WorldWideScience

Sample records for abundance promote coexistence

  1. The role of competition – colonization tradeoffs and spatial heterogeneity in promoting trematode coexistence

    Science.gov (United States)

    Mordecai, Erin A.; Jaramillo, Alejandra G.; Ashford, Jacob E.; Hechinger, Ryan F.; Lafferty, Kevin D.

    2016-01-01

    Competition – colonization tradeoffs occur in many systems, and theory predicts that they can strongly promote species coexistence. However, there is little empirical evidence that observed competition – colonization tradeoffs are strong enough to maintain diversity in natural systems. This is due in part to a mismatch between theoretical assumptions and biological reality in some systems. We tested whether a competition – colonization tradeoff explains how a diverse trematode guild coexists in California horn snail populations, a system that meets the requisite criteria for the tradeoff to promote coexistence. A field experiment showed that subordinate trematode species tended to have higher colonization rates than dominant species. This tradeoff promoted coexistence in parameterized models but did not fully explain trematode diversity and abundance, suggesting a role of additional diversity maintenance mechanisms. Spatial heterogeneity is an alternative way to promote coexistence if it isolates competing species. We used scale transition theory to expand the competition – colonization tradeoff model to include spatial variation. The parameterized model showed that spatial variation in trematode prevalence did not isolate most species sufficiently to explain the overall high diversity, but could benefit some rare species. Together, the results suggest that several mechanisms combine to maintain diversity, even when a competition – colonization tradeoff occurs.

  2. Phenological Differences Promote Coexistence in Sonoran Desert Winter Annuals

    Science.gov (United States)

    Kimball, S.; Angert, A.; Huxman, T.; Venable, L.

    2008-12-01

    Identifying trait differences is an important step toward understanding differential demographic responses to the same environmental fluctuations. In the Sonoran Desert, winter annual plants exhibit high demographic variability due to variation in precipitation, and patterns of demographic variability are related to species position along a tradeoff axis between relative growth rate (RGR) and water-use efficiency (WUE). Prior investigation revealed that species with high RGR and low WUE have greater inter-annual variability than species with low RGR and high WUE. In this study, we use long-term census data, climate records, and plot data to investigate timing of germination, reproduction, and senescence of several winter annual species in multiple years to test whether phenology relates to demographic variability and position along the tradeoff axis. We also use climate records to describe germination niches of the species and make predictions regarding future community composition. We hypothesized that seasonal phenology would differ such that demographically 'buffered' species (low RGR-high WUE) would germinate, flower, and senesce earlier in the season due to an ability to utilize small amounts of rain and photosynthesize at low temperatures. In contrast, we hypothesized that the demographically 'variable' species (high RGR-low WUE) would germinate later in the season, only after enough rain had fallen to break seed dormancy. Consistent with our hypothesis, buffered species did germinate and reproduce earlier in the season than variable species. Contrary to our hypothesis, buffered species also survived later into the season. Variable species germinated later, reproduced quickly, and senesced earlier in the season. These results show that phenology promotes coexistence by partitioning resource use. Germination niches and climate data suggest that buffered species may increase in abundance through time.

  3. Allee effects and species co-existence in an environment where resource abundance varies.

    Science.gov (United States)

    M'Gonigle, Leithen K; Greenspoon, Philip B

    2014-11-21

    Explaining patterns of diversity has long been a central focus in ecology. One of the most challenging problems has been to understand how species occupying similar ecological niches can co-exist because, with limited resources, demographic stochasticity is expected to lead to the eventual extinction of all but one of them. The Allee effect has been widely studied for its impact on the extinction risk of rare species. Its potential role in promoting co-existence has received less attention. Here, we present a model in which two species compete for a single resource across a continuous landscape. We show that Allee effects can promote their co-existence when a simple condition is met: resources are distributed unevenly across space. Furthermore, the Allee effect can stabilize co-existence despite the reduction in population density and consequent increase in demographic stochasticity that it causes. The Allee effect might, therefore, be an important force maintaining diverse communities.

  4. 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

  5. Trait adaptation promotes species coexistence in diverse predator and prey communities.

    Science.gov (United States)

    Klauschies, Toni; Vasseur, David A; Gaedke, Ursula

    2016-06-01

    Species can adjust their traits in response to selection which may strongly influence species coexistence. Nevertheless, current theory mainly assumes distinct and time-invariant trait values. We examined the combined effects of the range and the speed of trait adaptation on species coexistence using an innovative multispecies predator-prey model. It allows for temporal trait changes of all predator and prey species and thus simultaneous coadaptation within and among trophic levels. We show that very small or slow trait adaptation did not facilitate coexistence because the stabilizing niche differences were not sufficient to offset the fitness differences. In contrast, sufficiently large and fast trait adaptation jointly promoted stable or neutrally stable species coexistence. Continuous trait adjustments in response to selection enabled a temporally variable convergence and divergence of species traits; that is, species became temporally more similar (neutral theory) or dissimilar (niche theory) depending on the selection pressure, resulting over time in a balance between niche differences stabilizing coexistence and fitness differences promoting competitive exclusion. Furthermore, coadaptation allowed prey and predator species to cluster into different functional groups. This equalized the fitness of similar species while maintaining sufficient niche differences among functionally different species delaying or preventing competitive exclusion. In contrast to previous studies, the emergent feedback between biomass and trait dynamics enabled supersaturated coexistence for a broad range of potential trait adaptation and parameters. We conclude that accounting for trait adaptation may explain stable and supersaturated species coexistence for a broad range of environmental conditions in natural systems when the absence of such adaptive changes would preclude it. Small trait changes, coincident with those that may occur within many natural populations, greatly enlarged

  6. Evaluating the ecological impacts of salvage logging: can natural and anthropogenic disturbances promote coexistence?

    Science.gov (United States)

    Royo, Alejandro A; Peterson, Chris J; Stanovick, John S; Carson, Walter P

    2016-06-01

    Salvage logging following windthrow is common throughout forests worldwide even though the practice is often considered inimical to forest recovery. Because salvaging removes trees, crushes seedlings, and compacts soils, many warn this practice may delay succession, suppress diversity, and alter composition. Here, over 8 yr following windthrow, we experimentally evaluate how salvaging affects tree succession across 11 gaps in Eastern deciduous forests of Pennsylvania, wherein each gap was divided into salvaged and control (unsalvaged) halves. Our gaps vary in size and windthrow severity, and we explicitly account for this variation as well as variation in soil disturbance (i.e., scarification) resulting from salvaging so that our results would be generalizable. Salvage logging had modest and ephemeral impacts on tree succession. Seedling richness and density declined similarly over time in both salvaged and unsalvaged areas as individuals grew into saplings. The primary impact of salvaging on succession occurred where salvaging scarified soils. Here, salvaging caused 41 to 82% declines in sapling abundance, richness, and diversity, but these differences largely disappeared within 5 yr. Additionally, we documented interactions between windthrow severity and scarification. Specifically, low-severity windthrow and scarification combined reinforced dominance by shade-tolerant and browse-tolerant species (Acer pensylvanicum, Fagus grandifolia). In contrast, high windthrow severity and scarification together reduced the density of a fast-growing pioneer tree (Prunus pensylvanica) and non-tree vegetation cover by 75% and 26%, respectively. This reduction enhanced the recruitment of two mid-successional tree species, Acer rubrum and Prunus serotina, by 2 and 3-fold, respectively. Thus, our findings demonstrate that salvaging creates novel microsites and mitigates competing vegetation, thereby enhancing establishment of important hardwoods and promoting tree species

  7. Plant-soil feedbacks promote negative frequency dependence in the coexistence of two aridland grasses.

    Science.gov (United States)

    Chung, Y Anny; Rudgers, Jennifer A

    2016-07-27

    Understanding the mechanisms of species coexistence is key to predicting patterns of species diversity. Historically, the ecological paradigm has been that species coexist by partitioning resources: as a species increases in abundance, self-limitation kicks in, because species-specific resources decline. However, determining coexistence mechanisms has been a particular puzzle for sedentary organisms with high overlap in their resource requirements, such as plants. Recent evidence suggests that plant-associated microbes could generate the stabilizing self-limitation (negative frequency dependence) that is required for species coexistence. Here, we test the key assumption that plant-microbe feedbacks cause such self-limitation. We used competition experiments and modelling to evaluate how two common groups of soil microbes (rhizospheric microbes and biological soil crusts) influenced the self-limitation of two competing desert grass species. Negative feedbacks between the dominant plant competitor and its rhizospheric microbes magnified self-limitation, whereas beneficial interactions between both plant species and biological soil crusts partly counteracted this stabilizing effect. Plant-microbe interactions have received relatively little attention as drivers of vegetation dynamics in dry land ecosystems. Our results suggest that microbial mechanisms can contribute to patterns of plant coexistence in arid grasslands.

  8. Ethnic Division in Cyprus and a Policy Initiative on Promoting Peaceful Coexistence: Toward an Agonistic Democracy for Citizenship Education

    Science.gov (United States)

    Zembylas, Michalinos

    2011-01-01

    This article uses as a point of departure for its analysis a recent educational policy initiative to promote peaceful coexistence in the context of ongoing ethnic division in Cyprus. It is argued that, although it seems as if the teaching of peaceful coexistence is a laudable initiative that can contribute toward unity and democratic…

  9. Coexistence of TERT promoter and BRAF mutations in cutaneous melanoma is associated with more clinicopathological features of aggressiveness.

    Science.gov (United States)

    Macerola, Elisabetta; Loggini, Barbara; Giannini, Riccardo; Garavello, Giulia; Giordano, Mirella; Proietti, Agnese; Niccoli, Cristina; Basolo, Fulvio; Fontanini, Gabriella

    2015-08-01

    The recently described telomerase reverse transcriptase (TERT) promoter mutations are recurrent in cutaneous melanoma. Several authors have described an association between these molecular alterations, some histological parameters, and patient survival. BRAF mutations are very frequent in melanoma, but their actual role in the evolution of the disease is still unclear. Here, we investigated the relationship of TERT promoter mutations and BRAF mutations with the most relevant clinicopathological parameters, individually and coexisting, in order to evaluate their role as independent prognostic markers and to determine the effect of their coexistence. A TERT promoter alteration was found in 20 of 53 cases (38 %), significantly associated with histological type, increasing tumor thickness and mitotic rate, more advanced pathologic tumor (pT) stage, and absence of regression. A BRAF mutation was found in 21 of 53 cases (40 %), significantly associated with tumor thickness and presence of metastases in the sentinel lymph node. Coexistence of a TERT promoter and BRAF mutation was detected in 11 of 53 cases (21 %). This was associated with increasing thickness, high mitotic rate, lymph node metastasis, presence of ulceration, and absence of regression. Coexistence of a mutation in the TERT promoter and in the BRAF gene correlated with more prognostically relevant factors than either mutation alone. Our data lead us to hypothesize that TERT promoter and BRAF mutations cooperate in cutaneous melanoma. Further studies in larger cohorts of patients are needed to investigate how this synergistic effect is involved in the evolution of the disease.

  10. 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)…

  11. Promoting Peaceful Coexistence in Conflict-Ridden Cyprus: Teachers' Difficulties and Emotions towards a New Policy Initiative

    Science.gov (United States)

    Zembylas, Michalinos; Charalambous, Constadina; Charalambous, Panayiota; Kendeou, Panayiota

    2011-01-01

    The present paper looks at teachers' perceptions of difficulties and emotions about a recent policy initiative in the Greek-Cypriot educational system to promote peaceful coexistence. This policy initiative by the government sparked strong emotional reactions. This paper provides an in-depth understanding of the intersection between tensions at…

  12. 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

  13. The evolution of coexistence: Reciprocal adaptation promotes the assembly of a simple community.

    Science.gov (United States)

    Bassar, Ronald D; Simon, Troy; Roberts, William; Travis, Joseph; Reznick, David N

    2017-02-01

    Species coexistence may result by chance when co-occurring species do not strongly interact or it may be an evolutionary outcome of strongly interacting species adapting to each other. Although patterns like character displacement indicate that coexistence has often been an evolutionary outcome, it is unclear how often the evolution of coexistence represents adaptation in only one species or reciprocal adaptation among all interacting species. Here, we demonstrate a strong role for evolution in the coexistence of guppies and killifish in Trinidadian streams. We experimentally recreated the temporal stages in the invasion and establishment of guppies into communities that previously contained only killifish. We combined demographic responses of guppies and killifish with a size-based integral projection model to calculate the fitness of the phenotypes of each species in each of the stages of community assembly. We show that guppies from locally adapted populations that are sympatric with killifish have higher fitness when paired with killifish than guppies from allopatric populations. This elevated fitness involves effects traceable to both guppy and killifish evolution. We discuss the implications of our results to the study of species coexistence and how it may be mediated through eco-evolutionary feedbacks. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

  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

    Russia’s annexation of Crimea and its role in the war in Ukraine is a thorny issue for the BRICS grouping, consisting of Brazil, Russia, India, China and South Africa. Crimea and Ukraine strains the internal cohesion of the BRICS principles not to use aggression to solve conflicts......, 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...... threat against sovereignty in the post-Soviet sphere, that left Moscow with little choice but to take action. In The BRICS and Coexistence: an Alternative Vision of World Order we have argued that the BRICS articulate an alternative framework for global governance which we called coexistence. We...

  15. Competitive spatially distributed population dynamics models: Does diversity in diffusion strategies promote coexistence?

    Science.gov (United States)

    Braverman, E; Kamrujjaman, Md; Korobenko, L

    2015-06-01

    We study the interaction between different types of dispersal, intrinsic growth rates and carrying capacities of two competing species in a heterogeneous environment: one of them is subject to a regular diffusion while the other moves in the direction of most per capita available resources. If spatially heterogeneous carrying capacities coincide, and intrinsic growth rates are proportional then competitive exclusion of a regularly diffusing population is inevitable. However, the situation may change if intrinsic growth rates for the two populations have different spatial forms. We also consider the case when carrying capacities are different. If the carrying capacity of a regularly diffusing population is higher than for the other species, the two populations may coexist; as the difference between the two carrying capacities grows, competitive exclusion of the species with a lower carrying capacity occurs.

  16. Examining the role of individual movement in promoting coexistence in a spatially explicit prisoner's dilemma.

    Science.gov (United States)

    Burgess, Andrew E F; Lorenzi, Tommaso; Schofield, Pietà G; Hubbard, Stephen F; Chaplain, Mark A J

    2017-02-27

    The emergence of cooperation is a major conundrum of evolutionary biology. To unravel this evolutionary riddle, several models have been developed within the theoretical framework of spatial game theory, focussing on the interactions between two general classes of player, "cooperators" and "defectors". Generally, explicit movement in the spatial domain is not considered in these models, with strategies moving via imitation or through colonisation of neighbouring sites. We present here a spatially explicit stochastic individual-based model in which pure cooperators and defectors undergo random motion via diffusion and also chemotaxis guided by the gradient of a semiochemical. Individual movement rules are derived from an underlying system of reaction-diffusion-taxis partial differential equations which describes the dynamics of the local number of individuals and the concentration of the semiochemical. Local interactions are governed by the payoff matrix of the classical prisoner's dilemma, and accumulated payoffs are translated into offspring. We investigate the cases of both synchronous and non-synchronous generations. Focussing on an ecological scenario where defectors are parasitic on cooperators, we find that random motion and semiochemical sensing bring about self-generated patterns in which resident cooperators and parasitic defectors can coexist in proportions that fluctuate about non-zero values. Remarkably, coexistence emerges as a genuine consequence of the natural tendency of cooperators to aggregate into clusters, without the need for them to find physical shelter or outrun the parasitic defectors. This provides further evidence that spatial clustering enhances the benefits of mutual cooperation and plays a crucial role in preserving cooperative behaviours.

  17. Floral resource availability from groundcover promotes bee abundance in coffee agroecosystems.

    Science.gov (United States)

    Fisher, Kaleigh; Gonthier, David J; Ennis, Katherine K; Perfecto, Ivette

    2017-09-01

    Patterns of bee abundance and diversity across different spatial scales have received thorough research consideration. However, the impact of short- and long-term temporal resource availability on biodiversity has been less explored. This is highly relevant in tropical agricultural systems for pollinators, as many foraging periods of pollinators extend beyond flowering of any single crop species. In this study, we sought to understand how bee communities in tropical agroecosystems changed between seasons, and if short- and long-term floral resource availability influenced their diversity and abundance. We used a threshold analysis approach in order to explore this relationship at two time scales. This study took place in a region dominated by coffee agroecosystems in Southern Mexico. This was an ideal system because the landscape offers a range of coffee management regimes that maintain heterogeneity in floral resource availability spatially and temporally. We found that the bee community varies significantly between seasons. There were higher abundances of native social, solitary and managed honey bees during the dry season when coffee flowers. Additionally, we found that floral resources from groundcover, but not trees, were associated with bee abundance. Further, the temporal scale of the availability of these resources is important, whereby short-term floral resource availability appears particularly important in maintaining high bee abundance at sites with lower seasonal complementarity. We argue that in addition to spatial resource heterogeneity, temporal resource heterogeneity is critical in explaining bee community patterns, and should thus be considered to promote pollinator conservation. © 2017 by the Ecological Society of America.

  18. PKCtheta and HIV-1 transcriptional regulator Tat co-exist at the LTR promoter in CD4+ T cells

    Directory of Open Access Journals (Sweden)

    Maria Rosa eLopez-Huertas

    2016-02-01

    Full Text Available PKCtheta is essential for the activation of CD4+ T cells. Upon TCR/CD28 stimulation, PKCtheta is phosphorylated and migrates to the immunological synapse, inducing the activation of cellular transcription factors such as NF-kB and kinases as ERK that are critical for HIV-1 replication. We previously demonstrated that PKCtheta is also necessary for HIV-1 replication but the precise mechanism is unknown. Efficient HIV-1 transcription and elongation is absolutely dependent on the synergy between NF-kB and the viral regulator Tat. Tat exerts its function by binding a RNA stem-loop structure proximal to the viral mRNA cap site termed TAR. Besides, due to its effect on cellular metabolic pathways, Tat causes profound changes in infected CD4+ T cells such as the activation of NF-kB and ERK. We hypothesized that the aberrant up-regulation of Tat-mediated activation of NF-kB and ERK occurred through PKCtheta signaling. In fact, Jurkat TetOff cells with stable and doxycycline-repressible expression of Tat (Jurkat-Tat expressed high levels of mRNA for PKCtheta. In these cells, PKCtheta located at the plasma membrane was phosphorylated at T538 residue in undivided cells, in the absence of stimulation. Treatment with doxycycline inhibited PKCtheta phosphorylation in Jurkat-Tat, suggesting that Tat expression was directly related to the activation of PKCtheta. Both NF-kB and Ras/Raf/MEK/ERK signaling pathway were significantly activated in Jurkat-Tat cells, and this correlated with high transactivation of HIV-1 LTR promoter. RNA interference for PKCtheta inhibited NF-kB and ERK activity, as well as LTR-mediated transactivation even in the presence of Tat. In addition to Tat-mediated activation of PKCtheta in the cytosol, we demonstrated by sequential ChIP that Tat and PKCtheta coexisted in the same complex bound at the HIV-1 LTR promoter, specifically at the region containing TAR loop. In conclusion, PKCtheta-Tat interaction seemed to be essential for HIV-1

  19. Photosynthetic phenological variation may promote coexistence among co-dominant tree species in a Madrean sky island mixed conifer forest.

    Science.gov (United States)

    Potts, D L; Minor, R L; Braun, Z; Barron-Gafford, G A

    2017-09-01

    Across much of western North America, forests are predicted to experience a transition from snow- to rain-dominated precipitation regimes due to anthropogenic climate warming. Madrean sky island mixed conifer forests receive a large portion of their precipitation from summertime convective storms and may serve as a lens into the future for snow-dominated forests after prolonged warming. To better understand the linkage between physiological traits, climate variation, and the structure and function of mixed conifer forests, we measured leaf photosynthetic (A) responses to controlled variation in internal CO2 concentration (Ci) to quantify interspecific phenological variation in A/Ci-derived ecophysiological traits among ponderosa pine (Pinus ponderosa Lawson and C. Lawson), southwestern white pine (Pinus strobiformis Engelm.) and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). Species had similar, positive responses in net photosynthesis under ambient conditions (Anet) to the onset of summertime monsoonal precipitation, but during the cooler portions of the year P. ponderosa was able to maintain greater Anet than P. menziesii and P. strobiformis. Moreover, P. ponderosa had greater Anet in response to ephemerally favorable springtime conditions than either P. menziesii or P. strobiformis. Monsoonal precipitation was associated with a sharp rise in the maximum rates of electron transport (Jmax) and carboxylation (VCmax) in P. menziesii in comparison with P. ponderosa and P. strobiformis. In contrast, species shared similar low values of Jmax and VCmax in response to cool winter temperatures. Patterns of relative stomatal limitation followed predictions based on species' elevational distributions, reinforcing the role of stomatal behavior in maintaining hydraulic conductivity and shaping bioclimatic limits. Phenological variation in ecophysiologial traits among co-occurring tree species in a Madrean mixed conifer forest may promote temporal resource partitioning

  20. Patterns of abundance and maturity among three species of parasitic nematodes (Pseudoterranova decipiens, Contracaecum osculatum, Anisakis simplex co-existing in Sable Island grey seals (Halichoerus grypus

    Directory of Open Access Journals (Sweden)

    G Mark Fowler

    2001-11-01

    Full Text Available The abundance and maturity of three species of anisakine nematode (Pseudoterranova decipiens, Contracaecum osculatum, Anisakis simplex that co-occurred in the stomachs of Sable Island grey seals were examined in relation to seal growth and seasonal considerations. Sealworm (P. decipiens, the predominant nematode in these seals, typically reached numbers of 400 to 2000 worms per stomach. C. osculatum and A. simplex were usually found in much smaller numbers of 40 to 100 and 20 to 60 worms, respectively, per stomach. All three species initially increased in abundance as the seals grew, but after most of a seals’ growth had been attained P. decipiens abundance continued to increase with age, A. simplex numbers either continued to increase or were simply maintained, while C. osculatum abundance declined. Numbers of both P. decipiens and A. simplex declined during winter breeding/pupping and summer moulting fasts or partial fasts, and rose during the regular feeding periods between the fasts. Conversely, numbers of C. osculatum rose during the breeding period, and also during the moulting period in younger seals. We believe this could be attributed to some degree of feeding on prey species in the immediate vicinity of Sable Island that were not preferred during focused feeding periods, and that the inclination to feed during fasting periods decreased as seals grew. An inverse relationship between worm abundance and worm maturity, attributable to the seasonal changes in rates of ingestion of immature worms, was more pronounced for C. osculatum than P. decipiens. C. osculatum was usually represented by much higher proportions of mature worms than P. decipiens. This could be entirely related to the longer periods of time dedicated to feeding than spent breeding or moulting, but higher mortality rates of immature C. osculatum or greater longevity of mature C. osculatum could also have occurred. A. simplex, generally associated with cetacean species

  1. 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.

  2. Pseudomonas aeruginosa Alginate Overproduction Promotes Coexistence with Staphylococcus aureus in a Model of Cystic Fibrosis Respiratory Infection.

    Science.gov (United States)

    Limoli, Dominique H; Whitfield, Gregory B; Kitao, Tomoe; Ivey, Melissa L; Davis, Michael R; Grahl, Nora; Hogan, Deborah A; Rahme, Laurence G; Howell, P Lynne; O'Toole, George A; Goldberg, Joanna B

    2017-03-21

    While complex intra- and interspecies microbial community dynamics are apparent during chronic infections and likely alter patient health outcomes, our understanding of these interactions is currently limited. For example, Pseudomonas aeruginosa and Staphylococcus aureus are often found to coinfect the lungs of patients with cystic fibrosis (CF), yet these organisms compete under laboratory conditions. Recent observations that coinfection correlates with decreased health outcomes necessitate we develop a greater understanding of these interbacterial interactions. In this study, we tested the hypothesis that P. aeruginosa and/or S. aureus adopts phenotypes that allow coexistence during infection. We compared competitive interactions of P. aeruginosa and S. aureus isolates from mono- or coinfected CF patients employing in vitro coculture models. P. aeruginosa isolates from monoinfected patients were more competitive toward S. aureus than P. aeruginosa isolates from coinfected patients. We also observed that the least competitive P. aeruginosa isolates possessed a mucoid phenotype. Mucoidy occurs upon constitutive activation of the sigma factor AlgT/U, which regulates synthesis of the polysaccharide alginate and dozens of other secreted factors, including some previously described to kill S. aureus Here, we show that production of alginate in mucoid strains is sufficient to inhibit anti-S. aureus activity independent of activation of the AlgT regulon. Alginate reduces production of siderophores, 2-heptyl-4-hydroxyquinolone-N-oxide (HQNO), and rhamnolipids-each required for efficient killing of S. aureus These studies demonstrate alginate overproduction may be an important factor driving P. aeruginosa coinfection with S. aureusIMPORTANCE Numerous deep-sequencing studies have revealed the microbial communities present during respiratory infections in cystic fibrosis (CF) patients are diverse, complex, and dynamic. We now face the challenge of determining

  3. Pseudomonas aeruginosa Alginate Overproduction Promotes Coexistence with Staphylococcus aureus in a Model of Cystic Fibrosis Respiratory Infection

    Science.gov (United States)

    Limoli, Dominique H.; Whitfield, Gregory B.; Kitao, Tomoe; Ivey, Melissa L.; Davis, Michael R.; Grahl, Nora; Hogan, Deborah A.; Rahme, Laurence G.; Howell, P. Lynne

    2017-01-01

    ABSTRACT While complex intra- and interspecies microbial community dynamics are apparent during chronic infections and likely alter patient health outcomes, our understanding of these interactions is currently limited. For example, Pseudomonas aeruginosa and Staphylococcus aureus are often found to coinfect the lungs of patients with cystic fibrosis (CF), yet these organisms compete under laboratory conditions. Recent observations that coinfection correlates with decreased health outcomes necessitate we develop a greater understanding of these interbacterial interactions. In this study, we tested the hypothesis that P. aeruginosa and/or S. aureus adopts phenotypes that allow coexistence during infection. We compared competitive interactions of P. aeruginosa and S. aureus isolates from mono- or coinfected CF patients employing in vitro coculture models. P. aeruginosa isolates from monoinfected patients were more competitive toward S. aureus than P. aeruginosa isolates from coinfected patients. We also observed that the least competitive P. aeruginosa isolates possessed a mucoid phenotype. Mucoidy occurs upon constitutive activation of the sigma factor AlgT/U, which regulates synthesis of the polysaccharide alginate and dozens of other secreted factors, including some previously described to kill S. aureus. Here, we show that production of alginate in mucoid strains is sufficient to inhibit anti-S. aureus activity independent of activation of the AlgT regulon. Alginate reduces production of siderophores, 2-heptyl-4-hydroxyquinolone-N-oxide (HQNO), and rhamnolipids—each required for efficient killing of S. aureus. These studies demonstrate alginate overproduction may be an important factor driving P. aeruginosa coinfection with S. aureus. PMID:28325763

  4. Forested landscapes promote richness and abundance of native bees (Hymenoptera: Apoidea: Anthophila) in Wisconsin apple orchards.

    Science.gov (United States)

    Watson, J C; Wolf, A T; Ascher, J S

    2011-06-01

    Wild bees provide vital pollination services for many native and agricultural plant species, yet the landscape conditions needed to support wild bee populations are not well understood or appreciated. We assessed the influence of landscape composition on bee abundance and species richness in apple (Malus spp.) orchards of northeastern Wisconsin during the spring flowering period. A diverse community of bee species occurs in these apple orchards, dominated by wild bees in the families Andrenidae and Halictidae and the honey bee, Apis mellifera L. Proportion of forest area in the surrounding landscape was a significant positive predictor of wild bee abundance in orchards, with strongest effects at a GIS (Geographic Information Systems) buffer distance of 1,000 m or greater. Forest area also was positively associated with species richness, showing strongest effects at a buffer distance of 2,000 m. Nonagricultural developed land (homes, lawns, etcetera) was significantly negatively associated with species richness at buffer distances >750 m and wild bee abundance in bowl traps at all distances. Other landscape variables statistically associated with species richness or abundance of wild bees included proportion area of pasture (positive) and proportion area of roads (negative). Forest area was not associated with honey bee abundance at any buffer distance. These results provide clear evidence that the landscape surrounding apple orchards, especially the proportion of forest area, affects richness and abundance of wild bees during the spring flowering period and should be a part of sustainable land management strategies in agro-ecosystems of northeastern Wisconsin and other apple growing regions.

  5. Aldosterone-mineralocorticoid receptor promotes urine prostasin through glomerular barrier injury and not tissue abundance

    DEFF Research Database (Denmark)

    Stolzenburg Oxlund, Christina; Kurt, B.; Schwarzensteiner, I.

    2015-01-01

    Objective: Low salt intake or infusion with the mineralocorticoid hormone aldosterone increases the abundance of proteolytically activated gamma ENaC in rat kidney. Prostasin is a serine proteinase GPI-anchored to the apical membrane of renal principal cells. It was hypothesized that the aldoster......Objective: Low salt intake or infusion with the mineralocorticoid hormone aldosterone increases the abundance of proteolytically activated gamma ENaC in rat kidney. Prostasin is a serine proteinase GPI-anchored to the apical membrane of renal principal cells. It was hypothesized...

  6. Czech Ambassador:Abundant Opportunities to Promote Czech-China Trade

    Institute of Scientific and Technical Information of China (English)

    Sun Yongjian

    2006-01-01

    @@ Q1:Would you give us your comments on China's job in 2005 in promoting the economic and trade relations with your country? A:For promoting the economic and trade relations between countries it is very important to meet counterparts, discuss potential problems and prospect of expanding cooperation.

  7. Lottery coexistence on rocky shores: weak niche differentiation or equal competitors engaged in neutral dynamics?

    Science.gov (United States)

    Shinen, Jennifer L; Navarrete, Sergio A

    2014-03-01

    Reconciling how niche and neutral processes may be important in species coexistence has revealed two important weaknesses in our collective understanding of species diversity: few empirical studies have determined whether species are truly coexisting, and fewer still have properly evaluated whether coexistence is achieved through niche differentiation or ecological equivalence. Here, we ask whether two common barnacles, Jehlius cirratus and Notochthamalus scabrosus, coexist locally and whether the slight but persistent differences in their distribution provide sufficient fitness trade-offs to overcome differences in competition. Both species recovered after experimental reduction; that is, they coexist, with no indication of hierarchical exclusion. No fitness inequalities affected species performance or interference effects on vital rates at any shore level, indicating no trade-offs in intra-interspecific effects across the ecological gradient. Additionally, no relationship was found between per capita population growth rates of either species with its own relative abundance; that is, neither species has a demographic advantage when rare. Instead, a lottery for space during settlement largely determines species' distributions, evidenced by the positive correlation across sites and tidal elevations between the relative abundances of adults and the recruits of the prior season. We conclude that Jehlius and Notochthamalus coexist neutrally, or nearly so, but discuss whether small, nonsignificant, and probably ephemeral fitness differences, which are inconsistent across the tidal gradient, could provide enough niche differentiation to promote coexistence.

  8. Integration of molecular biology tools for identifying promoters and genes abundantly expressed in flowers of Oncidium Gower Ramsey

    Directory of Open Access Journals (Sweden)

    Tung Shu-Yun

    2011-04-01

    Full Text Available Abstract Background Orchids comprise one of the largest families of flowering plants and generate commercially important flowers. However, model plants, such as Arabidopsis thaliana do not contain all plant genes, and agronomic and horticulturally important genera and species must be individually studied. Results Several molecular biology tools were used to isolate flower-specific gene promoters from Oncidium 'Gower Ramsey' (Onc. GR. A cDNA library of reproductive tissues was used to construct a microarray in order to compare gene expression in flowers and leaves. Five genes were highly expressed in flower tissues, and the subcellular locations of the corresponding proteins were identified using lip transient transformation with fluorescent protein-fusion constructs. BAC clones of the 5 genes, together with 7 previously published flower- and reproductive growth-specific genes in Onc. GR, were identified for cloning of their promoter regions. Interestingly, 3 of the 5 novel flower-abundant genes were putative trypsin inhibitor (TI genes (OnTI1, OnTI2 and OnTI3, which were tandemly duplicated in the same BAC clone. Their promoters were identified using transient GUS reporter gene transformation and stable A. thaliana transformation analyses. Conclusions By combining cDNA microarray, BAC library, and bombardment assay techniques, we successfully identified flower-directed orchid genes and promoters.

  9. Do natural container habitats impede invader dominance? Predator-mediated coexistence of invasive and native container-dwelling mosquitoes.

    Science.gov (United States)

    Kesavaraju, Banugopan; Damal, Kavitha; Juliano, Steven A

    2008-03-01

    Predator-mediated coexistence of competitors occurs when a species that is superior in competition is also more vulnerable to a shared predator compared to a poorer competitor. The invasive mosquito Aedes albopictus is usually competitively superior to Ochlerotatus triseriatus. Among second instar larvae, A. albopictus show a lesser degree of behavioral modification in response to water-borne cues from predation by the larval midge Corethrella appendiculata than do O. triseriatus, rendering A. albopictus more vulnerable to predation by C. appendiculata than O. triseriatus. The hypothesis that C. appendiculata predation favors coexistence of these competitors predicts that C. appendiculata abundances will be negatively and positively correlated with A. albopictus and O. triseriatus abundances, respectively, and that coexistence will occur where C. appendiculata are common. Actual abundances of O. triseriatus, A. albopictus, and C. appendiculata in three habitats fit this prediction. In natural container habitats like tree holes, C. appendiculata were abundant and competitors co-existed at similar densities. In cemeteries and tires, which occur primarily in non-forested, human-dominated habitats, A. albopictus dominated, with abundances twice those found in tree holes, but C. appendiculata and O. triseriatus were rare or absent. We also tested for whether antipredatory behavioral responses of A. albopictus differed among habitats or populations, or were correlated with local C. appendiculata abundances. We could detect no differences in A. albopictus antipredatory behavioral responses to water-borne cues from predation. Tree hole habitats appear to promote co-existence of O. triseriatus and A. albopictus through interactions with predatory C. appendiculata, and this predator effect appears to limit invasion success of A. albopictus in tree holes. There are many studies on predator-mediated coexistence in natural habitats but to our knowledge this is the first study

  10. Trade-offs, temporal variation, and species coexistence in communities with intraguild predation.

    Science.gov (United States)

    Amarasekare, Priyanga

    2007-11-01

    Intraguild predation/parasitism (IGP: competing species preying on or parasitizing each other) is widespread in nature, but the mechanisms by which intraguild prey and predators coexist remain elusive. Theory predicts that a trade-off between resource competition and IGP should allow local niche partitioning, but such trade-offs are expressed only at intermediate resource productivity and cannot explain observations of stable coexistence at high productivity. Coexistence must therefore involve additional mechanisms beside the trade-off, but very little is known about the operation of such mechanisms in nature. Here I present the first experimental test of multiple coexistence mechanisms in a natural community exhibiting IGP. The results suggest that, when resource productivity constrains the competition-IGP trade-off, a temporal refuge for the intraguild prey can not only promote coexistence, but also change species abundances to a pattern qualitatively different from that expected based on the trade-off or a refuge alone. This is the first empirical study to demonstrate a mechanism for why communities with IGP do not lose species diversity in highly productive environments. These results have implications for diversity maintenance in multi-trophic communities, and the use of multiple natural enemies in biological control.

  11. Polo-like kinase 2 acting as a promoter in human tumor cells with an abundance of TAp73

    Directory of Open Access Journals (Sweden)

    Hu ZB

    2015-11-01

    Full Text Available ZhengBo Hu,1,* ZunYing Xu,1,* XiaoHong Liao,2,* Xiao Yang,1 Cao Dong,1 KuaDi Luk,3 AnMin Jin,1,* Hai Lu4,5,* 1Department of Orthopedics, Zhujiang Hospital of Southern Medical University, 2The State Key Laboratory of Respiratory Diseases, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, 3Department of Orthopedics and Traumatology, The University of Hong Kong, Hong Kong, SAR, 4Department of Orthopedics, the Third Affiliated Hospital of the Southern Medical University, Guangzhou, Guangdong, 5Academy of Orthopedics, Guangdong Province, People’s Republic of China *These authors contributed equally to this work Background: TAp73, a member of the p53 tumor suppressor family, is frequently overexpressed in malignant tumors in humans. TAp73 abundance and phosphorylation modification result in variations in transcriptional activity. In a previous study, we found that the antitumor function of TAp73 was reactivated by dephosphorylation in head and neck squamous cell carcinomas. Polo-like kinase 2 (PLK2 displayed a close relationship with the p53 family in affecting the fate of cells. Herein, we investigate the hypothesis that PLK2 phosphorylates TAp73 and inhibits TAp73 function.Materials and methods: Head and neck squamous cell carcinoma cell lines and osteosarcoma cell lines were used as natural models of the different expression levels of TAp73. Phosphorylation predictor software Scansite 3.0 and the predictor GPS-polo 1.0 were used to analyze the phosphorylation sites. Coimmunoprecipitation, phosphor-tag Western blot, metabolic labeling, and indirect immunofluorescence assays were used to determine the interactions between PLK2 and TAp73. TAp73 activity was assessed by Western blot and reverse transcription polymerase chain reaction, which we used to detect P21 and PUMA, both downstream genes of TAp73. The physiological effects of PLK2 cross talk with TAp73 on cell cycle progress and apoptosis were observed by

  12. All and only CpG containing sequences are enriched in promoters abundantly bound by RNA polymerase II in multiple tissues

    Directory of Open Access Journals (Sweden)

    Myakishev Maxim V

    2008-02-01

    Full Text Available Abstract Background The promoters of housekeeping genes are well-bound by RNA polymerase II (RNAP in different tissues. Although the promoters of these genes are known to contain CpG islands, the specific DNA sequences that are associated with high RNAP binding to housekeeping promoters has not been described. Results ChIP-chip experiments from three mouse tissues, liver, heart ventricles, and primary keratinocytes, indicate that 94% of promoters have similar RNAP binding, ranging from well-bound to poorly-bound in all tissues. Using all 8-base pair long sequences as a test set, we have identified the DNA sequences that are enriched in promoters of housekeeping genes, focusing on those DNA sequences which are preferentially localized in the proximal promoter. We observe a bimodal distribution. Virtually all sequences enriched in promoters with high RNAP binding values contain a CpG dinucleotide. These results suggest that only transcription factor binding sites (TFBS that contain the CpG dinucleotide are involved in RNAP binding to housekeeping promoters while TFBS that do not contain a CpG are involved in regulated promoter activity. Abundant 8-mers that are preferentially localized in the proximal promoters and exhibit the best enrichment in RNAP bound promoters are all variants of six known CpG-containing TFBS: ETS, NRF-1, BoxA, SP1, CRE, and E-Box. The frequency of these six DNA motifs can predict housekeeping promoters as accurately as the presence of a CpG island, suggesting that they are the structural elements critical for CpG island function. Experimental EMSA results demonstrate that methylation of the CpG in the ETS, NRF-1, and SP1 motifs prevent DNA binding in nuclear extracts in both keratinocytes and liver. Conclusion In general, TFBS that do not contain a CpG are involved in regulated gene expression while TFBS that contain a CpG are involved in constitutive gene expression with some CpG containing sequences also involved in

  13. China and Coexistence

    DEFF Research Database (Denmark)

    Odgaard, Liselotte

    “Peaceful coexistence,” long a key phrase in China’s strategic thinking, is a constructive doctrine that offers China a path for influencing the international system. So argues Liselotte Odgaard in this timely analysis of China's national security strategy in the context of its foreign policy...... practice. China’s program of peaceful coexistence emphasizes absolute sovereignty and non-interference in the internal affairs of other states. Odgaard suggests that China’s policy of working within the international community and with non-state actors such as the UN aims to win for China greater power...... and influence without requiring widespread exercise of military or economic pressure. Odgaard examines the origins of peaceful coexistence in early Soviet doctrine, its midcentury development by China and India, and its ongoing appeal to developing countries. She reveals what this foreign policy offers China...

  14. A late embryogenesis abundant protein HVA1 regulated by an inducible promoter enhances root growth and abiotic stress tolerance in rice without yield penalty.

    Science.gov (United States)

    Chen, Yi-Shih; Lo, Shuen-Fang; Sun, Peng-Kai; Lu, Chung-An; Ho, Tuan-Hua D; Yu, Su-May

    2015-01-01

    Regulation of root architecture is essential for maintaining plant growth under adverse environment. A synthetic abscisic acid (ABA)/stress-inducible promoter was designed to control the expression of a late embryogenesis abundant protein (HVA1) in transgenic rice. The background of HVA1 is low but highly inducible by ABA, salt, dehydration and cold. HVA1 was highly accumulated in root apical meristem (RAM) and lateral root primordia (LRP) after ABA/stress treatments, leading to enhanced root system expansion. Water-use efficiency (WUE) and biomass also increased in transgenic rice, likely due to the maintenance of normal cell functions and metabolic activities conferred by HVA1 which is capable of stabilizing proteins, under osmotic stress. HVA1 promotes lateral root (LR) initiation, elongation and emergence and primary root (PR) elongation via an auxin-dependent process, particularly by intensifying asymmetrical accumulation of auxin in LRP founder cells and RAM, even under ABA/stress-suppressive conditions. We demonstrate a successful application of an inducible promoter in regulating the spatial and temporal expression of HVA1 for improving root architecture and multiple stress tolerance without yield penalty.

  15. Bee bread increases honeybee haemolymph protein and promote better survival despite of causing higher Nosema ceranae abundance in honeybees.

    Science.gov (United States)

    Basualdo, Marina; Barragán, Sergio; Antúnez, Karina

    2014-08-01

    Adequate protein nutrition supports healthy honeybees and reduces the susceptibility to disease. However little is known concerning the effect of the diet on Nosema ceranae development, an obligate intracellular parasite that disturbs the protein metabolism of honeybees (Apis mellifera). Here we tested the effect of natural (bee bread) and non-natural protein diets (substitute) on haemolymph proteins titers of honeybee and N. ceranae spore production. The natural diet induced higher levels of protein and parasite development, but the survival of bees was also higher than with non-natural diets. The data showed that the administration of an artificially high nutritious diet in terms of crude protein content is not sufficient to promote healthy bees; rather the protein ingested should be efficiently assimilated. The overall results support the idea that the physiological condition of the bees is linked to protein levels in the haemolymph, which affects the tolerance to parasite; consequently the negative impact of the parasite on host fitness is not associated only with the level of infection.

  16. 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.

  17. 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 mixed...... cultures of the pathogens were grown together in nutrient yeast dextrose broth over a period of 96 h, colonies of P. s. pv. tomato grossly out-numbered those of X. c. pv. vesicatoria, regardless of the ratio in which they were combined. Results of studies with mixed cultures in planta, under screenhouse...... conditions showed similar results. Results of experiments with heat-killed cells of the pathogens showed that heat-killed cells of either of the pathogens were unable to offer cross protection from infection by the other pathogen in susceptible tomato plants...

  18. Coexistence of competitors in marine metacommunities: environmental variability, edge effects, and the dispersal niche.

    Science.gov (United States)

    Aiken, Christopher M; Navarrete, Sergio A

    2014-08-01

    Theoretical studies have shown that coexistence between competitors can be favored in a spatially heterogeneous environment by a number of mechanisms, which ultimately allow the expression of persistent or transitory variation in species competitive abilities, colonization, or reproduction. Four distinctive paradigms to model metacommunities have been identified according to assumptions about the biology of the species and essential aspects of the environment. Missing from these are mechanisms of coexistence that can arise from the dispersal process itself without explicit spatial heterogeneity or biological trade-offs. These mechanisms have only recently received attention, but they may be common in marine communities and other systems in which dispersal is obligatory and modulated by the physical environment. We investigate coexistence in spatially homogeneous metacommunities where there is no partitioning of resources, no competition-colonization trade-off, and no possibility of source-sink dynamics. Coexistence is shown to be possible through three distinct mechanisms related to the dispersal process itself. Firstly, in a neutral scenario, inclusion of temporal variability in the connectivity matrix, emulating an intrinsic attribute of ocean character and other turbulent environments, can promote the invasion of an equally matched competitor and, in a hierarchical competition scenario, the persistence of an otherwise unviable, inferior competitor (the dispersal variability mechanism). Secondly, a sufficiently large difference in the shape of the time-independent dispersal kernels of the two species, which may result from differences in larval-release timing, buoyancy, or behavior, can produce stable coexistence in the center of their shared range (the dispersal-shape mechanism). Thirdly, asymmetry in the dispersal process due to biased advection renders the metapopulation model reactive, such that small variations in the upstream abundances can be sufficient

  19. Opting out against defection leads to stable coexistence with cooperation

    Science.gov (United States)

    Zhang, Bo-Yu; Fan, Song-Jia; Li, Cong; Zheng, Xiu-Deng; Bao, Jian-Zhang; Cressman, Ross; Tao, Yi

    2016-01-01

    Cooperation coexisting with defection is a common phenomenon in nature and human society. Previous studies for promoting cooperation based on kin selection, direct and indirect reciprocity, graph selection and group selection have provided conditions that cooperators outcompete defectors. However, a simple mechanism of the long-term stable coexistence of cooperation and defection is still lacking. To reveal the effect of direct reciprocity on the coexistence of cooperation and defection, we conducted a simple experiment based on the Prisoner’s Dilemma (PD) game, where the basic idea behind our experiment is that all players in a PD game should prefer a cooperator as an opponent. Our experimental and theoretical results show clearly that the strategies allowing opting out against defection are able to maintain this stable coexistence. PMID:27775099

  20. Coexistence of neuropeptides in hydra

    DEFF Research Database (Denmark)

    Grimmelikhuijzen, C J

    1983-01-01

    Using a technique for simultaneous visualisation of two antigens in one section, oxytocin-like immunoreactivity has been found to coexist with bombesin-like immunoreactivity in neurons of the basal disk, gastric region and tentacles of hydra. Neurons with oxytocin-like immunoreactivity in peduncle...... and hypostome, on the other hand, have little or no bombesin-like material. Oxytocin-like immunoreactivity never coexists with FMRFamide-immunoreactivity. The neurons with oxytocin- and FMRFamide-like immunoreactivity, however, are often found to be closely intermingled. The results show that coexistence...

  1. Phenotypic Plasticity and Species Coexistence.

    Science.gov (United States)

    Turcotte, Martin M; Levine, Jonathan M

    2016-10-01

    Ecologists are increasingly interested in predicting how intraspecific variation and changing trait values impact species interactions and community composition. For many traits, much of this variation is caused by phenotypic plasticity, and thus the impact of plasticity on species coexistence deserves robust quantification. Partly due to a lack of sound theoretical expectations, empirical studies make contradictory claims regarding plasticity effects on coexistence. Our critical review of this literature, framed in modern coexistence theory, reveals that plasticity affects species interactions in ways that could impact stabilizing niche differences and competitive asymmetries. However, almost no study integrates these measures to quantify the net effect of plasticity on species coexistence. To address this challenge, we outline novel empirical approaches grounded in modern theory.

  2. Tradeoffs, competition, and coexistence in eastern deciduous forest ant communities.

    Science.gov (United States)

    Stuble, Katharine L; Rodriguez-Cabal, Mariano A; McCormick, Gail L; Jurić, Ivan; Dunn, Robert R; Sanders, Nathan J

    2013-04-01

    Ecologists have long sought to explain the coexistence of multiple potentially competing species in local assemblages. This is especially challenging in species-rich assemblages in which interspecific competition is intense, as it often is in ant assemblages. As a result, a suite of mechanisms has been proposed to explain coexistence among potentially competing ant species: the dominance-discovery tradeoff, the dominance-thermal tolerance tradeoff, spatial segregation, temperature-based niche partitioning, and temporal niche partitioning. Through a series of observations and experiments, we examined a deciduous forest ant assemblage in eastern North America for the signature of each of these coexistence mechanisms. We failed to detect evidence for any of the commonly suggested mechanisms of coexistence, with one notable exception: ant species appear to temporally partition foraging times such that behaviourally dominant species foraged more intensely at night, while foraging by subdominant species peaked during the day. Our work, though focused on a single assemblage, indicates that many of the commonly cited mechanisms of coexistence may not be general to all ant assemblages. However, temporal segregation may play a role in promoting coexistence among ant species in at least some ecosystems, as it does in many other organisms.

  3. Persistent coexistence of cyclically competing species in spatially extended ecosystems

    Science.gov (United States)

    Park, Junpyo; Do, Younghae; Huang, Zi-Gang; Lai, Ying-Cheng

    2013-06-01

    A fundamental result in the evolutionary-game paradigm of cyclic competition in spatially extended ecological systems, as represented by the classic Reichenbach-Mobilia-Frey (RMF) model, is that high mobility tends to hamper or even exclude species coexistence. This result was obtained under the hypothesis that individuals move randomly without taking into account the suitability of their local environment. We incorporate local habitat suitability into the RMF model and investigate its effect on coexistence. In particular, we hypothesize the use of "basic instinct" of an individual to determine its movement at any time step. That is, an individual is more likely to move when the local habitat becomes hostile and is no longer favorable for survival and growth. We show that, when such local habitat suitability is taken into account, robust coexistence can emerge even in the high-mobility regime where extinction is certain in the RMF model. A surprising finding is that coexistence is accompanied by the occurrence of substantial empty space in the system. Reexamination of the RMF model confirms the necessity and the important role of empty space in coexistence. Our study implies that adaptation/movements according to local habitat suitability are a fundamental factor to promote species coexistence and, consequently, biodiversity.

  4. Phase coexistence in nuclei

    Science.gov (United States)

    Gulminelli, F.

    2004-11-01

    In this work the general theory of first order phase transitions in finite systems is discussed, with a special emphasis to the conceptual problems linked to a thermodynamic description for small, short-lived systems de-exciting in the vacuum as nuclear samples coming from heavy ion collisions. After a short review of the general theory of phase transitions in the framework of information theory, we will present the different possible extensions to the field of finite systems. The concept of negative heat capacity, developed in the early seventies in the context of self-gravitating systems, will be reinterpreted in the general framework of convexity anomalies of thermostatistical potentials. The connection with the distribution of the order parameter will lead us to a definition of first order phase transitions in finite systems based on topology anomalies of the event distribution in the space of observations. A careful study of the thermodynamic limit will provide a bridge with the standard theory of phase transitions and show that in a wide class of physical situations the different statistical ensembles are irreducibly inequivalent. In the second part of the paper we will apply the theoretical ideas developed in the first part to the possible observation of a liquid-to-gas-like phase transition in heavy ion collisions. The applicability of equilibrium concepts in a dynamical collisional process without boundary conditions will first be critically discussed. The observation of abnormally large partial energy fluctuations in carefully selected samples of collisions detected with the MULTICS-Miniball and INDRA array will then be reported as a strong evidence of a first order phase transition with negative heat capacity in the nuclear equation of state. Coexistence de phase dans les noyaux Ce papier présente une revue de la théorie générale des transitions de phase du premier ordre dans les petits systèmes, avec une attention particulière aux probl

  5. Welfare and Co-existence

    NARCIS (Netherlands)

    Zilberman, David; Wesseler, J.H.H.

    2016-01-01

    The backlash against the introduction of genetically modified (GM) crops and the concern about contamination of non-GM crops by genetic material originating from GM crops has resulted in a complex and costly legal and physical arrangement for coexistence of GM and non-GM agricultural product systems

  6. Role of intraspecific competition in the coexistence of mobile populations in spatially extended ecosystems.

    Science.gov (United States)

    Yang, Rui; Wang, Wen-Xu; Lai, Ying-Cheng; Grebogi, Celso

    2010-06-01

    Evolutionary-game based models of nonhierarchical, cyclically competing populations have become paradigmatic for addressing the fundamental problem of species coexistence in spatially extended ecosystems. We study the role of intraspecific competition in the coexistence and find that the competition can strongly promote the coexistence for high individual mobility in the sense that stable coexistence can arise in parameter regime where extinction would occur without the competition. The critical value of the competition rate beyond which the coexistence is induced is found to be independent of the mobility. We derive a theoretical model based on nonlinear partial differential equations to predict the critical competition rate and the boundaries between the coexistence and extinction regions in a relevant parameter space. We also investigate pattern formation and well-mixed spatiotemporal population dynamics to gain further insights into our findings.

