804 resultados para Wood longitudinal modulus of elasticity
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This paper investigates the effects of women‘s labour force participation on fertility, as well as the effects of the combined labour force participation of both members of a couple. It specifically focuses on such dimensions as unemployment, earnings, temporary contracts and part-time jobs, and it shows that their effects differ in accordance with national institutions and labour market regulations. Event-history methods and a longitudinal sample of the European Community Household Panel are used in the analyses, concerning the years 1993-2000. The results show that labour market insecurity of one or both members of a couple has a particularly strong impact in reducing birth rates in the Southern European countries studied. The more conventional model of men’s employment combined with housewifery has a positive impact on second or higher order births in United Kingdom, Spain and Italy, while in Denmark the effect is the opposite. These differences are consistent with different national models of combining parental responsibilities and participation by gender across the life course.
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Formica lugubris and E paralugubris are sympatric sibling species of wood ants, both of which are widely distributed in Switzerland. Until 1996 they were considered the same species, E lugubris. To investigate whether the two species can be distinguished based on discrimination cues used by the workers we used the pupa-carrying test first introduced by Rainer Rosengren. In this test workers of discriminator colonies are faced with two kinds of pupae and their preferences for one of the types are recorded based on differential retrieval. Interspecific comparisons showed that ants preferred conspecific worker pupae to those of the sibling species regardless whether the pupae were con-colonial or hetero-colonial. Hence, this test can be used as a taxonomic tool to identify wood ants hardly distinguishable by morphological characters. In intraspecific comparisons the highly polygynous (many queens per colony) E paralugubris, the polygynous form of E lugubris and the monogynous (single queen per nest) to weakly polygynous form of E lugubris expressed different trends in their preference behaviour (with nestmate recognition in 14%, 20% and 31% of replicates, respectively). Only F paralugubris presented no significant nestmate recognition.
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Load transfer across transverse joints has always been a factor contributing to the useful life of concrete pavements. For many years, round steel dowels have been the conventional load transfer mechanism. Many problems have been associated with the round steel dowels. The most detrimental effect of the steel dowel is corrosion. Repeated loading over time also damages joints. When a dowel is repeatedly loaded over a long period of time, the high bearing stresses found at the top and bottom edge of a bar erode the surrounding concrete. This oblonging creates multiple problems in the joint. Over the past decade, Iowa State University has performed extensive research on new dowel shapes and materials to mitigate the effects of oblonging and corrosion. This report evaluates the bearing stress performance of six different dowel bar types subjected to two different shear load laboratory test methods. The first load test is the AASHTO T253 method. The second procedure is an experimental cantilevered dowel test. The major objective was to investigate and improve the current AASHTO T253 test method for determining the modulus of dowel support, k0. The modified AASHTO test procedure was examined alongside an experimental cantilever dowel test. The modified AASHTO specimens were also subjected to a small-scale fatigue test in order to simulate long-term dowel behavior with respect to concrete joint damage. Loss on ignition tests were also performed on the GFRP dowel specimens to determine the resin content percentage. The study concluded that all of the tested dowel bar shapes and materials were adequate with respect to performance under shear loading. The modified AASHTO method yielded more desirable results than the ones obtained from the cantilever test. The investigators determined that the experimental cantilever test was not a satisfactory test method to replace or verify the AASHTO T253 method.
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We present the first parasitological, molecular and longitudinal analysis of an isolated outbreak of malaria. This outbreak occurred on Santiago Island (Republic of Cabo Verde), a region where malaria is hypoendemic and controlled, and thus the population is considered non-immune. Blood samples were collected from the inhabitants over 1 month and during cross-sectional surveys in the following year. The presence and nature of the parasites was determined by PCR. Plasmodium falciparum was the only species detected. Genetic analysis revealed that the circulating parasites were genetically homogeneous, and probably clonal. Gametocytes were found throughout this period. Our data suggest that this represented a focal outbreak, resulting in the infection of at least 40% of the villagers with a clonal parasite line. Thus, P. falciparum infections can persist for at least 1 year in a substantial proportion (10%) of the hosts. Implications for malaria control and the interpretation of epidemiological data are discussed.
