Metabolic origin of δ15N values in nitrogenous compounds from Brassica napus L. leaves

Nitrogen isotope composition (δ15N) in plant organic matter is currently used as a natural tracer of nitrogen acquisition efficiency. However, the δ15N value of whole leaf material does not properly reflect the way in which N is assimilated because isotope fractionations along metabolic reactions may cause substantial differences among leaf compounds. In other words, any change in metabolic composition or allocation pattern may cause undesirable variability in leaf δ15N. Here, we investigated the δ15N in different leaf fractions and individual metabolites from rapeseed (Brassica napus) leaves. We show that there were substantial differences in δ15N between nitrogenous compounds (up to 30 ) and the content in (15N enriched) nitrate had a clear influence on leaf δ15N. Using a simple steady-state model of day metabolism, we suggest that the δ15N value in major amino acids was mostly explained by isotope fractionation associated with isotope effects on enzyme-catalysed reactions in primary nitrogen metabolism. δ15N values were further influenced by light versus dark conditions and the probable occurrence of alternative biosynthetic pathways. We conclude that both biochemical pathways (that fractionate between isotopes) and nitrogen sources (used for amino acid production) should be considered when interpreting the δ15N value of leaf nitrogenous compounds

Transatlantic Influence in the Shaping of Business Education: The Origins of IMD, 1946-1990

The history of the International Institute for Management Development (IMD), one of the most prestigious business schools in the world, highlights the role of multinationals in establishing business education in Europe and the problem of legitimacy. The creation of IMD's predecessors CEI and IMEDE by Alcan and Nestlé also illuminates the role of Harvard Business School in their development and the reciprocal influences of American and European management education after World War II.

