Mobilisant un sondage avec un devis expérimental, cet article cherche à comprendre l'effet que peuvent avoir les heuristiques numériques d'acceptabilité sociale sur la capacité de convaincre. L'expérience expose les répondants à un article de nouvelle sur les réfugiés syriens et irakiens et, selon le traitement, à un fil de discussion comprenant différentes heuristiques numériques d'acceptabilité sociale. L’étude démontre que la présence d'un fil de discussion modifie l'effet à court terme que peut avoir l'article d'actualité initial et démontre également et surtout la façon dont les heuristiques numériques d'acceptabilité sociale ont un effet d'amplification sur la capacité de convaincre et les émotions évoquées par les commentaires. Chaque unité d'heuristique ou chaque recommandation n'augmente pas nécessairement d'autant le pouvoir de convaincre des commentaires associés et, pour les commentaires que les individus ne sont pas prédisposés à appuyer, servent plutôt à consolider les attitudes préexistantes et à polariser.

Education—and particularly public education—has become a crucible for the relationship between state and religious diversity, a principal site for contemporary debates about the meaning of secularism and the management of religious difference. This is so across a variety of national traditions, and despite wide differences in the historical and “emotional inheritances” surrounding the configuration of law, politics, and religion. Through an exploration of Hannah Arendt’s thought about responsibility and freedom in education, this article works towards a better understanding of why education is such a crucial and fraught field in the modern encounter between religion and law. The article turns to the recent jurisprudence of the Supreme Court of Canada to draw out the implications of these ideas, arriving ultimately at a claim about the nature and limits of the concept of state neutrality.

Investigations were conducted to establish the magnitude and pattern of differential expression of proteins due to generational selection of third instar Anopheles gambiae s.s. Giles larvae by cadmium, copper and lead heavy metals, the three possible common urban pollutants.

A susceptible strain of A. gambiae s.s. third instar larvae was separately placed under selection pressure with cadmium, copper and lead at LC30 and controls through five generations. First, third and fifth generation selection survivors were screened for differentially expressed proteins relative to non-exposed control by two-dimensional gel electrophoresis. Distribution patterns of the spots were analyzed by χ2 or Fishers' exact test and variations in expressions between and within generations by ANOVA. Most differentially expressed spots were acidic and of low molecular weight among all metals and generations. Type of heavy metal and generation were the main indicators of variations in differential expressions. Variation between generations was most significant among cadmium-selected populations of which the most number of spots were induced in the fifth generation. Most spots were induced in the copper-selected population in the third generation. The induced protein spots may be the products from respective genes that respond to heavy metals and counter their toxicity, thus building A. gambiae s.s. tolerance to these pollutants. The differential pattern and magnitude of expressed spots have potential application as molecular markers for assessment of anopheline adaptation status to heavy metals, and provide insight into the extent of environmental pollution.

Pour caractériser l'état d'un écosystème aquatique contaminé par des toxiques il est nécessaire de développer des méthodesd'évaluation des impacts écotoxicologiques, basées à la fois sur l'étude de réponses physiologiques et sur la structure des communautésvivant dans cet écosystème. La méthode PICT (Pollution-Induced Community Tolerance) proposée par Blanck et al.(1988), répond à ces deux critères. Elle est fondée sur l'hypothèse qu'une communauté biologique naturelle est constituée dedifférents «composants» ayant des sensibilités variables vis-à-vis d'un toxique donné. Ainsi, suite à une exposition à un toxique,les organismes les plus sensibles ne sont plus concurrentiels et sont remplacés par des organismes plus tolérants. La communautérésultante présente alors une tolérance vis-à-vis du toxique, supérieure à celle observée pour une communauté semblablemais n'ayant pas connu de pression de sélection par ce toxique. Cette différence de réponse peut donner une indication sur l'étatde pollution des milieux dans lesquels ont été échantillonnées différentes communautés. Le choix du test physiologique pourévaluer la tolérance de la communauté est fondamental car la réponse dépend d'une part, du mode d'action du toxique et d'autrepart, des mécanismes à l'origine de la tolérance de la communauté. Il existe peu d'outils de bioévaluation des milieux naturelssoumis à des contaminations toxiques, et cette méthode mérite donc d'être développée. Des travaux appliquant la méthode PICTà des communautés variées et dans divers milieux, permettraient de valider la méthode et de résoudre certains problèmes, quantà la détection de la tolérance. Le développement de méthodologies nouvelles pour caractériser la structure et la tolérance descommunautés étudiées est fondamental pour progresser dans nos connaissances sur le risque écotoxicologique.

