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Design considerations for cold formed lipped channel steel sections in composite slab systemsPretorius, Jock Milne 06 May 2008 (has links)
The use of lipped channel members as the reinforcing for composite beams in rib
and block type slab systems is advantageous due to its lightweight nature which
facilitates efficiently in construction. The main consideration in the design if such
composite members is the integrity of the shear bond at the concrete/ steel interface.
Premature de-bonding of the concrete from the steel results in an overall loss of
structural strength of the composite member. Certain guidelines are to be
established to facilitate in the design of such systems.
In this research project the shear bond strength of composite members using lipped
channel members is investigated by interrogating the results from three independent
research experiments. Design formulas from first principles are developed to more
easily benchmark the behaviour of such members. Complex and simple equations
are developed and the results obtained are compared to similar shear bond stresses
obtained from literature. A reasonably acceptable correlation is achieved.
A comparative study was also carried out between the various experimental beams
regarding vertical shear, flexural strength and short-term deflections. The purpose
was to ascertain what effect early shear bond failure has on these structural
properties. The formulas used to benchmark the results were the well known
formulas used for the design and evaluation of reinforced concrete members. The
results were tabulated showing the difference between the calculated and
experimental results.
As a result of the investigation the following conclusions seem justified :
The simple equations as developed for horizontal shear failure give
acceptable results which are within the range as given by more complex
equations.
The composite beam has a certain amount of reserve shear strength even
after the initial onset of horizontal shear failure.
iv
The reinforcing ratio, the concrete strength and the slenderness ratio of the
composite beam all have an influence on the level of horizontal stress failure.
The composite beams tend to fail at levels higher than that predicted by the
homogeneous shear equations but lower than the predicted flexural
equations. The parameters which influence this are again the reinforcing ratio,
the concrete strength and the slenderness ratio.
Once a composite beam has experienced shear bond failure the deflection
integrity of the beam is completely compromised.
The above conclusions show the designer that caution must be exercised when
using lipped channel members in rib and block slab systems.
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Foraging flexibility in the frog-eating bat, Trachops cirrhosusPage, Rachel Ann, 1973- 25 September 2012 (has links)
Males produce conspicuous advertisement signals to attract mates. These signals, however, often attract eavesdropping predators as well, so the benefit of obtaining a mate is balanced by the cost of an increased risk of predation. The evolution of sexual advertisement signals can be understood only through a thorough investigation of both predator and prey. The Neotropical bat, Trachops cirrhosus, feeds on frogs and uses frog mating calls to locate its prey. On the basis of frog calls alone, bats can assess which frogs are palatable and which are poisonous. The túngara frog, Physalaemus pustulosus, produces two types of calls, simple and complex. Both female frogs and frog-eating bats prefer complex calls to simple ones, and as a result, male frogs face opposing forces of sexual and natural selection. While there has been extensive study of mate choice behavior in the túngara frog, there has been comparatively little investigation of foraging behavior in the frog-eating bat. In my doctoral research, I investigate the sensory constraints and cognitive flexibility that shape foraging success in T. cirrhosus. Specifically, I address the following questions: (1) Are predator preferences for signal complexity influenced by localization performance? Do bats show better localization performance for complex calls than simple ones in silence, in noise, or in obstacles? (2) How fixed are predator associations for prey cues? Given novel foraging