214 research outputs found

    Etude à l'échelle de la plante entière du fonctionnement hydrique et photosynthétique de la vigne: comparaison des systèmes de conduite traditionnel et en Lyre

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    Le fonctionnement hydrique et photosynthétique à l'échelle des ceps entiers a été suivi simultanément en milieu naturel sur des vignes étroites traditionnelles et conduites en Lyre. Cette étude a été réalisée sur Cabernet Sauvignon/101-14, planté en sol de graves. Les observations relatives au comportement hydrique (potentiel hydrique et foliaire, transpiration, par unite de surface foliaire) des deux systèmes de conduite utilisés indiquent que la vigne traditionnelle se trouve dans un meilleur état hydrique comparativement à la vigne conduite en Lyre. Cette différence est en rapport avec les valeurs de l'assimilation nette par unité de surface foliaire, nettement supérieures sur la vigne traditionnelle. Il semble toutefois que l'existence d'une surface foliaire par surface de sol plus importante chez la vigne conduite en Lyre compense le taux réduit de photosynthèse par unité de surface folaire. Cette compensation conduit à une production agronomique voisine chez les deux systèmes de conduite.La conclusion principale de cette étude est qu'une contrainte hydrique ayant un effet dépressif sur l'assimilation nette peut avoir, en revanche, des conséqences favorables sur l'élaboration des critères qualitatifs, notamment la synthèse des polyphénols.Photosynthesis and transpiration studies with traditionally and lyre-trained vinesWater and photosynthetic functions on a plant scale were studied simultaneously on traditionally and lyre-shaped grapevines grown in field conditions. The study was carried out on Cabernet Sauvignon/101-14 planted in gravelly soil. Observations concerning the water behavior (leaf water potential, transpiration per leaf surface unit) of both training systems used indicate that the traditional vine manifests a better water status when compared with the lyre-shaped vine. The difference is in agreement with net photosynthesis values per leaf surface unit, clearly superior on the traditional vine. It seems, however, that the existence of a greater leaf surface per soil surface in the lyre-shaped vine compensates the reduction in photosynthesis per leaf surface. The compensation results in very close agronomical yield for both training systems. The main conclusion of this study is that a water constraint having a diminishing effect on net photosynthesis can, on the other hand, have favorable consequences on the elaboration of qualitative criteria, in particular, the synthesis of polyphenols

    Automated grain size measurements from airborne remote sensing for long profile measurements of fluvial grain sizes

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    Recent research has demonstrated that image processing can be applied to derive surficial median grain size data automatically from high-resolution airborne digital imagery in fluvial environments. However, at the present time, automated grain size measurement is limited to the dry exposed bed areas of the channel. This paper shows that the application area of automated grain size mapping can be extended in order to include the shallow wetted areas of the channel. The paper then proceeds to illustrate how automated grain size measurement in both dry and shallow wetted areas can be used to measure grain sizes automatically for long river lengths. For the present study, this results in a median grain size profile covering an 80 km long river which is constructed from over three million automated grain size measurements

    Back pressure effects on variable geometry turbine performances

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    Paper presented at the 6th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 30 June - 2 July, 2008.Turbochargers are widely used in applications to increase specific power and decrease fuel consumption. However, recent anti-pollution regulations have became stricter and pressed automotive engineers to find new solutions to reduce Nox emissions. Two of these solutions are the catalytic converter and the intercooler system. All these modifications will change the initial matching of the turbocharger performance characteristics to the engine requirements. In this paper, several compressor wheel sizes are investigated to evaluate the turbine/compressor matching. The intercooler and catalytic converter back pressure induced are respectively modeled by a lower duct section downstream the compressor stage and a variable valve downstream the turbine stage. The influences of the different modifications are identified through the loading and the flow coefficients and also on classical turbine performance maps. First, an analogy between compressor wheel size and back pressure effects is underlined. Second, it is shown that initial control settings of turbine nozzle vanes are no longer appropriate with a catalytic converter.vk201

    On Passion and Sports Fans:A Look at Football

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    The purpose of the present research was to test the applicability of the Dualistic Model of Passion (Vallerand et al., 2003) to being a sport (football) fan. The model posits that passion is a strong inclination toward an activity that individuals like (or even love), that they value, and in which they invest time and energy. Furthermore, two types of passion are proposed: harmonious and obsessive passion. While obsessive passion entails an uncontrollable urge to engage in the passionate activity, harmonious passion entails a sense of volition while engaging in the activity. Finally, the model posits that harmonious passion leads to more adaptive outcomes than obsessive passion. Three studies provided support for this dualistic conceptualization of passion. Study 1 showed that harmonious passion was positively associated with adaptive behaviours (e.g., celebrate the team’s victory), while obsessive passion was rather positively associated with maladaptive behaviours (e.g., to risk losing one’s employment to go to the team’s game). Study 2 used a short Passion Scale and showed that harmonious passion was positively related to the positive affective life of fans during the 2006 FIFA World Cup, psychological health (self-esteem and life satisfaction), and public displays of adaptive behaviours (e.g., celebrating one’s team victory in the streets), while obsessive passion was predictive of maladaptive affective life (e.g., hating opposing team’s fans) and behaviours (e.g., mocking the opposing team’s fans). Finally, Study 3 examined the role of obsessive passion as a predictor of partner’s conflict that in turn undermined partner’s relationship satisfaction. Overall, the present results provided support for the Dualistic Model of Passion. The conceptual and applied implications of the findings are discussed