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Background: Although CD4 cell count monitoring is used to decide when to start antiretroviral therapy in patients with HIV-1 infection, there are no evidence-based recommendations regarding its optimal frequency. It is common practice to monitor every 3 to 6 months, often coupled with viral load monitoring. We developed rules to guide frequency of CD4 cell count monitoring in HIV infection before starting antiretroviral therapy, which we validated retrospectively in patients from the Swiss HIV Cohort Study.Methodology/Principal Findings: We built up two prediction rules ("Snap-shot rule" for a single sample and "Track-shot rule" for multiple determinations) based on a systematic review of published longitudinal analyses of CD4 cell count trajectories. We applied the rules in 2608 untreated patients to classify their 18 061 CD4 counts as either justifiable or superfluous, according to their prior >= 5% or < 5% chance of meeting predetermined thresholds for starting treatment. The percentage of measurements that both rules falsely deemed superfluous never exceeded 5%. Superfluous CD4 determinations represented 4%, 11%, and 39% of all actual determinations for treatment thresholds of 500, 350, and 200x10(6)/L, respectively. The Track-shot rule was only marginally superior to the Snap-shot rule. Both rules lose usefulness for CD4 counts coming near to treatment threshold.Conclusions/Significance: Frequent CD4 count monitoring of patients with CD4 counts well above the threshold for initiating therapy is unlikely to identify patients who require therapy. It appears sufficient to measure CD4 cell count 1 year after a count > 650 for a threshold of 200, > 900 for 350, or > 1150 for 500x10(6)/L, respectively. When CD4 counts fall below these limits, increased monitoring frequency becomes advisable. These rules offer guidance for efficient CD4 monitoring, particularly in resource-limited settings.
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OBJECTIVES: To determine clinical and ultrasonographic predictors of joint replacement surgery across Europe in primary osteoarthritis (OA) of the knee. METHODS: This was a 3-year prospective study of a painful OA knee cohort (from a EULAR-sponsored, multicentre study). All subjects had clinical evaluation, radiographs and ultrasonography (US) at study entry. The rate of knee replacement surgery over the 3-year follow-up period was determined using Kaplan-Meier survival data analyses. Predictive factors for joint replacement were identified by univariate log-rank test then multivariate analysis using a Cox proportional-hazards regression model. Potential baseline predictors included demographic, clinical, radiographic and US features. RESULTS: Of the 600 original patients, 531 (88.5%), mean age 67+/-10 years, mean disease duration 6.1+/-6.9 years, had follow-up data and were analysed. During follow-up (median 3 years; range 0-4 years), knee replacement was done or required for 94 patients (estimated event rate of 17.7%). In the multivariate analysis, predictors of joint replacement were as follows: Kellgren and Lawrence radiographic grade (grade > or =III vs <III, hazards ratio (HR) = 4.08 (95% CI 2.34 to 7.12), p<0.0001); ultrasonographic knee effusion (> or =4 mm vs <4 mm) (HR = 2.63 (95% CI 1.70 to 4.06), p<0.0001); knee pain intensity on a 0-100 mm visual analogue scale (> or =60 vs <60) (HR = 1.81 (95% CI 1.15 to 2.83), p=0.01) and disease duration (> or =5 years vs <5 years) (HR=1.63 (95% CI 1.08 to 2.47), p=0.02). Clinically detected effusion and US synovitis were not associated with joint replacement in the univariate analysis. CONCLUSION: Longitudinal evaluation of this OA cohort demonstrated significant progression to joint replacement. In addition to severity of radiographic damage and pain, US-detected effusion was a predictor of subsequent joint replacement.