PEC1/AtABCG32 transport function in cuticle biosynthesis

Most aerial parts of the plants are covered by a hydrophobic coating called cuticle. The cuticle is formed of cutin, a complex mixture of esterified fatty acids that are embedded and associated with waxes. The cuticle often appears as a superposition of layers of different composition: The cuticle proper formed of cutin and a mixture of waxes and underneath, the cuticle layer containing cutin, intracuticular waxes and polysaccharides of the cell wall. In addition to its involvement in plant development by preventing organ fusions, the cuticle acts as a barrier to prevent water loss and protect plants against environmental aggressions such as excessive radiation or pathogens attacks. PEC1/AtABCG32 is an ABC transporter from the PDR family involved in cutin biosynthesis. Characterization of the peci mutant in Arabidopsis thaliana showed that PEC1 plays a significant role in the diffusion barrier formation in leaves and petals. The cuticles of leaves and flowers of peci are permeable and the cuticular layer rather than the cuticular proper was altered in the petals, underlining the importance of this particular layer in the maintenance of the diffusion barrier. Chemical analysis on the flower cutin monomer composition of ped mutant revealed a decrease in hydroxylated cutin monomers, suggesting a function of PEC1 in the incorporation of these monomers in the polymer cutin. However, the exact nature of the substrates of PEC1 remained elusive. PEC1 homologues in barley and rice, respectively HvABCG31/EIBI1 and OsABCG31, are also implicated in cuticle biosynthesis. Interestingly, the rice mutant displays more severe phenotypes such as dwarfism and spreading necrosis conducting to the seedling death. In this work, we further characterized osabcg31 mutant and hairpin-RNAi downregulated OsABCG31 plant lines showing reduced growth and cuticle permeability. Our analysis showed a decrease in hydroxylated cutin monomers and severe disruptions in the cuticle, which explain the permeability. Further insights into the function of the cuticle in rice resistance/susceptibility to Pathogens were obtained after inoculation with Magnaporthe oryzae, the fungus responsible for the rice blast disease. Osabcg31 as well as the transgenic lines downregulating OsABCG31 showed increased resistance to the fungus. However, only later steps of infection are reduced . and no impact is obseived on the germination or penetration stages, suggesting that the cuticle disruption per se is not responsible for the resistance. We further investigated the cause of the resistance by analyzing the expression of defense related gene in osabcg31 prior to infection. We found that osabcg31 constitutively express defense related genes, which may explain the resistance, the dwarfism and the cell death. osabcg31 is thus a tool to study the connection between cuticle, plant development and defense signaling networks in rice. The transport function of PEC1 family members is still unknown. In order to link cutin biosynthesis and transport activity, we combined ped mutation with mutations in cutin synthesis related genes. Here, we show that PEC1 acts independently from GPAT4 and GPAT8 pathway and partially overlaps with GPAT6 biosynthesis pathway that leads to the production of hydroxylated C16 cutin precursor 2-Mono(10,16-dihydroxyhexadecanoylJglycerol (2-MHG). In addition, we noticed that despite a comparable cutin monomer composition, ped mutant leaves cuticle are permeable while that of gpat6 mutant are not. This finding raises the possibility of PEC1 being required for the incorporation of C16 hydroxylated monomers and their structural arrangement rather than their direct transport towards the cuticle. A careful investigation of the cuticle permeability, cutin composition and ultrastructure during leave development in Wt plants and ped mutants revealed a possible different regulation of several pathways of cutin biosynthesis and showed the importance of PEC1 function early during leave cuticle maturation. In order to elucidate the transport activity of PEC1, we successfully expressed PEC1 in Nicotiana benthamiana plant system for direct transport experiments. This system will be used to test the PEC 1-dependent transport of potential substrates such as sn-2-monoacylglycerol loaded with a hydroxylated C16 fatty acid. -- Toutes les parties aériennes des plantes sont recouvertes d'une couche hydrophobe appelée «cuticule». Cette cuticule est composée de cutine, un polymère d'acides gras estérifiés, et de cires. La cuticule apparaît souvent sous forme de couches superposées: une première couche extérieure appelée «cuticle proper» formée de cutine et d'un mélange de cires, et une deuxième couche, la «cuticle layer», formée de cutine associée à des cires intracuticulaires et des polysaccharides pariétaux. La cuticule joue le rôle de barrière prévenant contre la perte d'eau et les agressions environnementales. AtABCG32/PEC1 est un transporteur ABC de la famille des PDR impliqué dans la synthèse de la cutine. L'étude du mutant peci d'Arabidopsis thaliana a révélé une fonction de PEC1 dans la formation de la barrière de diffusion. La cuticule des feuilles et fleurs de peci est perméable. Des altérations de la «cuticle layer» ont été démontrées, soulignant son importance dans le maintien de la barrière. L'analyse de la composition de la cutine de peci a montré une réduction spécifique en monomères hydroxylés, suggérant un rôle de PEC1 dans leur incorporation dans la cuticule. Cependant, la nature exacte des substrats de PEC1 n'a pas été identifiée. PEC1 possède deux homologues chez l'orge et le riz, respectivement HvABCG31 et OsABCG31, et qui sont impliqués dans la biosynthèse de la cuticule. Chez le riz, des phénotypes plus sévères ont été observés tels que nanisme et nécroses conduisant à la mort des jeunes plants. Dans cette étude, nous avons continué la caractérisation de osabcg31 ainsi que des lignées de riz sous exprimant le gène OsABCG31 et présentant une cuticule perméable tout en ayant une meilleure croissance. Notre étude a démontré une réduction des monomères hydroxylés de cutine et une désorganisation de la structure de la cuticule, aggravée dans le mutant osabcg31. Ce résultat explique la perméabilité observée. Des mformations P|us approfondies sur l'implication de la cuticule dans la résistance aux pathogènes ont été obtenues après inoculation du mutant osabcg31 et les lignées sous- exprimant OsABCG31 avec une souche virulente de Magnaporthe Oryzae, le champignon responsable de la pyriculariose du riz. Les différentes lignées testées ont démontré une résistance au pathogène. Cependant, seules les étapes tardives de l'infection sont réduites et aucun impact n'est observé sur la germination des spores ou la pénétration du champignon, suggérant que les modifications de la cuticule ne sont pas directement à l'origine de la résistance. L'analyse de l'expression de gènes impliqués dans la résistance à Magnaporthe.oryzae a mis en évidence l'expression constitutive de ces gènes en l'absence de tout contact avec le pathogène. Ceci explique la résistance, le nanisme et la mort cellulaire observés. Ainsi, osabcg31 représente un outil efficace pour l'étude intégrée des systèmes de régulation de la défense, de développement des plantes et la cuticule. La nature des substrats transportés par PEC1/AtABCG32 reste inconnue. Dans le but d'établir une liaison entre biosynthèse de cutine et transport des précurseurs par PEC1, la mutation peci a été combinée avec des mutants impliqués dans différentes voies de biosynthèse. Cette étude a démontré une fonction indépendante de PEC1 de la voie de biosynthèse impliquant les enzymes GPAT4 et GPAT8, et une fonction partiellement indépendante de la voie impliquant GPAT6 qui mène à la production de précurseurs sn-2- monoacylglycerol chargés en acides gras en C16 (2-MHG). De plus, malgré un profil similaire en monomères de cutine, gpat6 conserve une cuticule imperméable alors que celle de PEC1 est perméable. Ceci suggère que PEC1 est nécessaire à l'incorporation des monomères en C16 et leur arrangement structurel plutôt que simplement à leur transport direct. L'étude approfondie de la perméabilité cuticulaire, de la structure ainsi que de la composition en cutine pendant le développement des feuilles de peci et la plante sauvage a révélé l'existence de différentes régulations des voies de biosynthèses des monomères et a démontré l'importance de PEC1 dans les premières étapes de la mise en place de la cuticule. Pour identifier les substrats transportés, l'expression de PEC1 chez le système hétérologue Nicotiana benthamiana a été conduite avec succès. Ce système sera utilisé pour tester le transport de substrats potentiels tels que le sn-2-monoacylglycerol chargé en acide gras en C16.

