258 research outputs found
Pre-Analytical and Analytical Critical Factors Influencing the High Variability of the Concentrations Levels of Alzheimer Disease Biomarkers in Cerebral Spinal Fluid
Potential of multi-species livestock farming to improve the sustainability of livestock farms: A review.
Diversified farming systems are proposed as a major mechanism to address the many sustainability issues of today's agriculture. Multi-species livestock farming, i.e. keeping two or more animal species simultaneously on the same farm, is an option that has received little attention to date. Moreover, most studies of multi-species livestock farming are limited, usually focusing on selected dimensions of farm sustainability and addressing lower organizational levels (i.e. within the farm) and rather limited time horizons (e.g. a few weeks in a grazing season). Thus, a comprehensive assessment of multi-species livestock farming in terms of farm sustainability is lacking. In this context, we outline and discuss potential benefits and limitations of multi-species livestock farming for livestock farm sustainability from existing literature and list issues on multi-species livestock farming requiring further research. We show that multi-species livestock farming has the potential to improve the three dimensions of sustainability reviewed - economic viability for farmers, environmental soundness and social acceptability by being respectful of animals and humans - as long as locally relevant farming practices are implemented, especially an appropriate stocking rate during grazing. If relevant practices are not observed, multi-species livestock farming may produce undesirable effects, such as competition for resource acquisition during grazing, parasitic cross-infection and more intense work peaks. Therefore, we identify four focal research areas for multi-species livestock farming. First, characterizing the management of multi-species livestock farms. To do this, we suggest considering the integration of production enterprises (e.g. cattle and sheep enterprises)
within the farm from three perspectives: farming practices (e.g. grazing management), work organization and sales. Second, exploring the complementarity of livestock species on multi-species livestock farms. This is especially true for species combinations that have been largely ignored (e.g. ruminants and monogastrics), even though they may have potential due to complementary diet compositions and resource-acquisition strategies. Third, assessing the sustainability of multi-species livestock farm scenarios (current or alternative) according to the management practices and production conditions, which requires adapting existing methods/models or developing new ones. Fourth, characterizing conditions for success and obstacles for multi-species livestock farming along the value chain from production to consumption, considering stakeholders' objectives, work habits and constraints. Increasing understanding should help prioritize actions and organize them to scale up multi-species livestock farming
A machine learning approach for characterizing soil contamination in the presence of physical site discontinuities and aggregated samples
Rehabilitation of contaminated soils in urban areas is in high demand because of the appreciation of land value associated with the increased urbanization. Moreover, there are financial incentives to minimize soil characterization uncertainties. Minimizing uncertainty is achieved by providing models that are better representation of the true site characteristics. In this paper, we propose two new probabilistic formulations compatible with Gaussian Process Regression (GPR) and enabling (1) to model the experimental conditions where contaminant concentration is quantified from aggregated soil samples and (2) to model the effect of physical site discontinuities. The performance of approaches proposed in this paper are compared using a Leave One Out Cross-Validation procedure (LOO-CV). Results indicate that the two new probabilistic formulations proposed outperform the standard Gaussian Process Regression
Rubber Impact on 3D Textile Composites
A low velocity impact study of aircraft tire rubber on 3D textile-reinforced composite plates was performed experimentally and numerically. In contrast to regular unidirectional composite laminates, no delaminations occur in such a 3D textile composite. Yarn decohesions, matrix cracks and yarn ruptures have been identified as the major damage mechanisms under impact load. An increase in the number of 3D warp yarns is proposed to improve the impact damage resistance. The characteristic of a rubber impact is the high amount of elastic energy stored in the impactor during impact, which was more than 90% of the initial kinetic energy. This large geometrical deformation of the rubber during impact leads to a less localised loading of the target structure and poses great challenges for the numerical modelling. A hyperelastic Mooney-Rivlin constitutive law was used in Abaqus/Explicit based on a step-by-step validation with static rubber compression tests and low velocity impact tests on aluminium plates. Simulation models of the textile weave were developed on the meso- and macro-scale. The final correlation between impact simulation results on 3D textile-reinforced composite plates and impact test data was promising, highlighting the potential of such numerical simulation tools
Encadrement normatif et contractuel des pratiques de téléconsultation en clinique de première ligne
Jusqu'à la pandémie de la COVID-19, les services de téléconsultation offerts par des médecins omnipraticiens au Québec étaient fortement limités essentiellement parce qu'ils n'étaient pas rémunérés puisque non reconnus comme des actes médicaux assurables. Le décret du 16 mars 2020 , adopté dans le contexte d'urgence sanitaire, permet maintenant cette rémunération au même titre que la rémunération associée à la visite du patient en clinique. De nombreux avantages sont reconnus et associés à la téléconsultation en première ligne si cette téléconsultation est bien encadrée. Le présent projet vise à examiner les bonnes pratiques d'encadrement de la téléconsultation et à proposer des recommandations avant que ne soit négocié la prochaine entente de rémunération avec les médecins omnipraticiens. Nous recommandons notamment une formation obligatoire, une clarification législative quant au droit des assureurs privés de rembourser la téléconsultation et des modalités de rémunération variées en fonction du type de téléconsultation. Il nous appert enfin impératif de rapidement commander une étude détaillée sur les bénéfices et les coûts de la téléconsultation au Québec
EEG windowed statistical wavelet scoring for evaluation and discrimination of muscular artifacts
EEG recordings are usually corrupted by spurious extra-cerebral artifacts,
which should be rejected or cleaned up by the practitioner. Since manual
screening of human EEGs is inherently error prone and might induce
experimental bias, automatic artifact detection is an issue of importance.
