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Sample records for promotes species coexistence

  1. Competitive intransitivity promotes species coexistence.

    Science.gov (United States)

    Laird, Robert A; Schamp, Brandon S

    2006-08-01

    Using a spatially explicit cellular automaton model with local competition, we investigate the potential for varied levels of competitive intransitivity (i.e., nonhierarchical competition) to promote species coexistence. As predicted, on average, increased levels of intransitivity result in more sustained coexistence within simulated communities, although the outcome of competition also becomes increasingly unpredictable. Interestingly, even a moderate degree of intransitivity within a community can promote coexistence, in terms of both the length of time until the first competitive exclusion and the number of species remaining in the community after 500 simulated generations. These results suggest that modest levels of intransitivity in nature, such as those that are thought to be characteristic of plant communities, can contribute to coexistence and, therefore, community-scale biodiversity. We explore a potential connection between competitive intransitivity and neutral theory, whereby competitive intransitivity may represent an important mechanism for "ecological equivalence."

  2. Arbuscular mycorrhizal fungal diversity and natural enemies promote coexistence of tropical tree species

    Science.gov (United States)

    Benedicte Bachelot; María Uriarte; Krista L. McGuire; Jill Thompson; Jess Zimmerman

    2017-01-01

    Negative population feedbacks mediated by natural enemies can promote species coexistence at the community scale through disproportionate mortality of numerically dominant (common) tree species. Simultaneously, associations with arbuscular mycorrhizal fungi (AMF) can result in positive effects on tree populations. Coupling data on seedling foliar damage from herbivores...

  3. Antagonistic interactions between an invasive alien and a native coccinellid species may promote coexistence.

    Science.gov (United States)

    Hentley, William T; Vanbergen, Adam J; Beckerman, Andrew P; Brien, Melanie N; Hails, Rosemary S; Jones, T Hefin; Johnson, Scott N

    2016-07-01

    Despite the capacity of invasive alien species to alter ecosystems, the mechanisms underlying their impact remain only partly understood. Invasive alien predators, for example, can significantly disrupt recipient communities by consuming prey species or acting as an intraguild predator (IGP). Behavioural interactions are key components of interspecific competition between predators, yet these are often overlooked invasion processes. Here, we show how behavioural, non-lethal IGP interactions might facilitate the establishment success of an invading alien species. We experimentally assessed changes in feeding behaviour (prey preference and consumption rate) of native UK coccinellid species (Adalia bipunctata and Coccinella septempunctata), whose populations are, respectively, declining and stable, when exposed to the invasive intraguild predator, Harmonia axyridis. Using a population dynamics model parameterized with these experimental data, we predicted how intraguild predation, accommodating interspecific behavioural interactions, might impact the abundance of the native and invasive alien species over time. When competing for the same aphid resource, the feeding rate of A. bipunctata significantly increased compared to the feeding in isolation, while the feeding rate of H. axyridis significantly decreased. This suggests that despite significant declines in the UK, A. bipunctata is a superior competitor to the intraguild predator H. axyridis. In contrast, the behaviour of non-declining C. septempunctata was unaltered by the presence of H. axyridis. Our experimental data show the differential behavioural plasticity of competing native and invasive alien predators, but do not explain A. bipunctata declines observed in the UK. Using behavioural plasticity as a parameter in a population dynamic model for A. bipunctata and H. axyridis, coexistence is predicted between the native and invasive alien following an initial period of decline in the native species. We

  4. Antagonistic interactions between an invasive alien and a native coccinellid species may promote coexistence.

    OpenAIRE

    Hentley, W.T.; Vanbergen, A.J.; Beckerman, A.P.; Brien, M.N.; Hails, R.S.; Jones, T.H.; Johnson, S.N.

    2016-01-01

    1. Despite the capacity of invasive alien species to alter ecosystems, the mechanisms underlying their impact remain only partly understood. Invasive alien predators, for example, can significantly disrupt recipient communities by consuming prey species or acting as an intraguild predator (IGP). 2. Behavioural interactions are key components of interspecific competition between predators,yet these are often overlooked invasion processes. Here, we show how behavioural, nonlethal IGP intera...

  5. Spatial Complementarity and the Coexistence of Species

    Science.gov (United States)

    Velázquez, Jorge; Garrahan, Juan P.; Eichhorn, Markus P.

    2014-01-01

    Coexistence of apparently similar species remains an enduring paradox in ecology. Spatial structure has been predicted to enable coexistence even when population-level models predict competitive exclusion if it causes each species to limit its own population more than that of its competitor. Nevertheless, existing hypotheses conflict with regard to whether clustering favours or precludes coexistence. The spatial segregation hypothesis predicts that in clustered populations the frequency of intra-specific interactions will be increased, causing each species to be self-limiting. Alternatively, individuals of the same species might compete over greater distances, known as heteromyopia, breaking down clusters and opening space for a second species to invade. In this study we create an individual-based model in homogeneous two-dimensional space for two putative sessile species differing only in their demographic rates and the range and strength of their competitive interactions. We fully characterise the parameter space within which coexistence occurs beyond population-level predictions, thereby revealing a region of coexistence generated by a previously-unrecognised process which we term the triadic mechanism. Here coexistence occurs due to the ability of a second generation of offspring of the rarer species to escape competition from their ancestors. We diagnose the conditions under which each of three spatial coexistence mechanisms operates and their characteristic spatial signatures. Deriving insights from a novel metric — ecological pressure — we demonstrate that coexistence is not solely determined by features of the numerically-dominant species. This results in a common framework for predicting, given any pair of species and knowledge of the relevant parameters, whether they will coexist, the mechanism by which they will do so, and the resultant spatial pattern of the community. Spatial coexistence arises from complementary combinations of traits in each

  6. Emergent neutrality drives phytoplankton species coexistence

    Science.gov (United States)

    Segura, Angel M.; Calliari, Danilo; Kruk, Carla; Conde, Daniel; Bonilla, Sylvia; Fort, Hugo

    2011-01-01

    The mechanisms that drive species coexistence and community dynamics have long puzzled ecologists. Here, we explain species coexistence, size structure and diversity patterns in a phytoplankton community using a combination of four fundamental factors: organism traits, size-based constraints, hydrology and species competition. Using a ‘microscopic’ Lotka–Volterra competition (MLVC) model (i.e. with explicit recipes to compute its parameters), we provide a mechanistic explanation of species coexistence along a niche axis (i.e. organismic volume). We based our model on empirically measured quantities, minimal ecological assumptions and stochastic processes. In nature, we found aggregated patterns of species biovolume (i.e. clumps) along the volume axis and a peak in species richness. Both patterns were reproduced by the MLVC model. Observed clumps corresponded to niche zones (volumes) where species fitness was highest, or where fitness was equal among competing species. The latter implies the action of equalizing processes, which would suggest emergent neutrality as a plausible mechanism to explain community patterns. PMID:21177680

  7. Species coexistence: macroevolutionary relationships and the contingency of historical interactions.

    Science.gov (United States)

    Germain, Rachel M; Weir, Jason T; Gilbert, Benjamin

    2016-03-30

    Evolutionary biologists since Darwin have hypothesized that closely related species compete more intensely and are therefore less likely to coexist. However, recent theory posits that species diverge in two ways: either through the evolution of 'stabilizing differences' that promote coexistence by causing individuals to compete more strongly with conspecifics than individuals of other species, or through the evolution of 'fitness differences' that cause species to differ in competitive ability and lead to exclusion of the weaker competitor. We tested macroevolutionary patterns of divergence by competing pairs of annual plant species that differ in their phylogenetic relationships, and in whether they have historically occurred in the same region or different regions (sympatric versus allopatric occurrence). For sympatrically occurring species pairs, stabilizing differences rapidly increased with phylogenetic distance. However, fitness differences also increased with phylogenetic distance, resulting in coexistence outcomes that were unpredictable based on phylogenetic relationships. For allopatric species, stabilizing differences showed no trend with phylogenetic distance, whereas fitness differences increased, causing coexistence to become less likely among distant relatives. Our results illustrate the role of species' historical interactions in shaping how phylogenetic relationships structure competitive dynamics, and offer an explanation for the evolution of invasion potential of non-native species. © 2016 The Author(s).

  8. Species coexistence in a changing world.

    Science.gov (United States)

    Valladares, Fernando; Bastias, Cristina C; Godoy, Oscar; Granda, Elena; Escudero, Adrián

    2015-01-01

    The consequences of global change for the maintenance of species diversity will depend on the sum of each species responses to the environment and on the interactions among them. A wide ecological literature supports that these species-specific responses can arise from factors related to life strategies, evolutionary history and intraspecific variation, and also from environmental variation in space and time. In the light of recent advances from coexistence theory combined with mechanistic explanations of diversity maintenance, we discuss how global change drivers can influence species coexistence. We revise the importance of both competition and facilitation for understanding coexistence in different ecosystems, address the influence of phylogenetic relatedness, functional traits, phenotypic plasticity and intraspecific variability, and discuss lessons learnt from invasion ecology. While most previous studies have focused their efforts on disentangling the mechanisms that maintain the biological diversity in species-rich ecosystems such as tropical forests, grasslands and coral reefs, we argue that much can be learnt from pauci-specific communities where functional variability within each species, together with demographic and stochastic processes becomes key to understand species interactions and eventually community responses to global change.

  9. Trophic position of coexisting krill species: a stable isotope approach

    DEFF Research Database (Denmark)

    Agersted, Mette Dalgaard; Bode, Antonio; Nielsen, Torkel Gissel

    2014-01-01

    Four krill species with overlapping functional biology coexist in Greenland waters. Here, we used stable isotopes to investigate and discuss their trophic role and mode of coexistence. Bulk carbon (δ13C) and nitrogen (δ15N) stable isotope analyses of Thysanoessa longicaudata, T. inermis, T. raschii...

  10. Coexistence induced by pollen limitation in flowering-plant species.

    OpenAIRE

    Ishii, R; Higashi, M

    2001-01-01

    We report a novel mechanism for species coexistence that does not invoke a trade-off relationship in the case of outbreeding flowering plants. Competition for pollination services may lead to interspecific segregation of the timing of flowering among plants. This, in turn, sets limits on the pollination services, which restrain the population growth of a competitively superior species, thereby allowing an inferior species to sustain its population in the habitat. This explains the often-obser...

  11. The relationship between species richness and ecosystem variability is shaped by the mechanism of coexistence.

    Science.gov (United States)

    Tredennick, Andrew T; Adler, Peter B; Adler, Frederick R

    2017-08-01

    Theory relating species richness to ecosystem variability typically ignores the potential for environmental variability to promote species coexistence. Failure to account for fluctuation-dependent coexistence may explain deviations from the expected negative diversity-ecosystem variability relationship, and limits our ability to predict the consequences of increases in environmental variability. We use a consumer-resource model to explore how coexistence via the temporal storage effect and relative nonlinearity affects ecosystem variability. We show that a positive, rather than negative, diversity-ecosystem variability relationship is possible when ecosystem function is sampled across a natural gradient in environmental variability and diversity. We also show how fluctuation-dependent coexistence can buffer ecosystem functioning against increasing environmental variability by promoting species richness and portfolio effects. Our work provides a general explanation for variation in observed diversity-ecosystem variability relationships and highlights the importance of conserving regional species pools to help buffer ecosystems against predicted increases in environmental variability. © 2017 John Wiley & Sons Ltd/CNRS.

  12. The coexistence of species La coexistencia de especies

    Directory of Open Access Journals (Sweden)

    CALEB E. GORDON

    2000-03-01

    Full Text Available This paper is a critical literature review on the topic of the coexistence of similar species within ecological communities. A conceptual framework is provided for dividing coexistence studies and concepts into three distinct time scales. The first six sections deal primarily with ecological-scale, or mesoscale coexistence, defined as coexistence in the classic sense of the competitive exclusion principle and Lotka-Volterra models, wherein interacting populations have had enough time to reach equilibrium. The first four sections briefly review resource partitioning studies and competitive coexistence models, and discuss the relative contributions of, and interaction between empirical and theoretical approaches to the problem of ecological-scale coexistence. The next two sections discuss the importance of biological trade-offs and the role of competition in structuring ecological communities. Based on compelling empirical evidence on both sides of the competition debate, a view of competition's role in structuring communities is proposed wherein the effects of competition are important but incomplete. The next section briefly reviews coexistence as it has been incorporated into habitat selection models, which represents coexistence at a finer time scale generated by the behavioral decisions of individual organisms. Linkages between this type of coexistence and mesoscale coexistence are discussed. Finally, a larger scale of coexistence is explored in which the assumptions of fixed niches, habitats, and species pools in communities are relaxed. This section links global and evolutionary species diversity literature to mesoscale ecological coexistence, focusing on the effects of ecosystem productivity and province size. Factors that govern diversity at large scales may be used to calibrate expectations and make predictions about mesoscale coexistence within particular communities. The study of diversity dynamics at geologic time scales suggests some

  13. Octocoral Species Assembly and Coexistence in Caribbean Coral Reefs.

    Science.gov (United States)

    Velásquez, Johanna; Sánchez, Juan A

    2015-01-01

    What are the determinant factors of community assemblies in the most diverse ecosystem in the ocean? Coral reefs can be divided in continental (i.e., reefs that develop on the continental shelf, including siliciclastic reefs) and oceanic (i.e., far off the continental shelf, usually on volcanic substratum); whether or not these habitat differences impose community-wide ecological divergence or species exclusion/coexistence with evolutionary consequences, is unknown. Studying Caribbean octocorals as model system, we determined the phylogenetic community structure in a coral reef community, making emphasis on species coexistence evidenced on trait evolution and environmental feedbacks. Forty-nine species represented in five families constituted the species pool from which a phylogenetic tree was reconstructed using mtDNA. We included data from 11 localities in the Western Caribbean (Colombia) including most reef types. To test diversity-environment and phenotype-environment relationships, phylogenetic community structure and trait evolution we carried out comparative analyses implementing ecological and evolutionary approaches. Phylogenetic inferences suggest clustering of oceanic reefs (e.g., atolls) contrasting with phylogenetic overdispersion of continental reefs (e.g., reefs banks). Additionally, atolls and barrier reefs had the highest species diversity (Shannon index) whereas phylogenetic diversity was higher in reef banks. The discriminant component analysis supported this differentiation between oceanic and continental reefs, where continental octocoral species tend to have greater calyx apertures, thicker branches, prominent calyces and azooxanthellate species. This analysis also indicated a clear separation between the slope and the remaining habitats, caused by the presence or absence of Symbiodinium. K statistic analysis showed that this trait is conserved as well as the branch shape. There was strong octocoral community structure with opposite diversity

  14. Octocoral Species Assembly and Coexistence in Caribbean Coral Reefs.

    Directory of Open Access Journals (Sweden)

    Johanna Velásquez

    Full Text Available What are the determinant factors of community assemblies in the most diverse ecosystem in the ocean? Coral reefs can be divided in continental (i.e., reefs that develop on the continental shelf, including siliciclastic reefs and oceanic (i.e., far off the continental shelf, usually on volcanic substratum; whether or not these habitat differences impose community-wide ecological divergence or species exclusion/coexistence with evolutionary consequences, is unknown.Studying Caribbean octocorals as model system, we determined the phylogenetic community structure in a coral reef community, making emphasis on species coexistence evidenced on trait evolution and environmental feedbacks. Forty-nine species represented in five families constituted the species pool from which a phylogenetic tree was reconstructed using mtDNA. We included data from 11 localities in the Western Caribbean (Colombia including most reef types. To test diversity-environment and phenotype-environment relationships, phylogenetic community structure and trait evolution we carried out comparative analyses implementing ecological and evolutionary approaches.Phylogenetic inferences suggest clustering of oceanic reefs (e.g., atolls contrasting with phylogenetic overdispersion of continental reefs (e.g., reefs banks. Additionally, atolls and barrier reefs had the highest species diversity (Shannon index whereas phylogenetic diversity was higher in reef banks. The discriminant component analysis supported this differentiation between oceanic and continental reefs, where continental octocoral species tend to have greater calyx apertures, thicker branches, prominent calyces and azooxanthellate species. This analysis also indicated a clear separation between the slope and the remaining habitats, caused by the presence or absence of Symbiodinium. K statistic analysis showed that this trait is conserved as well as the branch shape.There was strong octocoral community structure with opposite

  15. Species Coexistence in Nitrifying Chemostats: A Model of Microbial Interactions

    Directory of Open Access Journals (Sweden)

    Maxime Dumont

    2016-12-01

    Full Text Available In a previous study, the two nitrifying functions (ammonia oxidizing bacteria (AOB or nitrite-oxidizing bacteria (NOB of a nitrification reactor—operated continuously over 525 days with varying inputs—were assigned using a mathematical modeling approach together with the monitoring of bacterial phylotypes. Based on these theoretical identifications, we develop here a chemostat model that does not explicitly include only the resources’ dynamics (different forms of soluble nitrogen but also explicitly takes into account microbial inter- and intra-species interactions for the four dominant phylotypes detected in the chemostat. A comparison of the models obtained with and without interactions has shown that such interactions permit the coexistence of two competing ammonium-oxidizing bacteria and two competing nitrite-oxidizing bacteria in competition for ammonium and nitrite, respectively. These interactions are analyzed and discussed.

  16. Trait-fitness relationships determine how trade-off shapes affect species coexistence.

    Science.gov (United States)

    Ehrlich, Elias; Becks, Lutz; Gaedke, Ursula

    2017-12-01

    Trade-offs between functional traits are ubiquitous in nature and can promote species coexistence depending on their shape. Classic theory predicts that convex trade-offs facilitate coexistence of specialized species with extreme trait values (extreme species) while concave trade-offs promote species with intermediate trait values (intermediate species). We show here that this prediction becomes insufficient when the traits translate non-linearly into fitness which frequently occurs in nature, e.g., an increasing length of spines reduces grazing losses only up to a certain threshold resulting in a saturating or sigmoid trait-fitness function. We present a novel, general approach to evaluate the effect of different trade-off shapes on species coexistence. We compare the trade-off curve to the invasion boundary of an intermediate species invading the two extreme species. At this boundary, the invasion fitness is zero. Thus, it separates trait combinations where invasion is or is not possible. The invasion boundary is calculated based on measurable trait-fitness relationships. If at least one of these relationships is not linear, the invasion boundary becomes non-linear, implying that convex and concave trade-offs not necessarily lead to different coexistence patterns. Therefore, we suggest a new ecological classification of trade-offs into extreme-favoring and intermediate-favoring which differs from a purely mathematical description of their shape. We apply our approach to a well-established model of an empirical predator-prey system with competing prey types facing a trade-off between edibility and half-saturation constant for nutrient uptake. We show that the survival of the intermediate prey depends on the convexity of the trade-off. Overall, our approach provides a general tool to make a priori predictions on the outcome of competition among species facing a common trade-off in dependence of the shape of the trade-off and the shape of the trait

  17. A test of five mechanisms of species coexistence between rodents in ...

    African Journals Online (AJOL)

    A test of five mechanisms of species coexistence between rodents in a southern African savanna. M.R. Perrin, B.P. Kotler. Abstract. The operation of five different mechanisms of species coexistence in a community of rodents was examined in a semi-arid Kalahari savanna in southern Africa. The two most common species ...

  18. Rising temperature reduces divergence in resource use strategies in coexisting parasitoid species

    NARCIS (Netherlands)

    Le Lann, C.; Visser, Bertanne; Mériaux, M.; Moiroux, J.; van Baaren, J.; van Alphen, J.M.; Ellers, J.

    2014-01-01

    Coexistence of species sharing the same resources is often possible if species are phylogenetically divergent in resource acquisition and allocation traits, decreasing competition between them. Developmental and life-history traits related to resource use are influenced by environmental conditions

  19. Reciprocal Prioritization to Dietary Glycans by Gut Bacteria in a Competitive Environment Promotes Stable Coexistence

    Directory of Open Access Journals (Sweden)

    Yunus E. Tuncil

    2017-10-01

    Full Text Available When presented with nutrient mixtures, several human gut Bacteroides species exhibit hierarchical utilization of glycans through a phenomenon that resembles catabolite repression. However, it is unclear how closely these observed physiological changes, often measured by altered transcription of glycan utilization genes, mirror actual glycan depletion. To understand the glycan prioritization strategies of two closely related human gut symbionts, Bacteroides ovatus and Bacteroides thetaiotaomicron, we performed a series of time course assays in which both species were individually grown in a medium with six different glycans that both species can degrade. Disappearance of the substrates and transcription of the corresponding polysaccharide utilization loci (PULs were measured. Each species utilized some glycans before others, but with different priorities per species, providing insight into species-specific hierarchical preferences. In general, the presence of highly prioritized glycans repressed transcription of genes involved in utilizing lower-priority nutrients. However, transcriptional sensitivity to some glycans varied relative to the residual concentration in the medium, with some PULs that target high-priority substrates remaining highly expressed even after their target glycan had been mostly depleted. Coculturing of these organisms in the same mixture showed that the hierarchical orders generally remained the same, promoting stable coexistence. Polymer length was found to be a contributing factor for glycan utilization, thereby affecting its place in the hierarchy. Our findings not only elucidate how B. ovatus and B. thetaiotaomicron strategically access glycans to maintain coexistence but also support the prioritization of carbohydrate utilization based on carbohydrate structure, advancing our understanding of the relationships between diet and the gut microbiome.

  20. Interference competition as a mechanism of coexistence between two sympatric species of the grass shrimp Palaemonetes (Decapoda: Palaemonidae)

    Energy Technology Data Exchange (ETDEWEB)

    Thorp, J.H.

    1976-01-01

    Various theories have been developed to explain the puzzling coexistence of species which have broad niche overlap in critical resource utilization. The coexistence of two sympatric species of grass shrimp, Palaemonetes pugio Holthuis and p. vulgaris (Say), whose niches overlap with respect to space, food, and time, was examined in an experimental field and laboratory study. A seasonal fluctuation between sympatric and contiguous allopatric distribution of the two species of grass shrimp on natural shell, mud, and eelgrass substrata suggests that competition may be an important factor determining distribution of Palaemonetes. Field and laboratory experiments confirm that P. vulgaris can competitively displace P. pugio from the preferred shell substratum by interference competition but the tendency of grass shrimp to separate spatially in winter by bottom-depths (as in field enclosure cages) could have allowed both species to coexist on shell. Spatial separation by bottom-depth was not so evident in spring, since P. vulgaris apparently displaced P. pugio from shell to mud substratum. Occupancy of shell substratum is shown to be adaptive in that shell provides greater protection from predators than does mud. It is suggested that the spatial partitioning resulting from this interference competition promotes coexistence by reducing agonism while permitting efficient utilization of other common resources.

  1. Species coexistence and the superior ability of an invasive species to exploit a facilitation cascade habitat

    Directory of Open Access Journals (Sweden)

    Andrew H. Altieri

    2017-02-01

    Full Text Available Facilitation cascades generated by co-occurring foundation species can enhance the abundance and diversity of associated organisms. However, it remains poorly understood how differences among native and invasive species in their ability to exploit these positive interactions contribute to emergent patterns of community structure and biotic acceptance. On intertidal shorelines in New England, we examined the patterns of coexistence between the native mud crabs and the invasive Asian shore crab in and out of a facilitation cascade habitat generated by mid intertidal cordgrass and ribbed mussels. These crab species co-occurred in low intertidal cobbles adjacent to the cordgrass–mussel beds, despite experimental findings that the dominant mud crabs can kill and displace Asian shore crabs and thereby limit their successful recruitment to their shared habitat. A difference between the native and invasive species in their utilization of the facilitation cascade likely contributes to this pattern. Only the Asian shore crabs inhabit the cordgrass–mussel beds, despite experimental evidence that both species can similarly benefit from stress amelioration in the beds. Moreover, only Asian shore crabs settle in the beds, which function as a nursery habitat free of lethal mud crabs, and where their recruitment rates are particularly high (nearly an order of magnitude higher than outside beds. Persistence of invasive adult Asian shore crabs among the dominant native mud crabs in the low cobble zone is likely enhanced by a spillover effect of the facilitation cascade in which recruitment-limited Asian shore crabs settle in the mid intertidal cordgrass–mussel beds and subsidize their vulnerable populations in the adjacent low cobble zone. This would explain why the abundances of Asian shore crabs in cobbles are doubled when adjacent to facilitation cascade habitats. The propensity for this exotic species to utilize habitats created by facilitation cascades

  2. Ecology of the coexisting copepod species in Cochin backwaters

    Digital Repository Service at National Institute of Oceanography (India)

    Madhupratap, M.

    of the high saline species. The degree of ecological differentiation between them was not very clear. Probably the peculiarities of the estuarine system allowed them to survive as competitors, since it is conceivable that the competing species expand...

  3. Zealotry promotes coexistence in the rock-paper-scissors model of cyclic dominance

    Science.gov (United States)

    Verma, Gunjan; Chan, Kevin; Swami, Ananthram

    2015-11-01

    Cyclic dominance models, such as the classic rock-paper-scissors (RPS) game, have found real-world applications in biology, ecology, and sociology. A key quantity of interest in such models is the coexistence time, i.e., the time until at least one population type goes extinct. Much recent research has considered conditions that lengthen coexistence times in an RPS model. A general finding is that coexistence is promoted by localized spatial interactions (low mobility), while extinction is fostered by global interactions (high mobility). That is, there exists a mobility threshold which separates a regime of long coexistence from a regime of rapid collapse of coexistence. The key finding of our paper is that if zealots (i.e., nodes able to defeat others while themselves being immune to defeat) of even a single type exist, then system coexistence time can be significantly prolonged, even in the presence of global interactions. This work thus highlights a crucial determinant of system survival time in cyclic dominance models.

  4. Recruitment dynamics mediated by ungulate herbivory can affect species coexistence for tree seedling assemblages

    Directory of Open Access Journals (Sweden)

    Chi-Yu Weng

    2017-08-01

    Full Text Available The best-known mechanism that herbivory affects species coexistence of tree seedlings is negative density-dependency driven by specialist natural enemies. However, in a forest with intense herbivory by non-specialists, what causes a diversifying seedling bank if rare species do not benefit from negative density-dependency in dominant species? We hypothesize that generalist herbivores can cause unevenly distributed species-specific mortality, which mediates recruitment dynamics and therefore affects species coexistence. To answer this question, we conducted a fence-control experiment in a montane cloud forest, Taiwan, and found that herbivorous damages were mainly caused by ungulates, which are generalists. We explored ungulate herbivory effects on recruitment dynamics by censusing tree seedling dynamics for three years. We found that herbivorous damages by ungulates significantly cause seedling death, mostly at their early stage of establishment. The percentage of death caused by herbivory varied among species. In particular, nurse plants and seedling initial height help shade-tolerant species to persist under such intense herbivory. Whereas, deaths caused by other factors occurred more often in older seedlings, with a consistent low percentage among species. We then tested species coexistence maintenance by dynamic modelling under different scenarios of ungulate herbivory. Raising percentages of death by herbivory changes relative species abundances by suppressing light-demanding species and increasing shade-tolerant species. Density-dependent mortality immediately after bursts of recruitments can suppress dominance of abundant species. With ungulate herbivory, fluctuating recruitment further prevent rare species from apparent competition induced by abundant species. Such bio-processes can interact with ungulate herbivory so that long-term coexistence can be facilitated.

  5. Endangered Species and Natural Resource Exploitation: Extinction vs. Coexistence

    OpenAIRE

    Tsur, Yacov; Zemel, Amos

    1994-01-01

    The threat on the survival of animal species due to intensive use of natural resources is incorporated within resource management models, paying special attention to uncertainty regarding the conditions that lead to extinction. The manner in which the potential benefits forgone due to the species extinction (denoted extinction penalty) induce more conservative exploitation policies is studied in detail. When the extinction penalty is ignored, the optimal policy is to drive the resource stock ...

  6. Coexistence of three different Drosophila species by rescheduling ...

    Indian Academy of Sciences (India)

    Unknown

    gaster species group (Bock and Wheeler 1972) and in the ... pur fruit market, Bangalore (hereafter referred as Banga- ... F1 virgin flies were collected from each vial and sexed and kept in different vials with a density of 25 flies .... J. R. David group (see Morin et al. ..... different life history strategies – the fast developers die.

  7. Water-use strategies of six co-existing Mediterranean woody species during a summer drought

    NARCIS (Netherlands)

    Quero, J.L.; Sterck, F.J.; Martínez-Vilalta, J.; Villar, R.

    2011-01-01

    Drought stress is known to limit plant performance in Mediterranean-type ecosystems. We have investigated the dynamics of the hydraulics, gas exchange and morphology of six co-existing Mediterranean woody species growing under natural field conditions during a drought that continued during the

  8. Woody-Herbaceous Species Coexistence in Mulga Hillslopes: Modelling Structure and Function

    Science.gov (United States)

    Soltanjalili, M. J.; Saco, P. M.; Willgoose, G. R.

    2016-12-01

    The fundamental processes underlying the coexistence of woody and herbaceous species in arid and semi-arid areas have been a topic of intense research during the last few decades. Experimental and modelling studies have both supported and disputed alternative hypotheses explaining this phenomenon. Vegetation models including the key processes that drive coexistence can be used to understand vegetation pattern dynamics and structure under current climate conditions, and to predict changes under future conditions. Here we present work done towards linking the observations to modelling. The model captures woody-herbaceous coexistence along a rainfall gradient characteristic of typical conditions on Mulga ecosystems in Australia. The dynamic vegetation model simulates the spatial dynamics of overland flow, soil moisture and vegetation growth of two species. It incorporates key mechanisms for coexistence and pattern formation, including facilitation by evaporation reduction through shading, and infiltration feedbacks, local and non-local seed dispersal, competition for water uptake. Model outcomes, obtained including diflerent mechanisms, are qualitatively compared to typical vegetation cover patterns in the Australian Mulga bioregion where bush fire is very infrequent and the fate of vegetation cover is mostly determined by intra- and interspecies interactions. Through these comparisons, and by drawing on the large number of recent studies that have delivered new insights into the dynamics of such ecosystems, we identify main mechanisms that need an improved representation in the dynamic vegetation models. We show that a realistic parameterization of the model leads to results which are aligned with the observations reported in the literature. At the lower end of the rainfall gradient woody species coexist with herbaceous species within a sparse banded pattern, while at higher rainfall woody species tend to dominate the landscape.

  9. Environmental periodicity and the coexistence problem for two competing and dispersive species

    International Nuclear Information System (INIS)

    Elion-Mboussa, A.

    1994-11-01

    The dynamic behaviour of two competing and dispersive species in a heterogeneous space and periodically fluctuating environment is studied. Periodic environmental factors were incorporated into a non-linear reaction-diffusion model, through intrinsic demographic parameters of one of the two species sharing the same favourable space. Furthermore, it was assumed that the physical environmental factors do not have an effect on the growth rate of one of the species. An ecological example of these assumptions is a host- parasite system where parasite reproduction is strongly seasonal, while host populations remain insensitive to physical environmental factors that affect the parasite populations. However, the induced effect of physical environmental factors on the non-affected species was established by means of computer calculations. The periodic oscillations which over the time lead to competitive coexistence of both species with periodic forced oscillations have been shown. It was also shown that, in a periodic environment and under appropriate initial conditions, two competing and dispersive species can coexist when in a constant environment they could not coexist. (author). 25 refs, 12 figs

  10. Preferences for different nitrogen forms by coexisting plant species and soil microbes.

    Science.gov (United States)

    Harrison, Kathryn A; Bol, Roland; Bardgett, Richard D

    2007-04-01

    The growing awareness that plants might use a variety of nitrogen (N) forms, both organic and inorganic, has raised questions about the role of resource partitioning in plant communities. It has been proposed that coexisting plant species might be able to partition a limited N pool, thereby avoiding competition for resources, through the uptake of different chemical forms of N. In this study, we used in situ stable isotope labeling techniques to assess whether coexisting plant species of a temperate grassland (England, UK) display preferences for different chemical forms of N, including inorganic N and a range of amino acids of varying complexity. We also tested whether plants and soil microbes differ in their preference for different N forms, thereby relaxing competition for this limiting resource. We examined preferential uptake of a range of 13C15N-labeled amino acids (glycine, serine, and phenylalanine) and 15N-labeled inorganic N by coexisting grass species and soil microbes in the field. Our data show that while coexisting plant species simultaneously take up a variety of N forms, including inorganic N and amino acids, they all showed a preference for inorganic N over organic N and for simple over the more complex amino acids. Soil microbes outcompeted plants for added N after 50 hours, but in the long-term (33 days) the proportion of added 15N contained in the plant pool increased for all N forms except for phenylalanine, while the proportion in the microbial biomass declined relative to the first harvest. These findings suggest that in the longer-term plants become more effective competitors for added 15N. This might be due to microbial turnover releasing 15N back into the plant-soil system or to the mineralization and subsequent plant uptake of 15N transferred initially to the organic matter pool. We found no evidence that soil microbes preferentially utilize any of the N forms added, despite previous studies showing that microbial preferences for N forms

  11. Fungal communities in wheat grain show significant co-existence patterns among species

    DEFF Research Database (Denmark)

    Nicolaisen, M.; Justesen, A. F.; Knorr, K.

    2014-01-01

    identified as ‘core’ OTUs as they were found in all or almost all samples and accounted for almost 99 % of all sequences. The remaining OTUs were only sporadically found and only in small amounts. Cluster and factor analyses showed patterns of co-existence among the core species. Cluster analysis grouped...... the 21 core OTUs into three clusters: cluster 1 consisting of saprotrophs, cluster 2 consisting mainly of yeasts and saprotrophs and cluster 3 consisting of wheat pathogens. Principal component extraction showed that the Fusarium graminearum group was inversely related to OTUs of clusters 1 and 2....

  12. School-Family Partnership for Coexistence (SFPC) in the City of Acre: Promoting Arab and Jewish Parents' Role as Facilitators of Children's Literacy Development and as Agents of Coexistence

    Science.gov (United States)

    Zelniker, Tamar; Hertz-Lazarowitz, Rachel

    2005-01-01

    A two-year (1998-2000) School-Family Partnership for Coexistence (SFPC) programme was implemented in Acre, a mixed Jewish-Arab city in Israel, to promote parents' role as facilitators of their children literacy development and to empower parents to advance coexistence and inter-group relations. The SFPC program was part of a five-year (1995-2000)…

  13. The Environmental Education, as an Option to Promote the Ecological Coexistence

    Directory of Open Access Journals (Sweden)

    Betty Marleny Castillo Ávila

    2016-11-01

    Full Text Available The purpose of this research aims to develop an action plan in environmental education, as an ecologic option for the students of the Francisco Tamayo Technical School located in Barinitas parish, Bolívar municipality state Barinas. In this institution the students lack of an orientation and motivation about an action plan to promote the ecological coexistence. The nature of this study belongs to the qualitative approach of a participatory action research. On the other hand, this research was made in three phases: Phase I. Diagnosis, Phase II Programming, Phase III Conclusions and Proposals. The key people will be: (03 students, (03 teachers and (03 representatives. The technique of gathering information will be the deep interview and documents and actions view which show theoretical structures from the practice itself since so, it represents a better adaptation. The analysis techniques of information were categorization, triangulation and interpretation. Among the expected results are that the students become more sensitive and acquire knowledge related to ecological and environmental cohabitation from an interdisciplinary approach taking responsibility for attitude changes that the community needs to grow socially and economically.

  14. Functional equivalence, competitive hierarchy and facilitation determine species coexistence in highly invaded grasslands

    Czech Academy of Sciences Publication Activity Database

    Gross, N.; Liancourt, Pierre; Butters, R.; Ducan, R. P.; Hulme, P. E.

    2015-01-01

    Roč. 206, č. 1 (2015), s. 175-186 ISSN 0028-646X Institutional support: RVO:67985939 Keywords : biotic interactions * Coexistence * Community assembly Subject RIV: EH - Ecology, Behaviour Impact factor: 7.210, year: 2015

  15. Complementarity in nutrient foraging strategies of absorptive fine roots and arbuscular mycorrhizal fungi across 14 coexisting subtropical tree species.

    Science.gov (United States)

    Liu, Bitao; Li, Hongbo; Zhu, Biao; Koide, Roger T; Eissenstat, David M; Guo, Dali

    2015-10-01

    In most cases, both roots and mycorrhizal fungi are needed for plant nutrient foraging. Frequently, the colonization of roots by arbuscular mycorrhizal (AM) fungi seems to be greater in species with thick and sparsely branched roots than in species with thin and densely branched roots. Yet, whether a complementarity exists between roots and mycorrhizal fungi across these two types of root system remains unclear. We measured traits related to nutrient foraging (root morphology, architecture and proliferation, AM colonization and extramatrical hyphal length) across 14 coexisting AM subtropical tree species following root pruning and nutrient addition treatments. After root pruning, species with thinner roots showed more root growth, but lower mycorrhizal colonization, than species with thicker roots. Under multi-nutrient (NPK) addition, root growth increased, but mycorrhizal colonization decreased significantly, whereas no significant changes were found under nitrogen or phosphate additions. Moreover, root length proliferation was mainly achieved by altering root architecture, but not root morphology. Thin-root species seem to forage nutrients mainly via roots, whereas thick-root species rely more on mycorrhizal fungi. In addition, the reliance on mycorrhizal fungi was reduced by nutrient additions across all species. These findings highlight complementary strategies for nutrient foraging across coexisting species with contrasting root traits. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  16. Trait-based plant ecology: moving towards a unifying species coexistence theory : Features of the Special Section.

    Science.gov (United States)

    Escudero, Adrián; Valladares, Fernando

    2016-04-01

    Functional traits are the center of recent attempts to unify key ecological theories on species coexistence and assembling in populations and communities. While the plethora of studies on the role of functional traits to explain patterns and dynamics of communities has rendered a complex picture due to the idiosyncrasies of each study system and approach, there is increasing evidence on their actual relevance when aspects such as different spatial scales, intraspecific variability and demography are considered.

  17. Species of the Hoplias aff malabaricus complex (Characiformes: Erythrinidae: An investigation of coexistence in a Neotropical floodplain

    Directory of Open Access Journals (Sweden)

    Marília Hauser

    2012-02-01

    Full Text Available This study assessed the coexistence of three species of thraira present in the Upper Paraná River floodplain, using population structure as an investigation tool. The species were designated as: Hoplias sp. 1, introduced after the construction of the Itaipu reservoir, and Hoplias sp. 2 and Hoplias sp. 3, native species that have been identified as Hoplias aff. malabaricus. We tested the hypothesis that those species in fact differ from each other in respect of population abundance, sex ratio, relative frequency of adults and juveniles, length structure and weight-length relationship. Additionally, possible effects of the flood pulse on the first four of these parameters were investigated. Samples were collected quarterly from March 2006 to December 2007 from nine collection sites on the floodplain. Hoplias sp. 1 presented a greater balance of sex ratio and length structures over the seasons, as well as a higher allometric coefficient. The population attributes of Hoplias sp. 2 and Hoplias sp. 3 showed a high responsiveness to hydrological seasonality, indicating that these species exploit available resources in a conspicuous flood period with greater efficiency. These differences, beyond reflecting possible mechanisms that allow closely related species to coexist, indicate the importance of understanding the life strategies adopted by each species which, as part of a complex system, are considered key elements of the aquatic community structure in the region, providing important information for habitat management and biodiversity conservation.

  18. Coexistence of two freshwater turtle species along a Mediterranean stream: The role of spatial and temporal heterogeneity

    Science.gov (United States)

    Segurado, Pedro; Figueiredo, Diogo

    2007-09-01

    In the Iberian Peninsula the European pond turtle ( Emys orbicularis) and the Mediterranean pond turtle ( Mauremys leprosa) share many freshwater habitats, in particular Mediterranean streams. Whether and how these two species divide space within those habitats is poorly known in part due to the very low abundance of E. orbicularis at most syntopic sites. The spatial coexistence of these two species was studied along a 1.3 km reach of a typical Mediterranean stream based on data from trapping sessions and basking counts. The effect of the hydrological regime on differences in space use between species was also assessed. Spatial associations between species and between each species and microhabitat descriptors were estimated using a permutation procedure to account for spatial autocorrelation. Differences in the use of space were also estimated using a resample technique to account for the small sample sizes of E. orbicularis. Results indicate that E. orbicularis shows a preference for temporary, shallow, well vegetated and sandy reaches, while M. leprosa is less selective regarding microhabitat. Differences between E. orbicularis and juveniles of M. leprosa were less obvious. The high spatial heterogeneity of Mediterranean streams may be responsible for the persistence of viable populations of E. orbicularis as well as favouring the coexistence of the two turtle species. Therefore, stream habitat management and conservation plans for E. orbicularis should give priority to the maintenance of high levels of heterogeneity along Mediterranean streams.

  19. Nest site selection and breeding success in three Turdus thrush species coexisting in an urban environment

    Czech Academy of Sciences Publication Activity Database

    Mikula, P.; Hromada, M.; Albrecht, Tomáš; Tryjanowski, P.

    2014-01-01

    Roč. 49, č. 1 (2014), s. 83-92 ISSN 0001-6454 Institutional support: RVO:68081766 Keywords : breeding success * coexistence * nest-habitat partitioning * nest site selection * predation * synurbization * urban habitat * thrushes Subject RIV: EG - Zoology Impact factor: 0.745, year: 2014

  20. Solar Radiation Determines Site Occupancy of Coexisting Tropical and Temperate Deer Species Introduced to New Zealand Forests.

    Directory of Open Access Journals (Sweden)

    Robert B Allen

    Full Text Available Assemblages of introduced taxa provide an opportunity to understand how abiotic and biotic factors shape habitat use by coexisting species. We tested hypotheses about habitat selection by two deer species recently introduced to New Zealand's temperate rainforests. We hypothesised that, due to different thermoregulatory abilities, rusa deer (Cervus timorensis; a tropical species would prefer warmer locations in winter than red deer (Cervus elaphus scoticus; a temperate species. Since adult male rusa deer are aggressive in winter (the rut, we also hypothesised that rusa deer and red deer would not use the same winter locations. Finally, we hypothesised that in summer both species would prefer locations with fertile soils that supported more plant species preferred as food. We used a 250 × 250 m grid of 25 remote cameras to collect images in a 100-ha montane study area over two winters and summers. Plant composition, solar radiation, and soil fertility were also determined for each camera location. Multiseason occupancy models revealed that direct solar radiation was the best predictor of occupancy and detection probabilities for rusa deer in winter. Multistate, multiseason occupancy models provided strong evidence that the detection probability of adult male rusa deer was greater in winter and when other rusa deer were present at a location. Red deer mostly vacated the study area in winter. For the one season that had sufficient camera images of both species (summer 2011 to allow two-species occupancy models to be fitted, the detection probability of rusa deer also increased with solar radiation. Detection probability also varied with plant composition for both deer species. We conclude that habitat use by coexisting tropical and temperate deer species in New Zealand likely depends on the interplay between the thermoregulatory and behavioural traits of the deer and the abiotic and biotic features of the habitat.

  1. Trade-off between light interception efficiency and light use efficiency: implications for species coexistence in one-sided light competition

    NARCIS (Netherlands)

    Onoda, Y.; Saluñga, J.B.; Akutsu, K.; Aiba, S.I.; Yahara, T.; Anten, N.P.R.

    2014-01-01

    1. Taller plant species can pre-empt solar energy and suppress growth of subordinate species in vegetation stands, which is described through one-sided competition. Yet, in much of the world’s vegetation species of different statures coexist. This study aims to clarify the mechanisms underlying this

  2. Speciation, diversification, and coexistence of sessile species that compete for space

    DEFF Research Database (Denmark)

    Mitarai, Namiko; Heinsalu, Els; Sneppen, Kim

    2014-01-01

    Speciation, diversification, and competition between species challenge the stability of complex ecosystems. Laboratory experiments often focus on one or two species competing under conditions where they may grow exponentially. Field studies, in contrast, emphasize multi-species communities...... appear due to immigration from outside of the considered ecosystem. The species self-organize their spatial distribution through competitive interactions to create many patches, implicitly protecting each other from competitively superior species, and speciation in each patch leads the system to high...

  3. Phylogenetically poor plant communities receive more alien species, which more easily coexist with natives

    NARCIS (Netherlands)

    Gerhold, P.; Pärtel, M.; Tackenberg, O.; Hennekens, S.M.; Bartish, I.; Schaminee, J.H.J.; Fergus, A.J.F.; Ozinga, W.A.; Prinzing, A.

    2011-01-01

    Alien species can be a major threat to ecological communities, but we do not know why some community types allow the entry of many more alien species than do others. Here, for the first time, we suggest that evolutionary diversity inherent to the constituent species of a community may determine its

  4. Tree competition and species coexistence in a Quercus--Betula forest in the Dongling Mountains in northern China

    Science.gov (United States)

    Hou, Ji-hua; Mi, Xiang-cheng; Liu, Can-ran; Ma, Ke-ping

    2006-09-01

    The population size structure, growth dynamics and mode of competition among adult trees (≥ 4 cm DBH) of six abundant tree species in a 5 ha study plot of a temperate deciduous forest in the Dongling Mountains in northern China were investigated using diffusion and growth dynamics models. In the year of 2000, two dominant species, Quercus liaotungensis and Betula dahurica accounted for ca. 68.69% of the total basal area and 52.71% of the total density of adult plants. Q. liaotungensis, Populus davidiana and Acer mono exhibited inverse J-shaped DBH distributions whereas Betula dahurica, B. platyphylla and Salix caprea had unimodal DBH distributions. One-sided interspecific competition was detected between some species combinations at the scale of the 5 ha study plot, and the competitive effect was mainly size-dependent rather than from species-specific interactions with large individuals in the canopy layer out competing smaller individuals in the understory. Symmetric competition was found between Q. liaotungensis and A. mono only. However, considering the straight line relationship of G ( t, x) - √{D(t, x)}, which suggests that competitive asymmetry is very low or absent, combined with the relatively low mortality of trees with a DBH larger than 4 cm, we speculate that asymmetric interspecific competition was not important in structuring this tree community. Regeneration characteristics of each species are most likely important in regulating species coexistence and stand dynamics in this forest.

  5. Patterns of coexistence of two species of freshwater turtles are affected by spatial scale

    DEFF Research Database (Denmark)

    Segurado, P.; Kunin, W.E.; Filipe, A.F.

    2012-01-01

    Inferring biotic interactions from the examination of patterns of species occurrences has been a central tenet in community ecology, and it has recently gained interest in the context of single-species distribution modelling. However, understanding of how spatial extent and grain size affect such...

  6. Coexistence and succession of copepod species in the Mandovi and Zuari estuaries, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.

    Observations were made on the copepod species association and succession at six stations in the Mandovi-Zuari estuarine system of Goa, India. A total of 55 species belonging to 25 genera and 18 families were encountered in the surface collections...

  7. Multiple factors contribute to reproductive isolation between two co-existing Habenaria species (Orchidaceae.

    Directory of Open Access Journals (Sweden)

    Wenliu Zhang

    Full Text Available Reproductive isolation is a key feature that forms barriers to gene flow between distinct plants. In orchids, prezygotic reproductive isolation has been considered to be strong, because their associations with highly specific pollinators. In this study, the reproductive ecology and reproductive isolation of two sympatric Habenaria species, H. davidii and H. fordii, was investigated by floral phenology and morphology, hand-pollination experiments and visitor observation in southwest China. The two species were dependent on insects for pollination and completely self-compatible. A number of factors have been identified to limit gene flow between the two species and achieved full reproductive isolation. Ecogeographic isolation was a weak barrier. H. fordii and H. davidii had completely overlapped flowering periods, and floral morphology plays an important role in floral isolation. The two species shared the same hawkmoth pollinator, Cechenena lineosa, but the pollinaria of the two orchids were attached on different body parts of pollinators. Prezygotic isolation was not complete, but the interspecific pollination treatments of each species resulted in no seed sets, indicating that unlike many other orchid species, in which the postzygotic reproductive isolation is very weak or complete absence, the post-zygotic isolation strongly acted in the stage of seed production between two species. The results illustrate the reproductive isolation between two species involves multiple plant life-history stages and a variety of reproductive barriers can contribute to overall isolation.

  8. Patterns of resource exploitation in four coexisting globeflower fly species ( Chiastocheta sp.)

    Science.gov (United States)

    Pompanon, François; Pettex, Emeline; Després, Laurence

    2006-03-01

    Life history and spatio-temporal patterns of resource utilisation were characterised in four Chiastocheta (Diptera: Anthomyiidae) species, whose larvae compete as seed predators on Trollius europaeus fruits. Interspecific co-occurrence was observed in 80% of the resource patches (= Trollius fruits) in the two communities studied. Isolated larvae from all species had a similar food intake, but differed in development time and size at emergence. Different species exhibit contrasting resource exploitation strategies with specific mining patterns and a partial temporal shift. Two species exhibited particularly singular strategies. C. rotundiventris escaped from strong interactions with other species because it was the first species to develop and the only one to exploit the central pith of Trollius fruits. The key role of this species as the main pollinator of the host-plant appears to be a by-product of constraints imposed by occupying a restricted niche. Although the resource is ephemeral due to seed dispersal, C. dentifera, the last species to oviposit, is not disadvantaged because it has a short development time and rapid food intake. The different patterns can partly explain the stability of Chiastocheta communities, but do not prevent competition to occur at high larval densities.

  9. Nonrandom community assembly and high temporal turnover promote regional coexistence in tropics but not temperate zone.

    Science.gov (United States)

    Freestone, Amy L; Inouye, Brian D

    2015-01-01

    A persistent challenge for ecologists is understanding the ecological mechanisms that maintain global patterns of biodiversity, particularly the latitudinal diversity gradient of peak species richness in the tropics. Spatial and temporal variation in community composition contribute to these patterns of biodiversity, but how this variation and its underlying processes change across latitude remains unresolved. Using a model system of sessile marine invertebrates across 25 degrees of latitude, from the temperate zone to the tropics, we tested the prediction that spatial and temporal patterns of taxonomic richness and composition, and the community assembly processes underlying these patterns, will differ across latitude. Specifically, we predicted that high beta diversity (spatial variation in composition) and high temporal turnover contribute to the high species richness of the tropics. Using a standardized experimental approach that controls for several confounding factors that hinder interpretation of prior studies, we present results that support our predictions. In the temperate zone, communities were more similar across spatial scales from centimeters to tens of kilometers and temporal scales up to one year than at lower latitudes. Since the patterns at northern latitudes were congruent with a null model, stochastic assembly processes are implicated. In contrast, the communities in the tropics were a dynamic spatial and temporal mosaic, with low similarity even across small spatial scales and high temporal turnover at both local and regional scales. Unlike the temperate zone, deterministic community assembly processes such as predation likely contributed to the high beta diversity in the tropics. Our results suggest that community assembly processes and temporal dynamics vary across latitude and help structure and maintain latitudinal patterns of diversity.

  10. Growth and stable isotope signals associated with drought-related mortality in saplings of two coexisting pine species.

    Science.gov (United States)

    Herrero, Asier; Castro, Jorge; Zamora, Regino; Delgado-Huertas, Antonio; Querejeta, José I

    2013-12-01

    Drought-induced events of massive tree mortality appear to be increasing worldwide. Species-specific vulnerability to drought mortality may alter patterns of species diversity and affect future forest composition. We have explored the consequences of the extreme drought of 2005, which caused high sapling mortality (approx. 50 %) among 10-year-old saplings of two coexisting pine species in the Mediterranean mountains of Sierra Nevada (Spain): boreo-alpine Pinus sylvestris and Mediterranean P. nigra. Sapling height growth, leaf δ(13)C and δ(18)O, and foliar nitrogen concentration in the four most recent leaf cohorts were measured in dead and surviving saplings. The foliar isotopic composition of dead saplings (which reflects time-integrated leaf gas-exchange until mortality) displayed sharp increases in both δ(13)C and δ(18)O during the extreme drought of 2005, suggesting an important role of stomatal conductance (g(s)) reduction and diffusional limitations to photosynthesis in mortality. While P. nigra showed decreased growth in 2005 compared to the previous wetter year, P. sylvestris maintained similar growth levels in both years. Decreased growth, coupled with a sharper increase in foliar δ(18)O during extreme drought in dead saplings, indicate a more conservative water use strategy for P. nigra. The different physiological behavior of the two pine species in response to drought (further supported by data from surviving saplings) may have influenced 2005 mortality rates, which contributed to 2.4-fold greater survival for P. nigra over the lifespan of the saplings. This species-specific vulnerability to extreme drought could lead to changes in dominance and distribution of pine species in Mediterranean mountain forests.

  11. Possible mechanisms for the coexistence of congeneric (Pourouma, Cecropiaceae) Amazonian tree species

    DEFF Research Database (Denmark)

    Magård, Else

    2002-01-01

    The distribution, architecture, and foliar pest damage of ten species of Pourouma (Cecropiaceae) were investigated in a 50-ha plot of old-growth tropical rainforest in the Yasuní National Park, Ecuador. Individuals were censused and ecological and architectural data recorded along three 500 x 20 ...

  12. Phylogenetically poor plant communities receive more alien species, which more easily coexist with natives

    Czech Academy of Sciences Publication Activity Database

    Gerhold, P.; Pärtel, M.; Tackenberg, O.; Hennekens, S.M.; Bartish, Igor; Schaminée, J.H.J.; Fergus, A. J. F.; Ozinga, W.A.; Prinzing, A.

    2011-01-01

    Roč. 177, č. 5 (2011), s. 68-680 ISSN 0003-0147 Institutional research plan: CEZ:AV0Z60050516 Keywords : species richness * phylogenetic diversity * invasions Subject RIV: EF - Botanics Impact factor: 4.725, year: 2011

  13. One Year in the Lower St. Lawrence Estuary: Feeding Niche Separation of Two Co-existing Krill Species

    Science.gov (United States)

    Winkler, G.; Cabrol, J.; Sage, R.; Nozais, C.; Tremblay, R.; Starr, M.

    2016-02-01

    The lower St. Lawrence estuary (LSLE) is influenced by river discharge and saltwater inflow. Together with arctic water inflow and ice cover in winter a strong stratification occurs resulting in a cold intermediate layer (CIL) from spring to autumn. This stratification provides thermal habitats. Here, we focus on two krill species Thysanoessa raschii and Meganyctiphanes norvegica that aggregate in the CIL and the warmer deep water layer, respectively. Both species are known to migrate into the surface layer to feed and thus transfering energy through the food web by linking lower with higher trophic levels. However, their specific feeding biology and trophic interactions are poorly understood. We tested the following hypotheses: (1) the diets vary throughout the season depending on food availability, (2) similar to thermal habitat separation, trophic niche separation between T. raschii and M. norvegica occurs, characterized by herbivory in T. raschii and carnivory in M. norvegica. Trophic position and feeding behavior of theses krill populations were monitored throughout one year 2014-2015 using a stable isotope approach. The two species showed a seasonal shift in their trophic position being on a higher trophic level in summer than in spring and autumn, which did not correspond to phytoplankton or zooplankton availability. Within the trophic space of carbon and nitrogen stable isotopes M. norvegica showed a relatively stable position, whereas T. raschii covered a much larger space throughout the year. M. norvegica was always positioned at a higher trophic level than T. raschii. Results of a stable isotope mixing model (SIAR) revealed 50% phytoplankton and 50% copepods in the diet of M. norvegica, while T. raschii showed a higher proportion of ca. 70% phytoplankton in its diet. Both species exploited several trophic levels, but in different proportions, thereby minimizing diet overlap, suggesting a further mechanism to enhance stable co-existence of these krill

  14. Do competitive interactions in dry heathlands explain plant abundance patterns and species coexistence?

    DEFF Research Database (Denmark)

    Ransijn, Johannes; Damgaard, Christian; Schmidt, Inger K

    2015-01-01

    Plant community patterns in space and time may be explained by the interactions between competing plant species. The presented study investigates this in a nutrient and species poor ecosystem. The study presents a methodology for inferring competitive interactions from yearly vegetation inventories...... to predict the community dynamics of C. vulgaris and D. flexuosa. This was compared with the observed plant community structure at 198 Danish dry heathland sites. Interspecific competition will most likely lead to competitive exclusion of D. flexuosa at the observed temporal and spatial scale...... and uses this to assess the outcome of competitive interactions and to predict community patterns and dynamics in a Northwest-European dry heathland. Inferred competitive interactions from five consecutive years of measurements in permanent vegetation frames at a single dry heathland site were used...

  15. CONSERVATION PROGRAMS THAT PROMOTE INVASIVE SPECIES

    Science.gov (United States)

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

  16. The promotion effect of coexisting hygroscopic composition on the reaction between oxalic acid and calcite during humidifying process

    Science.gov (United States)

    Ma, Q.; He, H.

    2012-12-01

    Internally mixed oxalic acid with mineral dust has been frequently detected in field measurements (Sullivan and Prather, 2007; Wang et al., 2012; Yang et al., 2009). Meanwhile, Furukawa and Takahashi (Furukawa and Takahashi, 2011) found that most of the oxalic acid in mineral mixture is present as metal oxalate complexes in the aerosols, however, the formation mechanism of these complexes is not well known. It was reported that cloud process of H2C2O4/CaCO3 mixture could lead to the formation of calcium oxalate (Gierlus et al., 2012). Recently, we used Raman spectroscopy to investigate the hygroscopic behavior of H2C2O4/CaCO3 mixture below saturation condition as well as the effect of coexisting hygroscopic compositions, e.g. Ca(NO3)2, NaCl, NH4NO3, and (NH4)2SO4. It was found that there was no interaction between H2C2O4 and calcite without third component during humidifying process under ambient condition. In contrast, the presence of coexisting Ca(NO)3, NaCl, or NH4NO3 could promote the reaction between H2C2O4 and calcite by providing an aqueous circumstance after deliquescence, resulting in the formation of calcium oxalate hydrates. Moreover, substitution of strong acid (HNO3) by medium acid (H2C2O4) occurred when water vapor was absorbed in Ca(NO3)2/H2C2O4 mixture (Ma and He, 2012). As for (NH4)2SO4, there existed a competition effect between (NH4)2SO4 and H2C2O4 for the reaction with CaCO3. CaCO3 was preferentially reacted with (NH4)2SO4 to form gypsum in the solution, while the residual NH4+ and C2O42- ions were bonded to (NH4)2C2O4 after efflorescence. These results implies a potential formation pathway of metal oxalate complexes in the atmosphere and also suggests that synergistic effect between different constituents in humidifying process of mixed particles should be considered in future hygroscopic behavior studies.

  17. On the reasons that natural regeneration is important for species coexistence in tropical forests

    Directory of Open Access Journals (Sweden)

    Natalia Norden

    2014-12-01

    Full Text Available Plant regeneration plays a critical role in the maintenance of species diversity in tropical rainforests. This is a multistage process, including seed production, dispersal, germination and subsequent seedling establishment. All these stages represent major bottlenecks in plant demography, as early stages in the plant cycle (seeds and seedlings are the most vulnerable to environmental hazards, and are therefore subject to high mortality risks. The outcome of these ecological filters will determine not only seedling spatial distribution, but also the potential area of tree distribution. Seed dispersal and subsequent seedling establishment therefore play a critical role in the structuring of tree communities. Here, I review the main four ecological processes driving seedling recruitment in tropical forests. First, dispersal limitation is the failure of seeds to reach suitable microsites for seedling establishment. Once this filter is overcome, environmental factors can considerably affect seedling spatial distribution. Temporal fluctuations in these processes result in an important variation in recruitment success over time, and add a stochastic component to seedling regeneration. Finally, negative-density dependence regulates species relative abundance in the seedling layer by limiting conspecific recruitment through the attack of pathogen, fungi and herbivores.

  18. Differential growth responses to water balance of coexisting deciduous tree species are linked to wood density in a Bolivian tropical dry forest.

    Science.gov (United States)

    Mendivelso, Hooz A; Camarero, J Julio; Royo Obregón, Oriol; Gutiérrez, Emilia; Toledo, Marisol

    2013-01-01

    A seasonal period of water deficit characterizes tropical dry forests (TDFs). There, sympatric tree species exhibit a diversity of growth rates, functional traits, and responses to drought, suggesting that each species may possess different strategies to grow under different conditions of water availability. The evaluation of the long-term growth responses to changes in the soil water balance should provide an understanding of how and when coexisting tree species respond to water deficit in TDFs. Furthermore, such differential growth responses may be linked to functional traits related to water storage and conductance. We used dendrochronology and climate data to retrospectively assess how the radial growth of seven coexisting deciduous tree species responded to the seasonal soil water balance in a Bolivian TDF. Linear mixed-effects models were used to quantify the relationships between basal area increment and seasonal water balance. We related these relationships with wood density and sapwood production to assess if they affect the growth responses to climate. The growth of all species responded positively to water balance during the wet season, but such responses differed among species as a function of their wood density. For instance, species with a strong growth response to water availability averaged a low wood density which may facilitate the storage of water in the stem. By contrast, species with very dense wood were those whose growth was less sensitive to water availability. Coexisting tree species thus show differential growth responses to changes in soil water balance during the wet season. Our findings also provide a link between wood density, a trait related to the ability of trees to store water in the stem, and wood formation in response to water availability.

  19. Differential growth responses to water balance of coexisting deciduous tree species are linked to wood density in a Bolivian tropical dry forest.

    Directory of Open Access Journals (Sweden)

    Hooz A Mendivelso

    Full Text Available A seasonal period of water deficit characterizes tropical dry forests (TDFs. There, sympatric tree species exhibit a diversity of growth rates, functional traits, and responses to drought, suggesting that each species may possess different strategies to grow under different conditions of water availability. The evaluation of the long-term growth responses to changes in the soil water balance should provide an understanding of how and when coexisting tree species respond to water deficit in TDFs. Furthermore, such differential growth responses may be linked to functional traits related to water storage and conductance. We used dendrochronology and climate data to retrospectively assess how the radial growth of seven coexisting deciduous tree species responded to the seasonal soil water balance in a Bolivian TDF. Linear mixed-effects models were used to quantify the relationships between basal area increment and seasonal water balance. We related these relationships with wood density and sapwood production to assess if they affect the growth responses to climate. The growth of all species responded positively to water balance during the wet season, but such responses differed among species as a function of their wood density. For instance, species with a strong growth response to water availability averaged a low wood density which may facilitate the storage of water in the stem. By contrast, species with very dense wood were those whose growth was less sensitive to water availability. Coexisting tree species thus show differential growth responses to changes in soil water balance during the wet season. Our findings also provide a link between wood density, a trait related to the ability of trees to store water in the stem, and wood formation in response to water availability.

  20. Differential Growth Responses to Water Balance of Coexisting Deciduous Tree Species Are Linked to Wood Density in a Bolivian Tropical Dry Forest

    Science.gov (United States)

    Mendivelso, Hooz A.; Camarero, J. Julio; Royo Obregón, Oriol; Gutiérrez, Emilia; Toledo, Marisol

    2013-01-01

    A seasonal period of water deficit characterizes tropical dry forests (TDFs). There, sympatric tree species exhibit a diversity of growth rates, functional traits, and responses to drought, suggesting that each species may possess different strategies to grow under different conditions of water availability. The evaluation of the long-term growth responses to changes in the soil water balance should provide an understanding of how and when coexisting tree species respond to water deficit in TDFs. Furthermore, such differential growth responses may be linked to functional traits related to water storage and conductance. We used dendrochronology and climate data to retrospectively assess how the radial growth of seven coexisting deciduous tree species responded to the seasonal soil water balance in a Bolivian TDF. Linear mixed-effects models were used to quantify the relationships between basal area increment and seasonal water balance. We related these relationships with wood density and sapwood production to assess if they affect the growth responses to climate. The growth of all species responded positively to water balance during the wet season, but such responses differed among species as a function of their wood density. For instance, species with a strong growth response to water availability averaged a low wood density which may facilitate the storage of water in the stem. By contrast, species with very dense wood were those whose growth was less sensitive to water availability. Coexisting tree species thus show differential growth responses to changes in soil water balance during the wet season. Our findings also provide a link between wood density, a trait related to the ability of trees to store water in the stem, and wood formation in response to water availability. PMID:24116001

  1. Two co-existing germline mutations P53 V157D and PMS2 R20Q promote tumorigenesis in a familial cancer syndrome.

    Science.gov (United States)

    Wang, Zuoyun; Sun, Yihua; Gao, Bin; Lu, Yi; Fang, Rong; Gao, Yijun; Xiao, Tian; Liu, Xin-Yuan; Pao, William; Zhao, Yun; Chen, Haiquan; Ji, Hongbin

    2014-01-01

    Germline mutations are responsible for familial cancer syndromes which account for approximately 5-10% of all types of cancers. These mutations mainly occur at tumor suppressor genes or genome stability genes, such as DNA repair genes. Here we have identified a cancer predisposition family, in which eight members were inflicted with a wide spectrum of cancer including one diagnosed with lung cancer at 22years old. Sequencing analysis of tumor samples as well as histologically normal specimens identified two germline mutations co-existing in the familial cancer syndrome, the mutation of tumor suppressor gene P53 V157D and mismatch repair gene PMS2 R20Q. We further demonstrate that P53 V157D and/or PMS2 R20Q mutant promotes lung cancer cell proliferation. These two mutants are capable of promoting colony formation in soft agar as well as tumor formation in transgenic drosophila system. Collectively, these data have uncovered the important role of co-existing germline P53 and PMS2 mutations in the familial cancer syndrome development. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  2. Geoecohydrological mechanisms couple soil and leaf water dynamics and facilitate species coexistence in shallow soils of a tropical semiarid mixed forest.

    Science.gov (United States)

    Rodríguez-Robles, Ulises; Arredondo, J Tulio; Huber-Sannwald, Elisabeth; Vargas, Rodrigo

    2015-07-01

    Trees growing on shallow rocky soils must have exceptional adaptations when underlying weathered bedrock has no deep fractures for water storage. Under semiarid conditions, hydrology of shallow soils is expected to decouple from plant hydrology, as soils dry out as a result of rapid evaporation and competition for water increases between coexisting tree species. Gas exchange and plant-water relations were monitored for 15 months for Pinus cembroides and Quercus potosina tree species in a tropical semiarid forest growing on c. 20-cm-deep soils over impermeable volcanic bedrock. Soil and leaf water potential maintained a relatively constant offset throughout the year in spite of high intra-annual fluctuations reaching up to 5 MPa. Thus, hydrology of shallow soils did not decouple from hydrology of trees even in the driest period. A combination of redistribution mechanisms of water stored in weathered bedrock and hypodermic flow accessible to oak provided the source of water supply to shallow soils, where most of the actively growing roots occurred. This study demonstrates a unique geoecohydrological mechanism that maintains a tightly coupled hydrology between shallow rocky soils and trees, as well as species coexistence in this mixed forest, where oak facilitates water access to pine. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  3. Fiber mediated receptor masking in non-infected bystander cells restricts adenovirus cell killing effect but promotes adenovirus host co-existence.

    Directory of Open Access Journals (Sweden)

    Johan Rebetz

    Full Text Available The basic concept of conditionally replicating adenoviruses (CRAD as oncolytic agents is that progenies generated from each round of infection will disperse, infect and kill new cancer cells. However, CRAD has only inhibited, but not eradicated tumor growth in xenograft tumor therapy, and CRAD therapy has had only marginal clinical benefit to cancer patients. Here, we found that CRAD propagation and cancer cell survival co-existed for long periods of time when infection was initiated at low multiplicity of infection (MOI, and cancer cell killing was inefficient and slow compared to the assumed cell killing effect upon infection at high MOI. Excessive production of fiber molecules from initial CRAD infection of only 1 to 2% cancer cells and their release prior to the viral particle itself caused a tropism-specific receptor masking in both infected and non-infected bystander cells. Consequently, the non-infected bystander cells were inefficiently bound and infected by CRAD progenies. Further, fiber overproduction with concomitant restriction of adenovirus spread was observed in xenograft cancer therapy models. Besides the CAR-binding Ad4, Ad5, and Ad37, infection with CD46-binding Ad35 and Ad11 also caused receptor masking. Fiber overproduction and its resulting receptor masking thus play a key role in limiting CRAD functionality, but potentially promote adenovirus and host cell co-existence. These findings also give important clues for understanding mechanisms underlying the natural infection course of various adenoviruses.

  4. Do species differ in their ability to coexist with the dominant alien Lupinus polyphyllus? A comparison between two distinct invaded ranges and a native range

    Directory of Open Access Journals (Sweden)

    Martin Hejda

    2013-06-01

    Full Text Available The community-level impacts of invasive plants are likely to vary depending on the character of native species of the target communities and their ability to thrive within the stands of the dominant alien invader. Therefore, I examined the response of native species richness to the cover of the dominant alien Lupinus polyphyllus in two distinct invaded ranges: Czech Republic (Central Europe and New Zealand. I compared the relation between native species richness and the cover of the dominant alien L. polyphyllus with that in its native range, Pacific Northwest, USA.In the native range, I found no response of native species richness to the cover of L. polyphyllus. In the Czech Republic (central Europe, the richness of native species related to it negativelly, but the relation was only marginally significant. Contrary to that, the richness of species native to New Zealand related to the cover of L. polyphyllus strongly negatively and the negative relation was significantly stronger than that of species native to Europe.Of the two invaded ranges, species native to New Zealand have been documented to be much more vulnerable to the conditions associated with the invasion and dominance of L. polyphyllus, compared to species native to central Europe. This principle has been shown both across these two invaded ranges and in New Zealand, where the aliens of european origin successfully coexist with the dominant invasive alien L. polyphyllus. Similarly, species in the native range of L. polyphyllus showed no relation to its cover, indicating their ability to thrive even in dense stands of this dominant species.

