1,076 research outputs found

    Supporting the Oral Language Development of Young Dual Language Learners: Perspectives of EL Teachers in NH

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    Demographic shifts in the US over the last two decades have increased the diversity gap between teachers and their students. The majority of multilingual children entering US public schools face the challenge of learning academic content in not just one, but two languages. Despite many of the positive effects of being bilingual, Dual Language Learners (DLLs) often face more challenges in education achievement and opportunities than their monolingual English-speaking peers. A key factor of this challenge is the fact that DLLs tend to have monolingual English-speaking peers, and teachers have been shown to play a critical role in student learning. Through surveys, interviews, and classroom observations, this study explores to what extent NH teachers of DLLs understand and enact research-based practices known to develop oral language. Contextual factors such as level of administrative support and availability of resources in students’ first languages were also identified as affecting teachers’ practices. Research such as this aims to shed light on whether or how research-based practices are making their way into classroom practices. The implications will shed light on the needs for teacher and administrator preparation

    Selection of borehole temperature depth profiles for regional climate reconstructions

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    International audienceBorehole temperature depth profiles are commonly used to infer time variations in the ground surface temperature on centennial time scales. We compare different procedures to obtain a regional ground surface temperature history (GSTH) from an ensemble of borehole temperature depth profiles. We address in particular the question of selecting profiles that are not contaminated by non climatic surface perturbations and we compare the joint inversion of all the profiles with the average of individual inversions. We show that the resolution and the stability of the inversion of selected profiles are much improved over those for a complete data set. When profiles have been selected, the average GSTH of individual inversions and the GSTH of the joint inversion are almost identical. This is not observed when the entire data set is inverted: the average of individual inversions is different from the joint inversion. We also show that the joint inversion of very noisy data sets does not improve the resolution but, on the contrary, causes strong instabilities in the inversion. When the profiles that are affected by noise can not be eliminated, averaging of the individual inversions yields the most stable result, but with very poor resolution

    Early Huntington's disease affects movements in transformed sensorimotor mappings

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    This study examined the effect of transformed visual feedback on movement control in Huntington’s disease (HD). Patients in the early stages of HD and controls performed aiming movements towards peripheral targets on a digitizing tablet using an indirect visual control of movement through a monitor and emphasizing precision. In a baseline condition, HD patients were slower but showed few precision problems in aiming. When visual feedback was inverted in both vertical and horizontal axes, patients showed problems in initial and terminal phases of movement where feedback is most critical. When visual feedback was inverted along a single axis as in a mirror-inversion, HD patients showed large deviations and over-corrections before adaptation. Adaptation was similar in both groups. These results suggest that HD impairs on-line error correction in novel movements

    Information and Opportunistic Behavior in Federal Crop Insurance Programs

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    Opportunistic behavior in crop insurance can arise due to asymmetric information between producers and the Federal Crop Insurance Corporation. Producers who insure fields using transitional yields based on county average yields or who select options such as buy-up coverage or revenue insurance may increase their return from crop insurance. Using field-level crop insurance contract data for several crops in five growing regions, we find evidence that producers can profit from using buy-up coverage, revenue insurance, and transitional yields and that the level of producer opportunism is crop but not necessarily land-quality specific and is greater due to premium subsidization.opportunistic behavior, crop insurance, buy-up, revenue, transitional yields

    The Effects of Transitional Yields on Adverse Selection in Crop Insurance

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    Transitional yields based on county average can be used by producers as the basis to obtain crop insurance on fields that have not previously produced the crop. Using field-level crop insurance contract data for several crops in five different growing regions we examine the impact of this asymmetric information on adverse selection. Our results indicate that adverse selection does exist from the use of transitional yields and that it is crop specific but not land-quality specific.adverse selection, crop insurance, transitional yields, Risk and Uncertainty, Q18,

    Régie des populations de Cydia pomonella (Lepidoptera : Tortricidea) dans les vergers commerciaux du Québec avec des phéromones de synthèse

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    Des diffuseurs à phéromones sexuelles de synthèse ont été installés en 1992 et 1993 dans trois vergers de pommiers (Malus pumila) du Québec, à raison de 1000 diffuseurs ha lors d'un essai de régie des populations de carpocapse de la pomme, Cydia pomonella [Lepidoptera : Tortricidae]. De 1991 à 1992, soit après un an d'essai, les dégâts de carpocapse à la récolte sont passés de 54 % à 32 %, de 11 % à 2 %, et se sont maintenus à 0 % dans les vergers à forte, moyenne et faible pressions de carpocapse, respectivement. Après deux ans d'essai, les dégâts sont demeurés au même niveau ou ont été diminués davantage selon le type de programme de répression utilisé contre les autres ravageurs. En 1993, une baisse de 75-100 % des captures a aussi été observée dans les pièges à phéromones par rapport aux captures observées en 1991.Pheromone dispensers were installed in 1992 and 1993, at a rate of 1000 dispensers ha1, in three Quebec apple (Malus pumila) orchards, to reduce populations of the codling moth, Cydia pomonella [Lepidoptera : Tortricidae]. After one year, codling moth damage at harvest decreased from 54% to 32%, from 11% to 2% and remained at 0% in the high, medium and low codling moth pressure orchards, respectively. Damage remained at the same level after the second year, or further decreased, depending on the type of spray program used against other pests. Pheromone trap catches in 1993 also decreased from 75 to 100% when compared to 1991 catches

