Field trials to evaluate the efficacy of mash feed to reduce Salmonella shedding in swine

The objective of this study owas to evaluate the effect of corn based mash feed as a preharvest intervetion strategy to reduce shedding in pigs herds contaminated by Salmonella spp. In this study, three nurseries previously found contaminated by Salmonella in successive production cycles were selected to evaluate the effect of mash feed

Régionalisation des habitats humides du Québec forestier méridional

Malgré l'accroissement des pressions résultant de l'exploitation forestière, minière et hydroélectrique, et malgré une volonté générale de protéger et de conserver les milieux humides, peu d'efforts de recherche leur ont été consacrés, notamment en milieu forestier. Même si nous avons une bonne connaissance de l'écologie de ces milieux, aucune étude concernant la quantification et la régionalisation des milieux humides n'a été réalisée à l'échelle de la province de Québec. Une revue de littérature a démontré que les systèmes de classification eux-mêmes pouvaient être une des causes de l'absence d'une base de données provinciale. Bien que les différentes classifications soient scientifiquement irréprochables, elles sont difficilement utilisables avec des méthodes de télédétection puisqu'elles nécessitent une validation terrain. Nous avons réalisé une étude sur la distribution à petite échelle des milieux humides du Québec forestier (540 000 km2). Les objectifs poursuivis étaient la quantification de différents types de milieux humides, le découpage de l'aire d'étude en paysages-types, l'étude de la relation entre la distribution des milieux humides et certaines variables environnementales, et l'évaluation de la capacité des classifications écologiques terrestres à intégrer la diversité des milieux humides. Nous avons classifié les milieux humides sur 456 feuillets cartographiques écoforestiers répartis systématiquement selon un système reconnaissant 17 types de milieux humides et aquatiques et en avons quantifié la couverture par feuillet. Les 17 types se distinguent par le régime trophique, le sol, la végétation et leur connexion au système hydrographique. Ils se regroupent en trois classes, soit les milieux aquatiques, les dénudés humides et les marécages. Par des analyses en composantes principales et de groupement, les paysages-types ont été reconnus et caractérisés en groupant les feuillets selon leur similarité en termes de milieux humides. L'analyse de redondance partielle a permis d'étudier le pouvoir explicatif des variables environnementales quant à la distribution des milieux humides, puis l'analyse discriminante a été employée pour l'étude de la relation entre les classifications terrestres et la distribution des milieux humides. Les résultats ont démontré l'hétérogénéité spatiale des milieux aquatiques et humides, qui représentent respectivement 10,3% et 11,7% de la superficie classifiée. La variabilité spatiale a été confirmée par l'identification de six paysages-types se regroupant en trois catégories (paysages-types humides, secs et anthropiques). La présence de ce dernier évoque l'ampleur de l'empreinte humaine sur les habitats aquatiques. La variabilité dans la couverture de milieux humides est fortement liée aux variables environnementales. La géomorphologie et la géologie ont un pouvoir explicatif significativement plus grand que le climat, ce qui explique que le cadre écologique de référence, basé sur la géologie, intègre davantage la diversité des milieux humides que le système de classification écologique basé sur le climat. Bien que les projets de conservation des milieux humides devraient être basés sur un cadre écologique qui leur est propre, il demeure que l'utilisation de cadres écologiques basés sur la géologie et la géomorphologie est une alternative intéressante pour la planification de la conservation des milieux humides dans les endroits où une régionalisation des milieux humides est inexistante

Finite element study of hyperstructure systems with modular light‐frame construction in high‐rise buildings

To answer both the growth of the world's urban population and the climate changes, new structural systems with high prefabrication levels and renewable materials need to be developed. A novel structural system that could enable the use of modular light‐frame construction in high‐rise buildings was modeled and analyzed. This system was achieved by having a hyperstructure carrying the loads of four‐story light‐frame superposed substructures. Two 20‐story hyperstructures, one using glulam and another one using reinforced concrete, were designed according to the 2015 National Building Code of Canada and compared. A simplified model for the light‐frame modules according to the CSA O86‐19 was proposed. The interaction between both systems and the impact on the substructures were analyzed. The results of the response spectrum analysis and dynamic wind analysis show that, with a glulam hyperstructure, modules could be connected to the columns and the floors or only to the floors. With a concrete hyperstructure, the modules must be connected to the columns and the cores. For both systems, the design of shearwalls on the short side of the modules is governed by the lateral deformation imposed by seismic forces, while the design of shearwalls on the long side of the modules is governed by the vertical deformation of the primary beams under gravity loads. Standard shearwall assemblies are sufficient to resist the shear induced by gravitational, wind and seismic loads. The analysis indicates that the system could be viable, but more research should be especially performed on the connections between the substructures and the hyperstructure

Effect of mash feed on swine intestinal microflora and non-specific immune response.

Pelleting of feed was recommended in the past to reduce the risk of introduction of Salmonella in swine herds. However it was shown more recently that consumption of pelleted feed was associated with an increased probability of seropositivity Furthermore, several studies showed that the prevalence of Salmonella is decreased when mash feed is used. The objective of this study was to evaluate the effect of mash feed as a pre-harvest intervention strategy to prevent Salmonella colonization, to mod1fy of intestinal microflora and to stimulate of the immune system in swine

Impact of a reinforcement treatment with acrylate impregnation on the mechanical behavior of black spruce as connector member.