  5. Burrow characteristics of the co-existing sibling species Mus booduga and Mus terricolor and the genetic basis of adaptation to hypoxic/hypercapnic stress

    Directory of Open Access Journals (Sweden)

    Narayan Gopeshwar

    2009-04-01

    Full Text Available Abstract Background The co-existing, sibling species Mus booduga and Mus terricolor show a difference in site-preference for burrows. The former build them in flat portion of the fields while the latter make burrows in earthen mounds raised for holding water in cultivated fields. In northern India which experiences great variation in climatic condition between summer and winter, M. booduga burrows have an average depth of 41 cm, as against 30 cm in southern India with less climatic fluctuation. M. terricolor burrows are about 20 cm deep everywhere. The three chromosomal species M. terricolor I, II and III have identical burrows, including location of the nest which is situated at the highest position. In contrast, in M. booduga burrows, the nest is at the lowest position. Results The nest chamber of M. booduga is located at greater depth than the nest chamber of M. terricolor. Also, in the burrows of M. booduga the exchange of air takes place only from one side (top surface in contrast to the burrows of M. terricolor where air exchange is through three sides. Hence, M. booduga lives in relatively more hypoxic and hypercapnic conditions than M. terricolor. We observed the fixation of alternative alleles in M. booduga and M. terricolor at Superoxide dismutase-1 (Sod-1, Transferrin (Trf and Hemoglobin beta chain (Hbb loci. All the three are directly or indirectly dependent on oxygen concentration for function. In addition to these, there are differences in burrow patterns and site-preference for burrows suggesting difference in probable adaptive strategy in these co-existing sibling species. Conclusion The burrow structure and depth of nest of the chromosomal species M. terricolor I, II and III are same everywhere probably due to the recency of their evolutionary divergence. Moreover, there is lack of competition for the well-adapted 'microhabitats' since they are non-overlapping in distribution. However, the co-existing sibling species M. booduga

  6. Intraspecific density dependence and a guild of consumers coexisting on one resource.

    Science.gov (United States)

    McPeek, Mark A

    2012-12-01

    The importance of negative intraspecific density dependence to promoting species coexistence in a community is well accepted. However, such mechanisms are typically omitted from more explicit models of community dynamics. Here I analyze a variation of the Rosenzweig-MacArthur consumer-resource model that includes negative intraspecific density dependence for consumers to explore its effect on the coexistence of multiple consumers feeding on a single resource. This analysis demonstrates that a guild of multiple consumers can easily coexist on a single resource if each limits its own abundance to some degree, and stronger intraspecific density dependence permits a wider variety of consumers to coexist. The mechanism permitting multiple consumers to coexist works in a fashion similar to apparent competition or to each consumer having its own specialized predator. These results argue for a more explicit emphasis on how negative intraspecific density dependence is generated and how these mechanisms combine with species interactions to shape overall community structure.

  7. Dispersal and life span spectra in plant communities : a key to safe site dynamics, species coexistence and conservation

    NARCIS (Netherlands)

    Strykstra, RJ; Bekker, RM; Van Andel, J

    Dispersal and life span of individual plant species within five plant communities were assessed to obtain a characterization of these communities in this respect. Such a characterization is important in the context of restoration and maintenance. The most frequent species of five communities were

  8. Differences in the environmental control of leaf senescence of four Quercus species coexisting in a Mediterranean environment

    Directory of Open Access Journals (Sweden)

    Teresa del Río-García

    2015-08-01

    Full Text Available Aims of study: Our aim is to check the effect of different environmental factors on the leaf senescence of four Quercus species with different leaf longevities, to help us better understand the implications of climate change on leaf demography. Area of study: The study was carried out in two sites of the province of Salamanca (central-western Spain, both sites showing differences in their temperatures and soil water availability. Material and Methods: Over four years (2007-2010 we monitored the number of leaves of the different cohorts labelled on five specimens of each species at both sites to elaborate life-tables and calculate mortality rates. Mortality rates were then related to several other variables measured during the same period: air temperature, soil water availability, precipitation, predawn water potentials (Ψpd and leaf N resorption. Main results: In the two deciduous species maximum daily temperatures and the time during which their values remain above a certain threshold (between 11 and 12ºC of maximum daily temperature are the main factors controlling the timing of leaf abscission. In the evergreen species abscission of old leaves showed no relationship with the environmental factors analyzed. By contrast, mortality rates of old leaves were related to seasonal N resorption values, with the maximum mortality of old leaves coinciding in time with the maximum withdrawal of N from shed leaves and also with the emergence of the new leaf cohort. Research highlights: The increase in the duration of the leaves of the two deciduous species, as a result of the delayed senescence by warmer autumnal temperatures, could contribute to reducing the differences in the length of the productive leaf life with respect to the evergreen species. This could improve the competitive capacity of deciduous species as opposed to that of evergreen species, and thus alter their respective distribution patterns.

  9. Examining the Spectral Separability of Prosopis glandulosa from Co-Existent Species Using Field Spectral Measurement and Guided Regularized Random Forest

    Directory of Open Access Journals (Sweden)

    Nyasha Mureriwa

    2016-02-01

    Full Text Available The invasive taxa of Prosopis is rated the world’s top 100 unwanted species, and a lack of spatial data about the invasion dynamics has made the current control and monitoring methods unsuccessful. This study thus tests the use of in situ spectroscopy data with a newly-developed algorithm, guided regularized random forest (GRRF, to spectrally discriminate Prosopis from coexistent acacia species (Acacia karroo, Acacia mellifera and Ziziphus mucronata in the arid environment of South Africa. Results show that GRRF was able to reduce the high dimensionality of the spectroscopy data and select key wavelengths (n = 11 for discriminating amongst the species. These wavelengths are located at 356.3 nm, 468.5 nm, 531.1 nm, 665.2 nm, 1262.3 nm, 1354.1 nm, 1361.7 nm, 1376.9 nm, 1407.1 nm, 1410.9 nm and 1414.6 nm. The use of these selected wavelengths increases the overall classification accuracy from 79.19% and a Kappa value of 0.7201 when using all wavelengths to 88.59% and a Kappa of 0.8524 when the selected wavelengths were used. Based on our relatively high accuracies and ease of use, it is worth considering the GRRF method for reducing the high dimensionality of spectroscopy data. However, this assertion should receive considerable additional testing and comparison before it is accepted as a substitute for reliable high dimensionality reduction.

  10. Habitat requirements, short-term population dynamics and coexistence of native and invasive Impatiens species: a field study

    Czech Academy of Sciences Publication Activity Database

    Čuda, Jan; Skálová, Hana; Janovský, Z.; Pyšek, Petr

    2014-01-01

    Roč. 16, č. 1 (2014), s. 177-190 ISSN 1387-3547 R&D Projects: GA ČR GA206/07/0668 Institutional support: RVO:67985939 Keywords : canopy cover * congeneric species * Ellenberg indicator values Subject RIV: EF - Botanics Impact factor: 2.586, year: 2014

  11. Maintaining distances with the engineer: patterns of coexistence in plant communities beyond the patch-bare dichotomy.

    Science.gov (United States)

    Pescador, David S; Chacón-Labella, Julia; de la Cruz, Marcelino; Escudero, Adrian

    2014-10-01

    Two-phase plant communities with an engineer conforming conspicuous patches and affecting the performance and patterns of coexisting species are the norm under stressful conditions. To unveil the mechanisms governing coexistence in these communities at multiple spatial scales, we have developed a new point-raster approach of spatial pattern analysis, which was applied to a Mediterranean high mountain grassland to show how Festuca curvifolia patches affect the local distribution of coexisting species. We recorded 22 111 individuals of 17 plant perennial species. Most coexisting species were negatively associated with F. curvifolia clumps. Nevertheless, bivariate nearest-neighbor analyses revealed that the majority of coexisting species were confined at relatively short distances from F. curvifolia borders (between 0-2 cm and up to 8 cm in some cases). Our study suggests the existence of a fine-scale effect of F. curvifolia for most species promoting coexistence through a mechanism we call 'facilitation in the halo'. Most coexisting species are displaced to an interphase area between patches, where two opposite forces reach equilibrium: attenuated severe conditions by proximity to the F. curvifolia canopy (nutrient-rich islands) and competitive exclusion mitigated by avoiding direct contact with F. curvifolia. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  12. Identification of Fasciola species based on mitochondrial and nuclear DNA reveals the co-existence of intermediate Fasciola and Fasciola gigantica in Thailand.

    Science.gov (United States)

    Wannasan, Anchalee; Khositharattanakool, Pathamet; Chaiwong, Prasong; Piangjai, Somsak; Uparanukraw, Pichart; Morakote, Nimit

    2014-11-01

    Molecular techniques were used to identify Fasciola species collected from Chiang Mai Thailand. Morphometrically, 65 stained and 45 fresh worms collected from cattle suggested the possible occurrence of both F. gigantica and F. hepatica. Twenty-two worms comprising 15 from cattle and 7 from human patients, were identified subsequently based on three genetic markers: mitochondrial nicotinamide adenine dinucleotide dehydrogenase subunit 1 (nad1), mitochondrial cytochrome c oxidase subunit 1 (cox1) and nuclear ribosomal internal transcribed spacer 2 (ITS2). All of them presented the F. gigantica type in maternally inherited mitochondrial sequences (nad1 and cox1), with six types in each sequence (FgNDI-CM1 to FgNDI-CM6 and FgCOI-CM1 to FgCOI-CM6, respectively). Remarkably, the predominant nad1 type, FgNDI-CM6, was identical to that of aspermic Fasciola sp. formerly reported from Thailand, Japan, Korea, China, Vietnam, and Myanmar. ITS2 sequences were analyzed successfully in 20 worms. Fifteen worms showed the F. gigantica type and five (including one worm from a patient) had mixed ITS2 sequences of both F. gigantica and F. hepatica in the same worms, with additional heterogeneity within both ITS2 types. This study revealed the intermediate form of Fasciola coexisting with F. gigantica for the first time in Thailand.

  13. Coexistence of fish species in a large lowland river: food niche partitioning between small-sized percids, cyprinids and sticklebacks in submersed macrophytes.

    Science.gov (United States)

    Dukowska, Małgorzata; Grzybkowska, Maria

    2014-01-01

    In the spring and summer of each year, large patches of submersed aquatic macrophytes overgrow the bottom of the alluvial Warta River downstream of a large dam reservoir owing to water management practices. Environmental variables, macroinvertebrates (zoobenthos and epiphytic fauna, zooplankton) and fish abundance and biomass were assessed at this biologically productive habitat to learn intraseasonal dynamics of food types, and their occurrence in the gut contents of small-sized roach, dace, perch, ruffe and three-spined stickleback. Gut fullness coefficient, niche breadth and niche overlap indicated how the fishes coexist in the macrophytes. Chironomidae dominated in the diet of the percids. However, ruffe consumed mostly benthic chironomids, while perch epiphytic chironomids and zooplankton. The diet of dace resembled that in fast flowing water although this rheophilic species occurred at unusual density there. The generalist roach displayed the lowest gut fullness coefficient values and widest niche breadth; consequently, intraspecific rather than interspecific competition decided the fate of roach. Three-spined stickleback differed from the other fishes by consuming epiphytic simuliids and fish eggs. The diet overlap between fishes reaching higher gut fullness coefficient values was rather low when the food associated with the submersed aquatic macrophytes was most abundant; this is congruent with the niche overlap hypothesis that maximal tolerable niche overlap can be higher in less intensely competitive conditions.

  14. Stem water storage in five coexisting temperate broad-leaved tree species: significance, temporal dynamics and dependence on tree functional traits.

    Science.gov (United States)

    Köcher, Paul; Horna, Viviana; Leuschner, Christoph

    2013-08-01

    The functional role of internal water storage is increasingly well understood in tropical trees and conifers, while temperate broad-leaved trees have only rarely been studied. We examined the magnitude and dynamics of the use of stem water reserves for transpiration in five coexisting temperate broad-leaved trees with largely different morphology and physiology (genera Fagus, Fraxinus, Tilia, Carpinus and Acer). We expected that differences in water storage patterns would mostly reflect species differences in wood anatomy (ring vs. diffuse-porous) and wood density. Sap flux density was recorded synchronously at five positions along the root-to-branch flow path of mature trees (roots, three stem positions and branches) with high temporal resolution (2 min) and related to stem radius changes recorded with electronic point dendrometers. The daily amount of stored stem water withdrawn for transpiration was estimated by comparing the integrated flow at stem base and stem top. The temporal coincidence of flows at different positions and apparent time lags were examined by cross-correlation analysis. Our results confirm that internal water stores play an important role in the four diffuse-porous species with estimated 5-12 kg day(-1) being withdrawn on average in 25-28 m tall trees representing 10-22% of daily transpiration; in contrast, only 0.5-2.0 kg day(-1) was withdrawn in ring-porous Fraxinus. Wood density had a large influence on storage; sapwood area (diffuse- vs. ring-porous) may be another influential factor but its effect was not significant. Across the five species, the length of the time lag in flow at stem top and stem base was positively related to the size of stem storage. The stem stores were mostly exhausted when the soil matrix potential dropped below -0.1 MPa and daily mean vapor pressure deficit exceeded 3-5 hPa. We conclude that stem storage is an important factor improving the water balance of diffuse-porous temperate broad-leaved trees in moist

  15. Coexistence of competing stage-structured populations.

    KAUST Repository

    Fujiwara, Masami; Pfeiffer, Georgia; Boggess, May; Day, Sarah; Walton, Jay

    2011-01-01

    -use overlap. The former ratio, which we define as fitness, can be equalized by adjusting organisms' life history strategies, thereby promoting coexistence. We conclude that in addition to niche differentiation among populations, the life history strategies

  16. Soil phosphorus heterogeneity promotes tree species diversity and phylogenetic clustering in a tropical seasonal rainforest.

    Science.gov (United States)

    Xu, Wumei; Ci, Xiuqin; Song, Caiyun; He, Tianhua; Zhang, Wenfu; Li, Qiaoming; Li, Jie

    2016-12-01

    The niche theory predicts that environmental heterogeneity and species diversity are positively correlated in tropical forests, whereas the neutral theory suggests that stochastic processes are more important in determining species diversity. This study sought to investigate the effects of soil nutrient (nitrogen and phosphorus) heterogeneity on tree species diversity in the Xishuangbanna tropical seasonal rainforest in southwestern China. Thirty-nine plots of 400 m 2 (20 × 20 m) were randomly located in the Xishuangbanna tropical seasonal rainforest. Within each plot, soil nutrient (nitrogen and phosphorus) availability and heterogeneity, tree species diversity, and community phylogenetic structure were measured. Soil phosphorus heterogeneity and tree species diversity in each plot were positively correlated, while phosphorus availability and tree species diversity were not. The trees in plots with low soil phosphorus heterogeneity were phylogenetically overdispersed, while the phylogenetic structure of trees within the plots became clustered as heterogeneity increased. Neither nitrogen availability nor its heterogeneity was correlated to tree species diversity or the phylogenetic structure of trees within the plots. The interspecific competition in the forest plots with low soil phosphorus heterogeneity could lead to an overdispersed community. However, as heterogeneity increase, more closely related species may be able to coexist together and lead to a clustered community. Our results indicate that soil phosphorus heterogeneity significantly affects tree diversity in the Xishuangbanna tropical seasonal rainforest, suggesting that deterministic processes are dominant in this tropical forest assembly.

  17. Feeding patterns of migratory and non-migratory fourth instar larvae of two coexisting Chaoborus species in an acidic and metal contaminated lake: Importance of prey ingestion rate in predicting metal bioaccumulation

    Science.gov (United States)

    Croteau, M.-N.; Hare, L.; Marcoux, P.

    2003-01-01

    We studied diel variations in the feeding habits and migratory behaviors of two coexisting Chaoborus species in an acidic and metal contaminated lake (Lake Turcotte, QC, Canada). We found that although the zooplankton community was dominated by rotifers, both Chaoborus species fed mostly on chironomids and crustaceans despite the relatively low abundance of these prey types in the lake plankton. Chaoborus americanus larvae fed on those of Chaoborus punctipennis, but not vice versa. The non-migratory species (C. americanus) fed throughout the day and night whereas the migratory species (C. punctipennis) fed only at night while in the water column. The larger-bodied C. americanus consumed more prey and had a more diverse diet than did the smaller-bodied C. punctipennis. Differences in feeding habits between the Chaoborus species inhabiting Lake Turcotte (prey biomass, prey types) likely explain in part their ability to coexist. Attempts to predict Cd in the Chaoborus species using our measurements of Cd in their prey and their prey ingestion rates met with mixed success; although we correctly predicted higher Cd concentrations for C. americanus larvae than for C. punctipennis larvae, we under-predicted absolute Cd concentrations. We suggest that studies such as ours that are based on analyses of gut contents of larvae collected at intervals of 4h or longer likely underestimate prey ingestion rates.

  18. Characterization and identification of microRNA core promoters in four model species.

    Directory of Open Access Journals (Sweden)

    Xuefeng Zhou

    2007-03-01

    Full Text Available MicroRNAs are short, noncoding RNAs that play important roles in post-transcriptional gene regulation. Although many functions of microRNAs in plants and animals have been revealed in recent years, the transcriptional mechanism of microRNA genes is not well-understood. To elucidate the transcriptional regulation of microRNA genes, we study and characterize, in a genome scale, the promoters of intergenic microRNA genes in Caenorhabditis elegans, Homo sapiens, Arabidopsis thaliana, and Oryza sativa. We show that most known microRNA genes in these four species have the same type of promoters as protein-coding genes have. To further characterize the promoters of microRNA genes, we developed a novel promoter prediction method, called common query voting (CoVote, which is more effective than available promoter prediction methods. Using this new method, we identify putative core promoters of most known microRNA genes in the four model species. Moreover, we characterize the promoters of microRNA genes in these four species. We discover many significant, characteristic sequence motifs in these core promoters, several of which match or resemble the known cis-acting elements for transcription initiation. Among these motifs, some are conserved across different species while some are specific to microRNA genes of individual species.

  19. Soil communities promote temporal stability and species asynchrony in experimental grassland communities

    NARCIS (Netherlands)

    Pellkofer, Sarah; Van Der Heijden, Marcel G A; Schmid, Bernhard; Wagg, Cameron

    2016-01-01

    Background Over the past two decades many studies have demonstrated that plant species diversity promotes primary productivity and stability in grassland ecosystems. Additionally, soil community characteristics have also been shown to influence the productivity and composition of plant communities,

  20. Cross-species mapping of bidirectional promoters enables prediction of unannotated 5' UTRs and identification of species-specific transcripts

    Directory of Open Access Journals (Sweden)

    Lewin Harris A

    2009-04-01

    Full Text Available Abstract Background Bidirectional promoters are shared regulatory regions that influence the expression of two oppositely oriented genes. This type of regulatory architecture is found more frequently than expected by chance in the human genome, yet many specifics underlying the regulatory design are unknown. Given that the function of most orthologous genes is similar across species, we hypothesized that the architecture and regulation of bidirectional promoters might also be similar across species, representing a core regulatory structure and enabling annotation of these regions in additional mammalian genomes. Results By mapping the intergenic distances of genes in human, chimpanzee, bovine, murine, and rat, we show an enrichment for pairs of genes equal to or less than 1,000 bp between their adjacent 5' ends ("head-to-head" compared to pairs of genes that fall in the same orientation ("head-to-tail" or whose 3' ends are side-by-side ("tail-to-tail". A representative set of 1,369 human bidirectional promoters was mapped to orthologous sequences in other mammals. We confirmed predictions for 5' UTRs in nine of ten manual picks in bovine based on comparison to the orthologous human promoter set and in six of seven predictions in human based on comparison to the bovine dataset. The two predictions that did not have orthology as bidirectional promoters in the other species resulted from unique events that initiated transcription in the opposite direction in only those species. We found evidence supporting the independent emergence of bidirectional promoters from the family of five RecQ helicase genes, which gained their bidirectional promoters and partner genes independently rather than through a duplication process. Furthermore, by expanding our comparisons from pairwise to multispecies analyses we developed a map representing a core set of bidirectional promoters in mammals. Conclusion We show that the orthologous positions of bidirectional

  1. Ecophysiological adaptations of coexisting Sphagnum mosses

    OpenAIRE

    HÁJEK, Tomáš

    2008-01-01

    I studied ecological and physiological adaptations of peat misses (Sphagnum species) coexisting along the environmental gradients in mires. Production, decomposition, water relations, desiccation tolerance and nutrient economy of Sphagnum species were evaluates along the hummock-hollow gradient of water table, while the light adaptations were assessed in an open and forested mire

  2. Richness of lichen species, especially of threatened ones, is promoted by management methods furthering stand continuity.

    Directory of Open Access Journals (Sweden)

    Steffen Boch

    Full Text Available Lichens are a key component of forest biodiversity. However, a comprehensive study analyzing lichen species richness in relation to several management types, extending over different regions and forest stages and including information on site conditions is missing for temperate European forests. In three German regions (Schwäbische Alb, Hainich-Dün, Schorfheide-Chorin, the so-called Biodiversity Exploratories, we studied lichen species richness in 631 forest plots of 400 m(2 comprising different management types (unmanaged, selection cutting, deciduous and coniferous age-class forests resulting from clear cutting or shelterwood logging, various stand ages, and site conditions, typical for large parts of temperate Europe. We analyzed how lichen species richness responds to management and habitat variables (standing biomass, cover of deadwood, cover of rocks. We found strong regional differences with highest lichen species richness in the Schwäbische Alb, probably driven by regional differences in former air pollution, and in precipitation and habitat variables. Overall, unmanaged forests harbored 22% more threatened lichen species than managed age-class forests. In general, total, corticolous, and threatened lichen species richness did not differ among management types of deciduous forests. However, in the Schwäbische-Alb region, deciduous forests had 61% more lichen species than coniferous forests and they had 279% more threatened and 76% more corticolous lichen species. Old deciduous age classes were richer in corticolous lichen species than young ones, while old coniferous age-classes were poorer than young ones. Overall, our findings highlight the importance of stand continuity for conservation. To increase total and threatened lichen species richness we suggest (1 conserving unmanaged forests, (2 promoting silvicultural methods assuring stand continuity, (3 conserving old trees in managed forests, (4 promoting stands of native deciduous

  3. Richness of Lichen Species, Especially of Threatened Ones, Is Promoted by Management Methods Furthering Stand Continuity

    Science.gov (United States)

    Boch, Steffen; Prati, Daniel; Hessenmöller, Dominik; Schulze, Ernst-Detlef; Fischer, Markus

    2013-01-01

    Lichens are a key component of forest biodiversity. However, a comprehensive study analyzing lichen species richness in relation to several management types, extending over different regions and forest stages and including information on site conditions is missing for temperate European forests. In three German regions (Schwäbische Alb, Hainich-Dün, Schorfheide-Chorin), the so-called Biodiversity Exploratories, we studied lichen species richness in 631 forest plots of 400 m2 comprising different management types (unmanaged, selection cutting, deciduous and coniferous age-class forests resulting from clear cutting or shelterwood logging), various stand ages, and site conditions, typical for large parts of temperate Europe. We analyzed how lichen species richness responds to management and habitat variables (standing biomass, cover of deadwood, cover of rocks). We found strong regional differences with highest lichen species richness in the Schwäbische Alb, probably driven by regional differences in former air pollution, and in precipitation and habitat variables. Overall, unmanaged forests harbored 22% more threatened lichen species than managed age-class forests. In general, total, corticolous, and threatened lichen species richness did not differ among management types of deciduous forests. However, in the Schwäbische-Alb region, deciduous forests had 61% more lichen species than coniferous forests and they had 279% more threatened and 76% more corticolous lichen species. Old deciduous age classes were richer in corticolous lichen species than young ones, while old coniferous age-classes were poorer than young ones. Overall, our findings highlight the importance of stand continuity for conservation. To increase total and threatened lichen species richness we suggest (1) conserving unmanaged forests, (2) promoting silvicultural methods assuring stand continuity, (3) conserving old trees in managed forests, (4) promoting stands of native deciduous tree species

  4. Species selection in secondary wood products: implications for product design and promotion

    Science.gov (United States)

    Matthew S. Bumgardner; Scott A. Bowe; Scott A. Bowe

    2002-01-01

    This study investigated the perceptions that people have of several commercially important wood species and determined if word-based and specimen-based evaluations differed. Such knowledge can help secondary wood manufacturers better understand their products and develop more effective design concepts and promotional messages. A sample of more than 250 undergraduate...

  5. Coexistence of surface and cave amphipods in an ecotone environment

    NARCIS (Netherlands)

    Luštrik, R.; Turjak, M.; Kralj-Fišer, S.; Fišer, C.

    2011-01-01

    Interspecific interactions between surface and subterranean species may be a key determinant for species distributions. Until now, the existence of competition (including predation) between these groups has not been tested. To assess the coexistence and potential role of interspecific interactions

  6. Distribution and co-existence of the Macropis species and their cleptoparasite Epeoloides coecutiens (Fabr.) in NW Europe Hymenoptera: Apoidea, Melittidae and Apidae)

    DEFF Research Database (Denmark)

    Pekkarinen, Antti; Berg, Øistein; Calabuig, Isabel

    2003-01-01

    The Macropis species collect pollen and fatty oil secreted by flowers of loosestrifes (Lysimachia, Primulaceae) and are the only known oil-collecting bees in the Holarctic. In NW Europe, L. vulgaris is the main or (in large areas) sole pollen and oil source for M. europaea Warncke (labiata auct.......) and M. fulvipes (Fabr.). The species are largely sympatric in southern Finland and the Baltic countries, while in Scandinavia and most of Denmark only M. europaea has been recorded. The ranges of the Macropis species are restricted to the areas of common occurrence of L. vulgaris. Presumably, Epeoloides...

  7. Chlamydia infection across host species boundaries promotes distinct sets of transcribed anti-apoptotic factors.

    Directory of Open Access Journals (Sweden)

    Joshua eMessinger

    2015-12-01

    Full Text Available Chlamydiae, obligate intracellular bacteria, cause significant human and veterinary associated diseases. Having emerged an estimated 700-million years ago, these bacteria have twice adapted to humans as a host species, causing sexually transmitted infection (C. trachomatis and respiratory associated disease (C. pneumoniae. The principle mechanism of host cell defense against these intracellular bacteria is the induction of cell death via apoptosis. However, in the arms race of co-evolution, Chlamydiae have developed mechanisms to promote cell viability and inhibit cell death. Herein we examine the impact of Chlamydiae infection across multiple host species on transcription of anti-apoptotic genes. We found mostly distinct patterns of gene expression (Mcl1 and cIAPs elicited by each pathogen-host pair indicating Chlamydiae infection across host species boundaries does not induce a universally shared host response. Understanding species specific host-pathogen interactions is paramount to deciphering how potential pathogens become emerging diseases.

  8. Contrasting impacts of continuous moderate drought and episodic severe droughts on the aboveground-biomass increment and litterfall of three coexisting Mediterranean woody species.

    Science.gov (United States)

    Liu, Daijun; Ogaya, Romà; Barbeta, Adrià; Yang, Xiaohong; Peñuelas, Josep

    2015-11-01

    Climate change is predicted to increase the aridity in the Mediterranean Basin and severely affect forest productivity and composition. The responses of forests to different timescales of drought, however, are still poorly understood because extreme and persistent moderate droughts can produce nonlinear responses in plants. We conducted a rainfall-manipulation experiment in a Mediterranean forest dominated by Quercus ilex, Phillyrea latifolia, and Arbutus unedo in the Prades Mountains in southern Catalonia from 1999 to 2014. The experimental drought significantly decreased forest aboveground-biomass increment (ABI), tended to increase the litterfall, and decreased aboveground net primary production throughout the 15 years of the study. The responses to the experimental drought were highly species-specific. A. unedo suffered a significant reduction in ABI, Q. ilex experienced a decrease during the early experiment (1999-2003) and in the extreme droughts of 2005-2006 and 2011-2012, and P. latifolia was unaffected by the treatment. The drought treatment significantly increased branch litterfall, especially in the extremely dry year of 2011, and also increased overall leaf litterfall. The drought treatment reduced the fruit production of Q. ilex, which affected seedling recruitment. The ABIs of all species were highly correlated with SPEI in early spring, whereas the branch litterfalls were better correlated with summer SPEIs and the leaf and fruit litterfalls were better correlated with autumn SPEIs. These species-specific responses indicated that the dominant species (Q. ilex) could be partially replaced by the drought-resistant species (P. latifolia). However, the results of this long-term study also suggest that the effect of drought treatment has been dampened over time, probably due to a combination of demographic compensation, morphological and physiological acclimation, and epigenetic changes. However, the structure of community (e.g., species composition

  9. Do species differ in their ability to coexist with the dominant alien Lupinus polyphyllus? A comparison between two distinct invaded ranges and a native range

    Czech Academy of Sciences Publication Activity Database

    Hejda, Martin

    2013-01-01

    Roč. 17, jun 2013 (2013), s. 39-55 ISSN 1619-0033 R&D Projects: GA ČR(CZ) GAP505/11/1112; GA ČR GA206/07/0668 Institutional support: RVO:67985939 Keywords : lupinus polyphyllus * invasive alien species * native range Subject RIV: EF - Botanics

  10. Coexistence between neighbours

    DEFF Research Database (Denmark)

    Shenge, K.C.; Mabagala, R.B.; Mortensen, C A Nieves Paulino

    2008-01-01

    Experiments were conducted under laboratory and screenhouse conditions to study the coexistence between Pseudomonas syringae pv. tomato and Xanthomonas campestris pv. vesicatoria, incitants of bacterial speck and bacterial spot diseases of tomato. Results of in vitro studies showed that when mixe...

  11. Climate change has indirect effects on resource use and overlap among coexisting bird species with negative consequences for their reproductive success.

    Science.gov (United States)

    Auer, Sonya K; Martin, Thomas E

    2013-02-01

    Climate change can modify ecological interactions, but whether it can have cascading effects throughout ecological networks of multiple interacting species remains poorly studied. Climate-driven alterations in the intensity of plant-herbivore interactions may have particularly profound effects on the larger community because plants provide habitat for a wide diversity of organisms. Here we show that changes in vegetation over the last 21 years, due to climate effects on plant-herbivore interactions, have consequences for songbird nest site overlap and breeding success. Browsing-induced reductions in the availability of preferred nesting sites for two of three ground nesting songbirds led to increasing overlap in nest site characteristics among all three bird species with increasingly negative consequences for reproductive success over the long term. These results demonstrate that changes in the vegetation community from effects of climate change on plant-herbivore interactions can cause subtle shifts in ecological interactions that have critical demographic ramifications for other species in the larger community. © 2012 Blackwell Publishing Ltd.

  12. Climate change has indirect effects on resource use and overlap among coexisting bird species with negative consequences for their reproductive success

    Science.gov (United States)

    Martin, Thomas E.; Auer, Sonya K.

    2013-01-01

    Climate change can modify ecological interactions, but whether it can have cascading effects throughout ecological networks of multiple interacting species remains poorly studied. Climate-driven alterations in the intensity of plant–herbivore interactions may have particularly profound effects on the larger community because plants provide habitat for a wide diversity of organisms. Here we show that changes in vegetation over the last 21 years, due to climate effects on plant–herbivore interactions, have consequences for songbird nest site overlap and breeding success. Browsing-induced reductions in the availability of preferred nesting sites for two of three ground nesting songbirds led to increasing overlap in nest site characteristics among all three bird species with increasingly negative consequences for reproductive success over the long term. These results demonstrate that changes in the vegetation community from effects of climate change on plant–herbivore interactions can cause subtle shifts in ecological interactions that have critical demographic ramifications for other species in the larger community.

  13. Coexistence of competing stage-structured populations.

    KAUST Repository

    Fujiwara, Masami

    2011-10-05

    This paper analyzes the stability of a coexistence equilibrium point of a model for competition between two stage-structured populations. In this model, for each population, competition for resources may affect any one of the following population parameters: reproduction, juvenile survival, maturation rate, or adult survival. The results show that the competitive strength of a population is affected by (1) the ratio of the population parameter influenced by competition under no resource limitation (maximum compensatory capacity) over the same parameter under a resource limitation due to competition (equilibrium rate) and (2) the ratio of interspecific competition over intraspecific competition; this ratio was previously shown to depend on resource-use overlap. The former ratio, which we define as fitness, can be equalized by adjusting organisms\\' life history strategies, thereby promoting coexistence. We conclude that in addition to niche differentiation among populations, the life history strategies of organisms play an important role in coexistence.

  14. Nickel detoxification and plant growth promotion by multi metal resistant plant growth promoting Rhizobium species RL9.

    Science.gov (United States)

    Wani, Parvaze Ahmad; Khan, Mohammad Saghir

    2013-07-01

    Pollution of the biosphere by heavy metals is a global threat that has accelerated dramatically since the beginning of industrial revolution. The aim of the study is to check the resistance of RL9 towards the metals and to observe the effect of Rhizobium species on growth, pigment content, protein and nickel uptake by lentil in the presence and absence of nickel. The multi metal tolerant and plant growth promoting Rhizobium strain RL9 was isolated from the nodules of lentil. The strain not only tolerated nickel but was also tolerant o cadmium, chromium, nickel, lead, zinc and copper. The strain tolerated nickel 500 μg/mL, cadmium 300 μg/mL, chromium 400 μg/mL, lead 1,400 μg/mL, zinc 1,000 μg/mL and copper 300 μg/mL, produced good amount of indole acetic acid and was also positive for siderophore, hydrogen cyanide and ammonia. The strain RL9 was further assessed with increasing concentrations of nickel when lentil was used as a test crop. The strain RL9 significantly increased growth, nodulation, chlorophyll, leghaemoglobin, nitrogen content, seed protein and seed yield compared to plants grown in the absence of bioinoculant but amended with nickel The strain RL9 decreased uptake of nickel in lentil compared to plants grown in the absence of bio-inoculant. Due to these intrinsic abilities strain RL9 could be utilized for growth promotion as well as for the remediation of nickel in nickel contaminated soil.

  15. Seasonal and inter-annual variation in the chlorophyll content of three co-existing Sphagnum species exceeds the effect of solar UV reduction in a subarctic peatland.

    Science.gov (United States)

    Hyyryläinen, Anna; Rautio, Pasi; Turunen, Minna; Huttunen, Satu

    2015-01-01

    We measured chlorophyll (chl) concentration and chl a/b ratio in Sphagnum balticum, S. jensenii, and S. lindbergii, sampled after 7 and 8 years of ultraviolet-B (UVB) and temperature manipulation in an open field experiment in Finnish Lapland (68°N). We used plastic filters with different transmittance of UVB radiation to manipulate the environmental conditions. The plants were exposed to (1) attenuated UVB and increased temperature, (2) ambient UVB and increased temperature and (3) ambient conditions. Chlorophyll was extracted from the capitula of the mosses and the content and a/b ratio were measured spectrophotometrically. Seasonal variation of chlorophyll concentration in the mosses was species specific. Temperature increase to 0.5-1 °C and/or attenuation of solar UVB radiation to ca. one fifth of the ambient (on average 12 vs. 59 uW/cm(2)) had little effect on the chlorophyll concentration or its seasonal variation. In the dominant S. lindbergii, UVB attenuation under increased temperature led to a transient decrease in chlorophyll concentration. Altogether, species-specific patterns of seasonal chlorophyll variation in the studied Sphagna were more pronounced than temperature and UVB treatment effects.

  16. Conditions Promoting Mycorrhizal Parasitism Are of Minor Importance for Competitive Interactions in Two Differentially Mycotrophic Species

    Science.gov (United States)

    Friede, Martina; Unger, Stephan; Hellmann, Christine; Beyschlag, Wolfram

    2016-01-01

    Interactions of plants with arbuscular mycorrhizal fungi (AMF) may range along a broad continuum from strong mutualism to parasitism, with mycorrhizal benefits received by the plant being determined by climatic and edaphic conditions affecting the balance between carbon costs vs. nutritional benefits. Thus, environmental conditions promoting either parasitism or mutualism can influence the mycorrhizal growth dependency (MGD) of a plant and in consequence may play an important role in plant-plant interactions. In a multifactorial field experiment we aimed at disentangling the effects of environmental and edaphic conditions, namely the availability of light, phosphorus and nitrogen, and the implications for competitive interactions between Hieracium pilosella and Corynephorus canescens for the outcome of the AMF symbiosis. Both species were planted in single, intraspecific and interspecific combinations using a target-neighbor approach with six treatments distributed along a gradient simulating conditions for the interaction between plants and AMF ranking from mutualistic to parasitic. Across all treatments we found mycorrhizal association of H. pilosella being consistently mutualistic, while pronounced parasitism was observed in C. canescens, indicating that environmental and edaphic conditions did not markedly affect the cost:benefit ratio of the mycorrhizal symbiosis in both species. Competitive interactions between both species were strongly affected by AMF, with the impact of AMF on competition being modulated by colonization. Biomass in both species was lowest when grown in interspecific competition, with colonization being increased in the less mycotrophic C. canescens, while decreased in the obligate mycotrophic H. pilosella. Although parasitism-promoting conditions negatively affected MGD in C. canescens, these effects were small as compared to growth decreases related to increased colonization levels in this species. Thus, the lack of plant control over

  17. Conditions Promoting Mycorrhizal Parasitism are of Minor Importance for Competitive Interactions in Two Differentially Mycotrophic Species

    Directory of Open Access Journals (Sweden)

    Martina Friede

    2016-09-01

    Full Text Available Interactions of plants with arbuscular mycorrhizal fungi (AMF may range along a broad continuum from strong mutualism to parasitism, with mycorrhizal benefits received by the plant being determined by climatic and edaphic conditions affecting the balance between carbon costs vs. nutritional benefits. Thus, environmental conditions promoting either parasitism or mutualism can influence the mycorrhizal growth dependency (MGD of a plant and in consequence may play an important role in plant-plant interactions.In a multifactorial field experiment we aimed at disentangling the effects of environmental and edaphic conditions, namely the availability of light, phosphorus and nitrogen, and the implications for competitive interactions between Hieracium pilosella and Corynephorus canescens for the outcome of the AMF symbiosis. Both species were planted in single, intraspecific and interspecific combinations using a target-neighbor approach with six treatments distributed along a gradient simulating conditions for the interaction between plants and AMF ranking from mutualistic to parasitic.Across all treatments we found mycorrhizal association of H. pilosella being consistently mutualistic, while pronounced parasitism was observed in C. canescens, indicating that environmental and edaphic conditions did not markedly affect the cost:benefit ratio of the mycorrhizal symbiosis in both species. Competitive interactions between both species were strongly affected by AMF, with the impact of AMF on competition being modulated by colonization. Biomass in both species was lowest when grown in interspecific competition, with colonization being increased in the less mycotrophic C. canescens, while decreased in the obligate mycotrophic H. pilosella. Although parasitism-promoting conditions negatively affected MGD in C. canescens, these effects were small as compared to growth decreases related to increased colonization levels in this species. Thus, the lack of plant

  18. Introduced species as evolutionary traps

    Science.gov (United States)

    Schlaepfer, Martin A.; Sherman, P.W.; Blossey, B.; Runge, M.C.

    2005-01-01

    Invasive species can alter environments in such a way that normal behavioural decision-making rules of native species are no longer adaptive. The evolutionary trap concept provides a useful framework for predicting and managing the impact of harmful invasive species. We discuss how native species can respond to changes in their selective regime via evolution or learning. We also propose novel management strategies to promote the long-term co-existence of native and introduced species in cases where the eradication of the latter is either economically or biologically unrealistic.

  19. Coexistence of three specialist aphids on common milkweed, Asclepias syriaca.

    Science.gov (United States)

    Smith, R A; Mooney, K A; Agrawal, A A

    2008-08-01

    Coexistence of host-specific herbivores on plants is believed to be governed by interspecific interactions, but few empirical studies have systematically unraveled these dynamics. We investigated the role of several factors in promoting coexistence among the aphids Aphis nerii, Aphis asclepiadis, and Myzocallis asclepiadis that all specialize on common milkweed (Asclepias syriaca). Competitive exclusion is thought to occur when interspecific competition is stronger than intraspecific competition. Consequently, we investigated whether predators, mutualists, or resource quality affected the strength of intra- vs. interspecific competition among aphids in factorial manipulations of competition with exposure to predation, ants, and variable plant genotypes in three separate experiments. In the predation x competition experiment, predators reduced aphid per capita growth by 66%, but the strength of intra- and interspecific competition did not depend on predators. In the ants x competition experiment, ants reduced per capita growth of A. nerii and M. asclepiadis (neither of which were mutualists with ants) by approximately one-half. In so doing, ants ameliorated the negative effects of these competitors on ant-tended A. asclepiadis by two-thirds, representing a novel benefit of ant-aphid mutualism. Nevertheless, ants alone did not explain the persistence of competitively inferior A. asclepiadis as, even in the presence of ants, interspecific competition remained stronger than intraspecific competition. In the plant genotype x competition experiment, both A. asclepiadis and M. asclepiadis were competitively inferior to A. nerii, with the strength of interspecific competition exceeding that of intraspecific competition by 83% and 23%, respectively. Yet these effects differed among milkweed genotypes, and there were one or more plant genotypes for each aphid species where coexistence was predicted. A synthesis of our results shows that predators play little or no role in

  20. Body size mediated coexistence in swans.

    Science.gov (United States)

    Engelhardt, Katharina A M; Ritchie, Mark E; Powell, James A

    2014-01-01

    Differences in body sizes may create a trade-off between foraging efficiency (foraging gains/costs) and access to resources. Such a trade-off provides a potential mechanism for ecologically similar species to coexist on one resource. We explored this hypothesis for tundra (Cygnus columbianus) and trumpeter swans (Cygnus buccinator), a federally protected species, feeding solely on sago pondweed (Stuckenia pectinata) tubers during fall staging and wintering in northern Utah. Foraging efficiency was higher for tundra swans because this species experienced lower foraging and metabolic costs relative to foraging gains; however, trumpeter swans (a) had longer necks and therefore had access to exclusive resources buried deep in wetland sediments and (b) were more aggressive and could therefore displace tundra swans from lucrative foraging locations. We conclude that body size differentiation is an important feature of coexistence among ecologically similar species feeding on one resource. In situations where resources are limiting and competition for resources is strong, conservation managers will need to consider the trade-off between foraging efficiency and access to resources to ensure ecologically similar species can coexist on a shared resource.

  1. Body Size Mediated Coexistence in Swans

    Directory of Open Access Journals (Sweden)

    Katharina A. M. Engelhardt

    2014-01-01

    Full Text Available Differences in body sizes may create a trade-off between foraging efficiency (foraging gains/costs and access to resources. Such a trade-off provides a potential mechanism for ecologically similar species to coexist on one resource. We explored this hypothesis for tundra (Cygnus columbianus and trumpeter swans (Cygnus buccinator, a federally protected species, feeding solely on sago pondweed (Stuckenia pectinata tubers during fall staging and wintering in northern Utah. Foraging efficiency was higher for tundra swans because this species experienced lower foraging and metabolic costs relative to foraging gains; however, trumpeter swans (a had longer necks and therefore had access to exclusive resources buried deep in wetland sediments and (b were more aggressive and could therefore displace tundra swans from lucrative foraging locations. We conclude that body size differentiation is an important feature of coexistence among ecologically similar species feeding on one resource. In situations where resources are limiting and competition for resources is strong, conservation managers will need to consider the trade-off between foraging efficiency and access to resources to ensure ecologically similar species can coexist on a shared resource.

  2. Plant growth-promoting Burkholderia species isolated from annual ryegrass in Portuguese soils.

    Science.gov (United States)

    Castanheira, N; Dourado, A C; Kruz, S; Alves, P I L; Delgado-Rodríguez, A I; Pais, I; Semedo, J; Scotti-Campos, P; Sánchez, C; Borges, N; Carvalho, G; Barreto Crespo, M T; Fareleira, P

    2016-03-01

    To search for culturable Burkholderia species associated with annual ryegrass in soils from natural pastures in Portugal, with plant growth-promoting effects. Annual ryegrass seedlings were used to trap Burkholderia from two different soils in laboratory conditions. A combined approach using genomic fingerprinting and sequencing of 16S rRNA and recA genes resulted in the identification of Burkholderia strains belonging to the species Burkholderia graminis, Burkholderia fungorum and the Burkholderia cepacia complex. Most strains were able to solubilize mineral phosphate and to synthesize indole acetic acid; some of them could produce siderophores and antagonize the phytopathogenic oomycete, Phytophthora cinnamomi. A strain (G2Bd5) of B. graminis was selected for gnotobiotic plant inoculation experiments. The main effects were the stimulation of root growth and enhancement of leaf lipid synthesis and turnover. Fluorescence in situ hybridization and confocal laser microscopy evidenced that strain G2Bd5 is a rhizospheric and endophytic colonizer of annual ryegrass. This work revealed that annual ryegrass can naturally associate with members of the genus Burkholderia. A novel plant growth promoting strain of B. graminis was obtained. The novel strain belongs to the plant-associated Burkholderia cluster and is a promising candidate for exploitation as plant inoculant in field conditions. © 2015 The Society for Applied Microbiology.

  3. Coexistence via coevolution driven by reduced allelochemical effects and increased tolerance to competition between invasive and native plants.

    Science.gov (United States)

    Huang, Fangfang; Lankau, Richard; Peng, Shaolin

    2018-04-01

    Coevolution can promote long-term coexistence of two competing species if selection acts to reduce the fitness inequality between competitors and/or strengthen negative frequency dependence within each population. However, clear coevolution between plant competitors has been rarely documented. Plant invasions offer opportunities to capture the process of coevolution. Here we investigated how the developing relationship between an invasive forb, Alliaria petiolata, and a native competitor, Pilea pumila, may affect their long-term coexistence, by testing the competitive effects of populations of varying lengths of co-occurrence on each other across a chronosequence of invasion history. Alliaria petiolata and P. pumila tended to develop greater tolerance to competition over invasion history. Their coexistence was promoted more by increases in stabilizing relative to equalizing processes. These changes likely stem in part from reductions in allelopathic traits in the invader and evolution of tolerance in the native. These results suggested that some native species can evolve tolerance against the competitive effects of strong invaders, which likely promoted their persistence in invaded communities. However, the potential for coevolutionary rescue of competing populations is likely to vary across native species, and evolutionary processes should not be expected to compensate for the ecological consequences of exotic invasions. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  4. Promotion of hydrogen entry into iron from NaOH solution by iron-oxygen species

    International Nuclear Information System (INIS)

    Flis-Kabulska, I.; Flis, J.; Zakroczymski, T.

    2007-01-01

    This study was carried out to explain reasons of the enhanced hydrogen entry into iron at low polarisations. Hydrogen permeation rate (HPR) through a 35-μm thick iron membrane was studied with the electrochemical technique in 0.1 M NaOH at 25 o C. A rotating split-ring disk electrode was used to detect soluble Fe(II) species. Enhanced hydrogen entry (HPR peaks) was observed at low cathodic and low anodic polarisations during voltammetric cycling, and also during galvanostatic anodic polarisation applied after cathodic charging. HPR peaks occurred at potentials from about -1.2 to -0.9 V (NHE) which were more cathodic than the potentials of thermodynamic stability of Fe(OH) 2 or Fe 3 O 4 , and of the formation of soluble Fe(II) species. It has been suggested that the enhanced hydrogen entry is associated with the presence of FeOH ad . In this species oxygen is bound with hydrogen (oxo-hydride), hence it can be supposed that the mechanism of its promoting effect can be similar to that of hydrides of other elements of the VIb group

  5. Crosstalk between sugarcane and a plant-growth promoting Burkholderia species

    Science.gov (United States)

    Paungfoo-Lonhienne, Chanyarat; Lonhienne, Thierry G. A.; Yeoh, Yun Kit; Donose, Bogdan C.; Webb, Richard I.; Parsons, Jeremy; Liao, Webber; Sagulenko, Evgeny; Lakshmanan, Prakash; Hugenholtz, Philip; Schmidt, Susanne; Ragan, Mark A.

    2016-01-01

    Bacterial species in the plant-beneficial-environmental clade of Burkholderia represent a substantial component of rhizosphere microbes in many plant species. To better understand the molecular mechanisms of the interaction, we combined functional studies with high-resolution dual transcriptome analysis of sugarcane and root-associated diazotrophic Burkholderia strain Q208. We show that Burkholderia Q208 forms a biofilm at the root surface and suppresses the virulence factors that typically trigger immune response in plants. Up-regulation of bd-type cytochromes in Burkholderia Q208 suggests an increased energy production and creates the microaerobic conditions suitable for BNF. In this environment, a series of metabolic pathways are activated in Burkholderia Q208 implicated in oxalotrophy, microaerobic respiration, and formation of PHB granules, enabling energy production under microaerobic conditions. In the plant, genes involved in hypoxia survival are up-regulated and through increased ethylene production, larger aerenchyma is produced in roots which in turn facilitates diffusion of oxygen within the cortex. The detected changes in gene expression, physiology and morphology in the partnership are evidence of a sophisticated interplay between sugarcane and a plant-growth promoting Burkholderia species that advance our understanding of the mutually beneficial processes occurring in the rhizosphere. PMID:27869215

  6. Co-existence in multispecies biofilm communities

    DEFF Research Database (Denmark)

    Røder, Henriette Lyng

    of these emergent properties which are relevant to as diverse areas as clinical settings and natural systems. In this thesis, I have attempted to contribute to our knowledge on the multispecies interactions with a special focus on biofilm communities. I was especially interested in how co-existing species affect...... each other and in understanding the key mechanisms and interactions involved. In the introduction of this thesis the most important concepts of multi-species interactions and biofilm development are explained. After this the topic changes to the various ways of examining community interactions...... and production. The analysis was further extended in manuscript 3, in which the effect of social interac-tions on biofilm formation in multispecies co-cultures isolated from a diverse range of environments was examined. The question raised was whether the interspecific interactions of co-existing bacteria...

  7. Coexistence of structured populations with size-based prey selection

    DEFF Research Database (Denmark)

    Hartvig, Martin; Andersen, Ken Haste

    2013-01-01

    Abstract Species with a large adult-offspring size ratio and a preferred predator–prey mass ratio undergo ontogenetic trophic niche shift(s) throughout life. Trophic interactions between such species vary throughout life, resulting in different species-level interaction motifs depending on the ma......Abstract Species with a large adult-offspring size ratio and a preferred predator–prey mass ratio undergo ontogenetic trophic niche shift(s) throughout life. Trophic interactions between such species vary throughout life, resulting in different species-level interaction motifs depending...... on the maximum adult sizes and population size distributions. We explore the assembly and potential for coexistence of small communities where all species experience ontogenetic trophic niche shifts. The life-history of each species is described by a physiologically structured model and species identity...... there is a large scope for coexistence of two species, the scope for coexistence of three species is limited and we conclude that further trait differentiation is required for coexistence of more species-rich size-structured communities....

  8. A new species of Burkholderia isolated from sugarcane roots promotes plant growth

    Science.gov (United States)

    Paungfoo-Lonhienne, Chanyarat; Lonhienne, Thierry G A; Yeoh, Yun Kit; Webb, Richard I; Lakshmanan, Prakash; Chan, Cheong Xin; Lim, Phaik-Eem; Ragan, Mark A; Schmidt, Susanne; Hugenholtz, Philip

    2014-01-01

    Sugarcane is a globally important food, biofuel and biomaterials crop. High nitrogen (N) fertilizer rates aimed at increasing yield often result in environmental damage because of excess and inefficient application. Inoculation with diazotrophic bacteria is an attractive option for reducing N fertilizer needs. However, the efficacy of bacterial inoculants is variable, and their effective formulation remains a knowledge frontier. Here, we take a new approach to investigating diazotrophic bacteria associated with roots using culture-independent microbial community profiling of a commercial sugarcane variety (Q208A) in a field setting. We first identified bacteria that were markedly enriched in the rhizosphere to guide isolation and then tested putative diazotrophs for the ability to colonize axenic sugarcane plantlets (Q208A) and promote growth in suboptimal N supply. One isolate readily colonized roots, fixed N2 and stimulated growth of plantlets, and was classified as a new species, Burkholderia australis sp. nov. Draft genome sequencing of the isolate confirmed the presence of nitrogen fixation. We propose that culture-independent identification and isolation of bacteria that are enriched in rhizosphere and roots, followed by systematic testing and confirming their growth-promoting capacity, is a necessary step towards designing effective microbial inoculants. PMID:24350979

  9. HARMONIC INCLUSION FROM EDUCATION FOR PEACE AND COEXISTENCE PLANNING

    Directory of Open Access Journals (Sweden)

    Diana Genoveva Guerrero-Arce

    2016-01-01

    Full Text Available This article of reflection shown below is an analysis of how inclusion schemes change from a positive perspective from the peace studies and planning coexistence, considering elements of relevance as the conceptualization of discrimination, learned disabilities, public policies that attempt to include from the exclusion and the role of planning in the harmonic coexistence inclusion not only in school settings but socially, as an alternative that promotes respect for differences and consider redesigning programs rather than promote inclusion, wear combating discrimination and exclusion, resulting in more emerging preventive and educational actions. It is considering the need for listing proposals from a new paradigm that considers differences as elements that enrich the school environment and allow peaceful coexistence through diversity, which it is directly linked to that observed in the planning of coexistence that is taking place in schools in School Education of the State of Mexico inclusive education.

  10. Memory, Conviviality and Coexistence

    DEFF Research Database (Denmark)

    Duru, Deniz Neriman

    2016-01-01

    that postulates cohesion and conflict as rooted in ethnic and religious differences. It suggests ‘conviviality’ as the production of space, by arguing that hard times, tensions as well as sensorial pleasures produce a sense of belonging in a place, through shared ways of living. While memories of ‘coexistence......The article explores the narratives and memories of past diversity and current practices of conviviality to investigate how class, lifestyle and tastes affect the daily interactions between people belonging to different ethno-religious backgrounds. This chapter critiques ‘coexistence’ as a concept......’ emphasize the fragmentation of people into ethnic and religious groups as a consequence of the homogenization process in the post-Ottoman Turkish context, bitter sweet memories of conviviality create a sense of belonging to Burgaz....

  11. HARMONIC INCLUSION FROM EDUCATION FOR PEACE AND COEXISTENCE PLANNING

    OpenAIRE

    Diana Genoveva Guerrero-Arce; Eduardo Pérez-Archundia

    2016-01-01

    This article of reflection shown below is an analysis of how inclusion schemes change from a positive perspective from the peace studies and planning coexistence, considering elements of relevance as the conceptualization of discrimination, learned disabilities, public policies that attempt to include from the exclusion and the role of planning in the harmonic coexistence inclusion not only in school settings but socially, as an alternative that promotes respect for differences an...

  12. Biocontrol and Plant Growth Promotion Characterization of Bacillus Species Isolated from Calendula officinalis Rhizosphere.

    Science.gov (United States)

    Ait Kaki, Asma; Kacem Chaouche, Noreddine; Dehimat, Laid; Milet, Asma; Youcef-Ali, Mounia; Ongena, Marc; Thonart, Philippe

    2013-12-01

    The phenotypic and genotypic diversity of the plant growth promoting Bacillus genus have been widely investigated in the rhizosphere of various agricultural crops. However, to our knowledge this is the first report on the Bacillus species isolated from the rhizosphere of Calendula officinalis. 15 % of the isolated bacteria were screened for their important antifungal activity against Fusarium oxysporum, Botrytis cinerea, Aspergillus niger, Cladosporium cucumerinium and Alternaria alternata. The bacteria identification based on 16S r-RNA and gyrase-A genes analysis, revealed strains closely related to Bacillus amyloliquefaciens, B. velezensis, B. subtilis sub sp spizezenii and Paenibacillus polymyxa species. The electro-spray mass spectrometry coupled to liquid chromatography (ESI-LC MS) analysis showed that most of the Bacillus isolates produced the three lipopeptides families. However, the P. polymyxa (18SRTS) didn't produce any type of lipopeptides. All the tested Bacillus isolates produced cellulase but the protease activity was observed only in the B. amyloliquefaciens species (9SRTS). The Salkowsky colorimetric test showed that the screened bacteria synthesized 6-52 μg/ml of indole 3 acetic acid. These bacteria produced siderophores with more than 10 mm wide orange zones on chromazurol S. The greenhouse experiment using a naturally infested soil with Sclerotonia sclerotiorum showed that the B. amyloliquefaciens (9SRTS) had no significant (P > 0.05) effect on the pre-germination of the chickpea seeds. However, it increased the size of the chickpea plants and reduced the stem rot disease (P Bacillus strains isolated in this work may be further used as bioinoculants to improve the production of C. officinalis and other crop systems.

  13. PKCα promotes generation of reactive oxygen species via DUOX2 in hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Wang, Jiajun; Shao, Miaomiao; Liu, Min; Peng, Peike; Li, Lili; Wu, Weicheng; Wang, Lan; Duan, Fangfang; Zhang, Mingming; Song, Shushu; Jia, Dongwei; Ruan, Yuanyuan; Gu, Jianxin

    2015-01-01

    Hepatocellular carcinoma (HCC) remains the second leading cause of cancer-related death worldwide, and elevated rates of reactive oxygen species (ROS) have long been considered as a hallmark of almost all types of cancer including HCC. Protein kinase C alpha (PKCα), a serine/threonine kinase among conventional PKC family, is recognized as a major player in signal transduction and tumor progression. Overexpression of PKCα is commonly observed in human HCC and associated with its poor prognosis. However, how PKCα is involved in hepatocellular carcinogenesis remains not fully understood. In this study, we found that among the members of conventional PKC family, PKCα, but not PKCβI or βII, promoted ROS production in HCC cells. PKCα stimulated generation of ROS by up-regulating DUOX2 at post-transcriptional level. Depletion of DUOX2 abrogated PKCα-induced activation of AKT/MAPK pathways as well as cell proliferation, migration and invasion in HCC cells. Moreover, the expression of DUOX2 and PKCα was well positively correlated in both HCC cell lines and patient samples. Collectively, our findings demonstrate that PKCα plays a critical role in HCC development by inducing DUOX2 expression and ROS generation, and propose a strategy to target PKCα/DUOX2 as a potential adjuvant therapy for HCC treatment. - Highlights: • PKCα promotes the generation of ROS in hepatocellular carcinoma. • PKCα induces ROS production by up-regulating DUOX2 at post-transcriptional level. • DUOX2 is required for PKCα-induced AKT/MAPK activation and tumor progression in HCC. • The expression of PKCα is positively correlated with DUOX2 in HCC

  14. PKCα promotes generation of reactive oxygen species via DUOX2 in hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jiajun; Shao, Miaomiao; Liu, Min; Peng, Peike; Li, Lili; Wu, Weicheng; Wang, Lan [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, 200032 Shanghai (China); Duan, Fangfang [Institute of Biomedical Science, Fudan University, Shanghai (China); Zhang, Mingming; Song, Shushu [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, 200032 Shanghai (China); Jia, Dongwei, E-mail: jiadongwei@fudan.edu.cn [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, 200032 Shanghai (China); Ruan, Yuanyuan, E-mail: yuanyuanruan@fudan.edu.cn [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, 200032 Shanghai (China); Gu, Jianxin [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, 200032 Shanghai (China); Institute of Biomedical Science, Fudan University, Shanghai (China)

    2015-08-07

    Hepatocellular carcinoma (HCC) remains the second leading cause of cancer-related death worldwide, and elevated rates of reactive oxygen species (ROS) have long been considered as a hallmark of almost all types of cancer including HCC. Protein kinase C alpha (PKCα), a serine/threonine kinase among conventional PKC family, is recognized as a major player in signal transduction and tumor progression. Overexpression of PKCα is commonly observed in human HCC and associated with its poor prognosis. However, how PKCα is involved in hepatocellular carcinogenesis remains not fully understood. In this study, we found that among the members of conventional PKC family, PKCα, but not PKCβI or βII, promoted ROS production in HCC cells. PKCα stimulated generation of ROS by up-regulating DUOX2 at post-transcriptional level. Depletion of DUOX2 abrogated PKCα-induced activation of AKT/MAPK pathways as well as cell proliferation, migration and invasion in HCC cells. Moreover, the expression of DUOX2 and PKCα was well positively correlated in both HCC cell lines and patient samples. Collectively, our findings demonstrate that PKCα plays a critical role in HCC development by inducing DUOX2 expression and ROS generation, and propose a strategy to target PKCα/DUOX2 as a potential adjuvant therapy for HCC treatment. - Highlights: • PKCα promotes the generation of ROS in hepatocellular carcinoma. • PKCα induces ROS production by up-regulating DUOX2 at post-transcriptional level. • DUOX2 is required for PKCα-induced AKT/MAPK activation and tumor progression in HCC. • The expression of PKCα is positively correlated with DUOX2 in HCC.

  15. Growth promotion of Lactuca sativa in response to volatile organic compounds emitted from diverse bacterial species.

    Science.gov (United States)

    Fincheira, Paola; Venthur, Herbert; Mutis, Ana; Parada, Maribel; Quiroz, Andrés

    2016-12-01

    Agrochemicals are currently used in horticulture to increase crop production. Nevertheless, their indiscriminate use is a relevant issue for environmental and legal aspects. Alternative tools for reducing fertilizers and synthetic phytohormones are being investigated, such as the use of volatile organic compounds (VOCs) as growth inducers. Some soil bacteria, such as Pseudomonas and Bacillus, stimulate Arabidopsis and tobacco growth by releasing VOCs, but their effects on vegetables have not been investigated. Lactuca sativa was used as model vegetable to investigate bacterial VOCs as growth inducers. We selected 10 bacteria strains, belonging to Bacillus, Staphylococcus and Serratia genera that are able to produce 3-hydroxy-2-butanone (acetoin), a compound with proven growth promoting activity. Two-day old-seedlings of L. sativa were exposed to VOCs emitted by the selected bacteria grown in different media cultures for 7 days. The results showed that the VOCs released from the bacteria elicited an increase in the number of lateral roots, dry weight, root growth and shoot length, depending on the media used. Three Bacillus strains, BCT53, BCT9 and BCT4, were selected according to its their growth inducing capacity. The BCT9 strain elicited the greatest increases in dry weight and primary root length when L. sativa seedlings were subjected to a 10-day experiment. Finally, because acetoin only stimulated root growth, we suggest that other volatiles could be responsible for the growth promotion of L. sativa. In conclusion, our results strongly suggest that bacteria volatiles can be used as growth-inducers as alternative or complementary strategies for application in horticulture species. Copyright © 2016 Elsevier GmbH. All rights reserved.

  16. Growth Response and Tolerance to Heavy Metals of two Swamp Species inoculated with a Plant Growth-Promoting Rhizobacteria

    International Nuclear Information System (INIS)

    Rodriguez-Dorantes, A.; Labra-Cardon, D.; Guerrero-Zuniga, A.; Montes-Villafan, S.

    2009-01-01

    Due to the sensitivity and the sequestration ability of the microbial communities to heavy metals, microbes have been used for bioremediation. Recently the application of plant growth-promoting rhizobacteria (PGPR) for the bioremediation of this kind of contaminants has been done. This study evaluated the growth response and the tolerance to heavy metals of two swamp species. (Author)

  17. Developing a set of strong intronic promoters for robust metabolic engineering in oleaginous Rhodotorula (Rhodosporidium) yeast species.

    Science.gov (United States)

    Liu, Yanbin; Yap, Sihui Amy; Koh, Chong Mei John; Ji, Lianghui

    2016-11-25

    Red yeast species in the Rhodotorula/Rhodosporidium genus are outstanding producers of triacylglyceride and cell biomass. Metabolic engineering is expected to further enhance the productivity and versatility of these hosts for the production of biobased chemicals and fuels. Promoters with strong activity during oil-accumulation stage are critical tools for metabolic engineering of these oleaginous yeasts. The upstream DNA sequences of 6 genes involved in lipid biosynthesis or accumulation in Rhodotorula toruloides were studied by luciferase reporter assay. The promoter of perilipin/lipid droplet protein 1 gene (LDP1) displayed much stronger activity (4-11 folds) than that of glyceraldehyde-3-phosphate dehydrogenase gene (GPD1), one of the strongest promoters known in yeasts. Depending on the stage of cultivation, promoter of acetyl-CoA carboxylase gene (ACC1) and fatty acid synthase β subunit gene (FAS1) exhibited intermediate strength, displaying 50-160 and 20-90% levels of GPD1 promoter, respectively. Interestingly, introns significantly modulated promoter strength at high frequency. The incorporation of intron 1 and 2 of LDP1 (LDP1in promoter) enhanced its promoter activity by 1.6-3.0 folds. Similarly, the strength of ACC1 promoter was enhanced by 1.5-3.2 folds if containing intron 1. The intron 1 sequences of ACL1 and FAS1 also played significant regulatory roles. When driven by the intronic promoters of ACC1 and LDP1 (ACC1in and LDP1in promoter, respectively), the reporter gene expression were up-regulated by nitrogen starvation, independent of de novo oil biosynthesis and accumulation. As a proof of principle, overexpression of the endogenous acyl-CoA-dependent diacylglycerol acyltransferase 1 gene (DGA1) by LDP1in promoter was significantly more efficient than GPD1 promoter in enhancing lipid accumulation. Intronic sequences play an important role in regulating gene expression in R. toruloides. Three intronic promoters, LDP1in, ACC1in and FAS1in, are

  18. Phylogenetically diverse macrophyte community promotes species diversity of mobile epi-benthic invertebrates

    Science.gov (United States)

    Nakamoto, Kenta; Hayakawa, Jun; Kawamura, Tomohiko; Kodama, Masafumi; Yamada, Hideaki; Kitagawa, Takashi; Watanabe, Yoshiro

    2018-07-01

    Various aspects of plant diversity such as species diversity and phylogenetic diversity enhance the species diversity of associated animals in terrestrial systems. In marine systems, however, the effects of macrophyte diversity on the species diversity of associated animals have received little attention. Here, we sampled in a subtropical seagrass-seaweed mixed bed to elucidate the effect of the macrophyte phylogenetic diversity based on the taxonomic relatedness as well as the macrophyte species diversity on species diversity of mobile epi-benthic invertebrates. Using regression analyses for each macrophyte parameter as well as multiple regression analyses, we found that the macrophyte phylogenetic diversity (taxonomic diversity index: Delta) positively influenced the invertebrate species richness and diversity index (H‧). Although the macrophyte species richness and H‧ also positively influenced the invertebrate species richness, the best fit model for invertebrate species richness did not include them, suggesting that the macrophyte species diversity indirectly influenced invertebrate species diversity. Possible explanations of the effects of macrophyte Delta on the invertebrate species diversity were the niche complementarity effect and the selection effect. This is the first study which demonstrates that macrophyte phylogenetic diversity has a strong effect on the species diversity of mobile epi-benthic invertebrates.

  19. Does smoke promote seed germination in 10 Interior West Penstemon species?

    Science.gov (United States)

    Paula J. Fornwalt

    2015-01-01

    Recent research has shown that exposing seeds to smoke stimulates germination for a multitude of plant species, including several species in the genus Penstemon (Scrophulariaceae). I evaluated whether smoke, either alone or followed by 10 wk of stratification (moist prechilling), influenced germination for 10 Penstemon species native to the Interior West of North...

  20. Coexistence of a General Elliptic System in Population Dynamics

    DEFF Research Database (Denmark)

    Pedersen, Michael

    2004-01-01

    This paper is concerned with a strongly-coupled elliptic system representing a competitive interaction between two species. We give a sufficient condition for the existence of positive solutions. An example is also given to show that there is a coexistence of a steady state if the cross-diffusion......This paper is concerned with a strongly-coupled elliptic system representing a competitive interaction between two species. We give a sufficient condition for the existence of positive solutions. An example is also given to show that there is a coexistence of a steady state if the cross...

