993 resultados para Inter-genotype competition


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El concepto de efectividad en Redes Inter-organizacionales se ha investigado poco a pesar de la gran importancia en el desarrollo y sostenibilidad de la red. Es muy importante entender este concepto ya que cuando hablamos de Red, nos referimos a un grupo de más de tres organizaciones que trabajan juntas para alcanzar un objetivo colectivo que beneficia a cada miembro de la red. Esto nos demuestra la importancia de evaluar y analizar este fenómeno “Red Inter-organizacional” de forma más detallada para poder analizar que estructura, formas de gobierno, relaciones entre los miembros y entre otros factores, influyen en la efectividad y perdurabilidad de la Red Inter-organizacional. Esta investigación se desarrolla con el fin de plantear una aproximación al concepto de medición de la efectividad en Redes Inter-organizacionales. El trabajo se centrara en la recopilación de información y en la investigación documental, la cual se realizará por fases para brindarle al lector una mayor claridad y entendimiento sobre qué es Red, Red Inter-Organizacional, Efectividad. Y para finalizar se estudiara Efectividad en una Red Inter-organizacional.

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We study competition in two sided markets with common network externality rather than with the standard inter-group e¤ects. This type of externality occurs when both groups bene t, possibly with di¤erent intensities, from an increase in the size of one group and from a decrease in the size of the other. We explain why common externality is relevant for the health and education sectors. We focus on the symmetric equilibrium and show that when the externality itself satis es an homogeneity condition then platforms pro ts and price structure have some speci c properties. Our results reveal how the rents coming from network externalities are shifted by platforms from one side to other, according to the homogeneity degree. In the speci c but realistic case where the common network externality is homogeneous of degree zero, platform s pro t do not depend on the intensity of the (common) network externality. This is in sharp contrast to conventional results stating that the presence of network externalities in a two-sided market structure increases the intensity of competition when the externality is positive (and decreases it when the externality is negative). Prices are a¤ected but in such a way that platforms only transfer rents from consumers to providers.

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Four experiments conducted over three seasons (2002–05) at the Crops Research Unit, University of Reading, investigated effects of canopy management of autumn sown oilseed rape (Brassica napus L. ssp. oleifera var. biennis (DC.) Metzg.) on competition with grass weeds. Emphasis was placed on the effect of the crop on the weeds. Rape canopy size was manipulated using sowing date, seed rate and the application of autumn fertilizer. Lolium multiflorum Lam., L.rboucheanum Kunth and Alopecurus myosuroides Huds. were sown as indicative grass weeds. The effects of sowing date, seed rate and autumn nitrogen on crop competitive ability were correlated with rape biomass and fractional interception of photosynthetically active radiation (PAR) by the rape floral layer, to the extent that by spring there was good evidence of crop: weed replacement. An increase in seed rate up to the highest plant densities tested increased both rape biomass and competitiveness, e.g. in 2002/3, L. multiflorum head density was reduced from 539 to 245 heads/m2 and spikelet density from 13 170 to 5960 spikelets/m2 when rape plant density was increased from 16 to 81 plants/m2. Spikelets/head of Lolium spp. was little affected by rape seed rate, but the length of heads of A. myosuroides was reduced by 9%when plant density was increased from 29–51 plants/m2. Autumn nitrogen increased rape biomass and reduced L. multiflorum head density (415 and 336 heads/m2 without and with autumn nitrogen, respectively) and spikelet density (9990 and 8220 spikelets/m2 without and with autumn nitrogen, respectively). The number of spikelets/head was not significantly affected by autumn nitrogen. Early sowing could increase biomass and competitiveness, but poor crop establishment sometimes overrode the effect. Where crop and weed establishment was similar for both sowing dates, a 2-week delay (i.e. early September to mid-September) increased L. multiflorum head density from 226 to 633 heads/m2 and spikelet density from 5780 to 15 060 spikelets/m2.