El canto coral y las orquestas infantiles, una educación en valores = Choir singing and children’s orchestras, an education in values

This article looks at the musical activity carried out at Palafrugell Music School as a musical education centre over the past forty years. After giving a brief description of the work carried out there by vocal and instrumental groups, the article analyses and offers examples and tangible motives that use activities to show that forming part of a coral or instrumental group helps personal development and promotes the acquisition of habits, alongside musical training and learning. In short, an education in values

Cultural practices and genetic resistance as factors affecting soybean stem canker and plant yield in the Cerrado

Field experiments were conducted in the 1995-96 soybean (Glycine max) growing season to evaluate the effects of cultural practices and host genetic resistance on the intensity of soybean stem canker, caused by Diaporthe phaseolorum f.sp. meridionalis (Dpm). Experiments were conducted in a commercial field severely infected in the previous (1994-95) season. In one study, minimum tillage (MT) and no-tillage (NT) cropping systems were investigated for their effects on disease development and on plant yields in cvs. FT-Cristalina (susceptible) and FT-Seriema (moderately resistant). Another study evaluated the effects of plant densities (8, 15, 21 and 36 plants/m) on disease development in cvs. FT-Cristalina, FT-101 (moderately resistant) and FT-104 (resistant). Disease incidence and severity were consistently lower in NT than in MT, and plant yields were increased by 23% and 14% in the NT system for the susceptible and moderately resistant cultivars, respectively, compared to the yields in the MT system. The Gompertz and Logistic models described well the disease progress curves in all situations. For both susceptible and moderately resistant cultivars, disease severity increased proportionately to the increase in plant densities. At the end of the season, 100% of the plants of cv. FT-Cristalina were infected by Dpm, at all plant densities. Disease levels on cv. FT-101 were intermediate while only very low disease levels were recorded on cv. FT-104. There was a consistent negative correlation between stem canker severity and yield. Some practices demonstrated potential for direct application in disease control, and could be combined considering their additive effects.