Automatic artifact detection is the best guarantee for objective and clean results.
We present a new approach, based on the time–frequency shape of muscular
artifacts, to achieve reliable and automatic scoring. The impact of muscular
activity on the signal can be evaluated using this methodology by placing
emphasis on the analysis of EEG activity. The method is used to discriminate
evoked potentials from several types of recorded muscular artifacts—with a
sensitivity of 98.8% and a specificity of 92.2%. Automatic cleaning ofEEGdata
are then successfully realized using this method, combined with independent
component analysis. The outcome of the automatic cleaning is then compared
with the Slepian multitaper spectrum based technique introduced by Delorme
et al (2007 Neuroimage 34 1443–9)
Mixed crop–livestock farming systems: a sustainable way to produce beef? Commercial farms results, questions and perspectives
Interactions between animal enterprises and marketing strategies shape organic multispecies farming systems
One of the key ways to improve the sustainability of agricultural systems is through diversification, taking advantage of synergies between farm enterprises. Among diversified systems, multispecies livestock farms with at least two animal enterprises have rarely been studied. We explored 95 organic farms from six countries, accounting for the proportion of animal enterprises, sales management, workforce size, and work organization. The study reveals various types of interactions between animal enterprises. Complementarities were observed between ruminant and monogastric enterprises, particularly fertilizer transfer from monogastric manure to grasslands. Milk production was often associated with on-farm processing and short distribution channels, which enhanced farm viability and reduced its dependency on herd productivity. Eleven out of the 95 farms combined above-average production efficiency, on-farm processing, and the majority of sales in short distribution channels. Their labor productivity converged toward 22 livestock units per annual work unit, regardless of the number of workers. Combining farm structure; livestock production efficiency; social elements, such as the workforce; and sales management led us to distinguish four types of farms: (i) small and very autonomous grassland farms with on-farm processing and short distribution channels; (ii) dairy farms associated with a high-density pig or poultry enterprise, whose feed purchase contributes to high rates of cattle feeding self-sufficiency and stocking rate; (iii) large farms with an extensive, grassland beef enterprise associated with either sheep or monogastrics; and (iv) dairy sheep associated with goat or beef cattle on rangelands, with high added-value products enhancing salaries. This study highlights for the first time the diversity of organic multispecies livestock farms and how consistent patterns of interactions among farm structure, livestock management, sales management, and workforce management shape them. The results are a preliminary basis for designing policy interventions aiming to scale up organic farming and value social assets of diversified and small farms
Multi-species livestock farming
This CORE Organic Practice Abstract gives practical recommendations for multi-species livestock farming, which has the potential to improve the three dimensions of sustainability – economic viability for farmers, environmental soundness, and social acceptability – by being respectful of animals and humans, as long as locally relevant farming practices are implemented, especially an appropriate stocking rate during grazing
Magnetic Resonance Thermometry at 7T for Real-Time Monitoring and Correction of Ultrasound Induced Mild Hyperthermia
While Magnetic Resonance Thermometry (MRT) has been extensively utilized for non-invasive temperature measurement, there is limited data on the use of high field (≥7T) scanners for this purpose. MR-guided Focused Ultrasound (MRgFUS) is a promising non-invasive method for localized hyperthermia and drug delivery. MRT based on the temperature sensitivity of the proton resonance frequency (PRF) has been implemented in both a tissue phantom and in vivo in a mouse Met-1 tumor model, using partial parallel imaging (PPI) to speed acquisition. An MRgFUS system capable of delivering a controlled 3D acoustic dose during real time MRT with proportional, integral, and derivative (PID) feedback control was developed and validated. Real-time MRT was validated in a tofu phantom with fluoroptic temperature measurements, and acoustic heating simulations were in good agreement with MR temperature maps. In an in vivo Met-1 mouse tumor, the real-time PID feedback control is capable of maintaining the desired temperature with high accuracy. We found that real time MR control of hyperthermia is feasible at high field, and k-space based PPI techniques may be implemented for increasing temporal resolution while maintaining temperature accuracy on the order of 1°C
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