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Sample records for abundance promote coexistence

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

    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

  2. Tracking neighbours promotes the coexistence of large carnivores.

    López-Bao, José Vicente; Mattisson, Jenny; Persson, Jens; Aronsson, Malin; Andrén, Henrik

    2016-01-01

    The study of competition and coexistence among similar interacting species has long been considered a cornerstone in evolutionary and community ecology. However, understanding coexistence remains a challenge. Using two similar and sympatric competing large carnivores, Eurasian lynx and wolverines, we tested the hypotheses that tracking among heterospecifics and reactive responses to potential risk decreases the probability of an agonistic encounter when predators access shared food resources, thus facilitating coexistence. Lynx and wolverines actively avoided each other, with the degree of avoidance being greater for simultaneous than time-delayed predator locations. Wolverines reacted to the presence of lynx at relatively short distances (mean: 383 m). In general, lynx stayed longer, and were more stationary, around reindeer carcasses than wolverines. However, when both predators were present at the same time around a carcass, lynx shortened their visits, while wolverine behavior did not change. Our results support the idea that risk avoidance is a reactive, rather than a predictive, process. Since wolverines have adapted to coexist with lynx, exploiting lynx-killed reindeer carcasses while avoiding potential encounters, the combined presence of both predators may reduce wolverine kill rate and thus the total impact of these predators on semi-domestic reindeer in Scandinavia. Consequently, population management directed at lynx may affect wolverine populations and human-wolverine conflicts. PMID:26979573

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

    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

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

    Verma, Gunjan; Chan, Kevin; Swami, Ananthram

    2015-11-01

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

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

    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. PMID:27466448

  6. Niche-habitat mechanisms and biotic interactions explain the coexistence and abundance of congeneric sandgrouse species.

    Benítez-López, Ana; Viñuela, Javier; Suárez, Francisco; Hervás, Israel; García, Jesús T

    2014-09-01

    Ascertaining which niche processes allow coexistence between closely related species is of special interest in ecology. We quantified variations in the environmental niches and densities of two congeneric species, the pin-tailed and the black-bellied sandgrouse (Pterocles alchata and Pterocles orientalis) in allopatry and sympatry under similar abiotic, habitat and dispersal contexts to understand their coexistence. Using principal component analysis, we defined environmental gradients (niche dimensions) including abiotic, habitat and anthropogenic variables, and calculated niche breadth, position and overlap of both species in sympatry and allopatry. Additionally, sandgrouse density was modelled as a function of the niche dimensions and the density of the other species. We found evidence that each species occupies distinct environmental niches in sympatry and in allopatry. The black-bellied sandgrouse exploits a broader range of environmental conditions (wider niche breadth) while the pin-tailed sandgrouse reaches high densities where conditions seem to match its optimum. In sympatry, both species shift their niches to intermediate positions, indicating the importance of abiotic factors in setting coexistence areas. Environmental conditions determine regional densities of pin-tailed sandgrouse whereas biotic interactions explain the density of the black-bellied sandgrouse in areas with abiotic conditions similarly conducive for both species. Highly suitable areas for the pin-tailed sandgrouse fall beyond the upper thermal limit of the black-bellied sandgrouse, leading to niche segregation and low densities for the latter. Finally, local niche shift and expansion plus possible heterospecific aggregation allow the pin-tailed sandgrouse to thrive in a priori less favourable environments. This work provides insight into how different mechanisms allow species coexistence and how species densities vary in sympatry compared to allopatry as a result of environmental

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

    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

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

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

    2015-01-01

    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...

  9. Fuzzy Mating Behavior Enhances Species Coexistence and Delays Extinction in Diverse Communities

    Cannon, Charles; Lerdau, Manuel

    2013-01-01

    Current theories about mechanisms promoting species co-existence in diverse communities assume that species only interact ecologically. Species are treated as discrete evolutionary entities, even though abundant empirical evidence indicates that patterns of gene flow such as selfing and hybridization frequently occur in plant and animal groups. Here, we allow mating behavior to respond to local species composition and abundance in a data-driven meta-community model of species co-existence. Wh...

  10. 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

    G Mark Fowler

    2014-04-01

    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

  11. Variação espacial como mecanismo promotor da coexistência em comunidades de insetos necrófagos Spatial variation as a mechanism promoting coexistence in carrion insect communities

    Mauricio O. Moura

    2004-01-01

    A coexistência em comunidades locais pode ser mediada através de vários mecanismos tais como competição interespecífica e heterogeneidade espacial e temporal. Neste trabalho é analisada uma guilda de insetos necrófagos para se determinar o papel desempenhado pela agregação na estrutura da comunidade. Um experimento foi delineado para se testar as premissas derivadas do modelo de coexistência por agregação que, em resumo, requer que no balanço entre a competição intra e interespecífica, a prim...

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

    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. PMID:24561598

  13. Variação espacial como mecanismo promotor da coexistência em comunidades de insetos necrófagos Spatial variation as a mechanism promoting coexistence in carrion insect communities

    Mauricio O. Moura

    2004-09-01

    Full Text Available A coexistência em comunidades locais pode ser mediada através de vários mecanismos tais como competição interespecífica e heterogeneidade espacial e temporal. Neste trabalho é analisada uma guilda de insetos necrófagos para se determinar o papel desempenhado pela agregação na estrutura da comunidade. Um experimento foi delineado para se testar as premissas derivadas do modelo de coexistência por agregação que, em resumo, requer que no balanço entre a competição intra e interespecífica, a primeira deva ser maior, para fazer com a coexistência seja possível. Os dados coletados compreendem dois protocolos: a coleta de adultos visitando a carcaça e a criação das larvas coletadas na carcaça. Os resultados demonstram que 21 espécies necrófagas foram criadas e 18 espécies coletadas. Todas as espécies mostraram-se distribuídas de forma agregada sobre os recursos e, embora vários valores negativos foram obtidos nos índice de associação, a tendência geral foi de uma covariação neutra entre as espécies. A análise confirma que a agregação pode manter a diversidade nesta comunidade.Coexistence in local communities could be mediated through several mechanisms such as interespecific competition, temporal and spatial heterogeneity. In this paper we analyse a highly diverse guild of necrophagous insects to determine the role played by aggregation on community structure. An experiment was designed to test predictions derived from aggregation model of coexistence that in short require that in the balance between intra and interespecific competition, the first one must be greater than interespecific competition in order to make coexistence more likely. The data gathered comprise two protocols: collecting adults visiting carcasses and rearing maggots collected from carcasses. The results showed a total of 21 necrophagous species reared and 18 collected. All species showed clumped patterns of distribution over resources and even

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

    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...... and in concentrated urine samples no difference was detected between placebo and spironolactone group by ELISA while western immunoblotting showed correlation of urine prostasin with albumin and a reduction in both with spironolactone. Patients with proteinuria displayed elevated u-prostasin compared to control...

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

    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.

  16. BCL2 accelerates inflammation-induced BALB/c plasmacytomas and promotes novel tumors with coexisting T(12;15) and T(6;15) translocations.

    Silva, Santiago; Kovalchuk, Alexander L; Kim, Joong Su; Klein, George; Janz, Siegfried

    2003-12-15

    Previous studies on peritoneal plasmacytomas (PCTs) in BALB/c (C) mice suggested that the enforced expression of the death repressor BCL2 in B cells might facilitate the malignant transformation of aberrant B cells containing Myc-activating T(12;15) translocations, generating an improved model of plasmacytomagenesis. To investigate this hypothesis, we backcrossed a human BCL2 transgene onto strain C and performed a PCT induction study with pristane in the newly generated C.BCL2 congenics. In specific pathogen-free-maintained C.BCL2 mice, PCT incidence (19 of 34, 56%) was 24 times higher than in specific pathogen-free-maintained C mice (1 of 44, 2.3%), and tumor onset (113 days) was half that of conventionally maintained C mice (220 days). BCL2 transgenic PCT harbored T(12;15) translocations (12 of 12 tumors) with an unusual clustering of translocation breakpoints in the near 5' flank of Myc (4 of 5 tumors, 80%). Five tumors contained coexisting T(12;15) and T(6;15) translocations (not observed in >300 karyotyped PCTs from conventionally maintained C mice). BCL2 transgenic C57BL/6 mice exclusively developed B lymphomas (11 of 20, 55%) that also contained T(12;15) translocations (11 of 11 cases) with breakpoints in the near 5' flank of Myc (five of five tumors). We conclude that BCL2 accelerates PCT with novel Myc-activating translocations independently of environmental antigen stimulation. Accelerated plasmacytomagenesis in strain C.BCL2 may be useful for designing and testing BCL2 inhibition strategies in human plasma cell tumors overexpressing BCL2, such as Waldenström's macroglobulinemia and multiple myeloma. PMID:14695177

  17. Coexistence of competing stage-structured populations.

    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.

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

    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. PMID:25200982

  19. Competitive coexistence in stoichiometric chaos

    Deng, Bo; Loladze, Irakli

    2007-09-01

    Classical predator-prey models, such as Lotka-Volterra, track the abundance of prey, but ignore its quality. Yet, in the past decade, some new and occasionally counterintuitive effects of prey quality on food web dynamics emerged from both experiments and mathematical modeling. The underpinning of this work is the theory of ecological stoichiometry that is centered on the fact that each organism is a mixture of multiple chemical elements such as carbon (C), nitrogen (N), and phosphorus (P). The ratios of these elements can vary within and among species, providing simple ways to represent prey quality as its C:N or C:P ratios. When these ratios modeled to vary, as they frequently do in nature, seemingly paradoxical results can arise such as the extinction of a predator that has an abundant and accessible prey. Here, for the first time, we show analytically that the reduction in prey quality can give rise to chaotic oscillations. In particular, when competing predators differ in their sensitivity to prey quality then all species can coexist via chaotic fluctuations. The chaos generating mechanism is based on the existence of a junction-fold point on the nullcline surfaces of the species. Conditions on parameters are found for such a point, and the singular perturbation method and the kneading sequence analysis are used to demonstrate the existence of a period-doubling cascade to chaos as a result of the point.

  20. Promotion

    Alam, Hasan B.

    2013-01-01

    This article gives an overview of the promotion process in an academic medical center. A description of different promotional tracks, tenure and endowed chairs, and the process of submitting an application is provided. Finally, some practical advice about developing skills and attributes that can help with academic growth and promotion is dispensed.

  1. China and Coexistence

    Odgaard, Liselotte

    through a comparative study of aspiring powers in the nineteenth and twentieth centuries. She explores its role in China’s border disputes in the South China Sea and with Russia and India; in diplomacy in the UN Security Council over Iran, Sudan, and Myanmar; and in China’s handling of challenges to the......“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...

  2. Pollinator Foraging Adaptation and Coexistence of Competing Plants

    Revilla, Tomás A.; Křivan, Vlastimil

    2016-01-01

    We use the optimal foraging theory to study coexistence between two plant species and a generalist pollinator. We compare conditions for plant coexistence for non-adaptive vs. adaptive pollinators that adjust their foraging strategy to maximize fitness. When pollinators have fixed preferences, we show that plant coexistence typically requires both weak competition between plants for resources (e.g., space or nutrients) and pollinator preferences that are not too biased in favour of either plant. We also show how plant coexistence is promoted by indirect facilitation via the pollinator. When pollinators are adaptive foragers, pollinator’s diet maximizes pollinator’s fitness measured as the per capita population growth rate. Simulations show that this has two conflicting consequences for plant coexistence. On the one hand, when competition between pollinators is weak, adaptation favours pollinator specialization on the more profitable plant which increases asymmetries in plant competition and makes their coexistence less likely. On the other hand, when competition between pollinators is strong, adaptation promotes generalism, which facilitates plant coexistence. In addition, adaptive foraging allows pollinators to survive sudden loss of the preferred plant host, thus preventing further collapse of the entire community. PMID:27505254

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

    Lins de Barros, M M; Castro, C B; Pires, D O; Segal, B

    2000-12-01

    The first study on coexistence of reef benthic organisms in Brazilian coral reefs was done in three localities of the Abrolhos Archipelago. Organisms were recorded in concentric circle samples (10 and 20 cm in diameter) randomly laid on transects. Type and frequency of "coexistence events" between pairs of organisms were determined. Most frequent organisms (massive and branched coralline algae, Favia gravida, and Agaricia agaricites) also had many significant positive coexistence events. These results might be related to the abundances of these organisms. The most frequent coral (Siderastrea stellata), however, exhibited only a few significant coexistence events (9% of 32 tests). Since the great majority of events were positive, and since there was high variation in the species/groups involved in significant events in different localities, benthic communities of Abrolhos Archipelago may well be structured primarily by abiotic rather than biotic factors. PMID:11487922

  4. Coexistence between neighbours

    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...

  5. Networks with dispersed degrees save stable coexistence of species in cyclic competition

    Masuda, Naoki; Konno, Norio

    2006-12-01

    Coexistence of individuals with different species or phenotypes is often found in nature in spite of competition between them. Stable coexistence of multiple types of individuals have implications for maintenance of ecological biodiversity and emergence of altruism in society, to name a few. Various mechanisms of coexistence including spatial structure of populations, heterogeneous individuals, and heterogeneous environments, have been proposed. In reality, individuals disperse and interact on complex networks. We examine how heterogeneous degree distributions of networks influence coexistence, focusing on models of cyclically competing species. We show analytically and numerically that heterogeneity in degree distributions promotes stable coexistence.

  6. Dynamical symmetry and shape coexistence

    A general discussion is given of extending the Fermion Dynamical Symmetry Model to describe shape coexistence. The theory is applied to the description of superdeformation and normal deformations through alternative dynamical symmetries

  7. Intraspecific genetic variation and species coexistence in plant communities.

    Ehlers, Bodil K; Damgaard, Christian F; Laroche, Fabien

    2016-01-01

    Many studies report that intraspecific genetic variation in plants can affect community composition and coexistence. However, less is known about which traits are responsible and the mechanisms by which variation in these traits affect the associated community. Focusing on plant-plant interactions, we review empirical studies exemplifying how intraspecific genetic variation in functional traits impacts plant coexistence. Intraspecific variation in chemical and architectural traits promotes species coexistence, by both increasing habitat heterogeneity and altering competitive hierarchies. Decomposing species interactions into interactions between genotypes shows that genotype × genotype interactions are often intransitive. The outcome of plant-plant interactions varies with local adaptation to the environment and with dominant neighbour genotypes, and some plants can recognize the genetic identity of neighbour plants if they have a common history of coexistence. Taken together, this reveals a very dynamic nature of coexistence. We outline how more traits mediating plant-plant interactions may be identified, and how future studies could use population genetic surveys of genotype distribution in nature and methods from trait-based ecology to better quantify the impact of intraspecific genetic variation on plant coexistence. PMID:26790707

  8. Plant functional traits and the multidimensional nature of species coexistence

    Kraft, Nathan J. B.; Godoy, Oscar; Levine, Jonathan M

    2015-01-01

    Biologists have long understood that differences between species in traits such as bill shape or rooting depth can maintain diversity in communities by promoting specialization and reducing competition. Here we test the assumption that phenotypic differences drive the stabilizing niche differences that promote coexistence. Using advances in ecological theory and detailed experiments we quantify average fitness and stabilizing niche differences between 102 plant species pairs and relate these ...

  9. Two coexisting tank bromeliads host distinct algal communities on a tropical inselberg.

    Carrias, J-F; Céréghino, R; Brouard, O; Pélozuelo, L; Dejean, A; Couté, A; Corbara, B; Leroy, C

    2014-09-01

    The tank bromeliads Aechmea aquilega (Salisb.) and Catopsis berteroniana (Schultes f.) coexist on a sun-exposed Neotropical inselberg in French Guiana, where they permit conspicuous freshwater pools to form that differ in size, complexity and detritus content. We sampled the algal communities (both eukaryotic and cyanobacterial taxa, including colourless forms) inhabiting either A. aquilega (n = 31) or C. berteroniana (n = 30) and examined differences in community composition and biomass patterns in relation to several biotic and abiotic variables. Chlorella sp. and Bumilleriopsis sp. were the most common taxa and dominated the algal biomass in A. aquilega and C. berteroniana, respectively. Using a redundancy analysis, we found that water volume, habitat complexity and the density of phagotrophic protozoa and collector-gatherer invertebrates were the main factors explaining the distribution of the algal taxa among the samples. Hierarchical clustering procedures based on abundance and presence/absence data clearly segregated the samples according to bromeliad species, revealing that the algal communities in the smaller bromeliad species were not a subset of the communities found in the larger bromeliad species. We conclude that, even though two coexisting tank bromeliad populations create adjacent aquatic habitats, each population hosts a distinct algal community. Hence, bromeliad diversity is thought to promote the local diversity of freshwater algae in the Neotropics. PMID:24400863

  10. Coexistence of neuropeptides in hydra

    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...

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

    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.

  12. Shape coexistence in 153Ho

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

    2016-08-01

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

  13. Shape coexistence in 153Ho

    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.

  14. Stoichiometry is crucial for modelling phytoplankton coexistence

    Göthlich, Lena; Oschlies, Andreas

    2010-05-01

    Owing to global warming, conditions in the pelagial are expected to change significantly. Rising temperatures will trigger shoaling of mixed layer depths, leading to increased light intensity and decreased nutrient supply. Adaptations of the pelagic ecosystems may include shifts in phytoplankton community composition, such as shifting dominance towards species tolerating more light and heat and/or lower nutrient concentrations, as well as changes in the extents of biogeochemical provinces and corresponding distributions of species abundances. Modelling adaptive responses to climate change requires representing phytoplankton biodiversity in global biogeochemical models. Modelling several species over longer time scales has proven to be difficult, since one species will usually outcompete all others, especially in oligotrophic areas, where the system is almost in equilibrium, resembling a chemostat. The R* concept as part of Tilman's resource competition theory (D Tilman, Am. Nat. 1980, Vol 116(3) pp. 362-393) predicts that for any given limiting resource, only the species with the lowest requirement for that resource will survive: In equilibrium, a monoculture of any species will reduce the concentration of its limiting resource to the lowest concentration allowing for its survival (R*), such that growth rate equals losses. In a multi-species assemblage, the species requiring the lowest resource concentration to survive will set the equilibrium resource concentration to its R*, which however is too low to allow for any other species to survive. The R* concept implies that in equilibrium, there can be at maximum one species for every given limiting resource. Thus, including several potentially limiting resources and parameterising the phytoplankton species such that each species is limited by a different resource, i.e. each species has the highest requirement for one resource among all species, is a necessary condition for the existence of an equilibrium including

  15. Early mesozoic coexistence of amniotes and hepadnaviridae.

    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.

  16. Coexistence in stochastic spatial models

    Durrett, Rick

    2009-01-01

    In this paper I will review twenty years of work on the question: When is there coexistence in stochastic spatial models? The answer, announced in Durrett and Levin [Theor. Pop. Biol. 46 (1994) 363--394], and that we explain in this paper is that this can be determined by examining the mean-field ODE. There are a number of rigorous results in support of this picture, but we will state nine challenging and important open problems, most of which date from the 1990's.

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

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

    2016-03-30

    Evolutionary biologists since Darwin have hypothesized that closely related species compete more intensely and are therefore less likely to coexist. However, recent theory posits that species diverge in two ways: either through the evolution of 'stabilizing differences' that promote coexistence by causing individuals to compete more strongly with conspecifics than individuals of other species, or through the evolution of 'fitness differences' that cause species to differ in competitive ability and lead to exclusion of the weaker competitor. We tested macroevolutionary patterns of divergence by competing pairs of annual plant species that differ in their phylogenetic relationships, and in whether they have historically occurred in the same region or different regions (sympatric versus allopatric occurrence). For sympatrically occurring species pairs, stabilizing differences rapidly increased with phylogenetic distance. However, fitness differences also increased with phylogenetic distance, resulting in coexistence outcomes that were unpredictable based on phylogenetic relationships. For allopatric species, stabilizing differences showed no trend with phylogenetic distance, whereas fitness differences increased, causing coexistence to become less likely among distant relatives. Our results illustrate the role of species' historical interactions in shaping how phylogenetic relationships structure competitive dynamics, and offer an explanation for the evolution of invasion potential of non-native species. PMID:27009226

  18. Coexistence in preferential attachment networks

    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...

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

    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.

  20. Intermittent control of coexisting attractors.

    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. PMID:23690639

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

    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....

  2. Stable coexistence of ecologically identical species: conspecific aggregation via reproductive interference.

    Ruokolainen, Lasse; Hanski, Ilkka

    2016-05-01

    Stable coexistence of ecologically identical species is not possible according to the established ecological theory. Many coexistence mechanisms have been proposed, but they all involve some form of ecological differentiation among the competing species. The aggregation model of coexistence would predict coexistence of identical species if there would be a mechanism that generates spatially aggregated distributions that are not completely correlated among the species. Our aim is to demonstrate that continued dispersal, triggered by reproductive interference between ecologically identical species, is such a mechanism. This study has been motivated by species using ephemeral patchy resources, such as decomposing fruits, fungal sporophores, carrion, and dung. We analyse an individual-based model with sexual reproduction, in which the progeny develops in ephemeral resource patches and the new generation disperses to a new set of patches. We assume spatially restricted dispersal, that patches differ in detectability, and that unmated females continue dispersal. In the model, reproductive interference (males spend some time searching for and/or attempting to mate with heterospecific females) reduces the mating rate of females, especially in the less common species, which leads to increased dispersal and reduces spatial correlation in species' distributions. For a wide range of parameter values, coexisting species show a systematic difference in their relative abundances due to two opposing forces: (1) uncommon species have reduced growth rate (Allee effect), which decreases abundance; (2) an abundance difference between the species reduces interspecific spatial correlation, which in turn reduces interspecific competition and allows the rarer species to persist at low density. Our results demonstrate a new mechanism for coexistence that is not based on ecological differentiation between species. PMID:26781758

  3. Shape/phase coexistence in 156 Dy

    Recent results indicate that in 152 Sm90 a spherical excited configuration coexists with a deformed ground state configuration. Detailed knowledge of other N = 90 nuclei is important in studying the evolution of shape/phase coexistence along this isotonic chain. In the present study, low-lying states of 156 Dy90 were populated in β decay and studied through γ-ray spectroscopy, permitting improved measurement of transition strengths important in the interpretation of the structure of 156 Dy. (authors)

  4. Coexistence of myasthenia gravis and pemphigus foliaceus.

    Kim, H. T.; Kim, S. H.; Kim, J. H.; Kim, M H; Lee, C. W.

    1995-01-01

    Myasthenia gravis and pemphigus are both considered to have an autoimmune basis. Although immunological and clinical studies have been performed on large numbers of patients with myasthenia gravis, the coexistence of myasthenia gravis and pemphigus foliaceus has rarely been described. We recently have the opportunity to study a 33-year-old female patient having both of these autoimmune diseases confirmed by various diagnostic methods. This rare coexistence of myasthenia gravis and pemphigus f...

  5. Solvable model for template coexistence in protocells

    Fontanari, J. F.; Serva, M.

    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 compe...

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

    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…

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

    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.

  8. Diversity is maintained by seasonal variation in species abundance

    2013-01-01

    Background Some of the most marked temporal fluctuations in species abundances are linked to seasons. In theory, multispecies assemblages can persist if species use shared resources at different times, thereby minimizing interspecific competition. However, there is scant empirical evidence supporting these predictions and, to the best of our knowledge, seasonal variation has never been explored in the context of fluctuation-mediated coexistence. Results Using an exceptionally well-documented estuarine fish assemblage, sampled monthly for over 30 years, we show that temporal shifts in species abundances underpin species coexistence. Species fall into distinct seasonal groups, within which spatial resource use is more heterogeneous than would be expected by chance at those times when competition for food is most intense. We also detect seasonal variation in the richness and evenness of the community, again linked to shifts in resource availability. Conclusions These results reveal that spatiotemporal shifts in community composition minimize competitive interactions and help stabilize total abundance. PMID:24007204

  9. Relative species abundance of replicator dynamics with sparse interactions

    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...

  10. Can pollination niches facilitate plant coexistence?

    Pauw, Anton

    2013-01-01

    The question of why there are so many plant species needs two kinds of answer: an explanation for the origin of plant species, and an explanation for how they can coexist. Pollinators are often implicated in the origin of plant species because adaptation to different modes of pollination can drive divergence in floral traits and bring about reproductive isolation. However, very few studies have attempted to answer the next question: 'Can plant species that differ only in their mode of pollination coexist?' Fragmentary evidence supports the idea that intraspecific competition for pollination resources can limit population growth rate, thus allowing the coexistence of species that use different pollinators, or the same pollinators at different times. PMID:22951227

  11. Solvable model for template coexistence in protocells

    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.

  12. Solvable model for template coexistence in protocells

    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.

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

    Chen, Y.; Gong, S.-L.

    2015-11-01

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

  14. Print vs digital the future of coexistence

    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

  15. How variation between individuals affects species coexistence.

    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. PMID:27250037

  16. Trait-based tests of coexistence mechanisms.

    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. PMID:23910482

  17. Environmental variation, stochastic extinction, and competitive coexistence.

    Adler, Peter B; Drake, John M

    2008-11-01

    Understanding how environmental fluctuations affect population persistence is essential for predicting the ecological impacts of expected future increases in climate variability. However, two bodies of theory make opposite predictions about the effect of environmental variation on persistence. Single-species theory, common in conservation biology and population viability analyses, suggests that environmental variation increases the risk of stochastic extinction. By contrast, coexistence theory has shown that environmental variation can buffer inferior competitors against competitive exclusion through a storage effect. We reconcile these two perspectives by showing that in the presence of demographic stochasticity, environmental variation can increase the chance of extinction while simultaneously stabilizing coexistence. Our stochastic simulations of a two-species storage effect model reveal a unimodal relationship between environmental variation and coexistence time, implying maximum coexistence at intermediate levels of environmental variation. The unimodal pattern reflects the fact that the stabilizing influence of the storage effect accumulates rapidly at low levels of environmental variation, whereas the risk of extinction due to the combined effects of environmental variation and demographic stochasticity increases most rapidly at higher levels of variation. Future increases in environmental variation could either increase or decrease an inferior competitor's expected persistence time, depending on the distance between the present level of environmental variation and the optimal level anticipated by this theory. PMID:18817458

  18. Feedback mechanisms control coexistence in a stem cell model of acute myeloid leukaemia.

    Crowell, Helena L; MacLean, Adam L; Stumpf, Michael P H

    2016-07-21

    Haematopoietic stem cell dynamics regulate healthy blood cell production and are disrupted during leukaemia. Competition models of cellular species help to elucidate stem cell dynamics in the bone marrow microenvironment (or niche), and to determine how these dynamics impact leukaemia progression. Here we develop two models that target acute myeloid leukaemia with particular focus on the mechanisms that control proliferation via feedback signalling. It is within regions of parameter space permissive of coexistence that the effects of competition are most subtle and the clinical outcome least certain. Steady state and linear stability analyses identify parameter regions that allow for coexistence to occur, and allow us to characterise behaviour near critical points. Where analytical expressions are no longer informative, we proceed statistically and sample parameter space over a coexistence region. We find that the rates of proliferation and differentiation of healthy progenitors exert key control over coexistence. We also show that inclusion of a regulatory feedback onto progenitor cells promotes healthy haematopoiesis at the expense of leukaemia, and that - somewhat paradoxically - within the coexistence region feedback increases the sensitivity of the system to dominance by one lineage over another. PMID:27130539

  19. Climate variability has a stabilizing effect on the coexistence of prairie grasses.

    Adler, Peter B; HilleRisLambers, Janneke; Kyriakidis, Phaedon C; Guan, Qingfeng; Levine, Jonathan M

    2006-08-22

    How expected increases in climate variability will affect species diversity depends on the role of such variability in regulating the coexistence of competing species. Despite theory linking temporal environmental fluctuations with the maintenance of diversity, the importance of climate variability for stabilizing coexistence remains unknown because of a lack of appropriate long-term observations. Here, we analyze three decades of demographic data from a Kansas prairie to demonstrate that interannual climate variability promotes the coexistence of three common grass species. Specifically, we show that (i) the dynamics of the three species satisfy all requirements of "storage effect" theory based on recruitment variability with overlapping generations, (ii) climate variables are correlated with interannual variation in species performance, and (iii) temporal variability increases low-density growth rates, buffering these species against competitive exclusion. Given that environmental fluctuations are ubiquitous in natural systems, our results suggest that coexistence based on the storage effect may be underappreciated and could provide an important alternative to recent neutral theories of diversity. Field evidence for positive effects of variability on coexistence also emphasizes the need to consider changes in both climate means and variances when forecasting the effects of global change on species diversity. PMID:16908862

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

    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.

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

    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...

  2. Nuclear power generation and co-existence with local area

    In addition to originally strong anxiety and unreliability on nuclear power generation, frequent accidents and troubles in the old Nuclear Reactor and Fuels Development Incorporation (the new Nuclear Fuel Cycle Development Incorporation), a fact that numbers of opposition group was over a half at citizen's vote conducted first in Japan and at Maki-machi in Niigata prefecture in August, 1996 on location of a nuclear power generation of the Tohoku Electric Co., Ltd., and so forth, affects some ripple effects to make difficult to form consensus on new location of a nuclear power generation. On making consensus of such location, every electric companies practise good communication with location areas, communication and other organizations, and so forth, promote positive information supplies and conversation type understanding works, and effort to acquire reliability for people of the location areas. Together with such efforts, they accumulate steadily safe operation results of the present nuclear power plants and develop nuclear PA (public acceptance) actions, local area promotion supporting countermeasures, and so forth. Here was introduced on a part of actions aiming at assistance to and co-existence with local areas promoted by every electric companies on various forms. (G.K.)

  3. The coexistence of species La coexistencia de especies

    CALEB E. GORDON

    2000-01-01

    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...

  4. Coexisting principles and logics of elder care

    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...... professional care worker and that it coexists with consumer-oriented service and without major tensions in the logics identified in their practices....

  5. Coexistence of periods in a bifurcation

    Highlights: ► The bifurcation of the Varley–Gradwell–Hassell population model is revisited. ► The structure of the attractor mediating the bifurcation to chaos is studied. ► Geometric arguments are given for the coexistence of periods in the attractor. ► An algebraic method for the localization of these bifurcations is provided. - Abstract: A particular type of order-to-chaos transition mediated by an infinite set of coexisting neutrally stable limit cycles of different periods is studied in the Varley–Gradwell–Hassell population model. We prove by an algebraic method that this kind of transition can only happen for a particular bifurcation parameter value. Previous results on the structure of the attractor at the transition point are here simplified and extended.

  6. Coexistence and sport: the Israeli case

    Yair Galily

    2013-12-01

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

  7. Co-existence of agricultural production systems.

    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. PMID:16545877

  8. Coexisting principles and logics of elder care

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

    2015-01-01

    -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 of the...... professional care worker and that it coexists with consumer-oriented service and without major tensions in the logics identified in their practices....

  9. Coexistence of competing stage-structured populations

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

    2011-01-01

    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 limit...

  10. PLURALISTIC WORLDVIEW OF BUDDHISM TOWARDS COEXISTENCE

    M. George JOSEPH

    2015-01-01

    This paper tries to conceive a pluralistic, non-centric, auto-regulated, dialectical and dynamic world view that can accommodate diversity or difference and establish a ground for mutual recognition and coexistence. Universe is a common name for the plurality of auto constructing and destructing continuity of existences in dependence. There is neither uniform purpose nor unity among them. Auto constructing and destructing activities of individual units towards the attainment of their ends are...

  11. Competitive coexistence of two Pneumocystis species.

    Icenhour, Crystal R; Arnold, Jonathan; Medvedovic, Mario; Cushion, Melanie T

    2006-05-01

    Pneumocystis are fungal pathogens of mammalian lungs that can cause lethal pneumonia in immunocompromised hosts. In some mammals, coinfections of genetically distinct Pneumocystis populations have been identified, but the nature of their interaction and its significance are unknown. Two species that infect rats, Pneumocystis carinii and Pneumocystis wakefieldiae, were studied over a 6-year period, representing approximately 700 generations of Pneumocystis. Population densities of each species were analyzed within the framework of the Lotka-Volterra competition model, which revealed the two species were in competition and predicted competitive exclusion of one species. However, stable coexistence was observed in 460 replicate populations. Selected extrinsic factors that might mitigate the extinction were evaluated. Logistic-regression analyses showed that higher relative humidity and higher organism lung burdens were associated with infections comprised of P. carinii alone, while lower temperatures and an increased rat census were associated with the presence of P. wakefieldiae. PCR and immunofluorescent analysis of rat lung tissue showed that both species were present within the same alveoli, excluding habitat heterogeneity as a mechanism of coexistence. These data suggest that P. carinii and P. wakefieldiae were in competitive coexistence, which was influenced in part by extrinsic factors. To our knowledge, this is the first report to evaluate interactions of pathogenic fungal species within a mammalian host using ecological models. PMID:15949973

  12. Tuberous sclerosis complex coexistent with hippocampal sclerosis.

    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. PMID:26498091

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

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

    2015-01-01

    Plant community patterns in space and time may be explained by the interactions between competing plant species. The presented study investigates this in a nutrient and species poor ecosystem. The study presents a methodology for inferring competitive interactions from yearly vegetation inventories...... by initial dominance of D. flexuosa. The observed inter-annual variability in climatic conditions (summer precipitation and soil water content) affected both species in a similar way and did not substantially alter the competitive balance between the species. Our study supports the “successional mosaic...

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

    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...

  15. Relative resource abundance explains butterfly biodiversity in island communities

    Yamamoto, Naoaki; Yokoyama, Jun; Kawata, Masakado

    2007-01-01

    Ecologists have long been intrigued by the factors that control the pattern of biodiversity, i.e., the distribution and abundance of species. Previous studies have demonstrated that coexisting species partition their resources and/or that the compositional similarity between communities is determined by environmental factors, lending support to the niche-assembly model. However, no attempt has been made to test whether the relative amount of resources that reflects relative niche space contro...

  16. Demonstrating That Habitat Structure Facilitates Coexistence of Prey & Predator: A Laboratory Investigation Using Goldfish & Invertebrates.

    Stewart, Timothy W.; Embrey, Tracey R.

    2003-01-01

    Presents a laboratory investigation to demonstrate that habitat structure promotes increased organism abundance and species diversity by reducing predator effects on prey abundance. Investigates the effects of goldfish (Carassius auratus) predators on Gammarus sp. (an amphipod) and Daphnia magna (a cladoceran) prey in the absence and presence of a…

  17. Precision Chemical Abundance Measurements

    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...

  18. Maximum abundant isotopes correlation

    The neutron excess of the most abundant isotopes of the element shows an overall linear dependence upon the neutron number for nuclei between neutron closed shells. This maximum abundant isotopes correlation supports the arguments for a common history of the elements during nucleosynthesis. (Auth.)

  19. The global stability of coexisting equilibria for three models of mutualism.

    Georgescu, Paul; Zhang, Hong; Maxin, Daniel

    2016-02-01

    We analyze the dynamics of three models of mutualism, establishing the global stability of coexisting equilibria by means of Lyapunov's second method. This further establishes the usefulness of certain Lyapunov functionals of an abstract nature introduced in an earlier paper. As a consequence, it is seen that the use of higher order self-limiting terms cures the shortcomings of Lotka-Volterra mutualisms, preventing unbounded growth and promoting global stability. PMID:26776263

  20. Bulk eutectic Cu–Ag alloys with abundant twin boundaries

    Abundant growth twin boundaries are found and characterized in two bulk eutectic Cu–Ag alloys that can be obtained conveniently. The statistical electron backscattering diffraction results show that both hetero-twin and cube-on-cube orientation relationships coexist in the eutectic Cu–Ag alloy. The tensile strength of the eutectic alloy increases with a decrease in the layer thickness of the Cu/Ag phase. This study provides a potential way to produce bulk eutectic Cu–Ag alloy with abundant twin boundaries that offers a combination of high strength and high ductility.

