, Masaru K; Nomura, Masashi; Tsuji, Kazuki

    2017-08-30

    Partner discrimination is crucial in mutualistic interactions between organisms to counteract cheating by the partner. Trophobiosis between ants and aphids is a model system of such mutualistic interaction. To establish and maintain the mutualistic association, ants need to correctly discriminate mutualistic aphids. However, the mechanism by which ants recognize aphids as their partners is poorly understood, despite its ecological and evolutionary importance. Here, we show for the first time the evidence that interaction with nest-mates that have tended aphids ( Aphis craccivora ) allows ants ( Tetramorium tsushimae ) to learn to recognize the aphid species as their partner. When ants had previously tended aphids, they moderated their aggressiveness towards aphids. More importantly, ants that had interacted with aphid-experienced nest-mates also reduced their aggressiveness towards aphids, even though they had never directly experienced them, indicating that aphid information was transmitted from aphid-experienced ants to inexperienced ants. Furthermore, inhibition of mouth-to-mouth contact (trophallaxis) from aphid-experienced ants to inexperienced ants by providing the inexperienced ants with artificial honeydew solution caused the inexperienced ants to become aggressive towards aphids. These results, with further supporting data, strongly suggest that ants transfer information on their mutualists during trophallactic interactions. © 2017 The Author(s).

  13. Mutualistic co-evolution of type III effector genes in Sinorhizobium fredii and Bradyrhizobium japonicum.

    Directory of Open Access Journals (Sweden)

    Jeffrey A Kimbrel

    2013-02-01

    Full Text Available Two diametric paradigms have been proposed to model the molecular co-evolution of microbial mutualists and their eukaryotic hosts. In one, mutualist and host exhibit an antagonistic arms race and each partner evolves rapidly to maximize their own fitness from the interaction at potential expense of the other. In the opposing model, conflicts between mutualist and host are largely resolved and the interaction is characterized by evolutionary stasis. We tested these opposing frameworks in two lineages of mutualistic rhizobia, Sinorhizobium fredii and Bradyrhizobium japonicum. To examine genes demonstrably important for host-interactions we coupled the mining of genome sequences to a comprehensive functional screen for type III effector genes, which are necessary for many Gram-negative pathogens to infect their hosts. We demonstrate that the rhizobial type III effector genes exhibit a surprisingly high degree of conservation in content and sequence that is in contrast to those of a well characterized plant pathogenic species. This type III effector gene conservation is particularly striking in the context of the relatively high genome-wide diversity of rhizobia. The evolution of rhizobial type III effectors is inconsistent with the molecular arms race paradigm. Instead, our results reveal that these loci are relatively static in rhizobial lineages and suggest that fitness conflicts between rhizobia mutualists and their host plants have been largely resolved.

  14. Stabilization of erodible slopes with geofibers and nontraditional liquid additives.

    Science.gov (United States)

    2013-05-01

    Instability of erodible slopes due to extreme climate events and of permafrost slopes due degradation and thawing is a significant : engineering problem for northern transportation infrastructure. Engineers continually look for mitigation alternative...

  15. 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.

  16. Ants Learn Aphid Species as Mutualistic Partners: Is the Learning Behavior Species-Specific?

    Science.gov (United States)

    Hayashi, Masayuki; Nakamuta, Kiyoshi; Nomura, Masashi

    2015-12-01

    In ant-aphid associations, many aphid species provide ants with honeydew and are tended by ants, whereas others are never tended and are frequently preyed upon by ants. In these relationships, ants must have the ability to discriminate among aphid species, with mutualistic aphids being accepted as partners rather than prey. Although ants reportedly use cuticular hydrocarbons (CHCs) of aphids to differentiate between mutualistic and non-mutualistic species, it is unclear whether the ability to recognize mutualistic aphid species as partners is innate or involves learning. Therefore, we tested whether aphid recognition by ants depends on learning, and whether the learning behavior is species-specific. When workers of the ant Tetramorium tsushimae had previously tended the cowpea aphid, Aphis craccivora, they were less aggressive toward this species. In addition, ants also reduced their aggressiveness toward another mutualistic aphid species, Aphis fabae, after tending A. craccivora, whereas ants remained aggressive toward the non-mutualistic aphid, Acyrthosiphon pisum, regardless of whether or not they had previous experience in tending A. craccivora. When ants were offered glass dummies treated with CHCs of these aphid species, ants that had tended A. craccivora displayed reduced aggression toward CHCs of A. craccivora and A. fabae. Chemical analyses showed the similarity of the CHC profiles between A. craccivora and A. fabae but not with A. pisum. These results suggest that aphid recognition of ants involves learning, and that the learning behavior may not be species-specific because of the similarity of CHCs between different aphid species with which they form mutualisms.

  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. 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

    Background 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. Methodology/Principal Findings 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. Conclusions/Significance 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. PMID:22912666

  20. Disclosing the double mutualist role of birds on Galápagos

    DEFF Research Database (Denmark)

    Olesen, Jens M; Damgaard, Christian F; Fuster, Francisco

    2018-01-01

    Life on oceanic islands deviate in many ways from that on the mainland. Their biodiversity is relatively poor and some groups are well-represented, others not, especially not insects. A scarcity of insects forces birds to explore alternative food, such as nectar and fruit. In this way, island birds...... of the network, because they are traditionally considered rare. We sampled pollination and seed-dispersal interactions on Galápagos and constructed a plant-bird mutualism network of 108 plant (12% being double mutualists) and 21 bird species (48% being double mutualists), and their 479 interactions, being either...

  1. 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...

  2. 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...

  3. 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 ...

  4. Polychlorinated biphenyl accumulation and hepatic EROD activity in ...

    African Journals Online (AJOL)

    Polychlorinated biphenyl accumulation and hepatic EROD activity in golden grey mullet Liza aurata from Tunis Bay, southern Mediterranean. ... Liza aurata was used as a bioindicator species to monitor contamination by organic xenobiotics of estuarine water at the outlet of Khélij channel [canal], Tunisia, from November ...

  5. 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 ...

  6. Effects of soil physical properties on erodibility and infiltration ...

    African Journals Online (AJOL)

    This study looked at the physical properties of soil of selected areas of Gidan Kwano campus of Federal University of Technology Minna, Nigeria and their effects on erodibility and infiltration parameters. Infiltration rate of the selected areas were conducted using a double ring infiltrometer and soil samples collected at ...

  7. Prioritization of Soil Conservation Measures using Erodibility Indices

    Indian Academy of Sciences (India)

    26

    susceptibility to erosion. The trends of indices were generated by IDW interpolation method to .... some studies indicated relationship between erodibility and dispersion rate, water retaining capacity index and ... Soil samples were collected from 0-10 cm depth randomly; keeping spatial distance as random variable from ...

  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 the ...

  9. 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.

  10. 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.

  11. 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.

  12. Ants Use Partner Specific Odors to Learn to Recognize a Mutualistic Partner

    Science.gov (United States)

    Hojo, Masaru K.; Yamamoto, Ari; Akino, Toshiharu; Tsuji, Kazuki; Yamaoka, Ryohei

    2014-01-01

    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. PMID:24489690

  13. 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.

  14. Three-way interactions among ectomycorrhizal mutualists, scale insects, and resistant and susceptible pinyon pines

    Energy Technology Data Exchange (ETDEWEB)

    Gehring, C.A.; Cobb, N.S.; Whitham, T.G. [Northern Arizona Univ., Flagstaff, AZ (United States)

    1997-05-01

    Herbivores and mycorrhizal fungi are important associates of most plants, but little is known about how these organisms interact. In a 9-yr experiment, we examined how the pinyon needle scale (Matsucoccus acalyptus) affects and is affected by the ectomycorrhizal mutualists found on the roots of scale-resistant and -susceptible pinyon pines (Pinus edulis). Three major results emerged. First, removal experiments demonstrated that scales negatively affected ectomycorrhiza. Second, although ectomycorrhiza could either positively or negatively influence scale performance by improving plant vigor or increasing plant investment in antiherbivore defenses, we found no ectomycorrhizal effect on scale mortality when we experimentally enhanced levels of ectomycorrhiza. This represented the first test of whether ectomycorrhiza promote plant resistance and contrasted with studies showing that arbuscular mycorrhiza negatively affected herbivores. Third, pinyon resistance to scales mediated the asymmetrical interaction between fungal mutualists and scale herbivores. High scale densities suppressed ectomycorrhizal colonization, but only on trees susceptible to scales. Similarities between mycorrhiza-herbivore interactions and competitive interactions among herbivores suggest broader generalities in the way aboveground herbivores interact with belowground plant associates. However, because mycorrhiza are mutualists, mycorrhiza-herbivore interactions do not fit within traditional competition paradigms. The widespread occurrence and importance of both herbivores and mycorrhiza argue for incorporating their interactions into ecological theory. 53 refs., 4 figs.

  15. Mutualistic mimicry and filtering by altitude shape the structure of Andean butterfly communities.

    Science.gov (United States)

    Chazot, Nicolas; Willmott, Keith R; Santacruz Endara, Paola G; Toporov, Alexandre; Hill, Ryan I; Jiggins, Chris D; Elias, Marianne

    2014-01-01

    Both the abiotic environment and abiotic interactions among species contribute to shaping species assemblages. While the roles of habitat filtering and competitive interactions are clearly established, less is known about how positive interactions, whereby species benefit from the presence of one another, affect community structure. Here we assess the importance of positive interactions by studying Andean communities of butterflies that interact mutualistically via Müllerian mimicry. We show that communities at similar altitudes have a similar phylogenetic composition, confirming that filtering by altitude is an important process. We also provide evidence that species that interact mutualistically (i.e., species that share the same mimicry wing pattern) coexist at large scales more often than expected by chance. Furthermore, we detect an association between mimicry structure and altitude that is stronger than expected even when phylogeny is corrected for, indicating adaptive convergence for wing pattern and/or altitudinal range driven by mutualistic interactions. Positive interactions extend far beyond Müllerian mimicry, with many examples in plants and animals, and their role in the evolution and assembly of communities may be more pervasive than is currently appreciated. Our findings have strong implications for the evolution and resilience of community structure in a changing world.

  16. Introduced fire ants can exclude native ants from critical mutualist-provided resources.

    Science.gov (United States)

    Wilder, Shawn M; Barnum, Thomas R; Holway, David A; Suarez, Andrew V; Eubanks, Micky D

    2013-05-01

    Animals frequently experience resource imbalances in nature. For ants, one resource that may be particularly valuable for both introduced and native species is high-carbohydrate honeydew from hemipteran mutualists. We conducted field and laboratory experiments: (1) to test if red imported fire ants (Solenopsis invicta) competed with native ants for access to mutualisms with aphids, and (2) to quantify the effects of aphid honeydew presence or absence on colony growth of native ants. We focused on native dolichoderine ants (Formicidae, Dolichoderinae) because they are abundant ants that have omnivorous diets that frequently include mutualist-provided carbohydrates. At two sites in the southeastern US, native dolichoderine ants were far less frequent, and fire ants more frequent, at carbohydrate baits than would be expected based on their frequency in pitfall traps. A field experiment confirmed that a native ant species, Dorymyrmex bureni, was only found tending aphids when populations of S. invicta were suppressed. In the laboratory, colonies of native dolichoderine ants with access to both honeydew and insect prey had twice as many workers and over twice as much brood compared to colonies fed only ad libitum insect prey. Our results provide the first experimental evidence that introduced ants compete for access to mutualist-provided carbohydrates with native ants and that these carbohydrates represent critical resources for both introduced and native ants. These results challenge traditional paradigms of arthropod and ant nutrition and contribute to growing evidence of the importance of nutrition in mediating ecological interactions.

  17. Reliability assessment of reserved water disposal with erodible fuse plug

    Directory of Open Access Journals (Sweden)

    Kosichenko Yuriy Mikhaylovich

    Full Text Available Water disposal constructions are one of the most responsible constructions of reservoir hydrosystem, that’s why the a lot of attention was always paid to the problems of estimating and providing their reliability and safety. The most important function of such objects is providing reliability and safety of other hydraulic constructions and economic assets in afterbay and water head. The authors offer estimation method for reliability and faultless performance of reserved water disposal with erodible fuse plug on low-head water development. In order to estimate the reliability of reserved water disposal with erodible fuse plug the Bayesian treatment was used. The calculation of diagnoses (states of reserved water disposal isoffered in case of diagnostic properties k 1 and k 2. One of the main demands placed onreserved water disposals is erosion of soil plug in case of flood discharge exeedance over the estimated frequency with the full opening of the waste sluice.

  18. National Highway Alignment from Namakkal to Erode Using GIS

    OpenAIRE

    T. Subramani; S.Krishnan

    2014-01-01

    The vision of the Highway Alignment is to increase the capacity, connectivity, efficiency and safety of the Highways System so as to enable balanced socioeconomic development of all sections of the people and all regions from NAMAKKAL to ERODE via and to reduce the traffic and travelling of the state. It is to establish shortest path for road network time in the roads which provide a better and comfortable base for updating the traffic and other related information in road adm...

  19. 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.

  20. 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.

  1. 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.

  2. 75 FR 75961 - Notice of Implementation of the Wind Erosion Prediction System for Soil Erodibility System...

    Science.gov (United States)

    2010-12-07

    ... Wind Erosion Prediction System for Soil Erodibility System Calculations for the Natural Resources... Erosion Prediction System (WEPS) for soil erodibility system calculations scheduled for implementation for... Erosion Equation (WEQ) where applicable. DATES: Effective Date: This is effective December 7, 2010...

  3. 77 FR 74167 - Information Collection Request: Highly Erodible Land Conservation and Wetland Conservation

    Science.gov (United States)

    2012-12-13

    ... Farm Service Agency Information Collection Request: Highly Erodible Land Conservation and Wetland Conservation AGENCIES: Farm Service Agency, USDA. ACTION: Notice; request for comments. SUMMARY: In accordance... associated with Highly Erodible Land Conservation and Wetland Conservation certification requirements. This...

  4. 7 CFR 12.21 - Identification of highly erodible lands criteria.

    Science.gov (United States)

    2010-01-01

    ... CONSERVATION Highly Erodible Land Conservation § 12.21 Identification of highly erodible lands criteria. (a... is explained in the paper by Woodruff, N.P., and F. H. Siddaway, 1965, “A Wind Erosion Equation...

  5. 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...

  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. The Piriformospora indica effector PIIN_08944 promotes the mutualistic Sebacinalean symbiosis

    Directory of Open Access Journals (Sweden)

    Fidele Ndifor Akum

    2015-10-01

    Full Text Available Pathogenic and mutualistic microbes actively suppress plant defense by secreting effector proteins to manipulate the host responses for their own benefit. Current knowledge about fungal effectors has been mainly derived from biotrophic and hemibiotrophic plant pathogenic fungi and oomycetes with restricted host range. We studied colonization strategies of the root endophytic basidiomycete Piriformospora indica that colonizes a wide range of plant species thereby establishing long-term mutualistic relationships. The release of P. indica’s genome helped to identify hundreds of genes coding for candidate effectors and provides an opportunity to investigate the role of those proteins in a mutualistic symbiosis. We demonstrate that the candidate effector PIIN_08944 plays a crucial role during fungal colonization of Arabidopsis thaliana roots. PIIN_08944 expression was detected during chlamydospore germination, and fungal deletion mutants (Pi∆08944 showed delayed root colonization. Constitutive over-expression of PIIN_08944 in Arabidopsis rescued the delayed colonization phenotype of the deletion mutant. PIIN_08944-expressing Arabidopsis showed a reduced expression of flg22-induced marker genes of pattern-triggered immunity (PTI and the salicylic acid (SA defense pathway, and expression of PIIN_08944 in barley reduced the burst of reactive oxygen species (ROS triggered by flg22 and chitin. These data suggest that PIIN_08944 contributes to root colonization by P. indica by interfering with SA-mediated basal immune responses of the host plant. Consistent with this, PIIN_08944-expressing Arabidopsis also supported the growth of the biotrophic oomycete Hyaloperonospora arabidopsidis while growth of the necrotrophic fungi Botrytis cinerea on Arabidopsis and Fusarium graminearum on barley was not affected.

  8. 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.

  9. 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

  10. 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.

  11. Limiting cheaters in mutualism: evidence from hybridization between mutualist and cheater yucca moths.

    Science.gov (United States)

    Segraves, Kari A; Althoff, David M; Pellmyr, Olle

    2005-10-22

    Mutualisms are balanced antagonistic interactions where both species gain a net benefit. Because mutualisms generate resources, they can be exploited by individuals that reap the benefits of the interaction without paying any cost. The presence of such 'cheaters' may have important consequences, yet we are only beginning to understand how cheaters evolve from mutualists and how their evolution may be curtailed within mutualistic lineages. The yucca-yucca moth pollination mutualism is an excellent model in this context as there have been two origins of cheating from within the yucca moth lineage. We used nuclear and mitochondrial DNA markers to examine genetic structure in a moth population where a cheater species is parapatric with a resident pollinator. The results revealed extensive hybridization between pollinators and cheaters. Hybrids were genetically intermediate to parental populations, even though all individuals in this population had a pollinator phenotype. The results suggest that mutualisms can be stable in the face of introgression of cheater genes and that the ability of cheaters to invade a given mutualism may be more limited than previously appreciated.

  12. 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.

  13. Linking biodiversity to mutualistic networks – woody species and ectomycorrhizal fungi

    Directory of Open Access Journals (Sweden)

    Ecaterina Fodor

    2013-05-01

    Full Text Available Mutualistic interactions are currently mapped by bipartite networkswith particular architecture and properties. The mycorrhizae connectthe trees and permit them to share resources, therefore relaxing thecompetition. Ectomycorrhizal macrofungi associated with woody species(Quercus robur, Q. cerris, Q. petraea, Tilia tomentosa, Carpinus betulus, Corylus avellana, and Q. pubescens growing in a temperate, broadleaved mixed forest, from a hilly area near the city of Cluj–Napoca, central Romania were included in a bipartite mutualistic network. Community structure was investigated using several network metrics, modularity and nestedness algorithms in conjunction with C-score index cluster analysis and nonmetric multidimensional scaling (the Kulczynski similarity was index used as most appropriate metric selected by minimal stress criterion. The results indicate that the network presents high asymmetry (hosts are outnumbered by mycobionts at a great extent, high connectance, low modularity, andhigh nestedness, competition playing a secondary role in community assemblage (non significant difference between simulated and observed Cscore.The nestedness pattern is non-random and is comparable to previouslypublished results for other similar interactions containing plants. Inthe proposed network, woody species function exclusively as generalists. Modularity analysis is a finer tool were identifying species roles than centrality measures, however, the two types of algorithms permit the separation of species according to their roles as for example connectors (generalist species and ultraperipheral species (specialists. Supergeneralist woody species function as hubs for the diverse ectomycorrhizal community while supergeneralistectomycorrhizal fungi glue the hubs into a coherent aggregate.

  14. Detecting phylogenetic signal in mutualistic interaction networks using a Markov process model.

    Science.gov (United States)

    Minoarivelo, H O; Hui, C; Terblanche, J S; Pond, S L Kosakovsky; Scheffler, K

    2014-10-01

    Ecological interaction networks, such as those describing the mutualistic interactions between plants and their pollinators or between plants and their frugivores, exhibit non-random structural properties that cannot be explained by simple models of network formation. One factor affecting the formation and eventual structure of such a network is its evolutionary history. We argue that this, in many cases, is closely linked to the evolutionary histories of the species involved in the interactions. Indeed, empirical studies of interaction networks along with the phylogenies of the interacting species have demonstrated significant associations between phylogeny and network structure. To date, however, no generative model explaining the way in which the evolution of individual species affects the evolution of interaction networks has been proposed. We present a model describing the evolution of pairwise interactions as a branching Markov process, drawing on phylogenetic models of molecular evolution. Using knowledge of the phylogenies of the interacting species, our model yielded a significantly better fit to 21% of a set of plant - pollinator and plant - frugivore mutualistic networks. This highlights the importance, in a substantial minority of cases, of inheritance of interaction patterns without excluding the potential role of ecological novelties in forming the current network architecture. We suggest that our model can be used as a null model for controlling evolutionary signals when evaluating the role of other factors in shaping the emergence of ecological networks.

  15. 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.

  16. 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.

  17. Effect of erodent particles on the erosion of metal specimens

    Energy Technology Data Exchange (ETDEWEB)

    Razzaque, M. Mahbubur, E-mail: mmrazzaque@me.buet.ac.bd; Alam, M. Khorshed; Khan, M. Ishak, E-mail: ishak.buet@gmail.com [Department of Mechanical Engineering Bangladesh University of Engineering and Technology (BUET), Dhaka (Bangladesh)

    2016-07-12

    This paper presents the experimental results of the measurement of erosion rate of carbon steel specimens in sand water slurry system in a slurry pot tester. Sylhet sand has been sieved to get three sizes of erodent particles; namely, less than 250 micron, 250 to 590 micron and 590 to 1190 micron. Experiments are done with three sand concentrations (10%, 15% and 20%). The rate of erosion of the carbon steel specimens is measured as the loss of weight per unit surface area per unit time under the dynamic action of solid particles. The eroded surfaces of the specimens are examined using Scanning Electron Microscopy (SEM) to visualize the impact of the slurry of various conditions. It is seen that irrespective of the particle size the rate of erosion increases with the increase of slurry concentration. This increment of erosion rate at high concentration is high for large particles. High erosion rate is observed in case of large sand particles. In case of small and fine particles erosion rate is small because of low impact energy as well as the wastage of energy to overcome the hindrance of the finer particles before striking on the specimen surface.

  18. Effect of erodent particles on the erosion of metal specimens

    Science.gov (United States)

    Razzaque, M. Mahbubur; Alam, M. Khorshed; Khan, M. Ishak

    2016-07-01

    This paper presents the experimental results of the measurement of erosion rate of carbon steel specimens in sand water slurry system in a slurry pot tester. Sylhet sand has been sieved to get three sizes of erodent particles; namely, less than 250 micron, 250 to 590 micron and 590 to 1190 micron. Experiments are done with three sand concentrations (10%, 15% and 20%). The rate of erosion of the carbon steel specimens is measured as the loss of weight per unit surface area per unit time under the dynamic action of solid particles. The eroded surfaces of the specimens are examined using Scanning Electron Microscopy (SEM) to visualize the impact of the slurry of various conditions. It is seen that irrespective of the particle size the rate of erosion increases with the increase of slurry concentration. This increment of erosion rate at high concentration is high for large particles. High erosion rate is observed in case of large sand particles. In case of small and fine particles erosion rate is small because of low impact energy as well as the wastage of energy to overcome the hindrance of the finer particles before striking on the specimen surface.

  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

    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...... 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...... 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. Effects of erodant particle shape and various heat treatments on erosion resistance of plain carbon steel

    Science.gov (United States)

    Salik, J.; Buckley, D. H.

    1981-01-01

    Erosion tests were conducted on 1045 steel samples which had been subjected to different heat treatments. The weight of material removed upon erosion with glass beads and crushed glass was measured. The data show that there is no correlation between hardness and erosion resistance. The erosion rate was strongly dependent on the shape of erodant particles, being an order of magnitude higher for erosion with crushed glass than with glass beads. Heat treatment had a profound effect on the erosion resistance when the erodant particles were glass beads but little or no effect when the particles were crushed glass. It is thus concluded that different mechanisms of material removal are involved with these two erodants. This conclusion is supported by the surface morphology of annealed 1045 steel samples which had been eroded by these two types of erodant particles. SEM micrographs of the eroded surfaces show that for erosion with glass beads it is deformation induced fracture of surface layers.

  2. Trifolium species associate with a similar richness of soil-borne mutualists in their introduced and native ranges

    NARCIS (Netherlands)

    McGinn, K.J.; Putten, van der W.H.; Duncan, R.P.; Shelby, Natasha; Weser, Carolin; Hulme, P.E.

    2016-01-01

    Aim: While plant species introduced to new regions may benefit from escaping natural enemies, their success may be impaired by losing key mutualists. We aimed to elucidate whether a selection of annual and perennial Trifolium (clover) species have lost associations with nitrogen-fixing bacteria

  3. Symbiont recognition of mutualistic bacteria by Acromyrmex leaf-cutting ants

    DEFF Research Database (Denmark)

    Zhang, Mingzi; Poulsen, Michael; Currie, Cameron R

    2007-01-01

    Symbiont choice has been proposed to play an important role in shaping many symbiotic relationships, including the fungus-growing ant-microbe mutualism. Over millions of years, fungus-growing ants have defended their fungus gardens from specialized parasites with antibiotics produced...... by an actinomycete bacterial mutualist (genus Pseudonocardia). Despite the potential of being infected by phylogenetically diverse strains of parasites, each ant colony maintains only a single Pseudonocardia symbiont strain, which is primarily vertically transmitted between colonies by the founding queens....... In this study, we show that Acromyrmex leaf-cutter ants are able to differentiate between their native actinomycete strain and a variety of foreign strains isolated from sympatric and allopatric Acromyrmex species, in addition to strains originating from other fungus-growing ant genera. The recognition...

  4. Ethylene Supports Colonization of Plant Roots by the Mutualistic Fungus Piriformospora indica

    Science.gov (United States)

    Khatabi, Behnam; Molitor, Alexandra; Lindermayr, Christian; Pfiffi, Stefanie; Durner, Jörg; von Wettstein, Diter; Kogel, Karl-Heinz; Schäfer, Patrick

    2012-01-01

    The mutualistic basidiomycete Piriformospora indica colonizes roots of mono- and dicotyledonous plants, and thereby improves plant health and yield. Given the capability of P. indica to colonize a broad range of hosts, it must be anticipated that the fungus has evolved efficient strategies to overcome plant immunity and to establish a proper environment for nutrient acquisition and reproduction. Global gene expression studies in barley identified various ethylene synthesis and signaling components that were differentially regulated in P. indica-colonized roots. Based on these findings we examined the impact of ethylene in the symbiotic association. The data presented here suggest that P. indica induces ethylene synthesis in barley and Arabidopsis roots during colonization. Moreover, impaired ethylene signaling resulted in reduced root colonization, Arabidopsis mutants exhibiting constitutive ethylene signaling, -synthesis or ethylene-related defense were hyper-susceptible to P. indica. Our data suggest that ethylene signaling is required for symbiotic root colonization by P. indica. PMID:22536394

  5. 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.

  6. Three-way interactions among mutualistic mycorrhizal fungi, plants, and plant enemies: hypotheses and synthesis.

    Science.gov (United States)

    Bennett, Alison E; Alers-Garcia, Janice; Bever, James D

    2006-02-01

    A number of studies have shown that an association with mycorrhizal fungi can alter the outcome of interactions between plants and their enemies. While the directions of these effects vary, their strength suggests the need for greater attention to multispecies interactions among plant enemies, plants, and mycorrhizal fungi. We recognize that mycorrhizal fungi could effect plant enemies by improving plant nutrition, modifying plant tolerance, or modifying plant defenses. In addition, mycorrhizal fungi could directly interfere with pathogen infection, herbivory, or parasitism by occupying root space. We formalize these alternative outcomes of multispecies interactions and explore the long-term dynamics of the plant-enemy interactions based on these different scenarios using a general model of interactions between plants and plant enemies. We then review the literature in terms of the assumptions of the alternative mechanisms and the predictions of these models. Through this effort, we identify new directions in the study of tritrophic interactions between enemies, plants, and soil mutualists.

  7. 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.

  8. Host plant use by competing acacia-ants: mutualists monopolize while parasites share hosts.

    Science.gov (United States)

    Kautz, Stefanie; Ballhorn, Daniel J; Kroiss, Johannes; Pauls, Steffen U; Moreau, Corrie S; Eilmus, Sascha; Strohm, Erhard; Heil, Martin

    2012-01-01

    Protective ant-plant mutualisms that are exploited by non-defending parasitic ants represent prominent model systems for ecology and evolutionary biology. The mutualist Pseudomyrmex ferrugineus is an obligate plant-ant and fully depends on acacias for nesting space and food. The parasite Pseudomyrmex gracilis facultatively nests on acacias and uses host-derived food rewards but also external food sources. Integrative analyses of genetic microsatellite data, cuticular hydrocarbons and behavioral assays showed that an individual acacia might be inhabited by the workers of several P. gracilis queens, whereas one P. ferrugineus colony monopolizes one or more host trees. Despite these differences in social organization, neither of the species exhibited aggressive behavior among conspecific workers sharing a tree regardless of their relatedness. This lack of aggression corresponds to the high similarity of cuticular hydrocarbon profiles among ants living on the same tree. Host sharing by unrelated colonies, or the presence of several queens in a single colony are discussed as strategies by which parasite colonies could achieve the observed social organization. We argue that in ecological terms, the non-aggressive behavior of non-sibling P. gracilis workers--regardless of the route to achieve this social structure--enables this species to efficiently occupy and exploit a host plant. By contrast, single large and long-lived colonies of the mutualist P. ferrugineus monopolize individual host plants and defend them aggressively against invaders from other trees. Our findings highlight the necessity for using several methods in combination to fully understand how differing life history strategies affect social organization in ants.

  9. Linking biodiversity to mutualistic networks – woody species and ectomycorrhizal fungi

    Directory of Open Access Journals (Sweden)

    Ecaterina Fodor

    2013-07-01

    Full Text Available Mutualistic interactions are currently mapped by bipartite networks with particular architecture and properties. The mycorrhizae connect the trees and permit them to share resources, therefore relaxing the competition. Ectomycorrhizal macrofungi associated with woody species (Quercus robur, Q. cerris, Q. petraea, Tilia tomentosa, Carpinus betulus, Corylus avellana, and Q. pubescens growing in a temperate, broadleaved mixed forest, from a hilly area near the city of Cluj–Napoca, central Romania were included in a bipartite mutualistic network. Community structure was investigated using several network metrics, modularity and nestedness algorithms in conjunction with C-score index cluster analysis and nonmetric multidimensional scaling (the Kulczynski similarity was index used as most appropriate metric selected by minimal stress criterion. The results indicate that the network presents high asymmetry (hosts are outnumbered by mycobionts at a great extent, high connectance, low modularity, and high nestedness, competition playing a secondary role in community assemblage (non significant difference between simulated and observed C-score. The nestedness pattern is non-random and is comparable to previously published results for other similar interactions containing plants. In the proposed network, woody species function exclusively as generalists. Modularity analysis is a finer tool were identifying species roles than centrality measures, however, the two types of algorithms permit the separation of species according to their roles as for example connectors (generalist species and ultraperipheral species (specialists. Supergeneralist woody species function as hubs for the diverse ectomycorrhizal community while supergeneralist ectomycorrhizal fungi glue the hubs into a coherent aggregate. 

  10. 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.

  11. 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 (Pwear (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.

  12. 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

  13. 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…

  14. Soil aggregate stability and erodibility in different gully sites in parts ...

    African Journals Online (AJOL)

    This paper assesses soil aggregate stability and erodibility in different gully sites in parts of Zaria, Kaduna State, Nigeria with the aim to provide quantitative information on the variation of some soil properties and their interaction with eroding agents and how this affects soil erosion on the sites. The gullies selected are found ...

  15. Developing a parameterization approach of soil erodibility for the Rangeland Hydrology and Erosion Model (RHEM)

    Science.gov (United States)

    Soil erodibility is a key factor for estimating soil erosion using physically based models. In this study, a new parameterization approach for estimating erodibility was developed for the Rangeland Hydrology and Erosion Model (RHEM). The approach uses empirical equations that were developed by apply...

  16. Developing soil erodibility prediction equations for the Rangeland Hydrology and Erosion Model (RHEM)

    Science.gov (United States)

    Soil erodibility is a key factor for estimating soil erosion using physically based models. In this study, a new parameterization approach for estimating erodibility was developed for the Rangeland Hydrology and Erosion Model (RHEM). The approach uses empirical equations that were developed by apply...

  17. 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.

  18. 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.