Ammatillisen osaamisen tukeminen muuttuvissa toimintaympäristöissä : tutkimus ikääntyvien työntekijöiden näkökulmasta

The purpose of the study was to describe the experiences of received support of aging employees and their work related self-image in changing working environments. Firstly, theaim was to discover how the support from organisations and leaders was verified. Secondly, the aim was to get answers how employees experienced themselves as workers and as learners in the current work context. Thirdly, the aim was to compare different knowledge information stages and company cultures and how they have influenced the experiences of professional competence development among aging employees. In addition the education- and career backgrounds were investigated to gain more understanding of their role in experiencing support and relation to the occupational self-image. The theoretical frame of reference of this researchis multidisciplinary. The theoretical part focuses on the meaning of work for human being from a sociological, late-modern perspective. On the other hand it examines the ageing process from a physiological and also from a perspective of age discrimination and life control. The occupational selfimage and the strength of motivation has an effect on learning in working life which is crucial and firmpart individual trajectories. According to the theoretical review company culture, leadership and especially the managers' role as a creator of a learning atmosphere are increasingly critical for aging adults' learning when the role of informal work-based learning is increasing. The empirical data was collected with aquestionnaire and interviews, which were carried out in May to October 2001. The data consists of 263 respondents of which further eight persons were interviewed. All respondents were over the age of 45 and represented all levels of their organisations in an IT-technology firm and a chemical industry plant. The central findings in this research show that the aging adults have experienced that theemployers do care about the development of their occupational skills. On the other hand there are fewer concrete activities to reveal this support. There is anobvious disproportion between the expressed aims and the realisation of the activities. Signs of age discrimination are few. The style of management has becomemore supporting for self directed activities which are seen to support adults learning. Higher education and individual activity to seek possibilities to learnwere encouraging the development of occupational skills. Age itself was not a crucial aspect when comparing the experiences among younger (45-54 years) and older (55-64 years) groups. Job satisfaction and professional self esteem seemed tobe considerably strong. The individual characteristics were more important elements in developing occupational skills than the age. The degree of anxiety at work was low. In addition among the older group the strong feeling of coherence and the occupational self image were significant for supporting the professional competence. The motivation to learn was also stable. Among the seniors there was some slight evidence of declining motivation. In the IT-firm the support was experienced stronger for aging employees than in the chemical industry plant. Thosewho had experienced support in the chemical industry plant had higher educational background than the others. In IT-firm they also experienced more support from the manager than in the chemical industry plant. The results show that it is more likely that the differences are caused mostly by the stage of information intensity and the character of company culture which is determined by the activities. IT-business demands constantly accommodation to changes and the chemical industry plant which is representing more traditional business field, where the atmosphere of learning is determined by the traditions of company culture, the changes are carried out slowly.

Understanding and improving quality of secondary school education : conceptions among teachers in Tanzania

Temat för studien handlar om gymnasielärares uppfattningar om kvalitet och om hur kvalitet kan utvecklas i gymnasieutbildningen in Tanzania. Studien är till sin karaktär kvalitativ och består av utprövade semistrukturerade intervjuer med sammanlagt trettio lärare som arbetar i fyra gymnasieskolor både i urbana och rurala miljöer. Lärarna har varierande arbetserfarenhet och undervisar i olika ämnen. Huvudfokus har gällt identifieringen av variationer i lärares uppfattningar om kvalitet. På basen av två forskningsfrågor avslöjar analysen uppfattningar av hur lärare förstår och önskar utveckla kvaliteten på gymnasieutbildningen. Resultaten visar att lärare förstår kvaliteten på utbildningen i sina skolor som försök att möta skolans och samhällets mål, som individuella prestationer och förmågor som att inneha kompetenser och som att möta utmaningar inom utbildning, Identifierade uppfattningar var baserade på lärarnas personliga kunskap, arbetsmiljön och varierande omständigheter som rådde i deras skolor. Uppfattningar om en förbättring av kvaliteten i gymnasieutbildningen innefattade utveckling av lärares motivation, skolmiljön, arbetet i klassrum, kvaliteten på lärares kunskaper och färdigheter och undervisningsmaterial. Ambitionen bakom studien ar att erbjuda en plattform för strategier för att förbättra kvaliteten på gymnasieutbildningen. Resultaten strävar till att ge en fördjupad insikt i uppfattningar hos en utvald grupp av lärare som arbetar under samma villkor inom gymnasieskolor I Tanzania. Av den här anledningen är den genererade kunskapen därför relevant för att belysa lärares uppfattningar även utanför den studerade gruppen av respondenter.