Cowpea, Vigna unguiculata (L.) Walp., is susceptible to a wide spectrum of insect pests from seedling to harvest as well as in storage. Insecticide use has been the most commonly adopted method for the control of cowpea pests. However, due to the deleterious effects of insecticides on man, livestock and the environment, research over the years has been focused mainly on developing resistant/tolerant cultivars as a vital component in the integrated management of cowpea pests. This approach has, however, recorded varying degrees of success, due in part to the multiple and often overlapping pest complex attacking at different phenological growth stages of the crop.

In spite of the progress in the utilisation of insect-resistant cowpea varieties, the use of resistance as a control tactic has by no means been fully realised. There are many important cowpea insect pests for which resistant varieties are not yet available for commercial cultivation. Where resistant varieties are available for a given insect, these varieties may not be widely planted because of their unsuitability to local conditions.

In this paper, the status of host plant resistance research in cowpea is reviewed and some novel approaches aimed at solving its seemingly intractable pest problem are proposed, based on the state-of-the-art scientific and crop biotechnological development. The proposed framework for orientation of cowpea resistance research should ensure yield stability and sustainability for the resource-poor, smallscale farmers in Africa.

Sixty artificially infested grain sorghum genotypes were evaluated for resistance against Busseola fusca. Evaluation of leaf feeding damage indicated levels of resistance ranging from intermediate to susceptible. Genotypes were categorized according to the presence or absence of both antibiotic and tolerant characteristics. Genotypes (17%) exhibited both antibiosis against leaf feeding and tolerance for borer damage. Borer damage resulted in a 4% increase in grain yield of one genotype and a 50% increase in the number of heads of a second genotype. Tolerance and recovery resistance were the most important factors limiting yield loss in grain sorghum genotypes. In this study, the ability of sorghum for tillering (recovery resistance) was separated from the ability to produce heads on infested stems (tolerance). The importance of distinguishing between tolerance and recovery resistance in the evaluation of sorghum germplasm for borer resistance is emphasized.

The potential of plant genetics in the overall context of integrated pest control could be viewed simply as the potential of plant resistance in pest management. Genetic resistance in plants is one of the most effective and economic means of controlling plant pests. Resistant plants are the first line defence against pests. Successes in breeding for pest resistance depend upon the sound knowledge of the plant genes controlling resistance to pests.

Recent report on the existence of two nonatlelic and independent genes, Rac1 and Rac2 in cowpea cultivars ICV 10 and TVu 310, and ICV 11 and ICV 12, respectively, from the ICIPE has broadened the scope of cowpea breeding against aphid biotypes. Use of biotechnology as a plant breeding tool in transferring resistance genes into agronomically suitable cultivars appears to hold good promise for the future.

Several species of Chilo are serious pests (stem borers) of sorghum, maize, rice and sugar-cane. Studies on genetics of resistance to Chilo species have been carried out only In a few cases. In maize and sorghum resistance to C. partellus, measured in terms of leaf-feeding, dead hearts and stem-tunnelling is polygenic. Both additive and non-additive gene effects are important in the inheritance of resistance to C. partellus. However, the importance of additive and non-additive gene effects in determining resistance, varies with the resistance parameter in two crops. Resistance to leaf-feeding and stem-tunnelling is governed predominantly by additive genes, while both additive and non-additive genes are important in the inheritance of dead hearts. The non-additive gene action, however, is of higher magnitude and more important in the inheritance of resistance to dead hearts in maize than that in sorghum. Recurrent selection using S1, S2 lines would be efficient in increasing levels of resistance both in sorghum and maize. Tolerance should be considered as an important factor in sorghum breeding for borer resistance.

The level of resistance in rice to C. suppressalis is low to moderate and appears to be under polygenic control. A recurrent selection programme using male sterile lines could be effective in improving the level of resistance. No information is available on genetics of resistance to Chilo spp. in sugar-cane.

The spotted stem borer, Chilo partellus (Swinhoe) is an economically important pest in many sorghum growing areas of Asia and Africa. A chronological progress made in Indian and other programmes on natural and artificial screening techniques is reviewed. Numerous germpiasm accessions were evaluated and resistant sources identified and documented for various parameters of resistance such as foliar damage, “dead hearts” and stem tunnelling.

Studies on the mechanisms of resistance showed predominance of tolerance, variable degrees of antibiosis and antixenosis as only a factor for oviposition. The morphological characters and biochemical factors associated with resistance are discussed. The nature of resistance is polygenic and partially dominant over susceptibility. The inheritance patterns of resistance to foliar damage and/or “dead hearts”, and stem (stalk and peduncle) tunnelling damage are different and independent. Pedigree breeding with single and multiple crosses has been useful to transfer resistance in more economic background. Continuous screening for stem tunnelling over several generations improves the level of resistance. Recurrent selection was suggested alternatively with and without infestation for resistance and yield, respectively to increase the level of tolerance. The resistant sources utilized in developing commercially released high yielding varieties, hybrids and derivatives with low to moderate levels of resistance are listed. Efforts to develop cultivars with levels of resistance higher than presently grown cultivars and combining cross resistance to stem borers and shootfly are under way. Current progress has been reviewed and future strategies are suggested.