  19. 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

  20. 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)

  1. Surface Eroding, Semicrystalline Polyanhydrides via Thiol-Ene "Click" Photopolymerization.

    Science.gov (United States)

    Poetz, Katie L; Mohammed, Halimatu S; Shipp, Devon A

    2015-05-11

    Surface eroding and semicrystalline polyanhydrides, with tunable erosion times and drug delivery pharmacokinetics largely dictated by erosion, are produced easily with thiol-ene "click" polymerization. This strategy yields both linear and cross-linked network polyanhydrides that are readily and fully cured within minutes using photoinitiation, can contain up to 60% crystallinity, and have tensile moduli up to 25 MPa for the compositions studied. Since they readily undergo hydrolysis and exhibit the oft-preferred surface erosion mechanism, they may be particularly useful in drug delivery applications. The polyanhydrides were degraded under pseudophysiological conditions and cylindrical samples (10 mm diameter × 5 mm height) were completely degraded within ∼10 days, with the mass-time profile being linear for much of this time after a ∼24 h induction period. Drug release studies, using lidocaine as a model, showed pharmacokinetics that displayed a muted burst release in the early stages of erosion, but then a delayed release profile that is closely correlated to the erosion kinetics. Furthermore, cytotoxicity studies of the linear and cross-linked semicrystalline polyanhydrides, and degradation products, against fibroblast cells indicate that the materials have good cytocompatibility. Overall, cells treated with up to 2500 mg/L of the semicrystalline polyanhydrides and degradation products show >90% human dermal fibroblast adult (HDFa) cell viability indicative of good cytocompatibility.

  2. Development of Surface Eroding Thermocouples in DIII-D

    Science.gov (United States)

    Ren, Jun; Donovan, David; Watkins, Jon; Wang, Huiqian; Rudakov, Dmitry; Murphy, Christopher; Unterberg, Ezekial; Thomas, Dan; Boivin, Rejean

    2017-10-01

    The Surface Eroding Thermocouple (SETC) is a specialized diagnostic for characterizing the surface temperature evolution with a high temporal resolution ( 1ms) which is especially useful in areas unobservable by line-of-sight diagnostics (e.g. IR cameras). Recently, SETCs were tested in DiMES and successfully acquired temperature signals during strike point sweeps on the lower divertor shelf. We observed that the SETCs have a sub-10 ms time response and is sufficient to resolve ELM heat pulses. Preliminary analysis shows heat fluxes measured by SETCs and IR camera agree within 20%. Comparison of SETCs, calorimeters and Langmuir probe also show good agreement. We plan to implement an array of SETCs embedded in the tiles forming the new DIII-D small angle slot (SAS) divertor. Strategies to improve the SNR of these SETCs through testing in DiMES before the final installation will be discussed. This work was supported by the US Department of Energy under DE-SC0016318 (UTK), DE-AC05-00OR22725 (ORNL), DE-FG02-07ER54917 (UCSD), DE-FC02-04ER54698 (GA), DE-AC04-94AL85000 (SNL).

  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. 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.

  5. 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.

  6. 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,...

  7. Stage-dependent ethoxyresorufin-O-deethylase (EROD) in vivo activity in medaka (Oryzias latipes) embryos.

    Science.gov (United States)

    González-Doncel, Miguel; Carbonell, Gregoria; San Segundo, Laura; Sastre, Salvador; Beltrán, Eulalia M; Fernández-Torija, Carlos

    2015-09-01

    Using medaka (Oryzias latipes) embryos, this study aimed to quantitatively characterize the stage-dependent in vivo ethoxyresorufin-O-deethylase (EROD) as indicator of cytochrome P4501A (CYP1A) activity. Embryos were challenged for 24-h to an agonist (β-naphthoflavone [BNF], 2.5, 5, 10, and 20 μg L(-1)) or to its combination (2.5 μg L(-1)) with an antagonist (α-naphthoflavone [ANF], 25, 50, 100, and 200 μg L(-1)), initiated at four different developmental time points (1, 3, 6, and 9 d post-fertilization [dpf]). Respective induction and competitive inhibition were evaluated over fluorescent images of whole embryo (nonorgan-specific [NOS] EROD activity) and gallbladder (organ-specific [OS] EROD activity). Both flavonoids showed signs of stability in solution. Generally speaking, the mean fluorescence intensity (MFI) values for NOS EROD increased with BNF concentration and exposure challenge. BNF co-exposure with ⩾50 μg ANF L(-1) during the 1-2 and 3-4 dpf challenges lowered NOS EROD to undetectably induced levels. Significant increments in MFIs for OS-EROD were seen from exposures to ⩾2.5 μg BNF L(-1), peaking during the 6-7 dpf challenge regardless of BNF concentration. The simultaneous BNF/ANF incubation showed competitive inhibition for OS EROD activity, although levels were generally detectably induced during all challenges and at all ANF concentrations. The morphometric in vivo gallbladder analysis indicated significant dilation in the 10 dpf-old embryos co-exposed to BNF and 200 μg ANF L(-1). This quantitative approach can be used successfully at 4 dpf at the NOS-EROD or OS-EROD levels, although the NOS-EROD response was sensitive enough to induction or inhibition, even at 2 dpf. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. A Comparison of Thresholds: Shields and Erodibility Index

    Science.gov (United States)

    Humphries, R. P.; Annandale, G. W.; Rock, A. J.

    2015-12-01

    The threshold between stasis and mobility, and the forms and processes associated with the interfacial instabilities it defines, is a fundamental component of most morphodynamic systems. Scientists and engineers who focus on the interface of the earth's dynamic surface and the turbulent fluids of the atmosphere and hydrosphere, have approached this interface from a diversity of perspectives. In the field of sediment transport, Shield's 1936 paper stands as a benchmark for the theoretical understanding of the threshold of incipient motion of non-cohesive granular transport. However, in processes such as the erosion of cohesive material or bedrock erosion, consensus has yet to be reached among researchers, as to which method most aptly encompasses these processes. The lack of consensus is reasonable, considering the diversity of the applications, and implications, of interface dynamics. When thresholds may depend on the sequence of antecedent conditions, as in cohesive sediment entrainment, or the time scale of perception ranges from many Hertz to geologic eras, as in the processes of rock scour, a diversity of conceptual models is to be anticipated. In Scour Technology (Annandale 2006), the Erodibility Index Method (EIM) is presented as a threshold paradigm that spans the breadth of all earth materials that may experiences erosion by fluid forces. The authors present a comparison of the modern expression of the benchmark theoretical understanding of the threshold of incipient motion of non-cohesive granular material with the EIM. Results illustrate that each threshold can provide insight into the other and that the Shields parameter can be expressed within the vocabulary of the EIM.

  9. Effects of nitrogen limitation on Dunaliella sp.–Alteromonas sp. interactions: from mutualistic to competitive relationships.

    OpenAIRE

    Le Chevanton, Myriam; Garnier, Matthieu; Lukomska, Ewa; Schreiber, Nathalie; Cadoret, Jean-paul; Saint-jean, Bruno; Bougaran, Gael

    2016-01-01

    Interactions between photosynthetic and non-photosynthetic microorganisms play an essential role in natural aquatic environments and the contribution of bacteria and microalgae to the nitrogen cycle can lead to both competitive and mutualistic relationships. Nitrogen is considered to be, with phosphorus and iron, one of the main limiting nutrients for primary production in the oceans and its availability experiences large temporal and geographical variations. For these reasons, it is importan...

  10. Seed trait-mediated selection by rodents affects mutualistic interactions and seedling recruitment of co-occurring tree species.

    Science.gov (United States)

    Zhang, Hongmao; Yan, Chuan; Chang, Gang; Zhang, Zhibin

    2016-02-01

    As mutualists, seed dispersers may significantly affect mutualistic interactions and seedling recruitment of sympatric plants that share similar seed dispersers, but studies are rare. Here, we compared seed dispersal fitness in two co-occurring plant species (Armeniaca sibirica and Amygdalus davidiana) that inhabit warm temperate deciduous forest in northern China. We tested the hypothesis that seed trait-mediated selection by rodents may influence mutualistic interactions with rodents and then seedling establishment of co-occurring plant species. A. davidiana seeds are larger and harder (thick endocarps) than A. sibirica seeds, but they have similar levels of nutrients (crude fat, crude protein), caloric value and tannin. More A. sibirica seedlings are found in the field. Semi-natural enclosure tests indicated that the two seed species were both harvested by the same six rodent species, but that A. sibirica had mutualistic interactions (scatter hoarding) with four rodent species (Apodemus peninsulae, A. agrarius, Sciurotamias davidianus, Tamias sibiricus), and A. davidiana with only one (S. davidianus). Tagged seed dispersal experiments in the field indicated that more A. sibirica seeds were scatter-hoarded by rodents, and more A. sibirica seeds survived to the next spring and became seedlings. A. sibirica seeds derive more benefit from seed dispersal by rodents than A. davidiana seeds, particularly in years with limited seed dispersers, which well explained the higher seedling recruitment of A. sibirica compared with that of A. davidiana under natural conditions. Our results suggest that seed dispersers may play a significant role in seedling recruitment and indirect competition between co-occurring plant species.

  11. 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.

  12. Microbial Root Mutualists Affect the Predators and Pathogens of Herbivores above Ground: Mechanisms, Magnitudes, and Missing Links

    Directory of Open Access Journals (Sweden)

    Leiling Tao

    2017-12-01

    Full Text Available Tri-trophic interactions among plants, herbivores, and natural enemies of herbivores are common in nature, and are crucial components of trophic cascades and the dynamics of community composition. Plant traits are key determinants of the interactions between herbivores and their natural enemies aboveground, which in turn are affected by soil organisms. Recent years have seen a surge in studies of the interactions between below- and aboveground biota, including descriptions of how microbial root mutualists influence plant traits and herbivore performance. However, concomitant effects on the natural enemies of herbivores remain relatively poorly understood. Here, we review the currently available literature to assess how and when mutualistic root microbes impose significant indirect effects on the performance of predators and pathogens of insect herbivores. We focus on how root microbes influence predator attraction, on-plant foraging efficiency, and the quality of prey tissues. We also consider the underappreciated effects of microbial root mutualists on the growth, transmission, and virulence of insect pathogens. We end by discussing missing links and important directions for future research.

  13. 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.

  14. The endosymbiotic dinoflagellates ( Symbiodinium sp.) of corals are parasites and mutualists

    Science.gov (United States)

    Lesser, M. P.; Stat, M.; Gates, R. D.

    2013-09-01

    The evolutionary success and continued survival of reef-building corals under increasing environmental change will, in part, be determined by the composition of their endosymbiotic dinoflagellate communities ( Symbiodinium sp.). Recent research suggests that differences in the phylotype composition of Symbiodinium in the same host can lead to different outcomes for the host when exposed to similar environmental conditions. One explanation for these observations is that symbioses between corals and Symbiodinium represent a continuum of interaction states that encompass mutualisms and parasitisms consistent with current evolutionary theory developed for other symbiotic systems. Here, we discuss the evidence supporting the existence of a parasitic to mutualistic continuum in Symbiodinium interactions and propose that a consideration of the evolutionary ecology of these associations will advance our understanding of how environmental change will influence the ecological outcomes in these important symbioses. We advocate that a robust taxonomic structure for Symbiodinium sp. and empirical studies on sexual reproduction in Symbiodinium, the stability of interaction states among Symbiodinium symbioses spatially and temporally and how interaction states change as the environment changes will generate data for models that accurately forecast how climate change will influence the persistence of corals and the reefs they structure.

  15. 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.

  16. 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.

  17. Mutualistic mycorrhiza-like symbiosis in the most ancient group of land plants.

    Science.gov (United States)

    Humphreys, Claire P; Franks, Peter J; Rees, Mark; Bidartondo, Martin I; Leake, Jonathan R; Beerling, David J

    2010-11-02

    Over 35 years ago, it was hypothesized that mutualistic symbiotic soil fungi assisted land plants in their initial colonization of terrestrial environments. This important idea has become increasingly established with palaeobotanical and molecular investigations dating the interactions between arbuscular mycorrhizal fungi (AMF) and land plants to at least 400 Ma, but the functioning of analogous partnerships in 'lower' land plants remains unknown. In this study, we show with multifactorial experiments that colonization of a complex thalloid liverwort, a member of the most ancient extant clade of land plants, with AMF significantly promotes photosynthetic carbon uptake, growth and asexual reproduction. Plant fitness increased through fungal-enhanced acquisition of phosphorus and nitrogen from soil, with each plant supporting 100-400 m of AMF mycelia. A simulated CO(2)-rich atmosphere, similar to that of the Palaeozoic when land plants originated, significantly amplified the net benefits of AMF and likely selection pressures for establishment of the symbiosis. Our analyses provide essential missing functional evidence supporting AMF symbionts as drivers of plant terrestrialization in early Palaeozoic land ecosystems.

  18. 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.

  19. 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.

  20. Invasive Species

    Science.gov (United States)

    Invasive species have significantly changed the Great Lakes ecosystem. An invasive species is a plant or animal that is not native to an ecosystem, and whose introduction is likely to cause economic, human health, or environmental damage.

  1. 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

  2. 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

  3. On the ages of resonant, eroded and fossil asteroid families

    Science.gov (United States)

    Milani, Andrea; Knežević, Zoran; Spoto, Federica; Cellino, Alberto; Novaković, Bojan; Tsirvoulis, Georgios

    2017-05-01

    In this work we have estimated 10 collisional ages of 9 families for which for different reasons our previous attempts failed. In general, these are difficult cases that required dedicated effort, such as a new family classifications for asteroids in mean motion resonances, in particular the 1/1 and 2/1 with Jupiter, as well as a revision of the classification inside the 3/2 resonance. Of the families locked in mean motion resonances, by employing a numerical calibration to estimate the Yarkovsky effect in proper eccentricity, we succeeded in determining ages of the families of (1911) Schubart and of the "super-Hilda" family, assuming this is actually a severely eroded original family of (153) Hilda. In the Trojan region we found families with almost no Yarkovsky evolution, for which we could compute only physically implausible ages. Hence, we interpreted their modest dispersions of proper elements as implying that the Trojan asteroid families are fossil families, frozen at their proper elements determined by the original ejection velocity field. We have found a new family, among the Griquas locked in the 2/1 resonance with Jupiter, the family of (11097) 1994 UD1. We have estimated the ages of 6 families affected by secular resonances: families of (5) Astraea, (25) Phocaea, (283) Emma, (363) Padua, (686) Gersuind, and (945) Barcelona. By using in all these cases a numerical calibration method, we have shown that the secular resonances do not affect significantly the secular change of proper a. We have confirmed the existence of the family resulting from cratering on (5) Astraea by computing a new set of resonant proper elements adapted to the resonance g +g5 - 2g6 : this new family has a much larger membership and has a shape compatible with simple collisional models. For the family of (145) Adeona we could estimate the age only after removal of a number of assumed interlopers. With the present paper we have concluded the series dedicated to the determination of

  4. 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...

  5. Lightweight High Temperature Non-Eroding Throat Materials for Propulsion Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovation in this proposed effort is the development of lightweight, non-eroding nozzle materials for use in propulsion systems. Lightweight structures are...

  6. Eroded Coffee Traceability and Its Impact on Export Coffee Prices for Ethiopia

    OpenAIRE

    Leonard Leung

    2014-01-01

    In December 2008, the Ethiopian Commodity Exchange (ECX) opened a new coffee platform that has transformed Ethiopia’s coffee trade. The way ECX handles coffee in a commodity fashion has eroded traceability, a characteristic sought after by overseas coffee buyers. This paper traces the forces that give rise to the commoditization of coffee. An empirical analysis using a dataset on export coffee transactions supports the view that eroded traceability suppresses the export price of non-traceable...

  7. 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 ...

  8. 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

  9. Predators alter community organization of coral reef cryptofauna and reduce abundance of coral mutualists

    Science.gov (United States)

    Stier, A. C.; Leray, M.

    2014-03-01

    Coral reefs are the most diverse marine systems in the world, yet our understanding of the processes that maintain such extraordinary diversity remains limited and taxonomically biased toward the most conspicuous species. Cryptofauna that live deeply embedded within the interstitial spaces of coral reefs make up the majority of reef diversity, and many of these species provide important protective services to their coral hosts. However, we know very little about the processes governing the diversity and composition of these less conspicuous but functionally important species. Here, we experimentally quantify the role of predation in driving the community organization of small fishes and decapods that live embedded within Pocillopora eydouxi, a structurally complex, reef-building coral found widely across the Indo-Pacific. We use surveys to describe the natural distribution of predators, and then, factorially manipulate two focal predator species to quantify the independent and combined effects of predator density and identity on P. eydouxi-dwelling cryptofauna. Predators reduced abundance (34 %), species richness (20 %), and modified species composition. Rarefaction revealed that observed reductions in species richness were primarily driven by changes in abundance. Additionally, the two predator species uniquely affected the beta diversity and composition of the prey assemblage. Predators reduced the abundance and modified the composition of a number of mutualist fishes and decapods, whose benefit to the coral is known to be both diversity- and density-dependent. We predict that the density and identity of predators present within P. eydouxi may substantially alter coral performance in the face of an increased frequency and intensity of natural and anthropogenic stressors.

  10. Responses to Elevated c-di-GMP Levels in Mutualistic and Pathogenic Plant-Interacting Bacteria

    Science.gov (United States)

    Pérez-Mendoza, Daniel; Aragón, Isabel M.; Prada-Ramírez, Harold A.; Romero-Jiménez, Lorena; Ramos, Cayo; Gallegos, María-Trinidad; Sanjuán, Juan

    2014-01-01

    Despite a recent burst of research, knowledge on c-di-GMP signaling pathways remains largely fragmentary and molecular mechanisms of regulation and even c-di-GMP targets are yet unknown for most bacteria. Besides genomics or bioinformatics, accompanying alternative approaches are necessary to reveal c-di-GMP regulation in bacteria with complex lifestyles. We have approached this study by artificially altering the c-di-GMP economy of diverse pathogenic and mutualistic plant-interacting bacteria and examining the effects on the interaction with their respective host plants. Phytopathogenic Pseudomonas and symbiotic Rhizobium strains with enhanced levels of intracellular c-di-GMP displayed common free-living responses: reduction of motility, increased production of extracellular polysaccharides and enhanced biofilm formation. Regarding the interaction with the host plants, P. savastanoi pv. savastanoi cells containing high c-di-GMP levels formed larger knots on olive plants which, however, displayed reduced necrosis. In contrast, development of disease symptoms in P. syringae-tomato or P. syringae-bean interactions did not seem significantly affected by high c-di-GMP. On the other hand, increasing c-di-GMP levels in symbiotic R. etli and R. leguminosarum strains favoured the early stages of the interaction since enhanced adhesion to plant roots, but decreased symbiotic efficiency as plant growth and nitrogen contents were reduced. Our results remark the importance of c-di-GMP economy for plant-interacting bacteria and show the usefulness of our approach to reveal particular stages during plant-bacteria associations which are sensitive to changes in c-di-GMP levels. PMID:24626229

  11. Interactions between mutualist Wigglesworthia and tsetse peptidoglycan recognition protein (PGRP-LB) influence trypanosome transmission.

    Science.gov (United States)

    Wang, Jingwen; Wu, Yineng; Yang, Guangxiao; Aksoy, Serap

    2009-07-21

    Tsetse flies, the sole vectors of African trypanosomes, have coevolved with mutualistic endosymbiont Wigglesworthia glossinidiae. Elimination of Wigglesworthia renders tsetse sterile and increases their trypanosome infection susceptibility. We show that a tsetse peptidoglycan recognition protein (PGRP-LB) is crucial for symbiotic tolerance and trypanosome infection processes. Tsetse pgrp-lb is expressed in the Wigglesworthia-harboring organ (bacteriome) in the midgut, and its level of expression correlates with symbiont numbers. Adult tsetse cured of Wigglesworthia infections have significantly lower pgrp-lb levels than corresponding normal adults. RNA interference (RNAi)-mediated depletion of pgrp-lb results in the activation of the immune deficiency (IMD) signaling pathway and leads to the synthesis of antimicrobial peptides (AMPs), which decrease Wigglesworthia density. Depletion of pgrp-lb also increases the host's susceptibility to trypanosome infections. Finally, parasitized adults have significantly lower pgrp-lb levels than flies, which have successfully eliminated trypanosome infections. When both PGRP-LB and IMD immunity pathway functions are blocked, flies become unusually susceptible to parasitism. Based on the presence of conserved amidase domains, tsetse PGRP-LB may scavenge the peptidoglycan (PGN) released by Wigglesworthia and prevent the activation of symbiont-damaging host immune responses. In addition, tsetse PGRP-LB may have an anti-protozoal activity that confers parasite resistance. The symbiotic adaptations and the limited exposure of tsetse to foreign microbes may have led to the considerable differences in pgrp-lb expression and regulation noted in tsetse from that of closely related Drosophila. A dynamic interplay between Wigglesworthia and host immunity apparently is influential in tsetse's ability to transmit trypanosomes.

  12. Mutualism between co-introduced species facilitates invasion and alters plant community structure

    Science.gov (United States)

    Prior, Kirsten M.; Robinson, Jennifer M.; Meadley Dunphy, Shannon A.; Frederickson, Megan E.

    2015-01-01

    Generalized mutualisms are often predicted to be resilient to changes in partner identity. Variation in mutualism-related traits between native and invasive species however, can exacerbate the spread of invasive species (‘invasional meltdown’) if invasive partners strongly interact. Here we show how invasion by a seed-dispersing ant (Myrmica rubra) promotes recruitment of a co-introduced invasive over native ant-dispersed (myrmecochorous) plants. We created experimental communities of invasive (M. rubra) or native ants (Aphaenogaster rudis) and invasive and native plants and measured seed dispersal and plant recruitment. In our mesocosms, and in laboratory and field trials, M. rubra acted as a superior seed disperser relative to the native ant. By contrast, previous studies have found that invasive ants are often poor seed dispersers compared with native ants. Despite belonging to the same behavioural guild, seed-dispersing ants were not functionally redundant. Instead, native and invasive ants had strongly divergent effects on plant communities: the invasive plant dominated in the presence of the invasive ant and the native plants dominated in the presence of the native ant. Community changes were not due to preferences for coevolved partners: variation in functional traits of linked partners drove differences. Here, we show that strongly interacting introduced mutualists can be major drivers of ecological change. PMID:25540283

  13. Hypothetical Reentry Thermostructural Performance of Space Shuttle Orbiter With Missing or Eroded Thermal Protection Tiles

    Science.gov (United States)

    Ko, William L.; Gong, Leslie; Quinn, Robert D.

    2004-01-01

    This report deals with hypothetical reentry thermostructural performance of the Space Shuttle orbiter with missing or eroded thermal protection system (TPS) tiles. The original STS-5 heating (normal transition at 1100 sec) and the modified STS-5 heating (premature transition at 800 sec) were used as reentry heat inputs. The TPS missing or eroded site is assumed to be located at the center or corner (spar-rib juncture) of the lower surface of wing midspan bay 3. For cases of missing TPS tiles, under the original STS-5 heating, the orbiter can afford to lose only one TPS tile at the center or two TPS tiles at the corner (spar-rib juncture) of the lower surface of wing midspan bay 3. Under modified STS-5 heating, the orbiter cannot afford to lose even one TPS tile at the center or at the corner of the lower surface of wing midspan bay 3. For cases of eroded TPS tiles, the aluminum skin temperature rises relatively slowly with the decreasing thickness of the eroded central or corner TPS tile until most of the TPS tile is eroded away, and then increases exponentially toward the missing tile case.

  14. 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.

  15. 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.

  16. 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.

  17. 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

    -40 cm and 40-60 cm) horizons of the eroded Haplic Luvisol and Ap (0-20 cm) and CBkg (20-40 cm) horizon of the Haplic Regosol. Leaching experiments were performed on intact soil columns (20 cm diameter, 20 cm height) and carried out during unsaturated conditions with a suction applied at the lower...... the finding of a substantially lower leaching of particles from all Regosol horizons, we assume a lower transport of particulate C from the Haplic Regosol than from the eroded Haplic Luvisol. Results suggest that soil erosion not only affected the pedological structure and physical soil properties but also...

  18. Scintigraphic demonstration of acute gastrointestinal bleeding caused by gallbladder carcinoma eroding the colon

    Energy Technology Data Exchange (ETDEWEB)

    Czerniak, A.; Zwas, S.T.; Rabau, M.Y.; Avigad, I.; Borag, B.; Wolfstein, I.

    1985-08-01

    Massive lower gastrointestinal (GI) bleeding caused by gallbladder carcinoma eroding into the colonic wall was demonstrated accurately by Tc-99m RBCs. In addition, retrograde bleeding into the gallbladder was also identified while arteriography did not show contrast extravasation. This case supports the use of Tc-99m RBCs over Tc-99m sulfur colloid for more accurate localization of lower GI bleeding.

  19. Improving and Applying the Measurement of Erodibility: Examining and Calibrating Rock Mass Indices

    Science.gov (United States)

    Rodriguez, R. S.; Spotila, J. A.

    2011-12-01

    The Rock Mass Strength index (Selby, 1980) has become a standard test in geomorphology to quantify rock erodibility. Yet, the index combines a mixture of quantitative and qualitative parameters, yielding classification disparities arising from subjective user interpretations and producing final ratings that are effectively only comparable within a single researcher's dataset. Other methods, such as the Rock Quality Designation (Deere and Deere, 1988) and the Slope Mass Rating system (Bieniawski, 1989; Romana, 1995) employ some additional quantitative methods, but do not eliminate variability in user interpretation. Still, the idea of quantifying erodibility in an easily-applied field method holds great potential for furthering the understanding of large-scale landscape evolution. Therefore, we are applying several published and unpublished erodibility indices across a suite of rock types, varying the relative weights of index parameters and calculating ratings based on various potential interpretations of the index guidelines. To evaluate these results, we regress the iterations against the mean topographic slopes, allowing us to determine which index and weighting scheme is ideal overall. Results thus far have shown discrepancies between rating and slope in rocks that are more susceptible to chemical weathering (a parameter not typically included in erodibility indices). We are therefore examining the addition of chemical composition as an index parameter, or the possibility of creating weighting schema tailored to specific rock types and erosional environments. Preliminary results also suggest that beyond a threshold fracture density, high compressive rock strength is rendered moot, requiring further modification to existing indices.

  20. 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.

  1. Geospatial approach in mapping soil erodibility using CartoDEM–A ...

    Indian Academy of Sciences (India)

    Geospatial approach in mapping soil erodibility using CartoDEM – A case study in hilly watershed of Lower Himalayan Range. Suresh Kumar Surya Gupta ... The present study was attempted to generate soil erodibilty map using terrain indices derived from DTM and surface soil sample data. Soil variability in the hilly ...

  2. Submandibular gland megalith eroding the floor of the mouth: a case report.

    Science.gov (United States)

    Singh, Sourav; Singh, Smita

    2013-12-01

    Sialolithiasis is the most common pathologic condition affecting the salivary glands. However, large sialoliths (megaliths) are considered rare. The submandibular glands are more susceptible to stone formation than are the other salivary glands. We describe the case of a 55-year-old man with an unusually large sialolith that had eroded the floor of the mouth.

  3. 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

  4. Sediment transport capacity of concentrated flows on steep loessial slope with erodible beds.

    Science.gov (United States)

    Xiao, Hai; Liu, Gang; Liu, Puling; Zheng, Fenli; Zhang, Jiaqiong; Hu, Feinan

    2017-05-24

    Previous research on sediment transport capacity has been inadequate and incomplete in describing the detachment and transport process of concentrated flows on slope farmlands during rill development. An indoor concentrated flow scouring experiment was carried out on steep loessial soil slope with erodible bed to investigate the sediment transport capacity under different flow rates and slope gradients. The results indicated that the sediment transport capacity increases with increasing flow rate and slope gradient, and these relationships can be described by power functions and exponential functions, respectively. Multivariate, nonlinear regression analysis showed that sediment transport capacity was more sensitive to slope gradient than to flow rate, and it was more sensitive to unit discharge per unit width than to slope gradient for sediment transport capacity in this study. When similar soil was used, the results were similar to those of previous research conducted under both erodible and non-erodible bed conditions. However, the equation derived from previous research under non-erodible bed conditions with for river bed sand tends to overestimate sediment transport capacity in our experiment.

  5. Geospatial approach in mapping soil erodibility using CartoDEM – A ...

    Indian Academy of Sciences (India)

    Indian Institute of Remote Sensing, Indian Space Research Organization, 4 Kalidas Road,. Dehradun 248 001, India. ∗. Corresponding author. e-mail: suresh kumar@iirs.gov.in. Soil erodibility is one of the most important factors used in spatial soil erosion risk assessment. Soil information derived from soil map is used to ...

  6. [Effects of biological soil crust on soil erodibility in Hilly Loess Plateau region of Northwest China].

    Science.gov (United States)

    Gao, Li-Qian; Zhao, Yun-Ge; Qin, Ning-Qiang; Zhang, Guo-Xiu

    2013-01-01

    Based on the analysis of the effects of biological soil crust (biocrust) in re-vegetated grasslands on soil physical and chemical properties, and by using EPIC estimation model in combining with simulated rainfall trials, this paper studied the effects of biocrust with different biomass and different soil texture on the soil erodibility (K value) in Hilly Loess Plateau Region of Northwest China in different seasons. The results showed biocrust could significantly decrease soil erodibility, with the K value of biocrust soil decreased by about 17%, compared with subsoil. The soil erodibility decreased with the increasing biomass of biocrust. The K value of moss crust soil decreased by 21%, compared with cyanobacteria crust soil. The erodibiliy of biocrust soil differed with different seasons, being significantly higher in rainy season than before or after the rainy season due to the differences in the biological activity of the biocrust organisms. The erodibilty of biocrust soil with different texture also varied significantly, with the K value in the order of sandy loam soil > silt soil > sandy soil. The measurement under simulated rainfall showed that the development of biocrust could decrease the erodibility of biocrust soil by about 90%, compared with that of the subsoil (5-10 cm).

  7. 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

    ). The erodibility of the sediment showed strong temporal variation with high erosion thresholds in spring and late summer and significantly lower thresholds during the rest of the study period. The erosion thresholds were strongly dependent on the contents of chlorophyll a (chl a) and colloidal carbohydrates, both...

  8. Assessment of Soil erodibility Indices and Soil wash in a miniature ...

    African Journals Online (AJOL)

    Soil textural grades and organic matter content were determined in the laboratory by the hydrometer and Walkely-Black methods respectively. Rates of ground lowering were computed from exposed parts of the pins installed in the field after the 2010 rainy season, while erodibility indices were determined from textural ...

  9. Physiological host range of a mutualistic pair: Fergusonina turneri and its obligate nematode Fergusobia quinquenerviae, potential biological control agents of Melaleuca quinquenervia

    Science.gov (United States)

    In Australia, galls develop on Melaleuca quinquenervia (Cav.) S.T. Blake (Myrtales: Myrtaceae) as a result of the mutualistic association between the fly Fergusonina turneri Taylor (Diptera: Fergusoninidae) and its obligate nematode Fergusobia quinquenerviae Davies & Giblin-Davis (Tylenchida: Sphaer...

  10. Investigating the Effect of Compaction Characteristics on the Erodibility of Cohesive Soils Using the JET Method

    Science.gov (United States)

    Asghari Tabrizi, A.; LaRocque, L. A.; Chaudhry, M.; Imran, J.

    2013-12-01

    Several flood disasters occur every year all over the world, mostly due to levee and dam failure which result in human fatalities as well as devastating economic damages. To model and predict earthen embankment failures for the preparation of emergency action plans and risk assessments, the soil erodibility by flowing water is an essential parameter. The determination of erodibility becomes even more complicated for cohesive soils because of the large number of parameters controlling their erosion behavior (e.g. clay content, plasticity, compaction effort, compaction water content) and the difficulty of estimating these parameters. In this study the effect of the compaction energy and compaction water content on the erodibility of a sandy loam soil was assessed. Soil samples were prepared in a standard diameter compaction mold, 101.6 mm, for three levels of compaction effort and water content (i.e. low, medium, and high) with two replications for each case (18 tests total) and examined using the jet erosion test (JET). Observations from qualitative and statistical analyses of the data are: 1) a wide range of erodibility, from very erodible to very resistant, was produced by changes in the compaction characteristics; 2) for a given compaction energy, the erosion resistance based on the detachment rate coefficient kd tends to become minimum near the optimum compaction water content. On the dry side of optimum compaction water content, kd decreases with steep gradients by increasing the water content, while it increases with a flatter gradient on the wet side; 3) At a given water content, the soil erosion resistance increases with compaction efforts; 4) compaction water content influences soil erosibility more than compaction energy, especially on the dry side of the optimum compaction water content; and 5) for a given compaction effort, the critical shear stress increases with water content up to an optimum water content and then it decreases which is in consistent

  11. Uncharismatic Invasives

    Directory of Open Access Journals (Sweden)

    Clark, Jonathan L.