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

    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.

  2. Coexisting typical migraine in familial hemiplegic migraine

    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....

  3. Inter-WBAN Coexistence and Interference Mitigation

    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.

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

    Fontanari, José F; Serva, Maurizio

    2014-03-01

    The compartmentalization of distinct templates in protocells and the exchange of templates between them (migration) are key elements of a modern scenario for prebiotic evolution. Here we use the diffusion approximation of population genetics to study analytically the steady-state properties of such a prebiotic scenario. The coexistence of distinct template types inside a protocell is achieved by a selective pressure at the protocell level (group selection) favoring protocells with a mixed template composition. In the degenerate case, where the templates have the same replication rate, we find that a vanishingly small migration rate suffices to eliminate the segregation effect of random drift and so to promote coexistence. In the nondegenerate case, a small migration rate greatly boosts coexistence as compared with the situation where there is no migration. However, increase of the migration rate beyond a critical value leads to the complete dominance of the more efficient template type (homogeneous regime). In this case, we find a continuous phase transition separating the homogeneous and the coexistence regimes, with the order parameter vanishing linearly with the distance to the transition point. PMID:24619806

  5. The shape of terrestrial abundance distributions.

    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. PMID:26601249

  6. Abiotic vs. biotic influences on habitat selection of coexisting species: Climate change impacts?

    Martin, T.E.

    2001-01-01

    Species are commonly segregated along gradients of microclimate and vegetation. I explore the question of whether segregation is the result of microhabitat partitioning (biotic effects) or choice of differing microclimates (abiotic effects). I explored this question for four ground-nesting bird species that are segregated along a microclimate and vegetation gradient in Arizona. Birds shifted position of their nests on the microhabitat and microclimate gradient in response to changing precipitation over nine years. Similarly, annual bird abundance varied with precipitation across 12 yr. Those shifts in abundance and nesting microhabitat with changing precipitation demonstrate the importance of abiotic influences on bird distributions and habitat choice. However, nest-site shifts and microhabitat use also appear to be influenced by interactions among coexisting species. Moreover, shifts in habitat use by all species caused nest predation (i.e., biotic) costs that increased with increasing distance along the microclimate gradient. These results indicate that abiotic and biotic costs can strongly interact to influence microhabitat choice and abundances of coexisting species. Global climate change impacts have been considered largely in terms of simple distributional shifts, but these results indicate that shifts can also increase biotic costs when species move into habitat types for which they are poorly adapted or that create new biotic interactions.

  7. How can flexibility be integrated into coexistence regulations? A review.

    Devos, Yann; Dillen, Koen; Demont, Matty

    2014-02-01

    Member states in the European Union (EU) implemented both ex ante coexistence regulations and ex post liability schemes to ensure that genetically modified (GM) and non-GM crops can be cultivated side by side without excluding any agricultural option. Although proportionate coexistence is best achieved if regulated in a flexible manner, most implemented coexistence regulations merely rely on rigid measures. Flexible coexistence regulations, however, would reduce the regulatory burden on certain agricultural options and avoid jeopardizing economic incentives for coexistence. Flexibility can be integrated at: (i) the regulatory level by relaxing the rigidity of coexistence measures in ex ante regulations, yet without offsetting incentives to implement coexistence measures; (ii) the farm level by recommending the use of pollen barriers instead of large and fixed isolation distances; and (iii) the national/regional level by allowing diversified coexistence measures, which are adapted to the heterogeneity of farming in the EU. Owing to difficulties of implementation, the adoption of flexible and proportionate coexistence regulations will inevitably entail challenges. PMID:23965758

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

    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.

  9. Shape coexistence: the shell model view

    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).

  10. Surgical consequences in coexisting cataract and glaucoma.

    Blumenthal, M; Glovinsky, Y

    1995-04-01

    Of the three classical approaches to surgery for coexisting cataract and glaucoma, last year's publications dealt with the surgical consequences of combined cataract and glaucoma operations only. When used in combined cataract and glaucoma surgery, a small-incision extracapsular cataract extraction (ECCE) with phacoemulsification (PHACO) was found to be only slightly superior to the standard manual ECCE in terms of postoperative intraocular pressure (IOP) control. Injections of 5-fluorouracil postoperatively did not improve IOP control in PHACO-ECCE-trabeculectomy or manual ECCE-trabeculectomy. A preliminary uncontrolled report suggests, however, that intraoperative mitomycin C application in PHACO-ECCE-trabeculectomy may result in excellent postoperative IOP control without antiglaucomatous medications, and with no significant mitomycin C-related complications. Controlled studies on mitomycin C application in small-incision cataract and glaucoma surgery are needed to assess its long-term effect on IOP and astigmatism. PMID:10150852

  11. Coexistence of peptides with classical neurotransmitters.

    Hökfelt, T; Millhorn, D; Seroogy, K; Tsuruo, Y; Ceccatelli, S; Lindh, B; Meister, B; Melander, T; Schalling, M; Bartfai, T

    1987-07-15

    In the present article the fact is emphasized that neuropeptides often are located in the same neurons as classical transmitters such as acetylcholine, 5-hydroxy-tryptamine, catecholamines, gamma-aminobutyric acid (GABA) etc. This raises the possibility that neurons produce, store and release more than one messenger molecule. The exact functional role of such coexisting peptides is often difficult to evaluate, especially in the central nervous system. In the periphery some studies indicate apparently meaningful interactions of different types with the classical transmitter, but other types of actions including trophic effects have been observed. More recently it has been shown that some neurons contain more than one classical transmitter, e.g. 5-HT plus GABA, further underlining the view that transfer of information across synapses may be more complex than perhaps hitherto assumed. PMID:2885215

  12. Coexistence of pheochromocytoma with uncommon vascular lesions

    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.

  13. Orion A helium abundance

    The 22.4-GHz (H,He)66-alpha and 36.5-GHz (H,He)56-alpha radio recombination lines have been observed at several Jaffe-Pankonin positions in the central part of the Orion A source. The measured relative abundance of ionized helium increases with distance, averaging 11.6 percent at peripheral points. The observed behavior is interpreted by a blister-type model nebula, which implies that Orion A has a true He abundance of 12 percent, is moving with a radial velocity of 5 km/sec, and is expanding. 18 references

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

    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. PMID:25548732

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

    Morena Avitia

    2014-12-01

    Full Text Available 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. Indirect interactions among tropical tree species through shared rodent seed predators: a novel mechanism of tree species coexistence.

    Garzon-Lopez, Carol X; Ballesteros-Mejia, Liliana; Ordoñez, Alejandro; Bohlman, Stephanie A; Olff, Han; Jansen, Patrick A

    2015-08-01

    The coexistence of numerous tree species in tropical forests is commonly explained by negative dependence of recruitment on the conspecific seed and tree density due to specialist natural enemies that attack seeds and seedlings ('Janzen-Connell' effects). Less known is whether guilds of shared seed predators can induce a negative dependence of recruitment on the density of different species of the same plant functional group. We studied 54 plots in tropical forest on Barro Colorado Island, Panama, with contrasting mature tree densities of three coexisting large seeded tree species with shared seed predators. Levels of seed predation were far better explained by incorporating seed densities of all three focal species than by conspecific seed density alone. Both positive and negative density dependencies were observed for different species combinations. Thus, indirect interactions via shared seed predators can either promote or reduce the coexistence of different plant functional groups in tropical forest. PMID:25939379

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

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

  18. Geometry of coexistence in the interacting boson model

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

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

    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.…

  20. Coexisting Disorders and Academic Achievement among Children with ADHD

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

    2011-01-01

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

  1. The challenges of managing coexistent disorders with phenylketonuria

    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.......-centre, retrospective cohort study. METHODS: Diagnostic age of PKU and co-existent condition, treatment regimen, and impact of co-existent condition on blood phenylalanine (Phe) control and PKU management were reported. RESULTS: 30 patients (11 males and 19 females), with PKU and a co-existent condition, current median......-existent conditions adversely affected blood Phe control in 47% (n=14) of patients. Some co-existent conditions increased the complexity of disease management and increased management burden for patients and caregivers. CONCLUSIONS: Occurrence of co-existent disease is not uncommon in patients with PKU and so...

  2. Living with Lions: The Economics of Coexistence in the Gir Forests, India

    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 km2. Livestock density, estimated by total counts, ranged between 25/km2–31/km2 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

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

    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.

  4. Aggression and coexistence in female caribou

    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.

  5. Shape coexistence and evolution in 98Sr

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

    2016-01-01

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

  6. A pedagogy of abundance

    Weller, Martin

    2011-01-01

    The digitisation of content combined with a global network for delivery and an open system for sharing has seen radical changes in many industries. The economic model which has underpinned many content based industries has been based on an assumption of scarcity. With a digital, open, networked approach we are witnessing a shift to abundance of content, and subsequently new economic models are being developed which have this as an assumption. In this article the role of scarcity in developing...

  7. Interstellar Atomic Abundances

    Jenkins, E B

    2003-01-01

    A broad array of interstellar absorption features that appear in the ultraviolet spectra of bright sources allows us to measure the abundances and ionization states of many important heavy elements that exist as free atoms in the interstellar medium. By comparing these abundances with reference values in the Sun, we find that some elements have abundances relative to hydrogen that are approximately consistent with their respective solar values, while others are depleted by factors that range from a few up to around 1000. These depletions are caused by the atoms condensing into solid form onto dust grains. Their strengths are governed by the volatility of compounds that are produced, together with the densities and velocities of the gas clouds. We may characterize the depletion trends in terms of a limited set of parameters; ones derived here are based on measurements of 15 elements toward 144 stars with known values of N(H I) and N(H2). In turn, these parameters may be applied to studies of the production, de...

  8. Abundances in galaxies

    Standard (or mildly inhomogeneous) Big Bang nucleosynthesis theory is well confirmed by abundance measurements of light elements up to 7Li and the resulting upper limit to the number of neutrino families confirmed in accelerator experiments. Extreme inhomogeneous models with a closure density in form of baryons seem to be ruled out and there is no evidence for a cosmic 'floor' to 9Be or heavier elements predicted in some versions of those models. Galaxies show a correlation between luminous mass and abundance of carbon and heavier elements, usually attributed to escape of hot gas from shallow potential wells. Uncertainties include the role of dark matter and biparametric behaviour of ellipticals. Spirals have radial gradients which may arise from a variety of causes. In our own Galaxy one can distinguish three stellar populations - disk, halo and bulge - characterised by differing metallicity distribution functions. Differential abundance effects are found among different elements in stars as a function of metallicity and presumably age, notably in the ratio of oxygen and α-particle elements to iron. These may eventually be exploitable to set a time scale for the formation of the halo, bulge and disk. (orig.)

  9. Long-term coexistence of rotifer cryptic species.

    Javier Montero-Pau

    Full Text Available Despite their high morphological similarity, cryptic species often coexist in aquatic habitats presenting a challenge in the framework of niche differentiation theory and coexistence mechanisms. Here we use a rotifer species complex inhabiting highly unpredictable and fluctuating salt lakes to gain insights into the mechanisms involved in stable coexistence in cryptic species. We combined molecular barcoding surveys of planktonic populations and paleogenetic analysis of diapausing eggs to reconstruct the current and historical coexistence dynamics of two highly morphologically similar rotifer species, B. plicatilis and B. manjavacas. In addition, we carried out laboratory experiments using clones isolated from eight lakes where both species coexist to explore their clonal growth responses to salinity, a challenging, highly variable and unpredictable condition in Mediterranean salt lakes. We show that both species have co-occurred in a stable way in one lake, with population fluctuations in which no species was permanently excluded. The seasonal occurrence patterns of the plankton in two lakes agree with laboratory experiments showing that both species differ in their optimal salinity. These results suggest that stable species coexistence is mediated by differential responses to salinity and its fluctuating regime. We discuss the role of fluctuating salinity and a persistent diapausing egg banks as a mechanism for species coexistence in accordance with the 'storage effect'.

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

    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.

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

    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. PMID:27277402

  12. The coexistence of seven sympatric fulvettas in Ailao Mountains, Ejia Town, Yunnan Province.

    Xia, Ji; Wu, Fei; Hu, Wan-Zhao; Fang, Jian-Ling; Yang, Xiao-Jun

    2015-01-18

    The coexistence of ecologically similar species sharing sympatric areas is a central issue of community ecology. Niche differentiation is required at least in one dimension to avoid competitive exclusion. From 2012-2014, by adopting the methods of mist-nets and point counts to evaluate spatial niche partitioning and morphological differentiations, we explored the coexistence mechanisms of seven sympatric fulvettas in Ailao Mountains, Ejia town, Yunnan Province, China. The microhabitats of these seven fulvettas were significantly different in elevation, roost site height and vegetation coverage, indicating a spatial niche segregation in different levels. Approximately, 90.30% of the samples were correctly classified by linear discriminant analysis (LDA) with correct rates at 91.20%-100%, except the White-browed fulvetta (Alcippe vinipectus) (65.4%) and the Streak-throated fulvetta (A. cinereiceps) (74.6%). The seven fulvettas were classified into four guilds based on their specific morphological characters, suggesting that the species in each guild use their unique feeding ways to realize resource partitioning in the overlapped areas. These finding indicate that through multi-dimensional spatial niche segregation and divergence in resource utilizing, the inter-specific competition among these seven fulvettas is minimized, whereas, coexistence is promoted. PMID:25730457

  13. Antibiotics promote aggregation within aquatic bacterial communities.

    Corno, Gianluca; Coci, Manuela; Giardina, Marco; Plechuk, Sonia; Campanile, Floriana; Stefani, Stefania

    2014-01-01

    The release of antibiotics (AB) into the environment poses several threats for human health due to potential development of AB-resistant 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 the effects of AB

  14. Species-specific traits plus stabilizing processes best explain coexistence in biodiverse fire-prone plant communities.

    Jürgen Groeneveld

    Full Text Available Coexistence in fire-prone Mediterranean-type shrublands has been explored in the past using both neutral and niche-based models. However, distinct differences between plant functional types (PFTs, such as fire-killed vs resprouting responses to fire, and the relative similarity of species within a PFT, suggest that coexistence models might benefit from combining both neutral and niche-based (stabilizing approaches. We developed a multispecies metacommunity model where species are grouped into two PFTs (fire-killed vs resprouting to investigate the roles of neutral and stabilizing processes on species richness and rank-abundance distributions. Our results show that species richness can be maintained in two ways: i strictly neutral species within each PFT, or ii species within PFTs differing in key demographic properties, provided that additional stabilizing processes, such as negative density regulation, also operate. However, only simulations including stabilizing processes resulted in structurally realistic rank-abundance distributions over plausible time scales. This result underscores the importance of including both key species traits and stabilizing (niche processes in explaining species coexistence and community structure.

  15. Species-specific traits plus stabilizing processes best explain coexistence in biodiverse fire-prone plant communities.

    Groeneveld, Jürgen; Enright, Neal J; Lamont, Byron B; Reineking, Björn; Frank, Karin; Perry, George L W

    2013-01-01

    Coexistence in fire-prone Mediterranean-type shrublands has been explored in the past using both neutral and niche-based models. However, distinct differences between plant functional types (PFTs), such as fire-killed vs resprouting responses to fire, and the relative similarity of species within a PFT, suggest that coexistence models might benefit from combining both neutral and niche-based (stabilizing) approaches. We developed a multispecies metacommunity model where species are grouped into two PFTs (fire-killed vs resprouting) to investigate the roles of neutral and stabilizing processes on species richness and rank-abundance distributions. Our results show that species richness can be maintained in two ways: i) strictly neutral species within each PFT, or ii) species within PFTs differing in key demographic properties, provided that additional stabilizing processes, such as negative density regulation, also operate. However, only simulations including stabilizing processes resulted in structurally realistic rank-abundance distributions over plausible time scales. This result underscores the importance of including both key species traits and stabilizing (niche) processes in explaining species coexistence and community structure. PMID:23734234

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

    Rutherford, Alex; Harmon, Dion; Werfel, Justin; Gard-Murray, Alexander S; Bar-Yam, Shlomiya; Gros, Andreas; Xulvi-Brunet, Ramon; Bar-Yam, Yaneer

    2014-01-01

    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, allowing for partial autonomy within a single country. In Switzerland, mountains and lakes are an important part of the boundaries between sharply defined linguistic areas. Political canton and circle (sub-canton) boundaries often separate religious groups. Where such boundaries do not appear to be sufficient, we find that specific aspects of the population distribution guarantee either sufficient separation or sufficient mixing to inhibit intergroup violence according to the quantitative theory of conflict. In exactly one region, a porous mountain range does not adequately separate linguistic groups and that region has experienced significant violent conflict, leading to the recent creation of the canton of Jura. Our analysis supports the hypothesis that violence between groups can be inhibited by physical and political boundaries. A similar analysis of the area of the former Yugoslavia shows that during widespread ethnic violence existing political boundaries did not coincide with the boundaries of distinct groups, but peace prevailed in specific areas where they did coincide. The success of peace in Switzerland may serve as a model to resolve conflict in other ethnically diverse countries and regions of the world. PMID:24847861

  17. Coexisting HLA-B27 positive spondyloarthritis and polyarteritis nodosa.

    Sattar, M A

    1992-01-01

    A 38 year old woman presented with widespread polyarteritis nodosa a few years after the onset of HLA-B27 positive spondyloarthritis. The concomitant coexistence of these two disorders suggests a possible association in this genetically susceptible subject.

  18. Water Resources Management. Coexistence and Conflict in Semiarid Brazil

    Thiago Ferreira Dias; Daniel Araújo Valença; Iriane Teresa de Araújo; Rayane Cristina de Andrade Gomes; Ronaldo Moreira Maia Jr

    2016-01-01

    The paper analyzes water management in the Brazilian semiarid region with emphasis on aspects of coexistence and conflicts over access in rural areas. Experiences of social coexistence in semiarid technologies from the joint to the Brazilian semiarid (ASA) and water conflicts from cases of irrigated areas in the states of Ceará and Rio Grande do Norte are explained. For this purpose, we used a qualitative approach through the use of primary and secondary data. The cases provide concrete actio...

  19. Can open access repositories and peer-reviewed journals coexist?

    Pinfield, Stephen

    2007-01-01

    It is often assumed that open access repositories and peer-reviewed journals are in competition with each other and therefore will in the long term be unable to coexist. This paper takes a critical look at that assumption. It draws on the available evidence of actual practice which indicates that coexistence is possible at least in the medium term. It discusses possible future models of publication and dissemination which include open access, repositories, peer review and journals. The paper ...

  20. Coexistence of ferromagnetism and superconductivity in semimetals (Triplet pairing case)

    The possibility of coexistence of ferromagnetic ordering and superconductivity in a two-band model of a semimetal with an isotopic current carrier spectrum is investigated in detail. It is shown that for unequal electron and hole concentrations triplet electron-hole and triplet cooper pairings with weak electron coupling may coexist. In this case a nonvanishing mean magnetic moment appears. (author). 9 refs., 4 figs

  1. Coexisting Order in the Pseudogap State of Cuprates

    P. Bhattacharyya

    2007-01-01

    A pseudogap is shown to be a magnetic diffuson (MD) in a state with classical localization order coexisting with Quantum Peierls (QP) order. A soft quantum localization mode, a phason, ensures scale invariance with strong correlations among different momentum states seen as a circular Fermi surface with a gap in ARPES when phase fluctuations are random. These correlations imply a state with coexisting order parameters at distinct length scales. Charge quantization and scale invariance account...

  2. Coexistence of charge and ferromagnetic order in fcc Fe

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

    2016-01-01

    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...

  3. Coexistence among Epiphytic Bacterial Populations Mediated through Nutritional Resource Partitioning

    Wilson, Mark; Lindow, Steven E.

    1994-01-01

    The levels of coexistence between Pseudomonas syringae and various nonpathogenic epiphytic species in the phyllosphere of beans (Phaseolus vulgaris) were assessed by using replacement series. The epiphytic species Pseudomonas fluorescens, Pantoea agglomerans, Stenotrophomonas maltophilia, and Methylobacterium organophilum were all capable of exhibiting higher levels of coexistence with P. syringae than was observed with a near-isogenic P. syringae strain pair. The ecological similarity of the...

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

    Lijun Qian; Oluwaseyi Omotere; Riku Jäntti

    2015-01-01

    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, a...

  5. Multiple myeloma presenting with coexisting severe marrow hypoplasia

    Medhi K; Kalita Dipti; Chopra Anita; Anand Mona; Raina Vinod; Kumar Rajive

    2008-01-01

    A 68-year-old man was referred to us with clinical and bone marrow (BM) features compatible with aplastic anemia. The correct diagnosis, hypoplasia of the BM coexisting with multiple myeloma, became apparent after noting rouleaux in the peripheral blood (PB) and approximately 50% plasma cells in the touch imprint of one of the two BM biopsies done. As standard therapy was precluded, the patient was put on dexamethasone but died within 4 days. This first case of the coexistence of untre...

  6. Abundance, Excess, Waste

    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.

  7. Coexistence of species with different dispersal across landscapes: a critical role of spatial correlation in disturbance.

    Liao, Jinbao; Ying, Zhixia; Woolnough, Daelyn A; Miller, Adam D; Li, Zhenqing; Nijs, Ivan

    2016-05-11

    Disturbance is key to maintaining species diversity in plant communities. Although the effects of disturbance frequency and extent on species diversity have been studied, we do not yet have a mechanistic understanding of how these aspects of disturbance interact with spatial structure of disturbance to influence species diversity. Here we derive a novel pair approximation model to explore competitive outcomes in a two-species system subject to spatially correlated disturbance. Generally, spatial correlation in disturbance favoured long-range dispersers, while distance-limited dispersers were greatly suppressed. Interestingly, high levels of spatial aggregation of disturbance promoted long-term species coexistence that is not possible in the absence of disturbance, but only when the local disperser was intrinsically competitively superior. However, spatial correlation in disturbance led to different competitive outcomes, depending on the disturbed area. Concerning ecological conservation and management, we theoretically demonstrate that introducing a spatially correlated disturbance to the system or altering an existing disturbance regime can be a useful strategy either to control species invasion or to promote species coexistence. Disturbance pattern analysis may therefore provide new insights into biodiversity conservation. PMID:27147101

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

    Dechesne, Arnaud; Or, Dani; Smets, Barth F

    2008-04-01

    Soils are known to support a great bacterial diversity down to the millimeter scale, but the mechanisms by which such a large diversity is sustained are largely unknown. A feature of unsaturated soils is that water usually forms thin, poorly-connected films, which limit solute diffusive fluxes. It has been proposed, but never unambiguously experimentally tested, that a low substrate diffusive flux would impact bacterial diversity, by promoting the coexistence between slow-growing bacteria and their potentially faster-growing competitors. We used a simple experimental system, based on a Petri dish and a perforated Teflon membrane to control diffusive fluxes of substrate (benzoate) whilst permitting direct observation of bacterial colonies. The system was inoculated with prescribed strains of Pseudomonas, whose growth was quantified by microscopic monitoring of the fluorescent proteins they produced. We observed that substrate diffusion limitation reduced the growth rate of the otherwise fast-growing Pseudomonas putida KT2440 strain. This strain out-competed Pseudomonas fluorescens F113 in liquid culture, but its competitive advantage was less marked on solid media, and even disappeared under conditions of low substrate diffusion. Low diffusive fluxes of substrate, characteristic of many unsaturated media (e.g. soils, food products), can thus promote bacterial coexistence in a competitive situation between two strains. This mechanism might therefore contribute to maintaining the noncompetitive diversity pattern observed in unsaturated soils. PMID:18312376

  9. Fostering the coexistence of caring philosophy and economics in today's health care system.

    Cara, Chantal M; Nyberg, Jan J; Brousseau, Sylvain

    2011-01-01

    For the past decade, several health care systems are undergoing continuous administrative restructuring, whose main objective is cost reduction. These changes often result in the patients' needs not being met because nurses are continuously affected by widespread budget cuts and staff downsizing. Have we reached a point, where we are setting aside our prime directive of patient well-being for the sake of finances? If so, are we at risk of forsaking our professional identity as nurses? The authors believe that caring management and economical constraints can coexist while promoting quality patient care. The purpose of this article is to show how nurse managers and administrators can facilitate caring practices while maintaining their financial responsibilities within the health care organization. This article suggests several strategies for assisting nurse managers in promoting caring in the health care environment. PMID:21157259

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

    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. PMID:26341209

  11. The primordial helium abundance from updated emissivities

    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...

  12. Habitat filtering and niche differentiation jointly explain species relative abundance within grassland communities along fertility and disturbance gradients.

    Maire, Vincent; Gross, Nicolas; BORGER, Luca; Proulx, Raphaël; Wirth, Christian; Da Silveira Pontes, Laise; Soussana, Jean-François; Louault, Frédérique

    2012-01-01

    Deterministic niche-based processes have been proposed to explain species relative abundance within communities but lead to different predictions: habitat filtering (HF) predicts dominant species to exhibit similar traits while niche differentiation (ND) requires that species have dissimilar traits to coexist. Using a multiple trait-based approach, we evaluated the relative roles of HF and ND in determining species abundances in productive grasslands. Four dimensions of the functional niche o...

  13. Primordial Deuterium Abundance Measurements

    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.

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

    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.

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

    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. PMID:24325257

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

    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)HDTYAT0018-067X10.1038/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. PMID:27300918

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

    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.

  18. Shape coexistence and phase transitions in the platinum isotopes

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

  19. Evolution of Dispersal with Starvation Measure and Coexistence.

    Kim, Yong-Jung; Kwon, Ohsang

    2016-02-01

    Many biological species increase their dispersal rate if starvation starts. To model such a behavior, we need to understand how organisms measure starvation and response to it. In this paper, we compare three different ways of measuring starvation by applying them to starvation-driven diffusion. The evolutional selection and coexistence of such starvation measures are studied within the context of Lotka-Volterra-type competition model of two species. We will see that, if species have different starvation measures and different motility functions, both the coexistence and selection are possible. PMID:26817757

  20. Shape coexistence and triaxiality in nuclei near 80Zr

    Zheng, S J; Shen, S F; Liu, H L; Wyss, R

    2013-01-01

    Total-Routhian-Surface calculations have been performed to investigate the shape evolutions of $A\\sim80$ nuclei, $^{80-84}$Zr, $^{76-80}$Sr and $^{84,86}$Mo. Shape coexistences of spherical, prolate and oblate deformations have been found in these nuclei. Particularly for the nuclei, $^{80}$Sr and $^{82}$Zr, the energy differences between two shape-coexisting states are less than 220 keV. At high spins, the $g_{9/2}$ shell plays an important role for shape evolutions. It has been found that the alignment of the $g_{9/2}$ quasi-particles drives nuclei to be triaxial.

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

    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. PMID:27346439

  2. Solar System Abundances of the Elements

    Lodders, Katharina

    2010-01-01

    Representative abundances of the chemical elements for use as a solar abundance standard in astronomical and planetary studies are summarized. Updated abundance tables for solar system abundances based on meteorites and photospheric measurements are presented.

  3. The primordial helium abundance from updated emissivities

    Observations of metal-poor extragalactic H II regions allow the determination of the primordial helium abundance, Yp. 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 Yp. 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 Yp = 0.2465 ± 0.0097, in good agreement with the BBN result, Yp = 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. Coexistence of two species in a strongly coupled cooperating model

    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...

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

    Kumar, Rupesh; Qin, Hao; Alléaume, Romain

    2015-04-01

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

  6. Coexisting cyclic parthenogens comprise a holocene species flock in Eubosmina.

    Markéta Faustová

    Full Text Available BACKGROUND: Mixed breeding systems with extended clonal phases and weak sexual recruitment are widespread in nature but often thought to impede the formation of discrete evolutionary clusters. Thus, cyclic parthenogens, such as cladocerans and rotifers, could be predisposed to "species problems" and a lack of discrete species. However, species flocks have been proposed for one cladoceran group, Eubosmina, where putative species are sympatric, and there is a detailed paleolimnological record indicating a Holocene age. These factors make the Eubosmina system suitable for testing the hypotheses that extended clonal phases and weak sexual recruitment inhibit speciation. Although common garden experiments have revealed a genetic component to the morphotypic variation, the evolutionary significance of the morphotypes remains controversial. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, we tested the hypothesis of a single polymorphic species (i.e., mixing occurs but selection maintains genes for morphology in four northern European lakes where the morphotypes coexist. Our evidence is based on nuclear DNA sequence, mitochondrial DNA sequence, and morphometric analysis of coexisting morphotypes. We found significant genetic differentiation, genealogical exclusivity, and morphometric differentiation for coexisting morphotypes. CONCLUSIONS: We conclude that the studied morphotypes represent a group of young species undergoing speciation with apparent reproductive barriers despite coexistence in the freshwater pelagic zone.

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

    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....

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

    2013-11-04

    ... Office of the Secretary Enhancing Agricultural Coexistence; Request for Public Input ACTION: Request for... (5) seed quality. In the area of education and outreach, we are seeking public input regarding the.... Following the comment period, USDA intends to hold a public forum to discuss input provided by...

  9. Coulomb excitation studies of shape coexistence in atomic nuclei

    Görgen, Andreas; Korten, Wolfram

    2016-02-01

    Low-energy Coulomb excitation provides a well-understood means of exciting atomic nuclei and allows measuring electromagnetic moments that can be directly related to the nuclear shape. The availability of radioactive ion beams (RIBs) at energies near the Coulomb barrier has made it possible to study shape coexistence in a variety of short-lived exotic nuclei. This review presents a short overview of the methods related to multi-step Coulomb excitation experiments, followed by a discussion of several examples. The focus is on two mass regions where recent Coulomb excitation experiments have contributed to the quantitative understanding of shape coexistence: nuclei with mass A≈ 70 near the N = Z line and nuclei with A ≈ 100 near neutron number N = 60. Experimental results are summarized and their significance for understanding shape coexistence is discussed. Experimental observables such as quadrupole moments and electromagnetic transition strengths represent furthermore important benchmarks for advancing theoretical nuclear structure models. With several new RIB facilities planned and under construction, Coulomb excitation will remain to be an important tool to extend the studies of nuclear shapes toward more exotic systems, and to obtain a more comprehensive and quantitative understanding of shape coexistence.

  10. Tracking the Roundup Ready® gene: implications for coexistence

    The USDA has been conducting research to address concerns voiced by the alfalfa industry regarding the coexistence of genetically engineered and non-GE alfalfa seed production. In 2011 a survey was conducted to get a baseline estimate of the presence of transgenic roadside alfalfa plants. We surveye...

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

    Wu Haitao

    2006-01-01

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

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

    Hong, Young Min; Moon, Jin Chang; Yang, Hee Chan; Kang, Kyung Pyo; Kim, Won; Park, Sung Kwang; Lee, Sik

    2012-01-01

    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.

  13. Coexistence of a General Elliptic System in Population Dynamics

    Pedersen, Michael

    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...

  14. Emissions Trading and Promotion of Renewable Energy: We Need Both

    Claudia Kemfert; Jochen Diekmann

    2009-01-01

    Emissions trading and the promotion of the use of energy from renewable sources are key elements of German and European energy and climate policy. However, some critics oppose a targeted promotion of renewable energy, arguing in particular that this is ineffective or even damaging in conjunction with European emissions trading. Yet upon closer examination, the coexistence of emissions trading and promotion of renewable energy is not only possible, it is essential-provided the interactions bet...

  15. The coexistence of species La coexistencia de especies

    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

  16. Estimating Animal Abundance: Review III

    Schwarz, Carl J; Seber, George A. F.

    1999-01-01

    The literature describing methods for estimating animal abundance and related parameters continues to grow. This paper reviews recent developments in the subject over the past seven years and updates two previous reviews.

  17. Chlorine Abundances in Cool Stars

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

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

    2016-01-01

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

  19. Possible Coexistence of Antihydrogen with Hydrogen, Deuterium and Tritium Atoms

    Abdel-Raouf, Mohamed Assad

    2007-01-01

    Recent productions of large numbers of cold antiprotons as well as the formation of antihydrogens at CERN and Fermilab have raised basic questions about possible coexistence of matter and antimatter in nature. In the present work, previous mathematical considerations are revisited which support the possible coexistence of Antihydrogen with Hydrogen, Deuterium and Tritium atoms. In particular, the main objective of the present work is to present computational treatments which confirm the possible formation of these quasi molecules in laboratory. These treatments are based on a nonadiabatic picture of the system in which generalized basis functions are adjusted within the framework of Rayleigh-Ritz' variational method. Thus, the Born-Oppenheimer adiabatic picture of the system, which implies the formation of exotic molecules composed explicitly of fixed quasi heavy atoms (containing at least two leptons, e.g. protonium) and quasi light atoms (e.g. positronium), is ruled out in the present work. In other words, ...

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

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

    2014-01-01

    Four krill species with overlapping functional biology coexist in Greenland waters. Here, we used stable isotopes to investigate and discuss their trophic role and mode of coexistence. Bulk carbon (δ13C) and nitrogen (δ15N) stable isotope analyses of Thysanoessa longicaudata, T. inermis, T. raschii...... and Meganyctiphanes norvegica sampled in June 2010 in the Godthåbsfjord, SW Greenland revealed new insight into their trophic roles and positions. There was a general positive correlation between body length and trophic position. The largest species M. norvegica had the highest trophic position (TP...... = 2.8 ± 0.2) indicating carnivory, while T. inermis (TP = 2.4 ± 0.3) had a more omnivorous diet. In turn, T. longicaudata and T. raschii (TP = 2.2 ± 0.2) were herbivorous. Along the fjord, nutrient and plankton composition affected trophic position. Thysanoessa longicaudata was more omnivorous...

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

    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. Time scales and species coexistence in chaotic flows

    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.

  3. Ecology 2.0: Coexistence and Domination of Interacting Networks

    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...

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

    Nitin Tangri

    2014-01-01

    Full Text Available 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.

  5. Coexistence of pheochromocytoma/praganglioma and renal artery stenosis

    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.

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

    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.

  7. On channel selection and shape co-existence

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

  8. Multiple myeloma presenting with coexisting severe marrow hypoplasia.

    Medhi, K; Kalita, Dipti; Chopra, Anita; Anand, Mona; Raina, Vinod; Kumar, Rajive

    2008-01-01

    A 68-year-old man was referred to us with clinical and bone marrow (BM) features compatible with aplastic anemia. The correct diagnosis, hypoplasia of the BM coexisting with multiple myeloma, became apparent after noting rouleaux in the peripheral blood (PB) and approximately 50% plasma cells in the touch imprint of one of the two BM biopsies done. As standard therapy was precluded, the patient was put on dexamethasone but died within 4 days. This first case of the coexistence of untreated myeloma with aplastic BM shows that even apparently straightforward hypoplasia seen on the BM biopsy should be interpreted in conjunction with the PB smear and the BM touch imprint findings. Among other things, the BM biopsy and imprint should be repeated if the PB has findings such as rouleaux that do not fit with straightforward aplastic anemia. The combination of myeloma and BM aplasia precludes standard therapy and is rapidly fatal. PMID:19008591

  9. Multiple myeloma presenting with coexisting severe marrow hypoplasia

    Medhi K

    2008-10-01

    Full Text Available A 68-year-old man was referred to us with clinical and bone marrow (BM features compatible with aplastic anemia. The correct diagnosis, hypoplasia of the BM coexisting with multiple myeloma, became apparent after noting rouleaux in the peripheral blood (PB and approximately 50% plasma cells in the touch imprint of one of the two BM biopsies done. As standard therapy was precluded, the patient was put on dexamethasone but died within 4 days. This first case of the coexistence of untreated myeloma with aplastic BM shows that even apparently straightforward hypoplasia seen on the BM biopsy should be interpreted in conjunction with the PB smear and the BM touch imprint findings. Among other things, the BM biopsy and imprint should be repeated if the PB has findings such as rouleaux that do not fit with straightforward aplastic anemia. The combination of myeloma and BM aplasia precludes standard therapy and is rapidly fatal.

