669 research outputs found

    ESTIMATION OF FIRM-VARYING, INPUT-SPECIFIC EFFICIENCIES IN DAIRY PRODUCTION

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    Firm-varying production technologies were estimated using random coefficients regression methods for a sample of Massachusetts dairy farms. Results were compared to OLS Cobb-Douglas production function estimates. The random coefficients regression model was found to virtually eliminate conventionally measured firm technical inefficiencies by estimating individual firm technologies and ascribing remaining inefficiencies to specific inputs. Input-specific measures of firm inefficiencies showed hired labor, land, and machinery inputs to be used in excess of efficient levels. Livestock supplies were underutilized by all farms. Efficiencies of feed, crop materials, fuels, and utilities varied, although estimated means were closer to optimal levels.Production Economics,

    Functional constraints in the evolution of brain circuits

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    Regardless of major anatomical and neurodevelopmental differences, the vertebrate isocortex shows a remarkably well-conserved organization. In the isocortex, reciprocal connections between excitatory and inhibitory neurons are distributed across multiple layers, encompassing modular, dynamical and recurrent functional networks during information processing. These dynamical brain networks are often organized in neuronal assemblies interacting through rhythmic phase relationships. Accordingly, these oscillatory interactions are observed across multiple brain scale levels, and they are associated with several sensory, motor, and cognitive processes. Most notably, oscillatory interactions are also found in the complete spectrum of vertebrates. Yet, it is unknown why this functional organization is so well conserved in evolution. In this perspective, we propose some ideas about how functional requirements of the isocortex can account for the evolutionary stability observed in microcircuits across vertebrates. We argue that isocortex architectures represent canonical microcircuits resulting from: (i) the early selection of neuronal architectures based on the oscillatory excitatory-inhibitory balance, which lead to the implementation of compartmentalized oscillations and (ii) the subsequent emergence of inferential coding strategies (predictive coding), which are able to expand computational capacities. We also argue that these functional constraints may be the result of several advantages that oscillatory activity contributes to brain network processes, such as information transmission and code reliability. In this manner, similarities in mesoscale brain circuitry and input-output organization between different vertebrate groups may reflect evolutionary constraints imposed by these functional requirements, which may or may not be traceable to a common ancestor

    Global patterns in anaphylaxis due to specific foods: a systematic review

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    Background There are increasing global data relating to prevalence of food allergy and food-induced anaphylaxis, however this is often based on surrogate measures of sensitization rather than objective symptoms at food challenge. In terms of protecting food-allergic consumers from reactions, there has been no global survey assessing geographical differences in the proportion of anaphylaxis triggered by specific foods. Objective To identify common triggers for food-induced anaphylaxis, and how these vary from country to country. Methods Systematic review of relevant reports published between January 2010 and November 2020. Results were reported following PRISMA guidelines. Publications were screened and data extracted by two independent reviewers, and risk of bias assessed. Results Sixty-five studies (encompassing 41 countries and all 6 regions as defined by the Food & Agriculture Organization of the United Nations) were included. Significant regional variations in the most common triggers of food-anaphylaxis were seen, however, in general there was good agreement between local legislative requirements for allergen disclosure and the commonest allergens for each region/nation. Conclusions Local legislation for allergen disclosure generally reflect those allergens commonly responsible for food-anaphylaxis. Cow’s milk and crustacea appear to be cause a higher proportion of anaphylaxis compared to peanut in some regions

    MODELLING ELASTICITY OF INJECTION MOULDED SHORT FIBRE REINFORCED POLYMERS: COMPARISON BETWEEN EXPERIMENTAL AND ANALYTICAL APPROACHES

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    In this work we analysed a sample of short fibre reinforced polyamide extracted from an injection moulded plate. We derived local values of the elastic constants by two different numerical methods, one based on simulation and one based on the reconstruction of the sample's microstructure by micro - CT. Results were compared in terms of moduli of elasticity, assuming an orthotropic material model. Fibre orientation was first simulated by process simulation and results were checked against experimental data obtained by the optical section method. Then, fibre orientation data were used for micro-mechanical modelling of the elastic behaviour by means of mean field homogenisation tools. The experimentally based approach was based on micro computed tomography reconstructions of the inner structure of samples extracted from the injection moulded plate. Using numerical models based on the Cell Method, the elastic behaviour of the reconstructed volume was simulated and results were compared with analytical models based on process simulations and homogenization

    The Kuramoto model: A simple paradigm for synchronization phenomena

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    Synchronization phenomena in large populations of interacting elements are the subject of intense research efforts in physical, biological, chemical, and social systems. A successful approach to the problem of synchronization consists of modeling each member of the population as a phase oscillator. In this review, synchronization is analyzed in one of the most representative models of coupled phase oscillators, the Kuramoto model. A rigorous mathematical treatment, specific numerical methods, and many variations and extensions of the original model that have appeared in the last few years are presented. Relevant applications of the model in different contexts are also included

    Immunomodulatory IL-23 receptor antagonist peptide nanocoatings for implant soft tissue healing

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    Peri-implantitis, caused by an inflammatory response to pathogens, is the leading cause of dental implant failure. Poor soft tissue healing surrounding implants - caused by inadequate surface properties - leads to infection, inflammation, and dysregulated keratinocyte and macrophage function. One activated inflammatory response, active around peri-implantitis compared to healthy sites, is the IL-23/IL-17A cytokine axis. Implant surfaces can be synthesized with peptide nanocoatings to present immunomodulatory motifs to target peri-implant keratinocytes to control macrophage polarization and regulate inflammatory axises toward enhancing soft tissue healing.We synthesized an IL-23 receptor (IL-23R) noncompetitive antagonist peptide nanocoating using silanization and evaluated keratinocyte secretome changes and macrophage polarization (M1-like "pro-inflammatory" vs. M2-like "pro-regenerative").IL-23R antagonist peptide nanocoatings were successfully synthesized on titanium, to model dental implant surfaces, and compared to nonfunctional nanocoatings and non-coated titanium. IL-23R antagonist nanocoatings significantly decreased keratinocyte IL-23, and downstream IL-17A, expression compared to controls. This peptide noncompetitive antagonistic function was demonstrated under lipopolysaccharide stimulation. Large scale changes in keratinocyte secretome content, toward a pro-regenerative milieu, were observed from keratinocytes cultured on the IL-23R antagonist nanocoatings compared to controls. Conditioned medium collected from keratinocytes cultured on the IL-23R antagonist nanocoatings polarized macrophages toward a M2-like phenotype, based on increased CD163 and CD206 expression and reduced iNOS expression, compared to controls.Our results support development of IL-23R noncompetitive antagonist nanocoatings to reduce the pro-inflammatory IL-23/17A pathway and augment macrophage polarization toward a pro-regenerative phenotype. Immunomodulatory implant surface engineering may promote soft tissue healing and thereby reduce rates of peri-implantitis.Copyright © 2023 Elsevier Inc. All rights reserved

    Fuzzy systems and neural networks XML schemas for soft computing

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    This article presents an XML[2] based language for the specification of objects in the Soft Computing area. The design promotes reuse and takes a compositional approach in which more complex constructs are built from simpler ones; it is also independent of implementation details as the definition of the language only states the expected behaviour of every possible implementation. Here the basic structures for the specification of concepts in the Fuzzy Logic area are described and a simple construct for a generic neural network model is introduced
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