915 research outputs found

    Dealing with the tensions between innovation and internationalization in SMEs: A dynamic capability view

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    Previous literature disagrees on the fact that innovation and internationalization are decisions with a complementary effect on the performance of small and medium enterprises (SMEs) performance. We reconcile the contrasting views on this topic by using a dynamic capability perspective. We show that the simultaneous involvement in research and development (R&D) and export activities positively impacts SMEs’ profitability when such firms collaborate with universities and research centers, or when their international experience involves a diverse set of geographical markets. The magnitude of these moderations is different for low and high performers, thereby showing the lack of a “one best way” to successfully achieve complementarity between R&D and internationalization decisions

    Electron acceleration in solar flares: observations versus numerical simulations

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    We use RHESSI hard X-ray observations to constrain acceleration of solar flare electrons, generally considered to be a primary recipient of the released energ

    Entrepreneurship Education: the impact of different teaching models on the development of new ventures

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    The creation of innovative businesses (startups and spinoffs) is a phenomenon capable of stimulating the economy. The literature finds that entrepreneurship education (EE) impacts entrepreneurial intention. The aim of this research is to enter the black box of entrepreneurship teaching models in order to uncover their different impact on the creation of university entrepreneurial outcome. University entrepreneurial outcome is measured by the number of spinoffs created by 80 US universities in the Association of University Technology (AUTM) database from 2011 to 2014. This research, through analyses of 1,262 entrepreneurship courses in US universities along a time span of 4 years, shows that demand models and the competence models have a positive impact on the creation of academic spinoffs. Implications for professors teaching entrepreneurship, universities, policy makers and students are discussed

    Role of Confocal Laser Endomicroscopy in Detection of Residual Barrett's Esophagus after Radiofrequency Ablation

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    Endoscopic endoluminal radiofrequency ablation (RFA) is a novel and promising modality for Barrett's esophagus (BE) treatment. Actually the only surveillance method after the ablation treatment is random biopsies throughout the whole treated area. Confocal laser endomicroscopy (CLE) is a new endoscopic imaging tool that permits high-resolution microscopic examination of the gastrointestinal tract. The technology has garnered increasing attention because of its ability to provide real-time “optical” biopsy specimens, with a very high sensitivity and specificity. This paper summarize the potential application of CLE in the surveillance of the reepithelialization of BE, after endoscopic RFA

    Hadronic mass and q^2 moments of charmless semileptonic B decay distributions

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    We report OPE predictions for hadronic mass and q^2 moments in inclusive semileptonic B decays without charm, taking into account experimental cuts on the charged lepton energy and on the hadronic invariant mass, and address the related theoretical uncertainty.Comment: 16 pages, 1 figure; v3: we have corrected a mistake in the code that produced the numerical results; tables replaced, small changes in the tex

    Plastic responses of some life history traits and cellular components of body size in Aphidius ervi as related to the age of its host Acyrthosiphon pisum

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    Phenotypic plasticity of wing size and shape has been evaluated in Aphidius ervi developing in its host, Acyrthosiphon pisum, parasitized at seven different ages. The parasitoid wing size was used as an estimator of both whole body size and its cellular composition. No size difference was observed in A. ervi adults emerged from aphids 1, 2 or 3 days old at parasitization. Body size then increased in A. ervi emerged from hosts older at parasitization. Body size values as related to host age at parasitization were achieved by adjusting developmental time, developmental rate or both. Parasitoids of similar size, but developed in hosts parasitized at different ages, had different wing cellular composition, while the increase of parasitoid body size was related to a general increase in both cell area and cell number. These results seem to suggest a trade-off between adult size and developmental time, at least for parasitoids developed at the two extremes of host ages at parasitization, and that A. ervi can reach the same adult size via different trajectories, adapting its ontogenetic processes. Wing shape was typical for all the different parasitoid classes considered and differed strongly between males and females, independent of their size. Parasitoid males (haploids) and females (diploids) did not differ in either cell area or cell number, suggesting a possible sex-determined dosage compensation in somatic tissue endoreplication

    Prey abundance and intraguild predation between Adalia bipunctata (Coleoptera: Coccinellidae) and Macrolophus pygmaeus (Hemiptera: Miridae)

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    Macrolophus pygmaeus Rambur (Hemiptera: Miridae) and Adalia bipunctata (L.) (Coleoptera: Coccinellidae) are two predatory insects commonly used as biological control agents. In order to determine the incidence with which both species attack and eat each other [Intraguild predation (IGP)], the direction and symmetry of the interaction between A. bipunctata and M. pygmaeus were characterized. In addition, whether the intensity of IGP between these two predators increased when the number of extraguild prey Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae) decreased, was also determined. Unidirectional sensu stricto IGP between A. bipunctata and M. pygmaeus was recorded: when IGP occurred, A. bipunctata was always the IG predator that killed and ate M. pygmaeus, the IG prey. However, the intensity of IGP was a function of the abundance of the extraguild prey, A. pisum, since IGP increased when the number of extraguild prey decreased. These results are discussed in terms of theoretical models that predict stability and the outcome of using natural enemies to control pests

    Plastic responses of some life history traits and cellular components of body size in Aphidius ervi as related to the age of its host Acyrthosiphon pisum

    Get PDF
    Phenotypic plasticity of wing size and shape has been evaluated in Aphidius ervi developing in its host, Acyrthosiphon pisum, parasitized at seven different ages. The parasitoid wing size was used as an estimator of both whole body size and its cellular composition. No size difference was observed in A. ervi adults emerged from aphids 1, 2 or 3 days old at parasitization. Body size then increased in A. ervi emerged from hosts older at parasitization. Body size values as related to host age at parasitization were achieved by adjusting developmental time, developmental rate or both. Parasitoids of similar size, but developed in hosts parasitized at different ages, had different wing cellular composition, while the increase of parasitoid body size was related to a general increase in both cell area and cell number. These results seem to suggest a trade-off between adult size and developmental time, at least for parasitoids developed at the two extremes of host ages at parasitization, and that A. ervi can reach the same adult size via different trajectories, adapting its ontogenetic processes. Wing shape was typical for all the different parasitoid classes considered and differed strongly between males and females, independent of their size. Parasitoid males (haploids) and females (diploids) did not differ in either cell area or cell number, suggesting a possible sex-determined dosage compensation in somatic tissue endoreplication

    Transgenerational plasticity in aphids reared in a poor-resource environment

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    : The changing environmental conditions can affect insect biology over multiple generations and phenotypic plasticity is important for coping with these changes. Transgenerational plasticity occurs when the environment in which the parents developed influences the plastic response of the offspring phenotype. In the present study, the plastic effects of resource limitation on important life history traits such as body size, fecundity, survival, and resistance to starvation of the pea aphid Acyrthosiphon pisum were investigated over two generations. This study focused on understanding how resource limitation can determine an adaptive expression of maternal effects and transgenerational plasticity in fitness-related traits. Aphids showed phenotypic plasticity for the life history traits investigated, as they performed better when grown in an optimal environment than in a resource-poor one. Also, aphids had a poorer performance if their mothers were raised in a resource-poor environment. The effects of transgenerational plasticity were observed only in response to resistance to starvation, through increased survival in the offspring of the mother reared in a resource-poor environment, suggesting an evolutionary bet-hedging strategy. The results of this study showed that the effects of adaptive transgenerational plasticity may be partially masked in stressful environments, where developmental problems instead predominate. More information on the transgenerational response to resource limitation across generations can contribute to a better understanding of aphid biology
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