Plant-Herbivore Interaction in a Fragmented Landscape: Local Adaptation and Inbreeding

Reciprocal selection between interacting species is a major driver of biodiversity at both the genetic and the species level. This reciprocal selection, or coevolution, has led to the diversification of two highly diverse and abundant groups of organisms, flowering plants and their insect herbivores. In heterogeneous environments, the outcome of coevolved species interactions is influenced by the surrounding community and/or the abiotic environment. The process of adaptation allows species to adapt to their local conditions and to local populations of interacting species. However, adaptation can be disrupted or slowed down by an absence of genetic variation or by increased inbreeding, together with the following inbreeding depression, both of which are common in small and isolated populations that occur in fragmented environments. I studied the interaction between a long-lived plant Vincetoxicum hirundinaria and its specialist herbivore Abrostola asclepiadis in the southwestern archipelago of Finland. I focused on mutual local adaptation of plants and herbivores, which is a demonstration of reciprocal selection between species, a prerequisite for coevolution. I then proceeded to investigate the processes that could potentially hamper local adaptation, or species interaction in general, when the population size is small. I did this by examining how inbreeding of both plants and herbivores affects traits that are important for interaction, as well as among-population variation in the effects of inbreeding. In addition to bi-parental inbreeding, in plants inbreeding can arise from self-fertilization which has important implications for mating system evolution. I found that local adaptation of the plant to its herbivores varied among populations. Local adaptation of the herbivore varied among populations and years, being weaker in populations that were most connected. Inbreeding caused inbreeding depression in both plants and herbivores. In some populations inbreeding depression in herbivore biomass was stronger in herbivores feeding on inbred plants than in those feeding on outbred ones. For plants it was the other way around: inbreeding depression in anti-herbivore resistance decreased when the herbivores were inbred. Underlying some of the among-population variation in the effects of inbreeding is variation in plant phenolic compounds. However, variation in the modification of phenolic compounds in the digestive tract of the herbivore did not explain the inbreeding depression in herbivore biomass. Finally, adult herbivores had a preference for outbred host plants for egg deposition, and herbivore inbreeding had a positive effect on egg survival when the eggs were exposed to predators and parasitoids. These results suggest that plants and herbivores indeed exert reciprocal selection, as demonstrated by the significant local adaptation of V. hirundinaria and A. asclepiadis to one another. The most significant cause of disruption of the local adaptation of herbivore populations was population connectivity, and thus probably gene flow. In plants local adaptation tended to increase with increasing genetic variation. Whether or not inbreeding depression occurred varied according to the life-history stage of the herbivore and/or the plant trait in question. In addition, the effects of inbreeding strongly depended on the population. Taken together, inbreeding modified plant-herbivore interactions at several different levels, and can thus affect the strength of reciprocal selection between species. Thus inbreeding has the potential to affect the outcome of coevolution.

eWOM communication in social media: A study of its antecedents in higher education context

The aim of this master’s thesis was to examine antecedents of eWOM communication in social media in the higher education context. In order to achieve this goal, eWOM communications of the students’ of international master’s programmes at Lappeenranta University of Technology were studied. The main research question was formulated as follows: What kind of effect do service-, brand-related antecedents, contextual antecedents and moderating factors have on LUT’s international master’s degree students’ eWOM communication in social media regarding their studies? The theory part of the master’s thesis was focused on the discussion of service- and brand related eWOM antecedents, contextual antecedents, as well as moderating relationships between them. The empirical part of the master’s thesis was based on quantitative research method. A web-based survey was carried out among current students of international master’s degree programmes at LUT. Out of 712 e-mail invitations sent, 159 responses were received in total. Thus, response rate was 22%. The results of the study showed that satisfaction, commitment, virtual brand community commitment, need for an advice, positive altruistic concerns, negative altruistic concerns, and attitude towards eWOM communications have an effect on eWOM in higher education context. Several moderating effects on eWOM were determined in the present study as well. On the other hand, it was found that dissatisfaction, loyalty, brand identification, desire to help the organization, need for positive self-enhancement, and social risk perception do not have an effect on eWOM in higher education context.