  10. What constitutes a convention? Implications for the coexistence of conventions

    Kolstad, Ivar

    2004-01-01

    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...

  11. Coexistence of Epileptic Nocturnal Wanderings and an Arachnoid Cyst

    Jiménez-Genchi, Alejandro; Díaz-Galviz, John L.; García-Reyna, Juan Carlos; Ávila-Ordoñez, Mario U.

    2007-01-01

    Episodic nocturnal wanderings (ENWs) have rarely been associated with gross abnormalities of brain structures. We describe the case of a patient with ENWs in coexistence with an arachnoid cyst (AC). The patient was a 15-year-old boy who presented with nocturnal attacks characterized by complex motor behaviors. An MRI revealed a left temporal cyst and a SPECT Tc99 scan showed left temporal hypoperfusion and bilateral frontal hyperperfusion, more evident on the right side.

  12. Inherent Shear-Dilatation Coexistence in Metallic Glass

    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.

  13. Coexistence of metallic and insulating-like states in graphene

    Fang Wu; Jing Huang; Qunxiang Li; Kaiming Deng; Erjun Kan

    2015-01-01

    Since graphene has been taken as the potential host material for next-generation electric devices, coexistence of high carrier mobility and an energy gap has the determining role in its real applications. However, in conventional methods of band-gap engineering, the energy gap and carrier mobility in graphene are seemed to be the two terminals of a seesaw, which limit its rapid development in electronic devices. Here we demonstrated the realization of insulating-like state in graphene without...

  14. Algebraic benchmark for prolate-oblate coexistence in nuclei

    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.

  15. Playing games to design GM/Non-GM coexistence scenarios

    Le Bail, Marianne; Lecroart, Baptiste; Remy, Brigitte; Sausse, Christophe

    2009-01-01

    Coexistence is an approach allowing farmers to choose between conventional and genetically modified (GM) crops and allowing consumers to choose between different food products subject to obligations regarding labelling and purity (European Commission, 2003). Some research have already been carried out to assess the risks of cross-pollination between GM and non-GM crops at field level, and the effect of individual measures to reduce those risks (Beckie and Hall 2008). Nonetheless, the feasibil...

  16. Co-existence of Organic and GM Agriculture

    Boelt, Birte

    2004-01-01

    The Danish Minister for Food, Agriculture and Fisheries presented in spring 2004 a bill on co-existence of genetically modified, conventional and organic crops in support of the free choice of consumers and to ensure development possibilities for new and existing production forms. The bill contains a framework for regulation based on crop specific control measures, communication among farmers and mandatory courses in GM cultivation. The identification of control measures is based on the repor...

  17. LIQUID-GAS COEXISTENCE EQUILIBRIUM IN A RELAXATION MODEL

    WANG Ping; TANG Shao-qiang

    2005-01-01

    Stability of liquid-gas coexistence equilibrium in a relaxation model for isothermal phase transition in a sealed one-dimensional tube was discussed. With matched asymptotic expansion, a linear system for first order perturbations was derived formally. By solving this system analytically, it is shown that small initial perturbations are damped out in general; yet they may maintain at certain level for special cases.Numerical evidence is presented. This manifests the regularization effects of relaxation.

  18. Coexistence of Quantum Theory and Special Relativity in signaling scenarios

    Sancho, Pedro

    2008-01-01

    The coexistence between Quantum Mechanics and Special Relativity is usually formulated in terms of the no-signaling condition. Several authors have even suggested that this condition should be included between the basic postulates of Quantum Theory. However, there are several scenarios where signaling is, in principle, possible: based on previous results and the analysis of the relation between unitarity and signaling we present an example of a two-particle interferometric arrangement for whi...

  19. Magnetic-phase coexistence in Nd7Rh3

    Magnetic studies on the intermetallic compound Nd7Rh3 indicate the existence of magnetic field induced first-order-phase-transition. Nd7Rh3 exhibits two magnetic transitions, at 32 K and 16 K. We have recently carried out detailed neutron diffraction studies on poly-crystalline Nd7Rh3 to establish, microscopically, the electronic phase coexistence in the zero field state after the system has been subjected to field cycling across the first-order-phase-transition. The evolution of the magnetic features was studied by recording and analyzing the neutron diffraction patterns at various temperatures across the magnetic ordering temperatures. We observe that below 20 K, there is coexistence of antiferromagnetic and ferromagnetic phases. We also observe that when the sample is cooled at 1.62 K in a magnetic field of 3 T, the first-order transition gets interrupted, resulting in the coexistence of magnetic phases whose fractions are dependent on the path and magnitude of the cooling field after carrying out the magnetic field cycling through the magnetic-field-induced magnetic transition, high-field magnetic st ate is partially present. The temperature and magnetic field dependent neutron diffraction study thus provides microscopic evidence for the kinetic arrest of the first-order magnetic transition and phase coexistence of antiferro- and ferromagnetic phases in Nd7Rh3 at temperatures well below its second magnetic transition temperature. The results of neutron diffraction experiments carried out as a function of temperature and magnetic field at various diffractometers, PD-3 at Dhruva, D1B and D2B at Institut Laue-Langevin and E6 at Helmholtz Zentrum Berlin will be presented and discussed. (author)

  20. Demographic Aspects of Coexistence in Engelmann Spruce and Subalpine Fir

    Shea, Kathleen L

    1985-01-01

    The mechanisms for the maintenance of coexistence of Engelmann spruce and subalpine fir in subalpine forests of the Colorado Front Range were examined by comparing age, size, and spatial distributions of spruce and fir in two adjacent, previously logged sites of differing moisture availability. Adult tree ages were calculated from stem cores, while seedling ages were calculated from a multiple regression equation based on diameter, height, and number of branch whorls. Tree size was measured b...

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

    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. PMID:24661692

  2. Coexistence of Pancreatic Carcinoma and Pancreatic Tuberculosis: Case Report

    Zheng, Zhen-Jiang; Zhang, Hao; Xiang, Guang-Ming; Gong, Jun; Mai, Gang; Liu, Xu-Bao

    2011-01-01

    Pancreatic tuberculosis (TB) is extremely rare and mimics pancreatic carcinoma both clinically and radiologically. This paper discusses the occurrence of 2 heterogeneous masses located in the head and tail of the pancreas in an adult male. In this patient, laparotomy was performed because of the high suspicion of pancreatic carcinoma. Intraoperative fine needle aspiration biopsy revealed the coexistence of pancreatic carcinoma with pancreatic TB, and a combined resection of the distal pancrea...

  3. CTSS activation coexists with CD40 activation in human atheroma

    Černe, Andreja; Kržišnik-Zorman, Simona; ZORMAN, Darko; Kranjec, Igor; Černe, Darko; Marc, Janja; Štern, Irma

    2015-01-01

    Objectives: By the analysis of plasma mRNA levels, we tested the hypothesis that, in human atheroma, CTSS activation coexists with activation of CD40. Design and methods: mRNAs were isolated from plasma of patients with coronary atherosclerosis and quantified by real-time RT-PCR. Results: CTSS mRNA levels correlated with CD40 mRNA levels, independently of observed traditional risk factors for atherosclerosis and pharmacological treatment. Conclusions: Our results suggest that CTSS mediated at...

  4. Coexistence of Spinal Intramedullary Tuberculoma and Multiple Intracranial Tuberculomas

    Lee, Dong-Yoon; Kim, Sang-Pyo; Kim, In-Soo

    2015-01-01

    Spinal intramedullary tuberculoma remains a very rare entity of central nervous system tuberculosis. This is the same with the coexistence of spinal intramedullary and intracranial tuberculomas that remains extremely rare with less than 20 cases reported at present. Authors describe this uncommon case by analyzing a 65-year-old female patient who had past history of kidney transplantation due to stage 5 chronic kidney disease and pulmonary tuberculosis on medication. The patient experiences p...

  5. Molar Pregnancy with a Co-Existing Viable Fetus

    Ruya Deveer

    2014-01-01

        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 preg...

  6. The concept of the Danish working group on coexistence

    BOELT, B.

    2005-01-01

    In the spring of 2002, the Danish Minister for Food, Agriculture and Fisheries initiated strategy work on the cultivation of authorised GM crops in Danish agriculture. The aim was to produce a Danish model for the co-existence of GM, conventional and organic crops in support of the free choice of consumers and to ensure development possibilities for new and existing agricultural production forms. Three groups were set up, that were assigned the task of presenting the scientific...

  7. Phase Coexistence of Complex Fluids in Shear Flow

    Olmsted, Peter D; Lu, C-Y David

    1999-01-01

    We present some results of recent calculations of rigid rod-like particles in shear flow, based on the Doi model. This is an ideal model system for exhibiting the generic behavior of shear-thinning fluids (polymer solutions, wormlike micelles, surfactant solutions, liquid crystals) in shear flow. We present calculations of phase coexistence under shear among weakly-aligned (paranematic) and strongly-aligned phases, including alignment in the shear plane and in the vorticity direction (log-rol...

  8. Coexistence of superconductivity, ferromagnetism and antiferromagnetism in iron pnictides

    Gill, Raminder

    2016-05-01

    Coexistence of Superconductivity and magnetism have always been the fascinating area of interest for condensed-matter physicists. A variety of systems, such as cuprates, heavy fermions, and iron pnictides showed superconductivity in a narrow region near the border to antiferromagnetism (AFM)as a function of pressure or doping. However, the coexistence of superconductivity and ferromagnetism (FM) has seen in URhGe, UGe2, ErRh4B4 and many compounds. Here, we present a third situation where superconductivity coexists with FM and AFM. The recent experimental finding of interplay of ferromagnetism,antiferromagnetism and superconductivity in EuFe2(As1-xPx)2 impressed us to discuss this problem in detail. Ironpnictides are high Tc magnetic superconductors and could be very useful in finding many new superconductorswith high Tc probably near to room temperature. In this paper, we have theoretically calculated the superconducting order parameter of EuFe2(As1-xPx)2 where magnetic ordering is due to Eu+ moments and superconductivity is due to Fe3+ moments. The Eu ions order antiferromagnetically for x≤0.13, while a crossover is observed for x≥0.22 whereupon the Eu ions order ferromagnetically.

  9. Education of Coexistence as Technē Tou Biou

    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. 

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

    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.

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

    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.

  12. Digital Ecology: Coexistence and Domination among Interacting Networks

    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.

  13. Deformed Structures and Shape Coexistence in Zr-98

    Olaizola, Bruno; 8pi Collaboration

    2015-10-01

    The nuclear structure of the zirconium isotopes evolves from a mid-open neutron shell deformed region (80Zr), through a closed shell (90Zr), to a closed subshell (96Zr), and then to a sudden reappearance of deformation (100Zr). This rapid onset of deformation across the Zr isotopes is unprecedented, and the issue of how collectivity appears and disappears in these isotopes is of special interest. Until recently, only 98Zr (and maybe 100Zr) had indirect and weak evidence for shape coexistence, with only speculative interpretation of the experiments. Recent results from high precision B(E2) measurements provided direct evidence of shape coexistence in 94Zr and suggested that it may happen in many other nuclei in this region. In order to provide direct evidence of shape coexistence in 98Zr a high-statistical-quality γγ experiment was carried out with the 8 π spectrometer at ISAC-TRIUMF. The array consists of 20 Compton-suppressed hyper-pure germanium detectors plus β particle and conversion electron detectors. Excited states up to ~ 5 MeV in 98Zr were populated in the β- decay of 98Y Jπ = (0-) and 98mY J = (4,5). Preliminary results on key branching ratios will be presented. This work was supported by the Natural Sciences and Engineering Research Council of Canada and the National Research Council of Canada.

  14. Solar and Stellar Photospheric Abundances

    Prieto, Carlos Allende

    2016-01-01

    The determination of photospheric abundances in late-type stars from spectroscopic observations is a well-established field, built on solid theoretical foundations. Improving those foundations to refine the accuracy of the inferred abundances has proven challenging, but progress has been made. In parallel, developments on instrumentation, chiefly regarding multi-object spectroscopy, have been spectacular, and a number of projects are collecting large numbers of observations for stars across the Milky Way and nearby galaxies, promising important advances in our understanding of galaxy formation and evolution. After providing a brief description of the basic physics and input data involved in the analysis of stellar spectra, a review is made of the analysis steps, and the available tools to cope with large observational efforts. The paper closes with a quick overview of relevant ongoing and planned spectroscopic surveys, and highlights of recent research on photospheric abundances.

  15. Solar and stellar photospheric abundances

    Allende Prieto, Carlos

    2016-07-01

    The determination of photospheric abundances in late-type stars from spectroscopic observations is a well-established field, built on solid theoretical foundations. Improving those foundations to refine the accuracy of the inferred abundances has proven challenging, but progress has been made. In parallel, developments on instrumentation, chiefly regarding multi-object spectroscopy, have been spectacular, and a number of projects are collecting large numbers of observations for stars across the Milky Way and nearby galaxies, promising important advances in our understanding of galaxy formation and evolution. After providing a brief description of the basic physics and input data involved in the analysis of stellar spectra, a review is made of the analysis steps, and the available tools to cope with large observational efforts. The paper closes with a quick overview of relevant ongoing and planned spectroscopic surveys, and highlights of recent research on photospheric abundances.

  16. The primordial helium abundance from updated emissivities

    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.

  17. Steelhead Abundance - Point Features [ds184

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

  18. Coho Abundance - Point Features [ds182

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

  19. Coho Abundance - Linear Features [ds183

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

  20. Chinook Abundance - Point Features [ds180

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

  1. Steelhead Abundance - Linear Features [ds185

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

  2. Hf Transition Probabilities and Abundances

    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...

  3. Gd Transition Probabilities and Abundances

    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...

  4. Abundance estimation and Conservation Biology

    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

  5. Discovery of the shape coexisting 0{sup +} state in {sup 32}Mg

    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

  6. Effect of hyperons on phase coexistence in strange matter

    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.

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

    Zafer Subasi

    2014-08-01

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

  8. Unexpected Coexisting Myocardial Infarction Detected by Delayed Enhancement MRI

    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.

  9. Coexisting Pulses in a Model for Binary-Mixture Convection

    Riecke, H; Riecke, Hermann; Rappel, Wouter-Jan

    1995-01-01

    We address the striking coexistence of localized waves (`pulses') of different lengths which was observed in recent experiments and full numerical simulations of binary-mixture convection. Using a set of extended Ginzburg-Landau equations, we show that this multiplicity finds a natural explanation in terms of the competition of two distinct, physical localization mechanisms; one arises from dispersion and the other from a concentration mode. This competition is absent in the standard Ginzburg-Landau equation. It may also be relevant in other waves coupled to a large-scale field.

  10. Co-existence of Bronchiectasis and Chronic Obstructive Pulmonary Disease.

    Goel, Nitin; Gupta, Pawan; Singh, Abhijeet; Prasad, Rajendra

    2015-01-01

    We present the case of a 56-year-old male who presented with cough and breathlessness. Chest radiograph (postero-anterior view) showed bulla and signs of hyperinflation in the right upper zone with cystic shadows in the left lower zone. Spirometry showed severe irreversible airflow obstruction with restriction and decreased diffusion capacity for carbon monoxide. On high resolution computed tomography (HRCT), right upper lobe bulla with emphysematous changes and left lower lobe cystic bronchiectasis were seen. Considering its rarity of occurrence and paucity of data in literature regarding co-existence of bronchiectasis with emphysema, this case is being reported. PMID:26591975

  11. Thermophysical properties of hydrogen along the liquid-vapor coexistence

    Osman, S. M.; Sulaiman, N.; Bahaa Khedr, M.

    2016-05-01

    We present Theoretical Calculations for the Liquid-Vapor Coexistence (LVC) curve of fluid Hydrogen within the first order perturbation theory with a suitable first order quantum correction to the free energy. In the present equation of state, we incorporate the dimerization of H2 molecule by treating the fluid as a hard convex body fluid. The thermophysical properties of fluid H2 along the LVC curve, including the pressure-temperature dependence, density-temperature asymmetry, volume expansivity, entropy and enthalpy, are calculated and compared with computer simulation and empirical results.

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

    Hartvig, Martin; Andersen, Ken Haste

    2013-01-01

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

  13. Metazoan promoters

    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 ...

  14. Sm Transition Probabilities and Abundances

    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. Abundances in stars with exoplanets

    Israelian, Garik

    2003-01-01

    Extensive spectroscopic studies of stars with and without planets have concluded that stars hosting planets are significantly more metal-rich than those without planets. More subtle trends of different chemical elements begin to appear as the number of detected extrasolar planetary systems continues to grow. I review our current knowledge concerning the observed abundance trends of various chemical elements in stars with exoplanets and their possible implications.

  16. Health Promotion

    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...

  17. Oxygen Gas Phase Abundance Revisited

    André, M K; Howk, J C; Ferlet, R; Désert, J M; Hébrard, G; Lacour, S; Lecavelier-des-Etangs, A; Vidal-Madjar, A; Moos, H W

    2003-01-01

    We present new measurements of the interstellar gas-phase oxygen abundance along the sight lines towards 19 early-type galactic stars at an average distance of 2.6 kpc. We derive O {\\small I} column densities from {\\it HST}/STIS observations of the weak 1355 \\AA intersystem transition. We derive total hydrogen column densities [N(H {\\small I})+2N(H$_2$)] using {\\it HST}/STIS observations of \\lya and {\\it FUSE} observations of molecular hydrogen. The molecular hydrogen content of these sight lines ranges from f(H$_2$) = 2N(H$_2$)/[N(H {\\small I})+2N(H$_2$)] = 0.03 to 0.47. The average $$ of 6.3$\\times10^{21}$ cm$^{-2}$ mag$^{-1}$ with a standard deviation of 15% is consistent with previous surveys. The mean oxygen abundance along these sight lines, which probe a wide range of galactic environments in the distant ISM, is 10$^6$ \\oh = $408 \\pm 13$ (1 $\\sigma$ in the mean). %$({\\rm O/H})_{gas} = 408 \\pm 14$(1 $\\sigma$). We see no evidence for decreasing gas-phase oxygen abundance with increasing molecular hydroge...

  18. Shape coexistence in the microscopically guided interacting boson model

    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...

  19. Water Resources Management. Coexistence and Conflict in Semiarid Brazil

    Thiago Ferreira Dias

    2016-01-01

    Full Text Available The paper analyzes water management in the Brazilian semiarid region with emphasis on aspects of coexistence and conflicts over access in rural areas. Experiences of social coexistence in semiarid technologies from the joint to the Brazilian semiarid (ASA and water conflicts from cases of irrigated areas in the states of Ceará and Rio Grande do Norte are explained. For this purpose, we used a qualitative approach through the use of primary and secondary data. The cases provide concrete actions that articulate civil society and the State in favor of the common good. The results indicate that the policy articulated by the ASA there is a governance process in which there are links between the forums of civil society and the interfaces in the planning and implementation of public policies in building public agenda that can bridge the gap between planning, deployment, management and improvement of this policy. In the second case the policy is implemented exclusion and allocation of those communities, placing them on the margins of development, scrapping its links with the territory. The water is not seen from the perspective of the common good and the communities are perceived as an obstacle to “development”. Finally, it outlines themselves from the cases under study, with the idea that limiting access to water in the semiarid region, reflects the precarious welfare and perpetuation of relations of dependency, paternalism and clientelism high proportion of the population rural Brazilian semiarid.

  20. Physical layer simulation study for the coexistence of WLAN standards

    This paper presents the results of a study on the performance of wireless local area network (WLAN) devices in the presence of interference from other wireless devices. To understand the coexistence of these wireless protocols, simplified physical-layer-system models were developed for the Bluetooth, Wireless Fidelity (WiFi), and Zigbee devices, all of which operate within the 2.4-GHz frequency band. The performances of these protocols were evaluated using Monte-Carlo simulations under various interference and channel conditions. The channel models considered were basic additive white Gaussian noise (AWGN), Rayleigh fading, and site-specific fading. The study also incorporated the basic modulation schemes, multiple access techniques, and channel allocations of the three protocols. This research is helping the U.S. Nuclear Regulatory Commission (NRC) understand the coexistence issues associated with deploying wireless devices and could prove useful in the development of a technical basis for guidance to address safety-related issues with the implementation of wireless systems in nuclear facilities. (authors)

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

    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.

  2. Physical layer simulation study for the coexistence of WLAN standards

    Howlader, M. K. [Marquette Univ., 222 Haggerty Hall, P. O. Box 1881, Milwaukee, WI 53201 (United States); Keiger, C. [Analysis and Measurement Services Corporation, 9111 Cross Park Drive, Knoxville, TN 37923 (United States); Ewing, P. D. [Oak Ridge National Laboratory, MS-6006, P. O. Box 2008, Oak Ridge, TN 37831 (United States); Govan, T. V. [U.S. Nuclear Regulatory Commission, MS T-10-D20, 11545 Rockville Pike, Rockville, MD 20852 (United States)

    2006-07-01

    This paper presents the results of a study on the performance of wireless local area network (WLAN) devices in the presence of interference from other wireless devices. To understand the coexistence of these wireless protocols, simplified physical-layer-system models were developed for the Bluetooth, Wireless Fidelity (WiFi), and Zigbee devices, all of which operate within the 2.4-GHz frequency band. The performances of these protocols were evaluated using Monte-Carlo simulations under various interference and channel conditions. The channel models considered were basic additive white Gaussian noise (AWGN), Rayleigh fading, and site-specific fading. The study also incorporated the basic modulation schemes, multiple access techniques, and channel allocations of the three protocols. This research is helping the U.S. Nuclear Regulatory Commission (NRC) understand the coexistence issues associated with deploying wireless devices and could prove useful in the development of a technical basis for guidance to address safety-related issues with the implementation of wireless systems in nuclear facilities. (authors)

  3. Coexistence of Interacting Opinions in a Generalized Sznajd Model

    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...

  4. Planetary nebulae abundances and stellar evolution

    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 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...

  5. Cognitive radio networks medium access control for coexistence of wireless systems

    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 ...

  6. Thin-thick coexistence behavior of 8CB liquid crystalline films on silicon.

    Garcia, R; Subashi, E; Fukuto, M

    2008-05-16

    The wetting behavior of thin films of 4-n-octyl-4'-cyanobiphenyl (8CB) on Si is investigated via optical and x-ray reflectivity measurement. An experimental phase diagram is obtained showing a broad thick-thin coexistence region spanning the bulk isotropic-to-nematic (T(IN)) and the nematic-to-smectic-A (T(NA)) temperatures. For Si surfaces with coverages between 47 and 72 +/- 3 nm, reentrant wetting behavior is observed twice as we increase the temperature, with separate coexistence behaviors near T(IN) and T(NA). For coverages less than 47 nm, however, the two coexistence behaviors merge into a single coexistence region. The observed thin-thick coexistence near the second-order NA transition is not anticipated by any previous theory or experiment. Nevertheless, the behavior of the thin and thick phases within the coexistence regions is consistent with this being an equilibrium phenomenon. PMID:18518487

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

    Plez, B.; Hill, V.; Cayrel, R.; Spite, M.; Barbuy, B.; Beers, T.C.; Bonifacio, P.; Primas, F.; Nordström, B.

    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...

  8. Coexisting chaotic attractors in a single neuron model with adapting feedback synapse

    Li Chunguang [Institute of Electronic Systems, School of Electronic Engineering, University of Electronic Science and Technology of China, Chengdu 610054 (China)]. E-mail: cgli@uestc.edu.cn; Chen Guanrong [Department of Electronic Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong (China)]. E-mail: gchen@ee.cityu.edu.hk

    2005-03-01

    In this paper, we consider the nonlinear dynamical behavior of a single neuron model with adapting feedback synapse, and show that chaotic behaviors exist in this model. In some parameter domain, we observe two coexisting chaotic attractors, switching from the coexisting chaotic attractors to a connected chaotic attractor, and then switching back to the two coexisting chaotic attractors. We confirm the chaoticity by simulations with phase plots, waveform plots, and power spectra.

  9. Relatedness among arbuscular mycorrhizal fungi drives plant growth and intraspecific fungal coexistence

    Roger, Aurélien; Colard, Alexandre; Angelard, Caroline; Sanders, Ian R.

    2013-01-01

    Arbuscular mycorrhizal fungi (AMF) form symbioses with most plant species. They are ecologically important determinants of plant growth and diversity. Considerable genetic variation occurs in AMF populations. Thus, plants are exposed to AMF of varying relatedness to each other. Very little is known about either the effects of coexisting AMF on plant growth or which factors influence intraspecific AMF coexistence within roots. No studies have addressed whether the genetics of coexisting AMF, a...

  10. Coexistence: Threat to the Performance of Heterogeneous Network

    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

  11. Dolomite abundance in Chinese loess deposits: A new proxy of monsoon precipitation intensity

    Meng, Xianqiang; Liu, Lianwen; Balsam, William; Li, Shilei; He, Tong; Chen, Jun; Ji, Junfeng

    2015-12-01

    Dolomite of detrital origin in carbonate-rich soil can help indicate the intensity of carbonate dissolution and leaching processes. Using Fourier transform infrared spectroscopy, we generated a high-resolution record of dolomite and calcite contents from eight sections on the Chinese Loess Plateau spanning the last 130 kyr. Based on the relative abundance of calcite and dolomite, four dissolution phases of carbonate minerals related to summer monsoon (SM) variations are identified as follows: (1) coexistence of dolomite and calcite indicating a very weak SM with a mean annual precipitation (MAP) leaching indicating a strong SM, 690 leaching of the underlying loess layer suggesting a very strong SM with MAP > 725 mm.

  12. The Collision and Coexistence between Chinese and American Cultures——The Collision and Coexistence between Two Generations in The Joy Luck Club

    Zhang yuan

    2009-01-01

    In many Chinese and American works, the differences of backgrounds, such as culture, customs and so on occupy a large part, through which readers can see the collision as well as coexistence between the two cultures. The Joy Luck Club has no exception. In this work, the commtmication under different cultural backgrounds between the generations generates a lot of collision, but they get coex-istence in the end. In this paper, the author will analyze the continuous collision and the final coexistence of the four pairs of mothers and daughters, so that readers can learn more about the differences between Chinese and American culture.

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

    Sekikawa, Munehisa; Inaba, Naohiko

    2016-01-01

    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.

  14. Relatedness among arbuscular mycorrhizal fungi drives plant growth and intraspecific fungal coexistence.

    Roger, Aurélien; Colard, Alexandre; Angelard, Caroline; Sanders, Ian R

    2013-11-01

    Arbuscular mycorrhizal fungi (AMF) form symbioses with most plant species. They are ecologically important determinants of plant growth and diversity. Considerable genetic variation occurs in AMF populations. Thus, plants are exposed to AMF of varying relatedness to each other. Very little is known about either the effects of coexisting AMF on plant growth or which factors influence intraspecific AMF coexistence within roots. No studies have addressed whether the genetics of coexisting AMF, and more specifically their relatedness, influences plant growth and AMF coexistence. Relatedness is expected to influence coexistence between individuals, and it has been suggested that decreasing ability of symbionts to coexist can have negative effects on the growth of the host. We tested the effect of a gradient of AMF genetic relatedness on the growth of two plant species. Increasing relatedness between AMFs lead to markedly greater plant growth (27% biomass increase with closely related compared to distantly related AMF). In one plant species, closely related AMF coexisted in fairly equal proportions but decreasing relatedness lead to a very strong disequilibrium between AMF in roots, indicating much stronger competition. Given the strength of the effects with such a shallow relatedness gradient and the fact that in the field plants are exposed to a steeper gradient, we consider that AMF relatedness can have a strong role in plant growth and the ability of AMF to coexist. We conclude that AMF relatedness is a driver of plant growth and that relatedness is also a strong driver of intraspecific coexistence of these ecologically important symbionts. PMID:23823490

  15. ANALYSIS OF WIFI AND WIMAX AND WIRELESS NETWORK COEXISTENCE

    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.

  16. Coexistence of metallic and insulating-like states in graphene.

    Wu, Fang; Huang, Jing; Li, Qunxiang; Deng, Kaiming; Kan, Erjun

    2015-01-01

    Since graphene has been taken as the potential host material for next-generation electric devices, coexistence of high carrier mobility and an energy gap has the determining role in its real applications. However, in conventional methods of band-gap engineering, the energy gap and carrier mobility in graphene are seemed to be the two terminals of a seesaw, which limit its rapid development in electronic devices. Here we demonstrated the realization of insulating-like state in graphene without breaking Dirac cone. Using first-principles calculations, we found that ferroelectric substrate not only well reserves the Dirac fermions, but also induces pseudo-gap states in graphene. Calculated transport results clearly revealed that electrons cannot move along the ferroelectric direction. Thus, our work established a new concept of opening an energy gap in graphene without reducing the high mobility of carriers, which is a step towards manufacturing graphene-based devices. PMID:25754862

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

    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. PMID:3308993

  18. Coexistence of carcinoma and tuberculosis in one breast

    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.

  19. Coexistence of negative photoconductivity and hysteresis in semiconducting graphene

    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.

  20. Coexistence of metallic and insulating-like states in graphene

    Wu, Fang; Huang, Jing; Li, Qunxiang; Deng, Kaiming; Kan, Erjun

    2015-03-01

    Since graphene has been taken as the potential host material for next-generation electric devices, coexistence of high carrier mobility and an energy gap has the determining role in its real applications. However, in conventional methods of band-gap engineering, the energy gap and carrier mobility in graphene are seemed to be the two terminals of a seesaw, which limit its rapid development in electronic devices. Here we demonstrated the realization of insulating-like state in graphene without breaking Dirac cone. Using first-principles calculations, we found that ferroelectric substrate not only well reserves the Dirac fermions, but also induces pseudo-gap states in graphene. Calculated transport results clearly revealed that electrons cannot move along the ferroelectric direction. Thus, our work established a new concept of opening an energy gap in graphene without reducing the high mobility of carriers, which is a step towards manufacturing graphene-based devices.

  1. The Coexistence of Coeliac Disease, Psoriasis and Vitiligo

    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.

  2. Disappearance of neutron magic numbers and deformation coexistence

    The disappearance of N=8, 20 and 28 magic numbers in the neutron excess nuclei is a representative example of the special features of the unstable nuclei. In this lecture of summer school, the problems of the magic number disappearance are presented. And the appearance of the deformation coexistence and the anomalous cluster structure come into the problem with them. At the begging the Antisymmetrized Molecular Dynamic (AMD) framework is explained with finite range two body central force and Gorgny DIS force composed of the zero range spin-orbit force and saturability. Island of inversion is explained in the nuclear chart shown in the figure and energy curves of the nuclei near 32Mg and the excitation level schemes of 32Mg are shown in the serial figures. As one of the extreme example of the nuclear structure the deformation of 19F is picked up. The level schemes and structures of 21F are shown as well. The molecule-like structure in the island of inversion is clear. The rotational band energy of fluorine isotopes are shown up to 29F. As a new deformation area, disappearance of N=28 magic number is in the spotlight recently. In this case it is characteristic properties that the parities of the orbits to form the gap must be the same but the angular momenta should be different by 2. According to the AMD research, it is shown that deformations of prolate, three-axis asymmetric and oblate characters coexist in the very low excitation energy region accompanying the disappearance of N=28 gap. The concept of magic numbers has been very fundamental in nuclear physics since the success of shell model. At present its disappearance in the unstable nuclei is one of the most challenging problems in the understanding of the nuclear many body problems. (S. Funahashi)

  3. A note on the abundance conjecture

    Dorsch, Tobias; Lazić, Vladimir

    2014-01-01

    We prove that the abundance conjecture for non-uniruled klt pairs in dimension $n$ implies the abundance conjecture for uniruled klt pairs in dimension $n$, assuming the Minimal Model Program in lower dimensions.

  4. Solar System chemical abundances corrected for systematics

    Gonzalez, Guillermo

    2014-01-01

    The relative chemical abundances between CI meteorites and the solar photosphere exhibit a significant trend with condensation temperature. A trend with condensation temperature is also seen when the solar photospheric abundances are compared to those of nearby solar twins. We use both these trends to determine the alteration of the elemental abundances of the meteorties and the photosphere by fractionation and calculate a new set of primordial Solar System abundances.

  5. Promoting Models

    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.

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

    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.

  7. Experimental evidence rejects pairwise modelling approach to coexistence in plant communities

    Dormann, Carsten F.; Roxburgh, Stephen H.

    2005-01-01

    Competition is often invoked as the cause of plant species loss with increasing system productivity. Experimental results for multispecies assemblages are virtually absent and mathematical models are thus used to explore the relationship between competition and coexistence. Modelling approaches to coexistence and diversity in competitive communities commonly employ Lotka–Volterra-type (LV) models with additive pairwise competitive effects.

  8. The principle(s) of co-existence in Europe: Social, economic and legal avenues

    Purnhagen, K.; Wesseler, J.H.H.

    2015-01-01

    The European policy of coexistence follows a number of well-established social, economic and legal principles. Applying these principles in practice has resulted in a complex “rag rug” of coexistence policies in Europe. This rag rug makes enforcement of these principles difficult, at times even impo

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

    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...

  10. Coexistence of hypothyroidism with inflammatory arthritis is associated with cardiovascular disease in women.

    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

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

    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

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

    Michael G Mazzacavallo

    Full Text Available 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.

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

    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. PMID:26633177

  14. Surface abundances of ON stars

    Martins, F.; Simón-Díaz, S.; Palacios, A.; Howarth, I.; Georgy, C.; Walborn, N. R.; Bouret, J.-C.; Barbá, R.

    2015-06-01

    Context. Massive stars burn hydrogen through the CNO cycle during most of their evolution. When mixing is efficient or when mass transfer in binary systems occurs, chemically processed material is observed at the surface of O and B stars. Aims: ON stars show stronger lines of nitrogen than morphologically normal counterparts. Whether this corresponds to the presence of material processed through the CNO cycle is not known. Our goal is to answer this question. Methods: We performed a spectroscopic analysis of a sample of ON stars with atmosphere models. We determined the fundamental parameters as well as the He, C, N, and O surface abundances. We also measured the projected rotational velocities. We compared the properties of the ON stars to those of normal O stars. Results: We show that ON stars are usually rich in helium. 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 cannot account for the extreme enrichment observed among ON main sequence stars. Some ON stars are members of binary systems, but others are single stars as indicated by stable radial velocities. Mass transfer is therefore not a simple explanation for the observed chemical properties. Conclusions: We conclude that ON stars show extreme chemical enrichment at their surface, consistent with nucleosynthesis through the CNO cycle. Its origin is not clear at present. Based on observations obtained 1) at the Anglo-Australian Telescope; 2) at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Science de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii; 3) at the ESO/La Silla Observatory under programs 081.D-2008, 083.D-0589, 086.D-0997; 4) the Nordic Optical Telescope, operated on the island of La

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

    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.