  1. Coexisting diseases of moyamoya vasculopathy.

    Science.gov (United States)

    Wei, Yi-Chia; Liu, Chi-Hung; Chang, Ting-Yu; Chin, Shy-Chyi; Chang, Chien-Hung; Huang, Kuo-Lun; Chang, Yeu-Jhy; Peng, Tsung-I; Lee, Tsong-Hai

    2014-07-01

    Several coexisting diseases have been reported in patients with moyamoya vasculopathy (MMV), but studies of quasi-moyamoya disease (quasi-MMD) are rare. This study aims to investigate the frequency of known coexisting diseases in patients with quasi-MMD and to compare quasi-MMD with moyamoya disease (MMD). Between 2000 and 2011, we retrospectively screened patients with International Classification of Diseases, Ninth Revision, code of 4375 (MMD) in the Health Information System of our hospital. The vascular images of each patient were confirmed by 2 neurologists and 1 neuroradiologist based on the diagnostic criteria of Japan Ministry of Health and Welfare. We excluded the patients with missing images and erroneous diagnosis. Demographics, coexisting diseases, laboratory data, treatment, and recurrent strokes were recorded. The eligible patients were divided into quasi-MMD and MMD groups according to the presence or absence of coexisting diseases. MMV was found in 90 patients including 37 (41.1%) quasi-MMD and 53 (58.9%) MMD. Atherosclerosis (32.4%) and thyroid disease (29.7%) were the leading coexisting diseases in quasi-MMD. Patients with MMD became symptomatic in a bimodal age distribution, whereas patients with quasi-MMD became symptomatic in a single-peak distribution. The prognosis of recurrent strokes was similar between quasi-MMD and MMD based on Kaplan-Meier analysis. A bimodal distribution of onset age was noted in MMD, whereas a single-peak distribution was found in quasi-MMD. Coexisting diseases were usually underevaluated but were more common than expected in patients with MMV. Atherosclerosis and thyroid diseases were the leading coexisting diseases in different preferential age. Copyright © 2014 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  2. Lettuce and rhizosphere microbiome responses to growth promoting Pseudomonas species under field conditions

    NARCIS (Netherlands)

    Cipriano, M.A.P.; Lupatini, M.; Santos, L.; Silva, M. da; Roesch, L.F.W.; Destefano, S.; Freitas, S.; Kuramae, E.E.

    2016-01-01

    Plant growth promoting rhizobacteria (PGPR) are well described and recommended for several crops worldwide. However, one of the most common problems in PGPR research is the difficulty in obtaining reproducible results. Furthermore, few studies have evaluated plant growth promotion and soil microbial

  3. Human land use promotes the abundance and diversity of exotic species on caribbean islands.

    Science.gov (United States)

    Jesse, Wendy A M; Behm, Jocelyn E; Helmus, Matthew R; Ellers, Jacintha

    2018-05-31

    Human land use causes major changes in species abundance and composition, yet native and exotic species can exhibit different responses to land use change. Native populations generally decline in human-impacted habitats while exotic species often benefit. In this study, we assessed the effects of human land use on exotic and native reptile diversity, including functional diversity, which relates to the range of habitat use strategies in biotic communities. We surveyed 114 reptile communities from localities that varied in habitat structure and human impact level on two Caribbean islands, and calculated species richness, overall abundance and evenness for every plot. Functional diversity indices were calculated using published trait data, which enabled us to detect signs of trait filtering associated with impacted habitats. Our results show that environmental variation among sampling plots was explained by two PCA ordination axes related to habitat structure (i.e. forest or non-forest) and human impact level (i.e. addition of man-made constructions such as roads and buildings). Several diversity indices were significantly correlated with the two PCA axes, but exotic and native species showed opposing responses. Native species reached the highest abundance in forests, while exotic species were absent in this habitat. Human impact was associated with an increase in exotic abundance and species richness, while native species showed no significant associations. Functional diversity was highest in non-forested environments on both islands, and further increased on St. Martin with the establishment of functionally unique exotic species in non-forested habitat. Habitat structure, rather than human impact, proved to be an important agent for environmental filtering of traits, causing divergent functional trait values across forested and non-forested environments. Our results illustrate the importance of considering various elements of land use when studying its impact on

  4. Horticultural markets promote alien species invasions: an Estonian case study of herbaceous perennials

    Directory of Open Access Journals (Sweden)

    Merle Ööpik

    2013-06-01

    Full Text Available Gardening is a popular pastime, but commercial horticulture is responsible for the introduction of alien species and contributes to invasions in a variety of ways. Although an extensive international literature is available on plant invasions, it is still important at the national level to examine the influence of local factors. Accordingly, 17 nurseries in Estonia that cultivated and sold perennial alien species were selected, and a list of species and prices was compiled. The relationships between species status, and factors such as their abundance in the wild were examined statistically. A qualitative list of the nationally problematic species among herbaceous perennials was also completed. A total of 880 taxa were recorded, of which 10.3% were native and 89.7% alien. In all, 87.3% of the alien species were still confined to cultivated areas. The ecological and socio-economic characteristics of the taxa were described, and lists of the families of casual, naturalised and invasive aliens were provided. Both native and increasing wild alien species have a very similar profile on the market. Alien species that are less expensive, widely available and have more cultivars per species on the market are also more likely to escape. The invasive status and abundance of escaped aliens in an area increases with residence time. In general, socio-economic factors create new and reflect previous propagule pressures from commercial horticulture, which continuously increase the likelihood of alien species surviving and invading new areas. Our findings suggest that these national socio-economic market-related factors explain much of the invasiveness of various perennial ornamental species, and therefore regional and national authorities urgently need to regulate and control the ornamental plant trade to diminish the risk of new invasions.

  5. Shape coexistence in selenium isotopes

    International Nuclear Information System (INIS)

    Liu Ying; Cao Zhongbin; Xu Furong

    2010-01-01

    Nuclear shape change and shape coexistence in the Selenium isotopes have been investigated by Total-Routhian-Surface (TRS) calculations. It is found that nuclear shapes vary significantly with increasing neutron number. The TRS calculations for the ground states of 66,72,92,94 Se isotopes show that both neutron-deficient and neutron-dripline Selenium isotopes have oblate and prolate shape coexistence. The cranking shell-model calculations for 72,94 Se give that prolate and oblate shape coexistence in low rotational frequency. However, oblate rotational bands disappear and prolate rotational bands become yrast bands with increasing rotational frequency, which is due to the intrusion of the g 9/2 orbitals. (authors)

  6. Public Spaces - Coexistence and Participation

    Science.gov (United States)

    Stasiak, Anna; Wojtowicz-Jankowska, Dorota

    2017-10-01

    The paper is an attempt to answer two questions: (1) how to develop positive social relations and citizenship among residents of cities in Poland and (2) how suitable shaping of public space affects the activation and integration of local residents. The specificity of the postwar process of urbanization in Poland - a country traditionally agricultural - was its political dimension (forced “nationalisation” of agriculture and industrialization of the country) ignoring the socio-cultural determinants and consequences of this process resulting in disappearance of traditional social bonds. According to forecasts, the number of urban dwellers is expected to grow by the year 2050 and increase up to 70 percent of the population. Such a rapid urban sprawl was not accompanied by appropriate social policies; the result was a low level of social organization and of a sense of citizenship. There are various attempts to change this situation. One of them is the development of a system of urban public spaces, according to the needs and preferences of residents (i.e. promotion of physical activity in public areas, introducing elements of art to the common external space, encouraging users to contribute to their surroundings and introducing the appearance of temporary, often cyclical, attractions). Regular interactions between people in public spaces are conducive to developing positive social relationships. Quality and development of the local community is dependent on the quality of space in which it is built. For this reason, attention has been paid to the factors influencing the perception of public space, i.e. geographical and natural conditions, cultural and architectural (arrangement, the availability and condition of these spaces). In the article, the examples of different types of Polish public spaces are described - permanent and temporal recreational spaces (including summer activities and winter attractions). Attempt has also been made to give an answer to the

  7. Genetic Diversity of Nitrogen-Fixing and Plant Growth Promoting Pseudomonas Species Isolated from Sugarcane Rhizosphere.

    Science.gov (United States)

    Li, Hai-Bi; Singh, Rajesh K; Singh, Pratiksha; Song, Qi-Qi; Xing, Yong-Xiu; Yang, Li-Tao; Li, Yang-Rui

    2017-01-01

    The study was designed to isolate and characterize Pseudomonas spp. from sugarcane rhizosphere, and to evaluate their plant- growth- promoting (PGP) traits and nitrogenase activity. A biological nitrogen-fixing microbe has great potential to replace chemical fertilizers and be used as a targeted biofertilizer in a plant. A total of 100 isolates from sugarcane rhizosphere, belonging to different species, were isolated; from these, 30 isolates were selected on the basis of preliminary screening, for in vitro antagonistic activities against sugarcane pathogens and for various PGP traits, as well as nitrogenase activity. The production of IAA varied from 312.07 to 13.12 μg mL -1 in tryptophan supplemented medium, with higher production in AN15 and lower in CN20 strain. The estimation of ACC deaminase activity, strains CY4 and BA2 produced maximum and minimum activity of 77.0 and 15.13 μmoL mg -1 h -1 . For nitrogenase activity among the studied strains, CoA6 fixed higher and AY1 fixed lower in amounts (108.30 and 6.16 μmoL C 2 H 2 h -1 mL -1 ). All the strains were identified on the basis of 16S rRNA gene sequencing, and the phylogenetic diversity of the strains was analyzed. The results identified all strains as being similar to Pseudomonas spp. Polymerase chain reaction (PCR) amplification of nifH and antibiotic genes was suggestive that the amplified strains had the capability to fix nitrogen and possessed biocontrol activities. Genotypic comparisons of the strains were determined by BOX, ERIC, and REP PCR profile analysis. Out of all the screened isolates, CY4 ( Pseudomonas koreensis ) and CN11 ( Pseudomonas entomophila ) showed the most prominent PGP traits, as well as nitrogenase activity. Therefore, only these two strains were selected for further studies; Biolog profiling; colonization through green fluorescent protein (GFP)-tagged bacteria; and nifH gene expression using quantitative real-time polymerase chain reaction (qRT-PCR) analysis. The Biolog

  8. Sex allocation promotes the stable co-occurrence of competitive species

    Science.gov (United States)

    Kobayashi, Kazuya

    2017-03-01

    Biodiversity has long been a source of wonder and scientific curiosity. Theoretically, the co-occurrence of competitive species requires niche differentiation, and such differences are well known; however, the neutral theory, which assumes the equivalence of all individuals regardless of the species in a biological community, has successfully recreated observed patterns of biodiversity. In this research, the evolution of sex allocation is demonstrated to be the key to resolving why the neutral theory works well, despite the observed species differences. The sex allocation theory predicts that female-biased allocation evolves in species in declining density and that this allocation improves population growth, which should lead to an increase in density. In contrast, when the density increases, a less biased allocation evolves, which reduces the population growth rate and leads to decreased density. Thus, sex allocation provides a buffer against species differences in population growth. A model incorporating this mechanism demonstrates that hundreds of species can co-occur over 10,000 generations, even in homogeneous environments, and reproduces the observed patterns of biodiversity. This study reveals the importance of evolutionary processes within species for the sustainability of biodiversity. Integrating the entire biological process, from genes to community, will open a new era of ecology.

  9. Lettuce and rhizosphere microbiome responses to growth promoting Pseudomonas species under field conditions.

    Science.gov (United States)

    Cipriano, Matheus A P; Lupatini, Manoeli; Lopes-Santos, Lucilene; da Silva, Márcio J; Roesch, Luiz F W; Destéfano, Suzete A L; Freitas, Sueli S; Kuramae, Eiko E

    2016-12-01

    Plant growth promoting rhizobacteria are well described and recommended for several crops worldwide. However, one of the most common problems in research into them is the difficulty in obtaining reproducible results. Furthermore, few studies have evaluated plant growth promotion and soil microbial community composition resulting from bacterial inoculation under field conditions. Here we evaluated the effect of 54 Pseudomonas strains on lettuce (Lactuca sativa) growth. The 12 most promising strains were phylogenetically and physiologically characterized for plant growth-promoting traits, including phosphate solubilization, hormone production and antagonism to pathogen compounds, and their effect on plant growth under farm field conditions. Additionally, the impact of beneficial strains on the rhizospheric bacterial community was evaluated for inoculated plants. The strains IAC-RBcr4 and IAC-RBru1, with different plant growth promoting traits, improved lettuce plant biomass yields up to 30%. These two strains also impacted rhizosphere bacterial groups including Isosphaera and Pirellula (phylum Planctomycetes) and Acidothermus, Pseudolabrys and Singusphaera (phylum Actinobacteria). This is the first study to demonstrate consistent results for the effects of Pseudomonas strains on lettuce growth promotion for seedlings and plants grown under tropical field conditions. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. Promotion of adventitious root formation of difficult-to-root hardwood tree species

    Science.gov (United States)

    Paula M. Pijut; Keith E. Woeste; Charles H. Michler

    2011-01-01

    North American hardwood tree species, such as alder (Alnus spp.), ash (Fraxinus spp.), basswood (Tilia spp.), beech (Fagus spp.), birch (Betula spp.), black cherry (Prunus seratina), black walnut (Juglans nigra), black willow (...

  11. Local coexistance of different phases

    International Nuclear Information System (INIS)

    Narnhofer, H.

    1982-01-01

    Under intuitively reasonable assumptions it is shown that in two dimensions different phases cannot exist locally. In three dimensions we discuss the possibility of local coexistance of districts with different magnetization for the Heisenberg ferromagnet and show that an interaction that breaks rotational invariance is necessary for this phenomenon. (Author)

  12. A specter of coexistence: Is centrifugal community organization haunted by the ghost of competition?

    Science.gov (United States)

    Wasserberg, Gideon; Kotler, B.P.; Morris, D.W.; Abramsky, Z.

    2006-01-01

    In a centrifugally organized community species prefer the same habitat (called "core") but differ in their secondary habitat preferences. The first model of centrifugal community organization (CCO) predicted that optimally foraging, symmetrically competing species would share use of the core habitat at all density combinations. But one might also assume that the competition in the core habitat is asymmetrical, that is, that one of the species (the dominant) has a behavioral advantage therein. In this study, we asked how should habitat use evolve in a centrifugally organized community if its species compete asymmetrically in the core habitat? To address this question we developed an "isoleg model". The model predicts that in a centrifugally organized community, asymmetric competition promotes the use of the core habitat exclusively by the dominant species at most points in the state space. The separation of the core habitat use by the species ("the ghost of competition past") may be either complete or partial ("partial ghost"), and behavior at the stable competitive equilibrium between the species could determine whether coexistence should occur at the "complete-" or the "partial ghost" regions. This version of CCO should be a common feature of competitive systems.

  13. Coexistence and Habitat Preference of Two Honeyeaters and a Sunbird on Lombok, Indonesia

    DEFF Research Database (Denmark)

    Carstensen, Daniel Wisbech; Sweeny, Redmond; Ehlers, Bodil

    2011-01-01

    On the island of Lombok, Indonesia, three nectarivorous birds partially coexist: the two closely related and very similar Lichmera honeyeaters and a sunbird (Cinnyris jugularis). We investigated how these species segregated ecologically in areas where they coexisted by evaluating foraging visits...

  14. Lactobacillus species as biomarkers and agents that can promote various aspects of vaginal health

    Directory of Open Access Journals (Sweden)

    Mariya Ivanova Petrova

    2015-03-01

    Full Text Available The human body is colonized by a vast number of microorganisms collectively referred to as the human microbiota. One of the main microbiota body sites is the female genital tract, commonly dominated by Lactobacillus spp., in approximately 70% of women. Each individual species can constitute approximately 99% of the ribotypes observed in any individual woman. The most frequently isolated species are Lactobacillus crispatus, Lactobacillus gasseri, Lactobacillus jensenii and Lactobacillus iners. Residing at the port of entry of bacterial and viral pathogens, the vaginal Lactobacillus species can create a barrier against pathogen invasion since mainly products of their metabolism secreted in the cervicovaginal fluid can play an important role in the inhibition of bacterial and viral infections. Therefore, a Lactobacillus-dominated microbiota appears to be a good biomarker for a healthy vaginal ecosystem. This balance can be rapidly altered during processes such as menstruation, sexual activity, pregnancy and various infections. An abnormal vaginal microbiota is characterized by an increased diversity of microbial species, leading to a condition known as bacterial vaginosis. Information on the vaginal microbiota can be gathered from the analysis of cervicovaginal fluid, by using the Nugent scoring or the Amsel’s criteria, or at the molecular level by investigating the number and type of Lactobacillus species. However, when translating this to the clinical setting, it should be noted that the absence of a Lactobacillus-dominated microbiota does not appear to directly imply a diseased condition or dysbiosis. Nevertheless, the widely documented beneficial role of vaginal Lactobacillus species demonstrates the potential of data on the composition and activity of lactobacilli as biomarkers for vaginal health. The substantiation and further validation of such biomarkers will allow the design of better targeted probiotic strategies.

  15. Coexistence and Survival in Conservative Lotka-Volterra Networks

    Science.gov (United States)

    Knebel, Johannes; Krüger, Torben; Weber, Markus F.; Frey, Erwin

    2013-04-01

    Analyzing coexistence and survival scenarios of Lotka-Volterra (LV) networks in which the total biomass is conserved is of vital importance for the characterization of long-term dynamics of ecological communities. Here, we introduce a classification scheme for coexistence scenarios in these conservative LV models and quantify the extinction process by employing the Pfaffian of the network’s interaction matrix. We illustrate our findings on global stability properties for general systems of four and five species and find a generalized scaling law for the extinction time.

  16. Can magnetism and superconductivity coexist

    International Nuclear Information System (INIS)

    Ishikawa, M.

    1982-01-01

    Recent syntheses of rare earth (RE) ternary superconductors such as (RE)Mo 6 X 8 (X=S or Se) and (RE)Rh 4 B 4 have provided the first opportunity to explore the interaction between magnetism and superconductivity in detail owing to their particular crystal structure. The regular sublattice of the rare-earth ions in these new ternary compounds undergoes a ferro- or antiferromagnetic phase transition in the superconducting state. If the transition is antiferromagnetic, the superconductivity is preserved so that true coexistence results. If it is ferromagnetic, on the other hand, the superconductivity eventually gives way to uniform ferromagnetism at low temperatures. However, recent theories predict several possible states of coexistence even in ferromagnetic superconductors. This article reviews aspects of these new phase transitions in ternary superconductors. (author)

  17. Shape coexistence in 153Ho

    Science.gov (United States)

    Pramanik, Dibyadyuti; Sarkar, S.; Saha Sarkar, M.; Bisoi, Abhijit; Ray, Sudatta; Dasgupta, Shinjinee; Chakraborty, A.; Krishichayan, Kshetri, Ritesh; Ray, Indrani; Ganguly, S.; Pradhan, M. K.; Ray Basu, M.; Raut, R.; Ganguly, G.; Ghugre, S. S.; Sinha, A. K.; Basu, S. K.; Bhattacharya, S.; Mukherjee, A.; Banerjee, P.; Goswami, A.

    2016-08-01

    The high-spin states in 153Ho have been studied by the La57(20Ne139,6 n ) reaction at a projectile energy of 139 MeV at the Variable Energy Cyclotron Centre (VECC), Kolkata, India, utilizing an earlier campaign of the Indian National Gamma Array (INGA) setup. Data from γ -γ coincidence, directional correlation, and polarization measurements have been analyzed to assign and confirm the spins and parities of the levels. We have suggested a few additions and revisions of the reported level scheme of 153Ho. The RF-γ time difference spectra have been useful to confirm the half-life of an isomer in this nucleus. From the comparison of experimental and theoretical results, it is found that there are definite indications of shape coexistence in this nucleus. The experimental and calculated lifetimes of several isomers have been compared to follow the coexistence and evolution of shape with increasing spin.

  18. Tree species diversity promotes aboveground carbon storage through functional diversity and functional dominance.

    Science.gov (United States)

    Mensah, Sylvanus; Veldtman, Ruan; Assogbadjo, Achille E; Glèlè Kakaï, Romain; Seifert, Thomas

    2016-10-01

    The relationship between biodiversity and ecosystem function has increasingly been debated as the cornerstone of the processes behind ecosystem services delivery. Experimental and natural field-based studies have come up with nonconsistent patterns of biodiversity-ecosystem function, supporting either niche complementarity or selection effects hypothesis. Here, we used aboveground carbon (AGC) storage as proxy for ecosystem function in a South African mistbelt forest, and analyzed its relationship with species diversity, through functional diversity and functional dominance. We hypothesized that (1) diversity influences AGC through functional diversity and functional dominance effects; and (2) effects of diversity on AGC would be greater for functional dominance than for functional diversity. Community weight mean (CWM) of functional traits (wood density, specific leaf area, and maximum plant height) were calculated to assess functional dominance (selection effects). As for functional diversity (complementarity effects), multitrait functional diversity indices were computed. The first hypothesis was tested using structural equation modeling. For the second hypothesis, effects of environmental variables such as slope and altitude were tested first, and separate linear mixed-effects models were fitted afterward for functional diversity, functional dominance, and both. Results showed that AGC varied significantly along the slope gradient, with lower values at steeper sites. Species diversity (richness) had positive relationship with AGC, even when slope effects were considered. As predicted, diversity effects on AGC were mediated through functional diversity and functional dominance, suggesting that both the niche complementarity and the selection effects are not exclusively affecting carbon storage. However, the effects were greater for functional diversity than for functional dominance. Furthermore, functional dominance effects were strongly transmitted by CWM of

  19. Brazilian underutilised species to promote dietary diversity, local food procurement, and biodiversity conservation: a food composition gap analysis

    Directory of Open Access Journals (Sweden)

    Daniela Moura de Oliveira Beltrame, PhD

    2018-05-01

    Full Text Available Background: Brazil is home to a large portion of the world's biodiversity, but, paradoxically, the country's agriculture and food security are very reliant on exotic or introduced crops or species. Native species are being neglected and forgotten with natural landscapes and traditional foods being replaced by monocultures of commodity crops and pasture for livestock, causing habitat and biodiversity loss. At the same time, Brazil faces dietary simplification and high levels of malnutrition. Much of the neglected native biodiversity is highly nutritious and exploring these food sources could help provide sustainable solutions to diversifying diets, tackling malnutrition problems, and promoting agricultural development through local food procurement, while also promoting biodiversity conservation and climate change adaptation and resilience. However, notable knowledge and evidence gaps still need to be addressed to better integrate biodiversity for enhancing food and nutrition security, including scientific data on the nutritional value and composition of native underutilised species. In Brazil, the Biodiversity for Food and Nutrition (BFN project generated food composition data, developed recipes, and increased appreciation and awareness of the value of underutilised, nutrient-rich biodiversity through strategic research partnerships with universities and research institutes. Methods: For this food composition gap analysis of native Brazilian biodiversity, the BFN project established partnerships with universities and research institutes for the generation of food composition data (macronutrients, vitamins, and minerals and the development of recipes for 70 native underutilised species of fruits and vegetables of economic potential. Food composition data was gathered by doing a literature review, using compilation methods developed by the Food and Agriculture Organization of the United Nations and the International Network for Food Data Systems

  20. Endangered Species

    Science.gov (United States)

    EPA's Endangered Species Protection Program helps promote recovery of listed species. The ESPP determines if pesticide use in a geographic area may affect any listed species. Find needed limits on pesticide use in Endangered Species Protection Bulletins.

  1. Multi-scale habitat modification by coexisting ecosystem engineers drives spatial separation of macrobenthic functional groups

    NARCIS (Netherlands)

    Donadi, S.; van der Heide, T.; Piersma, T.; van der Zee, E.M.; Weerman, E.J.; van de Koppel, J.; Olff, H.; Devine, C.; Hernawan, U. E.; Boers, M.; Planthof, L.; Eriksson, B.K.

    2015-01-01

    By changing habitat conditions, ecosystem engineers increase niche diversity and have profound effects on the distribution and abundances of other organisms. Although many ecosystems contain several engineering species, it is still unclear how the coexistence of multiple engineers affects the

  2. Genotypic diversity of an invasive plant species promotes litter decomposition and associated processes.

    Science.gov (United States)

    Wang, Xiao-Yan; Miao, Yuan; Yu, Shuo; Chen, Xiao-Yong; Schmid, Bernhard

    2014-03-01

    Following studies that showed negative effects of species loss on ecosystem functioning, newer studies have started to investigate if similar consequences could result from reductions of genetic diversity within species. We tested the influence of genotypic richness and dissimilarity (plots containing one, three, six or 12 genotypes) in stands of the invasive plant Solidago canadensis in China on the decomposition of its leaf litter and associated soil animals over five monthly time intervals. We found that the logarithm of genotypic richness was positively linearly related to mass loss of C, N and P from the litter and to richness and abundance of soil animals on the litter samples. The mixing proportion of litter from two sites, but not genotypic dissimilarity of mixtures, had additional effects on measured variables. The litter diversity effects on soil animals were particularly strong under the most stressful conditions of hot weather in July: at this time richness and abundance of soil animals were higher in 12-genotype litter mixtures than even in the highest corresponding one-genotype litter. The litter diversity effects on decomposition were in part mediated by soil animals: the abundance of Acarina, when used as covariate in the analysis, fully explained the litter diversity effects on mass loss of N and P. Overall, our study shows that high genotypic richness of S. canadensis leaf litter positively affects richness and abundance of soil animals, which in turn accelerate litter decomposition and P release from litter.

  3. Mesotrione herbicide promotes biochemical changes and DNA damage in two fish species

    Directory of Open Access Journals (Sweden)

    L.D.S. Piancini

    2015-01-01

    Full Text Available Mesotrione is one of the new herbicides that have emerged as an alternative after the ban of atrazine in the European Union. To our knowledge, any work using genetic or biochemical biomarkers was performed in any kind of fish evaluating the toxicity of this compound. The impact of acute (96 h exposure to environmentally relevant mesotrione concentrations (1.8, 7, 30, 115 e 460 μg L−1 were evaluated on the liver of Oreochorimis niloticus and Geophagus brasiliensis by assessing the activity of superoxide dismutase (SOD, glutathione peroxidase (GPx and glutathione-S- transferase (GST, the levels of reduced glutathione (GSH, carbonyl assays (PCO and lipid peroxide (LPO as well as the DNA damage to erithrocytes, liver and gills through the comet assay. We observed an increase in the concentration of GSH and the GPx activity in O. niloticus, and the GST and SOD activity in G. brasiliensis. We found significant increase in DNA damage in all tissues in both species. The results indicated that the acute exposure to mesotrione can induce oxidative stress and DNA damage in both species.

  4. A mixture of Lactobacillus species isolated from traditional fermented foods promote recovery from antibiotic-induced intestinal disruption in mice.

    Science.gov (United States)

    Shi, Y; Zhao, X; Zhao, J; Zhang, H; Zhai, Q; Narbad, A; Chen, W

    2018-03-01

    This study evaluated the antibiotic-induced changes in microbial ecology, intestinal dysbiosis and low-grade inflammation; and the combined effect of four different Lactobacillus species on recovery of microbiota composition and improvement of gut barrier function in mice. Administration of the antibiotic ampicillin for 2 weeks decreased microbial community diversity, induced caecum tumefaction and increased gut permeability in mice. Application of a probiotic cocktail of four Lactobacillus species (JUP-Y4) modulated the microbiota community structure and promoted the abundance of potentially beneficial bacteria such as Akkermansia. Ampicillin administration led to a decline in Bacteroidetes from 46·6 ± 3·91% to 0·264 ± 0·0362%; the addition of JUP-Y4 restored this to 41·4 ± 2·87%. This probiotic supplementation was more effective than natural restoration, where the levels of Bacteroidetes were only restored to 29·3 ± 2·07%. Interestingly, JUP-Y4 treatment was more effective in the restoration of microbiota in faecal samples than in caecal samples. JUP-Y4 also significantly reduced the levels of d-lactate and endotoxin (lipopolysaccharide, LPS) in the serum of mice, and increased the expression of tight-junction proteins while reducing the production of inflammatory cytokines (TNF-α, IL-6, MCP-1, IFN-γ and IL-1β) in the ileum and the colon of antibiotic-treated mice. JUP-Y4 not only promoted recovery from antibiotic-induced gut dysbiosis, but also enhanced the function of the gut barrier, reduced inflammation and lowered levels of circulating endotoxin in mice. Consumption of a mixture of Lactobacillus species may encourage faster recovery from antibiotic-induced gut dysbiosis and gut microbiota-related immune disturbance. © 2018 The Society for Applied Microbiology.

  5. Restraining reactive oxygen species in Listeria monocytogenes promotes the apoptosis of glial cells.

    Science.gov (United States)

    Li, Sen; Li, Yixuan; Chen, Guowei; Zhang, Jingchen; Xu, Fei; Wu, Man

    2017-07-01

    Listeria monocytogenes is a facultative anaerobic foodborne pathogen that can traverse the blood-brain barrier and cause brain infection. L. monocytogenes infection induces host cell apoptosis in several cell types. In this study, we investigated the apoptosis of human glioma cell line U251 invaded by L. monocytogenes and evaluated the function of bacterial reactive oxygen species (ROS) during infection. Bacterial ROS level was reduced by carrying out treatment with N-acetyl cysteine (NAC) and diphenyleneiodonium chloride (DPI). After infection, the apoptosis of U251 cells was examined by flow cytometry assay and propidium iodide staining. DPI and NAC efficiently decreased ROS level in L. monocytogenes without affecting bacterial growth. Moreover, the apoptosis of glial cells was enhanced upon invasion of DPI- and NAC-pretreated L. monocytogenes. Results indicate that the apoptosis of glial cells can be induced by L. monocytogenes, and that the inhibition of bacterial ROS increases the apoptosis of host cells.

  6. Hemoglobin fructation promotes heme degradation through the generation of endogenous reactive oxygen species

    Science.gov (United States)

    Goodarzi, M.; Moosavi-Movahedi, A. A.; Habibi-Rezaei, M.; Shourian, M.; Ghourchian, H.; Ahmad, F.; Farhadi, M.; Saboury, A. A.; Sheibani, N.

    2014-09-01

    Protein glycation is a cascade of nonenzymatic reactions between reducing sugars and amino groups of proteins. It is referred to as fructation when the reducing monosaccharide is fructose. Some potential mechanisms have been suggested for the generation of reactive oxygen species (ROS) by protein glycation reactions in the presence of glucose. In this state, glucose autoxidation, ketoamine, and oxidative advance glycation end products (AGEs) formation are considered as major sources of ROS and perhaps heme degradation during hemoglobin glycation. However, whether fructose mediated glycation produces ROS and heme degradation is unknown. Here we report that ROS (H2O2) production occurred during hemoglobin fructation in vitro using chemiluminescence methods. The enhanced heme exposure and degradation were determined using UV-Vis and fluorescence spectrophotometry. Following accumulation of ROS, heme degradation products were accumulated reaching a plateau along with the detected ROS. Thus, fructose may make a significant contribution to the production of ROS, glycation of proteins, and heme degradation during diabetes.

  7. Asymmetrical Competition between Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae Coexisting in Breeding Sites

    Directory of Open Access Journals (Sweden)

    Juan C. Santana-Martínez

    2017-10-01

    Full Text Available Aedes aegypti and Culex quinquefasciatus are mosquito vectors for several tropical diseases that represent a current public health problem. The ecological requirements for each species are different, however, both species show high biological adaptability, which promotes their coexistence in the same breeding sites. The purpose of this study was to assess the effect of larval association between Ae. aegypti and Cx. quinquefasciatus under different laboratory conditions of food supply and temperature, and under field simulated conditions like peridomestic containers. Our findings showed that under field simulated conditions there was no asymmetrical competition in mixed cultures with the different Cx. quinquefasciatus/Ae. aegypti ratios tested. However, under laboratory conditions in which different doses of food supply were evaluated, it was observed that competition between the two species takes place. Larval coexistence under food scarcity conditions (0.95 mg/larva showed that Ae. aegypti had a greater adult emergence than Cx. quinquefasciatus and was capable of depriving Cx. quinquefasciatus of the food needed to complete metamorphosis. In an intermediate dose of food (1.9 mg/larva, the dry weight of Cx. quinquefasciatus adults decreased, and their larval development time increased when Cx. quinquefasciatus/Ae. aegypti ratio was low. Also, a temperature effect was assessed demonstrating that Cx. quinquefasciatus was more vulnerable to changes in temperature. We suggest that Ae. aegypti is more successful in exploiting microhabitats when food is scarce, due to its scrape active feeding habitats and fast larval development times. Therefore, in conditions of food paucity both species will compete, and Ae. aegypti larvae will prevail.

  8. A Single Sphingomyelin Species Promotes Exosomal Release of Endoglin into the Maternal Circulation in Preeclampsia.

    Science.gov (United States)

    Ermini, Leonardo; Ausman, Jonathan; Melland-Smith, Megan; Yeganeh, Behzad; Rolfo, Alessandro; Litvack, Michael L; Todros, Tullia; Letarte, Michelle; Post, Martin; Caniggia, Isabella

    2017-09-22

    Preeclampsia (PE), an hypertensive disorder of pregnancy, exhibits increased circulating levels of a short form of the auxillary TGF-beta (TGFB) receptor endoglin (sENG). Until now, its release and functionality in PE remains poorly understood. Here we show that ENG selectively interacts with sphingomyelin(SM)-18:0 which promotes its clustering with metalloproteinase 14 (MMP14) in SM-18:0 enriched lipid rafts of the apical syncytial membranes from PE placenta where ENG is cleaved by MMP14 into sENG. The SM-18:0 enriched lipid rafts also contain type 1 and 2 TGFB receptors (TGFBR1 and TGFBR2), but not soluble fms-like tyrosine kinase 1 (sFLT1), another protein secreted in excess in the circulation of women with PE. The truncated ENG is then released into the maternal circulation via SM-18:0 enriched exosomes together with TGFBR1 and 2. Such an exosomal TGFB receptor complex could be functionally active and block the vascular effects of TGFB in the circulation of PE women.

  9. C4 Photosynthesis Promoted Species Diversification during the Miocene Grassland Expansion

    Science.gov (United States)

    Spriggs, Elizabeth L.; Christin, Pascal-Antoine; Edwards, Erika J.

    2014-01-01

    Identifying how organismal attributes and environmental change affect lineage diversification is essential to our understanding of biodiversity. With the largest phylogeny yet compiled for grasses, we present an example of a key physiological innovation that promoted high diversification rates. C4 photosynthesis, a complex suite of traits that improves photosynthetic efficiency under conditions of drought, high temperatures, and low atmospheric CO2, has evolved repeatedly in one lineage of grasses and was consistently associated with elevated diversification rates. In most cases there was a significant lag time between the origin of the pathway and subsequent radiations, suggesting that the ‘C4 effect’ is complex and derives from the interplay of the C4 syndrome with other factors. We also identified comparable radiations occurring during the same time period in C3 Pooid grasses, a diverse, cold-adapted grassland lineage that has never evolved C4 photosynthesis. The mid to late Miocene was an especially important period of both C3 and C4 grass diversification, coincident with the global development of extensive, open biomes in both warm and cool climates. As is likely true for most “key innovations”, the C4 effect is context dependent and only relevant within a particular organismal background and when particular ecological opportunities became available. PMID:24835188

  10. Bird on the wire: Landscape planning considering costs and benefits for bird populations coexisting with power lines.

    Science.gov (United States)

    D'Amico, Marcello; Catry, Inês; Martins, Ricardo C; Ascensão, Fernando; Barrientos, Rafael; Moreira, Francisco

    2018-02-24

    Power-line grids are increasingly expanding worldwide, as well as their negative impacts on avifauna, namely the direct mortality through collision and electrocution, the reduction of breeding performance, and the barrier effect. On the other hand, some bird species can apparently benefit from the presence of power lines, for example perching for hunting purposes or nesting on electricity towers. In this perspective essay, we reviewed the scientific literature on both costs and benefits for avifauna coexisting with power lines. Overall, we detected a generalized lack of studies focusing on these costs or benefits at a population level. We suggest that a switch in research approach to a larger spatio-temporal scale would greatly improve our knowledge about the actual effects of power lines on bird populations. This research approach would facilitate suitable landscape planning encompassing both mitigation of costs and promotion of benefits for bird populations coexisting with power lines. For example, the strategic route planning of electricity infrastructures would limit collision risk or barrier effects for threatened bird populations. Concurrently, this strategic route planning would promote the range expansion of threatened populations of other bird species, by providing nesting structures in treeless but potentially suitable landscapes. We suggest establishing a collaborative dialogue among the scientific community, governments, and electricity companies, with the aim to produce a win-win scenario in which both biodiversity conservation and infrastructure development are integrated in a common strategy.

  11. Issues On Religious Coexistence Tolerance In Albania 1912-1945

    Directory of Open Access Journals (Sweden)

    Ahmed Kalaja

    2015-08-01

    Full Text Available The religious tolerance is one of the rarest values of the tradition of the Albanian people. It is widely accepted that Albanian people are well known about these values about an excellent coexistence among the believers of different religious communities that are in Albania mainly Muslims and Christians. In this study we bring the essentials of this phenomenon promotional roots of these values while viewed from a previously untreated point of view and in an attempt to answer the questions Where does it stem from the religious coexistence in Albania What are the main promoters of this phenomenon What has been the attitude of the religious clergy in Albania Have they been and are the imams and priests the promotion of tolerance and religious coexistence in Albania These are some of the questions answered in this modest study focusing on how nice and with how much delicacy the lectures of the Clergy have addressed this issue to the faithful or to the world in general. Since they enjoyed undisputable reputation and influence in the majority of the population in the most critical moments of national history the leaders of Muslims believers not only have promoted tolerance and religious coexistence but they have considered the believers of other faiths as brothers preaching this conviction in front of their Muslim believers. These preachings were firstly begun by VehbiDibra who was the first Chairman of the Muslims and all clerics without exception to this day. Also unforgettable are the sermons of priests like Fr. GjergjFishta Fr. ShtjefnGjeovi or Metropolitan VisarionXhuvani to conclude with pearls of Orthodox priest Fan S. Noli who amazed the world with his three speeches in front of world leaders the League of Nations being representative of all Albanians although Orthodox believers were only 20 of the population.

  12. Growth promotion and inhibition of the Amazonian wild rice species Oryza grandiglumis to survive flooding.

    Science.gov (United States)

    Okishio, Takuma; Sasayama, Daisuke; Hirano, Tatsuya; Akimoto, Masahiro; Itoh, Kazuyuki; Azuma, Tetsushi

    2014-09-01

    In Asian cultivated rice (Oryza sativa), distinct mechanisms to survive flooding are activated in two groups of varieties. Submergence-tolerant rice varieties possessing the SUBMERGENCE1A (SUB1A) gene display reduced growth during flash floods at the seedling stage and resume growth after the flood recedes, whereas deepwater rice varieties possessing the SNORKEL1 (SK1) and SNORKEL2 (SK2) genes display enhanced growth based on internodal elongation during prolonged submergence at the mature stage. In this study, we investigated the occurrence of these growth responses to submergence in the wild rice species Oryza grandiglumis, which is native to the Amazon floodplains. When subjected to gradual submergence, adult plants of O. grandiglumis accessions showed enhanced internodal elongation with rising water level and their growth response closely resembled that of deepwater varieties of O. sativa with high floating capacity. On the other hand, when subjected to complete submergence, seedlings of O. grandiglumis accessions displayed reduced shoot growth and resumed normal growth after desubmergence, similar to the response of submergence-tolerant varieties of O. sativa. Neither SUB1A nor the SK genes were detected in the O. grandiglumis accessions. These results indicate that the O. grandiglumis accessions are capable of adapting successfully to flooding by activating two contrasting mechanisms as the situation demands and that each mechanism of adaptation to flooding is not mediated by SUB1A or the SK genes.

  13. Reactive oxygen species promote heat shock protein 90-mediated HBV capsid assembly

    International Nuclear Information System (INIS)

    Kim, Yoon Sik; Seo, Hyun Wook; Jung, Guhung

    2015-01-01

    Hepatitis B virus (HBV) infection induces reactive oxygen species (ROS) production and has been associated with the development of hepatocellular carcinoma (HCC). ROS are also an important factor in HCC because the accumulated ROS leads to abnormal cell proliferation and chromosome mutation. In oxidative stress, heat shock protein 90 (Hsp90) and glutathione (GSH) function as part of the defense mechanism. Hsp90 prevents cellular component from oxidative stress, and GSH acts as antioxidants scavenging ROS in the cell. However, it is not known whether molecules regulated by oxidative stress are involved in HBV capsid assembly. Based on the previous study that Hsp90 facilitates HBV capsid assembly, which is an important step for the packing of viral particles, here, we show that ROS enrich Hsp90-driven HBV capsid formation. In cell-free system, HBV capsid assembly was facilitated by ROS with Hsp90, whereas it was decreased without Hsp90. In addition, GSH inhibited the function of Hsp90 to decrease HBV capsid assembly. Consistent with the result of cell-free system, ROS and buthionine sulfoximine (BS), an inhibitor of GSH synthesis, increased HBV capsid formation in HepG2.2.15 cells. Thus, our study uncovers the interplay between ROS and Hsp90 during HBV capsid assembly. - Highlights: • We examined H 2 O 2 and GSH modulate HBV capsid assembly. • H 2 O 2 facilitates HBV capsid assembly in the presence of Hsp90. • GSH inhibits function of Hsp90 in facilitating HBV capsid assembly. • H 2 O 2 and GSH induce conformation change of Hsp90

  14. Reactive oxygen species promote heat shock protein 90-mediated HBV capsid assembly

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yoon Sik, E-mail: yumshak@naver.com; Seo, Hyun Wook, E-mail: suruk@naver.com; Jung, Guhung, E-mail: drjung@snu.ac.kr

    2015-02-13

    Hepatitis B virus (HBV) infection induces reactive oxygen species (ROS) production and has been associated with the development of hepatocellular carcinoma (HCC). ROS are also an important factor in HCC because the accumulated ROS leads to abnormal cell proliferation and chromosome mutation. In oxidative stress, heat shock protein 90 (Hsp90) and glutathione (GSH) function as part of the defense mechanism. Hsp90 prevents cellular component from oxidative stress, and GSH acts as antioxidants scavenging ROS in the cell. However, it is not known whether molecules regulated by oxidative stress are involved in HBV capsid assembly. Based on the previous study that Hsp90 facilitates HBV capsid assembly, which is an important step for the packing of viral particles, here, we show that ROS enrich Hsp90-driven HBV capsid formation. In cell-free system, HBV capsid assembly was facilitated by ROS with Hsp90, whereas it was decreased without Hsp90. In addition, GSH inhibited the function of Hsp90 to decrease HBV capsid assembly. Consistent with the result of cell-free system, ROS and buthionine sulfoximine (BS), an inhibitor of GSH synthesis, increased HBV capsid formation in HepG2.2.15 cells. Thus, our study uncovers the interplay between ROS and Hsp90 during HBV capsid assembly. - Highlights: • We examined H{sub 2}O{sub 2} and GSH modulate HBV capsid assembly. • H{sub 2}O{sub 2} facilitates HBV capsid assembly in the presence of Hsp90. • GSH inhibits function of Hsp90 in facilitating HBV capsid assembly. • H{sub 2}O{sub 2} and GSH induce conformation change of Hsp90.

  15. Silicon Promotes Exodermal Casparian Band Formation in Si-Accumulating and Si-Excluding Species by Forming Phenol Complexes.

    Directory of Open Access Journals (Sweden)

    Alexander T Fleck

    Full Text Available We studied the effect of Silicon (Si on Casparian band (CB development, chemical composition of the exodermal CB and Si deposition across the root in the Si accumulators rice and maize and the Si non-accumulator onion. Plants were cultivated in nutrient solution with and without Si supply. The CB development was determined in stained root cross-sections. The outer part of the roots containing the exodermis was isolated after enzymatic treatment. The exodermal suberin was transesterified with MeOH/BF3 and the chemical composition was measured using gas chromatography-mass spectroscopy (GC-MS and flame ionization detector (GC-FID. Laser ablation-inductively coupled plasma-mass spectroscopy (LA-ICP-MS was used to determine the Si deposition across root cross sections. Si promoted CB formation in the roots of Si-accumulator and Si non-accumulator species. The exodermal suberin was decreased in rice and maize due to decreased amounts of aromatic suberin fractions. Si did not affect the concentration of lignin and lignin-like polymers in the outer part of rice, maize and onion roots. The highest Si depositions were found in the tissues containing CB. These data along with literature were used to suggest a mechanism how Si promotes the CB development by forming complexes with phenols.

  16. Dihydro-β-agarofuran sesquiterpenes from celastraceae species as anti-tumour-promoting agents: Structure-activity relationship.

    Science.gov (United States)

    Núñez, Marvin J; Jiménez, Ignacio A; Mendoza, Cristina R; Chavez-Sifontes, Marvin; Martinez, Morena L; Ichiishi, Eiichiro; Tokuda, Ryo; Tokuda, Harukuni; Bazzocchi, Isabel L

    2016-03-23

    Inhibition of tumour promotion in multistage chemical carcinogenesis is considered a promising strategy for cancer chemoprevention. In an ongoing investigation of bioactive secondary metabolites from Celastraceae species, five new dihydro-β-agarofuran sesquiterpenes (1-5), named Chiapens A-E, and seventeen known ones, were isolated from Maytenus chiapensis. Their structures were elucidated by extensive NMR spectroscopic and mass spectrometric techniques, and their absolute configurations were determined by circular dichroism studies, chemical correlations and biogenic means. The isolated compounds, along with twenty known sesquiterpenes, previously isolated from Zinowiewia costaricensis, have been tested for their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorpol-13-acetate (TPA). Thirty three compounds from this series showed stronger effects than that of β-carotene, the reference inhibitor. The structure-activity relationship (SAR) analysis revealed that the type of substituent, in particular at the C-1 position of the sesquiterpene scaffold, was able to modulate the anti-tumour promoting activity. Compounds 3, 6, and 33 showed significant effects in an in vivo two-stage mouse-skin carcinogenesis model. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  17. Gelsolin-Cu/ZnSOD interaction alters intracellular reactive oxygen species levels to promote cancer cell invasion

    KAUST Repository

    Tochhawng, Lalchhandami

    2016-07-07

    The actin-binding protein, gelsolin, is a well known regulator of cancer cell invasion. However, the mechanisms by which gelsolin promotes invasion are not well established. As reactive oxygen species (ROS) have been shown to promote cancer cell invasion, we investigated on the hypothesis that gelsolin-induced changes in ROS levels may mediate the invasive capacity of colon cancer cells. Herein, we show that increased gelsolin enhances the invasive capacity of colon cancer cells, and this is mediated via gelsolin\\'s effects in elevating intracellular superoxide (O2 .-) levels. We also provide evidence for a novel physical interaction between gelsolin and Cu/ZnSOD, that inhibits the enzymatic activity of Cu/ZnSOD, thereby resulting in a sustained elevation of intracellular O2 .-. Using microarray data of human colorectal cancer tissues from Gene Omnibus, we found that gelsolin gene expression positively correlates with urokinase plasminogen activator (uPA), an important matrix-degrading protease invovled in cancer invasion. Consistent with the in vivo evidence, we show that increased levels of O2 .- induced by gelsolin overexpression triggers the secretion of uPA. We further observed reduction in invasion and intracellular O2 .- levels in colon cancer cells, as a consequence of gelsolin knockdown using two different siRNAs. In these cells, concurrent repression of Cu/ ZnSOD restored intracellular O2 .- levels and rescued invasive capacity. Our study therefore identified gelsolin as a novel regulator of intracellular O2 .- in cancer cells via interacting with Cu/ZnSOD and inhibiting its enzymatic activity. Taken together, these findings provide insight into a novel function of gelsolin in promoting tumor invasion by directly impacting the cellular redox milieu.

  18. Plant functional coexistence and influence on the eco-hydrologic response of semiarid hillslopes

    Science.gov (United States)

    Soltanjalili, Mohammadjafar; Saco, Patricia M.; Willgoose, Garry

    2016-04-01

    Through its influence on rainfall-runoff and erosion-deposition processes, vegetation remarkably regulates different aspects of landscape processes. Here, the influence of different plant functional dynamics on the coexistence of different species in arid and semi-arid regions with banded vegetation patterns is investigated. Simulations capture the coevolution and coexistence of two different species interacting with hydrology in hillslopes with gentle slopes. The dynamic vegetation model simulates the dynamics of overland runoff, soil moisture, facilitation mechanisms (evaporation reduction through shading and enhanced infiltration by vegetation), local and non-local seed dispersal, competition through water uptake and changes in the biomass of the two species. Here for simplicity the two species are assumed to use water from the same soil depth. Results of the coexistence of the two species capture differences in facilitation-competition interactions caused by specific types of vegetation with varying hydrologic traits. The results illustrate that the dominance of facilitation or competition feedbacks which determine either the coexistence of the two species or survival of only one of them strongly depends on the characteristics and hydrologic traits of the coexisting species and the severity of water stresses. We therefore argue that our results should stimulate further research into the role of interspecific and intraspecific feedbacks between different plant species and specifically the influence of the resulting vegetation community on landform evolution processes.

  19. Coexistence via resource partitioning fails to generate an increase in community function.

    Directory of Open Access Journals (Sweden)

    John P DeLong

    Full Text Available Classic ecological theory suggests that resource partitioning facilitates the coexistence of species by reducing inter-specific competition. A byproduct of this process is an increase in overall community function, because a greater spectrum of resources can be used. In contrast, coexistence facilitated by neutral mechanisms is not expected to increase function. We studied coexistence in laboratory microcosms of the bactivorous ciliates Paramecium aurelia and Colpidium striatum to understand the relationship between function and coexistence mechanism. We quantified population and community-level function (biomass and oxygen consumption, competitive interactions, and resource partitioning. The two ciliates partitioned their bacterial resource along a size axis, with the larger ciliate consuming larger bacteria than the smaller ciliate. Despite this, there was no gain in function at the community level for either biomass or oxygen consumption, and competitive effects were symmetrical within and between species. Because other potential coexistence mechanisms can be ruled out, it is likely that inter-specific interference competition diminished the expected gain in function generated by resource partitioning, leading to a system that appeared competitively neutral even when structured by niche partitioning. We also analyzed several previous studies where two species of protists coexisted and found that the two-species communities showed a broad range of biomass levels relative to the single-species states.

  20. Biodiversity in the cyclic competition system of three species according to the emergence of mutant species

    Science.gov (United States)

    Park, Junpyo

    2018-05-01

    Understanding mechanisms which promote or hinder existing ecosystems are important issues in ecological sciences. In addition to fundamental interactions such as competition and migration among native species, existing ecosystems can be easily disturbed by external factors, and the emergence of new species may be an example in such cases. The new species which does not exist in a current ecosystem can be regarded as either alien species entered from outside or mutant species born by mutation in existing normal species. Recently, as existing ecosystems are getting influenced by various physical/chemical external factors, mutation due to anthropogenic and environmental factors can occur more frequently and is thus attracting much attention for the maintenance of ecosystems. In this paper, we consider emergences of mutant species among self-competing three species in the cyclic dominance. By defining mutation as the birth of mutant species, we investigate how mutant species can affect biodiversity in the existing ecosystem. Through microscopic and macroscopic approaches, we have found that the society of existing normal species can be disturbed by mutant species either the society is maintained accompanying with the coexistence of all species or jeopardized by occupying of mutant species. Due to the birth of mutant species, the existing society may be more complex by constituting two different groups of normal and mutant species, and our results can be contributed to analyze complex ecosystems of many species. We hope our findings may propose a new insight on mutation in cyclic competition systems of many species.

  1. Opposing effects of floral visitors and soil conditions on the determinants of competitive outcomes maintain species diversity in heterogeneous landscapes.

    Science.gov (United States)

    Lanuza, Jose B; Bartomeus, Ignasi; Godoy, Oscar

    2018-06-01

    Theory argues that both soil conditions and aboveground trophic interactions have equivalent potential to limit or promote plant diversity. However, it remains unexplored how they jointly modify the niche differences stabilising species coexistence and the average fitness differences driving competitive dominance. We conducted a field study in Mediterranean annual grasslands to parameterise population models of six competing plant species. Spatially explicit floral visitor assemblages and soil salinity variation were characterised for each species. Both floral visitors and soil salinity modified species population dynamics via direct changes in seed production and indirect changes in competitive responses. Although the magnitude and sign of these changes were species-specific, floral visitors promoted coexistence at neighbourhood scales, while soil salinity did so over larger scales by changing the superior competitors' identity. Our results show how below and aboveground interactions maintain diversity in heterogeneous landscapes through their opposing effects on the determinants of competitive outcomes. © 2018 John Wiley & Sons Ltd/CNRS.

  2. An unusual coexistence of Addison's disease and ...

    African Journals Online (AJOL)

    2013-07-17

    Jul 17, 2013 ... Case Study: An unusual coexistence of Addison's disease and phaeochromocytoma. 164 ... strongly positive. ... Department of Endocrinology and Metabolism, Ondokuz Mayis University Medical School, Samsun, Turkey.

  3. Phase Coexistence in Insect Swarms

    Science.gov (United States)

    Sinhuber, Michael; Ouellette, Nicholas T.

    2017-10-01

    Animal aggregations are visually striking, and as such are popular examples of collective behavior in the natural world. Quantitatively demonstrating the collective nature of such groups, however, remains surprisingly difficult. Inspired by thermodynamics, we applied topological data analysis to laboratory insect swarms and found evidence for emergent, material-like states. We show that the swarms consist of a core "condensed" phase surrounded by a dilute "vapor" phase. These two phases coexist in equilibrium, and maintain their distinct macroscopic properties even though individual insects pass freely between them. We further define a pressure and chemical potential to describe these phases, extending theories of active matter to aggregations of macroscopic animals and laying the groundwork for a thermodynamic description of collective animal groups.

  4. Long-term competitive dynamics of two cryptic rotifer species: diapause and fluctuating conditions.

    Directory of Open Access Journals (Sweden)

    Carmen Gabaldón

    Full Text Available Life-history traits may have an important role in promoting species coexistence. However, the complexity of certain life cycles makes it difficult to draw conclusions about the conditions for coexistence or exclusion based on the study of short-term competitive dynamics. Brachionus plicatilis and B. manjavacasare two cryptic rotifer species co-occurring in many lakes on the Iberian Peninsula. They have a complex life cycle in which cyclical parthenogenesis occurs with diapausing stages being the result of sexual reproduction. B. plicatilis and B. manjavacasare identical in morphology and size, their biotic niches are broadly overlapping, and they have similar competitive abilities. However, the species differ in life-history traits involving sexual reproduction and diapause, and respond differently to salinity and temperature. As in the case of certain other species that are extremely similar in morphology, a fluctuating environment are considered to be important for their coexistence. We studied the long-term competitive dynamics of B. plicatilis and B. manjavacas under different salinity regimes (constant and fluctuating. Moreover, we focused on the dynamics of the diapausing egg bank to explore how the outcome of the entire life cycle of these rotifers can work to mediate stable coexistence. We demonstrated that these species do not coexist under constant-salinity environment, as the outcome of competition is affected by the level of salinity-at low salinity, B. plicatilis excluded B. manjavacas, and the opposite outcome occurred at high salinity. Competitive dynamics under fluctuating salinity showed that the dominance of one species over the other also tended to fluctuate. The duration of co-occurrence of these species was favoured by salinity fluctuation and perhaps by the existence of a diapausing egg bank. Stable coexistence was not found in our system, which suggests that other factors or other salinity fluctuation patterns might act as

  5. Long-term competitive dynamics of two cryptic rotifer species: diapause and fluctuating conditions.

    Science.gov (United States)

    Gabaldón, Carmen; Carmona, María José; Montero-Pau, Javier; Serra, Manuel

    2015-01-01

    Life-history traits may have an important role in promoting species coexistence. However, the complexity of certain life cycles makes it difficult to draw conclusions about the conditions for coexistence or exclusion based on the study of short-term competitive dynamics. Brachionus plicatilis and B. manjavacasare two cryptic rotifer species co-occurring in many lakes on the Iberian Peninsula. They have a complex life cycle in which cyclical parthenogenesis occurs with diapausing stages being the result of sexual reproduction. B. plicatilis and B. manjavacasare identical in morphology and size, their biotic niches are broadly overlapping, and they have similar competitive abilities. However, the species differ in life-history traits involving sexual reproduction and diapause, and respond differently to salinity and temperature. As in the case of certain other species that are extremely similar in morphology, a fluctuating environment are considered to be important for their coexistence. We studied the long-term competitive dynamics of B. plicatilis and B. manjavacas under different salinity regimes (constant and fluctuating). Moreover, we focused on the dynamics of the diapausing egg bank to explore how the outcome of the entire life cycle of these rotifers can work to mediate stable coexistence. We demonstrated that these species do not coexist under constant-salinity environment, as the outcome of competition is affected by the level of salinity-at low salinity, B. plicatilis excluded B. manjavacas, and the opposite outcome occurred at high salinity. Competitive dynamics under fluctuating salinity showed that the dominance of one species over the other also tended to fluctuate. The duration of co-occurrence of these species was favoured by salinity fluctuation and perhaps by the existence of a diapausing egg bank. Stable coexistence was not found in our system, which suggests that other factors or other salinity fluctuation patterns might act as stabilizing

  6. General two-species interacting Lotka-Volterra system: Population dynamics and wave propagation

    Science.gov (United States)

    Zhu, Haoqi; Wang, Mao-Xiang; Lai, Pik-Yin

    2018-05-01

    The population dynamics of two interacting species modeled by the Lotka-Volterra (LV) model with general parameters that can promote or suppress the other species is studied. It is found that the properties of the two species' isoclines determine the interaction of species, leading to six regimes in the phase diagram of interspecies interaction; i.e., there are six different interspecific relationships described by the LV model. Four regimes allow for nontrivial species coexistence, among which it is found that three of them are stable, namely, weak competition, mutualism, and predator-prey scenarios can lead to win-win coexistence situations. The Lyapunov function for general nontrivial two-species coexistence is also constructed. Furthermore, in the presence of spatial diffusion of the species, the dynamics can lead to steady wavefront propagation and can alter the population map. Propagating wavefront solutions in one dimension are investigated analytically and by numerical solutions. The steady wavefront speeds are obtained analytically via nonlinear dynamics analysis and verified by numerical solutions. In addition to the inter- and intraspecific interaction parameters, the intrinsic speed parameters of each species play a decisive role in species populations and wave properties. In some regimes, both species can copropagate with the same wave speeds in a finite range of parameters. Our results are further discussed in the light of possible biological relevance and ecological implications.

  7. Density-dependency and plant-soil feedback: former plant abundance influences competitive interactions between two grassland plant species through plant-soil feedbacks

    NARCIS (Netherlands)

    Xue, W.; Bezemer, T.M.; Berendse, Frank

    2018-01-01

    Backgrounds and aims Negative plant-soil feedbacks (PSFs) are thought to promote species coexistence, but most evidence is derived from theoretical models and data from plant monoculture experiments. Methods We grew Anthoxanthum odoratum and Centaurea jacea in field plots in monocultures and in

  8. Aggression and coexistence in female caribou

    Science.gov (United States)

    Weckerly, Floyd W.; Ricca, Mark A.

    2014-01-01

    Female caribou (Rangifer tarandus) are highly gregarious, yet there has been little study of the behavioral mechanisms that foster coexistence. Quantifying patterns of aggression between male and female, particularly in the only cervid taxa where both sexes grow antlers, should provide insight into these mechanisms. We asked if patterns of aggression by male and female caribou followed the pattern typically noted in other polygynous cervids, in which males display higher frequencies and intensity of aggression. From June to August in 2011 and 2012, we measured the frequency and intensity of aggression across a range of group sizes through focal animal sampling of 170 caribou (64 males and 106 females) on Adak Island in the Aleutian Archipelago, Alaska. Males in same-sex and mixed-sex groups and females in mixed-sex groups had higher frequencies of aggression than females in same-sex groups. Group size did not influence frequency of aggression. Males displayed more intense aggression than females. Frequent aggression in mixed-sex groups probably reflects lower tolerance of males for animals in close proximity. Female caribou were less aggressive and more gregarious than males, as in other polygynous cervid species.

  9. Crecimiento y supervivencia de plántulas de cinco especies de Acacia (Fabaceae, que coexisten en bosques secos neotropicales de Argentina, en distintas condiciones de disponibilidad de luz y agua Seedlings growth and survival of five Acacia (Fabaceae species that coexists in neotropical semiarid forests of Argentina, under different light and water availability conditions

    Directory of Open Access Journals (Sweden)

    Paula Venier

    2013-06-01

    Full Text Available El establecimiento de la plántula es una de las etapas más riesgosas para las plantas, especialmente en zonas áridas y semiáridas donde la sequía y alta radiación solar influyen sobre su emergencia, desarrollo y supervivencia. Se evaluó en invernadero la supervivencia y variables de crecimiento en plántulas sometidas a estrés hídrico y a distintas condiciones de luz, en cinco especies de Acacia (A. aroma, A. caven, A. atramentaria, A. gilliesii y A. praecox que coexisten en los bosques xerófilos de Córdoba, Argentina. Aunque se encontraron diferencias entre las especies (F=5.66, p=0.001, todas tuvieron altos porcentajes de supervivencia en las distintas condiciones de luz y agua, sugiriendo que serían tolerantes al estrés hídrico y podrían establecerse bajo luz o sombra. Si bien todas las especies mejoraron el crecimiento con luz y sin estrés hídrico, A. aroma, A. caven y A. atramentaria mostraron una tendencia hacia un mayor crecimiento en la mayoría de las variables consideradas (F=41.9, pSeedling establishment is one of the most risky stages of plants, especially in arid and semiarid regions, where low water availability and high solar radiation influence its emergence, development and survival. In seasonally dry xerophytic forests occurring in North-Western Córdoba, central Argentina, five neotropical species of Acacia co-exist: A. aroma, A. caven, A. atramentaria, A. gilliesii and A. praecox. With the aim to evaluate growth variables and survival of these five species seedlings, in response to water stress and different light availability conditions, a greenhouse experiment was undertaken from March to June of 2010. Although small differences were found between species (F=5.66, p=0.001, all of them showed high percentages of seedling survival in response to different light and water treatments, suggesting that seedlings would be tolerant to water stress and could be established both in light and shade. On the other hand

  10. Shape coexistence in N = 28 isotones

    International Nuclear Information System (INIS)

    Saxena, G.; Kaushik, M.; Kumawat, M.; Jain, S.K.

    2016-01-01

    Shape coexistence is one of the important nuclear phenomenon which appears throughout the periodic chart from light mass nuclei to superheavy nuclei. The evolution of ground-state shapes in an isotopic or isotonic chain is governed by changes of the shell structure of single-nucleon orbitals. In recent past, evolution of shell structure guiding shape coexistence, has been observed in the N = 20 and N = 28 isotones around proton drip line. In this paper we have investigated shape coexistence phenomenon for N = 28 isotones in the vicinity of proton drip line using Relativistic Mean Field plus BCS approach

  11. Shape coexistence in N = 40 isotones

    International Nuclear Information System (INIS)

    Saxena, G.; Kumawat, M.; Kaushik, M.; Jain, S.K.; Aggarwal, Mamta

    2017-01-01

    Recently, shape coexistence in 72 Ge is investigated using projectile multistep Coulomb excitation with GRETINA and CHICO-2 and shape coexistence in the Ge and Se isotopes are studied within the interacting boson model (IBM) with the microscopic input from the self-consistent meanfield calculation based on the Gogny-D1M energy density functional. We investigated the phenomenon of shape coexistence in N = 40 isotones using Relativistic Mean-Field (RMF) plus BCS approach with TMA parameter and Nilson Strutinsky (NS) method that includes triaxial shapes also

  12. The role of tin-promoted Pd/MWNTs via the management of carbonaceous species in selective hydrogenation of high concentration acetylene

    International Nuclear Information System (INIS)

    Esmaeili, Elaheh; Mortazavi, Yadollah; Khodadadi, Abbas Ali; Rashidi, Ali Morad; Rashidzadeh, Mehdi

    2012-01-01

    Highlights: ► Synthesis of highly active tin-promoted catalysts by polyol method for selective hydrogenation of high concentration of acetylene. ► A positive change in the catalytic activities of tin-promoted catalysts results from distinct geometric and electronic effects. ► Change in the coverage of acetylenic overlayers for different temperature regions corresponds to the change of the number of isolated adsorption sites. ► The isolated adsorption sites are responsible for the enhancement of selectivity to ethylene with increased temperatures, via the management of the carbonaceous species over the catalyst surface. - Abstract: In the present study, Pd/MWNTs are synthesized using polyol process and modified by tin as a promoter for selective hydrogenation of high concentrated acetylene feedstock. Polyol method results in highly dispersed nanoparticles with a depletion of particle size for tin-promoted Pd catalysts as characterized by TEM. Tin promoter plays a considerable role in hydrogenation of pure acetylene stream. This is attributed to formation of Pd 2 Sn structural phase, confirmed by XRD and TPR techniques, composed mainly of intermetallic species. Catalytic behavior of tin-promoted Pd catalysts is affected by geometric and electronic factors which are more pronounced in the case of Sn/Pd = 0.25. A discontinuity in Arrhenius plots for the Sn-promoted catalysts is appeared, which seems to be due to a kinetic factor as a result of change in acetylene coverage on Pd metallic ensembles at low and high temperature ranges. Higher selectivity of the catalysts to ethylene is attributed to the presence of more isolated adsorption sites on the catalyst surface originated from both intermetallic compounds confirmed by XPS and the ones formed via the carbonaceous species upon the acetylene hydrogenation reaction.

  13. Similarity law for Widom lines and coexistence lines.

    Science.gov (United States)

    Banuti, D T; Raju, M; Ihme, M

    2017-05-01

    The coexistence line of a fluid separates liquid and gaseous states at subcritical pressures, ending at the critical point. Only recently, it became clear that the supercritical state space can likewise be divided into regions with liquidlike and gaslike properties, separated by an extension to the coexistence line. This crossover line is commonly referred to as the Widom line, and is characterized by large changes in density or enthalpy, manifesting as maxima in the thermodynamic response functions. Thus, a reliable representation of the coexistence line and the Widom line is important for sub- and supercritical applications that depend on an accurate prediction of fluid properties. While it is known for subcritical pressures that nondimensionalization with the respective species critical pressures p_{cr} and temperatures T_{cr} only collapses coexistence line data for simple fluids, this approach is used for Widom lines of all fluids. However, we show here that the Widom line does not adhere to the corresponding states principle, but instead to the extended corresponding states principle. We resolve this problem in two steps. First, we propose a Widom line functional based on the Clapeyron equation and derive an analytical, species specific expression for the only parameter from the Soave-Redlich-Kwong equation of state. This parameter is a function of the acentric factor ω and compares well with experimental data. Second, we introduce the scaled reduced pressure p_{r}^{*} to replace the previously used reduced pressure p_{r}=p/p_{cr}. We show that p_{r}^{*} is a function of the acentric factor only and can thus be readily determined from fluid property tables. It collapses both subcritical coexistence line and supercritical Widom line data over a wide range of species with acentric factors ranging from -0.38 (helium) to 0.34 (water), including alkanes up to n-hexane. By using p_{r}^{*}, the extended corresponding states principle can be applied within

  14. The Ecohydrologic Role of Coexistence and Competition in Semiarid Hillslopes

    Science.gov (United States)

    Soltanjalili, M. J.; Saco, P. M.; Willgoose, G. R.

    2015-12-01

    Through its influence on runoff and erosion-deposition processes, vegetation remarkably regulates different aspects of landscape dynamics. Here, the influence of different plant functional traits on the coexistence of different species in arid and semi-arid regions with patchy vegetation is investigated using an ecohydrology model. The model simulates coevolving changes in biomass patterns for two species, as well as overland flow and soil moisture dynamics. Vegetation patterns emerge as a result of facilitation (shading and infiltration) and competition mechanisms as well as varying seed dispersal strategies. The results show that the survival of only one species or the coexistence of both species not only strongly depends on environmental stresses, but also on differences in hillslope micro and macro topography. These vegetation patterns have very different hydrologic signatures and the potential to trigger remarkably different geomorphic responses. Based on these results we establish new hypothesis that will be used to further investigate the role of plant interspecific and intraspecific feedbacks on landscape coevolution processes.

  15. Landscapes of facilitation: how self-organized patchiness of aquatic macrophytes promotes diversity in streams.

    Science.gov (United States)

    Cornacchia, Loreta; van de Koppel, Johan; van der Wal, Daphne; Wharton, Geraldene; Puijalon, Sara; Bouma, Tjeerd J

    2018-04-01

    Spatial heterogeneity plays a crucial role in the coexistence of species. Despite recognition of the importance of self-organization in creating environmental heterogeneity in otherwise uniform landscapes, the effects of such self-organized pattern formation in promoting coexistence through facilitation are still unknown. In this study, we investigated the effects of pattern formation on species interactions and community spatial structure in ecosystems with limited underlying environmental heterogeneity, using self-organized patchiness of the aquatic macrophyte Callitriche platycarpa in streams as a model system. Our theoretical model predicted that pattern formation in aquatic vegetation - due to feedback interactions between plant growth, water flow and sedimentation processes - could promote species coexistence, by creating heterogeneous flow conditions inside and around the plant patches. The spatial plant patterns predicted by our model agreed with field observations at the reach scale in naturally vegetated rivers, where we found a significant spatial aggregation of two macrophyte species around C. platycarpa. Field transplantation experiments showed that C. platycarpa had a positive effect on the growth of both beneficiary species, and the intensity of this facilitative effect was correlated with the heterogeneous hydrodynamic conditions created within and around C. platycarpa patches. Our results emphasize the importance of self-organized patchiness in promoting species coexistence by creating a landscape of facilitation, where new niches and facilitative effects arise in different locations. Understanding the interplay between competition and facilitation is therefore essential for successful management of biodiversity in many ecosystems. © 2018 The Authors Ecology published by Wiley Periodicals, Inc. on behalf of Ecological Society of America.