Impact of Word-of-Mouth on consumer decision-making: An information processing perspective in the context of a high-involvement service

This doctoral study conducts an empirical analysis of the impact of Word-of-Mouth (WOM) on marketing-relevant outcomes such as attitudes and consumer choice, during a high-involvement and complex service decision. Due to its importance to decisionmaking, WOM has attracted interest from academia and practitioners for decades. Consumers are known to discuss products and services with one another. These discussions help consumers to form an evaluative opinion, as WOM reduces perceived risk, simplifies complexity, and increases the confidence of consumers in decisionmaking. These discussions are also highly impactful as WOM is a trustworthy source of information, since it is independent from the company or brand. In responding to the calls for more research on what happens after WOM information is received, and how it affects marketing-relevant outcomes, this dissertation extends prior WOM literature by investigating how consumers process information in a highinvolvement service domain, in particular higher-education. Further, the dissertation studies how the form of WOM influences consumer choice. The research contributes to WOM and services marketing literature by developing and empirically testing a framework for information processing and studying the long-term effects of WOM. The results of the dissertation are presented in five research publications. The publications are based on longitudinal data. The research leads to the development of a proposed theoretical framework for the processing of WOM, based on theories from social psychology. The framework is specifically focused on service decisions, as it takes into account evaluation difficulty through the complex nature of choice criteria associated with service purchase decisions. Further, other gaps in current WOM literature are taken into account by, for example, examining how the source of WOM and service values affects the processing mechanism. The research also provides implications for managers aiming to trigger favorable WOM through marketing efforts, such as advertising and testimonials. The results provide suggestions on how to design these marketing efforts by taking into account the mechanism through which information is processed, or the form of social influence.

Changes in canola plant architecture and seed physiological quality in response to different sowing densities

The aim of this study was to evaluate changes in canola yield components and seed physiological quality in response to different sowing densities. The study was made in a greenhouse at the REIPESOL Company Technological Center, Madrid - Spain, with the commercial "Toccata" hybrid variety. The initial sowing density was 360,000 plants/ha and the plant population was later thinned down to include treatments of 250 and 180 thousand plants/ha. Harvested seeds were sent to the Seed Technology Center Laboratory (CATES) at the Madrid Polytechnic University (UPM) to evaluate changes in plant architecture and yield components, as well as the seed physiological quality of different plant parts. Results demonstrated that canola plants showed changes in morphology and yield components in response to different sowing densities. The population of 250,000 plants/ha showed the best seed yield demonstrating that maximum yield is directly related to a correct sowing density. The number of pods/plant was the most important component for increased seed yield/plant and seed yield/area. The spatial distribution of canola seeds in the plant and canola sowing density did not affect seed physiological quality.

Developmental patterns of individiuals within a sensory-based learning environment in art education : insights emerging from a case study /

My research permitted me to reexamine my recent evaluations of the Leaf Project given to the Foundation Year students during the fall semester of 1997. My personal description of the drawing curriculum formed part of the matrix of the Foundation Core Studies at the Ontario College of Art and Design. Research was based on the random selection of 1 8 students distributed over six of my teaching groups. The entire process included a representation of all grade levels. The intent of the research was to provide a pattern of alternative insights that could provide a more meaningful method of evaluation for visual learners in an art education setting. Visual methods of learning are indeed complex and involve the interplay of many sensory modalities of input. Using a qualitative method of research analysis, a series of queries were proposed into a structured matrix grid for seeking out possible and emerging patterns of learning. The grid provided for interrelated visual and linguistic analysis with emphasis in reflection and interconnectedness. Sensory-based modes of learning are currently being studied and discussed amongst educators as alternative approaches to learning. As patterns emerged from the research, it became apparent that a paradigm for evaluation would have to be a progressive profile of the learning that would take into account many of the different and evolving learning processes of the individual. A broader review of the student's entire development within the Foundation Year Program would have to have a shared evaluation through a cross section of representative faculty in the program. The results from the research were never intended to be conclusive. We realized from the start that sensory-based learning is a difficult process to evaluate from traditional standards used in education. The potential of such a process of inquiry permits the researcher to ask for a set of queries that might provide for a deeper form of evaluation unique to the students and their related learning environment. Only in this context can qualitative methods be used to profile their learning experiences in an expressive and meaningful manner.