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PURPOSE There has been little research describing the involvement of family physicians in the follow up of patients with cancer especially during the primary treatment phase We undertook a prospective longitudinal study of patients with lung cancer to assess their family physician s involvement in their follow up at the different phases of cancer METHODS In 5 hospitals in the province of Quebec Canada patients with a recent diagnosis of lung cancer were surveyed every 3 to 6 months whether they had metastasis or not, for a maximum of 18 months to assess aspects of their family physician s involvement in cancer care RESULTS Of the 395 participating patients 92% had a regular family physician but only 60% had been referred to a specialist by him/her or a colleague for the diagnosis of their lung cancer A majority of patients identified the oncology team or oncologists as mainly responsible for their cancer care throughout their cancer journey except at the advanced phase where a majority attributed this role to their family physician At baseline only 16% of patients perceived a shared care pattern between their family physician and oncologists but this pro portion increased with cancer progression Most patients would have liked their family physician to be more involved in all aspects of cancer care CONCLUSIONS Although patients perceive that the oncology team is the main party responsible for the follow up of their lung cancer they also wish their family physicians to be involved Better communication and collaboration between family physicians and the oncology team are needed to facilitate shared care in cancer follow up
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The calculation of elasticity parameters by sonic and ultra sonic wave propagation in saturated soils using Biot's theory needs the following variables : forpiation density and porosity (p, ø), compressional and shear wave velocities (Vp, Vs), fluid density, viscosity and compressibility (Pfi Ilfi Ki), matrix density and compressibility (p" K), The first four parameters can be determined in situ using logging probes. Because fluid and matrix characteristics are not modified during core extraction, they can be obtained through laboratory measurements. All parameters necessitate precise calibrations in various environments and for specific range of values encountered in soils. The slim diameter of boreholes in shallow geophysics and the high cost of petroleum equipment demand the use of specific probes, which usually only give qualitative results. The measurement 'of density is done with a gamma-gamma probe and the measurement of hydrogen index, in relation to porosity, by a neutron probe. The first step of this work has been carried out in synthetic formations in the laboratory using homogeneous media of known density and porosity. To establish borehole corrections different casings have been used. Finally a comparison between laboratory and in situ data in cored holes of known geometry and casing has been performed.
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This article presents a longitudinal study of the development of "family alliance" from pregnancy to toddlerhood in a community sample, as well as its links with the emotional and cognitive development of the child at age 5 years. Family alliance is defined as the quality of the interactive coordination between family members. We consider that the alliance constitutes a context for the child to learn emotion regulation and to develop an understanding of inner states. Family interactions (N = 38) were observed at the 5th month of pregnancy and at 3, 9, and 18 months after birth in a standardized situation of observation (Lausanne Trilogue Play). Marital satisfaction and child temperament were assessed through self-reported questionnaires. Several outcomes of the child at age 5 years were measured: theory of mind performances, predominant emotional themes in pretend play, internalized and externalized symptoms. Results show that (a) three patterns of evolution of family alliance occur: "high stable" (n = 19), "high to low" (n = 10), and "low stable" (n = 9); (b) a high stable alliance is predictive of better outcomes in children at age 5 years, especially regarding theory of mind; (c) the temperament of the child is predictive of child outcomes; and (d) an interaction effect occurs between family alliance and temperament. These results highlight the importance of both family-level and individual-level variables for understanding individual differences in the social and cognitive development of children.