    2015-05-01

    Full Text Available Although philosophers have examined the ethics of invasive species management, there has been little research approaching this topic from a descriptive, ethnographic perspective. In this article I examine how invasive species managers think about the moral status of the animals they seek to manage. I do so through a case study of Oregon’s efforts to manage the invasive species that are rafting across the Pacific attached to tsunami debris in the wake of the Japanese tsunami of 2011. Focusing on the state’s response to a dock that washed ashore on Agate Beach with various marine invertebrates attached to it, I argue that these animals’ position on two intersecting scales of moral worth—the sociozoologic scale and the phylogenetic scale—rendered them unworthy of moral consideration.

  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. 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.

  14. 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

  15. Large-eddy simulation of the flow over a hydrokinetic turbine mounted on an erodible bed

    Science.gov (United States)

    Yang, Xiaolei; Khosronejad, Ali; Sotiropoulos, Fotis

    2013-11-01

    Marine and hydrokinetic (MHK) energy comprises an important source of clean and renewable energy. The beds of natural waterways are usually erodible. The hydrokinetic turbines affect the sediment transport, which, on the other hand, also influences the performance of hydrokinetic turbines. A powerful computational framework for simulating marine and hydrokinetic (MHK) turbine arrays mounted in complex river bathymetry with sediment transport has been developed and validated by our group. In this work we apply this method to simulate the turbulent flow over a hydrokinetic turbine mounted in an open channel with erodible bed. Preliminary results show qualitatively good agreement with the experiment. Detailed comparison with measurements and analysis of the simulation results will be presented in the conference. This work was supported by the University of Minnesota Initiative for Renewable Energy and the Environment IREE (grant no RO-0004-12). Computational resources were provided by the University of Minnesota Supercomputing Institute.

  16. Tracing peatland geomorphology: sediment and contaminant movements in eroding and restored systems

    Science.gov (United States)

    Shuttleworth, Emma; Evans, Martin; Hutchinson, Simon; Rothwell, James

    2015-04-01

    Peatlands are an important store of soil carbon, play a vital role in global carbon cycling, and can also act as sinks of atmospherically deposited heavy metals. However, large areas of blanket peat are significantly degraded and actively eroding as a direct result of anthropogenic pressures, which negatively impacts carbon and pollutant storage. The restoration of eroding UK peatlands is a major conservation concern, and over the last decade measures have been taken to control erosion and restore large areas of degraded peat. In severely eroded peatlands, topography is highly variable, and an appreciation of geomorphological form and process is key in understanding the controls on peatland function, and in mitigating the negative impacts of peatland erosion. The blanket peats of the Peak District, Southern Pennines, UK embody many problems and pressures faced by peatlands globally, and are amongst the most heavily eroded and contaminated in the world. The near-surface layer of the peat is contaminated by high concentrations of anthropogenically derived, atmospherically deposited heavy metals which are released into the fluvial system as a consequence of widespread erosion. Whilst not desirable, this legacy of lead pollution and its release offer a unique opportunity to trace peatland sediment movements and thus investigate the controls on sediment and contaminant mobility. A suite of established field, analytical and modelling techniques have been modified and adapted for use in peatland environments and these have been successfully employed in combination to address issues of sediment and contaminant release at a range of scales, including: (i) the development of field portable XRF to assess in situ lead concentrations in wet organic sediments; (ii) adaptation of time integrated mass flux samplers to explore spatial and temporal sediment dynamics in peatland streams; and (iii) the application of sediment source fingerprinting and numerical mixing models to

  17. Mangrove Rehabilitation on Highly Eroded Coastal Shorelines at Samut Sakhon, Thailand

    Directory of Open Access Journals (Sweden)

    Matsui Naohiro

    2012-01-01

    Full Text Available The study site is currently retreating at a rate of 20 m y−1 due to severe coastal erosion and found to be highly polluted as revealed from the water, sediment and biological analysis. In an attempt to prevent coastal erosion, 14,000 Rhizophora mucronata (RM trees were planted across a heavily eroded shoreline at Samut Sakhon, Thailand. The survival rate of RM was high at the landward area and decreased at the offshore area. The most landward plot showed the highest survival rate when measured 4 years after planting (63.5%, while only 26.7% of trees survived at the most offshore plot. NPK and coconut fiber were shown to be significantly effective to enhance initial tree growths in heavily eroded area.

  18. 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

    Minimizing soil erosion is essential for maintaining proper soil quality and thus preserving soil productivity. The erodibility of a soil is closely linked to its structural stability as well as its infiltrability. This study focuses on testing the effect of two different soil amendments on soil...... 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...

  19. Abrasion of eroded and sound enamel by a dentifrice containing diamond abrasive particles

    Science.gov (United States)

    Wegehaupt, Florian J.; Hoegger, Vanessa G. M.; Attin, Thomas

    2017-07-24

    Eroded enamel is more susceptible to abrasive wear than sound enamel. New toothpastes utilizing diamond particles as abrasives have been developed. The present study investigated the abrasive wear of eroded enamel by three commercially available toothpastes (one containing diamond particles) and compared it to the respective wear of sound enamel caused by these toothpastes. Seventy-two bovine enamel samples were randomly allocated to six groups (S1–S3 and E1–E3; n=12). Samples were submitted to an abrasive (S1–S3) or erosion plus abrasion (E1–E3) cycling. Per cycle, all samples were brushed (abrasion; 20 brushing stokes) with the following toothpastes: S1/E1: Signal WHITE SYSTEM, S2/E2: elmex KARIESSCHUTZ and S3-E3: Candida WHITE DIAMOND (diamond particles). Groups E1–E3 were additionally eroded with HCl (pH 3.0) for 2 min before each brushing procedure. After 30, 60 and 90 cycles enamel wear was measured by surface profilometry. Within the same toothpaste and same number of cycles, enamel wear due to erosion plus abrasion was significantly higher than due to mere abrasion. After 30, 60 and 90 cycles, no significant difference in the wear in groups S1 and S2 was observed while the wear in group E1 was significantly (pwear in group S3 was about 5 times higher than that in group S2, while wear in group E3 was about 1.3 times higher than that in group E2. As compared to the other two investigated toothpastes, the dentifrice containing diamond particles caused slightly higher abrasive wear of eroded enamel and distinctly higher wear of sound enamel compared to the conventional toothpastes under investigation.

  20. 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

  1. A conservative treatment approach using direct composite resins for anterior teeth eroded by lemon sucking.

    Science.gov (United States)

    Passos, Vanara Florencio; de Souza, Andre Mattos Brito; Rodrigues, Lidiany Karla Azevedo; Bombonatti, Juliana Campos Fraga Soares; Santiago, Sergio Lima

    2013-08-01

    An excessively acidic diet results in the progressive deterioration of dental health, with functional, esthetic, and biological consequences. Previously, rehabilitation required placing numerous full crowns and root canal treatments; however, with improved adhesive techniques, a more conservative approach may be utilized to preserve tooth structure. This article describes 2 cases that utilized conservative dental treatments (involving direct composite resins with minimal preparation of the tooth structure) to treat eroded dentition induced by lemon sucking.

  2. 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.

  3. Abrasive wear on eroded root dentine after different periods of exposure to saliva in situ.

    Science.gov (United States)

    Hara, Anderson Takeo; Turssi, Cecilia Pedroso; Teixeira, Erica Capelletto Nogueira; Serra, Mônica Campos; Cury, Jaime Aparecido

    2003-10-01

    The effect of salivary exposure time on the abrasive wear of acid-eroded dentine was evaluated in situ. One-hundred and twenty bovine root dentine slabs were randomly assigned into six groups (A-F) and placed in intraoral palatal devices, which were worn by 10 volunteers for 4 d. On the first day, no erosive/abrasive procedures were carried out. On the following 3 d, erosive challenges were performed extraorally, two times per day, by immersing the device for 90 s in a soft drink. Subsequently, the group A specimens were immediately brushed (40 strokes), and the others were brushed after the following times: B, 20 min; C, 40 min; and D, 60 min. Group E specimens were only acid-eroded and those of group F were only brushed. Dentine wear was measured with a profilometer. anova and Dunnett's test showed that groups A-D did not differ statistically from the control group E but differed from the control group F. The lowest mean value was found for group F. Regression analysis was unable to show salivary effect on dentine wear reduction. The data suggest that the exposure time of saliva of up to 60 min has no effect on reducing the eroded dentine wear by toothbrushing.

  4. Mineralization rate of eroded organic C in Andosols of the Canary Islands.

    Science.gov (United States)

    Mora, Juan Luis; Guerra, José Asterio; Armas, Cecilia María; Rodríguez-Rodríguez, Antonio; Arbelo, Carmen Dolores; Notario, Jesús Santiago

    2007-05-25

    The aim of this paper is to determine the biological dynamism of the organic C forms bonded to soil particles mobilized by water erosion in Andosols of the Canary Islands, to evaluate their susceptibility towards mineralization processes and the role of sediments as sources or sinks of atmospheric CO(2) in these soils. The study was carried out in Tenerife (Canary Islands) on three 200 m(2) experimental plots of the RESEL Programme on silic Andosols under forest, 3 years after being subjected to clear-cutting. Eroded sediments were collected for analysis from five significant winter rainfall episodes. For each event, samples of surface (0-5 cm) soil in situ were also collected. CO(2)-C was measured by incubation in all the samples, as well as microbial biomass-linked C. The results obtained show an enrichment in the eroded sediments of microbial biomass (7.5+/-1.6 g kg(-1) vs. 3.8+/-1.5 g kg(-1)) and of potentially mineralizable C (1419 mg CO(2)-C kg(-1) vs. 386 mg CO(2)-C kg(-1)). In addition, there was twice as much mineralization of C compounds in eroded sediments as in the soil surface horizon.

  5. 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 % .

  6. Practical application of methanol-mediated mutualistic symbiosis between Methylobacterium species and a roof greening moss, Racomitrium japonicum.

    Science.gov (United States)

    Tani, Akio; Takai, Yuichiro; Suzukawa, Ikko; Akita, Motomu; Murase, Haruhiko; Kimbara, Kazuhide

    2012-01-01

    Bryophytes, or mosses, are considered the most maintenance-free materials for roof greening. Racomitrium species are most often used due to their high tolerance to desiccation. Because they grow slowly, a technology for forcing their growth is desired. We succeeded in the efficient production of R. japonicum in liquid culture. The structure of the microbial community is crucial to stabilize the culture. A culture-independent technique revealed that the cultures contain methylotrophic bacteria. Using yeast cells that fluoresce in the presence of methanol, methanol emission from the moss was confirmed, suggesting that it is an important carbon and energy source for the bacteria. We isolated Methylobacterium species from the liquid culture and studied their characteristics. The isolates were able to strongly promote the growth of some mosses including R. japonicum and seed plants, but the plant-microbe combination was important, since growth promotion was not uniform across species. One of the isolates, strain 22A, was cultivated with R. japonicum in liquid culture and in a field experiment, resulting in strong growth promotion. Mutualistic symbiosis can thus be utilized for industrial moss production.

  7. Practical application of methanol-mediated mutualistic symbiosis between Methylobacterium species and a roof greening moss, Racomitrium japonicum.

    Directory of Open Access Journals (Sweden)

    Akio Tani

    Full Text Available Bryophytes, or mosses, are considered the most maintenance-free materials for roof greening. Racomitrium species are most often used due to their high tolerance to desiccation. Because they grow slowly, a technology for forcing their growth is desired. We succeeded in the efficient production of R. japonicum in liquid culture. The structure of the microbial community is crucial to stabilize the culture. A culture-independent technique revealed that the cultures contain methylotrophic bacteria. Using yeast cells that fluoresce in the presence of methanol, methanol emission from the moss was confirmed, suggesting that it is an important carbon and energy source for the bacteria. We isolated Methylobacterium species from the liquid culture and studied their characteristics. The isolates were able to strongly promote the growth of some mosses including R. japonicum and seed plants, but the plant-microbe combination was important, since growth promotion was not uniform across species. One of the isolates, strain 22A, was cultivated with R. japonicum in liquid culture and in a field experiment, resulting in strong growth promotion. Mutualistic symbiosis can thus be utilized for industrial moss production.

  8. Specificity in chemical profiles of workers, brood and mutualistic fungi in Atta, Acromyrmex, and Sericomyrmex fungus-growing ants.

    Science.gov (United States)

    Richard, Freddie-Jeanne; Poulsen, Michael; Drijfhout, Falko; Jones, Graeme; Boomsma, Jacobus J

    2007-12-01

    Neotropical attine ants live in obligatory symbiosis with a fungus that they grow for food on a substrate of primarily plant material harvested by workers. Nestmate recognition is likely based on chemical cues as in most other social insects, but recent studies have indicated that both the ants and their mutualistic fungi may contribute to the recognition templates. To investigate the within-colony variation in chemical profiles, we extracted and identified compounds from the cuticle of workers, the postpharyngeal gland of workers, ant pupae and larvae, and the fungal symbiont of three species of higher attine ants: Atta colombica, Acromyrmex echinatior, and Sericomyrmex amabilis. The relative proportions of identified compounds were compared and represented 11 classes: n-alkanes, alkenes, branched methylalkanes, branched dimethylalkanes, trimethylalkanes, branched alkenes, aldehydes, alcohols, acetates, acids, and esters. The chemical profiles in all three species are likely to be sufficiently different to allow discrimination at the species and colony level and sufficiently similar within colonies to generate a relatively constant colony-specific chemical gestalt. The relative likelihood of individual compounds being derived from the ants, the ant brood, or the fungal symbiont are discussed. We hypothesize that hydrocarbons are particularly important as recognition cues because they appear to simultaneously allow the assessment of developmental stages and the identification of symbiont, colony, and species.

  9. Sustained exposure to abscisic acid enhances the colonization potential of the mutualist fungus Piriformospora indica on Arabidopsis thaliana roots.

    Science.gov (United States)

    Peskan-Berghöfer, Tatjana; Vilches-Barro, Amaya; Müller, Teresa M; Glawischnig, Erich; Reichelt, Michael; Gershenzon, Jonathan; Rausch, Thomas

    2015-11-01

    Root colonization by the beneficial fungus Piriformospora indica is controlled by plant innate immunity, but factors that channel this interaction into a mutualistic relationship are not known. We have explored the impact of abscisic acid (ABA) and osmotic stress on the P. indica interaction with Arabidopsis thaliana. The activation of plant innate immunity in roots was determined by measuring the concentration of the phytoalexin camalexin and expression of transcription factors regulating the biosynthesis of tryptophan-related defence metabolites. Furthermore, the impact of the fungus on the content of ABA, salicylic acid, jasmonic acid (JA) and JA-related metabolites was examined. We demonstrated that treatment with exogenous ABA or the ABA analogue pyrabactin increased fungal colonization efficiency without impairment of plant fitness. Concomitantly, ABA-deficient mutants of A. thaliana (aba1-6 and aba2-1) were less colonized, while plants exposed to moderate stress were more colonized than corresponding controls. Sustained exposure to ABA attenuated expression of transcription factors MYB51, MYB122 and WRKY33 in roots upon P. indica challenge or chitin treatment, and prevented an increase in camalexin content. The results indicate that ABA can strengthen the interaction with P. indica as a consequence of its impact on plant innate immunity. Consequently, ABA will be relevant for the establishment and outcome of the symbiosis under stress conditions. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  10. Host pollination mode and mutualist pollinator presence: net effect of internally ovipositing parasite in the fig-wasp mutualism

    Science.gov (United States)

    Zhang, Fengping; Peng, Yanqiong; Compton, Stephen G.; Zhao, Yi; Yang, Darong

    2009-04-01

    The Ficus-their specific pollinating fig wasps (Chalcidoidea, Agaonidae) interaction presents a striking example of mutualism. Figs also shelter numerous non-pollinating fig wasps (NPFW) that exploit the fig-pollinator mutualism. Only a few NPFW species can enter figs to oviposit, they do not belong to the pollinating lineage Agaonidae. The internally ovipositing non-agaonid fig wasps can efficiently pollinate the Ficus species that were passively pollinated. However, there is no study to focus on the net effect of these internally ovipositing non-agaonid wasps in actively pollinated Ficus species. By collecting the data of fig wasp community and conducting controlled experiments, our results showed that internally ovipositing Diaziella bizarrea cannot effectively pollinate Ficus glaberrima, an actively pollinated monoecious fig tree. Furthermore, D. bizarrea failed to reproduce if they were introduced into figs without Eupristina sp., the regular pollinator, as all the figs aborted. Furthermore, although D. bizarrea had no effect on seed production in shared figs, it significantly reduced the number of Eupristina sp. progeny emerging from them. Thus, our experimental evidence shows that reproduction in Diaziella depends on the presence of agaonid pollinators, and whether internally ovipositing parasites can act as pollinators depends on the host fig’s pollination mode (active or passive). Overall, this study and others suggest a relatively limited mutualistic role for internally ovipositing fig wasps from non-pollinator (non-Agaonidae) lineages.

  11. Chemical transfers along slowly eroding catenas developed on granitic cratons in southern Africa

    Science.gov (United States)

    Khomo, Lesego; Bern, Carleton R.; Hartshorn, Anthony S.; Rogers, Kevin H.; Chadwick, Oliver A.

    2013-01-01

    A catena is a series of distinct but co-evolving soils arrayed along a slope. On low-slope, slowly eroding catenas the redistribution of mass occurs predominantly as plasma, the dissolved and suspended constituents in soil water. We applied mass balance methods to track how redistribution via plasma contributed to physical and geochemical differentiation of nine slowly eroding (~ 5 mm ky− 1) granitic catenas. The catenas were arrayed in a 3 × 3 climate by relief matrix and located in Kruger National Park, South Africa. Most of the catenas contained at least one illuviated soil profile that had undergone more volumetric expansion and less mass loss, and these soils were located in the lower halves of the slopes. By comparison, the majority of slope positions were eluviated. Soils from the wetter climates (550 and 730 mm precipitation yr− 1) generally had undergone greater collapse and lost more mass, while soils in the drier climate (470 mm yr− 1) had undergone expansion and lost less mass. Effects of differences in catena relief were less clear. Within each climate zone, soil horizon mass loss and strain were correlated, as were losses of most major elements, illustrating the predominant influence of primary mineral weathering. Nevertheless, mass loss and volumetric collapse did not become extreme because of the skeleton of resistant primary mineral grains inherited from the granite. Colloidal clay redistribution, as traced by the ratio of Ti to Zr in soil, suggested clay losses via suspension from catena eluvial zones. Thus illuviation of colloidal clays into downslope soils may be crucial to catena development by restricting subsurface flow there. Our analysis provides quantitative support for the conceptual understanding of catenas in cratonic landscapes and provides an endmember reference point in understanding the development of slowly eroding soil landscapes.

  12. Landslides as weathering reactors; links between physical erosion and weathering in rapidly eroding mountain belts

    Science.gov (United States)

    Emberson, R.; Hovius, N.; Galy, A.

    2014-12-01

    The link between physical erosion and chemical weathering is generally modelled with a surface-blanketing weathering zone, where the supply of fresh minerals is tied to the average rate of denudation. In very fast eroding environments, however, sediment production is dominated by landsliding, which acts in a stochastic fashion across the landscape, contrasting strongly with more uniform denudation models. If physical erosion is a driver of weathering at the highest erosion rates, then an alternative weathering model is required. Here we show that landslides can be effective 'weathering reactors'. Previous work modelling the effect of landslides on chemical weathering (Gabet 2007) considered the fresh bedrock surfaces exposed in landslide scars. However, fracturing during the landslide motion generates fresh surfaces, the total surface area of which exceeds that of the exposed scar by many orders of magnitude. Moreover, landslides introduce concavity into hillslopes, which acts to catch precipitation. This is funnelled into a deposit of highly fragmented rock mass with large reactive surface area and limited hydraulic conductivity (Lo et al. 2007). This allows percolating water reaction time for chemical weathering; any admixture of macerated organic debris could yield organic acid to further accelerate weathering. In the South island of New Zealand, seepage from recent landslide deposits has systematically high solute concentrations, far outstripping concentration in runoff from locations where soils are present. River total dissolved load in the western Southern Alps is highly correlated with the rate of recent (<35yrs) landsliding, suggesting that landslides are the dominant locus of weathering in this rapidly eroding landscape. A tight link between landsliding and weathering implies that localized weathering migrates through the landscape with physical erosion; this contrasts with persistent and ubiquitous weathering associated with soil production. Solute

  13. 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

  14. The DNA damage response at eroded telomeres and tethering to the nuclear pore complex

    DEFF Research Database (Denmark)

    Khadaroo, Basheer; Teixeira, M Teresa; Luciano, Pierre

    2009-01-01

    to induce the recruitment of checkpoint and recombination proteins. Notably, a DNA damage response at eroded telomeres starts many generations before senescence and is characterized by the recruitment of Cdc13 (cell division cycle 13), replication protein A, DNA damage checkpoint proteins and the DNA repair......The ends of linear eukaryotic chromosomes are protected by telomeres, which serve to ensure proper chromosome replication and to prevent spurious recombination at chromosome ends. In this study, we show by single cell analysis that in the absence of telomerase, a single short telomere is sufficient...

  15. Fractal dimension of soil aggregates as an index of soil erodibility

    Science.gov (United States)

    Ahmadi, Abbas; Neyshabouri, Mohammad-Reza; Rouhipour, Hassan; Asadi, Hossein

    2011-04-01

    SummaryAggregate stability is an influential factor governing soil erodibility. The fractal dimension of soil aggregates has been related to their size distributions and stabilities. Several fractal models have been proposed for estimating fractal dimension of soil aggregates. This study was conducted to investigate how closely the soil interrill erodibility factor in WEPP model can be correlated to and predicted from soil aggregate size distribution or from their fractal dimensions. Samples from 36 soil series with contrasting properties were collected from northwest of Iran. The fractal dimensions of soil aggregates were calculated from Rieu and Sposito ( D n), Tyler and Wheatcraft ( D mT), and Young and Crawford ( D mY) models using aggregate size distribution (ASD) data. A rainfall simulator with drainable tilting flume (1 × 0.5 m) at slope of 9% was employed and total interrill erosion ( TIE), total splashed soil ( TS) and interrill erodibility factor ( K i) were calculated for 20, 37, and 47 mm h -1 rainfall intensities. Results showed that both D n and D mT estimated from aggregate wet-sieving data characterized ASD of the examined soils and significantly ( p < 0.01) correlated to TS, TIE and K i. Values of D n and D mT estimated from dry-sieving data only correlated to TS but not to TIE and K i. Using air-dried aggregates of 4.75-8 mm size range, instead of aggregates <4.75 mm, in wet-sieving was better for estimating D n as an index for the predication of TIE, TS and K i. Correction of ASD for the particle fraction greater than lower sieve mesh size in each size class decreased the correlation coefficient between TIE, TS or K i and D n or D mT. The values of D mY were not correlated to TS, TIE and K i. The correlation coefficient TIE and K i with D n and D mT derived from wet-sieving data, were higher than those with wet-aggregate stability (WAS), mean weight diameter (MWD) and geometric mean diameter (GMD), implying that D n and D mT may be better

  16. Terrestrial photography as method to identify sediment sources in eroding rills

    Science.gov (United States)

    Wirtz, Stefan; Remke, Alexander; Wengel, René; Seeger, Manuel; Ries, Johannes B.

    2013-04-01

    One weak point in available studies on erosion processes in eroding rills is the lack of information about the real source of transported sediment. So far, such sources can only be identified by observation during the event or the experiment. Quantification is not possible by this way, additionally only large and clear visible changes are considered. In this study we present a method to quantify even small topographical changes in eroding rills during experiments or real rainfall events. We tested the suitability of DEMs created from terrestrial stereo photographies before and after application of artificial runoff to quantify eroded, transported and sedimented material in the rill. In 1 m intervals, pairs of photos are taken along the tested rills. The setup ensures that both cameras are moved with a constant parallax. The height of only about 1 m above ground level ensures that even low quantities of moved material can be identified. Based on technical data of the camera and the shot level, the theoretical accuracy of the images is below 1 mm horizontal ground resolution. The camera carrier bases on a rotating tower crane which has been developed from a customary survey tripod. The stereo images are combined with free-hand photographies from different angles of view to reach overhangs in rill sidewalls and ensure a fully 3D representation of the rill. In the analyses of the photographies 2 different kinds of software are used: The standard software Leica Photogrammetry Suite requires stereo images and ground control points whereas the open source software package is able to handle either stereo images as well as free-hand photographies. Ground control points are not needed, the software identifies point clusters which are to find in overlapping images. Using these feature-points, spatial marks are positioned which are used to match and rectify the single images to get an apposite panorama. By this way images from very different angles of view can be combined. The

  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. 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.

  19. 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.

  20. Remote Sensing Analysis of a Rapidly Eroding Sea Cliff at Point Grey, British Columbia

    Science.gov (United States)

    Westin, A. M.; Francioni, M.; Kremsater, R.; Stead, D.; Clague, J. J.

    2015-12-01

    A range of remote sensing tools can be used to document hazardous and sensitive environments. Presented at this time are the first results of an ongoing study of a rapidly eroding, steep sea cliff in Vancouver, British Columbia. The sea cliff is formed in a 70-m-thick sequence of outwash sands and silts (Quadra Sand) deposited during the early part of the last glaciation, known locally as the Fraser Glaciation. The sea cliff is unstable and retreating due to wave attack, groundwater seepage, and shallow-seated landslides. If no measures are taken to stem wave erosion, the sea cliff will likely retreat faster with rising seas over the remainder of this century. The beach below the cliff is a popular recreational location, thus a hard engineering solution to the erosion problem might be unacceptable to Vancouver residents. We have used conventional photogrammetry, structures from motion, thermal imaging, and terrestrial full waveform laser scanning to provide base-line spatial data for the most rapidly eroding section of the cliff. Here, we present some of our results and discuss the challenges that we faced in characterizing this large soil slope.

  1. 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.

  2. 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 laser did not affect roughness of dental 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.

  3. Mutualists and antagonists drive among-population variation in selection and evolution of floral display in a perennial herb.

    Science.gov (United States)

    Agren, Jon; Hellström, Frida; Toräng, Per; Ehrlén, Johan

    2013-11-05

    Spatial variation in the direction of selection drives the evolution of adaptive differentiation. However, few experimental studies have examined the relative importance of different environmental factors for variation in selection and evolutionary trajectories in natural populations. Here, we combine 8 y of observational data and field experiments to assess the relative importance of mutualistic and antagonistic interactions for spatial variation in selection and short-term evolution of a genetically based floral display dimorphism in the short-lived perennial herb Primula farinosa. Natural populations of this species include two floral morphs: long-scaped plants that present their flowers well above the ground and short-scaped plants with flowers positioned close to the ground. The direction and magnitude of selection on scape morph varied among populations, and so did the frequency of the short morph (median 19%, range 0-100%; n = 69 populations). A field experiment replicated at four sites demonstrated that variation in the strength of interactions with grazers and pollinators were responsible for among-population differences in relative fitness of the two morphs. Selection exerted by grazers favored the short-scaped morph, whereas pollinator-mediated selection favored the long-scaped morph. Moreover, variation in selection among natural populations was associated with differences in morph frequency change, and the experimental removal of grazers at nine sites significantly reduced the frequency of the short-scaped morph over 8 y. The results demonstrate that spatial variation in intensity of grazing and pollination produces a selection mosaic, and that changes in biotic interactions can trigger rapid genetic changes in natural plant populations.

  4. 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

  5. Invasive amebiasis.

    Science.gov (United States)

    Grecu, F; Bulgariu, Teodora; Blanaru, Oana; Dragomir, C; Lunca, Claudia; Stratan, I; Manciuc, Carmen; Luca, V

    2006-01-01

    Digestive amoebiasis with his invasive form is an unusual pathology encountered in the temperate zone. This could lead to a life threatening complication: systemic amoebiasis. A 55-year-old male was treated successfully of systemic amoebiasis in a third referral hospital. The diagnosis was established based on epidemiology data and microscopical identification of trophozoites of Entamoeba histolytica. The amoebicidal, antibiotic and supportive treatments was firstly administrated. The clinical picture of intestinal amoebiasis raised from dysenteric syndrome to necrotizing enteritis. The bowel perforation with localized peritonitis was followed by chronic enteric fistula. Amoebic liver abscess, as the most frequent extraintestinal complication, was concomitantly diagnosed and treated. Urinary amoebiasis was considered as complication in the context of systemic dissemination: any other location could become a site of an amoebic abscess. Multidisciplinary approach was the successful key in the management of the patient, including antiparasitic therapy and antibiotic prophylaxis, intensive care and multiple surgical approaches. The diagnosis of digestive amoebiasis and systemic complication may be delayed in nonendemic areas, leading to advanced and complicated stages of the disease. The surgical approach is most efficiently to treat a large liver amoebic abscess and intraperitoneal collections.

  6. 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

  7. Variation of basal EROD activities in ten passerine bird species--relationships with diet and migration status.

    Science.gov (United States)

    Rainio, Miia J; Kanerva, Mirella; Wahlberg, Niklas; Nikinmaa, Mikko; Eeva, Tapio

    2012-01-01

    Inter-specific differences in animal defence mechanisms against toxic substances are currently poorly understood. The ethoxyresorufin-O-deethylase (EROD) enzyme plays an important role in defence against toxic chemicals in a wide variety of animals, and it is an important biomarker for environmental contamination. We compared basal hepatic EROD activity levels among ten passerine species to see if there is inter-specific variation in enzyme activity, especially in relation to their diet and migration status. Migratory insectivores showed higher EROD activity compared to granivores. We hypothesize that the variable invertebrate diet of migratory insectivores contains a wider range of natural toxins than the narrower diet of granivores. This may have affected the evolution of mixed function oxidases (MFO) system and enzyme activities. We further tested whether metabolic rates or relative liver size were associated with the variation in detoxification capacity. We found no association between EROD activity and relative (per mass unit) basal metabolic rate (BMR). Instead, EROD activity and relative liver mass (% of body mass) correlated positively, suggesting that a proportionally large liver also functions efficiently. Our results suggest that granivores and non-migratory birds may be more vulnerable to environmental contaminants than insectivores and migratory birds. The diet and migration status, however, are phylogenetically strongly connected to each other, and their roles cannot be fully separated in our analysis with only ten passerine species.

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

    Directory of Open Access Journals (Sweden)

    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.