  16. Defence and Security Research Coexistence, Coherence, and Convergence

    Breant, Christian; Karock, Ulrich

    Defence and security research have coexisted at the European Union level since the inception of the European Defence Agency (EDA). The agency was established under a Joint Action of the Council of Ministers on 12 July 2004, "to support the Member States and the Council in their effort to improve European defence capabilities in the field of crisis management and to sustain the European Security and Defence Policy as it stands now and develops in the future".1 The political decision to create the EDA was taken at the Thessaloniki European Council on 19 and 20 June 2003. Heads of State or Government tasked the Council bodies to undertake the requisite actions, in the course of 2004, to create an intergovernmental agency in the field of defence capabilities development, research, acquisition and armaments. The EDA has been located in Brussels right from the start. It is an intergovernmental EU agency under the Council's authority within the single institutional framework of the Union. It performs its mission in close cooperation with its participating Member States (pMS) and the European institutional actors.

  17. Spatial–Numerical and Ordinal Positional Associations Coexist in Parallel

    Huber, Stefan; Klein, Elise; Moeller, Korbinian; Willmes, Klaus

    2016-01-01

    There is evidence for a systematic association of numbers and space. A prominent finding supporting this notion is the spatial-numerical association of response codes (SNARC) effect describing relatively faster responses to smaller numbers using a left-hand key and to larger numbers using a right-hand key. However, the assumption of the SNARC effect reflecting spatial-numerical associations was challenged recently. A working memory account was proposed suggesting that not numbers per se but their position in a memorized sequence is associated with space. Yet, there is also first evidence suggesting that this ordinal position and the SNARC effect may not be mutually exclusive. In the present study, we further examined the relationship between the ordinal position and the SNARC effect. We manipulated the number of items in the memorized ordered sequence and the number range employed. Results revealed both a significant ordinal position effect, but also a significant SNARC effect, substantiating the view that both effects are not mutually exclusive but may co-exist. Furthermore, we found that the SNARC effect was reduced when numbers ranging from 1 to 10 versus numbers ranging from 1 to 9 were employed. Thus, our results question a pure working memory account for the SNARC effect. Additionally, they highlight the critical role of the number range employed in research about the SNARC effect. PMID:27064216

  18. Probabilistic Coexistence and Throughput of Cognitive Dual-Polarized Networks

    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.

  19. China and the Global Uranium Market: Prospects for Peaceful Coexistence

    Pascale Massot

    2013-01-01

    Full Text Available 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. China and the global uranium market: prospects for peaceful coexistence.

    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. PMID:23606818

  1. [Ecomorphological explanations of passerines coexistence in alpine meadow].

    Liu, Li-Hua; Chen, Xiao-Cheng; Chu, Hui; Sun, Jia-Chen; Zhang, Xiao-Ai; Zhao, Liang

    2013-06-01

    Species ecomorphological characteristics are the evolutionary results of selective pressures that have enabled individuals of a given species to survive and reproduce. Closely related species co-occurring in homogeneous environments should be morphologically distinct to partition limited resources, so as to minimize interspecific competition. From 1983 to 2012, we studied the ecomorphological characteristics of nine passerine species in alpine meadow. Results showed six ecomorphological characteristics of the nine species were significantly different. Approximately, 92.0% of samples were correctly classified and the correct rates ranged from 84.5% to 100.0%, except for the Oriental Skylark (Eremophila alpestris), which was 79.2%. Accordingly, the nine species were divided into five guilds based on their characteristics. Results indicated that the niches of all species were divergent, and the ecomorphological characteristics of the specific species in each guild were related to their habitats and foraging behaviors. These results also explained the possible mechanisms of different species coexistence in alpine meadow. PMID:23775990

  2. Phase coexistence of clusters and islands: europium on graphene

    The adsorption and equilibrium surface phases of europium (Eu) on graphene on Ir(111) are investigated in the temperature range from 35 to 400 K and for coverages ranging from a small fraction of a saturated monolayer to the second layer by scanning tunnelling microscopy. Using density functional theory including 4f-shell Coulomb interactions and modelling of electronic interactions, excellent agreement with the experimental results for the equilibrium adsorbate phase, adsorbate diffusion and work function is obtained. Most remarkably, at 300 K in an intermediate coverage range a phase of uniformly distributed Eu clusters (size 10-20 atoms) coexists in two-dimensional equilibrium with large Eu-islands in a (√3×√3)R30o structure. We argue that the formation of the cluster phase is driven by the interplay of three effects. Firstly, the metallic Eu-Eu binding leads to the local stability of (√3×√3)R30o structures. Secondly, electrons lower their kinetic energy by leaving the Eu clusters, thereby doping graphene. Thirdly, the Coulomb energy penalty associated with the charge transfer from Eu to graphene is strongly reduced for smaller clusters. (paper)

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

    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.

  4. Origin of Cosmic Chemical Abundances

    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/...

  5. Significant biases affecting abundance determinations

    Wesson, Roger

    2015-08-01

    I have developed two highly efficient codes to automate analyses of emission line nebulae. The tools place particular emphasis on the propagation of uncertainties. The first tool, ALFA, uses a genetic algorithm to rapidly optimise the parameters of gaussian fits to line profiles. It can fit emission line spectra of arbitrary resolution, wavelength range and depth, with no user input at all. It is well suited to highly multiplexed spectroscopy such as that now being carried out with instruments such as MUSE at the VLT. The second tool, NEAT, carries out a full analysis of emission line fluxes, robustly propagating uncertainties using a Monte Carlo technique.Using these tools, I have found that considerable biases can be introduced into abundance determinations if the uncertainty distribution of emission lines is not well characterised. For weak lines, normally distributed uncertainties are generally assumed, though it is incorrect to do so, and significant biases can result. I discuss observational evidence of these biases. The two new codes contain routines to correctly characterise the probability distributions, giving more reliable results in analyses of emission line nebulae.

  6. Surface Expression of Precursor N-cadherin Promotes Tumor Cell Invasion

    Deborah Maret

    2010-12-01

    Full Text Available The expression of N-cadherin (NCAD has been shown to correlate with increased tumor cell motility and metastasis. However, NCAD-mediated adhesion is a robust phenomenon and therefore seems to be inconsistent with the “release” from intercellular adhesion required for invasion. We show that in the most invasive melanoma and brain tumor cells, altered posttranslational processing results in abundant nonadhesive precursor N-cadherin (proNCAD at the cell surface, although total NCAD levels remain constant. We demonstrate that aberrantly processed proNCAD promotes cell migration and invasion in vitro. Furthermore, in human tumor specimens, we find high levels of proNCAD as well, supporting an overall conclusion that proNCAD and mature NCAD coexist on these tumor cell surfaces and that it is the ratio between these functionally antagonistic moieties that directly correlates with invasion potential. Our work provides insight into what may be a widespread mechanism for invasion and metastasis and challenges the current dogma of the functional roles played by classic cadherins in tumor progression.

  7. A integração regional e a coexistência entre ALCA, MERCOSUL e comunidade andina

    Sergio Eduardo Canella

    2004-01-01

    The objective in this work is to verify the possibility of coexistence between the FTAA, MERCOSUL and Andean Community.O objetivo neste trabalho é verificar a possibilidade de coexistência entre a ALCA, MERCOSUL e Comunidade Andina.

  8. Hydrocarbon Reserves: Abundance or Scarcity

    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 impact on the growth

  9. Hydrocarbon Reserves: Abundance or Scarcity

    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

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

    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...

  11. The Sulfur Abundance Anomaly in Planetary Nebulae

    Henry, R B C; Kwitter, K B; Milingo, M B

    2006-01-01

    The failure of S and O abundances in most planetary nebulae to display the same strong direct correlation that is observed in extragalactic H II regions represents one of the most perplexing problems in the area of PN abundances today. Galactic chemical evolution models as well as large amounts of observational evidence from H II region studies support the contention that cosmic abundances of alpha elements such as O, Ne, S, Cl, and Ar increase together in lockstep. Yet abundance results from the Henry, Kwitter, & Balick (2004) database show a strong tendency for most PNe to have S abundances that are significantly less than expected from the observed level of O. One reasonable hypothesis for the sulfur anomaly is the past failure to properly measure the abundances of unseen ionization stages above S^+2. Future observations with Spitzer will allow us to test this hypothesis.

  12. Oxygen abundances in nearby dwarf irregular galaxies

    Oxygen abundances are obtained by optical spectrophotometry of H II regions in seven nearby dwarf irregular galaxies. All of these yield oxygen abundances of less than 1/10 of the solar value, and most are in the range of 3-5 percent of the solar value. This suggests that observations of nearby dwarf galaxies may provide an effective means for studying the chemical evolution of low-mass galaxies and, possibly, the primordial helium abundance. A strong correlation is found between the oxygen abundances and absolute magnitudes for nearby irregular galaxies. This correlation will be useful for estimating abundances of irregular galaxies without observable H II regions, and possibly as a distance indicator for irregular galaxies with known abundances. It is inferred from this relationship that infall is no more important in irregular galaxies with extremely large H I halos than in typical irregular galaxies. 72 refs

  13. Stellar abundances of beryllium and CUBES

    Smiljanic, R

    2014-01-01

    Stellar abundances of beryllium are useful in different areas of astrophysics, including studies of the Galactic chemical evolution, of stellar evolution, and of the formation of globular clusters. Determining Be abundances in stars is, however, a challenging endeavor. The two Be II resonance lines useful for abundance analyses are in the near UV, a region strongly affected by atmospheric extinction. CUBES is a new spectrograph planned for the VLT that will be more sensitive than current instruments in the near UV spectral region. It will allow the observation of fainter stars, expanding the number of targets where Be abundances can be determined. Here, a brief review of stellar abundances of Be is presented together with a discussion of science cases for CUBES. In particular, preliminary simulations of CUBES spectra are presented, highlighting its possible impact in investigations of Be abundances of extremely metal-poor stars and of stars in globular clusters.

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

    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.

  15. Osteoarthritis of the hip or knee: which coexisting disorders are disabling?

    Reeuwijk, Kerstin G; de Rooij, Mariëtte; van Dijk, Gabriella M; Veenhof, Cindy; Steultjens, Martijn P; Dekker, Joost

    2010-07-01

    Exercise therapy is generally recommended in osteoarthritis (OA) of the hip or knee. However, coexisting disorders may bring additional impairments, which may necessitate adaptations to exercise for OA of the hip or knee. For the purpose of developing an adapted protocol for exercise therapy in OA patients with coexisting disorders, information is needed on which specific coexisting disorders in OA are associated with activity limitations and pain. To describe the relationship between specific coexisting disorders, activity limitations, and pain in patients with OA of the hip or knee, a cross-sectional cohort study among 288 older adults (50-85 years of age) with OA of hip or knee was conducted. Subjects were recruited from three rehabilitation centers and two hospitals. Demographic data, clinical data, information about coexisting disorders (i.e., comorbidity and other disorders), activity limitations (WOMAC: physical functioning domain), and pain (visual analogue scale (VAS)) were collected by questionnaire. Statistical analysis included descriptive statistics and multivariate regression analysis. Coexisting disorders associated with activity limitations were chronic back pain or hernia, arthritis of the hand or feet, and other chronic rheumatic diseases (all musculoskeletal disorders); diabetes and chronic cystitis (non-musculoskeletal disorders); hearing impairments in a face-to-face conversation, vision impairments in long distances, and dizziness in combination with falling (all sensory impairments); and overweight and obesity. Coexistent disorders associated with pain were arthritis of the hand or feet, other chronic rheumatic diseases (musculoskeletal disorders), and diabetes (non-musculoskeletal disorder). Specific disorders coexisting next to OA and associated with additional activity limitations and pain were identified. These coexisting disorders need to be addressed in exercise therapy and rehabilitation for patients with OA of the hip or knee. PMID

  16. Climate and local abundance in freshwater fishes

    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...

  17. Monitoring Butterfly Abundance: Beyond Pollard Walks

    Pellet, Jérôme; Bried, Jason T.; Parietti, David; Gander, Antoine; Heer, Patrick O.; Cherix, Daniel; Arlettaz, Raphaël

    2012-01-01

    Most butterfly monitoring protocols rely on counts along transects (Pollard walks) to generate species abundance indices and track population trends. It is still too often ignored that a population count results from two processes: the biological process (true abundance) and the statistical process (our ability to properly quantify abundance). Because individual detectability tends to vary in space (e.g., among sites) and time (e.g., among years), it remains unclear whether index counts truly...

  18. Analysis of Coexisting GPON and NG-PON1 (10G-PON Systems

    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.

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

    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.

  20. Promoting industrialisation

    When the first nuclear power programme is decided upon, automatically the country has to initiate in parallel a programme to modify or add to its current industrial structure and resources. The extent of this new industrialisation depends upon many factors which both, the Government and the Industries have to consider. The Government has a vital role which includes the setting up of the background against which the industrial promotion should take place and in many cases may have also to play an active role all along this programme. Equally, the existing industries have an important role so as to achieve the most efficient participation in the nuclear programme. Invariably the industrial promotional programme will incur a certain degree of transfer of technology, the extent depending on the policies adopted. For this technology transfer to take place efficiently, both the donor and the receiver have to recognise each other's legitimate ambitions and fears. The transfer of technology is a process having a high human content and both donor and receiver have to take this into account. This can be further complicated when there is a difference in culture between them. Technology transfer is carried out within a contractual and organisational framework which will identify the donor (licensor) and the receiver (licensee). This framework may take various forms from a simple cooperative agreement, through a joint-venture organisation right to a standard contract between two separate entities. Each arrangement has its advantages and drawbacks and requires investment of different degrees. One of the keys to a successful industrial promotion is having it carried out in a timely fashion which will be parallel with the nuclear power programme. Experience in some countries has shown the problems when the industrialisation is out of phase with the programme whilst in other cases this industrialisation was at a level and scale unjustified. (author)

  1. Xe isotopic abundances in enstatite meteorites and relations to other planetary reservoirs

    This paper describes the interpretation of xenon that was measured in the Abee meteorite. Reported Xe isotopic abundances in enstatite chondrites (EC's) show some variability, and this makes comparisons to other solar system reservoirs rather difficult. In contrast, we find uniform Xe isotopic abundances in the EC chondrite Abee for a variety of clasts, except for 128Xe and 129Xe, the isotopes affected by neutron capture in I and by extinct 129I. We report averages for the studied clasts which are consistent within error limits with OC-Xe and with the Q-Xe signature. On the other hand, the elemental abundance ratios Ar/Xe are variable between clasts. A strongly reducing environment which is indicated for enstatite meteorites was generally assumed to be consistent with conditions existing in the early inner solar system. Xe isotopic abundances in SNC meteorites from Mars and also those in some terrestrial wells show that distinct isotopic reservoirs coexisted on the same planets. In particular, the Xe isotopic signatures in terrestrial well gases show the presence of a minor distinct component in two of the reported four well gases. These authors suggested that the extra component represents solar Xe, but we show that also a meteoritic xenon reservoir of the Abee-Xe structure is an option. The reported Xe data in Ar-rich (subsolar) EC's show isotopic abundances slightly lighter than those in Abee-Xe, but the relative abundances of Ar, Kr, and Xe indicate only a minor component of elementally unfractionated solar Xe. The elemental ratios suggest rather a different origin for these gases: the loading of solar particles into grain surfaces during exposure at elevated temperatures during accretion of matter in the inner solar system. A model of this type was suggested for the accretion of gases now observed in the atmosphere on Venus. We note that disks of crystalline silicates (including enstatite and olivine) have been observed in T Tauri stars during their early

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

    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. Interplay of Coexisting Odd-Order Wave Mixings in a Five-Level Atomic System

    SONG Yue; HUO Shu-Li; LI Pei-Ying; SANG Su-Ling; WANG Zhi-Guo; ZHANG Yan-Peng

    2011-01-01

    @@ We experimentally investigate the interplay between two coexisting six-wave mixing (SWM) signals and the interference between coexisting four-wave mixing (FWM) and SWM signals in a five-level atomic system of85 Rb.When two electromagnetically induced transparency windows gradually overlap in frequency, the competition between these two SWM signals arises.Moreover, we report the experimental result which shows that the temporal interference with femtosecond time scales between FWM and SWM signals.%We experimentally investigate the interplay between two coexisting six-wave mixing (SWM) signals and the interference between coexisting four-wave mixing (FWM) and SWM signals in a five-level atomic system of 85 Rb.When two electromagnetically induced transparency windows gradually overlap in frequency, the competition between these two SWM signals arises.Moreover, we report the experimental result which shows that the temporal interference with femtosecond time scales between FWM and SWM signals.

  4. Osteomalacia and coxa vara. An unusual co-existence for femoral neck stress fracture

    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.

  5. Theoretical study on phase coexistence in ferroelectric solid solutions near the tricritical point

    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(Zr1−xTix)O3 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

  6. Theoretical study on phase coexistence in ferroelectric solid solutions near the tricritical point

    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.

  7. Do burdens of underweight and overweight coexist among lower socioeconomic groups in India?1234

    Subramanian, SV; Perkins, Jessica M; Khan, Kashif T.

    2009-01-01

    Background: The coexistence of underweight and overweight in rapidly developing economies is well recognized. However, less is known about the socioeconomic patterning of underweight and overweight as economies move through the epidemiologic transition.

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

    Rutherford, Alex; Harmon, Dion; Werfel, Justin; Gard-Murray, Alexander S.; Bar-Yam, Shlomiya; Gros, Andreas; Xulvi-Brunet, Ramon; Bar-Yam, Yaneer

    2014-01-01

    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. H...

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

    Rutherford, Alex; Harmon, Dion; 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. H...

  10. Coexistence or contradiction? GM crops versus alternative agricultures in Europe

    Levidow, Les; Boschert, Karin

    2008-01-01

    Agricultural biotechnology (agbiotech) has intersected with a wider debate about 'sustainable agriculture', especially in Europe. Agbiotech was initially promoted as an alternative which would avoid or remedy past problems of intensive agriculture, but such claims were soon challenged. Agbiotech has extended the dominant agri-industrial paradigm, while critics have counterposed alternatives corresponding to an agrarian-based rural development paradigm. Amid controversy over environmental a...

  11. Climate and local abundance in freshwater fishes.

    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. PMID:27429769

  12. Taking species abundance distributions beyond individuals

    Morlon, Helene; White, Ethan P.; Etienne, Rampal S.; Green, Jessica L.; Ostling, Annette; Alonso, David; Enquist, Brian J.; He, Fangliang; Hurlbert, Allen; Magurran, Anne E.; Maurer, Brian A.; McGill, Brian J.; Olff, Han; Storch, David; Zillio, Tommaso; Chave, Jérôme

    2009-01-01

    The species abundance distribution (SAD) is one of the few universal patterns in ecology. Research on this fundamental distribution has primarily focused on the study of numerical counts, irrespective of the traits of individuals. Here we show that considering a set of Generalized Species Abundance

  13. Methanol abundance in low mass protostars

    Maret, S

    2004-01-01

    Methanol lines observations of a sample of low mass Class 0 protostars are presented. Using a 1D radiative transfer model, I show that several protostars have large abundance jumps in the inner hot and dense region of envelopes, probably because of thermal grain mantle evaporation. These abundances are compared with a grain surface chemistry model.

  14. Testing for effects of climate change on competitive relationships and coexistence between two bird species

    Stenseth, Nils Chr.; Durant, Joël M.; Fowler, Mike S.; Matthysen, Erik; Adriaensen, Frank; Jonzén, Niclas; Chan, Kung-Sik; Liu, Hai; De Laet, Jenny; SHELDON, BEN C.; Visser, Marcel E; André A Dhondt

    2015-01-01

    Climate change is expected to have profound ecological effects, yet shifts in competitive abilities among species are rarely studied in this context. Blue tits (Cyanistes caeruleus) and great tits (Parus major) compete for food and roosting sites, yet coexist across much of their range. Climate change might thus change the competitive relationships and coexistence between these two species. Analysing four of the highest-quality, long-term datasets available on these species across Europe, we ...

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

    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.

  16. Local Distribution and coexistence of prevalent tree species in peat swamp forests of Central Kalimantan

    Herwint Simbolon

    2009-01-01

    SIMBOLON, H. 2009. Local Distribution and coexistence of prevalent tree species in peat swamp forests of Central Kalimantan. Reinwardtia 12(5): 373–382. ⎯ A study on the distribution and coexistence of prevalent tree species in peat swamp forests was conducted at Lahei and Kelampangan, Central Kalimantan. The prevalent species in both sites were Calophyllum canum, Combretocarpus rotundatus, Cratoxylum glaucum, Ctenolophon parvifolius, Elaeocarpus petiolatus, with Palaquium cochleariifolium at...

  17. Co-existence of classical and alternative activation programs in macrophages responding to Toxoplasma gondii

    Patil, Veerupaxagouda; Zhao, Yanlin; Shah, Suhagi; Fox, Barbara A.; Rommereim, Leah M.; Bzik, David J.; Yap, George S.

    2013-01-01

    Pro-inflammatory M1 macrophages are critical for defense against intracellular pathogens while alternatively-activated M2 macrophages mediate tissue homeostasis and repair. Whether these distinct activation programs are mutually exclusive or can co-exist within the same cell is unclear. Here, we report the co-existence of these programs in Toxoplasma gondii-elicited inflammatory macrophages. This is independent of parasite expression of the virulence factor ROP16 and host cell expression of s...

  18. The Coexistence of Competition and Cooperation between Networks: Implications from Two Taiwanese Healthcare Networks

    Peng, T A; Bourne, Mike

    2009-01-01

    The issue of coopetition, the coexistence of cooperation and competition, has recently come to the fore in the strategic management field. Previous coopetition research has focused on the intra-organizational level, inter- organizational level and triad level, but less attention has been paid to coopetition at the network level. The purpose of this paper is to address the coexistence of competition and cooperation between networks, and to depict how networks with different s...

  19. Coexistence of graph-oriented and relational data file organisations in a data bank system

    It is shown that a coexistence of hierarchical and relational data bank structures in computer networks in a common data bank system is possible. This coexistence model, first established by NIJSSEN, regards the graph theory CODASYL approach and CODD's relational model as graph-oriented, or rather table-oriented, data file organisation as presented to the user of a common logical structure of the data bank. (WB)

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

    Yamase, Hiroyuki; Eberlein, Andreas; Metzner, Walter

    2016-03-01

    We analyze the competition of magnetism and superconductivity in the two-dimensional Hubbard model with a moderate interaction strength, including the possibility of incommensurate spiral magnetic order. Using an unbiased renormalization group approach, we compute magnetic and superconducting order parameters in the ground state. In addition to previously established regions of Néel order coexisting with d-wave superconductivity, the calculations reveal further coexistence regions where superconductivity is accompanied by incommensurate magnetic order. PMID:26991188

  1. Coexistence of incommensurate magnetism and superconductivity in the two-dimensional Hubbard model

    Yamase, Hiroyuki; Eberlein, Andreas; Metzner, Walter

    2015-01-01

    We analyze the competition of magnetism and superconductivity in the two-dimensional Hubbard model with a moderate interaction strength, including the possibility of incommensurate spiral magnetic order. Using an unbiased renormalization group approach, we compute magnetic and superconducting order parameters in the ground state. In addition to previously established regions of Neel order coexisting with d-wave superconductivity, the calculations reveal further coexistence regions where super...

  2. A Prediction Algorithm for Coexistence Problem in Multiple-WBAN Environment

    2015-01-01

    The coexistence problem occurs when a single wireless body area network (WBAN) is located within a multiple-WBAN environment. This causes WBANs to suffer from severe channel interference that degrades the communication performance of each WBAN. Since a WBAN handles vital signs that affect human life, the detection or prediction of coexistence condition is needed to guarantee reliable communication for each sensor node of a WBAN. Therefore, this paper presents a learning-based algorithm to eff...

  3. Coexistence and Interference Mitigation for Wireless Body Area Networks: Improvements using On-Body Opportunistic Relaying

    Dong, Jie; SMITH, DAVID

    2013-01-01

    Coexistence, and hence interference mitigation, across multiple wireless body area networks (WBANs) is an important problem as WBANs become more pervasive. Here, two-hop relay-assisted cooperative communications using opportunistic relaying (OR) is proposed for enhancement of coexistence for WBANs. Suitable time division multiple access (TDMA) schemes are employed for both intra-WBAN and inter-WBANs access protocols. To emulate actual conditions of WBAN use, extensive on-body and inter-body "...

  4. Charged Particles on Surfaces: Coexistence of Dilute Phases and Periodic Structures on Membranes

    Sharon M Loverde; Solis, Francisco; de la Cruz, Monica Olvera

    2006-01-01

    We consider a mixture of one neutral and two oppositely charged types of molecules confined to a surface. Using analytical techniques and molecular dynamics simulations, we construct the phase diagram of the system and exhibit the coexistence between a patterned solid phase and a charge-dilute phase. The patterns in the solid phase arise from competition between short-range immiscibility and long-range electrostatic attractions between the charged species. The coexistence between phases leads...

  5. Co-existence of Sarcina Organisms and Helicobacter pylori Gastritis/Duodenitis in Pediatric Siblings

    Sauter, Jennifer L.; Nayar, Suresh K.; Anders, Paige D.; D’Amico, Michael; Butnor, Kelly J.; Wilcox, Rebecca L.

    2013-01-01

    Sarcina are gram-positive anaerobic bacteria found to be associated with delayed gastric emptying and gastric outlet obstruction. We describe two cases of Sarcina co-existing with Helicobacter pylori organisms in pediatric siblings presenting within four months of each other with pyloric obstruction secondary to severe gastritis/duodenitis. The co-existence of Sarcina and Helicobacter pylori has not, to our knowledge, been previously reported. Its characteristic tetrad packeted morphology per...

  6. Carvedilol, Bisoprolol, and Metoprolol Use in Patients With Coexistent Heart Failure and Chronic Obstructive Pulmonary Disease

    Su, Vincent Yi-Fong; Chang, Yu-Sheng; Hu, Yu-Wen; Hung, Man-Hsin; Ou, Shuo-Ming; Lee, Fa-Yauh; Chou, Kun-Ta; Yang, Kuang-Yao; Perng, Diahn-Warng; Chen, Tzeng-Ji; Liu, Chia-Jen

    2016-01-01

    Abstract Beta (β)-blockers are under-prescribed in patients with heart failure (HF) and concurrent chronic obstructive pulmonary disease (COPD) due to concerns about adverse pulmonary effects and a poor understanding of the effects of these drugs. We aimed to evaluate the survival effects of β-blockers in patients with coexistent HF and COPD. Using the Taiwan National Health Insurance Research Database, we conducted a nationwide population-based study. Patients with coexistent HF and COPD dia...

  7. Spatial Dimension of Externalities and the Coase Theorem : Implications for Co-existence of Transgenic Crops

    Beckmann, V.; Wesseler, J.H.H.

    2005-01-01

    "No form of agriculture should be excluded in the EU." Many observers see this recent statement by European agricultural commissioner Franz Fischler as a clear signal towards a nearby lifting of the quasi EU moratorium on transgenic crops (or GMs for short) launched in 1998 (European Commission 2002). One of the last obstacles towards lifting the moratorium, however, is the problem of coexistence. How can GM-crops and non-GM-crops coexist? Since the European Environmental Agency published its...

  8. Chimera states: Coexistence of coherence and incoherence in networks of coupled oscillators

    Panaggio, Mark J; Abrams, Daniel M.

    2014-01-01

    A chimera state is a spatio-temporal pattern in a network of identical coupled oscillators in which synchronous and asynchronous oscillation coexist. This state of broken symmetry, which usually coexists with a stable spatially symmetric state, has intrigued the nonlinear dynamics community since its discovery in the early 2000s. Recent experiments have led to increasing interest in the origin and dynamics of these states. Here we review the history of research on chimera states and highlight...

  9. Search for shape coexistence in odd - Z rare earth proton emitters

    Nuclear shapes are very sensitive to the structural effects and can change with isospin and from one nucleus to its neighbour and in some cases configurations corresponding to different shapes may coexist at similar energies which may arise from intruder excitations. Search for such interesting phenomena of shape coexistence and rapidly changing shapes in the less explored region of rare earth odd Z nuclei from Z = 51 to 75 are the focus of present work

  10. The coexistence of seven sympatric fulvettas in Ailao Mountains, Ejia Town, Yunnan Province

    Xia, Ji; Wu, Fei; HU, Wan-Zhao; FANG, Jian-Ling; Yang, Xiao-Jun

    2015-01-01

    The coexistence of ecologically similar species sharing sympatric areas is a central issue of community ecology. Niche differentiation is required at least in one dimension to avoid competitive exclusion. From 2012-2014, by adopting the methods of mist-nets and point counts to evaluate spatial niche partitioning and morphological differentiations, we explored the coexistence mechanisms of seven sympatric fulvettas in Ailao Mountains, Ejia town, Yunnan Province, China. The microhabitats of the...

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

    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.

  12. Solar Energetic Particles: Sampling Coronal Abundances

    Reames, Donald V.

    1998-05-01

    In the large solar energetic particle (SEP) events, coronal mass ejections (CMEs) drive shock waves out through the corona that accelerate elements of the ambient material to MeV energies in a fairly democratic, temperature-independent manner. These events provide the most complete source of information on element abundances in the corona. Relative abundances of 22 elements from H through Zn display the well-known dependence on the first ionization potential (FIP) that distinguishes coronal and photospheric material. For most elements, the main abundance variations depend upon the gyrofrequency, and hence on the charge-to-mass ratio, Q/A, of the ion. Abundance variations in the dominant species, H and He, are not Q/A dependent, presumably because of non-linear wave-particle interactions of H and He during acceleration. Impulsive flares provide a different sample of material that confirms the Ne:Mg:Si and He/C abundances in the corona.

  13. Coexistence of resistance to thyroid hormone and papillary thyroid carcinoma

    Igata, Motoyuki; Tsuruzoe, Kaku; Kawashima, Junji; Kukidome, Daisuke; Kondo, Tatsuya; Motoshima, Hiroyuki; Shimoda, Seiya; Furukawa, Noboru; Nishikawa, Takeshi; Miyamura, Nobuhiro

    2016-01-01

    Summary Resistance to thyroid hormone (RTH) is a syndrome of reduced tissue responsiveness to thyroid hormones. RTH is majorly caused by mutations in the thyroid hormone receptor beta (THRB) gene. Recent studies indicated a close association of THRB mutations with human cancers, but the role of THRB mutation in carcinogenesis is still unclear. Here, we report a rare case of RTH with a papillary thyroid carcinoma (PTC). A 26-year-old woman was referred to our hospital due to a thyroid tumor and hormonal abnormality. She had elevated serum thyroid hormones and non-suppressed TSH levels. Genetic analysis of THRB identified a missense mutation, P452L, leading to a diagnosis of RTH. Ultrasound-guided fine-needle aspiration biopsy of the tumor and lymph nodes enabled the cytological diagnosis of PTC with lymph node metastases. Total thyroidectomy and neck lymph nodes dissection were performed. Following surgery, thyroxine replacement (≥500 μg) was necessary to avoid the symptoms of hypothyroidism and to maintain her TSH levels within the same range as before the operation. During the follow-up, basal thyroglobulin (Tg) levels were around 6 ng/ml and TSH-stimulated Tg levels were between 12 and 20 ng/ml. Up to present, the patient has had no recurrence of PTC. This indicates that these Tg values are consistent with a biochemical incomplete response or an indeterminate response. There is no consensus regarding the management of thyroid carcinoma in patients with RTH, but aggressive treatments such as total thyroidectomy followed by radioiodine (RAI) and TSH suppression therapy are recommended. Learning points There are only a few cases reporting the coexistence of RTH and thyroid carcinoma. Moreover, our case would be the first case presenting one with lymph node metastases. Recent studies indicated a close association of THRB mutations with human cancers, but the role of THRB mutation in carcinogenesis is still unclear. When total thyroidectomy is performed in

  14. Fuel breaks affect nonnative species abundance in Californian plant communities

    Merriam, K.E.; Keeley, J.E.; Beyers, J.L.

    2006-01-01

    We evaluated the abundance of nonnative plants on fuel breaks and in adjacent untreated areas to determine if fuel treatments promote the invasion of nonnative plant species. Understanding the relationship between fuel treatments and nonnative plants is becoming increasingly important as federal and state agencies are currently implementing large fuel treatment programs throughout the United States to reduce the threat of wildland fire. Our study included 24 fuel breaks located across the State of California. We found that nonnative plant abundance was over 200% higher on fuel breaks than in adjacent wildland areas. Relative nonnative cover was greater on fuel breaks constructed by bulldozers (28%) than on fuel breaks constructed by other methods (7%). Canopy cover, litter cover, and duff depth also were significantly lower on fuel breaks constructed by bulldozers, and these fuel breaks had significantly more exposed bare ground than other types of fuel breaks. There was a significant decline in relative nonnative cover with increasing distance from the fuel break, particularly in areas that had experienced more numerous fires during the past 50 years, and in areas that had been grazed. These data suggest that fuel breaks could provide establishment sites for nonnative plants, and that nonnatives may invade surrounding areas, especially after disturbances such as fire or grazing. Fuel break construction and maintenance methods that leave some overstory canopy and minimize exposure of bare ground may be less likely to promote nonnative plants. ?? 2006 by the Ecological Society of America.

  15. Microhabitat locality allows multi-species coexistence in terrestrial plant communities.

    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

  16. Silicon abundances in population I giants

    Boehm-Vitense, Erika

    1992-01-01

    Silicon to carbon abundance ratios for population I giants were determined from emission lines originating in the transition layers between stellar chromospheres and coronae. For effective temperatures larger than 6200 K we find a group of stars with increased silicon to carbon but normal nitrogen to carbon abundance ratios. These stars are presumably descendents from Ap stars with increased surface silicon to carbon abundance ratios. For G stars this anomaly disappears as is to be expected due to the increased depth of the convection zone and therefore deeper mixing which dilutes the surface overabundances. The disappearance of the abundance anomalies proves that the anomalous abundances observed for the F giants are indeed only a surface phenomenon. It also proves that the same holds for their progenitors, the Ap and Am stars, as has been generally believed. Unexplained is the increased silicon to carbon abundance ratio observed for several stars cooler than 5100 L. RS CVn and related stars do not show this increased abundance ratio. There are also some giants which appear to be enriched in carbon, perhaps due to a helium flash with some mixing if the star is a clump star.