    Managing apple maggot, Rhagoletis pomonella [Diptera : Tephritidae], by perimeter trapping

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    Le piégeage des adultes de la mouche de la pomme (Rhagoletis pomonella) en périphérie des vergers de pommiers (Malus pumila) est une méthode de lutte physique efficace. En vergers commerciaux, il a permis d'obtenir de 99,5 à 100 % de fruits sains à la récolte. Les pièges consistaient en des sphères rouges (9 cm diam.) ou des panneaux jaunes (28 cm x 21,5 cm) insérés entre deux demi-sphères rouges. Ils étaient enduits de colle et appâtés d'hexanoate de butyle. Le nombre de pièges installés a été déterminé en fonction de la longueur de la façade directement exposée à un site d'infestation potentielle par le R. pomonella. Dans les parcelles, sur les côtés adjacents à un boisé, les pièges étaient placés à environ 10 m de distance sur le rang, ou sur les pommiers à l'extréminté de chacun des rangs. Sur les côtés adjacents à des prairies de graminées ou à des vergers traités chimiquement, on a placé les pièges à environ 20 m d'intervalle. Afin d’obtenir un niveau de contrôle acceptable par les pomiculteurs, les populations de la mouche de la pomme doivent être de faibles à modérées. La sensibilité aux attaques de la mouche de la pomme a varié d'un cultivar à l'autre. Ce facteur doit être considéré si Ton veut appliquer cette méthode en conditions commerciales.Perimeter trapping is an effective physical method to control apple maggot (Rhagoletis pomonella) in apple (Malus pumila) orchards. It provided 99.5 to 100 % clean fruit at harvest in commercial orchards. The traps were red spheres (9 cm diam) or yellow boards (28 cm x 21.5 cm) sandwiched between the two halves of red spheres. They were coated with a sticky material and baited with butyl hexanoate. The number of traps per plot was a function of the length of the plot facing a possible entry site of R. pomonella. In plots adjacent to forest, traps were placed at ca. 10 m intervals on the row, or on the outer most tree of every row. Sides of plots adjacent to prairie grass or a chemically-treated plot had traps at approximately 20-m intervals. To achieve commercially acceptable apple maggot control, the activity of the pest should be low to moderate. Susceptiblity to apple maggot attack varied from one apple cultivar to another. Therefore, this criterion should be considered when perimeter trapping of apple maggot is envisaged

    Ecology and management of plum curculio, Conotrachelus nenuphar [Coleoptera :Curculionidae], in apple orchards

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    Le charançon de la prune (Conotrachelus nénuphar) est un insecte originaire de l'Amérique du Nord. Il s'attaque aux fruits à pépins et à noyaux de l'est des États-Unis et du Canada. Il est un ravageur prépondérant en vergers de pommiers (Maluspumila) au Québec. Au printemps, les adultes se déplacent de leurs sites d'hibernation, localisés principalement dans les boisés, vers les vergers. Avant la nouaison, l'activité de ces insectes est surtout nocturne, mais elle s'étend à toute la journée dès l'apparition des fruits. Les larves quittent le fruit au moment de la chute physiologique, et la pupaison s'effectue dans le sol. La nouvelle génération d'adultes apparaît en août, et se nourrit de fruits jusqu'à l'automne, puis retourne vers les sites d’hibernation. Plusieurs éléments de la bio-écologie du charançon sont méconnus, notamment les relations entre l’insecte et l’hôte, le comportement, la dispersion, le mode de déplacement, la reconnaissance des plantes hôtes et des sites d’hibernation, l’orientation, et les seuils économiques. Il n’existe actuellement aucune méthode fiable pour dépister ce charançon, et aucun moyen biologique de lutte contre ce ravageur. Cependant, des études récentes sur le comportement et l’activité du charançon de la prune en conditions semi-naturelles et naturelles pourraient permettre le développement de stratégies de lutte plus efficaces. Ces travaux sont présentés ici de même qu’une revue des méthodes de lutte (chimique, biologique, génétique, mécanique et culturale) envisageables contre le charançon de la prune.Plum curculio (Conotrachelus nenuphar) is a native pest of pome and stone fruit in eastern North America. It is a key pest of apple (Malus pumila) orchards in Quebec. In spring, adults disperse primarily from woodland overwintering sites to apple orchards. Before fruit set, the beetles are mainly nocturnal. As fruits become available for oviposition, adults extend their activity to the daytime. Full grown larvae found in dropped apples in June (June drop) enter the soil to pupate. The summer brood emerges in August, feeds on the remaining fruit throughout the fall and then disperses to suitable overwintering sites. Little is known of its community and host plant relationships, dispersal behavior, factors influencing its mode of locomotion, choice of food sources, overwintering sites, micro-habitat selection, orientation, and action threshold. Commercially available biocontrol agents are not effective, and convenient and reliable monitoring techniques for the timing of sprays have not been developed. However, recent field and insectary studies on the behavior and activity of plum curculio adults may allow us to improve the efficiency of control strategies. These findings are presented here, together with their implications for control of the plum curculio by modifying its habitat, and by better timing and location of sprays and other interventions. This paper also includes brief reviews of biological controls, insect growth regulators, and genetic controls for plum curculio
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