  9. Análise da erodibilidade de saprolitos de gnaisse Erodibility analysis of gneiss saprolite

    Directory of Open Access Journals (Sweden)

    F. Morais

    2004-12-01

    Full Text Available As voçorocas são freqüentes em áreas com rochas do embasamento cristalino. A evolução destas feições é sempre fortemente condicionada pelos processos de erosão hídrica subsuperficial, embora os processos superficiais também sejam importantes. Este trabalho objetivou investigar os processos erosivos subsuperficiais atuantes nas voçorocas e compreender que fatores mineralógicos e texturais poderiam influenciar a erodibilidade dos saprolitos. Para tanto, foram realizados ensaios de caracterização e de avaliação da erodibilidade em amostras representativas, sendo o principal destes o ensaio de furo de agulha. Os resultados indicam que a erosão por carreamento não ocorre e que os saprolitos apresentam susceptibilidade variável à erosão por piping, mesmo quando derivados de uma mesma unidade litológica, mas superior à do horizonte B latossólico. Dados preliminares indicam que os saprolitos mais susceptíveis à erosão por piping são os de textura siltosa (determinados em ensaios granulométricos sem defloculante e agitação e pobres em minerais agregadores, como os argilominerais.Gully erosion are very common in areas with gneiss basement rocks. Their development is strongly influenced by subsuperficial processes, although the surface ones are also important. This study aimed to investigate the subsuperficial erosion mechanisms of these gullies and to understand how mineralogy and texture could influence the saprolite erodibility. Some basic trials and erodibility tests were carried out in representative samples, with imphasis to especially the pin-hole test. The results showed that seepage erosion does not occur and that saprolite present variable susceptibility to piping erosion, even if they are in the same geologic unit. The data confirm that soils with Bw horizon (Oxisols are less erodible than any of the tested saprolites. Preliminary data suggest that saprolites with a silty texture (determined without dispersant

  10. Manure and tillage use in remediation of eroded land and impacts on soil chemical properties.

    Science.gov (United States)

    Mikha, Maysoon M; Benjamin, Joseph G; Vigil, Merle F; Poss, David J

    2017-01-01

    Soil loss through wind and water erosion is an ongoing problem in semiarid regions. A thin layer of top soil loss over a hectare of cropland could be corresponding to tons of productive soil loss per hectare. The objectives of this study were to evaluate the influence of beef feedlot manure, tillage and legume grass mixtures on changes in soil quality and nutrient components. The study was initiated in 2006 on an eroded site near Akron, Colorado, on a Norka-Colby very-fine sandy loam (fine-silty, mixed, mesic, Aridic, Argiustolls). Tillage treatments were no-tillage, shallow tillage (sweeps operations with V-blade) and deep tillage (DT; moldboard plow operations). In one set of plots, DT was implemented biannually (DT-2); and in another set the DT was done once at the initiation of the experiment in 2006. Amendments consisted of beef manure and urea (46-0-0), N fertilizer. Both amendments were added at low and high rates. A control treatment, with no fertilizer or manure added, was included with no-tillage and shallow tillage only. Six years of manure addition and tillage significantly altered soil chemical properties compared with fertilizer and grass legume mixtures. Across all the tillage treatments, at the 0-30 cm depth, soil pH from 2006 to 2012, was reduced 1.8 fold with high-manure compared with high-fertilizer treatment. Soil EC, Na, and SAR increased by 2.7 fold while soil P increase by 3.5 fold with high-manure treatment compared with low-manure from 2006 to 2012 across all the tillage treatments at the surface 0-30 cm. Soil organic carbon associated with high-manure was 71% higher than low-manure and 230% higher than high-fertilizer treatments in the 0-60 cm depth. Similar patterns were observed with soil total N. Overall, manure amendments greatly improved the soil nutrient status on this eroded site. However, the legume grass mixtures showed little effect on improving soils chemical properties. The micronutrients supplied by manure improved the soil

  11. 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...... controlling a microfungal parasite of their fungus gardens. Interaction between this bacterium and gland secretion therefore seems unavoidable. We document the typical development of bacterial growth on the cuticle of young major workers, show that growth starts a few days after eclosion, and that the maximal...

  12. Specificity in chemical profiles of workers, brood and mutualistic fungi in Atta, Acromyrmex, and Sericomyrmex fungus-growing ants

    DEFF Research Database (Denmark)

    Richard, Freddie-Jeanne; Poulsen, Michael; Drijfhout, Falko

    2007-01-01

    Neotropical attine ants live in obligatory symbiosis with a fungus that they grow for food on a substrate of primarily plant material harvested by workers. Nestmate recognition is likely based on chemical cues as in most other social insects, but recent studies have indicated that both the ants...... and their mutualistic fungi may contribute to the recognition templates. To investigate the within-colony variation in chemical profiles, we extracted and identified compounds from the cuticle of workers, the postpharyngeal gland of workers, ant pupae and larvae, and the fungal symbiont of three species of higher...

  13. 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

    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...... of eroded SOC takes place on downslope soils within the catchment and in adjacent inland waters, i.e. substantial amounts of SOC are transferred from terrestrial to aquatic ecosystems. However, the net effect on C exchange between soils, atmosphere and inland waters is unknown. We hypothesize...... 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...

  14. Stabilisation of erodible soil by fly ash and blast furnace slag

    Energy Technology Data Exchange (ETDEWEB)

    Indraratna, B.; Salim, W. [Civil Engineering Division, University of Wollongong, N.S.W., Wollongong (Australia)

    2000-07-01

    Residual soils are found on large terrains which are often subjected to considerable erosion. This paper presents a detailed laboratory evaluation of the effect of fly ash and blast furnace slag on two different soils: (a) culluvium (sandy loam) from New South Wales, Australia and (b) erodible dispersive clay from northeast Thailand. Geotechnical tests were conducted to determine the compaction characteristics and the compressive and shear strength properties of the blended and natural soil specimens. The effect of the above mentioned industrial wastes on the rate of erosion and on the associated pH levels is also investigated. Fine grained fly ash is found to be useful as a void filler if used in substantial quantities, whereas selfhardening milled slag is more effective in terms of improving the internal friction angle of the treated soil. 18 refs.

  15. Natural geo-composites for grassing of eroded and degraded lands

    Directory of Open Access Journals (Sweden)

    Kroumov Victor

    2009-01-01

    Full Text Available Original, natural grass geocomposites (sods were developed on the basis of combination from unstuffy, needle-drive textile material, geo-net and soil-manure-peat or peat with grass cover from grass mixtures. The natural grass geocomposites have the next priorities: quickly grassing and reinforcing of eroded and degraded terrains; large uniformity and compactness of grass cove; long exploiting period; grassing of terrains with big slopes where the mechanization is difficult to use; the articles are with low mass, small thickness and high stability; they limit the growing of weed. The natural grass geocomposites are intend for control of soil erosion and reconstruction of natural landshaft. They can to reinforce ditches, grass collectors, side of the road slopes, as well as lay out lawn, parks, stadiums, ski racing tourist's beauty spot, etc.

  16. Climate Change Impact on Paddy Farming in Erode and Tiruchirapalli Districts of Tamil Nadu

    Directory of Open Access Journals (Sweden)

    Sivaraj Paramasivam

    2016-07-01

    Full Text Available Climate change implies both direct and indirect impact on the general well-being of the people in the rural community such as agriculture and allied sectors for their livelihood security.  A study was conducted on the small and marginal paddy farmers of Tamil Nadu. A sample size of 200 paddy farmers was selected from the districts of Erode and Tiruchirappalli, Tamil Nadu. Findings revealed that paddy farmers perceived climate change impacts includes five major components viz. crop nature, pest incidence, disease menace, water crisis and agro climatic status. It was found that farmers were much aware of the variations in rainfall pattern and its distribution followed by variability in temperature and changes in wind speed and direction. Receipt of low rainfall was found to be the most pertinent issue.

  17. Turnover of eroded soil organic carbon after deposition in terrestrial and aquatic environments

    DEFF Research Database (Denmark)

    Kirkels, Frédérique; Cammeraat, Erik; Kalbitz, Karsten

    The fate of eroded soil organic carbon (SOC) after deposition is a large uncertainty in assessing the impact of soil erosion on C budgets. Globally, large amounts of SOC are transported by erosion and a substantial part is transferred into adjacent inland waters, linking terrestrial and aquatic C...... soil properties (e.g. texture, aggregation, etc.), SOC quantity and quality. In a 16-week incubation experiment, SOC turnover was determined for conditions reflecting downslope soils or inland waters. Moreover, we studied the impact of labile C inputs (‘priming’) on SOC stability using 13C labeled...... cellulose. Physical and chemical soil properties and SOC molecular composition were assessed as potential controls on C turnover. SOC deposition in aquatic environments resulted in upto 3.5 times higher C turnover than deposition on downslope soils. Labile C inputs enlarged total CO2 emissions...

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

    Directory of Open Access Journals (Sweden)

    P. N. Palanisamy

    2007-01-01

    Full Text Available 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, bicarbonate alkalinity, total alkalinity, total dissolved solids, total solids, total suspended solids, calcium, magnesium, total hardness, dissolved oxygen, fluoride etc., The usefulness of these parameters in predicting ground water quality characteristics were discussed. Thus an attempt has been made to find the quality of ground water in and around Gobichettipalayam town, suitable for drinking purposes or not.

  19. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  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. The native ant, Tapinoma melanocephalum, improves the survival of an invasive mealybug, Phenacoccus solenopsis, by defending it from parasitoids.

    Science.gov (United States)

    Feng, Dong-Dong; Michaud, J P; Li, Pan; Zhou, Zhong-Shi; Xu, Zai-Fu

    2015-10-27

    Mutualistic ants can protect their partners from natural enemies in nature. Aenasius bambawalei is an important parasitoid of the the invasive mealybug Phenacoccus solenopsis. We hypothesized that mutualism between native ants and mealybugs would favor survival of mealybugs. To test this, we examined effects of tending by the native mutualistic ant Tapinoma melanocephalum on growth of P. solenopsis colonies on Chinese hibiscus, Hibiscus rosa-sinensis, in a field setting. Ant workers with access to honeydew of mealybugs lived much longer than those provisioned only with water in the laboratory, and number of ant workers foraging increased significantly with growth of mealybug colonies in the field. In later observations, there were significant differences in densities of mealybugs between ant-tended and -excluded treatments. Survival rate of mealybugs experiencing parasitoid attack was significantly higher on ant-tended plants than on ant-excluded plants. When the parasitoid was excluded, there was no difference in survival rate of mealybugs between ant-tended and -excluded plants. In most cases, ants directly attacked the parasitoid, causing the parasitoid to take evasive action. We conclude that native ants such as T. melanocephalum have the potential to facilitate invasion and spread of P. solenopsis in China by providing them with protection from parasitoids.

  3. Effect of water potential and antecedent soil moisture on soil erodibility for coarse and fine-grained agricultural soils

    Science.gov (United States)

    Soil erodibility has confounded researchers for decades. Difficulties arise with initiation of motion, pore-water status, physical, and perhaps biological, material properties and type of applied energy (i.e. rainfall, runoff, freeze/thaw, wind). Though specific tests have been developed to determin...

  4. 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

  5. Chromosomal damage and EROD induction in tree swallows (Tachycineta bicolor) along the Upper Mississippi River, Minnesota, USA

    Science.gov (United States)

    Emilie Bigorgne,; Custer, Thomas W.; Dummer, Paul; Erickson, Richard A.; Karouna-Renier, Natalie K.; Schultz, Sandra; Custer, Christine M.; Thogmartin, Wayne E.; Cole W. Matson,

    2015-01-01

    The health of tree swallows, Tachycineta bicolor, on the Upper Mississippi River (UMR) was assessed in 2010 and 2011 using biomarkers at six sites downriver of Minneapolis/St. Paul, MN metropolitan area, a tributary into the UMR, and a nearby lake. Chromosomal damage was evaluated in nestling blood by measuring the coefficient of variation of DNA content (DNA CV) using flow cytometry. Cytochrome P450 1A activity in nestling liver was measured using the ethoxyresorufin-O-dealkylase (EROD) assay, and oxidative stress was estimated in nestling livers via determination of thiobarbituric acid reacting substances (TBARS), reduced glutathione (GSH), oxidized glutathione (GSSG), the ratio GSSG/GSH, total sulfhydryl, and protein bound sulfhydryl (PBSH). A multilevel regression model (DNA CV) and simple regressions (EROD and oxidative stress) were used to evaluate biomarker responses for each location. Chromosomal damage was significantly elevated at two sites on the UMR (Pigs Eye and Pool 2) relative to the Green Mountain Lake reference site, while the induction of EROD activity was only observed at Pigs Eye. No measures of oxidative stress differed among sites. Multivariate analysis confirmed an increased DNA CV at Pigs Eye and Pool 2, and elevated EROD activity at Pigs Eye. These results suggest that the health of tree swallows has been altered at the DNA level at Pigs Eye and Pool 2 sites, and at the physiological level at Pigs Eye site only.

  6. 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...

  7. Asteroid surface archaeology: Identification of eroded impact structures by spectral properties on (4) Vesta

    Science.gov (United States)

    Hoffmann, M.; Nathues, A.; Schäfer, M.; Schmedemann, N.; Vincent, J.; Russell, C.

    2014-07-01

    Introduction: Vesta's surface material is characterized as a deep regolith [1,2], mobilized by countless impacts. The almost catastrophic impact near Vesta's south pole, which has created the Rheasilvia basin, and the partly overlapping older impact of similar size, Veneneia, have not only reshaped the areas of their interior (roughly 50 % of the Vesta surface), but also emplaced each time a huge ejecta blanket of similar size, thus covering the whole remaining surface. In this context, pristine and even younger morphologic features have been erased. However, the spectral signatures of the early differentiation and alteration products by impacts have partially remained in situ. While near the north pole several large old eroded impact features are visible, the equatorial zone close to the basin rims seems to be void of those. Since it is unlikely, that this zone has been entirely avoided by large projectiles, in this area the results of such impacts may have left morphologically not detectable remnants: Individual distribution of particle sizes and altered photometric properties, excavated layers, shock metamorphism, melt generation inside particles and on macroscopic scales, and emplacement of exogenous projectile material. An analysis by color ratio images and spatial profiles of diagnostic spectral parameters reveals such features. Results: Based on local spectroscopic evidence we have detected eroded impact features of three categories: 1) Small craters with diameters of a few kilometers, 2) Large craters or, if even larger, incipient impact basins, 3) Sub-global ejecta blankets. The eastern part of Feralia Planitia, diameter 140 km, has little evidence of a round outline in the shape model, but it features spectral gradients towards its center. A feature of similar size, centered north of Lucaria Tholus becomes only visible by a similar spectra gradient and a circular outline in specific spectral ratio mosaics. These features seem to be related to the

  8. 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

  9. Effect of Various Organic Matter stimulates Bacteria and Arbuscular Mycorrhizal Fungi Plantations on Eroded Slopes in Nepal

    Science.gov (United States)

    Shrestha Vaidya, G.; Shrestha, K.; Wallander, H.

    2009-04-01

    Erosion resulting from landslides is a serious problem in mountainous countries such as Nepal. To restore such sites it is essential to establish plant cover that protects the soil and reduces erosion. Trees and shrubs on the lower hillsides in Nepal form symbiosis with arbuscular mycorrhizal (AM) fungi and these fungi are important for the uptake of mineral nutrients from the soil. In addition, the mycelia formed by these fungi have an important function in stabilizing the soil. The success of plantations of these eroded slopes is therefore highly dependent on the extent of mycorrhizal colonization of the plants. Mycorrhizal fungi growing in symbiosis with plants are essential in this respect because they improve both plant and nutrient uptake and soil structure. We investigated the influence of organic matter and P amendment on recently produced biomass of bacteria and arbuscular mycorrhizal (AM) fungi in eroded slopes in Nepal. Eroded soil mixed with different types of organic matter was placed in mesh bags which were buried around the trees of Bauhinia purpurea and Leucaena diversifolia .This experiment were done in two seasons ( (the wet and the dry season). Signature fatty acids were used to determine bacterial and AM fungal biomass after the six month intervals. The amount and composition of AM fungal spores were analyzed in the mesh bags from the wet and dry seasons. More microbial biomass was produced during wet season than during dry season. Further more, organic matter addition enhanced the production of AM fungal and bacterial biomass during both seasons. The positive influence of organic matter addition on AM fungi could be an important contribution to plant survival, growth and nutrient composition in the soil in plantations on eroded slopes. Different AM spore communities and bacterial profiles were obtained with different organic amendments and this suggests a possible way of selecting for specific microbial communities in the management of eroded

  10. National invasive species program

    Science.gov (United States)

    Anna Rinick

    2007-01-01

    The structure and function of the National Invasive Species Council was presented below. The names and contact information for the USDA Invasive Species coordinators as of February 2006 were presented on the next page.

  11. Polar bear hepatic cytochrome P450: Immunochemical quantitation, EROD/PROD activity and organochlorines

    Energy Technology Data Exchange (ETDEWEB)

    Letcher, R.J.; Norstrom, R.J. [Carleton Univ., Ottawa, Ontario (Canada). Centre for Analytical and Environmental Chemistry]|[Environment Canada, Ottawa, Ontario (Canada). Canadian Wildlife Service

    1994-12-31

    Polar bears (Ursus maritimus) are an ubiquitous mammal atop the arctic marine food chain and bioaccumulate lipophilic environmental contaminants. Antibodies prepared against purified rat liver cytochrome P450-1 Al, -1 A2, -2Bl and -3Al enzymes have been found to cross-react with structurally-related orthologues present in the hepatic microsomes of wild polar bears, immunochemically determined levels of P450-1 A and -2B proteins in polar bear liver relative to liver of untreated rats suggested enzyme induction, probably as a result of exposure to xenobiotic contaminants. Optical density quantitation of the most immunochemically responsive isozymes P450-I Al, -IA2 and -2Bi to polygonal rabbit anti-rat P450-IA/IA2 sera and -2BI antibodies in hepatic microsomes of 13 adult male polar bars from the Resolute Bay area of the Canadian Arctic is presented. Correlations with EROD and PROD catalytic activities and levels of organochlorines, such as polychlorinated biphenyls (PCBs), 1,1-dichloro-2,2-bis(4-chlorophenyl)ethene (p,p-DDE) and their methyl sulfone (MeSO2-) metabolites are made to determine if compound-specific enzyme induction linkages exist. Inter-species immunochemical quantitation of isozymic P450 cytochromes can serve as an indicator of exposure to biologically active contaminant.

  12. Self-similar evolution of 2D aquatic dunes over an erodible bed

    Science.gov (United States)

    Doppler, Delphine; Lagrée, Pierre Yves; Gondret, Philippe; Rabaud, Marc

    2015-11-01

    Scale invariance of shape is a common feature of erosion patterns, such as barchan dunes, sand ripples under shoaling waves or scour holes. Due to their universal and fascinating crescentic shape, barchans dunes have received much attention and scaling laws have been deduced from field observations, satellite images and laboratory experiments. On the other hand, the dynamical long term evolution of ripples and dunes formed over an erodible bed has been far less studied while the temporal behavior of erosion patterns contains substantial information on the physical processes involved. Here, we present experimental results obtained in a linear, quasi-2D closed water channel. When a granular bed is submitted to a uniform shear flow, periodic sand ripples appear all along the channel. We found that the first ripple near the channel inlet exhibit unreported long-term scale-invariant growth. The self-similar dune shape and power-law growth exponent are extracted by image processing for several flow velocity. A simple linear model is built using mass conservation and a granular flux law, so that the bed form is described by a self-similar order 2 linear system. Experimental data fit nicely with the model results.

  13. Irrigation and Maize Cultivation Erode Plant Diversity Within Crops in Mediterranean Dry Cereal Agro-Ecosystems

    Science.gov (United States)

    Fagúndez, Jaime; Olea, Pedro P.; Tejedo, Pablo; Mateo-Tomás, Patricia; Gómez, David

    2016-07-01

    The intensification of agriculture has increased production at the cost of environment and biodiversity worldwide. To increase crop yield in dry cereal systems, vast farmland areas of high conservation value are being converted into irrigation, especially in Mediterranean countries. We analyze the effect of irrigation-driven changes on the farm biota by comparing species diversity, community composition, and species traits of arable plants within crop fields from two contrasting farming systems (dry and irrigated) in Spain. We sampled plant species within 80 fields of dry wheat, irrigated wheat, and maize (only cultivated under irrigation). Wheat crops held higher landscape and per field species richness, and beta diversity than maize. Within the same type of crop, irrigated wheat hosted lower plant diversity than dry wheat at both field and landscape scales. Floristic composition differed between crop types, with higher frequencies of perennials, cosmopolitan, exotic, wind-pollinated and C4 species in maize. Our results suggest that irrigation projects, that transform large areas of dry cereal agro-ecosystems into irrigated crop systems dominated by maize, erode plant diversity. An adequate planning on the type and proportion of crops used in the irrigated agro-ecosystems is needed in order to balance agriculture production and biodiversity conservation.

  14. 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.

  15. Effect of Artificial Saliva on the Apatite Structure of Eroded Enamel

    International Nuclear Information System (INIS)

    Wang, X.; Mihailova, B.; Heidrich, S.; Bismayer, U.; Wang, X.; Klocke, A.; Klocke, A.

    2011-01-01

    Citric acid-induced changes in the structure of the mineral component of enamel stored in artificial saliva were studied by attenuated total reflectance infrared spectroscopy as well as complementary electron probe microanalysis and scanning electron microscopy. The results indicate that the application of artificial saliva for several hours (the minimum time period proved is 4 h) leads to slight, partial recovering of the local structure of eroded enamel apatite. However, artificial saliva surrounding cannot stop the process of loosening and breaking of P-O-Ca atomic linkages in enamel subjected to multiple citric acid treatments. Irreversible changes in the atomic bonding within 700 nm thick enamel surface layer are observed after three times exposure for 1 min to aqueous solution of citric acid having a ph value of 2.23, with a 24-hour interval between the individual treatments. The additional treatment with basic fluoride-containing solutions (1.0% NaF) did not demonstrate a protective effect on the enamel apatite structure per se.

  16. Sex-ratio control erodes sexual selection, revealing evolutionary feedback from adaptive plasticity.

    Science.gov (United States)

    Fawcett, Tim W; Kuijper, Bram; Weissing, Franz J; Pen, Ido

    2011-09-20

    Female choice is a powerful selective force, driving the elaboration of conspicuous male ornaments. This process of sexual selection has profound implications for many life-history decisions, including sex allocation. For example, females with attractive partners should produce more sons, because these sons will inherit their father's attractiveness and enjoy high mating success, thereby yielding greater fitness returns than daughters. However, previous research has overlooked the fact that there is a reciprocal feedback from life-history strategies to sexual selection. Here, using a simple mathematical model, we show that if mothers adaptively control offspring sex in relation to their partner's attractiveness, sexual selection is weakened and male ornamentation declines. This weakening occurs because the ability to determine offspring sex reduces the fitness difference between females with attractive and unattractive partners. We use individual-based, evolutionary simulations to show that this result holds under more biologically realistic conditions. Sexual selection and sex allocation thus interact in a dynamic fashion: The evolution of conspicuous male ornaments favors sex-ratio adjustment, but this conditional strategy then undermines the very same process that generated it, eroding sexual selection. We predict that, all else being equal, the most elaborate sexual displays should be seen in species with little or no control over offspring sex. The feedback process we have described points to a more general evolutionary principle, in which a conditional strategy weakens directional selection on another trait by reducing fitness differences.

  17. 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

  18. Vortex shedding and morphodynamic response of bed surfaces containing non-erodible roughness elements

    Science.gov (United States)

    McKenna Neuman, Cheryl; Sanderson, Robert Steven; Sutton, Stephen

    2013-09-01

    A series of wind tunnel experiments was carried out to investigate particle entrainment from surfaces in which one or more roughness elements were embedded. Thin sand strips were employed to eliminate impact and ejection, and thus isolate entrainment by fluid drag. The pattern of erosion is consistent with the presence of coherent vortices, inclusive of trailing vortices in the wake flow. The shape and orientation of the roughness element strongly influence this pattern. When an upwind supply of saltators is introduced, the majority of particles within the bed are entrained through impact, with the exception of a sand tail to the lee of the roughness element. That is, the effect of coherent structures within the airflow, as related to spatial variation in the fluid drag exerted on the bed surface, is completely overprinted by the saltation cloud and the blocking of particle trajectories by the upwind face of the roughness element. In a repeated set of experiments, the bed was allowed to fully adjust its morphology to the transport system. In this case, particle entrainment did not selectively occur within the zone of wake flow, and by inference the fluid stress across the test surface appeared to be uniform. These experiments support the hypothesis that vortex annihilation occurs on morphodynamically adjusted surfaces. In summary, the system response to the emergence of non-erodible roughness elements on surfaces affected by wind erosion involves a suite of geophysical processes, each of which attains varied levels of dominance within a given morphodynamic domain.

  19. 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).

  20. The Fate and Stability of Eroding Wetland Soil Carbon in a Subsiding Deltaic Coastal Plain

    Science.gov (United States)

    White, J. R.; Steinmuller, H.; Chambers, L. G.; Fontenot, A.

    2017-12-01

    Coastal wetlands can respond to rapid rates of relative sea level rise via wetland submergence and/or erosion, which occur when wetlands are unable to vertically accrete to keep pace with sea level rise. As coastal wetlands erode, previously sequestered organic carbon is exposed to oxygen-rich estuarine water. This transition in redox from anaerobic to aerobic condition can trigger increased mineralization rates of decades to centuries'-old soil carbon. Barataria Bay, Louisiana has one of the highest coastal wetland land loss rates in the United States, primarily due to eustatic sea level rise coupled with coastal subsidence. Marsh-edge erosion rates measured over the past two years are on the order of 1.5 meters per year. Meter long soil cores were obtained from vegetated wetland sites and sectioned into 11 intervals to investigate aerobic and anaerobic mineralization rates with depth. In surface soils, organic carbon mineralization rates averaged 16 times greater than anaerobic mineralization rates. In deeper, older soils, the aerobic mineralization rate was still an order of magnitude greater than the anaerobic rate, suggesting a significant portion of this older, soil carbon is readily cycling back to the atmosphere after erosion followed by mineralization by microorganisms. These results have consequences for increased atmospheric CO2 concentrations in the future, as stable coastlines worldwide will be subjected to Barataria-bay levels of sea level rise in the next 50-75 years.

  1. Labile organic carbon regulates phosphorus release from eroded soil transported into anaerobic coastal systems.

    Science.gov (United States)

    Lehtoranta, Jouni; Ekholm, Petri; Wahlström, Stella; Tallberg, Petra; Uusitalo, Risto

    2015-03-01

    Coastal eutrophication is expected to increase due to expanding and intensifying agriculture which causes a large amount of soil-associated P to be transported into aquatic systems. We performed anaerobic long-term incubations on field soil to mimic the conditions that eroded soil encounters in brackish sediments. The release of P from soil increased with the amount of labile organic C (acetate) addition and decreased with the soil/solution ratio. We deduce that in less-productive brackish systems, microbial Fe reduction allows for the maintenance of the coupled cycling of Fe and P and restricts the amount of P entering the oxic water. In more eutrophic systems, the formation of Fe sulfides as a result of SO4 reduction inactivates Fe, and leads to a higher release of P, thus generating an adverse feedback effect. The dependence of the fate of soil-bound Fe and P on the trophic status of the receiving water should be recognized in eutrophication management.

  2. Effect of Artificial Saliva on the Apatite Structure of Eroded Enamel

    Directory of Open Access Journals (Sweden)

    Xiaojie Wang

    2011-01-01

    Full Text Available Citric acid-induced changes in the structure of the mineral component of enamel stored in artificial saliva were studied by attenuated total reflectance infrared spectroscopy as well as complementary electron probe microanalysis and scanning electron microscopy. The results indicate that the application of artificial saliva for several hours (the minimum time period proved is 4 h leads to slight, partial recovering of the local structure of eroded enamel apatite. However, artificial saliva surrounding cannot stop the process of loosening and breaking of P–O–Ca atomic linkages in enamel subjected to multiple citric acid treatments. Irreversible changes in the atomic bonding within 700 nm thick enamel surface layer are observed after three times exposure for 1 min to aqueous solution of citric acid having a pH value of 2.23, with a 24-hour interval between the individual treatments. The additional treatment with basic fluoride-containing solutions (1.0% NaF did not demonstrate a protective effect on the enamel apatite structure per se.

  3. 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

  4. RNAi drives nonreciprocal translocations at eroding chromosome ends to establish telomere-free linear chromosomes.

    Science.gov (United States)

    Begnis, Martina; Apte, Manasi S; Masuda, Hirohisa; Jain, Devanshi; Wheeler, David Lee; Cooper, Julia Promisel

    2018-04-13

    The identification of telomerase-negative HAATI (heterochromatin amplification-mediated and telomerase-independent) cells, in which telomeres are superseded by nontelomeric heterochromatin tracts, challenged the idea that canonical telomeres are essential for chromosome linearity and raised crucial questions as to how such tracts translocate to eroding chromosome ends and confer end protection. Here we show that HAATI arises when telomere loss triggers a newly recognized illegitimate translocation pathway that requires RNAi factors. While RNAi is necessary for the translocation events that mobilize ribosomal DNA (rDNA) tracts to all chromosome ends (forming "HAATI rDNA " chromosomes), it is dispensable for HAATI rDNA maintenance. Surprisingly, Dicer (Dcr1) plays a separate, RNAi-independent role in preventing formation of the rare HAATI subtype in which a different repetitive element (the subtelomeric element) replaces telomeres. Using genetics and fusions between shelterin components and rDNA-binding proteins, we mapped the mechanism by which rDNA loci engage crucial end protection factors-despite the absence of telomere repeats-and secure end protection. Sequence analysis of HAATI rDNA genomes allowed us to propose RNA and DNA polymerase template-switching models for the mechanism of RNAi-triggered rDNA translocations. Collectively, our results reveal unforeseen roles for noncoding RNAs (ncRNAs) in assembling a telomere-free chromosome end protection device. © 2018 Begnis et al.; Published by Cold Spring Harbor Laboratory Press.

  5. 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

  6. [Effect of topical iron, fluoride application on eroded enamel in vitro].

    Science.gov (United States)

    Zhang, Yue; Chong, Yan; Huang, Rui-zhe

    2016-04-01

    To evaluate the effect of supplementation containing iron and/or fluoride on eroded enamel in vitro. Eighty enamel specimens collected in orthodontic treatments were randomly allocated into 4 groups of 20 samples each: C (control,deionized water); Fe(2+)(15 mmol/L FeSO(4)); F(-)(1.23% NaF) and Fe(2+)+ F(-)(15 mmol/L FeSO(4) and 1.23% NaF ). Before all samples submitted to 6 alternating demineralization and remineralization cycles, they were pre-treated with one of the experimental solutions for 1 minute. One complete cycle consisted of the following steps: ①demineralization in 5 mL beverage (Coca-Cola, pH=2.58) for 5 minutes under gentle agitation; ②remineralization in 5 mL artificial saliva for 1 hour at 37°C. The effect of erosion was observed by enamel surface morphology and measured by superficial micro-hardness (SMH). One-way ANOVA was performed using SPSS18.0 software package for analysis of the data. The SMH of enamel after erosion by carbonated drinks was significantly lower than the SMH before erosion. When ferrous sulfate with or without fluoride was tested for the prevention of enamel demineralization, there was statistically significant increase in the SMH of enamel in comparison with the control (Pfluorine treatment ,and the damage degree of the enamel surface were reduced compared with the control. Iron and/or fluoride was shown to be effective to enhance the acid resistance of enamel,while the combined use of fluoride and iron in group Fe(2+)+F(-)had no cumulative effects.

  7. 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

  8. 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.

  9. Soil profile dynamics in an eroding soil landscape - a catena through a kettle hole

    Science.gov (United States)

    Gerke, Horst H.; Kaczorek, Danuta; Hierold, Wilfried; Deumlich, Detlef; Koszinski, Sylvia; Ellerbrock, Ruth H.; Sommer, Michael

    2015-04-01

    The arable hummocky ground moraine soil landscapes are characterized by a spatial continuum of more or less eroded soils at hilltops and slopes, and by colluviated soils in topographic depressions. After removal of forest in the middle ages, colluvium started covering the pre-existing Histosols and Gleysols within and Luvisols in the vicinity of kettle holes. A catena through originally peat-filled kettle-hole has hardly been described with respect to ongoing pedological modifications according to changes in landscape and hydrology. The objective was to derive the lateral continuum of soil horizons by identifying the location of the lateral boundaries between regions of clay mobilization/migration and gleisation (gleyic conditions), peat accumulation, and secondary carbonate accumulation. Data from an intensively-sampled field in northeastern Germany are presented. The start of colluviation could be dated by tree ring analyses of a buried stem. The location of the fossil topsoil A and peat horizons was determined from a dense grid of auger holes and geophysical explorations. In addition to older processes in the landscape, also younger redoximorphic processes were indicating changes in soil hydraulic properties and a modified hydrology of the arable soil landscape. We found in micromorphological analyses of soil thin sections that clay migration is an ongoing process; samples indicated vertical gradients in C-contents and secondary carbonate accumulation. The clay mobilization in the colluvium and the migration into the fossil horizons seemed to depend on the direction of soil water movement; anisotropic hydraulic conductivity indicated a potential for lateral water movement. The catena data suggest that the soil landscape development was relatively dynamic; the results may allow the reconstruction of former land surfaces, soil distributions, and erosion rates and may help predicting future developments.