The midge, Contarinia sorghicola Coquillett, is a major pest of grain sorghum in many areas of Asia, Africa, Australia, Europe and America. Literature documenting the status of research on the biology, behaviour, and field and cage screening techniques is reviewed. Numerous germplasm entries have been evaluated and many resistant sources are identified from various midge screening programmes. A high degree of resistance was found in nine working groups viz., Caudatum, Durra, Caudatum/Nigricans-Zerazera, Caudatum/Kafir (Hegari), Nigricans, Caffrorum-Darso, Durra-Nigricans, Durra-Nandyal and Caudatum-Bicolor. The identified resistant sources and the midge resistant varieties released from the breeding programmes are listed. Studies on the mechanisms of resistance showed predominance of antixenosis for oviposition over adult attraction and variable degrees of antibiosis. The morphological characters and biochemical factors associated with resistance have been explored. Short and compact glumes which remain closed during anthesis conferred resistance. The tannin content in the ripening sorghum grain is related to resistance against the larva. The inheritance of resistance showed quantitative nature. The open and closed glume character expression indicated its dominance and recessiveness, respectively. Short glume character can be used as an useful genetic marker. Pedigree and modified pedigree breeding systems were suggested to transfer high level of midge resistance into agronomically acceptable types for selection and hybridization.

The shootfly, Atherigona soccata Rondani, is a major seedling pest of sorghum in many areas of tropical Asia, Africa and Mediterranean Europe. A chronological review of the progress made in various programmes on the screening techniques (natural and artificial) with artificial diets, sources, stability and mechanisms of resistance, bases (physico-morphological and biochemical factors) of resistance, inheritance and breeding for resistance is made. Many resistant varieties have been identified and sources of resistance utilized in breeding programmes to transfer resistance in high yielding background are listed. In addition, the glossy and trichome traits identified is sorghum cultivars are also reported. Glossy leaf surface and trichomes are frequently associated with shootfly resistance.

Insect pests are major yield reducers in sorghum under traditional farming practices in Africa. The use of resistant varieties in an integrated pest management scheme provides the most cost effective and practical means of sorghum insect control. Corneous grain sorghums are more weevil resistant than their softer endosperm counterparts. A wide range of sources of resistance to shootfiy, stem-borer and greenbug are known. Breeding for resistance to sorghum insects has been practised with varying degrees of success. Greenbug resistance breeding in sorghum has been successful in the U.S.A. Stem-borers are perhaps the most serious group of sorghum insects in Eastern Africa and further efforts are needed in breeding for resistance to these pests. In an effective pest resistance breeding work, the breeder and the entomologist must work as a team to make the fastest possible progress. Where several pests are of concern in an area, genotypes with multiple resistance in good agronomic backgrounds are needed.

A keen appreciation of the types and mechanisms of resistance must be attained in order to fully understand and utilize resistant cultivars as effective tools in today's pest management schemes. A historical account of plant resistance terminology is presented. Resistance can be classified as to intensities: immunity; high, moderate and low resistance; or types of resistance: vertical or horizontal resistance. The mechanisms of resistance include: non-preference, antibiosis and tolerance. Examples of the effects of both non-preference and antibiosis resistance on insect numbers are given.

Genetic variation of resistance and tolerance to stem-borer, Chilo partellus, was studied in three sorghum crosses. Parents, F1 and F2 progenies were evaluated for per cent foliar damage and stem tunnelling as a measure of resistance or susceptibility. The parental cultivars involved in the crosses represented a fairly distinct range of character expression for plant height, foliar damage, stem tunnelling, stem lodging and grain yield. Means, degrees of dominance in F1 and inbreeding depression in F2 suggested that susceptibility was dominant over resistance in crosses susceptible x resistant and susceptible × tolerant, while resistance was dominant over susceptibility in the cross tolerant × resistant. The variation patterns of foliar damage and stem tunnelling in parents, F1 and F2 progenies suggested that they are different and are independently inherited. Both resistance and tolerance mechanisms are operating in sorghum resistance to stem-borers and these mechanisms are independently inherited. Estimates of heritability (broad-sense), genetic coefficient of variation and expected genetic advance, indicated that the cross Serena (tolerant) x IS 2146 (resistant) provides maximum chances of selecting resistant and tolerant plants in the segregating populations. Recurrent selection (population breeding) is suggested to improve the level of stem-borer resistance and tolerance and yield in sorghum.