  17. Predicting the dynamics of protein abundance.

    Mehdi, Ahmed M; Patrick, Ralph; Bailey, Timothy L; Bodén, Mikael

    2014-05-01

    Protein synthesis is finely regulated across all organisms, from bacteria to humans, and its integrity underpins many important processes. Emerging evidence suggests that the dynamic range of protein abundance is greater than that observed at the transcript level. Technological breakthroughs now mean that sequencing-based measurement of mRNA levels is routine, but protocols for measuring protein abundance remain both complex and expensive. This paper introduces a Bayesian network that integrates transcriptomic and proteomic data to predict protein abundance and to model the effects of its determinants. We aim to use this model to follow a molecular response over time, from condition-specific data, in order to understand adaptation during processes such as the cell cycle. With microarray data now available for many conditions, the general utility of a protein abundance predictor is broad. Whereas most quantitative proteomics studies have focused on higher organisms, we developed a predictive model of protein abundance for both Saccharomyces cerevisiae and Schizosaccharomyces pombe to explore the latitude at the protein level. Our predictor primarily relies on mRNA level, mRNA-protein interaction, mRNA folding energy and half-life, and tRNA adaptation. The combination of key features, allowing for the low certainty and uneven coverage of experimental observations, gives comparatively minor but robust prediction accuracy. The model substantially improved the analysis of protein regulation during the cell cycle: predicted protein abundance identified twice as many cell-cycle-associated proteins as experimental mRNA levels. Predicted protein abundance was more dynamic than observed mRNA expression, agreeing with experimental protein abundance from a human cell line. We illustrate how the same model can be used to predict the folding energy of mRNA when protein abundance is available, lending credence to the emerging view that mRNA folding affects translation efficiency

  18. CUMULATIVE OXYGEN ABUNDANCES OF SPIRAL GALAXIES

    Studying the global evolution of spiral galaxies requires determining their overall chemical compositions. However, since spirals tend to possess gradients in their chemical compositions, determining their overall chemical abundances poses a challenge. In this study, the framework for a newly proposed method for determining the overall oxygen abundance of a disk is established. By separately integrating the absolute amounts of hydrogen and oxygen out to large radii, the cumulative oxygen abundance is shown to approach an asymptotic value. In this manner, a reliable account of the overall chemical state of a disk is revealed.

  19. Lithium Abundance of Metal-poor Stars

    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).

  20. Study of the primordial lithium abundance

    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.

  1. Abundance analysis of HD 22920 spectra

    Khalack, Viktor

    2015-01-01

    The new spectropolarimetric observations of HD 22920 with ESPaDOnS at CFHT reveal a strong variability of its spectral line profiles with the phase of stellar rotation. We have obtained Teff = 13640 K, logg=3.72 for this star from the best fit of its nine Balmer line profiles. The respective model of stellar atmosphere was calculated to perform abundance analysis of HD 22920 using the spectra obtained for three different phases of stellar rotation. We have found that silicon and chromium abundances appear to be vertically stratified in the atmosphere of HD 22920. Meanwhile, silicon shows hints for a possible variability of vertical abundance stratification with rotational phase.

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

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

    2006-09-01

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

  3. Massive Access Control Aided by Knowledge-Extraction for Co-Existing Periodic and Random Services over Wireless Clinical Networks.

    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. PMID:27240842

  4. Complete sequences of KPC-2-encoding plasmid p628-KPC and CTX-M-55-encoding p628-CTXM coexisted in Klebsiella pneumoniae

    Wang, Li; Fang, Haihong; Feng, Jiao; Yin, Zhe; Xie, Xiaofang; Zhu, Xueming; Wang, Jie; Chen, Weijun; Yang, Ruisheng; Du, Hong; Zhou, Dongsheng

    2015-01-01

    A carbapenem-resistant Klebsiella pneumoniae strain 628 was isolated from a human case of intracranial infection in a Chinese teaching hospital. Strain 628 produces KPC-2 and CTX-M-55 encoded by two different conjugative plasmids, i.e., the IncFIIK plasmid p628-KPC and the IncI1 plasmid p628-CTXM respectively. blaKPC−2 is captured by a Tn1722-based unit transposon with a linear structure. ΔTn3-ISKpn27-blaKPC−2-ΔISKpn6-ΔTn1722 and this transposon together with a mercury resistance (mer) gene locus constitutes a 34 kb acquired drug-resistance region. blaKPC−2 has two transcription starts (nucleotides G and C located at 39 and 250 bp upstream of its coding region respectively) which correspond to two promoters, i.e., the intrinsic P1 and the upstream ISKpn27/Tn3-provided P2 with the core −35/−10 elements TAATCC/TTACAT and TTGACA/AATAAT respectively. blaCTX−M−55 is mobilized in an ISEcp1-blaCTX−M−55-Δorf477 transposition unit and appears to be the sole drug-resistant determinant in p628-CTXM. blaCTX−M−55 possesses a single transcription start (nucleotides G located at 116 bp upstream of its coding region) corresponding to the ISEcp1-provided P1 promoter with the core −35/−10 element TTGAAA/TACAAT. All the above detected promoters display a characteristic of constitutive expression. Coexistence of blaKPC and blaCTX−M in K. pneumoniae has been reported many times but this is the first report to gain deep insights into genetic platforms, promoters, and expression of the two coexisting bla genes with determination of entire nucleotide sequences of the two corresponding plasmids. PMID:26347725

  5. Iron abundance in the atmosphere of Arcturus

    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] $=-0.48 \\pm 0.02$.

  6. Chemical abundance analysis of 19 barium stars

    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...

  7. SWFSC/MMTD: Vaquita Abundance Survey 1997

    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...

  8. Chinook Abundance - Linear Features [ds181

    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...

  9. Testing Relationships between Energy and Vertebrate Abundance

    Understanding what drives variation in the abundance of organisms is fundamental to evolutionary ecology and wildlife management. Yet despite its importance, there is still great uncertainty about the main factors influencing variation in vertebrate abundance across taxa. We believe valuable knowledge and increased predictive power could be gained by taking into account both the intrinsic factors of species and the extrinsic factors related to environmental surroundings in the commonly cited RQ model, which provides a simple conceptual framework valid at both the interspecific and the intraspecific scales. Approaches comparing studies undertaken at different spatial and taxonomic scales could be key to our ability to better predict abundance, and thanks to the increased availability of population size data, global geographic datasets, and improved comparative methods, there might be unprecedented opportunities to (1) gain a greater understanding of vertebrate abundance patterns and (2) test existing theories on free-ranging animals.

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

    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.

  11. Primordial Deuterium Abundance and Cosmic Baryon Density

    Hogan, Craig J.

    1994-01-01

    The comparison of cosmic abundances of the light elements with the density of baryonic stars and gas in the universe today provides a critical test of big bang theory and a powerful probe of the nature of dark matter. A new technique allows determination of cosmic deuterium abundances in quasar absorption clouds at large redshift, allowing a new test of big bang homogeneity in diverse, very distant systems. The first results of these studies are summarized, along with their implications. The ...

  12. Unprecedented accurate abundances: signatures of other Earths?

    Melendez, J.; Asplund, M.; Gustafsson, B.; Yong, D.; Ramirez, I.

    2009-01-01

    For more than 140 years the chemical composition of our Sun has been considered typical of solar-type stars. Our highly differential elemental abundance analysis of unprecedented accuracy (~0.01 dex) of the Sun relative to solar twins, shows that the Sun has a peculiar chemical composition with a ~20% depletion of refractory elements relative to the volatile elements in comparison with solar twins. The abundance differences correlate strongly with the condensation temperatures of the elements...

  13. Estimating whale abundance using sparse hydrophone arrays

    Harris, Danielle Veronica

    2012-01-01

    Passive acoustic monitoring has been used to investigate many aspects of marine mammal ecology, although methods to estimate absolute abundance and density using acoustic data have only been developed in recent years. The instrument configuration in an acoustic survey determines which abundance estimation methods can be used. Sparsely distributed arrays of instruments are useful because wide geographic areas can be covered. However, instrument spacing in sparse arrays is such that the same...

  14. Spatial scaling of species abundance distributions

    Borda-de-Água, Luís; Borges, Paulo A. V.; Hubbell, Stephen P.; Pereira, Henrique M

    2012-01-01

    Copyright © 2012 The Authors. Ecography © 2012 Nordic Society Oikos. Species abundance distributions are an essential tool in describing the biodiversity of ecological communities. We now know that their shape changes as a function of the size of area sampled. Here we analyze the scaling properties of species abundance distributions by using the moments of the logarithmically transformed number of individuals. We find that the moments as a function of area size are well fitted by power law...

  15. How selection structures species abundance distributions

    Magurran, A.E; Henderson, P. A.

    2012-01-01

    How do species divide resources to produce the characteristic species abundance distributions seen in nature? One way to resolve this problem is to examine how the biomass (or capacity) of the spatial guilds that combine to produce an abundance distribution is allocated among species. Here we argue that selection on body size varies across guilds occupying spatially distinct habitats. Using an exceptionally well-characterized estuarine fish community, we show that biomass is concentrated in l...

  16. Solar Models with New Low Metal Abundances

    Yang, Wuming

    2016-04-01

    In the past decade, the photospheric abundances of the Sun had been revised several times by many observers. The standard solar models constructed with the new low-metal abundances disagree with helioseismic results and detected neutrino fluxes. The solar model problem has puzzled some stellar physicists for more than 10 years. Rotation, enhanced diffusion, convection overshoot, and magnetic fields are used to reconcile the new abundances with helioseismology. The too low helium subsurface abundance in enhanced diffusion models can be improved by the mixing caused by rotation and magnetic fields. The problem of the depth of the convective zone in rotating models can be resolved by convection overshoot. Consequently, the Asplund–Grevesse–Sauval rotation model including overshooting (AGSR) reproduces the seismically inferred sound-speed and density profiles and the convection zone depth as well as the Grevesse & Sauval model computed before. But this model fails to reproduce the surface helium abundance, which is 0.2393 (2.6σ away from the seismic value), and neutrino fluxes. The magnetic model called AGSM keeps the agreement of the AGSR and improves the prediction of the surface helium abundance. The observed separation ratios r02 and r13 are reasonably reproduced by AGSM. Moreover, neutrino fluxes calculated by this model are not far from the detected neutrino fluxes and the predictions of previous works.

  17. Report on carbon and nitrogen abundance studies

    Boehm-Vitense, Erika

    1991-01-01

    The aim of the proposal was to determine the nitrogen to carbon abundance ratios from transition layer lines in stars with different T(sub eff) and luminosities. The equations which give the surface emission line fluxes and the measured ratio of the NV to CIV emission line fluxes are presented and explained. The abundance results are compared with those of photospheric abundance studies for stars in common with the photospheric investigations. The results show that the analyses are at least as accurate as the photospheric determinations. These studies can be extended to F and early G stars for which photospheric abundance determinations for giants are hard to do because molecular bands become too weak. The abundance determination in the context of stellar evolution is addressed. The N/C abundance ratio increases steeply at the point of evolution for which the convection zone reaches deepest. Looking at the evolution of the rotation velocities v sin i, a steep decrease in v sin i is related to the increasing depth of the convection zone. It is concluded that the decrease in v sin i for T(sub eff) less than or approximately = 5800 K is most probably due to the rearrangement of the angular momentum in the stars due to deep convective mixing. It appears that the convection zone is rotating with nearly depth independent angular momentum. Other research results and ongoing projects are discussed.

  18. TEA: A Code Calculating Thermochemical Equilibrium Abundances

    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. Modelling Void Abundance in Modified Gravity

    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...

  20. Few-group condensation via two-material coexisting ring model for fast reactor core analysis

    Highlights: • A two-material coexisting ring model is proposed to improve few-group collapsing in fast reactor analysis. • In newly proposed model, the coupling coefficients between two-material are introduced. • The proposed method is effective in calculating few-group XS compared to conventional method. - Abstract: To improve the currently used simplified fast reactor analysis method for few-group condensation, a two-material coexisting ring model is proposed in this study. In the two-material coexisting ring model, the θ-direction homogenized model from the R–θ–Z geometry is solved, but the neutron flux for each material in the homogenized region is obtained separately. In the numerical results on simple 2-D fast reactor test problems, the newly proposed two-material coexisting ring model shows excellent neutron spectrum agreement with the reference, as compared to the conventional simplified model. In addition, the few-group calculation result shows better keff estimation when a two-material coexisting ring model is used for group condensation. Because relative errors on the neutron spectrum are much flattened when the newly proposed model is used, accurate few-group cross sections can be generated even if a small few-group structure is selected for condensation

  1. Local Distribution and coexistence of prevalent tree species in peat swamp forests of Central Kalimantan

    Herwint Simbolon

    2009-12-01

    Full Text Available SIMBOLON, H. 2009. Local Distribution and coexistence of prevalent tree species in peat swamp forests of Central Kalimantan. Reinwardtia 12(5: 373–382. ⎯ A study on the distribution and coexistence of prevalent tree species in peat swamp forests was conducted at Lahei and Kelampangan, Central Kalimantan. The prevalent species in both sites were Calophyllum canum, Combretocarpus rotundatus, Cratoxylum glaucum, Ctenolophon parvifolius, Elaeocarpus petiolatus, with Palaquium cochleariifolium at Kelampangan, and Buchanania sessifolia, Madhuca sericea, Semecarpus sp., Shorea balangeran, Tetractomia obovata and Vatica oblongifolia at Lahei plot. The prevalent species were randomly distributed, however, when individuals were grouped into mature vs juvenile, the mature individuals of C. parvifolius tended to be clumped and the juvenile were randomly distributed; while in C. rotundatus, the mature individuals were randomly distributed and the juvenile were clumped. Pattern of the coexistence among the prevalent species in the study site were associated, and independent relationships, and almost no exclusion relationship was found. Independent and associated relationships among the coexisting species may be one of the explanations of the mechanism which maintain relatively high diversity of plant species in the tropical peat swamp forests, which has extreme habitat conditions and narrow habitat heterogeneity. Pattern of the coexistence relationships among mature vs juvenile individuals of the same species varied.

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

    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.

  3. Testing for effects of climate change on competitive relationships and coexistence between two bird species.

    Stenseth, Nils Chr; Durant, Joël M; Fowler, Mike S; Matthysen, Erik; Adriaensen, Frank; Jonzén, Niclas; Chan, Kung-Sik; Liu, Hai; De Laet, Jenny; Sheldon, Ben C; Visser, Marcel E; Dhondt, André A

    2015-05-22

    Climate change is expected to have profound ecological effects, yet shifts in competitive abilities among species are rarely studied in this context. Blue tits (Cyanistes caeruleus) and great tits (Parus major) compete for food and roosting sites, yet coexist across much of their range. Climate change might thus change the competitive relationships and coexistence between these two species. Analysing four of the highest-quality, long-term datasets available on these species across Europe, we extend the textbook example of coexistence between competing species to include the dynamic effects of long-term climate variation. Using threshold time-series statistical modelling, we demonstrate that long-term climate variation affects species demography through different influences on density-dependent and density-independent processes. The competitive interaction between blue tits and great tits has shifted in one of the studied sites, creating conditions that alter the relative equilibrium densities between the two species, potentially disrupting long-term coexistence. Our analyses show that long-term climate change can, but does not always, generate local differences in the equilibrium conditions of spatially structured species assemblages. We demonstrate how long-term data can be used to better understand whether (and how), for instance, climate change might change the relationships between coexisting species. However, the studied populations are rather robust against competitive exclusion. PMID:25904659

  4. Clonal growth and plant species abundance

    Herben, Tomáš; Nováková, Zuzana; Klimešová, Jitka

    2014-01-01

    Background and Aims Both regional and local plant abundances are driven by species' dispersal capacities and their abilities to exploit new habitats and persist there. These processes are affected by clonal growth, which is difficult to evaluate and compare across large numbers of species. This study assessed the influence of clonal reproduction on local and regional abundances of a large set of species and compared the predictive power of morphologically defined traits of clonal growth with data on actual clonal growth from a botanical garden. The role of clonal growth was compared with the effects of seed reproduction, habitat requirements and growth, proxied both by LHS (leaf–height–seed) traits and by actual performance in the botanical garden. Methods Morphological parameters of clonal growth, actual clonal reproduction in the garden and LHS traits (leaf-specific area – height – seed mass) were used as predictors of species abundance, both regional (number of species records in the Czech Republic) and local (mean species cover in vegetation records) for 836 perennial herbaceous species. Species differences in habitat requirements were accounted for by classifying the dataset by habitat type and also by using Ellenberg indicator values as covariates. Key Results After habitat differences were accounted for, clonal growth parameters explained an important part of variation in species abundance, both at regional and at local levels. At both levels, both greater vegetative growth in cultivation and greater lateral expansion trait values were correlated with higher abundance. Seed reproduction had weaker effects, being positive at the regional level and negative at the local level. Conclusions Morphologically defined traits are predictive of species abundance, and it is concluded that simultaneous investigation of several such traits can help develop hypotheses on specific processes (e.g. avoidance of self-competition, support of offspring) potentially

  5. Linking species abundance distributions in numerical abundance and biomass through simple assumptions about community structure

    Henderson, Peter A.; Magurran, Anne E

    2010-01-01

    Species abundance distributions (SADs) are widely used as a tool for summarizing ecological communities but may have different shapes, depending on the currency used to measure species importance. We develop a simple plotting method that links SADs in the alternative currencies of numerical abundance and biomass and is underpinned by testable predictions about how organisms occupy physical space. When log numerical abundance is plotted against log biomass, the species lie within an approximat...

  6. Poplar and its bacterial endophytes: coexistence and harmony

    van der Lelie, D.; Taghavi, S.; Monchy, S.; Schwender, J.; Miller, L.; Ferrieri, R.; Rogers, A.; Zhu, W.; Weyens, N.; Vangronsveld, J.; Newman, L.

    2009-09-01

    Associations between plants and microorganisms are very complex and are the subject of an increasing number of studies. Here, we specifically address the relationship between poplar and its endophytic bacteria. The role and importance of endophytic bacteria in growth and development of their host plants is still underestimated. However, since many endophytes have a beneficial effect on their host, an improved understanding of the interaction between poplar and its endophytic bacteria has the potential to provide major breakthroughs that will improve the productivity of poplar. Endophytic bacteria can improve plant growth and development in a direct or indirect way. Direct plant growth promoting mechanisms may involve nitrogen fixation, production of plant growth regulators such as auxins, cytokinins and gibberellins, and suppression of stress ethylene synthesis by 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. Endophytic bacteria can indirectly benefit the plant by preventing the growth or activity of plant pathogens through competition for space and nutrients, antibiosis, production of hydrolytic enzymes, inhibition of pathogen-produced enzymes or toxins, and through systemic induction of plant defense mechanisms. Examples of applications for custom endophyte-host partnerships include improved productivity and establishment of poplar trees on marginal soils and the phytoremediation of contaminated soils and groundwater. A systems biology approach to understand the synergistic interactions between poplar and its beneficial endophytic bacteria represents an important field of research, which is facilitated by the recent sequencing of the genomes of poplar and several of its endophytic bacteria.

  7. Coexistence of phases in asymmetric nuclear matter under strong magnetic fields

    Aguirre, R

    2014-01-01

    The equation of state of nuclear matter is strongly affected by the presence of a magnetic field. Here we study the equilibrium configuration of asymmetric nuclear matter for a wide range of densities, isospin composition, temperatures and magnetic fields. Special attention is paid to the low density and low temperature domain, where a thermodynamical instability exists. Neglecting fluctuations of the Coulomb force, a coexistence of phases is found under such conditions, even for extreme magnetic intensities. We describe the nuclear interaction by using the non--relativistic Skyrme potential model within a Hartree--Fock approach. We found that the coexistence of phases modifies the equilibrium configuration, masking most of the manifestations of the spin polarized matter. However, the compressibility and the magnetic susceptibility show clear signals of this fact. Thermal effects are significative for both quantities, mainly out of the coexistence region.

  8. Acquired phototrophy stabilises coexistence and shapes intrinsic dynamics of an intraguild predator and its prey.

    Moeller, Holly V; Peltomaa, Elina; Johnson, Matthew D; Neubert, Michael G

    2016-04-01

    In marine ecosystems, acquired phototrophs - organisms that obtain their photosynthetic ability by hosting endosymbionts or stealing plastids from their prey - are omnipresent. Such taxa function as intraguild predators yet depend on their prey to periodically obtain chloroplasts. We present a new theory for the effects of acquired phototrophy on community dynamics by analysing a mathematical model of this predator-prey interaction and experimentally verifying its predictions with a laboratory model system. We show that acquired phototrophy stabilises coexistence, but that the nature of this coexistence exhibits a 'paradox of enrichment': as light increases, the coexistence between the acquired phototroph and its prey transitions from a stable equilibrium to boom-bust cycles whose amplitude increases with light availability. In contrast, heterotrophs and mixotrophic acquired phototrophs (that obtain   95% of carbon from photosynthesis) acquired phototrophs form blooms. PMID:26833622

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

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

  10. Co-Existence of Peri-Ampullary Carcinoma with Peripancreatic Tuberculous Lymphadenopathy

    Shah S

    2004-05-01

    Full Text Available CONTEXT: Pancreatic tuberculosis and peripancreatic tuberculous lymphadenitis are rare, mimicking various pathologies of the pancreas. The coexistence of peri-ampullary malignancy with peripancreatic tuberculous lymphadenitis has not been reported. CASE REPORT: We present the case of a young woman who had been operated on with a preoperative diagnosis of peri-ampullary adenocarcinoma in whom a frozen section of regional lymph nodes revealed tuberculosis. The final pathology confirmed the co-existence of tuberculosis with malignancy. The patient made an uneventful recovery. CONCLUSION: In countries with high endemicity for tuberculosis, the co-existence of malignancy and tuberculosis should be considered and resection, which is the only chance for cure, should not be abandoned due to observations based solely on frozen sections.

  11. Performance analysis of coexisting IEEE 802.15.4-based health monitoring WBANs.

    Deylami, Mohammad; Jovanov, Emil

    2012-01-01

    Wireless Body Area Networks (WBANs) for health monitoring systems are required to meet stringent performance demands regarding the tradeoff between reliability, latency, and power efficiency. WBANs feature limited range and bandwidth and they are prone to interference. Considering the life-critical nature of some WBAN systems, we present an in-depth investigation of the situations where the dynamic coexistence of multiple WBANs may severely affect their performances. In this paper, we analytically study the effect of coexistence on the operation of WBANs. We present a mathematical analysis to precisely obtain the probabilities of successful communication and validate this analysis through simulation. Our simulation analysis indicates that in the default mode of operation, coexistence of three WBANs can lead to the loss of 20-85% of data transmissions for typical sensor configurations. PMID:23366424

  12. Coexistence of WiFi and WiMAX systems based on PS-request protocols.

    Kim, Jongwoo; Park, Suwon; Rhee, Seung Hyong; Choi, Yong-Hoon; Chung, Young-uk; Hwang, Ho Young

    2011-01-01

    We introduce both the coexistence zone within the WiMAX frame structure and a PS-Request protocol for the coexistence of WiFi and WiMAX systems sharing a frequency band. Because we know that the PS-Request protocol has drawbacks, we propose a revised PS-Request protocol to improve the performance. Two PS-Request protocols are based on the time division operation (TDO) of WiFi system and WiMAX system to avoid the mutual interference, and use the vestigial power management (PwrMgt) bit within the Frame Control field of the frames transmitted by a WiFi AP. The performance of the revised PS-Request protocol is evaluated by computer simulation, and compared to those of the cases without a coexistence protocol and to the original PS-Request protocol. PMID:22163721

  13. GMO neighbourhoods - will co-existence be a geographically realistic possibility?

    Qvist, H. Witt; Lundsgaard, H.; Brandt, Jesper

    2006-01-01

    of the precautionary principle adopted in the Maastricht treaty from 1992 by the EU (Andersen, 2000). We concretised these rules in relation to actual landscape practices among primary producers of sugar beet in Denmark, we simulated the co-existence of GM and conventional sugar beet in an area of...... after the study took place. It is concluded that although the farmers are positive towards the possibility of introducing GM sugar beet, it is not realistic to expect the rules of co-existence to be observed, which makes the risk assessment behind the new rules unrealistical. Further studies of social...... practice in relation to trends and geographical variations in the distribution of structure, size and fragmentation of agricultural holdings are recommended in order to investigate possibilities for realistic co-existence....

  14. Good abundances from bad spectra; 1, techniques

    Bryn, J; Wyse, R F G; Gilmore, Gerard; Wyse, Rosemary F G

    1995-01-01

    We have developed techniques to extract true iron abundances and surface gravities from spectra of the type provided by the multiple-object fibre-fed spectroscopic radial-velocity surveys underway with 2dF, HYDRA, NESSIE, and the forthcoming Sloan survey. Our method is optimised for low S/N, intermediate resolution blue spectra of G stars. Spectroscopic indices sensitive to iron abundance and gravity are defined from a set of narrow (few Angstrom) wavelength intervals, and calibrated using synthetic spectra. We have also defined a single abundance indicator which is able to provide useful iron abundance information from spectra having S/N ratios as low as 10 per Angstrom. The theoretical basis and calibration using synthetic spectra are described in this paper. The empirical calibration of these techniques by application to observational data is described in Jones, Wyse and Gilmore (PASP July 1995). The technique provides precise iron abundances, with zero-point correct to \\sim 0.1 dex, and is reliable, with ...

  15. Oxygen abundance maps of CALIFA galaxies

    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...

  16. Abundances of Molecular Species in Barnard 68

    Francesco, J D; Welch, W J; Bergin, E A; Francesco, James Di; Hogerheijde, Michiel R.; Welch, William J.; Bergin, Edwin A.

    2002-01-01

    Abundances for 5 molecules (C18O, CS, NH3, H2CO, and C3H2) and 1 molecular ion (N2H+) and upper limits for the abundances of 1 molecule (13CO) and 1 molecular ion (HCO+) are derived for gas within the Bok globule Barnard 68 (B68). The abundances were determined using our own BIMA millimeter interferometer data and single-dish data gathered from the literature, in conjunction with a Monte Carlo radiative transfer model. Since B68 is the only starless core to have its density structure strongly constrained via extinction mapping, a major uncertainty has been removed from these determinations. All abundances for B68 are lower than those derived for translucent and cold dense clouds, but perhaps only significantly for N2H+, NH3, and C3H2. Depletion of CS toward the extinction peak of B68 is hinted at by the large offset between the extinction peak and the position of maximum CS line brightness. Abundances derived here for C18O and N2H+ are consistent with other, recently determined values at positions observed in...

  17. Synchronization transition of a coupled system composed of neurons with coexisting behaviors near a Hopf bifurcation

    The coexistence of a resting condition and period-1 firing near a subcritical Hopf bifurcation point, lying between the monostable resting condition and period-1 firing, is often observed in neurons of the central nervous systems. Near such a bifurcation point in the Morris—Lecar (ML) model, the attraction domain of the resting condition decreases while that of the coexisting period-1 firing increases as the bifurcation parameter value increases. With the increase of the coupling strength, and parameter and initial value dependent synchronization transition processes from non-synchronization to compete synchronization are simulated in two coupled ML neurons with coexisting behaviors: one neuron chosen as the resting condition and the other the coexisting period-1 firing. The complete synchronization is either a resting condition or period-1 firing dependent on the initial values of period-1 firing when the bifurcation parameter value is small or middle and is period-1 firing when the parameter value is large. As the bifurcation parameter value increases, the probability of the initial values of a period-1 firing neuron that lead to complete synchronization of period-1 firing increases, while that leading to complete synchronization of the resting condition decreases. It shows that the attraction domain of a coexisting behavior is larger, the probability of initial values leading to complete synchronization of this behavior is higher. The bifurcations of the coupled system are investigated and discussed. The results reveal the complex dynamics of synchronization behaviors of the coupled system composed of neurons with the coexisting resting condition and period-1 firing, and are helpful to further identify the dynamics of the spatiotemporal behaviors of the central nervous system. (general)

  18. Stand dynamics and tree coexistence in an analytical structured model: the role of recruitment.

    Angulo, Óscar; Bravo de la Parra, Rafael; López-Marcos, Juan C; Zavala, Miguel A

    2013-09-21

    Understanding the mechanisms of coexistence and niche partitioning in plant communities is a central question in ecology. Current theories of forest dynamics range between the so-called neutral theories which assume functional equivalence among coexisting species to forest simulators that explain species assemblages as the result of tradeoffs in species individual strategies at several ontogenetic stages. Progress in these questions has been hindered by the inherent difficulties of developing analytical size-structured models of stand dynamics. This precludes examination of the relative importance of each mechanism on tree coexistence. In previous simulation and analytical studies emphasis has been given to interspecific differences at the sapling stage, and less so to interspecific variation in seedling recruitment. In this study we develop a partial differential equation model of stand dynamics in which competition takes place at the recruitment stage. Species differ in their size-dependent growth rates and constant mortality rates. Recruitment is described as proportional to the basal area of conspecifics, to account for fecundity and seed supply per unit of basal area, and is corrected with a decreasing function of species specific basal area to account for competition. We first analyze conditions for population persistence in monospecific stands and second we investigate conditions of coexistence for two species. In the monospecific case we found a stationary stand structure based on an inequality between mortality rate and seed supply. In turn, intra-specific competition does not play any role on the asymptotic extinction or population persistence. In the two-species case we found that coexistence can be attained when the reciprocal negative effect on recruitment follows a given relation with respect to intraspecific competition. Specifically a tradeoff between recruitment potential (i.e. shade tolerance or predation avoidance) and fecundity or growth rate

  19. Phase coexistence and its implications on the functional properties of the room-temperature giant magnetocaloric alloy Fe-Rh

    We study the thermomagnetic history effects arising due to phase coexistence and metastability across the first order antiferromagnetic to ferromagnetic transition in the giant magnetocaloric Fe-Rh alloy near room temperature. Magnetic force microscopy is used to visualize the phase coexistence across this magneto structural transition at sub-micrometer length scales. These local measurements provide direct evidence of strong coupling between the elastic and electronic degrees of freedom, which is thought to give rise to phase coexistence at micrometer scales. Phase coexistence and the associated history effects are shown to influence the functional properties of Fe-Rh like giant magnetocaloric effect at room temperature. (author)

  20. Characterization of two coexisting pathogen populations of Leptosphaeria spp., the cause of stem canker of brassicas

    Joanna Kaczmarek

    2012-12-01

    Full Text Available Stem canker of brassicas, also known as blackleg is the most damaging disease of many Brassicaceae. The disease is caused by Leptosphaeria maculans (Desm. Ces et de Not. and L. biglobosa sp. nov., Shoemaker & Brun, which coexist in plants and resulting in disease symptoms and decreased yield, quantity and quality of cultivated vegetables and oilseed rape. The paper presents taxonomic relationships between these coexisting pathogen species, describes particular stages of their life cycles, summarizes the differences between the species, and reviews methods for their identification.

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

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

    2016-01-01

    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 greater...... currently applied in Germany are joint and strict liability for all damages. Our results further show that neighbours do not cause a problem and opportunities for reducing costs through agreements with them exist. Finally, we find that farmers’ attitudes towards GM crops affect the probability of adoption...

  2. Shape coexistence and the N=28 shell closure far from stability

    Sarazin, F.; Savajols, H.; Mittig, W. [and others

    1999-07-01

    The masses of 31 neutron rich nuclei in the range A=29-47 have been measured. The precision of 19 masses has been significantly improved and 12 masses were measured for the first time. The neutron rich Cl, S and P isotopes are seen to exhibit a change in shell structure around N=28. Comparison with shell model and relativistic mean field calculations demonstrate that deformed prolate ground state configurations associated with shape coexistence are necessary to explain the experimental data. Direct evidence for shape coexistence is found in the observation of an isomer in {sup 43}S. (authors)

  3. Coexistence and asymptotic periodicity in a competitor-competitor-mutualist model

    Gan, Wenzhen; Lin, Zhigui

    2008-01-01

    In this paper, the competitor-competitor-mutualist three-species Lotka-Volterra model is discussed. Firstly, by Schauder fixed point theory, the coexistence state of the strongly coupled system is given. Applying the method of upper and lower solutions and its associated monotone iterations, the true solutions are constructed. Our results show that this system possesses at least one coexistence state if cross-diffusions and cross-reactions are weak. Secondly, the existence and asymptotic behavior of T-periodic solutions for the periodic reaction-diffusion system under homogeneous Dirichlet boundary conditions are investigated. Sufficient conditions which guarantee the existence of T-periodic solution are also obtained.

  4. Congenital bronchial atresia coexistent with intralobar pulmonary sequestration: a case report

    Han, Young Min; Ku, Ja Hong; Lee, Dong Keun; Chung, Kyung Ho; Kim, Chong Soo; Sohn, Myung Hee; Choi, Ki Chul [Chonbuk National University Medical School, Jeonju (Korea, Republic of)

    1995-02-15

    Bronchial atresia coexistent with intralobar pulmonary sequestration is so rare that only two cases have been reported in the literature. We report a case of congential bronchial atresia coexistent with intralobar pulmonary sequestation in a 51-year-old woman. Computed tomography showed the branching mass with hyperinflation of adjacent pulmonary parenchyma in the medial segment of the right middle lobe and a large thin-walled cystic mass with air-fluid levels in the medial basal segment of the right lower lobe. Selective inferior phrenic arteriography showed two aberrant arteries supplying the large cystic mass in the right lower lobe. The venous drainage was through the right pulmonary vein.

  5. Thin-thick coexistence behavior of 8CB liquid crystalline films on silicon

    R. Garcia; Subashi, E.; Fukuto, M.

    2007-01-01

    The wetting behavior of thin films of 4'-n-octyl-4-cyanobiphenyl (8CB) on Si is investigated via optical and x-ray reflectivity measurement. An experimental phase diagram is obtained showing a broad thick-thin coexistence region spanning the bulk isotropic-to-nematic ($T_{IN}$) and the nematic-to-smectic-A ($T_{NA}$) temperatures. For Si surfaces with coverages between 47 and $72\\pm3$ nm, reentrant wetting behavior is observed twice as we increase the temperature, with separate coexistence be...

  6. Chimera states: coexistence of coherence and incoherence in networks of coupled oscillators

    Panaggio, Mark J.; Abrams, Daniel M.

    2015-03-01

    A chimera state is a spatio-temporal pattern in a network of identical coupled oscillators in which synchronous and asynchronous oscillation coexist. This state of broken symmetry, which usually coexists with a stable spatially symmetric state, has intrigued the nonlinear dynamics community since its discovery in the early 2000s. Recent experiments have led to increasing interest in the origin and dynamics of these states. Here we review the history of research on chimera states and highlight major advances in understanding their behaviour.

  7. Twin pregnancy with both complete hydatiform mole and coexistent alive fetus:case report

    Achour Radhouane; Ben Aissa Imen; NEJI Khaled

    2015-01-01

    Twin pregnancy consisting of a complete hydatidiform mole coexisting with a live fetus is a rare condition with an incidence of 1 in 22 000 to 1 in 1 00 000 pregnancies. Clinical information is limited and management is difficult due to the risk of pregnancy complications such as fetal death, vaginal bleeding, preeclampsia, hyperthyroidism, and the risk of persistent gestational trophoblastic disease. Thus, the report described about the change of size and implantation site of the molar mass coexisting with a live fetus is rare especially about sonographic findings such as echo patterns. Recently we experienced a case of complete hydatidiform mole with a healthy infant delivered at term.

  8. Age-abundance relationships for neutral communities

    Danino, Matan; Shnerb, Nadav M.

    2015-10-01

    Neutral models for the dynamics of a system of competing species are often used to describe a wide variety of empirical communities. These models are used in many situations, ranging from population genetics and ecological biodiversity to macroevolution and cancer tumors. One of the main issues discussed within this framework is the relationships between the abundance of a species and its age. Here we provide a comprehensive analysis of the age-abundance relationships for fixed-size and growing communities. Explicit formulas for the average and the most likely age of a species with abundance n are given, together with the full probability distribution function. We further discuss the universality of these results and their applicability to the tropical forest community.

  9. Estimating the relationship between abundance and distribution

    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...