  7. Competitive intransitivity, population interaction structure, and strategy coexistence.

    Science.gov (United States)

    Laird, Robert A; Schamp, Brandon S

    2015-01-21

    Intransitive competition occurs when competing strategies cannot be listed in a hierarchy, but rather form loops-as in the game rock-paper-scissors. Due to its cyclic competitive replacement, competitive intransitivity promotes strategy coexistence, both in rock-paper-scissors and in higher-richness communities. Previous work has shown that this intransitivity-mediated coexistence is strongly influenced by spatially explicit interactions, compared to when populations are well mixed. Here, we extend and broaden this line of research and examine the impact on coexistence of intransitive competition taking place on a continuum of small-world networks linking spatial lattices and regular random graphs. We use simulations to show that the positive effect of competitive intransitivity on strategy coexistence holds when competition occurs on networks toward the spatial end of the continuum. However, in networks that are sufficiently disordered, increasingly violent fluctuations in strategy frequencies can lead to extinctions and the prevalence of monocultures. We further show that the degree of disorder that leads to the transition between these two regimes is positively dependent on population size; indeed for very large populations, intransitivity-mediated strategy coexistence may even be possible in regular graphs with completely random connections. Our results emphasize the importance of interaction structure in determining strategy dynamics and diversity.

  8. Shape coexistence in 153Ho

    CERN Document Server

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

    2016-01-01

    The high-spin states in 153Ho, have been studied by 139 57 La(20Ne, 6n) reaction at a projectile energy of 139 MeV at Variable Energy Cyclotron Centre (VECC), Kolkata, India, utilizing an earlier campaign of Indian National Gamma Array (INGA) setup. Data from gamma-gamma 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-gamma 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.

  9. A minimum stochastic model evaluating the interplay between population density and drift for species coexistence

    Science.gov (United States)

    Guariento, Rafael Dettogni; Caliman, Adriano

    2017-02-01

    Despite the general acknowledgment of the role of niche and stochastic process in community dynamics, the role of species relative abundances according to both perspectives may have different effects regarding coexistence patterns. In this study, we explore a minimum probabilistic stochastic model to determine the relationship of populations relative and total abundances with species chances to outcompete each other and their persistence in time (i.e., unstable coexistence). Our model is focused on the effects drift (i.e., random sampling of recruitment) under different scenarios of selection (i.e., fitness differences between species). Our results show that taking into account the stochasticity in demographic properties and conservation of individuals in closed communities (zero-sum assumption), initial population abundance can strongly influence species chances to outcompete each other, despite fitness inequalities between populations, and also, influence the period of coexistence of these species in a particular time interval. Systems carrying capacity can have an important role in species coexistence by exacerbating fitness inequalities and affecting the size of the period of coexistence. Overall, the simple stochastic formulation used in this study demonstrated that populations initial abundances could act as an equalizing mechanism, reducing fitness inequalities, which can favor species coexistence and even make less fitted species to be more likely to outcompete better-fitted species, and thus to dominate ecological communities in the absence of niche mechanisms. Although our model is restricted to a pair of interacting species, and overall conclusions are already predicted by the Neutral Theory of Biodiversity, our main objective was to derive a model that can explicitly show the functional relationship between population densities and community mono-dominance odds. Overall, our study provides a straightforward understanding of how a stochastic process (i

  10. Coexistence between wildlife and humans at fine spatial scales.

    Science.gov (United States)

    Carter, Neil H; Shrestha, Binoj K; Karki, Jhamak B; Pradhan, Narendra Man Babu; Liu, Jianguo

    2012-09-18

    Many wildlife species face imminent extinction because of human impacts, and therefore, a prevailing belief is that some wildlife species, particularly large carnivores and ungulates, cannot coexist with people at fine spatial scales (i.e., cannot regularly use the exact same point locations). This belief provides rationale for various conservation programs, such as resettling human communities outside protected areas. However, quantitative information on the capacity and mechanisms for wildlife to coexist with humans at fine spatial scales is scarce. Such information is vital, because the world is becoming increasingly crowded. Here, we provide empirical information about the capacity and mechanisms for tigers (a globally endangered species) to coexist with humans at fine spatial scales inside and outside Nepal's Chitwan National Park, a flagship protected area for imperiled wildlife. Information obtained from field cameras in 2010 and 2011 indicated that human presence (i.e., people on foot and vehicles) was ubiquitous and abundant throughout the study site; however, tiger density was also high. Surprisingly, even at a fine spatial scale (i.e., camera locations), tigers spatially overlapped with people on foot and vehicles in both years. However, in both years, tigers offset their temporal activity patterns to be much less active during the day when human activity peaked. In addition to temporal displacement, tiger-human coexistence was likely enhanced by abundant tiger prey and low levels of tiger poaching. Incorporating fine-scale spatial and temporal activity patterns into conservation plans can help address a major global challenge-meeting human needs while sustaining wildlife.

  11. Early mesozoic coexistence of amniotes and hepadnaviridae.

    Directory of Open Access Journals (Sweden)

    Alexander Suh

    2014-12-01

    Full Text Available Hepadnaviridae are double-stranded DNA viruses that infect some species of birds and mammals. This includes humans, where hepatitis B viruses (HBVs are prevalent pathogens in considerable parts of the global population. Recently, endogenized sequences of HBVs (eHBVs have been discovered in bird genomes where they constitute direct evidence for the coexistence of these viruses and their hosts from the late Mesozoic until present. Nevertheless, virtually nothing is known about the ancient host range of this virus family in other animals. Here we report the first eHBVs from crocodilian, snake, and turtle genomes, including a turtle eHBV that endogenized >207 million years ago. This genomic "fossil" is >125 million years older than the oldest avian eHBV and provides the first direct evidence that Hepadnaviridae already existed during the Early Mesozoic. This implies that the Mesozoic fossil record of HBV infection spans three of the five major groups of land vertebrates, namely birds, crocodilians, and turtles. We show that the deep phylogenetic relationships of HBVs are largely congruent with the deep phylogeny of their amniote hosts, which suggests an ancient amniote-HBV coexistence and codivergence, at least since the Early Mesozoic. Notably, the organization of overlapping genes as well as the structure of elements involved in viral replication has remained highly conserved among HBVs along that time span, except for the presence of the X gene. We provide multiple lines of evidence that the tumor-promoting X protein of mammalian HBVs lacks a homolog in all other hepadnaviruses and propose a novel scenario for the emergence of X via segmental duplication and overprinting of pre-existing reading frames in the ancestor of mammalian HBVs. Our study reveals an unforeseen host range of prehistoric HBVs and provides novel insights into the genome evolution of hepadnaviruses throughout their long-lasting association with amniote hosts.

  12. Coexistence of fisheries with river dolphin conservation.

    Science.gov (United States)

    Kelkar, Nachiket; Krishnaswamy, Jagdish; Choudhary, Sunil; Sutaria, Dipani

    2010-08-01

    Freshwater biodiversity conservation is generally perceived to conflict with human use and extraction (e.g., fisheries). Overexploited fisheries upset the balance between local economic needs and endangered species' conservation. We investigated resource competition between fisheries and Ganges river dolphins (Platanista gangetica gangetica) in a human-dominated river system in India to assess the potential for their coexistence. We surveyed a 65-km stretch of the lower Ganga River to assess habitat use by dolphins (encounter rates) and fishing activity (habitat preferences of fishers, intensity of net and boat use). Dolphin abundance in the main channel increased from 179 (SE 7) (mid dry season) to 270 (SE 8) (peak dry season), probably as a result of immigration from upstream tributaries. Dolphins preferred river channels with muddy, rocky substrates, and deep midchannel waters. These areas overlapped considerably with fishing areas. Sites with 2-6 boats/km (moderately fished) were more preferred by dolphins than sites with 8-55 boats/km (heavily fished). Estimated spatial (85%) and prey-resource overlap (75%) between fisheries and dolphins (chiefly predators of small fish) suggests a high level of competition between the two groups. A decrease in abundance of larger fish, indicated by the fact that small fish comprised 74% of the total caught, may have intensified the present competition. Dolphins seem resilient to changes in fish community structure and may persist in overfished rivers. Regulated fishing in dolphin hotspots and maintenance of adequate dry season flows can sustain dolphins in tributaries and reduce competition in the main river. Fish-stock restoration and management, effective monitoring, curbing destructive fishing practices, secure tenure rights, and provision of alternative livelihoods for fishers may help reconcile conservation and local needs in overexploited river systems.

  13. Species coexistence in a lattice-structured habitat: effects of species dispersal and interactions.

    Science.gov (United States)

    Ying, Zhixia; Liao, Jinbao; Wang, Shichang; Lu, Hui; Liu, Yongjie; Ma, Liang; Li, Zhenqing

    2014-10-21

    Opinions differ on how the spatial distribution of species over space affects species coexistence. Here, we constructed both mean-field and pair approximation (PA) models to explore the effects of interspecific and intraspecific interactions and dispersal modes on species coexistence. We found that spatial structure resulting from species dispersal traits and neighboring interactions in PA model did not promote coexistence if two species had the same traits, though it might intensify the contact frequency of intraspecific competition. If two species adopt different dispersal modes, the spatial structure in PA would make the coexistence or founder control less likely since it alters the species effective birth rate. This suggests that the spatial distribution caused by neighboring interactions and local dispersal does not affect species coexistence unless it adequately alters the effective birth rate for two species. Besides, we modeled how the initial densities and patterns affected population dynamics and revealed how the final spatial pattern was generated.

  14. Coexistence in preferential attachment networks

    CERN Document Server

    Antunović, Tonći; Racz, Miklos Z

    2013-01-01

    Competition in markets is ubiquitous: cell-phone providers, computer manufacturers, and sport gear brands all vie for customers. Though several coexisting competitors are often observed in empirical data, many current theoretical models of competition on small-world networks predict a single winner taking over the majority of the network. We introduce a new model of product adoption that focuses on word-of-mouth recommendations to provide an explanation for this coexistence of competitors. The key property of our model is that customer choices evolve simultaneously with the network of customers. When a new node joins the network, it chooses neighbors according to preferential attachment, and then chooses its type based on the number of initial neighbors of each type. This can model a new cell-phone user choosing a cell-phone provider, a new student choosing a laptop, or a new athletic team member choosing a gear provider. We provide a detailed analysis of the new model; in particular, we determine the possibl...

  15. Shape coexistence at low spin in the Z = 50 region and its spectroscopic signatures

    Science.gov (United States)

    Garrett, P. E.

    2016-08-01

    Nuclei in the Z = 50 region provide excellent examples of shape coexistence, the establishment of which occurred through the use of detailed spectroscopy, based not only on γ-ray spectroscopy but also conversion electron, particle transfer, Coulomb excitation, and lifetime measurements. The evidence to date strongly suggests that the presence of coexisting shapes arises from the promotion of protons across the Z = 50 closed shell and the strong correlations arising from interplay of the pairing and quadrupole interactions. The evidence for the presence of shape coexistence in the Z = 50 region, at low spin and low excitation energies, will be presented and clues for the microscopic origin explored.

  16. Shape coexistence along N = 40

    Energy Technology Data Exchange (ETDEWEB)

    Liddick, S. N. [Michigan State University, East Lansing; Suchyta, S. [Michigan State University, East Lansing; Abromeit, B. [Michigan State University, East Lansing; Ayres, A [University of Tennessee, Knoxville (UTK); Bey, A. [University of Tennessee Medical Center, Knoxville; Bingham, C. R. [University of Tennessee, Knoxville (UTK); Bolla, M [Michigan State University, East Lansing; Carpenter, M. P. [Argonne National Laboratory (ANL); Cartegni, L. [University of Tennessee, Knoxville (UTK); Chiara, C. J. [University of Maryland & Argonne National Laboratory; Crawford, H. L. [Lawrence Berkeley National Laboratory (LBNL); Darby, I. G. [Katholieke University Leuven, Belgium; Grzywacz, R. [University of Tennessee, Knoxville (UTK); Gurdal, G. [Argonne National Laboratory (ANL); Ilyushkin, S. [Mississippi State University (MSU); Larson, N. [Michigan State University, East Lansing; Madurga, M [University of Tennessee, Knoxville (UTK); McCutchan, E. A. [Argonne National Laboratory (ANL); Miller, D [University of Tennessee, Knoxville (UTK); Padgett, Stephen [University of Tennessee, Knoxville (UTK); Paulauskas, S. [University of Tennessee, Knoxville (UTK); Pereira, J. [National Superconducting Cyclotron Laboratory (NSCL); Rajabali, M. M. [Katholieke University Leuven, Belgium; Rykaczewski, Krzysztof Piotr [ORNL; Vinnikova, S. [Michigan State University, East Lansing; Walters, W. B. [University of Maryland; Zhu, S. [Argonne National Laboratory (ANL)

    2011-01-01

    The low-energy level structures of 64 25Mn39 and 66 25Mn41 were investigated through both the decay of Mn metastable states and the population of levels following the decay of 64Cr and 66Cr. The deduced level schemes and tentatively assigned spins and parities suggest the coexistence of spherical and deformed configurations above and below N = 40 for the odd-odd Mn isotopes. The low-energy deformed configurations are attributed to the coupling between a proton in a K = 1/2 level with neutrons in either the K = 1/2 or K = 3/2+ levels originating from the p3/2, p1/2, and g9/2 single-particle states, respectively.

  17. Effect of epidemic spreading on species coexistence in spatial rock-paper-scissors games.

    Science.gov (United States)

    Wang, Wen-Xu; Lai, Ying-Cheng; Grebogi, Celso

    2010-04-01

    A fundamental question in nonlinear science and evolutionary biology is how epidemic spreading may affect coexistence. We address this question in the framework of mobile species under cyclic competitions by investigating the roles of both intra- and interspecies spreading. A surprising finding is that intraspecies infection can strongly promote coexistence while interspecies spreading cannot. These results are quantified and a theoretical paradigm based on nonlinear partial differential equations is derived to explain the numerical results.

  18. Intercultural Counseling: A Perspective to Favor Coexistence in Multicultural Contexts

    Directory of Open Access Journals (Sweden)

    Ana Victoria Garita Pulido

    2014-01-01

    Full Text Available This article refers to the professional practice of Counseling with an intercultural perspective to face multicultural contexts. The paper reflects on coexistence as a social challenge in multicultural contexts and analyzes the importance of culture in the creation of personal identity, and the resulting need for it to be considered in every counseling action. Principles, purposes and characteristics of the intercultural perspective are presented as an integrative model for the attention of cultural diversity, as well as some arguments to define intercultural counseling.  The attitude, knowledge and skills to be developed by counselors to be interculturally competent are also mentioned in the paper. In addition, the study lists all those skills that should be promoted in the counselor’s clients to create a positive coexisting interaction based on their differences.

  19. Voice Deviations and Coexisting Communication Disorders.

    Science.gov (United States)

    St. Louis, Kenneth O.; And Others

    1992-01-01

    This study examined the coexistence of other communicative disorders with voice disorders in about 3,400 children in grades 1-12 at 100 sites throughout the United States. The majority of voice-disordered children had coexisting articulation deviations and also differed from controls on two language measures and mean pure-tone hearing thresholds.…

  20. Effect of non-random dispersal strategies on spatial coexistence mechanisms.

    Science.gov (United States)

    Amarasekare, Priyanga

    2010-01-01

    1. Random dispersal leads to spatial coexistence via two mechanisms (emigration-mediated and source-sink), both of which involve the movement of organisms from areas of higher to lower fitness. What is not known is whether such coexistence would occur if organisms dispersed non-randomly, using cues such as density and habitat quality to gauge fitness differences between habitats. Here, I conduct a comparative analysis of random and non-random dispersal strategies in a foodweb with a basal resource, top predator, and two intermediate consumers that exhibit a trade-off between competitive ability and predator susceptibility. 2. I find a striking contrast between density- and habitat-dependent dispersal in their effects on spatial coexistence. Dispersal in response to competitor and predator density facilitates coexistence while dispersal in response to habitat quality (resource productivity and predator pressure) inhibits it. Moreover, density-dependent dispersal changes species' distribution patterns from interspecific segregation to interspecific aggregation, while habitat-dependent dispersal preserves the interspecific segregation observed in the absence of dispersal. Under density-dependent dispersal, widespread spatial coexistence results in an overall decline in the abundance of the inferior competitor that is less susceptible to predation and an overall increase in the abundance of the superior competitor that is more susceptible to predation. Under habitat-dependent dispersal, restricted spatial coexistence results in species' abundances being essentially unchanged from those observed in the absence of dispersal. 3. A key outcome is that when the superior competitor moves in the direction of increasing fitness but the inferior competitor does not, spatial coexistence is possible in both resource-poor and resource-rich habitats. However, when the inferior competitor moves in the direction of increasing fitness but the superior competitor does not, spatial

  1. Intermittent control of coexisting attractors.

    Science.gov (United States)

    Liu, Yang; Wiercigroch, Marian; Ing, James; Pavlovskaia, Ekaterina

    2013-06-28

    This paper proposes a new control method applicable for a class of non-autonomous dynamical systems that naturally exhibit coexisting attractors. The central idea is based on knowledge of a system's basins of attraction, with control actions being applied intermittently in the time domain when the actual trajectory satisfies a proximity constraint with regards to the desired trajectory. This intermittent control uses an impulsive force to perturb one of the system attractors in order to switch the system response onto another attractor. This is carried out by bringing the perturbed state into the desired basin of attraction. The method has been applied to control both smooth and non-smooth systems, with the Duffing and impact oscillators used as examples. The strength of the intermittent control force is also considered, and a constrained intermittent control law is introduced to investigate the effect of limited control force on the efficiency of the controller. It is shown that increasing the duration of the control action and/or the number of control actuations allows one to successfully switch between the stable attractors using a lower control force. Numerical and experimental results are presented to demonstrate the effectiveness of the proposed method.

  2. Precision mapping of coexisting modifications in histone H3 tails from embryonic stem cells by ETD-MS/MS

    DEFF Research Database (Denmark)

    Jung, Hye Ryung; Sidoli, Simone; Haldbo, Simon

    2013-01-01

    Post-translational modifications (PTMs) of histones play a major role in regulating chromatin dynamics and influence processes such as transcription and DNA replication. Here, we report 114 distinct combinations of coexisting PTMs of histone H3 obtained from mouse embryonic stem (ES) cells. Histone......, and K36, suggesting interdependence between histone methylation marks. We hypothesize that the most abundant coexisting PTMs may provide a signature for the permissive state of mouse ES cells....

  3. Basins of coexistence and extinction in spatially extended ecosystems of cyclically competing species.

    Science.gov (United States)

    Ni, Xuan; Yang, Rui; Wang, Wen-Xu; Lai, Ying-Cheng; Grebogi, Celso

    2010-12-01

    Microscopic models based on evolutionary games on spatially extended scales have recently been developed to address the fundamental issue of species coexistence. In this pursuit almost all existing works focus on the relevant dynamical behaviors originated from a single but physically reasonable initial condition. To gain comprehensive and global insights into the dynamics of coexistence, here we explore the basins of coexistence and extinction and investigate how they evolve as a basic parameter of the system is varied. Our model is cyclic competitions among three species as described by the classical rock-paper-scissors game, and we consider both discrete lattice and continuous space, incorporating species mobility and intraspecific competitions. Our results reveal that, for all cases considered, a basin of coexistence always emerges and persists in a substantial part of the parameter space, indicating that coexistence is a robust phenomenon. Factors such as intraspecific competition can, in fact, promote coexistence by facilitating the emergence of the coexistence basin. In addition, we find that the extinction basins can exhibit quite complex structures in terms of the convergence time toward the final state for different initial conditions. We have also developed models based on partial differential equations, which yield basin structures that are in good agreement with those from microscopic stochastic simulations. To understand the origin and emergence of the observed complicated basin structures is challenging at the present due to the extremely high dimensional nature of the underlying dynamical system.

  4. Cyclic competition of mobile species on continuous space: pattern formation and coexistence.

    Science.gov (United States)

    Ni, Xuan; Wang, Wen-Xu; Lai, Ying-Cheng; Grebogi, Celso

    2010-12-01

    We propose a model for cyclically competing species on continuous space and investigate the effect of the interplay between the interaction range and mobility on coexistence. A transition from coexistence to extinction is uncovered with a strikingly nonmonotonic behavior in the coexistence probability. About the minimum in the probability, switches between spiral and plane-wave patterns arise. A strong mobility can either promote or hamper coexistence, depending on the radius of the interaction range. These phenomena are absent in any lattice-based model, and we demonstrate that they can be explained using nonlinear partial differential equations. Our continuous-space model is more physical and we expect the findings to generate experimental interest.

  5. Evolutionary rescue and the coexistence of generalist and specialist competitors: an experimental test.

    Science.gov (United States)

    Bono, Lisa M; Gensel, Catharine L; Pfennig, David W; Burch, Christina L

    2015-12-22

    Competition for resources is thought to play a critical role in both the origins and maintenance of biodiversity. Although numerous laboratory evolution experiments have confirmed that competition can be a key driver of adaptive diversification, few have demonstrated its role in the maintenance of the resulting diversity. We investigate the conditions that favour the origin and maintenance of alternative generalist and specialist resource-use phenotypes within the same population. Previously, we confirmed that competition for hosts among φ6 bacteriophage in a mixed novel (non-permissive) and ancestral (permissive) host microcosm triggered the evolution of a generalist phenotype capable of infecting both hosts. However, because the newly evolved generalists tended to competitively exclude the ancestral specialists, coexistence between the two phenotypes was rare. Here, we show that reducing the relative abundance of the novel host slowed the increase in frequency of the generalist phenotype, allowing sufficient time for the specialist to further adapt to the ancestral host. This adaptation resulted in 'evolutionary rescue' of the specialists, preventing their competitive exclusion by the generalists. Thus, our results suggest that competition promotes both the origin and maintenance of biodiversity when it is strong enough to favour a novel resource-use phenotype, but weak enough to allow adaptation of both the novel and ancestral phenotypes to their respective niches.

  6. Global minimizers of coexistence for competing species

    OpenAIRE

    2010-01-01

    A class of variational models describing ecological systems of k species competing for the same resources is investigated. The occurrence of coexistence in minimal energy solutions is discussed and positive results are proven for suitably differentiated internal dynamics.

  7. Raccoon abundance inventory report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes the results of a raccoon abundance inventory on Clarence Cannon National Wildlife Refuge in 2012. Determining raccoon abundance allows for...

  8. Relative species abundance of replicator dynamics with sparse interactions

    CERN Document Server

    Obuchi, Tomoyuki; Tokita, Kei

    2016-01-01

    A theory of relative species abundance on sparsely-connected networks is presented by investigating the replicator dynamics with symmetric interactions. Sparseness of a network involves difficulty in analyzing the fixed points of the equation, and we avoid this problem by treating large self interaction $u$, which allows us to construct a perturbative expansion. Based on this perturbation, we find that the nature of the interactions is directly connected to the abundance distribution, and some characteristic behaviors, such as multiple peaks in the abundance distribution and all species coexistence at moderate values of $u$, are discovered in a wide class of the distribution of the interactions. The all species coexistence collapses at a critical value of $u$, $u_c$, and this collapsing is regarded as a phase transition. To get more quantitative information, we also construct a non-perturbative theory on random graphs based on techniques of statistical mechanics. The result shows those characteristic behavior...

  9. Comparative dynamics and life histories of coexisting dragonfly populations

    Energy Technology Data Exchange (ETDEWEB)

    Benke, A.C.; Benke, S.S.

    Several species of coexisting dragonfly larvae were studied for four consecutive years in a 1-ha old farm pond. Larval development, emergence patterns, and adult flight patterns showed that the most abundant species were univoltine and developed relatively synchronously (i.e., like a cohort). Three of the common species emerged in early spring, and the others emerged later in the summer. The common genera with the most similar microhabitat had a distinct temporal separation that may serve in reducing interspecific competition. However, coexisting congeneric species had almost identical life histories, supporting the hypothesis that ecological homologues can coexist because of ''errors of exploitation'' of the dominant species. The larval population dynamics of each dominant species (Ladona deplanata, Epitheca spp., and Celithemis fasciata) was characterized by a constant percentage numerical decline, coupled with with a dramatic biomass increase from time of hatching to final instar. Larval mortality during this period averaged 92 percent per annum, but population biomass increased at least tenfold during the same period for each species. Comparison of larval estimates with emergence data revealed that at least 80 percent of the final instars die just before leaving the water to emerge. Life history variations among species smoothed out composite density and biomass trends which averaged about 1,000 individuals/m/sup 2/ and 2 g dry wt/m/sup 2/, respectively. In general, population dynamics from year to year were quite consistent, indicating a relatively high degree of stability in terms of species composition and densities. (auth)

  10. Linking metacommunity paradigms to spatial coexistence mechanisms.

    Science.gov (United States)

    Shoemaker, Lauren G; Melbourne, Brett A

    2016-09-01

    Four metacommunity paradigms-usually called neutral, species sorting, mass effects, and patch dynamics, respectively-are widely used for empirical and theoretical studies of spatial community dynamics. The paradigm framework highlights key ecological mechanisms operating in metacommunities, such as dispersal limitation, competition-colonization tradeoffs, or species equivalencies. However, differences in coexistence mechanisms between the paradigms and in situations with combined influences of multiple paradigms are not well understood. Here, we create a common model for competitive metacommunities, with unique parameterizations for each metacommunity paradigm and for scenarios with multiple paradigms operating simultaneously. We derive analytical expressions for the strength of Chesson's spatial coexistence mechanisms and quantify these for each paradigm via simulation. For our model, fitness-density covariance, a concentration effect measuring the importance of intraspecific aggregation of individuals, is the dominant coexistence mechanism in all three niche-based metacommunity paradigms. Increased dispersal between patches erodes intraspecific aggregation, leading to lower coexistence strength in the mass effects paradigm compared to species sorting. Our analysis demonstrates the potential importance of aggregation of individuals (fitness-density covariance) over co-variation in abiotic environments and competition between species (the storage effect), as fitness-density covariance can be stronger than the storage effect and is the sole stabilizing mechanism in the patch dynamics paradigm. As expected, stable coexistence does not occur in the neutral paradigm, which requires species to be equal and emphasizes the role of stochasticity. We show that stochasticity also plays an important role in niche-structured metacommunities by altering coexistence strength. We conclude that Chesson's spatial coexistence mechanisms provide a flexible framework for comparing

  11. Adaptive and variable intraguild predators facilitate local coexistence in an intraguild predation module.

    Science.gov (United States)

    Wu, San-He; Okuyama, Toshinori

    2012-05-24

    Intraguild predation (IGP) is common in nature, but its ecological role is still illusive. A number of studies have investigated a three species IGP module that consists of an intraguild predator, intraguild prey, and resource species in which the intraguild predator and the intraguild prey exploitatively compete for the resource while the intraguild predator also consumes the intraguild prey. A common prediction of models of the IGP module is that the coexistence of the species is difficult, which is considered inconsistent to the ubiquity of IGP in nature. This study revisits the IGP module and provides an alternative coexistence mechanism by focusing on a commonly used analysis method (i.e., invasion analysis) in light of individual variation in adaptive behavior. Invasion analysis underestimates the possibility of coexistence regardless of the presence or absence of adaptive behavior. Coexistence is possible even when invasion analysis predicts otherwise. The underestimation by invasion analysis is pronounced when the intraguild predator forages adaptively, which is even further pronounced when the expression of foraging behavior is variable among intraguild predators. The possibility of coexistence in the IGP module is greater than previously thought, which may have been partly due to how models were analyzed. Inconsistent conclusions may result from the same model depending on how the model is analyzed. Individual variation in adaptive behavior can be an important factor promoting the coexistence of species in IGP modules.

  12. 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…

  13. The Current Status of Religious Coexistence and Education in Bosnia and Herzegovina. USIPeace Briefing

    Science.gov (United States)

    Stuebner, Renata

    2009-01-01

    Despite 15 years of sporadic efforts, religion today in Bosnia and Herzegovina is more of a hindrance than a help to promoting peaceful coexistence among the region's various ethnic and religious groups. Polarization and extremism make religions other than one's own even more distant, strange and threatening. Physical interaction that existed…

  14. 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…

  15. 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.

  16. 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

  17. Solvable model for template coexistence in protocells

    CERN Document Server

    Fontanari, J F

    2012-01-01

    Compartmentalization of self-replicating molecules (templates) in protocells is a necessary step towards the evolution of modern cells. However, coexistence between distinct template types inside a protocell can be achieved only if there is a selective pressure favoring protocells with a mixed template composition. Here we study analytically a group selection model for the coexistence between two template types using the diffusion approximation of population genetics. The model combines competition at the template and protocell levels as well as genetic drift inside protocells. At the steady state, we find a continuous phase transition separating the coexistence and segregation regimes, with the order parameter vanishing linearly with the distance to the critical point. In addition, we derive explicit analytical expressions for the critical steady-state probability density of protocell compositions.

  18. Solvable model for template coexistence in protocells

    Science.gov (United States)

    Fontanari, J. F.; Serva, M.

    2013-02-01

    Compartmentalization of self-replicating molecules (templates) in protocells is a necessary step towards the evolution of modern cells. However, coexistence between distinct template types inside a protocell can be achieved only if there is a selective pressure favoring protocells with a mixed template composition. Here we study analytically a group selection model for the coexistence between two template types using the diffusion approximation of population genetics. The model combines competition at the template and protocell levels as well as genetic drift inside protocells. At the steady state, we find a continuous phase transition separating the coexistence and segregation regimes, with the order parameter vanishing linearly with the distance to the critical point. In addition, we derive explicit analytical expressions for the critical steady-state probability density of protocell compositions.

  19. Precision Chemical Abundance Measurements

    DEFF Research Database (Denmark)

    Yong, David; Grundahl, Frank; Meléndez, Jorge;

    2012-01-01

    This talk covers preliminary work in which we apply a strictly differential line-by-line chemical abundance analysis to high quality UVES spectra of the globular cluster NGC 6752. We achieve extremely high precision in the measurement of relative abundance ratios. Our results indicate that the ob......This talk covers preliminary work in which we apply a strictly differential line-by-line chemical abundance analysis to high quality UVES spectra of the globular cluster NGC 6752. We achieve extremely high precision in the measurement of relative abundance ratios. Our results indicate...... that the observed abundance dispersion exceeds the measurement uncertainties and that many pairs of elements show significant correlations when plotting [X1/H] vs. [X2/H]. Our tentative conclusions are that either NGC 6752 is not chemically homogeneous at the ~=0.03 dex level or the abundance variations...

  20. Relative species abundance of replicator dynamics with sparse interactions

    Science.gov (United States)

    Obuchi, Tomoyuki; Kabashima, Yoshiyuki; Tokita, Kei

    2016-11-01

    A theory of relative species abundance on sparsely-connected networks is presented by investigating the replicator dynamics with symmetric interactions. Sparseness of a network involves difficulty in analyzing the fixed points of the equation, and we avoid this problem by treating large self interaction u, which allows us to construct a perturbative expansion. Based on this perturbation, we find that the nature of the interactions is directly connected to the abundance distribution, and some characteristic behaviors, such as multiple peaks in the abundance distribution and all species coexistence at moderate values of u, are discovered in a wide class of the distribution of the interactions. The all species coexistence collapses at a critical value of u, u c , and this collapsing is regarded as a phase transition. To get more quantitative information, we also construct a non-perturbative theory on random graphs based on techniques of statistical mechanics. The result shows those characteristic behaviors are sustained well even for not large u. For even smaller values of u, extinct species start to appear and the abundance distribution becomes rounded and closer to a standard functional form. Another interesting finding is the non-monotonic behavior of diversity, which quantifies the number of coexisting species, when changing the ratio of mutualistic relations Δ . These results are examined by numerical simulations, which show that our theory is exact for the case without extinct species, but becomes less and less precise as the proportion of extinct species grows.

  1. 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.

  2. 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

  3. 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...

  4. Cascading effects of defaunation on the coexistence of two specialized insect seed predators.

    Science.gov (United States)

    Peguero, Guille; Muller-Landau, Helene C; Jansen, Patrick A; Wright, S Joseph

    2017-01-01

    Identification of the mechanisms enabling stable coexistence of species with similar resource requirements is a central challenge in ecology. Such coexistence can be facilitated by species at higher trophic levels through complex multi-trophic interactions, a mechanism that could be compromised by ongoing defaunation. We investigated cascading effects of defaunation on Pachymerus cardo and Speciomerus giganteus, the specialized insect seed predators of the Neotropical palm Attalea butyracea, testing the hypothesis that vertebrate frugivores and granivores facilitate their coexistence. Laboratory experiments showed that the two seed parasitoid species differed strongly in their reproductive ecology. Pachymerus produced many small eggs that it deposited exclusively on the fruit exocarp (exterior). Speciomerus produced few large eggs that it deposited exclusively on the endocarp, which is normally exposed only after a vertebrate handles the fruit. When eggs of the two species were deposited on the same fruit, Pachymerus triumphed only when it had a long head start, and the loser always succumbed to intraguild predation. We collected field data on the fates of 6569 Attalea seeds across sites in central Panama with contrasting degrees of defaunation and wide variation in the abundance of vertebrate frugivores and granivores. Speciomerus dominated where vertebrate communities were intact, whereas Pachymerus dominated in defaunated sites. Variation in the relative abundance of Speciomerus across all 84 sampling sites was strongly positively related to the proportion of seeds attacked by rodents, an indicator of local vertebrate abundance.

  5. 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

  6. 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

  7. Trait-based tests of coexistence mechanisms.

    Science.gov (United States)

    Adler, Peter B; Fajardo, Alex; Kleinhesselink, Andrew R; Kraft, Nathan J B

    2013-10-01

    Recent functional trait studies have shown that trait differences may favour certain species (environmental filtering) while simultaneously preventing competitive exclusion (niche partitioning). However, phenomenological trait-dispersion analyses do not identify the mechanisms that generate niche partitioning, preventing trait-based prediction of future changes in biodiversity. We argue that such predictions require linking functional traits with recognised coexistence mechanisms involving spatial or temporal environmental heterogeneity, resource partitioning and natural enemies. We first demonstrate the limitations of phenomenological approaches using simulations, and then (1) propose trait-based tests of coexistence, (2) generate hypotheses about which plant functional traits are likely to interact with particular mechanisms and (3) review the literature for evidence for these hypotheses. Theory and data suggest that all four classes of coexistence mechanisms could act on functional trait variation, but some mechanisms will be stronger and more widespread than others. The highest priority for future research is studies of interactions between environmental heterogeneity and trait variation that measure environmental variables at within-community scales and quantify species' responses to the environment in the absence of competition. Evidence that similar trait-based coexistence mechanisms operate in many ecosystems would simplify biodiversity forecasting and represent a rare victory for generality over contingency in community ecology.

  8. How variation between individuals affects species coexistence.

    Science.gov (United States)

    Hart, Simon P; Schreiber, Sebastian J; Levine, Jonathan M

    2016-08-01

    Although the effects of variation between individuals within species are traditionally ignored in studies of species coexistence, the magnitude of intraspecific variation in nature is forcing ecologists to reconsider. Compelling intuitive arguments suggest that individual variation may provide a previously unrecognised route to diversity maintenance by blurring species-level competitive differences or substituting for species-level niche differences. These arguments, which are motivating a large body of empirical work, have rarely been evaluated with quantitative theory. Here we incorporate intraspecific variation into a common model of competition and identify three pathways by which this variation affects coexistence: (1) changes in competitive dynamics because of nonlinear averaging, (2) changes in species' mean interaction strengths because of variation in underlying traits (also via nonlinear averaging) and (3) effects on stochastic demography. As a consequence of the first two mechanisms, we find that intraspecific variation in competitive ability increases the dominance of superior competitors, and intraspecific niche variation reduces species-level niche differentiation, both of which make coexistence more difficult. In addition, individual variation can exacerbate the effects of demographic stochasticity, and this further destabilises coexistence. Our work provides a theoretical foundation for emerging empirical interests in the effects of intraspecific variation on species diversity.

  9. Multiple peaks of species abundance distributions induced by sparse interactions

    CERN Document Server

    Obuchi, Tomoyuki; Tokita, Kei

    2016-01-01

    We investigate the replicator dynamics with "sparse" symmetric interactions which represent specialist-specialist interactions in ecological communities. By considering a large self interaction $u$, we conduct a perturbative expansion which manifests that the nature of the interactions has a direct impact on the species abundance distribution. The central results are all species coexistence in a realistic range of the model parameters and that a certain discrete nature of the interactions induces multiple peaks in the species abundance distribution, providing the possibility of theoretically explaining multiple peaks observed in various field studies. To get more quantitative information, we also construct a non-perturbative theory which becomes exact on tree-like networks if all the species coexist, providing exact critical values of $u$ below which extinct species emerge. Numerical simulations in various different situations are conducted and they clarify the robustness of the presented mechanism of all spe...

  10. Requirements for plant coexistence through pollination niche partitioning.

    Science.gov (United States)

    Benadi, Gita

    2015-07-07

    Plant-pollinator interactions are often thought to have been a decisive factor in the diversification of flowering plants, but to be of little or no importance for the maintenance of existing plant diversity. In a recent opinion paper, Pauw (2013 Trends Ecol. Evol. 28, 30-37. (doi:10.1016/j.tree.2012.07.019)) challenged this view by proposing a mechanism of diversity maintenance based on pollination niche partitioning. In this article, I investigate under which conditions the mechanism suggested by Pauw can promote plant coexistence, using a mathematical model of plant and pollinator population dynamics. Numerical simulations show that this mechanism is most effective when the costs of searching for flowers are low, pollinator populations are strongly limited by resources other than pollen and nectar, and plant-pollinator interactions are sufficiently specialized. I review the empirical literature on these three requirements, discuss additional factors that may be important for diversity maintenance through pollination niche partitioning, and provide recommendations on how to detect this coexistence mechanism in natural plant communities.

  11. Effect of Barium Oxide on the Formation and Coexistence of Tricalcium Silicate and Calcium Sulphoaluminate

    Institute of Scientific and Technical Information of China (English)

    CHEN Lin; SHEN Xiaodong; MA Suhua; HUANG Yeping; ZHONG Baiqian

    2009-01-01

    Formation and coexistence of tricalcium silicate(C_3S)and calcium sulphoaluminate (C_4 A 3(S))minerals in Portland cement clinker containing calcium sulphoaluminate were investigated. The f-CaO content,mineral composite and formation of mineral in the clinker were analyzed respectively by chemical analysis,differential scanning calorimetry(DSC)and X-ray diffraction.The results show that,adding a suitable amount of BaO can improve the burnability of raw meal and promote the f-CaO absorption.Tricalcium silicate and calcium sulphoaluminate minerals can form and coexist in clinkers at 1 234-1 317 ℃by the addition of BaO to the raw meal.A suitable amount of BaO expanded the coexistence temperature of two minerals by 58℃.

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

    DEFF Research Database (Denmark)

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

    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...... 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...... 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...

  13. Coexistence in streams: do source-sink dynamics allow salamanders to persist with fish predators?

    Science.gov (United States)

    Sepulveda, Adam J; Lowe, Winsor H

    2011-08-01

    Theory suggests that source-sink dynamics can allow coexistence of intraguild predators and prey, but empirical evidence for this coexistence mechanism is limited. We used capture-mark-recapture, genetic methods, and stable isotopes to test whether source-sink dynamics promote coexistence between stream fishes, the intraguild predator, and stream salamanders (Dicamptodon aterrimus), the intraguild prey. Salamander populations from upstream reaches without fish were predicted to maintain or supplement sink populations in downstream reaches with fish. We found instead that downstream reaches with fish were not sinks even though fish consumed salamander larvae-apparent survival, recruitment, and population growth rate did not differ between upstream and downstream reaches. There was also no difference between upstream and downstream reaches in net emigration. We did find that D. aterrimus moved frequently along streams, but believe that this is a response to seasonal habitat changes rather than intraguild predation. Our study provides empirical evidence that local-scale mechanisms are more important than dispersal dynamics to coexistence of streams salamanders and fish. More broadly, it shows the value of empirical data on dispersal and gene flow for distinguishing between local and spatial mechanisms of coexistence.

  14. Life-cycle switching and coexistence of species with no niche differentiation.

    Directory of Open Access Journals (Sweden)

    Javier Montero-Pau

    Full Text Available The increasing evidence of coexistence of cryptic species with no recognized niche differentiation has called attention to mechanisms reducing competition that are not based on niche-differentiation. Only sex-based mechanisms have been shown to create the negative feedback needed for stable coexistence of competitors with completely overlapping niches. Here we show that density-dependent sexual and diapause investment can mediate coexistence of facultative sexual species having identical niches. We modelled the dynamics of two competing cyclical parthenogens with species-specific density-dependent sexual and diapause investment and either equal or different competitive abilities. We show that investment in sexual reproduction creates an opportunity for other species to invade and become established. This may happen even if the invading species is an inferior competitor. Our results suggests a previously unnoticed mechanism for species coexistence and can be extended to other facultative sexual species and species investing in diapause where similar density-dependent life-history switches could act to promote coexistence.

  15. 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.

  16. Theoretical study of coexistence of ordering and spinodal decomposition

    Institute of Scientific and Technical Information of China (English)

    任晓兵; 王笑天; T.Tadaki; K.Shimizu

    1996-01-01

    According to the conventional theory of solid solutions (the nearest neighbor atomic interaction model),ordering and spinodal decomposition/clustering are mutually exclusive processes.However,it has been found that the coexistence of ordering and spinodal decomposition (COSD) occurs in a large number of alloys.This fact gave a strong challenge to the conventional theory.A statistical investigation revealed that the COSD was closely related to large atomic-siae factors.It was thus proposed that the COSD stemmed from the long-range elastic interactions due to atomic-si?E disparity.In order to verify this idea,the formulism of concentration waves was applied to calculating the elastic interactions.The results proved that long-range atomic elastic interactions promoted both ordering and spinodal decomposition.A possible application of the COSD reaction was proposed,i.e.using this reaction to fabricate high-performance "natural nano-alloys".

  17. Good Fences: The Importance of Setting Boundaries for Peaceful Coexistence

    CERN Document Server

    Rutherford, Alex; Werfel, Justin; Bar-Yam, Shlomiya; Gard-Murray, Alexander; Gros, Andreas; Bar-Yam, Yaneer

    2011-01-01

    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. 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 either guarant...

  18. 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.

  19. OXYGEN ABUNDANCES IN CEPHEIDS

    Energy Technology Data Exchange (ETDEWEB)

    Luck, R. E.; Andrievsky, S. M. [Department of Astronomy, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106-7215 (United States); Korotin, S. N.; Kovtyukh, V. V., E-mail: luck@fafnir.astr.cwru.edu, E-mail: serkor@skyline.od.ua, E-mail: val@deneb1.odessa.ua, E-mail: scan@deneb1.odessa.ua [Department of Astronomy and Astronomical Observatory, Odessa National University, Isaac Newton Institute of Chile, Odessa Branch, Shevchenko Park, 65014 Odessa (Ukraine)

    2013-07-01

    Oxygen abundances in later-type stars, and intermediate-mass stars in particular, are usually determined from the [O I] line at 630.0 nm, and to a lesser extent, from the O I triplet at 615.7 nm. The near-IR triplets at 777.4 nm and 844.6 nm are strong in these stars and generally do not suffer from severe blending with other species. However, these latter two triplets suffer from strong non-local thermodynamic equilibrium (NLTE) effects and thus see limited use in abundance analyses. In this paper, we derive oxygen abundances in a large sample of Cepheids using the near-IR triplets from an NLTE analysis, and compare those abundances to values derived from a local thermodynamic equilibrium (LTE) analysis of the [O I] 630.0 nm line and the O I 615.7 nm triplet as well as LTE abundances for the 777.4 nm triplet. All of these lines suffer from line strength problems making them sensitive to either measurement complications (weak lines) or to line saturation difficulties (strong lines). Upon this realization, the LTE results for the [O I] lines and the O I 615.7 nm triplet are in adequate agreement with the abundance from the NLTE analysis of the near-IR triplets.

  20. 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.

  1. Phase coexistence in a forecasting game

    CERN Document Server

    Curty, P; Curty, Philippe; Marsili, Matteo

    2005-01-01

    Individual choices are either based on personal experience or on information provided by peers. The latter case, causes individuals to conform to the majority in their neighborhood. Such herding behavior may be very efficient in aggregating disperse private information, thereby revealing the optimal choice. However if the majority relies on herding, this mechanism may dramatically fail to aggregate correctly the information, causing the majority adopting the wrong choice. We address these issues in a simple model of interacting agents who aim at giving a correct forecast of a public variable, either seeking private information or resorting to herding. As the fraction of herders increases, the model features a phase transition beyond which a state where most agents make the correct forecast coexists with one where most of them are wrong. Simple strategic considerations suggest that indeed such a system of agents self-organizes deep in the coexistence region. There, agents tend to agree much more among themselv...

  2. Co-existence of agricultural production systems.

    Science.gov (United States)

    Jank, Bernhard; Rath, Johannes; Gaugitsch, Helmut

    2006-05-01

    Strategies and best practices for the co-existence of GM and non-GM crops need to be developed and implemented with the participation of farmers and other stakeholders. According to the principle of 'subsidiarity', decisions should be made by the lowest authority possible. When applying this concept to the case of GM crops, the affected society should determine their use and management in a regional decision-making process. Public participation is better accomplished at a lower level, and democratic deficits in decision-making on GMOs are better resolved, enabling farmers to manage or avoid GM crops. Ultimately, voluntary GMO-free zones might be a tool for sustainable co-existence and GM-free production and GMO-free zones might create a specific image for marketing regional products and services, such as tourism.

  3. Gastric schwannoma coexists with peptic ulcer perforation

    Directory of Open Access Journals (Sweden)

    Volkan İnce

    2011-09-01

    Full Text Available Gastric schwannoma is a benign neoplasm that originates from sheet of nerve cell in stomach. Differential diagnosis of gastrointestinal stromal tumors, (GISTs which have malign potential, than these tumors, which definite diagnosis is determined by histopathological and immunohistochemical methods have clinical significance due to gastric schwannomas have excellent progress after surgical resection. We presented a case of gastric schwannoma coexists with peptic ulcer perforation with guide of literature in this study.

  4. On the coexistence of reciprocity and materialism

    OpenAIRE

    Akiko Maruyama

    2007-01-01

    This paper studies the problem of the long-run preferences distribution in a large population using an evolutionary approach. Special attention is given to the investigation of the property of the mixed population equilibria, in which materialists and reciprocators coexist. Some of the players with reciprocal preference care about not only their own material payoffs but also about those of others, while the remaining ones are materialists who maximize their own material payoffs.

  5. Coexisting typical migraine in familial hemiplegic migraine.

    Science.gov (United States)

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

    2010-02-16

    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. The study design was a balanced provocation study. Twenty-three patients with FHM and 11 healthy controls received a continuous IV infusion of 0.5 mug/kg/min GTN over 20 minutes. We found no difference in the incidence of migraine-like attacks comparing all patients with FHM (30%) to controls (9%) (p = 0.15). Patients with FHM with coexisting MA or MO reported more migraine attacks after GTN (55%) than patients with the pure FHM phenotype (8.3%) (p = 0.02). Compared to healthy controls, more patients with FHM with coexisting MA or MO reported migraine-like attacks than controls (p = 0.03), whereas the FHM group with the pure FHM phenotype did not (p > 0.05). Compared to patients with migraine with aura (MA) and migraine without aura (MO), patients with familial hemiplegic migraine (FHM) without known gene mutations display a reduced sensitivity to nitric oxide. A subset of patients with FHM with coexisting nonhemiplegic migraine is more sensitive than controls. These data extend our previous findings that pathophysiologic pathways in FHM may differ from those of MO and MA.

  6. 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.

  7. 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

  8. Tuberous sclerosis complex coexistent with hippocampal sclerosis.

    Science.gov (United States)

    Lang, Min; Prayson, Richard A

    2016-02-01

    Tuberous sclerosis and hippocampal sclerosis are both well-defined entities associated with medically intractable epilepsy. To our knowledge, there has been only one prior case of these two pathologies being co-existent. We report a 7-month-old boy who presented with intractable seizures at 2 months of age. MRI studies showed diffuse volume loss in the brain with bilateral, multiple cortical tubers and subcortical migration abnormalities. Subependymal nodules were noted without subependymal giant cell astrocytoma. Genetic testing revealed TSC2 and PRD gene deletions. Histopathology of the hippocampus showed CA1 sclerosis marked by loss of neurons in the CA1 region. Sections from the temporal, parietal and occipital lobes showed multiple cortical tubers characterized by cortical architectural disorganization, gliosis, calcifications and increased number of large balloon cells. Focal white matter balloon cells and spongiform changes were also present. The patient underwent resection of the right fronto-parietal lobe and a subsequent resection of the right temporal, parietal and occipital lobes. The patient is free of seizures on anti-epileptic medication 69 months after surgery. Although hippocampal sclerosis is well documented to be associated with coexistent focal cortical dysplasia, the specific co-existence of cortical tubers and hippocampal sclerosis appears to be rare.

  9. Species coexistence in a changing world

    Directory of Open Access Journals (Sweden)

    Fernando eValladares

    2015-10-01

    Full Text Available 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.

  10. The shape of terrestrial abundance distributions.

    Science.gov (United States)

    Alroy, John

    2015-09-01

    Ecologists widely accept that the distribution of abundances in most communities is fairly flat but heavily dominated by a few species. The reason for this is that species abundances are thought to follow certain theoretical distributions that predict such a pattern. However, previous studies have focused on either a few theoretical distributions or a few empirical distributions. I illustrate abundance patterns in 1055 samples of trees, bats, small terrestrial mammals, birds, lizards, frogs, ants, dung beetles, butterflies, and odonates. Five existing theoretical distributions make inaccurate predictions about the frequencies of the most common species and of the average species, and most of them fit the overall patterns poorly, according to the maximum likelihood-related Kullback-Leibler divergence statistic. Instead, the data support a low-dominance distribution here called the "double geometric." Depending on the value of its two governing parameters, it may resemble either the geometric series distribution or the lognormal series distribution. However, unlike any other model, it assumes both that richness is finite and that species compete unequally for resources in a two-dimensional niche landscape, which implies that niche breadths are variable and that trait distributions are neither arrayed along a single dimension nor randomly associated. The hypothesis that niche space is multidimensional helps to explain how numerous species can coexist despite interacting strongly.

  11. Deuterium abundance and cosmology

    CERN Document Server

    Vidal-Madjar, A; Lemoine, M

    1996-01-01

    We review the status of the measurements of the deuterium abundance from the local interstellar medium to the solar system and high redshifts absorbers toward quasars. We present preliminary results toward a white dwarf and a QSO. We conclude that the deuterium evolution from the Big-Bang to now is still not properly understood.

  12. A Hydration-Based Biophysical Index for the Onset of Soil Microbial Coexistence

    OpenAIRE

    Gang Wang; Dani Or

    2012-01-01

    Mechanistic exploration of the origins of the unparalleled soil microbial biodiversity represents a vast and uncharted scientific frontier. Quantification of candidate mechanisms that promote and sustain such diversity must be linked with microbial functions and measurable biophysical interactions at appropriate scales. We report a novel microbial coexistence index (CI) that links macroscopic soil hydration conditions with microscale aquatic habitat fragmentation that impose restrictions on c...

  13. 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.

  14. Inter-WBAN Coexistence and Interference Mitigation

    Institute of Scientific and Technical Information of China (English)

    Bin Liu; Xiaosong Zhao; Lei Zou; Chang Wen Chen

    2015-01-01

    With promising applications in e⁃health and entertainment, wireless body area networks (WBANs) have attracted the in⁃terest of both academia and industry. If WBANs are densely deployed within a small area, serious problems may arise be⁃tween the WBANs. In this paper, we discuss issues related to the coexistence of WBANs and investigate the main fac⁃tors that cause inter⁃WBAN interference. We survey inter⁃WBAN interference mitigation strategies and track recent re⁃search developments. We also discuss unresolved issues re⁃lated to inter⁃WBAN interference mitigation and propose fu⁃ture research directions.