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AIMS: Although the coronary artery vessel wall can be imaged non-invasively using magnetic resonance imaging (MRI), the in vivo reproducibility of wall thickness measures has not been previously investigated. Using a refined magnetization preparation scheme, we sought to assess the reproducibility of three-dimensional (3D) free-breathing black-blood coronary MRI in vivo. METHODS AND RESULTS: MRI vessel wall scans parallel to the right coronary artery (RCA) were obtained in 18 healthy individuals (age range 25-43, six women), with no known history of coronary artery disease, using a 3D dual-inversion navigator-gated black-blood spiral imaging sequence. Vessel wall scans were repeated 1 month later in eight subjects. The visible vessel wall segment and the wall thickness were quantitatively assessed using a semi-automatic tool and the intra-observer, inter-observer, and inter-scan reproducibilities were determined. The average imaged length of the RCA vessel wall was 44.5+/-7 mm. The average wall thickness was 1.6+/-0.2 mm. There was a highly significant intra-observer (r=0.97), inter-observer (r=0.94), and inter-scan (r=0.90) correlation for wall thickness (all P<0.001). There was also a significant agreement for intra-observer, inter-observer, and inter-scan measurements on Bland-Altman analysis. The intra-class correlation coefficients for intra-observer (r=0.97), inter-observer (r=0.92), and inter-scan (r=0.86) analyses were also excellent. CONCLUSION: The use of black-blood free-breathing 3D MRI in conjunction with semi-automated analysis software allows for reproducible measurements of right coronary arterial vessel-wall thickness. This technique may be well-suited for non-invasive longitudinal studies of coronary atherosclerosis.
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Today's approach to anti-doping is mostly centered on the judicial process, despite pursuing a further goal in the detection, reduction, solving and/or prevention of doping. Similarly to decision-making in the area of law enforcement feeding on Forensic Intelligence, anti-doping might significantly benefit from a more extensive gathering of knowledge. Forensic Intelligence might bring a broader logical dimension to the interpretation of data on doping activities for a more future-oriented and comprehensive approach instead of the traditional case-based and reactive process. Information coming from a variety of sources related to doping, whether directly or potentially, would feed an organized memory to provide real time intelligence on the size, seriousness and evolution of the phenomenon. Due to the complexity of doping, integrating analytical chemical results and longitudinal monitoring of biomarkers with physiological, epidemiological, sociological or circumstantial information might provide a logical framework enabling fit for purpose decision-making. Therefore, Anti-Doping Intelligence might prove efficient at providing a more proactive response to any potential or emerging doping phenomenon or to address existing problems with innovative actions or/and policies. This approach might prove useful to detect, neutralize, disrupt and/or prevent organized doping or the trafficking of doping agents, as well as helping to refine the targeting of athletes or teams. In addition, such an intelligence-led methodology would serve to address doping offenses in the absence of adverse analytical chemical evidence.
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OBJECTIVE: To determine in chimpanzees if candidate HIV-1 subunit protein vaccines were capable of eliciting long-lasting T-cell memory responses in the absence of viral infection, and to determine the specific characteristics of these responses. DESIGN: A longitudinal study of cell-mediated immune responses induced in three chimpanzees following immunization with subunit envelope glycoproteins of either HIV-1 or herpes simplex virus (HSV)-2. Following these pre-clinical observations, four human volunteers who had been immunized 7 years previously with the same HIV-1 vaccine candidate donated blood for assessment of immune responses. METHODS: Responses were monitored by protein and peptide based ELISpot assays, lymphocyte proliferation, and intracellular cytokine staining. Humoral responses were assessed by enzyme-linked immunosorbent assay and virus neutralization assays. RESULTS: Although antigen (Ag)-specific CD4 T-cell responses persisted for at least 5 years in chimpanzees, CD8 T-cell responses were discordant and declined within 2 years. Detailed cellular analyses revealed that strong Th1 in addition to Th2 type responses were induced by AS2/gp120 and persisted, whereas CD8 T-cell memory declined in peripheral blood. The specificity of both Th and cytotoxic T-lymphocyte responses revealed that the majority of responses were directed to conserved epitopes. The remarkable persistence of Ag-specific CD4 T-cell memory was characterized as a population of the CD45RA-CD62L-CCR7- "effector phenotype" producing the cytokines IFNgamma, IL-2 and IL-4 upon epitope-specific recognition. Importantly, results in chimpanzees were confirmed in peripheral blood of one of four human volunteers studied more than 7 years after immunization. CONCLUSION: These studies demonstrate that epitope-specific Th1 and Th2 cytokine-dependent Th responses can be induced and maintained for longer than 5 years by immunization with subunit proteins of HIV-1.