  10. Granulation Tissue Eroding the Subchondral Bone Also Promotes New Bone Formation in Ankylosing Spondylitis.

    Science.gov (United States)

    Bleil, Janine; Maier, Rene; Hempfing, Axel; Sieper, Joachim; Appel, Heiner; Syrbe, Uta

    2016-10-01

    We previously suggested that fibroblast-rich granulation tissue eroding the subchondral bone is instrumental in the joint remodeling that occurs in ankylosing spondylitis (AS). The purpose of this study was to determine if this granulation tissue also carries bone-forming capabilities, which we approached by searching for bone-forming cells (hypertrophic chondrocytes, osteoblasts) in its vicinity. We also assessed adipogenic tissue transformation, which has been suggested to be an intermediate feature in AS bone formation based on imaging studies. The facet joints of AS patients, osteoarthritis (OA) patients, and autopsy subjects (controls) were screened for subchondral granulation tissue. We searched for hypertrophic chondrocytes by assessing RUNX-2, type X collagen, and matrix metalloproteinase 13 (MMP-13) expression, for osteoblasts by analyzing RUNX-2, CD56, and type I collagen expression, as well as for signs of new bone formation. Adipocytes and lipid accumulation were assessed in Safranin O-stained sections. In the joints of AS and OA patients, RUNX-2-positive cells were found to be lining the granulation tissue. These cells coexpressed type I collagen but lacked type X collagen and MMP-13 expression, confirming their osteoblastic nature. In 91% of AS joints and in 20% of OA joints (P granulation tissue and the cartilage. Joints containing bony spots showed greater replacement of the adjacent bone marrow by granulation tissue than did joints without bone formation (P granulation tissue often contained adipocytes and lipid accumulations. Replacement of the subchondral bone marrow by fat tissue was also frequently found but was not associated with new bone formation. The subchondral granulation tissue carries osteoblasts, which promote new bone formation, leading to intraarticular ankylosis of the facet joints in AS. © 2016, American College of Rheumatology.

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

    Energy Technology Data Exchange (ETDEWEB)

    Verbeek, A. [Chemex Labs Alberta Inc., Edmonton, Alberta (Canada); Mackay, W. [Univ. of Alberta, Edmonton, Alberta (Canada); Birkholz, D. [Enviro-Test Labs., Edmonton, Alberta (Canada)

    1995-12-31

    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{sub 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{sup 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 {beta}-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 {beta}-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 {beta}-naphthoflavone.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Short lag times for invasive tropical plants: evidence from experimental plantings in Hawai'i.

    Science.gov (United States)

    Daehler, Curtis C

    2009-01-01

    The lag time of an invasion is the delay between arrival of an introduced species and its successful spread in a new area. To date, most estimates of lag times for plants have been indirect or anecdotal, and these estimates suggest that plant invasions are often characterized by lag times of 50 years or more. No general estimates are available of lag times for tropical plant invasions. Historical plantings and documentation were used to directly estimate lag times for tropical plant invasions in Hawai'i. Historical planting records for the Lyon Arboretum dating back to 1920 were examined to identify plants that have since become invasive pests in the Hawaiian Islands. Annual reports describing escape from plantings were then used to determine the lag times between initial plantings and earliest recorded spread of the successful invaders. Among 23 species that eventually became invasive pests, the average lag time between introduction and first evidence of spread was 14 years for woody plants and 5 years for herbaceous plants. These direct estimates of lag times are as much as an order of magnitude shorter than previous, indirect estimates, which were mainly based on temperate plants. Tropical invaders may have much shorter lag times than temperate species. A lack of direct and deliberate observations may have also inflated many previous lag time estimates. Although there have been documented cases of long lag times due to delayed arrival of a mutualist or environmental changes over time, this study suggests that most successful invasions are likely to begin shortly after arrival of the plant in a suitable habitat, at least in tropical environments. Short lag times suggest that controlled field trials may be a practical element of risk assessment for plant introductions.

  17. Simulating dam-break over an erodible embankment using SWE-Exner model and semi-implicit staggered scheme

    Science.gov (United States)

    Ambara, M. D.; Gunawan, P. H.

    2018-03-01

    The impact of a dam-break wave on an erodible embankment with a steep slope has been studied recently using both experimental and numerical approaches. In this paper, the semi-implicit staggered scheme for approximating the shallow water-Exner model will be elaborated to describe the erodible sediment on a steep slope. This scheme is known as a robust scheme to approximate shallow water-Exner model. The results are shown in a good agreement with the experimental data. The comparisons of numerical results with data experiment using slopes Φ = 59.04 and Φ = 41.42 by coefficient of Grass formula Ag = 2 × 10‑5 and Ag = 10‑5 respectively are found the closest results to the experiment. This paper can be seen as the additional validation of semi-implicit staggered scheme in the paper of Gunawan, et al (2015).

  18. The function tests of ignitor electrode system and determination of the eroded mass of the ignitor cathode material

    International Nuclear Information System (INIS)

    Lely Susita R M; Sudjatmoko; Bambang Siswanto; Agus Purwadi; Ihwanul Aziz

    2015-01-01

    Ignitor electrode systems which serves to initiate plasma discharge consists of two ignitor electrodes equipped with a unit of ignitor discharge power supply. Ignitor electrode system consists of a cathode, an anode and an insulator between the cathode and the anode. Ignitor discharge power supply system has a 10 kV voltage specification and energy of 100 mJ, the voltage flowing through the anode and the insulator will form plasma spot on the surface of the cathode. Discharge currents that flow to the cathode becomes larger, then the resulting plasma spot also becomes larger so eroded cathode material becomes greater. In this study the ignitor electrode system function test was done, and the results of function test it can determine the mass and the particle size of the ignitor cathode material eroded which can be correlated to the age of the cathode due to the loss of material at the surface of the cathode after forming plasma spot. On the function and performance tests of the plasma cathode electron source were obtained the electron beam current of 34.3 A with a pulse width of 136 μs, for the plasma spot current of 10.58 A with a pulse width of 39 μs. The specification of cathode used in the ignitor electrode system is as follow: magnesium cathode materials in the form of a cylinder having a diameter of 6 mm and length of 20 mm. For repetition frequency of plasma spot of 10 Hz, cathode material will be eroded and diminished throughout of 17.64 μm, while the cathode material eroded to form a cone, then the cathode material will be reduced along 26.46 μm for a 5 hours of testing time of plasma cathode electron source. Form the erosion of the cathode materials is influenced by the current of plasma spot, pulse width and the vacuum of the plasma vessel. (author)

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

    OpenAIRE

    Ayoubi, S.A; M. H. Alizadeh

    2005-01-01

    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 variabil...

  20. 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.

  1. 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.

  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 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. 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

  4. 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...

  5. Ecology of forest insect invasions

    Science.gov (United States)

    E.G. Brockerhoff; A.M. Liebhold

    2017-01-01

    Forests in virtually all regions of the world are being affected by invasions of non-native insects. We conducted an in-depth review of the traits of successful invasive forest insects and the ecological processes involved in insect invasions across the universal invasion phases (transport and arrival, establishment, spread and impacts). Most forest insect invasions...

  6. 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 science s (social aspects to be 5.7) Impact factor: 4.900, year: 2016

  7. The 2010 Retirement Confidence Survey: confidence stabilizing, but preparations continue to erode.

    Science.gov (United States)

    Helman, Ruth; Copeland, Craig; VanDerhei, Jack

    2010-03-01

    20TH ANNUAL RCS: The 2010 Retirement Confidence Survey-the 20th annual wave of this survey-finds that the record-low confidence levels measured during the past two years of economic decline appear to have bottomed out. The percentage of workers veryconfident about having enough money for a comfortable retirement has stabilized at 16 percent, which is statistically equivalent to the 20-year low of 13 percent measured in 2009 (Fig. 1, pg. 7). Retiree confidence about having a financially secure retirement has also stabilized, with 19 percent saying now they are very confident (statistically equivalent to the 20 percent measured in 2009) (Fig. 2, pg. 8). Worker confidence about paying for basic expenses in retirement has rebounded slightly, with 29 percent now saying they are very confident about having enough money to pay for basic expenses during retirement (up from 25 percent in 2009, but still down from 34 percent in 2008) (Fig. 3, pg. 9). PREPARATIONS STILL ERODING: Fewer workers report that they and/or their spouse have saved for retirement (69 percent, down from 75 percent in 2009 but statistically equivalent to 72 percent in 2008) (Fig. 11, page 14). Moreover, fewer workers say that they and/or their spouse are currently saving for retirement (60 percent, down from 65 percent in 2009 but statistically equivalent to percentages measured in other years) (Fig. 13, pg. 15). MORE PEOPLE HAVE NO SAVINGS AT ALL: An increased percentage of workers report they have virtually no savings and investments. Among RCS workers providing this type of information, 27 percent say they have less than $1,000 in savings (up from 20 percent in 2009). In total, more than half of workers (54 percent) report that the total value of their household's savings and investments, excluding the value of their primary home and any defined benefit plans, is less than $25,000 (Fig. 14, pg. 16). CLUELESS ABOUT SAVINGS GOALS: Many workers continue to be unaware of how much they need to save for

  8. 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; de Queiroz, Rubens T; Arnan, Xavier

    2018-03-05

    1.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. 2.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 northeastern Brazil. More specifically, we examined interactions between plants bearing extrafloral nectaries (EFNs) and ants. We analyzed whether differences in network specialization could arise from environmentally mediated variation in the species composition, namely via the replacement of specialist by generalist species. 3.We characterized these ant-plant networks in 15 plots (20 x 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 '. 4.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 behavior, not species composition

  9. 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"

  10. [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.

  11. 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.

  12. Invasion biology of thrips.

    Science.gov (United States)

    Morse, Joseph G; Hoddle, Mark S

    2006-01-01

    Thrips are among the stealthiest of insect invaders due to their small size and cryptic habits. Many invasive thrips are notorious for causing extensive crop damage, vectoring viral diseases, and permanently destabilizing IPM systems owing to irruptive outbreaks that require remediation with insecticides, leading to the development of insecticide resistance. Several challenges surface when attempting to manage incursive thrips species. Foremost among these is early recognition, followed by rapid and accurate identification of emergent pest species, elucidation of the region of origin, development of a management program, and the closing of conduits for global movement of thrips. In this review, we examine factors facilitating invasion by thrips, damage caused by these insects, pre- and post-invasion management tactics, and challenges looming on the horizon posed by invasive Thysanoptera, which continually challenge the development of sustainable management practices.

  13. Long-Term Bond Strength of Self-Etch Adhesives to Normal and Artificially Eroded Dentin: Effect of Relative Humidity and Saliva Contamination.

    Science.gov (United States)

    Amsler, Fabienne; Peutzfeldt, Anne; Lussi, Adrian; Flury, Simon

    2017-01-01

    To investigate the effect of relative humidity and saliva contamination on short- and long-term bond strength of two self-etch adhesives to normal and artificially eroded dentin. A total of 480 dentin specimens were produced from extracted human molars. Half of the specimens (n = 240) were left untreated (normal dentin) whereas the other half (n = 240) were artificially eroded. The specimens were treated with Clearfil SE Bond (CSE) or Scotchbond Universal (SBU), and composite (Filtek Z250) was applied to the treated dentin surface under four experimental conditions: at a relative humidity of 45% or 85% without/with human saliva contamination. Shear bond strength (SBS) was measured after storage for 24 h (100% humidity; 37°C) or 1 year (tap water; 37°C). SBS results were statistically analyzed with a nonparametric ANOVA followed by Wilcoxon-Mann-Whitney tests (significance level: α = 0.05). SBS was significantly influenced by the dentin substrate (normal or artificially eroded dentin) and adhesive (p  CSE on normal dentin (19.2) > SBU on artificially eroded dentin (17.1) > CSE on artificially eroded dentin (10.9). On normal dentin, the two self-etch adhesives showed stable bond strength over time even under adverse conditions such as high relative humidity and saliva contamination. However, erosively altered dentin had a detrimental effect on the bond strength of both the adhesives investigated.

  14. 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

  15. 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.

  16. Relevance of macrozoobenthic grazers to understand the dynamic behaviour of sediment erodibility and microphytobenthos resuspension in sunny summer conditions

    Science.gov (United States)

    Orvain, Francis; Guizien, Katell; Lefebvre, Sébastien; Bréret, Martine; Dupuy, Christine

    2014-09-01

    The quantification of overall microphytobenthos productivity should include the export of biomass from the intertidal zone during high tides, which implies refined estimates and concepts of erosion parameters. For the first time, the export of microphytobenthic cells was assessed over an intertidal mudflat in the Marennes-Oléron Bay, France, during a complete spring/neap tide modulation. In the summer of 2008, resuspension rates of chl-a exported only reached 2.5% of the standing stock of benthic diatoms on each day. Sedimentary factors failed to explain any variation regarding bed and microphytobenthos erodibility. During the early fluff layer erosion phase, there were negative effects of grazing activities exerted by motile infauna (Peringia ulvae) on erosion fluxes of chl-a, while there was a related positive correlation with pheopigment proportion. The erosion process plays an important role in this vegetal-herbivore interaction by reinforcing the decline of the microphytobenthic biomass and provoking a catastrophic shift to mass erosion after a sequence of several days of co-occurring intense grazing by snails and chl-a decline. During mass erosion, the biofilm decline explained the variations of sediment erodibility, with a marked negative correlation between bound extracellular polymeric substance (EPS) proteins and critical threshold for bed erosion, in contrast with the commonly observed positive influence of EPS secretion on bed resistance. The complex nature of the effects of EPS by microphytobenthos must be further investigated to unravel their complex role in bioengineering sediments. The increase of protein proportion in EPS could provide specific properties related to hydrophilic features. Nevertheless, the level of grazing pressure by P. ulvae should be so intense that the top-down control must explain this original finding, since there was a positive correlation of proteins in EPS and snail density that could be related to mucus secretion (as a

  17. 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.

  18. Emergent Minimally Invasive Esophagogastrectomy

    Directory of Open Access Journals (Sweden)

    Thomas Fabian

    2017-01-01

    Full Text Available Introduction. Esophageal perforation in the setting of a malignancy carries a high morbidity and mortality. We describe our management of such a patient using minimally invasive approach. Methods. An 83-year-old female presented with an iatrogenic esophageal perforation during the workup of dysphagia. She was referred for surgical evaluation immediately after the event which occurred in the endoscopy suite. Minimally invasive esophagectomy was chosen to provide definitive treatment for both her malignancy and esophageal perforation. Results. Following an uncomplicated operative course, she was eventually discharged to extended care for rehabilitation and remains alive four years after her resection. Conclusion. Although traditional open techniques are the accepted gold standard of treatment for esophageal perforation, minimally invasive esophagectomy plays an important role in experienced hands and may be offered to such patients.

  19. 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

  20. Over-invasion by functionally equivalent invasive species.

    Science.gov (United States)

    Russell, James C; Sataruddin, Nurul S; Heard, Allison D

    2014-08-01

    Multiple invasive species have now established at most locations around the world, and the rate of new species invasions and records of new invasive species continue to grow. Multiple invasive species interact in complex and unpredictable ways, altering their invasion success and impacts on biodiversity. Incumbent invasive species can be replaced by functionally similar invading species through competitive processes; however the generalized circumstances leading to such competitive displacement have not been well investigated. The likelihood of competitive displacement is a function of the incumbent advantage of the resident invasive species and the propagule pressure of the colonizing invasive species. We modeled interactions between populations of two functionally similar invasive species and indicated the circumstances under which dominance can be through propagule pressure and incumbent advantage. Under certain circumstances, a normally subordinate species can be incumbent and reject a colonizing dominant species, or successfully colonize in competition with a dominant species during simultaneous invasion. Our theoretical results are supported by empirical studies of the invasion of islands by three invasive Rattus species. Competitive displacement is prominent in invasive rats and explains the replacement of R. exulans on islands subsequently invaded by European populations of R. rattus and R. norvegicus. These competition outcomes between invasive species can be found in a broad range of taxa and biomes, and are likely to become more common. Conservation management must consider that removing an incumbent invasive species may facilitate invasion by another invasive species. Under very restricted circumstances of dominant competitive ability but lesser impact, competitive displacement may provide a novel method of biological control.

  1. 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...

  2. Mechanisms Regulating Glioma Invasion

    Science.gov (United States)

    Paw, Ivy; Carpenter, Richard C.; Watabe, Kounosuke; Debinski, Waldemar; Lo, Hui-Wen

    2015-01-01

    Glioblastoma (GBM) is the most aggressive, deadliest, and most common brain malignancy in adults. Despite the advances made in surgical techniques, radiotherapy and chemotherapy, the median survival for GBM patients has remained at a mere 14 months. GBM poses several unique challenges to currently available treatments for the disease. For example, GBM cells have the propensity to aggressively infiltrate/invade into the normal brain tissues and along the vascular tracks, which prevents complete resection of all malignant cells and limits the effect of localized radiotherapy while sparing normal tissue. Although anti-angiogenic treatment exerts anti-edematic effect in GBM, unfortunately, tumors progress with acquired increased invasiveness. Therefore, it is an important task to gain a deeper understanding of the intrinsic and post-treatment invasive phenotypes of GBM in hopes that the gained knowledge would lead to novel GBM treatments that are more effective and less toxic. This review will give an overview of some of the signaling pathways that have been shown to positively and negatively regulate GBM invasion, including, the PI3K/Akt, Wnt, sonic hedgehog-GLI1, and microRNAs. The review will also discuss several approaches to cancer therapies potentially altering GBM invasiveness. PMID:25796440

  3. 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

  4. Management of invasive species

    DEFF Research Database (Denmark)

    Schou, Jesper Sølver; Jensen, Frank

    In this paper, we conduct a number of cost-benefit analyses to clarify whether the establishment of invasive species should be prevented or the damage of such species should be mitigated after introduction. We use the potential establishment of ragweed in Denmark as an empirical case. The main...... of information externalities, altruistic preferences, possible catastrophic events and ethical considerations....

  5. Two invasive acacia species secure generalist pollinators in invaded communities

    Science.gov (United States)

    Montesinos, Daniel; Castro, Sílvia; Rodríguez-Echeverría, Susana

    2016-07-01

    Exotic entomophilous plants need to establish effective pollinator interactions in order to succeed after being introduced into a new community, particularly if they are obligatory outbreeders. By establishing these novel interactions in the new non-native range, invasive plants are hypothesised to drive changes in the composition and functioning of the native pollinator community, with potential impacts on the pollination biology of native co-flowering plants. We used two different sites in Portugal, each invaded by a different acacia species, to assess whether two native Australian trees, Acacia dealbata and Acacia longifolia, were able to recruit pollinators in Portugal, and whether the pollinator community visiting acacia trees differed from the pollinator communities interacting with native co-flowering plants. Our results indicate that in the invaded range of Portugal both acacia species were able to establish novel mutualistic interactions, predominantly with generalist pollinators. For each of the two studied sites, only two other co-occurring native plant species presented partially overlapping phenologies. We observed significant differences in pollinator richness and visitation rates among native and non-native plant species, although the study of β diversity indicated that only the native plant Lithodora fruticosa presented a differentiated set of pollinator species. Acacias experienced a large number of visits by numerous pollinator species, but massive acacia flowering resulted in flower visitation rates frequently lower than those of the native co-flowering species. We conclude that the establishment of mutualisms in Portugal likely contributes to the effective and profuse production of acacia seeds in Portugal. Despite the massive flowering of A. dealbata and A. longifolia, native plant species attained similar or higher visitation rates than acacias.

  6. Invasive Plants -- A Horticultural Perspective

    OpenAIRE

    Niemiera, Alexander Xavier, 1951-; Von Holle, Betsy

    2009-01-01

    This publication explains how nonnative invasive plants are harmful and why you should care, how to predict the invasive potential of a plant, and how gardeners and landscape professionals can make informed choices when choosing plants.

  7. Combined use of PAH levels and EROD activities in the determination of PAH pollution in flathead mullet (Mugil cephalus) caught from the West Black Sea coast of Turkey.

    Science.gov (United States)

    Bozcaarmutlu, Azra; Sapmaz, Canan; Kaleli, Gizem; Turna, Sema; Yenisoy-Karakaş, Serpil

    2015-02-01

    The aim of this study was to determine the extent of polycyclic aromatic hydrocarbon (PAH) pollution by measuring PAH levels and 7-ethoxyresorufin-O-deethylase (EROD) activities in flathead mullet (Mugil cephalus) samples caught from the West Black Sea coast of Turkey. The fish samples were caught in August 2008-2011. The levels of 13 PAHs were measured by high-performance liquid chromatography (HPLC) in the liver of fish. Most of the measured PAHs had three rings (low molecular weight). The frequencies of detection of PAHs were higher in fish samples caught from Zonguldak Harbour and Gülüç Stream Mouth than those from Sakarya River Mouth, Amasra and Kefken. EROD activities and cytochrome P4501A (CYP1A) protein level were also measured in the fish liver microsomes. Highly elevated EROD activities and CYP1A levels were measured in the mullet samples caught from Zonguldak Harbour and Gülüç Stream than those from Amasra and Kefken. The detection of PAHs in the liver of fish samples shows recent exposure to PAHs. The chemical analyses of PAHs and EROD activity results together reflected the extent of PAH pollution in the livers of fish caught from the West Black Sea coast of Turkey. The results indicate that Zonguldak Harbour is the most polluted site in the West Black Sea coast of Turkey.

  8. The effects of Herba Andrographitis hedgerows on soil erodibility and fractal features on sloping cropland in the Three Gorges Reservoir Area.

    Science.gov (United States)

    Chen, Jingjing; He, Binghui; Wang, Xiaoyan; Ma, Yun; Xi, Weimin

    2013-10-01

    To evaluate if hedgerows could improve the soil physicochemical properties and enhance the soil anti-scouring and anti-shearing capabilities, the effects of Herba Andrographitis hedgerows on soil erodibility and fractal features on sloping cropland in the Three Gorges Reservoir Area were investigated. Results showed that: (1) the clay particle accumulation around the hedgerows was significantly affected by the hedgerows; (2) the fractal dimension of soil particles was positively correlated with both silt and clay contents and had a negative linear correlation with sand content; (3) fine-grained content significantly influenced fractal dimension of the soil particles; (4) soil erodibility K was significantly and positively correlated with the sand content (correlation coefficient r=0.870), but significantly and negatively correlated with the silt content (r=-0.538), clay content (r=-0.739), organic carbon content (r=-0.603), the aggregation degree (r=-0.486), and soil fractal dimension (r=-0.538); and (5) the contents of organic matter and clay particles in the soil were found to be the effective indicators for soil erodibility at the Three Gorges Reservoir Area. The hedgerows may improve soil fractal features and decrease soil erodibility. The effective distance between hedgerows on a slope of 10° was less than 6 m.

  9. Erodibility of Titan ice bedrock constrained by laboratory measurements of ice strength and erosion by sediment impacts

    Science.gov (United States)

    Sklar, L. S.; Collins, G. C.; Litwin, K. L.; Polito, P. J.; Zygielbaum, B. R.

    2012-12-01

    Saturn's moon Titan has a remarkably earth-like surface morphology, with branching fluvial networks draining elevated terrain. A paucity of impact craters suggests fluvial dissection is active and that the pace of landscape evolution is rapid. A key limitation on modeling rates of incision by Titan's rivers of liquid methane has been a lack of information on the erodibility of water-ice bedrock at ultra-cold temperatures. Here we report results from laboratory measurements of ice resistance to tensile fracture and rates of erosion of Titan bedrock analogs by low-velocity sediment impacts. We apply these experimental results to modeling fluvial incision, and explore constraints on rates and frequency of channel cutting on Titan. We made test samples of polycrystalline ice with a narrow and wide size distribution of seed ice grains. For some samples we added solid impurities composed of basalt, urea, and ammonium-sulfate, to account for the possibility that Titan's ice bedrock also contains silicates from meteors, organic polymers derived from Titan's atmosphere, and ammonia-based compounds formed by cryovolcanism. The experiments were conducted in a walk-in freezer and environmental chamber, where we varied temperature between 260 and 110 K using dry ice and liquid nitrogen (LN). For terrestrial rocks, resistance to erosion by sediment impacts depends on the kinetic energy required to detach a unit volume, which has been shown to scale with the square of tensile strength. We measured the tensile strength of Titan bedrock analogs using the Brazilian splitting test and found that strength increases with decreasing temperature at 7 kPa/K, for all ice types tested. Ice at Titan temperatures is thus roughly twice as strong as at terrestrial conditions; ice is strengthened by increasing impurity concentrations, finer grain-size distributions, and lower porosity. To replicate erosion of ice bedrock by bedload sediment impacts, we filled a 55-gallon drum with various ice

  10. Metabarcoding dietary analysis of coral dwelling predatory fish demonstrates the minor contribution of coral mutualists to their highly partitioned, generalist diet

    Directory of Open Access Journals (Sweden)

    Matthieu Leray

    2015-06-01

    Full Text Available Understanding the role of predators in food webs can be challenging in highly diverse predator/prey systems composed of small cryptic species. DNA based dietary analysis can supplement predator removal experiments and provide high resolution for prey identification. Here we use a metabarcoding approach to provide initial insights into the diet and functional role of coral-dwelling predatory fish feeding on small invertebrates. Fish were collected in Moorea (French Polynesia where the BIOCODE project has generated DNA barcodes for numerous coral associated invertebrate species. Pyrosequencing data revealed a total of 292 Operational Taxonomic Units (OTU in the gut contents of the arc-eye hawkfish (Paracirrhites arcatus, the flame hawkfish (Neocirrhites armatus and the coral croucher (Caracanthus maculatus. One hundred forty-nine (51% of them had species-level matches in reference libraries (>98% similarity while 76 additional OTUs (26% could be identified to higher taxonomic levels. Decapods that have a mutualistic relationship with Pocillopora and are typically dominant among coral branches, represent a minor contribution of the predators’ diets. Instead, predators mainly consumed transient species including pelagic taxa such as copepods, chaetognaths and siphonophores suggesting non random feeding behavior. We also identified prey species known to have direct negative interactions with stony corals, such as Hapalocarcinus sp, a gall crab considered a coral parasite, as well as species of vermetid snails known for their deleterious effects on coral growth. Pocillopora DNA accounted for 20.8% and 20.1% of total number of sequences in the guts of the flame hawkfish and coral croucher but it was not detected in the guts of the arc-eye hawkfish. Comparison of diets among the three fishes demonstrates remarkable partitioning with nearly 80% of prey items consumed by only one predator. Overall, the taxonomic resolution provided by the metabarcoding

  11. Determination of temperate bird-flower interactions as entangled mutualistic and antagonistic sub-networks: characterization at the network and species levels.

    Science.gov (United States)

    Yoshikawa, Tetsuro; Isagi, Yuji

    2014-05-01

    Most network studies on biological interactions consider only a single interaction type. However, individual species are simultaneously positioned in various types of interactions. The ways in which different network types are merged and entangled, and the variations in network structures between different sympatric networks, require full elucidation. Incorporating interaction types and disentangling complex networks is crucial, because the integration of various network architectures has the potential to alter the stability and co-evolutionary dynamics of the whole network. To reveal how different types of interaction networks are entangled, we focused on the interaction between birds and flowers of temperate plants in Japan, where flower-feeding birds are mainly generalist passerines, acting as pollinators and predators of flowers. Using long-term monitoring data, we investigated the flower-feeding episodes of birds. We constructed the whole network (WN) between birds and plants, separating the network into mutualistic and antagonistic sub-networks (MS and AS, respectively). We investigated structural properties of the three quantified networks and species-level characteristics of the main bird species. For bird species, we evaluated dietary similarity, dietary specialization and shifts of feeding behaviour relative to plant traits. Our results indicate that WN comprises entangled MS and AS, sharing considerable proportions of bird and plant assemblages. We observed distinctive differences in the network structural properties between the two sub-networks. In comparison with AS, MS had lower numbers of bird and plant species, showed lower specialization and modularity and exhibited higher nestedness. At the species level, the Japanese white-eye acted as pollinator, while the brown-eared bulbul acted as both pollinator and predator for large numbers of flowers, based on its behavioural plasticity. Overall, the pattern of avian feeding behaviour was influenced by

  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. Efficacy of different strategies to treat root dentin eroded by liquid or gaseous hydrochloric acid associated with brushing abrasion.

    Science.gov (United States)

    Faraoni, Juliana Jendiroba; Torres Toro, Carmen Victoria; de Matos, Laís Lopes Machado; Palma-Dibb, Regina Guenka

    2018-05-01

    This study aims to evaluate how casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) associated with Nd:YAG or Diode laser affects dentin exposed to hydrochloric acid (HCl) with or without tooth brushing. One hundred and sixty human root dentin blocks were selected after they were initially eroded with liquid HCl (pH 1.2) 3x for one day. The blocks were divided into the following groups: G1- liquid HCl (HCl-l), G2- HCl-l + brushing, G3- gaseous HCl (HCl-g), and G4- HCl-g + brushing. Each group was randomly assigned to the following treatments (n = 10): A) Control (no treatment), B) CPP-ACP, C) CPP-ACP associated with Nd:YAG laser (λ = 1064 nm) (40 mJ, 10 Hz, 0.4 W, 15 s), and D) CPP-ACP associated with Diode laser (λ = 980 nm) (0.5 W, 200 μs, 15 s). The treatment with CPP-ACP (G2, G3 and G4) was applied on the dentine surface for 5 min. Erosion (6x/day/20 s) and erosion (6x/day/20 s) with abrasion (2x/10 s) were performed for five days. Dentin volume loss was determined by 3D confocal laser microscopy. Data were analyzed with two-way ANOVA and Tukey's tests. G1 - CPP-ACP (10.77 ± 1.66) and CPP-ACP associated with Diode laser (9.98 ± 0.89) showed lower volume loss in relation Control group (12.86 ± 0.63) (p < 0.05). G2 - CPP-ACP associated with Diode laser (12.41 ± 1.08) elicited lower volume loss as compared to the Control (14.42 ± 1.24) (p < 0.05). As for G3 and G4, all treatments showed similar volume loss. CPP-ACP and CPP-ACP associated with Diode laser could control dental tissue loss in dentin eroded by liquid HCl. Moreover, CPP-ACP associated with Diode laser could effectively decrease dental tissue loss in dentin exposed to liquid HCl and brushing. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. 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

  15. Minimally Invasive Abdominal Surgery

    OpenAIRE

    Richardson, William S.; Carter, Kristine M.; Fuhrman, George M.; Bolton, John S.; Bowen, John C.

    2000-01-01

    In the last decade, laparoscopy has been the most innovative surgical movement in general surgery. Minimally invasive surgery performed through a few small incisions, laparoscopy is the standard of care for the treatment of gallbladder disease and the gold standard for the treatment of reflux disease. The indications for a laparoscopic approach to abdominal disease continue to increase, and many diseases may be treated with laparoscopic techniques. At Ochsner, laparoscopic techniques have dem...

  16. 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

  17. 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

  18. Numerical modelling of suffusion by discrete element method: a new internal stability criterion based on mechanical behaviour of eroded soil

    Directory of Open Access Journals (Sweden)

    Abdoulaye Hama Nadjibou

    2017-01-01

    Full Text Available Non-cohesive soils subjected to a flow may have a behavior in which fine particles migrate through the interstices of the solid skeleton formed by the large particles. This phenomenon is termed internal instability, internal erosion or suffusion, and can occur both in natural soil deposits and also in geotechnical structures such as dams, dikes or barrages. Internal instability of a granular material is its inability to prevent the loss of its fine particles under flow effect. It is geometrically possible if the fine particles can migrate through the pores of the coarse soil matrix and results in a change in its mechanical properties. In this work, we uses the three-dimensional Particle Flow Code (PFC3D/DEM to study the stability/instability of granular materials and their mechanical behavior. Kenney and Lau criterion sets a safe boundary for engineering design. However, it tends to identify stable soils as unstable ones. The effects of instability and erosion, simulated by clipping fine particles from the grading distribution, on the mechanical behaviour of glass ball samples were analysed. The mechanical properties of eroded samples, in which erosion is simulated and gives a new approach for internal stability. A proposal for a new internal stability criterion is established, it is deduced from the analysis of relations between the mechanical behaviour and internal stability, including material contractance.