  16. Variation in moisture duration as a driver of coexistence by the storage effect in desert annual plants.

    Science.gov (United States)

    Holt, Galen; Chesson, Peter

    2014-03-01

    Temporal environmental variation is a leading hypothesis for the coexistence of desert annual plants. Environmental variation is hypothesized to cause species-specific patterns of variation in germination, which then generates the storage effect coexistence mechanism. However, it has never been shown how sufficient species differences in germination patterns for multispecies coexistence can arise from a shared fluctuating environment. Here we show that nonlinear germination responses to a single fluctuating physical environmental factor can lead to sufficient differences between species in germination pattern for the storage effect to yield coexistence of multiple species. We derive these nonlinear germination responses from experimental data on the effects of varying soil moisture duration. Although these nonlinearities lead to strong species asymmetries in germination patterns, the relative nonlinearity coexistence mechanism is minor compared with the storage effect. However, these asymmetries mean that the storage effect can be negative for some species, which then only persist in the face of interspecific competition through average fitness advantages. This work shows how a low dimensional physical environment can nevertheless stabilize multispecies coexistence when the species have different nonlinear responses to common conditions, as supported by our experimental data. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. Biodiversity and the Lotka-Volterra theory of species interactions: open systems and the distribution of logarithmic densities.

    Science.gov (United States)

    Wilson, William G; Lundberg, Per

    2004-09-22

    Theoretical interest in the distributions of species abundances observed in ecological communities has focused recently on the results of models that assume all species are identical in their interactions with one another, and rely upon immigration and speciation to promote coexistence. Here we examine a one-trophic level system with generalized species interactions, including species-specific intraspecific and interspecific interaction strengths, and density-independent immigration from a regional species pool. Comparisons between results from numerical integrations and an approximate analytic calculation for random communities demonstrate good agreement, and both approaches yield abundance distributions of nearly arbitrary shape, including bimodality for intermediate immigration rates.

  18. Coexistence and sport: the Israeli case

    OpenAIRE

    Yair Galily; Michael Leitner; Pini Shimon

    2013-01-01

    Utilizing sports and other recreational activities to foster peaceful relations and coexistence is an idea that has gained popularity in recent years, particularly in Israel. The aim of the current research is to fill a gap in the research literature on the subject of coexistence programming. The Mifalot organization conducts a program called “Get to Know Your Neighbor” in which Palestinian, Jordanian, and Israeli youth play soccer together. The program, based mainly on the participants’ love...

  19. A Necessary Condition for Coexistence of Autocatalytic Replicators in a Prebiotic Environment

    Science.gov (United States)

    Hernandez, Andres F.; Grover, Martha A.

    2013-01-01

    A necessary, but not sufficient, mathematical condition for the coexistence of short replicating species is presented here. The mathematical condition is obtained for a prebiotic environment, simulated as a fed-batch reactor, which combines monomer recycling, variable reaction order and a fixed monomer inlet flow with two replicator types and two monomer types. An extensive exploration of the parameter space in the model validates the robustness and efficiency of the mathematical condition, with nearly 1.7% of parameter sets meeting the condition and half of those exhibiting sustained coexistence. The results show that it is possible to generate a condition of coexistence, where two replicators sustain a linear growth simultaneously for a wide variety of chemistries, under an appropriate environment. The presence of multiple monomer types is critical to sustaining the coexistence of multiple replicator types. PMID:25369813

  20. A phase-transition induced by the struggle for life in a competitive coexistence model in ecology

    International Nuclear Information System (INIS)

    Wio, H.S.; Kuperman, M.N.

    1994-07-01

    We have studied a spatially homogeneous model of an ecological system consisting of two species: a strong and a weak one, competing for a single food resource. The inclusion of a term corresponding to intraspecies competition, in particular for the strong species, shows that, it a certain threshold value is overcome, the classical result on extinction and coexistence of Lotka-Volterra type equations can drastically change yielding a kind of phase-transition to a coexistence phase. (author). 18 refs, 2 figs

  1. Environmental variability facilitates coexistence within an alcid community at sea

    Science.gov (United States)

    Haney, J. Christopher; Schauer, Amy E.S.

    1994-01-01

    We examined coexistence at sea among 7 taxa of diving, wing-propelled seabirds (Alcidae) in the genera Aethia, Uria, Cepphus, and Fratercula. Species abundances were measured simultaneously with a suite of environmental factors in the northern Bering Sea, Alaska, USA; data from 260 adjacent and non-adjacent sites occupied by alcids foraging offshore near breeding colonies were then subjected to principal component analysis (PCA). We used PCA to group redundant environmental descriptors, to identify orthogonal axes for constructing a multi-dimensional niche, and to differentiate species associations within niche dimensions from species associations among niche dimensions. Decomposition of the correlation matrix for 22 environmental and 7 taxonomic variables with PCA gave 14 components (10 environmental and 4 species interactions) that retained 90% of the original available variance. Alcid abundances (all species) were most strongly correlated with axes representing tidal stage, a time-area interaction (due to sampling layout), water masses, and a temporal or intra-seasonal trend partially associated with weather changes. Axes representing tidal stage, 2 gradients in macro-habitat (Anadyr and Bering Shelf Water masses), the micro-habitat of the sea surface, and an air-sea interaction were most important for detecting differences among species within niche dimensions. Contrary to assumptions of competition, none of 4 compound variables describing primarily species-interactions gave strong evidence for negative associations between alcid taxa sharing similar body sizes and feeding requirements. This exploratory analysis supports the view that alcids may segregate along environmental gradients at sea. But in this community, segregation was unrelated to foraging distance from colonies, in part because foraging 'substrate' was highly variable in structure, location, and area1 extent. We contend that coexistence within this seabird group is facilitated via expanded niche

  2. Coexistence of reef organisms in the Abrolhos Archipelago, Brazil

    Directory of Open Access Journals (Sweden)

    Monica M Lins de Barros

    2000-12-01

    Full Text Available The first study on coexistence of reef benthic organisms in Brazilian coral reefs was done in three localities of the Abrolhos Archipelago. Organisms were recorded in concentric circle samples (10 and 20 cm in diameter randomly laid on transects. Type and frequency of "coexistence events" between pairs of organisms were determined. Most frequent organisms (massive and branched coralline algae, Favia gravida, and Agaricia agaricites also had many significant positive coexistence events. These results might be related to the abundances of these organisms. The most frequent coral (Siderastrea stellata, however, exhibited only a few significant coexistence events (9% of 32 tests. Since the great majority of events were positive, and since there was high variation in the species/groups involved in significant events in different localities, benthic communities of Abrolhos Archipelago may well be structured primarily by abiotic rather than biotic factors.Se hizo el primer estudio de coexistencia de organismos bénticos de arrecifes brasileños en tres localidades del Archipiélago de Abrolhos, registrando la presencia de organismos en círculos de 10 y 20 cm de diametro, distribuidos al azar en transectos. La mayoría de los organismo frecuentes (algas coralinas macizas y ramificadas, Favia gravida y Agaricia agaricites mostraron la más alta "coexistencia positiva", tal vez por su abundancia. El coral más frecuente (Siderastrea stellata, sin embargo, mostró apenas algunos eventos de coexistencia significativos (9% de 32 ensayos. Debido a que la mayor parte de los eventos fue positiva, y considerando que existe una alta variabilidad en las interacciones significativas en diferentes localidades, las comunidades bénticas del Archipiélago de Abrolhos pueden haber sido estructuradas principalmente por factores abióticos, mas que por factores bióticos.

  3. Coexistence facilitates interspecific biofilm formation in complex microbial communities

    DEFF Research Database (Denmark)

    Madsen, Jonas Stenløkke; Røder, Henriette Lyng; Russel, Jakob

    2016-01-01

    Social interactions in which bacteria respond to one another by modifying their phenotype are central determinants of microbial communities. It is known that interspecific interactions influence the biofilm phenotype of bacteria; a phenotype that is central to the fitness of bacteria. However......, the underlying role of fundamental ecological factors, specifically coexistence and phylogenetic history, in biofilm formation remains unclear. This study examines how social interactions affect biofilm formation in multi-species co-cultures from five diverse environments. We found prevalence of increased...

  4. TrxR2 deficiencies promote chondrogenic differentiation and induce apoptosis of chondrocytes through mitochondrial reactive oxygen species

    International Nuclear Information System (INIS)

    Yan, Jidong; Xu, Jing; Fei, Yao; Jiang, Congshan; Zhu, Wenhua; Han, Yan; Lu, Shemin

    2016-01-01

    Thioredoxin reductase 2 (TrxR2) is a selenium (Se) containing protein. Se deficiency is associated with an endemic osteoarthropathy characterized by impaired cartilage formation. It is unclear whether TrxR2 have roles in cartilage function. We examined the effects of TrxR2 on chondrogenic ATDC5 cells through shRNA-mediated gene silencing of TrxR2. We demonstrated TrxR2 deficiencies could enhance chondrogenic differentiation and apoptosis of ATDC5 cells. TrxR2 deficiencies increased accumulation of cartilage glycosaminoglycans (GAGs) and mineralization. TrxR2 deficiencies also stimulated expression of extracellular (ECM) gene including Collagen II and Aggrecan. The enhanced chondrogenic properties were further confirmed by activation of Akt signaling which are required for chondrogenesis. In addition, TrxR2 deficiencies promoted chondrocyte proliferation through acceleration of cell cycle progression by increase in both S and G2/M phase cell distribution accompanied with induction of parathyroid hormone-related protein (PTHrP). Moreover, TrxR2 deficiencies induced chondrocyte death via apoptosis and increased cell sensitivity to exogenous oxidative stress. Furthermore, TrxR2 deficiencies induced emission of mitochondrial reactive oxygen species (ROS) without alteration of mitochondrial membrane potential and intracellular ATP content. Finally, treatment of TrxR2 deficiency cells with N-acetylcysteine (NAC) inhibited mitochondrial ROS production and chondrocyte apoptosis. NAC also prevented chondrogenic differentiation of TrxR2 deficiency cells by suppression of ECM gene expression, GAGs accumulation and mineralization, as well as attenuation of Akt signaling. Thus, TrxR2-mediated mitochondrial integrity is indispensable for chondrogenic differentiation of ATDC5 cells. TrxR2 deficiency-induced impaired proliferation and death of chondrocytes may be the pathological mechanism of the osteoarthropathy due to Se deficiency. Notably, this study also uncover the roles of

  5. TrxR2 deficiencies promote chondrogenic differentiation and induce apoptosis of chondrocytes through mitochondrial reactive oxygen species

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Jidong [Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, Shaanxi 710061 (China); Xu, Jing [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, Shaanxi 710061 (China); Fei, Yao [College of Life Sciences, Northwest University, Xi’an, Shaanxi Province 710069 (China); Jiang, Congshan; Zhu, Wenhua; Han, Yan [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, Shaanxi 710061 (China); Lu, Shemin, E-mail: lushemin@xjtu.edu.cn [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, Shaanxi 710061 (China); Key Laboratory of Environment and Genes Related to Diseases, Xi’an Jiaotong University, Ministry of Education of China (China)

    2016-05-15

    Thioredoxin reductase 2 (TrxR2) is a selenium (Se) containing protein. Se deficiency is associated with an endemic osteoarthropathy characterized by impaired cartilage formation. It is unclear whether TrxR2 have roles in cartilage function. We examined the effects of TrxR2 on chondrogenic ATDC5 cells through shRNA-mediated gene silencing of TrxR2. We demonstrated TrxR2 deficiencies could enhance chondrogenic differentiation and apoptosis of ATDC5 cells. TrxR2 deficiencies increased accumulation of cartilage glycosaminoglycans (GAGs) and mineralization. TrxR2 deficiencies also stimulated expression of extracellular (ECM) gene including Collagen II and Aggrecan. The enhanced chondrogenic properties were further confirmed by activation of Akt signaling which are required for chondrogenesis. In addition, TrxR2 deficiencies promoted chondrocyte proliferation through acceleration of cell cycle progression by increase in both S and G2/M phase cell distribution accompanied with induction of parathyroid hormone-related protein (PTHrP). Moreover, TrxR2 deficiencies induced chondrocyte death via apoptosis and increased cell sensitivity to exogenous oxidative stress. Furthermore, TrxR2 deficiencies induced emission of mitochondrial reactive oxygen species (ROS) without alteration of mitochondrial membrane potential and intracellular ATP content. Finally, treatment of TrxR2 deficiency cells with N-acetylcysteine (NAC) inhibited mitochondrial ROS production and chondrocyte apoptosis. NAC also prevented chondrogenic differentiation of TrxR2 deficiency cells by suppression of ECM gene expression, GAGs accumulation and mineralization, as well as attenuation of Akt signaling. Thus, TrxR2-mediated mitochondrial integrity is indispensable for chondrogenic differentiation of ATDC5 cells. TrxR2 deficiency-induced impaired proliferation and death of chondrocytes may be the pathological mechanism of the osteoarthropathy due to Se deficiency. Notably, this study also uncover the roles of

  6. Testing spatial theories of plant coexistence: no consistent differences in intra- and interspecific interaction distances.

    Science.gov (United States)

    Vogt, Deborah R; Murrell, David J; Stoll, Peter

    2010-01-01

    Plants stand still and interact with their immediate neighbors. Theory has shown that the distances over which these interactions occur may have important consequences for population and community dynamics. In particular, if intraspecific competition occurs over longer distances than interspecific competition (heteromyopia), coexistence can be promoted. We examined how intraspecific and interspecific competition scales with neighbor distance in a target-neighbor greenhouse competition experiment. Individuals from co-occurring forbs from calcareous grasslands were grown in isolation and with single conspecific or heterospecific neighbors at distances of 5, 10, or 15 cm (Plantago lanceolata vs. Plantago media and Hieracium pilosella vs. Prunella grandiflora). Neighbor effects were strong and declined with distance. Interaction distances varied greatly within and between species, but we found no evidence for heteromyopia. Instead, neighbor identity effects were mostly explained by relative size differences between target and neighbor. We found a complex interaction between final neighbor size and identity such that neighbor identity may become important only as the neighbor becomes very large compared with the target individual. Our results suggest that species-specific size differences between neighboring individuals determine both the strength of competitive interactions and the distance over which these interactions occur.

  7. Predicting coexistence of plants subject to a tolerance-competition trade-off.

    Science.gov (United States)

    Haegeman, Bart; Sari, Tewfik; Etienne, Rampal S

    2014-06-01

    Ecological trade-offs between species are often invoked to explain species coexistence in ecological communities. However, few mathematical models have been proposed for which coexistence conditions can be characterized explicitly in terms of a trade-off. Here we present a model of a plant community which allows such a characterization. In the model plant species compete for sites where each site has a fixed stress condition. Species differ both in stress tolerance and competitive ability. Stress tolerance is quantified as the fraction of sites with stress conditions low enough to allow establishment. Competitive ability is quantified as the propensity to win the competition for empty sites. We derive the deterministic, discrete-time dynamical system for the species abundances. We prove the conditions under which plant species can coexist in a stable equilibrium. We show that the coexistence conditions can be characterized graphically, clearly illustrating the trade-off between stress tolerance and competitive ability. We compare our model with a recently proposed, continuous-time dynamical system for a tolerance-fecundity trade-off in plant communities, and we show that this model is a special case of the continuous-time version of our model.

  8. Tree Species Richness Promotes Invertebrate Herbivory on Congeneric Native and Exotic Tree Saplings in a Young Diversity Experiment.

    Directory of Open Access Journals (Sweden)

    Annika Wein

    Full Text Available Tree diversity in forests is an important driver of ecological processes including herbivory. Empirical evidence suggests both negative and positive effects of tree diversity on herbivory, which can be, respectively, attributed to associational resistance or associational susceptibility. Tree diversity experiments allow testing for associational effects, but evidence regarding which pattern predominates is mixed. Furthermore, it is unknown if herbivory on tree species of native vs. exotic origin is influenced by changing tree diversity in a similar way, or if exotic tree species escape natural enemies, resulting in lower damage that is unrelated to tree diversity. To address these questions, we established a young tree diversity experiment in temperate southwestern Germany that uses high planting density (49 trees per plot; plot size 13 m2. The species pool consists of six congeneric species pairs of European and North American origin (12 species in total planted in monocultures and mixtures (1, 2, 4, 6 species. We assessed leaf damage by leaf-chewing insects on more than 5,000 saplings of six broadleaved tree species. Plot-level tree species richness increased leaf damage, which more than doubled from monocultures to six-species mixtures, strongly supporting associational susceptibility. However, leaf damage among congeneric native and exotic species pairs was similar. There were marked differences in patterns of leaf damage across tree genera, and only the genera likely having a predominately generalist herbivore community showed associational susceptibility, irrespective of the geographical origin of a tree species. In conclusion, an increase in tree species richness in young temperate forests may result in associational susceptibility to feeding by generalist herbivores.

  9. Effects of biotic interactions and dispersal on the presence-absence of multiple species

    International Nuclear Information System (INIS)

    Mohd, Mohd Hafiz; Murray, Rua; Plank, Michael J.; Godsoe, William

    2017-01-01

    One of the important issues in ecology is to predict which species will be present (or absent) across a geographical region. Dispersal is thought to have an important influence on the range limits of species, and understanding this problem in a multi-species community with priority effects (i.e. initial abundances determine species presence-absence) is a challenging task because dispersal also interacts with biotic and abiotic factors. Here, we propose a simple multi-species model to investigate the joint effects of biotic interactions and dispersal on species presence-absence. Our results show that dispersal can substantially expand species ranges when biotic and abiotic forces are present; consequently, coexistence of multiple species is possible. The model also exhibits ecologically interesting priority effects, mediated by intense biotic interactions. In the absence of dispersal, competitive exclusion of all but one species occurs. We find that dispersal reduces competitive exclusion effects that occur in no-dispersal case and promotes coexistence of multiple species. These results also show that priority effects are still prevalent in multi-species communities in the presence of dispersal process. We also illustrate the existence of threshold values of competitive strength (i.e. transcritical bifurcations), which results in different species presence-absence in multi-species communities with and without dispersal.

  10. Body size mediated coexistence of consumers competing for resources in space

    Science.gov (United States)

    Basset, A.; Angelis, D.L.

    2007-01-01

    Body size is a major phenotypic trait of individuals that commonly differentiates co-occurring species. We analyzed inter-specific competitive interactions between a large consumer and smaller competitors, whose energetics, selection and giving-up behaviour on identical resource patches scaled with individual body size. The aim was to investigate whether pure metabolic constraints on patch behaviour of vagile species can determine coexistence conditions consistent with existing theoretical and experimental evidence. We used an individual-based spatially explicit simulation model at a spatial scale defined by the home range of the large consumer, which was assumed to be parthenogenic and semelparous. Under exploitative conditions, competitive coexistence occurred in a range of body size ratios between 2 and 10. Asymmetrical competition and the mechanism underlying asymmetry, determined by the scaling of energetics and patch behaviour with consumer body size, were the proximate determinant of inter-specific coexistence. The small consumer exploited patches more efficiently, but searched for profitable patches less effectively than the larger competitor. Therefore, body-size related constraints induced niche partitioning, allowing competitive coexistence within a set of conditions where the large consumer maintained control over the small consumer and resource dynamics. The model summarises and extends the existing evidence of species coexistence on a limiting resource, and provides a mechanistic explanation for decoding the size-abundance distribution patterns commonly observed at guild and community levels. ?? Oikos.

  11. Evolutionary acquisition of promoter-associated non-coding RNA (pancRNA) repertoires diversifies species-dependent gene activation mechanisms in mammals

    OpenAIRE

    Uesaka, Masahiro; Agata, Kiyokazu; Oishi, Takao; Nakashima, Kinichi; Imamura, Takuya

    2017-01-01

    Background Recent transcriptome analyses have shown that long non-coding RNAs (ncRNAs) play extensive roles in transcriptional regulation. In particular, we have reported that promoter-associated ncRNAs (pancRNAs) activate the partner gene expression via local epigenetic changes. Results Here, we identify thousands of genes under pancRNA-mediated transcriptional activation in five mammalian species in common. In the mouse, 1) pancRNA-partnered genes confined their expression pattern to certai...

  12. Spin wave mode coexistence on the nanoscale: A consequence of the Oersted field induced asymmetric energy landscape

    Science.gov (United States)

    Dumas, Randy

    2014-03-01

    The emerging field of magnonics relies on the systematic generation, manipulation, and detection of spin waves (SWs). Nanocontact spin torque oscillators (NC-STOs) provide an ideal platform to study spin transfer torque induced SW emission. In analogy to two species competing for the same food supply it has been argued that only one SW mode can survive in the steady state. However, as evidenced in many experiments clear signatures of mode-hopping are often observed. Here, we present a third possibility, namely that under the correct experimental conditions, mode coexistencecan be realized in NC-STOs. Micromagnetic simulations reveal that the SW modes are spatially separated under the NC. Mode coexistence is facilitated by the local field asymmetries induced by the spatially inhomogeneous Oersted field in the vicinity of the NC and further promoted by SW localization. Finally, both simulation and experiment reveal a weak low frequency signal exactly at the difference of the mode frequencies, consistent with inter-modulation of two coexistent modes. The Swedish Research Council, The Swedish Foundation for Strategic Research, and the Knut and Alice Wallenberg Foundation are acknowledged. ANL is a US DOE Science Laboratory operated under contract no. DE-AC02-06CH11357 by UChicago Argonne, LLC.

  13. Influence of body size on coexistence of bird species

    NARCIS (Netherlands)

    Leyequien Abarca, E.; Boer, de W.F.; Cleef, A.M.

    2007-01-01

    Theory suggests that body size is an important factor in determining interspecific competition and, ultimately, in structuring ecological communities. However, there is a lack of pragmatic studies linking body size and interspecific competition to patterns in ecological communities. The objective of

  14. Public Perception of Invasive Plant Species: Assessing the Impact of Workshop Activities to Promote Young Students' Awareness

    Science.gov (United States)

    Schreck Reis, Catarina; Marchante, Helia; Freitas, Helena; Marchante, Elizabete

    2013-01-01

    Invasive species are one of the main threats to biodiversity worldwide. Even though they are identified and recognized as such by the Portuguese law, the majority of the population is not yet aware of this problem. Aiming to increase awareness about biological invasions among young students, a workshop on Invasive Plant Species was organized at…

  15. Toleration and Coexistence in Conflicting Societies: Some Tensions and Implications for Education

    Science.gov (United States)

    Zembylas, Michalinos

    2011-01-01

    In this paper, the author shows that the issue of whether toleration promotes coexistence is controversial and therefore needs careful consideration in light of the complexities that are involved in understanding and teaching toleration in the schools of conflict and post-conflict societies. In particular, this paper offers a critique to the…

  16. Biofilms promote altruism.

    Science.gov (United States)

    Kreft, Jan-Ulrich

    2004-08-01

    The origin of altruism is a fundamental problem in evolution, and the maintenance of biodiversity is a fundamental problem in ecology. These two problems combine with the fundamental microbiological question of whether it is always advantageous for a unicellular organism to grow as fast as possible. The common basis for these three themes is a trade-off between growth rate and growth yield, which in turn is based on irreversible thermodynamics. The trade-off creates an evolutionary alternative between two strategies: high growth yield at low growth rate versus high growth rate at low growth yield. High growth yield at low growth rate is a case of an altruistic strategy because it increases the fitness of the group by using resources economically at the cost of decreased fitness, or growth rate, of the individual. The group-beneficial behaviour is advantageous in the long term, whereas the high growth rate strategy is advantageous in the short term. Coexistence of species requires differences between their niches, and niche space is typically divided into four 'axes' (time, space, resources, predators). This neglects survival strategies based on cooperation, which extend the possibilities of coexistence, arguing for the inclusion of cooperation as the fifth 'axis'. Here, individual-based model simulations show that spatial structure, as in, for example, biofilms, is necessary for the origin and maintenance of this 'primitive' altruistic strategy and that the common belief that growth rate but not yield decides the outcome of competition is based on chemostat models and experiments. This evolutionary perspective on life in biofilms can explain long-known biofilm characteristics, such as the structural organization into microcolonies, the often-observed lack of mixing among microcolonies, and the shedding of single cells, as promoting the origin and maintenance of the altruistic strategy. Whereas biofilms enrich altruists, enrichment cultures, microbiology's paradigm

  17. The threshold of coexistence and critical behaviour of a predator-prey cellular automaton

    International Nuclear Information System (INIS)

    Arashiro, Everaldo; Tome, Tania

    2007-01-01

    We study a probabilistic cellular automaton to describe two population biology problems: the threshold of species coexistence in a predator-prey system and the spreading of an epidemic in a population. By carrying out mean-field approximations and numerical simulations we obtain the phase boundaries (thresholds) related to the transition between an active state, where prey and predators present a stable coexistence, and a prey absorbing state. The numerical estimates for the critical exponents show that the transition belongs to the directed percolation universality class. In the limit where the cellular automaton maps into a model for the spreading of an epidemic with immunization we observe a crossover from directed percolation class to the dynamic percolation class. Patterns of growing clusters related to species coexistence and spreading of epidemic are shown and discussed

  18. Coexistence of Strategic Vertical Separation and Integration

    DEFF Research Database (Denmark)

    Jansen, Jos

    2003-01-01

    This paper gives conditions under which vertical separation is chosen by some upstream firms, while vertical integration is chosen by others in the equilibrium of a symmetric model. A vertically separating firm trades off fixed contracting costs against the strategic benefit of writing a (two......-part tariff, exclusive dealing) contract with its retailer. Coexistence emerges when more than two vertical Cournot oligopolists supply close substitutes. When vertical integration and separation coexist, welfare could be improved by reducing the number of vertically separating firms. The scope...

  19. Print vs digital the future of coexistence

    CERN Document Server

    Lee, Sul H

    2013-01-01

    Libraries are currently confronted by the challenges of managing increasing amounts of electronic information. Print vs. Digital: The Future of Coexistence presents the expert perspectives of eight of America's leading library administrators on ways to effectively manage digital flow and offers strategies to provide a level of coexistence between digital and print information. This excellent overview explores how to best balance print and electronic resources, and explores important issues such as the selection of electronic resources, improving access to digital information for a larger user

  20. EDUCATE SCHOOL COEXISTENCE AND PEACE: PRINCIPLES AND PRACTICES OF HOPE AND SHARED ACTION

    Directory of Open Access Journals (Sweden)

    Anita Yudkin-Suliveres

    2014-01-01

    Full Text Available This paper elaborates a proposal for educating in learning to live together in schools based on the principles and practices of peace education. It is based on seven thematic axis that promote educating to live together and learning in coexistence: adopting a human rights framework; generating a climate of safety, respect, and trust; promoting supportive relationships with families and communities; integrating emotional education; prioritizing receptiveness and tolerance for the appreciation of differences; fostering democratic participation; asuming nonviolent conflict resolution.

  1. Superior coexistence: systematicALLY regulatING land subsidence BASED on set pair theory

    Directory of Open Access Journals (Sweden)

    Y. Chen

    2015-11-01

    Full Text Available Anthropogenic land subsidence is an environmental side effect of exploring and using natural resources in the process of economic development. The key points of the system for controlling land subsidence include cooperation and superior coexistence while the economy develops, exploring and using natural resources, and geological environmental safety. Using the theory and method of set pair analysis (SPA, this article anatomises the factors, effects, and transformation of land subsidence. Based on the principle of superior coexistence, this paper promotes a technical approach to the system for controlling land subsidence, in order to improve the prevention and control of geological hazards.

  2. Coexistence of contrasting principles in corporate governance: Two tales of Japanese firms

    Directory of Open Access Journals (Sweden)

    Taeyoung Yoo

    2015-09-01

    Full Text Available The underlying logic that shapes the coexistence of contrasting mechanisms in a firm’s governance system remains unclear. We examine the logic that promotes a hybrid form of corporate governance in functional terms. The empirical analysis of Japanese firms shows that a firm’s reliance on capital markets for resource acquisition facilitates its adoption of shareholder-oriented mechanisms, such as committee systems. In contrast, corporate performance is still influenced by some of Japanese society’s characteristic governance mechanisms, such as bank ownership. This finding illustrates that contrasting governance mechanisms coexist in a given system owing to their respective or interacting contributions to corporate performance.

  3. Shape coexistence in light Xe-isotopes

    International Nuclear Information System (INIS)

    Gast, K.F.W.

    1982-01-01

    There are essentially four regions of problems which are discussed in the framework of this thesis. They can be entitled as follows: Backbending and the nature of the S-band, Nuclear softness and shape coexistence, the validity of the IBA-approximation, and the boson cutoff effect. (orig./HSI) [de

  4. Introduction to the Issue of Coexistence

    NARCIS (Netherlands)

    Kalaitzandonakes, N.; Philips, P.C.; Smyth, S.; Wesseler, J.H.H.

    2016-01-01

    In many ways, the debate about coexistence is about the future of the global food system and its capacity to meet the rapidly growing demand for food and nutrition. Since their commercial introduction in 1995 and 1996, genetically modified (GM) crops have been adopted by farmers around the world at

  5. Coexisting tensions between the 'traditionmodernity' and the ...

    African Journals Online (AJOL)

    Coexisting tensions between the 'traditionmodernity' and the 'sustainability- integration' approaches to urban development policy and planning practices in Botswana. ... exists at several levels and manifest in urban planning's preoccupation with the physicality of spatial forms, often justified in the embracing of globalization.

  6. Hashimotos Thyroiditis with Coexistent Papillary Carcinoma and ...

    African Journals Online (AJOL)

    final diagnosis of HT coexisting with papillary carcinoma and primary NHL (B-cell lineage) was made. Levothyroxine was initiated at 300mcg/day and patient was treated with chemotherapy (R-CHOP regime). Patient tolerated the chemotherapy well and with 12 months of follow-up, no recurrence or metastasis was noted.

  7. New oenological practice to promote non-Saccharomyces species of interest: saturating grape juice with carbon dioxide.

    Science.gov (United States)

    Chasseriaud, Laura; Coulon, Joana; Marullo, Philippe; Albertin, Warren; Bely, Marina

    2018-04-01

    Non-Saccharomyces yeast species, naturally found in grape must, may impact wine quality positively or negatively. In this study, a mixture of five non-Saccharomyces species (Torulaspora delbrueckii, Metschnikowia spp., Starmerella bacillaris (formerly called Candida zemplinina), Hanseniaspora uvarum, Pichia kluyveri), mimicking the composition of the natural non-Saccharomyces community found in grape must, was used for alcoholic fermentation. The impact of CO 2 saturation of the grape juice was studied first on this mixture alone, and then in the presence of Saccharomyces cerevisiae. Two isogenic strains of this species were used: the first with a short and the second a long fermentation lag phase. This study demonstrated that saturating grape juice with CO 2 had interesting potential as an oenological technique, inhibiting undesirable species (S. bacillaris and H. uvarum) and stimulating non-Saccharomyces of interest (T. delbrueckii and P. kluyveri). This stimulating effect was particularly marked when CO 2 saturation was associated with the presence of S. cerevisiae with long fermentation lag phase. The direct consequence of this association was an enhancement of 3-SH levels in the resulting wine.

  8. Links between belowground and aboveground resource-related traits reveal species growth strategies that promote invasive advantages.

    Science.gov (United States)

    Smith, Maria S; Fridley, Jason D; Goebel, Marc; Bauerle, Taryn L

    2014-01-01

    Belowground processes are rarely considered in comparison studies of native verses invasive species. We examined relationships between belowground fine root production and lifespan, leaf phenology, and seasonal nitrogen dynamics of Lonicera japonica (non-native) versus L. sempervirens (native) and Frangula alnus (non-native) versus Rhamnus alnifolia (native), over time. First and second order fine roots were monitored from 2010 to 2012 using minirhizotron technology and rhizotron windows. 15N uptake of fine roots was measured across spring and fall seasons. Significant differences in fine root production across seasons were seen between Lonicera species, but not between Frangula and Rhamnus, with both groups having notable asynchrony in regards to the timing of leaf production. Root order and the number of root neighbors at the time of root death were the strongest predictors of root lifespan of both species pairs. Seasonal 15N uptake was higher in spring than in the fall, which did not support the need for higher root activity to correspond with extended leaf phenology. We found higher spring 15N uptake in non-native L. japonica compared to native L. sempervirens, although there was no difference in 15N uptake between Frangula and Rhamnus species. Our findings indicate the potential for fast-growing non-native Lonicera japonica and Frangula alnus to outcompete native counterparts through differences in biomass allocation, root turnover, and nitrogen uptake, however evidence that this is a general strategy of invader dominance is limited.

  9. Links between belowground and aboveground resource-related traits reveal species growth strategies that promote invasive advantages.

    Directory of Open Access Journals (Sweden)

    Maria S Smith

    Full Text Available Belowground processes are rarely considered in comparison studies of native verses invasive species. We examined relationships between belowground fine root production and lifespan, leaf phenology, and seasonal nitrogen dynamics of Lonicera japonica (non-native versus L. sempervirens (native and Frangula alnus (non-native versus Rhamnus alnifolia (native, over time. First and second order fine roots were monitored from 2010 to 2012 using minirhizotron technology and rhizotron windows. 15N uptake of fine roots was measured across spring and fall seasons. Significant differences in fine root production across seasons were seen between Lonicera species, but not between Frangula and Rhamnus, with both groups having notable asynchrony in regards to the timing of leaf production. Root order and the number of root neighbors at the time of root death were the strongest predictors of root lifespan of both species pairs. Seasonal 15N uptake was higher in spring than in the fall, which did not support the need for higher root activity to correspond with extended leaf phenology. We found higher spring 15N uptake in non-native L. japonica compared to native L. sempervirens, although there was no difference in 15N uptake between Frangula and Rhamnus species. Our findings indicate the potential for fast-growing non-native Lonicera japonica and Frangula alnus to outcompete native counterparts through differences in biomass allocation, root turnover, and nitrogen uptake, however evidence that this is a general strategy of invader dominance is limited.

  10. Soil seed banks in plant invasions: promoting species invasiveness and long-term impakt on plant community dynamics

    Czech Academy of Sciences Publication Activity Database

    Gioria, M.; Pyšek, Petr; Moravcová, Lenka

    2012-01-01

    Roč. 84, č. 2 (2012), s. 327-350 ISSN 0032-7786 R&D Projects: GA ČR GA206/09/0563 Institutional support: RVO:67985939 Keywords : soil seed bank * plant invasions * species invasive ness Subject RIV: EF - Botanics Impact factor: 2.833, year: 2012

  11. Small habitat size and isolation can promote species richness: second-order effects on biodiversity in shallow lakes and ponds

    NARCIS (Netherlands)

    Scheffer, M.; Van Geest, G.J.; Zimmer, K.; Jeppesen, E.; Søndergaard, M.; Butler, M.G.; Hanson, M.A.; Declerck, S.A.J.; De Meester, L.

    2006-01-01

    Contemporary ecological landscape planning is often based on the assumption that small isolated habitat patches sustain relatively few species. Here, we suggest that for shallow lakes and ponds, the opposite can be true for some groups of organisms. Fish communities tend to be poor or even absent in

  12. Species associations structured by environment and land-use history promote beta-diversity in a temperate forest.

    Science.gov (United States)

    Murphy, Stephen J; Audino, Livia D; Whitacre, James; Eck, Jenalle L; Wenzel, John W; Queenborough, Simon A; Comita, Liza S

    2015-03-01

    Patterns of diversity and community composition in forests are controlled by a combination of environmental factors, historical events, and stochastic or neutral mechanisms. Each of these processes has been linked to forest community assembly, but their combined contributions to alpha and beta-diversity in forests has not been well explored. Here we use variance partitioning to analyze approximately 40,000 individual trees of 49 species, collected within 137 ha of sampling area spread across a 900-ha temperate deciduous forest reserve in Pennsylvania to ask (1) To what extent is site-to-site variation in species richness and community composition of a temperate forest explained by measured environmental gradients and by spatial descriptors (used here to estimate dispersal-assembly or unmeasured, spatially structured processes)? (2) How does the incorporation of land-use history information increase the importance attributed to deterministic community assembly? and (3) How do the distributions and abundances of individual species within the community correlate with these factors? Environmental variables (i.e., topography, soils, and distance to stream), spatial descriptors (i.e., spatial eigenvectors derived from Cartesian coordinates), and land-use history variables (i.e., land-use type and intensity, forest age, and distance to road), explained about half of the variation in both species richness and community composition. Spatial descriptors explained the most variation, followed by measured environmental variables and then by land- use history. Individual species revealed variable responses to each of these sets of predictor variables. Several species were associated with stream habitats, and others were strictly delimited across opposing north- and south-facing slopes. Several species were also associated with areas that experienced recent (i.e., indicate that deterministic factors, including environmental and land-use history variables, are important drivers

  13. Contrasting Evolutionary Paths Among Indo-Pacific Pomacentrus Species Promoted by Extensive Pericentric Inversions and Genome Organization of Repetitive Sequences.

    Science.gov (United States)

    Getlekha, Nuntaporn; Cioffi, Marcelo de Bello; Maneechot, Nuntiya; Bertollo, Luiz Antônio Carlos; Supiwong, Weerayuth; Tanomtong, Alongklod; Molina, Wagner Franco

    2018-02-01

    Pomacentrus (damselfishes) is one of the most characteristic groups of fishes in the Indo-Pacific coral reef. Its 77 described species exhibit a complex taxonomy with cryptic lineages across their extensive distribution. Periods of evolutionary divergences between them are very variable, and the cytogenetic events that followed their evolutionary diversification are largely unknown. In this respect, analyses of chromosomal divergence, within a phylogenetic perspective, are particularly informative regarding karyoevolutionary trends. As such, we conducted conventional cytogenetic and cytogenomic analyses in four Pomacentrus species (Pomacentrus similis, Pomacentrus auriventris, Pomacentrus moluccensis, and Pomacentrus cuneatus), through the mapping of repetitive DNA classes and transposable elements, including 18S rDNA, 5S rDNA, (CA) 15 , (GA) 15 , (CAA) 10 , Rex6, and U2 snDNA as markers. P. auriventris and P. similis, belonging to the Pomacentrus coelestis complex, have indistinguishable karyotypes (2n = 48; NF = 48), with a peculiar syntenic organization of ribosomal genes. On the other hand, P. moluccensis and P. cuneatus, belonging to another clade, exhibit very different karyotypes (2n = 48, NF = 86 and 92, respectively), with a large number of bi-armed chromosomes, where multiple pericentric inversions played a significant role in their karyotype organization. In this sense, different chromosomal pathways followed the phyletic diversification in the Pomacentrus genus, making possible the characterization of two well-contrasting species groups regarding their karyotype features. Despite this, pericentric inversions act as an effective postzygotic barrier in many organisms, which appear to be also the case for P. moluccensis and P. cuneatus; the extensive chromosomal similarities in the two species of P. coelestis complex suggest minor participation of chromosomal postzygotic barriers in the phyletic diversification of these species.

  14. Coexistence of coyotes (Canis latrans) and red foxes (Vulpes vulpes) in an urban landscape

    Science.gov (United States)

    Drake, David; Allen, Maximilian L.

    2018-01-01

    Urban environments are increasing worldwide and are inherently different than their rural counterparts, with a variety of effects on wildlife due to human presence, increased habitat fragmentation, movement barriers, and access to anthropogenic food sources. Effective management of urban wildlife requires an understanding of how urbanization affects their behavior and ecology. The spatial activity and interactions of urban wildlife, however, have not been as rigorously researched as in rural areas. From January 2015 to December 2016, we captured, radio-collared, and tracked 11 coyotes and 12 red foxes in Madison, WI. Within our study area, coyotes strongly selected home ranges with high proportions of natural areas; conversely, red foxes selected home ranges with open space and moderately developed areas. Use of highly developed areas best explained variation among individual home range sizes and inversely affected home range size for coyotes and red foxes. Coyote and red fox home ranges showed some degree of spatial and temporal overlap, but generally appeared partitioned by habitat type within our study area. Coyotes and red foxes were both active at similar times of the day, but their movement patterns differed based on species-specific habitat use. This spatial partitioning may promote positive co-existence between these sympatric canids in urban areas, and our findings of spatial activity and interactions will better inform wildlife managers working in urban areas. PMID:29364916

  15. Coexistence of coyotes (Canis latrans) and red foxes (Vulpes vulpes) in an urban landscape.

    Science.gov (United States)

    Mueller, Marcus A; Drake, David; Allen, Maximilian L

    2018-01-01

    Urban environments are increasing worldwide and are inherently different than their rural counterparts, with a variety of effects on wildlife due to human presence, increased habitat fragmentation, movement barriers, and access to anthropogenic food sources. Effective management of urban wildlife requires an understanding of how urbanization affects their behavior and ecology. The spatial activity and interactions of urban wildlife, however, have not been as rigorously researched as in rural areas. From January 2015 to December 2016, we captured, radio-collared, and tracked 11 coyotes and 12 red foxes in Madison, WI. Within our study area, coyotes strongly selected home ranges with high proportions of natural areas; conversely, red foxes selected home ranges with open space and moderately developed areas. Use of highly developed areas best explained variation among individual home range sizes and inversely affected home range size for coyotes and red foxes. Coyote and red fox home ranges showed some degree of spatial and temporal overlap, but generally appeared partitioned by habitat type within our study area. Coyotes and red foxes were both active at similar times of the day, but their movement patterns differed based on species-specific habitat use. This spatial partitioning may promote positive co-existence between these sympatric canids in urban areas, and our findings of spatial activity and interactions will better inform wildlife managers working in urban areas.

  16. Phytoplankton abundance, dominance and coexistence in an eutrophic reservoir in the state of Pernambuco, Northeast Brazil.

    Science.gov (United States)

    Lira, Giulliari A S T; Araújo, Elcida L; Bittencourt-Oliveira, Maria Do Carmo; Moura, Ariadne N

    2011-12-01

    The present study reports the phytoplankton abundance, dominance and co-existence relationships in the eutrophic Carpina reservoir, Pernambuco, Brazil. Sampling was carried out at six different depths bimonthly at a single reservoir spanning two climatic periods: dry season (January, September, and November 2006) and rainy season (March, May, and July 2006). Density, abundance, dominance, specific diversity and equitability of the community were determined, along with chlorophyll a, and physical and chemical variables of the environment. Eight species were considered abundant, and their densities corresponded to more than 90% of the total phytoplankton community quantified. Cyanobacteria represented more than 80% of this density. Cylindrospermopsis raciborskii was the only dominant taxon in the dry season, and was co-dominant in the rainy season. C. raciborskii, Planktothrix agardhii and Geitlerinema amphibium had the greatest densities and lowest vertical variation coefficients. The statistical analysis indicated relationships with vertical and seasonal variations in the phytoplankton community and the following variables: total dissolved solids, water temperature, electrical conductivity and pH. The changes in the environmental variables were discrete and regulated by the establishment of precipitation however, they were able to promote vertical and seasonal instability in the structure of the phytoplankton community.

  17. Evidence from Individual Inference for High-Dimensional Coexistence: Long-Term Experiments on Recruitment Response

    Science.gov (United States)

    Clark, James S.; Soltoff, Benjamin D.; Powell, Amanda S.; Read, Quentin D.

    2012-01-01

    Background For competing species to coexist, individuals must compete more with others of the same species than with those of other species. Ecologists search for tradeoffs in how species might partition the environment. The negative correlations among competing species that would be indicative of tradeoffs are rarely observed. A recent analysis showed that evidence for partitioning the environment is available when responses are disaggregated to the individual scale, in terms of the covariance structure of responses to environmental variation. That study did not relate that variation to the variables to which individuals were responding. To understand how this pattern of variation is related to niche variables, we analyzed responses to canopy gaps, long viewed as a key variable responsible for species coexistence. Methodology/Principal Findings A longitudinal intervention analysis of individual responses to experimental canopy gaps with 12 yr of pre-treatment and 8 yr post-treatment responses showed that species-level responses are positively correlated – species that grow fast on average in the understory also grow fast on average in response to gap formation. In other words, there is no tradeoff. However, the joint distribution of individual responses to understory and gap showed a negative correlation – species having individuals that respond most to gaps when previously growing slowly also have individuals that respond least to gaps when previously growing rapidly (e.g., Morus rubra), and vice versa (e.g., Quercus prinus). Conclusions/Significance Because competition occurs at the individual scale, not the species scale, aggregated species-level parameters and correlations hide the species-level differences needed for coexistence. By disaggregating models to the scale at which the interaction occurs we show that individual variation provides insight for species differences. PMID:22393349

  18. Evidence from individual inference for high-dimensional coexistence: long-term experiments on recruitment response.

    Directory of Open Access Journals (Sweden)

    James S Clark

    Full Text Available BACKGROUND: For competing species to coexist, individuals must compete more with others of the same species than with those of other species. Ecologists search for tradeoffs in how species might partition the environment. The negative correlations among competing species that would be indicative of tradeoffs are rarely observed. A recent analysis showed that evidence for partitioning the environment is available when responses are disaggregated to the individual scale, in terms of the covariance structure of responses to environmental variation. That study did not relate that variation to the variables to which individuals were responding. To understand how this pattern of variation is related to niche variables, we analyzed responses to canopy gaps, long viewed as a key variable responsible for species coexistence. METHODOLOGY/PRINCIPAL FINDINGS: A longitudinal intervention analysis of individual responses to experimental canopy gaps with 12 yr of pre-treatment and 8 yr post-treatment responses showed that species-level responses are positively correlated--species that grow fast on average in the understory also grow fast on average in response to gap formation. In other words, there is no tradeoff. However, the joint distribution of individual responses to understory and gap showed a negative correlation--species having individuals that respond most to gaps when previously growing slowly also have individuals that respond least to gaps when previously growing rapidly (e.g., Morus rubra, and vice versa (e.g., Quercus prinus. CONCLUSIONS/SIGNIFICANCE: Because competition occurs at the individual scale, not the species scale, aggregated species-level parameters and correlations hide the species-level differences needed for coexistence. By disaggregating models to the scale at which the interaction occurs we show that individual variation provides insight for species differences.

  19. Bacillus species (BT42) isolated from Coffea arabica L. rhizosphere antagonizes Colletotrichum gloeosporioides and Fusarium oxysporum and also exhibits multiple plant growth promoting activity.

    Science.gov (United States)

    Kejela, Tekalign; Thakkar, Vasudev R; Thakor, Parth

    2016-11-18

    Colletotrichum and Fusarium species are among pathogenic fungi widely affecting Coffea arabica L., resulting in major yield loss. In the present study, we aimed to isolate bacteria from root rhizosphere of the same plant that is capable of antagonizing Colletotrichum gloeosporioides and Fusarium oxysporum as well as promotes plant growth. A total of 42 Bacillus species were isolated, one of the isolates named BT42 showed maximum radial mycelial growth inhibition against Colletotrichum gloeosporioides (78%) and Fusarium oxysporum (86%). BT42 increased germination of Coffee arabica L. seeds by 38.89%, decreased disease incidence due to infection of Colletotrichum gloeosporioides to 2.77% and due to infection of Fusarium oxysporum to 0 (p Fusarium oxysporum. The mechanism of action of inhibition of the pathogenic fungi found to be synergistic effects of secondary metabolites, lytic enzymes, and siderophores. The major inhibitory secondary metabolite identified as harmine (β-carboline alkaloids).

  20. Restoration of Degraded Soil in the Nanmangalam Reserve Forest with Native Tree Species: Effect of Indigenous Plant Growth-Promoting Bacteria.

    Science.gov (United States)

    Ramachandran, Andimuthu; Radhapriya, Parthasarathy

    Restoration of a highly degraded forest, which had lost its natural capacity for regeneration, was attempted in the Nanmangalam Reserve Forest in Eastern Ghats of India. In field experiment, 12 native tree species were planted. The restoration included inoculation with a consortium of 5 native plant growth-promoting bacteria (PGPB), with the addition of small amounts of compost and a chemical fertilizer (NPK). The experimental fields were maintained for 1080 days. The growth and biomass varied depending on the plant species. All native plants responded well to the supplementation with the native PGPB. The plants such as Pongamia pinnata, Tamarindus indica, Gmelina arborea, Wrightia tinctoria, Syzygium cumini, Albizia lebbeck, Terminalia bellirica, and Azadirachta indica performed well in the native soil. This study demonstrated, by using native trees and PGPB, a possibility to restore the degraded forest.

  1. Restoration of Degraded Soil in the Nanmangalam Reserve Forest with Native Tree Species: Effect of Indigenous Plant Growth-Promoting Bacteria

    Directory of Open Access Journals (Sweden)

    Andimuthu Ramachandran

    2016-01-01

    Full Text Available Restoration of a highly degraded forest, which had lost its natural capacity for regeneration, was attempted in the Nanmangalam Reserve Forest in Eastern Ghats of India. In field experiment, 12 native tree species were planted. The restoration included inoculation with a consortium of 5 native plant growth-promoting bacteria (PGPB, with the addition of small amounts of compost and a chemical fertilizer (NPK. The experimental fields were maintained for 1080 days. The growth and biomass varied depending on the plant species. All native plants responded well to the supplementation with the native PGPB. The plants such as Pongamia pinnata, Tamarindus indica, Gmelina arborea, Wrightia tinctoria, Syzygium cumini, Albizia lebbeck, Terminalia bellirica, and Azadirachta indica performed well in the native soil. This study demonstrated, by using native trees and PGPB, a possibility to restore the degraded forest.

  2. TEACHING, COEXISTENCE AND ATTENDANCE AT A TECHNOLOGICAL HIGH SCHOOL

    Directory of Open Access Journals (Sweden)

    Leticia Carranza-Peña

    2015-01-01

    Full Text Available This article, which stems from ethnographic research, shows the importance of faculty intervention in the classroom setting in encouraging student attendance. Our findings indicate that the habitus the educator establishes can either encourage youth to continue their studies, or lead them to drop out, thus placing them at risk of addictions, illegal activities, unemployment or low-paid jobs. The Pedagogy of Hope therefore provides an option for effecting large-scale changes in personal, school, family, community and socio-economic conditions. The paper’s conclusions include providing training to teaching faculties on coexistence issues; ensuring coordination between school and family, and emphasizing an integral approach to education as means of promoting school attendance.

  3. Coexistence in neutral theories: interplay of criticality and mild local preferences

    International Nuclear Information System (INIS)

    Borile, Claudio; Molina-Garcia, Daniel; Muñoz, Miguel A; Maritan, Amos

    2015-01-01

    Neutral theories have played a crucial and revolutionary role in fields such as population genetics and biogeography. These theories are critical by definition, in the sense that the overall growth rate of each single allele/species/type vanishes. Thus each species in a neutral model sits at the edge between invasion and extinction, allowing for the coexistence of symmetric/neutral types. However, in finite systems, mono-dominated states are ineluctably reached in relatively short times owing to demographic fluctuations, thus leaving us with an unsatisfactory framework to rationalize empirically-observed long-term coexistence. Here, we scrutinize the effect of heterogeneity in quasi-neutral theories, in which there can be a local mild preference for some of the competing species at some sites, even if the overall species symmetry is maintained. As we show here, mild biases at a small fraction of locations suffice to induce overall robust and durable species coexistence, even in regions arbitrarily far apart from the biased locations. This result stems from the long-range nature of the underlying critical bulk dynamics and has a number of implications, for example, in conservation ecology as it suggests that constructing local specific ‘sanctuaries’ for different competing species can result in global enhancement of biodiversity, even in regions arbitrarily distant from the protected refuges. (paper)

  4. Species distribution and resistance patterns to growth-promoting antimicrobials of enterococci isolated from pigs and chickens in Korea.

    Science.gov (United States)

    Hwang, In Yeong; Ku, Hyun Ok; Lim, Suk Kyung; Park, Choi Kyu; Jung, Gab Su; Jung, Suk Chan; Nam, Hyang Mi

    2009-11-01

    A total of 147 Enterococcus faecium and 165 Enterococcus faecalis isolates from fecal samples of chickens and pigs at slaughterhouses in Korea were tested for their resistance to 8 growth-promoting antimicrobials commonly used in animals and quinupristin and dalfopristin. Resistance to most antimicrobials was very common among both E. faecalis and E. faecium. In particular, E. faecalis showed almost no susceptibility to all the antimicrobials tested except penicillin and flavomycin, to which 1.4% and less than 24% showed resistance, respectively. Although the prevalence of resistance was lower than in E. faecalis, E. faecium showed relatively uniform resistance to all the agents tested. Among the antimicrobials tested, virginiamycin and penicillin were the most effective against E. faecium isolates: less than 31% and 41% showed resistance to those 2 antimicrobials, respectively. Penicillin was the only agent that showed relatively strong activity against both E. faecalis and E. faecium. Resistance observed in E. faecalis and E. faecium against most antimicrobials used for growth promotion was more prevalent in Korea than in European countries. The current study is the first report of resistance against feed additive antimicrobials in enterococcal isolates from livestock in Korea.

  5. Phase coexistence properties of polarizable Stockmayer fluids

    International Nuclear Information System (INIS)

    Kiyohara, K.; Gubbins, K.E.; Panagiotopoulos, A.Z.

    1997-01-01

    We report the phase coexistence properties of polarizable Stockmayer fluids of reduced permanent dipoles |m 0 * |= 1.0 and 2.0 and reduced polarizabilities α * = 0.00, 0.03, and 0.06, calculated by a series of grand canonical Monte Carlo simulations with the histogram reweighting method. In the histogram reweighting method, the distributions of density and energy calculated in Grand Canonical Monte Carlo simulations are stored in histograms and analyzed to construct the grand canonical partition function of the system. All thermodynamic properties are calculated from the grand partition function. The results are compared with Wertheim close-quote s renormalization perturbation theory. Deviations between theory and simulation results for the coexistence envelope are near 2% for the lower dipole moment and 10% for the higher dipole moment we studied. copyright 1997 American Institute of Physics

  6. Coexistence and sport: the Israeli case

    Directory of Open Access Journals (Sweden)

    Yair Galily

    2013-12-01

    Full Text Available Utilizing sports and other recreational activities to foster peaceful relations and coexistence is an idea that has gained popularity in recent years, particularly in Israel. The aim of the current research is to fill a gap in the research literature on the subject of coexistence programming. The Mifalot organization conducts a program called “Get to Know Your Neighbor” in which Palestinian, Jordanian, and Israeli youth play soccer together. The program, based mainly on the participants’ love for football, is a series of activities and lessons designed to prepare children to meet and interact with youth from neighboring communities. The study examines the effects of participation in this program on the attitudes of the Palestinians, Jordanians, and Israelis toward each other.

  7. Coexisting chondroblastoma and osteochondroma: a case report.

    Directory of Open Access Journals (Sweden)

    Pardiwala D

    2002-04-01

    Full Text Available The coexistence of two different types of benign cartilaginous tumours of bone in the same patient has not been reported in literature. We report a case in which a sixteen-year-old male had a benign chondroblastoma of the proximal left humerus and an osteochondroma of the distal left femur. Both originated at the same time and had a progressive increase in size with growth.

  8. Advanced glycation end products promote ChREBP expression and cell proliferation in liver cancer cells by increasing reactive oxygen species.

    Science.gov (United States)

    Chen, Hanbei; Li, Yakui; Zhu, Yemin; Wu, Lifang; Meng, Jian; Lin, Ning; Yang, Dianqiang; Li, Minle; Ding, WenJin; Tong, Xuemei; Su, Qing

    2017-08-01

    The aim of the study was to elucidate the mechanism by which advanced glycation end products (AGEs) promote cell proliferation in liver cancer cells.We treated liver cancer HepG2 cells with 200 mg/L AGEs or bovine serum albumin (BSA) and assayed for cell viability, cell cycle, and apoptosis. We performed real-time PCR and Western blot analysis for RNA and protein levels of carbohydrate responsive element-binding protein (ChREBP) in AGEs- or BSA-treated HepG2 cells. We analyzed the level of reactive oxygen species (ROS) in HepG2 cells treated with AGEs or BSA.We found that increased S-phase cell percentage and decreased apoptosis contributed to AGEs-induced liver cancer cell proliferation. Real-time PCR and Western blot analysis showed that AGEs stimulated RNA and protein levels of ChREBP, a transcription factor promoting glycolysis and maintaining cell proliferation in liver cancer cells. Intriguingly, the level of ROS was higher in AGEs-treated liver cancer cells. Treating liver cancer cells with antioxidant N-acetyl cystein (NAC) partly blocked AGEs-induced ChREBP expression and cell proliferation.Our results suggest that the AGEs-ROS-ChREBP pathway plays a critical role in promoting ChREBP expression and liver cancer cell proliferation.

  9. What is the mechanism for persistent coexistence of drug-susceptible and drug-resistant strains of Streptococcus pneumoniae?

    Science.gov (United States)

    Colijn, Caroline; Cohen, Ted; Fraser, Christophe; Hanage, William; Goldstein, Edward; Givon-Lavi, Noga; Dagan, Ron; Lipsitch, Marc

    2010-01-01

    The rise of antimicrobial resistance in many pathogens presents a major challenge to the treatment and control of infectious diseases. Furthermore, the observation that drug-resistant strains have risen to substantial prevalence but have not replaced drug-susceptible strains despite continuing (and even growing) selective pressure by antimicrobial use presents an important problem for those who study the dynamics of infectious diseases. While simple competition models predict the exclusion of one strain in favour of whichever is ‘fitter’, or has a higher reproduction number, we argue that in the case of Streptococcus pneumoniae there has been persistent coexistence of drug-sensitive and drug-resistant strains, with neither approaching 100 per cent prevalence. We have previously proposed that models seeking to understand the origins of coexistence should not incorporate implicit mechanisms that build in stable coexistence ‘for free’. Here, we construct a series of such ‘structurally neutral’ models that incorporate various features of bacterial spread and host heterogeneity that have been proposed as mechanisms that may promote coexistence. We ask to what extent coexistence is a typical outcome in each. We find that while coexistence is possible in each of the models we consider, it is relatively rare, with two exceptions: (i) allowing simultaneous dual transmission of sensitive and resistant strains lets coexistence become a typical outcome, as does (ii) modelling each strain as competing more strongly with itself than with the other strain, i.e. self-immunity greater than cross-immunity. We conclude that while treatment and contact heterogeneity can promote coexistence to some extent, the in-host interactions between strains, particularly the interplay between coinfection, multiple infection and immunity, play a crucial role in the long-term population dynamics of pathogens with drug resistance. PMID:19940002

  10. Different temperatures select distinctive acetic acid bacteria species and promotes organic acids production during Kombucha tea fermentation.

    Science.gov (United States)

    De Filippis, Francesca; Troise, Antonio Dario; Vitaglione, Paola; Ercolini, Danilo

    2018-08-01

    Kombucha is a traditional beverage produced by tea fermentation, carried out by a symbiotic consortium of bacteria and yeasts. Acetic Acid Bacteria (AAB) usually dominate the bacterial community of Kombucha, driving the fermentative process. The consumption of this beverage was often associated to beneficial effects for the health, due to its antioxidant and detoxifying properties. We characterized bacterial populations of Kombucha tea fermented at 20 or 30 °C by using culture-dependent and -independent methods and monitored the concentration of gluconic and glucuronic acids, as well as of total polyphenols. We found significant differences in the microbiota at the two temperatures. Moreover, different species of Gluconacetobacter were selected, leading to a differential abundance of gluconic and glucuronic acids. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Methylobacterium Species Promoting Rice and Barley Growth and Interaction Specificity Revealed with Whole-Cell Matrix-Assisted Laser Desorption/Ionization-Time-of-Flight Mass Spectrometry (MALDI-TOF/MS Analysis.

    Directory of Open Access Journals (Sweden)

    Akio Tani

    Full Text Available Methylobacterium species frequently inhabit plant surfaces and are able to utilize the methanol emitted from plants as carbon and energy sources. As some of the Methylobacterium species are known to promote plant growth, significant attention has been paid to the mechanism of growth promotion and the specificity of plant-microbe interactions. By screening our Methylobacterium isolate collection for the high growth promotion effect in vitro, we selected some candidates for field and pot growth tests for rice and barley, respectively. We found that inoculation resulted in better ripening of rice seeds, and increased the size of barley grains but not the total yield. In addition, using whole-cell matrix-assister laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF/MS analysis, we identified and classified Methylobacterium isolates from Methylobacterium-inoculated rice plants. The inoculated species could not be recovered from the rice plants, and in some cases, the Methylobacterium community structure was affected by the inoculation, but not with predomination of the inoculated species. The isolates from non-inoculated barley of various cultivars grown in the same field fell into just two species. These results suggest that there is a strong selection pressure at the species level of Methylobacterium residing on a given plant species, and that selection of appropriate species that can persist on the plant is important to achieve growth promotion.

  12. Climate reconstruction analysis using coexistence likelihood estimation (CRACLE): a method for the estimation of climate using vegetation.

    Science.gov (United States)

    Harbert, Robert S; Nixon, Kevin C

    2015-08-01

    • Plant distributions have long been understood to be correlated with the environmental conditions to which species are adapted. Climate is one of the major components driving species distributions. Therefore, it is expected that the plants coexisting in a community are reflective of the local environment, particularly climate.• Presented here is a method for the estimation of climate from local plant species coexistence data. The method, Climate Reconstruction Analysis using Coexistence Likelihood Estimation (CRACLE), is a likelihood-based method that employs specimen collection data at a global scale for the inference of species climate tolerance. CRACLE calculates the maximum joint likelihood of coexistence given individual species climate tolerance characterization to estimate the expected climate.• Plant distribution data for more than 4000 species were used to show that this method accurately infers expected climate profiles for 165 sites with diverse climatic conditions. Estimates differ from the WorldClim global climate model by less than 1.5°C on average for mean annual temperature and less than ∼250 mm for mean annual precipitation. This is a significant improvement upon other plant-based climate-proxy methods.• CRACLE validates long hypothesized interactions between climate and local associations of plant species. Furthermore, CRACLE successfully estimates climate that is consistent with the widely used WorldClim model and therefore may be applied to the quantitative estimation of paleoclimate in future studies. © 2015 Botanical Society of America, Inc.

  13. Can cat predation help competitors coexist in seabird communities?

    Science.gov (United States)

    Pontier, Dominique; Fouchet, David; Bried, Joël

    2010-01-07

    On oceanic islands, nest site availability can be an important factor regulating seabird population dynamics. The potential for birds to secure a nest to reproduce can be an important component of their life histories. The dates at which different seabird species arrive at colonies to breed will have important consequences for their relative chances of success. Early arrival on the island allows birds to obtain nests more easily and have higher reproductive success. However, the presence of an introduced predator may reverse this situation. For instance, in the sub-Antarctic Kerguelen archipelago, early arriving birds suffer heavy predation from introduced cats. Cats progressively switch from seabirds to rabbits, since the local rabbit population starts to peak after early arriving seabird species have already returned to the colony. When late-arriving birds arrive, cat predation pressure on seabirds is thus weaker. In this paper, we investigate the assumption that the advantage of early nest mnopolization conferred to early arriving birds may be counterbalanced by the cost resulting from predation. We develop a mathematical model representing a simplified situation in which two insular seabird species differ only in their arrival date at the colony site and compete for nesting sites. We conclude that predation may ensure the coexistence of the two bird species or favor the late-arriving species, but only when seasonal variations in predation pressure are large. Interestingly, we conclude that arriving early is only favorable until a given level where high reproductive success no longer compensates for the long exposure to strong predation pressure. Our work suggests that predation can help to maintain the balance between species of different phenologies.

  14. A mutation in the mitochondrial protein UQCRB promotes angiogenesis through the generation of mitochondrial reactive oxygen species

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Junghwa [Chemical Genomics National Research Lab., Department of Biotechnology, Translational Research Center for Protein Function Control, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749 (Korea, Republic of); Jung, Hye Jin [Department of Pharmaceutical Engineering, Sun Moon University, Asansi, Chungnam 330-150 (Korea, Republic of); Jeong, Seung Hun; Kim, Hyoung Kyu; Han, Jin [National Research Laboratory for Mitochondrial Signaling, Department of Physiology, College of Medicine, Department of Health Sciences and Technology, Cardiovascular and Metabolic Disease Center, Inje University, Busan (Korea, Republic of); Kwon, Ho Jeong, E-mail: kwonhj@yonsei.ac.kr [Chemical Genomics National Research Lab., Department of Biotechnology, Translational Research Center for Protein Function Control, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749 (Korea, Republic of); Department of Internal Medicine, Yonsei University College of Medicine, Seoul 120-752 (Korea, Republic of)

    2014-12-12

    Highlights: • We constructed mitochondrial protein UQCRB mutant stable cell lines on the basis of a human case report. • These mutant cell lines exhibit pro-angiogenic activity with enhanced VEGF expression. • Proliferation of mutant cell lines was regulated by UQCRB inhibitors. • UQCRB may have a functional role in angiogenesis. - Abstract: Ubiquinol-cytochrome c reductase binding protein (UQCRB) is one of the subunits of mitochondrial complex III and is a target protein of the natural anti-angiogenic small molecule terpestacin. Previously, the biological role of UQCRB was thought to be limited to the maintenance of complex III. However, the identification and validation of UQCRB as a target protein of terpestacin enabled the role of UQCRB in oxygen sensing and angiogenesis to be elucidated. To explore the biological role of this protein further, UQCRB mutant stable cell lines were generated on the basis of a human case report. We demonstrated that these cell lines exhibited glycolytic and pro-angiogenic activities via mitochondrial reactive oxygen species (mROS)-mediated HIF1 signal transduction. Furthermore, a morphological abnormality in mitochondria was detected in UQCRB mutant stable cell lines. In addition, the proliferative effect of the UQCRB mutants was significantly regulated by the UQCRB inhibitors terpestacin and A1938. Collectively, these results provide a molecular basis for UQCRB-related biological processes and reveal potential key roles of UQCRB in angiogenesis and mitochondria-mediated metabolic disorders.

  15. A mutation in the mitochondrial protein UQCRB promotes angiogenesis through the generation of mitochondrial reactive oxygen species

    International Nuclear Information System (INIS)

    Chang, Junghwa; Jung, Hye Jin; Jeong, Seung Hun; Kim, Hyoung Kyu; Han, Jin; Kwon, Ho Jeong

    2014-01-01

    Highlights: • We constructed mitochondrial protein UQCRB mutant stable cell lines on the basis of a human case report. • These mutant cell lines exhibit pro-angiogenic activity with enhanced VEGF expression. • Proliferation of mutant cell lines was regulated by UQCRB inhibitors. • UQCRB may have a functional role in angiogenesis. - Abstract: Ubiquinol-cytochrome c reductase binding protein (UQCRB) is one of the subunits of mitochondrial complex III and is a target protein of the natural anti-angiogenic small molecule terpestacin. Previously, the biological role of UQCRB was thought to be limited to the maintenance of complex III. However, the identification and validation of UQCRB as a target protein of terpestacin enabled the role of UQCRB in oxygen sensing and angiogenesis to be elucidated. To explore the biological role of this protein further, UQCRB mutant stable cell lines were generated on the basis of a human case report. We demonstrated that these cell lines exhibited glycolytic and pro-angiogenic activities via mitochondrial reactive oxygen species (mROS)-mediated HIF1 signal transduction. Furthermore, a morphological abnormality in mitochondria was detected in UQCRB mutant stable cell lines. In addition, the proliferative effect of the UQCRB mutants was significantly regulated by the UQCRB inhibitors terpestacin and A1938. Collectively, these results provide a molecular basis for UQCRB-related biological processes and reveal potential key roles of UQCRB in angiogenesis and mitochondria-mediated metabolic disorders

  16. Economic feasibility of promoting species of lower water requirements to improve water condition of lake Urmia using of PES schemes

    International Nuclear Information System (INIS)

    Daneshi, A.; Panahi, M.; Vafakhah, M.

    2016-01-01

    Since agricultural sector is considered as the biggest user of freshwater resources in Iran, one of the major factors of Urmia lake drying might be attributed to unsustainable development of agricultural activities. Therefore, it would be of interest to focus the lake restoration measures on water usage management in agricultural sector. It seems that a program to change cropping pattern based on the use of species with lower water requirements instead of higher water need ones is an effective policy. In this study, we attempted firstly, to propose to farmers change in cropping pattern by replacing the sugar beet, alfalfa, corn and tomato with wheat and barley as a solution. Then, results of the survey have been assessed in economic terms. Area in which the survey has been undertaken is Simineh Rud basin. To collect data, a combined techniques of interview and questionnaires have been used. The results of this study showed that this program has sufficient acceptability to the farmers (in 2014) and in case of having financial support by government, it will have successful implementation. Meanwhile, from technical and economic point of view, implementation of such a program has benefit-cost ratio of 2.12 for wheat and 2.06 for barley. Therefore, based on feasibility of such proposal, allocating required budgets, implementing the proposed plan in all other sub-basins of Urmia lake and paying income deficit caused by change in cropping pattern to farmers may suggested.