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Summary The present thesis work focused on the ecology of benthic invertebrates in the proglacial floodplain of the Rhone in the Swiss Alps. The main glacial Rhone River and a smaller glacial tributary, the Mutt River, joined and entered a braiding multi-thread area. A first part concentrated on the disruption of the longitudinal patterns of environmental conditions and benthic invertebrate fauna in the Rhone by its tributary the Mutt. The Mutt had less harsh environmental conditions, higher taxonomic richness and more abundant zoobenthos compared to the Rhone upstream of the confluence. Although the habitat conditions in the main stream were little modified by the tributary, the fauna was richer and more diverse below the confluence. Colonisation from the Mutt induced the occurrence of faunal elements uncommon of glacial streams in the upper Rhone, where water temperature remains below 4°C. Although the glacial Rhone dominated the system with regard to hydrology and certain environmental conditions, the Mutt tributary has to be seen as the faunal driver of the system. The second part of the study concerned the spatio-temporal differentiation of the habitats and the benthic communities along and across the flood plain. No longitudinal differentiation was found. The spatial transversal differentiation of three habitat types with different environmental characteristics was successfully reflected in the spatial variability of benthic assemblages. This typology separated marginal sites of the flood plain, left bank sites under the influence of the Mutt, and the right bank sites under the influence of the Rh6ne. Faunistic spatial differences were emphasized by the quantitative structure of the fauna, richness, abundances and Simpson index of diversity. Seasonal environmental variability was positively related with Simpson index of diversity and the total richness per site. Low flow conditions were the most favourable season for the fauna and November was characterized by low spatial environmental heterogeneity, high spatial heterogeneity of faunal assemblage, maximum taxonomic richness, a particular taxonomic composition, highest abundances, as well as the highest primary food resources. The third part studied the egg development of three species of Ephemeroptera in the laboratory at 1.5 to 7°C and the ecological implications in the field. Species revealed very contrasting development strategies. Baetis alpinus has a synchronous and efficient egg development, which is faster in warmer habitats, enabling it to exploit short periods of favourable conditions in the floodplain. Ecdyonurus picteti has a very long development time slightly decreasing in warmer conditions. The high degree of individual variation suggests a genetic determination of the degree-days demand. Combined with the glacial local conditions, this strategy leads to an extreme delay of hatching and allows it to develop in very unpredictable habitats. Rhithrogena nivata is the second cold adapted species in Ephemeroptera. The incubation duration is long and success largely depends on the timing of hatching and the discharge conditions. This species is able to exploit extremely unstable and cold habitats where other species are limited by low water temperatures. The fourth part dealt with larval development in different habitats of the floodplain. Addition of data on egg development allowed the description of the life histories of the species from oviposition until emergence. Rhithrogena nivata and loyolaea generally have a two-year development, with the first winter passed as eggs and the second one as larvae. Development of Ecdyonurus picteti is difficult to document but appears to be efficient in a harsh and unpredictable environment. Baetis alpinus was studied separately in four habitats of the floodplain system with contrasting thermal regimes. Differences in success and duration of larval development and in growth rates are emphasised. Subvention mechanisms between habitats by migration of young or grown larvae were demonstrated. Development success and persistence of the populations in the system were thus increased. Emergence was synchronised to the detriment of the optimisation of the adult's size and fecundity. These very different development strategies induce a spatial and temporal distribution in the use of food resources and ecological niches. The last part of this work aimed at the synthesis of the characteristics and the ecological features of three distinct compartments of the system that are the upper Rhone, the Mutt and the floodplain. Their particular role as well as their inter-dependence concerning the structure and the dynamics of the benthic communities was emphasised. Résumé Ce travail de thèse est consacré à l'écologie des invertébrés benthiques dans la zone alluviale proglaciaire du Rhône dans les Alpes suisses. Le