564 research outputs found

    Culture and Innovation in Peru from a Management Perspective

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    Political stability, macro-economic caution, and the aggressive pursuit of free trade have enabled Peru to emerge as one of the fastest growing economies in Latin America. This economic expansion has created heightened interest in the evolution of corporate culture and its influence on firm performance. This paper examines organizational performance in relation to the influence of cultural values on innovation by means of a survey of upper level managers. Analysis of the survey results indicates that there was a positive relation between innovation and power distance and uncertainty. Survey findings show no relationship between innovation and individualism nor innovation and masculinity. Practical implications indicate that the cultural values of declining power distance and lower aversion to uncertainty may influence the effective implementation of an innovation strategy in firms operating in Peru

    Erratum to: The Drosophila transcriptional network is structured by microbiota

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    An Entomopathogenic Nematode by Any Other Name

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    Among the diversity of insect-parasitic nematodes, entomopathogenic nematodes (EPNs) are distinct, cooperating with insect-pathogenic bacteria to kill insect hosts. EPNs have adapted specific mechanisms to associate with and transmit bacteria to insect hosts. New discoveries have expanded this guild of nematodes and refine our understanding of the nature and evolution of insect–nematode associations. Here, we clarify the meaning of “entomopathogenic” in nematology and argue that EPNs must rapidly kill their hosts with the aid of bacterial partners and must pass on the associated bacteria to future generations

    Innovation, learning and performance in a resource-rich emerging economy

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    Background: This article compares the performance of firms in resource-rich sectors of the Peruvian economy with that of businesses operating in service sectors.   Objectives: In so doing, the research seeks to examine whether innovation is managed differently by firms operating in different sectors of a developing-country economy and whether the performance of firms in an emerging economy may be influenced by innovation and learning practices at the sectoral level.   Method: Data were acquired through a survey of overwhelmingly middle managers working in Peru.   Results: According to the survey findings, the performance of firms in the resource-rich sectors appeared to be uninfluenced by innovation or involvement in organisational learning. In contrast, firms in the service sectors not only exhibited an innovation orientation and involvement in learning but also reported higher sales growth.   Conclusion: The study concludes that firms operating in the resource-rich sectors of Peru’s economy do not appear to benefit from engaging in innovation or learning at this point in time, whereas such activities are advantageous for service sector businesses. Therefore, the relationship between innovation, learning and performance may be influenced not just by the type of economy but also by the sector in which the firms are operating

    Regulation of endothelial-specific transgene expression by the LacI repressor protein in vivo

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    Genetically modified mice have played an important part in elucidating gene function in vivo. However, conclusions from transgenic studies may be compromised by complications arising from the site of transgene integration into the genome and, in inducible systems, the non-innocuous nature of inducer molecules. The aim of the present study was to use the vascular system to validate a technique based on the bacterial lac operon system, in which transgene expression can be repressed and de-repressed by an innocuous lactose analogue, IPTG. We have modified an endothelium specific promoter (TIE2) with synthetic LacO sequences and made transgenic mouse lines with this modified promoter driving expression of mutant forms of connexin40 and an independently translated reporter, EGFP. We show that tissue specificity of this modified promoter is retained in the vasculature of transgenic mice in spite of the presence of LacO sequences, and that transgene expression is uniform throughout the endothelium of a range of adult systemic and cerebral arteries and arterioles. Moreover, transgene expression can be consistently down-regulated by crossing the transgenic mice with mice expressing an inhibitor protein LacI(R), and in one transgenic line, transgene expression could be de-repressed rapidly by the innocuous inducer, IPTG. We conclude that the modified bacterial lac operon system can be used successfully to validate transgenic phenotypes through a simple breeding schedule with mice homozygous for the LacI(R) protein.CEH and KIM acknowledge funding support from NH&MRC Project Grant #471421