  10. Unprecedented accurate abundances: signatures of other Earths?

    Melendez, J; Gustafsson, B; Yong, D; Ramírez, I

    2009-01-01

    For more than 140 years the chemical composition of our Sun has been considered typical of solar-type stars. Our highly differential elemental abundance analysis of unprecedented accuracy (~0.01 dex) of the Sun relative to solar twins, shows that the Sun has a peculiar chemical composition with a ~20% depletion of refractory elements relative to the volatile elements in comparison with solar twins. The abundance differences correlate strongly with the condensation temperatures of the elements. A similar study of solar analogs from planet surveys shows that this peculiarity also holds in comparisons with solar analogs known to have close-in giant planets while the majority of solar analogs without detected giant planets show the solar abundance pattern. The peculiarities in the solar chemical composition can be explained as signatures of the formation of terrestrial planets like our own Earth.

  11. Beryllium Abundances in Solar Mass Stars

    Krugler, J. A.; Boesgaard, A. M.

    2008-08-01

    Light element abundance analysis allows for a deeper understanding of the chemical composition of a star beneath its surface. Beryllium provides a probe down to 3.5×106 K, where it fuses with protons. In this study, Be abundances were determined for 52 F and G dwarfs selected from a sample of local thin disc stars. These stars were selected by mass to range from 0.9 to 1.1 M⊙. They have effective temperatures from 5600 to 6400 K, and their metallicities [Fe/H]=-0.65 to +0.11. The data were taken with the Keck HIRES instrument and the Gecko spectrograph on the Canada France Hawaii Telescope. The abundances were calculated via spectral synthesis and were analyzed to investigate the Be abundance as a function of age, temperature, metallicity, and its relation to the lithium abundance for this narrow mass range. Be is found to decrease linearly with metallicity down to [Fe/H]˜-4.0 with slope 0.86 ± 0.02. The relation of the Be abundance to effective temperature is dependent upon metallicity, but when metallicity effects are taken into account, there is a spread ˜1.2 dex. We find a 1.5 dex spread in A(Be) when plotted against age, with the largest spread occurring from 6-8 Gyr. The relation with Li is found to be linear with slope 0.36 ± 0.06 for the temperature regime of 5900-6300 K.

  12. Airborne Measurements of Coarse Mode Aerosol Composition and Abundance

    Froyd, K. D.; Murphy, D. M.; Brock, C. A.; Ziemba, L. D.; Anderson, B. E.; Wilson, J. C.

    2015-12-01

    Coarse aerosol particles impact the earth's radiative balance by direct scattering and absorption of light and by promoting cloud formation. Modeling studies suggest that coarse mode mineral dust and sea salt aerosol are the dominant contributors to aerosol optical depth throughout much of the globe. Lab and field studies indicate that larger aerosol particles tend to be more efficient ice nuclei, and recent airborne measurements confirm the dominant role of mineral dust on cirrus cloud formation. However, our ability to simulate coarse mode particle abundance in large scale models is limited by a lack of validating measurements above the earth's surface. We present airborne measurements of coarse mode aerosol abundance and composition over several mid-latitude, sub-tropical, and tropical regions from the boundary layer to the stratosphere. In the free troposphere the coarse mode constitutes 10-50% of the total particulate mass over a wide range of environments. Above North America mineral dust typically dominates the coarse mode, but biomass burning particles and sea salt also contribute. In remote environments coarse mode aerosol mainly consists of internally mixed sulfate-organic particles. Both continental and marine convection can enhance coarse aerosol mass through direct lofting of primary particles and by secondary accumulation of aerosol material through cloud processing.

  13. Resonance ionization mass spectrometry for isotopic abundance measurements

    Miller, C. M.

    1986-01-01

    Resonance ionization mass spectrometry (RIMS) is a relatively new laser-based technique for the determination of isotopic abundances. The resonance ionization process depends upon the stepwise absorption of photons from the laser, promoting atoms of the element of interest through progressively higher electronic states until an ion is formed. Sensitivity arises from the efficiency of the resonant absorption process when coupled with the power available from commercial laser sources. Selectivity derives naturally from the distinct electronic structure of different elements. This isobaric discrimination has provided the major impetus for development of the technique. Resonance ionization mass spectrometry was used for analysis of the isotopic abundances of the rare earth lutetium. Isobaric interferences from ytterbium severely effect the ability to measure small amounts of the neutron-deficient Lu isotopes by conventional mass spectrometric techniques. Resonance ionization for lutetium is performed using a continuous-wave laser operating at 452 nm, through a sequential two-photon process, with one photon exciting the intermediate resonance and the second photon causing ionization. Ion yields for microgram-sized quantities of lutetium lie between 10(6) and 10(7) ions per second, at overall ionization efficiencies approaching 10(-4). Discrimination factors against ytterbium greater than 10(6) have been measured. Resonance ionization for technetium is also being explored, again in response to an isobaric interference, molybdenum. Because of the relatively high ionization potential for Tc, three-photon, two-color RIMS processes are being developed.

  14. Metal Abundances in Hot DO White Dwarfs

    Werner, K; Ringat, E; Kruk, J W

    2012-01-01

    The relatively high abundance of carbon in the hot DO white dwarf RE0503-289 indicates that it is a descendant of a PG1159 star. This is corroborated by the recent detection of the extremely high abundances of trans-Fe elements which stem from s-process nucleosynthesis in the precursor AGB star, dredged up by a late He-shell flash and possibly amplified by radiative levitation. On the other hand, the hottest known DO white dwarf, KPD0005+5106, cannot have evolved from a PG1159 star but represents a distinct He-rich evolutionary sequence that possibly originates from a binary white dwarf merger.

  15. Overexpression Analysis of emv2 gene coding for Late Embryogenesis Abundant Protein from Vigna radiata (Wilczek

    Rajesh S.

    2008-10-01

    Full Text Available Late embryogenesis abundant (LEA proteins are speculated to protect against water stress deficit in plants. An over expression system for mungbean late embryogenesis abundant protein, emv2 was constructed in a pET29a vector, designated pET-emv2 which is responsible for higher expression under the transcriptional/translational control of T7/lac promoter incorporated in the Escherichia coli BL21 (DE3.Induction protocol was optimized for pET recombinants harboring the target gene. Overexpressed EMV2 protein was purified to homogeneity and the protein profile monitored by SDS-PAGE.

  16. Non-Salmonid Abundance - Line Features [ds186

    California Department of Resources — The CalFish Abundance Database contains a comprehensive collection of anadromous fisheries abundance information. The "Other Fish" category contains data collected...

  17. North Sea Elasmobranchs: distribution, abundance and biodiversity

    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 survey

  18. Heavy element abundances and massive star formation

    Wang, Boqi; Silk, Joseph

    1993-01-01

    The determination of the stellar initial mass function (IMF) remains a great challenge in astronomy. In the solar neighborhood, the IMF is reasonable well determined for stellar masses from about 0.1 to 60 solar mass. However, outside the solar neighborhood, the IMF is poorly known. Among those frequently discussed arguments favoring a different IMF outside the solar neighborhood are the estimated time to consume the remaining gas in spiral galaxies, and the high rate of forming massive stars in starburst galaxies. An interesting question then is whether there may be an independent way of testing possible variations in the IMF. Indeed, the heavy elements in the interstellar medium are mostly synthesized in massive stars, so increasing, or decreasing, the fraction of massive stars naturally leads to a variation in the heavy element yield, and thus, the metallicity. The observed abundance should severely constrain any deviations of the IMF from the locally determined IMF. We focus on element oxygen, which is the most abundant heavy element in the interstellar medium. Oxygen is ejected only by massive stars that can become Type 1 supernovae, and the oxygen abundance is, therefore, a sensitive function of the fraction of massive stars in the IMF. Adopting oxygen enables us to avoid uncertainties in Type 1 supernovae. We use the nucleosynthesis results to calculate the oxygen yield for given IMF. We then calculate the oxygen abundance in the interstellar medium assuming instantaneous recycling of oxygen.

  19. The Galactic Thick Disk Stellar Abundances

    Prochaska, J X; Carney, B W; McWilliam, A; Wolfe, A M; Prochaska, Jason X.; Naumov, Sergei O.; Carney, Bruce W.; William, Andrew Mc; Wolfe, Arthur M.

    2000-01-01

    We present first results from a program to measure the chemical abundances of a large (N>30) sample of thick disk stars with the principal goal of investigating the formation history of the Galactic thick disk. Our analysis confirms previous studies of O and Mg in the thick disk stars which reported enhancements in excess of the thin disk population. Furthermore, the observations of Si, Ca, Ti, Mn, Co, V, Zn, Al, and Eu all argue that the thick disk population has a distinct chemical history from the thin disk. With the exception of V and Co, the thick disk abundance patterns match or tend towards the values observed for halo stars with [Fe/H]~-1. This suggests that the thick disk stars had a chemical enrichment history similar to the metal-rich halo stars. With the possible exception of Si, the thick disk abundance patterns are in excellent agreement with the chemical abundances observed in the metal-poor bulge stars suggesting the two populations formed from the same gas reservoir at a common epoch. We disc...

  20. The Abundance of Large Arcs From CLASH

    Xu, Bingxiao; Postman, Marc; Meneghetti, Massimo; Coe, Dan A.; Clash Team

    2015-01-01

    We have developed an automated arc-finding algorithm to perform a rigorous comparison of the observed and simulated abundance of large lensed background galaxies (a.k.a arcs). We use images from the CLASH program to derive our observed arc abundance. Simulated CLASH images are created by performing ray tracing through mock clusters generated by the N-body simulation calibrated tool -- MOKA, and N-body/hydrodynamic simulations -- MUSIC, over the same mass and redshift range as the CLASH X-ray selected sample. We derive a lensing efficiency of 15 ± 3 arcs per cluster for the X-ray selected CLASH sample and 4 ± 2 arcs per cluster for the simulated sample. The marginally significant difference (3.0 σ) between the results for the observations and the simulations can be explained by the systematically smaller area with magnification larger than 3 (by a factor of ˜4) in both MOKA and MUSIC mass models relative to those derived from the CLASH data. Accounting for this difference brings the observed and simulated arc statistics into full agreement. We find that the source redshift distribution does not have big impact on the arc abundance but the arc abundance is very sensitive to the concentration of the dark matter halos. Our results suggest that the solution to the "arc statistics problem" lies primarily in matching the cluster dark matter distribution.

  1. Will Abundant Natural Gas Solve Climate Change?

    McJeon, H. C.; Edmonds, J.; Bauer, N.; Leon, C.; Fisher, B.; Flannery, B.; Hilaire, J.; Krey, V.; Marangoni, G.; Mi, R.; Riahi, K.; Rogner, H.; Tavoni, M.

    2015-12-01

    The rapid deployment of hydraulic fracturing and horizontal drilling technologies enabled the production of previously uneconomic shale gas resources in North America. Global deployment of these advanced gas production technologies could bring large influx of economically competitive unconventional gas resources to the energy system. It has been hoped that abundant natural gas substituting for coal could reduce carbon dioxide (CO2) emissions, which in turn could reduce climate forcing. Other researchers countered that the non-CO2 greenhouse gas (GHG) emissions associated with shale gas production make its lifecycle emissions higher than those of coal. In this study, we employ five state-of-the-art integrated assessment models (IAMs) of energy-economy-climate systems to assess the full impact of abundant gas on climate change. The models show large additional natural gas consumption up to +170% by 2050. The impact on CO2 emissions, however, is found to be much smaller (from -2% to +11%), and a majority of the models reported a small increase in climate forcing (from -0.3% to +7%) associated with the increased use of abundant gas. Our results show that while globally abundant gas may substantially change the future energy market equilibrium, it will not significantly mitigate climate change on its own in the absence of climate policies.

  2. Abundance of Terrestrial Planets by Microlensing

    Yock, Philip

    2000-01-01

    Terrestrial planets may be detected using the gravitational microlensing technique. This was demonstrated in the high magnification event MACHO-98-BLG-35. Observing strategies aimed at measuring the abundance of terrestrial planets are discussed, using both existing telescopes and planned telescopes.

  3. Quasar Elemental Abundances at High Redshifts

    Dietrich, M.; Hamann, F.; Shields, J. C.; Constantin, A.; Heidt, J.; Jaeger, K.; Vestergaard, Marianne; Wagner, S. J.

    2003-01-01

    framework of the most recent photoionization models to estimate the metallicity of the gas associated with the high-z quasars. Standard photoionization parameters and the assumption of secondary nitrogen enrichment indicate an average abundance of Z/Z_sol = 4 to 5 in the line emitting gas. Assuming a time...

  4. Stability switches and multistability coexistence in a delay-coupled neural oscillators system.

    Song, Zigen; Xu, Jian

    2012-11-21

    In this paper, we present a neural network system composed of two delay-coupled neural oscillators, where each of these can be regarded as the dynamical system describing the average activity of neural population. Analyzing the corresponding characteristic equation, the local stability of rest state is studied. The system exhibits the switch phenomenon between the rest state and periodic activity. Furthermore, the Hopf bifurcation is analyzed and the bifurcation curve is given in the parameters plane. The stability of the bifurcating periodic solutions and direction of the Hopf bifurcation are exhibited. Regarding time delay and coupled weight as the bifurcation parameters, the Fold-Hopf bifurcation is investigated in detail in terms of the central manifold reduction and normal form method. The neural system demonstrates the coexistence of the rest states and periodic activities in the different parameter regions. Employing the normal form of the original system, the coexistence regions are illustrated approximately near the Fold-Hopf singularity point. Finally, numerical simulations are performed to display more complex dynamics. The results illustrate that system may exhibit the rich coexistence of the different neuro-computational properties, such as the rest states, periodic activities, and quasi-periodic behavior. In particular, some periodic activities can evolve into the bursting-type behaviors with the varying time delay. It implies that the coexistence of the quasi-periodic activity and bursting-type behavior can be obtained if the suitable value of system parameter is chosen. PMID:22921877

  5. Testing for effects of climate change on competitive relationships and coexistence between two bird species

    Stenseth, Nils Chr.; Durant, Joel M.; Fowler, Mike S.; Matthysen, Erik; Adriaensen, Frank; Jonzen, Niclas; Chan, Kung-Sik; Liu, Hai; De Laet, Jenny; Sheldon, Ben C.; Visser, Marcel E.; Dhondt, Andre A.

    2015-01-01

    Climate change is expected to have profound ecological effects, yet shifts in competitive abilities among species are rarely studied in this context. Blue tits (Cyanistes caeruleus) and great tits (Parus major) compete for food and roosting sites, yet coexist across much of their range. Climate chan

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

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

    2014-01-01

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

  7. Variational approach to shape coexistence in sup 6 sup 8 Se

    Petrovici, A; Faessler, A

    2002-01-01

    Results are presented on shape coexistence and neutron-proton correlations at low and high spins in the N=Z nucleus sup 6 sup 8 Se obtained within the complex version of the Excited Vampir variational approach. Effects of possible contaminations due to the center of momentum motion on the lowest two positive-parity bands are discussed.

  8. Carbon and oxygen isotopes in apatite CO2 and co-existing calcite

    Carbon and oxygen isotopes were analyzed in carbonate apatite CO2 and in co-existing calcite. Both C and O in apatite CO2 are enriched in the respective light isotopes relative to calcite. These results confirm the proposition that carbonate is part of the apatite structure

  9. Isolated sphenoid fungal sinusitis and coexisting intrasellar mass lesion presenting with headache as the sole symptom

    A case of isolated sphenoid fungal sinusitis in an elderly diabetic patient is described. A coexisting mass lesion located in the sellar region was detected incidentally. Coincidence of these two entities represents a potential surgical disaster which may result in direct intracranial spread of fungal infection

  10. Characteristics of titanium oxide memristor with coexistence of dopant drift and a tunnel barrier

    Tian, Xiao-Bo; Xu, Hui

    2014-06-01

    The recent published experimental data of titanium oxide memristor devices which are tested under the same experimental conditions exhibit the strange instability and complexity of these devices. Such undesired characteristics preclude the understanding of the device conductive processes and the memristor-based practical applications. The possibility of the coexistence of dopant drift and tunnel barrier conduction in a memristor provides preliminary explanations for the undesired characteristics. However, current research lacks detailed discussion about the coexistence case. In this paper, dopant drift and tunnel barrier-based theories are first analyzed for studying the relations between parameters and physical variables which affect characteristics of memristors, and then the influences of each parameter change on the conductive behaviors in the single and coexistence cases of the two mechanisms are simulated and discussed respectively. The simulation results provide further explanations of the complex device conduction. Theoretical methods of eliminating or reducing the coexistence of the two mechanisms are proposed, in order to increase the stability of the device conduction. This work also provides the support for optimizing the fabrications of memristor devices with excellent performance.

  11. Shape Coexistence in Neutron-Deficient At Isotopes in Relativistic Mean-Field Model

    2007-01-01

    The potential energy surfaces are calculated for neutron-deficient At isotopes from A = 190 to 207 in an axiaJJy deformed relativistic mean-field approach, using a quadratic constraint scheme for the first time. We find several minima in the potential energy surface for each nucleus, shape-coexistence, and quadratic deform are discussed.

  12. Shape Coexistence and Band Termination in the Doubly Magic Nucleus 40Ca

    DONGBao-guo; GUOHong-chao

    2003-01-01

    Shape coexistence and band structure near yrast line of the Z=N doubly magic nucleus 40Ca have been investigated by the configuration-dependent cranked Nilsson-Strutinsky approach and the calculated bands show good agreement with experimental observations at high spin. The observed normal deformed and superdeformed bands are explained theoretically and the terminating states are confirmed by the calculations.

  13. Hyperkalaemia in diabetes mellitus--potential hazards of coexisting hyporeninaemic hypoaldosteronism.

    Large, D M; Carr, P. H.; Laing, I; Davies, M.

    1984-01-01

    Two patients with insulin-dependent diabetes mellitus (Type I), developed severe, life-threatening hyperkalaemia, the first following treatment with spironolactone, the second during treatment for staphylococcal septicaemia when glucose-induced hyperkalaemia occurred. Investigations demonstrated co-existing hyporeininaemic hypoaldosteronism. Prompt recognition of this combined hormone-deficiency syndrome led to appropriate treatment and recovery. The biochemical features and clinical importan...

  14. Solid-State Coexistance of (Zr12) and (Zr6) Zirconium Oxocarboxylate Clusters

    Malaestean, Lurie [RWTH Aachen University; Alici, Meliha Kutluca [RWTH Aachen University; Besson, Claire [RWTH Aachen University; Ellern, Arkady [Ames Laboratory; Kogerler, Paul [RWTH Aachen University

    2013-10-30

    Ligand metathesis, Co(II) coordination, and partial condensation reactions of an archetypal {Zr6} zirconium oxocarboxylate cluster result in the first example of the coexistence of the distinct zirconium oxide frameworks {Zr6O8} and {Zr12O22}. Even minor modifications to the reaction conditions push this apparent equilibrium towards the {Zr6O8}-based product.

  15. The Myth of Coexistence: Why Transgenic Crops Are Not Compatible With Agroecologically Based Systems of Production

    Altieri, Miguel

    2005-01-01

    The coexistence of genetically modified (GM) crops and non-GM crops is a myth because the movement of transgenes beyond their intended destinations is a certainty, and this leads to genetic contamination of organic farms and other systems. It is unlikely that transgenes can be retracted once they have escaped, thus the damage to the purity of…

  16. Giant sigmoid diverticulum with coexisting metastatic rectal carcinoma: a case report.

    Sasi, Walid

    2010-01-01

    Giant diverticulum of the colon is a rare but clinically significant condition, usually regarded as a complication of an already existing colonic diverticular disease. This is the first report of a giant diverticulum of the colon with a co-existing rectal carcinoma.

  17. MRI Findings of Coexistence of Ectopic Neurohypophysis, Corpus Callosum Dysgenesis, and Periventricular Neuronal Heterotopia

    Harun Arslan

    2014-01-01

    Full Text Available Ectopic neurohypophysis is a pituitary gland abnormality, which can accompany growth hormone deficiency associated with dwarfism. Here we present magnetic resonance imaging (MRI findings of a rare case of ectopic neurohypophysis, corpus callosum dysgenesis, and periventricular neuronal heterotopia coexisting, with a review of the literature.

  18. The Emotional Readiness of Greek Cypriot Teachers for Peaceful Co-Existence

    Zembylas, Michalinos; Kendeou, Panayiota; Michaelidou, Athina

    2011-01-01

    In this article, we: (1) offer a conceptualisation of what it means for Greek Cypriot teachers to be "reconciled" with the "other side" (i.e. Turkish Cypriots) in Cyprus; (2) examine Greek Cypriot teachers' emotional responses to the new educational objective of cultivating peaceful coexistence in schools; and (3) investigate how Greek Cypriot…

  19. Meeting the Needs of Students with Coexisting Visual Impairments and Learning Disabilities

    Jones, Beth A.; Hensley-Maloney, Lauren

    2015-01-01

    The coexistence of visual impairments and learning disabilities presents unique challenges. It is imperative that teachers be apprised of the characteristics of this population as well as instructional strategies targeted at meeting their unique needs. The authors highlight typical patterns of performance and provide suggestions for effective…

  20. Effects of Coexisting Disorders on Cognition and Behavior in Children with ADHD

    Crawford, Susan G.; Kaplan, Bonnie J.; Dewey, Deborah

    2006-01-01

    Objective: To determine whether the presence of coexisting disorders affects memory, visual-motor skills, and daily functioning in children with ADHD. Method: Eighty-four boys and 18 girls (8 to 16 years old) participate in this study. Twenty children meet criteria for ADHD alone, 42 children for ADHD plus one other disorder, and 40 children for…

  1. Effects of species diversity on establishment and coexistence: a phylloplane fungal community model system.

    Stohr, S N; Dighton, J

    2004-10-01

    A model system was devised, evaluating the influence that species diversity (species richness) has on fungal establishment and coexistence. Seven members of the fungal phylloplane community of Vaccinium macrocarpon (American cranberry) were selected to assess how species diversity affected development and coexistence of another community member, Pestalotia vaccinii. Pestalotia was engaged in competitive interactions on 1% Malt Extract Agar (MEA) petri dishes with each of the seven individual saprotrophs (two-way interaction), in random combinations with three of the seven saprotrophs (four-way interaction), and in random combinations with five of the seven saprotrophs (six-way interaction). The saprotrophic fungi used in this study were Aspergillus sp., Alternaria alternata, Cladosporium cladosporoides, Curvularia lunata, Epicoccum purpuracens, Penicillium sp., and Pithomyces chartarum. We hypothesized that species diversity would have a significant impact on the establishment and coexistence of Pestalotia vaccinii in culture. In an effort to minimize density-dependent effects, the number of viable spores employed in the three types of interactions was kept constant. Target spore concentrations of 50 viable spores of P. vaccinii and 50 saprotroph spores were used, regardless of the number of species involved in the interaction. This proved to be a very important factor in the experiment. As our results show, species diversity had little or no effect on the establishment and coexistence of Pestalotia vaccinii; however, spore density played an extremely important role in the establishment and development of fungal propagules in our model. PMID:15692863

  2. Isolated sphenoid fungal sinusitis and coexisting intrasellar mass lesion presenting with headache as the sole symptom

    Kalaycı, Cem Burak; Çevik, Halime

    2014-01-01

    A case of isolated sphenoid fungal sinusitis in an elderly diabetic patient is described. A coexisting mass lesion located in the sellar region was detected incidentally. Coincidence of these two entities represents a potential surgical disaster which may result in direct intracranial spread of fungal infection.

  3. Value of petrosal sinus sampling: coexisting acromegaly, empty sella and meningioma

    Yarman, S. [Div. of Endocrinology, Metabolism and Nutrition, Istanbul Univ., Istanbul (Turkey); Minareci, Oe. [Dept. of Radiology, Medical Faculty of Istanbul Univ., Istanbul (Turkey)

    2004-12-01

    Simultaneous occurrence of an intracranial meningioma and a growth hormone (GH)-producing pituitary adenoma is exceedingly rare, as is coexistence of an empty sella and acromegaly. We report all these rare entities in the same patient. We evaluated the role of inferior petrosal sinus sampling for lateralisation of an adenoma in this patient. (orig.)

  4. Value of petrosal sinus sampling: coexisting acromegaly, empty sella and meningioma

    Simultaneous occurrence of an intracranial meningioma and a growth hormone (GH)-producing pituitary adenoma is exceedingly rare, as is coexistence of an empty sella and acromegaly. We report all these rare entities in the same patient. We evaluated the role of inferior petrosal sinus sampling for lateralisation of an adenoma in this patient. (orig.)

  5. A farmer's occupational airborne contact dermatitis masqueraded by coexisting rosacea: delayed diagnosis and legal acknowledgement.

    Spiewak, R.W.; Dutkiewicz, J

    2004-01-01

    A rare case of coexistence of occupational airborne dermatitis with rosacea is presented in a 41-year-old female farmer. Her first dermatitis symptoms appeared at the age of 10 when she started helping her parents on the farm. Uncovered skin areas of the face, neck, decollete, forearms and the hands

  6. High prevalence of coexisting prehypertension and prediabetes among healthy adults in northern and northeastern China

    Ding Hai-tao

    2011-10-01

    Full Text Available Abstract Background Prehypertension and prediabetes are major risk factors of cardiovascular disease, and their combined presence may result in more serious cardiovascular outcomes than expected with either prehypertension or prediabetes alone. The aim of the present study was to evaluate the prevalence of coexisting prehypertension and prediabetes, and the associated risk profiles in a Chinese population. Methods A cross-sectional survey in a representative sample of 3,595 men and 4,593 women aged 18 years and older was performed between 2008 and 2010. Prehypertension and prediabetes were diagnosed using the guidelines from the Seventh Report of the Joint National Committee on prevention, detection, and treatment of high blood pressure and American Diabetes Association, respectively. Prehypertension was defined as a systolic blood pressure of 120-139 mmHg and/or diastolic blood pressure of 80-89 mmHg, and prediabetes was defined as a fasting blood glucose of 5.6-6.9 mmol/L. Results The prevalence of coexisting prehypertension and prediabetes was 11.0%. Men had a higher prevalence of coexisting prehypertension and prediabetes than women (14.2% vs. 8.4%; P Conclusions There is a large proportion of Chinese adults with coexisting prehypertension and prediabetes. Thus, there is a need for more efforts that implement public health programs that target the earlier stages of hypertension and diabetes.

  7. A Possible Coexistence between Restless Leg Syndrom and Attention Deficit Hyperactivity Disorder

    Tilma, Jørgen; Thomsen, Per Hove; Ostergaard, John R

    2014-01-01

    Restless legs syndrome (RLS) and attention deficit hyperactivity disorder (ADHD) have consistently been found to coexist frequently. The cause for the relationship of these co-morbid disorders is contradicting, but both disorders are associated with a common dopaminergic dysfunction, low iron...

  8. A Rare Case of Paraovarian Cancer Coexisting with Cancer of the Fallopian Tube: Magnetic Resonance Appearance

    Primary paraovarian cancer is a rare tumor occurring in the female pelvis. Magnetic resonance imaging features of paraovarian cancer have not been previously reported. In the present report, we describe a case of paraovarian cancer coexisting with cancer of the fallopian tube and the magnetic resonance features

  9. Shape and rotational co-existence of N=Z nuclei around A ≅ 72 region

    It was observed that the shape isomerism in N=Z nucleus which at the same time supports the predicted scenario of oblate prolate shape co-existence in the medium mass region. 72Kr seems to be one of the rarer nuclei with a rather pure oblate deformed ground state and the oblate-prolate shape mixing found in the Kr isotopes

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

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

    2012-01-01

    inferences remains elusive. For example, would inferences of biotic interactions from broad-scale patterns of coexistence provide a surrogate for patterns at finer spatial scales? In this paper we examine how the spatial and environmental association between two closely related species of freshwater turtles...

  11. Coexistence of autoimmune diseases and autoantibodies in patients with myasthenia gravis

    Sibel Tamer

    2016-01-01

    Conclusions: MG has an increased frequency of coexisting ADs. Autoantibodies that are characteristic for ADs can be found in the patients without the presence of any of the clinical findings of ADs. Clinical attention towards the management of ADs is especially needed during the follow-up of patients with MG.

  12. Disentangling the nuclear shape coexistence in even-even Hg isotopes using the interacting boson model

    García-Ramos, J E

    2014-01-01

    We intend to provide a consistent description of the even-even Hg isotopes, 172-200Hg, using the interacting boson model including configuration mixing. We pay special attention to the description of the shape of the nuclei and to its connection with the shape coexistence phenomenon.

  13. Plant species coexistence alleviates the impacts of lead on Zea mays L.

    Ruyi Yang; Ling Liu; Shuting Zan; Jianjun Tang; Xin Chen

    2012-01-01

    Whether plant coexistence can reduce the impacts of lead(Pb)on crops in agroecosystems has not been well understood.We conducted a factorial experiment to investigate the effects of weeds coexisting with maize(Zea mays L.)on Pb accumulation in maize and soil microbes at two Pb levels(ambient and 300 mg/kg).Elevated Pb tended to increase the Pb concentration in maize and decreased soil microbial activity(indicated by the average well color development,AWCD),functional group diversity,as well as arbuscular mycorrhizal(AM)colonization and vesicle number of maize.Compared to the monoculture,weeds coexisting with maize reduced the Pb concentrations in the root,leaf,sheath and stem of maize at both seedling and mature stages.In maize-weed mixtures,soil microbial activity and functional group diversity tended to increase for both Pb treatments relative to the monoculture.Furthermore,principal component analysis revealed that the soil microbial community structure changed with the introduction of weeds.The highest Pb accumulation in weeds occurred for the elevated Pb treatment in a three species mixture.The results suggest that multiple plant species coexistence could reduce lead accumulation in crop plants and alleviate the negative impacts on soil microbes in polluted land,thereby highlighting the significance of plant diversity in agroecosystems.

  14. Fisetin: A Dietary Antioxidant for Health Promotion

    Khan, Naghma; Syed, Deeba N.; Ahmad, Nihal; Mukhtar, Hasan

    2013-01-01

    Significance: Diet-derived antioxidants are now being increasingly investigated for their health-promoting effects, including their role in the chemoprevention of cancer. In general, botanical antioxidants have received much attention, as they can be consumed for longer periods of time without any adverse effects. Flavonoids are a broadly distributed class of plant pigments that are regularly consumed in the human diet due to their abundance. One such flavonoid, fisetin (3,3′,4′,7-tetrahydrox...

  15. Chemical abundances and kinematics of barium stars

    de Castro, D. B.; Pereira, C. B.; Roig, F.; Jilinski, E.; Drake, N. A.; Chavero, C.; Silva, J. V. Sales

    2016-04-01

    In this paper we present an homogeneous analysis of photospheric abundances based on high-resolution spectroscopy of a sample of 182 barium stars and candidates. We determined atmospheric parameters, spectroscopic distances, stellar masses, ages, luminosities and scale height, radial velocities, abundances of the Na, Al, alpha-elements, iron-peak elements, and s-process elements Y, Zr, La, Ce, and Nd. We employed the local-thermodynamic-equilibrium model atmospheres of Kurucz and the spectral analysis code MOOG. We found that the metallicities, the temperatures and the surface gravities for barium stars can not be represented by a single gaussian distribution. The abundances of alpha-elements and iron peak elements are similar to those of field giants with the same metallicity. Sodium presents some degree of enrichment in more evolved stars that could be attributed to the NeNa cycle. As expected, the barium stars show overabundance of the elements created by the s-process. By measuring the mean heavy-element abundance pattern as given by the ratio [s/Fe], we found that the barium stars present several degrees of enrichment. We also obtained the [hs/ls] ratio by measuring the photospheric abundances of the Ba-peak and the Zr-peak elements. Our results indicated that the [s/Fe] and the [hs/ls] ratios are strongly anti-correlated with the metallicity. Our kinematical analysis showed that 90% of the barium stars belong to the thin disk population. Based on their luminosities, none of the barium stars are luminous enough to be an AGB star, nor to become self-enriched in the s-process elements. Finally, we determined that the barium stars also follow an age-metallicity relation.

  16. Chemical abundances and kinematics of barium stars

    de Castro, D. B.; Pereira, C. B.; Roig, F.; Jilinski, E.; Drake, N. A.; Chavero, C.; Sales Silva, J. V.

    2016-07-01

    In this paper, we present an homogeneous analysis of photospheric abundances based on high-resolution spectroscopy of a sample of 182 barium stars and candidates. We determined atmospheric parameters, spectroscopic distances, stellar masses, ages, luminosities and scaleheight, radial velocities, abundances of the Na, Al, α-elements, iron-peak elements, and s-process elements Y, Zr, La, Ce, and Nd. We employed the local thermodynamic equilibrium model atmospheres of Kurucz and the spectral analysis code MOOG. We found that the metallicities, the temperatures and the surface gravities for barium stars cannot be represented by a single Gaussian distribution. The abundances of α-elements and iron peak elements are similar to those of field giants with the same metallicity. Sodium presents some degree of enrichment in more evolved stars that could be attributed to the NeNa cycle. As expected, the barium stars show overabundance of the elements created by the s-process. By measuring the mean heavy-element abundance pattern as given by the ratio [s/Fe], we found that the barium stars present several degrees of enrichment. We also obtained the [hs/ls] ratio by measuring the photospheric abundances of the Ba-peak and the Zr-peak elements. Our results indicated that the [s/Fe] and the [hs/ls] ratios are strongly anticorrelated with the metallicity. Our kinematical analysis showed that 90 per cent of the barium stars belong to the thin disc population. Based on their luminosities, none of the barium stars are luminous enough to be an asymptotic giant branch star, nor to become self-enriched in the s-process elements. Finally, we determined that the barium stars also follow an age-metallicity relation.

  17. The behaviour of resistance and thermopower and the coexistence of two phases at metal-insulator transitions

    The coexistence of two phases at metal-insulator transition leads to peculiarities of the physical properties. This work reports on such peculiarities of the behaviour of the thermoelectric power and resistivity of vanadium oxides. An immediate proof for the coexistence of two phases is given by the behaviour of the X-ray reflexes. (author)

  18. A integração regional e a coexistência entre ALCA, MERCOSUL e comunidade andina

    Sergio Eduardo Canella

    2004-12-01

    Full Text Available The objective in this work is to verify the possibility of coexistence between the FTAA, MERCOSUL and Andean Community.O objetivo neste trabalho é verificar a possibilidade de coexistência entre a ALCA, MERCOSUL e Comunidade Andina.

  19. A Mean Field Model With Two Order Parameters for Three-Phase Coexistence Near the Tricritical Point

    SALİHOĞLU, S.

    1998-01-01

    This study gives a mean field model with two order parameters for three-phase coexistence near the multicritical point. The critical exponents calculated from our model are the tricritical exponents for the order parameters, susceptibility and the specific heat. Hence, our mean field model describes adequately the tricritical behaviour of a system in the region of three-phase coexistence.

  20. Coexistence of magneto-resistance and -capacitance tunability in Sm2Ga2Fe2O9

    Wu, Ye

    2016-01-01

    We propose that charge gradient resulting in the coexisting magneto-resistance and-capacitance tunability in material systems. We have experimentally observed coexisting of tunable magneto-resistance and -capacitance in Sm2Ga2Fe2O9. Our model fits well with the experimental result.