Rhône, torrent glaciaire principal, reçoit les eaux de la Mutt, affluent glaciaire secondaire, puis pénètre dans une zone de tressage formée de plusieurs bras. La première partie de l'étude se concentre sur la disruption par la Mutt des processus longitudinaux, tant environnementaux que faunistiques, existants dans le Rhône. Les conditions environnementales régnant dans la Mutt sont moins rudes, la richesse taxonomique plus élevée et le zoobenthos plus abondant que dans le Rhône en amont de la confluence. Bien que les conditions environnementales dans le torrent principal soient peu modifiées par l'affluent, la faune s'avère être plus riche et plus diversifiée en aval de la confluence. La colonisation depuis la Mutt permet l'occurrence de taxons inhabituels dans le Rhône en amont de la confluence, où la température de l'eau se maintient en dessous de 4°C. Bien que le Rhône, torrent glaciaire principal, domine le système du point de vu de l'hydrologie et de certains paramètres environnementaux, l'affluent Mutt doit être considéré comme l'élément structurant la faune dans le système. La deuxième partie concerne la différentiation spatiale et temporelle des habitats et des communautés benthiques à travers la plaine alluviale. Aucune différentiation longitudinale n'a été mise en évidence. La différentiation transversale de trois types d'habitats sur la base des caractéristiques environnementales a été confirmée par la variabilité spatiale de la faune. Cette typologie sépare les sites marginaux de la plaine alluviale, ceux sous l'influence de la Mutt (en rive gauche) et ceux sous l'influence du Rhône amont (en rive droite). Les différences spatiales de la faune sont mises en évidence par la structure quantitative de la faune, la richesse, les abondances et l'indice de diversité de Simpson. La variabilité saisonnière du milieu est positivement liée avec l'indice de diversité de Simpson et la richesse totale par site. L'étiage correspond à la période la plus favorable pour la faune et novembre réunit des conditions de faible hétérogénéité spatiale du milieu, de forte hétérogénéité spatiale de la faune, une richesse taxonomique maximale, une composition faunistique particulière, les abondances ainsi que les ressources primaires les plus élevées. La troisième partie est consacrée à l'étude du développement des oeufs de trois espèces d'Ephémères au laboratoire à des températures de 1.5 à 7°C, ainsi qu'aux implications écologiques sur le terrain. Ces espèces présentent des stratégies de développement très contrastées. Baetis alpinus a un développement synchrone et efficace, plus rapide en milieu plus chaud et lui permettant d'exploiter les courtes périodes de conditions favorables. Ecdyonurus picteti présente une durée de développement très longue, diminuant légèrement dans des conditions plus chaudes. L'importante variation interindividuelle suggère un déterminisme génétique de la durée de développement. Cette stratégie, associée aux conditions locales, conduit à un décalage extrême des éclosions et permet à l'espèce de se développer dans des habitats imprévisibles. Rhithrogena nivata est la seconde espèce d'Ephémères présentant une adaptation au froid. L'incubation des oeufs est longue et son succès dépend de la période des éclosions et des conditions hydrologiques. Cette espèce est capable d'exploiter des habitats extrêmement instables et froids, où la température est facteur limitant pour d'autres espèces. La quatrième partie traite du développement larvaire dans différents habitats de la plaine alluviale. Le développement complet est décrit pour les espèces étudiées de la ponte jusqu'à l'émergence. Rhithrogena nivata et loyolaea atteignent généralement le stade adulte en deux ans, le premier hiver étant passé sous forme d'oeuf et le second sous forme de larve. Le développement de Ecdyonurus picteti est difficile à documenter, mais s'avère cependant efficace dans un environnement rude et imprévisible. Baetis alpinus a été étudié séparément dans quatre habitats de la plaine ayant des régimes thermiques contrastés. La réussite et la durée du développement embryonnaire ainsi que les taux de croissance y sont variables. Des mécanismes de subvention entre habitats sont possibles par la migration de larves juvéniles ou plus développées, augmentant ainsi la réussite du développement et le maintien des populations dans le système. L'émergence devient synchrone, au détriment de l'optimisation de la taille et de la fécondité des adultes. Ces stratégies très différentes induisent une distribution spatiale et temporelle dans l'usage des ressources et des niches écologiques. La dernière partie synthétise les caractéristiques écologiques des trois compartiments du système que sont le Rhône amont, la Mutt et la zone alluviale. Leurs rôles particuliers et leurs interdépendances du point de vue de la structure et de la dynamique des communautés benthiques sont mis en avant.