  15. Evidence for shape coexistence in $^{98}$Mo

    CERN Document Server

    Thomas, T; Werner, V; Ahn, T; Cooper, N; Duckwitz, H; Hinton, M; Ilie, G; Jolie, J; Petkov, P; Radeck, D

    2013-01-01

    A $\\gamma\\gamma$ angular correlation experiment has been performed to investigate the low-energy states of the nucleus $^{98}$Mo. The new data, including spin assignments, multipole mixing ratios and lifetimes reveal evidence for shape coexistence and mixing in $^{98}$Mo, arising from a proton intruder configuration. This result is reproduced by a theoretical calculation within the proton-neutron interacting boson model with configuration mixing, based on microscopic energy density functional theory. The microscopic calculation indicates the importance of the proton particle-hole excitation across the Z=40 sub-shell closure and the subsequent mixing between spherical vibrational and the $\\gamma$-soft equilibrium shapes in $^{98}$Mo.

  16. Interfaces in coexisting metals and Mott insulators

    Science.gov (United States)

    Lee, Juho; Yee, Chuck-Hou

    2017-05-01

    Motivated by the direct observation of electronic phase separation in first-order Mott transitions, we model the interface between thermodynamically coexisting metals and Mott insulators. We show how to model the required slab geometry and extract the electronic spectra. We construct an effective Landau free energy and compute the variation of its parameters across the phase diagram. Finally, using a linear mixture of the density and double occupancy, we identify a natural Ising order parameter which unifies the treatment of the bandwidth and filling controlled Mott transitions.

  17. Coexisting typical migraine in familial hemiplegic migraine

    DEFF Research Database (Denmark)

    Hansen, Jakob Møller; Olesen, Jes; Ashina, Messoud

    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....

  18. 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....

  19. Coexistence of papillary carcinoma and Hashimoto's thyroiditis.

    Science.gov (United States)

    Matesa-Anić, Dubravka; Matesa, Neven; Dabelić, Nina; Kusić, Zvonko

    2009-03-01

    The aim of the study was to determine the incidence of coexistence of papillary carcinoma and Hashimoto's thyroiditis in cytologic material. Cytologic findings were collected from 10508 patients that underwent ultrasound-guided fine needle aspiration cytology (FNAC) of the thyroid. Hashimoto's thyroiditis was found in 2156 (20.5%) and papillary carcinoma in 269 (2.6%) of 10508 patients with FNAC, whereas both Hashimoto's thyroiditis and papillary carcinoma were present in 42 (0.4%) patients. Among patients with FNAC diagnosis of Hashimoto's thyroiditis, the prevalence of papillary carcinoma was 1.9%. Among patients with FNAC diagnosis of papillary carcinoma, the prevalence of Hashimoto's thyroiditis was 15.6%. There was no statistically significant association between the presence of papillary carcinoma and Hashimoto's thyroiditis in patients undergoing FNAC (p=0.0522). In conclusion, in a large series of patients, the incidence of Hashimoto's thyroiditis and papillary carcinoma coexistence in cytologic material was 0.4%. There was no statistically significant relationship between Hashimoto's thyroiditis and papillary carcinoma in cytologic material.

  20. Honeybee (Apis mellifera L.) mrjp gene family: computational analysis of putative promoters and genomic structure of mrjp1, the gene coding for the most abundant protein of larval food.

    Science.gov (United States)

    Malecová, Barbora; Ramser, Juliane; O'Brien, John K; Janitz, Michal; Júdová, Jana; Lehrach, Hans; Simúth, Jozef

    2003-01-16

    Mrjp1 gene belongs to the honeybee mrjp gene family encoding the major royal jelly proteins (MRJPs), secreted by nurse bees into the royal jelly. In this study, we have isolated the genomic clone containing the entire mrjp1 gene and determined its sequence. The mrjp1 gene sequence spans over 3038 bp and contains six exons separated by five introns. Seven mismatches between the mrjp1 gene sequence and two previously independently published cDNA sequences were found, but these differences do not lead to any change in the deduced amino acid sequence of MRJP1. With the aid of inverse polymerase chain reaction we obtained sequences flanking the 5' ends of other mrjp genes (mrjp2, mrjp3, mrjp4 and mrjp5). Putative promoters were predicted upstream of all mrjp genes (including mrjp1). The predicted promoters contain the TATA motif (TATATATT), highly conserved both in sequence and position. Ultraspiracle (USP) transcription factor (TF) binding sites in putative promoter regions and clusters of dead ringer TF binding sites upstream of these promoters were predicted computationally. We propose that USP, as a juvenile hormone (JH) binding TF, might possibly act as a mediator of mrjp expression in response to JH. Mrjp1's genomic locus is predicted to encode an antisense transcript, partially overlapping with five mrjp1 exons and entirely overlapping with the putative promoter and predicted transcriptional start point of mrjp1. This finding may shed light on the mechanisms of regulation of mrjps expression. Southern blot analysis of genomic DNA revealed that all so far known members of mrjp gene family (mrjp1, mrjp2, mrjp3, mrjp4 and mrjp5) are present as single-copy genes per haploid honeybee genome. Although MRJPs and the yellow protein of Drosophila melanogaster share a certain degree of similarity in aa sequence and although it has been shown that they share a common evolutionary origin, neither structural similarities in the gene organization, nor significant similarities

  1. 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...... 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....

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

    Indian Academy of Sciences (India)

    P Chaddah; A Banerjee

    2008-02-01

    We discuss our very interesting experimental observation that the low-temperature two-phase coexistence in half-doped manganites is multi-valued (at any field) in that we can tune the coexisting antiferromagnetic-insulating (AF-I) and the ferromagnetic-metallic (FM-M) phase fractions by following different paths in (; ) space. We have shown experimentally that the phase fraction, in this two-phase coexistence, can take continuous infinity of values. All but one of these are metastable, and two-phase coexistence is not an equilibrium state.

  3. Thermophysical properties of coexistent phases of plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Freibert, Franz J [Los Alamos National Laboratory; Mitchell, Jeremy N [Los Alamos National Laboratory; Saleh, Tarik A [Los Alamos National Laboratory; Schwartz, Dan S [Los Alamos National Laboratory

    2009-01-01

    Plutonium is the element with the greatest number of allotropic phases. Thermally induced transformations between these phases are typically characterized by thermal hysteresis and incomplete phase reversion. With Ga substitutal in the lattice, low symmetry phases are replaced by a higher symmetry phase. However, the low temperature Martensitic phase transformation ({delta} {yields} {alpha}{prime}) in Ga stabilized {delta}-phase Pu is characterized by a region of thermal hysteresis which can reach 200 C in extent. These regions of thermal hysteresis offer a unique opportunity to study thermodynamics in inhomogeneous systems of coexistent phases. The results of thermophysical properties measured for samples of inhomogeneous unalloyed and Ga alloyed Pu will be discussed and compared with similar measurements of their single phase constituents.

  4. Thermophysical properties of coexistent phases of plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Freibert, F J; Mitchell, J N; Saleh, T A; Schwartz, D S, E-mail: freibert@lanl.gov, E-mail: jeremy@lanl.gov, E-mail: tsaleh@lanl.gov, E-mail: dschwartz@lanl.gov [Nuclear Materials Science Group, Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2010-03-15

    Plutonium is the element with the greatest number of allotropic phases. Thermally induced transformations between these phases are typically characterized by thermal hysteresis and incomplete phase reversion. With Ga substitutional in the lattice, low symmetry phases are replaced by a higher symmetry phase. However, the low temperature martensitic phase transformation ({delta}{yields}{alpha}') in Ga stabilized {delta}-phase Pu is characterized by a region of thermal hysteresis which can reach 200 deg. C in extent. These regions of thermal hysteresis offer a unique opportunity to study thermodynamics in inhomogeneous systems of coexistent phases. The results of thermophysical properties measured for samples of inhomogeneous unalloyed and Ga alloyed Pu will be discussed and compared with similar measurements of their single phase constituents.

  5. Limits on new forces coexisting with electromagnetism

    Energy Technology Data Exchange (ETDEWEB)

    Kloor, H.; Fischbach, E.; Talmadge, C. (Physics Department, Purdue University, West Lafayette, Indiana 47907 (United States)); Greene, G.L. (National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States))

    1994-02-15

    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 [lambda] extends from the subatomic scale ([lambda][approx]10[sup [minus]15] m) to the astrophysical scale ([lambda][approx]10[sup 12] m).

  6. Coexistence of rheumatoid arthritis and ankylosing spondylitis.

    Science.gov (United States)

    Barczyńska, Tacjana Anna; Węgierska, Małgorzata; Żuchowski, Paweł; Dura, Marta; Zalewska, Joanna; Waszczak, Marzena; Jeka, Sławomir

    2015-01-01

    Rheumatoid arthritis (RA) and ankylosing spondylitis (AS) are chronic progressive inflammatory diseases, leading to joint damage and reducing the physical fitness of patients. They are among the most common rheumatic diseases. However, their etiology and symptomatology are different. Formerly, AS was often wrongly diagnosed as RA. Today there are no major diagnostic difficulties in differentiation between these diseases, thanks to modern laboratory tests and imaging. However, a problem may arise when the patient has symptoms typical for both diseases simultaneously. Cases of coexistence of RA with AS - according to our best knowledge - are rare. This study aims to compare our experience in diagnosis and treatment of concomitant RA and AS with the experience of other researchers. Implementation of the proper diagnostic algorithm, allowing for correct diagnosis of both diseases in one patient, may be useful for differential diagnosis of similar cases in the future.

  7. Fixation-coexistence transition in spatial populations

    Science.gov (United States)

    Dall'Asta, Luca; Caccioli, Fabio; Beghè, Deborah

    2013-01-01

    Balancing selection is a special case of frequency-dependent selection that is known to be the major force for the maintenance of biodiversity and polymorphism in natural populations. In finite populations, genetic drift eventually drives the population to fixation to the detriment of biodiversity. The interplay between selection and genetic drift is much richer in spatially extended populations, where the local density of individuals can be low even in the limit of infinitely large systems. We consider the limit of low local density of individuals (strong genetic drift) that is well represented by a modified voter model. We show analytically the existence of a non-equilibrium phase transition between a region in which fixation always occurs and a coexistence phase for a one-dimensional system. We also provide a characterization of the dynamical properties of the system, in particular for what concerns the coarsening behavior and the speed of propagation of heterozygosity above the threshold.

  8. Shape coexistence: the shell model view

    Science.gov (United States)

    Poves, A.

    2016-02-01

    We shall discuss the meaning of the ‘nuclear shape’ in the laboratory frame proper to the spherical shell model. A brief historical promenade will bring us from Elliott’s SU3 breakthrough to today’s large scale shell model calculations. A section is devoted to the algebraic model which extends drastically the field of applicability of Elliot’s SU3, providing a precious heuristic guidance for the exploration of collectivity in the nuclear chart. Shape coexistence and shape mixing will be shown to occur as the result of the competition between the main actors in the nuclear dynamics; the spherical mean field, and the pairing and quadrupole-quadrupole interactions. These ideas will be illustrated with examples in magic nuclei (40Ca and 68Ni); neutron rich semi-magic (32Mg, and 64Cr); and in proton rich N = Z (72Kr).

  9. Competitive exclusion and coexistence of universal grammars.

    Science.gov (United States)

    Mitchener, W Garrett; Nowak, Martin A

    2003-01-01

    Universal grammar (UG) is a list of innate constraints that specify the set of grammars that can be learned by the child during primary language acquisition. UG of the human brain has been shaped by evolution. Evolution requires variation. Hence, we have to postulate and study variation of UG. We investigate evolutionary dynamics and language acquisition in the context of multiple UGs. We provide examples for competitive exclusion and stable coexistence of different UGs. More specific UGs admit fewer candidate grammars, and less specific UGs admit more candidate grammars. We will analyze conditions for more specific UGs to outcompete less specific UGs and vice versa. An interesting finding is that less specific UGs can resist invasion by more specific UGs if learning is more accurate. In other words, accurate learning stabilizes UGs that admit large numbers of candidate grammars.

  10. Novel trophic cascades: apex predators enable coexistence.

    Science.gov (United States)

    Wallach, Arian D; Ripple, William J; Carroll, Scott P

    2015-03-01

    Novel assemblages of native and introduced species characterize a growing proportion of ecosystems worldwide. Some introduced species have contributed to extinctions, even extinction waves, spurring widespread efforts to eradicate or control them. We propose that trophic cascade theory offers insights into why introduced species sometimes become harmful, but in other cases stably coexist with natives and offer net benefits. Large predators commonly limit populations of potentially irruptive prey and mesopredators, both native and introduced. This top-down force influences a wide range of ecosystem processes that often enhance biodiversity. We argue that many species, regardless of their origin or priors, are allies for the retention and restoration of biodiversity in top-down regulated ecosystems.

  11. Co-existence in multispecies biofilm communities

    DEFF Research Database (Denmark)

    Røder, Henriette Lyng

    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...... of member species increases. After this, various approaches taken by different studies when investigating multispecies communities are discussed, and different techniques for studying multispecies biofilm are described. In manuscript 2, a diverse group of bacteria was co-isolated from a meat processing...... the community. The increased biofilm biomass produced by the new wrinkled variant of X. retroflexus lead to a more positive or neutral co-existence with P. amylolyticus compared to the wild type X. retroflexus. Manuscript 6 investigated how a multispecies biofilm was affected from grazing by the heterotrophic...

  12. 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...

  13. 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.

  14. Flare Plasma Iron Abundance

    Science.gov (United States)

    Dennis, Brian R.; Dan, Chau; Jain, Rajmal; Schwartz, Richard A.; Tolbert, Anne K.

    2008-01-01

    The equivalent width of the iron-line complex at 6.7 keV seen in flare X-ray spectra suggests that the iron abundance of the hottest plasma at temperatures >approx.10 MK may sometimes be significantly lower than the nominal coronal abundance of four times the photospheric value that is commonly assumed. This conclusion is based on X-ray spectral observations of several flares seen in common with the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and the Solar X-ray Spectrometer (SOXS) on the second Indian geostationary satellite, GSAT-2. The implications of this will be discussed as it relates to the origin of the hot flare plasma - either plasma already in the corona that is directly heated during the flare energy release process or chromospheric plasma that is heated by flare-accelerated particles and driven up into the corona. Other possible explanations of lower-than-expected equivalent widths of the iron-line complex will also be discussed.

  15. Population expansions shared among coexisting bacterial lineages are revealed by genetic evidence.

    Science.gov (United States)

    Avitia, Morena; Escalante, Ana E; Rebollar, Eria A; Moreno-Letelier, Alejandra; Eguiarte, Luis E; Souza, Valeria

    2014-01-01

    Comparative population studies can help elucidate the influence of historical events upon current patterns of biodiversity among taxa that coexist in a given geographic area. In particular, comparative assessments derived from population genetics and coalescent theory have been used to investigate population dynamics of bacterial pathogens in order to understand disease epidemics. In contrast, and despite the ecological relevance of non-host associated and naturally occurring bacteria, there is little understanding of the processes determining their diversity. Here we analyzed the patterns of genetic diversity in coexisting populations of three genera of bacteria (Bacillus, Exiguobacterium, and Pseudomonas) that are abundant in the aquatic systems of the Cuatro Cienegas Basin, Mexico. We tested the hypothesis that a common habitat leaves a signature upon the genetic variation present in bacterial populations, independent of phylogenetic relationships. We used multilocus markers to assess genetic diversity and (1) performed comparative phylogenetic analyses, (2) described the genetic structure of bacterial populations, (3) calculated descriptive parameters of genetic diversity, (4) performed neutrality tests, and (5) conducted coalescent-based historical reconstructions. Our results show a trend of synchronic expansions across most populations independent of both lineage and sampling site. Thus, we provide empirical evidence supporting the analysis of coexisting bacterial lineages in natural environments to advance our understanding of bacterial evolution beyond medical or health-related microbes.

  16. Ultrasonic features of papillary thyroid microcarcinoma coexisting with a thyroid abnormality

    Science.gov (United States)

    Li, Bo; Zhang, Yaqiong; Yin, Ping; Zhou, Jian; Jiang, Tian'an

    2016-01-01

    The present study aimed to investigate the value of ultrasonography in the diagnosis of papillary thyroid microcarcinoma (PTMC) coexisting with a thyroid abnormality, and to improve the accuracy of PTMC diagnosis. The ultrasonic features of 38 PTMC nodules coexisting with a thyroid abnormality and 56 thyroid benign nodules, obtained by surgical resection and confirmed by pathological analysis, were retrospectively analyzed. All masses were ≤ 1.0 cm in diameter. Ultrasonic features that were analyzed included the shape, aspect ratio, boundary, margin, echo, uniformity, presence or absence of microcalcification and enlargement of the lymph nodes, as well as the blood flow of the nodules. Furthermore, the sensitivity, specificity and accuracy of ultrasonography for the diagnosis of PTMC were obtained. The following ultrasonic features of thyroid nodules were significantly (Phypoechogenicity; and microcalcification. Therefore, thyroid nodules with these ultrasonic characteristics coexisting with a thyroid abnormality may be suspected as malignant PTMC. The present study demonstrated that ultrasound-guided biopsies are necessary to prevent misdiagnosis of PTMC. The sensitivities of enlarged neck lymph nodes and abundant blood flow are so low that they may be considered as references for the differentiation of PTMC from benign nodules. PMID:27698812

  17. Cisplatin induces tolerogenic dendritic cells in response to TLR agonists via the abundant production of IL-10, thereby promoting Th2- and Tr1-biased T-cell immunity

    Science.gov (United States)

    Kim, Hongmin; Kwon, Kee Woong; Im, Sin-Hyeog; Lee, Bo Ryeong; Ha, Sang-Jun; Shin, Sung Jae

    2016-01-01

    Although many advantageous roles of cisplatin (cis-diamminedichloroplatinum (II), CDDP) have been reported in cancer therapy, the immunomodulatory roles of cisplatin in the phenotypic and functional alterations of dendritic cells (DCs) are poorly understood. Here, we investigated the effect of cisplatin on the functionality of DCs and the changes in signaling pathways activated upon toll-like receptor (TLR) stimulation. Cisplatin-treated DCs down-regulated the expression of cell surface molecules (CD80, CD86, MHC class I and II) and up-regulated endocytic capacity in a dose-dependent manner. Upon stimulation with various TLR agonists, cisplatin-treated DCs showed markedly increased IL-10 production through activation of the p38 MAPK and NF-κB signaling pathways without altering the levels of TNF-α and IL-12p70, indicating the cisplatin-mediated induction of tolerogenic DCs. This effect was dependent on the production of IL-10 from DCs, as neither DCs isolated from IL-10−/− mice nor IL-10-neutralized DCs generated tolerogenic DCs. Interestingly, DCs that were co-treated with cisplatin and lipopolysaccharide (LPS) exhibited a decreased immunostimulatory capacity for inducing the proliferation of Th1- and Th17-type T cells; instead, these DCs contributed to Th2-type T cell immunity. Furthermore, in vitro and in vivo investigations revealed a unique T cell population, IL-10-producing CD3+CD4+LAG-3+CD49b+CD25−Foxp3− Tr1 cells, that was significantly increased without altering the Foxp3+ regulatory T cell population. Taken together, our results suggest that cisplatin induces immune-suppressive tolerogenic DCs in TLR agonist-induced inflammatory conditions via abundant IL-10 production, thereby skewing Th cell differentiation towards Th2 and Tr1 cells. This relationship may provide cancer cells with an opportunity to evade the immune system. PMID:27172902

  18. CT imaging of coexisting pulmonary tuberculosis and lung cancer

    Institute of Scientific and Technical Information of China (English)

    吕岩

    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

  19. 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

    In the European Union, freedom of choice between genetically modified (GM) and conventional or organic crops, for both producers and consumers, should be provided through coexistence measures. Coexistence measures at the farm level differ in costs and effectiveness and should not tip the balance ...

  20. Double Jeopardy for Children Who Stutter: Race and Coexisting Disorders

    Science.gov (United States)

    Blood, Gordon W.; Blood, Ingrid; Kreiger, Jennifer; O'Connor, Shelah; Qualls, Constance Dean

    2009-01-01

    The primary purpose of this study was to examine the influence of racial and ethnic backgrounds in children who stutter (CWS) with 18 specific coexisting disorders. A sample of 1,184 speech-language pathologists responded to a detailed questionnaire designed to answer questions about the type and prevalence of coexisting disorders in 2,535 CWS.…

  1. 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. rasch...

  2. Abundance, Excess, Waste

    Directory of Open Access Journals (Sweden)

    Rox De Luca

    2016-02-01

    Her recent work focuses on the concepts of abundance, excess and waste. These concerns translate directly into vibrant and colourful garlands that she constructs from discarded plastics collected on Bondi Beach where she lives. The process of collecting is fastidious, as is the process of sorting and grading the plastics by colour and size. This initial gathering and sorting process is followed by threading the components onto strings of wire. When completed, these assemblages stand in stark contrast to the ease of disposability associated with the materials that arrive on the shoreline as evidence of our collective human neglect and destruction of the environment around us. The contrast is heightened by the fact that the constructed garlands embody the paradoxical beauty of our plastic waste byproducts, while also evoking the ways by which those byproducts similarly accumulate in randomly assorted patterns across the oceans and beaches of the planet.

  3. Living with lions: the economics of coexistence in the Gir forests, India.

    Directory of Open Access Journals (Sweden)

    Kausik Banerjee

    Full Text Available Rarely human communities coexist in harmony with large predators. Most often communities suffer due to predation on their stock while large carnivores suffer losses and at times extirpation due to retaliation. We examine the mechanisms permitting the coexistence of Asiatic lions (Panthera leo persica and pastoral communities (Maldharis in the Gir forests, India. We monitored six Maldhari settlements between 2005 and 2007 to quantify seasonal livestock holding, density and losses due to predation and other causes. Lion density, estimated by mark recapture, was 15±0.1 SE/100 km(2. Livestock density, estimated by total counts, ranged between 25/km(2-31/km(2 with buffaloes being most abundant. Average livestock holding of Maldhari families was 33±3 SE. Lions predated mostly on unproductive cattle (30%. Scat analysis (n = 165, predation events (n = 180 and seven continuous monitoring sessions of 1,798 hours on four radio-collared lions estimated livestock to contribute between 25 to 42% of lions' biomass consumptions, of which only 16% was predated; rest scavenged. With free grazing rights within Gir forests, Maldharis offset 58±0.2 SE% of annual livestock rearing cost in comparison to non-forest dwelling pastoralists. With government compensation scheme for livestock predation, this profit margin augmented to 76±0.05 SE%. Lion density was higher in areas with Maldhari livestock in comparison to areas without livestock. Thus, the current lifestyles and livestock holdings of Maldharis seem to be beneficial to both lions and local pastoralists. We conclude that a combination of strict protection regime for lions, Maldharis' traditional reverence towards lions and the livelihood economics permit the delicate balance of lion-Maldhari coexistence. Indefinite increase in human and livestock population within Gir might upset this equilibrium undermining the conservation objectives. We see no end to compensation programs worldwide as they constitute a

  4. Living with lions: the economics of coexistence in the Gir forests, India.

    Science.gov (United States)

    Banerjee, Kausik; Jhala, Yadvendradev V; Chauhan, Kartikeya S; Dave, Chittranjan V

    2013-01-01

    Rarely human communities coexist in harmony with large predators. Most often communities suffer due to predation on their stock while large carnivores suffer losses and at times extirpation due to retaliation. We examine the mechanisms permitting the coexistence of Asiatic lions (Panthera leo persica) and pastoral communities (Maldharis) in the Gir forests, India. We monitored six Maldhari settlements between 2005 and 2007 to quantify seasonal livestock holding, density and losses due to predation and other causes. Lion density, estimated by mark recapture, was 15±0.1 SE/100 km(2). Livestock density, estimated by total counts, ranged between 25/km(2)-31/km(2) with buffaloes being most abundant. Average livestock holding of Maldhari families was 33±3 SE. Lions predated mostly on unproductive cattle (30%). Scat analysis (n = 165), predation events (n = 180) and seven continuous monitoring sessions of 1,798 hours on four radio-collared lions estimated livestock to contribute between 25 to 42% of lions' biomass consumptions, of which only 16% was predated; rest scavenged. With free grazing rights within Gir forests, Maldharis offset 58±0.2 SE% of annual livestock rearing cost in comparison to non-forest dwelling pastoralists. With government compensation scheme for livestock predation, this profit margin augmented to 76±0.05 SE%. Lion density was higher in areas with Maldhari livestock in comparison to areas without livestock. Thus, the current lifestyles and livestock holdings of Maldharis seem to be beneficial to both lions and local pastoralists. We conclude that a combination of strict protection regime for lions, Maldharis' traditional reverence towards lions and the livelihood economics permit the delicate balance of lion-Maldhari coexistence. Indefinite increase in human and livestock population within Gir might upset this equilibrium undermining the conservation objectives. We see no end to compensation programs worldwide as they constitute a crucial

  5. A simple rule of direct reciprocity leads to the stable coexistence of cooperation and defection in the Prisoner's Dilemma game.

    Science.gov (United States)

    Zheng, Xiu-Deng; Li, Cong; Yu, Jie-Ru; Wang, Shi-Chang; Fan, Song-Jia; Zhang, Bo-Yu; Tao, Yi

    2017-03-01

    The long-term coexistence of cooperation and defection is a common phenomenon in nature and human society. However, none of the theoretical models based on the Prisoner's Dilemma (PD) game can provide a concise theoretical model to explain what leads to the stable coexistence of cooperation and defection in the long-term even though some rules for promoting cooperation have been summarized (Nowak, 2006, Science 314, 1560-1563). Here, based on the concept of direct reciprocity, we develop an elementary model to show why stable coexistence of cooperation and defection in the PD game is possible. The basic idea behind our theoretical model is that all players in a PD game prefer a cooperator as an opponent, and our results show that considering strategies allowing opting out against defection provide a general and concise way of understanding the fundamental importance of direct reciprocity in driving the evolution of cooperation.

  6. Widespread Attenuation of Antibiotics by Soil Bacteria Promotes Intermixed Microbial Diversity

    Science.gov (United States)

    Vetsigin, Kalin; Kelsic, Eric; Zhao, Jeffrey; Kishony, Roy

    2014-03-01

    In natural soil environments, antibiotic sensitive bacteria coexist with antibiotic producers, even in close proximities. Efforts to understand diversity in microbial communities have focused on pairwise interactions between species, yet mathematical models of such interactions lead to distinct spatial domains of individual species, rather than to intermixed multi-species communities. In this work, we measured interactions between triplets of species and asked and how the presence of these higher-order interactions affects community structure and diversity. We developed a 3-species diffusion-based assay in which a modulator species either intensifies or attenuates the toxicity of compounds made by a producer species against a fluorescently labeled indicator species. We found that intensifying interactions were quite rare among soil bacteria, while attenuating interactions that protected nearby sensitive species from the antibiotic producer were abundant. Furthermore, many soil bacteria attenuated multiple classes of antibiotics with widely varying mechanisms of action. Computer simulations showed that such cross-species protection, when abundant, promoted the spontaneous formation and expansion of intermixed multi-species communities that overtook or assimilated single species domains. These findings suggest that drug attenuation is a widespread phenomenon that can be key to the coexistence of antibiotic producing and sensitive microbes in close proximity and thereby to the overall species diversity within soil microenvironments.

  7. Estimating the probability of coexistence in cross-feeding communities.

    Science.gov (United States)

    Vessman, Björn; Gerlee, Philip; Lundh, Torbjörn

    2016-11-07

    The dynamics of many microbial ecosystems are driven by cross-feeding interactions, in which metabolites excreted by some species are metabolised further by others. The population dynamics of such ecosystems are governed by frequency-dependent selection, which allows for stable coexistence of two or more species. We have analysed a model of cross-feeding based on the replicator equation, with the aim of establishing criteria for coexistence in ecosystems containing three species, given the information of the three species' ability to coexist in their three separate pairs, i.e. the long term dynamics in the three two-species component systems. The triple-system is studied statistically and the probability of coexistence in the species triplet is computed for two models of species interactions. The interaction parameters are modelled either as stochastically independent or organised in a hierarchy where any derived metabolite carries less energy than previous nutrients in the metabolic chain. We differentiate between different modes of coexistence with respect to the pair-wise dynamics of the species, and find that the probability of coexistence is close to 12 for triplet systems with three pair-wise coexistent pairs and for the so-called intransitive systems. Systems with two and one pair-wise coexistent pairs are more likely to exist for random interaction parameters, but are on the other hand much less likely to exhibit triplet coexistence. Hence we conclude that certain species triplets are, from a statistical point of view, rare, but if allowed to interact are likely to coexist. This knowledge might be helpful when constructing synthetic microbial communities for industrial purposes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  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. Coexistence of two sympatric and mOrpho1ogically similar bat species Rhinolophus affnis and Rhinolophus pearsoni

    Institute of Scientific and Technical Information of China (English)

    Tinglei Jiang; Jiang Feng; Keping Sun; Jing Wang

    2008-01-01

    Ecologists have long focused on the coexistence of sympatric species.Here,we investigated two horseshoe bat species,Rhinolophus affinis and Rhinolophus pearsoni inhabited in the same cave,for their foraging strategies,niche differentiation,prey selection,and their coexistence status.These two species of horseshoe bats were ditierent in the dominant frequency of their echolocation calls.but similar in their morphology.We found evidence for prey selectivity although there was a high degree of overlap in prey categories and sizes.R affinis and R pearsoni foraged on 16 and 7 categories insects,respectively,with Pyralidae,Geometridae,Melolonthidae dominating their diets.The degree of trophic niche overlap was 0.69.Pairwise comparisons suggested that there was no obvious differentiation in prey categories and size.However,high prey availability in the environment(Simpson diversity index=0.79 and Margalef richness index=4.121 contributed to their coexistence by dampening the interspecific competition.Since there are one or more mechanisms facilitating species coexistence in a community,our results suggest that the spatial niche differentiation in foraging microhabitats and in foraging habitats at landscape scale may promote the coexistence of the two bat species.However,additional field data are needed to confirm this speculation.

  10. Primordial Deuterium Abundance Measurements

    CERN Document Server

    Levshakov, S A; Takahara, F; Levshakov, Sergei A.; Kegel, Wilhelm H.; Takahara, Fumio

    1997-01-01

    Deuterium abundances measured recently from QSO absorption-line systems lie in the range from 3 10^{-5} to 3 10^{-4}, which shed some questions on standard big bang theory. We show that this discordance may simply be an artifact caused by inadequate analysis ignoring spatial correlations in the velocity field in turbulent media. The generalized procedure (accounting for such correlations) is suggested to reconcile the D/H measurements. An example is presented based on two high-resolution observations of Q1009+2956 (low D/H) [1,2] and Q1718+4807 (high D/H) [8,9]. We show that both observations are compatible with D/H = 4.1 - 4.6 10^{-5}, and thus support SBBN. The estimated mean value = 4.4 10^{-5} corresponds to the baryon-to-photon ratio during SBBN eta = 4.4 10^{-10} which yields the present-day baryon density Omega_b h^2 = 0.015.

  11. Coexistence of competitors mediated by nonlinear noise

    Science.gov (United States)

    Siekmann, Ivo; Bengfort, Michael; Malchow, Horst

    2017-06-01

    Stochastic reaction-diffusion equations are a popular modelling approach for studying interacting populations in a heterogeneous environment under the influence of environmental fluctuations. Although the theoretical basis of alternative models such as Fokker-Planck diffusion is not less convincing, movement of populations is most commonly modelled using the diffusion law due to Fick. An interesting feature of Fokker-Planck diffusion is the fact that for spatially varying diffusion coefficients the stationary solution is not a homogeneous distribution - in contrast to Fick's law of diffusion. Instead, concentration accumulates in regions of low diffusivity and tends to lower levels for areas of high diffusivity. Thus, we may interpret the stationary distribution of the Fokker-Planck diffusion as a reflection of different levels of habitat quality. Moreover, the most common model for environmental fluctuations, linear multiplicative noise, is based on the assumption that individuals respond independently to stochastic environmental fluctuations. For large population densities the assumption of independence is debatable and the model further implies that noise intensities can increase to arbitrarily high levels. Therefore, instead of the commonly used linear multiplicative noise model, we implement environmental variability by an alternative nonlinear noise term which never exceeds a certain maximum noise intensity. With Fokker-Planck diffusion and the nonlinear noise model replacing the classical approaches we investigate a simple invasive system based on the Lotka-Volterra competition model. We observe that the heterogeneous stationary distribution generated by Fokker-Planck diffusion generally facilitates the formation of segregated habitats of resident and invader. However, this segregation can be broken by nonlinear noise leading to coexistence of resident and invader across the whole spatial domain, an effect that would not be possible in the non

  12. The Effects of Dynamical Rates on Species Coexistence in a Variable Environment: The Paradox of the Plankton Revisited.

    Science.gov (United States)

    Li, Lina; Chesson, Peter

    2016-08-01

    Hutchinson's famous hypothesis for the "paradox of the plankton" has been widely accepted, but critical aspects have remained unchallenged. Hutchinson argued that environmental fluctuations would promote coexistence when the timescale for environmental change is comparable to the timescale for competitive exclusion. Using a consumer-resource model, we do find that timescales of processes are important. However, it is not the time to exclusion that must be compared with the time for environmental change but the time for resource depletion. Fast resource depletion, when resource consumption is favored for different species at different times, strongly promotes coexistence. The time for exclusion is independent of the rate of resource depletion. Therefore, the widely believed predictions of Hutchinson are misleading. Fast resource depletion, as determined by environmental conditions, ensures strong coupling of environmental processes and competition, which leads to enhancement over time of intraspecific competition relative to interspecific competition as environmental shifts favor different species at different times. This critical coupling is measured by the covariance between environment and competition. Changes in this quantity as densities change determine the stability of coexistence and provide the key to rigorous analysis, both theoretically and empirically, of coexistence in a variable environment. These ideas apply broadly to diversity maintenance in variable environments whether the issue is species diversity or genetic diversity and competition or apparent competition.

  13. Metabolic Trade-Offs Promote Diversity in a Model Ecosystem

    Science.gov (United States)

    Posfai, Anna; Taillefumier, Thibaud; Wingreen, Ned S.

    2017-01-01

    In nature, a large number of species can coexist on a small number of shared resources; however, resource-competition models predict that the number of species in steady coexistence cannot exceed the number of resources. Motivated by recent studies of phytoplankton, we introduce trade-offs into a resource-competition model and find that an unlimited number of species can coexist. Our model spontaneously reproduces several notable features of natural ecosystems, including keystone species and population dynamics and abundances characteristic of neutral theory, despite an underlying non-neutral competition for resources.

  14. COEXISTING PERIODIC ORBITS IN VIBRO-IMPACTING DYNAMICAL SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    李群宏; 陆启韶

    2003-01-01

    A method is presented to seek for coexisting periodic orbits which may be stable or unstable in piecewise-linear vibro-impacting systems. The conditions for coexistence of single impact periodic orbits are derived, and in particular, it is investigated in details how to assure that no other impacts will happen in an evolution period of a single impact periodic motion. Furthermore, some criteria for nonexistence of single impact periodic orbits with specific periods are also established. Finally, the stability of coexisting periodic orbits is discussed, and the corresponding computation formula is given. Examples of numerical simulation are in good agreement with the theoretic analysis.

  15. The Curious Case of the Camelthorn: Competition, Coexistence, and Nest-Site Limitation in a Multispecies Mutualism.

    Science.gov (United States)

    Campbell, Heather; Fellowes, Mark D E; Cook, James M

    2015-12-01

    Myrmecophyte plants house ants within domatia in exchange for protection against herbivores. Ant-myrmecophyte mutualisms exhibit two general patterns due to competition between ants for plant occupancy: (i) domatia nest sites are a limiting resource and (ii) each individual plant hosts one ant species at a time. However, individual camelthorn trees (Vachellia erioloba) typically host two to four ant species simultaneously, often coexisting in adjacent domatia on the same branch. Such fine-grain spatial coexistence brings into question the conventional wisdom on ant-myrmecophyte mutualisms. Camelthorn ants appear not to be nest-site limited, despite low abundance of suitable domatia, and have random distributions of nest sites within and across trees. These patterns suggest a lack of competition between ants for domatia and contrast strongly with other ant-myrmecophyte systems. Comparison of this unusual case with others suggests that spatial scale is crucial to coexistence or competitive exclusion involving multiple ant species. Furthermore, coexistence may be facilitated when co-occurring ant species diverge strongly on at least one niche axis. Our conclusions provide recommendations for future ant-myrmecophyte research, particularly in utilizing multispecies systems to further our understanding of mutualism biology.

  16. The Role of Within-Host Competition for Coexistence in Multiparasitoid-Host Systems.

    Science.gov (United States)

    van Velzen, Ellen; Pérez-Vila, Saleta; Etienne, Rampal S

    2016-01-01

    Multiparasitism (females of multiple species parasitizing the same host) is a ubiquitous phenomenon in parasitoids, yet the role of within-host competition has been mostly ignored in multiparasitoid-host models. Here we study the effect of varying the degree of competition at different life stages: competition over oviposition sites (between-adult competition) and larval competition over resources within the host (within-host competition). We adapt a Nicholson-Bailey model to allow for varying levels of between-adult competition (varying the overlap in species distributions) and within-host competition (varying the number of offspring that can successfully emerge from a host). Surprisingly, while stronger between-adult competition reduces coexistence, stronger within-host competition promotes it. Asymmetric between-adult competition (a fecundity difference between the two species) reduces coexistence when compared to symmetric competition; this can be counteracted by asymmetric within-host competition (within-host competitive advantage of the lower-fecundity species), but only when within-host competition is strong and the correlation between the parasitoids' distributions is intermediate. We discuss our results in the context of the interaction between two parasitoid species, Nasonia vitripennis and Nasonia giraulti, which have strongly correlated distributions and high levels of multiparasitism in the field. We conclude that either low or asymmetric within-host competition is unlikely to explain their coexistence.

  17. Dynamics of nitrogen nutrition of coexisting dominant trees in mixed broad-leaved/Korean pine forest

    Institute of Scientific and Technical Information of China (English)

    Li Yuwen

    1999-01-01

    Chemical analysis of ammonium, nitrate and total nitrogen in tree leaves and roots and an in-vivo bioassay for nitrate reductase activity (NRA) were used to monitor the seasonal variations in nitrogen assimilation among four coexisting dominant tree species, including Pinus koraiensis, Ti/ia amurensis, Fraxinus mandshurica and Acer mono, in a virgin mixed broad-leaved/Korean pine (Pinus koraiensis) forest. The soil study included individual horizons of L+F (0-5 cm), Ah (5-11 cm) and Aw (11-25 cm). All four species had nitrate and ammonium in their roots and leaves, and also NRA in leaves. This indicated that these coexisting species were adapted to ammonium + nitrate nutrition. A negative correlation existed between nitrate use and ammonium use. Ammonium concentration was higher than that of nitrate in tree leaves and roots, and also in soils, which indicated climax woody species had a relative preference for ammonium nutrition. There was a positive relationship between tree nitrogen nutrition use and soil nitrogen nutrient supply. Utilization of ammonium and nitrate as well as the seasonal patterns differed significantly between the species. Peaks of ammonium, nitrate, NRA and total nitrogen in one species were therefore not necessarily synchronous with peaks in other species, and which indicated a species-specific seasonal use of nitrogen. The species-specific temporal differentiation in nitrogen use might reduce the competition between co-existing species and may be an important mechanism promoting stability of virgin mixed broad-leaved∥Korean pine forest.

  18. Prevalence, awareness, treatment and control of coexistence of diabetes and hypertension in thai population.

    Science.gov (United States)

    Tiptaradol, Siriwat; Aekplakorn, Wichai

    2012-01-01

    Diabetes and hypertension are major independent risk factors for cardiovascular and renal diseases; however, prevalence and characteristics of the coexistence in general population is not clear. Data from Thai National Health Examination Survey III were used to estimate the prevalence of coexistence of diabetes and hypertension, and to estimate the proportion of awareness, treatment and control of both conditions. A total of 36,877 (male 17,614 and female 19,263) participants were included in the study. The prevalence of people with diabetes and hypertension was 3.2% (male 2.8% and female 3.6%). Approximately half of the diabetes patients (49.0%, 95%CI 45.6, 52.5) had hypertension, and 14.4% (95%CI 13.0, 16.0) of hypertensive patients had diabetes. After controlling for covariates, factors associated with coexistence of diabetes and hypertension included; age ≥60 years (adjust odds ratio 1.38, 95%CI 1.14, 1.73), having education less than 6 years (1.83, 95%CI 1.03, 3.38) and abdominal obesity (2.49, 95%CI 2.00, 3.10). More than 80% were unaware of having both conditions. Target for control of both glucose and blood pressure among those treated was achieved in only 6.2%. In conclusion, patients with diabetes or hypertension should be promoted to have weight control and screening for the comorbidity.

  19. Prevalence, Awareness, Treatment and Control of Coexistence of Diabetes and Hypertension in Thai Population

    Directory of Open Access Journals (Sweden)

    Siriwat Tiptaradol

    2012-01-01

    Full Text Available Diabetes and hypertension are major independent risk factors for cardiovascular and renal diseases; however, prevalence and characteristics of the coexistence in general population is not clear. Data from Thai National Health Examination Survey III were used to estimate the prevalence of coexistence of diabetes and hypertension, and to estimate the proportion of awareness, treatment and control of both conditions. A total of 36,877 (male 17,614 and female 19,263 participants were included in the study. The prevalence of people with diabetes and hypertension was 3.2% (male 2.8% and female 3.6%. Approximately half of the diabetes patients (49.0%, 95%CI 45.6, 52.5 had hypertension, and 14.4% (95%CI 13.0, 16.0 of hypertensive patients had diabetes. After controlling for covariates, factors associated with coexistence of diabetes and hypertension included; age ≥60 years (adjust odds ratio 1.38, 95%CI 1.14, 1.73, having education less than 6 years (1.83, 95%CI 1.03, 3.38 and abdominal obesity (2.49, 95%CI 2.00, 3.10. More than 80% were unaware of having both conditions. Target for control of both glucose and blood pressure among those treated was achieved in only 6.2%. In conclusion, patients with diabetes or hypertension should be promoted to have weight control and screening for the comorbidity.

  20. The primordial helium abundance from updated emissivities

    CERN Document Server

    Aver, Erik; Porter, R L; Skillman, Evan D

    2013-01-01

    Observations of metal-poor extragalactic H II regions allow the determination of the primordial helium abundance, Y_p. The He I emissivities are the foundation of the model of the H II region's emission. Porter, Ferland, Storey, & Detisch (2012) have recently published updated He I emissivities based on improved photoionization cross-sections. We incorporate these new atomic data and update our recent Markov Chain Monte Carlo analysis of the dataset published by Izotov, Thuan, & Stasinska (2007). As before, cuts are made to promote quality and reliability, and only solutions which fit the data within 95% confidence level are used to determine the primordial He abundance. The previously qualifying dataset is almost entirely retained and with strong concordance between the physical parameters. Overall, an upward bias from the new emissivities leads to a decrease in Y_p. In addition, we find a general trend to larger uncertainties in individual objects (due to changes in the emissivities) and an increase...

  1. Ethnic Struggle, Coexistence, and Democratization in Eastern Europe

    OpenAIRE

    Cianetti, Licia

    2013-01-01

    Ethnic Struggle, Coexistence, and Democratization in Eastern Europe. By Sherrill Stroschein. Pp. 289. Cambridge: Cambridge University Press. 2012. £60.00. Hardback. ISBN: 9781107005242. Click here to read the review

  2. Coexistent adenocarcinoma and microcystic adenoma of the pancreas.

    Science.gov (United States)

    Posniak, H V; Olson, M C; Demos, T C

    1991-01-01

    A case with coexistent pancreatic adenocarcinoma and microcystic adenoma is presented. These diagnoses were suspected on the basis of their computed tomography (CT) appearances and confirmed with CT-guided fine-needle aspiration.

  3. Uterine didelphys coexisting with term pregnancy, an incidental ...

    African Journals Online (AJOL)

    Uterine didelphys coexisting with term pregnancy, an incidental finding during an ... AFRICAN JOURNALS ONLINE (AJOL) · Journals · Advanced Search ... carry their pregnancies to term with live deliveries without any complication, some ...

  4. Coexistence of pulmonary tuberculosis and sarcoidosis: a diagnostic dilemma.

    Science.gov (United States)

    Mandal, Sanjay Kumar; Ghosh, Sudip; Mondal, Soumya Sarathi; Chatterjee, Sumanta

    2014-12-19

    Tuberculosis and sarcoidosis are multisystem diseases having different aetiology and management; however, they have similar clinical and histological characteristics. Very rarely they may coexist. We report a rare case of a 38-year-old woman who presented with chronic cough, low-grade fever and respiratory distress that was initially diagnosed as miliary tuberculosis. Diagnosis was supported by positive mycobacterial culture and initially responded to antitubercular treatment, but later recurrences led to further investigations and the diagnosis of coexisting sarcoidosis.

  5. Antibiotics promote aggregation within aquatic bacterial communities

    Directory of Open Access Journals (Sweden)

    Gianluca eCorno

    2014-07-01

    Full Text Available The release of antibiotics (AB into the environment poses several threats for human health due to potential development of ABresistant natural bacteria. Even though the use of low-dose antibiotics has been promoted in health care and farming, significant amounts of AB are observed in aquatic environments. Knowledge on the impact of AB on natural bacterial communities is missing both in terms of spread and evolution of resistance mechanisms, and of modifications of community composition and productivity. New approaches are required to study the response of microbial communities rather than individual resistance genes. In this study a chemostat-based experiment with 4 coexisting bacterial strains has been performed to mimicking the response of a freshwater bacterial community to the presence of antibiotics in low and high doses. Bacterial abundance rapidly decreased by 75% in the presence of AB, independently of their concentration, and remained constant until the end of the experiment. The bacterial community was mainly dominated by Aeromonas hydrophila and Brevundimonas intermedia while the other two strains, Micrococcus luteus and Rhodococcus sp. never exceed 10%. Interestingly, the bacterial strains, which were isolated at the end of the experiment, were not AB-resistant, while reassembled communities composed of the 4 strains, isolated from treatments under AB stress, significantly raised their performance (growth rate, abundance in the presence of AB compared to the communities reassembled with strains isolated from the treatment without AB. By investigating the phenotypic adaptations of the communities subjected to the different treatments, we found that the presence of AB significantly increased co-aggregation by 5-6 fold.These results represent the first observation of co-aggregation as a successful strategy of AB resistance based on phenotype in aquatic bacterial communities, and can represent a fundamental step in the understanding of

  6. The dietary basis for temporal partitioning: food habits of coexisting Acomys species.

    Science.gov (United States)

    Kronfeld-Schor, Noga; Dayan, Tamar

    1999-10-01

    Two rodent species of the genus Acomys coexist on rocky terrain in the southern deserts of Israel. The common spiny mouse (A. cahirinus) is nocturnally active whereas the golden spiny mouse (A. russatus) is diurnally active. An early removal study suggested that competition accounts for this pattern of temporal partitioning: the golden spiny mouse is forced into diurnal activity by its congener. Theoretically, temporal segregation should facilitate coexistence if the shared limiting resources differ at different times (primarily among predators whose prey populations have activity rhythms), or if they are renewed within the period of the temporal segregation. We studied food preferences of the two Acomys species in a controlled cafeteria experiment in order to assess resource overlap and the potential for competition for food between the two species. We found no significant difference in food preferences between species. The dietary items preferred by both were arthropods. We also carried out a seasonal study of the percentage and identity of arthropods taken in the field by individuals of the two species. Individuals of both species took on annual average a high percentage of arthropods in their diets. Seasonal diet shifts reflect seasonal abundance of arthropods at Ein Gedi during day and night. Diurnal activity may also reduce interspecific interference competition between A. russatus and A. cahirinus. However, the strong interspecific dietary overlap in food preference, the heavy reliance on arthropods in spiny mouse diets, and the seasonal and circadian differences in arthropod consumption suggest that prey partitioning may be a viable mechanism of coexistence in this system.

  7. 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.

  8. Coexistence of Lactic Acid Bacteria and Potential Spoilage Microbiota in a Dairy Processing Environment.

    Science.gov (United States)

    Stellato, Giuseppina; De Filippis, Francesca; La Storia, Antonietta; Ercolini, Danilo

    2015-11-01

    Microbial contamination in food processing plants can play a fundamental role in food quality and safety. In this study, the microbiota in a dairy plant was studied by both 16S rRNA- and 26S rRNA-based culture-independent high-throughput amplicon sequencing. Environmental samples from surfaces and tools were studied along with the different types of cheese produced in the same plant. The microbiota of environmental swabs was very complex, including more than 200 operational taxonomic units with extremely variable relative abundances (0.01 to 99%) depending on the species and sample. A core microbiota shared by 70% of the samples indicated a coexistence of lactic acid bacteria with a remarkable level of Streptococcus thermophilus and possible spoilage-associated bacteria, including Pseudomonas, Acinetobacter, and Psychrobacter, with a relative abundance above 50%. The most abundant yeasts were Kluyveromyces marxianus, Yamadazyma triangularis, Trichosporon faecale, and Debaryomyces hansenii. Beta-diversity analyses showed a clear separation of environmental and cheese samples based on both yeast and bacterial community structure. In addition, predicted metagenomes also indicated differential distribution of metabolic pathways between the two categories of samples. Cooccurrence and coexclusion pattern analyses indicated that the occurrence of potential spoilers was excluded by lactic acid bacteria. In addition, their persistence in the environment can be helpful to counter the development of potential spoilers that may contaminate the cheeses, with possible negative effects on their microbiological quality.

  9. Co-culturing Effects of Coexisting Bacteria on Wood Degradation by Trametes versicolor.

    Science.gov (United States)

    Kamei, Ichiro

    2017-01-01

    White-rot fungi are the main decomposers of wood cell-wall polymer in forest ecosystems. Little is known, however, about the interactions between white-rot fungi and other coexisting microorganisms in decayed wood. A white-rot fungus, Trametes versicolor strain TN6F, was isolated from a fruit body, and 44 strains of coexisting cultivable bacteria were isolated from its substrate, natural white rot-decayed wood. The effects of these bacteria on fungal growth were examined by an in vitro confrontation growth assay. Among the isolates, nine bacterial strains inhibited the growth of strain TN6F, while 35 strains did not affect the growth of TN6F. However, when co-cultured with strain TN6F on wood powder, many bacterial strains promoted the weight loss of the substrate. A subsequent chemical composition analysis showed that co-culturing accelerated delignification. Higher laccase activity was detected when strain TN6F was co-cultured on wood powder medium with bacterial strains TN6W-26 or TN6W-27. These results indicate that some bacterial strains might promote wood degradation.

  10. Human-carnivore coexistence on communal land bordering the greater Kruger area, South Africa.

    Science.gov (United States)

    Lagendijk, D D Georgette; Gusset, Markus

    2008-12-01

    The aim of this study was to assess the potential for coexistence between rural people (living adjacent to a protected area) and predators (from the same area) ranging onto communal land. Ninety members of local communities bordering Manyeleti Game Reserve, which is contiguous with Kruger National Park, South Africa were interviewed. Respondents expressed diverging attitudes toward predators, which were more favorable among participants with higher education. Negative views were particularly due to fear of human and livestock losses, especially to lions, Panthera leo. Lions were thought to be the most abundant predator both within and outside the reserve. Lions were also the best known predator and were most often held responsible for killing livestock. Despite these livestock losses and a lack of conservation education, most participants voiced favorable opinions about large carnivore conservation, as predators were considered an integral part of the respondents' natural heritage. Thanks to this cultural tolerance and also because of a largely accepted management policy regarding predator control, large carnivores and people can coexist in the vicinity of Kruger National Park.