  17. Reactive Oxygen Species Generated by NADPH Oxidases Promote Radicle Protrusion and Root Elongation during Rice Seed Germination

    Directory of Open Access Journals (Sweden)

    Wen-Yan Li

    2017-01-01

    Full Text Available Seed germination is a complicated biological process that requires regulation through various enzymatic and non-enzymatic mechanisms. Although it has been recognized that reactive oxygen species (ROS regulate radicle emergence and root elongation in a non-enzymatic manner during dicot seed germination, the role of ROS in monocot seed germination remains unknown. NADPH oxidases (NOXs are the major ROS producers in plants; however, whether and how NOXs regulate rice seed germination through ROS generation remains unclear. Here, we report that diphenyleneiodinium (DPI, a specific NOX inhibitor, potently inhibited embryo and seedling growth—especially that of the radicle and of root elongation—in a dose-dependent manner. Notably, the DPI-mediated inhibition of radicle and root growth could be eliminated by transferring seedlings from DPI to water. Furthermore, ROS production/accumulation during rice seed germination was quantified via histochemistry. Superoxide radicals (O2−, hydrogen peroxide (H2O2 and hydroxyl radicals (•OH accumulated steadily in the coleorhiza, radicle and seedling root of germinating rice seeds. Expression profiles of the nine typical NOX genes were also investigated. According to quantitative PCR, OsNOX5, 7 and 9 were expressed relatively higher. When seeds were incubated in water, OsNOX5 expression progressively increased in the embryo from 12 to 48 h, whereas OsNOX7 and 9 expressions increased from 12 to 24 h and decreased thereafter. As expected, DPI inhibits the expression at predetermined time points for each of these genes. Taken together, these results suggest that ROS produced by NOXs are involved in radicle and root elongation during rice seed germination, and OsNOX5, 7 and 9 could play crucial roles in rice seed germination. These findings will facilitate further studies of the roles of ROS generated by NOXs during seed germination and seedling establishment and also provide valuable information for the

  18. Coexistence of Sarcoidosis and Gouty Arthritis.

    Science.gov (United States)

    Semiz, Hüseyin; Kobak, Senol

    2017-08-21

    Sarcoidosis is an inflammatory disease with unknown cause characterized by non-caseating granuloma formations. It may present with bilateral hilar lymphadenopathy, skin lesions, the involvement of eye and symptoms on the locomotor system. Gouty arthritis is an autoinflammatory disease characterized by hyperuricemia, recurrent arthritis attacks and the deposition of monosodium urate crystals in the joints and the surrounding tissues. We reported the coexistence of sarcoidosis and gouty arthritis in this paper. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Reumatología y Colegio Mexicano de Reumatología. All rights reserved.

  19. Coexisting typical migraine in familial hemiplegic migraine

    DEFF Research Database (Denmark)

    Hansen, Jakob Møller; Thomsen, Lise Lykke; Olesen, Jes

    2010-01-01

    In contrast to patients with migraine with aura (MA) and migraine without aura (MO), most patients with familial hemiplegic migraine (FHM) do not report migraine-like attacks after pharmacologic provocation with glyceryl trinitrate (GTN), a donor of nitric oxide. In the present study, we examined...... patients with FHM without known gene mutations and hypothesized that 1) GTN would cause more migraine-like attacks in patients with FHM compared to controls, and 2) GTN would cause more migraine attacks in patients with FHM with coexisting MA or MO compared to the pure FHM phenotype....

  20. Discovery of the shape coexisting 0+ state in 32Mg

    International Nuclear Information System (INIS)

    Wimmer, Kathrin

    2010-01-01

    The evolution of shell structure in exotic nuclei as a function of proton (Z) and neutron (N) number is currently at the center of many theoretical and experimental investigations. It has been realized that the interaction of the last valence protons and neutrons, in particular the monopole component of the residual interaction between those nucleons, can lead to significant shifts in the single-particle energies, leading to the collapse of classic shell closures and the appearance of new shell gaps. The ''Island of Inversion'' around 32 Mg, which is one of the most studied phenomena in the nuclear chart, is a well known example for such changes in nuclear structure. In this region of neutron-rich nuclei around the magic number N=20 strongly deformed ground states in Ne, Na, and Mg isotopes have been observed. Due to the reduction of the N=20 shell gap quadrupole correlations can enable low-lying deformed 2p-2h intruder states from the fp-shell to compete with spherical normal neutron 0p-0h states of the sd-shell. In this situation the promotion of a neutron pair across the N=20 gap can result in deformed intruder ground states. Consequentially the two competing configurations can lead to the coexistence of spherical and deformed 0 + states in the neutron rich nuclei 30,32 Mg. In this work the shape coexistence in 32 Mg was studied by a two neutron transfer reaction at the REX-ISOLDE facility (CERN). The two neutron transfer reaction with a 30 Mg beam involved for the first time the use of a radioactive tritium target in combination with a radioactive heavy ion beam. Light charged particles emitted from the target were detected and identified by the T-REX particle detector while γ-rays were detected by the MINIBALL Germanium detector array. The shape of the angular distribution of the protons allows to unambiguously determine the angular momentum transfer ΔL of the reaction and thus to identify the 0 + states. The analysis of excitation energies and angular

  1. Biogeochemical and Ecomorphological Niche Segregation of Mediterranean Woody Species along a Local Gradient

    Directory of Open Access Journals (Sweden)

    Enrique G. de la Riva

    2017-07-01

    Full Text Available According with niche theory the species are specialized in different ecological niches, being able to coexist as result of a differential use of resources. In this context, the biogeochemical niche hypothesis proposes that species have an optimal elemental composition which results from the link between the chemical and morphological traits for the optimum plant functioning. Thus, and attending to the limiting similarity concept, different elemental composition and plant structure among co-occurring species may reduce competition, promoting different functional niches. Different functional habits associated with leaf life-span or growth forms are associated with different strategies for resource uptake, which could promote niche partitioning. In the present study, based on the biogeochemical niche concept and the use of resources in different proportions, we have focused on leaf traits (morphological and chemical associated with resource uptake, and explored the niche partitioning among functional habits: leaf life-span (deciduous, evergreen, and semideciduous and growth (tree, shrub, and arborescent-shrub. To this end, we have quantified the hypervolume of the leaf functional trait space (both structure and chemical composition in a sample of 45 Mediterranean woody species from Sierra Morena Mountains (Spain growing along a local soil resource gradient. Our results show consistent variation in functional space for woody communities distributed along the environmental gradient. Thus, communities dominated by deciduous trees with faster growth and a predominant acquisitive strategy were characteristic of bottom forests and showed highest leaf biogeochemical space. While semideciduous shrubs and evergreen (arborescent, trees species, characterized by a conservative strategy, dominated ridge forests and showed smaller functional space. In addition, within each topographical zone or environment type, the foliar biogeochemical niche partitioning

  2. Biogeochemical and Ecomorphological Niche Segregation of Mediterranean Woody Species along a Local Gradient.

    Science.gov (United States)

    de la Riva, Enrique G; Marañón, Teodoro; Violle, Cyrille; Villar, Rafael; Pérez-Ramos, Ignacio M

    2017-01-01

    According with niche theory the species are specialized in different ecological niches, being able to coexist as result of a differential use of resources. In this context, the biogeochemical niche hypothesis proposes that species have an optimal elemental composition which results from the link between the chemical and morphological traits for the optimum plant functioning. Thus, and attending to the limiting similarity concept, different elemental composition and plant structure among co-occurring species may reduce competition, promoting different functional niches. Different functional habits associated with leaf life-span or growth forms are associated with different strategies for resource uptake, which could promote niche partitioning. In the present study, based on the biogeochemical niche concept and the use of resources in different proportions, we have focused on leaf traits (morphological and chemical) associated with resource uptake, and explored the niche partitioning among functional habits: leaf life-span (deciduous, evergreen, and semideciduous) and growth (tree, shrub, and arborescent-shrub). To this end, we have quantified the hypervolume of the leaf functional trait space (both structure and chemical composition) in a sample of 45 Mediterranean woody species from Sierra Morena Mountains (Spain) growing along a local soil resource gradient. Our results show consistent variation in functional space for woody communities distributed along the environmental gradient. Thus, communities dominated by deciduous trees with faster growth and a predominant acquisitive strategy were characteristic of bottom forests and showed highest leaf biogeochemical space. While semideciduous shrubs and evergreen (arborescent, trees) species, characterized by a conservative strategy, dominated ridge forests and showed smaller functional space. In addition, within each topographical zone or environment type, the foliar biogeochemical niche partitioning would underlie the

  3. Native bacterial endophytes promote host growth in a species-specific manner; phytohormone manipulations do not result in common growth responses.

    Directory of Open Access Journals (Sweden)

    Hoang Hoa Long

    Full Text Available BACKGROUND: All plants in nature harbor a diverse community of endophytic bacteria which can positively affect host plant growth. Changes in plant growth frequently reflect alterations in phytohormone homoeostasis by plant-growth-promoting (PGP rhizobacteria which can decrease ethylene (ET levels enzymatically by 1-aminocyclopropane-1-carboxylate (ACC deaminase or produce indole acetic acid (IAA. Whether these common PGP mechanisms work similarly for different plant species has not been rigorously tested. METHODOLOGY/PRINCIPAL FINDINGS: We isolated bacterial endophytes from field-grown Solanum nigrum; characterized PGP traits (ACC deaminase activity, IAA production, phosphate solubilization and seedling colonization; and determined their effects on their host, S. nigrum, as well as on another Solanaceous native plant, Nicotiana attenuata. In S. nigrum, a majority of isolates that promoted root growth were associated with ACC deaminase activity and IAA production. However, in N. attenuata, IAA but not ACC deaminase activity was associated with root growth. Inoculating N. attenuata and S. nigrum with known PGP bacteria from a culture collection (DSMZ reinforced the conclusion that the PGP effects are not highly conserved. CONCLUSIONS/SIGNIFICANCE: We conclude that natural endophytic bacteria with PGP traits do not have general and predictable effects on the growth and fitness of all host plants, although the underlying mechanisms are conserved.

  4. Coexistence of Phases in a Protein Heterodimer

    Science.gov (United States)

    Krokhotin, Andrey; Liwo, Adam; Niemi, Antti J.; Scheraga, Harold A.

    2012-07-01

    A heterodimer consisting of two or more different kinds of proteins can display an enormous number of distinct molecular architectures. The conformational entropy is an essential ingredient in the Helmholtz free energy and, consequently, these heterodimers can have a very complex phase structure. Here, it is proposed that there is a state of proteins, in which the different components of a heterodimer exist in different phases. For this purpose, the structures in the protein data bank (PDB) have been analyzed, with radius of gyration as the order parameter. Two major classes of heterodimers with their protein components coexisting in different phases have been identified. An example is the PDB structure 3DXC. This is a transcriptionally active dimer. One of the components is an isoform of the intra-cellular domain of the Alzheimer-disease related amyloid precursor protein (AICD), and the other is a nuclear multidomain adaptor protein in the Fe65 family. It is concluded from the radius of gyration that neither of the two components in this dimer is in its own collapsed phase, corresponding to a biologically active protein. The UNRES energy function has been utilized to confirm that, if the two components are separated from each other, each of them collapses. The results presented in this work show that heterodimers whose protein components coexist in different phases, can have intriguing physical properties with potentially important biological consequences.

  5. Shape Coexistence In Light Krypton Isotopes

    International Nuclear Information System (INIS)

    Clement, E.; Goergen, A.; Bouchez, E.; Chatillon, A.; Korten, W.; Le Coz, Y.; Theisen, Ch.; Huerstel, A.; Lucas, R.; Wilson, J.N.; Andreoiu, C.; Butler, P.; Herzberg, R.-D.; Iwanicki, J.; Jenkins, D.; Jones, G.; Becker, F.; Gerl, J.; Blank, B.; Hannachi, F.

    2005-01-01

    Shape coexistence in the light krypton isotopes was studied in a series of experiments at GANIL using various experimental techniques. A new low-lying 0+ state, a so-called shape isomer, was found in delayed conversion-electron spectroscopy after fragmentation reactions. The systematics of such low-lying 0+ states suggests that the ground states of the isotopes 78Kr and 76Kr have prolate deformation, while states with prolate and oblate shape are practically degenerate and strongly mixed in 74Kr, and that the oblate configuration becomes the ground state in 72Kr. This scenario was tested in experiments performing low-energy Coulomb excitation of radioactive 76Kr and 74Kr beams from the SPIRAL facility. Both transitional and diagonal electromagnetic matrix elements were extracted from the observed γ-ray yields. The results find the prolate shape for the ground-state bands in 76Kr and 74Kr and an oblate deformation for the excited 2 2 + state in 74Kr, confirming the proposed scenario of shape coexistence

  6. Coexistence of bronchiectasis and rheumatoid arthritis: revisited.

    Science.gov (United States)

    Wilczynska, Maria M; Condliffe, Alison M; McKeon, Damian J

    2013-04-01

    The presence of bronchiectasis (BR) in patients with rheumatoid arthritis (RA) has been recognized for many decades; nevertheless, little research has been undertaken in this area. It is important to recognize that BR coexistent with RA differs from the other types of BR. The purpose of this descriptive review was to delineate the epidemiology, etiology, risk factors, pulmonary function testing, imaging, prognosis and management of concomitant BR and RA. To inform our study we searched the PubMed, EMBASE, CINAHL, and MEDLINE databases, using combinations of the following key words: computed tomography, lung function tests, rheumatoid arthritis, bronchiectasis, biological agents, and interstitial lung disease. The number of published papers covering this topic is limited, but several relevant conclusions can be drawn. Patients with concomitant RA and BR have worse obstructive airways disease, increased susceptibility to recurrent pulmonary infections, faster lung function decline, and higher mortality, compared with subjects with either RA or BR alone. The use of disease-modifying anti-rheumatic drugs (both biological and non-biological) for RA in RA-BR patients imparts a further challenge in managing these patients. Although there are not any published guidelines on the management of coexisting RA-BR, we have attempted to provide such recommendations, based on the literature review and our experience.

  7. Effect of migration in a diffusion model for template coexistence in protocells.

    Science.gov (United States)

    Fontanari, José F; Serva, Maurizio

    2014-03-01

    The compartmentalization of distinct templates in protocells and the exchange of templates between them (migration) are key elements of a modern scenario for prebiotic evolution. Here we use the diffusion approximation of population genetics to study analytically the steady-state properties of such a prebiotic scenario. The coexistence of distinct template types inside a protocell is achieved by a selective pressure at the protocell level (group selection) favoring protocells with a mixed template composition. In the degenerate case, where the templates have the same replication rate, we find that a vanishingly small migration rate suffices to eliminate the segregation effect of random drift and so to promote coexistence. In the nondegenerate case, a small migration rate greatly boosts coexistence as compared with the situation where there is no migration. However, increase of the migration rate beyond a critical value leads to the complete dominance of the more efficient template type (homogeneous regime). In this case, we find a continuous phase transition separating the homogeneous and the coexistence regimes, with the order parameter vanishing linearly with the distance to the transition point.

  8. Coexistence of Reverse Capgras Syndrome, Subjective Double and Cotard Syndrome

    Directory of Open Access Journals (Sweden)

    Azadeh Mashayekhi

    2016-01-01

    Full Text Available Misidentification syndrome is a condition in which the person thinks that familiar persons have been replaced with other one. Coexistence of some types of this syndrome has been reported with other psychiatric syndromes. In this report, we present a 47-year-old married man with coexistence of reverse Capgras and subjective double syndromes with Cotard syndrome. There is no previous report of coexistence of these three forms of delusions in a single case.

  9. Community structure informs species geographic distributions

    KAUST Repository

    Montesinos-Navarro, Alicia; Estrada, Alba; Font, Xavier; Matias, Miguel G.; Meireles, Catarina; Mendoza, Manuel; Honrado, Joao P.; Prasad, Hari D.; Vicente, Joana R.; Early, Regan

    2018-01-01

    spatial resolution. However, survival of individuals is determined by processes that happen at small spatial scales. The relative abundance of coexisting species (i.e. 'community structure') reflects assembly processes occurring at small scales

  10. The challenges of managing coexistent disorders with phenylketonuria

    DEFF Research Database (Denmark)

    MacDonald, A; Ahring, K; Almeida, M F

    2015-01-01

    INTRODUCTION: The few published case reports of co-existent disease with phenylketonuria (PKU) are mainly genetic and familial conditions from consanguineous marriages. The clinical and demographic features of 30 subjects with PKU and co-existent conditions were described in this multi-centre, re......INTRODUCTION: The few published case reports of co-existent disease with phenylketonuria (PKU) are mainly genetic and familial conditions from consanguineous marriages. The clinical and demographic features of 30 subjects with PKU and co-existent conditions were described in this multi...

  11. Costs of coexistence along a gradient of competitor densities: an experiment with arvicoline rodents.

    Science.gov (United States)

    Eccard, Jana A; Ylönen, Hannu

    2007-01-01

    1. Costs of coexistence for species with indirect resource competition usually increase monotonically with competitor numbers. Very little is known though about the shape of the cost function for species with direct interference competition. 2. Here we report the results of an experiment with two vole species in artificial coexistence in large enclosures, where density of the dominant competitor species (Microtus agrestis) was manipulated. Experimental populations of the subordinate vole species (Clethrionomys glareolus) were composed of same aged individuals to study distribution of costs of coexistence with a dominant species within an age-cohort. 3. Survival and space use decreased gradually with increasing field vole numbers. Thus, responses to interference competition in our system appeared to be similar as expected from resource competition. The total number of breeders was stable. Reproductive characteristics such as the timing of breeding, and the litter size were not affected. In the single species enclosures a proportion of surviving individuals were not able to establish a breeding territory against stronger conspecifics. Under competition with heterospecifics such nonbreeders suffered high mortality, whereas the breeders survived. 4. Combined interference of dominant conspecifics and heterospecifics probably increased the frequency of aggressive interactions, social stress and mortality for the weaker individuals within a homogeneous age cohort of the subordinate competitor population. 5. Our results suggest, that in open systems where bank voles are outcompeted over the breeding season by faster reproducing field voles, animals able to establish a territory may be able to withstand competitor pressure, while nonbreeding bank vole individuals are forced to emigrate to suboptimal forest habitats.

  12. Limits on new forces coexisting with electromagnetism

    International Nuclear Information System (INIS)

    Kloor, H.; Fischbach, E.; Talmadge, C.; Greene, G.L.

    1994-01-01

    We consider the limits arising from different electromagnetic systems on the existence of a possible new electromagnetic analogue of the fifth force. Although such a force may have no intrinsic connection to electromagnetism (or gravity), its effects could be manifested through various anomalies in electromagnetic systems, for appropriate values of the coupling strength and range. Our work generalizes that of Bartlett and Loegl (who considered the case of a massive vector field coexisting with massless electrodynamics) to encompass a broad class of phenomenological interactions mediated by both scalar and vector exchanges. By combining data from both gravitational and electromagnetic systems, one can eventually set limits on a new force whose range λ extends from the subatomic scale (λ∼10 -15 m) to the astrophysical scale (λ∼10 12 m)

  13. Coexistence of giant cell fibroblastoma and encephalocele.

    Science.gov (United States)

    Afroz, Nishat; Shamim, Nida; Jain, Anshu; Soni, Mayank

    2014-04-11

    Giant cell fibroblastoma (GCF) is a rare soft tissue tumour that occurs almost exclusively in children younger than 10 years of age and is mostly located in the superficial soft tissues of the back and thighs. We present a rare case of GCF with encephalocele in a 1.5-year-old boy who presented with a swelling in the occipital area of the scalp since birth. CT scan suggested encephalocele without any suspicion of a mass lesion. On histopathology, an ill-defined proliferation of fibroblasts in a heavily collagenised and focally myxoid stroma was seen containing numerous multinucleated cells having a floret-like appearance along with mature glial tissue bordering a cystic space. Immunohistochemically, the stromal cells were positive for both, vimentin (diffuse) and CD34 (focal) thereby confirming the histological diagnosis of GCF. This case highlights the unusual coexistence of GCF with congenital defects and its histogenetic resemblance to dermatofibrosarcoma protuberans.

  14. Coexisting principles and logics of elder care

    DEFF Research Database (Denmark)

    Dahl, Hanne Marlene; Eskelinen, Leena; Boll Hansen, Eigil

    2015-01-01

    Healthy and active ageing has become an ideal in Western societies. In the Nordic countries, this ideal has been supported through a policy of help to self-help in elder care since the 1980s. However, reforms inspired by New Public Management (NPM) have introduced a new policy principle of consumer......-oriented service that stresses the wishes and priorities of older people. We have studied how these two principles are applied by care workers in Denmark. Is one principle or logic replacing the other, or do they coexist? Do they create tensions between professional knowledge and the autonomy of older people......? Using neo-institutional theory and feminist care theory, we analysed the articulation of the two policy principles in interviews and their logics in observations in four local authorities. We conclude that help to self-help is the dominant principle, that it is deeply entrenched in the identity...

  15. Coexistence of pheochromocytoma with uncommon vascular lesions

    Directory of Open Access Journals (Sweden)

    Sunil Kumar Kota

    2012-01-01

    Full Text Available Background: Pheochromocytoma/paragangliomas have been described to be associated with rare vascular abnormalities like renal artery stenosis. Coexistence of physiologically significant renal artery lesions is a compounding factor that alters management and prognosis of pheochromocytoma patients. Apart from individual case reports, data on such association in Indian population is not available. The aim of this study is to find the nature and prevalence of associated vascular abnormalities. Materials and Methods: From 1990 to 2010, a total of 50 patients were diagnosed with pheochromocytoma/paragangliomas. Hospital charts of these patients were reviewed retrospectively to identify those with unusual vascular abnormalities. Available literature was also reviewed. Results: Of the 50 patients with pheochromocytoma, 7 (14% had coexisting vascular lesions including renal artery stenosis in 4, aortoarteritis in 1, aortic aneurysm in 1 and inferior vena cava thrombosis in 1. Pheochromocytoma was adrenal in 42 and extra adrenal in 8. Laparoscopic adrenalectomy was done in the patients. One patient with renal artery stenosis due to intimal fibrosis was subjected to percutaneous balloon angioplasty; the other three improved after adrenalectomy and lysis of fibrous adhesive bands. The patient with aortoarteritos was treated with oral steroids. Inferior vena cava thrombosis was reversed with anticoagulants. The patient with abdominal aortic aneurysm was advised for annual follow-up on account of its size of 4.5 cm and asymptomatic presentation. Conclusion: There are multiple mechanisms that can lead to renal artery stenosis and other vascular abnormalities in a case of pheochromocytoma. A high index of suspicion is necessary to enable both entities to be diagnosed preoperatively and allow proper planning of surgical therapy. Incomplete diagnosis may lead to persistent hypertension postoperatively in a case of associated renal artery stenosis.

  16. Hypotonic stress promotes ATP release, reactive oxygen species production and cell proliferation via TRPV4 activation in rheumatoid arthritis rat synovial fibroblasts

    International Nuclear Information System (INIS)

    Hu, Fen; Hui, Zhenhai; Wei, Wei; Yang, Jianyu; Chen, Ziyuan; Guo, Bu; Xing, Fulin; Zhang, Xinzheng; Pan, Leiting; Xu, Jingjun

    2017-01-01

    Rheumatoid arthritis (RA) is a chronic and systemic autoimmune-disease with complex and unclear etiology. Hypotonicity of synovial fluid is a typical characteristic of RA, which may play pivotal roles in RA pathogenesis. In this work, we studied the responses of RA synovial fibroblasts to hypotonic stress in vitro and further explored the underlying mechanisms. Data showed that hyposmotic solutions significantly triggered increases in cytosolic calcium concentration ([Ca 2+ ] c ) of synoviocytes. Subsequently, it caused rapid release of ATP, as well as remarkable production of intracellular reactive oxygen species (ROS). Meanwhile, hypotonic stimulus promoted the proliferation of synovial fibroblasts. These effects were almost abolished by calcium-free buffer and significantly inhibited by gadolinium (III) chloride (a mechanosensitive Ca 2+ channel blocker) and ruthenium red (a transient receptor potential vanilloid 4 (TRPV4) blocker). 4α-phorbol 12,13-didecanoate, a specific agonist of TRPV4, also mimicked hypotonic shock-induced responses shown above. In contrast, voltage-gated channel inhibitors verapamil and nifedipine had little influences on these responses. Furthermore, RT-PCR and western blotting evidently detected TRPV4 expression at mRNA and protein level in isolated synoviocytes. Taken together, our results indicated that hypotonic stimulus resulted in ATP release, ROS production, and cell proliferation depending on Ca 2+ entry through activation of TRPV4 channel in synoviocytes. - Highlights: • Hypotonic stress evokes Ca 2+ entry in rheumatoid arthritis synovial fibroblasts. • Hypotonic stress induces rapid ATP release and ROS production in synoviocytes. • Hypotonic stimulation promotes the proliferation of synovial fibroblasts. • TRPV4 controls hypotonic-induced responses in synoviocytes.

  17. Finding your mate at a cocktail party: frequency separation promotes auditory stream segregation of concurrent voices in multi-species frog choruses.

    Directory of Open Access Journals (Sweden)

    Vivek Nityananda

    Full Text Available Vocal communication in crowded social environments is a difficult problem for both humans and nonhuman animals. Yet many important social behaviors require listeners to detect, recognize, and discriminate among signals in a complex acoustic milieu comprising the overlapping signals of multiple individuals, often of multiple species. Humans exploit a relatively small number of acoustic cues to segregate overlapping voices (as well as other mixtures of concurrent sounds, like polyphonic music. By comparison, we know little about how nonhuman animals are adapted to solve similar communication problems. One important cue enabling source segregation in human speech communication is that of frequency separation between concurrent voices: differences in frequency promote perceptual segregation of overlapping voices into separate "auditory streams" that can be followed through time. In this study, we show that frequency separation (ΔF also enables frogs to segregate concurrent vocalizations, such as those routinely encountered in mixed-species breeding choruses. We presented female gray treefrogs (Hyla chrysoscelis with a pulsed target signal (simulating an attractive conspecific call in the presence of a continuous stream of distractor pulses (simulating an overlapping, unattractive heterospecific call. When the ΔF between target and distractor was small (e.g., ≤3 semitones, females exhibited low levels of responsiveness, indicating a failure to recognize the target as an attractive signal when the distractor had a similar frequency. Subjects became increasingly more responsive to the target, as indicated by shorter latencies for phonotaxis, as the ΔF between target and distractor increased (e.g., ΔF = 6-12 semitones. These results support the conclusion that gray treefrogs, like humans, can exploit frequency separation as a perceptual cue to segregate concurrent voices in noisy social environments. The ability of these frogs to segregate

  18. The challenges of managing coexistent disorders with phenylketonuria: 30 cases.

    Science.gov (United States)

    MacDonald, A; Ahring, K; Almeida, M F; Belanger-Quintana, A; Blau, N; Burlina, A; Cleary, M; Coskum, T; Dokoupil, K; Evans, S; Feillet, F; Giżewska, M; Gokmen Ozel, H; Lotz-Havla, A S; Kamieńska, E; Maillot, F; Lammardo, A M; Muntau, A C; Puchwein-Schwepcke, A; Robert, M; Rocha, J C; Santra, S; Skeath, R; Strączek, K; Trefz, F K; van Dam, E; van Rijn, M; van Spronsen, F; Vijay, S

    2015-12-01

    The few published case reports of co-existent disease with phenylketonuria (PKU) are mainly genetic and familial conditions from consanguineous marriages. The clinical and demographic features of 30 subjects with PKU and co-existent conditions were described in this multi-centre, retrospective cohort study. Diagnostic age of PKU and co-existent condition, treatment regimen, and impact of co-existent condition on blood phenylalanine (Phe) control and PKU management were reported. 30 patients (11 males and 19 females), with PKU and a co-existent condition, current median age of 14 years (range 0.4 to 40 years) from 13 treatment centres from Europe and Turkey were described. There were 21 co-existent conditions with PKU; 9 were autoimmune; 6 gastrointestinal, 3 chromosomal abnormalities, and 3 inherited conditions. There were only 5 cases of parental consanguinity. Some patients required conflicting diet therapy (n=5), nutritional support (n=7) and 5 children had feeding problems. There was delayed diagnosis of co-existent conditions (n=3); delayed treatment of PKU (n=1) and amenorrhea associated with Grave's disease that masked a PKU pregnancy for 12 weeks. Co-existent conditions adversely affected blood Phe control in 47% (n=14) of patients. Some co-existent conditions increased the complexity of disease management and increased management burden for patients and caregivers. Occurrence of co-existent disease is not uncommon in patients with PKU and so investigation for co-existent disorders when the clinical history is not completely consistent with PKU is essential. Integrating care of a second condition with PKU management is challenging. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. The Lion King and the Hyaena Queen: large carnivore interactions and coexistence.

    Science.gov (United States)

    Périquet, Stéphanie; Fritz, Hervé; Revilla, Eloy

    2015-11-01

    Interactions among species, which range from competition to facilitation, have profound effects on ecosystem functioning. Large carnivores are of particular importance in shaping community structure since they are at the top of the food chain, and many efforts are made to conserve such keystone species. Despite this, the mechanisms of carnivore interactions are far from understood, yet they are key to enabling or hindering their coexistence and hence are highly relevant for their conservation. The goal of this review is thus to provide detailed information on the extents of competition and facilitation between large carnivores and their impact in shaping their life histories. Here, we use the example of spotted hyaenas (Crocuta crocuta) and lions (Panthera leo) and provide a comprehensive knowledge of their interactions based on meta-analyses from available literature (148 publications). Despite their strong potential for both exploitation and interference competition (range and diet overlap, intraguild predation and kleptoparasitism), we underline some mechanisms facilitating their coexistence (different prey-age selection and scavenging opportunities). We stress the fact that prey abundance is key to their coexistence and that hyaenas forming very large groups in rich ecosystems could have a negative impact on lions. We show that the coexistence of spotted hyaenas and lions is a complex balance between competition and facilitation, and that prey availability within the ecosystem determines which predator is dominant. However, there are still many gaps in our knowledge such as the spatio-temporal dynamics of their interactions. As both species' survival becomes increasingly dependent on protected areas, where their densities can be high, it is critical to understand their interactions to inform both reintroduction programs and protected area management. © 2014 Cambridge Philosophical Society.

  20. Critical Reflection on the Role of Education as a Catalyst of Peace-Building and Peaceful Coexistence

    Science.gov (United States)

    Agnihotri, Seema

    2017-01-01

    Human being since its evolution is continuously struggling to combat inherent prowess of violence and conflict as a part of biological species which is falling in an ambivalent position in the ecosystem. It was realized long years back that only peaceful coexistence can ensure the prolonged journey of humanity without any turmoil. But this…

  1. Transitions and coexistence along a grazing gradient in the Eurasian steppe

    Science.gov (United States)

    Ren, Haiyan; Taube, Friedelm; Zhang, Yingjun; Bai, Yongfei; Hu, Shuijin

    2017-04-01

    Ecological resilience theory has often been applied to explain species coexistence and range condition assessment of various community states and to explicate the dynamics of ecosystems. Grazing is a primary disturbance that can alter rangeland resilience by causing hard-to-reverse transitions in grasslands. Yet, how grazing affects the coexistence of plant functional group (PFG) and transition remains unclear. We conducted a six-year grazing experiment in a typical steppe of Inner Mongolia, using seven grazing intensities (0, 1.5, 3.0, 4.5, 6.0, 7.5 and 9.0 sheep/ hectare) and two grazing systems (i.e. a continuous annual grazing as in the traditional grazing system, and a mixed grazing system combining grazing and haymaking), to examine grazing effects on plant functional group shifts and species coexistence in the semi-arid grassland system. Our results indicate that the relative richness of dominant bunchgrasses and forbs had a compensatory coexistence at all grazing intensities, and the richness of rhizomatous grasses fluctuated but was persistent. The relative productivity of dominant bunchgrasses and rhizomatous grasses had compensatory interactions with grazing intensity and grazing system. Dominant bunchgrasses and rhizomatous grasses resist grazing effects by using their dominant species functional traits: high specific leaf area and low leaf nitrogen content. Our results suggest that: 1. Stabilizing mechanisms beyond grazing management are more important in determining plant functional group coexistence and ecological resilience. 2. Plant functional group composition is more important in influencing ecosystem functioning than diversity. 3. Ecosystem resilience at a given level is related to the biomass of dominant PFG, which is determined by a balanced shift between dominant species biomass. The relatively even ecosystem resilience along the grazing gradient is attributed to the compensatory interactions of dominant species in their biomass variations

  2. Association between promoter methylation of MLH1 and MSH2 and reactive oxygen species in oligozoospermic men-A pilot study.

    Science.gov (United States)

    Gunes, S; Agarwal, A; Henkel, R; Mahmutoglu, A M; Sharma, R; Esteves, S C; Aljowair, A; Emirzeoglu, D; Alkhani, A; Pelegrini, L; Joumah, A; Sabanegh, E

    2018-04-01

    MLH1 and MSH2 are important genes for DNA mismatch repair and crossing over during meiosis and are implicated in male infertility. Therefore, the methylation patterns of the DNA mismatch repair genes MLH1 and MSH2 in oligozoospermic males were investigated. Ten oligozoospermic patients and 29 normozoospermic donors were analysed. Methylation profiles of the MLH1 and MSH2 promotors were analysed. In addition, sperm motility and seminal reactive oxygen species (ROS) were recorded. Receiver operating characteristic (ROC) analysis was conducted to determine the accuracy of the DNA methylation status of MLH1 and MSH2 to distinguish between oligozoospermic and normozoospermic men. In oligozoospermic men, MLH1 was significantly (p = .0013) more methylated compared to normozoospermic men. Additionally, there was a significant positive association (r = .384; p = .0159) between seminal ROS levels and MLH1 methylation. Contrary, no association between MSH2 methylation and oligozoospermia was found. ROC curve analysis for methylation status of MLH1 was significant (p = .0275) with an area under the curve of 61.1%, a sensitivity of 22.2% and a specificity of 100.0%. This pilot study indicates oligozoospermic patients have more methylation of MLH1 than normozoospermic patients. Whether hypermethylation of the MLH1 promoter plays a role in repairing relevant mismatches of sperm DNA strands in idiopathic oligozoospermia warrants further investigation. © 2017 Blackwell Verlag GmbH.

  3. Native plant growth promoting bacteria Bacillus thuringiensis and mixed or individual mycorrhizal species improved drought tolerance and oxidative metabolism in Lavandula dentata plants.

    Science.gov (United States)

    Armada, E; Probanza, A; Roldán, A; Azcón, R

    2016-03-15

    This study evaluates the responses of Lavandula dentata under drought conditions to the inoculation with single autochthonous arbuscular mycorrhizal (AM) fungus (five fungal strains) or with their mixture and the effects of these inocula with a native Bacillus thuringiensis (endophytic bacteria). These microorganisms were drought tolerant and in general, increased plant growth and nutrition. Particularly, the AM fungal mixture and B. thuringiensis maximized plant biomass and compensated drought stress as values of antioxidant activities [superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase APX)] shown. The AMF-bacteria interactions highly reduced the plant oxidative damage of lipids [malondialdehyde (MDA)] and increased the mycorrhizal development (mainly arbuscular formation representative of symbiotic functionality). These microbial interactions explain the highest potential of dually inoculated plants to tolerate drought stress. B. thuringiensis "in vitro" under osmotic stress does not reduce its PGPB (plant growth promoting bacteria) abilities as indole acetic acid (IAA) and ACC deaminase production and phosphate solubilization indicating its capacity to improve plant growth under stress conditions. Each one of the autochthonous fungal strains maintained their particular interaction with B. thuringiensis reflecting the diversity, intrinsic abilities and inherent compatibility of these microorganisms. In general, autochthonous AM fungal species and particularly their mixture with B. thuringiensis demonstrated their potential for protecting plants against drought and helping plants to thrive in semiarid ecosystems. Copyright © 2015 Elsevier GmbH. All rights reserved.

  4. Coexistence of gout and rheumatoid arthritis in Nairobi, Kenya ...

    African Journals Online (AJOL)

    Background: There is a widespread belief that gout and RA rarely coexist in the same patient. Given that there is an excess burden of cardiovascular disease in patients with RA, this is compounded by hyperuricemia. The purpose of this study was to describe the clinical profiles of patients with coexistent gout and ...

  5. Coexistence of hyperon and π condensation in neutron stars

    International Nuclear Information System (INIS)

    Isshiki, Akinori

    2000-01-01

    We consider the coexistence of hyperon and π condensation in neutron stars. The coexistence phase may occur because of the strong ΛΣπ coupling. Hyperon can appear under π condensation, because short range repulsion reduce the π-baryon p wave attraction. The system approaches the Fermi gas because of this reduction. (author)

  6. Geometry of coexistence in the interacting boson model

    International Nuclear Information System (INIS)

    Van Isacker, P.; Frank, A.; Vargas, C.E.

    2004-01-01

    The Interacting Boson Model (IBM) with configuration mixing is applied to describe the phenomenon of coexistence in nuclei. The analysis suggests that the IBM with configuration mixing, used in conjunction with a (matrix) coherent-state method, may be a reliable tool for the study of geometric aspects of shape coexistence in nuclei

  7. Coexisting Disorders and Academic Achievement among Children with ADHD

    Science.gov (United States)

    Barnard-Brak, Lucy; Sulak, Tracey N.; Fearon, Danielle D.

    2011-01-01

    Objective: ADHD is a commonly diagnosed neuropsychological disorder among school-aged children with reported high rates of coexisting or comorbid disorders. As ADHD has been associated with academic underachievement, the current study examines this association in view of the presence of coexisting disorders. The purpose of the current study is to…

  8. The challenges of managing coexistent disorders with phenylketonuria : 30 cases

    NARCIS (Netherlands)

    MacDonald, A.; Ahring, K.; Almeida, M. F.; Belanger-Quintana, A.; Blau, N.; Burlina, A.; Cleary, M.; Coskum, T.; Dokoupil, K.; Evans, S.; Feillet, F.; Gizewska, M.; Ozel, H. Gokmen; Lotz-Havla, A. S.; Kamienska, E.; Maillot, F.; Lammardo, A. M.; Muntau, A. C.; Puchwein-Schwepcke, A.; Robert, M.; Rocha, J. C.; Santra, S.; Skeath, R.; Straczek, K.; Trefz, F. K.; van Dam, E.; van Rijn, M.; van Spronsen, F.; Vijay, S.

    2015-01-01

    Introduction: The few published case reports of co-existent disease with phenylketonuria (PKU) are mainly genetic and familial conditions from consanguineous marriages. The clinical and demographic features of 30 subjects with PKU and co-existent conditions were described in this multi-centre,

  9. Quantum mechanical analogy for solving a competitive coexistence model in ecology

    International Nuclear Information System (INIS)

    Wio, H.S.; Kuperman, M.N.; Haeften, B. von

    1994-07-01

    We have studied an ecological system of three species: a strong and a weak one, competing for a single food resource, modelled as a reaction-diffusion process. An exact analytical solution has been found through a quantum mechanical analogy. Such solution indicates that in certain situations the classical results on extinction and coexistence of Lotka-Volterra type equations are no longer valid, essentially, as a consequence of the weak species mobility. A stability analysis of this solution against changes in different parameters has been carried out. (author). 19 refs, 5 figs

  10. How directional mobility affects coexistence in rock-paper-scissors models

    Science.gov (United States)

    Avelino, P. P.; Bazeia, D.; Losano, L.; Menezes, J.; de Oliveira, B. F.; Santos, M. A.

    2018-03-01

    This work deals with a system of three distinct species that changes in time under the presence of mobility, selection, and reproduction, as in the popular rock-paper-scissors game. The novelty of the current study is the modification of the mobility rule to the case of directional mobility, in which the species move following the direction associated to a larger (averaged) number density of selection targets in the surrounding neighborhood. Directional mobility can be used to simulate eyes that see or a nose that smells, and we show how it may contribute to reduce the probability of coexistence.

  11. Evaluation of the basic concepts of approaches for the coexistence of nuclear energy and people/local community

    International Nuclear Information System (INIS)

    Kondo, Shunsuke; Kuroki, Shinichi; Nakagiri, Yuko

    2007-01-01

    In November 2007, the Policy Evaluation Committee compiled the report, which evaluated the basic concepts of approaches to the coexistence of nuclear energy and people/local community, specified in the Framework for Nuclear Energy Policy. The report states that the 'concerned administrative bodies are carrying out measures related to the coexistence of nuclear energy and people/local communities in line with these basic concept' and summarizes fifteen proposals conductive to the betterment and improvement of these measures, which were classified as 1) secure transparency and promotion of mutual understanding with the public, 2) development and enrichment of learning opportunities and public participation, 3) relationship between the government and local governments and 4) coexistence with local residents. The Japan Atomic Energy Commission (JAEC) considers this report to be reasonable. This article presented an overview of this activity. (T. Tanaka)

  12. Syringomyelia coexisting with guillain-barre syndrome.

    Science.gov (United States)

    Kim, Hee-Sang; Yun, Dong Hwan; Chon, Jinmann; Lee, Jong Eon; Park, Min Ho; Han, Yoo Jin

    2013-10-01

    Guillain-Barre syndrome (GBS) and syringomyelia are diseases of different entities. GBS is an acute post-infectious autoimmune disease which is mediated by autoantibodies against the myelin of peripheral nerves. Syringomyelia is a chronic disease characterized by a cavity extending longitudinally inside the spinal cord. A 67-year-old man is being hospitalized due to severe numbness and ascending weakness in all limbs. On neurological examination, the motor power of all limbs are decreased and show absence of deep tendon reflexes (DTRs). The patient is being diagnosed with GBS on the basis of the acute clinical course, nerve conduction studies of segmental demyelinating polyneuropathy, and a finding of albuminocytologic dissociation in the cerebrospinal fluid. The patient is presented with a new set of symptoms thereafter, which composes of sensory changes in the upper extremities, the urinary dysfunction including frequency and residual urine, spastic bilateral lower extremities, and increased reflexes of the knee and the biceps at follow-up examinations. The spinal magnetic resonance imaging in the sagittal section revealed a syrinx cavity between the fifth cervical and the first thoracic vertebral segment in the cord. The somatosensory evoked potential show sensory pathway defects between both the brachial plexus and the brain stem. Thus, this patient is being diagnosed with both GBS and syringomyelia. We report a case of symptomatic syringomyelia coexisting with GBS. Since the GBS is presented with a progressive muscle weakness and reduced DTRs, the muscle weakness and stiffness in the extremities suggests a concurrent syringomyelia might be easily overlooked.

  13. Toxic amebic colitis coexisting with intestinal tuberculosis.

    Science.gov (United States)

    Park, S. C.; Jeon, H. M.; Kim, J. S.; Kim, W. W.; Kim, K. W.; Oh, S. T.; Kim, E. K.; Chang, S. K.; Lee, E. J.

    2000-01-01

    A patient with a fulminant amebic colitis coexisting with intestinal tuberculosis had a sudden onset of crampy abdominal pain, mucoid diarrhea, anorexia, fever and vomiting with signs of positive peritoneal irritation. Fulminant amebic colitis occurring together with intestinal tuberculosis is an uncommon event and may present an interesting patho-etiological relationship. The diagnosis was proven by histopathologic examination of resected specimen. Subtotal colectomy including segmental resection of ileum, about 80 cm in length, followed by exteriorization of both ends, was performed in an emergency basis. Despite all measures, the patient died on the sixth postoperative day. The exact relationship of fulminant amebic colitis and intestinal tuberculosis is speculative but the possibility of a cause and effect relationship exists. Fulminant amebic colitis may readily be confused with other types of inflammatory bowel disease, such as idiopathic ulcerative colitis, Crohn's disease, perforated diverticulitis and appendicitis with perforation. This report draws attention to the resurgence of tuberculosis and amebiasis in Korea, and the need for the high degree of caution required to detect it. PMID:11194200

  14. Shape coexistence and evolution in 98Sr

    Science.gov (United States)

    Park, J.; Garnsworthy, A. B.; Krücken, R.; Andreoiu, C.; Ball, G. C.; Bender, P. C.; Chester, A.; Close, A.; Finlay, P.; Garrett, P. E.; Glister, J.; Hackman, G.; Hadinia, B.; Leach, K. G.; Rand, E. T.; Sjue, S.; Starosta, K.; Svensson, C. E.; Tardiff, E.

    2016-01-01

    Shape coexistence between the strongly deformed ground state and the weakly deformed 02+ state in 98Sr has been a major topic of interest due to the energy difference of 215 keV, which is the smallest in all even-even nuclei. The electric monopole transition strength ρ2(E 0 ) is an important quantity that can relate the deformation difference and the shape mixing between the two 0+ states, which are admixtures of the vibrational (S) and the rotational (D) states in a simple mixing model. In a β -decay spectroscopy experiment, the experimental ρ2(E 0 ) was measured. A value of 0.053(5) is consistent with the previous measurement and was combined with known electric quadrupole transition strengths B (E 2 ) in calculations of a two-state mixing model. Based on a systematic study on neighboring Kr, Zr, and Mo isotopes, the mixing of the 0+ and 2+ states in 98Sr was determined to be 8.6% and 1.3%, respectively, corresponding to deformation parameters βD=0.38 (1 ) and βS=-0.23 (2 ) . These parameters reproduce experimental transition strengths well except for the 41+→21+ transition, which suggests a smaller D-band deformation for J ≥4 .

  15. Management of coexisting Hodgkin's disease and pregnancy

    International Nuclear Information System (INIS)

    Nisce, L.Z.; Tome, M.A.; He, S.; Lee, B.J. III; Kutcher, G.J.

    1986-01-01

    The management of pregnant women with active Hodgkin's disease (H.D.) should be individualized depending on the stage, the presence of infradiaphragmatic involvement, and age of gestation. Seventeen women aged 16-31 years with coexisting H.D. and pregnancy were followed between 1969 and 1982. H.D. was diagnosed during pregnancy in 15 patients and two became pregnant while on treatment. Seven women whose pregnancies were allowed to proceed uninterrupted were irradiated to supradiaphragmatic sites to doses of 1500-2000 rad during the second or third trimester; all had full term spontaneous normal deliveries and normal infants. Fetal doses ranged from 2-50 rad. Two patients treated with Vinblastine throughout three pregnancies delivered normal full term infants. Pregnancy was interrupted in six patients at 6-20 weeks of gestation for various reasons. In spite of several months delay in initiation of definitive therapy, the outcome of H.D. was not adversely affected in the majority of uninterrupted pregnancies as evidenced by long term disease-free survivals of 6-11 years in four of seven patients who were irradiated; the children now aged 6-11 years are also alive and reported normal

  16. Ultraviolet B preconditioning enhances the hair growth-promoting effects of adipose-derived stem cells via generation of reactive oxygen species.

    Science.gov (United States)

    Jeong, Yun-Mi; Sung, Young Kwan; Kim, Wang-Kyun; Kim, Ji Hye; Kwack, Mi Hee; Yoon, Insoo; Kim, Dae-Duk; Sung, Jong-Hyuk

    2013-01-01

    Hypoxia induces the survival and regenerative potential of adipose-derived stem cells (ASCs), but there are tremendous needs to find alternative methods for ASC preconditioning. Therefore, this work investigated: (1) the ability of low-dose ultraviolet B (UVB) radiation to stimulate the survival, migration, and tube-forming activity of ASCs in vitro; (2) the ability of UVB preconditioning to enhance the hair growth-promoting capacity of ASCs in vivo; and (3) the mechanism of action for ASC stimulation by UVB. Although high-dose UVB decreased the proliferation of ASCs, low-dose (10 or 20 mJ/cm(2)) treatment increased their survival, migration, and tube-forming activity. In addition, low-dose UVB upregulated the expression of ASC-derived growth factors, and a culture medium conditioned by UVB-irradiated ASCs increased the proliferation of dermal papilla and outer root sheet cells. Notably, injection of UVB-preconditioned ASCs into C(3)H/HeN mice significantly induced the telogen-to-anagen transition and increased new hair weight in vivo. UVB treatment significantly increased the generation of reactive oxygen species (ROS) in cultured ASCs, and inhibition of ROS generation by diphenyleneiodonium chloride (DPI) significantly attenuated UVB-induced ASC stimulation. Furthermore, NADPH oxidase 4 (Nox4) expression was induced in ASCs by UVB irradiation, and Nox4 silencing by small interfering RNA, like DPI, significantly reduced UVB-induced ROS generation. These results suggest that the primary involvement of ROS generation in UVB-mediated ASC stimulation occurs via the Nox4 enzyme. This is the first indication that a low dose of UVB radiation and/or the control of ROS generation could potentially be incorporated into a novel ASC preconditioning method for hair regeneration.

  17. Cyclic public goods games: Compensated coexistence among mutual cheaters stabilized by optimized penalty taxation

    Science.gov (United States)

    Griffin, Christopher; Belmonte, Andrew

    2017-05-01

    We study the problem of stabilized coexistence in a three-species public goods game in which each species simultaneously contributes to one public good while freeloading off another public good ("cheating"). The proportional population growth is governed by an appropriately modified replicator equation, depending on the returns from the public goods and the cost. We show that the replicator dynamic has at most one interior unstable fixed point and that the population becomes dominated by a single species. We then show that by applying an externally imposed penalty, or "tax" on success can stabilize the interior fixed point, allowing for the symbiotic coexistence of all species. We show that the interior fixed point is the point of globally minimal total population growth in both the taxed and untaxed cases. We then formulate an optimal taxation problem and show that it admits a quasilinearization, resulting in novel necessary conditions for the optimal control. In particular, the optimal control problem governing the tax rate must solve a certain second-order ordinary differential equation.

  18. Coexistence for an Almost Periodic Predator-Prey Model with Intermittent Predation Driven by Discontinuous Prey Dispersal

    Directory of Open Access Journals (Sweden)

    Yantao Luo

    2017-01-01

    Full Text Available An almost periodic predator-prey model with intermittent predation and prey discontinuous dispersal is studied in this paper, which differs from the classical continuous and impulsive dispersal predator-prey models. The intermittent predation behavior of the predator species only happens in the channels between two patches where the discontinuous migration movement of the prey species occurs. Using analytic approaches and comparison theorems of the impulsive differential equations, sufficient criteria on the boundedness, permanence, and coexistence for this system are established. Finally, numerical simulations demonstrate that, for an intermittent predator-prey model, both the intermittent predation and intrinsic growth rates of the prey and predator species can greatly impact the permanence, extinction, and coexistence of the population.

  19. Limited diffusive fluxes of substrate facilitate coexistence of two competing bacterial strains

    DEFF Research Database (Denmark)

    Dechesne, Arnaud; Or, D.; Smets, Barth F.

    2008-01-01

    . It has been proposed, but never unambiguously experimentally tested, that a low substrate diffusive flux would impact bacterial diversity, by promoting the coexistence between slow-growing bacteria and their potentially faster-growing competitors. We used a simple experimental system, based on a Petri...... dish and a perforated Teflon((R)) membrane to control diffusive fluxes of substrate (benzoate) whilst permitting direct observation of bacterial colonies. The system was inoculated with prescribed strains of Pseudomonas, whose growth was quantified by microscopic monitoring of the fluorescent proteins...

  20. Contemporary Multi religious and Peaceful Coexistence of Islam in ...

    African Journals Online (AJOL)

    Contemporary Multi religious and Peaceful Coexistence of Islam in Nigeria's State. ... in a multicultural society tend to lead to the violation of universal human rights, ... religio-phobic, religio-centric and terrorist behaviours among adherents in ...

  1. The dilemma of over and under nutrition coexistence among ...

    African Journals Online (AJOL)

    The dilemma of over and under nutrition coexistence among western Kenya children. ... that might have existed in this target group, particularly the school age children. ... It is also known that childhood obesity and/or overweight have positive ...

  2. A Kolmogorov-type competition model with multiple coexistence states and its applications to plant competition for sunlight

    Science.gov (United States)

    Just, Winfried; Nevai, Andrew L.

    2008-12-01

    It is demonstrated that a Kolmogorov-type competition model featuring species allocation and gain functions can possess multiple coexistence statesE Two examples are constructed: one in which the two competing species possess rectangular allocation functions but distinct gain functions, and the other in which one species has a rectangular allocation function, the second species has a bi-rectangular allocation function, and the two species share a common gain function. In both examples, it is shown that the species nullclines may intersect multiple times within the interior of the first quadrant, thus creating both locally stable and unstable equilibrium points. These results have important applications in the study of plant competition for sunlight, in which the allocation functions describe the vertical placement of leaves for two competing species, and the gain functions represent rates of photosynthesis performed by leaves at different heights when shaded by overlying leaves belonging to either species.

  3. Good fences: the importance of setting boundaries for peaceful coexistence.

    Directory of Open Access Journals (Sweden)

    Alex Rutherford

    Full Text Available We consider the conditions of peace and violence among ethnic groups, testing a theory designed to predict the locations of violence and interventions that can promote peace. Characterizing the model's success in predicting peace requires examples where peace prevails despite diversity. Switzerland is recognized as a country of peace, stability and prosperity. This is surprising because of its linguistic and religious diversity that in other parts of the world lead to conflict and violence. Here we analyze how peaceful stability is maintained. Our analysis shows that peace does not depend on integrated coexistence, but rather on well defined topographical and political boundaries separating groups, allowing for partial autonomy within a single country. In Switzerland, mountains and lakes are an important part of the boundaries between sharply defined linguistic areas. Political canton and circle (sub-canton boundaries often separate religious groups. Where such boundaries do not appear to be sufficient, we find that specific aspects of the population distribution guarantee either sufficient separation or sufficient mixing to inhibit intergroup violence according to the quantitative theory of conflict. In exactly one region, a porous mountain range does not adequately separate linguistic groups and that region has experienced significant violent conflict, leading to the recent creation of the canton of Jura. Our analysis supports the hypothesis that violence between groups can be inhibited by physical and political boundaries. A similar analysis of the area of the former Yugoslavia shows that during widespread ethnic violence existing political boundaries did not coincide with the boundaries of distinct groups, but peace prevailed in specific areas where they did coincide. The success of peace in Switzerland may serve as a model to resolve conflict in other ethnically diverse countries and regions of the world.

  4. Magnetic nesting and co-existence of ferromagnetism and superconductivity

    International Nuclear Information System (INIS)

    Elesin, V.F.; Kapaev, V.V.; Kopaev, Yu.V.

    2004-01-01

    In the case of providing for the magnetic nesting conditions of the electron spin dispersion law the co-existence of ferromagnetism and superconductivity is possible by any high magnetization. The co-existence of ferromagnetism and superconductivity in the layered cuprate compounds of the RuSr 2 GdCu 2 O 8 -type is explained on this basis, wherein due to the nonstrict provision of the magnetic nesting condition there exists the finite but sufficiently high critical magnetization [ru

  5. The costs of coexistence on farms in Germany

    DEFF Research Database (Denmark)

    Punt, Maarten J.; Venus, Thomas J.; Wesseler, Justus H H

    2017-01-01

    for farmers in their cultivation decisions, and therefore it is important to measure these costs. In this article, we investigate the costs of different coexistence measures for farmers in Germany. Currently, GM crop cultivation is outlawed in Germany, but there was a short period from 2005-2008 when...... that there are important differences in farm characteristics and overall landscape configuration that influence the costs or burden of coexistence measures....

  6. Species co-occurrence affects the trophic interactions of two juvenile reef shark species in tropical lagoon nurseries in Moorea (French Polynesia).

    Science.gov (United States)

    Matich, Philip; Kiszka, Jeremy J; Mourier, Johann; Planes, Serge; Heithaus, Michael R

    2017-06-01

    Food web structure is shaped by interactions within and across trophic levels. As such, understanding how the presence and absence of predators, prey, and competitors affect species foraging patterns is important for predicting the consequences of changes in species abundances, distributions, and behaviors. Here, we used plasma δ 13 C and δ 15 N values from juvenile blacktip reef sharks (Carcharhinus melanopterus) and juvenile sicklefin lemon sharks (Negaprion acutidens) to investigate how species co-occurrence affects their trophic interactions in littoral waters of Moorea, French Polynesia. Co-occurrence led to isotopic niche partitioning among sharks within nurseries, with significant increases in δ 15 N values among sicklefin lemon sharks, and significant decreases in δ 15 N among blacktip reef sharks. Niche segregation likely promotes coexistence of these two predators during early years of growth and development, but data do not suggest coexistence affects life history traits, such as body size, body condition, and ontogenetic niche shifts. Plasticity in trophic niches among juvenile blacktip reef sharks and sicklefin lemon sharks also suggests these predators are able to account for changes in community structure, resource availability, and intra-guild competition, and may fill similar functional roles in the absence of the other species, which is important as environmental change and human impacts persist in coral reef ecosystems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Promoter sequence of 3-phosphoglycerate kinase gene 1 of lactic acid-producing fungus rhizopus oryzae and a method of expressing a gene of interest in fungal species

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Johnway [Richland, WA; Skeen, Rodney S [Pendleton, OR

    2002-10-15

    The present invention provides the promoter clone discovery of phosphoglycerate kinase gene 1 of a lactic acid-producing filamentous fungal strain, Rhizopus oryzae. The isolated promoter can constitutively regulate gene expression under various carbohydrate conditions. In addition, the present invention also provides a design of an integration vector for the transformation of a foreign gene in Rhizopus oryzae.

  8. Promoter sequence of 3-phosphoglycerate kinase gene 2 of lactic acid-producing fungus rhizopus oryzae and a method of expressing a gene of interest in fungal species

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Johnway [Richland, WA; Skeen, Rodney S [Pendleton, OR

    2003-03-04

    The present invention provides the promoter clone discovery of phosphoglycerate kinase gene 2 of a lactic acid-producing filamentous fungal strain, Rhizopus oryzae. The isolated promoter can constitutively regulate gene expression under various carbohydrate conditions. In addition, the present invention also provides a design of an integration vector for the transformation of a foreign gene in Rhizopus oryzae.

  9. In the absence of a "landscape of fear": How lions, hyenas, and cheetahs coexist.

    Science.gov (United States)

    Swanson, Alexandra; Arnold, Todd; Kosmala, Margaret; Forester, James; Packer, Craig

    2016-12-01

    Aggression by top predators can create a "landscape of fear" in which subordinate predators restrict their activity to low-risk areas or times of day. At large spatial or temporal scales, this can result in the costly loss of access to resources. However, fine-scale reactive avoidance may minimize the risk of aggressive encounters for subordinate predators while maintaining access to resources, thereby providing a mechanism for coexistence. We investigated fine-scale spatiotemporal avoidance in a guild of African predators characterized by intense interference competition. Vulnerable to food stealing and direct killing, cheetahs are expected to avoid both larger predators; hyenas are expected to avoid lions. We deployed a grid of 225 camera traps across 1,125 km 2 in Serengeti National Park, Tanzania, to evaluate concurrent patterns of habitat use by lions, hyenas, cheetahs, and their primary prey. We used hurdle models to evaluate whether smaller species avoided areas preferred by larger species, and we used time-to-event models to evaluate fine-scale temporal avoidance in the hours immediately surrounding top predator activity. We found no evidence of long-term displacement of subordinate species, even at fine spatial scales. Instead, hyenas and cheetahs were positively associated with lions except in areas with exceptionally high lion use. Hyenas and lions appeared to actively track each, while cheetahs appear to maintain long-term access to sites with high lion use by actively avoiding those areas just in the hours immediately following lion activity. Our results suggest that cheetahs are able to use patches of preferred habitat by avoiding lions on a moment-to-moment basis. Such fine-scale temporal avoidance is likely to be less costly than long-term avoidance of preferred areas: This may help explain why cheetahs are able to coexist with lions despite high rates of lion-inflicted mortality, and highlights reactive avoidance as a general mechanism for

  10. Coexistence of two distinct Sulfurospirillum populations respiring tetrachloroethene - genomic and kinetic considerations

    DEFF Research Database (Denmark)

    Buttet, Géraldine Florence; Murray, Alexandra Marie; Goris, Tobias

    2018-01-01

    Two anaerobic bacterial consortia, each harboring a distinct Sulfurospirillum population, were derived from a ten year old consortium, SL2, previously characterized for the stepwise dechlorination of tetrachloroethene (PCE) to cis-dichloroethene (cis-DCE) via accumulation of trichloroethene (TCE......). Population SL2-1 dechlorinated PCE to TCE exclusively, while SL2-2 produced cis-DCE from PCE without substantial TCE accumulation. The reasons explaining the long-term coexistence of the populations were investigated. Genome sequencing revealed a novel Sulfurospirillum species, designated 'Candidatus...

  11. Incubation period and immune function: A comparative field study among coexisting birds

    Science.gov (United States)

    Palacios, M.G.; Martin, T.E.

    2006-01-01

    Developmental periods are integral components of life history strategies that can have important fitness consequences and vary enormously among organisms. However, the selection pressures and mechanisms causing variation in length of developmental periods are poorly understood. Particularly puzzling are prolonged developmental periods, because their selective advantage is unclear. Here we tested the hypotheses that immune function is stronger in species that are attacked at a higher rate by parasites and that prolonged embryonic development allows the development of this stronger immune system. Through a comparative field study among 12 coexisting passerine bird species, we show that species with higher blood parasite prevalence mounted stronger cellular immune responses than species with lower prevalence. These results provide support for the hypothesis that species facing greater selection pressure from parasites invest more in immune function. However, species with longer incubation periods mounted weaker cellular immune responses than species with shorter periods. Therefore, cellular immune responses do not support the hypothesis that longer development time enhances immunocompentence. Future studies should assess other components of the immune system and test alternative causes of variation in incubation periods among bird species. ?? Springer-Verlag 2005.

  12. Shape coexistence of light, even A mercury isotopes

    International Nuclear Information System (INIS)

    Cole, J.D.

    1978-01-01

    The results of the studies of the decay of thallium isotopes establish the coexistence and crossing of two bands in the mercury isotopes. The two bands are built on states of different deformation. The band built upon the ground state has an associated small negative β value (oblate shape) while the second band has a large positive β value (prolate shape). The band heads for the deformed bands in the 184 186 188 Hg isotopes are established as 0 + levels at 375.2, 523.8, and 824.5 keV respectively. A comparison between the experimental results and the predictions of calculations based upon the coexistence of two different nuclear deformations has been made. The presence of two different deformations as described by two minima in the nuclear potential energy curve is termed ''shape coexistence.'' The good agreement of the calculations with the experimental results adds further support to the coexistence interpretation. The coexistence and crossing of two bands of different deformation explains the unusual behavior of the yrast level spacing that is referred to as 'backbending' when discussing moment of inertia versus rotational frequency plots based on the yrast levels. The studies of the 186 188 Pt levels have established the lower members of the ground state band and of a rotation-alignment band. The experimental results confirm the rotation-alignment explanation of backbending in the platinum cases discussed. (Auth.)

  13. Considerations for Managing Agricultural Co-Existence between Transgenic and Non-Transgenic Cultivars of Outcrossing Perennial Forage Plants in Dairy Pastures

    Directory of Open Access Journals (Sweden)

    Kevin F. Smith

    2016-11-01

    Full Text Available Many of the major forage species used in agriculture are outcrossing and rely on the exchange of pollen between individuals for reproduction; this includes the major species used for dairy production in grazing systems: perennial ryegrass (Lolium perenne L. and white clover (Trifolium repens L.. Cultivars of these species have been co-existing since contrasting cultivars were developed using plant breeding, but the consequences and need for strategies to manage co-existence have been made more prominent with the advent of genetic modification. Recent technological developments have seen the experimental evaluation of genetically modified (GM white clover and perennial ryegrass, although there is no current commercial growing of GM cultivars of these species. Co-existence frameworks already exist for two major cross-pollinated grain crops (canola and maize in Europe, and for alfalfa (Medicago sativa L. in the US, so many of the principles that the industry has developed for co-existence in these crops such as detection techniques, segregation, and agronomic management provide lessons and guidelines for outcrossing forage species, that are discussed in this paper.

  14. Beyond peaceful coexistence the emergence of space, time and quantum

    CERN Document Server

    2016-01-01

    Beyond Peaceful Coexistence: The Emergence of Space, Time and Quantum brings together leading academics in mathematics and physics to address going beyond the 'peaceful coexistence' of space-time descriptions (local and continuous ones) and quantum events (discrete and non-commutative ones). Formidable challenges waiting beyond the Standard Model require a new semantic consistency within the theories in order to build new ways of understanding, working and relating to them. The original A. Shimony meaning of the peaceful coexistence (the collapse postulate and non-locality) appear to be just the tip of the iceberg in relation to more serious fundamental issues across physics as a whole.Chapters in this book present perspectives on emergent, discrete, geometrodynamic and topological approaches, as well as a new interpretative spectrum of quantum theories after Copenhagen, discrete time theories, time-less approaches and 'super-fluid' pictures of space-time.As well as stimulating further research among establis...

  15. Thermal expansion of coexistence of ferromagnetism and superconductivity

    International Nuclear Information System (INIS)

    Hatayama, Nobukuni; Konno, Rikio

    2010-01-01

    The temperature dependence of thermal expansion of coexistence of ferromag-netism and superconductivity below the superconducting transition temperature T cu of a majority spin conduction band is investigated. Majority spin and minority spin superconducting gaps exist in the coexistent state. We assume that the Curie temperature is much larger than the superconducting transition temperatures. The free energy that Linder et al. [Phys. Rev. B76, 054511 (2007)] derived is used. The thermal expansion of coexistence of ferromagnetism and superconductivity is derived by the application of the method of Takahashi and Nakano [J. Phys.: Condens. Matter 18, 521 (2006)]. We find that we have the anomalies of the thermal expansion in the vicinity of the superconducting transition temperatures.

  16. Interdisciplinary and Cross-Cultural Perspectives on Explanatory Coexistence.

    Science.gov (United States)

    Watson-Jones, Rachel E; Busch, Justin T A; Legare, Cristine H

    2015-10-01

    Natural and supernatural explanations are used to interpret the same events in a number of predictable and universal ways. Yet little is known about how variation in diverse cultural ecologies influences how people integrate natural and supernatural explanations. Here, we examine explanatory coexistence in three existentially arousing domains of human thought: illness, death, and human origins using qualitative data from interviews conducted in Tanna, Vanuatu. Vanuatu, a Melanesian archipelago, provides a cultural context ideal for examining variation in explanatory coexistence due to the lack of industrialization and the relatively recent introduction of Christianity and Western education. We argue for the integration of interdisciplinary methodologies from cognitive science and anthropology to inform research on explanatory coexistence. Copyright © 2015 Cognitive Science Society, Inc.

  17. Endometrial Adenocarcinoma and Mucocele of the Appendix: An Unusual Coexistence

    Directory of Open Access Journals (Sweden)

    Ioannis Kalogiannidis

    2013-01-01

    Full Text Available Appendiceal mucocele is a rare clinical entity, which is however quite often associated with mucinous ovarian tumor. The coexistence of mucinous cystadenoma of the appendix and endometrial adenocarcinoma has not been reported before. A 49-year-old woman presented to our clinic with postmenopausal bleeding and no other symptom. Endometrial biopsy revealed endometrial adenocarcinoma of endometrioid type (grade I. Preoperative CT scanning revealed an appendiceal mucocele, and a colonoscopy confirmed the diagnosis. The patient underwent total abdominal hysterectomy with bilateral salpingo-oophorectomy and appendectomy. The final histopathological examination showed a mucinous cystadenoma of the appendix and confirmed the diagnosis of endometrioid endometrial adenocarcinoma. The coexistence of appendiceal mucocele and female genital tract pathology is rare. However, gynecologists should keep a high level of suspicion for such possible coexistence. Both the diagnostic approach and the therapeutic management should be multidisciplinary, most importantly with the involvement of general surgeons.

  18. Coexistence of uniquely ergodic subsystems of interval mapping

    International Nuclear Information System (INIS)

    Ye Xiangdong.

    1991-10-01

    The purpose of this paper is to show that uniquely ergodic subsystems of interval mapping also coexist in the same way as minimal sets do. To do this we give some notations in section 2. In section 3 we define D-function of a uniquely ergodic system and show its basic properties. We prove the coexistence of uniquely ergodic subsystems of interval mapping in section 4. Lastly we give the examples of uniquely ergodic systems with given D-functions in section 5. 27 refs

  19. Coexistence of morphea and granuloma annulare: a rare case report

    Directory of Open Access Journals (Sweden)

    Şenay Ağırgöl

    2017-11-01

    Full Text Available ABSTRACT CONTEXT: Localized scleroderma (morphea is characterized by fibrosis of skin and subcutaneous tissue. Granuloma annulare is a relatively common disease that is characterized by dermal papules and arciform plaques. CASE REPORT: Here, we present the case of a 42-year-old woman who developed granuloma annulare on the dorsum of her feet and abdominal region, and morphea on the anterior side of her lower limbs. We also discuss the etiological and pathogenetic processes that may cause the rare coexistence of these two diseases. CONCLUSION: Only a few cases in the literature have described coexistence of morphea and granuloma annulare.