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Individual fitness and the structure of marine communities are strongly affected by spatial competition. Among the most common space holders are the colonial ascidians, which have the ability to monopolize large areas of hard substrate, overgrowing most other competitors. The effects of competition on colony growth and on gonad production of the ascidian Didemnum perlucidum were studied in southeastern Brazil by experimentally removing surrounding competitors. Colonies of D, perlucidum competing for space exhibited a growth rate 9 times less than that of colonies that were competitor free. Among the colonies subject to competition, growth rates were unrelated to the percentage of colony border that was free of competitors. However, the identity of the competitor was important in the outcome of border contacts. At the beginning of the experiment, most border encounters of D. perlucidum were with solitary organisms, which in most cases were overgrown. These were progressively replaced by colonial ascidians and bryozoans, resulting mostly in stand-off interactions. Besides reducing asexual growth, spatial competition also affected female gonad production. Colonies free of competitors had a significantly higher proportion of zooids with ovaries. Thus, our findings show that spatial competition reduces both ascidian colony size and gonad production.

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Dengue virus type 4 (DENV-4) circulates in tropical and subtropical countries from Asia and the Americas. Despite the importance of dengue virus distribution, little is known about the worldwide viral spread. Following a Bayesian phylogenetic approach we inferred the evolutionary history of 310 isolates sampled from 37 countries during the time period 1956-2008 and the spreading dynamics for genotypes I and II. The region (tropical rainforest biome) comprised by Malaysia-Thailand was the most likely ancestral area from which the serotype has originated and spread. Interestingly, cross-correlation analysis on demographic time series with the Asian sequences showed a statistically significant negative correlation that could be suggestive of competition among genotypes within the same serotype. (C) 2011 Elsevier B.V. All rights reserved.

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We determined the inter-day variability in elite-standard women's artistic gymnastics competition scores. National (50 gymnasts for up to three days) and Olympic (24 gymnasts for up to five days) competition scores published in the public domain (‘Giant poster pull-out’, 2010; Gymnastics Australia, 2008) were evaluated using three statistical measures. Analyses of the inter-day differences in the mean scores as a percentage (MDiff%), coefficient of variation percentages for the mean score across both days (CV%), and Pearson correlation coefficients for the inter-day score (r) were interpreted using thresholds from trivial to large. National-class gymnasts' two-day performance variation was trivial for vault, small for floor and beam, and moderate for bars. When senior gymnasts competed for a third day the performance variation increased to moderate for vault. Across five days of Olympic competition there were trivial (e.g. CV%: vault = 0.8) to small (e.g. CV%: bars = 2.0) variations in performances between days on all apparatus. Olympians' performance score consistency is superior to senior, national-class competitors. The performance score consistency required for gymnasts who aspire to participate at the Olympics as a top-24 competitor is better than 3%.

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The present work was carried out to study the effects of mineral nutrition on peanut (Arachis hypogaea L) cv. IAC Runner-886 and hairy beggarticks (Bidens pilosa L) growth, when submitted to inter- and intraspecific competition. The treatments consisted of two peanut plants per pot, two hairy beggarticks per pot and one plant of each species per pot. The plants were nourished with Hoagland and Arnon (1950) complete solution, or without potassium, or without phosphorus or without nitrogen. Sixty days after planting, no inter- or intraspecific competition effect on growth characteristics of peanut was verified and nutrition was not a limiting factor to the culture. No interaction between competition and nutrition effects was observed for both species. The weed suffered more negative effects from intraspecific competition and nutrition. The absence of N had a pronounced effect compared to the other elements, resulting in a reduction in all the evaluated characteristics. The deficiency of nutrients and competition affected the weed more than the crop, showing that peanut was more competitive than hairy beggarticks.

