118 research outputs found

    Banking Geography and Cross-Fertilization in the Productivity Growth of US Commercial Banks

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    The US banking industry offers a unique, natural and fertile environment to study geography's effects on banks' behavior and performance. The literature on banks' operating performance, while extensive, says little about the influence of spatial interactions on banks' performance. We compute and examine, using a physical distance-based spatio-temporal empirical model, the state-wide total factor productivity growth (TFPG) indices of US commercial banks for each state for the 1971-1995 period. We observe that the productivity growth of commercial banks in state i depends strongly, positively, and contemporaneously on the productivity growth of commercial banks located in state i's contiguous states. Further, “regulatory space” appears to induce frictions and lessen the documented spatial interactions. These findings support our plea that research on commercial banking sector's behavior need to pay a particular attention to the effects of banking geography.Spatial, Commercial Banks, Total Factor Productivity Growth, Kalman Filter

    Non-conventional viticulture as a viable system: a case study in Italy

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    The food crisis of 2008 and the current financial crisis, coupled with concerns of climate change, have fueled a renewed interest in alternative food production systems, namely, local, organic and sustainable food systems. In many countries, research shows that in the medium to long run, organic and local food systems will be the most resistant and will provide an effective means to attain food security. Moreover, such systems also support social and cultural variables and can therefore be important in coping strategies in times of crisis. Reliable, and sustainable systems will help bear the burden of crises as well as be economically profitable as more people prefer to eat local due to environmental or economic concerns. Organic or biodynamic production systems in a local setting offer both economic and ecological advantages, from the producer and consumer perspectives. While wine is not food, it supports a wide range of people, industries, and activities, and therefore plays an important role in local economies, especially in countries like Italy. It is also deeply rooted in tradition, and is rich in local knowledge and techniques. Wine is also different in that its quality aspect is an important factor especially in terms of customer acceptance. Wine is often highly differentiated, even within the same region. The paper aims to provide a deeper understanding of the viability of the non-conventional (organic/biodynamic) viticulture and proposes a model for analysis of its economic, social and cultural context to measure impacts in an effort to evaluate the validity of the argument that these types of systems are viable and even superior options. Interviews with producers and local experts, and actual sales data will be used to identify the social, environmental and economic advantages of such systems, as well as problems, such as diseconomies of scale. Using selected indicators, the paper will also suggest policies to overcome these problems and propose some marketing strategies to render such systems more viable. In particular, the paper will evaluate for a given locality in Italy: (i) The profitability for the producer in the actual global and regional context, with competition from larger and conventional producers (ii) The probability of such methods to generate positive externalities from field to glass (iii) The feasibility of providing a higher quality product at a reasonable price for the consumer (iv) The direct and indirect impacts of this type of system for the local economy. (v) Social aspects in terms of trust and a closer connection between consumers and producers (vi) Environmental/ecological implications The above analysis will then be used to describe the particular viticulture system and select indicators for social, economic and environmental viability. These will be used in defining selected policy measures to minimize the costs and negative impacts and help define targeted marketing strategies

    Vortex Lattices in Strongly Confined Quantum Droplets

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    Bose mixture quantum droplets display a fascinating stability that relies on quantum fluctuations to prevent collapse driven by mean-field effects. Most droplet research focuses on untrapped or weakly trapped scenarios, where the droplets exhibit a liquid-like flat density profile. When weakly trapped droplets rotate, they usually respond through center-of-mass motion or splitting instability. Here, we study rapidly rotating droplets in the strong external confinement limit where the external potential prevents splitting and the center-of-mass excitation. We find that quantum droplets form a triangular vortex lattice as in single-component repulsive Bose-Einstein condensates (BEC), but the overall density follows the analytical Thomas-Fermi profile obtained from a cubic equation. We observe three significant differences between rapidly rotating droplets and repulsive BECs. First, the vortex core size changes markedly at finite density, visible in numerically obtained density profiles. We analytically estimate the vortex core sizes from the droplets' coherence length and find good agreement with the numerical results. Second, the change in the density profile gives a slight but observable distortion to the lattice, which agrees with the distortion expected due to nonuniform superfluid density. Lastly, unlike a repulsive BEC, which expands substantially as the rotation frequency approaches the trapping frequency, rapidly rotating droplets show only a fractional change in their size. We argue that this last point can be used to create clouds with lower filling factors, which may facilitate reaching the elusive strongly correlated regime

    Dye lasing in optically manipulated liquid aerosols

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    We report lasing in airborne, rhodamine B-doped glycerol-water droplets with diameters ranging between 7.7 and 11.0 mu m, which were localized using optical tweezers. While being trapped near the focal point of an infrared laser, the droplets were pumped with a Q-switched green laser. Our experiments revealed nonlinear dependence of the intensity of the droplet whispering gallery modes (WGMs) on the pump laser fluence, indicating dye lasing. The average wavelength of the lasing WGMs could be tuned between 600 and 630 nm by changing the droplet size. These results may lead to new ways of probing airborne particles, exploiting the high sensitivity of stimulated emission to small perturbations in the droplet laser cavity and the gain medium