contexts, can predators rapidly track prey changes and alter pre-existing associations between prey cues and prey quality? (3) What mechanisms do predators use to learn about prey cues? Do social interactions play a role in prey acquisition behavior? My results show that while T. cirrhosus is limited by biophysical constraints in its ability to localize prey, within these constraints it shows surprising flexibility. It can rapidly alter associations between prey cues and prey quality, and can quickly acquire novel foraging behavior via social learning. Together these studies offer new insights on the role of eavesdropping predators in the evolution of their sexually advertising prey, and shed new light on the role of learning in foraging success. / text
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Avaliação sanitária da presença de doenças e caracterização dos padrões de caça de subsistência do queixada (Tayassu pecari) de vida livre na Amazônia Peruana / Serologic survey of disease and characterization of subsistence hunting patterns of white lipped peccaries (Tayassu pecari) populations in southwestern Amazon.Solorio, Monica Romero 08 July 2010 (has links)
A queixada (Tayassu pecari) é um ungulado de grande importância tanto no sentido ecológico pelo seu rol vital na estruturação e composição das comunidades vegetais e para a conservação de ecossistemas bem como no sentido sócio-econômico, por ser fonte de alimento e renda para os caçadores de subsistência na Amazônia Peruana. Não obstante varias pesquisas relataram seu declínio em decorrência de sobre extração e citando a presença de epidemias como um problema potencial. Com o objetivo de avaliar a presença de doenças em populações de queixadas de vida livre e caracterizar os padrões de caça nesta espécie foi desenvolvido o presente estudo durante os anos 2008 e 2009 na Região de Madre de Dios. Foram coletados 103 soros provenientes de animais abatidos para caça de subsistência de duas comunidades indígenas e de animais capturados no interior de três áreas naturais protegidas. Os resultados evidenciaram a presença de anticorpos às doenças de brucelose, leptospirose, toxoplasmose, existindo diferencia na prevalência entre os locais de coleta. Esta corresponde à primeira avaliação sanitária de queixadas na Amazônia Peruana. Como parte complementar foram monitoradas as atividades de caça dos caçadores de subsistência das duas comunidades para caracterizar a área de caça utilizada, a produtividade, a pressão de caça e avaliar se a extração era sustentável. A caça das queixadas aparenta ser sustentável e a população caçada esta sendo adequadamente extraída em termos de sustentabilidade em longo prazo. / The peccary (Tayassu pecari) holds an important place in the Amazonian ecosystem. As seed dispersers they have measurable effects on their habitat, partly guiding structure and composition of the vegetation community. Additionally, their socio-economic role is unsurpassed as one of the most important sources of bushmeat for subsistence hunters in the Peruvian Amazon. Various studies have alarmingly reported the decline of several populations, possibly a result of overextraction due to hunting. However, passing reference was also made to disease and its possible role in population fluctuations. The following study, taking place in Madre de Dios during 2008 and 2009, evaluates the presence of disease in three wild peccary populations. It is the first of its kind in the Peruvian Amazon. A complimentary study characterizing human hunting patterns of peccaries in two indigenous communities is also reported. Exactly 103 serum samples from hunted or live-captured animals were obtained for the study. The results indicate the presence of antibodies to brucelose, leptospirose, and toxoplasmose, in wild populations, the distribution of which is not equal among the three sites. The complimentary study characterizes human hunting patterns of peccaries, focusing on the delimitation of hunting grounds and the quantification of hunting pressure, annual animal productivity, and sustainability of hunting activities. Hunting pressure was found to be well within the limits of sustainability.