  20. Shape coexistence and phase transitions in the platinum isotopes

    International Nuclear Information System (INIS)

    Morales, Irving O.; Frank, Alejandro; Vargas, Carlos E.; Isacker, P. Van

    2008-01-01

    The matrix coherent-state approach of the interacting boson model with configuration mixing is used to study the geometry of the platinum isotopes. With a parameter set determined in previous studies, it is found that the absolute minimum of the potential for the Pt isotopes evolves from spherical to oblate and finally to prolate shapes when the neutron number decreases from N=126 (semi-magic) to N=104 (mid-shell). Shape coexistence is found in the isotopes 182,184,186,188 Pt. A phase diagram is constructed that shows the coexistence region as a function of the number of bosons and the strength of the mixing parameter

  1. Training in Values to Strengthen Social and Civic Coexistence

    Directory of Open Access Journals (Sweden)

    Yajaira del Valle Cadenas Terán

    2017-02-01

    Full Text Available The purpose of this study is to present significantly values training to strengthen social and citizen considering that the coexistence of human beings has not been entirely easy, but so far they have managed to relate many of their problems with how to relate and interact with the environment, especially with the social environment. This study was conducted with a literature review which is the basis for targeted strengthening coexistence and citizenship therefore falls from a descriptive research training documentary. In conclusion, the importance of the subject since doors for values, dialogues, reflections, quality of life, among others that reflect the actions of teachers based on principles axiological open.

  2. Posttraumatic stress disorder and posttraumatic growth coexistence and the risk factors in Wenchuan earthquake survivors.

    Science.gov (United States)

    Wu, Zhibin; Xu, Jiuping; Sui, Yan

    2016-03-30

    Various studies have assessed the negative and/or positive changes in the aftermath of traumatic events. Yet few of these have addressed the factors associated with the coexistence of both negative and positive changes after a devastating earthquake. The aim of this study is to assess the relationship between the negative and positive changes and elucidate the risk factors of such changes one year after Wenchuan earthquake. A total of 2080 survivors from 19 counties participated in a self-report questionnaire survey which included the posttraumatic stress disorder (PTSD) Check list-Civilian, the posttraumatic growth PTG Inventory (PTGI). The prevalence of PTSD and moderate PTG was found to be 40.1% (95% CI [37.9% 42.3%]) and 51.1% (95% CI [48.9% 53.3%]). The PTSD and moderate PTG coexistence was 19.6% (95% CI [17.8% 21.4%]). PTSD symptom severity was significantly positively associated with the PTG score. Middle aged groups (31-40 and 41-50 years old, OR=2.323, 95% CI [1.059, 5.095] and OR=2.410, 95% CI [1.090, 5.329] respectively), those with lower income levels (OR=8.019, 95% CI [2.421, 26.558]), those living in temporary house (OR=1.946, 95% CI [1.280, 2.956]), and those who had had less social support (OR=1.109, 95% CI [1.076, 1.143]) had a significantly higher possibility for the presence of PTSD and moderate PTG coexistence. The results indicated the widespread positive changes in earthquake survivors. Better income levels and living conditions and higher social support were suggested to promote PTG in those with PTSD. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  3. Establishment Success of Coexisting Native and Exotic Trees Under an Experimental Gradient of Irradiance and Soil Moisture

    Science.gov (United States)

    González-Muñoz, Noelia; Castro-Díez, Pilar; Fierro-Brunnenmeister, Natalia

    2011-10-01

    The exotic trees Ailanthus altissima, Robinia pseudoacacia, Acer negundo and Elaeagnus angustifolia coexist with the native trees Fraxinus angustifolia and Ulmus minor in river banks of central Spain. Similarly, the exotic trees Acacia dealbata and Eucalyptus globulus co-occur with the natives Quercus pyrenaica and Pinus pinaster in Northwest Spain. We aimed to identify the environmental conditions that favour or hamper the establishment success of these species. In spring 2008, seeds of the studied species were sown under an experimental gradient of light (100, 65, 35, 7% of full sunlight) combined with three levels of soil moisture (mean soil water potential = -0.97, -1.52 and -1.77 MPa.). During the first growing season we monitored seed emergence and seedling survival. We found that the effect of light on the establishment success was stronger than the effect of soil moisture. Both exotic and native species of central Spain showed a good performance under high light, A. negundo being the most shade tolerant . Water shortage diminished E. angustifolia and A. altissima success. Among NW Spain species, A. dealbata and P. pinaster were found to be potential competitors for colonizing high-irradiance scenarios, while Q. pyrenaica and E. globulus were more successful under moderate shade. High soil moisture favoured E. globulus but not A. dealbata establishment. These results contribute to understand some of the factors controlling for spatial segregation between coexisting native and exotic tree species, and can help to take decisions orientated to the control and management of these exotic species.

  4. Patterns of temporal and enemy niche use by a community of leaf cone moths (Caloptilia) coexisting on maples (Acer) as revealed by metabarcoding.

    Science.gov (United States)

    Nakadai, Ryosuke; Kawakita, Atsushi

    2017-06-01

    The diversity of herbivorous insects is often considered a function of host plant diversity. However, recent research has uncovered many examples of closely related herbivores using the same host plant(s), suggesting that partitioning of host plants is not the only mechanism generating diversity. Herbivores sharing hosts may utilize different parts of the same plant, but such resource partitioning is often not apparent; hence, the factors that allow closely related herbivores to coexist are still largely undetermined. We examined whether partitioning of phenology or natural enemies may explain the coexistence of leaf cone moths (Caloptilia; Gracillariidae) associated with maples (Acer; Sapindaceae). Larval activity of 10 sympatric Caloptilia species found on nine maple species was monitored every 2-3 weeks for a total of 13 sampling events, and an exhaustive search for internal parasitoid wasps was conducted using high-throughput sequencing. Blocking primers were used to facilitate the detection of wasp larvae inside moth tissue. We found considerable phenological overlap among Caloptilia species, with two clear peaks in July and September-October. Coexisting Caloptilia species also had largely overlapping parasitoid communities; a total of 13 chalcid and ichneumon wasp species attacked Caloptilia in a nonspecific fashion at an overall parasitism rate of 46.4%. Although coexistence may be facilitated by factors not accounted for in this study, it appears that niche partitioning is not necessary for closely related herbivores to stably coexist on shared hosts. Co-occurrence without resource partitioning may provide an additional axis along which herbivorous insects attain increased species richness. © 2017 John Wiley & Sons Ltd.

  5. Coexistence of continuous variable QKD with intense DWDM classical channels

    International Nuclear Information System (INIS)

    Kumar, Rupesh; Qin, Hao; Alléaume, Romain

    2015-01-01

    We demonstrate experimentally the feasibility of continuous variable quantum key distribution (CV-QKD) in dense-wavelength-division multiplexing networks (DWDM), where QKD will typically have to coexist with several co-propagating (forward or backward) C-band classical channels whose launch power is around 0 dBm. We have conducted experimental tests of the coexistence of CV-QKD multiplexed with an intense classical channel, for different input powers and different DWDM wavelengths. Over a 25 km fiber, a CV-QKD operated over the 1530.12 nm channel can tolerate the noise arising from up to 11.5 dBm classical channel at 1550.12 nm in the forward direction (9.7 dBm in backward). A positive key rate (0.49 kbits s −1 ) can be obtained at 75 km with classical channel power of respectively −3 and −9 dBm in forward and backward. Based on these measurements, we have also simulated the excess noise and optimized channel allocation for the integration of CV-QKD in some access networks. We have, for example, shown that CV-QKD could coexist with five pairs of channels (with nominal input powers: 2 dBm forward and 1 dBm backward) over a 25 km WDM-PON network. The obtained results demonstrate the outstanding capacity of CV-QKD to coexist with classical signals of realistic intensity in optical networks. (paper)

  6. Coexistence of coeliac disease and type 1 diabetes

    OpenAIRE

    Szaflarska-Popławska, Anna

    2014-01-01

    There is a selective review of the literature concerning the coexistence of coeliac disease and type 1 diabetes mellitus. This review focuses on the principles of serological tests towards coeliac disease in patients with type 1 diabetes mellitus and metabolic control measures as a result of a gluten-free diet.

  7. Hemorrhagic fever with renal syndrome and coexisting hantavirus pulmonary syndrome

    Directory of Open Access Journals (Sweden)

    Young Min Hong

    2012-06-01

    Full Text Available Hemorrhagic fever with renal syndrome (HFRS is an acute viral disease with fever, hemorrhage and renal failure caused by hantavirus infection. Hantavirus induces HFRS or hantavirus pulmonary syndrome (HPS. HPS progression to a life-threatening pulmonary disease is found primarily in the USA and very rarely in South Korea. Here, we report a case of HFRS and coexisting HPS.

  8. 78 FR 65960 - Enhancing Agricultural Coexistence; Request for Public Input

    Science.gov (United States)

    2013-11-04

    ... the USDA South Building, 14th Street and Independence Avenue SW., Washington, DC. Normal reading room.... agriculture increases, so does the importance of managing issues that affect agricultural coexistence, such as... DEPARTMENT OF AGRICULTURE Office of the Secretary [Docket No. APHIS-2013-0047] Enhancing...

  9. On the coexistence of the magnetic phases in chromium alloys

    DEFF Research Database (Denmark)

    Lebech, Bente; Mikke, K.

    1969-01-01

    Detailed neutron diffraction investigations have been performed on Cr-Re alloys in order to explain the several observations in Cr alloys of the coexistence of a commensurable and an oscillatory magnetic phase. It is concluded that the individual magnetic phases probably occur in separate domains....

  10. Coexistence of GMO production, labeling policies, and strategic firm interaction

    NARCIS (Netherlands)

    Venus, Thomas Johann

    2017-01-01

    This dissertation analyzes the market effects of the coexistence of genetically modified organism (GMO) and conventional production, labeling policies, and strategic firm interactions through vertical product differentiation. Although we focus on GMOs, the applied frameworks can be adopted and

  11. Interference Mitigation for Coexistence of Heterogeneous Ultra-Wideband Systems

    Directory of Open Access Journals (Sweden)

    Wu Haitao

    2006-01-01

    Full Text Available Two ultra-wideband (UWB specifications, that is, direct-sequence (DS UWB and multiband-orthogonal frequency division multiplexing (MB-OFDM UWB, have been proposed as the candidates of the IEEE 802.15.3a, competing for the standard of high-speed wireless personal area networks (WPAN. Due to the withdrawal of the standardization process, the two heterogeneous UWB technologies will coexist in the future commercial market. In this paper, we investigate the mutual interference of such coexistence scenarios by physical layer Monte Carlo simulations. The results reveal that the coexistence severely degrades the performance of both UWB systems. Moreover, such interference is asymmetric due to the heterogeneity of the two systems. Therefore, we propose the goodput-oriented utility-based transmit power control (GUTPC algorithm for interference mitigation. The feasible condition and the convergence property of GUTPC are investigated, and the choice of the coefficients is discussed for fairness and efficiency. Numerical results demonstrate that GUTPC improves the goodput of the coexisting systems effectively and fairly with saved power.

  12. Practices that support coexistence: A survey of Alfalfa growers

    Science.gov (United States)

    The alfalfa industry has worked hard to foster the coexistence of genetically-engineered (GE) and conventional alfalfa production by developing a set of best management practices that aim to limit adventitious-presence (AP) of GE traits in conventional seed. The general goal is to minimize transgene...

  13. [School coexistence and learning in adolescence from a gender perspective].

    Science.gov (United States)

    Díaz-Aguado Jalón, María José; Martín Seoane, Gema

    2011-04-01

    This article reviews recent research about academic learning and school coexistence in adolescence from a gender perspective. It focuses on the research developed by the Preventive Psychology research group (UCM), specially the results from the Spanish National Study of School Coexistence using a sample of 22,247 secondary school students. Research shows that girls are overrepresented in positive indicators whereas boys are in negative indicators, not only in academic adjustment but also in school coexistence. Girls' better academic achievement can be explained by their higher tendency to overcome sexism: they identify with traditional masculinity values (such as success orientation) without giving up traditional femininity values (such as empathy). Based on this, the following conclusions are reached: 1) to extend the advantages of equality also to men; 2) to emphasize that sharing academic contexts and activities is necessary but sufficient to construct equality; and lastly, 3) to improve school coexistence, it is necessary to adopt a integrative gender approach to prevent any kind of violence, including violence against women.

  14. Beyond Coexistence: Toward a More Reflective Religious Pluralism

    Science.gov (United States)

    Rosenblith, Suzanne

    2008-01-01

    If a pluralistic democratic state such as the United States wishes to move beyond coexistence and toward a more reflective religious pluralism, then public schools must take epistemic issues seriously. Taking a cue from multicultural education, many have called for including the study of religion from a cultural perspective. I argue instead that,…

  15. Energy density functional analysis of shape coexistence in 44S

    International Nuclear Information System (INIS)

    Li, Z. P.; Yao, J. M.; Vretenar, D.; Nikšić, T.; Meng, J.

    2012-01-01

    The structure of low-energy collective states in the neutron-rich nucleus 44 S is analyzed using a microscopic collective Hamiltonian model based on energy density functionals (EDFs). The calculated triaxial energy map, low-energy spectrum and corresponding probability distributions indicate a coexistence of prolate and oblate shapes in this nucleus.

  16. Synchronization in Coupled Oscillators with Two Coexisting Attractors

    International Nuclear Information System (INIS)

    Han-Han, Zhu; Jun-Zhong, Yang

    2008-01-01

    Dynamics in coupled Duffing oscillators with two coexisting symmetrical attractors is investigated. For a pair of Duffing oscillators coupled linearly, the transition to the synchronization generally consists of two steps: Firstly, the two oscillators have to jump onto a same attractor, then they reach synchronization similarly to coupled monostable oscillators. The transition scenarios to the synchronization observed are strongly dependent on initial conditions. (general)

  17. Hinges of Correlation: Spatial Devices of Social Coexistence

    DEFF Research Database (Denmark)

    Lunde Nielsen, Espen

    2015-01-01

    This project investigates the coexistence of and the correlation between the inhabitants within my apartment building, using artistic practices and my own lived experience. These everyday spaces form the primary interface between the individual and the larger social entity of the city. Consciously...

  18. Possible coexistence of antiferromagnetism and superconductivity in the Hubbard model

    International Nuclear Information System (INIS)

    Su Zhaobin; Dong Jinming; Yu Lu; Shen Juelian

    1988-01-01

    The Hubbard model in the nearly half-filled case was studied in the mean field approximation using the effective Hamiltonian approach. Both antiferromagnetic order parameter and condensation of singlet pairs were considered. In certain parameter ranges the coexistence of antiferromagnetism and superconductivity is energetically favourable. Relevance to the high temperature superconductivity and other theoretical approaches is also discussed. (author). 10 refs, 3 figs

  19. Phase coexistence and line tension in ternary lipid systems

    NARCIS (Netherlands)

    Idema, T.; Leeuwen, van J.M.J.; Storm, C.

    2009-01-01

    The ternary system consisting of cholesterol, a saturated lipid, and an unsaturated one exhibits a rich phase behavior with multiple phase coexistence regimes. Remarkably, phase separation even occurs when each of the three binary systems consisting of two of these components is a uniform mixture.

  20. Coexisting Situs Inversus Totalis and Immune Thrombocytopenic Purpura.

    Science.gov (United States)

    Gundogdu, Kemal; Altintoprak, Fatih; Uzunoğlu, Mustafa Yener; Dikicier, Enis; Zengin, İsmail; Yağmurkaya, Orhan

    2016-01-01

    Situs inversus totalis is a rare congenital abnormality with mirror symmetry of mediastinal and abdominal organs. Immune thrombocytopenic purpura is an autoimmune disease with destruction of thrombocytes. This paper is presentation of surgical approach to a case with coexistence of these two conditions.

  1. Coexisting Situs Inversus Totalis and Immune Thrombocytopenic Purpura

    Directory of Open Access Journals (Sweden)

    Kemal Gundogdu

    2016-01-01

    Full Text Available Situs inversus totalis is a rare congenital abnormality with mirror symmetry of mediastinal and abdominal organs. Immune thrombocytopenic purpura is an autoimmune disease with destruction of thrombocytes. This paper is presentation of surgical approach to a case with coexistence of these two conditions.

  2. Tunable two-phase coexistence in half-doped manganites

    Indian Academy of Sciences (India)

    Our recent work on half-doped manganites builds on those ideas to explain our data showing continuously tunable phase coexistence of FM and AFM states. Macroscopic hysteresis across transitions is often used to assert their first-order nature, and this has also been done in the case of half-doped manganites [6]. Kuwa-.

  3. Advanced Cancer Of The Cervix Coexisting With Multiple Fibroids In ...

    African Journals Online (AJOL)

    A case of a 47 year old nulliparous woman with advanced cervical cancer coexisting with uterine fibroid is presented. The nulliparity and the presence of Fibroids presented diagnostic challenges especially because epidemiologically the factors present are not commonly associated. Diagnosis was assisted by a thorough ...

  4. Enhancer-promoter interference and its prevention in transgenic plants

    Science.gov (United States)

    Transcriptional enhancer elements have been shown to override the specificity of nearby promoters in a position- and orientation-independent manner. This is problematic when multiple enhancers/promoters co-exist within a single transgenic construct as it has the potential to cause the mis-expressio...

  5. Differences in growth trajectory and strategy of two sympatric congeneric species in an Indonesian floodplain forest.

    Science.gov (United States)

    Yamada, Toshihiro; Ngakan, Oka Putu; Suzuki, Eizi

    2005-01-01

    Whole-plant development trajectories and sapling leaf displays were compared for two sympatric congeneric species, Pterospermum diversifolium and P. javanicum, in a tropical floodplain forest in East Kalimantan, Indonesia. We assessed their growth strategies and developed hypotheses for their coexistence within the community. Pterospermum diversifolium retains a monoaxial growth habit that promotes quick stem elongation; thus, it is taller when branches are initiated than is P. javanicum. The species differed significantly in height growth and total crown expansion per unit increment of biomass: monoaxial P. diversifolium saplings devote more effort to stem elongation, whereas branched P. javanicum saplings devote more effort to branch expansion. Monoaxial P. diversifolium sustained more severe self-shading than P. javanicum. The sapling growth strategy of P. diversifolium appears to be dynamic, emphasizing the opportunistic use of light following a disturbance, whereas that of P. javanicum appears to be static, optimizing leaf display for current light conditions. The advantages of these strategies depend on context, and the two species may coexist within a community by adopting different regeneration niches based on differing understory light conditions: P. diversifolium is favored over P. javanicum at high light levels, but the opposite is true at low light levels.

  6. Significance of Coexisting Mutations on Determination of the Degree of Isoniazid Resistance in Mycobacterium tuberculosis Strains.

    Science.gov (United States)

    Karunaratne, Galbokka Hewage Roshanthi Eranga; Wijesundera, Sandhya Sulochana; Vidanagama, Dhammika; Adikaram, Chamila Priyangani; Perera, Jennifer

    2018-04-23

    The emergence and spread of drug-resistant tuberculosis (TB) pose a threat to TB control in Sri Lanka. Isoniazid (INH) is a key element of the first-line anti-TB treatment regimen. Resistance to INH is mainly associated with point mutations in katG, inhA, and ahpC genes. The objective of this study was to determine mutations of these three genes in INH-resistant Mycobacterium tuberculosis (MTb) strains in Sri Lanka. Complete nucleotide sequence of the three genes was amplified by polymerase chain reaction and subjected to DNA sequencing. Point mutations in the katG gene were identified in 93% isolates, of which the majority (78.6%) were at codon 315. Mutations at codons 212 and 293 of the katG gene have not been reported previously. Novel mutations were recognized in the promoter region of the inhA gene (C deletion at -34), fabG1 gene (codon 27), and ahpC gene (codon 39). Single S315T mutation in the katG gene led to a high level of resistance, while a low level of resistance with high frequency (41%) was observed when katG codon 315 coexisted with the mutation at codon 463. Since most of the observed mutations of all three genes coexisted with the katG315 mutation, screening of katG315 mutations will be a useful marker for molecular detection of INH resistance of MTb in Sri Lanka.

  7. Arsenic-resistant and plant growth-promoting Firmicutes and γ-Proteobacteria species from industrially polluted irrigation water and corresponding cropland.

    Science.gov (United States)

    Qamar, N; Rehman, Y; Hasnain, S

    2017-09-01

    The aim of the study was to explore irrigation water polluted with industrial waste and corresponding cropland to screen bacteria for As detoxification and plant growth promotion. Plant growth-promoting (PGP) As-resistant cropland bacteria were isolated from contaminated irrigation water and corresponding agricultural soil. Phylogenetic analysis revealed that the isolates belonged to two distinct bacterial lineages; Firmicutes and γ-Proteobacteria. Maximum As(V) resistance was exhibited by Klebsiella pneumoniae T22 and Klebsiella oxytoca N53 (550 mmol l -1 ), whereas maximum resistance against As(III) was exhibited by K. oxytoca N53 (200 mmol l -1 ). Maximum As(V) reduction was shown by K. pneumoniae T22 (6·7 mmol l -1 ), whereas maximum As(III) oxidation was exhibited by Bacillus subtilis T23 (4·8 mmol l -1 ). As resistance genes arsB and ACR3 were detected in many of the isolates through polymerase chain reaction. Many of these isolates exhibited PGP traits such as hydrogen cyanide and auxin production as well as phosphate solubilization. The bacterial strains were able to enhance Triticum aestivum growth both in the absence and presence of As, and statistically significant increase in shoot and root lengths was observed especially in case of Acinetobacter lwoffii T24 and Citrobacter freundii N52-treated plants. Cropland bacteria have the ability to support plant growth. Bacteria of croplands irrigated with industrially polluted water develop resistance against toxicants. These bacteria are helpful for the plant growth in such contaminated lands. The bacteria capable of both As detoxification and plant growth promotion, such as A. lwoffii T24 and C. freundii N52, are ideal for remediation and reclamation of polluted lands for agriculture purposes. © 2017 The Society for Applied Microbiology.

  8. Micro-scale intermixing: a requisite for stable and synergistic co-establishment in a four-species biofilm.

    Science.gov (United States)

    Liu, Wenzheng; Russel, Jakob; Burmølle, Mette; Sørensen, Søren J; Madsen, Jonas S

    2018-04-18

    Microorganisms frequently coexist in complex multispecies communities, where they distribute non-randomly, reflective of the social interactions that occur. It is therefore important to understand how social interactions and local spatial organization influences multispecies biofilm succession. Here the localization of species pairs was analyzed in three dimensions in a reproducible four-species biofilm model, to study the impact of spatial positioning of individual species on the temporal development of the community. We found, that as the biofilms developed, species pairs exhibited distinct intermixing patterns unique to the four-member biofilms. Higher biomass and more intermixing were found in four-species biofilms compared to biofilms with fewer species. Intriguingly, in local regions within the four member biofilms where Microbacterium oxydans was scant, both biomass and intermixing of all species were lowered, compared to regions where M. oxydans was present at typical densities. Our data suggest that Xanthomonas retroflexus and M. oxydans, both low abundant biofilm-members, intermixed continuously during the development of the four-species biofilm, hereby facilitating their own establishment. In turn, this seems to have promoted distinct spatial organization of Stenotrophomonas rhizophila and Paenibacillus amylolyticus enabling enhanced growth of all four species. Here local intermixing of bacteria advanced the temporal development of a multi-species biofilm.

  9. Growth and (137)Cs uptake of four Brassica species influenced by inoculation with a plant growth-promoting rhizobacterium Bacillus pumilus in three contaminated farmlands in Fukushima prefecture, Japan.

    Science.gov (United States)

    Aung, Han Phyo; Djedidi, Salem; Oo, Aung Zaw; Aye, Yi Swe; Yokoyama, Tadashi; Suzuki, Sohzoh; Sekimoto, Hitoshi; Bellingrath-Kimura, Sonoko Dorothea

    2015-07-15

    The effectiveness of the plant growth-promoting rhizobacterium Bacillus pumilus regarding growth promotion and radiocesium ((137)Cs) uptake was evaluated in four Brassica species grown on different (137)Cs contaminated farmlands at Fukushima prefecture in Japan from June to August 2012. B. pumilus inoculation did not enhance growth in any of the plants, although it resulted in a significant increase of (137)Cs concentration and higher (137)Cs transfer from the soil to plants. The Brassica species exhibited different (137)Cs uptake abilities in the order Komatsuna>turnip>mustard>radish. TF values of (137)Cs ranged from 0.018 to 0.069 for all vegetables. Komatsuna possessed the largest root surface area and root volume, and showed a higher (137)Cs concentration in plant tissue and higher (137)Cs TF values (0.060) than the other vegetables. Higher (137)Cs transfer to plants was prominent in soil with a high amount of organic matter and an Al-vermiculite clay mineral type. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Growth and {sup 137}Cs uptake of four Brassica species influenced by inoculation with a plant growth-promoting rhizobacterium Bacillus pumilus in three contaminated farmlands in Fukushima prefecture, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Aung, Han Phyo [United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509 (Japan); Djedidi, Salem; Oo, Aung Zaw [Institute of Agriculture, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509 (Japan); Aye, Yi Swe [Department of International Environmental and Agricultural Science, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509 (Japan); Yokoyama, Tadashi; Suzuki, Sohzoh [Institute of Agriculture, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509 (Japan); Sekimoto, Hitoshi [Faculty of Agriculture, Utsunomiya University, 321-8505 (Japan); Bellingrath-Kimura, Sonoko Dorothea, E-mail: skimura@cc.tuat.ac.jp [Institute of Agriculture, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509 (Japan)

    2015-07-15

    The effectiveness of the plant growth-promoting rhizobacterium Bacillus pumilus regarding growth promotion and radiocesium ({sup 137}Cs) uptake was evaluated in four Brassica species grown on different {sup 137}Cs contaminated farmlands at Fukushima prefecture in Japan from June to August 2012. B. pumilus inoculation did not enhance growth in any of the plants, although it resulted in a significant increase of {sup 137}Cs concentration and higher {sup 137}Cs transfer from the soil to plants. The Brassica species exhibited different {sup 137}Cs uptake abilities in the order Komatsuna > turnip > mustard > radish. TF values of {sup 137}Cs ranged from 0.018 to 0.069 for all vegetables. Komatsuna possessed the largest root surface area and root volume, and showed a higher {sup 137}Cs concentration in plant tissue and higher {sup 137}Cs TF values (0.060) than the other vegetables. Higher {sup 137}Cs transfer to plants was prominent in soil with a high amount of organic matter and an Al-vermiculite clay mineral type. - Highlights: • PGPR inoculation did not enhance plant biomass of tested plants. • PGPR inoculation resulted in higher {sup 137}Cs concentration in plants. • Komatsuna that had larger root volume showed higher {sup 137}Cs TF from soil to plants. • Soil with high SOM and Al-vermiculite caused larger {sup 137}Cs transfer to plants.

  11. Community structure informs species geographic distributions

    KAUST Repository

    Montesinos-Navarro, Alicia

    2018-05-23

    Understanding what determines species\\' geographic distributions is crucial for assessing global change threats to biodiversity. Measuring limits on distributions is usually, and necessarily, done with data at large geographic extents and coarse spatial resolution. However, survival of individuals is determined by processes that happen at small spatial scales. The relative abundance of coexisting species (i.e. \\'community structure\\') reflects assembly processes occurring at small scales, and are often available for relatively extensive areas, so could be useful for explaining species distributions. We demonstrate that Bayesian Network Inference (BNI) can overcome several challenges to including community structure into studies of species distributions, despite having been little used to date. We hypothesized that the relative abundance of coexisting species can improve predictions of species distributions. In 1570 assemblages of 68 Mediterranean woody plant species we used BNI to incorporate community structure into Species Distribution Models (SDMs), alongside environmental information. Information on species associations improved SDM predictions of community structure and species distributions moderately, though for some habitat specialists the deviance explained increased by up to 15%. We demonstrate that most species associations (95%) were positive and occurred between species with ecologically similar traits. This suggests that SDM improvement could be because species co-occurrences are a proxy for local ecological processes. Our study shows that Bayesian Networks, when interpreted carefully, can be used to include local conditions into measurements of species\\' large-scale distributions, and this information can improve the predictions of species distributions.

  12. Stable coexistence of genetically divergent Atlantic cod ecotypes at multiple spatial scales

    DEFF Research Database (Denmark)

    Knutsen, Halvor; Jorde, Per Erik; Hutchings, Jeffrey A.

    2018-01-01

    Coexistence in the same habitat of closely related yet genetically different populations is a phenomenon that challenges our understanding of local population structure and adaptation. Identifying the underlying mechanisms for such coexistence can yield new insight into adaptive evolution...

  13. Nuclear shape coexistence and the study of nuclei far from stability

    International Nuclear Information System (INIS)

    Wood, J.L.

    1987-01-01

    The systematic features of shape coexistence are briefly outlined. The most useful spectroscopic fingerprints for identifying shape coexistence far from stability are presented. Directions for future work are discussed

  14. Community assembly and coexistence in communities of arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Vályi, Kriszta; Mardhiah, Ulfah; Rillig, Matthias C; Hempel, Stefan

    2016-10-01

    Arbuscular mycorrhizal fungi are asexual, obligately symbiotic fungi with unique morphology and genomic structure, which occupy a dual niche, that is, the soil and the host root. Consequently, the direct adoption of models for community assembly developed for other organism groups is not evident. In this paper we adapted modern coexistence and assembly theory to arbuscular mycorrhizal fungi. We review research on the elements of community assembly and coexistence of arbuscular mycorrhizal fungi, highlighting recent studies using molecular methods. By addressing several points from the individual to the community level where the application of modern community ecology terms runs into problems when arbuscular mycorrhizal fungi are concerned, we aim to account for these special circumstances from a mycocentric point of view. We suggest that hierarchical spatial structure of arbuscular mycorrhizal fungal communities should be explicitly taken into account in future studies. The conceptual framework we develop here for arbuscular mycorrhizal fungi is also adaptable for other host-associated microbial communities.

  15. On channel selection and shape co-existence

    International Nuclear Information System (INIS)

    Dracoulis, G.D.

    1993-08-01

    Ambivalence with respect to a favoured shape is emerging as a ubiquitous phenomenon in nuclei. Multiple minima in the nuclear potential well occur because of the delicate balance in nuclei between the long and short-range properties of the nuclear force and the contribution specific particle orbitals make in forcing the nucleus to a decision. Exploration of the dependence of the resulting shape co-existence on particle number and orbital is a prominent area of research. Experimental aspects of spectroscopy studies using heavy ion fusion, evaporation reactions and channel selection are discussed, with focus on shape co-existence in the light Os-Pt-Hg-Pb region. 42 refs., 8 figs

  16. Education for a Culture of Peace and Co-Existence

    Directory of Open Access Journals (Sweden)

    Silvia Guetta

    2016-07-01

    Full Text Available Education is a key and fundamental tool required to achieve social change, especially regarding social cohesion and co-existence. Education affects the most critical issues facing humanity, including the proliferation of various forms of violence, environmental degradation, and annihilation of cultures. I argue that the impact of education is equal to that of economics, politics, and technological advances. Therefore, if we wish to see change, educational reform has to be designed to operate in a global-human context, empowering and allowing people to achieve their potential. It should instil in individuals and groups respect for others with whom they interact, in a global as well as local sense. The article draws on the theories of Edgar Morin, Reuven Feuerstein, and Jerome Bruner, and their contributions to the development of educational approaches that encourage a culture of responsible, participatory, and creative coexistence. .

  17. Coexistence of pheochromocytoma/praganglioma and renal artery stenosis

    Directory of Open Access Journals (Sweden)

    Vijaya Sarathi

    2012-01-01

    Full Text Available Renal artery stenosis (RAS often coexists with pheochromocytoma (Pheo/paraganglioma (PGL and often alters the management of patients with Pheo/PGL. We have studied the prevalence of RAS in our Pheo/PGL patients. The study included 70 consecutive, histopathologically proven Pheo/PGL patients from a tertiary health care center. In 60 patients, tumors were limited to adrenal glands (54 unilateral and 6 bilateral while other 10 patients had extra-adrenal abdominal tumors. Five patients had RAS with an overall prevalence of 14%. Only two out of 60 patients with Pheo had RAS with a low prevalence of 3.3% while three out of 10 patients with extra-adrenal abdominal PGL had RAS with a prevalence of 30%. To conclude, RAS commonly coexists with Pheo/PGL, more often with extra-adrenal PGL.

  18. Hierarchical-control-based output synchronization of coexisting attractor networks

    International Nuclear Information System (INIS)

    Yun-Zhong, Song; Yi-Fa, Tang

    2010-01-01

    This paper introduces the concept of hierarchical-control-based output synchronization of coexisting attractor networks. Within the new framework, each dynamic node is made passive at first utilizing intra-control around its own arena. Then each dynamic node is viewed as one agent, and on account of that, the solution of output synchronization of coexisting attractor networks is transformed into a multi-agent consensus problem, which is made possible by virtue of local interaction between individual neighbours; this distributed working way of coordination is coined as inter-control, which is only specified by the topological structure of the network. Provided that the network is connected and balanced, the output synchronization would come true naturally via synergy between intra and inter-control actions, where the Tightness is proved theoretically via convex composite Lyapunov functions. For completeness, several illustrative examples are presented to further elucidate the novelty and efficacy of the proposed scheme. (general)

  19. 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

  20. Region effects influence local tree species diversity.

    Science.gov (United States)

    Ricklefs, Robert E; He, Fangliang

    2016-01-19

    Global patterns of biodiversity reflect both regional and local processes, but the relative importance of local ecological limits to species coexistence, as influenced by the physical environment, in contrast to regional processes including species production, dispersal, and extinction, is poorly understood. Failure to distinguish regional influences from local effects has been due, in part, to sampling limitations at small scales, environmental heterogeneity within local or regional samples, and incomplete geographic sampling of species. Here, we use a global dataset comprising 47 forest plots to demonstrate significant region effects on diversity, beyond the influence of local climate, which together explain more than 92% of the global variation in local forest tree species richness. Significant region effects imply that large-scale processes shaping the regional diversity of forest trees exert influence down to the local scale, where they interact with local processes to determine the number of coexisting species.

  1. [Central aleolar choroidal dystrophy in sibilings coexisting with alopecia].

    Science.gov (United States)

    Brydak-Godowska, Joanna; Dróbecka-Brydak, Ewa; Paćkowska, Maria; Kecik, Dariusz

    2007-01-01

    Central areolar choroidal dystrophy is localized in macular region and is characterized by atrophy of pigment epithelium, photoreceptors and choriocapillaris. This paper presents the history of two sibilings at the age of 23 and 30, with central aleolar choroidal dystrophy coexisting with alopecia. The results of erg, eog and fluorescein angiography are presented. The results of therapy for glaucoma associated with the Sturge-Weber syndrome are often disappointing.

  2. Shape coexistence in 72Kr at finite angular momentum

    International Nuclear Information System (INIS)

    Almehed, Daniel; Walet, Niels R.

    2004-01-01

    We investigate shape coexistence in a rotating nucleus. We concentrate on the case of 72 Kr which exhibits an interesting interplay between prolate and oblate shaped states as a function of angular momentum. The calculation uses the local harmonic version of the method of self-consistent adiabatic large-amplitude collective motion. We analyse how the collective behaviour of the system changes with angular momentum and we focus on the role of non-axial shapes

  3. Coexistence of pairing gaps in three-component Fermi gases

    International Nuclear Information System (INIS)

    Nummi, O H T; Kinnunen, J J; Toermae, P

    2011-01-01

    We study a three-component superfluid Fermi gas in a spherically symmetric harmonic trap using the Bogoliubov-deGennes method. We predict a coexistence phase in which two pairing field order parameters are simultaneously non-zero, in stark contrast to studies performed for trapped gases using local density approximation. We also discuss the role of atom number conservation in the context of a homogeneous system.

  4. Noncanonical quantization-on the coexistence of particles and ghosts

    International Nuclear Information System (INIS)

    Saller, H.

    1988-01-01

    Local interactions of quantized fields are sometimes parametrized with the aid of ghostlike degrees of freedom, e.g., in non-Abelian gauge theories. These ghosts do not necessarily lead to eigenstates of energy. Such a situation requires a discussion of the asymptotic boundary condition for the ghosts, leading to ghost propagation only for timelike distance. Coexisting particle and ghost degrees of freedom in one basic field operator allow the formulation of interactions for such a field without local ambiguities

  5. Shape coexistence and mixing in N ∼ 20 region

    International Nuclear Information System (INIS)

    Utsuno, Yutaka; Otsuka, Takaharu; Mizusaki, Takahiro; Honma, Michio

    2005-01-01

    Spherical-deformed shape coexistence in the N ∼ 20 region is studied with the Monte Carlo shell model calculation. We focused upon the role of the configuration mixing in its description, and found that the deformed state is not correctly positioned until the mixing is treated in a proper way. It is also mentioned that the intruder component in 33 Al is accessible through the measurement of the magnetic moment

  6. Coexistence of Schizophrenia and Frontotemporal Dementia: A Case Report

    OpenAIRE

    Zafer Subasi

    2014-01-01

    With this case, it is aimed to present a patient who was followed up with a diagnosis of schizophrenia nearly 30 years, had personality and behaviour changes added to clinical course for the last 4-5 years, had diagnostic confusion and was finally diagnosed with frontotemporal dementia superimposed on schizophrenia.Neurodegenerative diseases should be considered as either differential diagnosis or coexistence in case of symptoms such as cognitive decline or personality and behavior changes oc...

  7. An approach to unraveling the coexistence of snappers (Lutjanidae using otolith morphology

    Directory of Open Access Journals (Sweden)

    Zahra Sadighzadeh

    2014-09-01

    Full Text Available The sagittae otolith morphology of marine fishes has been used in many ecomorphological studies to explain certain ecological adaptations of species to habitat. Our study compares the sagittal otolith shapes of ten species of snappers (Family Lutjanidae inhabiting the Persian Gulf. We used a morphometric analysis of the otolith measurements (length, height, perimeter, area and weight and of the ratio between the area of the sulcus acusticus and the area of the otolith (S:O. The otolith contour was also analysed using wavelets as a mathematical descriptor. Morphological variations in the otoliths were associated with the morphology and external colouration of snappers as well as ecological traits. An analysis of the interspecific S:O ratio suggested that the highest ratios occurred in snappers inhabiting shallower waters. A categorical multivariate analysis, including morphological, ecological and otolith size factors, showed that the species adapted to dim light conditions had a greater otolith perimeter. An analysis of variance of the otolith contour revealed zones with a higher interspecific variability, although only the antero-dorsal zone showed differing patterns. Although the otolith patterns appear to have a phylogenetic component, they might also be related to diel activity rhythms or to the light conditions in the habitat. The results of the study showed that variation in otolith morphology can be used to explain the coexistence of sympatric species.

  8. Digital Ecology: Coexistence and Domination among Interacting Networks

    Science.gov (United States)

    Kleineberg, Kaj-Kolja; Boguñá, Marián

    2015-05-01

    The overwhelming success of Web 2.0, within which online social networks are key actors, has induced a paradigm shift in the nature of human interactions. The user-driven character of Web 2.0 services has allowed researchers to quantify large-scale social patterns for the first time. However, the mechanisms that determine the fate of networks at the system level are still poorly understood. For instance, the simultaneous existence of multiple digital services naturally raises questions concerning which conditions these services can coexist under. Analogously to the case of population dynamics, the digital world forms a complex ecosystem of interacting networks. The fitness of each network depends on its capacity to attract and maintain users’ attention, which constitutes a limited resource. In this paper, we introduce an ecological theory of the digital world which exhibits stable coexistence of several networks as well as the dominance of an individual one, in contrast to the competitive exclusion principle. Interestingly, our theory also predicts that the most probable outcome is the coexistence of a moderate number of services, in agreement with empirical observations.

  9. Coexistence of cluster structure and superdeformation in 44Ti

    International Nuclear Information System (INIS)

    Kimura, Masaaki; Horiuchi, Hisashi

    2006-01-01

    The nucleus 44 Ti has low-lying levels of various kinds of mutually very different nuclear structure displaying the richness of the nuclear many-body dynamics. It is shown that the deformed-basis antisymmetrized molecular dynamics by the use of the Gogny D1S force reproduces successfully and unifiedly two types of coexistence phenomena in 44 Ti. Namely, on one hand, the coexistence of the mean-field structure and the cluster structure is confirmed by verifying the normally deformed structure of the K π =3 1 - band with a 1-particle-1-hole intrinsic configuration and the α+Ca40 cluster structure of the K π =0 2 - band. The mixed character of the mean-field-like structure and the α+Ca40 cluster structure of the ground band is also shown. On the other hand, the coexistence of the normal deformed mean-field and the superdeformed mean-field is confirmed by verifying the triaxial superdeformation of the K π =0 2 + band and the K π =2 1 + band which has a 4-particle-4-hole intrinsic configuration. Good reproduction of the experimental data is shown for many kinds of quantities including the energy spectra, electric transition rates, alpha spectroscopic factors. Preliminary discussions are given on the existence of hyperdeformed excited states, the relation between superdeformation and clustering and so on

  10. Coexistence of cluster structure and superdeformation in {sup 44}Ti

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Masaaki [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)]. E-mail: masaaki@yukawa.kyoto-u.ac.jp; Horiuchi, Hisashi [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan)

    2006-03-06

    The nucleus {sup 44}Ti has low-lying levels of various kinds of mutually very different nuclear structure displaying the richness of the nuclear many-body dynamics. It is shown that the deformed-basis antisymmetrized molecular dynamics by the use of the Gogny D1S force reproduces successfully and unifiedly two types of coexistence phenomena in {sup 44}Ti. Namely, on one hand, the coexistence of the mean-field structure and the cluster structure is confirmed by verifying the normally deformed structure of the K{sup {pi}}=3{sub 1}{sup -} band with a 1-particle-1-hole intrinsic configuration and the {alpha}+Ca40 cluster structure of the K{sup {pi}}=0{sub 2}{sup -} band. The mixed character of the mean-field-like structure and the {alpha}+Ca40 cluster structure of the ground band is also shown. On the other hand, the coexistence of the normal deformed mean-field and the superdeformed mean-field is confirmed by verifying the triaxial superdeformation of the K{sup {pi}}=0{sub 2}{sup +} band and the K{sup {pi}}=2{sub 1}{sup +} band which has a 4-particle-4-hole intrinsic configuration. Good reproduction of the experimental data is shown for many kinds of quantities including the energy spectra, electric transition rates, alpha spectroscopic factors. Preliminary discussions are given on the existence of hyperdeformed excited states, the relation between superdeformation and clustering and so on.

  11. Education of Coexistence as Technē Tou Biou

    Directory of Open Access Journals (Sweden)

    Tomas Kačerauskas

    2011-02-01

    Full Text Available The article deals with education of coexistence as training of life art (technē tou biou. The major thesis is the following: our existence has been educated in the life environment together with other agents of life world (Lebenswelt, while the latter are educated in the background of our existential project to be realized during our life. This major thesis presupposes the minor ones developed in the article: existential education means the change of the roles between the agents of life enwironment; existential education covers an ironic relationship between the teacher and a disciple; the teacher educates an unique combination of the disciple’s charachteristics to be nourished in his (her existential perspective instead of forcing the equal way for everybody; every community has been educated while an individual changes life environment by realization of his (her existential utopia; education is a kind of existential tradition’s transfer through the new communicative channels; philosophy of education based on existential phenomenology stresses the aspects of responsible coexistence in the life-world to be created; education is the training of our life’s art as responsible creation inseparable from becoming of life-world as the environment of our coexistence; education deals with a miracle of breaking educational circle while a disciple excels the teacher and changes the educational environment. By analysing the problems of existential education the author uses the approaches of both existential phenomenology and cultural regionalistics. 

  12. EGFR and KRAS mutation coexistence in lung adenocarcinomas

    Directory of Open Access Journals (Sweden)

    Vitor Manuel Leitão de Sousa

    2015-04-01

    Full Text Available Lung cancer is one of the most common causes of cancer deaths. The development of EGFR targeted therapies, including monoclonal antibodies and tyrosine kinase inhibitors have generated an interest in the molecular characterization of these tumours. KRAS mutations are associated with resistance to EGFR TKIs. EGFR and KRAS mutations have been considered as mutually exclusive. This paper presents three bronchial-pulmonary carcinomas, two adenocarcinomas and one pleomorphic sarcomatoid carcinoma, harboring EGFR and KRAS mutations. Case 1 corresponded to an adenocarcinoma with EGFR exon 21 mutation (L858R and KRAS codon 12 point mutation (G12V; case 2, a  mucinous adenocarcinoma expressed coexistence of EGFR exon 21 mutation (L858R and KRAS codon 12 point mutation (G12V; and case 3 a sarcomatoid carcinoma with EGFR exon 19 deletion – del 9bp and KRAS codon 12 point mutation (G12C - cysteine. Based on our experience and on the literature, we conclude that EGFR and KRAS mutations can indeed coexist in the same bronchial-pulmonary carcinoma, either in the same histological type or in different patterns. The biological implications of this coexistence are still poorly understood mainly because these cases are not frequent or currently searched. It is therefore necessary to study larger series of cases with the two mutations to better understand the biological, clinical and therapeutic implications.

  13. Nuclear Coexistence: Rethinking U.S. Policy to Promote Stability in an Era of Proliferation

    Science.gov (United States)

    1994-04-01

    into the effects of Israel’s nuclear weapons on regional stability. 25. See David Albright and Mark Hibbs, "Iraq’s Bomb: Blueprints and Artifacts...Foreign Minister Andrei V. Kozyrev warned Ukraine that the possession of deteriorating nuclear warheads could lead to an accident.32 Sovereign Control and...longstanding political disputes. By the standard of nuclear bipolarity, the nuclear politics on the subcontinent are largely a mirror of the U.S.-Soviet nuclear

  14. How successful is the BRICS in promoting coexistence as an alternative framework for global governance?

    DEFF Research Database (Denmark)

    Mandrup, Thomas; Odgaard, Liselotte; de Coning, Cedric

    2016-01-01

    -interference in the internal affairs of other states and respects the independence, sovereignty and territorial integrity of Ukraine. However, it recognizes that Western support for revolutions in former Soviet Republics initiated the breach of the principle of non-interference, and contributed to an environment of high......, and not to violate the sovereignty and territorial integrity of other states. Russia’s partners in the BRICS have signalled that whilst they understand Russia’s motives they are uncomfortable with its actions. China, for instance, clarified that it remains committed to the principle of non...... strategy pursued by the BRICS consists of four basic principles: mutual respect for sovereignty and territorial integrity; interference in the internal affairs of other states only within the framework of multilaterally agreed upon norms and rules; mutual non-aggression and the legal equality of states...

  15. Wear Particles Promote Reactive Oxygen Species-Mediated Inflammation via the Nicotinamide Adenine Dinucleotide Phosphate Oxidase Pathway in Macrophages Surrounding Loosened Implants

    Directory of Open Access Journals (Sweden)

    Weishen Chen

    2015-03-01

    Full Text Available Background/Aims: Prosthesis loosening is closely associated with chronic inflammatory cytokine secretion by macrophages, which are activated by wear particles or inflammatory stimulants such as lipopolysaccharide (LPS. Reactive oxygen species (ROS are critical regulators of inflammation, but their enzymatic sources in response to wear particles and their effects on peri-implant LPS-tolerance remain unclear. Methods: Three ROS-related enzymes—nicotinamide adenine dinucleotide phosphate oxidase (NOX-1 and -2 and catalase—were investigated in interface membrane tissues and in titanium (Ti particle-stimulated macrophages in vitro. The generation of ROS and downstream inflammatory effects were measured with or without pre-incubation with apocynin, an NOX inhibitor. Results: Pre-exposure to Ti particles attenuated NF-κB activation in LPS-stimulated macrophages, indicating that wear particles suppress immune response, which may lead to chronic inflammation. NOX-1 and -2 were highly expressed in aseptically loosened interface membranes and in macrophages stimulated with Ti particles; the particles induced a moderate amount of ROS generation, NF-κB activation, and TNF-a secretion in macrophages, and these effects were suppressed by apocynin. Conclusion: Wear particles induce ROS generation through the NOX signaling pathway, resulting in persistent inflammation and delayed loosening. Thus, the suppression of NOX activity may be a useful strategy for preventing prosthesis loosening.

  16. Phytoplankton abundance, dominance and coexistence in an eutrophic reservoir in the state of Pernambuco, Northeast Brazil

    Directory of Open Access Journals (Sweden)

    Giulliari A. S. T. Lira

    2011-12-01

    Full Text Available The present study reports the phytoplankton abundance, dominance and co-existence relationships in the eutrophic Carpina reservoir, Pernambuco, Brazil. Sampling was carried out at six different depths bimonthly at a single reservoir spanning two climatic periods: dry season (January, September, and November 2006 and rainy season (March, May, and July 2006. Density, abundance, dominance, specific diversity and equitability of the community were determined, along with chlorophyll a, and physical and chemical variables of the environment. Eight species were considered abundant, and their densities corresponded to more than 90% of the total phytoplankton community quantified. Cyanobacteria represented more than 80% of this density. Cylindrospermopsis raciborskii was the only dominant taxon in the dry season, and was co-dominant in the rainy season. C. raciborskii, Planktothrix agardhii and Geitlerinema amphibium had the greatest densities and lowest vertical variation coefficients. The statistical analysis indicated relationships with vertical and seasonal variations in the phytoplankton community and the following variables: total dissolved solids, water temperature, electrical conductivity and pH. The changes in the environmental variables were discrete and regulated by the establishment of precipitation however, they were able to promote vertical and seasonal instability in the structure of the phytoplankton community.O presente estudo remete às relações de abundância, dominância e co-existência fitoplanctônica no reservatório eutrófico de Carpina, Pernambuco, Brasil. Foram realizadas amostragens bimensalmente, em seis profundidades, em um único ponto do reservatório, contemplando dois períodos sazonais: seco (janeiro, setembro e novembro/2006 e chuvoso (março, maio e julho/2006. A densidade, abundância, dominância, diversidade específica e equitabilidade foram determinadas, além da clorofila a e algumas variáveis físicas e qu

  17. The influence of deterministic and stochastic waiting time for triggering mortality and colonization events on the coexistence of cooperators and defectors in an evolutionary game model

    Directory of Open Access Journals (Sweden)

    YouHua Chen

    2014-06-01

    waiting time, both defectors and cooperators could coexist, regardless of the types of waiting time for colonization events. Defense (or cooperation rewards could determine the persistence time of both game players. When the defense reward is low, cooperators could persist better in the simulation. But when the defense reward becomes sufficiently higher, defectors would persist better. Overall, non-coexistence of cooperators and defectors in the present evolutionary game model is dependent on the stochastic mortality events, but not colonization events. In conclusion, my present study quantifies the influence of the temporally fluctuating motility-colonization dynamic on modeling the coexistence of species in the spatial evolutionary game.

  18. The role of gaping behaviour in habitat partitioning between coexisting intertidal mussels

    Directory of Open Access Journals (Sweden)

    Stephens Linda

    2010-07-01

    Full Text Available Abstract Background Environmental heterogeneity plays a major role in invasion and coexistence dynamics. Habitat segregation between introduced species and their native competitors is usually described in terms of different physiological and behavioural abilities. However little attention has been paid to the effects of behaviour in habitat partitioning among invertebrates, partially because their behavioural repertoires, especially marine benthic taxa, are extremely limited. This study investigates the effect of gaping behaviour on habitat segregation of the two dominant mussel species living in South Africa, the invasive Mytilus galloprovincialis and the indigenous Perna perna. These two species show partial habitat segregation on the south coast of South Africa, the lower and upper areas of the mussel zone are dominated by P. perna and M. galloprovincialis respectively, with overlap in the middle zone. During emergence, intertidal mussels will either keep the valves closed, minimizing water loss and undergoing anaerobic metabolism, or will periodically open the valves maintaining a more efficient aerobic metabolism but increasing the risk of desiccation. Results Our results show that, when air exposed, the two species adopt clearly different behaviours. M. galloprovincialis keeps the shell valves closed, while P. perna periodically gapes. Gaping behaviour increased water loss in the indigenous species, and consequently the risk of desiccation. The indigenous species expressed significantly higher levels of stress protein (Hsp70 than M. galloprovincialis under field conditions and suffered significantly higher mortality rates when exposed to air in the laboratory. In general, no intra-specific differences were observed in relation to intertidal height. The absence of gaping minimises water loss but exposes the invasive species to other stresses, probably related to anoxic respiration. Conclusions Gaping affects tolerance to desiccation, thus

  19. Mitochondrial Reactive Oxygen Species in Lipotoxic Hearts Induce Post-Translational Modifications of AKAP121, DRP1, and OPA1 That Promote Mitochondrial Fission.

    Science.gov (United States)

    Tsushima, Kensuke; Bugger, Heiko; Wende, Adam R; Soto, Jamie; Jenson, Gregory A; Tor, Austin R; McGlauflin, Rose; Kenny, Helena C; Zhang, Yuan; Souvenir, Rhonda; Hu, Xiao X; Sloan, Crystal L; Pereira, Renata O; Lira, Vitor A; Spitzer, Kenneth W; Sharp, Terry L; Shoghi, Kooresh I; Sparagna, Genevieve C; Rog-Zielinska, Eva A; Kohl, Peter; Khalimonchuk, Oleh; Schaffer, Jean E; Abel, E Dale

    2018-01-05

    Cardiac lipotoxicity, characterized by increased uptake, oxidation, and accumulation of lipid intermediates, contributes to cardiac dysfunction in obesity and diabetes mellitus. However, mechanisms linking lipid overload and mitochondrial dysfunction are incompletely understood. To elucidate the mechanisms for mitochondrial adaptations to lipid overload in postnatal hearts in vivo. Using a transgenic mouse model of cardiac lipotoxicity overexpressing ACSL1 (long-chain acyl-CoA synthetase 1) in cardiomyocytes, we show that modestly increased myocardial fatty acid uptake leads to mitochondrial structural remodeling with significant reduction in minimum diameter. This is associated with increased palmitoyl-carnitine oxidation and increased reactive oxygen species (ROS) generation in isolated mitochondria. Mitochondrial morphological changes and elevated ROS generation are also observed in palmitate-treated neonatal rat ventricular cardiomyocytes. Palmitate exposure to neonatal rat ventricular cardiomyocytes initially activates mitochondrial respiration, coupled with increased mitochondrial polarization and ATP synthesis. However, long-term exposure to palmitate (>8 hours) enhances ROS generation, which is accompanied by loss of the mitochondrial reticulum and a pattern suggesting increased mitochondrial fission. Mechanistically, lipid-induced changes in mitochondrial redox status increased mitochondrial fission by increased ubiquitination of AKAP121 (A-kinase anchor protein 121) leading to reduced phosphorylation of DRP1 (dynamin-related protein 1) at Ser637 and altered proteolytic processing of OPA1 (optic atrophy 1). Scavenging mitochondrial ROS restored mitochondrial morphology in vivo and in vitro. Our results reveal a molecular mechanism by which lipid overload-induced mitochondrial ROS generation causes mitochondrial dysfunction by inducing post-translational modifications of mitochondrial proteins that regulate mitochondrial dynamics. These findings provide a

  20. Reactive oxygen species promote tubular injury in diabetic nephropathy: The role of the mitochondrial ros-txnip-nlrp3 biological axis

    Directory of Open Access Journals (Sweden)

    Yachun Han

    2018-06-01

    Full Text Available NLRP3/IL-1β activation via thioredoxin (TRX/thioredoxin-interacting protein (TXNIP following mitochondria ROS (mtROS overproduction plays a key role in inflammation. However, the involvement of this process in tubular damage in the kidneys of patients with diabetic nephropathy (DN is unclear. Here, we demonstrated that mtROS overproduction is accompanied by decreases in TRX expression and TXNIP up-regulation. In addition, we discovered that mtROS overproduction is also associated with increases in NLRP3/IL-1β and TGF-β expression in the kidneys of patients with DN and db/db mice. We reversed these changes in db/db mice by administering a peritoneal injection of MitoQ, an antioxidant targeting mtROS. Similar results were observed in human tubular HK-2 cells subjected to high-glucose (HG conditions and treated with MitoQ. Treating HK-2 cells with MitoQ suppressed the dissociation of TRX from TXNIP and subsequently blocked the interaction between TXNIP and NLRP3, leading to the inhibition of NLRP3 inflammasome activation and IL-1β maturation. The effects of MitoQ were enhanced by pretreatment with TXNIP siRNA and abolished by pretreatment with monosodium urate (MSU and TRX siRNA in vitro. These results suggest that mitochondrial ROS-TXNIP/NLRP3/IL-1β axis activation is responsible for tubular oxidative injury, which can be ameliorated by MitoQ via the inhibition of mtROS overproduction. Keywords: Diabetic nephropathy, Mitochondria, Reactive oxygen species (ROS, TRX/TXNIP, NLRP3 inflammasome, MitoQ

  1. High Glucose Promotes Tumor Invasion and Increases Metastasis-Associated Protein Expression in Human Lung Epithelial Cells by Upregulating Heme Oxygenase-1 via Reactive Oxygen Species or the TGF-β1/PI3K/Akt Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Xiaowen Kang

    2015-02-01

    Full Text Available Background: Growing evidence indicates that heme oxygenase-1 (HO-1 is up-regulated in malignancies and subsequently alters tumor aggressiveness and various cancer-related factors, such as high glucose (HG levels. HO-1 expression can be induced when glucose concentrations are above 25 mM; however, the role of HO-1 in lung cancer patients with diabetes remains unknown. Therefore, in this study we investigated the promotion of tumor cell invasion and the expression of metastasis-associated proteins by inducing the up-regulation of HO-1 expression by HG treatment in A549 human lung epithelial cells. Methods: The expression of HO-1and metastasis-associated protein expression was explored by western blot analysis. HO-1 enzymatic activity, reactive oxygen species (ROS production and TGF-β1 production were examined by ELISA. Invasiveness was analyzed using a Transwell chamber. Results: HG treatment of A549 cells induced an increase in HO-1 expression, which was mediated by the HG-induced generation of reactive oxygen species (ROS and transforming growth factor-β1 (TGF-β1 in a concentration- and time-dependent manner. Following the increase in HO-1 expression, the enzymatic activity of HO-1 also increased in HG-treated cells. Pretreatment with N-acetyl-L-cysteine (NAC or with phosphatidylinositol 3-kinase (PI3K/Akt inhibitors attenuated the HG-induced increase in HO-1 expression. HG treatment of A549 cells enhanced the invasion potential of these cells, as shown with a Transwell assay, and increased metastasis-associated protein expression. However, HO-1 siRNA transfection significantly decreased these capabilities. Conclusion: this study is the first to demonstrate that HG treatment of A549 human lung epithelial cells promotes tumor cell invasion and increases metastasis-associated protein expression by up-regulating HO-1 expression via ROS or the TGF-β1/PI3K/Akt signaling pathway.

  2. Deformation and shape coexistence in medium mass nuclei

    International Nuclear Information System (INIS)

    Meyer, R.A.

    1985-01-01

    Emerging evidence for deformed structures in medium mass nuclei is reviewed. Included in this review are both nuclei that are ground state symmetric rotors and vibrational nuclei where there are deformed structures at excited energies (shape coexistence). For the first time, Nilsson configurations in odd-odd nuclei within the region of deformation are identified. Shape coexistence in nuclei that abut the medium mass region of deformation is also examined. Recent establishment of a four-particle, four-hole intruder band in the double subshell closure nucleus 96 Zr 56 is presented and its relation to the nuclear vibron model is discussed. Special attention is given to the N=59 nuclei where new data have led to the reanalysis of 97 Sr and 99 Zr and the presence of the [404 9/2] hole intruder state as isomers in these nuclei. The low energy levels of the N=59 nuclei from Z=38 to 50 are compared with recent quadrupole-phonon model calculations that can describe their transition from near-rotational to single closed shell nuclei. The odd-odd N=59 nuclei are discussed in the context of coexisting shape isomers based on the (p[303 5/2]n[404 9/2])2 - configuration. Ongoing in-beam (t,p conversion-electron) multiparameter measurements that have led to the determination of monopole matrix elements for even-even 42 Mo nuclei are presented, and these are compared with initial estimates using IBA-2 calculations that allow mixing of normal and cross subshell excitations. Lastly, evidence for the neutron-proton 3 S 1 force's influence on the level structure of these nuclei is discussed within the context of recent quadrupole-phonon model calculations. (Auth.)

  3. Unexpected Coexisting Myocardial Infarction Detected by Delayed Enhancement MRI

    Directory of Open Access Journals (Sweden)

    Edouard Gerbaud

    2009-01-01

    Full Text Available We report a case of an unexpected coexisting anterior myocardial infarction detected by delayed enhancement MRI in a 41-year-old man following a presentation with a first episode of chest pain during inferior acute myocardial infarction. This second necrotic area was not initially suspected because there were no ECG changes in the anterior leads and the left descending coronary artery did not present any significant stenoses on emergency coronary angiography. Unrecognised myocardial infarction may carry important prognostic implications. CMR is currently the best imaging technique to detect unexpected infarcts.

  4. An IBM description of coexistence in the platinum isotopes

    International Nuclear Information System (INIS)

    Harder, M.; Tang, K.T.; Van Isacker, P.

    1996-06-01

    The low-energy spectra of the platinum isotopes show evidence for the presence of two types of configurations: one which involves only excitations of the valence nucleons and another which includes proton excitations across the Z = 82 shell gap. A schematic description is presented of the coexistence and mixing of both configurations in the context of the interacting boson model and energies, electromagnetic transition rates and moments, and radii are studied. The analysis shows that a simultaneous description of both configurations puts constraints on the possible range of model parameters. Isotope and isomer shifts are shown to be sensitive to the mixing of both configurations. (author)

  5. Thermophysical properties of hydrogen along the liquid-vapor coexistence

    Science.gov (United States)

    Osman, S. M.; Sulaiman, N.; Bahaa Khedr, M.

    2016-05-01

    We present Theoretical Calculations for the Liquid-Vapor Coexistence (LVC) curve of fluid Hydrogen within the first order perturbation theory with a suitable first order quantum correction to the free energy. In the present equation of state, we incorporate the dimerization of H2 molecule by treating the fluid as a hard convex body fluid. The thermophysical properties of fluid H2 along the LVC curve, including the pressure-temperature dependence, density-temperature asymmetry, volume expansivity, entropy and enthalpy, are calculated and compared with computer simulation and empirical results.

  6. New interpretation of shape coexistence in 99Zr

    International Nuclear Information System (INIS)

    Lhersonneau, G.; Dendooven, P.; Honkanen, A.; Huhta, M.; Jones, P.M.; Julin, R.; Juutinen, S.; Oinonen, M.; Penttilae, H.; Persson, J.R.; Peraejaervi, K.; Savelius, A.; Wang, J.C.; Aeystoe, J.

    1997-01-01

    Levels in 99 Zr populated by β decay of on-line mass separated 99 Y have been studied by γ-ray spectroscopic methods, including γ-γ coincidences recorded with an array of ten Ge detectors and level-lifetime measurements. The formerly reported strongly collective character of the 53-keV transition turns out to be questionable. This implies a revision of the experimental evidence for shape coexistence in 99 Zr. Transition rates and γ-ray branching ratios make a new level at 679 keV with t 1/2 =9 ns another candidate for a deformed state. copyright 1997 The American Physical Society

  7. Coexistence of collapse and stable spatiotemporal solitons in multimode fibers

    Science.gov (United States)

    Shtyrina, Olga V.; Fedoruk, Mikhail P.; Kivshar, Yuri S.; Turitsyn, Sergei K.

    2018-01-01

    We analyze spatiotemporal solitons in multimode optical fibers and demonstrate the existence of stable solitons, in a sharp contrast to earlier predictions of collapse of multidimensional solitons in three-dimensional media. We discuss the coexistence of blow-up solutions and collapse stabilization by a low-dimensional external potential in graded-index media, and also predict the existence of stable higher-order nonlinear waves such as dipole-mode spatiotemporal solitons. To support the main conclusions of our numerical studies we employ a variational approach and derive analytically the stability criterion for input powers for the collapse stabilization.

  8. Microscopic theory of coexistence of superconductivity and antiferromagnetism

    International Nuclear Information System (INIS)

    Ashkenazi, J.; Kuper, C.G.; Ron, A.

    1983-01-01

    A theory of the coexistence of superconductivity and antiferromagnetism is presented. We study the role of the ''diagonal'' exchange coupling between magnetic ions and conduction electrons, using Eliashberg's formalism. This coupling generates a spatial displacement of the Cooper-paired states, and thus reduces the pairing strength. The reduction is linear in the exchange integral and the staggered magnetization. The theory agrees well with experiment for Dy/sub 1.2/Mo 6 S 8 and Tb/sub 1.2/Mo 6 S 8

  9. New challenge: the development of social competition for peaceful coexistence

    Directory of Open Access Journals (Sweden)

    Rocío Ramírez Ibagon

    2005-02-01

    Full Text Available The present document describes the experiences obtained from the initiation of the Basic Development for Reconstruction of Social Abilities with Emphasis on Peaceful Co-Existence Programme. The programme includes young people who have enrolled in the National Reinsertion Programme to obtain their Secundary school Degree. It offers a profile of the population, a recount of the reasons why children and young people participate in armed conflict and also describes the reasons that influence their return. Finally, the paper makes mention of the alms and achievements of said experiences. 

  10. Discovery of the shape coexisting 0{sup +} state in {sup 32}Mg

    Energy Technology Data Exchange (ETDEWEB)

    Wimmer, Kathrin

    2010-08-16

    The evolution of shell structure in exotic nuclei as a function of proton (Z) and neutron (N) number is currently at the center of many theoretical and experimental investigations. It has been realized that the interaction of the last valence protons and neutrons, in particular the monopole component of the residual interaction between those nucleons, can lead to significant shifts in the single-particle energies, leading to the collapse of classic shell closures and the appearance of new shell gaps. The ''Island of Inversion'' around {sup 32}Mg, which is one of the most studied phenomena in the nuclear chart, is a well known example for such changes in nuclear structure. In this region of neutron-rich nuclei around the magic number N=20 strongly deformed ground states in Ne, Na, and Mg isotopes have been observed. Due to the reduction of the N=20 shell gap quadrupole correlations can enable low-lying deformed 2p-2h intruder states from the fp-shell to compete with spherical normal neutron 0p-0h states of the sd-shell. In this situation the promotion of a neutron pair across the N=20 gap can result in deformed intruder ground states. Consequentially the two competing configurations can lead to the coexistence of spherical and deformed 0{sup +} states in the neutron rich nuclei {sup 30,32}Mg. In this work the shape coexistence in {sup 32}Mg was studied by a two neutron transfer reaction at the REX-ISOLDE facility (CERN). The two neutron transfer reaction with a {sup 30}Mg beam involved for the first time the use of a radioactive tritium target in combination with a radioactive heavy ion beam. Light charged particles emitted from the target were detected and identified by the T-REX particle detector while {gamma}-rays were detected by the MINIBALL Germanium detector array. The shape of the angular distribution of the protons allows to unambiguously determine the angular momentum transfer {delta}L of the reaction and thus to identify the 0{sup

  11. Individuals and the variation needed for high species diversity in forest trees

    Science.gov (United States)

    James S. Clark

    2010-01-01

    In the past, explanations for high species diversity have been sought at the species level. Theory shows that coexistence requires substantial differences between species, but species-level data rarely provide evidence for such differences. Using data from forests in the southeastern United States, I show here that variation evident at the individual level provides for...

  12. Phenology of three coexisting annual fish species: seasonal patterns in hatching dates

    Czech Academy of Sciences Publication Activity Database

    García, D.; Loureiro, M.; Machín, E.; Reichard, Martin

    2018-01-01

    Roč. 809, č. 1 (2018), s. 323-337 ISSN 0018-8158 R&D Projects: GA ČR(CZ) GBP505/12/G112 Institutional support: RVO:68081766 Keywords : Birth date * Climate change * Hatching synchrony * Intraguild predation * Killifish * Otoliths Subject RIV: EG - Zoology Impact factor: 2.056, year: 2016

  13. Co-existence and niche segregation of three small bovid species in southern Mozambique

    NARCIS (Netherlands)

    Prins, HHT; de Boer, WF; van Oeveren, H; Correia, A; Mafuca, J; Olff, H; Boer, Willem F. de

    Niche segregation among three small antelopes - red duiker, common duiker and suni - was investigated in a coastal savanna woodland/forest mosaic. It was expected that these similar-sized concentrate selectors would show differentiation in diet choice to decrease competition. Diet composition did

  14. Co-existence and niche segregation of three small bovid species in southern Mozambique

    NARCIS (Netherlands)

    Prins, H.H.T.; Boer, de W.F.; Oeveren, van H.; Correia, A.; Mafuca, J.; Olff, H.

    2006-01-01

    Niche segregation among three small antelopes ¿ red duiker, common duiker and suni ¿ was investigated in a coastal savanna woodland/forest mosaic. It was expected that these similar-sized concentrate selectors would show differentiation in diet choice to decrease competition. Diet composition did

  15. Hatching date variability in wild populations of four coexisting species of African annual fishes

    Czech Academy of Sciences Publication Activity Database

    Reichard, Martin; Blažek, Radim; Polačik, Matej; Vrtílek, Milan

    2017-01-01

    Roč. 246, č. 11 (2017), s. 827-837 ISSN 1058-8388 R&D Projects: GA ČR(CZ) GA16-00291S Institutional support: RVO:68081766 Keywords : developmental synchrony * diapause * Nothobranchius Subject RIV: EG - Zoology OBOR OECD: Developmental biology Impact factor: 2.004, year: 2016

  16. Effect of co-existing plant specie on soil microbial activity under heavy metal stress

    International Nuclear Information System (INIS)

    Nwuche, C. O.; Ugoji, E. O.