    Cleaning up our acts: Psychological interventions to reduce engine idling and improve air quality

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    A large-scale field experiment tested psychological interventions to reduce engine idling at long-wait stops. Messages based on theories of normative influence, outcome efficacy, and self-regulation were displayed approaching railway crossing on street poles. Observers coded whether drivers (N = 6049) turned off their engine while waiting at the railway crossings (only 27.2% did so at baseline). Automatic air quality monitors recorded levels of pollutants during barrier down times. To different degrees, the social norm and outcome efficacy messages successfully increased the proportion of drivers who turned off their engines (by 42% and 25%, respectively) and significantly reduced concentrations of atmospheric particulate matter (PM2.5) 2 m above ground level. Thus, the environment was improved through behavior change. Moreover, of both practical and theoretical significance, there was an ‘accelerator effect’, in line with theories of normative influence whereby the social norm message was increasingly effective as the volume of traffic increased

    Microdevices for extensional rheometry of low viscosity elastic liquids : a review

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    Extensional flows and the underlying stability/instability mechanisms are of extreme relevance to the efficient operation of inkjet printing, coating processes and drug delivery systems, as well as for the generation of micro droplets. The development of an extensional rheometer to characterize the extensional properties of low viscosity fluids has therefore stimulated great interest of researchers, particularly in the last decade. Microfluidics has proven to be an extraordinary working platform and different configurations of potential extensional microrheometers have been proposed. In this review, we present an overview of several successful designs, together with a critical assessment of their capabilities and limitations

    Miniaturized Embryo Array for Automated Trapping, Immobilization and Microperfusion of Zebrafish Embryos

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    Zebrafish (Danio rerio) has recently emerged as a powerful experimental model in drug discovery and environmental toxicology. Drug discovery screens performed on zebrafish embryos mirror with a high level of accuracy the tests usually performed on mammalian animal models, and fish embryo toxicity assay (FET) is one of the most promising alternative approaches to acute ecotoxicity testing with adult fish. Notwithstanding this, automated in-situ analysis of zebrafish embryos is still deeply in its infancy. This is mostly due to the inherent limitations of conventional techniques and the fact that metazoan organisms are not easily susceptible to laboratory automation. In this work, we describe the development of an innovative miniaturized chip-based device for the in-situ analysis of zebrafish embryos. We present evidence that automatic, hydrodynamic positioning, trapping and long-term immobilization of single embryos inside the microfluidic chips can be combined with time-lapse imaging to provide real-time developmental analysis. Our platform, fabricated using biocompatible polymer molding technology, enables rapid trapping of embryos in low shear stress zones, uniform drug microperfusion and high-resolution imaging without the need of manual embryo handling at various developmental stages. The device provides a highly controllable fluidic microenvironment and post-analysis eleuthero-embryo stage recovery. Throughout the incubation, the position of individual embryos is registered. Importantly, we also for first time show that microfluidic embryo array technology can be effectively used for the analysis of anti-angiogenic compounds using transgenic zebrafish line (fli1a:EGFP). The work provides a new rationale for rapid and automated manipulation and analysis of developing zebrafish embryos at a large scale

    Hes5 Expression in the Postnatal and Adult Mouse Inner Ear and the Drug-Damaged Cochlea

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    The Notch signaling pathway is known to have multiple roles during development of the inner ear. Notch signaling activates transcription of Hes5, a homologue of Drosophila hairy and enhancer of split, which encodes a basic helix-loop-helix transcriptional repressor. Previous studies have shown that Hes5 is expressed in the cochlea during embryonic development, and loss of Hes5 leads to overproduction of auditory and vestibular hair cells. However, due to technical limitations and inconsistency between previous reports, the precise spatial and temporal pattern of Hes5 expression in the postnatal and adult inner ear has remained unclear. In this study, we use Hes5-GFP transgenic mice and in situ hybridization to report the expression pattern of Hes5 in the inner ear. We find that Hes5 is expressed in the developing auditory epithelium of the cochlea beginning at embryonic day 14.5 (E14.5), becomes restricted to a particular subset of cochlear supporting cells, is downregulated in the postnatal cochlea, and is not present in adults. In the vestibular system, we detect Hes5 in developing supporting cells as early as E12.5 and find that Hes5 expression is maintained in some adult vestibular supporting cells. In order to determine the effect of hair cell damage on Notch signaling in the cochlea, we damaged cochlear hair cells of adult Hes5-GFP mice in vivo using injection of kanamycin and furosemide. Although outer hair cells were killed in treated animals and supporting cells were still present after damage, supporting cells did not upregulate Hes5-GFP in the damaged cochlea. Therefore, absence of Notch-Hes5 signaling in the normal and damaged adult cochlea is correlated with lack of regeneration potential, while its presence in the neonatal cochlea and adult vestibular epithelia is associated with greater capacity for plasticity or regeneration in these tissues; which suggests that this pathway may be involved in regulating regenerative potential
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