  19. Influence of toothbrushing on enamel softening and abrasive wear of eroded bovine enamel: an in situ study.

    Science.gov (United States)

    Rios, Daniela; Honório, Heitor Marques; Magalhães, Ana Carolina; Buzalaf, Marília Afonso Rabelo; Palma-Dibb, Regina Guenka; Machado, Maria Aparecida De Andrade Moreira; da Silva, Salete Moura Bonifácio

    2006-01-01

    This study assessed the surface softening and abrasive wear of eroded bovine enamel with or without the influence of toothbrushing. Five volunteers took part in this in situ study of 5 days. They wore acrylic palatal appliances containing 6 bovine enamel blocks divided in two rows with 3 blocks, which corresponded to the studied groups: erosion without toothbrushing (GI) and erosion with toothbrushing (GII). The blocks were subjected to erosion by immersion of the appliances in a cola drink for 10 minutes, 4 times a day. After that, no treatment was performed in one row (GI), whereas the other row was brushed (GII). The appliance was then replaced into the mouth. Enamel alterations were determined using profilometry and microhardness tests. Data were tested using paired Students t test (p wear values (microm) and percentage of superficial microhardness change (%SMHC) were respectively: GI--2.77 +/- 1.21/91.61 +/- 3.68 and GII--3.80 +/- 0.91/58.77 +/- 11.47. There was a significant difference in wear (p = 0.001) and %SMHC (p = 0.001) between the groups. It was concluded that the wear was more pronounced when associated to toothbrushing abrasion. However, toothbrushing promoted less %SMHC due to the removal of the altered superficial enamel layer.

  20. Numerical modelling of suffusion by discrete element method: a new internal stability criterion based on mechanical behaviour of eroded soil

    Science.gov (United States)

    Abdoulaye Hama, Nadjibou; Ouahbi, Tariq; Taibi, Said; Souli, Hanène; Fleureau, Jean-Marie; Pantet, Anne

    2017-06-01

    Non-cohesive soils subjected to a flow may have a behavior in which fine particles migrate through the interstices of the solid skeleton formed by the large particles. This phenomenon is termed internal instability, internal erosion or suffusion, and can occur both in natural soil deposits and also in geotechnical structures such as dams, dikes or barrages. Internal instability of a granular material is its inability to prevent the loss of its fine particles under flow effect. It is geometrically possible if the fine particles can migrate through the pores of the coarse soil matrix and results in a change in its mechanical properties. In this work, we uses the three-dimensional Particle Flow Code (PFC3D/DEM) to study the stability/instability of granular materials and their mechanical behavior. Kenney and Lau criterion sets a safe boundary for engineering design. However, it tends to identify stable soils as unstable ones. The effects of instability and erosion, simulated by clipping fine particles from the grading distribution, on the mechanical behaviour of glass ball samples were analysed. The mechanical properties of eroded samples, in which erosion is simulated and gives a new approach for internal stability. A proposal for a new internal stability criterion is established, it is deduced from the analysis of relations between the mechanical behaviour and internal stability, including material contractance.

  1. 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.

  2. 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

  3. 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.

  4. Influence of Bristle Stiffness of Manual Toothbrushes on Eroded and Sound Human Dentin – An In Vitro Study

    Science.gov (United States)

    Arnold, Wolfgang H.; Domin, Julia

    2016-01-01

    Aim The aim of this study was to determine the influence of manual toothbrushes with different bristle stiffness on the abrasivity on eroded and sound human dentin. Materials and Methods Dentin specimens were made from impacted third molars and attributed to three groups: erosion-abrasion (EA), abrasion (A) and erosion (E). The specimens from EA and E were treated with 1% citric acid (pH 2.3) for 1 min rinsed, and neutralized with artificial saliva for 15 min. This cycle was repeated five times. Thereafter, specimens from EA and A were treated with three toothbrushes types with different bristle stiffness (soft, medium, and hard) in a custom-made toothbrushing machine. The brushing was performed at a load of 3 N with a toothpaste slurry for 630 s. This procedure was repeated five times, in group EA after each erosion cycle. EA and A groups passed through five cycles with a total of 6300 strokes. The abrasivity was analyzed by contact-free profilometry. Kruskal-Wallis and Mann-Whitney U tests were performed for statistical analysis. Results With respect to bristle stiffness there was no statistically significant difference in dentin loss within the EA group. In group A, a statistically significantly higher dentin loss was found for the soft in comparison to the hard bristles. No statistically significant differences were measured between soft/medium and medium/hard toothbrushes. The amount of dentin loss from specimens in the EA group was significantly higher than in the A group. Conclusions Within the limitations of this study, the dentin loss in the Abrasion group was higher with soft bristles than with hard ones. This result might have an influence on the toothbrush recommendations for patients with non-carious cervical lesions. PMID:27070901

  5. Influence of Bristle Stiffness of Manual Toothbrushes on Eroded and Sound Human Dentin--An In Vitro Study.

    Directory of Open Access Journals (Sweden)

    Mozhgan Bizhang

    Full Text Available The aim of this study was to determine the influence of manual toothbrushes with different bristle stiffness on the abrasivity on eroded and sound human dentin.Dentin specimens were made from impacted third molars and attributed to three groups: erosion-abrasion (EA, abrasion (A and erosion (E. The specimens from EA and E were treated with 1% citric acid (pH 2.3 for 1 min rinsed, and neutralized with artificial saliva for 15 min. This cycle was repeated five times. Thereafter, specimens from EA and A were treated with three toothbrushes types with different bristle stiffness (soft, medium, and hard in a custom-made toothbrushing machine. The brushing was performed at a load of 3 N with a toothpaste slurry for 630 s. This procedure was repeated five times, in group EA after each erosion cycle. EA and A groups passed through five cycles with a total of 6300 strokes. The abrasivity was analyzed by contact-free profilometry. Kruskal-Wallis and Mann-Whitney U tests were performed for statistical analysis.With respect to bristle stiffness there was no statistically significant difference in dentin loss within the EA group. In group A, a statistically significantly higher dentin loss was found for the soft in comparison to the hard bristles. No statistically significant differences were measured between soft/medium and medium/hard toothbrushes. The amount of dentin loss from specimens in the EA group was significantly higher than in the A group.Within the limitations of this study, the dentin loss in the Abrasion group was higher with soft bristles than with hard ones. This result might have an influence on the toothbrush recommendations for patients with non-carious cervical lesions.

  6. Topography reconstruction of eroding landscapes - A case study from a hummocky ground moraine (CarboZALF-D)

    Science.gov (United States)

    van der Meij, W. M.; Temme, A. J. A. M.; Wallinga, J.; Hierold, W.; Sommer, M.

    2017-10-01

    Erosion processes, aggravated by human activity, have a large impact on the spatial variation of soil and topographic properties. Knowledge of the topography prior to human-induced erosion (paleotopography) in naturally stable landscapes is valuable for identifying vulnerable landscape positions and is required as starting point for erosion modelling exercises. However, developing accurate reconstructions of paleotopography provide a major challenge for geomorphologists. Here, we present a set of paleotopographies for a closed kettle hole catchment in north-east Germany (4 ha), obtained through different reconstruction approaches. Current soil and colluvium thickness, estimated from a dataset of 264 soil descriptions using Ordinary Kriging, were used as input for a mass balance, or were compared with a set of undisturbed soil thicknesses to estimate the amount of erosion. The performance of the different approaches was assessed with cross-validation and the count of mispredicted eroded, depositional or stable landscape positions. The paleotopographic reconstruction approach based on the average thickness of undisturbed soils in the study area showed the best performance. This thickness (1.00 m) is comparable to the average undisturbed soil thickness in the region and in line with global correlations of soil thickness as a function of rainfall and initial CaCO3 content. The performance of the different approaches depended more on mispredictions of landscape position due to the assumption of a spatially constant initial soil depth than on small variations in this depth. To conclude, we mention several methodological and practical points of attention for future topography reconstruction studies, concerning data quality and availability, spatial configuration of data and other processes affecting topography.

  7. Assessment of soil erodibility indices for conservation reserve program lands in southwestern Kansas using satellite imagery and GIS techniques.

    Science.gov (United States)

    Park, Sunyurp; Egbert, Stephen L

    2005-12-01

    The soil erodibility index (EI) of Conservation Reserve Program (CRP) lands, which was the major criterion for CRP enrollment, was assessed for six counties in southwestern Kansas using USGS seamless digital elevation model data and Geographical Informational System techniques. The proportion of land areas with EI values of 8 or lower was less than 1% of the entire study area and most of the land areas (72.5%) were concentrated on EI values between 8 and 24. Although land acreage with EI values of 24 or higher decreased dramatically, the proportion of CRP lands to the other land-use types did not change much from low to high EI levels. The soil EI and physical soil characteristics of the CRP lands were compared to those of other land-use types. In general, the mean EI values of the land-use types were strongly correlated with physical soil properties, including organic matter content, clay content, available water capacity, permeability, and texture. CRP lands were compared in detail with cropland in terms of their soil characteristics to infer the pivotal cause of the land transformation. Although there was no significant statistical difference in EI between cropland and CRP soils, soil texture, soil family, and permeability were statistically different between the two. Statistical analyses of these three variables showed that CRP soils had coarser texture and higher permeability on average than cropland soils, indicating that CRP lands in the study area are drier than cropland soils. Therefore, soil moisture characteristics, not necessarily soil erosion potential, might have been the key factor for CRP enrollment in the study area.

  8. Cell invasion through basement membrane

    OpenAIRE

    Morrissey, Meghan A; Hagedorn, Elliott J; Sherwood, David R

    2013-01-01

    Cell invasion through basement membrane is an essential part of normal development and physiology, and occurs during the pathological progression of human inflammatory diseases and cancer. F-actin-rich membrane protrusions, called invadopodia, have been hypothesized to be the “drill bits” of invasive cells, mediating invasion through the dense, highly cross-linked basement membrane matrix. Though studied in vitro for over 30 y, invadopodia function in vivo has remained elusive. We have recent...

  9. Impact of leachate on groundwater pollution due to non-engineered municipal solid waste landfill sites of erode city, Tamil Nadu, India

    OpenAIRE

    Nagarajan, Rajkumar; Thirumalaisamy, Subramani; Lakshumanan, Elango

    2012-01-01

    Abstract Leachate and groundwater samples were collected from Vendipalayam, Semur and Vairapalayam landfill sites in Erode city, Tamil Nadu, India, to study the possible impact of leachate percolation on groundwater quality. Concentrations of various physicochemical parameters including heavy metals (Cd, Cr, Cu, Fe, Ni, Pb, Fe and Zn) were determined in leachate samples and are reported. The concentrations of Cl-, NO3-, SO42-, NH4+ were found to be in considerable levels in the groundwater sa...

  10. A Study on Employee Perception Towards Effectiveness And Impact Of Environment Management System At Tamil Nadu Cooperative Textile Processing Mill Ltd., Erode

    OpenAIRE

    Kannan,, K; Panimalar, M

    2013-01-01

    The study attempt to investigate on An Employee Perception towards Effectiveness and impact of Environment Management System is the process of system of procedures, training, and methods to monitor an organizations impact on the environment and evaluate ways to minimize negative impacts on the environment.This study was conducted at the Tamilnadu textile processing mill society Ltd, erode This environment management system bring the environment clean and protective, it helps organizations tak...

  11. Proposição de modelos para estimativa da erodibilidade de latossolos brasileiros Proposition of models for erodibility estimation of brazilian oxisols

    Directory of Open Access Journals (Sweden)

    Marx Leandro Naves Silva

    1999-12-01

    Full Text Available Os métodos existentes para determinação indireta da erodibilidade não têm se mostrado adequados quando aplicados aos solos tropicais, particularmente no tocante aos latossolos brasileiros. Sendo assim, objetivou-se, com este estudo, desenvolver modelos para a estimativa da erodibilidade desse grupamento de solos, a partir de variáveis morfológicas, físicas, químicas e mineralógicas do solo. Foram feitas em 19 latossolos das várias regiões geográficas brasileiras, 129 determinações (variáveis independentes, cujos resultados foram submetidos à análise de regressão linear múltipla em "backward" utilizando o programa SAS, relacionando-se com a erodibilidade obtida diretamente no campo através de parcelas de perdas de solo (variável dependente. Foi possível desenvolver cinco modelos, com graus crescentes de complexidade e precisão para a estimativa da erodibilidade dos latossolos brasileiros, englobando 37 determinações que apresentam significância.The existent methods for indirect determination of erodibility have not been adequate when applied to tropical soils, mainly in relation to Brazilian (Oxisols. So, this study aimed to develop models for determination of erodibility of this soils group, from morphological, physical, chemical and mineralogical variables of the soil. In this way, using 19 latosols from the various Brazilian geographical regions, 129 determinations (independent variables were made, whose results were submitted to multiple linear regression analyses in backward using the SAS program, correlating them with the erodibility directly obtained in the field through soil losses plots (dependent variable. It was possible to develop five models, with increasing degrees of complexity and precision, for the estimation of the erodibility of Brazilian latosols, involving 37 determinations that presented significance.

  12. Conspecific flowers of Sinapis arvensis are stronger competitors for pollinators than those of the invasive weed Bunias orientalis

    Science.gov (United States)

    Hochkirch, Axel; Mertes, Tamara; Rautenberg, Julia

    2012-03-01

    Biological invasions can affect the structure and function of ecosystems and threaten native plant species. Since most weeds rely on mutualistic relationships in their new environment, they may act as new competitors for pollinators. Pollinator competition is likely to be density dependent, but it is often difficult to disentangle competition caused by flower quality from effects caused by flower quantity. In order to test the effects of the presence and number of flowers of the invasive weed Bunias orientalis on the insect visitation rates in a native species ( Sinapis arvensis), we performed two replacement experiments using plants with standardised flower numbers. The visitation rates in S. arvensis were significantly higher than in B. orientalis and the number of insect visits dropped significantly with increasing density of S. arvensis flowers. These results suggest that intraspecific competition among flowers of S. arvensis is stronger than the competitive effect of alien flowers. As flowers of B. orientalis do not seem to distract visitors from S. arvensis, it is unlikely that pollinator competition between these two plant species plays a crucial role. However, it cannot be excluded that mass blossom stands of B. orientalis may distract flower visitors from native species.

  13. 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.

  14. Invasive v. non-invasive blood pressure measurements the ...

    African Journals Online (AJOL)

    A reasonable correlation exists between invasive and noninvasive methods of measuring systemic blood pressure. However, there are frequent individual differences between these methods and these variations have often caused the validity of the non-invasive measurement to be questioned. The hypothesis that certain ...

  15. 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

  16. 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...

  17. 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.

  18. Microbial ecology of biological invasions

    NARCIS (Netherlands)

    Putten, van der 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

  19. Prioritizing invasive plant management strategies

    Science.gov (United States)

    Invasive plants are seriously impacting rangelands by displacing desirable species. Management of these species is expensive and careful allocation of scarce dollars is necessary. Ecologically-based invasive plant management (EBIPM) has the potential to provide an improved decision-making process ...

  20. Cell invasion through basement membrane

    Science.gov (United States)

    Morrissey, Meghan A; Hagedorn, Elliott J; Sherwood, David R

    2013-01-01

    Cell invasion through basement membrane is an essential part of normal development and physiology, and occurs during the pathological progression of human inflammatory diseases and cancer. F-actin-rich membrane protrusions, called invadopodia, have been hypothesized to be the “drill bits” of invasive cells, mediating invasion through the dense, highly cross-linked basement membrane matrix. Though studied in vitro for over 30 y, invadopodia function in vivo has remained elusive. We have recently discovered that invadopodia breach basement membrane during anchor cell invasion in C. elegans, a genetically and visually tractable in vivo invasion event. Further, we found that the netrin receptor DCC localizes to the initial site of basement membrane breach and directs invasion through a single gap in the matrix. In this commentary, we examine how the dynamics and structure of AC-invadopodia compare with in vitro invadopodia and how the netrin receptor guides invasion through a single basement membrane breach. We end with a discussion of our surprising result that the anchor cell pushes the basement membrane aside, instead of completely dissolving it through proteolysis, and provide some ideas for how proteases and physical displacement may work together to ensure efficient and robust invasion. PMID:24778942

  1. Interstitial guidance of cancer invasion.

    NARCIS (Netherlands)

    Gritsenko, P.G.; Ilina, O.; Friedl, P.H.

    2012-01-01

    Cancer cell invasion into healthy tissues develops preferentially along pre-existing tracks of least resistance, followed by secondary tissue remodelling and destruction. The tissue scaffolds supporting or preventing guidance of invasion vary in structure and molecular composition between organs. In

  2. Earthworm invasions in the tropics

    Science.gov (United States)

    Grizelle Gonzalez; Ching Yu Huang; Xiaoming Zou; Carlos Rodriguez

    2006-01-01

    The effects and implications of invasive species in belowground terrestrial ecosystems are not well known in comparison with aboveground terrestrial and marine environments. The study of earthworm invasions in the tropics is limited by a lack of taxonomic knowledge and the potential for loss of species in native habitats due to anthropogenic land use change. Alteration...

  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. Invasive meningococcal disease

    Directory of Open Access Journals (Sweden)

    Vanessa L. Strelow

    2013-09-01

    Full Text Available Invasive meningococcal disease (IMD is a major public health and continues to cause substantial mortality and morbidity. Serotype C is the most frequent in Brazil. The clinical spectrum of IMD is broad (meningitis, meningococcemia or both and the clinical evolution may be unpredictable. Main features associated with mortality are: age higher than 50 years old, seizures, shock, and meningococcemia without meningitis. Blood cultures should be obtained immediately. Lumbar puncture can be performed without previous computed tomography scan (CT in most cases. Clinical features can be useful to predic patients where an abnormal CT scan is likely. Cerebrospinal fluid (CSF culture and Gram stain should always be required. Latex agglutination sensitivity is highly variable. Polymerase chain reaction is specially useful when other methods are negative or delayed. Usually ceftriaxone should not be delayed while awaiting CSF study or CT. Dexamethasone can be used in meningococcal meningitis. Early suspicion of IMD and antibiotic in primary care before hospitalization, rapid transportation to a hospital, and stabilization in an intensive-care unit has substantially reduced the case-fatality rate. Vaccines against serotypes A, C, W-135, and Y are available while vaccines against serotype B are expected.

  5. 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.

  6. Life-size experimentation of bioengineering for sedimentation control in eroded marly gullies (Francon catchment, Draix, France)

    Science.gov (United States)

    Rey, F.; Labonne, S.; Mathys, N.; Puëch, C.; Jardin, J. L.

    2009-04-01

    On marly eroded terrains of the French Southern Alps, many researches are undertaken in order to better understand the role of vegetation and bioengineering works on erosion and sedimentation control. These researches in particular made it possible to develop tools of ecological engineering bound for the practitioners in order to conceive operations for mitigation of damage related to soil erosion. In particular they are methods of diagnosis and strategies for action with bioengineering techniques. These tools must make it possible to guide the choice of the gullies to be rehabilitated and that of the types of works of vegetalisation to be used, in particular via the establishment and the use of a gully typology. Before passing to phases of real use of these tools through expertise, as this is today considered on the scale of the large catchment area of the Durance in France (4000 km²), it appeared convenient to carry out a life-size test of application of these tools. This test was carried out on the marly catchment of Francon (73 ha), which belongs to the experimental complex of Draix (04), labellized Observatoire of Research in Environment (ORE) and of which the objectives are to improve knowledge on the formation of floods and bedload transport in small mountainous marly catchments. On this basin, 30 gullies, representing a total surface area of approximately 20 ha, were thus identified like "ecologically suitable for rehabilitation", i.e. on which it appeared possible and convenient to install bioengineering works. This test thus made it possible to check the relevance of the tools proposed to apply an action with bioengineering. An ecological operation of rehabilitation of this basin, carried out jointly with the French ‘Office National des Forêts (ONF)', was then carried out in April 2008 in accordance with the test results. It consisted of the construction of 672 bioengineering works, namely of "brush layers and brush mats of cuttings on deadwood

  7. Effects of in ovo 2,3,7,8-TCDD exposure on hepatic ethoxyresorufin O-deethylase (EROD) induction and growth-related parameters in avian species

    Energy Technology Data Exchange (ETDEWEB)

    Janz, D.M.; Bellward, G.D. [Univ. of British Columbia, Vancouver, British Columbia (Canada). Faculty of Pharmaceutical Sciences

    1994-12-31

    The effects of early in ovo TCDD exposure on CYP1A1 induction and indices of growth were determined in domestic chicken (Gallus gallus) and pigeon (Columba livia) hatchlings. TCDD (in corn oil) was injected into the air sac of eggs on embryonic day 4 (E4) (chickens, 0.1 {mu}g/kg egg; pigeons, 1.0 {mu}g/kg egg), and on E14 (pigeons, 3.0 {mu}g/kg egg). In chickens, hepatic EROD was induced 13, 15, 34, and 43-fold above control activities on E19, day of hatch (DO), day 2 after hatch (D2), and D4, respectively. Plasma thyroid hormone (T{sub 3} T{sub 4}) concentrations, which are known to peak during the perinatal period in chickens, were not affected by TCDD treatment when measured on E17, E19, D0, D2, and D4. In pigeons injected on E4, EROD was induced 15 and 6-fold on D0 and D7, respectively. There were significant decreases in yolk-free body weight, crown-rump, tibia, culmen, and wing lengths, and an elevated liver to body weight ratio (LSI) in TCDD-treated pigeons raised to D7 (p < 0.01). In pigeons injected on E14 (3{mu}g/kg), EROD was induced 14 and 10-fold on D0 and D7, respectively. Crown-rump and culmen lengths were decreased (p < 0.05) and LSI was increased (p < 0.01) on D0. There were significant decreases in all morphological parameters, and an increased LSI on D7 (p < 0.01) in TCDD-treated birds. These techniques will be used in further studies to investigate possible mechanisms of TCDD embryotoxicity in wild avian species, such as the great blue heron (Ardea herodias).

  8. 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

  9. 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

  10. 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...

  11. Cheatgrass invasion and wildlife habitat

    Science.gov (United States)

    The introduction and subsequent invasion of cheatgrass (Bromus tectorum) has altered native plant communities and the wildlife species that depend on these communities. Cheatgrass has truncated secondary succession by outcompeting native plant species for limited resources, thus building persistent...

  12. 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.

  13. Non-Invasive Prenatal Testing

    OpenAIRE

    Ekici, Cemal

    2015-01-01

    The rate of newborns with trisomy 21 (Down syndrome) who have been referred to our pediatric newborn clinic is very high. This shows that prenatal screening in the region is not carried out well. Prenatal diagnosis and screening methods include invasive prenatal diagnosis methods (amniocentesis, chorionic villus sampling (CVS), and cordocentesis) and non-invasive prenatal diagnosis (NIPT) which cell free fetal DNA (cffDNA) screening of maternal blood samples. After the discovery of the signs ...

  14. Non-Invasive Prenatal Testing

    OpenAIRE

    McGillivray, Barbara C.

    1988-01-01

    The rate of newborns with trisomy 21 (Down syndrome) who have been referred to our pediatric newborn clinic is very high. This shows that prenatal screening in the region is not carried out well. Prenatal diagnosis and screening methods include invasive prenatal diagnosis methods (amniocentesis, chorionic villus sampling (CVS), and cordocentesis) and non-invasive prenatal diagnosis (NIPT) which cell free fetal DNA (cffDNA) screening of maternal blood samples. After the discovery of the signs ...

  15. 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

  16. 75 FR 69698 - Invasive Species Advisory Committee

    Science.gov (United States)

    2010-11-15

    ... DEPARTMENT OF THE INTERIOR Office of the Secretary Invasive Species Advisory Committee AGENCY: Office of the Secretary, Interior. ACTION: Notice of public meetings of the Invasive Species Advisory... of meetings of the Invasive Species Advisory Committee (ISAC). Comprised of 30 nonfederal invasive...

  17. 76 FR 68776 - Invasive Species Advisory Committee

    Science.gov (United States)

    2011-11-07

    ... DEPARTMENT OF THE INTERIOR Office of the Secretary Invasive Species Advisory Committee AGENCY: Office of the Secretary, Interior. ACTION: Notice of public meetings of the Invasive Species Advisory... of meetings of the Invasive Species Advisory Committee (ISAC). Comprised of 29 nonfederal invasive...

  18. 77 FR 23740 - Invasive Species Advisory Committee

    Science.gov (United States)

    2012-04-20

    ... DEPARTMENT OF THE INTERIOR Office of the Secretary Invasive Species Advisory Committee AGENCY: Office of the Secretary, Interior. ACTION: Notice of Public Meetings of the Invasive Species Advisory... of meetings of the Invasive Species Advisory Committee (ISAC). Comprised of 30 nonfederal invasive...

  19. Estimativa da erodibilidade em entressulcos de latossolos do Rio Grande do Sul Prediction of interrill soil erodibility of oxisols in Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Maria Cândida Moitinho Nunes

    2008-12-01

    oxalato amônio ácido (Fe o, explicaram 97 % (p Models of soil water erosion prediction and estimation are generally based on a series of parameters, normally determined by applying simulated rainfall in the field or laboratory. The use of simpler, faster and cheaper parameters such as texture, content and oxide type and aggregate water stability may contribute to facilitate the estimation of the factor interrill soil erodibility (Ki. The purpose of this study was: i to determine the interrill soil erodibility of three Brazilian Oxisols; ii evaluate the use of soil sand and clay contents in the prediction of interrill soil erodibility, as in the WEPP model; iii verify the correlation among some soil properties and the interrill soil erodibility factor. The interrill soil erosion rates were determined in laboratory, using three Oxisols with different clay content of the State of Rio Grande do Sul, Brazil, under a mean intensity of simulated rainfall of 88 mm h-1, applied during 180 min on bare soil, using experimental interrill plots of 0.36 m² at a slope of 0.09 m m-1 and an initial water tension of 6 kPa. The susceptibility of soils with high clay and Fe oxide contents and higher water aggregate stability to interrill erosion was lower. The experimentally determined values of interrill soil erodibility (Ki factor varied from 0.76 x 10(6 kg s m-4 to 1.48 x10(6 kg s m-4 for the studied Oxisols. The aggregate water stability index was highly correlated with the interrill soil erodibility factor (r= -0.90**. The use of soil sand and clay contents, as suggested by the WEPP model, did not prove adequate to estimate the interrill soil erodibility (Ki factor. The variation in clay and Fe oxide contents explained 97 % (p<0.01 of the interrill soil erodibility variation.

  20. DNA damage, EROD activity, condition indices, and their linkages with contaminants in female flounder (Platichthys flesus) from the southern Baltic Sea.

    Science.gov (United States)

    Dabrowska, Henryka; Kopko, Orest; Góra, Agnieszka; Waszak, Ilona; Walkusz-Miotk, Jolanta

    2014-10-15

    The Baltic Sea is considered as one of the marine areas most exposed to human impacts. A variety of chemical contaminants pose a threat to the habitants. Female flounder (Platichthys flesus) collected from three locations in the southern Baltic Sea in February 2010 were examined for biomarkers of exposure to genotoxic agents (DNA damage), AhR-active contaminants (ethoxyresorufin-O-deethylase, EROD activity), and somatic condition indexes. Organochlorine contaminants (OCs) and polycyclic aromatic hydrocarbon (PAH) metabolites were also measured in individual flounder to evaluate the biological responses in the context of contaminant burden. The genotoxicity, mildly exceeding a background level, revealed a significant relationship with mono-ortho substituted PCB (m-oPCB). Hepatic EROD activity was highly induced, yet showed no association with any of the contaminants measured other than biliary 1-OH pyrene normalized to pigment absorbance. Significant negative relationships were observed for lipid-based OCs and the gonado-somatic index (GSI) as well as for Ʃm-oPCB concentrations and the condition factor (CF). Principal component analysis (PCA) revealed an overall connection between somatic condition indexes, biomarkers, and chemical variables. Of the three locations, flounder inhabiting the Gulf of Gdańsk had the greatest contaminant burden and appeared to be the most affected. Of great concern is the reduced GSI in this location which can be attributed to the effects of contaminants and warrants further investigation. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Impact of leachate on groundwater pollution due to non-engineered municipal solid waste landfill sites of erode city, Tamil Nadu, India

    Directory of Open Access Journals (Sweden)

    Nagarajan Rajkumar

    2012-12-01

    Full Text Available Abstract Leachate and groundwater samples were collected from Vendipalayam, Semur and Vairapalayam landfill sites in Erode city, Tamil Nadu, India, to study the possible impact of leachate percolation on groundwater quality. Concentrations of various physicochemical parameters including heavy metals (Cd, Cr, Cu, Fe, Ni, Pb, Fe and Zn were determined in leachate samples and are reported. The concentrations of Cl-, NO3-, SO42-, NH4+ were found to be in considerable levels in the groundwater samples particularly near to the landfill sites, likely indicating that groundwater quality is being significantly affected by leachate percolation. Further they were proved to be the tracers for groundwater contamination near Semur and Vendipalayam dumpyards. The presence of contaminants in groundwater particularly near the landfill sites warns its quality and thus renders the associated aquifer unreliable for domestic water supply and other uses. Although some remedial measures are suggested to reduce further groundwater contamination via leachate percolation, the present study demands for the proper management of waste in Erode city.

  2. Invasive amphibians in southern Africa: A review of invasion pathways

    Directory of Open Access Journals (Sweden)

    John Measey

    2017-03-01

    Full Text Available Background: Globally, invasive amphibians are known for their environmental and social impacts that range from poisoning of local fauna and human populations to direct predation on other amphibians. Although several countries on most continents have had multiple introductions of many species, southern Africa appears to have escaped allochthonous introductions. Instead, it has a small number of domestic exotic species that have rapidly expanded their ranges and established invasive populations within South Africa. Objectives & methods: We used the literature to provide a historical overview of dispersal by some of the world’s major invasive amphibians, give examples of species that are commonly moved as stowaways and discuss historical and current amphibian trade in the region. In addition, we give an overview of new South African legislation and how this is applied to amphibian invasions, as well as providing updates on the introduced populations of three domestic exotics: Hyperolius marmoratus, Sclerophrys gutturalis and Xenopus laevis. Results: We show that frogs are mainly moved around southern Africa through ‘jump’ dispersal, although there are a number of records of ‘cultivation’, ‘leading-edge’ and ‘extreme long-distance’ dispersal types. Important pathways include trade in fruit and vegetables, horticultural products and shipping containers. Conclusion: We suggest that southern Africa is becoming more vulnerable to amphibian invasions because of an increase in trade, agricultural and domestic impoundments as well as global climate change. Increasing propagule pressure suggests that preventing new introductions will become a key challenge for the future. Currently, trade in amphibians in the region is practically non-existent, suggesting potential for best practice to prevent importation of species with high invasion potential and to stop the spread of disease.

  3. Anesthesia for minimally invasive neurosurgery.

    Science.gov (United States)

    Prabhakar, Hemanshu; Mahajan, Charu; Kapoor, Indu

    2017-10-01

    With an ultimate aim of improving patients overall outcome and satisfaction, minimally invasive surgical approach is becoming more of a norm. The related anesthetic evidence has not expanded at the same rate as surgical and technological advancement. This article reviews the recent evidence on anesthesia and perioperative concerns for patients undergoing minimally invasive neurosurgery. Minimally invasive cranial and spinal surgeries have been made possible only by vast technological development. Points of surgical interest can be precisely located with the help of stereotaxy and neuronavigation and special endoscopes which decrease the tissue trauma. The principles of neuroanethesia remain the same, but few concerns are specific for each technique. Dexmedetomidine has a favorable profile for procedures carried out under sedation technique. As the new surgical techniques are coming up, lesser known anesthetic concerns may also come into light. Over the last year, little new information has been added to existing literature regarding anesthesia for minimally invasive neurosurgeries. Neuroanesthesia goals remain the same and less invasive surgical techniques do not translate into safe anesthesia. Specific concerns for each procedure should be taken into consideration.