    Electron Power-Law Spectra in Solar and Space Plasmas

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    Particles are accelerated to very high, non-thermal energies in solar and space plasma environments. While energy spectra of accelerated electrons often exhibit a power law, it remains unclear how electrons are accelerated to high energies and what processes determine the power-law index ÎŽ\delta. Here, we review previous observations of the power-law index ÎŽ\delta in a variety of different plasma environments with a particular focus on sub-relativistic electrons. It appears that in regions more closely related to magnetic reconnection (such as the `above-the-looptop' solar hard X-ray source and the plasma sheet in Earth's magnetotail), the spectra are typically soft (ή≳\delta \gtrsim 4). This is in contrast to the typically hard spectra (ÎŽâ‰Č\delta \lesssim 4) that are observed in coincidence with shocks. The difference implies that shocks are more efficient in producing a larger non-thermal fraction of electron energies when compared to magnetic reconnection. A caveat is that during active times in Earth's magnetotail, ÎŽ\delta values seem spatially uniform in the plasma sheet, while power-law distributions still exist even in quiet times. The role of magnetotail reconnection in the electron power-law formation could therefore be confounded with these background conditions. Because different regions have been studied with different instrumentations and methodologies, we point out a need for more systematic and coordinated studies of power-law distributions for a better understanding of possible scaling laws in particle acceleration as well as their universality.Comment: 67 pages, 15 figures; submitted to Space Science Reviews; comments welcom

    Clouds, shadows, or twilight? Mayfly nymphs recognise the difference

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    1. We examined the relative changes in light intensity that initiate night-time locomotor activity changes in nymphs of the mayfly, Stenonema modestum (Heptageniidae). Tests were carried out in a laboratory stream to examine the hypothesis that nymphs increase their locomotion in response to the large and sustained reductions in relative light intensity that take place during twilight but not to short-term daytime light fluctuations or a minimum light intensity threshold. Ambient light intensity was reduced over a range of values representative of evening twilight. Light was reduced over the same range of intensities either continuously or in discrete intervals while at the same time nymph activity on unglazed tile substrata was video recorded. 2. Nymphs increased their locomotor activity during darkness in response to large, sustained relative light decreases, but not in response to short-term, interrupted periods of light decrease. Nymphs did not recognise darkness unless an adequate light stimulus, such as large and sustained relative decrease in light intensity, had taken place. 3. We show that nymphs perceive light change over time and respond only after a lengthy period of accumulation of light stimulus. The response is much lengthier than reported for other aquatic organisms and is highly adaptive to heterogeneous stream environments

    Impulsive phase flare energy transport by large-scale Alfven waves and the electron acceleration problem

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    The impulsive phase of a solar flare marks the epoch of rapid conversion of energy stored in the pre-flare coronal magnetic field. Hard X-ray observations imply that a substantial fraction of flare energy released during the impulsive phase is converted to the kinetic energy of mildly relativistic electrons (10-100 keV). The liberation of the magnetic free energy can occur as the coronal magnetic field reconfigures and relaxes following reconnection. We investigate a scenario in which products of the reconfiguration - large-scale Alfven wave pulses - transport the energy and magnetic-field changes rapidly through the corona to the lower atmosphere. This offers two possibilities for electron acceleration. Firstly, in a coronal plasma with beta < m_e/m_p, the waves propagate as inertial Alfven waves. In the presence of strong spatial gradients, these generate field-aligned electric fields that can accelerate electrons to energies on the order of 10 keV and above, including by repeated interactions between electrons and wavefronts. Secondly, when they reflect and mode-convert in the chromosphere, a cascade to high wavenumbers may develop. This will also accelerate electrons by turbulence, in a medium with a locally high electron number density. This concept, which bridges MHD-based and particle-based views of a flare, provides an interpretation of the recently-observed rapid variations of the line-of-sight component of the photospheric magnetic field across the flare impulsive phase, and offers solutions to some perplexing flare problems, such as the flare "number problem" of finding and resupplying sufficient electrons to explain the impulsive-phase hard X-ray emission.Comment: 31 pages, 6 figure
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