  11. Human Carnivore Coexistence on Communal Land Bordering the Greater Kruger Area, South Africa

    Science.gov (United States)

    Lagendijk, D. D. Georgette; Gusset, Markus

    2008-12-01

    The aim of this study was to assess the potential for coexistence between rural people (living adjacent to a protected area) and predators (from the same area) ranging onto communal land. Ninety members of local communities bordering Manyeleti Game Reserve, which is contiguous with Kruger National Park, South Africa were interviewed. Respondents expressed diverging attitudes toward predators, which were more favorable among participants with higher education. Negative views were particularly due to fear of human and livestock losses, especially to lions, Panthera leo. Lions were thought to be the most abundant predator both within and outside the reserve. Lions were also the best known predator and were most often held responsible for killing livestock. Despite these livestock losses and a lack of conservation education, most participants voiced favorable opinions about large carnivore conservation, as predators were considered an integral part of the respondents’ natural heritage. Thanks to this cultural tolerance and also because of a largely accepted management policy regarding predator control, large carnivores and people can coexist in the vicinity of Kruger National Park.

  12. Coexisting orchid species have distinct mycorrhizal communities and display strong spatial segregation.

    Science.gov (United States)

    Jacquemyn, Hans; Brys, Rein; Merckx, Vincent S F T; Waud, Michael; Lievens, Bart; Wiegand, Thorsten

    2014-04-01

    Because orchids are dependent on mycorrhizal fungi for germination and establishment of seedlings, differences in the mycorrhizal communities associating with orchids can be expected to mediate the abundance, spatial distribution and coexistence of terrestrial orchids in natural communities. We assessed the small-scale spatial distribution of seven orchid species co-occurring in 25 × 25 m plots in two Mediterranean grasslands. In order to characterize the mycorrhizal community associating with each orchid species, 454 pyrosequencing was used. The extent of spatial clustering was assessed using techniques of spatial point pattern analysis. The community of mycorrhizal fungi consisted mainly of members of the Tulasnellaceae, Thelephoraceae and Ceratobasidiaceae, although sporadically members of the Sebacinaceae, Russulaceae and Cortinariaceae were observed. Pronounced differences in mycorrhizal communities were observed between species, whereas strong clustering and significant segregation characterized the spatial distribution of orchid species. However, spatial segregation was not significantly related to phylogenetic dissimilarity of fungal communities. Our results indicate that co-occurring orchid species have distinctive mycorrhizal communities and show strong spatial segregation, suggesting that mycorrhizal fungi are important factors driving niche partitioning in terrestrial orchids and may therefore contribute to orchid coexistence.

  13. Gaseous abundances in M82

    CERN Document Server

    Ranalli, P; Origlia, L; Maiolino, R; Makishima, K; Ranalli, Piero; Comastri, Andrea; Origlia, Livia; Maiolino, Roberto; Makishima, Kazuo

    2005-01-01

    We present the preliminary analysis of a deep (100ks) XMM-Newton observation of M82. The spatial distribution of the abundances of chemical elements (Fe, O, Ne, Mg, Si, S) is investigated through narrow-band imaging analisys and spatially-resolved spectroscopy. We find that the abundances of alpha-elements follow a bipolar distribution, these elements being more abundant in the gaseous outflow than in the galaxy centre. This behaviour is found to be more marked for lighter elements (O, Ne) than for heavier elements.

  14. Coexistence of competing metabolic pathways in well-mixed populations

    Science.gov (United States)

    Fernández, Lenin; Amado, André; Campos, Paulo R. A.; Ferreira, Fernando Fagundes

    2016-05-01

    Understanding why strains with different metabolic pathways that compete for a single limiting resource coexist is a challenging issue within a theoretical perspective. Previous investigations rely on mechanisms such as group or spatial structuring to achieve a stable coexistence between competing metabolic strategies. Nevertheless, coexistence has been experimentally reported even in situations where it cannot be attributed to spatial effects [Heredity 100, 471 (2008), 10.1038/sj.hdy.6801073]. According to that study a toxin expelled by one of the strains can be responsible for the stable maintenance of the two strain types. We propose a resource-based model in which an efficient strain with a slow metabolic rate competes with a second strain type which presents a fast but inefficient metabolism. Moreover, the model assumes that the inefficient strain produces a toxin as a by-product. This toxin affects the growth rate of both strains with different strength. Through an extensive exploration of the parameter space we determine the situations at which the coexistence of the two strains is possible. Interestingly, we observe that the resource influx rate plays a key role in the maintenance of the two strain types. In a scenario of resource scarcity the inefficient is favored, though as the resource influx rate is augmented the coexistence becomes possible and its domain is enlarged.

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

    Science.gov (United States)

    Altieri, Andrew H; Irving, Andrew D

    2017-01-01

    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, despite the lack of a

  16. 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

  17. Chlorine Abundances in Cool Stars

    CERN Document Server

    Maas, Z G; Hinkle, K

    2016-01-01

    Chlorine abundances are reported in 15 evolved giants and one M dwarf in the solar neighborhood. The Cl abundance was measured using the vibration-rotation 1-0 P8 line of H$^{35}$Cl at 3.69851 $\\mu$m. The high resolution L-band spectra were observed using the Phoenix infrared spectrometer on the Kitt Peak Mayall 4m telescope. The average [$^{35}$Cl/Fe] abundance in stars with --0.72$<$[Fe/H]$<$0.20 is [$^{35}$Cl/Fe]=(--0.10$\\pm$0.15) dex. The mean difference between the [$^{35}$Cl/Fe] ratios measured in our stars and chemical evolution model values is (0.16$\\pm$0.15) dex. The [$^{35}$Cl/Ca] ratio has an offset of $\\sim$0.35 dex above model predictions suggesting chemical evolution models are under producing Cl at the high metallicity range. Abundances of C, N, O, Si, and Ca were also measured in our spectral region and are consistent with F and G dwarfs. The Cl versus O abundances from our sample match Cl abundances measured in planetary nebula and \\ion{H}{2} regions. In one star where both H$^{35}$Cl a...

  18. [Coexistence of coeliac disease and inflammatory bowel disease in children].

    Science.gov (United States)

    Krawiec, Paulina; Pawłowska-Kamieniak, Agnieszka; Pac-Kożuchowska, Elżbieta; Mroczkowska-Juchkiewcz, Agnieszka; Kominek, Katarzyna

    2016-01-01

    Coeliac disease and inflammatory bowel disease are chronic inflammatory conditions of gastrointestinal tract with complex aetiology with genetic, environmental and immunological factors contributing to its pathogenesis. It was noted that immune-mediated disorders often coexist. There is well-known association between coeliac disease and type 1 diabetes and ulcerative colitis and primary sclerosing cholangitis. However, growing body of literature suggests the association between coeliac disease and inflammatory bowel disease, particularly ulcerative colitis. This is an extremely rare problem in paediatric gastroenterology. To date there have been reported several cases of children with coexisting coeliac disease and inflammatory bowel disease. Herewith we present review of current literature on coexistence of coeliac disease and inflammatory bowel disease in children. © 2016 MEDPRESS.

  19. A Case of hereditary spherocytosis coexisting with Gilbert's syndrome.

    Science.gov (United States)

    Lee, Min Jae; Chang, Yoon Hwan; Kang, Seung Hwa; Mun, Se Kwon; Kim, Heyjin; Han, Chul Ju; Kim, Jin; Kang, Hye Jin

    2013-03-25

    We recently encountered a case of hereditary spherocytosis coexisting with Gilbert's syndrome. Patient was initially diagnosed with Gilbert's syndrome and observed, but other findings suggestive of concurrent hemolysis, such as splenomegaly and gallstones were noted during the follow-up period. Therefore, further evaluations, including a peripheral blood smear, osmotic fragility test, autohemolysis test, and red blood cell membrane protein test were performed, and coexisting hereditary spherocytosis was diagnosed. Genotyping of the conjugation enzyme uridine diphosphate-glucuronosyltransferase was used to confirm Gilbert's syndrome. Because of the high prevalence rates and similar symptoms of these 2 diseases, hereditary spherocytosis can be masked in patients with Gilbert's syndrome. In review of a case and other article, the possibility of the coexistence of these 2 diseases should be considered, especially in patients with unconjugated hyperbilirubinemia who also have splenomegaly and gallstones.

  20. 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.

  1. 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...

  2. 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.

  3. Performance Analysis on the Coexistence of Multiple Cognitive Radio Networks

    Directory of Open Access Journals (Sweden)

    Lijun Qian

    2015-05-01

    Full Text Available The demand for wireless services is growing on a daily basis while spectral resources to support this growth are static. Therefore, there is need for the adoption of a new spectrum sharing paradigm. Cognitive Radio (CR is a revolutionary technology aiming to increase spectrum utilization through dynamic spectrum access, as well as mitigating interference among multiple coexisting wireless networks. In many practical scenarios, multiple CR networks may coexist in the same geographical area, and they may interfere with each other and also have to yield to the primary user (PU. In this study, we investigate how much throughput a node in a CR network can achieve in the presence of another CR network and a PU. The results of this study illustrate how the transmission probability and sensing performance affect the achievable throughput of a node in coexisting CR networks. In addition, these results may serve as guidance for the deployment of multiple CR networks.

  4. Imaging the elusive H-poor gas in planetary nebulae with large abundance discrepancy factors

    CERN Document Server

    García-Rojas, J; Boffin, H M J; Monteiro, H; Jones, D; Wesson, R; Cabrera-Lavers, A; Rodríguez-Gil, P

    2016-01-01

    The discrepancy between abundances computed using optical recombination lines (ORLs) and collisionally excited lines (CELs) is a major, unresolved problem with significant implications for the determination of chemical abundances throughout the Universe. In planetary nebulae (PNe), the most common explanation for the discrepancy is that two different gas phases coexist: a hot component with standard metallicity, and a much colder plasma enhanced in heavy elements. This dual nature is not predicted by mass loss theories, and direct observational support for it is still weak. In this work, we present our recent findings that demonstrate that the largest abundance discrepancies are associated with close binary central stars. OSIRIS-GTC tunable filter imaging of the faint O II ORLs and MUSE-VLT deep 2D spectrophotometry confirm that O II ORL emission is more centrally concentrated than that of [O III] CELs and, therefore, that the abundance discrepancy may be closely linked to binary evolution.

  5. Species with greater seed mass are more tolerant of conspecific neighbours: a key driver of early survival and future abundances in a tropical forest.

    Science.gov (United States)

    Lebrija-Trejos, Edwin; Reich, Peter B; Hernández, Andres; Wright, S Joseph

    2016-09-01

    Multiple niche-based processes including conspecific negative density dependence (CNDD) determine plant regeneration and community structure. We ask how interspecific and intraspecific density-dependent interactions relate to plant life histories and associated functional traits. Using hierarchical models, we analysed how such interactions affected first-year survival of seedling recruits of 175 species in a tropical forest, and how species abundances and functional traits are related to interspecific variation in density-dependent effects. Conspecific seedling neighbour effects prevailed over the effects of larger conspecific and all heterospecific neighbours. Tolerance of seedling CNDD enhanced recruit survival and subsequent abundance, all of which were greater among larger seeded, slow-growing and well-defended species. Niche differentiation along the growth-survival trade-off and tolerance of seedling CNDD strongly correlated with regeneration success, with manifest consequences for community structure. The ability of larger seeded species to better tolerate CNDD suggests a novel mechanism for CNDD to contribute to seed-size variation and promote species coexistence through a tolerance-fecundity trade-off. © 2016 John Wiley & Sons Ltd/CNRS.

  6. Wi-Fi Coexistence with Duty Cycled LTE-U

    OpenAIRE

    Pang, Yimin; Babaei, Alireza; Andreoli-Fang, Jennifer; Hamzeh, Belal

    2016-01-01

    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 transmit their signals only in predetermined duty cycles. Wi-Fi stations, on the other hand, simply contend the shared channel using the distributed coordinati...

  7. 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.

  8. Phase Coexistence in Gallium Nanoparticles Controlled by Electron Excitation

    Science.gov (United States)

    Pochon, S.; MacDonald, K. F.; Knize, R. J.; Zheludev, N. I.

    2004-04-01

    In gallium nanoparticles 100nm in diameter grown on the tip of an optical fiber from an atomic beam we observed equilibrium coexistence of γ, β, and liquid structural phases that can be controlled by e-beam excitation in a highly reversible and reproducible fashion. With 2keV electrons only 1pJ of excitation energy per nanoparticle is needed to exercise control, with the equilibrium phase achieved in less than a few tenths of a microsecond. The transformations between coexisting phases are accompanied by a continuous change in the nanoparticle film's reflectivity.

  9. Coexistence and survival in conservative Lotka-Volterra networks.

    Science.gov (United States)

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

    2013-04-19

    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.

  10. 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...

  11. Sunspots, Starspots, and Elemental Abundances

    Science.gov (United States)

    Doschek, George A.; Warren, Harry P.

    2017-08-01

    The composition of plasma in solar and stellar atmospheres is not fixed, but varies from feature to feature. These variations are organized by the First Ionization Potential (FIP) of the element. Solar measurements often indicate that low FIP elements (10 eV, such as C, N, O, Ar, He) compared to abundances in the photosphere. Stellar observations have also shown similar enrichments. An inverse FIP effect, where the low FIP elements are depleted, has been observed in stellar coronae of stars believed to have large starspots in their photospheres. The abundances are important for determining radiative loss rates in models, tracing the origin of the slow solar wind, and for understanding wave propagation in the chromosphere and corona. Recently, inverse FIP effects have been discovered in the Sun (Doschek, Warren, & Feldman 2015, ApJ, 808, L7) from spectra obtained by the Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft. The inverse FIP regions seem always to be near sunspots and cover only a very small area (characteristic length = a few arcseconds). However, in pursuing the search for inverse FIP regions, we have found that in some sunspot groups the coronal abundance at a temperature of 3-4 MK can be near photospheric over much larger areas of the sun near the sunspots (e.g., 6,000 arcsec2). Also, sometimes the abundances at 3-4 MK are in between coronal and photospheric values. This can occur in small areas of an active region. It is predicted (Laming 2015, Sol. Phys., 12, 2) that the FIP effect should be highly variable in the corona. Several examples of coronal abundance variations are presented. Our work indicates that a comprehensive re-investigation of solar abundances is highly desirable. This work is supported by a NASA Hinode grant.

  12. Anthropogenic noise changes arthropod abundances.

    Science.gov (United States)

    Bunkley, Jessie P; McClure, Christopher J W; Kawahara, Akito Y; Francis, Clinton D; Barber, Jesse R

    2017-05-01

    Anthropogenic noise is a widespread and growing form of sensory pollution associated with the expansion of human infrastructure. One specific source of constant and intense noise is that produced by compressors used for the extraction and transportation of natural gas. Terrestrial arthropods play a central role in many ecosystems, and given that numerous species rely upon airborne sounds and substrate-borne vibrations in their life histories, we predicted that increased background sound levels or the presence of compressor noise would influence their distributions. In the second largest natural gas field in the United States (San Juan Basin, New Mexico, USA), we assessed differences in the abundances of terrestrial arthropod families and community structure as a function of compressor noise and background sound level. Using pitfall traps, we simultaneously sampled five sites adjacent to well pads that possessed operating compressors, and five alternate, quieter well pad sites that lacked compressors, but were otherwise similar. We found a negative association between sites with compressor noise or higher levels of background sound and the abundance of five arthropod families and one genus, a positive relationship between loud sites and the abundance of one family, and no relationship between noise level or compressor presence and abundance for six families and two genera. Despite these changes, we found no evidence of community turnover as a function of background sound level or site type (compressor and noncompressor). Our results indicate that anthropogenic noise differentially affects the abundances of some arthropod families. These preliminary findings point to a need to determine the direct and indirect mechanisms driving these observed responses. Given the diverse and important ecological functions provided by arthropods, changes in abundances could have ecological implications. Therefore, we recommend the consideration of arthropods in the environmental

  13. Coexistence of electron and hole transport in graphene

    NARCIS (Netherlands)

    Wiedmann, S.; van Elferen, H. J.; Kurganova, E. V.; Katsnelson, M. I.; Giesbers, A. J. M.; Veligura, A.; van Wees, B. J.; Gorbachev, R. V.; Novoselov, K. S.; Maan, J. C.; Zeitler, U.

    2011-01-01

    When sweeping the carrier concentration in monolayer graphene through the charge neutrality point, the experimentally measured Hall resistivity shows a smooth zero crossing. Using a two-component model of coexisting electrons and holes around the charge neutrality point, we unambiguously show that b

  14. Coexistence and exclusion of stochastic competitive Lotka-Volterra models

    Science.gov (United States)

    Nguyen, Dang H.; Yin, George

    2017-02-01

    This work derives sufficient conditions for the coexistence and exclusion of a stochastic competitive Lotka-Volterra model. The conditions obtained are close to necessary. In addition, convergence in distribution of positive solutions of the model is also established. A number of numerical examples are given to illustrate our results.

  15. Coexistence of endocrinopathies in children with rheumatic diseases

    Directory of Open Access Journals (Sweden)

    Doha Alhomaidah

    2016-09-01

    Conclusion: Our findings demonstrated that coexistence of endocrinopathies is not uncommon in children diagnosed with JIA and SLE. Abnormal thyroid function occurs frequently and at a similar rate in children diagnosed with SLE and JIA. Thus, screening for endocrinopathies, namely thyroid disease, during the assessment of childhood SLE and JIA is worth consideration.

  16. Climate change threatens coexistence within communities of Mediterranean forested wetlands.

    Science.gov (United States)

    Di Paola, Arianna; Valentini, Riccardo; Paparella, Francesco

    2012-01-01

    The Mediterranean region is one of the hot spots of climate change. This study aims at understanding what are the conditions sustaining tree diversity in Mediterranean wet forests under future scenarios of altered hydrological regimes. The core of the work is a quantitative, dynamic model describing the coexistence of different Mediterranean tree species, typical of arid or semi-arid wetlands. Two kind of species, i.e. Hygrophilous (drought sensitive, flood resistant) and Non-hygrophilous (drought resistant, flood sensitive), are broadly defined according to the distinct adaptive strategies of trees against water stress of summer drought and winter flooding. We argue that at intermediate levels of water supply the dual role of water (resource and stress) results in the coexistence of the two kind of species. A bifurcation analysis allows us to assess the effects of climate change on the coexistence of the two species in order to highlight the impacts of predicted climate scenarios on tree diversity. Specifically, the model has been applied to Mediterranean coastal swamp forests of Central Italy located at Castelporziano Estate and Circeo National Park. Our results show that there are distinct rainfall thresholds beyond which stable coexistence becomes impossible. Regional climatic projections show that the lower rainfall threshold may be approached or crossed during the XXI century, calling for an urgent adaptation and mitigation response to prevent biodiversity losses.

  17. Killer-sensitive coexistence in metapopulations of micro-organisms

    NARCIS (Netherlands)

    Czárán, T.L.; Hoekstra, R.F.

    2003-01-01

    Many micro-organisms are known to produce efficient toxic substances against conspecifics and closely related species. The widespread coexistence of killer (toxin producer) and sensitive (non-producer) strains is a puzzle calling for a theoretical explanation. Based on stochastic cellular automaton

  18. Synchronization in Coupled Oscillators with Two Coexisting Attractors

    Institute of Scientific and Technical Information of China (English)

    ZHU Han-Han; YANG Jun-Zhong

    2008-01-01

    Dynamics in coupled Duffing oscillators with two coexisting symmetrical attractors is investigated. For a pair of Dutffng 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.

  19. [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.

  20. 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...

  1. 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,…

  2. Climate change threatens coexistence within communities of Mediterranean forested wetlands.

    Directory of Open Access Journals (Sweden)

    Arianna Di Paola

    Full Text Available The Mediterranean region is one of the hot spots of climate change. This study aims at understanding what are the conditions sustaining tree diversity in Mediterranean wet forests under future scenarios of altered hydrological regimes. The core of the work is a quantitative, dynamic model describing the coexistence of different Mediterranean tree species, typical of arid or semi-arid wetlands. Two kind of species, i.e. Hygrophilous (drought sensitive, flood resistant and Non-hygrophilous (drought resistant, flood sensitive, are broadly defined according to the distinct adaptive strategies of trees against water stress of summer drought and winter flooding. We argue that at intermediate levels of water supply the dual role of water (resource and stress results in the coexistence of the two kind of species. A bifurcation analysis allows us to assess the effects of climate change on the coexistence of the two species in order to highlight the impacts of predicted climate scenarios on tree diversity. Specifically, the model has been applied to Mediterranean coastal swamp forests of Central Italy located at Castelporziano Estate and Circeo National Park. Our results show that there are distinct rainfall thresholds beyond which stable coexistence becomes impossible. Regional climatic projections show that the lower rainfall threshold may be approached or crossed during the XXI century, calling for an urgent adaptation and mitigation response to prevent biodiversity losses.

  3. 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...

  4. Direct determination of liquid phase coexistence by Monte Carlo simulations

    NARCIS (Netherlands)

    Zweistra, H.J.A.; Besseling, N.A.M.

    2006-01-01

    A formalism to determine coexistence points by means of Monte Carlo simulations is presented. The general idea of the method is to perform a simulation simultaneously in several unconnected boxes which can exchange particles. At equilibrium, most of the boxes will be occupied by a homogeneous phase.

  5. 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....

  6. Coexistence Steady States in a Predator-Prey Model

    CERN Document Server

    Walker, Christoph

    2010-01-01

    An age-structured predator-prey system with diffusion and Holling-Tanner-type nonlinearities is considered. Regarding the intensity of the fertility of the predator as bifurcation parameter, we prove that a branch of positive coexistence steady states bifurcates from the marginal steady state with no prey. A similar result is obtained when the fertility of the prey varies.

  7. Management of Adult Choledochal Cyst Coexisting with Gallbladder ...

    African Journals Online (AJOL)

    [1] It is a rare congenital anomaly which is, for unknown reasons, quite ... fever with chills and rigors. Physical ... Coexisting with Gallbladder Carcinoma: A Case Report and Review of. Literature. ... combination, and there is no evidence of recurrence during the ... differentiate choledochal cysts from other cause of obstructive.

  8. Coexistent physics of massive black holes in the phase transitions

    CERN Document Server

    Zhang, Ming

    2016-01-01

    The coexistent physics of de Rham-Gabada-dze-Tolley (dRGT) massive black holes and holographic massive black holes is investigated in the extended phase space where the cosmological constant is viewed as pressure. Van der Waals like phase transitions are found for both of them. Coexistent curves of reduced pressure and reduced temperature are found to be different from that of RN-AdS black holes. Coexistent curves of reduced Gibbs free energy and reduced pressure show that Gibbs free energy in the canonical ensemble decreases monotonically with the increasing pressure. The concept number density is introduced to study the coexistent physics. It is uncovered that with the increasing pressure, the number densities of small black holes (SBHs) and large black holes (LBHs) change monotonically in the contrary directions till finally reaching the same value at the critical points of the phase transitions. In other words, with the increasing pressure the number density differences between SBHs and LBHs decrease mono...

  9. 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...

  10. 78 FR 79660 - Enhancing Agricultural Coexistence; Extension of Comment Period

    Science.gov (United States)

    2013-12-31

    .... APHIS-2013-0047] Enhancing Agricultural Coexistence; Extension of Comment Period ACTION: Notice; extension of comment period. SUMMARY: We are extending the comment period for a request for information... persons additional time to prepare and submit comments. DATES: The comment period for the notice published...

  11. Coexistence of electron and hole transport in graphene

    NARCIS (Netherlands)

    Wiedmann, S.; van Elferen, H. J.; Kurganova, E. V.; Katsnelson, M. I.; Giesbers, A. J. M.; Veligura, A.; van Wees, B. J.; Gorbachev, R. V.; Novoselov, K. S.; Maan, J. C.; Zeitler, U.

    2011-01-01

    When sweeping the carrier concentration in monolayer graphene through the charge neutrality point, the experimentally measured Hall resistivity shows a smooth zero crossing. Using a two-component model of coexisting electrons and holes around the charge neutrality point, we unambiguously show that

  12. Coexistence of two species in a strongly coupled cooperating model

    DEFF Research Database (Denmark)

    Pedersen, Michael

    In this paper, the cooperating two-species Lotka-Volterra model is discussed. We study the existence of solutions to a elliptic system with homogeneous Dirichlet boundary conditions. Our results show that this problem possesses at least one coexistence state if the birth rates are big and self...

  13. The coexistence curve of finite charged nuclear matter

    Science.gov (United States)

    Elliott, J. B.; Moretto, L. G.; Phair, L.; Wozniak, G. J.; Beaulieu, L.; Breuer, H.; Korteling, R. G.; Kwiatkowski, K.; Lefort, T.; Pienkowski, L.; Ruangma, A.; Viola, V. E.; Yennello, S. J.; Albergo, S.; Bieser, F.; Brady, F. P.; Caccia, Z.; Cebra, D. A.; Chacon, A. D.; Chance, J. L.; Choi, Y.; Costa, S.; Gilkes, M. L.; Hauger, J. A.; Hirsch, A. S.; Hjort, E. L.; Insolia, A.; Justice, M.; Keane, D.; Kintner, J. C.; Lindenstruth, V.; Lisa, M. A.; Matis, H. S.; McMahan, M.; McParland, C.; Müller, W. F. J.; Olson, D. L.; Partlan, M. D.; Porile, N. T.; Potenza, R.; Rai, G.; Rasmussen, J.; Ritter, H. G.; Romanski, J.; Romero, J. L.; Russo, G. V.; Sann, H.; Scharenberg, R. P.; Scott, A.; Shao, Y.; Srivastava, B. K.; Symons, T. J. M.; Tincknell, M.; Tuvé, C.; Wang, S.; Warren, P.; Wieman, H. H.; Wienold, T.; Wolf, K.

    2002-04-01

    The multifragmentation data of the ISiS Collaboration and the EOS Collaboration are examined. Fisher's droplet formalism, modified to account for Coulomb energy, is used to determine the critical exponents τ and σ, the surface energy coefficient c0, the pressure-temperature-density coexistence curve of finite nuclear matter and the location of the critical point. .

  14. Coexistence of two species in a strongly coupled cooperating model

    DEFF Research Database (Denmark)

    Pedersen, Michael

    In this paper, the cooperating two-species Lotka-Volterra model is discussed. We study the existence of solutions to a elliptic system with homogeneous Dirichlet boundary conditions. Our results show that this problem possesses at least one coexistence state if the birth rates are big and self...

  15. 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.

  16. 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.

  17. Coexistence in a multispecies assemblage of eagles in central Asia

    Science.gov (United States)

    Katzner, T.E.; Bragin, E.A.; Knick, S.T.; Smith, A.T.

    2003-01-01

    We evaluated factors that permit species coexistence in an exceptional assemblage of similar raptor species at the Naurzum Zapovednik (a national nature reserve) in north-central Kazakhstan. White-tailed Sea-Eagle (Haliaeetus albicilla), Imperial Eagle (Aquila heliaca), Golden Eagle (A. chrysaetos), and Steppe Eagle (A. nipalensis) all breed at the Zapovednik. Steppe Eagle use of nesting resources was distinct from that of tree-nesting species. We evaluated differences in nest tree and nest habitat characteristics, nest dimensions and positions, and nest spacing among the three forest-dwelling eagle species to distinguish between the effects of inter- and intraspecific resource limitations on species coexistence. Although the different species bred in similar habitat and sometimes reused other species' nests, the dimensions, positions and locations of their nests often differed. These differences did not appear to result from interspecific competition. Nest spacing trends were also species specific; Imperial Eagles generally nested farther from other eagle nests than did Golden Eagles and White-tailed Sea-Eagles. Intraspecific variation in habitat, physical characteristics, and spacing patterns of Imperial Eagle nests was extensive throughout the nature reserve. Although interspecific partitioning of nesting habitat may allow coexistence of ground-nesting Steppe Eagles, interspecific competition did not appear to be a primary determinant of the use of nest habitat, space, or nests by tree-nesting species. Rather, interspecific effects appeared secondary to intraspecific effects in determining coexistence of tree-nesting eagles at this site.

  18. 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 pcr and temperatures Tcr 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 pr* to replace the previously used reduced pressure pr=p /pcr . We show that pr* 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 pr*, the extended corresponding states principle can be applied within corresponding states principle

  19. Coexistence of Two Congeneric Praying Mantids: A 7-Year Field Study of Reproductive Success and Failure.

    Science.gov (United States)

    Rose, Robert K; Hurd, Lawrence E

    2016-02-01

    Two species of Asian praying mantids, Tenodera angustipennis (Saussure) and Tenodera aridifolia sinensis (Saussure), which have become common to old fields in the northeastern United States, share a common resource base that raises the question of how they can coexist in the same habitat. We studied the reproductive output measured by numbers of oothecae of naturally established populations of these two species in an old field during 7 yr (2009–2015) of secondary succession. During the initial herbaceous vegetation-dominated stage, T. angustipennis oothecae were more abundant than those of its congener, but numbers steadily declined, until it had nearly disappeared by 2014. In contrast, numbers of T. a. sinensis oothecae increased from 2007 until 2014, and then sharply declined in 2015. The steady increase in abundance of this species throughout most of the successional development during the study may be owing to greater diversity of plant species used for oviposition. We believe that the most likely reasons for the continuous decline in T. angustipennis were a combination of intraguild predation by the larger T. a. sinensis, and egg parasitism by the wasp Podagrion mantis, which is not able to parasitize oothecae of T. a. sinensis. The later decline in T. a. sinensis may reflect the fact that the site had become dominated by trees, and neither of these species is typically found in forest habitats.

  20. 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

  1. Patchiness and co-existence of indigenous and invasive mussels at small spatial scales: the interaction of facilitation and competition.

    Science.gov (United States)

    Erlandsson, Johan; McQuaid, Christopher D; Sköld, Martin

    2011-01-01

    Ecological theory predicts that two species with similar requirements will fail to show long-term co-existence in situations where shared resources are limiting, especially at spatial scales that are small relative to the size of the organisms. Two species of intertidal mussels, the indigenous Perna perna and the invasive Mytilus galloprovincialis, form mixed beds on the south coast of South Africa in a situation that has been stable for several generations of these species, even though these populations are often limited by the availability of space. We examined the spatial structure of these species where they co-exist at small spatial scales in the absence of apparent environmental heterogeneity at two sites, testing: whether conspecific aggregation of mussels can occur (using spatial Monte-Carlo tests); the degree of patchiness (using Korcak B patchiness exponent), and whether there was a relationship between percent cover and patchiness. We found that under certain circumstances there is non-random conspecific aggregation, but that in other circumstances there may be random distribution (i.e. the two species are mixed), so that spatial patterns are context-dependent. The relative cover of the species differed between sites, and within each site, the species with higher cover showed low Korcak B values (indicating low patchiness, i.e. the existence of fewer, larger patches), while the less abundant species showed the reverse, i.e. high patchiness. This relationship did not hold for either species within sites. We conclude that co-existence between these mussels is possible, even at small spatial scales because each species is an ecological engineer and, while they have been shown to compete for space, this is preceded by initial facilitation. We suggest that a patchy pattern of co-existence is possible because of a balance between direct (competitive) and indirect (facilitative) interactions.

  2. Patchiness and co-existence of indigenous and invasive mussels at small spatial scales: the interaction of facilitation and competition.

    Directory of Open Access Journals (Sweden)

    Johan Erlandsson

    Full Text Available Ecological theory predicts that two species with similar requirements will fail to show long-term co-existence in situations where shared resources are limiting, especially at spatial scales that are small relative to the size of the organisms. Two species of intertidal mussels, the indigenous Perna perna and the invasive Mytilus galloprovincialis, form mixed beds on the south coast of South Africa in a situation that has been stable for several generations of these species, even though these populations are often limited by the availability of space. We examined the spatial structure of these species where they co-exist at small spatial scales in the absence of apparent environmental heterogeneity at two sites, testing: whether conspecific aggregation of mussels can occur (using spatial Monte-Carlo tests; the degree of patchiness (using Korcak B patchiness exponent, and whether there was a relationship between percent cover and patchiness. We found that under certain circumstances there is non-random conspecific aggregation, but that in other circumstances there may be random distribution (i.e. the two species are mixed, so that spatial patterns are context-dependent. The relative cover of the species differed between sites, and within each site, the species with higher cover showed low Korcak B values (indicating low patchiness, i.e. the existence of fewer, larger patches, while the less abundant species showed the reverse, i.e. high patchiness. This relationship did not hold for either species within sites. We conclude that co-existence between these mussels is possible, even at small spatial scales because each species is an ecological engineer and, while they have been shown to compete for space, this is preceded by initial facilitation. We suggest that a patchy pattern of co-existence is possible because of a balance between direct (competitive and indirect (facilitative interactions.

  3. The primordial helium abundance from updated emissivities

    Energy Technology Data Exchange (ETDEWEB)

    Aver, Erik [Department of Physics, Gonzaga University, 502 E Boone Ave, Spokane, WA, 99258 (United States); Olive, Keith A.; Skillman, Evan D. [School of Physics and Astronomy, University of Minnesota, 116 Church St. SE, Minneapolis, MN, 55455 (United States); Porter, R.L., E-mail: aver@gonzaga.edu, E-mail: olive@umn.edu, E-mail: ryanlporter@gmail.com, E-mail: skillman@astro.umn.edu [Department of Physics and Astronomy, University of Georgia, Athens, GA, 30602 (United States)

    2013-11-01

    Observations of metal-poor extragalactic H II regions allow the determination of the primordial helium abundance, Y{sub p}. The He I emissivities are the foundation of the model of the H II region's emission. Porter, Ferland, Storey, and Detisch (2012) have recently published updated He I emissivities based on improved photoionization cross-sections. We incorporate these new atomic data and update our recent Markov Chain Monte Carlo analysis of the dataset published by Izotov, Thuan, and Stasi'nska (2007). As before, cuts are made to promote quality and reliability, and only solutions which fit the data within 95% confidence level are used to determine the primordial He abundance. The previously qualifying dataset is almost entirely retained and with strong concordance between the physical parameters. Overall, an upward bias from the new emissivities leads to a decrease in Y{sub p}. In addition, we find a general trend to larger uncertainties in individual objects (due to changes in the emissivities) and an increased variance (due to additional objects included). From a regression to zero metallicity, we determine Y{sub p} = 0.2465 ± 0.0097, in good agreement with the BBN result, Y{sub p} = 0.2485 ± 0.0002, based on the Planck determination of the baryon density. In the future, a better understanding of why a large fraction of spectra are not well fit by the model will be crucial to achieving an increase in the precision of the primordial helium abundance determination.

  4. Hf Transition Probabilities and Abundances

    CERN Document Server

    Lawler, J E; Labby, Z E; Sneden, C; Cowan, J J; Ivans, I I

    2006-01-01

    Radiative lifetimes from laser-induced fluorescence measurements, accurate to about +/- 5 percent, are reported for 41 odd-parity levels of Hf II. The lifetimes are combined with branching fractions measured using Fourier transform spectrometry to determine transition probabilities for 150 lines of Hf II. Approximately half of these new transition probabilities overlap with recent independent measurements using a similar approach. The two sets of measurements are found to be in good agreement for measurements in common. Our new laboratory data are applied to refine the hafnium photospheric solar abundance and to determine hafnium abundances in 10 metal-poor giant stars with enhanced r-process abundances. For the Sun we derive log epsilon (Hf) = 0.88 +/- 0.08 from four lines; the uncertainty is dominated by the weakness of the lines and their blending by other spectral features. Within the uncertainties of our analysis, the r-process-rich stars possess constant Hf/La and Hf/Eu abundance ratios, log epsilon (Hf...

  5. Gd Transition Probabilities and Abundances

    CERN Document Server

    Den Hartog, E A; Sneden, C; Cowan, J J

    2006-01-01

    Radiative lifetimes, accurate to +/- 5%, have been measured for 49 even-parity and 14 odd-parity levels of Gd II using laser-induced fluorescence. The lifetimes are combined with branching fractions measured using Fourier transform spectrometry to determine transition probabilities for 611 lines of Gd II. This work is the largest-scale laboratory study to date of Gd II transition probabilities and the first using a high performance Fourier transform spectrometer. This improved data set has been used to determine a new solar photospheric Gd abundance, log epsilon = 1.11 +/- 0.03. Revised Gd abundances have also been derived for the r-process-rich metal-poor giant stars CS 22892-052, BD+17 3248, and HD 115444. The resulting Gd/Eu abundance ratios are in very good agreement with the solar-system r-process ratio. We have employed the increasingly accurate stellar abundance determinations, resulting in large part from the more precise laboratory atomic data, to predict directly the Solar System r-process elemental...

  6. The Coexistence of "Expressionism"and "Experimentalism"-Two Different Performance System Coexist in Film Happy Together

    Institute of Scientific and Technical Information of China (English)

    文静

    2011-01-01

    How to deal with the relations between roles and actors is the core question of the performance,and there are two opposite performance theories to this question:"Expressionism"and "Experimentalism".Can these two different performance styles coexist harmoniously? The film Happy Together directed by Karwai Wong has provided a very good answer.

  7. Coho Abundance - Linear Features [ds183

    Data.gov (United States)

    California Department of Resources — The CalFish Abundance Database contains a comprehensive collection of anadromous fisheries abundance information. Beginning in 1998, the Pacific States Marine...

  8. Steelhead Abundance - Point Features [ds184

    Data.gov (United States)

    California Department of Resources — The CalFish Abundance Database contains a comprehensive collection of anadromous fisheries abundance information. Beginning in 1998, the Pacific States Marine...

  9. Steelhead Abundance - Linear Features [ds185

    Data.gov (United States)

    California Department of Resources — The CalFish Abundance Database contains a comprehensive collection of anadromous fisheries abundance information. Beginning in 1998, the Pacific States Marine...

  10. Coho Abundance - Point Features [ds182

    Data.gov (United States)

    California Department of Resources — The CalFish Abundance Database contains a comprehensive collection of anadromous fisheries abundance information. Beginning in 1998, the Pacific States Marine...

  11. Chinook Abundance - Point Features [ds180

    Data.gov (United States)

    California Department of Resources — The CalFish Abundance Database contains a comprehensive collection of anadromous fisheries abundance information. Beginning in 1998, the Pacific States Marine...

  12. Abundance estimation and Conservation Biology

    Directory of Open Access Journals (Sweden)

    Nichols, J. D.

    2004-06-01

    Full Text Available Abundance is the state variable of interest in most population–level ecological research and in most programs involving management and conservation of animal populations. Abundance is the single parameter of interest in capture–recapture models for closed populations (e.g., Darroch, 1958; Otis et al., 1978; Chao, 2001. The initial capture–recapture models developed for partially (Darroch, 1959 and completely (Jolly, 1965; Seber, 1965 open populations represented efforts to relax the restrictive assumption of population closure for the purpose of estimating abundance. Subsequent emphases in capture–recapture work were on survival rate estimation in the 1970’s and 1980’s (e.g., Burnham et al., 1987; Lebreton et al.,1992, and on movement estimation in the 1990’s (Brownie et al., 1993; Schwarz et al., 1993. However, from the mid–1990’s until the present time, capture–recapture investigators have expressed a renewed interest in abundance and related parameters (Pradel, 1996; Schwarz & Arnason, 1996; Schwarz, 2001. The focus of this session was abundance, and presentations covered topics ranging from estimation of abundance and rate of change in abundance, to inferences about the demographic processes underlying changes in abundance, to occupancy as a surrogate of abundance. The plenary paper by Link & Barker (2004 is provocative and very interesting, and it contains a number of important messages and suggestions. Link & Barker (2004 emphasize that the increasing complexity of capture–recapture models has resulted in large numbers of parameters and that a challenge to ecologists is to extract ecological signals from this complexity. They offer hierarchical models as a natural approach to inference in which traditional parameters are viewed as realizations of stochastic processes. These processes are governed by hyperparameters, and the inferential approach focuses on these hyperparameters. Link & Barker (2004 also suggest that

  13. Abundance estimation and conservation biology

    Science.gov (United States)

    Nichols, J.D.; MacKenzie, D.I.

    2004-01-01

    Abundance is the state variable of interest in most population–level ecological research and in most programs involving management and conservation of animal populations. Abundance is the single parameter of interest in capture–recapture models for closed populations (e.g., Darroch, 1958; Otis et al., 1978; Chao, 2001). The initial capture–recapture models developed for partially (Darroch, 1959) and completely (Jolly, 1965; Seber, 1965) open populations represented efforts to relax the restrictive assumption of population closure for the purpose of estimating abundance. Subsequent emphases in capture–recapture work were on survival rate estimation in the 1970’s and 1980’s (e.g., Burnham et al., 1987; Lebreton et al.,1992), and on movement estimation in the 1990’s (Brownie et al., 1993; Schwarz et al., 1993). However, from the mid–1990’s until the present time, capture–recapture investigators have expressed a renewed interest in abundance and related parameters (Pradel, 1996; Schwarz & Arnason, 1996; Schwarz, 2001). The focus of this session was abundance, and presentations covered topics ranging from estimation of abundance and rate of change in abundance, to inferences about the demographic processes underlying changes in abundance, to occupancy as a surrogate of abundance. The plenary paper by Link & Barker (2004) is provocative and very interesting, and it contains a number of important messages and suggestions. Link & Barker (2004) emphasize that the increasing complexity of capture–recapture models has resulted in large numbers of parameters and that a challenge to ecologists is to extract ecological signals from this complexity. They offer hierarchical models as a natural approach to inference in which traditional parameters are viewed as realizations of stochastic processes. These processes are governed by hyperparameters, and the inferential approach focuses on these hyperparameters. Link & Barker (2004) also suggest that our attention

  14. Sm Transition Probabilities and Abundances

    CERN Document Server

    Lawler, J E; Sneden, C; Cowan, J J

    2005-01-01

    Radiative lifetimes, accurate to +/- 5%, have been measured for 212 odd-parity levels of Sm II using laser-induced fluorescence. The lifetimes are combined with branching fractions measured using Fourier-transform spectrometry to determine transition probabilities for more than 900 lines of Sm II. This work is the largest-scale laboratory study to date of Sm II transition probabilities using modern methods. This improved data set has been used to determine a new solar photospheric Sm abundance, log epsilon = 1.00 +/- 0.03, from 26 lines. The spectra of three very metal-poor, neutron-capture-rich stars also have been analyzed, employing between 55 and 72 Sm II lines per star. The abundance ratios of Sm relative to other rare earth elements in these stars are in agreement, and are consistent with ratios expected from rapid neutron-capture nucleosynthesis (the r-process).

  15. Element abundances at high redshift

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, D.M.; Welty, D.E.; York, D.G. (Northwestern Univ., Evanston, IL (USA); Chicago Univ., IL (USA))

    1989-08-01

    Abundances of Si(+), S(+), Cr(+), Mn(+), Fe( ), and Zn(+) are considered for two absorption-line systems in the spectrum of the QSO PKS 0528 - 250. Zinc and sulfur are underabundant, relative to H, by a factor of 10 compared to their solar and Galactic interstellar abundances. The silicon-, chromium-, iron-, and nickel-to-hydrogen ratios are less than the solar values and comparable to the local interstellar ratios. A straightforward interpretation is that nucleosynthesis in these high-redshift systems has led to only about one-tenth as much heavy production as in the gas clouds around the sun, and that the amount of the observed underabundances attributable to grain depletion is small. The dust-to-gas ratio in these clouds is less than 8 percent of the Galactic value. 25 refs.

  16. Element abundances at high redshift

    Science.gov (United States)

    Meyer, David M.; Welty, D. E.; York, D. G.

    1989-01-01

    Abundances of Si(+), S(+), Cr(+), Mn(+), Fe(_), and Zn(+) are considered for two absorption-line systems in the spectrum of the QSO PKS 0528 - 250. Zinc and sulfur are underabundant, relative to H, by a factor of 10 compared to their solar and Galactic interstellar abundances. The silicon-, chromium-, iron-, and nickel-to-hydrogen ratios are less than the solar values and comparable to the local interstellar ratios. A straightforward interpretation is that nucleosynthesis in these high-redshift systems has led to only about one-tenth as much heavy production as in the gas clouds around the sun, and that the amount of the observed underabundances attributable to grain depletion is small. The dust-to-gas ratio in these clouds is less than 8 percent of the Galactic value.

  17. Coexistence of primary myelofibrosis and chronic lymphocytic leukemia

    Directory of Open Access Journals (Sweden)

    Burgstaller S

    2014-10-01

    Full Text Available Sonja Burgstaller, Josef Thaler Klinikum Wels-Grieskirchen, Abteilung für Innere Medizin IV, Wels, AustriaAbstract: Coexistence of two hematologic malignancies in one patient is generally a rare phenomenon. The topic of this article is the coincidence of primary myelofibrosis and chronic lymphocytic leukemia, which has been reported up to now in only 16 patients. In summary, simultaneous detection of both diseases was notable in half of the patients at presentation. In the case of a subsequent diagnosis of both disorders, primary myelofibrosis preceded the lymphoproliferative disease in the majority of patients. The clinical course seems to be more benign than for each disorder itself. A substantial proportion of patients did not require any treatment at all. Knowledge about the pathogenetic mechanisms, treatment approaches, and prognosis of these patients is limited.Keywords: primary myelofibrosis, chronic lymphocytic leukemia, coexistent

  18. Time scales and species coexistence in chaotic flows

    CERN Document Server

    Galla, Tobias

    2016-01-01

    Empirical observations in marine ecosystems have suggested a balance of biological and advection time scales as a possible explanation of species coexistence. To characterise this scenario, we measure the time to fixation in neutrally evolving populations in chaotic flows. Contrary to intuition the variation of time scales does not interpolate straightforwardly between the no-flow and well-mixed limits; instead we find that fixation is the slowest at intermediate Damk\\"ohler numbers, indicating long-lasting coexistence of species. Our analysis shows that this slowdown is due to spatial organisation on an increasingly modularised network. We also find that diffusion can either slow down or speed up fixation, depending on the relative time scales of flow and evolution.

  19. What Coexists with the Ferromagnetic Metallic Phase in Manganites?

    Energy Technology Data Exchange (ETDEWEB)

    Burkhardt, Mark H.; Hossain, M.A.; Sarkar, S.; Achkar, A.J.; Hawthorn, D.G.; Sutarto, R.; Chuang, 5 Y.-D.; Gonzalez, A.G.Cruz; Choi, Y.J.; Cheong, S.-W.; Durr, H.A.; Stohr, J.

    2012-07-25

    Colossal magnetoresistance, whereby the application of a magnetic field reduces the resistivity of a manganite by orders of magnitude, is generally believed to occur because of coexisting phases. Development of a complete theory to explain the phenomenon requires that the exact nature of these phases be known. We used resonant elastic soft x-ray scattering to examine the superlattice order that exists in La{sub 0.35}Pr{sub 0.275}Ca{sub 0.375}MnO{sub 3} above and below the Curie temperature. By measuring the resonance profile of the scattered x-rays at different values of q, we disentangle the contributions of orbital order and antiferromagnetism to the scattering signal above the Curie temperature. Below the Curie temperature, we see no signal from orbital order, and only antiferromagnetism coexists with the dominant ferromagnetic metallic phase.

  20. Management of chronic rhinosinusitis with nasal polyps and coexisting asthma

    DEFF Research Database (Denmark)

    Rix, Iben; Håkansson, Kåre; Larsen, Christian Grønhøj

    2015-01-01

    BACKGROUND: Chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP) and asthma are strongly associated, and patients suffering from both diseases are often difficult to treat. However, no guidelines about the management of patients with CRS and coexisting asthma exist. OBJECTIVE: The purpose...... of this systematic review was to evaluate the management of CRSwNP and coexisting asthma. METHODS: We systematically searched electronic databases and included clinical trials in which the clinical outcomes after medical or surgical treatment of patients with CRSwNP and asthma were assessed. The strength...... of the evidence for each outcome was graded on the basis of study quality and consistency in findings. RESULTS: We included seven trials in which the effect of montelukast, omalizumab, erythromycin, and functional endoscopic sinus surgery (FESS) were studied in 317 adults with CRSwNP and asthma. All...

  1. Coexistence of pneumothorax and chilaiditi sign:A case report

    Institute of Scientific and Technical Information of China (English)

    Tangri Nitin; Singhal Sameer; Sharma Priyanka; Mehta Dinesh; Bansal Sachin; Bhushan Neeraj; Singla Sulbha; Singh Puneet

    2014-01-01

    We present a case of 50 year old male patient with coexistence of Pneumothorax and Chilaiditi sign. Chilaiditi sign is an incidental radiographic finding of a usually asymptomatic condition in which a part of intestine is located between the liver and diaphragm; however, the term“Chilaiditi syndrome”is used for symptomatic hepatodiaphragmatic interposition. The patient had no symptoms of abdominal pain, constipation, diarrhea, or emesis. Incidentally, Chilaiditi sign was diagnosed on chest radiography. Pneumothorax is defined as air in the pleural space. Pneumothoraces are classified as spontaneous or traumatic. Spontaneous pneumothorax is labelled as primary when no underlying lung disease is present, or secondary, when it is associated with pre-existing lung disease. Our case is the rare in the literature indicating the coexistence of Chilaiditi sign and pneumothorax.

  2. Pattern formation and coexistence domains for a nonlocal population dynamics

    CERN Document Server

    da Cunha, J A R; Oliveira, F A

    2011-01-01

    In this communication we propose a most general equation to study pattern formation for one-species population and their limit domains in systems of length L. To accomplish this we include non-locality in the growth and competition terms where the integral kernels are now depend on characteristic length parameters alpha and beta. Therefore, we derived a parameter space (alpha,beta) where it is possible to analyze a coexistence curve alpha*=alpha*(\\beta) which delimits domains for the existence (or not) of pattern formation in population dynamics systems. We show that this curve has an analogy with coexistence curve in classical thermodynamics and critical phenomena physics. We have successfully compared this model with experimental data for diffusion of Escherichia coli populations.

  3. Geometric constraints on phase coexistence in vanadium dioxide single crystals

    Science.gov (United States)

    McGahan, Christina; Gamage, Sampath; Liang, Jiran; Cross, Brendan; Marvel, Robert E.; Haglund, Richard F.; Abate, Yohannes

    2017-02-01

    The appearance of stripe phases is a characteristic signature of strongly correlated quantum materials, and its origin in phase-changing materials has only recently been recognized as the result of the delicate balance between atomic and mesoscopic materials properties. A vanadium dioxide (VO2) single crystal is one such strongly correlated material with stripe phases. Infrared nano-imaging on low-aspect-ratio, single-crystal VO2 microbeams decorated with resonant plasmonic nanoantennas reveals a novel herringbone pattern of coexisting metallic and insulating domains intercepted and altered by ferroelastic domains, unlike previous reports on high-aspect-ratio VO2 crystals where the coexisting metal/insulator domains appear as alternating stripe phases perpendicular to the growth axis. The metallic domains nucleate below the crystal surface and grow towards the surface with increasing temperature as suggested by the near-field plasmonic response of the gold nanorod antennas.

  4. Ecology 2.0: Coexistence and Domination of Interacting Networks

    CERN Document Server

    Kleineberg, Kaj-Kolja

    2014-01-01

    The overwhelming success of the web 2.0, with online social networks as key actors, has induced a paradigm shift in the nature of human interactions. The user-driven character of these services for the first time has allowed researchers to quantify large-scale social patterns. However, the mechanisms that determine the fate of networks at a system level are still poorly understood. For instance, the simultaneous existence of numerous digital services naturally raises the question under which conditions these services can coexist. In analogy to population dynamics, the digital world is forming a complex ecosystem of interacting networks whose fitnesses depend on their ability 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 a stable coexistence of several networks as well as the domination of a single one, in contrast to the principle of competitive exclusion. Interestingly, our model also predic...

  5. Thermodynamics and phase coexistence in nonequilibrium steady states

    Science.gov (United States)

    Dickman, Ronald

    2016-09-01

    I review recent work focussing on whether thermodynamics can be extended to nonequilibrium steady states (NESS), in particular, the possibility of consistent definitions of temperature T and chemical potential μ for NESS. The testing-grounds are simple lattice models with stochastic dynamics. Each model includes a drive that maintains the system far from equilibrium, provoking particle and/or energy flows; for zero drive the system relaxes to equilibrium. Analysis and numerical simulation show that for spatially uniform NESS, consistent definitions of T and μ are possible via coexistence with an appropriate reservoir, if (and in general only if) a particular kind of rate (that proposed by Sasa and Tasaki) is used for exchanges of particles and energy between systems. The program fails, however, for nonuniform systems. The functions T and μ describing isolated phases cannot be used to predict the properties of coexisting phases in a single, phase-separated system.