    On passion and moral behavior in achievement settings: The mediating role of pride

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    The Dualistic Model of Passion (Vallerand et al., 2003) distinguishes two types of passion: harmonious passion (HP) and obsessive passion (OP) that predict adaptive and less adaptive outcomes, respectively. In the present research, we were interested in understanding the role of passion in the adoption of moral behavior in achievement settings. It was predicted that the two facets of pride (authentic and hubristic; Tracy & Robins, 2007) would mediate the passion-moral behavior relationship. Specifically, because people who are passionate about a given activity are highly involved in it, it was postulated that they should typically do well and thus experience high levels of pride when engaged in the activity. However, it was also hypothesized that while both types of passion should be conducive to authentic pride, only OP should lead to hubristic pride. Finally, in line with past research on pride (Carver, Sinclair, & Johnson, 2010; Tracy et al., 2009), only hubristic pride was expected to negatively predict moral behavior, while authentic pride was expected to positively predict moral behavior. Results of two studies conducted with paintball players (N=163, Study 1) and athletes (N=296, Study 2) supported the proposed model. Future research directions are discussed in light of the Dualistic Model of Passion

    The intergenerational association between parents' problem gambling and impulsivity-hyperactivity/inattention behaviors in children

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    Despite the well-established association between problem gambling and ADHD core categories of impulsivity-hyperactivity and inattention, the link between parents’ problem gambling and impulsivity-hyperactivity/inattention (IH/I) behaviors in children has not been investigated. This study investigated the association between parents’ problem gambling and children’s IH/I behaviors while controlling for potential confounding variables. A population-based prospective cohort followed-up from kindergarten to age 30, the Quebec Longitudinal Study of Kindergarten Children (QLSKC), provided data over three generations. Among 1358 participants at age 30, parents with a child aged 1 year or older (N=468; Mean age=4.65 years; SD=2.70) were selected. Generalized Linear Models included measures of grandparents’ and parents’ problem gambling, parents’ IH/I behaviors in childhood, and a host of risk factors and comorbidities to predict IH/I in children. Intergenerational bivariate associations were observed between grandparents’ problem gambling, parents’ IH/I in childhood and problem gambling at age 30, and between parents’ IH/I, problem gambling, and children’s IH/I behaviors. Parents’ problem gambling predicted children’s IH/I behaviors above and beyond the effects of covariates such as family and socioeconomic characteristics, alcohol and drug use, depression symptoms and parents’ gambling involvement. Parents’ IH/I behaviors in childhood also predicted children’s IH/I and had a moderating, enhancing effect on parents’ problem gambling association with their offspring’s IH/I behaviors. Problem gambling is a characteristic of parents’ mental health that is distinctively associated with children’s IH/I behaviors, above and beyond parents’ own history of IH/I and of typically related addictive, psychopathological or socioeconomic risk factors and comorbidities

    "I am becoming more and more like my eldest brother!": the relationship between older siblings, adolescent gambling severity, and the attenuating role of parents in a large-scale nationally representative survey study

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    The present study examined the association between having older siblings who gamble and adolescent at-risk/problem gambling and how parents (i.e., parental knowledge of their whereabouts) and peers might moderate such effects. Data were drawn from the ESPAD®Italia2012 survey (European School Survey Project on Alcohol and Other Drugs) comprising a nationally representative Italian sample of adolescents. The analysis was carried out on a subsample of 10,063 Italian students aged 15–19 years (average age = 17.10; 55 % girls) who had at least one older sibling and who had gambled at some point in their lives. Respondents’ problem gambling severity, older gambler sibling, gambler peers, parental knowledge, and socio-demographic characteristics were individually assessed. Multinomial logistic regression analyses including two- and three-way interactions were conducted. The odds of being an at-risk/problem gambler were higher among high school students with older siblings that gambled and those with peers who gambled. Higher parental knowledge (of who the adolescent was with and where they were in their leisure time) was associated with lower rates of at-risk/problem gambling. There was also an interaction between gamblers with older siblings and parental knowledge. The combination of having siblings who gambled and a greater level of parental knowledge was associated with lower levels of problem gambling. The present study confirmed the occurrence of social risk processes (older siblings and peers who gambled) and demonstrated that gambling among older siblings and peers represents an important contextual factor for increased at-risk/problem gambling. However, parental knowledge appears to be sufficient to counterbalance the influence of older siblings
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