  1. Frequency of co-existence of dengue and malaria in patients presenting with acute febrile illness

    To find out the frequency of co-existence of malaria and dengue fever in patients presenting with acute febrile illness. Methods: The descriptive cross-sectional study was conducted at the Military Hospital Rawalpindi from June to November 2012. A total of 500 patients with complaint of acute febrile illness were selected after applying the inclusion and exclusion criteria. Preliminary data was collected on a pretested proforma. Blood samples of patients were tested for dengue serology and malaria parasite. Results were entered in respective proforma. Co-existence was considered present when a patient had both dengue serology and malaria parasite slide positive. SPSS 20 was used for data analysis. Result: Of the total, 349 (69.8%) were males and 151 (30.2%) females. Dengue serology was positive in 16 (3.2%); 81(16.2%) had malaria parasite slide positive; 403 (80.4%) had none of the two findings. Co-existence of both dengue and malaria was nil among the whole sample. In males, 67 (13.4%) had malaria, while 11 (2.2%) had dengue. In females, 14 (2.8%) had malaria, while 5 (1%) suffered from dengue fever. Conclusion: Co-existence of dengue and malaria was zero per cent in 500 patients visiting Military Hospital Rawalpindi. More studies shall be conducted to find out whether the reason of having zero per cent co-existence is that dengue or/and malaria epidemic did not occur in 2012 or whether there are some other factors involved. (author)

  2. Fallacies and fantasies: the theoretical underpinnings of the Coexistence Approach for palaeoclimate reconstruction

    Grimm, Guido W.; Potts, Alastair J.

    2016-03-01

    The Coexistence Approach has been used to infer palaeoclimates for many Eurasian fossil plant assemblages. However, the theory that underpins the method has never been examined in detail. Here we discuss acknowledged and implicit assumptions and assess the statistical nature and pseudo-logic of the method. We also compare the Coexistence Approach theory with the active field of species distribution modelling. We argue that the assumptions will inevitably be violated to some degree and that the method lacks any substantive means to identify or quantify these violations. The absence of a statistical framework makes the method highly vulnerable to the vagaries of statistical outliers and exotic elements. In addition, we find numerous logical inconsistencies, such as how climate shifts are quantified (the use of a "centre value" of a coexistence interval) and the ability to reconstruct "extinct" climates from modern plant distributions. Given the problems that have surfaced in species distribution modelling, accurate and precise quantitative reconstructions of palaeoclimates (or even climate shifts) using the nearest-living-relative principle and rectilinear niches (the basis of the method) will not be possible. The Coexistence Approach can be summarised as an exercise that shoehorns a plant fossil assemblage into coexistence and then assumes that this must be the climate. Given the theoretical issues and methodological issues highlighted elsewhere, we suggest that the method be discontinued and that all past reconstructions be disregarded and revisited using less fallacious methods. We outline six steps for (further) validation of available and future taxon-based methods and advocate developing (semi-quantitative) methods that prioritise robustness over precision.

  3. Coexistence of dopamine-beta-hydroxylase and activated protein-2 alpha in rat cerebellar Purkinje cells

    Kejian Wang; Wei Li; Shanquan Sun; Zhongqin Ren; Guiqiong He

    2009-01-01

    BACKGROUND:Tyrosine hydroxylase and phenylethanolamine-n-methyl transferase expression coexist in Purkinje cells of the rat cerebellum.Numerous reports have also been published addressing whether dopamine-beta-hydroxylase (DBH) expression exists in cerebellar Purkinje cells.OBJECTIVE:To investigate the coexistence of DBH and activator protein-2α expression in rat cerebellar Purkinje cells.DESIGN,TIME AND SETTING:A cell morphological study was performed at the Institute of Neuroscience,Chongqing Medical University,China in May 2007.MATERIALS:Ten healthy Wistar rats,of either gender,aged 14 weeks,served as experimental animals.Rabbit anti-mouse DBH,goat anti-mouse activator protein-2α and rabbit anti-mouse β-actin (Santa Cruz Biotechnology,Inc.,USA),horseradish peroxidase-labeled goat anti-rabbit IgG,FITC-labeled mouse anti-rabbit IgG,and Cy3-labeled mouse anti-goat IgG (Boster,Wuhan,China),were used in this study.METHODS:Immunohistochemical staining was used to measure the expression of DBH or activator protein-2α,with double-label immunofluorescence being employed to determine coexpression of both,in the cerebellum of 5 randomly selected rats.Western blot assay was utilized to determine the expression of DBH and activator protein-2α in the cerebellum of the remaining 5 rats.MAIN OUTCOME MEASURES:Expression,localization and coexistence of DBH and activator protein-2α in the cerebellum were measured separately.RESULTS:Immunohistochemical staining demonstrated that cerebellar Purkinje cells stained positive for DBH and activator protein-2α.Western blot assay also demonstrated DBH and activator protein-2α expression in the cerebellum.Double-labeling immunofluorescence showed the coexistence of DBH and activator protein-2α in cerebellar Purkinje cells.CONCLUSION:Norepinephrine and activator protein-2α coexist in rat cerebellar Purkinje cells.

  4. Relative abundance determinations in extremely metal poor giants. II. Transition probabilities and the abundance determinations

    The abundances of Fe and other elements are determined for a star of intermediate metallicity and for nine extremely metal poor stars, including two members of the globular cluster M92 and CD -38 deg 245. The accuracy of the transition probabilities for Fe I and other elements is evaluated. The distribution of the abundances of other elements with respect to Fe is the same for most of the cases studied. Manganese is the only element that shows a different relative abundance in an extremely metal poor star. 120 refs

  5. Deuterium Abundance in Consciousness and Current Cosmology

    Rauscher, Elizabeth A.

    We utilize the deuterium-hydrogen abundances and their role in setting limits on the mass and other conditions of cosmogenesis and cosmological evolution. We calculate the dependence of a set of physical variables such as density, temperature, energy mass, entropy and other physical variable parameters through the evolution of the universe under the Schwarzschild conditions as a function from early to present time. Reconciliation with the 3°K and missing mass is made. We first examine the Schwarzschild condition; second, the geometrical constraints of a multidimensional Cartesian space on closed cosmologies, and third we will consider the cosmogenesis and evolution of the universe in a multidimensional Cartesian space, obeying the Schwarzschild condition. Implications of this model for matter creation are made. We also examine experimental evidence for closed versus open cosmologies; x-ray detection of the "missing mass" density. Also the interstellar deuterium abundance, along with the value of the Hubble constant set a general criterion on the value of the curvature constant, k. Once the value of the Hubble constant, H is determined, the deuterium abundance sets stringent restrictions on the value of the curvature constant k by an detailed discussion is presented. The experimental evidences for the determination of H and the primary set of coupled equations to determine D abundance is given. 'The value of k for an open, closed, or flat universe will be discussed in terms of the D abundance which will affect the interpretation of the Schwarzschild, black hole universe. We determine cosmology solutions to Einstein's field obeying the Schwarzschild solutions condition. With this model, we can form a reconciliation of the black hole, from galactic to cosmological scale. Continuous creation occurs at the dynamic blackhole plasma field. We term this new model the multiple big bang or "little whimper model". We utilize the deuteriumhydrogen abundances and their role in

  6. Chemical abundance analysis of 19 barium stars

    Yang, Guo-Chao; Liang, Yan-Chun; Spite, Monique; Chen, Yu-Qin; Zhao, Gang; Zhang, Bo; Liu, Guo-Qing; Liu, Yu-Juan; Liu, Nian; Deng, Li-Cai; Spite, Francois; Hill, Vanessa; Zhang, Cai-Xia

    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 Teff, surface gravities log g, metallicity [Fe/H] and microturbulence velocity ξt) and equivalent widths of stellar absorption lines. These samples of Ba stars are giants as indicated by atmospheric parameters, metallicities and kinematic analysis about UVW velocity. Chemical abundances of 17 elements were obtained for these Ba stars. Their Na, Al, α- and iron-peak elements (O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Ni) are similar to the solar abundances. Our samples of Ba stars show obvious overabundances of neutron-capture (n-capture) process elements relative to the Sun. Their median abundances of [Ba/Fe], [La/Fe] and [Eu/Fe] are 0.54, 0.65 and 0.40, respectively. The Y I and Zr I abundances are lower than Ba, La and Eu, but higher than the α- and iron-peak elements for the strong Ba stars and similar to the iron-peak elements for the mild stars. There exists a positive correlation between Ba intensity and [Ba/Fe]. For the n-capture elements (Y, Zr, Ba, La), there is an anti-correlation between their [X/Fe] and [Fe/H]. We identify nine of our sample stars as strong Ba stars with [Ba/Fe] >0.6 where seven of them have Ba intensity Ba=2-5, one has Ba=1.5 and another one has Ba=1.0. The remaining ten stars are classified as mild Ba stars with 0.17<[Ba/Fe] <0.54.

  7. Sympatry and allopatry in two desert ant sister species: how do Cataglyphis bicolor and C. savignyi coexist?

    Dietrich, B; Wehner, R

    2003-06-01

    Two extremely morphologically similar sister species of desert ants, Cataglyphis bicolor and C. savignyi, exhibit broadly overlapping distributional ranges within Tunisia. In order to analyse the microhabitats of C. bicolor and C. savignyi within the sympatric and allopatric areas of both ant species, the plant species located at 113 different nest sites of the two ant species were determined. In the sympatric area, the two species exhibit a clear-cut nest site segregation. This is not the case in the allopatric areas. Hence the two species differentiate their microhabitat only when they are sympatric. The plant species associated mainly with the nest sites of C. bicolor indicate that this species prefers a type of vegetation that needs irrigation. This is in contrast to the nest sites of C. savignyi, which are usually found around plants that characterize typical dry steppe areas. As the ants' foraging paths recorded in the sympatric area reveal, C. bicolor performs significantly shorter foraging runs with respect to both length and time, and covers a much smaller foraging range than C. savignyi does. This result reflects the fact that the microhabitat occupied by the colonies of C. bicolor is richer in food abundance. When direct interspecific interactions were investigated by placing a bait midway between two heterospecific nests, C. bicolor foragers dominated over those of C. savignyi. The same dominance of C. bicolor over C. savignyi occurred in laboratory experiments. These results suggest that the dominant species drives the subordinate one out of the high quality microhabitats, and that the subordinate species is forced to survive in the less lucrative habitats. In conclusion, coexistence seems to be maintained by the asymmetric competitive relationship between the two species and the fact that the subordinate species has the ability to endure in the less favourable microhabitat. PMID:12720085

  8. The primordial deuterium abundance problems and prospects

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

    1997-01-01

    The current status of extragalactic deuterium abundance is discussed using two examples of `low' and `high' D/H measurements. We show that the discordance of these two types of D abundances may be a consequence of the spatial correlations in the stochastic velocity field. Within the framework of the generalized procedure (accounting for such effects) one finds good agreement between different observations and the theoretical predictions for standard big bang nucleosynthesis (SBBN). In particular, we show that the deuterium absorption seen at z = 2.504 toward Q1009+2956 and the H+D Ly-alpha profile observed at z = 0.701 toward Q1718+4807 are compatible with D/H $\\sim 4.1 - 4.6\\times10^{-5}$. This result supports SBBN and, thus, no inhomogeneity is needed. The problem of precise D/H measurements is discussed.

  9. The evolution of abundances in the galaxy

    This very brief review of the evolution of the abundances in our Galaxy first recalls the main observational facts regarding such abundances which have to be taken into account by any model of chemical evolution of our Galaxy. After having defined what are the crucial parameters which define such models, the emphasis is made on two approaches: the first analyzed by Vangioni--Flam and Audouze, 1988, and Andreani et al., 1988, in which the rate of star formation is bimodal i.e., is allowed to vary with time, and the second favoured by Matteucci and Francois, 1989, who invoke a multizone galactic model with infall (inflow) of external gas into the galactic disk. A list of problems to be considered in future work is finally proposed

  10. Helium abundance in the Orion A source

    The H, He 66α (22.4 GHz) and H, He 56α (36.5 GHz) recombination line observations were made at several positions of the central region of Orion A (R ∼ 3'). The observed relative helium abundance y' is found to increase with the angular distance from the nebular centre and to amount the mean value of 11.6% at the peripherycal positions. The comparison with the results of low frequency observations (H, He 109α, ν ∼ 5.0 GHz) shows that measurements towards the centre (y'=8-9%) is in agreement with the low frequency measurements of y', however y' at the peripherycal positions are higher than that at low frequency. The nebula model of a ''blister'' type is constructed to explain such behaviour. The conclusions are made that the actual helium abundance y in Orion A is ∼ 12%, the Orion Nebula expands and its radial velocity is ∼ 5 km/s

  11. Elemental Abundances in PG1159 Stars

    Werner, K; Reiff, E; Kruk, J W

    2007-01-01

    The hydrogen-deficiency in extremely hot post-AGB stars of spectral class PG1159 is probably caused by a (very) late helium-shell flash or a AGB final thermal pulse that consumes the hydrogen envelope, exposing the usually-hidden intershell region. Thus, the photospheric elemental abundances of these stars allow to draw conclusions about details of nuclear burning and mixing processes in the precursor AGB stars. We compare predicted elemental abundances to those determined by quantitative spectral analyses performed with advanced non-LTE model atmospheres. A good qualitative and quantitative agreement is found for many species (He, C, N, O, Ne, F, Si, Ar) but discrepancies for others (P, S, Fe) point at shortcomings in stellar evolution models for AGB stars. PG1159 stars appear to be the direct progeny of [WC] stars.

  12. Abundances in the diffuse interstellar medium

    The wealth of interstellar absorption line data obtained with the Copernicus and IUE satellites has opened up a new era in studies of the interstellar gas. It is now well established that certain elements, generally those with high condensation temperatures, are substantially under-abundant in the gas-phase relative to total solar or cosmic abundances. This depletion of elements is due to the existence of solid material in the form of dust grains in the interstellar medium. Surprisingly, however, recent surveys indicate that even volatile elements such as Zn and S are significantly depleted in many sight lines. Developments in this field which have been made possible by the large base of UV interstellar absorption line data built up over recent years are reviewed and the implications of the results for our understanding of the physical processes governing depletion are discussed. (author)

  13. Nitrous Oxide Production by Abundant Benthic Macrofauna

    Stief, Peter; Schramm, Andreas

    screened more than 20 macrofauna species for nitrous oxide production and identified filter-feeders and deposit-feeders that occur ubiquitously and at high abundance (e.g., chironomids, ephemeropterans, snails, and mussels) as the most important emitters of nitrous oxide. In contrast, predatory species......Detritivorous macrofauna species co-ingest large quantities of microorganisms some of which survive the gut passage. Denitrifying bacteria, in particular, become metabolically induced by anoxic conditions, nitrate, and labile organic compounds in the gut of invertebrates. A striking consequence...... that do not ingest large quantities of microorganisms produced insignificant amounts of nitrous oxide. Ephemera danica, a very abundant mayfly larva, was monitored monthly in a nitrate-polluted stream. Nitrous oxide production by this filter-feeder was highly dependent on nitrate availability...

  14. Attenuation of species abundance distributions by sampling.

    Shimadzu, Hideyasu; Darnell, Ross

    2015-04-01

    Quantifying biodiversity aspects such as species presence/ absence, richness and abundance is an important challenge to answer scientific and resource management questions. In practice, biodiversity can only be assessed from biological material taken by surveys, a difficult task given limited time and resources. A type of random sampling, or often called sub-sampling, is a commonly used technique to reduce the amount of time and effort for investigating large quantities of biological samples. However, it is not immediately clear how (sub-)sampling affects the estimate of biodiversity aspects from a quantitative perspective. This paper specifies the effect of (sub-)sampling as attenuation of the species abundance distribution (SAD), and articulates how the sampling bias is induced to the SAD by random sampling. The framework presented also reveals some confusion in previous theoretical studies. PMID:26064626

  15. Abundances in Damped Ly-alpha Galaxies

    Molaro, Paolo

    2005-01-01

    Damped Ly_alpha galaxies provide a sample of young galaxies where chemical abundances can be derived throughout the whole universe with an accuracy comparable to that for the local universe. Despite a large spread in redshift, HI column density and metallicity, DLA galaxies show a remarkable uniformity in the elemental ratios rather suggestive of similar chemical evolution if not of an unique population. These galaxies are characterized by a moderate, if any, enhancement of alpha-elements ove...

  16. Natural Resource Abundance and Human Capital Accumulation

    Jean-Philippe C. Stijns

    2001-01-01

    This study examines indicators of human capital accumulation together with data for natural resource abundance and rents in a panel of 102 countries running from 1970 to 1999. Mineral wealth makes a positive and marked difference on human capital accumulation. Matching on observables reveals that cross-country results are not driven by a third factor such as overall economic development. Political stability does seem to affect both human capital accumulation and subsoil wealth, but not enough...

  17. Chemical Abundance Inhomogeneities in Globular Cluster Stars

    Cohen, Judith G.

    2004-01-01

    It is now clear that abundance variations from star-to-star among the light elements, particularly C, N, O, Na and Al, are ubiquitous within galactic globular clusters; they appear seen whenever data of high quality is obtained for a sufficiently large sample of stars within such a cluster. The correlations and anti-correlations among these elements and the range of variation of each element appear to be independent of stellar evolutionary state, with the exception that enhanced depletion of ...

  18. Chemical Abundances and Milky Way Formation

    Gilmore, Gerry; Wyse, Rosemary F. G.

    2004-01-01

    Stellar chemical element ratios have well-defined systematic trends as a function of abundance, with an excellent correlation of these trends with stellar populations defined kinematically. This is remarkable, and has significant implications for Galactic evolution. The source function, the stellar Initial Mass Function, must be nearly invariant with time, place and metallicity. Each forming star must see a well-mixed mass-averaged IMF yield, implying low star formation rates, with most star ...

  19. Chemical abundances and kinematics of barium stars

    de Castro, D B; Roig, F; Jilinski, E; Drake, N A; Chavero, C; Silva, J V Sales

    2016-01-01

    In this paper we present an homogeneous analysis of photospheric abundances based on high-resolution spectroscopy of a sample of 182 barium stars and candidates. We determined atmospheric parameters, spectroscopic distances, stellar masses, ages, luminosities and scale height, radial velocities, abundances of the Na, Al, $alpha$-elements, iron-peak elements, and s-process elements Y, Zr, La, Ce, and Nd. We employed the local-thermodynamic-equilibrium model atmospheres of Kurucz and the spectral analysis code {\\sc moog}. We found that the metallicities, the temperatures and the surface gravities for barium stars can not be represented by a single gaussian distribution. The abundances of $alpha$-elements and iron peak elements are similar to those of field giants with the same metallicity. Sodium presents some degree of enrichment in more evolved stars that could be attributed to the NeNa cycle. As expected, the barium stars show overabundance of the elements created by the s-process. By measuring the mean heav...

  20. Water Abundance in Molecular Cloud Cores

    Snell, R L; Ashby, M L N; Bergin, E A; Chin, G; Erickson, N R; Goldsmith, P F; Harwit, M; Kleiner, S C; Koch, D G; Neufeld, D A; Patten, B M; Plume, R; Schieder, R; Stauffer, J R; Tolls, V; Wang, Z; Winnewisser, G; Zhang, Y F; Melnick, G J

    2000-01-01

    We present Submillimeter Wave Astronomy Satellite (SWAS) observations of the 1_{10}-1_{01} transition of ortho-water at 557 GHz toward 12 molecular cloud cores. The water emission was detected in NGC 7538, Rho Oph A, NGC 2024, CRL 2591, W3, W3(OH), Mon R2, and W33, and was not detected in TMC-1, L134N, and B335. We also present a small map of the water emission in S140. Observations of the H_2^{18}O line were obtained toward S140 and NGC 7538, but no emission was detected. The abundance of ortho-water relative to H_2 in the giant molecular cloud cores was found to vary between 6x10^{-10} and 1x10^{-8}. Five of the cloud cores in our sample have previous water detections; however, in all cases the emission is thought to arise from hot cores with small angular extents. The water abundance estimated for the hot core gas is at least 100 times larger than in the gas probed by SWAS. The most stringent upper limit on the ortho-water abundance in dark clouds is provided in TMC-1, where the 3-sigma upper limit on the ...

  1. Abundances In Very Metal Poor Dwarf Stars

    Cohen, J G; McWilliam, A; Shectman, S; Thompson, I; Wasserburg, G J; Ivans, I I; Dehn, M; Karlsson, T; Melendez, J; Cohen, Judith G.; Christlieb, Norbert; William, Andrew Mc; Shectman, Steve; Thompson, Ian; Ivans, Inese; Dehn, Matthias; Karlsson, Torgny

    2004-01-01

    We discuss the detailed composition of 28 extremely metal-poor dwarfs, 22 of which are from the Hamburg/ESO Survey, based on Keck Echelle spectra. Our sample has a median [Fe/H] of -2.7 dex, extends to -3.5 dex, and is somewhat less metal-poor than was expected from [Fe/H](HK,HES) determined from low resolution spectra. Our analysis supports the existence of a sharp decline in the distribution of halo stars with metallicity below [Fe/H] = -3.0 dex. So far no additional turnoff stars with [Fe/H]}<-3.5 have been identified in our follow up efforts. For the best observed elements between Mg and Ni, we find that the abundance ratios appear to have reached a plateau, i.e. [X/Fe] is approximately constant as a function of [Fe/H], except for Cr, Mn and Co, which show trends of abundance ratios varying with [Fe/H]. These abundance ratios at low metallicity correspond approximately to the yield expected from Type II SN with a narrow range in mass and explosion parameters; high mass Type II SN progenitors are requir...

  2. Abundances in Stars with Debris Disks

    Ritchey, Adam M; Stone, Myra; Wallerstein, George

    2013-01-01

    We present preliminary results of a detailed chemical abundance analysis for a sample of solar-type stars known to exhibit excess infrared emission associated with dusty debris disks. Our sample of 28 stars was selected based on results from the Formation and Evolution of Planetary Systems (FEPS) Spitzer Legacy Program, for the purpose of investigating whether the stellar atmospheres have been polluted with planetary material, which could indicate that the metallicity enhancement in stars with planets is due to metal-rich infall in the later stages of star and planet formation. The preliminary results presented here consist of precise abundances for 15 elements (C, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Fe, Co, and Ni) for half of the stars in our sample. We find that none of the stars investigated so far exhibit the expected trend of increasing elemental abundance with increasing condensation temperature, which would result from the stars having accreted planetary debris. Rather, the slopes of linear least...

  3. CH abundance gradient in TMC-1

    Suutarinen, Aleksi; Harju, Jorma; Heikkilä, Arto; Hotzel, Stephan; Juvela, Mika; Millar, Tom J; Walsh, Catherina; Wouterloot, Jan Gerard Amos

    2011-01-01

    We observed the 9-cm Lambda-doubling lines of CH along the dense filament of TMC-1. The CH column densities were compared with the total H2 column densities derived using the 2MASS NIR data and previously published SCUBA maps and with OH column densities derived using previous observations with Effelsberg. We also modelled the chemical evolution of TMC-1 adopting physical conditions typical of dark clouds using the UMIST Database for Astrochemistry gas-phase reaction network to aid the interpretation of the observed OH/CH abundance ratios. The CH column density has a clear peak in the vicinity of the cyanopolyyne maximum of TMC-1. The fractional CH abundance relative to H2 increases steadily from the northwestern end of the filament where it lies around 1.0e-8, to the southeast where it reaches a value of 2.0e-8. The OH and CH column densities are well correlated, and we obtained OH/CH abundance ratios of ~ 16 - 20. These values are clearly larger than what has been measured recently in diffuse interstellar g...

  4. Absolute Quantification of Endogenous Ras Isoform Abundance.

    Craig J Mageean

    Full Text Available Ras proteins are important signalling hubs situated near the top of networks controlling cell proliferation, differentiation and survival. Three almost identical isoforms, HRAS, KRAS and NRAS, are ubiquitously expressed yet have differing biological and oncogenic properties. In order to help understand the relative biological contributions of each isoform we have optimised a quantitative proteomics method for accurately measuring Ras isoform protein copy number per cell. The use of isotopic protein standards together with selected reaction monitoring for diagnostic peptides is sensitive, robust and suitable for application to sub-milligram quantities of lysates. We find that in a panel of isogenic SW48 colorectal cancer cells, endogenous Ras proteins are highly abundant with ≥260,000 total Ras protein copies per cell and the rank order of isoform abundance is KRAS>NRAS≥HRAS. A subset of oncogenic KRAS mutants exhibit increased total cellular Ras abundance and altered the ratio of mutant versus wild type KRAS protein. These data and methodology are significant because Ras protein copy number is required to parameterise models of signalling networks and informs interpretation of isoform-specific Ras functional data.

  5. Aerial survey estimates of fallow deer abundance

    Gogan, Peter J.; Gates, Natalie B.; Lubow, Bruce C.; Pettit, Suzanne

    2012-01-01

    Reliable estimates of the distribution and abundance of an ungulate species is essential prior to establishing and implementing a management program. We used ground surveys to determine distribution and ground and aerial surveys and individually marked deer to estimate the abundance of fallow deer (Dama dama) in north-coastal California. Fallow deer had limited distribution and heterogeneous densities. Estimated post-rut densities across 4 annual surveys ranged from a low of 1.4 (SE=0.2) deer/km2 to a high of 3.3 (se=0.5) deer/km2 in a low density stratum and from 49.0 (SE=8.3) deer/km2 to 111.6 deer/km2 in a high density stratum. Sightability was positively influenced by the presence of white color-phase deer in a group and group size, and varied between airial and ground-based observers and by density strata. Our findings underscore the utility of double-observer surveys and aerial surveys with individually marked deer, both incorporating covariates to model sightability, to estimate deer abundance.

  6. Principal Component Analysis on Chemical Abundances Spaces

    Ting, Y S; Kobayashi, C; De Silva, G M; Bland-Hawthorn, J

    2011-01-01

    [Shortened] In preparation for the HERMES chemical tagging survey of about a million Galactic FGK stars, we estimate the number of independent dimensions of the space defined by the stellar chemical element abundances [X/Fe]. [...] We explore abundances in several environments, including solar neighbourhood thin/thick disk stars, halo metal-poor stars, globular clusters, open clusters, the Large Magellanic Cloud and the Fornax dwarf spheroidal galaxy. [...] We find that, especially at low metallicity, the production of r-process elements is likely to be associated with the production of alpha-elements. This may support the core-collapse supernovae as the r-process site. We also verify the over-abundances of light s-process elements at low metallicity, and find that the relative contribution decreases at higher metallicity, which suggests that this lighter elements primary process may be associated with massive stars. [...] Our analysis reveals two types of core-collapse supernovae: one produces mainly alpha-e...

  7. Environmental factors shaping ungulate abundances in Poland.

    Borowik, Tomasz; Cornulier, Thomas; Jędrzejewska, Bogumiła

    2013-01-01

    Population densities of large herbivores are determined by the diverse effects of density-dependent and independent environmental factors. In this study, we used the official 1998-2003 inventory data on ungulate numbers from 462 forest districts and 23 national parks across Poland to determine the roles of various environmental factors in shaping country-wide spatial patterns of ungulate abundances. Spatially explicit generalized additive mixed models showed that different sets of environmental variables explained 39 to 50 % of the variation in red deer Cervus elaphus, wild boar Sus scrofa, and roe deer Capreolus capreolus abundances. For all of the studied species, low forest cover and the mean January temperature were the most important factors limiting their numbers. Woodland cover above 40-50 % held the highest densities for these species. Wild boar and roe deer were more numerous in deciduous or mixed woodlands within a matrix of arable land. Furthermore, we found significant positive effects of marshes and water bodies on wild boar abundances. A juxtaposition of obtained results with ongoing environmental changes (global warming, increase in forest cover) may indicate future growth in ungulate distributions and numbers. PMID:24244044

  8. Distribution and Abundance of Mars' Atmospheric Argon

    Sprague, A. L.; Boynton, W. V.; Kerry, K. E.; Nelli, Steven; Murphy, Jim; Reedy, R. C.; Metzger, A. E.; Hunten, D. M.; Janes, K. D.; Crombie, M. K.

    2005-01-01

    One and one half Mars years (MY 26 and 27) of atmospheric Argon measurements are described and studied in the context of understanding how Argon, a minor constituent of Mars atmosphere that does not condense at Mars temperatures, can be used to study martian circulation and dynamics. Argon data are from the 2001 Mars Odyssey Gamma Subsystem (GS) of the suite of three instruments comprising the Gamma Ray Spectrometer (GRS). A comprehensive data analysis including gamma-ray production and attenuation by the atmosphere is included. Of particular interest is the enhanced abundance of Ar over the observed Ar abundance at lower latitudes at south (up to a factor of 10) and north (up to a factor of 4) polar regions during winter. Calibration of the measurements to actual Ar abundance is possible because GS measurements cover the same latitude and season as measurements made by the gas chromatograph mass spectrometer (GCMS) on Viking Landers 1 and 2 (VL1 and VL2). [2].

  9. Relative Abundance Measurements in Plumes and Interplumes

    Guennou, Chloé; Savin, Daniel Wolf

    2015-01-01

    We present measurements of relative elemental abundances in plumes and interplumes. Plumes are bright, narrow structures in coronal holes that extend along open magnetic field lines far out into the corona. Previous work has found that in some coronal structures the abundances of elements with a low first ionization potential (FIP) 10 eV). We have used EIS spectroscopic observations made on 2007 March 13 and 14 over an ~24 hour period to characterize abundance variations in plumes and interplumes. To assess their elemental composition, we have used a differential emission measure (DEM) analysis, which accounts for the thermal structure of the observed plasma. We have used lines from ions of iron, silicon, and sulfur. From these we have estimated the ratio of the iron and silicon FIP bias relative to that for sulfur. From the results, we have created FIP-bias-ratio maps. We find that the FIP-bias ratio is sometimes higher in plumes than in interplumes and that this enhancement can be time dependent. These res...

  10. How selection structures species abundance distributions

    Magurran, Anne E.; Henderson, Peter A.

    2012-01-01

    How do species divide resources to produce the characteristic species abundance distributions seen in nature? One way to resolve this problem is to examine how the biomass (or capacity) of the spatial guilds that combine to produce an abundance distribution is allocated among species. Here we argue that selection on body size varies across guilds occupying spatially distinct habitats. Using an exceptionally well-characterized estuarine fish community, we show that biomass is concentrated in large bodied species in guilds where habitat structure provides protection from predators, but not in those guilds associated with open habitats and where safety in numbers is a mechanism for reducing predation risk. We further demonstrate that while there is temporal turnover in the abundances and identities of species that comprise these guilds, guild rank order is conserved across our 30-year time series. These results demonstrate that ecological communities are not randomly assembled but can be decomposed into guilds where capacity is predictably allocated among species. PMID:22787020

  11. Galactic abundance gradients from Cepheids : On the iron abundance gradient around 10-12 kpc

    Lemasle, B.; Francois, P.; Piersimoni, A.; Pedicelli, S.; Bono, G.; Laney, C. D.; Primas, F.; Romaniello, M.

    2008-01-01

    Context: Classical Cepheids can be adopted to trace the chemical evolution of the Galactic disk since their distances can be estimated with very high accuracy. Aims: Homogeneous iron abundance measurements for 33 Galactic Cepheids located in the outer disk together with accurate distance determinations based on near-infrared photometry are adopted to constrain the Galactic iron gradient beyond 10 kpc. Methods: Iron abundances were determined using high resolution Cepheid spectra collected wit...

  12. Species-abundance--seed-size patterns within a plant community affected by grazing disturbance.

    Wu, Gao-lin; Shang, Zhan-huan; Zhu, Yuan-jun; Ding, Lu-ming; Wang, Dong

    2015-04-01

    Seed size has been advanced as a key factor that influences the dynamics of plant communities, but there are few empirical or theoretical predictions of how community dynamics progress based on seed size patterns. Information on the abundance of adults, seedlings, soil seed banks, seed rains, and the seed mass of 96 species was collected in alpine meadows of the Qinghai-Tibetan Plateau (China), which had different levels of grazing disturbance. The relationships between seed-mass-abundance patterns for adults, seedlings, the soil seed bank, and seed rain in the plant community were evaluated using regression models. Results showed that grazing levels affected the relationship between seed size and abundance properties of adult species, seedlings, and the soil seed bank, suggesting that there is a shift in seed-size--species-abundance relationships as a response to the grazing gradient. Grazing had no effect on the pattern of seed-size-seed-rain-abundance at four grazing levels. Grazing also had little effect on the pattern of seed-size--species-abundance and pattern of seed-size--soil-seed-bank-abundance in meadows with no grazing, light grazing, and moderate grazing), but there was a significant negative effect in meadows with heavy grazing. Grazing had little effect on the pattern of seed-size--seedling-abundance with no grazing, but had significant negative effects with light, moderate, and heavy grazing, and the |r| values increased with grazing levels. This indicated that increasing grazing pressure enhanced the advantage of smaller-seeded species in terms of the abundances of adult species, seedlings, and soil seed banks, whereas only the light grazing level promoted the seed rain abundance of larger-seeded species in the plant communities. This study suggests that grazing disturbances are favorable for increasing the species abundance for smaller-seeded species but not for the larger-seeded species in an alpine meadow community. Hence, there is a clear

  13. Abundant Solar Nebula Solids in Comets

    Messenger, S.; Keller, L. P.; Nakamura-Messenger, K.; Nguyen, A. N.; Clemett, S.

    2016-01-01

    Comets have been proposed to consist of unprocessed interstellar materials together with a variable amount of thermally annealed interstellar grains. Recent studies of cometary solids in the laboratory have shown that comets instead consist of a wide range of materials from across the protoplanetary disk, in addition to a minor complement of interstellar materials. These advances were made possible by the return of direct samples of comet 81P/Wild 2 coma dust by the NASA Stardust mission and recent advances in microscale analytical techniques. Isotopic studies of 'cometary' chondritic porous interplanetary dust particles (CP-IDPs) and comet 81P/Wild 2 Stardust samples show that preserved interstellar materials are more abundant in comets than in any class of meteorite. Identified interstellar materials include sub-micron-sized presolar silicates, oxides, and SiC dust grains and some fraction of the organic material that binds the samples together. Presolar grain abundances reach 1 weight percentage in the most stardust-rich CP-IDPs, 50 times greater than in meteorites. Yet, order of magnitude variations in presolar grain abundances among CP-IDPs suggest cometary solids experienced significant variations in the degree of processing in the solar nebula. Comets contain a surprisingly high abundance of nebular solids formed or altered at high temperatures. Comet 81P/Wild 2 samples include 10-40 micron-sized, refractory Ca- Al-rich inclusion (CAI)-, chondrule-, and ameboid olivine aggregate (AOA)-like materials. The O isotopic compositions of these refractory materials are remarkably similar to their meteoritic counterparts, ranging from 5 percent enrichments in (sup 16) O to near-terrestrial values. Comet 81P/Wild 2 and CP-IDPs also contain abundant Mg-Fe crystalline and amorphous silicates whose O isotopic compositions are also consistent with Solar System origins. Unlike meteorites, that are dominated by locally-produced materials, comets appear to be composed of

  14. Niche partitioning and environmental factors affecting abundance of strepsirrhines in Angola.

    Bersacola, Elena; Svensson, Magdalena S; Bearder, Simon K

    2015-11-01

    The African nocturnal primates (galagos, pottos, and angwantibos: suborder Strepsirrhini) are the result of the first major primate radiation event in Africa, and are found in different primate communities spread across the entire sub-Saharan Africa. Thus, they represent an interesting group of taxa to investigate community strategies to avoid interspecific competition. Here, we present the result of the first study on nocturnal primate communities in western Angola. We aimed to identify habitat factors influencing strepsirrhine abundance, collect evidence of spatial niche segregation, and discuss possible indications of competitive exclusion in this region. We conducted nocturnal surveys at four study sites: Kumbira, Bimbe, Northern Scarp, and Calandula. At each encounter we recorded species, group size, height of animals above ground, and GPS location. We sampled vegetation using the point-centered quarter method and collected data on canopy cover, disturbance, and undergrowth density. We observed a total of five strepsirrhine species with varying community structures. We did not encounter Galagoides thomasi but we recorded a new species Galagoides sp. nov. 4. Levels of disturbance, canopy cover and undergrowth density were the habitat factors that most influenced variation in abundance of Galagoides demidovii and Perodicticus edwardsi, the latter also preferring the habitat with higher tree density. Vertical separation between sympatric strepsirrhines was strongest in Northern Scarp, where overall relative abundance was also highest. Competitive exclusion between G. thomasi and G. sp. nov. 4 may explain why the former was not present within the Angolan Escarpment sites. We observed coexistence between mainly allopatric Otolemur crassicaudatus and P. edwardsi in Kumbira, and of Galago moholi and G. demidovii in Calandula. Both unusual combinations showed some levels of spatial segregation. Habitat characteristics of the Escarpment region are likely to allow for

  15. [Beta-blockers usage in cardio-vascular diseases co-existing with COPD].