  6. 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.

  7. 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. .

  8. Coexistence of tunneling magnetoresistance and Josephson effects in SFIFS junctions

    Science.gov (United States)

    Vávra, O.; Soni, R.; Petraru, A.; Himmel, N.; Vávra, I.; Fabian, J.; Kohlstedt, H.; Strunk, Ch.

    2017-02-01

    We demonstrate an integration of tunneling magnetoresistance and the Josephson effects within one tunneling junction. Several sets of Nb-Fe-Al-Al2O3-Fe-Nb wafers with varying Al and Fe layers thickness were prepared to systematically explore the competition of TMR and Josephson effects. A coexistence of the critical current IC(dFe) and the tunneling magnetoresistance ratio T M R(dFe) is observed for iron layer dFe thickness range 1.9 and 2.9 nm. Further optimization such as thinner Al2O3 layer leads to an enhancement of the critical current and thus to an extension of the coexistence regime up to dFe≃3.9 nm Fe.

  9. Geometric constraints on phase coexistence in vanadium dioxide single crystals.

    Science.gov (United States)

    McGahan, Christina; Gamage, Sampath; Liang, Jiran; Cross, Brendan; Marvel, Robert E; Haglund, Richard F; Abate, Yohannes

    2017-02-24

    The appearance of stripe phases is a characteristic signature of strongly correlated quantum materials, and its origin in phase-changing materials has only recently been recognized as the result of the delicate balance between atomic and mesoscopic materials properties. A vanadium dioxide (VO2) single crystal is one such strongly correlated material with stripe phases. Infrared nano-imaging on low-aspect-ratio, single-crystal VO2 microbeams decorated with resonant plasmonic nanoantennas reveals a novel herringbone pattern of coexisting metallic and insulating domains intercepted and altered by ferroelastic domains, unlike previous reports on high-aspect-ratio VO2 crystals where the coexisting metal/insulator domains appear as alternating stripe phases perpendicular to the growth axis. The metallic domains nucleate below the crystal surface and grow towards the surface with increasing temperature as suggested by the near-field plasmonic response of the gold nanorod antennas.

  10. Uni-directional interaction and plant-pollinator-robber coexistence.

    Science.gov (United States)

    Wang, Yuanshi; DeAngelis, Donald L; Holland, J Nathaniel

    2012-09-01

    A mathematical model for the plant-pollinator-robber interaction is studied to understand the factors leading to the widespread occurrence and stability of such interactions. In the interaction, a flowering plant provides resource for its pollinator and the pollinator has both positive and negative effects on the plant. A nectar robber acts as a plant predator, consuming a common resource with the pollinator, but with a different functional response. Using dynamical systems theory, mechanisms of species coexistence are investigated to show how a robber could invade the plant-pollinator system and persist stably with the pollinator. In addition, circumstances are demonstrated in which the pollinator's positive and negative effects on the plant could determine the robber's invasibility and the three-species coexistence.

  11. Dynamical Scaling and Phase Coexistence in Topologically Constrained DNA Melting

    Science.gov (United States)

    Fosado, Y. A. G.; Michieletto, D.; Marenduzzo, D.

    2017-09-01

    There is a long-standing experimental observation that the melting of topologically constrained DNA, such as circular closed plasmids, is less abrupt than that of linear molecules. This finding points to an important role of topology in the physics of DNA denaturation, which is, however, poorly understood. Here, we shed light on this issue by combining large-scale Brownian dynamics simulations with an analytically solvable phenomenological Landau mean field theory. We find that the competition between melting and supercoiling leads to phase coexistence of denatured and intact phases at the single-molecule level. This coexistence occurs in a wide temperature range, thereby accounting for the broadening of the transition. Finally, our simulations show an intriguing topology-dependent scaling law governing the growth of denaturation bubbles in supercoiled plasmids, which can be understood within the proposed mean field theory.

  12. Abundance analysis of Barium stars

    Institute of Scientific and Technical Information of China (English)

    Guo-Qing Liu; Yan-Chun Liang; Li-Cai Deng

    2009-01-01

    We obtain the chemical abundances of six barium stars and two CH subgiant stars based on the high signal-to-noise ratio and high resolution Echelle spectra. The neu- tron capture process elements Y, Zr, Ba, La and Eu show obvious overabundances relative to the Sun, for example, their [Ba/Fe] values are from 0.45 to 1.27. Other elements, in- cluding Na, Mg, A1, Si, Ca, Sc, Ti, V, Cr, Mn and Ni, show comparable abundances to the Solar ones, and their [Fe/H] covers a range from -0.40 to 0.21, which means they belong to the Galactic disk. The predictions of the theoretical model of wind accretion for bi- nary systems can explain the observed abundance patterns of the neutron capture process elements in these stars, which means that their overabundant heavy-elements could be caused by accreting the ejecta of AGB stars, the progenitors of present-day white dwarf companions in binary systems.

  13. 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.

  14. Coexistence of diploid, triploid and tetraploid crucian carp (Carassius auratus in natural waters

    Directory of Open Access Journals (Sweden)

    You Cuiping

    2011-01-01

    Full Text Available Abstract Background Crucian carp (abbreviated CC belongs to the genus of Carassius within the family of Cyprinidae. It has been one of the most important freshwater species for Chinese aquaculture and is especially abundant in the Dongting water system of Hunan province. CC used to be considered as all diploid forms. However, coexistence of diploid (abbreviated 2nCC, triploid (abbreviated 3nCC and tetraploid crucian carp (abbreviated 4nCC population of the Dongting water system was first found by our recently researches. Results We examined the ploidy level and compared biological characteristics in different ploidy CC. In reproductive mode, 2nCC was bisexual generative and 4nCC generated all-female offspring by gynogenesis. However, 3nCC generated progenies in two different ways. 3nCC produced bisexual triploid offspring fertilized with 3nCC spermatozoa, while it produced all-female triploid offspring by gynogenesis when its ova were activated by heterogenous spermatozoa. The complete mitochondrial DNA of three different ploidy fishes was sequenced and analyzed, suggesting no significant differences. Interestingly, microchromosomes were found only in 3nCC, which were concluded to be the result of hybridization. Allogenetic DNA fragments of Sox genes were obtained in 3nCC and 4nCC, which were absent in 2nCC. Phylogenetics analysis based on Sox4 gene indicated 3nCC and 4nCC formed a separate group from 2nCC. Conclusions In summary, this is the first report of the co-existence of three types of different ploidy crucian carps in natural waters in China. It was proved that the coexistence of different ploidy CC was reproductively maintained. We further hypothesized that 3nCC and 4nCC were allopolyploids that resulted from hybridization. The different ploidy CC population we obtained in this study possesses great significance for the study of polyploidization and the evolution of vertebrates.

  15. Coexistence analysis of diploid and triploid hybrid water frogs

    Science.gov (United States)

    Apri, M.; Suandi, D.; Soewono, E.

    2014-02-01

    A dynamical model for genotype distributions of all hybrid populations of Pelophylax esculentus in the absence of differential survival is studied here. Assuming that under natural condition the parental genotypes LL and RR do not survive into adult stage, the dynamic is then reduced into three-dimensional dynamical system of classes LR, LLR, LRR genotypes. Coexistence of diploid (LR) and triploid (LLR and LRR) genotypes is analyzed here.

  16. Coexistence of gastrointestinal stromal tumor, esophageal and gastric cardia carcinomas

    OpenAIRE

    Zhou, Yong; Wu, Xu-Dong; Shi, Quan; Jia, Jing

    2013-01-01

    Gastric gastrointestinal stromal tumor (GIST), esophageal squamous cell carcinoma and gastric cardia adenocarcinoma are distinct neoplasms originating from different cell layers; therefore, simultaneous development of such carcinomas is relatively rare. Auxiliary examinations revealed coexistence of esophageal and gastric cardia carcinoma with lymph node metastasis in a 77-year-old man. Intraoperatively, an extraluminal tumor (about 6.0 cm × 5.0 cm × 6.0 cm) at the posterior wall of the gastr...

  17. Algebraic benchmark for prolate-oblate coexistence in nuclei

    CERN Document Server

    Leviatan, A

    2016-01-01

    We present a symmetry-based approach for prolate-oblate and spherical-prolate-oblate shape coexistence, in the framework of the interacting boson model of nuclei. The proposed Hamiltonian conserves the SU(3) and $\\overline{\\rm SU(3)}$ symmetry for the prolate and oblate ground bands and the U(5) symmetry for selected spherical states. Analytic expressions for quadrupole moments and $E2$ rates involving these states are derived and isomeric states are identified by means of selection rules.

  18. What constitutes a convention? : implications for the coexistence of conventions

    OpenAIRE

    Kolstad, Ivar

    2002-01-01

    A model of repeated play of a coordination game, where stage games have a location in social space, and players receive noisy signals of the true location of their games, is reviewed. Sugden (1995) suggests that in such a model, there can be a stationary state of convention coexistence only if interaction is non-uniform across social space. This paper shows that an alternative definition of conventions, which links conventions to actions rather than expectations, permits convention coexistenc...

  19. Ichthyosis Vulgaris Coexisted with Acrokeratosis Verruciformis: A Case Report

    Directory of Open Access Journals (Sweden)

    Gamze Serarslan

    2008-12-01

    Full Text Available Ichthyosis vulgaris is an autosomal dominant inherited, keratinization disorder and characterized by diffuse scaling. Acrokeratosis verruciformis is also an autosomal dominant, rare keratinization disorder and characterized by warty, brownish to skin colored papules on the dorsa of the hands and feet. We present a case of ichthyosis vulgaris coexisted with acrokeratosis verruciformis in a 24-year-old woman. (Turkderm 2008; 42: 134-6

  20. Aspergilloma coexisting with idiopathic pulmonary fibrosis: A rare occurrence

    Directory of Open Access Journals (Sweden)

    N Kumar

    2013-01-01

    Full Text Available Fungal ball (mycetoma/aspergilloma is a saprophytic fungal infection that colonizes pre-existing lung cavities. Reported literature suggests its development in cystic lesions/cavitation associated with tuberculosis, sarcoidosis, bronchiectasis, lung abscess, and cavitating neoplasm to name a few. Coexistence of aspergilloma with idiopathic pulmonary fibrosis (IPF has not been reported in literature so far, to the best of our knowledge. We hereby report the case of a 55-year-old female with IPF having fungal ball.

  1. The coexistence of controlling and other management methods

    OpenAIRE

    Agnieszka Bienkowska; Anna Zgrzywa-Ziemak

    2014-01-01

    The aim of the article was the analysis of the relations of the coexistence of Controlling and other management methods (Benchmarking, BPM, BPR, BSC, Competency-based Management, CRM, ERP, KM, LM, Outsourcing, Six Sigma, TQM). The complexity and dynamics of modern management systems in fact determine the simultaneous and sequential application of many concepts and methods of management. Controlling is a comprehensive method of interdisciplinary character which is the integrating plane for man...

  2. Auditory-olfactory synesthesia coexisting with auditory-visual synesthesia.

    Science.gov (United States)

    Jackson, Thomas E; Sandramouli, Soupramanien

    2012-09-01

    Synesthesia is an unusual condition in which stimulation of one sensory modality causes an experience in another sensory modality or when a sensation in one sensory modality causes another sensation within the same modality. We describe a previously unreported association of auditory-olfactory synesthesia coexisting with auditory-visual synesthesia. Given that many types of synesthesias involve vision, it is important that the clinician provide these patients with the necessary information and support that is available.

  3. Parental harsh discipline in mainland China: prevalence, frequency, and coexistence.

    Science.gov (United States)

    Wang, Meifang; Liu, Li

    2014-06-01

    The study examined the prevalence, frequency, and coexistence of psychological aggression (PA), corporal punishment (CP), and severe physical abuse (SPA) in mainland China. Using a sample of 2,518 father-mother dyads of 3-15-year-old children, the findings revealed that parental harsh discipline was prevalent in mainland China. The rates of harsh discipline in the current study fell in the middle of the ranges of rates found in other studies. Harsh discipline was most likely directed at boys or children aged 7 years and committed by mothers, young fathers, or high and low socioeconomic status (SES) parents. The prevalence of maternal and paternal PA and CP declined with the children's age. Maternal and paternal SPA first increased and then decreased with child age. The frequency of the three types of maternal and paternal harsh discipline fluctuated depending on the age of the children. In addition, approximately 50% of the mothers and fathers who reported using severe forms of disciplinary practices also engaged in less severe forms of harsh disciplinary practices against their children. SPA generally coexisted with CP and PA, and CP was usually accompanied by PA; however, PA was more likely to occur independently compared with CP and SPA. Moreover, maternal harsh discipline coexisted with paternal harsh discipline to some extent. The coexistence decreased with increasing severity of parental harsh discipline and differed according to child gender. These findings highlight the importance of studying these three types of parental harsh discipline simultaneously and intervening in harsh discipline by mothers and fathers within the same family.

  4. Inherent Shear-Dilatation Coexistence in Metallic Glass

    Institute of Scientific and Technical Information of China (English)

    JIANG Min-Qiang; JIANG Si-Yue; DAI Lan-Hong

    2009-01-01

    Shear deformation can induce normal stress or hydrostatic stress in metallic glasses [Nature Mater. 2 (2003) 449, Intermetallics 14 (2006) 1033]. We perform the bulk deformation of three-dimensional Cu46Zr54 metallic glass (MG) and Cu single crystal model systems using molecular dynamics simulation. The results indicate that hydrostatic stress can incur shear stress in MG, but not in crystal. The resultant pronounced asymmetry between tension and compression originates from this inherent shear-dilatation coexistence in MG.

  5. How do Conflicting Theories about Financial Markets Coexist?

    OpenAIRE

    Wesley Phoa; Sergio Focardi; Frank Fabozzi

    2006-01-01

    There are many conflicting interpretations of security prices and price determination in financial markets. They range from academic theories based on efficient markets and rational expectations hypotheses, to more traditional methods of fundamental analysis, to theories of "value" and "growth" investing, to chart-reading and technical analysis, to notions such as "reflexivity." These interpretations are logically inconsistent with each other, but they seem to co-exist, sometimes even on the ...

  6. Acyl chain composition and coexisting fluid phases in lipid bilayers

    Science.gov (United States)

    Gu, Yongwen; Bradley, Miranda; Mitchell, Drake

    2011-10-01

    At room temperature phospholipid bilayers enriched in sphingolipids and cholesterol may form a solid phase as well as two coexisting fluid phases. These are the standard fluid phase, or the liquid-disordered phase, ld, and the liquid-ordered phase, lo, which is commonly associated with lipid rafts. Ternary mixtures of palmitoyl-oleoyl-phosphocholine (POPC; 16:0,18:1 PC), sphingomyelin (SPM), and cholesterol (Chol) form coexisting lo, ld and solid phases over a wide range of molar ratios. We are examining the ability of two fluorescent probes to detect these 2 phases: NBD linked to di-16:0 PE which partitions strongly into the lo phase and NBD linked to di-18:1 PE which partitions strongly into the ld phase. We are also examining the effect of the highly polyunsaturated phospholipid stearoyl-docosahexanoyl-phosphocholine (SDPC; 18:0, 22:6 PC) on the ternary phase diagram of POPC/SPM/Chol with particular focus on the functionally important lo/ld coexistence region. We report on the fluorescence lifetime and anisotropy decay dynamics of these two fluorescent probes.

  7. Mechanisms for stable coexistence in an insect community.

    Science.gov (United States)

    Fan, Meng; Zhang, Bingbing; Li, Michael Yi

    2010-07-01

    In this paper, we formulate a three-species ecological community model consisting of two aphid species (Acyrthosiphon pisum and Megoura viciae) and a specialist parasitoid (Aphidius ervi) that attacks only one of the aphids (A pisum). The model incorporates both density-mediated and trait-mediated host-parasitoid interactions. Our analysis shows that the model possesses much richer and more realistic dynamics than earlier models. Our theoretical results reveal a new mechanism for stable coexistence in a three-species community in which any two species alone do not co-exist. More specifically, it is known that, when a predator is introduced into a community of two competing species, if the predator only predates on the strong competitor, it can allow the weak competitor to survive, but may drive the strong competitor to extinction through over-exploitation. We show that if the weak competitor interferes the predation on the strong competitor through trait-mediated indirect effects, then all three species can stably co-exist.

  8. Dynamical phase coexistence: A simple solution to the "savanna problem"

    CERN Document Server

    Vazquez, F; Calabrese, J M; Munoz, M A; 10.1016/j.jtbi.2010.02.011

    2010-01-01

    We introduce the concept of 'dynamical phase coexistence' to provide a simple solution for a long-standing problem in theoretical ecology, the so-called "savanna problem". The challenge is to understand why in savanna ecosystems trees and grasses coexist in a robust way with large spatio-temporal variability. We propose a simple model, a variant of the Contact Process (CP), which includes two key extra features: varying external (environmental/rainfall) conditions and tree age. The system fluctuates locally between a woodland and a grassland phase, corresponding to the active and absorbing phases of the underlying pure contact process. This leads to a highly variable stable phase characterized by patches of the woodland and grassland phases coexisting dynamically. We show that the mean time to tree extinction under this model increases as a power-law of system size and can be of the order of 10,000,000 years in even moderately sized savannas. Finally, we demonstrate that while local interactions among trees m...

  9. Coexistence of charge and ferromagnetic order in fcc Fe.

    Science.gov (United States)

    Hsu, Pin-Jui; Kügel, Jens; Kemmer, Jeannette; Parisen Toldin, Francesco; Mauerer, Tobias; Vogt, Matthias; Assaad, Fakher; Bode, Matthias

    2016-03-14

    Phase coexistence phenomena have been intensively studied in strongly correlated materials where several ordered states simultaneously occur or compete. Material properties critically depend on external parameters and boundary conditions, where tiny changes result in qualitatively different ground states. However, up to date, phase coexistence phenomena have exclusively been reported for complex compounds composed of multiple elements. Here we show that charge- and magnetically ordered states coexist in double-layer Fe/Rh(001). Scanning tunnelling microscopy and spectroscopy measurements reveal periodic charge-order stripes below a temperature of 130 K. Close to liquid helium temperature, they are superimposed by ferromagnetic domains as observed by spin-polarized scanning tunnelling microscopy. Temperature-dependent measurements reveal a pronounced cross-talk between charge and spin order at the ferromagnetic ordering temperature about 70 K, which is successfully modelled within an effective Ginzburg-Landau ansatz including sixth-order terms. Our results show that subtle balance between structural modifications can lead to competing ordering phenomena.

  10. 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.

  11. Direct determination of liquid phase coexistence by Monte Carlo simulations.

    Science.gov (United States)

    Zweistra, Henk J A; Besseling, N A M

    2006-07-01

    A formalism to determine coexistence points by means of Monte Carlo simulations is presented. The general idea of the method is to perform a simulation simultaneously in several unconnected boxes which can exchange particles. At equilibrium, most of the boxes will be occupied by a homogeneous phase. The compositions of these boxes yield coexisting points on the binodal. However, since the overall composition is fixed, at least one of the boxes will contain an interface. We show that this does not affect the results, provided that the interface has no net curvature. We coin the name "Helmholtz-ensemble method," because the method is related to the well-known Gibbs-ensemble method, but the volume of the boxes is constant. Since the box volumes are constant, we expect that this method will be particularly useful for lattice models. The accuracy of the Helmholtz-ensemble method is benchmarked against known coexistence curves of the three-dimensional Ising model with excellent results.

  12. Generic phase coexistence in the totally asymmetric kinetic Ising model

    Science.gov (United States)

    Godrèche, Claude; Luck, Jean-Marc

    2017-07-01

    The physical analysis of generic phase coexistence in the North-East-Center Toom model was originally given by Bennett and Grinstein. The gist of their argument relies on the dynamics of interfaces and droplets. We revisit the same question for a specific totally asymmetric kinetic Ising model on the square lattice. This nonequilibrium model possesses the remarkable property that its stationary-state measure in the absence of a magnetic field coincides with that of the usual ferromagnetic Ising model. We use both analytical arguments and numerical simulations in order to make progress in the quantitative understanding of the phenomenon of generic phase coexistence. At zero temperature a mapping onto the TASEP allows an exact determination of the time-dependent shape of the ballistic interface sweeping a large square minority droplet of up or down spins. At finite temperature, measuring the mean lifetime of such a droplet allows an accurate measurement of its shrinking velocity v, which depends on temperature T and magnetic field h. In the absence of a magnetic field, v vanishes with an exponent Δ_v≈2.5+/-0.2 as the critical temperature T c is approached. At fixed temperature in the ordered phase, v vanishes at the phase-boundary fields +/- h_b(T) which mark the limits of the coexistence region. The latter fields vanish with an exponent Δ_h≈3.2+/-0.3 as T c is approached.

  13. Coexistence of intracranial epidermoid tumor and multiple cerebral aneurysms

    Science.gov (United States)

    Yao, Pei-Sen; Lin, Zhang-Ya; Zheng, Shu-Fa; Lin, Yuan-Xiang; Yu, Liang-Hong; Jiang, Chang-Zhen; Kang, De-Zhi

    2017-01-01

    Abstract Rationale: There were a few case reports concerning epidermoid tumor coexisted with multiple cerebral aneurysms. Here, we present one case of coexistence of intracranial epidermoid tumor and multiple cerebral aneurysms and performed a literature review. Patient concerns: A 42 years old male patient was admitted to our institution with complaints of headache and dizziness. Interventions: The radiological examinations showed a hypointense lesion in the right parasellar and petrous apex region and an ipsilateral saccular aneurysm originated from the M2–M3 junction of the right middle cerebral artery (MCA) and a saccular aneurysm of the clinoid segment of right internal carotid artery (ICA). Interventions: The patients underwent a right frontotemporal approach for removal of the epidermoid tumor and clipping of the MCA aneurysm in one stage. The aneurysm located at the clinoid segment of ICA was invisible and untreated during operation. Outcomes: No postoperative complications were found in the patient. The patient's follow up after 5 years of surgical treatment was uneventful, and the untreated aneurysm remains stable. Lessons: The coexistence of intracranial epidermoid tumor and cerebral aneurysm is a rare event. The secondly inflammation in cerebral arterial wall may be responsible for the aneurysm formation. Surgical treatment of the intracranial epidermoid tumor and cerebral aneurysm repair may be an optimal scheme in one stage. PMID:28151901

  14. 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. 

  15. Magnetic phase coexistence in CMR manganites: ESR evidence

    Energy Technology Data Exchange (ETDEWEB)

    Ccahuana, D. Laura [Instituto Balseiro, Universidad Nacional de Cuyo and Comision Nacional de Energia Atomica and Centro Atomico Bariloche, Comision Nacional de Eenrgia Atomica. Av. Ezequiel Bustillo 9500, 8400 San Carlos de Bariloche, Rio Negro (Argentina)]. E-mail: ccahuana@cab.cnea.gov.ar; Winkler, E. [Instituto Balseiro, Universidad Nacional de Cuyo and Comision Nacional de Energia Atomica and Centro Atomico Bariloche, Comision Nacional de Eenrgia Atomica. Av. Ezequiel Bustillo 9500, 8400 San Carlos de Bariloche, Rio Negro (Argentina); Prado, F. [Instituto Balseiro, Universidad Nacional de Cuyo and Comision Nacional de Energia Atomica and Centro Atomico Bariloche, Comision Nacional de Eenrgia Atomica. Av. Ezequiel Bustillo 9500, 8400 San Carlos de Bariloche, Rio Negro (Argentina); Butera, A. [Instituto Balseiro, Universidad Nacional de Cuyo and Comision Nacional de Energia Atomica and Centro Atomico Bariloche, Comision Nacional de Eenrgia Atomica. Av. Ezequiel Bustillo 9500, 8400 San Carlos de Bariloche, Rio Negro (Argentina); Ramos, C.A. [Instituto Balseiro, Universidad Nacional de Cuyo and Comision Nacional de Energia Atomica and Centro Atomico Bariloche, Comision Nacional de Eenrgia Atomica. Av. Ezequiel Bustillo 9500, 8400 San Carlos de Bariloche, Rio Negro (Argentina); Causa, M.T. [Instituto Balseiro, Universidad Nacional de Cuyo and Comision Nacional de Energia Atomica and Centro Atomico Bariloche, Comision Nacional de Eenrgia Atomica. Av. Ezequiel Bustillo 9500, 8400 San Carlos de Bariloche, Rio Negro (Argentina); Tovar, M. [Instituto Balseiro, Universidad Nacional de Cuyo and Comision Nacional de Energia Atomica and Centro Atomico Bariloche, Comision Nacional de Eenrgia Atomica. Av. Ezequiel Bustillo 9500, 8400 San Carlos de Bariloche, Rio Negro (Argentina)

    2004-12-31

    The coexistence of magnetic phases in colossal magnetoresistant (CMR) manganites is characteristic of this family of compounds. We studied this phenomenon in a hole doped sample of La{sub 0.75}Ca{sub 0.25}MnO{sub 3} by means of magnetization measurements and electron spin resonance (ESR) technique. The magnetic transition at T{sub c}=220 K was determined as the maximum slope in the M(T) curve. Above 250 K the ESR spectrum consists of a single lorentzian line centered at g=1.99(1). The ESR resonance splits below 250 K and a second resonance, of FM character, is present with a T dependent resonance field (H{sub r}). When T decreases, H{sub r} diminishes for the FM line while the PM line remains essentially centered at a constant H{sub r}. At the same time, a continuous transference of intensity takes place, from the PM line to the FM one. We observed the coexistence of both, PM and FM lines, down to 220 K. In this extended range of coexistence (250-220 K) the magnetization shows also a peculiar behavior.

  16. Spatial coexistence of synchronized oscillation and death: A chimeralike state

    Science.gov (United States)

    Dutta, Partha Sharathi; Banerjee, Tanmoy

    2015-10-01

    We report an interesting spatiotemporal state, namely the chimeralike incongruous coexistence of synchronized oscillation and stable steady state (CSOD) in a network of nonlocally coupled oscillators. Unlike the chimera and chimera death state, in the CSOD state identical oscillators are self-organized into two coexisting spatially separated domains: In one domain neighboring oscillators show synchronized oscillation and in another domain the neighboring oscillators randomly populate either a synchronized oscillating state or a stable steady state (we call it a death state). We consider a realistic ecological network and show that the interplay of nonlocality and coupling strength results in two routes to the CSOD state: One is from a coexisting mixed state of amplitude chimera and death, and another one is from a globally synchronized state. We provide a qualitative explanation of the origin of this state. We further explore the importance of this study in ecology that gives insight into the relationship between spatial synchrony and global extinction of species. We believe this study will improve our understanding of chimera and chimeralike states.

  17. Periodic coexistence of four species competing for three essential resources.

    Science.gov (United States)

    Li, Bingtuan; Smith, Hal L

    2003-08-01

    We show the existence of a periodic solution in which four species coexist in competition for three essential resources in the standard model of resource competition. By assuming that species i is limited by resource i for each i near the positive equilibrium, and that the matrix of contents of resources in species is a combination of cyclic matrix and a symmetric matrix, we obtain an asymptotically stable periodic solution of three species on three resources via Hopf bifurcation. A simple bifurcation argument is then employed which allows us to add a fourth species. In principle, the argument can be continued to obtain a periodic solution adding one new species at a time so long as asymptotic stability can be assured at each step. Numerical simulations are provided to illustrate our analytical results. The results of this paper suggest that competition can generate coexistence of species in the form of periodic cycles, and that the number of coexisting species can exceed the number of resources in a constant and homogeneous environment.

  18. Niche partitioning and species coexistence in a Neotropical felid assemblage

    Science.gov (United States)

    Di Bitetti, Mario S.; De Angelo, Carlos D.; Di Blanco, Yamil E.; Paviolo, Agustín

    2010-07-01

    Carnivores have been used as a model to understand the effects of competition in community structure. Behavioral mechanisms that facilitate species coexistence have been poorly explored and may explain the lack of community-wide morphological character displacement in some carnivore assemblages. We use the results of large-scale and intensive camera-trap surveys conducted in the Atlantic Forest of NE Argentina between 2003 and 2008 to describe the spatial patterns of detection and the daily pattern of records of the six wild cat species present in the region (jaguar Panthera onca, puma Puma concolor, ocelot Leopardus pardalis, jaguarundi Puma yagouaroundi, margay Leopardus wiedii, and oncilla Leopardus tigrinus). We use these patterns to generate hypotheses about behavioral differences that may facilitate species coexistence. The larger species were more frequently recorded in the better-protected areas, probably as a result of anthropogenic effects (poaching of cats and their prey). Competitive release from ocelots and jaguarundis may explain why the oncilla and the margay showed the opposite pattern. Morphologically similar species had the most contrasting activity patterns: the margay was exclusively nocturnal and the jaguarundi diurnal. The other species were cathemeral, but alternated their peaks of activity in relation to the relative order of their body weights. The contrasting temporal patterns observed and the ability of pumas and oncillas to adjust their activity patterns to local conditions may facilitate the coexistence of these cat species and explain the lack of character displacement in this assemblage.

  19. Resource abundance and the critical transition to cooperation.

    Science.gov (United States)

    Connelly, B D; Bruger, E L; McKinley, P K; Waters, C M

    2016-12-30

    Cooperation is abundant in nature, occurring at all levels of biological complexity. Yet cooperation is continually threatened by subversion from noncooperating cheaters. Previous studies have shown that cooperation can nevertheless be maintained when the benefits that cooperation provides to relatives outweigh the associated costs. These fitness costs and benefits are not fixed properties, but can be affected by the environment in which populations reside. Here, we describe how one environmental factor, resource abundance, decisively affects the evolution of cooperative public goods production in two independent evolving systems. In the Avida digital evolution platform, populations evolved in environments with different levels of a required resource, whereas populations of Vibrio cholerae evolved in the presence of different nutrient concentrations. In both systems, cooperators and cheaters co-existed stably in resource-rich environments, whereas cheaters dominated in resource-poor environments. These two outcomes were separated by a sharp transition that occurred at a critical level of resource. These results offer new insights into how the environment affects the evolution of cooperation and highlight the challenges that populations of cooperators face when they experience environmental change.

  20. An experimental study of tin partition between melt and aqueous fluid in F/CI-coexisting magma

    Institute of Scientific and Technical Information of China (English)

    HU XiaoYan; BI XianWu; SHANG LinBo; HU RuiZhong; CAI GuoSheng; CHEN YouWei

    2009-01-01

    In order to investigate the formation mechanism of tin ores associated with F-bearing granite, an experimental study of tin partition between F-bearing granitic melt and coexisting HCI-bearing aqueous fluid was conducted at 850"C and 100MPa with fo2 approaching NNO. Geochemical behavior of tin was traced by changes in starting solid materials with different alumina saturation index ASl, in F content and in starting fluids of various HCl concentrations. The results show that DSn increases with ASl of melt and peraluminous melt is favorable for tin partition into aqueous fluid in the F/Cl-coexisting system. Aqueous fluid of higher HCl concentrations is advantageous for enrichment of tin. Furthermore,chlorine contents in glass run products correlate positively with F and CI contents in the magma. In the F/Cl-coexisting system, granitic melts with high F contents (>~-1 wt%) could extract and enrich tin in the melt which can serve as a reservoir for the formation of tin ores. However, the partition coefficient of tin would increase significantly when F contents in the melt were below 1 wt%. Therefore, the decrease of F contents is favorable to the partition of tin into aqueous fluid with high HCI contents, thus promoting deposition of hydrothermal tin ores.

  1. 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.

  2. Co-existence of porokeratosis variants concurrent with Bowen's disease: two rare cases report.

    Science.gov (United States)

    Korviriyakamol, Tarinee; Kattipathananpong, Pinnaree; Chunhasewee, Chakkrapong; Wessagowit, Vesarat; Kootiratrakarn, Tanawatt

    2014-03-01

    Coexisting variants of porokeratosis rarely occurs. Disseminated superficial porokeratosis (DSP) is characterized by multiple uniform small annular papules distributed all over body. DSP commonly coexist with linear porokeratosis (LP), but it is uncommon for DSP to coexist with porokeratosis of Mibelli (PM). PM presents with central atrophic erythematous plaques and thread-like elevated border. It occurs mainly on extremities. Although malignant transformation can be found in the porokeratosis, there is still no report case of coexisting variants of porokeratosis concurrent with Bowen's disease. The clinical and histopathologic finding of rare coexisting variants of porokeratosis (PM and DSP) concurrent with squamous dysplasia is described.

  3. Lead abundance in the uranium star CS 31082-001

    DEFF Research Database (Denmark)

    Plez, B.; Hill, V.; Cayrel, R.

    2004-01-01

    stars:abundances- physical data and processes: nuclear reactions, nucleosynthesis, abundances- atomic data......stars:abundances- physical data and processes: nuclear reactions, nucleosynthesis, abundances- atomic data...

  4. Regulating coexistence of GM and non-GM crops without jeopardizing economic incentives.

    Science.gov (United States)

    Demont, Matty; Devos, Yann

    2008-07-01

    The ongoing debate about the coexistence of genetically modified (GM) and non-GM crops in the European Union (EU) mainly focuses on preventive measures needed to keep the adventitious presence of GM material in non-GM products below established tolerance thresholds, as well as on issues covering questions of liability and the duty to redress the incurred economic harm once adventitious mixing in non-GM products has occurred. By contrast, the interplay between the economic incentives and costs of coexistence has attracted little attention. The current overemphasis on the technical aspects and cost of coexistence over its economic incentives might lead EU policy-makers to adopt too stringent and rigid regulations on coexistence. Therefore, we argue for flexible coexistence regulations that explicitly take into account the economic incentives for coexistence. Our arguments provide a timely and important framework for EU policy-makers, who are currently struggling to implement coherent coexistence regulations in all member states.

  5. Surface abundances of ON stars

    CERN Document Server

    Martins, F; Palacios, A; Howarth, I; Georgy, C; Walborn, N R; Bouret, J -C; Barba, R

    2015-01-01

    Massive stars burn hydrogen through the CNO cycle during most of their evolution. When mixing is efficient, or when mass transfer in binary systems happens, chemically processed material is observed at the surface of O and B stars. ON stars show stronger lines of nitrogen than morphologically normal counterparts. Whether this corresponds to the presence of material processed through the CNO cycle or not is not known. Our goal is to answer this question. We perform a spectroscopic analysis of a sample of ON stars with atmosphere models. We determine the fundamental parameters as well as the He, C, N, and O surface abundances. We also measure the projected rotational velocities. We compare the properties of the ON stars to those of normal O stars. We show that ON stars are usually helium-rich. Their CNO surface abundances are fully consistent with predictions of nucleosynthesis. ON stars are more chemically evolved and rotate - on average - faster than normal O stars. Evolutionary models including rotation cann...

  6. Zooplankton abundance in subtropical waters: is there a lunar cycle?

    Directory of Open Access Journals (Sweden)

    Santiago Hernández-León

    2001-07-01

    Full Text Available Based on historical data of abundance, we report evidence of changes in zooplankton abundance in the 0-200 m layer related to the moon cycle confirming that this phenomenon is produced in the marine environment, similarly to the one described for freshwater ecosystems. A clear decrease in the abundance of copepodites plus copepods was observed from the second to the fourth quarter of the moon when the seasonal variability was suppressed. During the full moon phase the large zooplankton and micronekton of the deep scattering layers (DSL would not reach the upper mixed layer in order to avoid predation because of the relatively high level of illumination. Thus epipelagic zooplankton abundance increases as the effect of a lower predatory pressure. Conversely, during the new moon phase the diel migrants reach the surface waters and epiplankton abundance considerably decreases. Recent oceanic sediment trap data in subtropical waters indicate that the particle flux increases at about 30 days period. Thus, the effect of diel vertical migrants could promote not only the variability in their resources and the intensity of the active flux, but could also drive the variability in the gravitational flux.

  7. Co-existence of functionally different vesicular neurotransmitter transporters

    Directory of Open Access Journals (Sweden)

    Agnieszka eMünster-Wandowski

    2016-02-01

    Full Text Available The vesicular transmitter transporters VGLUT, VGAT, VMAT2 and VAChT, define phenotype and physiological properties of neuronal subtypes. VGLUTs concentrate the excitatory amino acid glutamate, VGAT the inhibitory amino acid GABA, VMAT2 monoamines, and VAChT acetylcholine into synaptic vesicle (SV. Following membrane depolarization SV release their content into the synaptic cleft. A strict segregation of vesicular transporters is mandatory for the precise functioning of synaptic communication and of neuronal circuits. In the last years, evidence accumulates that subsets of neurons express more than one of these transporters leading to synaptic co-release of different and functionally opposing transmitters and modulation of synaptic plasticity. Synaptic co-existence of transporters may change during pathological scenarios in order to ameliorate misbalances in neuronal activity. In addition, evidence increases that transporters also co-exist on the same vesicle providing another layer of regulation. Generally, vesicular transmitter loading relies on an electrochemical gradient µH+ driven by the proton ATPase rendering the lumen of the vesicle with respect to the cytosol positive ( and acidic (pH. While the activity of VGLUT mainly depends on the component, VMAT, VGAT and VAChT work best at a high pH. Thus, a vesicular synergy of transporters depending on the combination may increase or decrease the filling of SV with the principal transmitter. We provide an overview on synaptic co-existence of vesicular transmitter transporters including changes in the excitatory/inhibitory balance under pathological conditions. Additionally, we discuss functional aspects of vesicular synergy of transmitter transporters.

  8. Co-existence of Functionally Different Vesicular Neurotransmitter Transporters.

    Science.gov (United States)

    Münster-Wandowski, Agnieszka; Zander, Johannes-Friedrich; Richter, Karin; Ahnert-Hilger, Gudrun

    2016-01-01

    The vesicular transmitter transporters VGLUT, VGAT, VMAT2 and VAChT, define phenotype and physiological properties of neuronal subtypes. VGLUTs concentrate the excitatory amino acid glutamate, VGAT the inhibitory amino acid GABA, VMAT2 monoamines, and VAChT acetylcholine (ACh) into synaptic vesicle (SV). Following membrane depolarization SV release their content into the synaptic cleft. A strict segregation of vesicular transporters is mandatory for the precise functioning of synaptic communication and of neuronal circuits. In the last years, evidence accumulates that subsets of neurons express more than one of these transporters leading to synaptic co-release of different and functionally opposing transmitters and modulation of synaptic plasticity. Synaptic co-existence of transporters may change during pathological scenarios in order to ameliorate misbalances in neuronal activity. In addition, evidence increases that transporters also co-exist on the same vesicle providing another layer of regulation. Generally, vesicular transmitter loading relies on an electrochemical gradient ΔμH(+) driven by the proton ATPase rendering the lumen of the vesicle with respect to the cytosol positive (Δψ) and acidic (ΔpH). While the activity of VGLUT mainly depends on the Δψ component, VMAT, VGAT and VAChT work best at a high ΔpH. Thus, a vesicular synergy of transporters depending on the combination may increase or decrease the filling of SV with the principal transmitter. We provide an overview on synaptic co-existence of vesicular transmitter transporters including changes in the excitatory/inhibitory balance under pathological conditions. Additionally, we discuss functional aspects of vesicular synergy of transmitter transporters.

  9. 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

  10. Electrical signaling and photosynthesis: can they co-exist together?

    Science.gov (United States)

    Pavlovič, Andrej; Mancuso, Stefano

    2011-06-01

    Mechanical irritation of trigger hairs and subsequent generation of action potentials have significant impact on photosynthesis and respiration in carnivorous Venus flytrap (Dionaea muscipula). Action potential-mediated inhibition of photosynthesis and stimulation of respiration is confined only to the trap and was not recorded in adjacent photosynthetic lamina. We showed that the main primary target of electrical signals on assimilation is in the dark enzymatic reaction of photosynthesis. Without doubt, the electrical signaling is costly, and the possible co-existence of such type of signals and photosynthesis in plant cell is discussed.

  11. Myasthenia gravis and thymoma coexisting with myotonic dystrophy type 1.

    Science.gov (United States)

    Ekmekci, Ozgul; Karasoy, Hatice; Bademkiran, Fikret; Akkus, Dilek Evyapan; Yuceyar, Nur

    2014-01-01

    We describe a 34-year old man presenting with subacute generalized myasthenic symptoms. His clinical features and laboratory investigations demonstrated both myasthenia gravis and myotonic dystrophy type 1. The computerized tomography of chest revealed anterior mediastinal mass. The lymphocyte-rich thymoma was removed surgically and he received radiotherapy. Recent observations suggested that the patients with myotonic dystrophy may have an increased risk of benign and malignant tumours but its coexistence with thymoma is very rare. The risk of thymoma associated with myotonic dystrophy is unknown.

  12. 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.

  13. Collective coordinates, shape transitions and shape coexistence a microscopic approach

    CERN Document Server

    Nakatsukasa, T; Nakatsukasa, Takashi; Walet, Niels R.

    1998-01-01

    We investigate a description of shape-mixing and shape-transitions using collective coordinates. To that end we apply a theory of adiabatic large-amplitude motion to a simplified nuclear shell-model, where the approximate results can be contrasted with exact diagonalisations. We find excellent agreement for different regimes, and contrast the results with those from a more standard calculation using a quadrupole constraint. We show that the method employed in this work selects diabatic (crossing) potential energy curves where these are appropriate, and discuss the implications for a microscopic study of shape coexistence.

  14. Coexistence facilitates interspecific biofilm formation in complex microbial communities

    DEFF Research Database (Denmark)

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

    2016-01-01

    , 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......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...

  15. Prolate and Oblate Shape Coexistence in 188Pt

    Institute of Scientific and Technical Information of China (English)

    LIU Yuan; A.Osa; Y.Hatsukawa; SUN Yang; ZHOU Xiao-Hong; ZHANG Yu-Hu; ZHENG-Yong; LIU Min-Liang; GUO Ying-Xiang; M.Oshima; Y.Toh; M.Koizumi

    2008-01-01

    A standard in-beam γ-spectroscopy experiment for 188Pt is performed via the 176Yb(18O,6n) reaction at beam energies of 88 and 95 Me V,and the level scheme for 188 Pt is established.Prolate and oblate shape coexistence has been demonstrated to occur in 188Pt by applying the projected shell model.The rotation alignment of i13/2neutrons drives the yrast sequence changing suddenly from prolate to oblate shape at angular momentum 10h,indicating likely a new type of shape phase transition along the yrast fine in 188Pt.

  16. Takotsubo Cardiomyopathy Coexisting with Acute Pericarditis and Myocardial Bridge

    Science.gov (United States)

    Sezavar, Seyed Hashem; Riahi Beni, Hassan; Ghanavati, Reza; Hajahmadi, Marjan

    2016-01-01

    Takotsubo cardiomyopathy (TCM) is a stress-induced cardiomyopathy that occurs primarily in postmenopausal women. It mimics clinical picture of acute coronary syndrome with nonobstructive coronary arteries and a characteristic transient left (or bi-) ventricular apical ballooning at angiography. The exact pathogenesis of TCM is not well recognized. Hereby we present an unusual case of TCM that presents with signs and symptoms of acute pericarditis and was also found to have a coexisting coronary muscle bridge on coronary angiography. We discuss the impact of these associations in better understanding of the pathogenesis of TCM. PMID:27437150

  17. Performance Analysis on the Coexistence of Multiple Cognitive Radio Networks

    Science.gov (United States)

    2015-05-28

    Conference on Network Protocols , Kyoto , Japan, pp. 305-314, Oct 2010. [4] W. Yuan, X. Wang, and J.-P. Linnartz, "A coexistence model of ieee 802.15.4...such as security requirements. Since CSMA/CA is a well-established Media Access Control (MAC) protocol and has been adopted by many practical wireless...networks, we presume that the CR networks use CSMA/CA as the basis of their MAC protocol . It is also assumed that CR nodes can detect others

  18. Treatment considerations in carpal tunnel syndrome with coexistent Dupuytren's disease.

    Science.gov (United States)

    Nissenbaum, M; Kleinert, H E

    1980-11-01

    Twenty-nine patients with involvement of 31 hands presented with coexisting carpal tunnel syndrome and ipsilateral Dupuytren's disease. Analysis of the patient population showed a high proportion of women, dominant hand involvement, and repetitive manual trauma. Various treatment combinations were used and the results evaluated. Simultaneous surgical excision of Dupuytren's contracture and carpal tunnel release gave compromised long-term results, particularly among the women. To minimize complications, it is advised that carpal tunnel release not be performed at the same time as excision of Dupuytren's contracture.

  19. Molar Pregnancy with a Co-Existing Viable Fetus

    Directory of Open Access Journals (Sweden)

    Ruya Deveer

    2014-03-01

    Full Text Available     The aim of this study was to report the clinical features, management, and outcome of a case of molar pregnancy with a coexisting viable fetus and to review the literature. In this article, we report a case of pregnancy with diffuse placental molar change and a normal fetus which presented with hyperemesis gravidarum and hyperthyroidism. Genetic amniocentesis showed normal fetal karyotype. A healthy full-term live male infant was delivered by cesarean section. In molar pregnancies with a normal karyotype fetus, with intensive maternal follow-up, continuation of pregnancy can be suggested.

  20. Effect of hyperons on phase coexistence in strange matter

    CERN Document Server

    Das, P; Chaudhuri, G

    2016-01-01

    The study of liquid gas phase transition in fragmentation of nuclei in heavy ion collisions has been extended to the strangeness sector using the statistical model for multifragmentation. Helmholtz's free energy, specific heat and few other thermodynamic observables have been analyzed in order to examine the occurence of phase transition in the strange matter. The bimodal behaviour of the largest cluster formed in fragmentation also strongly indicates coexistence of both the phases. The presence of hyperons strengthens the signals and also shifts the transition temperature to lower values.

  1. Metazoan promoters

    DEFF Research Database (Denmark)

    Lenhard, Boris; Sandelin, Albin Gustav; Carninci, Piero

    2012-01-01

    Promoters are crucial for gene regulation. They vary greatly in terms of associated regulatory elements, sequence motifs, the choice of transcription start sites and other features. Several technologies that harness next-generation sequencing have enabled recent advances in identifying promoters...... and their features, helping researchers who are investigating functional categories of promoters and their modes of regulation. Additional features of promoters that are being characterized include types of histone modifications, nucleosome positioning, RNA polymerase pausing and novel small RNAs. In this Review, we...... discuss recent findings relating to metazoan promoters and how these findings are leading to a revised picture of what a gene promoter is and how it works....

  2. The citizen security reconfiguration: The security and coexistence policy for football in Colombia

    Directory of Open Access Journals (Sweden)

    Diego Felipe Puentes Sánchez

    2015-06-01

    Full Text Available Security policies are passing through a crucial time in which management strategies focused on crime, use of force and increasing clampdown on criminal matters, are inefficient in a scenario that promotes a normative spectrum linked to Human Rights seeking to insert the security as a condition for the construction of universal dignity in what the United Nations has called Human Security. This article is inserted in the current citizen security policy debates, to evidence how concepts such as Civic Culture and Culture of Peace are an inexorable prerequisite for the transformation to a Human Security approach, issue that goes through the possibility of promoting such change from perspectives that understand the conflicts in a broader and interdisciplinary manner. In order to this, the policy for security and coexistence for football in Colombia will be analyzed so as to have a practical and concrete example that will allow to evidence the expressed theoretical approaches and also because football has great social importance (economic, political and cultural in Colombia.

  3. Abundance analysis of DAZ white dwarfs

    CERN Document Server

    Kawka, Adela; Dinnbier, Frantisek; Cibulkova, Helena; Nemeth, Peter

    2010-01-01

    We present an abundance analysis of a sample of 33 hydrogen-rich (DA) white dwarfs. We have used archival high-resolution spectra to measure abundances of calcium, magnesium and iron in a set of 30 objects. In addition, we present preliminary calcium abundances in three new white dwarfs based on low-dispersion spectra. We investigate some abundance ratios (Mg/Ca, Fe/Ca) that may help uncover the composition of the accretion source.

  4. Distribution and coexistence of shrews in patchy landscapes: A field test of multiple hypotheses

    Science.gov (United States)

    Mortelliti, Alessio; Boitani, Luigi

    2009-11-01

    Despite the important role of shrews (Soricomorpha: Soricidae) in the functioning of ecosystems, as predators and prey, the effects of habitat loss and fragmentation on this guild of mammals are still unclear. We studied the distribution of 5 species (the greater white toothed shrew Crocidura leucodon; the lesser white toothed shrew Crocidura suaveolens; the pigmy shrew Sorex minutus; the Appennine shrew Sorex samniticus and the Etruscan shrew Suncus etruscus) in a fragmented landscape in central Italy. Shrews were trapped with pitfall traps made from plastic water bottles, the number of traps increased with patch size. A total of 170 individuals, of 5 species of shrews were captured. Shrews were widely distributed in our study area, however patch occupancy was determined mainly by vegetation and geometrical characteristics of the patches. Our data supports the hypotheses that patterns of habitat selection and the dynamics of seasonal abundance (habitat and temporal partitioning between similarly sized species) reduce competitive pressure, thus allowing coexistence of shrews in relatively species-rich assemblages, for such small amounts of habitat. The most important outcome of our results is the crucial role played by vegetation structure in determining distribution patterns. These results strongly suggest that measurements of the vegetation structure of habitat patches should always be included as explanatory variables when studying the distribution of shrews in fragmented landscapes.

  5. A lotka-volterra model of coexistence between a sexual population and multiple asexual clones.

    Science.gov (United States)

    Pound, Graeme E; Doncaster, C Patrick; Cox, Simon J

    2002-08-21

    At carrying capacity, small advantages in competitive ability can compensate a sexual population for its two-fold disadvantage in growth capacity when facing invasion by asexual mutants. In this paper, we develop a generic analytical model to consider the ecology of a sexual population comprising equal numbers of males and females, competing for shared prey resources with multiple female-only clones. We assume that the clones arise from the sexual population and are distinguished from it only by having narrower resource niches and twice the growth capacity. For sexual populations, at density-dependent carrying capacity, intra-specific competition between clonal individuals prevents them from realizing their two-fold advantage in intrinsic growth. This prediction leads to three novel outcomes: (i) a sexual population can coexist with any number of clones, provided their combined competitive impact remains less than the impact of the clones on each other; (ii) a sexual species can immediately exclude asexual invaders if it is a fast growing and strong competitor of shared resources and also has refuge in an abundant alternative resource; (iii) the rate of accumulation of clones in a sexual population will be slowed by intra and inter-specific competition amongst the clones themselves, in addition to the competitive impact from the original sexual population.

  6. Planetary nebulae abundances and stellar evolution

    NARCIS (Netherlands)

    Pottasch, S. R.; Bernard-Salas, J.

    2006-01-01

    A summary is given of planetary nebulae abundances from ISO measurements. It is shown that these nebulae show abundance gradients (with galactocentric distance), which in the case of neon, argon, sulfur and oxygen (with four exceptions) are the same as HII regions and early type star abundance gradi

  7. Planetary nebulae abundances and stellar evolution II

    NARCIS (Netherlands)

    Pottasch, S. R.; Bernard-Salas, J.

    2010-01-01

    Context. In recent years mid-and far infrared spectra of planetary nebulae have been analysed and lead to more accurate abundances. It may be expected that these better abundances lead to a better understanding of the evolution of these objects. Aims. The observed abundances in planetary nebulae are

  8. Shape coexistence in the microscopically guided interacting boson model

    CERN Document Server

    Nomura, K; Van Isacker, P

    2015-01-01

    Shape coexistence has been a subject of great interest in nuclear physics for many decades. In the context of the nuclear shell model, intruder excitations may give rise to remarkably low-lying excited $0^+$ states associated with different intrinsic shapes. In heavy open-shell nuclei, the dimension of the shell-model configuration space that includes such intruder excitations becomes exceedingly large, thus requiring a drastic truncation scheme. Such a framework has been provided by the interacting boson model (IBM). In this article we address the phenomenon of shape coexistence and its relevant spectroscopy from the point of view of the IBM. A special focus is placed on the method developed recently which makes use of the link between the IBM and the self-consistent mean-field approach based on the nuclear energy density functional. The method is extended to deal with various intruder configurations associated with different equilibrium shapes. We assess the predictive power of the method and suggest possib...