Is GABA involved in regulating plant growth and development? /

Rapid and large accumulation of GABA (y-aminobutyric acid) in response to a number of plant stresses has been well documented. But the role(s) of GABA in plants is not well defined. In recent years, the possibility of GABA involvement in regulating plant growth and development has been raised. In the present study, this possibility was examined. First, to rapidly and accurately determine GABA levels in plant tissues, a spectrometric method for GABA determination was developed based on a commercially available enzyme Gabase. Seventy mM LaCb almost completely removed water-soluble pigments from plant tissues which greatly interfere with the absorbance reading at 340nm. Inactivation of GAD (glutamate decarboxylase) by immediately adding methanol to a frozen plant tissue powder was suggested to prevent GABA production during extraction. The recovery of GABA with this method was approximately 100%. Second, the relationship between GABA levels and hypocotyl elongation in soybean seedlings was analyzed using different approaches to regulate in vivo GABA levels and the elongation of hypocotyls. The following major observations were made. (1) Mechanical stimulation by stroking elevated GABA levels and concurrently induced a rapid and significant reduction in hypocotyl elongation. (2) External GABA was demonstrated to penetrate into the hypocotyls using '*C-GABA. Application of external GABA elevated in vivo GABA levels, but failed to inhibit hypocotyl elongation. (3) LaCla and blue light irradiation caused an inhibition in the elongation of dark-grown hypocotyls, whereas GABA levels were not significantly affected. (4) Ca^was suggested to be involved in the signal transduction pathway leading from mechanical stimulation to GABA production, as indicated by the ability of La'* to inhibit GABA production in stimulated hypocotyls. (5) Bicuculline, saclofen and baclofen (agonists and antagonists of GABA receptors in animals) had no effect on hypocotyl elongation. It might indicate that GABA-binding components which are structurally similar to animal GABA receptors and functionally capable of regulating plant growth may not exist in plants. Therefore, the conclusion was drawn that GABA alone is not sufficient to inhibit hypocotyl elongation. Third, chloride influx in isolated Asparagus cells was enhanced by lOmM GABA during a 3 hour incubation, but the effect was not specific for GABA. Chloride efflux was not influenced by GABA. Both influx and efflux of chloride were significantly inhibited by NPPB, a chloride channel blocker. These results suggest that GABA does not influence the activity of plant chloride channels.

Co-operative education and the development of self-esteem, an internal locus of control and work habits

This study compared approximately 50 grade 12 students studying In th~ co-operative education mode with approximately 50 grade 12 students studying in a traditional English course. Measures of self-esteem, locus of control and work habits were compared before and at the conclusion of one semester's involvement in the different programs. Using Coopersmith's Self-Esteem Inventory, the students who had chosen to study in the co-operative education mode scored significantly higher than the students in the traditional course. At the end of the semester, the co-operative education students' scores remained significantly higher than the English students'. Although the test showed no sjgnifi~ant changes in self-esteem. anecdotal reports indicated that co-operative education students had increased self-esteem over the semester. No significant differences in locus of control were observed between the two groups at any time. Significant differences in work habits were observed. While both groups had the same number of absences and the same marks before taking these courses, students who were involved in co-operative education had significantly fewer absences and significantly higher marks than the students studying in the traditional course. Anecdotal reports also indicated an improv~ment in work habits for students who had been involved in co-operative education. Recommendations of the study are for further research to determine more exactly how self-esteem and work habits develop in co-operative education students. Also. students. parents, teachers. and administrators need to be made aware of the success of this program.

Education in the halls : students' perspectives on cultural expression and resistance

This research is a qualitative study of cultural reproduction and resistance from students' perspectives. Thirteen teenagers (eight in attendance in regular high schools and five drop-outs) were recruited to take part and were involved to varying degrees through interviews, journal writing, and group interactive sessions. A purposive sampling design was used initially to recruit individuals known to the researcher through contacts in an alternate education setting. Other participants were recruited throughout the research phase. The theoretical aspects are premised on the work of Paul Willis, Michel Foucault, and Pierre Bourdieu. The reflexive praxeology of Bourdieu reflects the position taken as one way of understanding how students construct and respond to the situations of cultural dominance they experience in schools. The same reflexivity is offered for suggestions as to how teachers can respond to their own position in the education system.