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The athlete biological passport (ABP) was recently implemented in anti-doping work and is based on the individual and longitudinal monitoring of haematological or urine markers. These may be influenced by illicit procedures performed by some athletes with the intent to improve exercise performance. Hence the ABP is a valuable tool in the fight against doping. Actually, the passport has been defined as an individual and longitudinal observation of markers. These markers need to belong to the biological cascade influenced by the application of forbidden hormones or more generally, affected by biological manipulations which can improve the performance of the athlete. So far, the haematological and steroid profile modules of the ABP have been implemented in major sport organisations, and a further module is under development. The individual and longitudinal monitoring of some blood and urine markers are of interest, because the intraindividual variability is lower than the corresponding interindividual variability. Among the key prerequisites for the implementation of the ABP is its prospect to resist to the legal and scientific challenges. The ABP should be implemented in the most transparent way and with the necessary independence between planning, interpretation and result management of the passport. To ensure this, the Athlete Passport Management Unit (APMU) was developed and the WADA implemented different technical documents associated to the passport. This was carried out to ensure the correct implementation of a profile which can also stand the challenge of any scientific or legal criticism. This goal can be reached only by following strictly important steps in the chain of production of the results and in the management of the interpretation of the passport. Various technical documents have been then associated to the guidelines which correspond to the requirements for passport operation. The ABP has been completed very recently by the steroid profile module. As for the haematological module, individual and longitudinal monitoring have been applied and the interpretation cascade is also managed by a specific APMU in a similar way as applied in the haematological module. Thus, after exclusion of any possible pathology, specific variation from the individual norms will be then considered as a potential misuse of hormones or other modulators to enhance performance.
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RESUME :Les fourmis du groupe Formica rufa, ou fourmis des bois, ainsi appelées en raison de leur préférence pour les écosystèmes forestiers, sont parmi les fourmis les plus fascinantes et les plus étudiées d'Europe. Ces fourmis jouent un rôle clé dans la plupart des forêts dans lesquelles elles vivent et sont considérées comme étant les meilleurs bioindicateurs de ces milieux. Pour ces raisons, les fourmis des bois sont protégées par la loi dans de nombreux pays européens, y compris en Suisse. Cependant, malgré leur protection, ces fourmis sont inscrites sur la liste rouge des espèces menacées dans plusieurs pays d'Europe et il est donc indispensable de bien les connaître afin de mieux les protéger.À l'heure actuelle, on considère que le groupe Formica rufa est composé de six espèces distinctes : F. rufa, F. polyctena, F. lugubris, F. paralugubris, F. aquilonia et F. pratensis. Toutefois, malgré la grande quantité d'études effectuées sur ces espèces, la systématique et l'identification des fourmis des bois sont toujours sujettes à discussion. Ceci est essentiellement dû au fait que ces espèces sont morphologiquement similaires et qu'elles sont parfois capables de s'hybrider ou de former des colonies mixtes.Une des conditions fondamentales pour toute étude en biologie de la conservation est l'identification correcte des espèces à protéger. Avec cette étude, nous désirons donc dénouer les problèmes liés à la systématique des fourmis des bois et analyser la diversité de ces espèces en adoptant une approche multidisciplinaire.Nous avons d'abord étudié la distribution des espèces jumelles F. lugubris et F. paralugubris dans les Álpes italiennes en re-analysant l'une des plus grandes collections de références sur ces espèces, déposée à l'Université de Pavie, Italie, et en récoltant de nouveaux échantillons sur le terrain. Nos analyses ont montré que F, paralugubris, décrite récemment et souvent «oubliée »par les chercheurs, est bien présente dans les Alpes et vit souvent en sympathie avec