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Ocorrência e detecção molecular de espécies de Mycobacterium, e dos genes de virulência vapA, vapB e VapN em linhagens de Rhodococcus equi, isoladas de linfonodos de taiassuídeos de cativeiro / Occurrence and molecular detection of Mycobacterium species, and the virulence-associated proteins (vapA, vapB and vapN genes) in strains of Rhodococcus equi, isolated from the lymph nodes of captive Tayassuidae speciesMorais, Amanda Bonalume Cordeiro de [UNESP] 14 July 2017 (has links)
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Previous issue date: 2017-07-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Foram investigadas, neste estudo, proteínas associadas à virulência (genes vapA, vapB e vapN) das espécies de Rhodococcus equi e Micobactérias isoladas de 330 linfonodos de catetos (Tayassu tajacu) e queixadas (Tayassu pecari) destinados ao consumo humano. Trinta e seis (10,9%) linhagens de R. equi foram isoladas, 3,3% (11/330) dos linfonodos de queixadas e 7,6% (25/330) dos catetos. Entre os 11 isolados de R. equi das queixadas, 90,9% (n=10/11) foram obtidos de linfonodos mesentéricos e apenas 9,1% (n=1/10) de linfonodo mediastínico. Nos 25 isolados de R. equi dos catetos, 40,0% (10/25) foram obtidos de linfonodos mesentéricos, 36,0% (9/25) de submandibulares e 24,0% (6/25) de mediastínicos. Não foram identificados genes vapA, vapB e vapN entre os isolados de R. equi. Foi isolado Mycobacterium sp. de 3,03% (10/330) do total de linfonodos. Entre os 10 isolados de micobactérias, 60% (n=6/10) dos linfonodos eram de queixadas e 40% (4/10) de catetos. Dez espécies de Mycobacterium foram detectadas por PCR-PRA, com predominância de M. avium tipo 1. O sequenciamento dos genes hsp65 e rpob revelaram micobactérias saprófitas (M. sinense, M. kumamotonense) e potencialmente patogênicas (M. colombiense, M. intracellulare) para humanos e animais. Esta é a primeira descrição de R. equi e / ou espécies de micobactérias identificadas nos linfonodos de espécimes de Tayassuideos. Apesar da ausência de genes Vap, a identificação de R. equi, bem como de micobactérias não tuberculosas e saprófitas, destacam o risco de transmissão desses patógenos das espécies de Tayassuideos para humanos por meio de carne ou produtos à base de carne contaminados com conteúdo de linfonodos, uma vez que R. equi sem plasmídeo de virulência e as espécies de micbactérias descritas aqui já foram relatadas como causas de infecções pulmonares e extrapulmonares em seres humanos imunocompetentes e imunocomprometidos. / Virulence-associated proteins (vapA, vapB and vapN genes) of Rhodococcus equi and Mycobacterium species isolated from 330 lymph nodes of collared peccaries (Tayassu tajacu) and white-lipped peccaries (Tayassu pecari) intended for human consumption were investigated. Thirty-six (10.9%) R. equi strains were isolated, 3.3% (11/330) from white-lipped peccary and 7.6% (25/330) of collared peccary lymph nodes. Among the 11 isolates of R. equi of the white-lipped peccaries, 90.9% (n = 10/11) were obtained from mesenteric lymph nodes and only 9.1% (n = 1/10) of the mediastinal lymph node. In the 25 isolates of R. equi obtained from collared peccaries, 40.0% (10/25) were recovered from mesenteric lymph nodes, 36% (9/25) from submandibular, and 24.0% (6/25) from mediastinal ones. No vapA, vapB, and vapN genes (plasmidless type) were identified among R. equi isolates. Mycobacterium sp. was isolated in 3.03% (10/330) of all lymph nodes analyzed. Among the 10 mycobacterial isolates, 60% (n = 6/10) were from white-lipped peccary, and 40% (4/10) from collared peccary lymph nodes. Ten Mycobacterium species were detected by PCR-PRA, with predominance of M. avium type 1. Sequencing of hsp65 and rpob genes revealed mycobacteria that were saprophytic (M. sinense, M. kumamotonense) and potentially pathogenic (M. colombiense, M. intracellulare) to humans and animals. To our knowledge, this is the first description of R. equi and/or mycobacteria species identified in the lymph nodes of Tayassuid specimens. Despite the absence of Vap genes, the identification of R. equi, as well as nontuberculous and saprophytic mycobacteria highlight the risk of transmission of these pathogens from Tayassuidae species to humans by means of meat or meat products contaminated with lymph node contents, since R. equi plasmidless type and mycobacterial species described here have been reported as causes of pulmonary and extrapulmonary infections both in immunocompetent and immunocompromised humans.