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O presente experimento teve por objetivo estudar os efeitos da competição inter e intraespecífica envolvendo Glycine max (L.) Merril e Cyperus rotundus L. sobre as características das plantas e acúmulos de N, P, K, Ca e Mg pelas espécies envolvidas. Para tanto, estipulou-se um tratamento em que se desenvolveram três plantas de Glycine max e outro em que se desenvolveram 3 tubérculos de Cyperus rotundus por vaso. Para estudar os efeitos da competição intraespecífica, em dois outros tratamentos dobraram-se as populações por vaso. No estudo da competição interespecífica permitiu-se o desenvolvimento de três plantas de Glycine max e de três tubérculos de Cyperus rotundus num mesmo vaso. de uma maneira geral, pôde-se observar que principalmente devido às diferenças no hábito de crescimento das duas espécies, a expressão da competição inter e intraespecífica, em cada uma delas, assume aspectos distintos. No caso de Cyperus rotundus, o efeito do dobro da densidade pôde ser compensado, em parte, pela maior produção de manifestações epígeas e de tubérculos, aliados ao maior desenvolvimento dos tubérculos na menor densidade de plantio. No caso da competição interespecífica, os resultados sugerem um efeito decisivo do sombreamento de Leguminosae sobre o comportamento da Cyperaceae. Os padrões de efeitos da competição pelos nutrientes foi determinado também pelas diferenças no recrutamento dos elementos do solo pelas espécies envolvidas.

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Toxocariasis is caused by infection of man by Toxocara canis and Toxocara, cati larvae, the common roundworm of dogs and cats. Because larvae are difficult to detect in tissues, diagnosis is mostly based on serology. Non specific reactions are observed mainly due to cross-reactivity with Ascaris sp antigens. This investigation aimed at developing and evaluating an indirect antibody competition ELISA (IACE) employing a specific rabbit IgG anti-Toxocara canis excretory-secretory antigens as the competition antibody. in order to improve indirect ELISA specificity performed for toxocariasis diagnosis. For that, the rabbit IgG was previously absorbed by Ascaris suum adult antigens. Sensitivity and specificity of IACE were first evaluated in 28 serum samples of mice experimentally infected with T. canis embryonated eggs. Adopting cut-off value established in this population before infection, sensitivity and specificity were 100% after 20 days post-inoculation. For human population IACE was evaluated using sera from 440 patients with clinical signs of toxocariasis and the cut-off value was established with 60 serum samples from apparently healthy individuals. Using as reference test the indirect ELISA performed by Adolfo Lutz Institute, sensitivity was 60.2%, specificity was 98% and concordance was 77.3%. Repeatability of IACE was evaluated by the inter-reactions variation coefficient (2.4%).

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Ecological interactions between different species are not fixed, but they may depend, at least to some extent, on the particular genotypes involved as well as on the environmental conditions experienced by previous generations. We used a set of natural genotypes of Arabidopsis thaliana, that previously experienced contrasting nutrient and herbivory conditions, to test for the influences of genetic variation and maternal effects on competitive interactions between Arabidopsis and the weedy annuals Anagallis arvensis and Senecio vulgaris. We used activated carbon to discriminate between resource competition and allelopathy components of plant-plant interactions. There was a clear competitive hierarchy: Senecio > Arabidopsis > Anagallis. Although we found no evidence for allelopathic potential of Arabidopsis, our results indicate that both Anagallis and Senecio exerted negative (direct or indirect) allelopathic effects on Arabidopsis. There were significant differences among Arabidopsis genotypes in their competitive effects on both neighbor species, as well as in their response to competition. Maternal environments significantly influenced not only the growth and fitness of Arabidopsis itself, but also its competitive effect on Anagallis. We found, however, no evidence that maternal environments affected the competitive effect on Senecio or overall competitive response of Arabidopsis. Generally, resource competition played a greater role than allelopathy, and genotype effects were more important than maternal effects. Our study demonstrates that ecological interactions, such as plant competition, are complex and multi-layered, and that, in particular, the influence of genetic variation on interactions with other species should not be overlooked.