  9. Explosive synchronization coexists with classical synchronization in the Kuramoto model

    Science.gov (United States)

    Danziger, Michael M.; Moskalenko, Olga I.; Kurkin, Semen A.; Zhang, Xiyun; Havlin, Shlomo; Boccaletti, Stefano

    2016-06-01

    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 ˜ 106) 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.

  10. On the dispersion of two coexisting nongyrotropic ion species

    Directory of Open Access Journals (Sweden)

    A. L. Brinca

    Full Text Available Space observations in the solar wind and simulations of high Mach number bow-shocks have detected particle populations with two coexisting nongyrotropic ion species. We investigate the influence of these two sources of free energy on the stability of parallel (with respect to the ambient magnetic field and perpendicular propagation. For parallel modes, we derive their dispersion equation in a magnetoplasma with protons and alpha particles that may exhibit stationary nongyrotropy (SNG and discuss the characteristics of its solutions. Kinetic simulations study the behaviour of perpendicular electrostatic (Bernstein-like waves in a plasma whose ion populations (positrons and fictitious singly-charged particles with twice the electron mass, for the sake of simulation feasability can be time-varying nongyrotropic (TNG. The results show that the coexistence of two gyrophase bunched species does not significantly enhance the parallel SNG instability already found for media with only one nongyrotropic species, whereas it strongly intensifies the growth of Bernstein-like modes in TNG plasmas.

    Key words. Magnetospheric physics (plasma waves and instabilities · Space plasma physics (numerical simulation studies; waves and instabilities

  11. 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.

  12. Phase Coexistence in Nanoscopically Thin Films Confined by Asymmetric Walls

    Science.gov (United States)

    Albano, Ezequiel V.; Binder, Kurt

    2009-06-01

    Thin Ising films with nearest-neighbor ferromagnetic exchange in a bulk magnetic field H are studied in a L× L× D geometry, where at the opposite walls, given by the L× L surfaces, local magnetic fields H 1, and H D act. While in previous work, the symmetric case H 1= H D (leading to "capillary condensation", when one applies the lattice gas terminology) as well as the antisymmetric case H 1=- H D (leading to "interface localization transitions") were studied, we focus here on the general `asymmetric' case. Monte Carlo simulations are carried out and analyses based on thermodynamic integration methods are used to establish the phase diagrams and study the properties of the coexisting phases. A discussion is given why for the range of thicknesses that is explored (16≤ D≤80 lattice spacings) this is the most suitable methodology. Restricting attention to cases where in the semi-infinite system a first-order wetting transition occurs, it is shown that the latter, due to confinement, is turned in a thin-film triple point. Above the triple point, narrow two-phase coexistence curves are found, which are the analog of prewetting transitions in the semi-infinite system. A comparison to related results for (symmetrical) polymer blends and (asymmetric) colloid-polymer mixtures is made.

  13. Phase coexistence in manganites: doping and structural dependence

    Energy Technology Data Exchange (ETDEWEB)

    Alejandro, G; Granada, M; Laura-Ccahuana, D; Tovar, M; Winkler, E; Causa, M T [Centro Atomico Bariloche, 8400 San Carlos de Bariloche, RIo Negro (Argentina); Otero-Leal, M, E-mail: galejand@cab.cnea.gov.a [Departamentos de Quimica-Fisica y Fisica Aplicada, Universidad de Santiago de Compostela, 15782-Santiago de Compostela (Spain)

    2010-06-30

    We present a study on the phase coexistence (PC) of paramagnetic insulating (PM-I) and ferromagnetic metallic (FM-M) phases in the La{sub 1-y}(Ca{sub 1-x}Sr{sub x}){sub y}MnO{sub 3} system with 0.23 {<=} y {<=} 0.45. The study was performed by means of magnetization and electron spin resonance (ESR) measurements. At high temperatures the ESR spectrum consists of a single symmetric PM line. At T{sub C}, a FM asymmetric line is observed shifted to low fields. In a {Delta}T temperature range both lines are visible, defining a range of PC. For x = 0, we obtained {Delta}T as a function of the carrier concentration y, finding that the largest {Delta}T corresponds to y = 0.25. For this y value, the extreme compounds are orthorhombic and rhombohedral for x = 0 and 1, respectively. The rhombohedral to orthorhombic temperature transition (T{sub RO}) was determined as a function of x. We found that {Delta}T{ne}0 only if T{sub C} < T{sub RO}. The PM-I/FM-M phase coexistence was only observed in the orthorhombic phase while seems to be incompatible with the more symmetric rhombohedral phase.

  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. Coexistence of osteopoikilosis with seronegative spondyloarthritis and spinal stenosis

    Science.gov (United States)

    Demir, Saliha Eroglu; Özaras, Nihal; Poyraz, Emine; Toprak, Hüseyin; Güler, Mustafa

    2015-01-01

    [Purpose] Osteopoikilosis is a rare hereditary bone disease that is usually asymptomatic. It is generally diagnosed incidentally on plain radiography. The coexistence of osteopoikilosis with seronegative spondyloarthritis or spinal stenosis is rarely reported. Here, we report the case of a 27-year-old male patient with osteopoikilosis, seronegative spondyloarthritis, and spinal stenosis. [Subject] A 27-year-old male patient with buttock pain and back pain radiating to the legs. [Methods] A plain anteroposterior radiograph of the pelvis revealed numerous round and oval sclerotic bone areas of varying size. Investigation of the knee joints showed similar findings, and the patient was diagnosed with osteopoikilosis. Lumbar magnetic resonance images showed spinal stenosis and degenerative changes in his lumbar facet joints. Magnetic resonance images of the sacroiliac joints showed bilateral involvement with narrowing of both sacroiliac joints, nodular multiple sclerotic foci, and contrast enhancement in both joint spaces and periarticular areas. HLA B-27 test was negative. [Results] The patient was diagnosed with osteopoikilosis, seronegative spondyloarthritis, and spinal stenosis. Treatment included asemetasin twice daily and exercise therapy. [Conclusion] Symptomatic patients with osteopoikilosis should be investigated for other possible coexisting medical conditions; this will shorten the times to diagnosis and treatment. PMID:26157277

  16. Coexistence of ferromagnetism and superconductivity in YBCO nanoparticles.

    Science.gov (United States)

    Zhu, Zhonghua; Gao, Daqiang; Dong, Chunhui; Yang, Guijin; Zhang, Jing; Zhang, Jinlin; Shi, Zhenhua; Gao, Hua; Luo, Honggang; Xue, Desheng

    2012-03-21

    Nanoparticles of superconducting YBa(2)Cu(3)O(7-δ) were synthesized via a citrate pyrolysis technique. Room temperature ferromagnetism was revealed in the samples by a vibrating sample magnetometer. Electron spin resonance spectra at selected temperatures indicated that there is a transition from the normal to the superconducting state at temperatures below 100 K. The M-T curves with various applied magnetic fields showed that the superconducting transition temperatures are 92 K and 55 K for the air-annealed and the post-annealed samples, respectively. Compared to the air-annealed sample, the saturation magnetization of the sample by reheating the air-annealed one in argon atmosphere is enhanced but its superconductivity is weakened, which implies that the ferromagnetism maybe originates from the surface oxygen defects. By superconducting quantum interference device measurements, we further confirmed the ferromagnetic behavior at high temperatures and interesting upturns in field cooling magnetization curves within the superconducting region are found. We attributed the upturn phenomena to the coexistence of ferromagnetism and superconductivity at low temperatures. Room temperature ferromagnetism of superconducting YBa(2)Cu(3)O(7-δ) nanoparticles has been observed in some previous related studies, but the issue of the coexistence of ferromagnetism and superconductivity within the superconducting region is still unclear. In the present work, it will be addressed in detail. The cooperation phenomena found in the spin-singlet superconductors will help us to understand the nature of superconductivity and ferromagnetism in more depth.

  17. Clean relaying aided cognitive radio under the coexistence constraint

    CERN Document Server

    Lin, Pin-Hsun; Su, Hsuan-Jung; Hong, Y -W Peter

    2011-01-01

    We consider the interference-mitigation based cognitive radio where the primary and secondary users can coexist at the same time and frequency bands, under the constraint that the rate of the primary user (PU) must remain the same with a single-user decoder. To meet such a coexistence constraint, the relaying from the secondary user (SU) can help the PU's transmission under the interference from the SU. However, the relayed signal in the known dirty paper coding (DPC) based scheme is interfered by the SU's signal, and is not "clean". In this paper, under the half-duplex constraints, we propose two new transmission schemes aided by the clean relaying from the SU's transmitter and receiver without interference from the SU. We name them as the clean transmitter relaying (CT) and clean transmitter-receiver relaying (CTR) aided cognitive radio, respectively. The rate and multiplexing gain performances of CT and CTR in fading channels with various availabilities of the channel state information at the transmitters ...

  18. Coexistence of Interacting Opinions in a Generalized Sznajd Model

    CERN Document Server

    Timpanaro, André M

    2011-01-01

    The Sznajd model is a sociophysics model that mimics the propagation of opinions in a closed society, where the interactions favour groups of agreeing people. It is based in the Ising and Potts ferromagnetic models and although the original model used only linear chains, it has since been adapted to general networks. This model has a very rich transient, that has been used to model several aspects of elections, but its stationary states are always consensus states. In order to model more complex behaviours we have, in a recent work, introduced the idea of biases and prejudices to the Sznajd model, by generalizing the bounded confidence rule that is common to many continuous opinion models. In that work we have found that the mean-field version of this model (corresponding to a complete network) allows for stationary states where non-interacting opinions survive, but never for the coexistence of interacting opinions. In the present work, we provide networks that allow for the coexistence of interacting opinion...

  19. 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.

  20. The evolution of antiherbivore defenses and their contribution to species coexistence in the tropical tree genus Inga

    Science.gov (United States)

    Kursar, Thomas A.; Dexter, Kyle G.; Lokvam, John; Pennington, R. Toby; Richardson, James E.; Weber, Marjorie G.; Murakami, Eric T.; Drake, Camilla; McGregor, Ruth; Coley, Phyllis D.

    2009-01-01

    Plants and their herbivores constitute more than half of the organisms in tropical forests. Therefore, a better understanding of the evolution of plant defenses against their herbivores may be central for our understanding of tropical biodiversity. Here, we address the evolution of antiherbivore defenses and their possible contribution to coexistence in the Neotropical tree genus Inga (Fabaceae). Inga has >300 species, has radiated recently, and is frequently one of the most diverse and abundant genera at a given site. For 37 species from Panama and Peru we characterized developmental, ant, and chemical defenses against herbivores. We found extensive variation in defenses, but little evidence of phylogenetic signal. Furthermore, in a multivariate analysis, developmental, ant, and chemical defenses varied independently (were orthogonal) and appear to have evolved independently of each other. Our results are consistent with strong selection for divergent defensive traits, presumably mediated by herbivores. In an analysis of community assembly, we found that Inga species co-occurring as neighbors are more different in antiherbivore defenses than random, suggesting that possessing a rare defense phenotype increases fitness. These results imply that interactions with herbivores may be an important axis of niche differentiation that permits the coexistence of many species of Inga within a single site. Interactions between plants and their herbivores likely play a key role in the generation and maintenance of the conspicuously high plant diversity in the tropics. PMID:19805183

  1. Doubly twisted Neimark–Sacker bifurcation and two coexisting two-dimensional tori

    Energy Technology Data Exchange (ETDEWEB)

    Sekikawa, Munehisa, E-mail: sekikawa@cc.utsunomiya-u.ac.jp [Department of Mechanical and Intelligent Engineering, Utsunomiya University, Utsunomiya 321-8585 (Japan); Inaba, Naohiko [Organization for the Strategic Coordination of Research and Intellectual Properties, Meiji University, Kawasaki 214-8571 (Japan)

    2016-01-08

    We discuss a complicated bifurcation structure involving several quasiperiodic bifurcations generated in a three-coupled delayed logistic map where a doubly twisted Neimark–Sacker bifurcation causes a transition from two coexisting periodic attractors to two coexisting invariant closed circles (ICCs) corresponding to two two-dimensional tori in a vector field. Such bifurcation structures are observed in Arnol'd tongues. Lyapunov and bifurcation analyses suggest that the two coexisting ICCs and the two coexisting periodic solutions almost overlap in the two-parameter bifurcation diagram. - Highlights: • This study investigates a three-coupled delayed logistic map. • It generates complex quasiperiodic bifurcations. • Two periodic solution coexist in a conventional Arnol'd tongue. • Two two-tori coexist in a high-dimensional Arnol'd tongue.

  2. 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 ...

  3. Origin of Cosmic Chemical Abundances

    CERN Document Server

    Maio, Umberto

    2015-01-01

    Cosmological N-body hydrodynamic computations following atomic and molecular chemistry (e$^-$, H, H$^+$, H$^-$, He, He$^+$, He$^{++}$, D, D$^+$, H$_2$, H$_2^+$, HD, HeH$^+$), gas cooling, star formation and production of heavy elements (C, N, O, Ne, Mg, Si, S, Ca, Fe, etc.) from stars covering a range of mass and metallicity are used to explore the origin of several chemical abundance patterns and to study both the metal and molecular content during simulated galaxy assembly. The resulting trends show a remarkable similarity to up-to-date observations of the most metal-poor damped Lyman-$\\alpha$ absorbers at redshift $z\\gtrsim 2$. These exhibit a transient nature and represent collapsing gaseous structures captured while cooling is becoming effective in lowering the temperature below $\\sim 10^4\\,\\rm K$, before they are disrupted by episodes of star formation or tidal effects. Our theoretical results agree with the available data for typical elemental ratios, such as [C/O], [Si/Fe], [O/Fe], [Si/O], [Fe/H], [O/...

  4. [A patient with coexistence of primary hyperparathyroidism, Marfan's syndrome and von Willebrand's disease].

    Science.gov (United States)

    Bednarek-Tupikowska, Grazyna; Rakowska-Chort, Anna; Adamarczuk-Janczyszyn, Maria

    2008-01-01

    We presented a case of a 58 year old women suffering from three diseases: primary hyperparathyroidism, Marfan's syndrome and von Willebrand's disease. The coexistence of these diseases is not mentioned in medical literature. Because of the coexistence of Marfan's syndrome with primary hyperparathyroidism, the examinations of other endocrinopathy including multiple endocrine neoplasia (MEN). Their coexistence was not confirmed at the present time. In this paper the new views on both patogenesis and treatment of the mentioned diseases were included.

  5. Best practice document for coexistence of genetically modified soybean crops with conventional and organic farming

    OpenAIRE

    2014-01-01

    The present technical report deals with coexistence issues of genetically modified (GM) soybean cultivation with non-GM soybean and honey production in the EU. The Technical Working Group (TWG) for Soybean of the European Coexistence Bureau (ECoB) analysed the possible sources for potential GM cross-pollination and admixture and agreed on the best practices for coexistence. The terms of reference for this review are presented in Section 1. The scope of the Best Practice Document is coexistenc...

  6. Coexisting Oscillation and Extreme Multistability for a Memcapacitor-Based Circuit

    OpenAIRE

    Guangyi Wang; Chuanbao Shi; Xiaowei Wang; Fang Yuan

    2017-01-01

    The coexisting oscillations are observed with a memcapacitor-based circuit that consists of two linear inductors, two linear resistors, and an active nonlinear charge-controlled memcapacitor. We analyze the dynamics of this circuit and find that it owns an infinite number of equilibrium points and coexisting attractors, which means extreme multistability arises. Furthermore, we also show the stability of the infinite many equilibria and analyze the coexistence of fix point, limit cycle, and c...

  7. Obinutuzumab plus chlorambucil in patients with CLL and coexisting conditions.

    Science.gov (United States)

    Goede, Valentin; Fischer, Kirsten; Busch, Raymonde; Engelke, Anja; Eichhorst, Barbara; Wendtner, Clemens M; Chagorova, Tatiana; de la Serna, Javier; Dilhuydy, Marie-Sarah; Illmer, Thomas; Opat, Stephen; Owen, Carolyn J; Samoylova, Olga; Kreuzer, Karl-Anton; Stilgenbauer, Stephan; Döhner, Hartmut; Langerak, Anton W; Ritgen, Matthias; Kneba, Michael; Asikanius, Elina; Humphrey, Kathryn; Wenger, Michael; Hallek, Michael

    2014-03-20

    The monoclonal anti-CD20 antibody rituximab, combined with chemotherapeutic agents, has been shown to prolong overall survival in physically fit patients with previously untreated chronic lymphocytic leukemia (CLL) but not in those with coexisting conditions. We investigated the benefit of the type 2, glycoengineered antibody obinutuzumab (also known as GA101) as compared with that of rituximab, each combined with chlorambucil, in patients with previously untreated CLL and coexisting conditions. We randomly assigned 781 patients with previously untreated CLL and a score higher than 6 on the Cumulative Illness Rating Scale (CIRS) (range, 0 to 56, with higher scores indicating worse health status) or an estimated creatinine clearance of 30 to 69 ml per minute to receive chlorambucil, obinutuzumab plus chlorambucil, or rituximab plus chlorambucil. The primary end point was investigator-assessed progression-free survival. The patients had a median age of 73 years, creatinine clearance of 62 ml per minute, and CIRS score of 8 at baseline. Treatment with obinutuzumab-chlorambucil or rituximab-chlorambucil, as compared with chlorambucil monotherapy, increased response rates and prolonged progression-free survival (median progression-free survival, 26.7 months with obinutuzumab-chlorambucil vs. 11.1 months with chlorambucil alone; hazard ratio for progression or death, 0.18; 95% confidence interval [CI], 0.13 to 0.24; Pchlorambucil vs. 11.1 months with chlorambucil alone; hazard ratio, 0.44; 95% CI, 0.34 to 0.57; Pchlorambucil, as compared with chlorambucil alone, prolonged overall survival (hazard ratio for death, 0.41; 95% CI, 0.23 to 0.74; P=0.002). Treatment with obinutuzumab-chlorambucil, as compared with rituximab-chlorambucil, resulted in prolongation of progression-free survival (hazard ratio, 0.39; 95% CI, 0.31 to 0.49; Pchlorambucil than with rituximab-chlorambucil, but the risk of infection was not increased. Combining an anti-CD20 antibody with chemotherapy

  8. 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

  9. Floral abundance, richness, and spatial distribution drive urban garden bee communities.

    Science.gov (United States)

    Plascencia, M; Philpott, S M

    2017-03-01

    In urban landscapes, gardens provide refuges for bee diversity, but conservation potential may depend on local and landscape features. Foraging and population persistence of bee species, as well as overall pollinator community structure, may be supported by the abundance, richness, and spatial distribution of floral resources. Floral resources strongly differ in urban gardens. Using hand netting and pan traps to survey bees, we examined whether abundance, richness, and spatial distribution of floral resources, as well as ground cover and garden landscape surroundings influence bee abundance, species richness, and diversity on the central coast of California. Differences in floral abundance and spatial distribution, as well as urban cover in the landscape, predicted different bee community variables. Abundance of all bees and of honeybees (Apis mellifera) was lower in sites with more urban land cover surrounding the gardens. Honeybee abundance was higher in sites with patchy floral resources, whereas bee species richness and bee diversity was higher in sites with more clustered floral resources. Surprisingly, bee species richness and bee diversity was lower in sites with very high floral abundance, possibly due to interactions with honeybees. Other studies have documented the importance of floral abundance and landscape surroundings for bees in urban gardens, but this study is the first to document that the spatial arrangement of flowers strongly predicts bee abundance and richness. Based on these findings, it is likely that garden managers may promote bee conservation by managing for floral connectivity and abundance within these ubiquitous urban habitats.

  10. SteadyCom: Predicting microbial abundances while ensuring community stability.

    Directory of Open Access Journals (Sweden)

    Siu Hung Joshua Chan

    2017-05-01

    Full Text Available Genome-scale metabolic modeling has become widespread for analyzing microbial metabolism. Extending this established paradigm to more complex microbial communities is emerging as a promising way to unravel the interactions and biochemical repertoire of these omnipresent systems. While several modeling techniques have been developed for microbial communities, little emphasis has been placed on the need to impose a time-averaged constant growth rate across all members for a community to ensure co-existence and stability. In the absence of this constraint, the faster growing organism will ultimately displace all other microbes in the community. This is particularly important for predicting steady-state microbiota composition as it imposes significant restrictions on the allowable community membership, composition and phenotypes. In this study, we introduce the SteadyCom optimization framework for predicting metabolic flux distributions consistent with the steady-state requirement. SteadyCom can be rapidly converged by iteratively solving linear programming (LP problem and the number of iterations is independent of the number of organisms. A significant advantage of SteadyCom is compatibility with flux variability analysis. SteadyCom is first demonstrated for a community of four E. coli double auxotrophic mutants and is then applied to a gut microbiota model consisting of nine species, with representatives from the phyla Bacteroidetes, Firmicutes, Actinobacteria and Proteobacteria. In contrast to the direct use of FBA, SteadyCom is able to predict the change in species abundance in response to changes in diets with minimal additional imposed constraints on the model. By randomizing the uptake rates of microbes, an abundance profile with a good agreement to experimental gut microbiota is inferred. SteadyCom provides an important step towards the cross-cutting task of predicting the composition of a microbial community in a given environment.

  11. Hydrocarbon Reserves: Abundance or Scarcity

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    IFP and the OAPEC jointly organize a regular international seminar dealing with world oil-related problems appearing in the news. For the first time, this seminar has been opened to oil and gas company specialists, service companies, research centers and independents. This year's theme concerns oil and gas reserves: are they abundant or are we headed towards the shortages announced by some experts? This theme is especially topical in that: oil and gas currently meet two thirds of world energy needs and almost completely dominate the transport sector; the reserves declared by the OAPEC countries account for nearly half of world reserves; the price of a barrel of oil went through the roof in 2004; world energy demand is growing fast and alternative sources of energy are far from ready to take over from oil and gas in the next few decades. Since the reserves correspond to the volume it is technically and economically viable to produce, the seminar has, of course, dealt with the technical and economic questions that arise in connection with exploration and production, but it has also considered changes in the geopolitical context. Presentations by the leading companies of the OAPEC countries and by the IFP group were completed by presentation from the International Energy Agency (IEA), the United States Geological Survey (USGS), the IHS Energy Group, Total and Gaz de France. This document gathers the transparencies of the following presentations: Hydrocarbon reserves in OAPEC members countries: current and future (M. Al-Lababidi); Non OAPEC liquid reserves and production forecasts (Y. Mathieu); World oil and gas resources and production outlook (K. Chew); Global investments in the upstream (F. Birol); Total's policy in the oil and gas sector (C. de Margerie); Gaz de France's policy in the oil and gas sector (J. Abiteboul); NOC/IOC's opportunities in OPEC countries (I. Sandrea); Relationships between companies, countries and investors: How they may

  12. New interpretation of shape coexistence in {sup 99}Zr

    Energy Technology Data Exchange (ETDEWEB)

    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. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FIN-40351, Jyvaeskylae (Finland)

    1997-11-01

    Levels in {sup 99}Zr populated by {beta} decay of on-line mass separated {sup 99}Y have been studied by {gamma}-ray spectroscopic methods, including {gamma}-{gamma} 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 {sup 99}Zr. Transition rates and {gamma}-ray branching ratios make a new level at 679 keV with t{sub 1/2}=9 ns another candidate for a deformed state. {copyright} {ital 1997} {ital The American Physical Society}

  13. Coexistence of negative photoconductivity and hysteresis in semiconducting graphene

    Science.gov (United States)

    Zhuang, Shendong; Chen, Yan; Xia, Yidong; Tang, Nujiang; Xu, Xiaoyong; Hu, Jingguo; Chen, Zhuo

    2016-04-01

    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.

  14. Coexistence of negative photoconductivity and hysteresis in semiconducting graphene

    Directory of Open Access Journals (Sweden)

    Shendong Zhuang

    2016-04-01

    Full Text Available 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.

  15. Coexisting coherent and incoherent domains near saddle-node bifurcation

    Science.gov (United States)

    Chandrasekar, V. K.; Suresh, R.; Senthilkumar, D. V.; Lakshmanan, M.

    2015-09-01

    A common external forcing can cause a saddle-node bifurcation in an ensemble of identical Duffing oscillators by breaking the symmetry of the individual bistable (double-well) unit. The strength of the forcing determines the separation between the saddle and the node, which in turn dictates different dynamical transitions depending on the distribution of the initial states of the oscillators. In particular, chimera-like states appear in the vicinity of the saddle-node bifurcation for which theoretical explanation is provided from the stability of the steady state of the slow-scale dynamics of the original system of equations. Further, we have also established similar states by replacing the external forcing with an appropriate coupling between the oscillators in the same parameter space. Additionally, we have also designed an appropriate coupling that can lead to saddle-node bifurcation due to symmetry breaking of the bistable systems in the vicinity of which the synchronized and desynchronized domains coexist.

  16. Coexistence of Major Complications in Pancreatic Pseudocyst: Case report

    Directory of Open Access Journals (Sweden)

    Ömer Fatih Nas

    2016-06-01

    Full Text Available Pancreatic pseudocyst is the most common cystic lesion of the pancreas seen following acute and chronic pancreatitis in 2-10% and 10-30%, respectively. Imaging findings vary depending on the age and severity of the attack. Infection, hemorrhage and rupture are the most frightening complications. The possibility of spontaneous recovery is consider­ably low. A 63-year old male patient who has history of longstanding alcohol consumption presented to the emer­gency department with complaints of abdominal pain. On computerized tomography (CT, an encapsulated and round peripancreatic collection with a size of approximately 8.5x7.5 cm was detected in pancreatic head. In the literature, no article is published mentioning coexistence of complication such as infection, hemorrhage and rupture. We present the association of these three complications observed in our case. J Clin Exp Invest 2016; 7 (2: 203-206

  17. 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.

  18. Two phase coexistence for the hydrogen-helium mixture

    CERN Document Server

    Fantoni, Riccardo

    2015-01-01

    We use our newly constructed quantum Gibbs ensemble Monte Carlo algorithm to perform computer experiments for the two phase coexistence of a hydrogen-helium mixture. Our results are in quantitative agreement with the experimental results of C. M. Sneed, W. B. Streett, R. E. Sonntag, and G. J. Van Wylen. The difference between our results and the experimental ones is in all cases less than 15% relative to the experiment, reducing to less than 5% in the low helium concentration phase. At the gravitational inversion between the vapor and the liquid phase, at low temperatures and high pressures, the quantum effects become relevant. At extremely low temperature and pressure the first component to show superfluidity is the helium in the vapor phase.

  19. Coexistence between Cyphomyrmex ants and dominant populations of Wasmannia auropunctata.

    Science.gov (United States)

    Grangier, Julien; Le Breton, Julien; Dejean, Alain; Orivel, Jérôme

    2007-01-10

    The little fire ant Wasmannia auropunctata is able to develop highly dominant populations in disturbed areas of its native range, with a resulting negative impact on ant diversity. We report here on the tolerance of such populations towards several fungus-growing ants of the genus Cyphomyrmex (rimosus complex) in French Guiana. This tolerance is surprising given the usually high interspecific aggressiveness of W. auropunctata when dominant. In order to understand the mechanisms behind such proximity, aggressiveness tests were performed between workers of the different species. These behavioural assays revealed a great passivity in Cyphomyrmex workers during confrontations with W. auropunctata workers. We also found that the aggressiveness between W. auropunctata and two Cyphomyrmex species was more intense between distant nests than between adjacent ones. This dear-enemy phenomenon may result from a process of habituation contributing to the ants' ability to coexist over the long term.

  20. Coexistence of exponentially many chaotic spin-glass attractors.

    Science.gov (United States)

    Peleg, Y; Zigzag, M; Kinzel, W; Kanter, I

    2011-12-01

    A chaotic network of size N with delayed interactions which resembles a pseudoinverse associative memory neural network is investigated. For a load α = P/N chaotic network functions as an associative memory of 2P attractors with macroscopic basin of attractions which decrease with α. At finite α, a chaotic spin-glass phase exists, where the number of distinct chaotic attractors scales exponentially with N. Each attractor is characterized by a coexistence of chaotic behavior and freezing of each one of the N chaotic units or freezing with respect to the P patterns. Results are supported by large scale simulations of networks composed of Bernoulli map units and Mackey-Glass time delay differential equations.

  1. 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.

  2. Coexistence of xanthogranulomatous cholecystitis and gallbladder adenocarcinoma: a fortuitous association?

    Science.gov (United States)

    Limaiem, F; Chelly, B; Hassan, F; Haddad, I; Ben Slama, S; Lahmar, A; Bouraoui, S; Mzabi-Regaya, S

    2013-08-01

    Xanthogranulomatous cholecystitis is a relatively uncommon variant of chronic cholecystitis, characterized by marked thickening of the gallbladder wall and dense local adhesions. Not only does xanthogranulomatous cholecystitis mimic malignancy, it can also be infrequently associated with gallbladder carcinoma in 0.2% to 35.4% of cases. Herein, the authors report a new case of xanthogranulomatous cholecystitis concomitant with gallbladder adenocarcinoma in a 65-year-old female patient. Because of its overlapping clinical, radiological and macroscopic findings with gallbladder cancer, definitive diagnosis of xanthogranulomatous cholecystitis relies on extensive sampling and thorough microscopic examination of the surgical specimen to exclude the possibility of coexisting tumour. It is still a matter of debate whether xanthogranulomatous cholecystitis is truly a precursor of gallbladder carcinoma or if it is just an incidental finding. This aspect needs to be explored in the future with further studies.

  3. Towards a coexistence of paradigms in nursing knowledge development.

    Science.gov (United States)

    Cull-Wilby, B L; Pepin, J I

    1987-07-01

    During the last 35 years, nursing knowledge has known a surge in its development. Following the evolution of the scientific world, nursing first embraced the logical empiricist perspective of discovering and knowing. Historicism and, more recently, critical social theory have been explored as alternative ways of making knowledge in nursing. This paper discusses the evolution of nursing knowledge, considering its past and present activities. The authors suggest that a cooperative attitude amongst nurses, and a coexistence of various paradigms of knowledge development characterize the future of nursing. Nursing knowledge should be understood as a stage in its evolution and growth. The result of this process will never be a final static body of knowledge. Knowledge expansion will be encouraged through a process of integrating components from different research traditions, such that a multidimensional understanding of phenomena will be realised.

  4. 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.

  5. [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

  6. Coexistence of Colon Cancer and Diverticilutis Complicated with Diverticular Abscess

    Directory of Open Access Journals (Sweden)

    Dursun Ozgur Karakas

    2015-12-01

    Full Text Available Coexistence of a diverticular abscess and colorectal cancer is an extremely rare phenomenon. The clinical presentation and the extension of a diverticular abscess could cause mis-staging of colon cancer. We are presenting an overstaged colon cancer due to a diverticular abscess penetrating into the abdominal wall. A 65-year-old male patient with a history of an enlarging mass in the left lower quadrant of the abdomen was admitted to our service. Diagnostic studies revealed a sigmoid tumor communicating with an abdominal wall mass. The patient was clinically staged as T4 N1. Exploration revealed a diverticular abscess penetrating into the abdominal wall and a sigmoid tumor. Histopathological examination reported an intermediately differentiated T3 N0 adenocarcinoma of the sigmoid colon. After an uneventful postoperative recovery, the patient was referred to chemotherapy. [Arch Clin Exp Surg 2015; 4(4.000: 231-233

  7. Coexisting normal and triaxial superdeformed structures in {sup 165}Lu

    Energy Technology Data Exchange (ETDEWEB)

    Schoenwasser, G.; Nenoff, N.; Huebel, H. E-mail: hubel@iskp.uni-bonn.de; Hagemann, G.B.; Bednarczyk, P.; Benzoni, G.; Bracco, A.; Bringel, P.; Chapman, R.; Curien, D.; Domscheit, J.; Herskind, B.; Jensen, D.R.; Leoni, S.; Lo Bianco, G.; Ma, W.C.; Maj, A.; Neusser, A.; Oedegaard, S.W.; Petrache, C.M.; Rossbach, D.; Ryde, H.; Singh, A.K.; Spohr, K.H

    2004-05-03

    High-spin states in {sup 165}Lu were populated in the {sup 139}La({sup 30}Si,4n) reaction at a beam energy of 152 MeV and {gamma}-ray coincidences were measured with the EUROBALL spectrometer array. Nine new rotational bands were discovered, known band structures were considerably extended and many inter-band transitions were found. Structures with normal deformation coexist with bands associated with the strongly deformed triaxial energy minima found in calculations. Three of these triaxial bands form a family of wobbling excitations with phonon quanta n{sub w}=0, 1 and 2. The wobbling mode is a unique signature of nuclear triaxiality. Configuration assignments are discussed for the observed band structures. An exchange of configuration between two of the new bands due to mixing is observed, resulting in different signature partnerships at low and high spins.

  8. Shape Co-Existence in the Transitional Nuclide 157Yb

    Institute of Scientific and Technical Information of China (English)

    徐川; 华辉; 李湘庆; 张双全; 许甫荣; 石跃; 竺礼华; 吴晓光; 李广生; 贺创业

    2012-01-01

    High-spin states in 157Yb have been populated in the 144Sm(160, 3n)157yb fusion- evaporation reaction at a beam energy of 85 MeV, and two rotational bands have been established for the first time. Within the framework of the triaxial particle-rotor model, the energy spectra and single-particle configurations of 157Yb are investigated. The calculated energy spectra agree well with the experimental data. The newly observed vf7/2 band, and the previously known vi13/2 band in 157Yb, are also discussed by means of Total-Routhian-Surface methods. The structural characters observed in 157Yb provide evidence for the shape coexistence of three distinct shapes: prolate, triaxial and oblate. At higher spins, both the vf7/2 band and the vi13/2 band in 157Yb undergo a shape evolution with sizable alignments occurring.

  9. Co-existence of Pulmonary, Tonsillar and Laryngeal Tuberculosis

    Directory of Open Access Journals (Sweden)

    Erkan Ceylan

    2013-10-01

    Full Text Available    A 56-year old man applied to otorhinolaryngology clinic with sore throat, dysphagia. During direct examination, left palatine tonsil and tonsil plicas ulcerovegetative lesions were found. In the indirect laryngoscopy, in some regions of the larynx and epiglottis, ulcerovegetative lesions were observed too. Because of suspicion of laryngeal carcinoma and metastasis, punch biopsy of the left palatine tonsil was performed. Chest x-ray and computerized tomography of the thorax revealed two adjacent cavitations in the apicoposterior segment of the left upper lobe. In the histopathologic examination of biopsies, granulomatous structures that proved tuberculosis were observed. In the fiberoptic bronchoscopic analysis, endobronchial lesion was not detected. Acid-fast bacilli were determined in sputum and bronchial lavage in microscopy and culture. The case of this middle aged male patient with co-existence of tonsillar, laryngeal and pulmonary tuberculosis presents the clinical significance of upper airway tuberculosis in terms of its infectiousness and rare occurrence.

  10. ANALYSIS OF WIFI AND WIMAX AND WIRELESS NETWORK COEXISTENCE

    Directory of Open Access Journals (Sweden)

    Shuang Song

    2014-12-01

    Full Text Available Wireless networks are very popular nowadays. Wireless Local Area Network (WLAN that uses the IEEE 802.11 standard and WiMAX (Worldwide Interoperability for Microwave Access that uses the IEEE 802.16 standard are networks that we want to explore. WiMAX has been developed over 10 years, but it is still unknown by most people. However, compared with WLAN, it has many advantages in transmission speed and coverage area. This paper will introduce these two technologies and make comparisons between WiMAX and WiFi. In addition, wireless network coexistence of WLAN and WiMAX will be explored through simulation. Lastly we want to discuss the future of WiMAX in relation to WiFi.

  11. Fair and unfair punishers coexist in the Ultimatum Game

    Science.gov (United States)

    Brañas-Garza, Pablo; Espín, Antonio M.; Exadaktylos, Filippos; Herrmann, Benedikt

    2014-01-01

    In the Ultimatum Game, a proposer suggests how to split a sum of money with a responder. If the responder rejects the proposal, both players get nothing. Rejection of unfair offers is regarded as a form of punishment implemented by fair-minded individuals, who are willing to impose the cooperation norm at a personal cost. However, recent research using other experimental frameworks has observed non-negligible levels of antisocial punishment by competitive, spiteful individuals, which can eventually undermine cooperation. Using two large-scale experiments, this note explores the nature of Ultimatum Game punishers by analyzing their behavior in a Dictator Game. In both studies, the coexistence of two entirely different sub-populations is confirmed: prosocial punishers on the one hand, who behave fairly as dictators, and spiteful (antisocial) punishers on the other, who are totally unfair. The finding has important implications regarding the evolution of cooperation and the behavioral underpinnings of stable social systems. PMID:25113502

  12. Adult-onset Nemaline Myopathy Coexisting With Myasthenia Gravis

    Science.gov (United States)

    Cao, Lingling; Wang, Yanling; Liu, Xiaofeng; Hu, Yanxia; Li, Nianchun; Qiu, Guoping; Luo, Yun; Li, Weidong

    2016-01-01

    Abstract Myasthenia gravis (MG) is an autoimmune neuromuscular junction disorder which is characterized by fluctuating muscle fatigue. However, the association of MG with nemaline myopathy is rarely reported. Here we report a case of MG coexisting with adult-onset nemaline myopathy. A 55-year-old man endured fluctuating muscle weakness with positive acetylcholine receptor and titin antibodies. After the patient was administrated cholinergic drugs and immunosuppression, the muscle weakness of the patient had mildly been alleviated. Electromyography showed a progressive decrement in the amplitude of muscle action potential at low frequency. Muscle biopsy showed numerous nemalines in the muscle fibers. This is the first reported case of nemalines present in the muscle fibers of adult patient with MG. The pathogenesis of nemaline may be related to titin antibody in adult-onset nemaline myopathy with MG. PMID:26825889

  13. Two Coexisting Liquid Phases in Switchable Ionic Liquids

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Juan; Lao, David; Sui, Xiao; Zhou, Yufan; Nune, Satish K.; Ma, Xiang; Troy, Tyler; Ahmed, Musahid; Zhu, Zihua; Heldebrant, David J.; Yu, Xiao-Ying

    2017-08-30

    In situ time-of-flight secondary ion mass spectrometry (ToF-SIMS) coupled with a vacuum compatible microfluidic reactor, System for Analysis at Liquid Vacuum Interface (SALVI), has enabled the first spatial mapping of the switchable ionic liquids (SWILs) derived from 1,8-diazabicycloundec-7-ene (DBU) and 1-hexanol. As predicted by molecular dynamic simulations, our molecular imaging results confirmed a dynamic heterogeneous molecular structure with ionic regions (high CO2 concentration) coexisting with non-ionic regions (no CO2) where stoichiometry would indicate otherwise. Chemical speciation was also found to be more complex than initially thought, with spectral principal component analysis identifying dimers that ultimately highlight a highly complex molecular structure unique to SWILs. The spatial chemical mapping enabled by ToF-SIMS and SALVI advances the understanding of how the heterogeneous molecular structure impacts the dynamic physical and thermodynamic properties or SWILs.

  14. Moyamoya Disease with Coexistent Hypertriglyceridemia in Pediatric Patient

    Science.gov (United States)

    Sahni, Deepank; Boucher-Berry, Claudia

    2016-01-01

    Moyamoya disease is a rare chronic and progressive cerebrovascular disease of the arteries of the circle of Willis that can affect children and adults. It has been associated with multiple diseases, including immunologic, like Graves' disease, diabetes mellitus, and SLE. Hyperlipidemia has been recognized in patients with Moyamoya disease with an incidence of 27–37%. However, no case in pediatric patients has been reported of the coexistence of Moyamoya disease and hyperlipidemia. Here we present a case of a 9-year-old female diagnosed with Moyamoya disease after a stroke with incidental finding of familial hypercholesterolemia. This finding will make our patient a very unique case, since there has not been any reporting of Moyamoya disease and hypercholesterolemia association. PMID:27843655

  15. Moyamoya Disease with Coexistent Hypertriglyceridemia in Pediatric Patient

    Directory of Open Access Journals (Sweden)

    Jacqueline Chan

    2016-01-01

    Full Text Available Moyamoya disease is a rare chronic and progressive cerebrovascular disease of the arteries of the circle of Willis that can affect children and adults. It has been associated with multiple diseases, including immunologic, like Graves’ disease, diabetes mellitus, and SLE. Hyperlipidemia has been recognized in patients with Moyamoya disease with an incidence of 27–37%. However, no case in pediatric patients has been reported of the coexistence of Moyamoya disease and hyperlipidemia. Here we present a case of a 9-year-old female diagnosed with Moyamoya disease after a stroke with incidental finding of familial hypercholesterolemia. This finding will make our patient a very unique case, since there has not been any reporting of Moyamoya disease and hypercholesterolemia association.

  16. Coexisting ipsilateral right femoral hernia and incarcerated obturator hernia.

    Science.gov (United States)

    Seppälä, Toni T; Tuuliranta, Mikko

    2015-02-25

    Obturator hernia (OH) is an uncommon cause of bowel obstruction and described in elderly females in the literature. The treatment has traditionally been laparotomy because of an acute nature of the condition. However, because of old age and comorbidities that OH is associated with, general anaesthesia may need to be avoided. In the current case, a transinguinal preperitoneal approach and management are presented after delayed preoperative diagnosis of bowel obstruction caused by a coexisting right incarcerated OH and ipsilateral non-reducible femoral hernia. A 91-year-old woman had a 6-day history of nausea and vomiting. She was referred to surgery because of persisting vomiting, but without any abdominal pain. A CT scan showed a hernia in the right groin area but the diagnosis was delayed. The hernias were repaired using a preperitoneal transinguinal approach. Bowel resection was not needed. The obturator canal and the femoral ring were both covered by a Bard Polysoft patch.

  17. 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.

  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. Climate and local abundance in freshwater fishes

    OpenAIRE

    Knouft, Jason H.; Anthony, Melissa M.

    2016-01-01

    Identifying factors regulating variation in numbers of individuals among populations across a species' distribution is a fundamental goal in ecology. A common prediction, often referred to as the abundant-centre hypothesis, suggests that abundance is highest near the centre of a species' range. However, because of the primary focus on the geographical position of a population, this framework provides little insight into the environmental factors regulating local abundance. While range-wide va...

  20. Interactions among coexisting predators: a field experiment with dragonfly larvae

    Energy Technology Data Exchange (ETDEWEB)

    Benke, A.C.

    1978-06-01

    Larval dragonfly populations were manipulated in large littoral zone enclosures to determine the importance of inter-odonate interactions and the effects of dragonflies on their prey. Initial densities of early emerging odonate cohorts were about six times greater in one group of pens than in others. When initial densities were low, survivorship was higher and growth appeared to be faster than when initial densities were high. Highly significant differences of early species densities were maintained between treatment pens during the 6-month experimental period. Early emerging odonates had a highly significant influence on the abundance of the smaller, late emerging odonates, indicating a strong interaction between odonate species. The interaction appeared to be due to predation by large odonates on small odonates. This is interpreted as an extreme form of interference competition which plays an important role in odonate population regulation. Although there was a large treatment bias in prey species abundance, the results indicate that abundance of early emerging odonates plays some role in prey (especially Tanypodinae) abundance. It is suggested that the primary determinant of community structure and production is an interaction between refuge level and predation rate. It is necessary for prey to be turning over at an unusually high rate and it is possible that odonates function in stimulating the rate of prey production.

  1. Abundance of introduced species at home predicts abundance away in herbaceous communities

    Science.gov (United States)

    Firn, Jennifer; Moore, Joslin L.; MacDougall, Andrew S.; Borer, Elizabeth T.; Seabloom, Eric W.; HilleRisLambers, Janneke; Harpole, W. Stanley; Cleland, Elsa E.; Brown, Cynthia S.; Knops, Johannes M.H.; Prober, Suzanne M.; Pyke, David A.; Farrell, Kelly A.; Bakker, John D.; O'Halloran, Lydia R.; Adler, Peter B.; Collins, Scott L.; D'Antonio, Carla M.; Crawley, Michael J.; Wolkovich, Elizabeth M.; La Pierre, Kimberly J.; Melbourne, Brett A.; Hautier, Yann; Morgan, John W.; Leakey, Andrew D.B.; Kay, Adam; McCulley, Rebecca; Davies, Kendi F.; Stevens, Carly J.; Chu, Cheng-Jin; Holl, Karen D.; Klein, Julia A.; Fay, Phillip A.; Hagenah, Nicole; Kirkman, Kevin P.; Buckley, Yvonne M.

    2011-01-01

    Many ecosystems worldwide are dominated by introduced plant species, leading to loss of biodiversity and ecosystem function. A common but rarely tested assumption is that these plants are more abundant in introduced vs. native communities, because ecological or evolutionary-based shifts in populations underlie invasion success. Here, data for 26 herbaceous species at 39 sites, within eight countries, revealed that species abundances were similar at native (home) and introduced (away) sites - grass species were generally abundant home and away, while forbs were low in abundance, but more abundant at home. Sites with six or more of these species had similar community abundance hierarchies, suggesting that suites of introduced species are assembling similarly on different continents. Overall, we found that substantial changes to populations are not necessarily a pre-condition for invasion success and that increases in species abundance are unusual. Instead, abundance at home predicts abundance away, a potentially useful additional criterion for biosecurity programmes.

  2. Co-existence of Anaerobic Ammonium Oxidation Bacteria and Denitrifying Anaerobic Methane Oxidation Bacteria in Sewage Sludge: Community Diversity and Seasonal Dynamics

    DEFF Research Database (Denmark)

    Xu, Sai; Lu, Wenjing; Mustafa, Muhammad Farooq

    2017-01-01

    , and an unknown cluster was primarily detected in autumn and winter. Similar patterns of seasonal variation in the community structure of DAMO bacteria were also observed. Group B was the dominant in spring and summer, whereas in autumn and winter, group A and group B presented almost the same proportion...... and their abundance in sewage sludge collected from wastewater treatment plants were analysed. Results indicated that ANAMMOX and DAMO bacteria co-existed in sewage sludge in different seasons and their abundance was positively correlated (P bacteria in autumn and winter...... indicated that these seasons were the preferred time to favour the growth of ANAMMOX and DAMO bacteria. The community structure of ANNAMOX and DAMO bacteria could also shift with seasonal changes. The “Candidatus Brocadia� genus of ANAMMOX bacteria was mainly recovered in spring and summer...

  3. Coexistence in the two-dimensional May-Leonard model with random rates

    Science.gov (United States)

    He, Q.; Mobilia, M.; Täuber, U. C.

    2011-07-01

    We employ Monte Carlo simulations to numerically study the temporal evolution and transient oscillations of the population densities, the associated frequency power spectra, and the spatial correlation functions in the (quasi-) steady state in two-dimensional stochastic May-Leonard models of mobile individuals, allowing for particle exchanges with nearest-neighbors and hopping onto empty sites. We therefore consider a class of four-state three-species cyclic predator-prey models whose total particle number is not conserved. We demonstrate that quenched disorder in either the reaction or in the mobility rates hardly impacts the dynamical evolution, the emergence and structure of spiral patterns, or the mean extinction time in this system. We also show that direct particle pair exchange processes promote the formation of regular spiral structures. Moreover, upon increasing the rates of mobility, we observe a remarkable change in the extinction properties in the May-Leonard system (for small system sizes): (1) as the mobility rate exceeds a threshold that separates a species coexistence (quasi-) steady state from an absorbing state, the mean extinction time as function of system size N crosses over from a functional form ˜ e c N / N (where c is a constant) to a linear dependence; (2) the measured histogram of extinction times displays a corresponding crossover from an (approximately) exponential to a Gaussian distribution. The latter results are found to hold true also when the mobility rates are randomly distributed.

  4. 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.

  5. Health Promotion

    DEFF Research Database (Denmark)

    Povlsen, Lene; Borup, I.

    2015-01-01

    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...... - an associate professorship was established with a focus on health promotion. Nevertheless, the concept of health promotion had been integrated with or mentioned in courses run prior to the new post. Subsequently, a wide spectrum of courses in health promotion was introduced, such as Empowerment for Child...

  6. 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

  7. The Costs of Coexistence Measures for Genetically Modified Maize in Germany

    DEFF Research Database (Denmark)

    Venus, Thomas J.; Dillen, Koen; Punt, Maarten J.

    2017-01-01

    We estimate the perceived costs of legal requirements ('coexistence measures') for growing genetically modified (GM) Bt maize in Germany using a choice experiment. The costs of the evaluated ex-ante and ex-post coexistence measures range from zero to more than €300 per measure and most are greate...

  8. 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

  9. Coexistence between conventional, organic and GM crops production: the Portuguese system.

    Science.gov (United States)

    Chiarabolli, Alessandro

    2011-01-01

    The objective of this paper is to analyze the way of Portugal is addressing the issue of the coexistence between conventional, organic and Genetically Modified (GM) crops production. In the EU, no form of agriculture, be it conventional, organic or transgenic, should be excluded. Farmers are free to choose the production type they prefer, without being forced to change patterns already established in the area and without spending more resources. Farmers' choice of growing GM or non-GM crops depends not only on technical aspects related to the productivity gains and agronomic benefits to be gained from adopting this technology, but also on consumers' preferences. Today only few Member States have adopted specific legislation on coexistence. Portugal was one of the first European Country that, in 2005, adopted a coexistence law and it has implemented one of the most complete systems of coexistence regulation. Today Portugal has a well-balanced regime based on free choice for consumers and growers. It has a coexistence system complete regulation and farmers who wish to cultivate GM maize must fulfill with national coexistence legislation that includes the following compulsory rules: participate in specific coexistence training courses, register the cultivation area, inform by written notification about their intent to cultivate GM, apply measures of coexistence, among others.

  10. Colourful coexistence of red and green picocyanobacteria in lakes and seas

    NARCIS (Netherlands)

    Stomp, M.; Huisman, J.; Pick, F.R.; Laamanen, M.; Haverkamp, T.H.A.; Stal, L.J.

    2007-01-01

    Hutchinson’s paradox of the plankton inspired many studies on the mechanisms of species coexistence. Recent laboratory experiments showed that partitioning of white light allows stable coexistence of red and green picocyanobacteria. Here, we investigate to what extent these laboratory findings can b

  11. Colourful coexistence of red and green picocyanobacteria in lakes and seas

    NARCIS (Netherlands)

    Stomp, M.; Huisman, J.; Vörös, L.; Pick, F.R.; Laamanen, M.; Haverkamp, T.H.A.; Stal, L.J.

    2007-01-01

    Hutchinson's paradox of the plankton inspired many studies on the mechanisms of species coexistence. Recent laboratory experiments showed that partitioning of white light allows stable coexistence of red and green picocyanobacteria. Here, we investigate to what extent these laboratory findings can b

  12. Coexistence of density wave and superfluid order in a dipolar Fermi gas

    DEFF Research Database (Denmark)

    Wu, Zhigang; Block, Jens Kusk; Bruun, Georg M.

    2015-01-01

    We analyse the coexistence of superfluid and density wave (stripe) order in a quasi-two-dimensional gas of dipolar fermions aligned by an external field. Remarkably, the anisotropic nature of the dipolar interaction allows for such a coexistence in a large region of the zero temperature phase dia...

  13. Quark Transport Properties in the Region of Coexistence of Both Hadronic and QGP Phases

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiang-Jun; LI Hong; WANG Gang; ZHANG Wei-Ning; HUO Lei

    2001-01-01

    The physical picture of coexistence of both hadronic and QGP phases is given by Friedberg and T.D. Lee's nontopology soliton model. The transport properties of quark in color space and spin space in a system of two-phase coexistence are investigated from both quantum and classical theories.

  14. Complexity and coexistence in a simple spatial model for arid savanna ecosystems

    NARCIS (Netherlands)

    Baudena, M.; Rietkerk, M.

    2012-01-01

    Tree–grass coexistence is broadly observed in tropical savannas. Recent studies indicate that, in arid savannas, such coexistence is stable and related to water availability. The role of different factors (from niche separation to demographic structure) has been explored. Nevertheless, spatial mecha

  15. Cascading effects of defaunation on the coexistence of two specialized insect seed predators

    NARCIS (Netherlands)

    Peguero, Guille; Muller-Landau, Helene C.; Jansen, Patrick A.; Wright, S.J.