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Avaliação sanitária da presença de doenças e caracterização dos padrões de caça de subsistência do queixada (Tayassu pecari) de vida livre na Amazônia Peruana / Serologic survey of disease and characterization of subsistence hunting patterns of white lipped peccaries (Tayassu pecari) populations in southwestern Amazon.Monica Romero Solorio 08 July 2010 (has links)
A queixada (Tayassu pecari) é um ungulado de grande importância tanto no sentido ecológico pelo seu rol vital na estruturação e composição das comunidades vegetais e para a conservação de ecossistemas bem como no sentido sócio-econômico, por ser fonte de alimento e renda para os caçadores de subsistência na Amazônia Peruana. Não obstante varias pesquisas relataram seu declínio em decorrência de sobre extração e citando a presença de epidemias como um problema potencial. Com o objetivo de avaliar a presença de doenças em populações de queixadas de vida livre e caracterizar os padrões de caça nesta espécie foi desenvolvido o presente estudo durante os anos 2008 e 2009 na Região de Madre de Dios. Foram coletados 103 soros provenientes de animais abatidos para caça de subsistência de duas comunidades indígenas e de animais capturados no interior de três áreas naturais protegidas. Os resultados evidenciaram a presença de anticorpos às doenças de brucelose, leptospirose, toxoplasmose, existindo diferencia na prevalência entre os locais de coleta. Esta corresponde à primeira avaliação sanitária de queixadas na Amazônia Peruana. Como parte complementar foram monitoradas as atividades de caça dos caçadores de subsistência das duas comunidades para caracterizar a área de caça utilizada, a produtividade, a pressão de caça e avaliar se a extração era sustentável. A caça das queixadas aparenta ser sustentável e a população caçada esta sendo adequadamente extraída em termos de sustentabilidade em longo prazo. / The peccary (Tayassu pecari) holds an important place in the Amazonian ecosystem. As seed dispersers they have measurable effects on their habitat, partly guiding structure and composition of the vegetation community. Additionally, their socio-economic role is unsurpassed as one of the most important sources of bushmeat for subsistence hunters in the Peruvian Amazon. Various studies have alarmingly reported the decline of several populations, possibly a result of overextraction due to hunting. However, passing reference was also made to disease and its possible role in population fluctuations. The following study, taking place in Madre de Dios during 2008 and 2009, evaluates the presence of disease in three wild peccary populations. It is the first of its kind in the Peruvian Amazon. A complimentary study characterizing human hunting patterns of peccaries in two indigenous communities is also reported. Exactly 103 serum samples from hunted or live-captured animals were obtained for the study. The results indicate the presence of antibodies to brucelose, leptospirose, and toxoplasmose, in wild populations, the distribution of which is not equal among the three sites. The complimentary study characterizes human hunting patterns of peccaries, focusing on the delimitation of hunting grounds and the quantification of hunting pressure, annual animal productivity, and sustainability of hunting activities. Hunting pressure was found to be well within the limits of sustainability.
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Compression Stability of High Strength Steel Sections with Low Strain-HardeningYANG, Demao January 2003 (has links)
Thin-walled steel sections made from high strength thin cold-reduced G550 steel to Australian Standard AS 1397-1993 under compression are investigated experimentally and theoretically in this thesis. This thesis describes three series of compression tests performed on box-section stub columns, box-section long columns and lipped channel section columns cold-formed from high strength steel plates in 0.42 mm or 0.60 mm thickness with nominal yield stress of 550 MPa. The tests presented in this thesis formed part of an Australian Research Council research project entitled: Compression Stability of High Strength Steel Sections with Low Strain-Hardening. For the fix-ended stub column tests, a total of 94 lipped-square and hexagonal section stub columns were tested to study the influence of low strain hardening of G550 steel on the compressive section capacities of the column members. For the pin-ended long column tests, a total of 28 box-section columns were tested to study the stability of members with sections which undergo local instability at loads significantly less than the ultimate loads. For the fix-ended lipped channel section columns, a total of 21 stub and long columns were tested to study the failure resulting from local and distortional buckling with interaction between the modes. A numerical simulation on the three series of tests using the commercial finite element computer program ABAQUS is also presented as part of this thesis. The post-buckling behaviour of thin-walled compression members is investigated. The effect of changing variables, such as geometric imperfections and end boundary conditions is also investigated. The ABAQUS analysis gives accurate simulations of the tests and is in good agreement to the experimental results. Theoretical studies using finite strip methods are presented in this thesis to investigate the buckling behaviour of cold-formed members in compression. The theoretical studies provide valuable information on the local and distortional buckling stresses for use in the interaction buckling studies. The finite strip models used are the semi-analytical and spline models. As expected for the stub columns tests, the greatest effect of low strain hardening was for the stockier sections where material properties play an important role. For the more slender sections where elastic local buckling and post-local buckling are more important, the effect of low strain hardening does not appear to be as significant. The pin-ended and fix-ended long column tests show that interaction, which is between local and overall buckling in the box sections, and between local and distortional buckling in the open channel sections, has a significant effect on their member capacities. The results of the successful column tests and ABAQUS simulation have been compared with the design procedures in the Australian & New Zealand Standard for Cold-Formed Steel Structures AS&NZS 4600 and the North American Specification for Cold-Formed Steel Structural Members prepared by the American Iron and Steel Institute. The stub column tests show that the current design rules give too conservative predictions on the compressive section capacities of the column members; whereas the long column tests show that the current column design rules are unconservative if used in their current form for G550 steel. Three design proposals are presented in this thesis to account for the effects of high strength thin steels on the section and member capacities.