F. lugubris. Ensuite nous avons développé un outil moléculaire basé sur l'ADN mitochondrial pour une identification rapide et efficace de ces deux espèces. Au vu des bons résultats, nous avons étendu nos analyses génétiques (microsatellites) à toutes les espèces du groupe F. rufa, ce qui nous a permis de montrer que les outils moléculaires sont très efficaces pour identifier ces fourmis. En outre, nos analyses ont mis en évidence la présence d'une nouvelle espèce cryptique (appelée F. lugubris-X) au sein du Parc National Suisse. L'existence d'une nouvelle espèce peut avoir une grande influence sur les projets de conservation en faveur de ces espèces. Nous avons donc décidé de confirmer ce résultat avec des analyses comportementales et des analyses chimiques basées sur les phéromones sexuelles des différentes espèces, y compris F. lugubris-X. Les deux approches confirment nos données génétiques et indiquent que F. lugubris-X représente bel et bien une nouvelle espèce de fourmis des bois dans les Alpes Suisses.Les résultats de cette étude ont une grande importance du point de vue de la biodiversité. En plus, ils livrent aux futurs chercheurs des outils fiables pour l'identification des fourmis des bois et ouvrent de captivantes perspectives pour une meilleure protection de ces insectes et, par conséquent, de nos écosystèmes forestiers. .Abstract :Mound building red wood ants (species of the Formica rufa group) belong to one of the most studied groups of ants in Europe and have fundamental roles and positive effects in forested habitats of the northern hemisphere. In addition, they are considered among the most promising bioindicators of forest ecosystems. Because of their importance, these ants are protected by law in many European countries, including Switzerland. However, despite this protection, they are included on the red list of threatened species edited by the International Union for Conservation of Nature (IUCN) and on the red list of some particular countries like Switzerland. Because of their similar morphology and a high intraspecific variability, the morphological identification of these species can be quite complicated. In addition, they are sometimes able to hybridize or to form mixed colonies. Consequently, the taxonomy of this group of ants has been much debated during the past decades. Based on a phylogenetic study, today the group is considered to count six species in Europe: F. rufa, F. po/yctena, F. lugubris, F. paralugubris, F. aquilonia and F. pratensis. Nevertheless, the taxonomy of the group is often neglected mainly due to the lack of reliable and easy to use identification methods.Considering the importance of correct species assessment in conservation biology, in this study we want to disentangle the taxonomical difficulties within the Formica rufa group and to clarify the diversity of these protected ants, by using an integrative approach.We first analyzed the distribution of .the sibling species F. lugubris and F. paralugubris in the Italian Alps by collecting new samples on the field and by examining one of the major red wood ant collections, which is deposited at the University of Pavia, Italy. After that, we developed a molecular tool based on mitochondria) DNA, which provides a reliable and easy-to-use technique for the identification of F. lugubris and F. paralugubris. Afterwards, we extended the use of molecular markers for species identification to the whole F. rufa group and made a microsatellite analysis. Results confirm that molecular markers are consistent tools for species identification and that the six known species represent six different genetic pools. In addition, genetic data highlighted the existence of a new cryptic species in the Swiss Alps, called Formica lugubris-X.The presence of a new species can have a great influence on future conservation plans in favour of these protected ants and consequently for forested habitats. We therefore completed molecular data by behavioural (pupae recognition) and chemical analyses based on six pheromones of the entire F. rufa group. Both approaches are in accordance to genetic results and confirm that F. lugubris-X really represents a new cryptic species of red wood ant within the Swiss National Park (Eastern Swiss Alps).Results obtained in this study have a great importance in terms of biodiversity. Moreover, they provide important taxonomical information, reliable tools for species identifications and future perspectives for a consequent conservation of red wood ant species.