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Recent experimental evidence has shown that application of certain neurotrophic factors (NTs) to the developing primary visual cortex prevents the development of ocular dominance (OD) columns. One interpretation of this result is that afferents from the lateral geniculate nucleus compete for postsynaptic trophic factor in an activity-dependent manner. Application of excess trophic factor eliminates this competition, thereby preventing OD column formation. We present a model of OD column development, incorporating Hebbian synaptic modification and activity-driven competition for NT, which accounts for both normal OD column development as well as the prevention of that development when competition is removed. In the “control” situation, when available NT is below a critical amount, OD columns form normally. These columns form without weight normalization procedures and in the presence of positive inter-eye correlations. In the “experimental” case, OD column development is prevented in a local neighborhood in which excess NT has been added. Our model proposes a biologically plausible mechanism for competition between neural populations that is motivated by several pieces of experimental data, thereby accounting for both normal and experimentally perturbed conditions.

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The thrust of the argument presented in this chapter is that inter-municipal cooperation (IMC) in the United Kingdom reflects local government's constitutional position and its exposure to the exigencies of Westminster (elected central government) and Whitehall (centre of the professional civil service that services central government). For the most part councils are without general powers of competence and are restricted in what they can do by Parliament. This suggests that the capacity for locally driven IMC is restricted and operates principally within a framework constructed by central government's policy objectives and legislation and the political expediencies of the governing political party. In practice, however, recent examples of IMC demonstrate that the practices are more complex than this initial analysis suggests. Central government may exert top-down pressures and impose hierarchical directives, but there are important countervailing forces. Constitutional changes in Scotland and Wales have shifted the locus of central- local relations away from Westminster and Whitehall. In England, the seeding of English government regional offices in 1994 has evolved into an important structural arrangement that encourages councils to work together. Within the local government community there is now widespread acknowledgement that to achieve the ambitious targets set by central government, councils are, by necessity, bound to cooperate and work with other agencies. In recent years, the fragmentation of public service delivery has affected the scope of IMC. Elected local government in the UK is now only one piece of a complex jigsaw of agencies that provides services to the public; whether it is with non-elected bodies, such as health authorities, public protection authorities (police and fire), voluntary nonprofit organisations or for-profit bodies, councils are expected to cooperate widely with agencies in their localities. Indeed, for projects such as regeneration and community renewal, councils may act as the coordinating agency but the success of such projects is measured by collaboration and partnership working (Davies 2002). To place these developments in context, IMC is an example of how, in spite of the fragmentation of traditional forms of government, councils work with other public service agencies and other councils through the medium of interagency partnerships, collaboration between organisations and a mixed economy of service providers. Such an analysis suggests that, following changes to the system of local government, contemporary forms of IMC are less dependent on vertical arrangements (top-down direction from central government) as they are replaced by horizontal modes (expansion of networks and partnership arrangements). Evidence suggests, however that central government continues to steer local authorities through the agency of inspectorates and regulatory bodies, and through policy initiatives, such as local strategic partnerships and local area agreements (Kelly 2006), thus questioning whether, in the case of UK local government, the shift from hierarchy to network and market solutions is less differentiated and transformation less complete than some literature suggests. Vertical or horizontal pressures may promote IMC, yet similar drivers may deter collaboration between local authorities. An example of negative vertical pressure was central government's change of the systems of local taxation during the 1980s. The new taxation regime replaced a tax on property with a tax on individual residency. Although the community charge lasted only a few years, it was a highpoint of the then Conservative government policy that encouraged councils to compete with each other on the basis of the level of local taxation. In practice, however, the complexity of local government funding in the UK rendered worthless any meaningful ambition of councils competing with each other, especially as central government granting to local authorities is predicated (however imperfectly) on at least notional equalisation between those areas with lower tax yields and the more prosperous locations. Horizontal pressures comprise factors such as planning decisions. Over the last quarter century, councils have competed on the granting of permission to out-of-town retail and leisure complexes, now recognised as detrimental to neighbouring authorities because economic forces prevail and local, independent shops are unable to compete with multiple companies. These examples illustrate tensions at the core of the UK polity of whether IMC is feasible when competition between local authorities heightened by local differences reduces opportunities for collaboration. An alternative perspective on IMC is to explore whether specific purposes or functions promote or restrict it. Whether in the principle areas of local government responsibilities relating to social welfare, development and maintenance of the local infrastructure or environmental matters, there are examples of IMC. But opportunities have diminished considerably as councils lost responsibility for services provision as a result of privatisation and transfer of powers to new government agencies or to central government. Over the last twenty years councils have lost their role in the provision of further-or higher-education, public transport and water/sewage. Councils have commissioning power but only a limited presence in providing housing needs, social care and waste management. In other words, as a result of central government policy, there are, in practice, currently far fewer opportunities for councils to cooperate. Since 1997, the New Labour government has promoted IMC through vertical drivers and the development; the operation of these policy initiatives is discussed following the framework of the editors. Current examples of IMC are notable for being driven by higher tiers of government, working with subordinate authorities in principal-agent relations. Collaboration between local authorities and intra-interand cross-sectoral partnerships are initiated by central government. In other words, IMC is shaped by hierarchical drivers from higher levels of government but, in practice, is locally varied and determined less by formula than by necessity and function. © 2007 Springer.