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Compression Stability of High Strength Steel Sections with Low Strain-HardeningYANG, Demao January 2003 (has links)
Thin-walled steel sections made from high strength thin cold-reduced G550 steel to Australian Standard AS 1397-1993 under compression are investigated experimentally and theoretically in this thesis. This thesis describes three series of compression tests performed on box-section stub columns, box-section long columns and lipped channel section columns cold-formed from high strength steel plates in 0.42 mm or 0.60 mm thickness with nominal yield stress of 550 MPa. The tests presented in this thesis formed part of an Australian Research Council research project entitled: Compression Stability of High Strength Steel Sections with Low Strain-Hardening. For the fix-ended stub column tests, a total of 94 lipped-square and hexagonal section stub columns were tested to study the influence of low strain hardening of G550 steel on the compressive section capacities of the column members. For the pin-ended long column tests, a total of 28 box-section columns were tested to study the stability of members with sections which undergo local instability at loads significantly less than the ultimate loads. For the fix-ended lipped channel section columns, a total of 21 stub and long columns were tested to study the failure resulting from local and distortional buckling with interaction between the modes. A numerical simulation on the three series of tests using the commercial finite element computer program ABAQUS is also presented as part of this thesis. The post-buckling behaviour of thin-walled compression members is investigated. The effect of changing variables, such as geometric imperfections and end boundary conditions is also investigated. The ABAQUS analysis gives accurate simulations of the tests and is in good agreement to the experimental results. Theoretical studies using finite strip methods are presented in this thesis to investigate the buckling behaviour of cold-formed members in compression. The theoretical studies provide valuable information on the local and distortional buckling stresses for use in the interaction buckling studies. The finite strip models used are the semi-analytical and spline models. As expected for the stub columns tests, the greatest effect of low strain hardening was for the stockier sections where material properties play an important role. For the more slender sections where elastic local buckling and post-local buckling are more important, the effect of low strain hardening does not appear to be as significant. The pin-ended and fix-ended long column tests show that interaction, which is between local and overall buckling in the box sections, and between local and distortional buckling in the open channel sections, has a significant effect on their member capacities. The results of the successful column tests and ABAQUS simulation have been compared with the design procedures in the Australian & New Zealand Standard for Cold-Formed Steel Structures AS&NZS 4600 and the North American Specification for Cold-Formed Steel Structural Members prepared by the American Iron and Steel Institute. The stub column tests show that the current design rules give too conservative predictions on the compressive section capacities of the column members; whereas the long column tests show that the current column design rules are unconservative if used in their current form for G550 steel. Three design proposals are presented in this thesis to account for the effects of high strength thin steels on the section and member capacities.
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Increasing ecological realism in conservation network design / a case study in Belize and an evaluation of global satellite telemetry for connectivity researchHofman, Maarten 15 May 2017 (has links)
No description available.
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Traitement de l'arthrose canine : étude d'efficacité d'une diète riche en moule verte (Perna canaliculus) et validité des méthodes cliniques d'évaluation de l'effet traitementBichot, Sylvain 09 1900 (has links)
Introduction: L’arthrose est une maladie fréquente chez le chien. Même si des traitements palliatifs ont prouvé leur efficacité pour soulager les signes cliniques associés, aucun n’a permis de restaurer la structure des cartilages ou la fonction des patients. De nouvelles modalités de traitement sont proposées mais très peu d’évidences existent quant à leur efficacité. Un problème récurrent pour apporter plus d’évidence est le manque d’outils d’évaluation dûment validés.
Objectif: Evaluer l’efficacité d’une diète contenant de la moule verte, ainsi que la validité de différentes méthodes pour évaluer les effets de ce traitement sur la condition arthrosique de chiens de propriétaire.