    2010-01-01

    The influence of plant primary compounds on the activity of soil microbial communities under heavy metal stress was studied in a pot-culture field experiment conducted in a green house. Amaranthus spinosus was cultivated in an agricultural soil previously amended in the laboratory with solutions of different trace elements in two separate treatment modes: singly and in combination. Culture-independent metabolism based indices such as the rate of carbon and nitrogen mineralization, microbial biomass carbon and soil basal respiration were monitored fortnightly over a period of six weeks. Result shows that plant detritus have significant modifying effect on soil microbe-metal interactions. Data on microbial and biochemical processes in the respective mesocosms did not vary from control; not even in mesocosms containing very high concentrations of copper, zinc and nickel. The soil microbial biomass carbon and the rate of carbon and nitrogen cycling were not impeded by the respective metal treatment while the respiration responses increased as a result of increase in metabolic activity of the soil microbes. The plant based substrates enabled the soil microflora to resist high metal contamination because of its tendency to absorb large amounts of inorganic cations.

  17. Adaptive omnivory and species coexistence in tri-trophic food webs

    Czech Academy of Sciences Publication Activity Database

    Křivan, Vlastimil; Diehl, S.

    2005-01-01

    Roč. 67, č. 2 (2005), s. 85-99 ISSN 0040-5809 R&D Projects: GA ČR(CZ) GA201/03/0091 Institutional research plan: CEZ:AV0Z50070508 Keywords : omnivory * intraguild predation * diet rule Subject RIV: EH - Ecology, Behaviour Impact factor: 2.007, year: 2005

  18. Are trade-offs among species' ecological interactions scale dependent? A test using pitcher-plant inquiline species.

    Science.gov (United States)

    Kneitel, Jamie M

    2012-01-01

    Trade-offs among species' ecological interactions is a pervasive explanation for species coexistence. The traits associated with trade-offs are typically measured to mechanistically explain species coexistence at a single spatial scale. However, species potentially interact at multiple scales and this may be reflected in the traits among coexisting species. I quantified species' ecological traits associated with the trade-offs expected at both local (competitive ability and predator tolerance) and regional (competitive ability and colonization rate) community scales. The most common species (four protozoa and a rotifer) from the middle trophic level of a pitcher plant (Sarracenia purpurea) inquiline community were used to link species traits to previously observed patterns of species diversity and abundance. Traits associated with trade-offs (competitive ability, predator tolerance, and colonization rate) and other ecological traits (size, growth rate, and carrying capacity) were measured for each of the focal species. Traits were correlated with one another with a negative relationship indicative of a trade-off. Protozoan and rotifer species exhibited a negative relationship between competitive ability and predator tolerance, indicative of coexistence at the local community scale. There was no relationship between competitive ability and colonization rate. Size, growth rate, and carrying capacity were correlated with each other and the trade-off traits: Size was related to both competitive ability and predator tolerance, but growth rate and carrying capacity were correlated with predator tolerance. When partial correlations were conducted controlling for size, growth rate and carrying capacity, the trade-offs largely disappeared. These results imply that body size is the trait that provides the basis for ecological interactions and trade-offs. Altogether, this study showed that the examination of species' traits in the context of coexistence at different scales

  19. Sexual dimorphism in striatal dopaminergic responses promotes monogamy in social songbirds.

    Science.gov (United States)

    Tokarev, Kirill; Hyland Bruno, Julia; Ljubičić, Iva; Kothari, Paresh J; Helekar, Santosh A; Tchernichovski, Ofer; Voss, Henning U

    2017-08-11

    In many songbird species, males sing to attract females and repel rivals. How can gregarious, non-territorial songbirds such as zebra finches, where females have access to numerous males, sustain monogamy? We found that the dopaminergic reward circuitry of zebra finches can simultaneously promote social cohesion and breeding boundaries. Surprisingly, in unmated males but not in females, striatal dopamine neurotransmission was elevated after hearing songs. Behaviorally too, unmated males but not females persistently exchanged mild punishments in return for songs. Song reinforcement diminished when dopamine receptors were blocked. In females, we observed song reinforcement exclusively to the mate's song, although their striatal dopamine neurotransmission was only slightly elevated. These findings suggest that song-triggered dopaminergic activation serves a dual function in social songbirds: as low-threshold social reinforcement in males and as ultra-selective sexual reinforcement in females. Co-evolution of sexually dimorphic reinforcement systems can explain the coexistence of gregariousness and monogamy.

  20. From coexistence to competitive exclusion: can overfishing change the outcome of competition in skates (Chondrichthyes, Rajidae?

    Directory of Open Access Journals (Sweden)

    Natalia L Ruocco

    2012-03-01

    Full Text Available Competition for food could be a major force driving changes in the community structure of skates (Rajidae subjected to fishing exploitation. Under this hypothesis, small skates are released from competition with larger skates after fishing has depleted the larger species. Here, we compare the abundance patterns of two sympatric skates with similar niches but different life histories, Bathyraja albomaculata (larger and slow-reproducing and Bathyraja macloviana (smaller and faster-reproducing, before (1971, 1978 and after (1998-2004 a 108% increase in industrial bottom trawling on the southeastern South American shelf in order to test the prediction that B. macloviana should competitively exclude B. albomaculata after the increase in fishing mortality. In 1971 and 1978, there was no relationship between the abundance of both species, indicating that they coexisted over large scales. In 1998-2004, the relationship between the abundances of these skates was bell-shaped, indicating that both species increased in abundance at low densities until peaking, after which B. albomaculata decreased when B. macloviana became more abundant, consistent with resource competition. We tested whether food may be a potential limiting resource by comparing the diet of both species. The two species consumed mostly polychaetes, differing only in the consumption of polychaetes from the family Nephthyidae, which was much higher for B. macloviana. Bathyraja macloviana could replace B. albomaculata at high densities when food resources may become scarce. These results support the hypothesis that competition release is an important factor explaining the changes in skate communities in overexploited areas.

  1. Interspecific differentiation and hybridization in vanilla species (Orchidaceae)

    DEFF Research Database (Denmark)

    Nielsen, Lene Rostgaard; Siegismund

    1999-01-01

    Vanilla claviculata, V. barbellata and V. dilloniana are distributed throughout the Caribbean islands and are all found in Puerto Rico. The vegetative parts of the species are similar; however, their conspicuous flowers easily distinguish them. Electrophoresis of seven polymorphic enzymes reveale...... coexist. This suggests that the species may hybridize....

  2. Species Diversity and Growth Forms in Tropical American Palm Communities

    DEFF Research Database (Denmark)

    Balslev, Henrik; Kahn, Francis; Millán, Betty

    2011-01-01

    To advance our understanding of the processes that govern the assembly of palm communities and the local coexistence of numerous palm species, we here synthesize available information in the literature on species diversity and growth-form composition in palm communities across the Americas. Ameri...

  3. Physical layer simulation study for the coexistence of WLAN standards

    Energy Technology Data Exchange (ETDEWEB)

    Howlader, M. K. [Marquette Univ., 222 Haggerty Hall, P. O. Box 1881, Milwaukee, WI 53201 (United States); Keiger, C. [Analysis and Measurement Services Corporation, 9111 Cross Park Drive, Knoxville, TN 37923 (United States); Ewing, P. D. [Oak Ridge National Laboratory, MS-6006, P. O. Box 2008, Oak Ridge, TN 37831 (United States); Govan, T. V. [U.S. Nuclear Regulatory Commission, MS T-10-D20, 11545 Rockville Pike, Rockville, MD 20852 (United States)

    2006-07-01

    This paper presents the results of a study on the performance of wireless local area network (WLAN) devices in the presence of interference from other wireless devices. To understand the coexistence of these wireless protocols, simplified physical-layer-system models were developed for the Bluetooth, Wireless Fidelity (WiFi), and Zigbee devices, all of which operate within the 2.4-GHz frequency band. The performances of these protocols were evaluated using Monte-Carlo simulations under various interference and channel conditions. The channel models considered were basic additive white Gaussian noise (AWGN), Rayleigh fading, and site-specific fading. The study also incorporated the basic modulation schemes, multiple access techniques, and channel allocations of the three protocols. This research is helping the U.S. Nuclear Regulatory Commission (NRC) understand the coexistence issues associated with deploying wireless devices and could prove useful in the development of a technical basis for guidance to address safety-related issues with the implementation of wireless systems in nuclear facilities. (authors)

  4. Death and cannibalism in a seasonal environment facilitate bacterial coexistence.

    Science.gov (United States)

    Rozen, Daniel E; Philippe, Nadège; Arjan de Visser, J; Lenski, Richard E; Schneider, Dominique

    2009-01-01

    Bacterial populations can evolve and adapt to become diverse niche specialists, even in seemingly homogeneous environments. One source of this diversity arises from newly 'constructed' niches that result from the activities of the bacteria themselves. Ecotypes specialized to exploit these distinct niches can subsequently coexist via frequency-dependent interactions. Here, we describe a novel form of niche construction that is based upon differential death and cannibalism, and which evolved during 20 000 generations of experimental evolution in Escherichia coli in a seasonal environment with alternating growth and starvation. In one of 12 populations, two monophyletic ecotypes, S and L, evolved that stably coexist with one another. When grown and then starved in monoculture, the death rate of S exceeds that of L, whereas the reverse is observed in mixed cultures. As shown by experiments and numerical simulations, the competitive advantage of S cells is increased by extending the period of starvation, and this advantage results from their cannibalization of the debris of lysed L cells, which allows the S cells to increase both their growth rate and total cell density. At the molecular level, the polymorphism is associated with divergence in the activity of the alternative sigma factor RpoS, with S cells displaying no detectable activity, while L cells show increased activity relative to the ancestral genotype. Our results extend the repertoire of known cross-feeding mechanisms in microbes to include cannibalism during starvation, and confirm the central roles for niche construction and seasonality in the maintenance of microbial polymorphisms.

  5. Water Resources Management. Coexistence and Conflict in Semiarid Brazil

    Directory of Open Access Journals (Sweden)

    Thiago Ferreira Dias

    2016-01-01

    Full Text Available The paper analyzes water management in the Brazilian semiarid region with emphasis on aspects of coexistence and conflicts over access in rural areas. Experiences of social coexistence in semiarid technologies from the joint to the Brazilian semiarid (ASA and water conflicts from cases of irrigated areas in the states of Ceará and Rio Grande do Norte are explained. For this purpose, we used a qualitative approach through the use of primary and secondary data. The cases provide concrete actions that articulate civil society and the State in favor of the common good. The results indicate that the policy articulated by the ASA there is a governance process in which there are links between the forums of civil society and the interfaces in the planning and implementation of public policies in building public agenda that can bridge the gap between planning, deployment, management and improvement of this policy. In the second case the policy is implemented exclusion and allocation of those communities, placing them on the margins of development, scrapping its links with the territory. The water is not seen from the perspective of the common good and the communities are perceived as an obstacle to “development”. Finally, it outlines themselves from the cases under study, with the idea that limiting access to water in the semiarid region, reflects the precarious welfare and perpetuation of relations of dependency, paternalism and clientelism high proportion of the population rural Brazilian semiarid.

  6. Physical layer simulation study for the coexistence of WLAN standards

    International Nuclear Information System (INIS)

    Howlader, M. K.; Keiger, C.; Ewing, P. D.; Govan, T. V.

    2006-01-01

    This paper presents the results of a study on the performance of wireless local area network (WLAN) devices in the presence of interference from other wireless devices. To understand the coexistence of these wireless protocols, simplified physical-layer-system models were developed for the Bluetooth, Wireless Fidelity (WiFi), and Zigbee devices, all of which operate within the 2.4-GHz frequency band. The performances of these protocols were evaluated using Monte-Carlo simulations under various interference and channel conditions. The channel models considered were basic additive white Gaussian noise (AWGN), Rayleigh fading, and site-specific fading. The study also incorporated the basic modulation schemes, multiple access techniques, and channel allocations of the three protocols. This research is helping the U.S. Nuclear Regulatory Commission (NRC) understand the coexistence issues associated with deploying wireless devices and could prove useful in the development of a technical basis for guidance to address safety-related issues with the implementation of wireless systems in nuclear facilities. (authors)

  7. Explosive synchronization coexists with classical synchronization in the Kuramoto model

    Energy Technology Data Exchange (ETDEWEB)

    Danziger, Michael M., E-mail: michael.danziger@biu.ac.il; Havlin, Shlomo [Department of Physics, Bar-Ilan University, Ramat Gan (Israel); Moskalenko, Olga I.; Kurkin, Semen A. [Faculty of Nonlinear Processes, Saratov State University, Astrakhanskaya, 83, Saratov 410012 (Russian Federation); Saratov State Technical University, Politehnicheskaya, 77, Saratov 410054 (Russian Federation); Zhang, Xiyun [Department of Physics, East China Normal University, Shanghai 200062 (China); Boccaletti, Stefano [CNR-Institute of Complex Systems, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Florence (Italy); The Italian Embassy in Israel, 25 Hamered Street, 68125 Tel Aviv (Israel)

    2016-06-15

    Explosive synchronization has recently been reported in a system of adaptively coupled Kuramoto oscillators, without any conditions on the frequency or degree of the nodes. Here, we find that, in fact, the explosive phase coexists with the standard phase of the Kuramoto oscillators. We determine this by extending the mean-field theory of adaptively coupled oscillators with full coupling to the case with partial coupling of a fraction f. This analysis shows that a metastable region exists for all finite values of f > 0, and therefore explosive synchronization is expected for any perturbation of adaptively coupling added to the standard Kuramoto model. We verify this theory with GPU-accelerated simulations on very large networks (N ∼ 10{sup 6}) and find that, in fact, an explosive transition with hysteresis is observed for all finite couplings. By demonstrating that explosive transitions coexist with standard transitions in the limit of f → 0, we show that this behavior is far more likely to occur naturally than was previously believed.

  8. Wi-Fi Coexistence with Duty Cycled LTE-U

    Directory of Open Access Journals (Sweden)

    Yimin Pang

    2017-01-01

    Full Text Available Coexistence of Wi-Fi and LTE-Unlicensed (LTE-U technologies has drawn significant concern in industry. In this paper, we investigate the Wi-Fi performance in the presence of duty cycle based LTE-U transmission on the same channel. More specifically, one LTE-U cell and one Wi-Fi basic service set (BSS coexist by allowing LTE-U devices to transmit their signals only in predetermined duty cycles. Wi-Fi stations, on the other hand, simply contend the shared channel using the distributed coordination function (DCF protocol without cooperation with the LTE-U system or prior knowledge about the duty cycle period or duty cycle of LTE-U transmission. We define the fairness of the above scheme as the difference between Wi-Fi performance loss ratio (considering a defined reference performance and the LTE-U duty cycle (or function of LTE-U duty cycle. Depending on the interference to noise ratio (INR being above or below −62 dbm, we classify the LTE-U interference as strong or weak and establish mathematical models accordingly. The average throughput and average service time of Wi-Fi are both formulated as functions of Wi-Fi and LTE-U system parameters using probability theory. Lastly, we use the Monte Carlo analysis to demonstrate the fairness of Wi-Fi and LTE-U air time sharing.

  9. Tourette syndrome in a longitudinal perspective. Clinical course of tics and comorbidities, coexisting psychopathologies, phenotypes and predictors.

    Science.gov (United States)

    Groth, Camilla

    2018-04-01

    adolescence and early adulthood. Childhood tics, OCD and ADHD severity were the strongest predictors for future symptoms of the respectively diagnoses. Comorbidities and coexisting psychopathologies were found in 63% at follow-up, whereas 37% had pure TS.
 Conclusion: The clinical course of TS during adolescence was confirmed, with solid evidence, with decline in tics, OCD and ADHD severity. We provide evidence of considerable coexisting psychopathologies requiring clinical support and partial remissions and subthreshold symptoms requiring monitoring and clinical guidance to assist the young adults in promoting a healthy transition into early adulthood. Furthermore we provide predictors for the clinical course of TS to be used in the preventive efforts, early intervention and allocation of resources improving quality of life for the children and their families.

  10. Seasonal dynamics of secondary growth and xylem anatomy in two coexisting Mediterranean Quercus; Dinamica estacional del crecimiento secundario y anatomia del xilema en dos Quercus mediterraneos que coexisten

    Energy Technology Data Exchange (ETDEWEB)

    Albuixech, J.; Camarero, J. J.; Montserrat-Marti, G.

    2012-11-01

    The contribution of secondary growth's patterns and wood anatomy on the coexistence of two species of Quercus (Quercus ilex subsp ballota diffused porous wood and Quercus faginea ring porous wood) were studied in a location with continental Mediterranean climate, which has been studied during two years with contrasted climatology. According to our results secondary growth pattern of Q. faginea is concentrated in the spring, starting before, and responding more than Q. ilex to a rainfall increase during this period. Q. ilex extends wood formation into the fall and late summer growth. Q. ilex growth during the fall and late summer has a greater importance in terms of theoretical hydraulic conductivity than in Q. faginea, which concentrates hydraulic conductivity in spring vessels. Therefore, different response of wood phenology formation and xylem anatomy in both species to the seasonal pattern of precipitation could contribute to explain the coexistence of Q. ilex and Q. faginea. (Author) 48 refs.

  11. The promotion of happiness.

    Science.gov (United States)

    Klamut, Marian Kazimierz

    2002-01-01

    The human mind is capable of creating an internal world--the psychic sphere--including the phenomena characteristic of human nature, such as selfconsciousness, conscious experiences, conceptual thinking, symbolic language, dreams, art, creation of culture, sense of values, interest in the distant past and care about the distant future. According to the exceptionally concordant opinions of the sages and scholars of the East and the West it is just within this internal world that human happiness dwells. Happiness is a state of the spirit which consists in: internal peace, satisfaction with one's life, the joy of life, benevolence and cordiality towards oneself and towards others; sensitivity to the beauty of nature, culture and art; harmonious co-existence with the surroundings. The achievement and experiencing of the states of thus understood happiness depend mainly on ourselves and, similarly to the project of health promotion, require knowledge, willingness and possibilities. Happiness Promotion denotes the commendation and popularizing of a certain definite way of thinking and acting--showing the road which leads to the frequent experiencing of happy moments.

  12. Cognitive radio networks medium access control for coexistence of wireless systems

    CERN Document Server

    Bian, Kaigui; Gao, Bo

    2014-01-01

    This book gives a comprehensive overview of the medium access control (MAC) principles in cognitive radio networks, with a specific focus on how such MAC principles enable different wireless systems to coexist in the same spectrum band and carry out spectrum sharing.  From algorithm design to the latest developments in the standards and spectrum policy, readers will benefit from leading-edge knowledge of how cognitive radio systems coexist and share spectrum resources.  Coverage includes cognitive radio rendezvous, spectrum sharing, channel allocation, coexistence in TV white space, and coexistence of heterogeneous wireless systems.   • Provides a comprehensive reference on medium access control (MAC)-related problems in the design of cognitive radio systems and networks; • Includes detailed analysis of various coexistence problems related to medium access control in cognitive radio networks; • Reveals novel techniques for addressing the challenges of coexistence protocol design at a higher level ...

  13. Coexistence and Competition between Tomicus yunnanensis and T. minor (Coleoptera: Scolytinae in Yunnan Pine

    Directory of Open Access Journals (Sweden)

    Rong Chun Lu

    2012-01-01

    Full Text Available Competition and cooperation between bark beetles, Tomicus yunnanensis Kirkendall and Faccoli and Tomicus minor (Hartig (Coleoptera: Scolytinae were examined when they coexisted together in living Yunnan pine trees (Pinus yunnanensis Franchet in Yunnan province in Southwest China. T. yunnanensis bark beetles were observed to initiate dispersal from pine shoots to trunks in November, while the majority of T. minor begins to transfer in December. T. yunnanensis mainly attacks the top and middle parts of the trunk, whereas T. minor mainly resides in the lower and middle parts of the trunk. The patterns of attack densities of these two species were similar, but with T. yunnanensis colonizing the upper section of the trunk and T. minor the lower trunk. The highest attack density of T. Yunnanensis was 297 egg galleries/m2, and the highest attack density of T. minor was 305 egg galleries/m2. Although there was significant overlap for the same bark areas, the two species generally colonize different areas of the tree, which reduces the intensity of competition for the relatively thin layer of phloem-cambium tissues where the beetles feed and reside.

  14. Coexisting chaotic attractors in a single neuron model with adapting feedback synapse

    International Nuclear Information System (INIS)

    Li Chunguang; Chen Guanrong

    2005-01-01

    In this paper, we consider the nonlinear dynamical behavior of a single neuron model with adapting feedback synapse, and show that chaotic behaviors exist in this model. In some parameter domain, we observe two coexisting chaotic attractors, switching from the coexisting chaotic attractors to a connected chaotic attractor, and then switching back to the two coexisting chaotic attractors. We confirm the chaoticity by simulations with phase plots, waveform plots, and power spectra

  15. CT analysis of lung cancer and coexistent emphysema

    International Nuclear Information System (INIS)

    Noh, Kyung Hee; Chung, Myung Hee; Sung, Mi Sook; Yoo, Won Jong; Son, Kyung Myung; Son, Jung Min; Park, Seog Hee

    2004-01-01

    To evaluate the relation of the location and cell type of lung cancer to the location and degree in coexistent emphysema on high-resolution computed tomography (HRCT) scans. Ninety-eight of 209 lung cancer patients having HRCT scans were retrospectively analyzed to assess the total lung emphysema and peritumoral regional emphysema. Single and primary lung cancers were included. The clinical data, including sex, age, smoking history and the pathologic cancer subtype, were recorded to correlate with the HRCT findings. The lobar distribution, central-peripheral predominance, surrounding parenchymal abnormality for cancer, cephalocaudal predominance, and subtype for emphysema were analyzed on HRCT. Using a CT scoring method, we scored the whole lung emphysema and peritumoral emphysema, and correlated the grading of emphysema with pulmonary functional values. Sixty-nine of 98 patients with lung cancer (71%) had emphysema. Lung cancer with emphysema was significantly higher in men than in women, and was significantly related to smoking. The mean age of cancer patients without emphysema was significantly lower than that of cancer patients with emphysema (68 yrs vs. 61 yrs, p= 0.0006). Emphysema of grade I (0-25%) was found in 52 cases, grade II (25-50%) in 15, and grade III (50-75%) in 2. Total emphysema score was paralleled to peritumoral emphysema score in 64.3%, while the remaining patients had a higher peritumoral emphysema score (grade II or III) than total emphysema score (grade 0 or I). There was no statistical correlation in the developmental location between the emphysema and the lung cancer (significant correlation was only noted in grade II group of total emphysema score). The incidence of non-small cell carcinoma tended to be higher than that of small cell carcinoma in the two groups. The possibility of lung cancer in patients with pulmonary nodule, coexisting emphysema, and especially in elderly patients having a history of smoking must be clarified on HRCT

  16. Coexistence of Obesity and Anemia in Older Mexican Adults.

    Science.gov (United States)

    Samper-Ternent, Rafael; Michaels-Obregon, Alejandra; Wong, Rebeca

    2011-12-08

    INTRODUCTION: Developing countries in Latin America (LA) are experiencing rapid aging as a result of advances in medical interventions. This rapid aging has not occurred with comparable improvements in standards of living. Chronic conditions are becoming highly prevalent while exposure to infectious communicable diseases is very common. This unique situation where communicable and non-communicable diseases coexist in the presence of low socioeconomic status place countries in LA in a unique epidemiological situation. Mexico presents a very good example where the impact of this situation on health warrants further analysis. METHODS: We use data from the Mexican National Health and Nutrition Survey (ENSANut 2006), a cross-sectional study representative of all urban and rural areas of Mexico. A total of 5,605 adults older than 60 years of age with valid values for Body Mass Index and Hemoglobin were analyzed. We first included a descriptive analysis of the coexistence of anemia and obesity by age, gender and characteristics of the living environment. We reported the weighted percentages for each covariate by each of four nutritional condition categories (obese and anemic, only-obese, only-anemic, not obese and not anemic). We used multinomial logit regressions to determine the association of socioeconomic characteristics, health status and the living environment with the presence of the three nutritional condition categories. RESULTS: In the ENSANut cohort 10.3% of older adults are anemic, 25.0% are obese and 2.6% are both anemic and obese. Approximately 62% has neither anemia nor obesity. Within the 38% that fall in the three nutritional condition categories, the co-existence of obesity & anemia appears to be associated with metropolitan area residence, living alone, being male, having relatively high wealth, and reporting two or more chronic health conditions. Analyzing the effect of the covariates to distinguish between outcome categories, living environment, age

  17. Coexistence: Threat to the Performance of Heterogeneous Network

    Science.gov (United States)

    Sharma, Neetu; Kaur, Amanpreet

    2010-11-01

    Wireless technology is gaining broad acceptance as users opt for the freedom that only wireless network can provide. Well-accepted wireless communication technologies generally operate in frequency bands that are shared among several users, often using different RF schemes. This is true in particular for WiFi, Bluetooth, and more recently ZigBee. These all three operate in the unlicensed 2.4 GHz band, also known as ISM band, which has been key to the development of a competitive and innovative market for wireless embedded devices. But, as with any resource held in common, it is crucial that those technologies coexist peacefully to allow each user of the band to fulfill its communication goals. This has led to an increase in wireless devices intended for use in IEEE 802.11 wireless local area networks (WLANs) and wireless personal area networks (WPANs), both of which support operation in the crowded 2.4-GHz industrial, scientific and medical (ISM) band. Despite efforts made by standardization bodies to ensure smooth coexistence it may occur that communication technologies transmitting for instance at very different power levels interfere with each other. In particular, it has been pointed out that ZigBee could potentially experience interference from WiFi traffic given that while both protocols can transmit on the same channel, WiFi transmissions usually occur at much higher power level. In this work, we considered a heterogeneous network and analyzed the impact of coexistence between IEEE 802.15.4 and IEEE 802.11b. To evaluate the performance of this network, measurement and simulation study are conducted and developed in the QualNet Network simulator, version 5.0.Model is analyzed for different placement models or topologies such as Random. Grid & Uniform. Performance is analyzed on the basis of characteristics such as throughput, average jitter and average end to end delay. Here, the impact of varying different antenna gain & shadowing model for this

  18. Adaptive evolution of defense ability leads to diversification of prey species.

    Science.gov (United States)

    Zu, Jian; Wang, Jinliang; Du, Jianqiang

    2014-06-01

    In this paper, by using the adaptive dynamics approach, we investigate how the adaptive evolution of defense ability promotes the diversity of prey species in an initial one-prey-two-predator community. We assume that the prey species can evolve to a safer strategy such that it can reduce the predation risk, but a prey with a high defense ability for one predator may have a low defense ability for the other and vice versa. First, by using the method of critical function analysis, we find that if the trade-off is convex in the vicinity of the evolutionarily singular strategy, then this singular strategy is a continuously stable strategy. However, if the trade-off is weakly concave near the singular strategy and the competition between the two predators is relatively weak, then the singular strategy may be an evolutionary branching point. Second, we find that after the branching has occurred in the prey strategy, if the trade-off curve is globally concave, then the prey species might eventually evolve into two specialists, each caught by only one predator species. However, if the trade-off curve is convex-concave-convex, the prey species might eventually branch into two partial specialists, each being caught by both of the two predators and they can stably coexist on the much longer evolutionary timescale.

  19. Observed fitness may affect niche overlap in competing species via selective social information use.

    Science.gov (United States)

    Loukola, Olli J; Seppänen, Janne-Tuomas; Krams, Indrikis; Torvinen, Satu S; Forsman, Jukka T

    2013-10-01

    Social information transmission is important because it enables horizontal spread of behaviors, not only between conspecifics but also between individuals of different species. Because interspecific social information use is expected to take place among species with similar resource needs, it may have major consequences for the emergence of local adaptations, resource sharing, and community organization. Social information use is expected to be selective, but the conditions promoting it in an interspecific context are not well known. Here, we experimentally test whether pied flycatchers (Ficedula hypoleuca) use the clutch size of great tits (Parus major) in determining the quality of the observed individual and use it as a basis of decision making. We show that pied flycatchers copied or rejected a novel nest site feature preference of great tits experimentally manipulated to exhibit high or low fitness (clutch size), respectively. Our results demonstrate that the social transmission of behaviors across species can be highly selective in response to observed fitness, plausibly making the phenomenon adaptive. In contrast with the current theory of species coexistence, overlap between realized niches of species could dynamically increase or decrease depending on the observed success of surrounding individuals.

  20. Mast fruiting is a frequent strategy in woody species of eastern South America.

    Directory of Open Access Journals (Sweden)

    Natalia Norden

    Full Text Available BACKGROUND: It is thought that mast seeding is a rare reproductive strategy in the tropics, since tropical climates are less variable, and fruit consumers tend to be more generalist in these regions. However, previous tests of this hypothesis were based on only few tropical datasets, and none from tropical South America. Moreover, reproductive strategies have been quantified based on the coefficient of variation of interannual seed production, an index that potentially confounds masting and high interannual variability in seed production. METHODOLOGY/PRINCIPAL FINDINGS: We developed a new approach to model the monthly variability in seed production for 28 tree species, and 20 liana species monitored during 5 years in a tropical forest of Central French Guiana. We found that 23% of the species showed a masting pattern, 54% an annual fruiting pattern, and 23% an irregular fruiting pattern. The majority of masting species were trees (8 out of 11, most of them animal-dispersed. The classification into reproductive strategies based on the coefficient of variation was inconsistent with our results in nearly half of the cases. CONCLUSIONS/SIGNIFICANCE: Our study is the first to clearly evidence the frequency of the masting strategy in a tropical forest community of Eastern South America. The commonness of the masting strategy in tropical plants may promote species coexistence through storage dynamics.

  1. Coexistence of different vacua in the effective quantum field theory and multiple point principle

    International Nuclear Information System (INIS)

    Volovik, G.E.

    2004-01-01

    According to the multiple point principle our Universe in on the coexistence curve of two or more phases of the quantum vacuum. The coexistence of different quantum vacua can be regulated by the exchange of the global fermionic charges between the vacua. If the coexistence is regulated by the baryonic charge, all the coexisting vacua exhibit the baryonic asymmetry. Due to the exchange of the baryonic charge between the vacuum and matter which occurs above the electroweak transition, the baryonic asymmetry of the vacuum induces the baryonic asymmetry of matter in our Standard-Model phase of the quantum vacuum [ru

  2. Byssus attachment strength of two mytilids in mono-specific and mixed-species mussel beds.

    Science.gov (United States)

    Babarro, Jose M F; Comeau, Luc A

    2014-09-01

    The mussel Xenostrobus securis is endemic to the brackish waters of New Zealand and Australia, but has successfully invaded the inner Galician Rías of NW Spain, where it coexists with the indigenous mussel Mytilus galloprovincialis. In this laboratory study, the plasticity of the byssus attachment strength of two mytilids was compared by manipulating substratum, salinity, and bed assembly. M. galloprovincialis showed stronger byssus detachment strength than X. securis, despite lower byssus coverage. Both species responded similarly to the substratum, with substantially lower byssus strength on methacrylate, which offered the lowest surface free energy. Byssus detachment values for M. galloprovincialis were lower at lower salinity. In mixed beds, a number of mussels moved upwards, eventually colonising the upper layers of the assemblage. This behaviour increased byssus strength but only for X. securis. X. securis is adapted to a wide spectrum of abiotic conditions, a trait that may promote its dissemination within estuarine environments.

  3. Coexistence and transition between shear zones in slow granular flows.

    Science.gov (United States)

    Moosavi, Robabeh; Shaebani, M Reza; Maleki, Maniya; Török, János; Wolf, Dietrich E; Losert, Wolfgang

    2013-10-04

    We report experiments on slow granular flows in a split-bottom Couette cell that show novel strain localization features. Nontrivial flow profiles have been observed which are shown to be the consequence of simultaneous formation of shear zones in the bulk and at the boundaries. The fluctuating band model based on a minimization principle can be fitted to the experiments over a large variation of morphology and filling height with one single fit parameter, the relative friction coefficient μ(rel) between wall and bulk. The possibility of multiple shear zone formation is controlled by μ(rel). Moreover, we observe that the symmetry of an initial state, with coexisting shear zones at both side walls, breaks spontaneously below a threshold value of the shear velocity. A dynamical transition between two asymmetric flow states happens over a characteristic time scale which depends on the shear strength.

  4. Coexistence of bilateral first and second branchial arch anomalies

    Science.gov (United States)

    Thakur, J S; Shekar, Vidya; Saluja, Manika; Mohindroo, N K

    2013-01-01

    Branchial arch anomalies are one of the most common congenital anomalies that are usually unilateral and bilateral presentation is rare. The simultaneous presence of bilateral second branchial arch anomalies along with bilateral first arch anomalies is extremely rare, with only three such cases reported in the literature. We present two non-syndromic cases of coexisting bilateral first and second arch anomalies. Developmental anomalies of the branchial apparatus account for 17% of all paediatric cervical masses and are the most common type of congenital cervical mass. They usually present in the paediatric age group. About 96–97% of these anomalies are unilateral. Bilateral presentation is seen in 2–3% having a strong familial association. Congenital syndromes also have been associated with first and second branchial arch anomalies. Thorough clinical examination and investigations should be done to rule out these syndromes. PMID:23580675

  5. Liquid-vapor coexistence by molecular dynamics simulation

    International Nuclear Information System (INIS)

    Baranyai, Andras; Cummings, Peter T.

    2000-01-01

    We present a simple and consistent molecular dynamics algorithm for determining the equilibrium properties of a bulk liquid and its coexisting vapor phase. The simulation follows the dynamics of the two systems simultaneously while maintaining the volume and the number of particles of the composite system fixed. The thermostat can constrain either the total energy or the temperature at a desired value. Division of the extensive properties between the two phases is governed by the difference of the corresponding intensive state variables. Particle numbers are continuous variables and vary only in virtual sense, i.e., the real sizes of the two systems are the same and do not change during the course of the simulation. Calculation of the chemical potential is separate from the dynamics; thus, one can replace the particle exchange step with other method if it improves the efficiency of the code. (c) 2000 American Institute of Physics

  6. From Localized Scleroderma to Systemic Sclerosis: Coexistence or Possible Evolution.

    Science.gov (United States)

    Dilia, Giuggioli; Michele, Colaci; Emanuele, Cocchiara; Amelia, Spinella; Federica, Lumetti; Clodoveo, Ferri

    2018-01-01

    Systemic sclerosis (SSc) and localized scleroderma (LoS) are two different diseases that may share some features. We evaluated the relationship between SSc and LoS in our case series of SSc patients. We analysed the clinical records of 330 SSc patients, in order to find the eventual occurrence of both the two diseases. Eight (2.4%) female patients presented both the two diagnoses in their clinical histories. Six developed LoS prior to SSc; in 4/6 cases, the presence of autoantibodies was observed before SSc diagnosis. Overall, the median time interval between LoS and SSc diagnosis was 18 (range 0-156) months. LoS and SSc are two distinct clinical entities that may coexist. Moreover, as anecdotally reported in pediatric populations, we suggested the possible development of SSc in adult patients with LoS, particularly in presence of Raynaud's phenomenon or antinuclear antibodies before the SSc onset.

  7. Do Electrons and Ions Coexist in an EBIT?

    International Nuclear Information System (INIS)

    Lapierre, A.; Crespo Lopez-Urrutia, J.R.; Braun, J.; Brenner, G.; Bruhns, H.; Fischer, D.; Gonzalez Martinez, A.J.; Mironov, V.; Osborne, C. J.; Sikler, G.; Soria Orts, R.; Tawara, H.; Ullrich, J.; Yamazaki, Y.

    2005-01-01

    Detailed analysis of an extended exponential tail observed in the decay curve of the 2P3/2-2P1/2 magnetic dipole (M1) transition in boron-like Ar13+ provides evidence that electrons and ions might coexist in the same spatial region in the Heidelberg Electron Beam Ion Trap (HD-EBIT). On this basis, new trapping-cooling-recombination schemes for positron-antiproton plasmas are envisioned, integrated in a magnetic bottle configuration that should be able to trap the subsequently formed recombined cold antihydrogen. Moreover, the EBIT configuration, providing excellent spectroscopic access to the trapping region via seven view ports is shown to be well suited for performing precision spectroscopy of antiprotonic ions. Those might be generated either by recombination of antiprotons with neutral gas atoms or through radiative recombination and state-selective dielectronic-recombination-like processes with highly charged ions produced and stored in the EBIT simultaneously in a nested trap configuration

  8. [Coexistence of autoimmune polyglandular syndrome type 3 with diabetes insipidus].

    Science.gov (United States)

    Krysiak, Robert; Okopień, Bogusław

    2015-01-01

    Autoimmune polyglandular syndromes are conditions characterized by the combination of two or more organ-specific disorders. The underestimation oftheir real frequency probable results from physicians' inadequate knowledge of these clinical entities and sometimes their atypical clinical presentation. Because they comprise a wide spectrum of autoimmune disorders, autoimmune polyglandular syndromes are divided into four types, among which type-3 is the most common one. In this article, we report the case of a young female, initially diagnosed with diabetes mellitus who several years later developed full-blown autoimmune polyglandular syndrome type 3 consisting of autoimmune thyroid disorder and latent autoimmune diabetes in adults.The discussed case suggests that in selected patients diabetes insipidus may coexist with autoimmune endocrinopathies and nonendocrine autoimmunopathies, as well as that in some patients idiopathic diabetes insipidus may be secondary to lymphocytic infiltration and destruction of the hypothalamic supraoptic and paraventricular nuclei and/or the supraoptic-hypophyseal tract

  9. Coexistence of negative photoconductivity and hysteresis in semiconducting graphene

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, Shendong; Tang, Nujiang; Chen, Zhuo, E-mail: zchen@nju.edu.cn [School of Physics, National Laboratory of Solid State Microstructures, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, No. 22 Hankou Road, Nanjing, Jiangsu, 210093 (China); Chen, Yan; Xia, Yidong [Department of Materials Science and Engineering, National Laboratory of Solid State Microstructures, and Collaborative Innovation Center of Advanced Microstructures, No. 22 Hankou Road, Nanjing University, Nanjing, Jiangsu, 210093 (China); Xu, Xiaoyong; Hu, Jingguo, E-mail: jghu@yzu.edu.cn [School of Physics Science and Technology, Yangzhou University, No. 180 Siwangting Road, Yangzhou, Jiangsu, 225002 (China)

    2016-04-15

    Solution-processed graphene quantum dots (GQDs) possess a moderate bandgap, which make them a promising candidate for optoelectronics devices. However, negative photoconductivity (NPC) and hysteresis that happen in the photoelectric conversion process could be harmful to performance of the GQDs-based devices. So far, their origins and relations have remained elusive. Here, we investigate experimentally the origins of the NPC and hysteresis in GQDs. By comparing the hysteresis and photoconductance of GQDs under different relative humidity conditions, we are able to demonstrate that NPC and hysteresis coexist in GQDs and both are attributed to the carrier trapping effect of surface adsorbed moisture. We also demonstrate that GQDs could exhibit positive photoconductivity with three-order-of-magnitude reduction of hysteresis after a drying process and a subsequent encapsulation. Considering the pervasive moisture adsorption, our results may pave the way for a commercialization of semiconducting graphene-based and diverse solution-based optoelectronic devices.

  10. The Coexistence of Coeliac Disease, Psoriasis and Vitiligo

    Directory of Open Access Journals (Sweden)

    Sevgi Akarsu

    2010-06-01

    Full Text Available It has been defined that coeliac disease is associated with most of the autoimmune diseases including psoriasis and vitiligo. Here, a 26-year-old woman who was diagnosed palmoplantar pustular psoriasis and already had coeliac disease and vitiligo is reported. According to our opinions, this is the first report describing the development of these three disorders in one patient, even though vitiligo, psoriasis and coeliac disease are common disorders, and the coexistence of the two of them has been previously reported in the literature. This case has been presented to emphasize the importance of considering and inquiring the possible coeliac disease in chronic and autoimmune dermatoses, although psoriasis and vitiligo may have coincidental associations with coeliac disease.

  11. Coexistence of carcinoma and tuberculosis in one breast

    Directory of Open Access Journals (Sweden)

    Dalal Neha

    2008-03-01

    Full Text Available Abstract Background The coexistence of breast cancer and tuberculosis is very rare. This can create a dilemma in the diagnosis and treatment as there are no pathognomonic symptoms or signs to distinguish both diseases. Case presentation A female patient was seen in the breast clinic for a right breast lump. Clinical examination and investigation confirmed cancer and tuberculosis of the right breast. She underwent right mastectomy and axillary clearance and received chemo and radiotherapy. Unfortunately, she died of wide spread metastases. Conclusion The simultaneous occurrence of these two major illnesses in the breast can lead to many problems regarding diagnosis and treatment. Though rare, surgeons, pathologists and radiologists should be aware of such condition.

  12. Coexistence of negative photoconductivity and hysteresis in semiconducting graphene

    International Nuclear Information System (INIS)

    Zhuang, Shendong; Tang, Nujiang; Chen, Zhuo; Chen, Yan; Xia, Yidong; Xu, Xiaoyong; Hu, Jingguo

    2016-01-01

    Solution-processed graphene quantum dots (GQDs) possess a moderate bandgap, which make them a promising candidate for optoelectronics devices. However, negative photoconductivity (NPC) and hysteresis that happen in the photoelectric conversion process could be harmful to performance of the GQDs-based devices. So far, their origins and relations have remained elusive. Here, we investigate experimentally the origins of the NPC and hysteresis in GQDs. By comparing the hysteresis and photoconductance of GQDs under different relative humidity conditions, we are able to demonstrate that NPC and hysteresis coexist in GQDs and both are attributed to the carrier trapping effect of surface adsorbed moisture. We also demonstrate that GQDs could exhibit positive photoconductivity with three-order-of-magnitude reduction of hysteresis after a drying process and a subsequent encapsulation. Considering the pervasive moisture adsorption, our results may pave the way for a commercialization of semiconducting graphene-based and diverse solution-based optoelectronic devices.

  13. CT imaging of coexisting pulmonary tuberculosis and lung cancer

    International Nuclear Information System (INIS)

    Lv Yan; Xie Ruming; Zhou Xinhua; Zhou Zhen; Xu Jinping; He Wei; Guo Lifang; Ning Fenggang

    2013-01-01

    Objective: To study the CT characteristics of coexisting pulmonary tuberculosis and lung cancer. Methods: One hundred and four patients of coexisting pulmonary tuberculosis and lung cancer proved by histology, cytology or clinical underwent CT examination. All patients were divided into two groups, group Ⅰ were the patients with the lung cancer after tuberculosis or both found simultaneously (group Ⅰ a with peripheral lung cancer and group Ⅰ b with central lung cancer), group Ⅱ with tuberculosis during lung cancer chemotherapy (group Ⅱ a with peripheral lung cancer and group Ⅱ b with central lung cancer). Imaging characteristics of tuberculosis and lung cancer were compared. χ"2 test and t test were used for the statistical analysis. Results: Of 104 patients, there were 92 patients (88.5%) in group Ⅰ and 12 patients (11.5%) in group Ⅱ. Seventy patients (76.1%) of lung cancer and tuberculosis were located in the same lobe and 22 patients (23.9%) in the different lobes in group Ⅰ. There was no significant difference in distribution of tuberculosis between group Ⅰ and group Ⅱ (χ"2 = 4.302, P = 0.507). The fibrous stripes, nodules of calcification and pleural adhesion of tuberculosis were statistically significant between the two groups (χ"2 = 22.737, 15.193, 27.792, P < 0.05). There were 33 central lung cancers and 71 peripheral lung cancers. In group Ⅰ a (64 patients of peripheral lung cancers), 39 patients (60.9%) had typical manifestations and most of the lesions were ≥ 3 cm (n = 49, 76.6%), solid lesions showed variable enhancement. Conclusions: Secondary tuberculosis during lung cancer chemotherapy has the same CT characteristics with the common active tuberculosis. The morphology, enhancement pattern of lesion and follow-up are helpful for the diagnosis of lung cancer after tuberculosis. (authors)

  14. Coexisting anxiety and depressive symptoms in patients with heart failure.

    Science.gov (United States)

    Dekker, Rebecca L; Lennie, Terry A; Doering, Lynn V; Chung, Misook L; Wu, Jia-Rong; Moser, Debra K

    2014-04-01

    Among patients with heart failure (HF), anxiety symptoms may co-exist with depressive symptoms. However, the extent of overlap and risk factors for anxiety symptoms have not been thoroughly described. The aim of this study was to describe the coexistence of anxiety and depressive symptoms, and to determine the predictors of anxiety symptoms in patients with HF. The sample consisted of 556 outpatients with HF (34% female, 62±12 years, 54% New York Heart Association (NYHA) class III/IV) enrolled in a multicenter HF quality of life registry. Anxiety symptoms were assessed with the Brief Symptom Inventory-anxiety subscale. Depressive symptoms were measured with the Beck Depression Inventory-II (BDI). We used a cut-point of 0.35 to categorize patients as having anxiety symptoms or no anxiety symptoms. Logistic regression was used to determine whether age, gender, minority status, educational level, functional status, comorbidities, depressive symptoms, and antidepressant use were predictors of anxiety symptoms. One-third of patients had both depressive and anxiety symptoms. There was a dose-response relationship between depressive symptoms and anxiety symptoms; higher levels of depressive symptoms were associated with a higher level of anxiety symptoms. Younger age (odds ratio (OR)= 0.97, p=0.004, 95% confidence interval (CI) 0.95-0.99) and depressive symptoms (OR =1.25, panxiety symptoms. Patients with HF and depressive symptoms are at high risk for experiencing anxiety symptoms. Clinicians should assess these patients for comorbid anxiety symptoms. Research is needed to test interventions for both depressive and anxiety symptoms.

  15. Coexisting cycles in a class of 3-D discrete maps

    Directory of Open Access Journals (Sweden)

    Agliari Anna

    2012-08-01

    Full Text Available In this paper we consider the class of three-dimensional discrete maps M (x, y, z = [φ(y, φ(z, φ(x], where φ : ℝ → ℝ is an endomorphism. We show that all the cycles of the 3-D map M can be obtained by those of φ(x, as well as their local bifurcations. In particular we obtain that any local bifurcation is of co-dimension 3, that is three eigenvalues cross simultaneously the unit circle. As the map M exhibits coexistence of cycles when φ(x has a cycle of period n ≥ 2, making use of the Myrberg map as endomorphism, we describe the structure of the basins of attraction of the attractors of M and we study the effect of the flip bifurcation of a fixed point. Dans ce papier nous considérons la classe des applications trois-dimensionnelles discrètes M (x, y, z = [φ(y, φ(z, φ(x], où φ : ℝ → ℝ est un endomorphisme. Nous montrons que tous les cycles de l’application 3-D M peuvent être obtenus par ceux de φ(x, ainsi que leurs bifurcations locales. En particulier, nous obtenons que toute bifurcation locale est de co-dimension 3, c’est-à-dire que trois valeurs propres franchissent simultanément le cercle unité. Comme l’application M exhibe une coexistence de cycles lorsque φ(x a un cycle de période n ≥ 2, en utilisant l’application de Myrberg comme endomorphisme, nous décrivons la structure des bassins d’attraction des attracteurs de M et nous étudions les effets d’une bifurcation de doublement de période d’un point fixe.

  16. Coexistence of risk behaviors for being overweight among Brazilian adolescents.

    Science.gov (United States)

    Ferreira, Nathália Luíza; Claro, Rafael Moreira; Mingoti, Sueli Aparecida; Lopes, Aline Cristine Souza

    2017-07-01

    This study aimed to evaluate the magnitude of and the factors associated with the coexistence of risk behaviors for being overweight among Brazilian adolescents. This is a cross-sectional study with a representative sample of adolescents (mostly aged 13-15years) enrolled from public and private schools of Brazil in 2012. The co-occurring sedentary behavior and inadequate food consumption (regular intake of sugary and fried foods, and irregular consumption of fruits and vegetables-FV) was estimated using a Venn diagram. Sociodemographic, familial, and behavioral factors associated with the number of risk behaviors for being overweight were identified using an ordinal logistic regression analysis. Sedentary behavior was observed in 62.0% of adolescents. Regular intake of sugary or fried food was observed in 55.3% and 23.5% of adolescents, respectively, with 51.9% having an inadequate intake of FV. At least one risk behavior was reported in >90.0% of adolescents; 6.1% reported all 4. Being female, having a higher maternal education level, attending private school, not having breakfast or meals with parents regularly, eat watching television, and not practicing weekly leisure time physical activity were associated with an increased chance of having multiple risk behaviors. This study observed a high prevalence of coexisting of risk behaviors, which was associated with sociodemographic, familial, and behavioral factors. These findings may contribute to a clearer understanding of the associations between different behaviors among adolescents, and may be used to improve public health surveillance and to develop strategies that address multiple behaviors, in order to prevent overweight among adolescents. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Disappearance of neutron magic numbers and deformation coexistence

    International Nuclear Information System (INIS)

    Kimura, Masaaki

    2014-01-01

    The disappearance of N=8, 20 and 28 magic numbers in the neutron excess nuclei is a representative example of the special features of the unstable nuclei. In this lecture of summer school, the problems of the magic number disappearance are presented. And the appearance of the deformation coexistence and the anomalous cluster structure come into the problem with them. At the begging the Antisymmetrized Molecular Dynamic (AMD) framework is explained with finite range two body central force and Gorgny DIS force composed of the zero range spin-orbit force and saturability. Island of inversion is explained in the nuclear chart shown in the figure and energy curves of the nuclei near 32 Mg and the excitation level schemes of 32 Mg are shown in the serial figures. As one of the extreme example of the nuclear structure the deformation of 19 F is picked up. The level schemes and structures of 21 F are shown as well. The molecule-like structure in the island of inversion is clear. The rotational band energy of fluorine isotopes are shown up to 29 F. As a new deformation area, disappearance of N=28 magic number is in the spotlight recently. In this case it is characteristic properties that the parities of the orbits to form the gap must be the same but the angular momenta should be different by 2. According to the AMD research, it is shown that deformations of prolate, three-axis asymmetric and oblate characters coexist in the very low excitation energy region accompanying the disappearance of N=28 gap. The concept of magic numbers has been very fundamental in nuclear physics since the success of shell model. At present its disappearance in the unstable nuclei is one of the most challenging problems in the understanding of the nuclear many body problems. (S. Funahashi)

  18. A nucleon-pair and boson coexistent description of nuclei

    Science.gov (United States)

    Dai, Lianrong; Pan, Feng; Draayer, J. P.

    2017-07-01

    We study a mixture of s-bosons and like-nucleon pairs with the standard pairing interaction outside an inert core. Competition between the nucleon-pairs and s-bosons is investigated in this scenario. The robustness of the BCS-BEC coexistence and crossover phenomena are examined through an analysis of pf-shell nuclei with realistic single-particle energies, in which two configurations with Pauli blocking of nucleon-pair orbits due to the formation of the s-bosons is taken into account. When the nucleon-pair orbits are considered to be independent of the s-bosons, the BCS-BEC crossover becomes smooth, with the number of the s-bosons noticeably more than that of the nucleon-pairs near the half-shell point, a feature that is demonstrated in the pf-shell for several values of the standard pairing interaction strength. As a further test of the robustness of the BCS-BEC coexistence and crossover phenomena in nuclei, results are given for values of even-even 102-130Sn with 100Sn taken as a core and valence neutron pairs confined within the 1d 5/2, 0g 7/2, 1d 3/2, 2s 1/2, 1h 11/2 orbits in the nucleon-pair orbit and the s-boson independent approximation. The results indicate that the B(E2) values are reproduced well. Supported by National Natural Science Foundation of China (11375080, 11675071), the U.S. National Science Foundation (OCI-0904874 and ACI-1516338), U. S. Department of Energy (DE-SC0005248), the Southeastern Universities Research Association, the China-U. S. Theory Institute for Physics with Exotic Nuclei (CUSTIPEN) (DE-SC0009971), and the LSU-LNNU joint research program (9961) is acknowledged

  19. Nutritional Recommendation Should Promote Sustainability.

    Science.gov (United States)

    Reber, Robert J.

    1991-01-01

    Any process or event that disrupts the flow of nutrients and energy becomes a nutrition problem. Nutritionists should promote practices that protect the integrity, stability, and beauty of the land community (soil, water, air, all biological species). (Author)

  20. Seasonal movements of wildlife and livestock in a heterogenous pastoral landscape: Implications for coexistence and community based conservation

    Directory of Open Access Journals (Sweden)

    Peter Tyrrell

    2017-10-01

    Full Text Available Rangelands across the world are home to millions of pastoral people and vast wildlife populations, which create a complex landscape for conservation. Community based conservation has been used to promote human-wildlife coexistence on pastoral lands, protecting wildlife outside of official protected areas. With the spread of community based conservation within the rangelands there is a need for more information on successful management practices. This study provides an example of this in the South Rift, Kenya, where seasonal movements of pastoralists aid coexistence. We used Density Surface Modelling (DSM, a novel tool for conservation managers in the rangelands, to predict wildlife and livestock abundance across the landscape and seasons. Wildlife grazers, zebra (Equus burchelli and wildebeest (Connochaetes taurinus, follow expected metabolic patterns, feeding on short grass outside the conservation area in the wet season, before returning to the taller-lower quality grazing in the conservation areas during the drought. Browsing wildlife, impala (Aepyceros melampus and Grant’s gazelle (Nanger granti, move from open grassland and bushland areas into thicker, denser browse as the seasons progress towards the drought. Livestock, both shoats (Ovis aries, and Capra aegagrus hircus and cattle (Bos indicus, are managed by community grazing committees, who enforce a grazing plan that creates spatial–temporal separation between wildlife and livestock. They exploit the high-quality grazing in the livestock area during the wet season while conserving pasture in the conservation area, which is utilized only as forage is depleted. This ensures that wildlife has access to a diverse resource base across all seasons and potentially reduces competition, allowing for a diverse and abundant wildlife community to coexist with livestock. This highlights the importance of the presence and maintenance of spatial and temporal heterogeneity of forage resources

  1. Coexistence of hypothyroidism with inflammatory arthritis is associated with cardiovascular disease in women.

    NARCIS (Netherlands)

    Raterman, H.G.; Nielen, M.M.J.; Peters, M.J.L.; Verheij, R.A.; Nurmohamed, M.T.; Schellevis, F.G.

    2012-01-01

    OBJECTIVES: Hypothyroidism and inflammatory arthritis tend to coexist, but data on this association are sparse. In terms of cardiovascular risk, this association may have clinical relevance as this coexistence may carry an additional cardiovascular risk. This study calculates, first, the prevalence

  2. The principle(s) of co-existence in Europe: Social, economic and legal avenues

    NARCIS (Netherlands)

    Purnhagen, K.; Wesseler, J.H.H.

    2015-01-01

    The European policy of coexistence follows a number of well-established social, economic and legal principles. Applying these principles in practice has resulted in a complex “rag rug” of coexistence policies in Europe. This rag rug makes enforcement of these principles difficult, at times even

  3. The role of multimodal signals in species recognition between tree-killing bark beetles in a narrow sympatric zone.

    Science.gov (United States)

    Deepa S. Pureswaran; Richard W. Hofstetter; Brian Sullivan; Kristen A. Potter

    2016-01-01

    When related species coexist, selection pressure should favor evolution of species recognition mechanisms to prevent interspecific pairing and wasteful reproductive encounters. We investigated the potential role of pheromone and acoustic signals in species recognition between two species of tree-killing bark beetles, the southern pine beetle, Dendroctonus frontalis...

  4. Morphological similarity and ecological overlap in two rotifer species.

    Science.gov (United States)

    Gabaldón, Carmen; Montero-Pau, Javier; Serra, Manuel; Carmona, María José

    2013-01-01

    Co-occurrence of cryptic species raises theoretically relevant questions regarding their coexistence and ecological similarity. Given their great morphological similitude and close phylogenetic relationship (i.e., niche retention), these species will have similar ecological requirements and are expected to have strong competitive interactions. This raises the problem of finding the mechanisms that may explain the coexistence of cryptic species and challenges the conventional view of coexistence based on niche differentiation. The cryptic species complex of the rotifer Brachionus plicatilis is an excellent model to study these questions and to test hypotheses regarding ecological differentiation. Rotifer species within this complex are filtering zooplankters commonly found inhabiting the same ponds across the Iberian Peninsula and exhibit an extremely similar morphology-some of them being even virtually identical. Here, we explore whether subtle differences in body size and morphology translate into ecological differentiation by comparing two extremely morphologically similar species belonging to this complex: B. plicatilis and B. manjavacas. We focus on three key ecological features related to body size: (1) functional response, expressed by clearance rates; (2) tolerance to starvation, measured by growth and reproduction; and (3) vulnerability to copepod predation, measured by the number of preyed upon neonates. No major differences between B. plicatilis and B. manjavacas were found in the response to these features. Our results demonstrate the existence of a substantial niche overlap, suggesting that the subtle size differences between these two cryptic species are not sufficient to explain their coexistence. This lack of evidence for ecological differentiation in the studied biotic niche features is in agreement with the phylogenetic limiting similarity hypothesis but requires a mechanistic explanation of the coexistence of these species not based on

  5. Morphological similarity and ecological overlap in two rotifer species.

    Directory of Open Access Journals (Sweden)

    Carmen Gabaldón

    Full Text Available Co-occurrence of cryptic species raises theoretically relevant questions regarding their coexistence and ecological similarity. Given their great morphological similitude and close phylogenetic relationship (i.e., niche retention, these species will have similar ecological requirements and are expected to have strong competitive interactions. This raises the problem of finding the mechanisms that may explain the coexistence of cryptic species and challenges the conventional view of coexistence based on niche differentiation. The cryptic species complex of the rotifer Brachionus plicatilis is an excellent model to study these questions and to test hypotheses regarding ecological differentiation. Rotifer species within this complex are filtering zooplankters commonly found inhabiting the same ponds across the Iberian Peninsula and exhibit an extremely similar morphology-some of them being even virtually identical. Here, we explore whether subtle differences in body size and morphology translate into ecological differentiation by comparing two extremely morphologically similar species belonging to this complex: B. plicatilis and B. manjavacas. We focus on three key ecological features related to body size: (1 functional response, expressed by clearance rates; (2 tolerance to starvation, measured by growth and reproduction; and (3 vulnerability to copepod predation, measured by the number of preyed upon neonates. No major differences between B. plicatilis and B. manjavacas were found in the response to these features. Our results demonstrate the existence of a substantial niche overlap, suggesting that the subtle size differences between these two cryptic species are not sufficient to explain their coexistence. This lack of evidence for ecological differentiation in the studied biotic niche features is in agreement with the phylogenetic limiting similarity hypothesis but requires a mechanistic explanation of the coexistence of these species not

  6. Effects of 'target' plant species body size on neighbourhood species richness and composition in old-field vegetation.

    Directory of Open Access Journals (Sweden)

    Brandon S Schamp

    Full Text Available Competition is generally regarded as an important force in organizing the structure of vegetation, and evidence from several experimental studies of species mixtures suggests that larger mature plant size elicits a competitive advantage. However, these findings are at odds with the fact that large and small plant species generally coexist, and relatively smaller species are more common in virtually all plant communities. Here, we use replicates of ten relatively large old-field plant species to explore the competitive impact of target individual size on their surrounding neighbourhoods compared to nearby neighbourhoods of the same size that are not centred by a large target individual. While target individuals of the largest of our test species, Centaurea jacea L., had a strong impact on neighbouring species, in general, target species size was a weak predictor of the number of other resident species growing within its immediate neighbourhood, as well as the number of resident species that were reproductive. Thus, the presence of a large competitor did not restrict the ability of neighbouring species to reproduce. Lastly, target species size did not have any impact on the species size structure of neighbouring species; i.e. they did not restrict smaller, supposedly poorer competitors, from growing and reproducing close by. Taken together, these results provide no support for a size-advantage in competition restricting local species richness or the ability of small species to coexist and successfully reproduce in the immediate neighbourhood of a large species.

  7. Resource partitioning between sympatric starfish from tropical unconsolidated substrate: Implications for coexistence and top-down control on benthic prey

    Science.gov (United States)

    Fernandez, Wellington S.; Dias, Gustavo M.; Majer, Alessandra P.; Delboni, Cynthia G.; Denadai, Marcia R.; Turra, Alexander

    2017-09-01

    Starfish are important predators that may shape rocky shore communities, but their ecological role in unconsolidated substrate communities is still poorly known. We assessed the feeding niche overlap of two sympatric starfish, Astropecten marginatus and Luidia senegalensis, from the shallow subtidal zone in southeastern Brazil. During one year, we conducted monthly samples to compare diet composition, abundance and frequency of occurrence of each food item between species. With 24 of the 34 food items identified in this study consumed by both species, they exhibited generalist behaviors, with a more diverse diet during the warm periods, when the main prey items were abundant. However, A. marginatus showed more variation in abundance of prey consumed over time than L. senegalensis. The diet of A. marginatus consisted primarily of the bivalve Tivela mactroides and L. senegalensis of the bivalve Mulinia cleryana. The size of T. mactroides was positively correlated to the size of A. marginatus, while only small-sized individuals of L. senegalensis consumed this item, the most abundant prey in the area and an important food resource for local the community. The large quantity and variety of items consumed by both species support the structuring role of starfish in subtidal unconsolidated substrate communities, exerting a generalist top-down control, primarily on dominant bivalve populations. Temporal variation in the availability of the main prey may change how selective are both species. The differences in prey composition between species and the ontogenetic differences in prey selectivity by L. senegalensis may attenuate interspecific competition, facilitating their coexistence.

  8. Health Promotion

    DEFF Research Database (Denmark)

    Povlsen, Lene; Borup, I.

    2015-01-01

    and Adolescent Health Promotion', Salutogenesis - from theory to practice' and Health, Stress and Coping'. More than half of all doctoral theses undertaken at NHV during these years had health promotion as their theme. As a derivative, the Nordic Health Promotion Research Network (NHPRN) was established in 2007......In 1953 when the Nordic School of Public Health was founded, the aim of public health programmes was disease prevention more than health promotion. This was not unusual, since at this time health usually was seen as the opposite of disease and illness. However, with the Ottawa Charter of 1986......, the World Health Organization made a crucial change to view health not as a goal in itself but as the means to a full life. In this way, health promotion became a first priority and fundamental action for the modern society. This insight eventually reached NHV and in 2002 - 50 years after the foundation...

  9. Resource partitioning by evergreen and deciduous species in a tropical dry forest.

    Science.gov (United States)

    Álvarez-Yépiz, Juan C; Búrquez, Alberto; Martínez-Yrízar, Angelina; Teece, Mark; Yépez, Enrico A; Dovciak, Martin

    2017-02-01

    Niche differentiation can lead to coexistence of plant species by partitioning limiting resources. Light partitioning promotes niche differentiation in tropical humid forests, but it is unclear how niche partitioning occurs in tropical dry forests where both light and soil resources can be limiting. We studied the adult niche of four dominant evergreen (cycad, palm) and drought-deciduous (legume, oak) species co-occurring along environmental gradients. We analyzed light intensity and soil fertility effects on key functional traits related to plant carbon and water economy, how these traits determine species' functional strategies, and how these strategies relate to relative species abundance and spatial patterns. Light intensity was negatively associated with a key trait linked to plant water economy (leaf δ 13 C, a proxy for long-term water-use efficiency-WUE), while soil fertility was negatively associated with a key trait for plant carbon economy (LNC, leaf nitrogen content). Evergreens were highly sclerophyllous and displayed an efficient water economy but poor carbon economy, in agreement with a conservative resource-use strategy (i.e., high WUE but low LNC, photosynthetic rates and stature). Conversely, deciduous species, with an efficient carbon economy but poor water economy, exhibited an exploitative resource-use strategy (i.e., high LNC, photosynthetic rates and stature, but low WUE). Evergreen and deciduous species segregated spatially, particularly at fine-scales, as expected for species with different resource-use strategies. The efficient water economy of evergreens was related to their higher relative abundance, suggesting a functional advantage against drought-deciduous species in water-limited environments within seasonally dry tropical forests.

  10. Two Different Template Replicators Coexisting in the Same Protocell: Stochastic Simulation of an Extended Chemoton Model

    Science.gov (United States)

    Zachar, István; Fedor, Anna; Szathmáry, Eörs

    2011-01-01

    The simulation of complex biochemical systems, consisting of intertwined subsystems, is a challenging task in computational biology. The complex biochemical organization of the cell is effectively modeled by the minimal cell model called chemoton, proposed by Gánti. Since the chemoton is a system consisting of a large but fixed number of interacting molecular species, it can effectively be implemented in a process algebra-based language such as the BlenX programming language. The stochastic model behaves comparably to previous continuous deterministic models of the chemoton. Additionally to the well-known chemoton, we also implemented an extended version with two competing template cycles. The new insight from our study is that the coupling of reactions in the chemoton ensures that these templates coexist providing an alternative solution to Eigen's paradox. Our technical innovation involves the introduction of a two-state switch to control cell growth and division, thus providing an example for hybrid methods in BlenX. Further developments to the BlenX language are suggested in the Appendix. PMID:21818258

  11. Two different template replicators coexisting in the same protocell: stochastic simulation of an extended chemoton model.

    Science.gov (United States)

    Zachar, István; Fedor, Anna; Szathmáry, Eörs

    2011-01-01

    The simulation of complex biochemical systems, consisting of intertwined subsystems, is a challenging task in computational biology. The complex biochemical organization of the cell is effectively modeled by the minimal cell model called chemoton, proposed by Gánti. Since the chemoton is a system consisting of a large but fixed number of interacting molecular species, it can effectively be implemented in a process algebra-based language such as the BlenX programming language. The stochastic model behaves comparably to previous continuous deterministic models of the chemoton. Additionally to the well-known chemoton, we also implemented an extended version with two competing template cycles. The new insight from our study is that the coupling of reactions in the chemoton ensures that these templates coexist providing an alternative solution to Eigen's paradox. Our technical innovation involves the introduction of a two-state switch to control cell growth and division, thus providing an example for hybrid methods in BlenX. Further developments to the BlenX language are suggested in the Appendix.

  12. Two different template replicators coexisting in the same protocell: stochastic simulation of an extended chemoton model.

    Directory of Open Access Journals (Sweden)

    István Zachar

    Full Text Available The simulation of complex biochemical systems, consisting of intertwined subsystems, is a challenging task in computational biology. The complex biochemical organization of the cell is effectively modeled by the minimal cell model called chemoton, proposed by Gánti. Since the chemoton is a system consisting of a large but fixed number of interacting molecular species, it can effectively be implemented in a process algebra-based language such as the BlenX programming language. The stochastic model behaves comparably to previous continuous deterministic models of the chemoton. Additionally to the well-known chemoton, we also implemented an extended version with two competing template cycles. The new insight from our study is that the coupling of reactions in the chemoton ensures that these templates coexist providing an alternative solution to Eigen's paradox. Our technical innovation involves the introduction of a two-state switch to control cell growth and division, thus providing an example for hybrid methods in BlenX. Further developments to the BlenX language are suggested in the Appendix.

  13. Participatory development of incentives to coexist with jaguars and pumas.

    Science.gov (United States)

    Amit, Ronit; Jacobson, Susan K

    2018-01-22

    Reducing costs and increasing benefits for rural communities coexisting with large carnivores is necessary for conservation of jaguar (Panthera onca) and puma (Puma concolor). To design acceptable incentives, stakeholders must be involved in the process. We conducted an innovative, structured, group communication process based on a Delphi technique as a template for identifying potential incentives. Community workshops with 133 members of 7 communities and surveys with 25 multidisciplinary experts from government, nongovernmental organizations, and academia provided iterative data to design a plan of incentives through 4 rounds of discussion. The final product integrated 862 ideas into 6 types of incentives: organization of communities, mechanisms for improved dialogue, citizen technical assistance, green labeling for community products, payment for the ecosystem service of biodiversity, and an assessment of financial alternatives. We used quantitative and qualitative techniques to indicate support for decisions about the design of incentives, which reduced researcher subjectivity. The diverse incentives developed and the cooperation from multiple stakeholders resulted in an incentive plan that integrated issues of governance, equity, and social norms. © 2018 Society for Conservation Biology.