    2017-01-01

    Identification of the mechanisms enabling stable coexistence of species with similar resource requirements is a central challenge in ecology. Such coexistence can be facilitated by species at higher trophic levels through complex multi-trophic interactions, a mechanism that could be compromised b

  16. Moral Education and Improvement of Coexistence in Secondary Education (12-16 Years) in Spain

    Science.gov (United States)

    Rodriguez-Conde, M. J.; Olmos Miguelanez, S.; Perochena Gonzalez, P.; Herrera Garcia, E.

    2011-01-01

    Coexistence and moral education are areas of great interest in Spanish compulsory education, especially in the period that comprises between 12 and 16 years of age, named "compulsory secondary education" in Spain. With the aim to improve the processes of coexistence within this level, this research team on education from the University…

  17. The Coexistence Claim and Its Possible Implications for Success in Teaching for Conceptual "Change"

    Science.gov (United States)

    Potvin, Patrice

    2017-01-01

    This article presents recent research results in mental chronometry and neuroimaging that support the coexistence of multiple conceptions. It then presents and elaborates on six possible implications for an adherence to the coexistence claim within the context of scientific conceptual learning: (1) stop the war on misconceptions; (2) use a…

  18. 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...

  19. The coexistence of hosts with different abilities to discriminate against cheater partners: an evolutionary game-theory approach.

    Science.gov (United States)

    Steidinger, Brian S; Bever, James D

    2014-06-01

    Evolutionary theory predicts that mutualisms based on the reciprocal exchange of costly services should be susceptible to exploitation by cheaters. Consistent with theory, both cheating and discrimination against cheaters are ubiquitous features of mutualisms. Several recent studies have confirmed that host species differ in the extent that they are able to discriminate against cheaters, suggesting that cheating may be stabilized by the existence of susceptible hosts (dubbed "givers"). We use an evolutionary game-theoretical approach to demonstrate how discriminating and giver hosts associating with mutualist and cheater partners can coexist. Discriminators drive the proportion of cheaters below a critical threshold, at which point there is no benefit to investing resources into discrimination. This promotes givers, who benefit from mutualists but allow cheater populations to rebound. We then apply this model to the plant-mycorrhizal mutualism and demonstrate it is one mechanism for generating host-specific responses to mycorrhizal fungal species necessary to generate negative plant-soil feedbacks. Our model makes several falsifiable, qualitative predictions for plant-mycorrhizal population dynamics across gradients of soil phosphorus availability and interhost differences in ability to discriminate. Finally, we suggest applications and limitations of the model with regard to coexistence in specific biological systems.

  20. Microbial mat controls on infaunal abundance and diversity in modern marine microbialites.

    Science.gov (United States)

    Tarhan, L G; Planavsky, N J; Laumer, C E; Stolz, J F; Reid, R P

    2013-09-01

    Microbialites are the most abundant macrofossils of the Precambrian. Decline in microbialite abundance and diversity during the terminal Proterozoic and early Phanerozoic has historically been attributed to the concurrent radiation of complex metazoans. Similarly, the apparent resurgence of microbialites in the wake of Paleozoic and Mesozoic mass extinctions is frequently linked to drastic declines in metazoan diversity and abundance. However, it has become increasing clear that microbialites are relatively common in certain modern shallow, normal marine carbonate environments-foremost the Bahamas. For the first time, we present data, collected from the Exuma Cays, the Bahamas, systematically characterizing the relationship between framework-building cyanobacteria, microbialite fabrics, and microbialite-associated metazoan abundance and diversity. We document the coexistence of diverse microbialite and infaunal metazoan communities and demonstrate that the predominant control upon both microbialite fabric and metazoan community structure is microbial mat type. These findings necessitate that we rethink prevalent interpretations of microbialite-metazoan interactions and imply that microbialites are not passive recipients of metazoan-mediated alteration. Additionally, this work provides support for the theory that certain Precambrian microbialites may have been havens of early complex metazoan life, rather than bereft of metazoans, as has been traditionally envisaged. © 2013 John Wiley & Sons Ltd.

  1. Are the Formation and Abundances of Metal-Poor Stars the Result of Dust Dynamics?

    CERN Document Server

    Hopkins, Philip F

    2015-01-01

    Large dust grains can fluctuate dramatically in their local density, relative to gas, in neutral, turbulent disks. Small, high-redshift galaxies (before reionization) represent ideal environments for this process. We show via simple arguments and simulations that order-of-magnitude fluctuations are expected in local abundances of large grains under these conditions. This can have important consequences for star formation and stellar abundances in extremely metal-poor stars. Low-mass stars could form in dust-enhanced regions almost immediately after some dust forms, even if the galaxy-average metallicity is too low for fragmentation to occur. The abundances of these 'promoted' stars may contain interesting signatures, as the CNO abundances (concentrated in large carbonaceous grains and ices) and Mg and Si (in large silicate grains) can be enhanced or fluctuate independently. Remarkably, otherwise puzzling abundance patterns of some metal-poor stars can be well-fit by standard core-collapse SNe yields, if we al...

  2. Coexistence of congeneric native and invasive species: the case of the green algae Codium spp. in northwestern Spain.

    Science.gov (United States)

    Rojo, Irene; Olabarria, Celia; Santamaria, Marta; Provan, Jim; Gallardo, Tomás; Viejo, Rosa M

    2014-10-01

    We examined the patterns of distribution and abundance, and reproductive traits (presence of gametophytes and size at time of reproduction) in the invasive Codium fragile ssp. fragile and the native C. tomentosum and C. vermilara on intertidal habitats of NW Spain at two dates. All three species coexist in the locations and habitats studied, although abundances were low. We found a greater proportion of C. fragile ssp. fragile towards the east of the Cantabrian coast and on upper levels on the shore, where conditions are more stressful. The proportion of thalli bearing gametangia in C. fragile ssp. fragile was greater than in the native species in all habitats. The presence of gametangia was size-dependent for all species, with the invasive species maturing at a smaller size, which combined with the previous features, might confer competitive advantages to this species over the native species. We also demonstrated that molecular analyses are necessary for the correct identification of C. fragile subspecies.

  3. Diversity and abundance of ammonia-oxidizing

    NARCIS (Netherlands)

    Cardoso, J.F.M.F.; van Bleijswijk, J.D.L.; Witte, H.; van Duyl, F.C.

    2013-01-01

    We analysed the diversity and abundance of ammonia-oxidizing Archaea (AOA) and Bacteria (AOB) in the shallow warm-water sponge Halisarca caerulea and the deep cold-water sponges Higginsia thielei and Nodastrella nodastrella. The abundance of AOA and AOB was analysed using catalyzed reporter

  4. Climate and local abundance in freshwater fishes.

    Science.gov (United States)

    Knouft, Jason H; Anthony, Melissa M

    2016-06-01

    Identifying factors regulating variation in numbers of individuals among populations across a species' distribution is a fundamental goal in ecology. A common prediction, often referred to as the abundant-centre hypothesis, suggests that abundance is highest near the centre of a species' range. However, because of the primary focus on the geographical position of a population, this framework provides little insight into the environmental factors regulating local abundance. While range-wide variation in population abundance associated with environmental conditions has been investigated in terrestrial species, the relationship between climate and local abundance in freshwater taxa across species' distributions is not well understood. We used GIS-based temperature and precipitation data to determine the relationships between climatic conditions and range-wide variation in local abundance for 19 species of North American freshwater fishes. Climate predicted a portion of the variation in local abundance among populations for 18 species. In addition, the relationship between climatic conditions and local abundance varied among species, which is expected as lineages partition the environment across geographical space. The influence of local habitat quality on species persistence is well documented; however, our results also indicate the importance of climate in regulating population sizes across a species geographical range, even in aquatic taxa.

  5. Abundant Semigroups with a Multiplicative Adequate Transversal

    Institute of Scientific and Technical Information of China (English)

    GUO Xiao Jiang

    2002-01-01

    The aim of this paper is to investigate abundant semigroups with a multiplicative adequate transversal. Some properties and characterizations for such semigroups are obtained. In particular,we establish the structure of this class of abundant semigroups in terms of left normal bands, right normal bands and adequate semigroups with some simple compatibility conditions. Finally, we apply this structure to some special cases.

  6. Diversity and abundance of ammonia-oxidizing

    NARCIS (Netherlands)

    Cardoso, J.F.M.F.; van Bleijswijk, J.D.L.; Witte, H.; van Duyl, F.C.

    2013-01-01

    We analysed the diversity and abundance of ammonia-oxidizing Archaea (AOA) and Bacteria (AOB) in the shallow warm-water sponge Halisarca caerulea and the deep cold-water sponges Higginsia thielei and Nodastrella nodastrella. The abundance of AOA and AOB was analysed using catalyzed reporter depositi

  7. Resource Abundance and Resource Dependence in China

    NARCIS (Netherlands)

    Ji, K.; Magnus, J.R.; Wang, W.

    2010-01-01

    This paper reconsiders the ‘curse of resources’ hypothesis for the case of China, and distinguishes between resource abundance, resource rents, and resource dependence. Resource abundance and resource rents are shown to be approximately equivalent, and their association with resource dependence vari

  8. On the Solar Nickel and Oxygen Abundances

    Science.gov (United States)

    Scott, Pat; Asplund, Martin; Grevesse, Nicolas; Sauval, A. Jacques

    2009-02-01

    Determinations of the solar oxygen content relying on the neutral forbidden transition at 630 nm depend upon the nickel abundance, due to a Ni I blend. Here, we rederive the solar nickel abundance, using the same ab initio three-dimensional hydrodynamic model of the solar photosphere employed in the recent revision of the abundances of C, N, O, and other elements. Using 17 weak, unblended lines of Ni I together with the most accurate atomic and observational data available, we find log epsilonNi = 6.17 ± 0.02(statistical) ± 0.05(systematic), a downward shift of 0.06-0.08 dex relative to previous abundances based on one-dimensional model atmospheres. We investigate the implications of the new nickel abundance for studies of the solar oxygen abundance based on the [O I] 630 nm line in the quiet Sun. Furthermore, we demonstrate that the oxygen abundance implied by the recent sunspot spectropolarimetric study of Centeno & Socas-Navarro needs to be revised downward from log epsilonO = 8.86 ± 0.07 to 8.71 ± 0.10. This revision is based on the new nickel abundance, the application of the best available gf value for the 630 nm forbidden oxygen line, and a more transparent treatment of CO formation. Determinations of the solar oxygen content relying on forbidden lines now appear to converge around log epsilonO = 8.7.

  9. Diversity and abundance of ammonia-oxidizing

    NARCIS (Netherlands)

    Cardoso, J.F.M.F.; van Bleijswijk, J.D.L.; Witte, H.; van Duyl, F.C.

    2013-01-01

    We analysed the diversity and abundance of ammonia-oxidizing Archaea (AOA) and Bacteria (AOB) in the shallow warm-water sponge Halisarca caerulea and the deep cold-water sponges Higginsia thielei and Nodastrella nodastrella. The abundance of AOA and AOB was analysed using catalyzed reporter depositi

  10. 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

  11. 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

  12. The coexistence of alternative and scientific conceptions in physics

    Science.gov (United States)

    Ozdemir, Omer F.

    The purpose of this study was to inquire about the simultaneous coexistence of alternative and scientific conceptions in the domain of physics. This study was particularly motivated by several arguments put forward in opposition to the Conceptual Change Model. In the simplest form, these arguments state that people construct different domains of knowledge and different modes of perception in different situations. Therefore, holding different conceptualizations is unavoidable and expecting a replacement in an individual's conceptual structure is not plausible in terms of instructional practices. The following research questions were generated to inquire about this argument: (1) Do individuals keep their alternative conceptions after they have acquired scientific conceptions? (2) Assuming that individuals who acquired scientific conceptions also have alternative conceptions, how are these different conceptions nested in their conceptual structure? (3) What kind of knowledge, skills, and reasoning are necessary to transfer scientific principles instead of alternative ones in the construction of a valid model? Analysis of the data collected from the non-physics group indicated that the nature of alternative conceptions is framed by two types of reasoning: reasoning by mental simulation and semiformal reasoning. Analysis of the data collected from the physics group revealed that mental images or scenes feeding reasoning by mental simulation had not disappeared after the acquisition of scientific conceptions. The analysis of data also provided enough evidence to conclude that alternative principles feeding semiformal reasoning have not necessarily disappeared after the acquisition of scientific conceptions. However, in regard to semiformal reasoning, compartmentalization was not as clear as the case demonstrated in reasoning by mental simulation; instead semiformal and scientific reasoning are intertwined in a way that the components of semiformal reasoning can easily

  13. Modelling Water Uptake Provides a New Perspective on Grass and Tree Coexistence.

    Science.gov (United States)

    Mazzacavallo, Michael G; Kulmatiski, Andrew

    2015-01-01

    Root biomass distributions have long been used to infer patterns of resource uptake. These patterns are used to understand plant growth, plant coexistence and water budgets. Root biomass, however, may be a poor indicator of resource uptake because large roots typically do not absorb water, fine roots do not absorb water from dry soils and roots of different species can be difficult to differentiate. In a sub-tropical savanna, Kruger Park, South Africa, we used a hydrologic tracer experiment to describe the abundance of active grass and tree roots across the soil profile. We then used this tracer data to parameterize a water movement model (Hydrus 1D). The model accounted for water availability and estimated grass and tree water uptake by depth over a growing season. Most root biomass was found in shallow soils (0-20 cm) and tracer data revealed that, within these shallow depths, half of active grass roots were in the top 12 cm while half of active tree roots were in the top 21 cm. However, because shallow soils provided roots with less water than deep soils (20-90 cm), the water movement model indicated that grass and tree water uptake was twice as deep as would be predicted from root biomass or tracer data alone: half of grass and tree water uptake occurred in the top 23 and 43 cm, respectively. Niche partitioning was also greater when estimated from water uptake rather than tracer uptake. Contrary to long-standing assumptions, shallow grass root distributions absorbed 32% less water than slightly deeper tree root distributions when grasses and trees were assumed to have equal water demands. Quantifying water uptake revealed deeper soil water uptake, greater niche partitioning and greater benefits of deep roots than would be estimated from root biomass or tracer uptake data alone.

  14. 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.

  15. Coexistence of gastrointestinal stromal tumor, esophageal and gastric cardia carcinomas.

    Science.gov (United States)

    Zhou, Yong; Wu, Xu-Dong; Shi, Quan; Jia, Jing

    2013-03-28

    Gastric gastrointestinal stromal tumor (GIST), esophageal squamous cell carcinoma and gastric cardia adenocarcinoma are distinct neoplasms originating from different cell layers; therefore, simultaneous development of such carcinomas is relatively rare. Auxiliary examinations revealed coexistence of esophageal and gastric cardia carcinoma with lymph node metastasis in a 77-year-old man. Intraoperatively, an extraluminal tumor (about 6.0 cm × 5.0 cm × 6.0 cm) at the posterior wall of the gastric body, a tumor (about 2.5 cm × 2.0 cm) in the lower esophagus, and an infiltrative and stenosing tumor (about 1.0 cm × 2.0 cm) in the gastric cardia were detected. Wedge resection for extraluminal gastric tumor, radical esophagectomy for lower esophageal tumor, and cardiac resection with gastroesophageal (supra-aortic arch anastomoses) were performed. Postoperative histological examination showed synchronous occurrence of gastric GIST, esophageal squamous cell carcinoma, and gastric cardia adenocarcinoma. Furthermore, immunohistochemistry indicated strong staining for c-Kit/CD117, Dog-1, Ki-67 and smooth muscle, while expression of S-100 and CD34 was negative.

  16. Genes and processed paralogs co-exist in plant mitochondria.

    Science.gov (United States)

    Cuenca, Argelia; Petersen, Gitte; Seberg, Ole; Jahren, Anne Hoppe

    2012-04-01

    RNA-mediated gene duplication has been proposed to create processed paralogs in the plant mitochondrial genome. A processed paralog may retain signatures left by the maturation process of its RNA precursor, such as intron removal and no need of RNA editing. Whereas it is well documented that an RNA intermediary is involved in the transfer of mitochondrial genes to the nucleus, no direct evidence exists for insertion of processed paralogs in the mitochondria (i.e., processed and un-processed genes have never been found simultaneously in the mitochondrial genome). In this study, we sequenced a region of the mitochondrial gene nad1, and identified a number of taxa were two different copies of the region co-occur in the mitochondria. The two nad1 paralogs differed in their (a) presence or absence of a group II intron, and (b) number of edited sites. Thus, this work provides the first evidence of co-existence of processed paralogs and their precursors within the plant mitochondrial genome. In addition, mapping the presence/absence of the paralogs provides indirect evidence of RNA-mediated gene duplication as an essential process shaping the mitochondrial genome in plants.

  17. COEXISTENCE YELLOW NAIL SYNDROME WITH SYSTEMIC SYMPTOMS - PRESENTATION OF CASES

    Directory of Open Access Journals (Sweden)

    Brzeziński Piotr

    2010-10-01

    Full Text Available Nail changes can accompany many systemic diseases and very often indicate the ongoing systemic process of illness. The yellow nail syndrome (YNS is very rare clinical entity characterized by marked thickening and yellow to yellow-green discoloration of the nails. Congenitally hypoplastic lymphostasis plays a major role in the clinical manifestation of that disease. Syndrome includes pleural effusions, lymphedema and yellow dystrophic nails. The pathogenesis stays still unknown.Aim: Presentation the coexistence of YNS with the systemic symptoms by analyzing cases of 3 patients.Material and methods: The analysis involved 3 patients with YNS (2 women and 1 man aged from 43 to 48 years.Results: We confirmed 3 cases of YNS, with the characteristic nails changes (yellow-greenish discoloration, absence of lunula, etc.. None of the patients had a family history of YNS. All suffered from chronic diseases: the first patient suffered from lymphedema and diabetes mellitus, second - from rheumatoid arthritis and the third complained of a chronic caught and sinusitis. All YNS`s symptoms occurred in the patients` forties. We observed fingers and toes involvement on 7-8 nails in each patient.Conclusions: The YNS offen associated with systemic disease, most commonly lymphedema and bronchiectasis. However, the literature describes some connections with carcinoma and autoimmune diseases. Therefore, each patient with YNS should be examined for cancer detection and stay under periodic medical control.

  18. Fluctuations-induced coexistence in public goods dynamics

    Science.gov (United States)

    Behar, H.; Brenner, N.; Ariel, G.; Louzoun, Y.

    2016-10-01

    Cooperative interactions between individuals in a population and their stability properties are central to population dynamics and evolution. We introduce a generic class of nonlinear dynamical systems describing such interactions between producers and non-producers of a rapidly equilibrating common resource extracted from a finite environment. In the deterministic mean field approximation, fast-growing non-producers drive the entire population to extinction. However, the presence of arbitrarily small perturbations destabilizes this fixed point into a stochastic attractor where both phenotypes can survive. Phase space arguments and moment closure are used to characterize the attractor and show that its properties are not determined by the noise amplitude or boundary conditions, but rather it is stabilized by the stochastic nonlinear dynamics. Spatial Monte Carlo simulations with demographic fluctuations and diffusion illustrate a similar effect, supporting the validity of the two-dimensional stochastic differential equation as an approximation. The functional distribution of the noise emerges as the main factor determining the dynamical outcome. Noise resulting from diffusion between different regions, or additive noise, induce coexistence while multiplicative or local demographic noise do not alter the outcome of deterministic dynamics. The results are discussed in a general context of the effect of noise on phase space structure.

  19. 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.

  20. Coexistent of paradoxical herniation and subdural hygroma: a case report

    Institute of Scientific and Technical Information of China (English)

    Yi Feng; Yuhai Wang

    2015-01-01

    Background: Coexistent of paradoxical herniation and subdural hygroma (SDG) is very rare, confusing symptoms may mislead the therapies.Case presentation: We report a case of a 33-year-old man underwent decompressive craniectomy (DC),postoperatively, the patient developed progressive neurologic deterioration and midline shift opposite to the DC window, CT scan revealed a SDG beside the DC window, instead of attributing the midline shift to the SDG, we recognized the underlying paradoxical herniation according to the sunken skin flap and history of lumbar cistern drainage.Subsequently we treat him with intravenous fluid expansion therapy instead of draining from the SDG, the patient recovered in one day and no recurrence was found later.Conclusion: For patients underwent DC, we should pay attention to the occurrence of paradoxicalherniation, SDG following DC may be the consequence of paradoxical herniation caused by CSF reduce therapy in post-DC patient, intravenous fluid expansion therapy is recommended and would play a great role for the recovery of the patient rather than surgical management.

  1. Coexisting cytomegalovirus infection in immunocompetent patients with Clostridium difficile colitis.

    Science.gov (United States)

    Chan, Khee-Siang; Lee, Wen-Ying; Yu, Wen-Liang

    2016-12-01

    Cytomegalovirus (CMV) colitis usually occurs in immunocompromised patients with human immunodeficiency virus infection, organ transplantation, and malignancy receiving chemotherapy or ulcerative colitis receiving immunosuppressive agents. However, CMV colitis is increasingly recognized in immunocompetent hosts. Notably, CMV colitis coexisting with Clostridium difficile infection (CDI) in apparently healthy individuals has been published in recent years, which could result in high morbidity and mortality. CMV colitis is a rare but possible differential diagnosis in immunocompetent patients with abdominal pain, watery, or especially bloody diarrhea, which could be refractory to standard treatment for CDI. As a characteristic of CDI, however, pseudomembranous colitis may be only caused by CMV infection. Real-time CMV-polymerase chain reaction (PCR) for blood and stool samples may be a useful and noninvasive diagnostic strategy to identify CMV infection when treatment of CDI eventually fails to show significant benefits. Quantitative CMV-PCR in mucosal biopsies may increase the diagnostic yield of traditional histopathology. CMV colitis is potentially life-threatening if severe complications occur, such as sepsis secondary to colitis, massive colorectal bleeding, toxic megacolon, and colonic perforation, so that may necessitate pre-emptive antiviral treatment for those who are positive for CMV-PCR in blood and/or stool samples while pending histological diagnosis.

  2. 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.

  3. Hierarchical ferroelectric and ferrotoroidic polarizations coexistent in nano-metamaterials.

    Science.gov (United States)

    Shimada, Takahiro; Lich, Le Van; Nagano, Koyo; Wang, Jie; Kitamura, Takayuki

    2015-10-01

    Tailoring materials to obtain unique, or significantly enhanced material properties through rationally designed structures rather than chemical constituents is principle of metamaterial concept, which leads to the realization of remarkable optical and mechanical properties. Inspired by the recent progress in electromagnetic and mechanical metamaterials, here we introduce the concept of ferroelectric nano-metamaterials, and demonstrate through an experiment in silico with hierarchical nanostructures of ferroelectrics using sophisticated real-space phase-field techniques. This new concept enables variety of unusual and complex yet controllable domain patterns to be achieved, where the coexistence between hierarchical ferroelectric and ferrotoroidic polarizations establishes a new benchmark for exploration of complexity in spontaneous polarization ordering. The concept opens a novel route to effectively tailor domain configurations through the control of internal structure, facilitating access to stabilization and control of complex domain patterns that provide high potential for novel functionalities. A key design parameter to achieve such complex patterns is explored based on the parity of junctions that connect constituent nanostructures. We further highlight the variety of additional functionalities that are potentially obtained from ferroelectric nano-metamaterials, and provide promising perspectives for novel multifunctional devices. This study proposes an entirely new discipline of ferroelectric nano-metamaterials, further driving advances in metamaterials research.

  4. Temporal segregation in coexisting Acomys species: the role of odour.

    Science.gov (United States)

    Haim, A; Rozenfeld, F M

    1993-12-01

    To understand the mechanisms underlying displacement (the shift from nocturnal to diurnal activity), in one of the two coexisting spiny mice (genus Acomys), the effect of chemical cues released by A. cahirinus on the time of activity of A. russatus was tested Six golden spiny mice (A. russatus), which prior to the experiments were kept separate from common spiny mice (A. cahirinus), showed nocturnal activity. They were exposed to chemical cues from the urine and faeces of conspecific and heterospecific mice of the opposite sex. The onset of activity in these mice was recorded. While the urine and faeces of conspecific mice did not have a significant effect on the time of onset of activity, heterospecific urine and faeces did cause a significant (p < 0.001) time shift and, a day after they were introduced, activity started 6.8 +/- 1.9 h earlier. This shift also took place on the second day. The results of this study suggest that the mechanism for displacement of A. russatus from nocturnal activity is by chemical signals released by A. cahirinus. Therefore, it may be concluded that chemical cues maintain time separation between these two species.

  5. Coexistence of cooperation and defection in public goods games.

    Science.gov (United States)

    Archetti, Marco; Scheuring, István

    2011-04-01

    The production of public goods by the contribution of individual volunteers is a social dilemma because an individual that does not volunteer can benefit from the public good produced by the contributions of others. Therefore it is generally believed that public goods can be produced only in the presence of repeated interactions (which allow reciprocation, reputation effects and punishment) or relatedness (kin selection). Cooperation, however, often occurs in the absence of iterations and relatedness. We show that when the production of a public good is a Volunteer's Dilemma, in which a fixed number of cooperators is necessary to produce the public good, cooperators and defectors persist in a mixed equilibrium, without iterations and without relatedness. This mixed equilibrium is absent in the N-person Prisoner's Dilemma, in which the public good is a linear function of the individual contributions. We also show that the Prisoner's Dilemma and the Volunteer's Dilemma are the two opposite extremes of a general public goods game, and that all intermediate cases can have a mixed equilibrium like the Volunteer's Dilemma. The coexistence of cooperators and defectors, therefore, is a typical outcome of most social dilemmas, which requires neither relatedness nor iterations.

  6. Evidence for shape coexistence in sup 7 sup 7 Br

    CERN Document Server

    Ray, I; Bhattacharya, S; Goswami, A; Muralithar, S; Singh, R P; Bhowmik, R K

    2001-01-01

    The nucleus sup 7 sup 7 Br has been studied in the reaction sup 6 sup 5 Cu( sup 1 sup 6 O, 2p2n) at E=75 MeV. Lifetimes have been measured for several states using the Doppler-shift attenuation technique. The B(E2) values for the inband transitions, deduced from the lifetime results, reflect strong collectivity for both the positive-parity yrast band (band 1) and the ground-state negative-parity band (band 2). States with spin above 17/2 sup + in band 1 are found to have a large average quadrupole deformation of beta sub 2 =0.35. The experimental results for band 2 suggest that the 25/2 sup - and 29/2 sup - states are somewhat more strongly deformed than the lower-spin states. A comparison of the experimental results with particle-rotor-model calculations provides evidence for shape coexistence in sup 7 sup 7 Br, favouring a prolate shape for the g sub 9 sub / sub 2 yrast band and an oblate shape for the lowest negative-parity band.

  7. Analysis of Coexistence of DRM Plus and FM Broadcasting Systems

    Directory of Open Access Journals (Sweden)

    K. Ulovec

    2015-12-01

    Full Text Available This paper deals with DRM (Digital Radio Mondiale Plus and FM (Frequency Modulation radio broadcasting systems coexistence. It brings results based on measurement of mutual interferences of each to other. Minimal necessary value of the signal to interference power ratio is measured under the given reception criteria. Results are useful for broadcasting networks planning. Different DRM Plus modes (i.e. combinations of various protection levels and data carriers modulations are assumed in the case of DRM Plus reception interfered with by FM broadcasting. The differences for various modes are crucial for coverage design of DRM Plus system, while protection ratios have been recommended for only two of eight modes until now. Corrections of protection ratios for other modes are proposed in this paper. Different waveforms types of modulating signal for interfering FM signal are tested. The both mono and stereo FM mode and various sound quality criteria are considered in the case of FM broadcasting reception interfered with by DRM Plus. The influence of peak to average power ratio reduction of interfering DRM Plus signal is observed.

  8. Sheehan's syndrome co-existing with Graves' disease.

    Science.gov (United States)

    Arpaci, D; Cuhaci, N; Saglam, F; Ersoy, R; Cakir, B

    2014-01-01

    Sheehan's syndrome (SS), which is an important cause of hypopituitarism, is common in developing countries. The most common presentation is the absence of lactation and amenorrhea. Hypothyroidism rather than hyperthyroidism is the usual expected phenomenon in SS. Postpartum hyperthyroidism is also common and Graves' disease (GD) is an important cause of postpartum hyperthyroidism. Here we report a case of a 22-year-old female patient in our clinic presented symptoms of amenorrhea, lack of lactation, palpitations and sweating. Her physical examination revealed goiter, moist skin and proptosis. Her laboratory evaluation showed suppressed thyroid stimulating hormone, elevated levels of free thyroxine and free triiodothyronine. Thyroid antibodies were positive. Tec 99m thyroid scintigraphy results were gland hyperplasia and increased uptake consistent with GD. She gave birth 7 months ago; after delivery she had a history of prolonged bleeding, amenorrhea and inability to lactate. She had hypogonadotropic hypogonadism, hyperprolactinemia and growth hormone deficiency. Serum cortisol and adrenocorticotropic hormone levels were normal. Her magnetic resonance imaging was empty sella. Our diagnosis was GD co-existing with SS. GD with concomitant hypopituitarism is rare but has been described previously, but there are no reports of GD occurring with SS. In this case study, we report a patient with GD associated with SS.

  9. Socially mediated induction and suppression of antibiosis during bacterial coexistence

    Science.gov (United States)

    Abrudan, Monica I.; Smakman, Fokko; Grimbergen, Ard Jan; Westhoff, Sanne; Miller, Eric L.; van Wezel, Gilles P.; Rozen, Daniel E.

    2015-01-01

    Despite their importance for humans, there is little consensus on the function of antibiotics in nature for the bacteria that produce them. Classical explanations suggest that bacteria use antibiotics as weapons to kill or inhibit competitors, whereas a recent alternative hypothesis states that antibiotics are signals that coordinate cooperative social interactions between coexisting bacteria. Here we distinguish these hypotheses in the prolific antibiotic-producing genus Streptomyces and provide strong evidence that antibiotics are weapons whose expression is significantly influenced by social and competitive interactions between competing strains. We show that cells induce facultative responses to cues produced by competitors by (i) increasing their own antibiotic production, thereby decreasing costs associated with constitutive synthesis of these expensive products, and (ii) by suppressing antibiotic production in competitors, thereby reducing direct threats to themselves. These results thus show that although antibiotic production is profoundly social, it is emphatically not cooperative. Using computer simulations, we next show that these facultative strategies can facilitate the maintenance of biodiversity in a community context by converting lethal interactions between neighboring colonies to neutral interactions where neither strain excludes the other. Thus, just as bacteriocins can lead to increased diversity via rock–paper–scissors dynamics, so too can antibiotics via elicitation and suppression. Our results reveal that social interactions are crucial for understanding antibiosis and bacterial community dynamics, and highlight the potential of interbacterial interactions for novel drug discovery by eliciting pathways that mediate interference competition. PMID:26216986

  10. Nuclear shapes: from earliest ideas to multiple shape coexisting structures

    Science.gov (United States)

    Heyde, K.; Wood, J. L.

    2016-08-01

    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.

  11. Bacterioplankton abundance and production and nanozooplankton abundance in Kenyan coastal waters (Western Indian Ocean)

    NARCIS (Netherlands)

    Goosen, N.K.; Van Rijswijk, P.; De Bie, M.J.M.; Peene, J.; Kromkamp, J.C.

    1997-01-01

    Bacterial abundance, [H-3]thymidine incorporation rate and heterotrophic nanoflagellate abundance were measured in the water column along transects perpendicular to the Kenyan coast (western Indian Ocean) during June-July (SE monsoon) and November-December (intermonsoon) 1992. Bacterial abundance wa

  12. Detecting Abundance Variations in Planetary Nebulae

    Science.gov (United States)

    Monteiro, H.; Santos, P. M.; Falceta-Gonçalves, D.

    2014-04-01

    Empirical methods of investigating chemical abundances are still widely used as a primary tool to study planetary nebulae (PNe) as well as HII regions. In this work we investigate the capacity of the empirical abundance determination methods to recover pre-defined parameters and abundance variations in a realistically modeled planetary nebula. To perform the test we use a threedimensional density structure obtained from a hydrodynamical simulation which is fed through a threedimensional photoionization code. The density structure is an asymetrical and inhomogeneous elongated closed shell. The input parameters used, such as, ionizing source, density, and chemical abundances are typical values of type I PNe. The model emissivities are then projected in the line of sight and emission line maps are generated, which are used to obtain the temperature and density diagnostics. The diagnostics and line emission maps are then used to obtain spatially resolved maps of the abundances. In this work we use the method described above to investigate abundances for two distinct orientations of the density structure. Our results show that for typical signal to noise ratios obtained from long-slit spectroscopy, only large abundance variations can be determined with good precision.

  13. Lithium Abundance of Metal-poor Stars

    Institute of Scientific and Technical Information of China (English)

    Hua-Wei Zhang; Gang Zhao

    2003-01-01

    High-resolution, high signal-to-noise ratio spectra have been obtained for 32 metal-poor stars. The equivalent widths of Li λ6708A were measured and the lithium abundances were derived. The average lithium abundance of 21 stars on the lithium plateau is 2.33±0.02 dex. The Lithium plateau exhibits a marginal trend along metallicity, dA(Li)/d[Fe/H] = 0.12±0.06, and no clear trend with the effective temperature. The trend indicates that the abundance of lithium plateau may not be primordial and that a part of the lithium was produced in Galactic Chemical Evolution (GCE).

  14. Study of the primordial lithium abundance

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Lithium isotopes have attracted an intense interest because the abundance of both 6Li and 6Li from big bang nucleosynthesis (BBN) is one of the puzzles in nuclear astrophysics. Many investigations of both astrophysical observation and nucleosynthesis calculation have been carried out to solve the puzzle, but it is not solved yet. Several nuclear reactions involving lithium have been indirectly measured at China Institute of Atomic Energy, Beijing. The Standard BBN (SBBN) network calculations are then performed to investigate the primordial Lithium abundance. The result shows that these nuclear reactions have minimal effect on the SBBN abundances of 6Li and 7Li.

  15. Induced spin-triplet pairing in the coexistence state of antiferromagnetism and singlet superconductivity: Collective modes and microscopic properties

    Science.gov (United States)

    Almeida, D. E.; Fernandes, R. M.; Miranda, E.

    2017-07-01

    The close interplay between superconductivity and antiferromagnetism in several quantum materials can lead to the appearance of an unusual thermodynamic state in which both orders coexist microscopically, despite their competing nature. A hallmark of this coexistence state is the emergence of a spin-triplet superconducting gap component, called a π triplet, which is spatially modulated by the antiferromagnetic wave vector, reminiscent of a pair density wave. In this paper, we investigate the impact of these π -triplet degrees of freedom on the phase diagram of a system with competing antiferromagnetic and superconducting orders. Although we focus on a microscopic two-band model that has been widely employed in studies of iron pnictides, most of our results follow from a Ginzburg-Landau analysis, and as such should be applicable to other systems of interest, such as cuprates and heavy fermion materials. The Ginzburg-Landau functional reveals not only that the π -triplet gap amplitude couples trilinearly with the singlet gap amplitude and the staggered magnetization magnitude but also that the π -triplet d -vector couples linearly with the magnetization direction. While in the mean-field level this coupling forces the d -vector to align parallel or antiparallel to the magnetization, in the fluctuation regime it promotes two additional collective modes—a Goldstone mode related to the precession of the d -vector around the magnetization and a massive mode, related to the relative angle between the two vectors, which is nearly degenerate with a Leggett-like mode associated with the phase difference between the singlet and triplet gaps. We also investigate the impact of magnetic fluctuations on the superconducting-antiferromagnetic phase diagram, showing that due to their coupling with the π -triplet order parameter the coexistence region is enhanced. This effect stems from the fact that the π -triplet degrees of freedom promote an effective attraction between

  16. 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

  17. Theoretical biology: Comparing models of species abundance - Brief Communications Arising

    NARCIS (Netherlands)

    Chave, J.; Alonso, D.; Etienne, R.S.

    2006-01-01

    Ecologists are struggling to explain how so many tropical tree species can coexist in tropical forests, and several empirical studies have demonstrated that negative density dependence is an important mechanism of tree-species coexistence1, 2. Volkov et al.3 compare a model incorporating negative de

  18. Do top-down or bottom-up forces determine Stephanitis pyrioides abundance in urban landscapes?

    Science.gov (United States)

    Shrewsbury, Paula M; Raupp, Michael J

    2006-02-01

    This study examined the influence of habitat structural complexity on the collective effects of top-down and bottom-up forces on herbivore abundance in urban landscapes. The persistence and varying complexity of urban landscapes set them apart from ephemeral agroecosystems and natural habitats where the majority of studies have been conducted. Using surveys and manipulative experiments. We explicitly tested the effect of natural enemies (enemies hypothesis), host plant quality, and herbivore movement on the abundance of the specialist insect herbivore, Stephanitis pyrioides, in landscapes of varying structural complexity. This herbivore was extremely abundant in simple landscapes and rare in complex ones. Natural enemies were the major force influencing abundance of S. pyrioides across habitat types. Generalist predators, particularly the spider Anyphaena celer, were more abundant in complex landscapes. Predator abundance was related to greater abundance of alternative prey in those landscapes. Stephanitis pyrioides survival was lower in complex habitats when exposed to endemic natural enemy populations. Laboratory feeding trials confirmed the more abundant predators consumed S. pyrioides. Host plant quality was not a strong force influencing patterns of S. pyrioides abundance. When predators were excluded, adult S. pyrioides survival was greater on azaleas grown in complex habitats, in opposition to the observed pattern of abundance. Similarly, complexity did not affect S. pyrioides immigration and emigration rates. The complexity of urban landscapes affects the strength of top-down forces on herbivorous insect populations by influencing alternative prey and generalist predator abundance. It is possible that habitats can be manipulated to promote the suppressive effects of generalist predators.

  19. The coexistence of SAPHO syndrome and rheumatoid arthritis

    Science.gov (United States)

    Xu, Wenrui; Li, Chen; Zhang, Weihong

    2017-01-01

    Abstract Rational: SAPHO (Synovitis-Acne-Pustulosis-Hyperstosis-Osteitis) syndrome is a rare disease featured by its dermatological and osteoarthritic disorders, the latter of which mainly affecting the anterior chest wall, spine, and sacroiliac joint. However, rheumatoid arthritis (RA) is a chronic autoimmune disease, mainly affecting the synovial tissue of small joints in hands and feet. Here, we present an extremely rare case diagnosed with both SAPHO syndrome and RA, with an onset interval of 10 years. So far, only 1 similar case has been reported in the English literature. Patient Concerns: In Sep 2015, a 59-year-old female patient presented to our hospital, complaining of refractory low back pain, left sternoclavicular joint pain, and palmoplanar pustulosis (PPP). In addition, RA had been diagnosed 10 years earlier in the patient, manifested as pain and swelling in bilateral hands and wrists, accompanied by morning stiffness, as well as positive serologic tests. Interventions: In our hospital, laboratory tests revealed elevated inflammatory markers, and imaging examinations of relevant sites showed specific osteoarthritic lesions for SAPHO syndrome. Diagnoses: These findings lead us to make an easy diagnosis of the coexistence of SAPHO syndrome and RA in this petient. Outcomes: Treatment with tripterygium wilfordii polyglycosidium and prednisone was introduced. Both dermatological and osteoarthritic symptoms improved during a 3-month follow-up. Symptoms of RA were successfully controlled with prednisone and leflunomide since 2005. Lessons: We present an extremely rare case diagnosed with both SAPHO syndrome and RA, with an onset interval of 10 years. With this case report, we want to draw attention to the diverse features of SAPHO syndrome. PMID:28072711

  20. Alleviation of podophyllotoxin toxicity using coexisting flavonoids from Dysosma versipellis.

    Directory of Open Access Journals (Sweden)

    Juan Li

    Full Text Available Podophyllotoxin (POD is a lignan-type toxin existing in many herbs used in folk medicine. Until now, no effective strategy is available for the management of POD intoxication. This study aims to determine the protective effects of flavonoids (quercetin and kaempferol on POD-induced toxicity. In Vero cells, both flavonoids protected POD-induced cytotoxicity by recovering alleviating G2/M arrest, decreasing ROS generation and changes of membrane potential, and recovering microtubule structure. In Swiss mice, the group given both POD and flavonoids group had significantly lower mortality rate and showed less damages in the liver and kidney than the group given POD alone. As compared to the POD group, the POD plus flavonoids group exhibited decreases in plasma transaminases, alkaline phosphatase, lactate dehydrogenase, plasma urea, creatinine and malondialdehyde levels, and increases in superoxide dismutase and glutathione levels. Histological examination of the liver and kidney showed less pathological changes in the treatment of POD plus flavonoids group. The protective mechanisms were due to the antioxidant activity of flavonoids against the oxidative stress induced by POD and the competitive binding of flavonoids against POD for the same colchicines-binding sites. The latter binding was confirmed by the tubulin assembly assay in combination with molecular docking analyses. In conclusion, this study for the first time demonstrated that the coexisting flavonoids have great protective effects against the POD toxicity, and results of this study highlighted the great potential of searching for effective antidotes against toxins based on the pharmacological clues.

  1. Shape coexistence and shell evolution in the 68Ni region

    Science.gov (United States)

    Chiara, C. J.

    2016-09-01

    Studies of nuclei along or near the line of stability have long since demonstrated the existence of certain magic numbers of protons or neutrons, corresponding to shell closures where there are large energy gaps among the single-particle orbitals. Nuclei located near these magic numbers tend to have increased stability compared to their neighbors and are typically spherical in their ground states. As technological advances continue to push our reach to nuclei farther from stability, mounting evidence has revealed that this familiar shell structure changes with increasing asymmetry in the numbers of neutrons and protons. The disappearance of some well-known magic numbers and the formation of new ones, driven largely by the tensor force, have both been identified. Along with this shell evolution as a function of nucleon number, a different type can also occur within a given nucleus as a consequence of configuration changes and the corresponding effect of their associated nuclear forces. This latter type of shell evolution manifests itself as a coexistence of spherical and deformed shapes at low excitation energies. Highlights will be presented of recent research on shell evolution in neutron-rich nuclei in the vicinity of 68Ni. Particular emphasis will be given to the efforts at Argonne National Laboratory and the National Superconducting Cyclotron Laboratory which have revealed new structure in these nuclei through multinucleon-transfer reactions and beta-decay spectroscopy. These experimental results could only be explained by concurrent advances in the corresponding shell-model description, requiring larger model spaces than could previously be accommodated. Supported by the US Army Research Lab under Cooperative Agreement W911NF-12-2-0019.

  2. Estimating Squirrel Abundance From Live trapping Data

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — A reprint of an article from the Journal of Wildlife Management entitled "Estimating Squirrel Abundance from Live Trapping Data" by Nixon, Edwards and Eberhardt. The...

  3. Chinook Abundance - Linear Features [ds181

    Data.gov (United States)

    California Department of Resources — The dataset 'ds181_Chinook_ln' is a product of the CalFish Adult Salmonid Abundance Database. Data in this shapefile are collected from stream sections or reaches...

  4. Iron abundance in the atmosphere of Arcturus

    CERN Document Server

    Sheminova, V A

    2015-01-01

    Abundance of iron in the atmosphere of Arcturus has been determined from the profiles or regions of the profiles of the weak lines sensitive to iron abundance. The selected lines of Fe I and Fe II were synthesized with the MARCS theoretical models of the atmosphere. From the observed profiles of lines available with a high spectral resolution in the atlas by Hinkle and Wallace (2005), the values of the iron abundance $A = 6.95 \\pm 0.03$ and the radial-tangential macroturbulent velocity $5.6 \\pm 0.2$ km/s were obtained for Arcturus. The same physical quantities were found for the Sun as a star; they are $7.42 \\pm 0.02$ and $3.4 \\pm 0.3$ km/s, respectively. For Arcturus, the iron abundance relative to the solar one was determined with the differential method as [Fe/H] $=-0.48 \\pm 0.02$.

  5. Chemical abundance analysis of 19 barium stars

    CERN Document Server

    Yang, G C; Spite, M; Chen, Y Q; Zhao, G; Zhang, B; Liu, G Q; Liu, Y J; Liu, N; Deng, L C; Spite, F; Hill, V; Zhang, C X

    2016-01-01

    We aim at deriving accurate atmospheric parameters and chemical abundances of 19 barium (Ba) stars, including both strong and mild Ba stars, based on the high signal-to-noise ratio and high resolution Echelle spectra obtained from the 2.16 m telescope at Xinglong station of National Astronomical Observatories, Chinese Academy of Sciences. The chemical abundances of the sample stars were obtained from an LTE, plane-parallel and line-blanketed atmospheric model by inputting the atmospheric parameters (effective temperatures, surface gravities, metallicity and microturbulent velocity) and equivalent widths of stellar absorption lines. These samples of Ba stars are giants indicated by atmospheric parameters, metallicities and kinematic analysis about UVW velocity. Chemical abundances of 17 elements were obtained for these Ba stars. Their light elements (O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn and Ni) are similar to the solar abundances. Our samples of Ba stars show obvious overabundances of neutron-capture (n-ca...

  6. SWFSC/MMTD: Vaquita Abundance Survey 1997

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In 1997, the Southwest Fisheries Science Center (SWFSC) conducted a survey designed to estimate the abundance of vaquita, the Gulf of California harbor porpoise...

  7. New constraints on the deep oxygen abundance in Uranus and Neptune

    Science.gov (United States)

    Cavalié, Thibault; Venot, Olivia; Selsis, Franck; Hersant, Franck; Hartogh, Paul

    2016-10-01

    One of the great mysteries in the Solar System is how Giant Planets formed. Two main formation scenarios coexist: disk gravitational instability and core accretion. These scenarios differ not only in the time required to form planets, but also in the final composition of the planets' interiors. In this sense, heavy element abundances are key constraints and they depend on how the ices of the planetesimal that formed the cores of these planets condensed (e.g., amorphous or crystalline).Measuring the deep oxygen abundance can help differentiating the condensation processes of the planetesimal ices. Indeed, clathration needs a larger amount of water than the amorphous ice scenario. While Galileo probably failed to measure the Jovian deep oxygen abundance, Juno should shed light on this long lasting question. Measuring Saturn's deep oxygen is a goal of the entry probe that will be proposed to ESA (Mousis et al. 2016). Regarding the Ice Giants, there is no such mission planned in the near future to measure their deep oxygen abundance and it is very challenging to probe remotely below the water cloud in these planets with microwaves. Another way to constrain the deep oxygen abundance consists in using thermochemical modeling to link upper tropospheric disequilibrium species to the deep oxygen.In this paper, we apply a thermochemical and diffusion model to the ice giant tropospheres to constrain their deep oxygen abundance from CO observations. Because the results depend on the thermal structure, on the strength of tropospheric mixing, and to a lesser extent on the deep carbon abundance, we have explored a 4D parameter space (temperature, tropospheric mixing, deep oxygen and carbon abundance) for each planet to fit their upper tropospheric composition. For instance, we have computed a series of classical thermal profiles based on dry/wet adiabats and new profiles that account for the mean molecular weight gradient at the water condensation layer (following the

  8. 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.

  9. 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.

  10. Measurements of the Coexistence Curve near the Liquid-Gas Critical Point

    Science.gov (United States)

    Hahn, Inseob

    2003-01-01

    The shape of the liquid-gas coexistence curve of He-3 very near the critical point (-2x10(exp -6) critical point was strongly affected by the gravitational field. Away from the critical point, the coexistence curve obtained using this technique was also consistent with the earlier work using the local density measurements of Pittman et al. The recent crossover parametric model of the equation-of-state are used to analyze the height-dependent measured coexistence curves. Data analyses have indicated that microgravity will permit measurements within two additional decades in reduced temperatures beyond the best gravity-free data obtained in Earth-bound experiments.

  11. Coexisting Oscillation and Extreme Multistability for a Memcapacitor-Based Circuit

    Directory of Open Access Journals (Sweden)

    Guangyi Wang

    2017-01-01

    Full Text Available The coexisting oscillations are observed with a memcapacitor-based circuit that consists of two linear inductors, two linear resistors, and an active nonlinear charge-controlled memcapacitor. We analyze the dynamics of this circuit and find that it owns an infinite number of equilibrium points and coexisting attractors, which means extreme multistability arises. Furthermore, we also show the stability of the infinite many equilibria and analyze the coexistence of fix point, limit cycle, and chaotic attractor in detail. Finally, an experimental result of the proposed oscillator via an analog electronic circuit is given.

  12. Temperature-driven volume transition in hydrogels: Phase-coexistence and interface localization

    Science.gov (United States)

    Cirillo, E. N. M.; Nardinocchi, P.; Sciarra, G.

    2016-05-01

    We study volume transition phenomenon in hydrogels within the framework of Flory-Rehner thermodynamic modelling; we show that starting from different models for the Flory parameter different conclusions can be achieved, in terms of admissible coexisting equilibria of the system. In particular, with explicit reference to a one-dimensional problem we establish the ranges of both temperature and traction which allow for the coexistence of a swollen and a shrunk phase. Through consideration of an augmented Flory-Rehner free-energy, which also accounts for the gradient of volume changes, we determine the position of the interface between the coexisting phases, and capture the connection profile between them.

  13. Does land abundance explain African institutions?

    OpenAIRE

    2012-01-01

    The land abundance view of African history uses sparse population to explain pre-colonial land tenure and slavery. I document the geographic forcing variables that predict land rights, slavery, and population density in a cross section of global societies. I discuss whether these correlations support theories of land rights and slavery, including the land abundance view. I show that pre-colonial institutions predict institutional outcomes in Africa in the present, including land transactions,...

  14. Coronae of Stars with Supersolar Elemental Abundances

    Science.gov (United States)

    Peretz, Uria; Behar, Ehud; Drake, Stephen A.

    2015-01-01

    Coronal elemental abundances are known to deviate from the photospheric values of their parent star, with the degree of deviation depending on the first ionization potential (FIP). This study focuses on the coronal composition of stars with supersolar photospheric abundances. We present the coronal abundances of six such stars: 11 LMi, iota Hor, HR 7291, tau Boo, and alpha Cen A and B. These stars all have high-statistics X-ray spectra, three of which are presented for the first time. The abundances we measured were obtained using the line-resolved spectra of the Reflection Grating Spectrometer (RGS) in conjunction with the higher throughput EPIC-pn camera spectra onboard the XMM-Newton observatory. A collisionally ionized plasma model with two or three temperature components is found to represent the spectra well. All elements are found to be consistently depleted in the coronae compared to their respective photospheres. For 11 LMi and tau Boo no FIP effect is present, while iota Hor, HR 7291, and alpha Cen A and B show a clear FIP trend. These conclusions hold whether the comparison is made with solar abundances or the individual stellar abundances. Unlike the solar corona, where low-FIP elements are enriched, in these stars the FIP effect is consistently due to a depletion of high-FIP elements with respect to actual photospheric abundances. A comparison with solar (instead of stellar) abundances yields the same fractionation trend as on the Sun. In both cases, a similar FIP bias is inferred, but different fractionation mechanisms need to be invoked.

  15. Temporal mortality-colonization dynamic can influence the coexistence and persistence patterns of cooperators and defectors in an evolutionary game model

    Directory of Open Access Journals (Sweden)

    YouHua Chen

    2014-03-01

    Full Text Available In the present report, the coexistence and persistence time patterns of Prisoners' Dilemma game players were explored in 2D spatial grid systems by considering the impacts of the mortality-colonization temporal dynamic specifically. Our results showed that the waiting time for triggering a colonization event could remarkably influence and change the extinction patterns of both cooperators and defectors. Interestingly, a relatively high frequency of stochastic colonization events could promote the persistence of defectors but not cooperators. In contrast, a low frequency of stochastic- or constant-time colonization events could facilitate the persistence of cooperators but not defectors. However, a long waiting time would be detrimental to the survival of both game players and drives them to go extinction in faster rates. At last, it was found that colonization strength played a relatively weak role on influencing the coexistence scenarios of both game players, but should be kept small if the coexistence of game players is needed to maintain. In conclusion, our study provides evidence showing that the temporal trade-off of mortality and colonization activities would influence the evolution of PD game and the persistence of cooperators and defectors.