    Walczak, Dorota; Kowal, Aneta; Jankowska, Renata

    2012-12-01

    Chronic obstructive pulmonary disease (COPD) is one of the most frequent chronic diseases. Slightly reversable and progressive decrease in airflow through the airways is characteristic for the disease. It has been brought up last years that COPD course influences not only pulmonary system status but also many co-existing diseases in the eldery, especially cardio-vascular diseases, such as: ischaemic heart disease, hypertension, heart arrythmias, heart infarction. Wide usage and established position in the treatment of cardio-vascular diseases have the antagonists of beta-adrenergic receptors (beta-blockers). The aim of this work was the combination of the studies results quoted in the literature about the usage of beta-blockers in cardiovascular diseases co-existing with COPD. Conclusions. Nowadays there are no unambiguous recommendations for the usage of beta-blocker in patients with COPD and the decision about including them into treatment depends on the individually estimated risk of complications. PMID:23437704

  16. Variational approach to shape coexistence in sup 5 sup 6 Ni

    Petrovici, A; Faessler, A

    2001-01-01

    Results are presented concerning shape coexistence and neutron-proton correlations at low and high spins in the N=Z nucleus sup 5 sup 6 Ni obtained within the complex version of the Excited Vampir variational approach. The coexistence of small and moderately deformed oblate and prolate configurations, strongly mixed in some cases, may explain the irregularities observed for the yrast line, as well as the presence of other nonyrast states connected with them by E2 or Ml transitions. The first deformed band is well reproduced and predictions on the structure of next deformed bands are presented. These are the first microscopic calculations for sup 5 sup 6 Ni including in the model space the 0g sub 9 sub / sub 2 and 1d sub 5 sub / sub 2 spherical orbitals besides the full pf-shell. Contaminations due to the center of momentum motion are discussed and a rough method to eliminate them at least approximately is presented.

  17. Punctuated equilibrium and path dependency in coexistence: the Israeli health system and theories of change.

    Feder-Bubis, Paula; Chinitz, David

    2010-08-01

    Israel's enactment of national health insurance was clearly a breakthrough. However, other aspects of reform that were supposed to be implemented simultaneously were stymied, in particular, the conversion of government hospitals to independent trusts and removing the Ministry of Health from the direct provision of services such as mental health and long-term care. This article explores how punctuated equilibrium and path dependency coexist in the Israeli case. In doing so, it examines the relevance of concepts provided by various theories of social and institutional change. Aside from path dependency and punctuated equilibrium, we discuss other notions derived from related theories, such as political leadership and the role of ideas. Applying these theories to the Israeli case helps better understand the coexistence of punctuated equilibrium and path dependency. PMID:21057099

  18. Invasion, Coexistence, and Extinction Driven by Preemptive Competition and Sex Ratio

    Molnar, Ferenc; Caraco, Thomas; Korniss, Gyorgy

    2012-02-01

    We investigate competitive invasion in a simple population dynamics model, where females can differ genetically in the sex ratio of their offspring, and males can differ in mortality. Analyzing of the mean-field dynamics, we obtain conditions for ecological stability of a given sex-ratio allele for any mortality rate parameters. We also found that stable coexistence of the two alleles is possible, but only males can differ; one female phenotype is present. Our results show that the success of invasion is determined by the female birth sex ratio. A lower female ratio never excludes a larger female sex ratio; in case of coexistence, the surviving female phenotype always has the greater female sex ratio. Finally, we identified an interesting invasion-to-extinction scenario: successful invasion followed by extinction occurs when the invader initially propagates with the resident allele, but after excluding the resident, cannot survive on its own.

  19. Co-existence of classical and alternative activation programs in macrophages responding to Toxoplasma gondii.

    Patil, Veerupaxagouda; Zhao, Yanlin; Shah, Suhagi; Fox, Barbara A; Rommereim, Leah M; Bzik, David J; Yap, George S

    2014-02-01

    Pro-inflammatory M1 macrophages are critical for defense against intracellular pathogens while alternatively-activated M2 macrophages mediate tissue homeostasis and repair. Whether these distinct activation programs are mutually exclusive or can co-exist within the same cell is unclear. Here, we report the co-existence of these programs in Toxoplasma gondii-elicited inflammatory macrophages. This is independent of parasite expression of the virulence factor ROP16 and host cell expression of signal transducer and activator of transcription 6 (STAT6). Furthermore, this observation was recapitulated by IFN-γ and IL-4 treated bone marrow-derived macrophages in vitro. These results highlight the multi-functionality of macrophages as they respond to diverse microbial and endogenous stimuli. PMID:24083945

  20. Shape Coexistence and Band Termination in Doubly Magic Nucleus 40Ca

    DONG Bao-Guo; GUO Hong-Chao; SHI Yi-Jin

    2005-01-01

    Shape coexistence and band structure near yrast line of the Z = N doubly magic nucleus 40Ca have been investigated by the configuration-dependent cranked Nilsson-Strutinsky approach. The observed normal deformed and superdeformed bands are explained and the terminating states are confirmed by the calculations. The transition quadrupole moment Qt of the calculated superdeformed band is in good agreement with the observed one at high spin. There is shape coexistence within the same configuration. Possible normal deformed and superdeformed bands with rotation around the intermediate axis in several interesting configurations of40Ca are discussed. Possible favored superdeformed band terminations in 38Ca and 38Ar are predicted. The experimental results in 38Ar are discussed simply.

  1. Intrinsic advantages of Cheilomenes sexmaculata over two coexisting Coccinella species (Coleoptera:Coccinellidae)

    OMKAR; AHMADPERVEZ; GEETANJALIMISHRA; SHEFALISRIVASTAVA; SATYENDRAK.SINGH; AVANISHK.GUPTA

    2005-01-01

    Development, survival and reproductive performance of coexisting ladybird species, viz. Cheilomenes sexmaculata, Coccinella septempunctata, and Coccinella transversalis, of the tribe Coccinellini were studied and compared to assess their coexistence and ecological relationships. High values of life history parameters, viz. developmental rate,immature survival, fecundity, egg viability, reproductive rate and conversion of efficiency of ingested food were recorded for C. sexmaculata followed by C. transversalis and C.septempunctata suggesting that the former has intrinsic advantages over the latter two species. This could possibly counterbalance its disadvantages, like relatively smaller size and weight, thereby making it competitive. The developmental period increased with increase in body size. Exceptionally high fecundity after single mating has been recorded in C. sexmaculata. The egg viability, however, was lower than in both Coccinella species.

  2. Coexisting chaotic and multi-periodic dynamics in a model of cardiac alternans

    Skardal, Per Sebastian, E-mail: skardals@gmail.com [Departament d' Enginyeria Informàtica i Matemàtiques, Universitat Rovira i Virgili, 43007 Tarragona (Spain); Restrepo, Juan G., E-mail: juanga@colorado.edu [Department of Applied Mathematics, University of Colorado, Boulder, Colorado 80309 (United States)

    2014-12-15

    The spatiotemporal dynamics of cardiac tissue is an active area of research for biologists, physicists, and mathematicians. Of particular interest is the study of period-doubling bifurcations and chaos due to their link with cardiac arrhythmogenesis. In this paper, we study the spatiotemporal dynamics of a recently developed model for calcium-driven alternans in a one dimensional cable of tissue. In particular, we observe in the cable coexistence of regions with chaotic and multi-periodic dynamics over wide ranges of parameters. We study these dynamics using global and local Lyapunov exponents and spatial trajectory correlations. Interestingly, near nodes—or phase reversals—low-periodic dynamics prevail, while away from the nodes, the dynamics tend to be higher-periodic and eventually chaotic. Finally, we show that similar coexisting multi-periodic and chaotic dynamics can also be observed in a detailed ionic model.

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

    Mitarai, Namiko; Heinsalu, Els; Sneppen, Kim

    2014-01-01

    Speciation, diversification, and competition between species challenge the stability of complex ecosystems. Laboratory experiments often focus on one or two species competing under conditions where they may grow exponentially. Field studies, in contrast, emphasize multi-species communities...... characterized by many types of ecological interactions. A general problem is to understand conditions that support a dynamically maintained coexistence of many species in an ecosystem over a long time span. In the present paper we propose a lattice model of multiple competing and evolving sessile species. When...... allowing the interspecies interactions to mutate, we obtain coexistence of many species in a complex ecosystem, provided that there is a cost for each interaction. The diversity reached by the model incorporating speciation is found to be substantially higher than in the case when entirely new species...

  4. A rare case of breast carcinoma co-existing with axillary mantle cell lymphoma

    Scally John

    2003-12-01

    Full Text Available Abstract Background Mantle cell lymphoma (MCL is a rare variety of non-Hodgkin's lymphoma which originates from CD5+ B-cell population in the mantle zones of lymphoid follicles. Coexistence of such tumours in the axillary lymph nodes with invasive breast cancers without prior history of adjuvant chemotherapy or radiotherapy has not been previously reported in literature. Case report We report a rare case of breast cancer co-existing with stage I mantle cell lymphoma of the ipsilateral axillary lymph node detected fortuitously by population screening. Conclusion Though some studies have tried to prove breast carcinomas and lymphomas to share a common molecular or viral link, more research needs to be done to establish whether such a link truly exists.

  5. High-resolution synchrotron powder diffraction analysis of ordinary Portland cements: Phase coexistence of alite

    The mineralogical composition of four commercial and NIST RM-8488 Portland clinkers have been analysed by Rietveld methodology using high-resolution synchrotron X-ray powder diffraction data. Alite phase coexistence has been observed in four patterns. White Portland clinkers show a single alite or a very small amount of a second alite with smaller volume due to higher magnesium content. Grey Portland clinkers show a much pronounced alite phase coexistence which has been related to higher magnesium contents. Details about these analyses are given. Furthermore, the full mineralogical composition (including the non-diffracting content) has been determined from the overestimation of the added standard, α-Al2O3, in the Rietveld analyses. White clinkers contain ∼15 wt.% of non-diffracting content while this fraction is much smaller in grey clinkers, ∼7 wt.%

  6. High-resolution synchrotron powder diffraction analysis of ordinary Portland cements: Phase coexistence of alite

    Torre, Angeles G. de la [Departamento de Quimica Inorganica, Cristalografia y Mineralogia, Universidad de Malaga, 29071 Malaga (Spain); Losilla, Enrique R. [Departamento de Quimica Inorganica, Cristalografia y Mineralogia, Universidad de Malaga, 29071 Malaga (Spain); Cabeza, Aurelio [Departamento de Quimica Inorganica, Cristalografia y Mineralogia, Universidad de Malaga, 29071 Malaga (Spain); Aranda, Miguel A.G. [Departamento de Quimica Inorganica, Cristalografia y Mineralogia, Universidad de Malaga, 29071 Malaga (Spain)]. E-mail: g_aranda@uma.es

    2005-08-15

    The mineralogical composition of four commercial and NIST RM-8488 Portland clinkers have been analysed by Rietveld methodology using high-resolution synchrotron X-ray powder diffraction data. Alite phase coexistence has been observed in four patterns. White Portland clinkers show a single alite or a very small amount of a second alite with smaller volume due to higher magnesium content. Grey Portland clinkers show a much pronounced alite phase coexistence which has been related to higher magnesium contents. Details about these analyses are given. Furthermore, the full mineralogical composition (including the non-diffracting content) has been determined from the overestimation of the added standard, {alpha}-Al{sub 2}O{sub 3}, in the Rietveld analyses. White clinkers contain {approx}15 wt.% of non-diffracting content while this fraction is much smaller in grey clinkers, {approx}7 wt.%.

  7. Competition and possible coexistence of flux and RVB phases in the t-J model

    The competition and possible coexistence of the flux phase and pairing states are considered within the slave boson approach. In addition to the gauge field coupling holons and spinons, a statistical gauge field is introduced to account for the hard-core nature of holons. Using the equivalence of π-uniform and -staggered fluxes we show the possibility of reducing the staggered flux and guarantee the commensurability condition of the uniform flux for holons at the same time. For certain dopings the frustration of the spinon gauge field to holon motion can be compensated by holon's own statistical gauge field. In contrary to earlier conclusions of other authors, we find that the flux phase coexists with the RVB states below a critical doping concentration δc, beyond which the d-wave RVB state takes over. (author). 20 refs, 4 figs

  8. Pancreatic insulinoma co-existing with gastric GIST in the absence of neurofibromatosis-1

    O'Sullivan Brendan

    2009-02-01

    Full Text Available Abstract Background Gastrointestinal stromal tumours (GIST frequently occur in patients with neurofibromatosis type 1 (NF-1. It has been reported that GIST may co-exist with pancreatic endocrine tumors but this has only been in association with NF-1. Case presentation A 76 year old woman presented with a 12 month history of hypoglycaemia symptoms. Abdominal CT scan demonstrated a 13 mm insulinoma localized in the tail of her pancreas. She was commenced on diazoxide and later underwent surgery for enucleation of insulinoma when a small ( Conclusion This is the first case report of a pancreatic insulinoma co-existing with a GIST in a patient without NF-1. In addition, we make the first report of rapidly growing cystic GIST recurrence following resection of a primary GIST tumour.

  9. Molecular Density Functional Theory for water with liquid-gas coexistence and correct pressure

    Jeanmairet, Guillaume; Sergiievskyi, Volodymyr; Borgis, Daniel

    2015-01-01

    The solvation of hydrophobic solutes in water is special because liquid and gas are almost at coexistence. In the common hypernetted chain approximation to integral equations, or equivalently in the homogenous reference fluid of molecular density functional theory, coexistence is not taken into account. Hydration structures and energies of nanometer-scale hydrophobic solutes are thus incorrect. In this article, we propose a bridge functional that corrects this thermodynamic inconsistency by introducing a metastable gas phase for the homogeneous solvent. We show how this can be done by a third order expansion of the functional around the bulk liquid density that imposes the right pressure and the correct second order derivatives. Although this theory is not limited to water, we apply it to study hydrophobic solvation in water at room temperature and pressure and compare the results to all-atom simulations. With this correction, molecular density functional theory gives, at a modest computational cost, quantita...

  10. Twin pregnancy with complete hydatidiform mole and coexisting live fetus complicated with HELLP syndrome

    Deepti Sharma

    2013-02-01

    Full Text Available Hydatidiform mole with a coexisting live twin is an extremely rare event. It poses a great challenge for the obstetrician to decide for or against continuation of such a pregnancy, especially if the conception is after infertility treatment. Continuation carries risk of medical complications and persistent trophoblastic disease. We report a case of 22 year old primigravida, with complete hydatidiform mole coexisting with a live fetus. Patient had conceived in her fourth cycle of ovulation induction and wanted to continue pregnancy. She developed severe preeclampsia and HELLP syndrome. In this case report we highlight the importance of intense antenatal monitoring and the possibility of sudden deterioration of maternal condition forcing immediate termination. [Int J Reprod Contracept Obstet Gynecol 2013; 2(1.000: 92-94

  11. Selective directed self-assembly of coexisting morphologies using block copolymer blends

    Stein, A.; Wright, G.; Yager, K. G.; Doerk, G. S.; Black, C. T.

    2016-08-01

    Directed self-assembly (DSA) of block copolymers is an emergent technique for nano-lithography, but is limited in the range of structures possible in a single fabrication step. Here we expand on traditional DSA chemical patterning. A blend of lamellar- and cylinder-forming block copolymers assembles on specially designed surface chemical line gratings, leading to the simultaneous formation of coexisting ordered morphologies in separate areas of the substrate. The competing energetics of polymer chain distortions and chemical mismatch with the substrate grating bias the system towards either line/space or dot array patterns, depending on the pitch and linewidth of the prepattern. This is in contrast to the typical DSA, wherein assembly of a single-component block copolymer on chemical templates generates patterns of either lines/spaces (lamellar) or hexagonal dot arrays (cylinders). In our approach, the chemical template encodes desired local spatial arrangements of coexisting design motifs, self-assembled from a single, sophisticated resist.

  12. Coexistence Theory of Slag Structure and Its Application to Calculation of Oxidizing Capability of Slag Melts

    2003-01-01

    The coexistence theory of slag structure and it's application to calculation of the oxidizing capabilities of slag melts is described. It is shown that the law of mass action can be widely applied to the calculation of oxidizing capabilities of slag melts in combination with the coexistence theory of slag structure.For slag melts containing basic oxides FeO and MnO, their oxidizing capabilities can be expressed by NFetO=NFeO+6NFe2O3, while for slag melts containing basic oxides CaO, MgO, etc., in addition to FeO and MnO, their oxidizing capabilities can be given as NFetO=NFeO+6NFe2O3+8NFe3O4.

  13. Influences of different control periods and coexistence with weed in eucalyptus

    Eduardo Kneipp Londero

    2012-09-01

    Full Text Available This work studied the periods of control and coexistence of weeds with eucalyptus culture. The experiment was led in Candiota, RS, in the period from January to December, 2006. The treatments consisted of different control times and coexistence of the culture, these periods were divided in two groups; one was to determine the Period Previous to the Interference (PPI and the other to define the Total Period of Prevention of the Interference (TPFI. In the two groups the tested periods were: 00, 28, 56, 84, 112, 140, 168, 210, 252, 294 and 336 days. The young trees of eucalyptus were susceptible to weed, presenting a period previous to the interference of 56 days. In order to guarantee its largest production, the total period of prevention of the interference was 140 days and the period previous to the interference was of 56 days.

  14. Critical currents and superconductivity ferromagnetism coexistence in high-Tc oxides

    Khene, Samir

    2016-01-01

    The book comprises six chapters which deal with the critical currents and the ferromagnetism-superconductivity coexistence in high-Tc oxides. It begins by gathering key data for superconducting state and the fundamental properties of the conventional superconductors, followed by a recap of the basic theories of superconductivity. It then discusses the differences introduced by the structural anisotropy on the Ginzburg-Landau approach and the Lawrence-Doniach model before addressing the dynamics of vortices and the ferromagnetism-superconductivity coexistence in high-Tc oxides, and provides an outline of the pinning phenomena of vortices in these materials, in particular the pinning of vortices by the spins. It elucidates the methods to improve the properties of superconducting materials for industrial applications. This optimization aims at obtaining critical temperatures and densities of critical currents at the maximum level possible. Whereas the primary objective is the basic mechanisms pushing the superco...

  15. Co-existing institutional logics and agency among top-level public servants

    Bjerregaard, Toke

    2011-01-01

    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......While institutional organization research to some extent has neglected the micro agency of organization members, parts of the strategy-as-practice research have tended to bracket off wider societal environments shaping the practices-in-use of top-level strategy practitioners. This article attempts...... 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...

  16. The Coexistence of Tuberculous Lymphadenitis with o ral Squamous Cell Carcinoma: Review of Four Cases

    Aakruti Agrawal

    2016-01-01

    Full Text Available The coincident occurrence of tuberculous lymphadenitis, the form of extrapulmonary tuberculosis and oral squamous cell carcinoma (OSCC, is unusual. Tuberculous lymphadenitis is one of the common causes of lymphadenopathy. The diag- nosis and treatment of OSCC in a patient with coexistent disease of tuberculous lymphadenitis assumes importance as it can prevent high mortality in patients with disease of OSCC. Regional lymph node enlargement in squamous cell carcinoma patient is not always caused by metastasis. We present here four case reports as an example of tuberculous lymphadenitis coexisting with squamous cell carcinoma of the oral cavity. Accurate diagnosis has helped in down-staging carcinoma of the oral cavity, and thereby helped in deciding the treatment planning. This also aids in identifying the curable disease.

  17. Vapor-like liquid coexistence densities affect the extension of the critical point's influence zone

    Rivera, Jose Luis; Guerra-Gonzalez, Roberto

    2015-01-01

    The critical point affects the coexistence behavior of the vapor-liquid equilibrium densities. The length of the critical influence zone is under debate because for some properties, like shear viscosity, the extension is only a few degrees, while for others, such as the density order parameter, the critical influence zone range covers up to hundreds of degrees below the critical temperature. Here we show that for a simple molecular potential of ethane, the critical influence zone covers a wide zone of tens of degrees (below the critical temperature) down to a transition temperature, at which the apparent critical influence zone vanishes and the transition temperature can be predicted through a pressure analysis of the coexisting bulk liquid phase. The liquid phases within the apparent critical influence zone show low densities, making them behave internally like their corresponding vapor phases. Therefore, the experimentally observed wide extension of the critical influence zone is due to a vapor-like effect ...

  18. The Coexistence of Dual Form of Malnutrition in A Sample of Rural Malaysia

    A N Ihab; Rohana, A. J.; W M Wan Manan; W N Wan Suriati; Zalilah, M. S.; A.M.Rusli

    2013-01-01

    Background: The coexistence of under and over nutrition might be influenced by a marked shift in dietary and lifestyle practices of people in developing countries. This study aims to identify factors associated with the occurrence of dual form of malnutrition in the same households in a rural district in Peninsular Malaysia. Methods: A cross sectional study was conducted on a 223 mother-child pairs based on several inclusion criteria such as; non-pregnant, non lactating mothers and having...

  19. Shape coexistence in the neutron-deficient Pt isotopes in a configuration mixing IBM

    The recently proposed matrix-coherent state approach for configuration mixing IBM is used to describe the evolving geometry of the neutron deficient Pt isotopes. It is found that the Potential Energy Surface (PES) of the Platinum isotopes evolves, when the number of neutrons decreases, from spherical to oblate and then to prolate shapes, in agreement with experimental measurements. Oblate-Prolate shape coexistence is observed in 194,192Pt isotopes

  20. Two coexisting tank bromeliads host distinct algal communities on a tropical inselberg

    Carrias, J. F.; Cereghino, R.; Brouard, O.; Pelozuelo, L.; Dejean, A; Coute, A.; Corbara, B.; Leroy, Céline

    2014-01-01

    The tank bromeliads Aechmea aquilega (Salisb.) and Catopsis berteroniana (Schultes f.) coexist on a sun-exposed Neotropical inselberg in French Guiana, where they permit conspicuous freshwater pools to form that differ in size, complexity and detritus content. We sampled the algal communities (both eukaryotic and cyanobacterial taxa, including colourless forms) inhabiting either A. aquilega (n = 31) or C. berteroniana (n = 30) and examined differences in community composition and biomass patt...

  1. Genetically modified and non-genetically modified food supply chains : co-existence and traceability

    Bertheau, Yves

    2013-01-01

    In the European Union nations, and other countries including Japan, Australia and Malaysia, it is a legal requirement that food products containing genetically modified organism (GMO) materials are labelled as such in order that customers may make informed purchasing decisions. For manufacturers and consumers to be confident about these assertions, systems must be in place along the entire food chain which support the co-existence of GM and non GM materials whilst maintaining a strict segrega...

  2. Observation of Coexisting Dissipative Solitons in a Mode-Locked Fiber Laser.

    Bao, Chengying; Chang, Wonkeun; Yang, Changxi; Akhmediev, Nail; Cundiff, Steven T

    2015-12-18

    We show, experimentally and numerically, that a mode-locked fiber laser can operate in a regime where two dissipative soliton solutions coexist and the laser will periodically switch between the solutions. The two dissipative solitons differ in their pulse energy and spectrum. The switching can be controlled by an external perturbation and triggered even when switching does not occur spontaneously. Numerical simulations unveil the importance of the double-minima loss spectrum and nonlinear gain to the switching dynamics. PMID:26722922

  3. A MATHEMATICAL PROGRAMMING MODEL FOR THE COEXISTENCE OF COMPETITIONS AND COOPERATIONS PROBLEMS

    MENG Zhiqing; HU Qiying; DANG Changyan

    2005-01-01

    We study in. This paper a mathematical programming model for the coexistence of competitions and cooperations problems. We introduce a new solution concept,s-optimal solution for the problem, which always exists under compact and continuous conditions. It is shown that an s-optimal solution can be obtained by solving a nonlinear programming problem. Some examples are given to explain how to compute an s-optimal solution.

  4. Self-diffusion and structural properties of confined fluids in dynamic coexistence

    Self-diffusion and radial distribution functions are studied in a strongly confined Lennard-Jones fluid. Surprisingly, in the solid–liquid phase transition region, where the system exhibits dynamic coexistence, the self-diffusion constants are shown to present up to three-fold variations from solid to liquid phases at fixed temperature, while the radial distribution function corresponding to both the liquid and the solid phases are essentially indistinguishable. (paper)

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

    Magård, Else

    2002-01-01

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

  6. The Coexistence of GM and non-GM Crops and the Role of Consumer Preferences

    Merel, Pierre R.; Carter, Colin A.

    2005-01-01

    Crop coexistence is now at the core of the debate on GM technology in Europe. New regulations are being designed in the E.U. in order to "correct" potential production externalities and ensure that conventional and organic production will remain a profitable alternative for farmers. We use a simple Mussa-Rosen type model of preferences to capture the effects of introducing a cost-saving GM crop on incumbent crops, taking explicitly into account consumers' distaste for GM food products. Using ...

  7. Co-existence with GM crops: grasses, clover and fodder beet

    Jørgensen, R. B.; Løjtnant, C.; Andersen, N.S.; Andersen, B.A.

    2007-01-01

    Co-existence with GM crops: grasses, clover and fodder beet In 2006 the global cultivation of genetically modified crops increased with 13% and reached 102 million hectares. The GM crops cultivated are mainly soybean, maize, cotton and oilseed rape, but other modified crops are appearing, e.g. in 2006 herbicide tolerant alfalfa was commercialized in US. Also in Europe, GM crop cultivation is increasing with the largest areas in Rumania and Spain followed by Portugal, France, Germany, Czec...

  8. Organic matter dynamics control plant species coexistence in a tropical peat swamp forest

    Shimamura, Tetsuya; Momose, Kuniyasu

    2005-01-01

    We studied the relationship between the coexistence of tree species and the dynamics of organic matter in forests. A tropical peat swamp forest was selected as a model ecosystem, where abiotic factors, such as geological topography or parent rock types, are homogeneous and only biological processes create habitat heterogeneity. The temporal or spatial variation of the ground elevation of peat soils is mainly caused by changes in the balance between organic matter inputs to soils and decomposi...

  9. Team building with information system departments: a hospital librarian's experience in coexisting, collaborating, and cooperating.

    Grosman, J; Larson, B.

    1996-01-01

    Hospital librarians and information systems (IS) staff regard themselves as information professionals and have coexisted in the same institutions for many years. While hospital librarians have increased their computer literacy, IS staff have begun to recognize the value of knowledge-based information as an IS resource. Parallel growth and mutual interest have resulted in increased opportunities for information professionals to share skills and network for mutual advantage. Creating positive r...

  10. Experimental Investigation of Coexistence Interference on Multi-Radio 802.11 Platforms

    Farshad, Arsham; Marina, Mahesh; García, Francisco J.

    2012-01-01

    We study coexistence interference that arises between multiple collocated radio interfaces on 802.11 based multi-radio platforms used for mesh networks. We show that such interference can be so severe that it prevents concurrent successful operation of collocated interfaces even when they use channels from widely different frequency bands. We propose the use of antenna polarization to mitigate such interference and experimentally study its benefit in both multi-band and single band configurat...

  11. Pharmaceutical and Industrial Traits in Genetically Modified Crops: Co-Existence with Conventional Agriculture

    Moschini, GianCarlo

    2006-01-01

    This paper discusses the implications of using genetically modified crops to biomanufacture pharmaceuticals and industrial compounds from the perspective of their co-existence with conventional agriculture. Such plant-made pharmaceuticals and plant-made industrial products rely on exciting scientific and technological breakthroughs and promise new opportunities for the agricultural sector, but they also entail novel risks. The management of the externalities and of the possible unintended eco...

  12. Unusual case of bancroftian filariasis co-existing with chronic myeloid leukemia

    Mallika Kinger; Preeti Rihal Chakrabarti; Surabhi Sharma; Priyanka Kiyawat

    2014-01-01

    Filariasis, a tropical parasite infection, is a common public health problem in the Indian sub-continent. Occurrence of filariasis with chronic myeloid leukemia (CML) is unusual though there are case reports of leishmaniasis, malaria, and other vector-borne diseases seen in association with leukemias. Filariasis co-existing with CML has not been documented to the best of our knowledge and hence definitely needs a space in literature. We report an incidental finding of bancroftian filariasis i...

  13. Phenomenological approach to the coexistence of planar antiferromagnetism with high Tc type II superconductivity

    A phenomenological study in d-spatial dimensions is presented for the coexistence of planar antiferromagnetism and type II superconductivity. In this approach critical temperatures in the range 30-100 K arise due to the proposed coupling of magnons and conduction electron-pairs. We discuss some remarkable features of oxide ceramics, including a longer London penetration depth, shorter coherence length, lower Hcl, higher Hc2, large current densities, and large pinning force. (author). 45 refs, 3 figs

  14. Speciation, Diversification, and Coexistence of Sessile Species That Compete for Space

    Namiko Mitarai; Els Heinsalu; Kim Sneppen

    2014-01-01

    Speciation, diversification, and competition between species challenge the stability of complex ecosystems. Laboratory experiments often focus on one or two species competing under conditions where they may grow exponentially. Field studies, in contrast, emphasize multi-species communities characterized by many types of ecological interactions. A general problem is to understand conditions that support a dynamically maintained coexistence of many species in an ecosystem over a long time span....

  15. Collapse and coexistence for a molecular braid with an attractive interaction component subject to mechanical forces

    Dual mechanical braiding experiments provide a useful tool with which to investigate the nature of interactions between rod-like molecules, for instance actin and DNA. In conditions close to molecular condensation, one would expect an appearance of a local minimum in the interaction potential between the two molecules. We investigate this situation, introducing an attractive component into the interaction potential, using a model developed for describing such experiments. We consider both attractive interactions that do not depend on molecular structure and those which depend on a DNA-like helix structure. In braiding experiments, an attractive term may lead to certain effects. A local minimum may cause molecules to collapse from a loosely braided configuration into a tight one, occurring at a critical value of the moment applied about the axis of the braid. For a fixed number of braid pitches, this may lead to coexistence between the two braiding states, tight and loose. Coexistence implies certain proportions of the braid are in each state, their relative size depending on the number of braid pitches. This manifests itself as a linear dependence in numerically calculated quantities as functions of the number of braid pitches. Also, in the collapsed state, the braid radius stays roughly constant. Furthermore, if the attractive interaction is helix dependent, the left-right handed braid symmetry is broken. For a DNA like charge distribution, using the Kornyshev–Leikin interaction model, our results suggest that significant braid collapse and coexistence only occurs for left handed braids. Regardless of the interaction model, the study highlights the possible qualitative physics of braid collapse and coexistence; and the role helix specific forces might play, if important. The model could be used to connect other microscopic theories of interaction with braiding experiments. (paper)

  16. From income to capital breeding: when diversified strategies sustain species coexistence.

    Pierre-François Pélisson

    Full Text Available There is empirical evidence of many diversified ways for energy to be acquired and allocated to reproduction, notably with strategies ranging from strict income breeding (females fueling their gametes with energy gained concomitantly during reproduction to strict capital breeding (females storing nutrients prior reproduction. Until now, the question of whether diversification of these strategies might impact the way communities are organized has not been considered. Here, we suggest that diversified resource allocation strategies among competing species may contribute to their coexistence. We examined this hypothesis by focusing on communities composed of four phytophagous insect species that coexist and compete for egg-laying sites. From wild-caught females, we determined precisely the breeding period of each species and we described their resource acquisition and allocation to reproduction dynamics. We quantified in each species the total amount of larval energy stored by newly-emerging females and then monitored the total energy budget of females caught in the field before and throughout their breeding period. We found that the four sibling weevil species are markedly segregated along the income-capital-breeding continuum, which is correlated with clear time partitioning in their laying activity. Our results suggest that diversified resource allocation strategies might contribute to time partitioning of plant resources exploitation and thus indirectly to their coexistence. This work should further encourage studies examining the extent to which competitive coexistence might be affected by diversification of income-capital breeding strategies together with the intensity of interspecific competition, and considering the divergent evolution of these strategies.

  17. Coexistent axillary hydatid disease and tuberculosis: Case report of an extremely rare occurrence

    Shalini Bahadur; Mukta Pujani; Sujata Jetley; Mohammad Jaseem Hassan; Shaan Khetrapal; Musharraf Husain

    2014-01-01

    Tuberculous infection is highly prevalent in India, however, hydatid disease is relatively uncommon. Frequent sites of predilection of hydatid disease are the liver and lungs. Other unusual sites of infliction are the peritoneum, thyroid, breast, pancreas, and mediastinum. Hydatid disease in the axilla is quite uncommon. We hereby report a case of coexistent axillary hydatid disease with tuberculous lymphadenitis. To the best of our knowledge, even after extensive search of the literature we ...

  18. Pulse shape of the self quenching streamer counter in the coexistence region

    The pulse shape of the electrical signal out of the counter operating in the self-quenching streamer (SQS) mode is obtained and the time correlation between the primary avalanche and the SQS avalanche is measured and studied. The results yield more information in the coexistence region about the time jitters in the process of the SQS avalanche than that shown in our last paper. (orig.)

  19. Coexistence of two dengue virus serotypes and forecasting for Madeira island

    Rocha, Filipa Portugal; Rodrigues, Helena Sofia; Monteiro, M. Teresa T.; Torres, Delfim F. M.

    2015-01-01

    The first outbreak of dengue occurred in Madeira Island on 2012, featuring one virus serotype. Aedes aegypti was the vector of the disease and it is unlikely that it will be eliminated from the island. Therefore, a new outbreak of dengue fever can occur and, if it happens, risk to the population increases if two serotypes coexist. In this paper, mathematical modeling and numerical simulations are carried out to forecast what may happen in Madeira Island in such scenario.

  20. Two adolescent patients with coexistent Graves' disease and Moyamoya disease in Korea

    Cheon, Chong Kun; Kim, Su Yung; Yoo, Jae-Ho

    2014-01-01

    Moyamoya disease is a cerebrovascular condition that results in the narrowing of the vessels of the circle of Willis and collateral vessel formation at the base of the brain. Although relationships between Graves' disease and cerebrovascular accidents in Moyamoya disease are obscure, the coexistence of the two diseases is noteworthy. Moyamoya disease has been rarely reported in adolescent patients with thyrotoxicosis. Recently, we encountered two adolescent Korean patients with Moyamoya disea...