As a previous study has shown, it is possible to increase by 50% the dowel bearing strength of black spruce with an acrylate formulation applied by impregnation. Three diameters of bolts and two orientations of loading were included in this study. The effect of treatment on the dowel-bearing strength appeared to increase while the diameter of bolt decreased. The orientation of loading was significant as the treatment had a major impact in the parallel to grain direction and no impact in the perpendicular direction. With the digital image correlation analysis, an expanded strain field perpendicular to the load direction was observed. The superior embedding capacity would help to reduce the dimensions of the timbers as well as the number of connections required in the building design. With an increase of ductility, wood connections show a safer yielding behavior

Heat transfer behavior of green roof systems under fire condition : a numerical study

Currently, green roof fire risks are not clearly defined. This is because the problem is still not well understood, which raises concerns. The possibility of plants catching fire, especially during drought periods, is one of the reasons for necessary protection measures. The potential fire hazard for roof decks covered with vegetation has not yet been fully explored. The present study analyzes the performance of green roofs in extreme heat conditions by simulating a heat transfer process through the assembly. The main objective of this study was to determine the conditions and time required for the roof deck to reach a critical temperature. The effects of growing medium layer thickness (between 3 and 10 cm), porosity (0.5 to 0.7), and heating intensity (50, 100, 150, and 200 kW/m2 ) were examined. It was found that a green roof can protect a wooden roof deck from igniting with only 3 cm of soil coverage when exposed to severe heat fluxes for at least 25 minutes. The dependency of failure time on substrate thickness decreases with increasing heating load. It was also found that substrate porosity has a low impact on time to failure, and only at high heating loads

Flammability characteristics of green roofs

Assessing the fire risk of vegetated roofs includes the determination of their possible contribution to fire. Green roof components such as plants and growing media are organic materials and present a fuel that can catch and support the spread of fire. The flammability characteristics of these components were analyzed and compared to a typical roof covering. Growing media with 15% of organic matter were tested using cone calorimeter apparatus. The fuel load and heat release rate of the growing media were measured in both moist (30%) and dry conditions. It was observed that growing media in a moist condition do not present a fire risk, reaching a maximum heat release rate of 33 kW/m2. For dry substrates, a peak heat release rate of 95 kW/m2 was recorded in the first minute, which then rapidly decreased to 29 kW/m2 in the second minute. Compared to a typical bitumen roof membrane, the green roof showed a better fire performance. The literature data report more severe results for plant behavior, reaching peak heat release rates (HRRs) of 397 kW/m2 for dried and 176 kW/m2 for a green material. However, a rapid decrease in HRR to much lower values occurs in less than 2 min. The results also show that extensive and intensive types of green roofs present 22% and 95% of the additional fire load density when installed on a modified bitumen membrane, 19.7 and 85.8 MJ/m2, respectively

Impact of Information Technology Multitasking on Hedonic Experience

This study investigates the impact of information technology (IT) multitasking on multisensory hedonic experience. Existing literature extensively studies the impact of IT multitasking on user experience in a professional context but still lacks insight regarding this influence in a hedonic context. This study contributes to the literature by examining how technology can alter pleasure induced by hedonic activities. In a context of engaged IT interaction along with multisensory music listening, we hypothesize that the multisensory factor positively influences emotional reaction. We also hypothesize that IT interaction will degrade the hedonic experience. We conducted a multi-method experiment using both explicit (questionnaires) and implicit (automatic facial analysis, and electrodermal activity) measures of emotional reactions. Results support our hypotheses and highlight the importance of avoiding multitasking with technology during passive hedonic activities for better experience. Future research may examine IT multitasking’s influence on active hedonic activities

Strength and Behavior of Spruce Pine Glulam Timber Moment Connections Using Glued-In Steel Rods

This paper presents experimental testing on glulam beam–column moment-resisting connections using glued-in rods (GiRod) and compares the results with model predictions. Three connection geometries and varying numbers of rods and member size were tested and compared. This experiment will be helpful in grounding research by bringing in new experimental results and proposing an innovative experimentation method. Experimental results showed the high efficiency of glued-in rod connections to transfer loads and bending moment between spruce pine glulam timber members. The observed limit states of the connections were failed steel rods in ductile tensile yielding or wood splitting around the anchorage installed perpendicularly to the grain in the column. It was found that the tested connections behaved as a semirigid moment-resisting connection and exhibited a ductile failure mode when wood splitting was avoided by design. Comparison of experimental results with model predictions showed good agreement, with a deviation under 15% for the moment capacity of the connection

Pull-out strength of glued-in steel rod perpendicular to the grain in spruce-pine glulam timber

This study presents pull-out tests of glued-in steel rod installed perpendicularly to the grain in Spruce-Pine glulam timber. The tested specimens indicate that the embedded length and the steel grade influence the anchorage behaviour and capacity. Results showed that a well design anchor can exhibit a ductile failure mode. Experimental results are also compared to theoretical models and to pull-out strength of glued-in steel rod parallel to the grain to investigate the relation between these pull-out strength capacities