  16. Modelling Void Abundance in Modified Gravity

    CERN Document Server

    Voivodic, Rodrigo; Llinares, Claudio; Mota, David F

    2016-01-01

    We use a spherical model and an extended excursion set formalism with drifting diffusive barriers to predict the abundance of cosmic voids in the context of general relativity as well as f(R) and symmetron models of modified gravity. We detect spherical voids from a suite of N-body simulations of these gravity theories and compare the measured void abundance to theory predictions. We find that our model correctly describes the abundance of both dark matter and galaxy voids, providing a better fit than previous proposals in the literature based on static barriers. We use the simulation abundance results to fit for the abundance model free parameters as a function of modified gravity parameters, and show that counts of dark matter voids can provide interesting constraints on modified gravity. For galaxy voids, more closely related to optical observations, we find that constraining modified gravity from void abundance alone may be significantly more challenging. In the context of current and upcoming galaxy surv...

  17. Planetary nebulae abundances and stellar evolution

    CERN Document Server

    Pottasch, S R

    2006-01-01

    A summary is given of planetary nebulae abundances from ISO measurements. It is shown that these nebulae show abundance gradients (with galactocentric distance), which in the case of neon, argon, sulfur and oxygen (with four exceptions) are the same as HII regions and early type star abundance gradients. The abundance of these elements predicted from these gradients at the distance of the Sun from the center are exactly the solar abundance. Sulfur is the exception to this; the reason for this is discussed. The higher solar neon abundance is confirmed; this is discussed in terms of the results of helioseismology. Evidence is presented for oxygen destruction via ON cycling having occurred in the progenitors of four planetary nebulae with bilobal structure. These progenitor stars had a high mass, probably greater than 5 solar masses. This is deduced from the high values of He/H and N/H found in these nebulae. Formation of nitrogen, helium and carbon are discussed. The high mass progenitors which showed oxygen de...

  18. TEA: A Code Calculating Thermochemical Equilibrium Abundances

    Science.gov (United States)

    Blecic, Jasmina; Harrington, Joseph; Bowman, M. Oliver

    2016-07-01

    We present an open-source Thermochemical Equilibrium Abundances (TEA) code that calculates the abundances of gaseous molecular species. The code is based on the methodology of White et al. and Eriksson. It applies Gibbs free-energy minimization using an iterative, Lagrangian optimization scheme. Given elemental abundances, TEA calculates molecular abundances for a particular temperature and pressure or a list of temperature-pressure pairs. We tested the code against the method of Burrows & Sharp, the free thermochemical equilibrium code Chemical Equilibrium with Applications (CEA), and the example given by Burrows & Sharp. Using their thermodynamic data, TEA reproduces their final abundances, but with higher precision. We also applied the TEA abundance calculations to models of several hot-Jupiter exoplanets, producing expected results. TEA is written in Python in a modular format. There is a start guide, a user manual, and a code document in addition to this theory paper. TEA is available under a reproducible-research, open-source license via https://github.com/dzesmin/TEA.

  19. Promoting Models

    Science.gov (United States)

    Li, Qin; Zhao, Yongxin; Wu, Xiaofeng; Liu, Si

    There can be multitudinous models specifying aspects of the same system. Each model has a bias towards one aspect. These models often override in specific aspects though they have different expressions. A specification written in one model can be refined by introducing additional information from other models. The paper proposes a concept of promoting models which is a methodology to obtain refinements with support from cooperating models. It refines a primary model by integrating the information from a secondary model. The promotion principle is not merely an academic point, but also a reliable and robust engineering technique which can be used to develop software and hardware systems. It can also check the consistency between two specifications from different models. A case of modeling a simple online shopping system with the cooperation of the guarded design model and CSP model illustrates the practicability of the promotion principle.

  20. Distribution, abundance, diversity and habitat associations of fishes across a bioregion experiencing rapid coastal development

    Science.gov (United States)

    McLean, Dianne L.; Langlois, Tim J.; Newman, Stephen J.; Holmes, Thomas H.; Birt, Matthew J.; Bornt, Katrina R.; Bond, Todd; Collins, Danielle L.; Evans, Scott N.; Travers, Michael J.; Wakefield, Corey B.; Babcock, Russ C.; Fisher, Rebecca

    2016-09-01

    Knowledge of the factors that influence spatial patterns in fish abundance, distribution and diversity are essential for informing fisheries and conservation management. The present study was conducted in the nearshore Pilbara bioregion of north-western Australia where the dynamic marine environment is characterised by large embayments, numerous islands and islets, coexisting with globally significant petrochemical and mineral industries. Within Western Australia, this nearshore bioregion has high biodiversity and is considered to play an essential role in the recruitment of species of commercial importance. To better inform future investigations into both ecological processes and planning scenarios for management, a rapid assessment of the distribution, abundance and associations with nearshore habitats of fishes across the region was conducted. Baited remote underwater stereo-video systems (stereo-BRUVs) were used to simultaneously sample the fish assemblage and habitat composition. Generalised additive mixed models (GAMMs) were used to determine whether the abundance of fishes were related to habitat and a range of environmental variables (visibility, depth, distance to 30 m and 200 m depth isobars, boat ramps and the nearest large embayment (Exmouth Gulf). A diverse fish assemblage comprising 343 species from 58 families was recorded. The abundance and distribution patterns of fishery-target species and of the five most common and abundant species and families were linked positively with areas of high relief, hard coral cover, reef and macroalgae and negatively with the distance to the nearest oceanic waters (200 m depth isobar). This study provides information that can contribute to future marine spatial planning scenarios for management of the Pilbara using a unique, analytical approach that has broad application in biogeography.

  1. Spatial and ecological overlap between coexisting sexual and parthenogenetic Schmidtea polychroa (Tricladida; Platyhelminthes)

    NARCIS (Netherlands)

    Weinzierl, Rolf P.; Beukeboom, Leo W.; Gerace, Letizia; Michiels, Nicolaas K.

    1999-01-01

    Theoretical models on the costs and benefits of sexual reproduction usually assume that sexual and parthenogenetic individuals coexist and are identical, except for their mode of reproduction. Empirical studies, however, show that conspecific sexuals and parthenogens can differ in ecological

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

    Directory of Open Access Journals (Sweden)

    Martha A. Grover

    2013-07-01

    Full Text Available 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.

  3. 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.

  4. 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...

  5. Effect of Inter Packet Delay in performance analysis of coexistence heterogeneous Wireless Packet Networks

    CERN Document Server

    Tamilselvan, G M

    2010-01-01

    As the explosive growth of the ISM band usage continues, there are many scenarios where different systems operate in the same place at the same time. One of growing concerns is the coexistence of heterogeneous wireless network systems. For the successful deployment of mission-critical systems such as wireless sensor networks, it is required to provide a solution for the coexistence. In this paper, we propose a new scheme using inter packet delay for the coexistence of IEEE 802.15.4 LRWPAN and IEEE 802.11b WLAN. To evaluate the effectiveness of the proposed scheme, measurement and simulation study are conducted using Qualnet 4.5 simulation software. The simulation results show that the proposed scheme is effective in performance improvement for coexistence network of IEEE 802.15.4 for various topologies.

  6. Shape coexistence from lifetime and branching-ratio measurements in 68,70Ni

    Science.gov (United States)

    Crider, B. P.; Prokop, C. J.; Liddick, S. N.; Al-Shudifat, M.; Ayangeakaa, A. D.; Carpenter, M. P.; Carroll, J. J.; Chen, J.; Chiara, C. J.; David, H. M.; Dombos, A. C.; Go, S.; Grzywacz, R.; Harker, J.; Janssens, R. V. F.; Larson, N.; Lauritsen, T.; Lewis, R.; Quinn, S. J.; Recchia, F.; Spyrou, A.; Suchyta, S.; Walters, W. B.; Zhu, S.

    2016-12-01

    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.

  7. 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.

  8. [A rare case of coexistence of pancreatic cystadenoma and adenocarcinoma of the rectum].

    Science.gov (United States)

    Ostapiuk, H; Kemona, A; Sulkowski, S; Sobaniec-Lotowska, M; Ostapiuk, W

    1989-05-01

    A rare coexistence is reported of a benign pancreatic tumour--cystadenoma--with anal adenocarcinoma. A particular attention is called to the histological structure of the tumour and differential diagnosis. Photographic documentation is enclosed.

  9. Competition for nutrient and light: stable coexistence, alternative stable states, or competitive exclusion?

    NARCIS (Netherlands)

    Passarge, J.; Hol, S.; Escher, M.; Huisman, J.

    2006-01-01

    Competition theory has put forward three contrasting hypotheses: Competition for nutrients and light may lead to (i) stable coexistence of species, (ii) alternative stable states, or (iii) competitive exclusion. This paper presents a detailed investigation of competition among phytoplankton species

  10. Competition for nutrients and light: Stable coexistence, alternative stable states or competitive exclusion?

    NARCIS (Netherlands)

    Passarge, J.; Hol, S.; Escher, M.; Huisman, J.

    2006-01-01

    Abstract. Competition theory has put forward three contrasting hypotheses: Competition for nutrients and light may lead to (i) stable coexistence of species, (ii) alternative stable states, or (iii) competitive exclusion. This paper presents a detailed investigation of competition among phytoplankto

  11. 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.

  12. Shape coexistence in neutron-rich Sr isotopes : Coulomb excitation of 98Sr

    NARCIS (Netherlands)

    Clément, E; Görgen, A.; Korten, W.; Walle J. van de, [No Value

    2010-01-01

    In this addendum we ask for beam time to perform Coulomb excitation of 98Sr in order to complete our program on the study of shape coexistence and evolution of collectivity in neutron rich strontium isotopes at N=60.

  13. Carotid artery stenting in patients with coexistent carotid and coronary artery disease

    Institute of Scientific and Technical Information of China (English)

    LUO Jian-fang; HUANG Wen-hui; WANG Shuo; DAI Cheng-bo; LI Guang; CHEN Ji-yan; ZHOU Ying-ling; WANG Li-juan

    2007-01-01

    @@ Atherosclerotic disease, as a systemic process, affects all arteries to varying degrees. In particular,coexistent carotid and coronary artery diseases are common; Management of such patients has been a point of continuing controversy.

  14. COEXISTENCE OF OSTEOARTHRITIS AND OSTEOPOROSIS INFEMORAL HEAD: A SCANNING ELECTRONMICROSCOPIC STUDY

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Objective To ascertain the coexistence of osteoarthritis and osteoporosis in the femoral head . Methods During total hip replacement for osteoarthritis of hip joint in 12 female patients with an average age of 56 years, the femoral heads were procured. After processing the femoral head, specimens were studied under scanning electron microscope. Results Different degrees of osteoarthritic lesions (characterized by degeneration of articular cartilage and hyperplasia of subchondral bone tissues) could coexist with osteoporotic lesions (characterized by icicle-like trabeculae ) in the femoral head. The hyperplas tic bone tissues of osteoarthritis lay in the vicinity of icicle-like trabeculae. However, they did not come into contact, nor did they exert influence on each other. Coexistence of these two different lesions covered a broad territory extending from the deep surface of subchondral bone plate to the head-neck junction of femoral head. Conclusion The results suggest that os teoarthritis and osteoporosis do coexist in the femoral head.

  15. Long-term trends in midwestern milkweed abundances and their relevance to monarch butterfly declines

    Science.gov (United States)

    Zaya, David N.; Pearse, Ian; Spyreas, Gregory

    2017-01-01

    Declines in monarch butterfly populations have prompted investigation into the sensitivity of their milkweed host plants to land-use change. Documented declines in milkweed abundance in croplands have spurred efforts to promote milkweeds in other habitats. Nevertheless, our current understanding of milkweed populations is poor. We used a long-term plant survey from Illinois to evaluate whether trends in milkweed abundance have caused monarch decline and to highlight the habitat-management practices that promote milkweeds. Milkweed abundance in natural areas has not declined precipitously, although when croplands are considered, changes in agricultural weed management have led to a 68% loss of milkweed available for monarchs across the region. Midsuccessional plant communities with few invasive species provide optimal milkweed habitat. The augmentation of natural areas and the management of existing grasslands, such as less frequent mowing and woody- and exotic-species control, may replace some of the milkweed that has been lost from croplands.

  16. Discontinuous bifurcation and coexistence of attractors in a piecewise linear map with a gap

    Institute of Scientific and Technical Information of China (English)

    Qu Shi-Xian; Lu Yong-Zhi; Zhang Lin; He Da-Ren

    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-ll, 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.

  17. Love in Transitional Victorian Age:Conflicts and coexistence in The French Lieutenant's Woman

    Institute of Scientific and Technical Information of China (English)

    XU Fei-ran

    2015-01-01

    Love is a notable and significant aspect that shows the conflicts and coexistence of transitional Victorian Age.Three modes of love,namely sacrificed love,materialized love and unconstrained love,respectively represent traditional feature,present worries and future promises.These three modes of love demonstrate the conflicts and coexistence of love in transitional Victorian age and provide an insight into John Fowles’ idea of love and freedom.

  18. Distribution of Coexisting Solid and Fluid Phases Alters the Kinetics of Collapse from Phospholipid Monolayers†

    OpenAIRE

    Yan, Wenfei; Hall, Stephen B.

    2006-01-01

    To determine how coexistence of liquid-expanded (LE) and tilted-condensed (TC) phases in phospholipid monolayers affects collapse from the air/water interface, we studied binary films containing dioleoyl phosphatidylcholine–dipalmitoyl phosphatidylcholine (DPPC) mixtures between 10 and 100% DPPC. Previously published results established that this range of compositions represents the LE–TC coexistence region at the equilibrium spreading pressure of 47 mN/m. When held at 49.5 mN/m on a captive ...

  19. Tuberculosis and metastatic carcinoma coexistence in axillary lymph node: A case report

    Directory of Open Access Journals (Sweden)

    K Chandramohan

    2003-04-01

    Full Text Available Abstract Background Coexistence of cancer and tuberculosis in axillary lymph nodes is rare. Only seven cases have been reported in the literature. Case Report We report here a case of infiltrating ductal carcinoma breast metastasizing to the axillary lymph node along with tubercular granuloma in the same lymph node without primary mammary or pulmonary tuberculosis. Conclusion Primary tuberculosis coexisting with carcinoma is of rare occurrence. A possibility should always be borne in mind especially in patients from endemic areas.

  20. Love in Transitional Victorian Age:Conflicts and coexistence in The French Lieutenant’s Woman

    Institute of Scientific and Technical Information of China (English)

    XU; Fei-ran

    2015-01-01

    Love is a notable and significant aspect that shows the conflicts and coexistence of transitional Victorian Age.Three modes of love,namely sacrificed love,materialized love and unconstrained love,respectively represent traditional feature,present worries and future promises.These three modes of love demonstrate the conflicts and coexistence of love in transitional Victorian age and provide an insight into John Fowles’ idea of love and freedom.

  1. Coexistence of Incommensurate Magnetism and Superconductivity in the Two-Dimensional Hubbard Model.

    Science.gov (United States)

    Yamase, Hiroyuki; Eberlein, Andreas; Metzner, Walter

    2016-03-04

    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 Néel order coexisting with d-wave superconductivity, the calculations reveal further coexistence regions where superconductivity is accompanied by incommensurate magnetic order.

  2. Abundance, distribution and patch formation of zooplankton

    Science.gov (United States)

    Paffenhöfer, Gustav-Adolf; Sherman, Byron K.; Lee, Thomas N.

    The goal of studies described here was to determine the responses of zooplankton taxa to phytoplankton patches which develop in and near intrusions of cold, nutrient-rich Gulf Stream water. To achieve this goal we determined the horizontal and vertical distributions of abundant mesozooplankton taxa on the south-eastern continental shelf of the USA between 29°30‧ and 31°N. The study period was from June 23 to August 16, 1981. Highest concentrations of zooplankton usually occurred in and near patches of phytoplankton. Increased phytoplankton appeared to trigger the formation of patches of the calanoid copepod Temora turbinata and the cyclopoid copepods Oithona spp. and Oncaea spp. The patches of zooplankton had greater alongshore than cross-shelf dimensions. T. turbinata responded rapidly to increased concentrations of phytoplankton by reproducing and aggregating in and above intruded waters. Oithonidae which were often, but not always, abundant in phytoplankton patches eventually attained high concentrations over most of the middle and part of the inner shelf. Their concentration and that of Oncaeidae increased steadily. Oncaeidae were not abundant in recently upwelled waters, as was T. turbinata but reached high concentrations in older intrusions when the abundance of T. turbinata remained level or decreased slowly. Both cyclopoid taxa are thought to reproduce slowly (egg sacs) compared to T. turbinata. Another taxon, the doliolids, became abundant far more rapidly in intruded waters (by asexual reproduction) than did the other three taxa. Doliolids were the most opportunistic intrusion zooplankton form. They do not regularly occur in low abundance on the shelf, as do the three copepod taxa, but develop in pulses in regions where T. turbinata and Oncaea are not abundant. Of the four taxa studied the abundance of doliolids increased and decreased most rapidly, whereas Oithona and Oncaea increased slowly and did not decrease during the study period. T. turbinata

  3. Free energy landscapes and volumes of coexisting phases for a colloidal dispersion

    Science.gov (United States)

    Lang, Trinh Hoa; Wang, G. F.; Lai, S. K.

    2010-01-01

    Treating the repulsive part of a pairwise potential by the hard-sphere form and its attractive part by the effective depletion potential form, we calculate using this model potential the colloidal domains of phase separation. Differing from the usual recipe of applying the thermodynamic conditions of equal pressure and equal chemical potential where the branches of coexisting phases are the ultimate target, we employ the free energy density minimization approach [G. F. Wang and S. K. Lai, Phys. Rev. E 70, 051402 (2004)] to crosshatch the domains of equilibrium phases, which consist of the gas, liquid, and solid homogeneous phases as well as the coexistence of these phases. This numerical procedure is attractive since it yields naturally the colloidal volume of space occupied by each of the coexisting phases. In this work, we first examine the change in structures of the fluid and solid free energy density landscapes with the effective polymer concentration. We show by explicit illustration the link between the free energy density landscapes and the development of both the metastable and stable coexisting phases. Then, attention is paid to the spatial volumes predicted at the triple point. It is found here that the volumes of spaces of the three coexisting phases at the triple point vary one dimensionally, whereas for the two coexisting phases, they are uniquely determined.

  4. 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.

  5. Trade-offs and coexistence: a lottery model applied to fig wasp communities.

    Science.gov (United States)

    Duthie, A Bradley; Abbott, Karen C; Nason, John D

    2014-06-01

    Ecological communities in which organisms complete their life cycles on discrete ephemeral patches are common and often support an unusually large number of species. Explaining this diversity is challenging for communities of ecologically similar species undergoing preemptive competition, where classic coexistence mechanisms may not readily apply. We use nonpollinating fig wasps as a model community characterized by high diversity and preemptive competition to show how subadditive population growth and a trade-off between competitor fecundity and dispersal ability can lead to coexistence. Because nonpollinator species are often closely related, have similar life histories, and compete for the same discrete resources, understanding their coexistence is challenging given competitive exclusion is expected. Empirical observations suggest that nonpollinating fig wasp species may face a trade-off between egg loads and dispersal abilities. We model a lottery in which a species' competitive ability is determined by a trade-off between fecundity and dispersal ability. Variation in interpatch distance between figs generates temporal variability in the relative benefit of fecundity versus dispersal. We show that the temporal storage effect leads to coexistence for a range of biologically realistic parameter values. We further use individual-based modeling to show that when species' traits evolve, coexistence is less likely but trait divergence can result. We discuss the implications of this coexistence mechanism for ephemeral patch systems wherein competition is strongly preemptive.

  6. Microhabitat locality allows multi-species coexistence in terrestrial plant communities

    Science.gov (United States)

    Tubay, Jerrold M.; Suzuki, Keisuke; Uehara, Takashi; Kakishima, Satoshi; Ito, Hiromu; Ishida, Atsushi; Yoshida, Katsuhiko; Mori, Shigeta; Rabajante, Jomar F.; Morita, Satoru; Yokozawa, Masayuki; Yoshimura, Jin

    2015-01-01

    Most terrestrial plant communities exhibit relatively high species diversity and many competitive species are ubiquitous. Many theoretical studies have been carried out to investigate the coexistence of a few competitive species and in most cases they suggest competitive exclusion. Theoretical studies have revealed that coexistence of even three or four species can be extremely difficult. It has been suggested that the coexistence of many species has been achieved by the fine differences in suitable microhabitats for each species, attributing to niche-separation. So far there is no explicit demonstration of such a coexistence in mathematical and simulation studies. Here we built a simple lattice Lotka-Volterra model of competition by incorporating the minute differences of suitable microhabitats for many species. By applying the site variations in species-specific settlement rates of a seedling, we achieved the coexistence of more than 10 species. This result indicates that competition between many species is avoided by the spatial variations in species-specific microhabitats. Our results demonstrate that coexistence of many species becomes possible by the minute differences in microhabitats. This mechanism should be applicable to many vegetation types, such as temperate forests and grasslands. PMID:26483077

  7. Coexistence of DTT and Mobile Broadband: A Survey and Guidelines for Field Measurements

    Directory of Open Access Journals (Sweden)

    Juha Kalliovaara

    2017-01-01

    Full Text Available This article provides a survey and a general methodology for coexistence studies between digital terrestrial television (DTT and mobile broadband (MBB systems in the ultra high frequency (UHF broadcasting band. The methodology includes characterization of relevant field measurement scenarios and gives a step-by-step guideline on how to obtain reliable field measurement results to be used in conjunction with link budget analyses, laboratory measurements, and simulations. A survey of potential European coexistence scenarios and regulatory status is given to determine feasible future use scenarios for the UHF television (TV broadcasting band. The DTT reception system behavior and performance are also described as they greatly affect the amount of spectrum potentially available for MBB use and determine the relevant coexistence field measurement scenarios. Simulation methods used in determining broadcast protection criteria and in coexistence studies are briefly described to demonstrate how the information obtained from field measurements can be used to improve their accuracy. The presented field measurement guidelines can be applied to any DTT-MBB coexistence scenarios and to a wide range of spectrum sharing and cognitive radio system coexistence measurements.

  8. Abundance differences among G and K giants

    Science.gov (United States)

    Challener, Sharon Lynn Montgomery

    Effective temperatures and surface gravities were derived for 52 G and K giants using model atmosphere. Of these, 33 were called very strong-lined (or VSL) stars primarily because of their CN line strength. We find that when compared to normal stars, the VSL stars show a mean iron overabundance of 0.15 dex. Contrary to earlier suggestions, none of the heavier elements (Z greater than 10) appear selectively enhanced. Red giants are believed to undergo mixing, thereby driving the surface abundances towards those of the stellar interior. Carbon, nitrogen, and oxygen abundances are most sensitive to mixing as they are produced through nucleosynthesis at various depths beneath the star's surface. The CNO abundances (normalized to the iron abundances) of the VSLs appear on average to be normal for G and K giants. This result suggests that the strong CN absorption seen in VSLs is not the result of unusual mixing. Their general overabundance of metal appears instead to be innate, presumably reflecting the metallicity of the gaseous clouds from which they formed. This should be settled once the appropriate number of VSL dwarfs is found. The deviations from the normal population of giants are rather small, however, and certainly not of the magnitude envisioned by Spinrad and Taylor (1969). It is likely that VSLs are merely the stars lying in the tail of the normal abundance distribution.

  9. Oxygen abundance maps of CALIFA galaxies

    CERN Document Server

    Zinchenko, I A; Grebel, E K; Sanchez, S F; Vilchez, J M

    2016-01-01

    We construct maps of the oxygen abundance distribution across the disks of 88 galaxies using CALIFA data release 2 (DR2) spectra. The position of the center of a galaxy (coordinates on the plate) were also taken from the CALIFA DR2. The galaxy inclination, the position angle of the major axis, and the optical radius were determined from the analysis of the surface brightnesses in the SDSS $g$ and $r$ bands of the photometric maps of SDSS data release 9. We explore the global azimuthal abundance asymmetry in the disks of the CALIFA galaxies and the presence of a break in the radial oxygen abundance distribution. We found that there is no significant global azimuthal asymmetry for our sample of galaxies, i.e., the asymmetry is small, usually lower than 0.05 dex. The scatter in oxygen abundances around the abundance gradient has a comparable value, $\\lesssim 0.05$ dex. A significant (possibly dominant) fraction of the asymmetry can be attributed to the uncertainties in the geometrical parameters of these galaxie...

  10. The iron abundance of the Magellanic Bridge

    CERN Document Server

    Dufton, P L; Thompson, H M A; Street, R A

    2008-01-01

    High-resolution HST ultra-violet spectra for five B-type stars in the Magellanic Bridge and in the Large and Small Magellanic Clouds have been analysed to estimate their iron abundances. Those for the Clouds are lower than estimates obtained from late-type stars or the optical lines in B-type stars by approximately 0.5 dex. This may be due to systematic errors possibly arising from non-LTE effects or from errors in the atomic data as similar low Fe abundances having previously been reported from the analysis of the ultra-violet spectra of Galactic early-type stars. The iron abundance estimates for all three Bridge targets appear to be significantly lower than those found for the SMC and LMC by approximately -0.5 dex and -0.8 dex respectively and these differential results should not be affected by any systematic errors present in the absolute abundance estimates. These differential iron abundance estimates are consistent with the underabundances for C, N, O, Mg and Si of approximately -1.1 dex relative to our...

  11. The Iron abundance in Galactic Planetary Nebulae

    CERN Document Server

    Delgado-Inglada, G; Mampaso, A; Viironen, K

    2008-01-01

    We constrain the iron abundance in a sample of 33 low-ionization Galactic planetary nebulae (PNe) using [Fe III] lines and correcting for the contribution of higher ionization states with ionization correction factors (ICFs) that take into account uncertainties in the atomic data. We find very low iron abundances in all the objects, suggesting that more than 90% of their iron atoms are condensed onto dust grains. This number is based on the solar iron abundance and implies a lower limit on the dust-to-gas mass ratio, due solely to iron, of M_dust/M_gas>1.3x10^{-3} for our sample. The depletion factors of different PNe cover about two orders of magnitude, probably reflecting differences in the formation, growth, or destruction of their dust grains. However, we do not find any systematic difference between the gaseous iron abundances calculated for C-rich and O-rich PNe, suggesting similar iron depletion efficiencies in both environments. The iron abundances of our sample PNe are similar to those derived follow...

  12. Abundance of sea kraits correlates with precipitation.

    Science.gov (United States)

    Lillywhite, Harvey B; Tu, Ming-Chung

    2011-01-01

    Recent studies have shown that sea kraits (Laticauda spp.)--amphibious sea snakes--dehydrate without a source of fresh water, drink only fresh water or very dilute brackish water, and have a spatial distribution of abundance that correlates with freshwater sites in Taiwan. The spatial distribution correlates with sites where there is a source of fresh water in addition to local precipitation. Here we report six years of longitudinal data on the abundance of sea kraits related to precipitation at sites where these snakes are normally abundant in the coastal waters of Lanyu (Orchid Island), Taiwan. The number of observed sea kraits varies from year-to-year and correlates positively with previous 6-mo cumulative rainfall, which serves as an inverse index of drought. Grouped data for snake counts indicate that mean abundance in wet years is nearly 3-fold greater than in dry years, and this difference is significant. These data corroborate previous findings and suggest that freshwater dependence influences the abundance or activity of sea kraits on both spatial and temporal scales. The increasing evidence for freshwater dependence in these and other marine species have important implications for the possible impact of climate change on sea snake distributions.

  13. Abundance of sea kraits correlates with precipitation.

    Directory of Open Access Journals (Sweden)

    Harvey B Lillywhite

    Full Text Available Recent studies have shown that sea kraits (Laticauda spp.--amphibious sea snakes--dehydrate without a source of fresh water, drink only fresh water or very dilute brackish water, and have a spatial distribution of abundance that correlates with freshwater sites in Taiwan. The spatial distribution correlates with sites where there is a source of fresh water in addition to local precipitation. Here we report six years of longitudinal data on the abundance of sea kraits related to precipitation at sites where these snakes are normally abundant in the coastal waters of Lanyu (Orchid Island, Taiwan. The number of observed sea kraits varies from year-to-year and correlates positively with previous 6-mo cumulative rainfall, which serves as an inverse index of drought. Grouped data for snake counts indicate that mean abundance in wet years is nearly 3-fold greater than in dry years, and this difference is significant. These data corroborate previous findings and suggest that freshwater dependence influences the abundance or activity of sea kraits on both spatial and temporal scales. The increasing evidence for freshwater dependence in these and other marine species have important implications for the possible impact of climate change on sea snake distributions.

  14. The solar photospheric abundance of zirconium

    CERN Document Server

    Caffau, Elisabetta; Ludwig, Hans-Günter; Bonifacio, Piercarlo; Steffen, Matthias

    2010-01-01

    Zirconium (Zr), together with strontium and yttrium, is an important element in the understanding of the Galactic nucleosynthesis. In fact, the triad Sr-Y-Zr constitutes the first peak of s-process elements. Despite its general relevance not many studies of the solar abundance of Zr were conducted. We derive the zirconium abundance in the solar photosphere with the same CO5BOLD hydrodynamical model of the solar atmosphere that we previously used to investigate the abundances of C-N-O. We review the zirconium lines available in the observed solar spectra and select a sample of lines to determine the zirconium abundance, considering lines of neutral and singly ionised zirconium. We apply different line profile fitting strategies for a reliable analysis of Zr lines that are blended by lines of other elements. The abundance obtained from lines of neutral zirconium is very uncertain because these lines are commonly blended and weak in the solar spectrum. However, we believe that some lines of ionised zirconium are...

  15. 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.

  16. Quantitative Comparison of Abundance Structures of Generalized Communities: From B-Cell Receptor Repertoires to Microbiomes

    Science.gov (United States)

    Saeedghalati, Mohammadkarim; Farahpour, Farnoush; Lange, Anja; Westendorf, Astrid M.; Seifert, Marc; Küppers, Ralf

    2017-01-01

    The community, the assemblage of organisms co-existing in a given space and time, has the potential to become one of the unifying concepts of biology, especially with the advent of high-throughput sequencing experiments that reveal genetic diversity exhaustively. In this spirit we show that a tool from community ecology, the Rank Abundance Distribution (RAD), can be turned by the new MaxRank normalization method into a generic, expressive descriptor for quantitative comparison of communities in many areas of biology. To illustrate the versatility of the method, we analyze RADs from various generalized communities, i.e. assemblages of genetically diverse cells or organisms, including human B cells, gut microbiomes under antibiotic treatment and of different ages and countries of origin, and other human and environmental microbial communities. We show that normalized RADs enable novel quantitative approaches that help to understand structures and dynamics of complex generalized communities. PMID:28114391

  17. Estimating Lion Abundance using N-mixture Models for Social Species.

    Science.gov (United States)

    Belant, Jerrold L; Bled, Florent; Wilton, Clay M; Fyumagwa, Robert; Mwampeta, Stanslaus B; Beyer, Dean E

    2016-10-27

    Declining populations of large carnivores worldwide, and the complexities of managing human-carnivore conflicts, require accurate population estimates of large carnivores to promote their long-term persistence through well-informed management We used N-mixture models to estimate lion (Panthera leo) abundance from call-in and track surveys in southeastern Serengeti National Park, Tanzania. Because of potential habituation to broadcasted calls and social behavior, we developed a hierarchical observation process within the N-mixture model conditioning lion detectability on their group response to call-ins and individual detection probabilities. We estimated 270 lions (95% credible interval = 170-551) using call-ins but were unable to estimate lion abundance from track data. We found a weak negative relationship between predicted track density and predicted lion abundance from the call-in surveys. Luminosity was negatively correlated with individual detection probability during call-in surveys. Lion abundance and track density were influenced by landcover, but direction of the corresponding effects were undetermined. N-mixture models allowed us to incorporate multiple parameters (e.g., landcover, luminosity, observer effect) influencing lion abundance and probability of detection directly into abundance estimates. We suggest that N-mixture models employing a hierarchical observation process can be used to estimate abundance of other social, herding, and grouping species.

  18. Estimating the relationship between abundance and distribution

    DEFF Research Database (Denmark)

    Rindorf, Anna; Lewy, Peter

    2012-01-01

    Numerous studies investigate the relationship between abundance and distribution using indices reflecting one of the three aspects of distribution: proportion of area occupied, aggregation, and geographical range. Using simulations and analytical derivations, we examine whether these indices...... based on Euclidean distance to the centre of gravity of the spatial distribution. Only the proportion of structurally empty areas, Lloyds index, and indices of the distance to the centre of gravity of the spatial distribution are unbiased at all levels of abundance. The remaining indices generate...... relationships between abundance and distribution even in cases where no underlying relationships exists, although the problem decreases for measures derived from Lorenz curves when samples contain more than four individuals on average. To illustrate the problem, the indices are applied to juvenile North Sea cod...

  19. Chemical Fractionation and Abundances in Coronal Plasma

    CERN Document Server

    Drake, J J

    2003-01-01

    Much of modern astrophysics is grounded on the observed chemical compositions of stars and the diffuse plasma that pervades the space between stars, galaxies and clusters of galaxies. X-ray and EUV spectra of the hot plasma in the outer atmospheres of stars have demonstrated that these environments are subject to chemical fractionation in which the abundances of elements can be enhanced and depleted by an order of magnitude or more. These coronal abundance anomalies are discussed and some of the physical mechanisms that might be responsible for producing them are examined. It is argued that coronal abundances can provide important new diagnostics on physical processes at work in solar and stellar coronae. It seems likely that other hot astrophysical plasmas will be subject to similar effects.

  20. Plant kin recognition enhances abundance of symbiotic microbial partner.

    Directory of Open Access Journals (Sweden)

    Amanda L File

    Full Text Available BACKGROUND: The stability of cooperative interactions among different species can be compromised by cheating. In the plant-mycorrhizal fungi symbiosis, a single mycorrhizal network may interact with many plants, providing the opportunity for individual plants to cheat by obtaining nutrients from the fungi without donating carbon. Here we determine whether kin selection may favour plant investment in the mycorrhizal network, reducing the incentive to cheat when relatives interact with a single network. METHODOLOGY/PRINCIPAL FINDINGS: We show that mycorrhizal network size and root colonization were greater when Ambrosia artemisiifolia L. was grown with siblings compared to strangers. Soil fungal abundance was positively correlated with group leaf nitrogen, and increased root colonization was associated with a reduced number of pathogen-induced root lesions, indicating greater benefit to plants grown with siblings. CONCLUSIONS/SIGNIFICANCE: Plants can benefit their relatives through investment in mycorrhizal fungi, and kin selection in plants could promote the persistence of the mycorrhizal symbiosis.

  1. 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

  2. Massive Access Control Aided by Knowledge-Extraction for Co-Existing Periodic and Random Services over Wireless Clinical Networks.

    Science.gov (United States)

    Du, Qinghe; Zhao, Weidong; Li, Weimin; Zhang, Xuelin; Sun, Bo; Song, Houbing; Ren, Pinyi; Sun, Li; Wang, Yichen

    2016-07-01

    The prosperity of e-health is boosted by fast development of medical devices with wireless communications capability such as wearable devices, tiny sensors, monitoring equipments, etc., which are randomly distributed in clinic environments. The drastically-increasing population of such devices imposes new challenges on the limited wireless resources. To relieve this problem, key knowledge needs to be extracted from massive connection attempts dispersed in the air towards efficient access control. In this paper, a hybrid periodic-random massive access (HPRMA) scheme for wireless clinical networks employing ultra-narrow band (UNB) techniques is proposed. In particular, the proposed scheme towards accommodating a large population of devices include the following new features. On one hand, it can dynamically adjust the resource allocated for coexisting periodic and random services based on the traffic load learned from signal collision status. On the other hand, the resource allocation within periodic services is thoroughly designed to simultaneously align with the timing requests of differentiated services. Abundant simulation results are also presented to demonstrate the superiority of the proposed HPRMA scheme over baseline schemes including time-division multiple access (TDMA) and random access approach, in terms of channel utilization efficiency, packet drop ratio, etc., for the support of massive devices' services.

  3. Analysis of 26 Barium Stars I. Abundances

    CERN Document Server

    Allen, D M; Allen, Dinah M.; Barbuy, Beatriz

    2006-01-01

    We present a detailed analysis of 26 barium stars, including dwarf barium stars, providing their atmospheric parameters (Teff, log g, [Fe/H], vt) and elemental abundances. We aim at deriving gravities and luminosity classes of the sample stars, in particular to confirm the existence of dwarf barium stars. Accurate abundances of chemical elements were derived. Abundance ratios between nucleosynthetic processes, by using Eu and Ba as representatives of the r- and s-processes are presented. High-resolution spectra with the FEROS spectrograph at the ESO-1.5m Telescope, and photometric data with Fotrap at the Zeiss telescope at the LNA were obtained. The atmospheric parameters were derived in an iterative way, with temperatures obtained from colour-temperature calibrations. The abundances were derived using spectrum synthesis for Li, Na, Al, alpha-, iron peak, s- and r-elements atomic lines, and C and N molecular lines. Atmospheric parameters in the range 4300 < Teff < 6500, -1.2 < [Fe/H] < 0.0 and 1.4...

  4. Simulation of arthropod abundance from plant composition

    Directory of Open Access Journals (Sweden)

    WenJun Zhang

    2011-04-01

    Full Text Available The relationship between arthropod abundance and plant composition is extremely complex. It is very hard to develop a mechanistic model to describe the relationship. This study aimed to simulate arthropod abundance from plant composition on grassland using an artificial neural network developed by the author, and to compare simulation performances between the neural network and conventional models. The results revealed that there were complex interactions between plants and arthropods, and the arthropod abundance on grassland was significantly determined of plant families and their cover-degrees rather than plant species and their cover-degrees. Neural network exhibited a better simulation performance than multivariate regression and response surface model. Cross validation indicated that prediction performance of neural network was also superior to these models. It was concluded that neural network is an effective tool to model arthropod abundance from plant composition on grassland. A moderate dimensionality for input space may be determined to produce a reasonably trained neural network. Such procedures for dimensionality reduction as PCE, etc., were suggested being used in the data treatment in neural network modeling. A high dimensionality for input space and a few samples in the input set would result in the deficient learning of neural network. Randomization procedure for sample submission would help to eliminate the sequence correlation but may result in a worse performance in simulation and prediction. It was suggested that randomization procedure could be used to the sample submission for these situations with a lot of samples and a lower dimensionality.

  5. Zooplankton abundance of the Andaman sea

    Digital Repository Service at National Institute of Oceanography (India)

    Madhupratap, M.; Achuthankutty, C.T.; Nair, S.R.S.; Nair, V.R.

    Zooplankton biomass and abundance of major groups from the Andaman Sea in February 1979 are presented. Average zooplankton biomass is 5.6 ml/100 m3 and is generally poor compared to reported values from east and west coasts of India. Copepoda forms...

  6. Securing abundance : The politics of energy security

    NARCIS (Netherlands)

    Kester, Johannes

    2016-01-01

    Energy Security is a concept that is known in the literature for its ‘slippery’ nature and subsequent wide range of definitions. Instead of another attempt at grasping the essence of this concept, Securing Abundance reformulates the problem and moves away from a definitional problem to a theoretical

  7. In Abundance: Networked Participatory Practices as Scholarship

    Science.gov (United States)

    Stewart, Bonnie E.

    2015-01-01

    In an era of knowledge abundance, scholars have the capacity to distribute and share ideas and artifacts via digital networks, yet networked scholarship often remains unrecognized within institutional spheres of influence. Using ethnographic methods including participant observation, interviews, and document analysis, this study investigates…

  8. North Sea Elasmobranchs: distribution, abundance and biodiversity

    NARCIS (Netherlands)

    Daan, N.; Heessen, H.J.L.; Hofstede, ter R.

    2005-01-01

    Based on data from various international and national surveys, an overview is given of the fine-scale distribution (resolution of 20¿longitude * 10¿ latitude; ¿ 10*10 nm) and trends in abundance of elasmobranch species reported from the North Sea. Presence-absence maps are produced based on 4

  9. Abundances of planetary nebula NGC2392

    NARCIS (Netherlands)

    Pottasch, S. R.; Bernard-Salas, J.; Roellig, T. L.

    The spectra of the planetary nebula NGC2392 is reanalysed using spectral measurements made in the mid-infrared with the Spitzer Space Telescope. The aim is to determine the chemical composition of this object. We also make use of IUE and ground based spectra. Abundances determined from the

  10. Toward reliable estimates of abundance: comparing index methods to assess the abundance of a Mammalian predator.

    Directory of Open Access Journals (Sweden)

    Denise Güthlin

    Full Text Available Due to time and financial constraints indices are often used to obtain landscape-scale estimates of relative species abundance. Using two different field methods and comparing the results can help to detect possible bias or a non monotonic relationship between the index and the true abundance, providing more reliable results. We used data obtained from camera traps and feces counts to independently estimate relative abundance of red foxes in the Black Forest, a forested landscape in southern Germany. Applying negative binomial regression models, we identified landscape parameters that influence red fox abundance, which we then used to predict relative red fox abundance. We compared the estimated regression coefficients of the landscape parameters and the predicted abundance of the two methods. Further, we compared the costs and the precision of the two field methods. The predicted relative abundances were similar between the two methods, suggesting that the two indices were closely related to the true abundance of red foxes. For both methods, landscape diversity and edge density best described differences in the indices and had positive estimated effects on the relative fox abundance. In our study the costs of each method were of similar magnitude, but the sample size obtained from the feces counts (262 transects was larger than the camera trap sample size (88 camera locations. The precision of the camera traps was lower than the precision of the feces counts. The approach we applied can be used as a framework to compare and combine the results of two or more different field methods to estimate abundance and by this enhance the reliability of the result.

  11. Non-Salmonid Abundance - Line Features [ds186

    Data.gov (United States)

    California Department of Resources — The CalFish Abundance Database contains a comprehensive collection of anadromous fisheries abundance information. The "Other Fish" category contains data collected...

  12. Stabilization of species coexistence in spatial models through the aggregation-segregation effect generated by local dispersal and nonspecific local interactions.

    Science.gov (United States)

    Detto, Matteo; Muller-Landau, Helene C

    2016-12-01

    Spatial interactions are widely acknowledged to play a significant role in sustaining diversity in ecological communities. However, theoretical work on this topic has focused on how spatial processes affect coexistence of species that differ in their strategies, with less attention to how spatial processes matter when competitors are equivalent. Furthermore, though it is recognized that models with local dispersal and local competition may sustain higher diversities of equivalent competitors than models in which these are not both localized, there is debate as to whether this reflects merely equalizing effects or whether there is also a stabilizing component. In this study, we explore how dispersal limitation and nonspecific local competition influence the outcome of species coexistence in communities driven by stochastic drift. We demonstrate that space alone acts as a stabilizing factor in a continuous space model with local dispersal and competition, as individuals of rare species on average experience lower total neighborhood densities, causing per capita reproductive rates to decrease systematically with increasing abundance. These effects prolong time to extinction in a closed system and enhance species diversity in an open system with constant immigration. Fundamentally, these stabilizing effects are obtained when dispersal limitation interacts with local competition to generate fluctuations in population growth rates. Thus this effect can be considered a fluctuating mechanism similar to spatial or temporal storage effects, but generated purely endogenously without requiring any exogenous environmental variability or species dissimilarities.

  13. [Coexistence of acute appendicitis and dengue fever: A case report].

    Science.gov (United States)

    Osuna-Ramos, Juan Fidel; Silva-Gracia, Carlos; Maya-Vacio, Gerardo Joel; Romero-Utrilla, Alejandra; Ríos-Burgueño, Efrén Rafael; Velarde-Félix, Jesús Salvador

    2017-01-03

    Dengue is the most important human viral disease transmitted by mosquitoes. It can be asymptomatic or it can present in any of its 3clinical forms: Dengue fever, dengue haemorrhagic fever and dengue shock syndrome. However, some atypical manifestations have been reported in surgical emergencies caused by acute appendicitis in patients with dengue fever. We report the case of an 18-year-old Mexican male who presented to the emergency department of the General Hospital of Culiacan, Sinaloa, with symptoms of dengue fever, accompanied by crampy abdominal pain with positive Rovsing and Dunphy signs. Dengue infection was confirmed by a positive NS1 antigen test performed by enzyme-linked immunosorbent assay. An abdominal ultrasound revealed an appendicular process; as the abdominal pain in the right side kept increasing, an open appendectomy was performed. Abundant inflammatory liquid was observed during the surgery, and the pathology laboratory reported an oedematous appendix with fibrinopurulent plaques, which agreed with acute ulcerative appendicitis. The patient was discharged fully recovered without complications during the follow-up period. Acute abdominal pain can be caused in some cases by dengue infection. This can be confusing, which can lead to unnecessary surgical interventions, creating additional morbidities and costs for the patient. This unusual and coincident acute appendicitis with dengue highlights the importance of performing careful clinical studies for appropriate decision making, especially in dengue endemic regions during an outbreak of this disease. Copyright © 2016 Academia Mexicana de Cirugía A.C. Publicado por Masson Doyma México S.A. All rights reserved.

  14. A Mi’kmaw Perspective on Advancing Salmon Governance in Nova Scotia, Canada: Setting the Stage for Collaborative Co-Existence

    Directory of Open Access Journals (Sweden)

    Shelley K. Denny

    2016-09-01

    Full Text Available Issues related to fisheries governance are a source of debate and tension between the Indigenous Mi’kmaq people of Nova Scotia and the Canadian Department of Fisheries and Oceans (DFO in matters concerning Atlantic salmon, Salmo salar. Within the context of the existing governance regime, this analysis compares the concept of salmon conservation and management from a Mi’kmaq perspective and proposes a collaborative co-existence approach for effective salmon governance in Nova Scotia. This approach begins by using co-management as a process, Two-Eyed Seeing as the design, and treaties as the model to achieve shared objectives of maintaining and improving abundances of salmon populations, in spite of differing mechanisms for addressing the interwoven complexities of multiple realities, conservation, and cultural identity.

  15. 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.

  16. The impact of coexistent Hashimoto's thyroiditis on lymph node metastasis and prognosis in papillary thyroid microcarcinoma.

    Science.gov (United States)

    Qu, Ning; Zhang, Ling; Lin, Dao-Zhe; Ji, Qing-Hai; Zhu, Yong-Xue; Wang, Yu

    2016-06-01

    The impact of coexistent Hashimoto's thyroiditis (HT) on lymph node metastasis (LNM) and prognosis in papillary thyroid microcarcinoma (PTMC) remains controversial. We evaluated the association of coexistent HT with clinicopathologic parameters, LNM, and prognosis by retrospectively reviewing a series of consecutive patients treated for PTMC at Fudan University Cancer Center from January 2005 to December 2010. Of all 1,250 patients with complete data for analysis, 364 (29.1 %) had coexistent HT (HT group) and 886 patients (70.9 %) had no evidence of HT (control group). The HT group had higher proportion of female (87.9 vs 70.1 %) patients, higher mean level of thyroid-stimulating hormone (TSH) (2.39 vs 2.00 mIU/L), and lower incidence of extrathyroidal extension (7.4 vs 11.7 %) than those in the control group. However, the incidence of LNM and recurrence was similar between the two groups, and HT was not associated with LNM and recurrence. A series of clinicopathologic factors identified for predicting LNM and recurrence in the control group did not show any prediction in the HT group. In summary, this study suggested that coexistent HT had insignificant protective effect on LNM and prognosis in PTMC, which was inconsistent with prior studies. Further studies aiming to determine novel predictors are recommended in PTMC patients with coexistent HT.

  17. The effects of colonization, extinction and competition on co-existence in metacommunities.

    Science.gov (United States)

    Hunt, Julia J F G; Bonsall, Michael B

    2009-07-01

    1. The co-existence of competitors in heterogeneous landscapes depends on the processes of colonization, extinction and spatial scale. In this study, we explore the metapopulation dynamics of competitive interactions. 2. Rather than simply evaluating the outcome of interspecific competition in the traditional manner, we focus on both the local population dynamic effects and the regional metapopulation processes affecting species co-existence. 3. We develop a theoretical model of regional co-existence to generate a set of predictions on the patterns of colonization necessary for co-existence and the regional processes that can lead to competitive exclusion. We empirically test these predictions using metacommunity microcosms of the interaction between two bruchid beetles (Callosobruchus chinensis, Callosobruchus maculatus). 4. Using well-replicated time series of the interaction between the bruchids and statistical methods of model fitting, we show how the qualitative and quantitative pattern of interspecific competition between the bruchid beetles is shaped by the structure of the metacommunity. 5. In unlimited dispersal metacommunities, the global exclusion of the inferior competitor is shown to be influenced more by the processes associated with extinction rather than low colonization ability. In restricted dispersal metacommunities, we show how the co-existence of competitors in a spatially heterogeneous habitat (patches connected through limited dispersal) is affected by Allee effects and life-history [colonization (dispersal) - competition] trade-offs.

  18. On fluid-solid direct coexistence simulations: the pseudo-hard sphere model.

    Science.gov (United States)

    Espinosa, Jorge R; Sanz, Eduardo; Valeriani, Chantal; Vega, Carlos

    2013-10-14

    We investigate methodological issues concerning the direct coexistence method, an increasingly popular approach to evaluate the solid-fluid coexistence by means of computer simulations. The first issue is the impact of the simulation ensemble on the results. We compare the NpT ensemble (easy to use but approximate) with the NpzT ensemble (rigorous but more difficult to handle). Our work shows that both ensembles yield similar results for large systems (>5000 particles). Another issue, which is usually disregarded, is the stochastic character of a direct coexistence simulation. Here, we assess the impact of stochasticity in the determination of the coexistence point. We demonstrate that the error generated by stochasticity is much larger than that caused by the use of the NpT ensemble, and can be minimized by simply increasing the system size. To perform this study we use the pseudo hard-sphere model recently proposed by Jover et al. [J. Chem. Phys. 137, 144505 (2012)], and obtain a coexistence pressure of p∗ = 11.65(1), quite similar to that of hard spheres (only about 0.6% higher). Therefore, we conclude that this model can be reliably used to investigate the physics of hard spheres in phenomena like crystal nucleation.

  19. Hydraulic lift as a determinant of tree-grass coexistence on savannas.

    Science.gov (United States)

    Yu, Kailiang; D'Odorico, Paolo

    2015-09-01

    The coexistence of woody plants and grasses in savannas is determined by a complex set of interacting factors that determine access to resources and demographic dynamics, under the control of external drivers and vegetation feedbacks with the physical environment. Existing theories explain coexistence mainly as an effect of competitive relations and/or disturbances. However, theoretical studies on the way facilitative interactions resulting from hydraulic lift affect tree-grass coexistence and the range of environmental conditions in which savannas are stable are still lacking. We investigated the role of hydraulic lift in the stability of tree-grass coexistence in savannas. To that end, we developed a new mechanistic model that accounts for both competition for soil water in the shallow soil and fire-induced disturbance. We found that hydraulic lift favors grasses, which scavenge the water lifted by woody plants. Thus, hydraulic lift expands (at the expenses of woodlands) the range of environmental conditions in which savannas are stable. These results indicate that hydraulic lift can be an important mechanism responsible for the coexistence of woody plants and grasses in savannas. Grass facilitation by trees through the process of hydraulic lift could allow savannas to persist stably in mesic regions that would otherwise exhibit a forest cover.

  20. GM crop co-existence: a question of choice, not prejudice.

    Science.gov (United States)

    Pearsall, Daniel

    2013-01-01

    The rapid uptake of biotech crops around the world demonstrates not only strong producer and consumer demand for the technology and its products, but also that where regulatory regimes function effectively and markets are allowed to operate as normal, co-existence between genetically modified (GM) and non-GM supply chains is readily achievable. However, the polarized debate over GMOs within the European Union over the past 15 years has resulted in a highly politicized and progressively impractical approach to the issue of GM crop co-existence, which in itself has become a further barrier to the technology's development. This article argues that co-existence should not be treated as a pro- or anti-GM issue, and that the aim of co-existence measures should be to permit consumer choice and freedom to operate whatever the production method involved. It suggests that supply chain-based solutions to co-existence, rather than Government prescription, offer the most pragmatic and flexible response to the commercial realities of servicing differentiated market demands.