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The title compound, C11H11NO3, has two mol-ecules in the asymmetric unit, which differ in the orientation of their side-chain OH groups, allowing them to form inter-molecular O - H⋯O hydrogen bonds to different acceptors. In one case, the acceptor is the OH group of the other mol-ecule, and in the other case it is an imide O=C group. This is the first example in the N-substituted phthalimide series in which independent mol-ecules have different types of acceptor. Mol-ecular-orbital calculations place the greatest negative charge on the OH group. © 2008 International Union of Crystallography.

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In this article we analyze asymmetric two-sided markets. Two types of agents are assumed to interact with each other and we assume that agents of one type derive utility from inter-group interactions, while the other type of agents benefit from intra-group rather than from inter-group interactions as it is assumed in the standard symmetric two-sided markets model. First, we consider a monopoly platform, then we analyze competing platforms, both with single-homing and multi-homing abilities.

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The purpose of my dissertation was to examine the competition between the U.S.-led Western bloc and the Soviet bloc in the less developed world during Détente. I assessed whether or not the Soviet bloc pushed for strategic gains in the less developed world in the middle-to-late 1970's and whether this contributed to the U.S. decision to abandon Détente in 1979. I made the attempt to test the international relations theory of balance of threat realism (Walt, 1992). I accomplished the test in two ways. First, I measured the foreign aid allocations (military and economic) made by each respective bloc towards the Third World by using a quantitative approach. Second, I examined U.S. archives using the process-tracing/historical method. The U.S. archives gave me the ability to evaluate how U.S. decision-makers and U.S. intelligence agencies interpreted the actions of the Soviet bloc. They also gave me the chance to examine the U.S. response as we evaluated the policies that were pushed by key U.S. decision-makers and intelligence agencies. On the question of whether or not the Soviet bloc was aggressive, the quantitative evidence suggested that it was not. Instead, the evidence found the Western-bloc to have been more aggressive in the less developed world. The U.S. archives also showed Soviet actions to have been defensive. Key U.S. decision-makers and intelligence agencies attested to this. Finally, the archives show that U.S. officials pushed for aggressive actions against the Third World during the final years of Détente. Thus, balance of threat realism produced an incorrect assessment that U.S. aggression in the late 1970's was a response to Soviet aggression during Détente. The evidence suggests structural Marxism and domestic politics can better explain U.S./Western actions. The aggressive foreign aid allocations of the West, coupled with evidence of U.S. decision-makers/agencies vehemently concerned about the long-term prospects of the West, strengthened structural Marxism. Domestic politics can also claim to explain the actions of U.S. decision-makers. I found extensive archival evidence of bureaucratic inter-agency conflict between the State Department and other intelligence agencies in areas of strategic concern to the U.S.