  4. Interstitial guidance of cancer invasion.

    Science.gov (United States)

    Gritsenko, Pavlo G; Ilina, Olga; Friedl, Peter

    2012-01-01

    Cancer cell invasion into healthy tissues develops preferentially along pre-existing tracks of least resistance, followed by secondary tissue remodelling and destruction. The tissue scaffolds supporting or preventing guidance of invasion vary in structure and molecular composition between organs. In the brain, the guidance is provided by myelinated axons, astrocyte processes, and blood vessels which are used as invasion routes by glioma cells. In the human breast, containing interstitial collagen-rich connective tissue, disseminating breast cancer cells preferentially invade along bundled collagen fibrils and the surface of adipocytes. In both invasion types, physical guidance prompted by interfaces and space is complemented by molecular guidance. Generic mechanisms shared by most, if not all, tissues include (i) guidance by integrins towards fibrillar interstitial collagen and/or laminins and type IV collagen in basement membranes decorating vessels and adipocytes, and, likely, CD44 engaging with hyaluronan; (ii) haptotactic guidance by chemokines and growth factors; and likely (iii) physical pushing mechanisms. Tissue-specific, resticted guidance cues include ECM proteins with restricted expression (tenascins, lecticans), cell-cell interfaces, and newly secreted matrix molecules decorating ECM fibres (laminin-332, thrombospondin-1, osteopontin, periostin). We here review physical and molecular guidance mechanisms in interstitial tissue and brain parenchyma and explore shared principles and organ-specific differences, and their implications for experimental model design and therapeutic targeting of tumour cell invasion. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

  5. Optic nerve invasion of uveal melanoma

    DEFF Research Database (Denmark)

    Lindegaard, Jens; Isager, Peter; Prause, Jan Ulrik

    2007-01-01

    The aim of the study was to identify the histopathological characteristics associated with the invasion of the optic nerve of uveal melanoma and to evaluate the association between invasion of the optic nerve and survival. In order to achieve this, all uveal melanomas with optic nerve invasion...... 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...... invasion. Prelaminar/laminar optic nerve invasion was in multivariate analysis associated with focal retinal invasion, neovascularization of the chamber angle, and scleral invasion. Postlaminar invasion was further associated with non-spindle cell type and rupture of the inner limiting membrane...

  6. Invasive exotic plants suffer less herbivory than non-invasive exotic plants

    OpenAIRE

    Cappuccino, Naomi; Carpenter, David

    2005-01-01

    We surveyed naturally occurring leaf herbivory in nine invasive and nine non-invasive exotic plant species sampled in natural areas in Ontario, New York and Massachusetts, and found that invasive plants experienced, on average, 96% less leaf damage than non-invasive species. Invasive plants were also more taxonomically isolated than non-invasive plants, belonging to families with 75% fewer native North American genera. However, the relationship between taxonomic isolation at the family level ...

  7. 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

  8. 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

  9. 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.

  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. Non-invasive mechanical ventilation

    African Journals Online (AJOL)

    Nicky

    failure may benefit from a trial of NIV. Increased work of breathing, as noted by use of accessory breathing. SAJCC. 10. July 2005, V ol. 21, No. 1. University of Manitoba and Manitoba Institute of Child Health, Winnipeg, Canada. B Louise Giles, MD, FRCPC. Non-invasive ventilation (NIV) is a modality of providing airway and ...

  12. 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

  13. 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.

  14. 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...

  15. 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.

  16. 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.

  17. Approaching invasive species in Madagascar | Kull | Madagascar ...

    African Journals Online (AJOL)

    invasive', the topic of invasive species has until recently received less attention here than in other island contexts. Some species, often alien to Madagascar and introduced by humans, have expanded their range rapidly and have had both ...

  18. Invasive thymoma: CT diagnosis and evaluation

    International Nuclear Information System (INIS)

    Sun Zhonghua; Yu Hong; Liu Hengshun; Yan Hongzhen; Zhang Shurong

    1998-01-01

    Purpose: To study the CT manifestation of invasive thymoma for staging and treatment planning. Materials and methods: The authors reviewed and analyzed the CT scans of 26 patients with invasive thymoma confirmed by surgery and pathology with emphasis on lesion density, invasion of adjacent mediastinal structures, pleural seeding mediastinal nodes and extra-mediastinal metastases. Results: In 26 cases of invasive thymoma, all CT scans demonstrated the soft tissue mass in anterior mediastinum, with heterogeneous density in 16 patients. Irregular invasion to adjacent organs was found in 24 patients. The main findings were mediastinal pleura invasion in 7, lung invasion 9, pleural implants 3, cardiovascular involvement in 20, and cardiophrenic and abdominal invasion in 3. CT is especially effective in detecting the involvement of pleura, pericardium and lung. Conclusion: Computed tomography provides the most reliable assessment of the extent of the disease. Conventional CT scan allows accurate staging and treatment planning

  19. 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...

  20. 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...

  1. Invasive Species Science Update (No. 9)

    Science.gov (United States)

    Justin Runyon

    2017-01-01

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

  2. 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...

  3. 78 FR 70317 - Invasive Species Advisory Committee

    Science.gov (United States)

    2013-11-25

    ... DEPARTMENT OF THE INTERIOR Office of the Secretary Invasive Species Advisory Committee AGENCY..., notice is hereby given of meetings of the Invasive Species Advisory Committee. The purpose of the Advisory Committee is to provide advice to the National Invasive Species Council, as authorized by...

  4. Invasive species and climate change (Chapter 7)

    Science.gov (United States)

    Justin B. Runyon; Jack L. Butler; Megan M. Friggens; Susan E. Meyer; Sharlene E. Sing

    2012-01-01

    Invasive species present one of the greatest threats to the health and sustainability of ecosystems worldwide. Invasive plants, animals, and diseases are known to have significant negative effects on biological diversity and the ecological structure and functions of native ecosystems. Moreover, the economic cost imposed by invasive species is enormous—the damage...

  5. Invasive Species Science Update (No. 4)

    Science.gov (United States)

    Ned B. Klopfenstein; Brian W. Geils

    2010-01-01

    The fourth issue of Invasive Species Science Update has finally arrived. This newsletter has no set publication schedule, but our intent is to deliver invasive species information on a timely basis. The RMRS Invasive Species Working Group (ISWG) has been reorganized and recharged. General information on the ISWG is presented in a publication by Butler and others (2009...

  6. 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...

  7. Invasive Species Science Update (No. 5)

    Science.gov (United States)

    Dean Pearson; Yvette Ortega

    2011-01-01

    Welcome to the fifth issue of the Rocky Mountain Research Station's (RMRS) Invasive Species Science Update. The newsletter is produced by the RMRS Invasive Species Working Group (ISWG), which is a core group of scientists who volunteer to coordinate outreach of RMRS invasive species science to managers and the public. After publishing the past four newsletters, we...

  8. 78 FR 11899 - Invasive Species Advisory Committee

    Science.gov (United States)

    2013-02-20

    ... DEPARTMENT OF THE INTERIOR Office of the Secretary Invasive Species Advisory Committee AGENCY... notice of public meetings of the Invasive Species Advisory Committee. The document contained incorrect..., March 6, 2013; 9 a.m. to 1:45 p.m. Meeting of the Invasive Species Advisory Committee (OPEN): Thursday...

  9. Invasive Species Science Update (No. 8)

    Science.gov (United States)

    Dean Pearson; Yvette Ortega; Jack Butler

    2015-01-01

    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...

  10. 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...

  11. 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.

  12. Invasive procedures with questionable indications

    Directory of Open Access Journals (Sweden)

    Sergei V. Jargin

    2014-12-01

    Full Text Available Insufficient coordination of medical research and partial isolation from the international scientific community can result in application of invasive methods without sufficient indications. Here is presented an overview of renal and pancreatic biopsy studies performed in the course of the operations of pancreatic blood shunting into the systemic blood flow in type 1 diabetic patients. Furthermore a surgical procedure of lung denervation as a treatment method of asthma as well as the use of bronchoscopy for research in asthmatics are discussed here. Today, the upturn in Russian economy enables acquisition of modern equipment; and medical research is on the increase. Under these circumstances, the purpose of this letter was to remind that, performing surgical or other invasive procedures, the risk-to-benefit ratio should be kept as low as possible.

  13. 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

  14. Non-invasive extending prosthesis

    OpenAIRE

    Meswania, Jayantilal Mohanlal

    2006-01-01

    Most sarcomas of the bone occur in patients of a relatively young age including skeletally immature patients. Approximately 50 child sarcomas are treated with limb salvage surgery per year in the United Kingdom. These children need an extendible implant that can be lengthened periodically to keep pace with the growth in the opposite limb. Surgically, invasive devices have been used for the past thirty years with intrinsic problems of infection and long-term recurrent trauma to the patient. To...

  15. 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.

  16. 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.; Nystrom, Magnus; Sendzimir, Jan; Hopton, Matthew E.; Kolasa, Jurek; Allen, Craig R.

    2016-01-01

    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.

  17. 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.

  18. Will climate change promote future invasions?

    Science.gov (United States)

    Bellard, Celine; Thuiller, Wilfried; Leroy, Boris; Genovesi, Piero; Bakkenes, Michel; Courchamp, Franck

    2013-12-01

    Biological invasion is increasingly recognized as one of the greatest threats to biodiversity. Using ensemble forecasts from species distribution models to project future suitable areas of the 100 of the world's worst invasive species defined by the International Union for the Conservation of Nature, we show that both climate and land use changes will likely cause drastic species range shifts. Looking at potential spatial aggregation of invasive species, we identify three future hotspots of invasion in Europe, northeastern North America, and Oceania. We also emphasize that some regions could lose a significant number of invasive alien species, creating opportunities for ecosystem restoration. From the list of 100, scenarios of potential range distributions show a consistent shrinking for invasive amphibians and birds, while for aquatic and terrestrial invertebrates distributions are projected to substantially increase in most cases. Given the harmful impacts these invasive species currently have on ecosystems, these species will likely dramatically influence the future of biodiversity. © 2013 John Wiley & Sons Ltd.

  19. 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

  20. The valve of CT in diagnosing the invasive and non-invasive thymoma

    International Nuclear Information System (INIS)

    Tang Wenyan; Jiang Kuiming; Song Ting; Lin Wenjian; Chen Zhanhang

    2009-01-01

    Objective: To Study CT features of thymoma and its value in differentiating the invasive from non-invasive thymoma. Methods: CT findings of 17 cases with thymoma (11 non-invasive and 6 invasive) confirmed by surgery and pathology were analyzed retrospectively. Results: 11 cases were non-invasive thymoma. On CT, the tumors were round or oval in 6 cases, lobulate in 4 cases, and irregular in 1 case. The lesions showed homogeneous density and mild enhancement in 9 cases. 10 of them showed complete capsules without invasion. The mass-cardiovascular interface was: convex type in 5 cases, flat type in 3 cases and concave type in 2 cases. 6 cases were invasive thymoma, tumors were irregular and heterogeneous in 5 cases. Significant and inhomogeneous enhancement on post contrast CT was found. Conclusion: The CT features of thymoma was specific, and CT is of great value in differentiating the invasive from non-invasive thymoma. (authors)

  1. A subcontinental view of forest plant invasions

    Directory of Open Access Journals (Sweden)

    Christopher M. Oswalt

    2015-01-01

    Full Text Available Over the last few decades, considerable attention has focused on small-scale studies of invasive plants and invaded systems. Unfortunately, small scale studies rarely provide comprehensive insight into the complexities of biological invasions at macroscales. Systematic and repeated monitoring of biological invasions at broad scales are rare. In this report, we highlight a unique invasive plant database from the national Forest Inventory and Analysis (FIA program of the United States Forest Service. We demonstrate the importance and capability of this subcontinental-wide database by showcasing several critical macroscale invasion patterns that have emerged from its initial analysis: (1 large portion of the forests systems (39% in the United States are impacted by invasive plants, (2 forests in the eastern United States harbor more invasive species than the western regions, (3 human land-use legacies at regional to national scales may drive large-scale invasion patterns. This accumulated dataset, which continues to grow in temporal richness with repeated measurements, will allow the understanding of invasion patterns and processes at multi-spatial and temporal scales. Such insights are not possible from smaller-scale studies, illustrating the benefit that can be gained by investing in the development of regional to continental-wide invasion monitoring programs elsewhere.

  2. Secretome signature of invasive glioblastoma multiforme.

    Science.gov (United States)

    Formolo, Catherine A; Williams, Russell; Gordish-Dressman, Heather; MacDonald, Tobey J; Lee, Norman H; Hathout, Yetrib

    2011-07-01

    The incurability of malignant glioblastomas is mainly attributed to their highly invasive nature coupled with resistance to chemo- and radiation therapy. Because invasiveness is partially dictated by the proteins these tumors secrete we used SILAC to characterize the secretomes of four glioblastoma cell lines (LN18, T98, U118 and U87). Although U87 and U118 cells both secreted high levels of well-known invasion promoting proteins, a Matrigel invasion assay showed U87 cells to be eight times more invasive than U118 cells, suggesting that additional proteins secreted by U87 cells may contribute to the highly invasive phenotype. Indeed, we identified a number of proteins highly or exclusively expressed by U87 cells as compared to the less invasive cell lines. The most striking of these include ADAM9, ADAM10, cathepsin B, cathepsin L1, osteopontin, neuropilin-1, semaphorin-7A, suprabasin, and chitinase-3-like protein 1. U87 cells also expressed significantly low levels of some cell adhesion proteins such as periostin and EMILIN-1. Correlation of secretome profiles with relative levels of invasiveness using Pavlidis template matching further indicated potential roles for these proteins in U87 glioblastoma invasion. Antibody inhibition of CH3L1 reduced U87 cell invasiveness by 30%.

  3. 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.

  4. 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

  5. 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

  6. 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.

  7. [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.

  8. [Interactions between invasive plants and arbuscular mycorrhizal fungi: a review].

    Science.gov (United States)

    Bai, Yan-fang; Guo, Shao-xia; Li, Min

    2011-09-01

    The invasion of invasive plants changes the biological community structure in their invaded lands, leading to the biodiversity loss. As an important component of soil microorganisms in terrestrial ecosystem, arbuscular mycorrhizal (AM) fungi can affect the growth performance of invasive plants. This kind of specific relations between AM fungi and invasive plants also implies that AM fungi can affect plant invasion. On the other hand, the invasion of invasive plants can affect the community structure and function of AM fungi. This paper summarized the species and harms of invasive plants in China, and discussed the relationships between AM fungi and invasive plants invasion, including the roles of AM fungi in the processes of invasive plants invasion, the effects of the invasion on AM fungi, and the interactive mechanisms between the invasion and AM fungi.

  9. Invasive plants have broader physiological niches.

    Science.gov (United States)

    Higgins, Steven I; Richardson, David M

    2014-07-22

    Invasive species cost the global economy billions of dollars each year, but ecologists have struggled to predict the risk of an introduced species naturalizing and invading. Although carefully designed experiments are needed to fully elucidate what makes some species invasive, much can be learned from unintentional experiments involving the introduction of species beyond their native ranges. Here, we assess invasion risk by linking a physiologically based species distribution model with data on the invasive success of 749 Australian acacia and eucalypt tree species that have, over more than a century, been introduced around the world. The model correctly predicts 92% of occurrences observed outside of Australia from an independent dataset. We found that invasiveness is positively associated with the projection of physiological niche volume in geographic space, thereby illustrating that species tolerant of a broader range of environmental conditions are more likely to be invasive. Species achieve this broader tolerance in different ways, meaning that the traits that define invasive success are context-specific. Hence, our study reconciles studies that have failed to identify the traits that define invasive success with the urgent and pragmatic need to predict invasive success.

  10. Secretome Signature of Invasive Glioblastoma Multiforme

    OpenAIRE

    Formolo, Catherine A.; Williams, Russell; Gordish-Dressman, Heather; MacDonald, Tobey J.; Lee, Norman H.; Hathout, Yetrib

    2011-01-01

    The incurability of malignant glioblastomas is mainly attributed to their highly invasive nature coupled with resistance to chemo- and radiation therapy. Because invasiveness is partially dictated by the proteins these tumors secrete we used SILAC to characterize the secretomes of four glioblastoma cell lines (LN18, T98, U118 and U87). Although U87 and U118 cells both secreted high levels of well-known invasion promoting proteins, a Matrigel invasion assay showed U87 cells to be eight times m...

  11. 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...... in response to growth temperature. Populations of the submerged macrophyte Ceratophyllum demersum from New Zealand, where the species is introduced and invasive, and from Denmark, where the species is native and non-invasive, were grown in a common garden setup at temperatures of 12, 18, 25 and 35 ◦C. We...... 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...

  12. Comparison of the Invasion of Crete and the Proposed Invasion in Malta

    National Research Council Canada - National Science Library

    Kavanaugh, Stephen L

    2006-01-01

    .... The invasion of Crete was executed from 20 May to 1 June 1941 with heavy German losses. The invasion of Malta never took place even though the senior military leaders in the Oberkommando der Wehrmacht (OKW...

  13. 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

  14. Raja Gopal, Prof. Erode Subramanian

    Indian Academy of Sciences (India)

    ), D.Sc. (h.c.), FNA, FNASc. Date of birth: 12 May 1936. Specialization: Solid State Physics, Statistical Physics and Instrumentation Address: Emeritus Scientist, Department of Physics, Indian Institute of Science, Bengaluru 560 012, Karnataka

  15. 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.

  16. Alabama invasive plant council: list of invasive plants by cultural use categories

    Science.gov (United States)

    James H. Miller; Nancy J. Loewenstein; Curtis J. Hansen

    2006-01-01

    Shortly after formation of the Alabama Invasive Plant Council (ALIPC) in 2003, a committee dedicated to assessment and listing of invasive plants was convened – the ALIPC Invasive Plant Listing Committee. Committee members were drawn from the wide diversity of expertise of the Council, which welcomes participation by all land-use and water-use managers, owners,...

  17. 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 ...

  18. 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...

  19. Fungal Adaptations to Mutualistic Life with Ants

    DEFF Research Database (Denmark)

    Kooij, Pepijn Wilhelmus

    that forage on crude substrates such as insect frass and dry plant material, to large colonies of the leaf-cutting ants with several thousands to several million workers that provide live plant material to their fungus gardens. Leaf-cutting ants are the dominant herbivores of the Neo-tropics, and have a major...

  20. 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.

  1. 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

  2. From source to sink: Unravelling the complex in situ cosmogenic 10Be-14C signature in eroding bedrock surfaces and river sediment from the Bolivian Altiplano

    Science.gov (United States)

    Hippe, Kristina; Lupker, Maarten; Gordijn, Tiemen; Ivy-Ochs, Susan; Kober, Florian; Christl, Marcus; Wacker, Lukas; Hajdas, Irka; Wieler, Rainer

    2017-04-01

    Sediment storage is a critical component of fluvial sedimentary systems. By interrupting transport processes, intermittent sediment storage can effectively decouple source from sink and buffer the transmission of signals of environmental change (e.g., in climate, vegetation, human impact) through the fluvial system. Combined in situ cosmogenic 14C-10Be analysis in fluvial sediment provides a unique method to simultaneously assess sediment transit times (in situ 14C signal) and long-term sediment production rates from bedrock erosion (10Be signal). The key is the much shorter half-life of in situ 14C compared to 10Be which causes a rapid decrease of the in situ 14C concentration when sediment is buried during sediment storage and creates an offset to 10Be. Here, we use the in situ 14C-10Be chronometer to determine changes in surface erosion and estimate absolute rates of sediment transfer in a catchment on the Bolivian Altiplano. Previous research in the study area has found a significant offset in the in situ 14C-10Be inventories from river sediments with much lower in situ 14C concentrations than expected from the 10Be content for steady-state conditions. This offset has been interpreted to reflect sediment storage over the past 11-20 ka [1]. Additional analyses of in situ 14C and 10Be in a dense network of sediment samples from the main channel and tributaries agree with previous data and yield very low in situ 14C concentrations that suggest an increase in storage duration by a few ka with downstream distance. However, analyses of in situ 14C-10Be in hilltop samples from the eroding source area reveal an almost as large offset as in the river sediments. Such complex in situ 14C-10Be inventories in the source area have a severe impact on the quantification of sediment storage times and strongly challenge previous data interpretation. The most straightforward explanation for the in situ 14C-10Be offset at hilltop locations is a change in denudation rate during the

  3. Quantifying uranium transport rates and storage of fluvially eroded mine tailings from a historic mine site in the Grand Canyon Region

    Science.gov (United States)

    Skalak, K.; Benthem, A. J.; Walton-Day, K. E.; Jolly, G.

    2015-12-01

    The Grand Canyon region contains a large number of breccia pipes with economically viable uranium, copper, and silver concentrations. Mining in this region has occurred since the late 19th century and has produced ore and waste rock having elevated levels of uranium and other contaminants. Fluvial transport of these contaminants from mine sites is a possibility, as this arid region is susceptible to violent storms and flash flooding which might erode and mobilize ore or waste rock. In order to assess and manage the risks associated with uranium mining, it is important to understand the transport and storage rates of sediment and uranium within the ephemeral streams of this region. We are developing a 1-dimensional sediment transportation model to examine uranium transport and storage through a typical canyon system in this region. Our study site is Hack Canyon Mine, a uranium and copper mine site, which operated in the 1980's and is currently experiencing fluvial erosion of its waste rock repository. The mine is located approximately 40km upstream from the Colorado River and is in a deep, narrow canyon with a small watershed. The stream is ephemeral for the upper half of its length and sediment is primarily mobilized during flash flood events. We collected sediment samples at 110 locations longitudinally through the river system to examine the distribution of uranium in the stream. Samples were sieved to the sand size and below fraction (uranium was measured by gamma-ray spectroscopy. Sediment storage zones were also examined in the upper 8km of the system to determine where uranium is preferentially stored in canyon systems. This information will quantify the downstream transport of constituents associated with the Hack Canyon waste rock and contribute to understanding the risks associated with fluvial mobilization of uranium mine waste.

  4. 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.

  5. 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.

  6. Benefits of non invasive ventilation.

    Science.gov (United States)

    Millar, D; Kirpalani, H

    2004-10-01

    Mechanical ventilation of the newborn infant has increased neonatal survival. However, this increased survival has come at the expense of increased morbidity, in the form of bronchopulmonary dysplasia, and at the cost of an expensive technology. Continuous positive airway pressure (CPAP) is accepted as conferring clinical benefit in supporting the recently extubated preterm infant and in the management of apnea of prematurity. Attention is now being drawn to physiologic and clinical evidence to support CPAP use, with or without early surfactant, as a primary treatment of hyaline membrane disease. The purpose of this review is to explore these proposed benefits of non invasive ventilation and place them in the context of current clinical evidence.

  7. 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...

  8. 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...

  9. 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...

  10. 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.

  11. 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.

  12. Chapter 8: Invasive fungal rhinosinusitis.

    Science.gov (United States)

    Duggal, Praveen; Wise, Sarah K

    2013-05-01

    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.

  13. 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

  14. Understanding macroscale invasion patterns and processes with FIA data

    Science.gov (United States)

    Songlin Fei; Basil V. Iannone III; Christopher M. Oswalt; Qinfeng Guo; Kevin M. Potter; Sonja N. Oswalt; Bryan C. Pijanowski; Gabriela C. Nunez-Mir

    2015-01-01

    Using empirical data from FIA, we modeled invasion richness and invasion prevalence as functions of 22 factors reflective of propagule pressure and/or habitat invasibility across the continental US. Our statistical models suggest that both propagule pressure and habitat invasibility contribute to macroscale patterns of forest plant invasions. Our investigation provides...

  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. 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…

  17. 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

  18. 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

  19. 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...

  20. Invasive Species Science Update (No. 1)

    Science.gov (United States)

    Mee-Sook Kim; Jack Butler

    2008-01-01

    This electronic newsletter (Invasive Species Science Update) is published by the Rocky Mountain Research Station (RMRS) Cross-Program, Interdisciplinary Project team on Invasive Species. This newsletter will be published 3 times per year and is intended to enhance communication among RMRS scientists, wildland managers, other partners, stakeholders, and customers about...

  1. Invasive Species Science Update (No. 6)

    Science.gov (United States)

    Paula Fornwalt

    2013-01-01

    The sixth issue of the Rocky Mountain Research Station's (RMRS) Invasive Species Science Update is now complete. Published approximately once per year, this newsletter keeps managers and other users up-to-date with recently completed and ongoing research by RMRS scientists, and covers breaking news related to invasive species issues. The newsletter is produced by...

  2. 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...

  3. 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

  4. 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 ...

  5. 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...

  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. 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

  8. 76 FR 30955 - Invasive Species Advisory Committee

    Science.gov (United States)

    2011-05-27

    ... broad array of issues related to preventing the introduction of invasive species and providing for their... primarily on invaders in the intermountain West. The meeting will focus on adapting management of invasive... ecology, climate change, land development, introduction pathways, and new invaders. ISAC will also consult...

  9. Invasive behaviour and depolarization effect of Pseudomonas ...

    African Journals Online (AJOL)

    ... of a constitutive calcium dependent NOS and that of an inducible NOS activated by LPS. Ours results also suggest that P. fluorescens cytotoxicity and invasion are not mutually exclusive events. Key Words: Cytotoxicity, Lipopolysaccharide, Patch-clamp, Invasion, Pseudomonas fluorescens. Afr. J. Clin. Exper. Microbiol.

  10. 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...... 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...

  11. Fusarium euwallaceae sp. nov.--a symbiotic fungus of Euwallacea sp., an invasive ambrosia beetle in Israel and California.

    Science.gov (United States)

    Freeman, S; Sharon, M; Maymon, M; Mendel, Z; Protasov, A; Aoki, T; Eskalen, A; O'Donnell, K

    2013-01-01

    The invasive Asian ambrosia beetle Euwallacea sp. (Coleoptera, Scolytinae, Xyleborini) and a novel Fusarium sp. that it farms in its galleries as a source of nutrition causes serious damage to more than 20 species of live trees and pose a serious threat to avocado production (Persea americana) in Israel and California. Adult female beetles are equipped with mandibular mycangia in which its fungal symbiont is transported within and from the natal galleries. Damage caused to the xylem is associated with disease symptoms that include sugar or gum exudates, dieback, wilt and ultimately host tree mortality. In 2012 the beetle was recorded on more than 200 and 20 different urban landscape species in southern California and Israel respectively. Euwallacea sp. and its symbiont are closely related to the tea shot-hole borer (E. fornicatus) and its obligate symbiont, F. ambrosium occurring in Sri Lanka and India. To distinguish these beetles, hereafter the unnamed xyleborine in Israel and California will be referred to as Euwallacea sp. IS/CA. Both fusaria exhibit distinctive ecologies and produce clavate macroconidia, which we think might represent an adaption to the species-specific beetle partner. Both fusaria comprise a genealogically exclusive lineage within Clade 3 of the Fusarium solani species complex (FSSC) that can be differentiated with arbitrarily primed PCR. Currently these fusaria can be distinguished only phenotypically by the abundant production of blue to brownish macroconidia in the symbiont of Euwallacea sp. IS/CA and their rarity or absence in F. ambrosium. We speculate that obligate symbiosis of Euwallacea and Fusarium, might have driven ecological speciation in these mutualists. Thus, the purpose of this paper is to describe and illustrate the novel, economically destructive avocado pathogen as Fusarium euwallaceae sp. nov. S. Freeman et al.

  12. 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.

  13. What makes the plant invasion possible? Paradigm of invasion mechanisms, theories and attributes

    Directory of Open Access Journals (Sweden)

    Prabhat Kumar Rai

    2015-06-01

    Full Text Available Plant invasion is the second most severe threat to biodiversity after habitat fragmentation. Invasive species are alien species whose introduction and spread threatens ecosystems, habitats or species with socio-cultural, economic and/or environmental harm, and harm to human health. Present review precisely describes the global problems of invasion in different ecosystems, continents and its multifaceted impacts. Plant invasion is now increasingly being recognized as global problem and various continents are adversely affected, although to a differential scale. Quest for the ecological mechanism lying behind the success of invasive species over native species has drawn the attention of researches worldwide particularly in context of diversity-stability relationship. Transport, colonization, establishment and landscape spread may be different steps in success of invasive plants and each and every step is checked through several ecological attributes. Further, several ecological attribute and hypothesis (enemy release, novel weapon, empty niche, evolution of increased competitive ability etc. were proposed pertaining to success of invasive plant species. However, single theory will not be able to account for invasion success among all environments as it may vary spatially and temporally. Therefore, in order to formulate a sustainable management plan for invasive plants, it is necessary to develop a synoptic view of the dynamic processes involved in the invasion process. Moreover, invasive species can act synergistically with other elements of global change, including land-use change, climate change, increased concentrations of atmospheric carbon dioxide and nitrogen deposition. Henceforth, a unified framework for biological invasions that reconciles and integrates the key features of the most commonly used invasion frame-works into a single conceptual model that can be applied to all human-mediated invasions.

  14. Invasive aspergillosis in two patients with Pearson syndrome.

    NARCIS (Netherlands)

    Warris, A.; Verweij, P.E.; Barton, R.C.; Crabbe, D.C.G.; Evans, E.G.V.; Meis, J.F.G.M.

    1999-01-01

    Invasive aspergillosis is a serious opportunistic infection in the immunocompromised host. In the pediatric population invasive aspergillosis is seen predominantly in patients with hematologic malignancie, chronic granullamotous disease (CGD) and AIDS. Invasive aspergillosis carries a high case

  15. 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

  16. Global threat to agriculture from invasive species.

    Science.gov (United States)

    Paini, Dean R; Sheppard, Andy W; Cook, David C; De Barro, Paul J; Worner, Susan P; Thomas, Matthew B

    2016-07-05

    Invasive species present significant threats to global agriculture, although how the magnitude and distribution of the threats vary between countries and regions remains unclear. Here, we present an analysis of almost 1,300 known invasive insect pests and pathogens, calculating the total potential cost of these species invading each of 124 countries of the world, as well as determining which countries present the greatest threat to the rest of the world given their trading partners and incumbent pool of invasive species. We find that countries vary in terms of potential threat from invasive species and also their role as potential sources, with apparently similar countries sometimes varying markedly depending on specifics of agricultural commodities and trade patterns. Overall, the biggest agricultural producers (China and the United States) could experience the greatest absolute cost from further species invasions. However, developing countries, in particular, Sub-Saharan African countries, appear most vulnerable in relative terms. Furthermore, China and the United States represent the greatest potential sources of invasive species for the rest of the world. The analysis reveals considerable scope for ongoing redistribution of known invasive pests and highlights the need for international cooperation to slow their spread.

  17. Assessing biofuel crop invasiveness: a case study.

    Directory of Open Access Journals (Sweden)

    Christopher Evan Buddenhagen

    Full Text Available BACKGROUND: There is widespread interest in biofuel crops as a solution to the world's energy needs, particularly in light of concerns over greenhouse-gas emissions. Despite reservations about their adverse environmental impacts, no attempt has been made to quantify actual, relative or potential invasiveness of terrestrial biofuel crops at an appropriate regional or international scale, and their planting continues to be largely unregulated. METHODOLOGY/PRINCIPAL FINDINGS: Using a widely accepted weed risk assessment system, we analyzed a comprehensive list of regionally suitable biofuel crops to show that seventy percent have a high risk of becoming invasive versus one-quarter of non-biofuel plant species and are two to four times more likely to establish wild populations locally or be invasive in Hawaii or in other locations with a similar climate. CONCLUSIONS/SIGNIFICANCE: Because of climatic and ecological similarities, predictions of biofuel crop invasiveness in Hawaii are applicable to other vulnerable island and subtropical ecosystems worldwide. We demonstrate the utility of an accessible and scientifically proven risk assessment protocol that allows users to predict if introduced species will become invasive in their region of interest. Other evidence supports the contention that propagule pressure created by extensive plantings will exacerbate invasions, a scenario expected with large-scale biofuel crop cultivation. Proactive measures, such as risk assessments, should be employed to predict invasion risks, which could then be mitigated via implementation of appropriate planting policies and adoption of the "polluter-pays" principle.