Méthodes: Une étude prospective croisée contrôlée en aveugle a été conduite sur 30 chiens de propriétaires. Leur condition était stable et non traitée. Ils ont reçu une diète contrôle pendant 30 jours puis la diète thérapeutique pendant 60 jours. A J0 (inclusion), J30 (fin de la période contrôle) et J90 (fin du traitement), les concentrations plasmatiques en acides gras ω–3 (EPA et DHA), le pic de force verticale (PVF – critère de référence), un questionnaire multifactoriel standardisé (MFQ), et la conductance électrodermique (EDA) ont été mesurés. Deux fois par semaine, les propriétaires remplissaient un questionnaire sur la fonction spécifique à leur animal (CODI). L’activité locomotrice (actimétrie) a été enregistrée en continu sur 7 chiens.
Résultats: Aucun effet secondaire n’a été documenté excepté une augmentation du poids des chiens durant la période traitement. La localisation -thoracique ou pelvienne- du membre étudié et le poids ont interagi avec PVF. Les taux d’EPA et DHA ont augmenté durant la période traitement (p=0.026 et p<0.001, respectivement), tout comme PVF corrigé pour l’effet du poids et de la localisation du membre (p=0.003). La validité technique de PVF a été vérifiée. La validité technique et selon-critère du CODI ont été vérifiées. MFQ n’a pas montré d’homogénéité suffisante entre ses différents composants, bien que les résultats du composite convergent partiellement avec PVF. L’EDA n’a pas montré de validité technique suffisante. L’actimétrie a montré une validité technique satisfaisante ainsi que des résultats convergeant avec ceux de PVF.
Conclusions: La méthode choisie comme référence a montré un effet bénéfique de la diète testée et sa validité technique a été vérifiée. À la fois, CODI et l’actimétrie ont été validés. La validité d’EDA et de MFQ a été remise en question. L’actimétrie a donné des résultats prometteurs, probablement complémentaires de PVF. / Background: Osteoarthritis is a frequent disease in dogs. Even though palliative treatments have been proven efficient in alleviating the associated clinical signs, none restored structure of the cartilage or complete function of the patients. New modalities have been proposed but evidence of their effects is weak. The weakness of the evidence is partially explained by the rare validation of the methods of assessment.
Objective: To assess the efficacy of a diet containing green-lipped mussel, as well as technical and concurrent validity of different assessment instruments for measuring the effects of a treatment on the osteoarthritic condition of client-owned dogs.
Methods: A prospective blinded controlled crossover study was performed on 30 client-owned dogs, suffering from stable and non-treated osteoarthritis. They received a 30-day control diet, followed by a 60-day experimental therapeutic diet. Punctual methods of assessment included Peak of Vertical Force (PVF – “gold standard”), standardized MultiFactorial Questionnaire (MFQ) and ElectroDermal Activity (EDA), and were assessed at D0 (inclusion), D30 (end of control) and D90 (end of treatment). Twice a week, the owners completed a case-specific functional (CODI) assessment. Motor activity (actimetry) was continuously recorded on seven dogs.
Results: No side effects were observed except the dogs gained weight during the second period. The location of the affected limb, thoracic or pelvic, as well as the body weight interfered with PVF. Both EPA and DHA increased during treatment (p=0.026 and p<0.001, respectively), as well as PVF after adjustment for location of the limb and weight (p=0.003). The technical validity of PVF was confirmed. Technical and concurrent validity of CODI were documented. The reliability of MFQ was insufficient since the individual components did not show homogeneity. However, concurrent validity of the composite scale was partially noted. Preliminary results proved the technical and concurrent validity of actimetry.
Conclusions and clinical relevance: The “gold standard” method, PVF, showed a beneficial effect of the tested diet and its technical validity was verified. CODI and actimetry have been validated. The validity of MFQ and EDA has been questioned. Actimetry showed promising results, possibly complementing PVF.
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Traitement de l'arthrose canine : étude d'efficacité d'une diète riche en moule verte (Perna canaliculus) et validité des méthodes cliniques d'évaluation de l'effet traitementBichot, Sylvain 09 1900 (has links)
Introduction: L’arthrose est une maladie fréquente chez le chien. Même si des traitements palliatifs ont prouvé leur efficacité pour soulager les signes cliniques associés, aucun n’a permis de restaurer la structure des cartilages ou la fonction des patients. De nouvelles modalités de traitement sont proposées mais très peu d’évidences existent quant à leur efficacité. Un problème récurrent pour apporter plus d’évidence est le manque d’outils d’évaluation dûment validés.