  14. Probabilistic Coexistence and Throughput of Cognitive Dual-Polarized Networks

    Directory of Open Access Journals (Sweden)

    J.-M. Dricot

    2010-01-01

    Full Text Available Diversity techniques for cognitive radio networks are important since they enable the primary and secondary terminals to efficiently share the spectral resources in the same location simultaneously. In this paper, we investigate a simple, yet powerful, diversity scheme by exploiting the polarimetric dimension. More precisely, we evaluate a scenario where the cognitive terminals use cross-polarized communications with respect to the primary users. Our approach is network-centric, that is, the performance of the proposed dual-polarized system is investigated in terms of link throughput in the primary and the secondary networks. In order to carry out this analysis, we impose a probabilistic coexistence constraint derived from an information-theoretic approach, that is, we enforce a guaranteed capacity for a primary terminal for a high fraction of time. Improvements brought about by the use of our scheme are demonstrated analytically and through simulations. In particular, the main simulation parameters are extracted from a measurement campaign dedicated to the characterization of indoor-to-indoor and outdoor-to-indoor polarization behaviors. Our results suggest that the polarimetric dimension represents a remarkable opportunity, yet easily implementable, in the context of cognitive radio networks.

  15. Nuclear shapes: from earliest ideas to multiple shape coexisting structures

    International Nuclear Information System (INIS)

    Heyde, K; Wood, J L

    2016-01-01

    The concept of the atomic nucleus being characterized by an intrinsic property such as shape came as a result of high precision hyperfine studies in the field of atomic physics, which indicated a non-spherical nuclear charge distribution. Herein, we describe the various steps taken through ingenious experimentation and bold theoretical suggestions that mapped the way for later work in the early 50s by Aage Bohr, Ben Mottelson and James Rainwater. We lay out a long and winding road that marked, in the period of 50s to 70s, the way shell-model and collective-model concepts were reconciled. A rapid increase in both accelerator and detection methods (70s towards the early 2000s) opened new vistas into nuclear shapes, and their coexistence, in various regions of the nuclear mass table. Next, we outline a possible unified view of nuclear shapes: emphasizing decisive steps taken as well as questions remaining, next to the theoretical efforts that could result in an emerging understanding of nuclear shapes, building on the nucleus considered as a strongly interacting system of nucleons as the microscopic starting point. (invited comment)

  16. Coexistence of potentiation and fatigue in skeletal muscle

    Directory of Open Access Journals (Sweden)

    D.E. Rassier

    2000-05-01

    Full Text Available Twitch potentiation and fatigue in skeletal muscle are two conditions in which force production is affected by the stimulation history. Twitch potentiation is the increase in the twitch active force observed after a tetanic contraction or during and following low-frequency stimulation. There is evidence that the mechanism responsible for potentiation is phosphorylation of the regulatory light chains of myosin, a Ca2+-dependent process. Fatigue is the force decrease observed after a period of repeated muscle stimulation. Fatigue has also been associated with a Ca2+-related mechanism: decreased peak Ca2+ concentration in the myoplasm is observed during fatigue. This decrease is probably due to an inhibition of Ca2+ release from the sarcoplasmic reticulum. Although potentiation and fatigue have opposing effects on force production in skeletal muscle, these two presumed mechanisms can coexist. When peak myoplasmic Ca2+ concentration is depressed, but myosin light chains are relatively phosphorylated, the force response can be attenuated, not different, or enhanced, relative to previous values. In circumstances where there is interaction between potentiation and fatigue, care must be taken in interpreting the contractile responses.

  17. Moving vortex matter with coexisting vortices and anti-vortices

    International Nuclear Information System (INIS)

    Carneiro, Gilson

    2009-01-01

    Moving vortex matter, driven by transport currents independent of time, in which vortices and anti-vortices coexist is investigated theoretically in thin superconducting films with nanostructured defects. A simple London model is proposed for the vortex dynamics in films with periodic arrays of nanomagnets or cylindrical holes (antidots). Common to these films is that vortex anti-vortex pairs may be created in the vicinity of the defects by relatively small transport currents, because it adds to the current generated by the defects - the nanomagnets screening current, or the antidots backflow current - and may exceed locally the critical value for vortex anti-vortex pair creation. The model assumes that vortex matter dynamics is governed by Langevin equations, modified to account for creation and annihilation of vortex anti-vortex pairs. For pair creation, it is assumed that whenever the total current at some location exceeds a critical value, equal to that needed to separate a vortex from an anti-vortex by a vortex core diameter, a pair is created instantaneously around this location. Pair annihilation occurs by vortex anti-vortex collisions. The model is applied to films at zero external magnetic field and low temperatures. It is found that several moving vortex matter steady-states with equal numbers of vortices and anti-vortices are possible.

  18. Dementia and serious coexisting medical conditions: a double whammy.

    Science.gov (United States)

    Maslow, Katie

    2004-09-01

    Research-based information about the prevalence of other serious medical conditions in people with dementia has become available only recently, and the true prevalence is not known, primarily because many people with dementia do not have a diagnosis. The existing information is sufficient, however, to show that these other conditions are common in people with dementia. It is also clear that coexisting medical conditions increase the use and cost of health care services for people with dementia, and conversely, dementia increases the use and cost of health care services for people with other serious medical conditions. Nurses and other healthcare professionals should expect to see these relationships in their elderly patients. They should know how to recognize possible dementia and assess, or obtain an assessment of, the patient's cognitive status. They should expect the worsening of cognitive and related symptoms in acutely ill people with dementia and try to eliminate factors that cause this worsening, to the extent possible, while assuring the family that the symptoms are likely to improve once the acute phase of illness or treatment is over. Families, nurses, and other health care professionals are challenged by the complex issues involved in caring for a person with both dementia and other serious medical conditions. Greater attention to these issues by informed and thoughtful clinicians will improve outcomes for the people and their family and professional caregivers.

  19. Coexistence Mechanism for Colocated HDR/LDR WPANs Air Interfaces

    Directory of Open Access Journals (Sweden)

    Prasad Ramjee

    2010-01-01

    Full Text Available This paper addresses the issues of interference management among Low Data Rate (LDR and High Data Rate (HDR WPAN air interfaces that are located in close-proximity (up to 10 cm and eventually on the same multimode device. After showing the noticeable performance degradation in terms of Bit Error Rate (BER and goodput due to the out-of-band interference of an HDR air interface over an LDR air interface, the paper presents a novel coexistence mechanism, named Alternating Wireless Activity (AWA, which is shown to greatly improve the performance in terms of goodput of the most interference vulnerable air interface (i.e., the LDR air interface. The main difference of the proposed mechanism with respect to other collaborative mechanisms based on time-scheduling is that it synchronizes the transmission of the LDR and HDR WPANs at the superframe level instead of packet level. Advantages and limitations of this choice are presented in the paper. Furthermore the functionalities of the AWA mechanism are positioned in a common protocol layer over the Medium Access Control (MAC sublayers of the HDR and LDR devices and it can be used with any standard whose MAC is based on a superframe structure.

  20. China and the global uranium market: prospects for peaceful coexistence.

    Science.gov (United States)

    Massot, Pascale; Chen, Zhan-Ming

    2013-01-01

    China's recent reemergence has resulted in a significant increase in the global demand of commodities and is already having major impacts on the dynamics of global commodity markets. In the case of the global uranium market, we stand at the very beginning of a period of change. However, interesting trends are already emerging. Whereas China has had many policy reversals, and some difficulties in taking control of its procurement strategy in other commodity markets, it is seemingly more successful in managing its uranium procurement strategy. Why? The argument presented here is that a mixture of domestic and international level variables has allowed China more room for maneuver in fulfilling its uranium procurement strategy. On the domestic level, a centralized industry, and, on the international level, a geographically dispersed and uncoordinated market have allowed China to forge ahead with an ambitious civilian nuclear power plan and triple its total uranium imports, all within the span of a few years. Many challenges remain, not the least that of negative public opinion, which has surged since the Fukushima disaster in 2011. Nevertheless, should uranium demand continue to grow, this paper will consider the potential for continued peaceful coexistence among uranium market participants worldwide.

  1. Shape coexistence and bubble structure in Iodine isotopes

    International Nuclear Information System (INIS)

    Naz, Tabassum; Karim, Afaque; Ahmad, Shakeb

    2017-01-01

    The evolution of the shape from the spherical to the axially deformed shapes of Iodine isotopes (Z=53, N=70-80) have been investigated in the framework of self-consistent Relativistic Hartree- Bogoliubov (RHB) calculations. A nonlinear meson-nucleon coupling model represented by the NL3* parametrization of the relativistic mean-field (RMF) theory has also been used. The bulk and the microscopic properties of these nuclei have been studied. The constraint calculation has been done to obtain potential energy surface (PES). The PES curves clearly shows the shape coexistence behaviour in these isotopes. We have also obtained the neutron, proton and total density of iodine isotopes. We observe the depletion in central density which indicates the bubble structure in iodine isotopes. For which, we have calculated Depletion Fraction (D.F) which clearly states that nuclei posses bubble structure in their intrinsic states. Overall good agreement is found within the different models used and between the calculated and experimental results wherever available. (author)

  2. Model-based monitoring of rotors with multiple coexisting faults

    International Nuclear Information System (INIS)

    Rossner, Markus

    2015-01-01

    Monitoring systems are applied to many rotors, but only few monitoring systems can separate coexisting errors and identify their quantity. This research project solves this problem using a combination of signal-based and model-based monitoring. The signal-based part performs a pre-selection of possible errors; these errors are further separated with model-based methods. This approach is demonstrated for the errors unbalance, bow, stator-fixed misalignment, rotor-fixed misalignment and roundness errors. For the model-based part, unambiguous error definitions and models are set up. The Ritz approach reduces the model order and therefore speeds up the diagnosis. Identification algorithms are developed for the different rotor faults. Hereto, reliable damage indicators and proper sub steps of the diagnosis have to be defined. For several monitoring problems, measuring both deflection and bearing force is very useful. The monitoring system is verified by experiments on an academic rotor test rig. The interpretation of the measurements requires much knowledge concerning the dynamics of the rotor. Due to the model-based approach, the system can separate errors with similar signal patterns and identify bow and roundness error online at operation speed. [de

  3. Primary lung cancer coexisting with active pulmonary tuberculosis.

    Science.gov (United States)

    Varol, Y; Varol, U; Unlu, M; Kayaalp, I; Ayranci, A; Dereli, M S; Guclu, S Z

    2014-09-01

    Lung cancer and pulmonary tuberculosis (TB) comorbidity is a clinical problem that presents a challenge for the diagnosis and treatment of both diseases. To clarify the clinical and survival characteristics of cases with both lung cancer and active pulmonary TB. From 2008 to 2013, 3350 TB patients admitted to the TB Department of the Chest Diseases Hospital of Izmir, Turkey, were evaluated. In 38 (1.1%) male patients, lung cancer and TB were found to coexist. Almost all of the patients were diagnosed at Stage III (n = 14, 36.8%) or IV (n = 17, 44.7%) lung cancer, whereas four (10.6%) had Stage II and three (7.9%) had Stage I disease. Squamous cell lung cancer was the predominant histology (n = 23, 60.7%). The median overall survival among patients was 13.4 months (95%CI 8.09-18.8). One-year survival rates for patients with Stages I, II, III and IV were respectively 100%, 75%, 57% and 40%. The present study demonstrates that lung cancer combined with active pulmonary TB most frequently presents as squamous cell carcinoma, with a male predominance. The overall survival of lung cancer patients did not change even with concomitant active TB.

  4. CT diagnosis of primary lung cancer coexisting with pulmonary tuberculosis

    International Nuclear Information System (INIS)

    Kim, Sun Joo; Kim, Young Sook; Oh, Jae Hee; Kim, Eun Kyoung; Kim, Young Chul

    1992-01-01

    When bronchogenic carcinoma is coexisting with pulmonary tuberculosis, it is difficult to differentiate bronchogenic carcinoma from pulmonary tuberculosis radiographically. Thus, the object of this study is to define differential diagnosis of bronchogenic carcinoma by computed tomography. We analyzed CT scans of 27 patients with radiologic findings of pulmonary tuberculosis and mass of which twelve cases were pulmonary tuberculosis and fifteen cases were primary lung cancer. The location of parenchymal infiltration and the mass was the same in 60%(9/15) of the primary lung cancer in cases and 83%(10/12) of the pulmonary tuberculosis cases. The common location of the mass was the both upper lobes in 92%(11/12) of the pulmonary tuberculosis cases and 53%(8/15) of the primary lung cancer cases. The common locations of the mediastinal lymphadenopathy were 4R, 2R of the pulmonary tuberculosis cases and 4R, 10R of the primary lung cancer cases. In the feature of post enhanced lymph nodes, homogenous increased density was more frequent in primary lung cancer. Measurements of the maximum thickness part of the cavity wall was not a reliable indication of malignancy

  5. Co-existence of Distinct Prion Types Enables Conformational Evolution of Human PrPSc by Competitive Selection*

    Science.gov (United States)

    Haldiman, Tracy; Kim, Chae; Cohen, Yvonne; Chen, Wei; Blevins, Janis; Qing, Liuting; Cohen, Mark L.; Langeveld, Jan; Telling, Glenn C.; Kong, Qingzhong; Safar, Jiri G.

    2013-01-01

    The unique phenotypic characteristics of mammalian prions are thought to be encoded in the conformation of pathogenic prion proteins (PrPSc). The molecular mechanism responsible for the adaptation, mutation, and evolution of prions observed in cloned cells and upon crossing the species barrier remains unsolved. Using biophysical techniques and conformation-dependent immunoassays in tandem, we isolated two distinct populations of PrPSc particles with different conformational stabilities and aggregate sizes, which frequently co-exist in the most common human prion disease, sporadic Creutzfeldt-Jakob disease. The protein misfolding cyclic amplification replicates each of the PrPSc particle types independently and leads to the competitive selection of those with lower initial conformational stability. In serial propagation with a nonglycosylated mutant PrPC substrate, the dominant PrPSc conformers are subject to further evolution by natural selection of the subpopulation with the highest replication rate due to its lowest stability. Cumulatively, the data show that sporadic Creutzfeldt-Jakob disease PrPSc is not a single conformational entity but a dynamic collection of two distinct populations of particles. This implies the co-existence of different prions, whose adaptation and evolution are governed by the selection of progressively less stable, faster replicating PrPSc conformers. PMID:23974118

  6. Evolutionary responses of native plant species to invasive plants : a review

    OpenAIRE

    Oduor, Ayub M. O.

    2013-01-01

    Strong competition from invasive plant species often leads to declines in abundances and may,in certain cases, cause localized extinctions of native plant species. Nevertheless, studies have shown that certain populations of native plant species can co-exist with invasive plant species, suggesting the possibility of adaptive evolutionary responses of those populations to the invasive plants. Empirical inference of evolutionary responses of the native plant species to invasive plants has invol...

  7. A Study on Coexistence Capability Evaluations of the Enhanced Channel Hopping Mechanism in WBANs

    Directory of Open Access Journals (Sweden)

    Zhongcheng Wei

    2017-01-01

    Full Text Available As an important coexistence technology, channel hopping can reduce the interference among Wireless Body Area Networks (WBANs. However, it simultaneously brings some issues, such as energy waste, long latency and communication interruptions, etc. In this paper, we propose an enhanced channel hopping mechanism that allows multiple WBANs coexisted in the same channel. In order to evaluate the coexistence performance, some critical metrics are designed to reflect the possibility of channel conflict. Furthermore, by taking the queuing and non-queuing behaviors into consideration, we present a set of analysis approaches to evaluate the coexistence capability. On the one hand, we present both service-dependent and service-independent analysis models to estimate the number of coexisting WBANs. On the other hand, based on the uniform distribution assumption and the additive property of Possion-stream, we put forward two approximate methods to compute the number of occupied channels. Extensive simulation results demonstrate that our estimation approaches can provide an effective solution for coexistence capability estimation. Moreover, the enhanced channel hopping mechanism can significantly improve the coexistence capability and support a larger arrival rate of WBANs.

  8. Coexistence of Malaria and Thalassemia in Malaria Endemic Areas of Thailand

    Science.gov (United States)

    Kuesap, Jiraporn; Chaijaroenkul, W.; Rungsihirunrat, K.; Pongjantharasatien, K.; Na-Bangchang, Kesara

    2015-01-01

    Hemoglobinopathy and malaria are commonly found worldwide particularly in malaria endemic areas. Thalassemia, the alteration of globin chain synthesis, has been reported to confer resistance against malaria. The prevalence of thalassemia was investigated in 101 malaria patients with Plasmodium falciparum and Plasmodium vivax along the Thai-Myanmar border to examine protective effect of thalassemia against severe malaria. Hemoglobin typing was performed using low pressure liquid chromatography (LPLC) and α-thalassemia was confirmed by multiplex PCR. Five types of thalassemia were observed in malaria patients. The 2 major types of thalassemia were Hb E (18.8%) and α-thalassemia-2 (11.9%). There was no association between thalassemia hemoglobinopathy and malaria parasitemia, an indicator of malaria disease severity. Thalassemia had no significant association with P. vivax infection, but the parasitemia in patients with coexistence of P. vivax and thalassemia was about 2-3 times lower than those with coexistence of P. falciparum and thalassemia and malaria without thalassemia. Furthermore, the parasitemia of P. vivax in patients with coexistence of Hb E showed lower value than coexistence with other types of thalassemia and malaria without coexistence. Parasitemia, hemoglobin, and hematocrit values in patients with coexistence of thalassemia other than Hb E were significantly lower than those without coexistence of thalassemia. Furthermore, parasitemia with coexistence of Hb E were 2 times lower than those with coexistence of thalassemia other than Hb E. In conclusion, the results may, at least in part, support the protective effect of thalassemia on the development of hyperparasitemia and severe anemia in malaria patients. PMID:26174819

  9. Phase coexistence in ferroelectric solid solutions: Formation of monoclinic phase with enhanced piezoelectricity

    Directory of Open Access Journals (Sweden)

    Xiaoyan Lu

    2016-10-01

    Full Text Available Phase morphology and corresponding piezoelectricity in ferroelectric solid solutions were studied by using a phenomenological theory with the consideration of phase coexistence. Results have shown that phases with similar energy potentials can coexist, thus induce interfacial stresses which lead to the formation of adaptive monoclinic phases. A new tetragonal-like monoclinic to rhombohedral-like monoclinic phase transition was predicted in a shear stress state. Enhanced piezoelectricity can be achieved by manipulating the stress state close to a critical stress field. Phase coexistence is universal in ferroelectric solid solutions and may provide a way to optimize ultra-fine structures and proper stress states to achieve ultrahigh piezoelectricity.

  10. Analysis of Coexisting GPON and NG-PON1 (10G-PON Systems

    Directory of Open Access Journals (Sweden)

    M. D. Mraković

    2011-06-01

    Full Text Available In this paper, the simulation model of coexisting GPON and NG-PON1 (10G-PON systems is presented, which has been developed for the analysis of feasibility and implementation issues of this coexistence. The aim was to analyze the impact of the most important parameters of the components that are needed for new network elements, on the performance of these coexistent networks. On the basis of the results obtained, the optimal parameters of the new system components were defined.

  11. Self-Coexistence among IEEE 802.22 Networks: Distributed Allocation of Power and Channel

    OpenAIRE

    Sayef Azad Sakin; Md. Abdur Razzaque; Mohammad Mehedi Hassan; Atif Alamri; Nguyen H. Tran; Giancarlo Fortino

    2017-01-01

    Ensuring self-coexistence among IEEE 802.22 networks is a challenging problem owing to opportunistic access of incumbent-free radio resources by users in co-located networks. In this study, we propose a fully-distributed non-cooperative approach to ensure self-coexistence in downlink channels of IEEE 802.22 networks. We formulate the self-coexistence problem as a mixed-integer non-linear optimization problem for maximizing the network data rate, which is an NP-hard one. This work explores a s...

  12. An ontological and enactive tool for education in management of coexistence

    OpenAIRE

    García de la Cerda, Osvaldo; Saavedra Ulloa, María Soledad

    2016-01-01

    Higher Education and the management of coexistence is an issue that is beginning to be included in the training of students and in teaching based on the demands made to teachers by the civil society and by the State in the last decade. The Ministry of Education of Chile formulates a National School Coexistence Policy that is being applied since 2002 in the country’s schools. It provides a conceptual and ethical framework to understand and act school coexistence from a rights and gender approa...

  13. Trade Mark Coexistence Agreements: What is all the (lack of) fuss about?

    DEFF Research Database (Denmark)

    Elsmore, Matthew J.

    2008-01-01

    time and space is allocated to trade mark coexistence agreements. Despite a shortage of authoritative rulings, it is not immediately clear why, especially as they may be having a profound impact on the use of product markers. Coexistence agreements commonly exist between parties with at least similar...... trade marks who decide to formally coexist, often in the wake of legal skirmishes. In the busy European market, where Community-wide protection is available, an up-front contract may be an attractive way to avoid trade mark conflict. When these contracts work, trade mark law is effectively pre...

  14. EFFECT OF FERRITE PHASE ON THE FORMATION AND COEXISTENCE OF 3CaO.3Al₂O₃.CaSO₄ AND 3CaO.SiO₂ MINERALS

    Directory of Open Access Journals (Sweden)

    Xiaolei Lu

    2017-12-01

    Full Text Available The effect of ferrite on the formation and coexistence of 3CaO.3Al₂O₃.CaSO₄ (C₄A₃$ and 3CaO.SiO₂ (C3S was investigated in this paper. The results indicate that 20 % content of ferrite phase with the composition of C₂A0.5F0.5 can facilitate the coexistence of C₄A₃$ and C₃S solid solutions at 1350 ° C. There are other trace elements that incorporate into clinker minerals and form solid solutions. In addition, the dark and polygonal C₄A₃$ solid solution is not dissolved in liquid phase at 1350 ° C. It can promote the burnability of the raw mixes and provide a favorable condition for the formation of C₃S. However, it has an adverse effect on the coexistence of two clinker minerals with the changing of ferrite compositions. This will provide the important basis for the preparation of the calcium sulphoaluminate cement clinker containing C₃S.

  15. Spatial patterns of encroaching shrub species under different ...

    African Journals Online (AJOL)

    ... in Middelburg (Eastern Cape, South Africa) coexist and partition space under different grazing regimes (viz. continuous rest, and continuous, summer and winter grazing). We used point-pattern analysis to assess the spatial ecology of these species. We also used an index of integration (mingling index), where low values ...

  16. Mineral nutrient economy in competing species of Sphagnum mosses

    Czech Academy of Sciences Publication Activity Database

    Hájek, Tomáš; Adamec, Lubomír

    2009-01-01

    Roč. 24, č. 2 (2009), s. 291-302 ISSN 0912-3814 R&D Projects: GA AV ČR KJB600050503 Institutional research plan: CEZ:AV0Z60050516 Keywords : exchange capacity * species coexistence * bog Subject RIV: EF - Botanics Impact factor: 1.485, year: 2009

  17. Comparison of nest shapes and densities of two sympatric species ...

    African Journals Online (AJOL)

    Two species of Cubitermes coexist in the grassy Loudetia Savanna of Bondoé, in the Central African Republic, namely C. sankurensis (Wasmann, 1911) and C. ugandensis (Fuller, 1923) Despite the obvious size difference between individuals their nests have the same general shape but there are significant, though small, ...

  18. Potential of genetically modified oilseed rape for biofuels in Austria: Land use patterns and coexistence constraints could decrease domestic feedstock production

    Science.gov (United States)

    Moser, Dietmar; Eckerstorfer, Michael; Pascher, Kathrin; Essl, Franz; Zulka, Klaus Peter

    2013-01-01

    Like other EU Member States, Austria will meet the substitution target of the EU European Renewable Energy Directive for transportation almost exclusively by first generation biofuels, primarily biodiesel from oilseed rape (OSR). Genetically modified (GM) plants have been promoted as a new option for biofuel production as they promise higher yield or higher quality feedstock. We tested implications of GM OSR application for biodiesel production in Austria by means of high resolution spatially explicit simulation of 140 different coexistence scenarios within six main OSR cropping regions in Austria (2400 km2). We identified structural land use characteristics such as field size, land use diversity, land holding patterns and the proportion of the target crop as the predominant factors which influence overall production of OSR in a coexistence scenario. Assuming isolation distances of 800 m and non-GM-OSR proportions of at least 10% resulted in a loss of area for cultivation of OSR in all study areas ranging from −4.5% to more than −25%, depending on the percentage of GM farmers and on the region. We could show that particularly the current primary OSR cropping regions are largely unsuitable for coexistence and would suffer from a net loss of OSR area even at isolation distances of 400 or 800 m. Coexistence constraints associated with application of GM OSR are likely to offset possible GM gains by substantially reducing farmland for OSR cultivation, thus contradicting the political aim to increase domestic OSR area to meet the combined demands of food, feed and biofuel production. PMID:26109750

  19. Positive parity states in 153Ho and the question of shape coexistence

    International Nuclear Information System (INIS)

    Chakraborty, A.; Ray, Sudatta; Ray, I.; Pradhan, M.K.; Raut, R.; Goswami, A.; Banerjee, P.; Mukherjee, A.; Bhattacharya, S.; Saha Sarkar, M.; Dey, Gautam; Krishichayan; Kshetri, Ritesh; Ganguly, S.; Ray Basu, M.; Ganguly, G.; Ghugre, S.S.; Sinha, A.K.; Basu, S.K.; Sarkar, S.

    2008-01-01

    In the present work the existing level scheme have been extended from the experimental data and studied specifically the positive parity states in 153 Ho theoretically to understand the issue of shape coexistence in this nucleus

  20. Co-existence of malaria and urinary tract infection among children ...

    African Journals Online (AJOL)

    Co-existence of malaria and urinary tract infection among children under five: ... was the predominant cause of the UTI and the isolates were highly resistant ... Keywords: Malaria, UTI, antibiotic sensitivity pattern, parasitaemia, bacteriuria, fever ...

  1. Co-existing institutional logics and agency among top-level public servants

    DEFF Research Database (Denmark)

    Bjerregaard, Toke

    2011-01-01

    to address parts of this void. This study examines the agency exerted by top-level public servants through their everyday strategy and policy work in face of co-existing logics of public administration. The findings illustrate how their action strategies span from more passive strategies of coping...... with coexisting logics of administration to more skilled agency of combining logics aimed at enhancing their opportunity and action space. The study suggests that the interplay between co-existing institutional logics, action strategies and the practical skills of top-level public servants provides the basis...... for both coping and more proactive strategies in pluralistic public administrations. Findings illustrate the role of public servants' practical sense of realizable opportunities that inform such strategies of handling co-existing institutional logics. Implications for institutional studies of organizations...

  2. Theoretical study on phase coexistence in ferroelectric solid solutions near the tricritical point

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Xiaoyan, E-mail: luxy@hit.edu.cn, E-mail: dzk@psu.edu; Li, Hui [Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education, School of Civil Engineering, Harbin Institute of Technology, Harbin 150001 (China); Zheng, Limei [Condensed Matter Science and Technology Institute, Harbin Institute of Technology, Harbin 150001 (China); Cao, Wenwu [Condensed Matter Science and Technology Institute, Harbin Institute of Technology, Harbin 150001 (China); Department of Mathematics and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

    2015-04-07

    Phase coexistence in ferroelectric solid solutions near the tricritical point has been theoretically analyzed by using the Landau-Devonshire theory. Results revealed that different phases having similar potential wells could coexist in a narrow composition range near the tricritical point in the classical Pb(Zr{sub 1−x}Ti{sub x})O{sub 3} system. The potential barrier between potential wells increases with the decrease of temperature. Coexisting phases or different domains of the same phase can produce adaptive strains to maintain atomic coherency at the interfaces or domain walls. Such compatibility strains have influence on the energy potential as well as the stability of relative phases, leading to the appearance of energetically unfavorable monoclinic phases. Those competing and coexisting phases also construct an easy phase transition path with small energy barrier in between, so that very small stimuli can produce large response in compositions near the morphotropic phase boundary, especially near the tricritical point.

  3. Theoretical study on phase coexistence in ferroelectric solid solutions near the tricritical point

    International Nuclear Information System (INIS)

    Lu, Xiaoyan; Li, Hui; Zheng, Limei; Cao, Wenwu

    2015-01-01

    Phase coexistence in ferroelectric solid solutions near the tricritical point has been theoretically analyzed by using the Landau-Devonshire theory. Results revealed that different phases having similar potential wells could coexist in a narrow composition range near the tricritical point in the classical Pb(Zr 1−x Ti x )O 3 system. The potential barrier between potential wells increases with the decrease of temperature. Coexisting phases or different domains of the same phase can produce adaptive strains to maintain atomic coherency at the interfaces or domain walls. Such compatibility strains have influence on the energy potential as well as the stability of relative phases, leading to the appearance of energetically unfavorable monoclinic phases. Those competing and coexisting phases also construct an easy phase transition path with small energy barrier in between, so that very small stimuli can produce large response in compositions near the morphotropic phase boundary, especially near the tricritical point

  4. Shape coexistence from lifetime and branching-ratio measurements in 68,70Ni

    Directory of Open Access Journals (Sweden)

    B.P. Crider

    2016-12-01

    Full Text Available Shape coexistence near closed-shell nuclei, whereby states associated with deformed shapes appear at relatively low excitation energy alongside spherical ones, is indicative of the rapid change in structure that can occur with the addition or removal of a few protons or neutrons. Near 68Ni (Z=28, N=40, the identification of shape coexistence hinges on hitherto undetermined transition rates to and from low-energy 0+ states. In 68,70Ni, new lifetimes and branching ratios have been measured. These data enable quantitative descriptions of the 0+ states through the deduced transition rates and serve as sensitive probes for characterizing their nuclear wave functions. The results are compared to, and consistent with, large-scale shell-model calculations which predict shape coexistence. With the firm identification of this phenomenon near 68Ni, shape coexistence is now observed in all currently accessible regions of the nuclear chart with closed proton shells and mid-shell neutrons.

  5. Osteomalacia and coxa vara. An unusual co-existence for femoral neck stress fracture

    Directory of Open Access Journals (Sweden)

    Kerim Sariyilmaz

    2015-01-01

    Conclusion: Joint and bone pain without any trauma should be investigated and bone metabolism disorders should be kept in mind. There might be co-existing factors related with stress fractures, and they must be treated simultaneously.

  6. Psychiatric emergencies (part II): psychiatric disorders coexisting with organic diseases.

    Science.gov (United States)

    Testa, A; Giannuzzi, R; Sollazzo, F; Petrongolo, L; Bernardini, L; Dain, S

    2013-02-01

    In this Part II psychiatric disorders coexisting with organic diseases are discussed. "Comorbidity phenomenon" defines the not univocal interrelation between medical illnesses and psychiatric disorders, each other negatively influencing morbidity and mortality. Most severe psychiatric disorders, such as schizophrenia, bipolar disorder and depression, show increased prevalence of cardiovascular disease, related to poverty, use of psychotropic medication, and higher rate of preventable risk factors such as smoking, addiction, poor diet and lack of exercise. Moreover, psychiatric and organic disorders can develop together in different conditions of toxic substance and prescription drug use or abuse, especially in the emergency setting population. Different combinations with mutual interaction of psychiatric disorders and substance use disorders are defined by the so called "dual diagnosis". The hypotheses that attempt to explain the psychiatric disorders and substance abuse relationship are examined: (1) common risk factors; (2) psychiatric disorders precipitated by substance use; (3) psychiatric disorders precipitating substance use (self-medication hypothesis); and (4) synergistic interaction. Diagnostic and therapeutic difficulty concerning the problem of dual diagnosis, and legal implications, are also discussed. Substance induced psychiatric and organic symptoms can occur both in the intoxication and withdrawal state. Since ancient history, humans selected indigene psychotropic plants for recreational, medicinal, doping or spiritual purpose. After the isolation of active principles or their chemical synthesis, higher blood concentrations reached predispose to substance use, abuse and dependence. Abuse substances have specific molecular targets and very different acute mechanisms of action, mainly involving dopaminergic and serotoninergic systems, but finally converging on the brain's reward pathways, increasing dopamine in nucleus accumbens. The most common

  7. Coexistence of graph-oriented and relational data file organisations in a data bank system

    International Nuclear Information System (INIS)

    Engel, K.D.

    1980-01-01

    It is shown that a coexistence of hierarchical and relational data bank structures in computer networks in a common data bank system is possible. This coexistence model, first established by NIJSSEN, regards the graph theory CODASYL approach and CODD's relational model as graph-oriented, or rather table-oriented, data file organisation as presented to the user of a common logical structure of the data bank. (WB) [de

  8. Search for shape coexistence in odd - Z rare earth proton emitters

    International Nuclear Information System (INIS)

    Aggarwal, Mamta

    2015-01-01

    Nuclear shapes are very sensitive to the structural effects and can change with isospin and from one nucleus to its neighbour and in some cases configurations corresponding to different shapes may coexist at similar energies which may arise from intruder excitations. Search for such interesting phenomena of shape coexistence and rapidly changing shapes in the less explored region of rare earth odd Z nuclei from Z = 51 to 75 are the focus of present work

  9. Coexistence of incommensurate magnetism and superconductivity in the two-dimensional Hubbard model

    Energy Technology Data Exchange (ETDEWEB)

    Yamase, Hiroyuki [Max Planck Institute for Solid State Research, Stuttgart (Germany); National Institute for Materials Science, Tsukuba (Japan); Eberlein, Andreas [Max Planck Institute for Solid State Research, Stuttgart (Germany); Department of Physics, Harvard University, Cambridge (United States); Metzner, Walter [Max Planck Institute for Solid State Research, Stuttgart (Germany)

    2016-07-01

    We analyze the competition of magnetism and superconductivity in the two-dimensional Hubbard model with a moderate interaction strength, including the possibility of incommensurate spiral magnetic order. Using an unbiased renormalization group approach, we compute magnetic and superconducting order parameters in the ground state. In addition to previously established regions of Neel order coexisting with d-wave superconductivity, the calculations reveal further coexistence regions where superconductivity is accompanied by incommensurate magnetic order.

  10. Coexisting Disadvantages in later Life: Demographic and Socio-Economic Inequalities

    OpenAIRE

    Heap, Josephine; Fors, Stefan; Lennartsson, Carin

    2016-01-01

    In this study, we aimed to identify which of certain demographic and socio-economic groups in the oldest part of the population that have an increased probability of experiencing simultaneous disadvantages in different life domains - here termed coexisting disadvantages. To do so, we compared analyses of coexisting disadvantages, measured as two or more simultaneous disadvantages, with analyses of single disadvantages and specific combinations of disadvantages. Indicators of physical health p...

  11. SPATIAL DIMENSION OF EXTERNALITIES AND THE COASE THEOREM: IMPLICATIONS FOR CO-EXISTENCE OF TRANSGENIC CROPS

    OpenAIRE

    Beckmann, Volker; Wesseler, Justus

    2005-01-01

    "No form of agriculture should be excluded in the EU." Many observers see this recent statement by European agricultural commissioner Franz Fischler as a clear signal towards a nearby lifting of the quasi EU moratorium on transgenic crops (or GMs for short) launched in 1998 (European Commission 2002). One of the last obstacles towards lifting the moratorium, however, is the problem of coexistence. How can GM-crops and non-GM-crops coexist? Since the European Environmental Agency published its...

  12. Discontinuous bifurcation and coexistence of attractors in a piecewise linear map with a gap

    International Nuclear Information System (INIS)

    Qu Shixian; Lu Yongzhi; Zhang Lin; He Daren

    2008-01-01

    Coexistence of attractors with striking characteristics is observed in this work, where a stable period-5 attractor coexists successively with chaotic band-11, period-6, chaotic band-12 and band-6 attractors. They are induced by different mechanisms due to the interaction between the discontinuity and the non-invertibility. A characteristic boundary collision bifurcation, is observed. The critical conditions are obtained both analytically and numerically. (general)

  13. A combined RT-PCR and dot-blot hybridization method reveals the coexistence of SJNNV and RGNNV betanodavirus genotypes in wild meagre (Argyrosomus regius).

    Science.gov (United States)

    Lopez-Jimena, B; Cherif, N; Garcia-Rosado, E; Infante, C; Cano, I; Castro, D; Hammami, S; Borrego, J J; Alonso, M C

    2010-10-01

    To detect the possible coexistence of striped jack nervous necrosis virus (SJNNV) and red-spotted grouper nervous necrosis virus (RGNNV) genotypes in a single fish, a methodology based on the combination of PCR amplification and blot hybridization has been developed and applied in this study. The degenerate primers designed for the PCR procedure target the T4 region within the capsid gene, resulting in the amplification of both genotypes. The subsequent hybridization of these amplification products with two different specific digoxigenin-labelled probes resulted in the identification of both genotypes separately. The application of the RT-PCR protocol to analyse blood samples from asymptomatic wild meagre (Argyrosomus regius) specimens has shown a 46.87% of viral nervous necrosis virus carriers. The combination of RT-PCR and blot hybridization increases the detection rate up to 90.62%, and, in addition, it has shown the coexistence of both genotypes in 18 out of the 32 specimens analysed (56.25%). This study reports the coexistence of betanodaviruses belonging to two different genotypes (SJNNV and RGNNV) in wild fish specimens. This is the first report demonstrating the presence of SJNNV and RGNNV genotypes in the same specimen. This study also demonstrates a carrier state in this fish species for the first time. © 2010 The Authors. Journal compilation © 2010 The Society for Applied Microbiology.

  14. Peaceful Co-existence in The Light of Objectives of Sharia’h

    Directory of Open Access Journals (Sweden)

    Shayuthy Abdul Manas

    2016-06-01

    Full Text Available The study focuses on clarifying the concept of peaceful coexistence, and its principles in the perspective of the “Maqasid Al-Shariah, (objectives of Islamic “Shariah” because, the most important purposes of “Maqasid AlShariah” are protection of soul, family, dignity and money. And also the establishment of security and peaceful life through the peaceful coexistence by following the basic foundations which are considered as important pillars of peaceful co-existence, these are nature, justice, freedom, and equality under the multiplicity of religions, different races and colors. Therefore, according to the interdependence between the objectives of “Shariah” and co-existence which is considered an important pillar of the social system, and the development of communities,the study focuses on highlighting some of the important problems that hinder the achievement of peaceful coexistence between Muslims and non-Muslims in the “Sri Lanka” due to the lack of knowledge about the reality of “Maqasid Al-Shariah” and its relationship to peaceful co-existence.

  15. Coexistence of Wormian Bones With Metopism, and Vice Versa, in Adult Skulls.

    Science.gov (United States)

    Cirpan, Sibel; Aksu, Funda; Mas, Nuket; Magden, Abdurrahman Orhan

    2016-03-01

    The aim of the study is to investigate coexistence of Wormian bones with metopism, and vice versa, in adult skulls. A total of 160 dry adult human skulls of unknown sex and ages were randomly selected from the Gross Anatomy Laboratory of Medical School of Dokuz Eylul University. The skulls were examined for presence of metopism, Wormian bones (WB), and coexistence of WBs with metopism and vice versa. Topographic distribution of the WBs was macroscopically evaluated within the skulls including metopism. The photographs were being taken with Canon 400B (55 mm objective). The frequency of metopism and WBs in 160 skulls is 7.50% (12/160) and 59.3% (95/160), respectively, P coexistence of WBs with metopism was found as 11 of 12 skulls (91.66%), whereas the incidence of coexistence of metopism with WBs was found as 11 of 95 skulls (11.58%), P coexistence of WBs with metopism (11/12, 91.66%) and coexistence of metopism with WBs (11/95, 11.58%). The factors leading to metopism may also lead to WBs, whereas that the factors leading to WBs may not lead to metopism.

  16. Intransitive competition is widespread in plant communities and maintains their species richness.

    Science.gov (United States)

    Soliveres, Santiago; Maestre, Fernando T; Ulrich, Werner; Manning, Peter; Boch, Steffen; Bowker, Matthew A; Prati, Daniel; Delgado-Baquerizo, Manuel; Quero, José L; Schöning, Ingo; Gallardo, Antonio; Weisser, Wolfgang; Müller, Jörg; Socher, Stephanie A; García-Gómez, Miguel; Ochoa, Victoria; Schulze, Ernst-Detlef; Fischer, Markus; Allan, Eric

    2015-08-01

    Intransitive competition networks, those in which there is no single best competitor, may ensure species coexistence. However, their frequency and importance in maintaining diversity in real-world ecosystems remain unclear. We used two large data sets from drylands and agricultural grasslands to assess: (1) the generality of intransitive competition, (2) intransitivity-richness relationships and (3) effects of two major drivers of biodiversity loss (aridity and land-use intensification) on intransitivity and species richness. Intransitive competition occurred in > 65% of sites and was associated with higher species richness. Intransitivity increased with aridity, partly buffering its negative effects on diversity, but was decreased by intensive land use, enhancing its negative effects on diversity. These contrasting responses likely arise because intransitivity is promoted by temporal heterogeneity, which is enhanced by aridity but may decline with land-use intensity. We show that intransitivity is widespread in nature and increases diversity, but it can be lost with environmental homogenisation. © 2015 John Wiley & Sons Ltd/CNRS.

  17. A distributed scheme to manage the dynamic coexistence of IEEE 802.15.4-based health-monitoring WBANs.

    Science.gov (United States)

    Deylami, Mohammad N; Jovanov, Emil

    2014-01-01

    The overlap of transmission ranges between wireless networks as a result of mobility is referred to as dynamic coexistence. The interference caused by coexistence may significantly affect the performance of wireless body area networks (WBANs) where reliability is particularly critical for health monitoring applications. In this paper, we analytically study the effects of dynamic coexistence on the operation of IEEE 802.15.4-based health monitoring WBANs. The current IEEE 802.15.4 standard lacks mechanisms for effectively managing the coexistence of mobile WBANs. Considering the specific characteristics and requirements of health monitoring WBANs, we propose the dynamic coexistence management (DCM) mechanism to make IEEE 802.15.4-based WBANs able to detect and mitigate the harmful effects of coexistence. We assess the effectiveness of this scheme using extensive OPNET simulations. Our results indicate that DCM improves the successful transmission rates of dynamically coexisting WBANs by 20%-25% for typical medical monitoring applications.

  18. A Generalist Protist Predator Enables Coexistence in Multitrophic Predator-Prey Systems Containing a Phage and the Bacterial Predator Bdellovibrio

    Directory of Open Access Journals (Sweden)

    Julia Johnke

    2017-10-01

    Full Text Available Complex ecosystems harbor multiple predators and prey species whose direct and indirect interactions are under study. In particular, the combined effects of predator diversity and resource preference on prey removal are not known. To understand the effect of interspecies interactions, combinations of micro-predators—i.e., protists (generalists, predatory bacteria (semi-specialists, and phages (specialists—and bacterial prey were tracked over a 72-h period in miniature membrane bioreactors. While specialist predators alone drove their preferred prey to extinction, the inclusion of a generalist resulted in uniform losses among prey species. Most importantly, presence of a generalist predator enabled coexistence of all predators and prey. As the generalist predator also negatively affected the other predators, we suggest that resource partitioning between predators and the constant availability of resources for bacterial growth due to protist predation stabilizes the system and keeps its diversity high. The appearance of resistant prey strains and subsequent evolution of specialist predators unable to infect the ancestral prey implies that multitrophic communities are able to persist and stabilize themselves. Interestingly, the appearance of BALOs and phages unable to infect their prey was only observed for the BALO or phage in the absence of additional predators or prey species indicating that competition between predators might influence coevolutionary dynamics.

  19. Location of an electric source facility and local area promotion

    International Nuclear Information System (INIS)

    Shimohirao, Isao

    1999-01-01

    Here were described on energy demand and supply, energy policy and local area promotion policy for basic problems important on location of electric source facilities. At present, co-existence business between electricity business and electric source location area is lacking in its activity. It seems to be necessary to enforce some systems to intend to promote it earnestly, and to effort to promote industry promotions such as introduction of some national projects, induction of electricity cost reduction for a means of business invitation, and so forth. And it is necessary to promote them under cooperations with electricity businesses, governments, universities and communities for the industrial promotion and fixation of the youth at local areas. In order to realize such necessities, further larger efforts are expected for national and local governments. (G.K.)

  20. Substoichiometrically different mitotypes coexist in mitochondrial genomes of Brassica napus L.

    Directory of Open Access Journals (Sweden)

    Jianmei Chen

    Full Text Available Cytoplasmic male sterility (CMS has been identified in numerous plant species. Brassica napus CMS plants, such as Polima (pol, MI, and Shaan 2A, have been identified independently by different researchers with different materials in conventional breeding processes. How this kind of CMS emerges is unclear. Here, we report the mitochondrial genome sequence of the prevalent mitotype in the most widely used pol-CMS line, which has a length of 223,412 bp and encodes 34 proteins, 3 ribosomal RNAs, and 18 tRNAs, including two near identical copies of trnH. Of these 55 genes, 48 were found to be identical to their equivalents in the "nap" cytoplasm. The nap mitotype carries only one copy of trnH, and the sequences of five of the six remaining genes are highly similar to their equivalents in the pol mitotype. Forty-four open reading frames (ORFs with unknown function were detected, including two unique to the pol mitotype (orf122 and orf132. At least five rearrangement events are required to account for the structural differences between the pol and nap sequences. The CMS-related orf224 neighboring region (∼5 kb rearranged twice. PCR profiling based on mitotype-specific primer pairs showed that both mitotypes are present in B. napus cultivars. Quantitative PCR showed that the pol cytoplasm consists mainly of the pol mitotype, and the nap mitotype is the main genome of nap cytoplasm. Large variation in the copy number ratio of mitotypes was found, even among cultivars sharing the same cytoplasm. The coexistence of mitochondrial mitotypes and substoichiometric shifting can explain the emergence of CMS in B. napus.

  1. Co-feeding transmission facilitates strain coexistence in Borrelia burgdorferi, the Lyme disease agent

    Directory of Open Access Journals (Sweden)

    S.L. States

    2017-06-01

    Full Text Available Coexistence of multiple tick-borne pathogens or strains is common in natural hosts and can be facilitated by resource partitioning of the host species, within-host localization, or by different transmission pathways. Most vector-borne pathogens are transmitted horizontally via systemic host infection, but transmission may occur in the absence of systemic infection between two vectors feeding in close proximity, enabling pathogens to minimize competition and escape the host immune response. In a laboratory study, we demonstrated that co-feeding transmission can occur for a rapidly-cleared strain of Borrelia burgdorferi, the Lyme disease agent, between two stages of the tick vector Ixodes scapularis while feeding on their dominant host, Peromyscus leucopus. In contrast, infections rapidly became systemic for the persistently infecting strain. In a field study, we assessed opportunities for co-feeding transmission by measuring co-occurrence of two tick stages on ears of small mammals over two years at multiple sites. Finally, in a modeling study, we assessed the importance of co-feeding on R0, the basic reproductive number. The model indicated that co-feeding increases the fitness of rapidly-cleared strains in regions with synchronous immature tick feeding. Our results are consistent with increased diversity of B. burgdorferi in areas of higher synchrony in immature feeding – such as the midwestern United States. A higher relative proportion of rapidly-cleared strains, which are less human pathogenic, would also explain lower Lyme disease incidence in this region. Finally, if co-feeding transmission also occurs on refractory hosts, it may facilitate the emergence and persistence of new pathogens with a more limited host range.

  2. Wind turbines and bats: towards a peaceful coexistence

    International Nuclear Information System (INIS)

    Heitz, P.

    2013-01-01

    The most important hazard for a bat is the collision with a rotating blade. The risk of collision depends on the wrong positioning of a wind turbine in the hunting area of a local population of bats and on the complex behaviour of bats. All the 34 species of bats living in France are protected species. Recommendations issued by the ministry of ecology include to perform preliminary impact studies on bat population before the installation of a wind turbine farm, to perform impact studies during wind turbine operations and to take measures to have the least impact as possible. The number of wind farms being on the rise, the knowledge of the behaviour of bats is getting more accurate through the use of dedicated instruments. (A.C.)

  3. A Two-Species Cooperative Lotka-Volterra System of Degenerate Parabolic Equations

    OpenAIRE

    Sun, Jiebao; Zhang, Dazhi; Wu, Boying

    2011-01-01

    We consider a cooperating two-species Lotka-Volterra model of degenerate parabolic equations. We are interested in the coexistence of the species in a bounded domain. We establish the existence of global generalized solutions of the initial boundary value problem by means of parabolic regularization and also consider the existence of the nontrivial time-periodic solution for this system.

  4. Coexistence of Aedes aegypti and Aedes albopictus (Diptera: Culicidae) in Peninsular Florida Two Decades After Competitive Displacements.

    Science.gov (United States)

    Lounibos, L Philip; Bargielowski, Irka; Carrasquilla, María Cristina; Nishimura, Naoya

    2016-11-01

    The spread of Aedes albopictus (Skuse) eastward in the mid-1980s from its initial establishment in Houston, TX, was associated with rapid declines and local disappearances of Aedes aegypti (L.) in Gulf Coast states and Florida where annual larval surveillance during the early 1990s described temporal and spatial patterns of competitive displacements in cemeteries and tire shops. Approximately 20 yr later in 2013-2014, we re-visited former collection sites and sampled aquatic immatures of these two species from tire shops in 10 cities on State Route 441 and from 9 cemeteries from Lakeland to Miami in southwest Florida. In the recent samples Ae. aegypti was recovered from three central Florida cities where it had not been detected in 1994, but its northern limit on Rte. 441, Apopka, did not change. Other evidence, such as trends at a few cemeteries, suggested a moderate resurgence of this species since 1994. Cage experiments that exposed female progeny of Ae. aegypti from recent Florida collection sites to interspecific mating by Ae. albopictus males showed that females from coexistence sites had evolved resistance to cross-mating, but Ae. aegypti from sites with no Ae. albopictus were relatively susceptible to satyrization. Habitat classifications of collection sites were reduced by principal component (PC) analysis to four variables that accounted for > 99% of variances; PCs with strong positive loadings for tree cover and ground vegetation were associated with collection sites yielding only Ae. albopictus Within the coexistence range of the two species, the numbers of Ae. aegypti among total Aedes collected were strongly correlated in stepwise logistic regression models with two habitat-derived PCs, distance from the coast, and annual rainfall and mean maximum temperatures at the nearest weather station. Subtle increases in the range of Ae. aegypti since its previous displacements are interpreted in the context of the evolution of resistance to mating

  5. Health promotion.

    Science.gov (United States)

    Miyake, S; Lucas-Miyake, M

    1989-01-01

    This article will describe a marketing model for the development of a role for occupational therapy in the industrial market. Health promotion activities are used as a means to diversify existing revenue bases by establishing new referral sources in industry. The technique of need satisfaction -selling or marketing one's services to a customer based on needs expressed by the customer - is reviewed, and implementation of this approach is described from two settings, one in psychiatry and the other in rehabilitation.

  6. COEXISTENCE OF CARCINOMAS OF THYROID WITH MULTINODULAR GOITRES OF THYROID – A TWO-YEAR STUDY

    Directory of Open Access Journals (Sweden)

    Kiran Kumar Epari

    2016-08-01

    Full Text Available BACKGROUND Multinodular goitre or nodular hyperplasia or adenomatoid goitre is the most common thyroid disease, which occurs due to deficient iodine intake. Initial hyperthyroid states, followed by follicular atrophy and secondary changes like haemorrhage, calcification and cystic degeneration occurs in most of the cases. Longstanding cases of nodular goitre can be associated with carcinomas, usually follicular carcinomas, and rarely papillary carcinomas.[1] This study was done to know the incidence of coexisting malignancies, follicular and papillary carcinomas of thyroid, in longstanding nodular goitres of thyroid. METHODS All the cases of nodular goitres examined in the last two years were studied, including the thyroidectomy specimens and FNAC slides whichever was done. Extensive grossing of the thyroidectomy specimens was done to detect the possibility of malignancy in longstanding cases of nodular goitre of thyroid. Review of FNAC slides was done in cases where cytodiagnosis of coexisting malignancy was missed and detected in histopathological examination. RESULTS In the present study, conducted over a two-year period, out of 50 cases of thyroidectomy specimens of multinodular goitres studied, six cases were diagnosed to be having coexisting malignancy of thyroid, of which four were follicular carcinomas of thyroid and two were papillary carcinomas of thyroid. FNAC diagnosis of coexisting malignancy was initially missed in FNAC in two cases, i.e. one case each of follicular carcinoma and papillary carcinoma. These FNAC slides were reviewed and the foci of malignancies detected. CONCLUSION There is a possibility of malignancy of thyroid coexisting with longstanding multinodular goitre of thyroid, which should be kept in mind, while performing the needle biopsy and thorough examination of FNAC slides is needed to avoid missing the possible detection of the coexisting malignant lesion. Thyroidectomy specimens should be extensively grossed to

  7. Canadian Schizophrenia Guidelines: Schizophrenia and Other Psychotic Disorders with Coexisting Substance Use Disorders.

    Science.gov (United States)

    Crockford, David; Addington, Donald

    2017-09-01

    Persons with schizophrenia and other psychotic disorders frequently have coexisting substance use disorders that require modifications to treatment approaches for best outcomes. The objectives of this review were to identify evidence-based practices best practices that improve outcomes for individuals with schizophrenia and substance used disorders. We reviewed guidelines that were published in the last 5 years and that included systematic reviews or meta-analyses. Most of our recommendations came from 2 publications from the National Institute for Health and Care Excellence (NICE): the 2011 guidance titled Coexisting Severe Mental Illness (Psychosis) and Substance Misuse: Assessment and Management in Healthcare Settings and the 2014 guidance titled Psychosis and Schizophrenia in Adults: Prevention and Management. We placed these recommendations into the Canadian context to create this guideline. Evidence supports the inclusion of individuals with coexisting substance use disorders in first-episode psychosis programs. The programs should integrate psychosis and substance use treatments, emphasizing ongoing monitoring of both substance use and patterns and symptoms. The best outcomes are achieved with combined use of antipsychotic medications and addiction-based psychosocial interventions. However, limited evidence is available to recommend using one antipsychotic medication over another or one psychosocial intervention over another for persons with schizophrenia and other psychotic disorders with coexisting substance use disorders. Treating persons who have schizophrenia and other psychotic disorders with coexisting substance use disorders can present clinical challenges, but modifications in practice can help engage and retain people in treatment, where significant improvements over time can be expected.

  8. Space Use Variation in Co-Occurring Sister Species: Response to Environmental Variation or Competition?

    Science.gov (United States)

    Dufour, Claire M. S.; Meynard, Christine; Watson, Johan; Rioux, Camille; Benhamou, Simon; Perez, Julie; du Plessis, Jurie J.; Avenant, Nico; Pillay, Neville; Ganem, Guila

    2015-01-01

    Coexistence often involves niche differentiation either as the result of environmental divergence, or in response to competition. Disentangling the causes of such divergence requires that environmental variation across space is taken into account, which is rarely done in empirical studies. We address the role of environmental variation versus competition in coexistence between two rodent species: Rhabdomys bechuanae (bechuanae) and Rhabdomys dilectus dilectus (dilectus) comparing their habitat preference and home range (HR) size in areas with similar climates, where their distributions abut (allopatry) or overlap (sympatry). Using Outlying Mean Index analyses, we test whether habitat characteristics of the species deviate significantly from a random sample of available habitats. In allopatry, results suggest habitat selection: dilectus preferring grasslands with little bare soil while bechuanae occurring in open shrublands. In sympatry, shrubland type habitats dominate and differences are less marked, yet dilectus selects habitats with more cover than bechuanae. Interestingly, bechuanae shows larger HRs than dilectus, and both species display larger HRs in sympatry. Further, HR overlaps between species are lower than expected. We discuss our results in light of data on the phylogeography of the genus and propose that evolution in allopatry resulted in adaptation leading to different habitat preferences, even at their distribution margins, a divergence expected to facilitate coexistence. However, since sympatry occurs in sites where environmental characteristics do not allow complete species separation, competition may explain reduced inter-species overlap and character displacement in HR size. This study reveals that both environmental variation and competition may shape species coexistence. PMID:25693176

  9. Promoting industrialisation

    International Nuclear Information System (INIS)

    Hayfield, F.

    1986-04-01

    When the first nuclear power programme is decided upon, automatically the country has to initiate in parallel a programme to modify or add to its current industrial structure and resources. The extent of this new industrialisation depends upon many factors which both, the Government and the Industries have to consider. The Government has a vital role which includes the setting up of the background against which the industrial promotion should take place and in many cases may have also to play an active role all along this programme. Equally, the existing industries have an important role so as to achieve the most efficient participation in the nuclear programme. Invariably the industrial promotional programme will incur a certain degree of transfer of technology, the extent depending on the policies adopted. For this technology transfer to take place efficiently, both the donor and the receiver have to recognise each other's legitimate ambitions and fears. The transfer of technology is a process having a high human content and both donor and receiver have to take this into account. This can be further complicated when there is a difference in culture between them. Technology transfer is carried out within a contractual and organisational framework which will identify the donor (licensor) and the receiver (licensee). This framework may take various forms from a simple cooperative agreement, through a joint-venture organisation right to a standard contract between two separate entities. Each arrangement has its advantages and drawbacks and requires investment of different degrees. One of the keys to a successful industrial promotion is having it carried out in a timely fashion which will be parallel with the nuclear power programme. Experience in some countries has shown the problems when the industrialisation is out of phase with the programme whilst in other cases this industrialisation was at a level and scale unjustified. (author)

  10. Effect of litter, leaf cover and cover of basal internodes of the dominant species Molinia caerulea on seedling recruitment and established vegetation

    Science.gov (United States)

    Janeček, Štěpán; Lepš, Jan

    2005-09-01

    The effects of litter removal, leaf cover of established plants and cover of basal internodes of a dominant species Molinia caerulea on seedling germination and the dynamics of established plants were studied in a field experiment in an oligotrophic wet meadow. Although the negative influence of litter on total seedling number and seedling species composition was non-significant, litter significantly affected the dynamics of the established vegetation and caused inhibition of total leaf cover development. The effects of total leaf cover of established plants on seedling establishment changed during the vegetation season. Whereas the effect of total leaf cover was positive at the start and in the middle of the vegetation season, at the end the total leaf cover negatively affected seedling establishment. Both total leaf cover and cover of basal internodes affected seedling composition. Effects of these two variables were statistically separable suggesting that they are based on different mechanisms. The response of seedling establishment to these factors was species specific and, consequently, our data support the hypothesis that that biotically generated spatial heterogeneity can promote species co-existence through the differentiation of species regeneration niches.

  11. The liquid–liquid coexistence curves of {benzonitrile + n-pentadecane} and {benzonitrile + n-heptadecane} in the critical region

    International Nuclear Information System (INIS)

    Chen, Zhiyun; Bai, Yongliang; Yin, Tianxiang; An, Xueqin; Shen, Weiguo

    2012-01-01

    Highlights: ► Coexistence curves of (benzonitrile + n-pentadecane) and (benzonitrile + n-heptadecane) were measured. ► The values of the critical exponent β are consistent with that predicted by the 3D-Ising model. ► The coexistence curves are well described by the critical crossover model. ► The asymmetry of the diameters of the coexistence curves were discussed by the complete scaling theory. - Abstract: Liquid + liquid coexistence curves for the binary solutions of {benzonitrile + n-pentadecane} and {benzonitrile + n-heptadecane} have been measured in the critical region. The critical exponent β and the critical amplitudes have been deduced and the former is consistent with the theoretic prediction. It was found that the coexistence curves may be well described by the crossover model proposed by Gutkowski et al. The asymmetries of the diameters of the coexistence curves were also discussed in the frame of the complete scaling theory.

  12. Dams and river dolphins: Can they co-exist?

    International Nuclear Information System (INIS)

    Reeves, R.R.; Leatherwood, S.

    1994-01-01

    Dam construction is one of many ways that humans have modified river-dolphin habitats. It is suggested that physiographic and hydrologic complexity plays an important role in making rivers suitable for dolphins. If this hypothesis is true, then it can be assumed that dams and other artificial obstructions degrade dolphin habitat insofar as they reduce such complexity. This paper identifies some of the impacts that dams, barrages, and dikes might have on dolphins. Research is needed at project sites, both before and after construction, to document impacts. Specially designed ''swimways'' may allow upstream and downstream passage by dolphins and thus mitigate at least one of the adverse effects of dam projects, namely population fragmentation, but such measures aimed at benefiting single species are no substitute for protecting ecosystems. 30 refs

  13. Semiinvasive Aspergillosis Case Coexisting to Metastatic Renal Cell Cancer

    Directory of Open Access Journals (Sweden)

    Hatice Kilic

    2013-10-01

    Full Text Available Chronic necrotizing pulmonary aspergillosis (CNPA is defined as an cavity or mass lesion in the lung due to invasion of lung tissue by a fungus of the Aspergillosis species. It was described also as semiinvasive aspergillosis. Semiinvasive pulmonary aspergillosis is generally seen in patients with primer immunocompromised and it can be fatal in the event of late diagnose. We present 60 years old patient who had had renal cell cancer admitted to hospital with metastatic nodules in his chest X-ray and Thorax computed tomography. We have seen yellow colour of bronchial secretion in his bronchoscopy. Multipl mantar hyphae by A. Fumigatus was detected in his bronchial lavage cytology. Itrakonazol was administred to this patient. We review to this cases due to a semiinvasive aspergillosis was detected randomly when this case who had not both symptomatic and clinical sign by Aspergillosis is investigated.

  14. Working Hours, Promotion and the Gender Gap in the Workplace

    DEFF Research Database (Denmark)

    Kato, Takao; Owan, Hideo; Ogawa, Hiromasa

    thereof. The firm's decision to provide training also depends on its private information about the worker's OJT ability, which affects his/her future productivity if and when the worker gets promoted. Upon completion of training, the firm then promotes the worker. The model illuminates under what......This paper presents a novel model of promotion within the firm which sheds new light on the interplay between working hours and the odds of subsequent promotion. The model's key feature is the coexistence of two different sources of asymmetric information: (i) the worker's cost of long working....../her on the job. Long working hours signal the worker's commitment to the firm, which determines the surplus produced when the worker is promoted. Thus, the firm provides the worker with managerial training only after observing the employee's hours worked, a signal of his/her commitment to the firm or lack...

  15. COEXISTENCE OF PRIVATE FIRMS AND OPEN SOURCE FIRMS UNDER SPILLOVERS AND CONSUMER BIAS

    Directory of Open Access Journals (Sweden)

    Murat YILMAZ

    2017-12-01

    Full Text Available Open source technologies have been an important divergence from the private produc- tion, and some markets have accommodated both open source firms and private firms. We explore the conditions under which such a coexistence of both type of firms can be seen. Through a simple and tractable game theoretical model, with spillovers on the open source production and positive consumer bias for the privately produced good, we analyze the conditions for which, in the equilibrium, a private firm and an open source firm share the market. We find that for large enough consumer bias, the two types cannot coexist, however when the consumer bias is relatively low and the spillover effect is not too strong, then we get a coexistence result.

  16. [Effect of cigarette smoking on coexistence of cadmium and zinc in retained wisdom teeth].

    Science.gov (United States)

    Malara, Piotr; Kwapuliński, Jerzy; Drugacz, Jan; Malara, Beata

    2005-01-01

    The change in coexistence pattern of elements (antagonism-synergism) in conditions of excessive level of toxic element is observed in many biological samples. The aim of this study was to establish the cadmium and zinc content in hard tissues of retained wisdom teeth of smokers and non-smokers and to find out if active exposure to cigarette smoke has an influence on coexistence of both metals in these tissues. Material consisted of 127 retained wisdom teeth (65 from smokers and 62 from non-smokers). Cadmium and zinc contents were determined by means of atomic absorption spectrometry. We found out that retained wisdom tooth from smokers exhibited higher cadmium and zinc contents compared to non-smokers' teeth. Moreover, coexistence pattern of cadmium and zinc in teeth depends on exposure to heavy metals and exhibits strong synergism in smokers.

  17. Non-local coexistence of multiple spiral waves with independent frequencies

    International Nuclear Information System (INIS)

    Zhan Meng; Luo Jinming

    2009-01-01

    The interactions of several spiral waves with different independent rotation frequencies are studied in a model of two-dimensional complex Ginzburg-Laudau equation. We find a general coexistence phenomenon, non-local non-phase-locking-invasion coexistence, that is, the non-slowest spiral wave can survive and not be killed by the fastest spiral wave as it is insulated from the fastest one with the sacrifice of the slowest one, which stays in the spatial position between the fastest spiral and the non-slowest one. Both the parameter non-monotonicity and the non-phase-locking invasion between the fastest and the slowest spiral waves play key roles in this phenomenon. Importantly, the results could give a general idea for extensively observed coexistence of spiral waves in various inhomogeneous circumstances.

  18. The coexistence of natural and supernatural explanations within and across domains and development.

    Science.gov (United States)

    Busch, Justin T A; Watson-Jones, Rachel E; Legare, Cristine H

    2017-03-01

    People across highly diverse cultural contexts use both natural and supernatural explanations to explain questions of fundamental concern such as death, illness, and human origins. The present study examines the development of explanatory coexistence within and across domains of existential concern in individuals in Tanna, Vanuatu. We examined three age groups: 7- to 12-year-old children, 13- to 18-year-old adolescents, and 19- to 70-year-old adults (N = 72). Within the domain of death, biological and spontaneous explanations were most common across all ages. For illness, children showed the highest rates of explanatory coexistence, while adolescents and adults favoured biological explanations. Within the human origins domain, theistic explanations were most common across the age groups. Overall, these data show that coexistence reasoning in these domains is pervasive across cultures, yet at the same time it is deeply contextually specific, reflecting the nuanced differences in local ecologies and cultural beliefs. Statement of contribution What is already known on this subject? Individuals across highly diverse cultural contexts use both natural and supernatural explanations to understand the events that occur in their lives. Context and cultural input play a large role in determining when and how individuals incorporate natural and supernatural explanations. The development of explanatory coexistence has primarily studied explanations for isolated domains. What does this study add? We examined explanatory coexistence in a culture with recent conversion to Christianity and formal education. The current research examines how individuals reason within and across the domains of human origins, illness, and death. Developmental differences associated with explanatory coexistence are examined. © 2016 The British Psychological Society.

  19. A clinical study and meta-analysis of carotid stenosis with coexistent intracranial aneurysms.

    Science.gov (United States)

    Yang, Ximeng; Lu, Jun; Wang, Junjie; Wang, Lijun; Qi, Peng; Hu, Shen; Chen, Kunpeng; Wang, Daming

    2018-06-01

    Carotid stenosis (CS) and intracranial aneurysms (IAs) may concur in one person. We studied the prevalence of IAs in CS patients in our retrospectively collected database and systematically reviewed this issue. Five hundred and fifty-seven CS (≥50%) patients confirmed by DSA in our hospital from 2010-06 to 2015-06 were screened for coexistent IAs. After searching the related literatures from English and Chinese journal literature databases, a meta-analysis was performed to pool the prevalence of CS with coexistent IAs. Subgroup analyses were performed to explore the causes of heterogeneity among studies. IAs were detected in 98(17.0%) out of the 577 CS patients. 12 literatures and the present study including a total of 6965 CS patients and 446 cases with coexistent IAs. The pooled prevalence of CS with coexistent IAs was 6.3% (95%CI: 4.2-8.3%) in all the CS patients. The pooled RR for female to male CS patients to have coexistent IAs was 1.67 (95%CI: 1.34-2.08, P = 0.000). 3 studies and the present study were carried out in Asian countries with a pooled prevalence of 10.8% (95%CI: 5.3-16.3%); 6 studies in European countries with 3.0% (95%CI: 2.2-3.7%); and 3 studies in USA with 6.0% (95%CI: 2.2-9.7%). There was a statistically significant difference between the three subgroups (P IAs in CS patients seems higher in our clinical study and the meta-analysis than in the general population and previously reported. The eastern and the women CS patients have a higher risk for coexistent IAs. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Revisiting the two-layer hypothesis: coexistence of alternative functional rooting strategies in savannas.

    Science.gov (United States)

    Holdo, Ricardo M

    2013-01-01

    The two-layer hypothesis of tree-grass coexistence posits that trees and grasses differ in rooting depth, with grasses exploiting soil moisture in shallow layers while trees have exclusive access to deep water. The lack of clear differences in maximum rooting depth between these two functional groups, however, has caused this model to fall out of favor. The alternative model, the demographic bottleneck hypothesis, suggests that trees and grasses occupy overlapping rooting niches, and that stochastic events such as fires and droughts result in episodic tree mortality at various life stages, thus preventing trees from otherwise displacing grasses, at least in mesic savannas. Two potential problems with this view are: 1) we lack data on functional rooting profiles in trees and grasses, and these profiles are not necessarily reflected by differences in maximum or physical rooting depth, and 2) subtle, difficult-to-detect differences in rooting profiles between the two functional groups may be sufficient to result in coexistence in many situations. To tackle this question, I coupled a plant uptake model with a soil moisture dynamics model to explore the environmental conditions under which functional rooting profiles with equal rooting depth but different depth distributions (i.e., shapes) can coexist when competing for water. I show that, as long as rainfall inputs are stochastic, coexistence based on rooting differences is viable under a wide range of conditions, even when these differences are subtle. The results also indicate that coexistence mechanisms based on rooting niche differentiation are more viable under some climatic and edaphic conditions than others. This suggests that the two-layer model is both viable and stochastic in nature, and that a full understanding of tree-grass coexistence and dynamics may require incorporating fine-scale rooting differences between these functional groups and realistic stochastic climate drivers into future models.