  18. Non invasive wearable sensor for indirect glucometry.

    Science.gov (United States)

    Zilberstein, Gleb; Zilberstein, Roman; Maor, Uriel; Righetti, Pier Giorgio

    2018-04-02

    A non-invasive mini-sensor for blood glucose concentration assessment has been developed. The monitoring is performed by gently pressing a wrist or fingertip onto the chemochromic mixture coating a thin glass or polymer film positioned on the back panel of a smart watch with PPG/HRM (photoplethysmographic/heart rate monitoring sensor). The various chemochromic components measure the absolute values of the following metabolites present in the sweat: acetone, acetone beta-hydroxybutirate, aceto acetate, water, carbon dioxide, lactate anion, pyruvic acid, Na and K salts. Taken together, all these parameters give information about blood glucose concentration, calculated via multivariate analysis based on neural network algorithms built into the sensor. The Clarke Error Grid shows an excellent correlation between data measured by the standard invasive glucose analyser and the present non-invasive sensor, with all points aligned along a 45 degree diagonal and contained almost exclusively in sector A. Graphs measuring glucose levels five times a day (prior, during and after breakfast and prior, during and after lunch), for different individuals (male and female) show a good correlation between the two curves of conventional, invasive meters vs. the non-invasive sensor, with an error of ±15%. This novel, non-invasive sensor for indirect glucometry is fully miniaturized, easy to use and operate and could represent a valid alternative in clinical settings and for individual, personal users, to current, invasive tools. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  19. Using shallow seismic tomography to characterize patterns of near-surface weathering and the mobile-immobile regolith transition: Implications for the erodibility and morphology of hillslopes.

    Science.gov (United States)

    Clarke, B. A.; Kirby, E.; Burbank, D. W.; West, N.

    2014-12-01

    We use 2D tomography of P- and S-wave velocities (Vp, Vs), based on seismic refraction and surface wave analyses, to characterize subsurface architecture and erodibility of hillslopes. Calibrating the seismic imagery with direct field observations allows us to quantify mechanical properties, image depth-dependent variations in weathering intensity, and identify the mobile-immobile regolith transition and differences in transport efficiency of mobile layers. We conducted a cross-CZO comparison of N- and S-facing slopes at Boulder Creek and Shale Hills CZOs (BcCZO and SSHCZO) to investigate how near-surface weathering and hillslope morphology are influenced by differences in regional geology and climatic as well as local variations in aspect-controlled microclimate. Niwot Ridge (BcCZO) is a high alpine site with minimal soil/veg cover, characterized by steeper S-facing hillslopes; whereas, SSHCZO is a temperate, densely-forested, soil-mantled site with steeper N-facing slopes. On Niwot Ridge, the depth of the weathering front and thickness of mobile regolith are substantially greater on shallower N-facing slopes; however, velocity-based estimates of transport efficiency are higher on S-facing slopes. Although, thin mobile regolith on S-facing slopes may be weaker (slower V), the lower gradient of N-facing slopes and southward asymmetry of the ridge divide, suggests greater transport efficiency on N-facing aspects. This can be explained by the dominance of frost/freeze process on N-facing slopes, which can efficiently develop and transport the thick mobile regolith. At SSHCZO, depths of weathering fronts are invariant with slope aspect, suggesting that aspect control is not a predominant mechanism driving regolith production. Mobile regolith thickness, however, is more than 2-fold greater on N-facing slopes. Additionally, mobile regolith on both slope aspects is primarily composed of well-developed soils. N-facing soils are thicker with greater cohesion, moisture, and

  20. 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.

  1. Invasion exponents in biological networks

    Science.gov (United States)

    Demetrius, Lloyd; Gundlach, Volker Matthias; Ochs, Gunter

    2009-03-01

    This article is concerned with the characterization of invasion exponents in biological networks defined by a population of replicating elements: molecules, cells, higher organisms. We show that the outcome of competition between an invader and a resident population is a stochastic process, determined by the rate at which a population returns to its steady state after a random perturbation in the parameters that characterize the replicating elements. This return rate is defined by the macroscopic parameter evolutionary entropy, a measure of the diversity of the interaction between the individuals in the population. We also show that the evolutionary stability of a population, that is the invulnerability of a resident to the introduction of an invader competing for the available resources, are given by extremal states of entropy. These results which pertain to networks of interacting molecules, cells and higher organisms, are generalizations of results established for demographic networks, that is populations of replicating organisms parametrized by the ages at which they reproduce and die.

  2. 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.

  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. Excluding access to invasion hubs can contain the spread of an invasive vertebrate.

    Science.gov (United States)

    Florance, Daniel; Webb, Jonathan K; Dempster, Tim; Kearney, Michael R; Worthing, Alex; Letnic, Mike

    2011-10-07

    Many biological invasions do not occur as a gradual expansion along a continuous front, but result from the expansion of satellite populations that become established at 'invasion hubs'. Although theoretical studies indicate that targeting control efforts at invasion hubs can effectively contain the spread of invasions, few studies have demonstrated this in practice. In arid landscapes worldwide, humans have increased the availability of surface water by creating artificial water points (AWPs) such as troughs and dams for livestock. By experimentally excluding invasive cane toads (Bufo marinus) from AWP, we show that AWP provide a resource subsidy for non-arid-adapted toads and serve as dry season refuges and thus invasion hubs for cane toads in arid Australia. Using data on the distribution of permanent water in arid Australia and the dispersal potential of toads, we predict that systematically excluding toads from AWP would reduce the area of arid Australia across which toads are predicted to disperse and colonize under average climatic conditions by 38 per cent from 2,242,000 to 1,385,000 km(2). Our study shows how human modification of hydrological regimes can create a network of invasion hubs that facilitates a biological invasion, and confirms that targeted control at invasion hubs can reduce landscape connectivity to contain the spread of an invasive vertebrate.

  5. 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.

  6. Candida albicans hyphal invasion: thigmotropism or chemotropism?

    Science.gov (United States)

    Davies, J M; Stacey, A J; Gilligan, C A

    1999-02-15

    Hyphae of the human pathogenic fungus Candida albicans exhibit thigmotropic behaviour in vitro, in common with phytopathogenic and saprotrophic fungi. An examination of the literature on C. albicans hyphal penetration of epithelial and endothelial membranes does not support the premise that hyphal thigmotropism plays a major role in tissue invasion. Further experimentation is now required to assess thigmotropic behaviour on host membranes and vaginal epithelial cells are suggested as a test model. It is proposed that while thigmotropism may and invasion of tissue invaginations, chemotropism can explain C. albicans hyphal invasion patterns of both endothelium and epithelium.

  7. Aquatic invasive species: Lessons from cancer research

    Science.gov (United States)

    Sepulveda, Adam; Ray, Andrew; Al-Chokhachy, Robert K.; Muhlfeld, Clint C.; Gresswell, Robert E.; Gross, Jackson A.; Kershner, Jeffrey L.

    2014-01-01

    Aquatic invasive species are disrupting ecosystems with increasing frequency. Successful control of these invasions has been rare: Biologists and managers have few tools for fighting aquatic invaders. In contrast, the medical community has long worked to develop tools for preventing and fighting cancer. Its successes are marked by a coordinated research approach with multiple steps: prevention, early detection, diagnosis, treatment options and rehabilitation. The authors discuss how these steps can be applied to aquatic invasive species, such as the American bullfrog (Lithobates catesbeianus), in the Northern Rocky Mountain region of the United States, to expedite tool development and implementation along with achievement of biodiversity conservation goals.

  8. 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

  9. How can phytochemists benefit from invasive plants?

    Science.gov (United States)

    Fan, Peihong; Marston, Andrew

    2009-10-01

    The phenomenon of invasive alien species has become one of the greatest threats to the biological diversity of the planet, placing major constraints on development. In order to provide the tools needed to address this pervasive issue, the current knowledge on invasive species must be further developed with a cross-sectoral and multi-disciplinary approach. Recent theories of invasion propose that exotic plants probably produce secondary metabolites which can be allelopathic, anti-herbivore, anti-microbial and which are either unique or underrepresented in the plants' new range. This review attempts to attract the attention of phytochemists to study either the mechanisms of plant invasion or to use this widespread plant resource for humans.

  10. The social dimensions of invasive plants.

    Science.gov (United States)

    Head, Lesley

    2017-06-06

    Invasive plants pose a major environmental management issue. Research into the social dimensions of this issue has flourished over the past decade, as part of the critical examination of relations between human and nonhuman worlds. The social sciences and humanities have made substantial contributions to conceptualizing invasiveness and nativeness; understanding the perceptions, attitudes and values of diverse stakeholders; and analysing the politics and practices of invasive plant management. Cultural analysis allows areas of conflict and commonality to be identified. Social complexity must be added to ecological complexity to understand the causal relationships underlying invasions; and linear understandings of science-policy relationships are too simplistic. Productive connections have been established between recent social and natural science approaches in the context of rapid environmental change and unpredictable futures. Nonetheless, the prevalence of human exceptionalism in the ecological sciences constitutes a major point of divergence between social and natural science perspectives.

  11. 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.

  12. 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 ...

  13. 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...

  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. [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.

  16. Robot-assisted minimally invasive esophagectomy

    NARCIS (Netherlands)

    van Hillegersberg, R.; Seesing, M. F. J.; Brenkman, H. J. F.; Ruurda, J. P.

    Esophagolymphadenectomy is the cornerstone of multimodality treatment for resectable esophageal cancer. The preferred surgical approach is transthoracic, with a two-field lymph node dissection and gastric conduit reconstruction. A minimally invasive approach has been shown to reduce postoperative

  17. 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...

  18. 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...

  19. 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...

  20. 75 FR 29359 - Invasive Species Advisory Committee

    Science.gov (United States)

    2010-05-25

    ..., opportunities for green jobs creation within invasive species efforts, ballast water related issues, and the..., 2010. ADDRESSES: The Argonaut Hotel, 495 Jefferson Street at Hyde, San Francisco, California 94109-1314...

  1. 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...... observed to be species and community combination specific. This evolutionary study represents a novel in silico attempt to tackle invasiveness in an experimental framework, and may provide a new methodology for tackling these issues....

  2. 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.

  3. 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.

  4. 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

  5. Perspectives on invasive amphibians in Brazil.

    Directory of Open Access Journals (Sweden)

    Lucas Rodriguez Forti

    Full Text Available Introduced species have the potential to become invasive and jeopardize entire ecosystems. The success of species establishing viable populations outside their original extent depends primarily on favorable climatic conditions in the invasive ranges. Species distribution modeling (SDM can thus be used to estimate potential habitat suitability for populations of invasive species. Here we review the status of six amphibian species with invasive populations in Brazil (four domestic species and two imported species. We (i modeled the current habitat suitability and future potential distribution of these six focal species, (ii reported on the disease status of Eleutherodactylus johnstonei and Phyllodytes luteolus, and (iii quantified the acoustic overlap of P. luteolus and Leptodactylus labyrinthicus with three co-occurring native species. Our models indicated that all six invasive species could potentially expand their ranges in Brazil within the next few decades. In addition, our SDMs predicted important expansions in available habitat for 2 out of 6 invasive species under future (2100 climatic conditions. We detected high acoustic niche overlap between invasive and native amphibian species, underscoring that acoustic interference might reduce mating success in local frogs. Despite the American bullfrog Lithobates catesbeianus being recognized as a potential reservoir for the frog-killing fungus Batrachochytrium dendrobatidis (Bd in Brazil, we did not detect Bd in the recently introduced population of E. johnstonei and P. luteolus in the State of São Paulo. We emphasize that the number of invasive amphibian species in Brazil is increasing exponentially, highlighting the urgent need to monitor and control these populations and decrease potential impacts on the locally biodiverse wildlife.

  6. 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.

  7. 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

  8. The radiological diagnosis of invasive thymomas

    International Nuclear Information System (INIS)

    Dewes, W.; Schrappe-Baecher, M.; Focke-Wenzel, E.K.; Schmitz-Draeger, H.G.; Staedtische Krankenanstalten Koeln-Merheim

    1986-01-01

    Between January 1981 and September 1985, invasive thymomas were diagnosed in 13 patients attending the municipal hospital at Koeln-Merheim. All these patients were examined radiologically and the tumour removed at thoracotomy, and irradiated in our Radiotherapy Clinic. Invasive thymomas appear as space-occupying lesions on chest radiographs taken in two planes, or on computed tomography. Infiltration by the thymoma in stages III and IV can be demonstrated by computed tomography. (orig.) [de

  9. Dynamics of cancerous tissue correlates with invasiveness

    Science.gov (United States)

    West, Ann-Katrine Vransø; Wullkopf, Lena; Christensen, Amalie; Leijnse, Natascha; Tarp, Jens Magelund; Mathiesen, Joachim; Erler, Janine Terra; Oddershede, Lene Broeng

    2017-03-01

    Two of the classical hallmarks of cancer are uncontrolled cell division and tissue invasion, which turn the disease into a systemic, life-threatening condition. Although both processes are studied, a clear correlation between cell division and motility of cancer cells has not been described previously. Here, we experimentally characterize the dynamics of invasive and non-invasive breast cancer tissues using human and murine model systems. The intrinsic tissue velocities, as well as the divergence and vorticity around a dividing cell correlate strongly with the invasive potential of the tissue, thus showing a distinct correlation between tissue dynamics and aggressiveness. We formulate a model which treats the tissue as a visco-elastic continuum. This model provides a valid reproduction of the cancerous tissue dynamics, thus, biological signaling is not needed to explain the observed tissue dynamics. The model returns the characteristic force exerted by an invading cell and reveals a strong correlation between force and invasiveness of breast cancer cells, thus pinpointing the importance of mechanics for cancer invasion.

  10. Non-invasive ventilation for cystic fibrosis.

    Science.gov (United States)

    Moran, Fidelma; Bradley, Judy M; Piper, Amanda J

    2017-02-20

    Non-invasive ventilation may be a means to temporarily reverse or slow the progression of respiratory failure in cystic fibrosis by providing ventilatory support and avoiding tracheal intubation. Using non-invasive ventilation, in the appropriate situation or individuals, can improve lung mechanics through increasing airflow and gas exchange and decreasing the work of breathing. Non-invasive ventilation thus acts as an external respiratory muscle. This is an update of a previously published review. To compare the effect of non-invasive ventilation versus no non-invasive ventilation in people with cystic fibrosis for airway clearance, during sleep and during exercise. We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches, handsearching relevant journals and abstract books of conference proceedings. We searched the reference lists of each trial for additional publications possibly containing other trials.Most recent search: 08 August 2016. Randomised controlled trials comparing a form of pressure preset or volume preset non-invasive ventilation to no non-invasive ventilation used for airway clearance or during sleep or exercise in people with acute or chronic respiratory failure in cystic fibrosis. Three reviewers independently assessed trials for inclusion criteria and methodological quality, and extracted data. Ten trials met the inclusion criteria with a total of 191 participants. Seven trials evaluated single treatment sessions, one evaluated a two-week intervention, one evaluated a six-week intervention and one a three-month intervention. It is only possible to blind trials of airway clearance and overnight ventilatory support to the outcome assessors. In most of the trials we judged there was an unclear risk of bias with regards to blinding due to inadequate descriptions. The six-week trial was the only one judged to have a low risk of bias for all

  11. 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].

  12. Worldwide Alien Invasion: A Methodological Approach to Forecast the Potential Spread of a Highly Invasive Pollinator.

    Science.gov (United States)

    Acosta, André L; Giannini, Tereza C; Imperatriz-Fonseca, Vera L; Saraiva, Antonio M

    2016-01-01

    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.

  13. Invasive Insects Differ from Non-Invasive in Their Thermal Requirements.

    Directory of Open Access Journals (Sweden)

    Vojtěch Jarošík

    Full Text Available We tested whether two basic thermal requirements for insect development, lower developmental thresholds, i.e. temperatures at which development ceases, and sums of effective temperatures, i.e. numbers of day degrees above the lower developmental thresholds necessary to complete development, differ among insect species that proved to be successful invaders in regions outside their native range and those that did not. Focusing on species traits underlying invasiveness that are related to temperature provides insights into the mechanisms of insect invasions. The screening of thermal requirements thus could improve risk-assessment schemes by incorporating these traits in predictions of potentially invasive insect species. We compared 100 pairs of taxonomically-related species originating from the same continent, one invasive and the other not reported as invasive. Invasive species have higher lower developmental thresholds than those never recorded outside their native ranges. Invasive species also have a lower sum of effective temperatures, though not significantly. However, the differences between invasive and non-invasive species in the two physiological measures were significantly inversely correlated. This result suggests that many species are currently prevented from invading by low temperatures in some parts of the world. Those species that will overcome current climatic constraints in regions outside their native distribution due to climate change could become even more serious future invaders than present-day species, due to their potentially faster development.

  14. 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.

  15. Adaptive invasive species distribution models: A framework for modeling incipient invasions

    Science.gov (United States)

    Uden, Daniel R.; Allen, Craig R.; Angeler, David G.; Corral, Lucia; Fricke, Kent A.

    2015-01-01

    The utilization of species distribution model(s) (SDM) for approximating, explaining, and predicting changes in species’ geographic locations is increasingly promoted for proactive ecological management. Although frameworks for modeling non-invasive species distributions are relatively well developed, their counterparts for invasive species—which may not be at equilibrium within recipient environments and often exhibit rapid transformations—are lacking. Additionally, adaptive ecological management strategies address the causes and effects of biological invasions and other complex issues in social-ecological systems. We conducted a review of biological invasions, species distribution models, and adaptive practices in ecological management, and developed a framework for adaptive, niche-based, invasive species distribution model (iSDM) development and utilization. This iterative, 10-step framework promotes consistency and transparency in iSDM development, allows for changes in invasive drivers and filters, integrates mechanistic and correlative modeling techniques, balances the avoidance of type 1 and type 2 errors in predictions, encourages the linking of monitoring and management actions, and facilitates incremental improvements in models and management across space, time, and institutional boundaries. These improvements are useful for advancing coordinated invasive species modeling, management and monitoring from local scales to the regional, continental and global scales at which biological invasions occur and harm native ecosystems and economies, as well as for anticipating and responding to biological invasions under continuing global change.

  16. Galactomannan detection for invasive aspergillosis in immunocompromised patients

    NARCIS (Netherlands)

    Leeflang, Mariska M. G.; Debets-Ossenkopp, Yvette J.; Wang, Junfeng; Visser, Caroline E.; Scholten, Rob J. P. M.; Hooft, Lotty; Bijlmer, Henk A.; Reitsma, Johannes B.; Zhang, Mingming; Bossuyt, Patrick M. M.; Vandenbroucke-Grauls, Christina M.

    2015-01-01

    Invasive aspergillosis is the most common life-threatening opportunistic invasive mycosis in immunocompromised patients. A test for invasive aspergillosis should neither be too invasive nor too great a burden for the already weakened patient. The serum galactomannan enzyme-linked immunosorbent assay

  17. Effective radiation doses associated with non-invasive versus invasive assessment of coronary anatomy and physiology.

    Science.gov (United States)

    Toth, G G; Ntalianis, A; Ntarladimas, Y; de Booij, M; De Winter, O; Barbato, E; Pilet, B; Van Mieghem, C; Wijns, W; De Bruyne, B

    2015-06-01

    To compare the effective radiation dose (ERD) needed to obtain information on coronary anatomy and physiology by a non-invasive versus an invasive diagnostic strategy. Knowledge of anatomy and physiology is needed for management of patients with coronary artery disease (CAD). There is, however, a growing concern about detrimental long-term effects of radiation associated with diagnostic procedures. In a total of 671 patients with suspected CAD, we compared the ERD needed to obtain anatomical and physiological information through a non-invasive strategy or an invasive strategy. The non-invasive strategy consisted of coronary computed tomography angiography (CCTA) and single photon emission computed tomography (SPECT). The invasive strategy included coronary angiography (CA) and fractional flow reserve (FFR) measurement. In 464 patients, the data were acquired in Period 2009 and in 207 the data were acquired in Period 2011 (after each period, the CCTA- and the CA-equipment had been upgraded). For the Period 2009 total ERD of the non-invasive approach was significantly larger compared to the invasive approach (28.45 ± 5.37 mSv versus 15.79 ± 7.95 mSv, respectively; P < 0.0001). For Period 2011, despite the significant decrease in ERD for both groups (P<0.0001 for both), the ERD remained higher for the non-invasive approach compared to the invasive approach (16.67 ± 10.45 mSv vs. 10.36 ± 5.87 mSv, respectively; P < 0.0001). Simulation of various diagnostic scenarios showed cumulative radiation dose is the lowest when a first positive test is followed by an invasive strategy. To obtain anatomic and physiologic information in patients with suspected CAD, the combination of CA and FFR is associated with lower ERD than the combination of CCTA and SPECT. © 2014 Wiley Periodicals, Inc.

  18. 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.

  19. 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

  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. The impact of invasive fish and invasive riparian plants on the ...

    African Journals Online (AJOL)

    Invasive fish and plants are widespread in the rivers and riparian zones of the Cape Floristic Region of South Africa and represent potential threats to the highly endemic freshwater fauna. We investigated the impact of invasive smallmouth bass (Micropterus dolomieu) and black wattle (Acacia mearnsii) on assemblages of ...

  2. 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

  3. Leaf litter variation influences invasion dynamics in the invasive wetland grass Phalaris arundinacea

    NARCIS (Netherlands)

    Kaproth, M.A.; Eppinga, M.B.; Molofsky, J.

    High litter mass is hypothesized to produce an invader-directed invasion by changing ecosystem properties such as nutrient cycling rates and light availability. An invasive plant species that stimulates litter accumulation may induce a positive feedback when it benefits from high litter

  4. 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.

  5. Cortactin is associated with perineural invasion in the deep invasive front area of laryngeal carcinomas

    DEFF Research Database (Denmark)

    Ambrosio, Eliane Papa; Rosa, Fabíola Encinas; Domingues, Maria Aparecida Custódio

    2011-01-01

    The cortactin gene, mapped at 11q13, has been associated with an aggressive clinical course in many cancers because of its function of invasiveness. This study evaluated CTTN protein and its prognostic value in the deep invasive front and superficial areas of laryngeal squamous cell carcinomas. T...

  6. Minimally invasive surgical therapies for benign prostatic hypertrophy: The rise in minimally invasive surgical therapies

    Directory of Open Access Journals (Sweden)

    Daniel Christidis

    2017-06-01

    The role of minimally invasive surgical therapies in the treatment of BPH is still yet to be strongly defined. Given the experimental nature of many of the modalities, further study is required prior to their recommendation as alternatives to invasive surgical therapy. More mature evidence is required for the analysis of durability of effect of these therapies to make robust conclusions of their effectiveness.

  7. blood pressure influence of the the Invasive v. non-invasive

    African Journals Online (AJOL)

    1991-02-02

    Feb 2, 1991 ... thesis that large differences between the invasive and non- invasive measurements could be predicted by an .... Washington, USA) and the resultant pressure trace and digital systolic, mean and diastolic pressures as well as the ..... Publishing, 1978; 49-82. 8. Ladin Z, Trautman E, Teplick R. Contribution of ...

  8. 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 ...

  9. Secondary invasion and re-invasion after Russian-olive removal and revegetation

    Science.gov (United States)

    Russian olive is a nitrogen-fixing tree invading riparian corridors in the Northern Great Plains. Native species establishment can be hampered by invasive plant soil legacies that may be particularly likely in the case of Russian olive, and understory species that survive the invasion may be only a ...

  10. 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...

  11. 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.

  12. 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

  13. Minimally invasive surgery for Achilles tendon pathologies

    Directory of Open Access Journals (Sweden)

    Nicola Maffulli

    2010-07-01

    Full Text Available Nicola Maffulli1, Umile Giuseppe Longo2, Filippo Spiezia2, Vincenzo Denaro21Centre for Sports and Exercise Medicine, Barts and The London School of Medicine and Dentistry, London, England; 2Department of Orthopedic and Trauma Surgery, Campus Bio-Medico University, Rome, ItalyAbstract: Minimally invasive trauma and orthopedic surgery is increasingly common, though technically demanding. Its use for pathologies of the Achilles tendon (AT hold the promise to allow faster recovery times, shorter hospital stays, and improved functional outcomes when compared to traditional open procedures, which can lead to difficulty with wound healing because of the tenuous blood supply and increased chance of wound breakdown and infection. We present the recent advances in the field of minimally invasive AT surgery for tendinopathy, acute ruptures, chronic tears, and chronic avulsions of the AT. In our hands, minimally invasive surgery has provided similar results to those obtained with open surgery, with decreased perioperative morbidity, decreased duration of hospital stay, and reduced costs. So far, the studies on minimally invasive orthopedic techniques are of moderate scientific quality with short follow-up periods. Multicenter studies with longer follow-up are needed to justify the long-term advantages of these techniques over traditional ones.Keywords: tendinopathy, rupture, percutanous repair, less invasive

  14. 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.

  15. The Role of Hypoxia in Glioblastoma Invasion

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    Ana Rita Monteiro

    2017-11-01

    Full Text Available Glioblastoma multiforme (GBM, a grade IV astrocytoma, is the most common and deadly type of primary malignant brain tumor, with a patient’s median survival rate ranging from 15 to 17 months. The current treatment for GBM involves tumor resection surgery based on MRI image analysis, followed by radiotherapy and treatment with temozolomide. However, the gradual development of tumor resistance to temozolomide is frequent in GBM patients leading to subsequent tumor regrowth/relapse. For this reason, the development of more effective therapeutic approaches for GBM is of critical importance. Low tumor oxygenation, also known as hypoxia, constitutes a major concern for GBM patients, since it promotes cancer cell spreading (invasion into the healthy brain tissue in order to evade this adverse microenvironment. Tumor invasion not only constitutes a major obstacle to surgery, radiotherapy, and chemotherapy, but it is also the main cause of death in GBM patients. Understanding how hypoxia triggers the GBM cells to become invasive is paramount to developing novel and more effective therapies against this devastating disease. In this review, we will present a comprehensive examination of the available literature focused on investigating how GBM hypoxia triggers an invasive cancer cell phenotype and the role of these invasive proteins in GBM progression.

  16. Biological invasions, climate change and genomics.

    Science.gov (United States)

    Chown, Steven L; Hodgins, Kathryn A; Griffin, Philippa C; Oakeshott, John G; Byrne, Margaret; Hoffmann, Ary A

    2015-01-01

    The rate of biological invasions is expected to increase as the effects of climate change on biological communities become widespread. Climate change enhances habitat disturbance which facilitates the establishment of invasive species, which in turn provides opportunities for hybridization and introgression. These effects influence local biodiversity that can be tracked through genetic and genomic approaches. Metabarcoding and metagenomic approaches provide a way of monitoring some types of communities under climate change for the appearance of invasives. Introgression and hybridization can be followed by the analysis of entire genomes so that rapidly changing areas of the genome are identified and instances of genetic pollution monitored. Genomic markers enable accurate tracking of invasive species' geographic origin well beyond what was previously possible. New genomic tools are promoting fresh insights into classic questions about invading organisms under climate change, such as the role of genetic variation, local adaptation and climate pre-adaptation in successful invasions. These tools are providing managers with often more effective means to identify potential threats, improve surveillance and assess impacts on communities. We provide a framework for the application of genomic techniques within a management context and also indicate some important limitations in what can be achieved.

  17. Cancer stem cell contribution to glioblastoma invasiveness.

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    Ortensi, Barbara; Setti, Matteo; Osti, Daniela; Pelicci, Giuliana

    2013-02-28

    Glioblastoma (GBM) is the most aggressive and lethal brain tumor in adults. Its invasive nature currently represents the most challenging hurdle to surgical resection. The mechanism adopted by GBM cells to carry out their invasive strategy is an intricate program that recalls what takes place in embryonic cells during development and in carcinoma cells during metastasis formation, the so-called epithelial-to-mesenchymal transition. GBM cells undergo a series of molecular and conformational changes shifting the tumor toward mesenchymal traits, including extracellular matrix remodeling, cytoskeletal re-patterning, and stem-like trait acquisition. A deeper understanding of the mechanisms driving the whole infiltrative process represents the first step toward successful treatment of this pathology. Here, we review recent findings demonstrating the invasive nature of GBM cancer stem cells, together with novel candidate molecules associated with both cancer stem cell biology and GBM invasion, like doublecortin and microRNAs. These findings may affect the design of effective therapies currently not considered for GBM invasive progression.

  18. Genomic comparison of invasive and rare non-invasive strains reveals Porphyromonas gingivalis genetic polymorphisms

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    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.

  19. Postoperative radiation therapy for completely resected invasive thymoma. Prognostic value of pleural invasion for intrathoracic control

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    Ogawa, Kazuhiko; Toita, Takafumi; Kakinohana, Yasumasa; Kamata, Minoru; Koja, Kageharu [Ryukyus Univ., Uehara, Okinawa (Japan). School of Medicine; Genga, Keiichiro

    1999-10-01

    Optimal management of postoperative radiation therapy for completely resected invasive thymoma remains controversial. This study was conducted to assess the efficacy of postoperative mediastinal irradiation in patients with completely resected invasive thymoma. Between 1981 and 1996, 21 patients with completely resected invasive thymoma were referred for postoperative mediastinal irradiation. The distribution of Masaoka stages was stage II in 14 patients and stage III in seven patients. Nine patients had pleural invasion by the tumor. Thirteen patients were treated with a localized field and eight were treated with the whole mediastinal field with boost. The total dose to the primary tumor was 40-61 Gy (median: 52 Gy). The median follow-up time of the 16 living patients was 67 months (range: 29-202 months). The 5- and 10-year actuarial overall survival rates in all patients were both 77%. Relapses were observed in five patients, in all of whom the sites of the first relapse involved pleural dissemination. There were no relapses within the irradiated field in any of the 21 cases. Five of nine (56%) patients with pleural invasion had relapse of pleural dissemination, while 0 of 12 (0%) patients without pleural invasion had relapse. In univariate analysis, pleural invasion had a statistically significant impact on intrathoracic control (P=0.01). The results indicated that pleural invasion might be predictive of pleural-based relapse for completely resected invasive thymoma. In patients with pleural invasion, mediastinal irradiation alone might be insufficient to avoid pleural-based relapse even after complete resection. (author)

  20. Pollination of a native plant changes with distance and density of invasive plants in a simulated biological invasion.

    Science.gov (United States)

    Bruckman, Daniela; Campbell, Diane R

    2016-08-01

    Effects of an exotic plant on pollination may change as the invasive increases in density. Quantity of pollinator visits to a native may increase, decrease, or change nonlinearly, while visit quality is likely to decrease with greater interspecific pollen movement. How visit quantity and quality contribute to the effect on reproductive success at each invasion stage has not been measured. We simulated four stages of invasion by Brassica nigra by manipulating the neighborhood of potted plants of the native Phacelia parryi in a field experiment. Stages were far from the invasion, near the invasion, intermixed with the invasive at low density, and intermixed at high density. We measured pollinator visitation, conspecific and invasive pollen deposition, and seed set for P. parryi at each stage. Native individuals near invasive plants and within areas of low invasive density showed greatest seed production, as expected from concurrent changes in conspecific and invasive pollen deposition. Those plants experienced facilitation of visits and received more conspecific pollen relative to plants farther from invasives. Native individuals within high invasive density also received frequent visits by many pollinators (although not honeybees), but the larger receipt of invasive pollen predicted interference with pollen tubes that matched patterns in seed set. Pollinator visitation was highest when exotic plants were nearby. Detrimental effects of heterospecific pollen deposition were highest at high exotic density. Our study quantified how reproduction benefits from near proximity to a showy invasive, but is still vulnerable when the invasive reaches high density. © 2016 Botanical Society of America.