Objectif: Evaluer l’efficacité d’une diète contenant de la moule verte, ainsi que la validité de différentes méthodes pour évaluer les effets de ce traitement sur la condition arthrosique de chiens de propriétaire.
Méthodes: Une étude prospective croisée contrôlée en aveugle a été conduite sur 30 chiens de propriétaires. Leur condition était stable et non traitée. Ils ont reçu une diète contrôle pendant 30 jours puis la diète thérapeutique pendant 60 jours. A J0 (inclusion), J30 (fin de la période contrôle) et J90 (fin du traitement), les concentrations plasmatiques en acides gras ω–3 (EPA et DHA), le pic de force verticale (PVF – critère de référence), un questionnaire multifactoriel standardisé (MFQ), et la conductance électrodermique (EDA) ont été mesurés. Deux fois par semaine, les propriétaires remplissaient un questionnaire sur la fonction spécifique à leur animal (CODI). L’activité locomotrice (actimétrie) a été enregistrée en continu sur 7 chiens.
Résultats: Aucun effet secondaire n’a été documenté excepté une augmentation du poids des chiens durant la période traitement. La localisation -thoracique ou pelvienne- du membre étudié et le poids ont interagi avec PVF. Les taux d’EPA et DHA ont augmenté durant la période traitement (p=0.026 et p<0.001, respectivement), tout comme PVF corrigé pour l’effet du poids et de la localisation du membre (p=0.003). La validité technique de PVF a été vérifiée. La validité technique et selon-critère du CODI ont été vérifiées. MFQ n’a pas montré d’homogénéité suffisante entre ses différents composants, bien que les résultats du composite convergent partiellement avec PVF. L’EDA n’a pas montré de validité technique suffisante. L’actimétrie a montré une validité technique satisfaisante ainsi que des résultats convergeant avec ceux de PVF.
Conclusions: La méthode choisie comme référence a montré un effet bénéfique de la diète testée et sa validité technique a été vérifiée. À la fois, CODI et l’actimétrie ont été validés. La validité d’EDA et de MFQ a été remise en question. L’actimétrie a donné des résultats prometteurs, probablement complémentaires de PVF. / Background: Osteoarthritis is a frequent disease in dogs. Even though palliative treatments have been proven efficient in alleviating the associated clinical signs, none restored structure of the cartilage or complete function of the patients. New modalities have been proposed but evidence of their effects is weak. The weakness of the evidence is partially explained by the rare validation of the methods of assessment.
Objective: To assess the efficacy of a diet containing green-lipped mussel, as well as technical and concurrent validity of different assessment instruments for measuring the effects of a treatment on the osteoarthritic condition of client-owned dogs.
Methods: A prospective blinded controlled crossover study was performed on 30 client-owned dogs, suffering from stable and non-treated osteoarthritis. They received a 30-day control diet, followed by a 60-day experimental therapeutic diet. Punctual methods of assessment included Peak of Vertical Force (PVF – “gold standard”), standardized MultiFactorial Questionnaire (MFQ) and ElectroDermal Activity (EDA), and were assessed at D0 (inclusion), D30 (end of control) and D90 (end of treatment). Twice a week, the owners completed a case-specific functional (CODI) assessment. Motor activity (actimetry) was continuously recorded on seven dogs.
Results: No side effects were observed except the dogs gained weight during the second period. The location of the affected limb, thoracic or pelvic, as well as the body weight interfered with PVF. Both EPA and DHA increased during treatment (p=0.026 and p<0.001, respectively), as well as PVF after adjustment for location of the limb and weight (p=0.003). The technical validity of PVF was confirmed. Technical and concurrent validity of CODI were documented. The reliability of MFQ was insufficient since the individual components did not show homogeneity. However, concurrent validity of the composite scale was partially noted. Preliminary results proved the technical and concurrent validity of actimetry.
Conclusions and clinical relevance: The “gold standard” method, PVF, showed a beneficial effect of the tested diet and its technical validity was verified. CODI and actimetry have been validated. The validity of MFQ and EDA has been questioned. Actimetry showed promising results, possibly complementing PVF.
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