260 research outputs found
Phytochemical composition and antioxidant activity of Lavandula dentate extracts
Le but de ce travail consiste Ă Ă©tudier la composition des huiles essentielles et des polyphĂ©nols des racines, des tiges et des feuilles de la Lavande dentĂ©e et dâĂ©valuer leurs potentialitĂ©s antioxydantes. Lâanalyse et la quantification des huiles essentielles a montrĂ© que les feuilles sont les plus riches en huiles essentielles (0.89 mg/g MS) suivies par les tiges (0.68 mg/g MS) et enfin les racines (0,23 mg/g MS). Le constituant majeur de lâHE des racines est: le ÎČ-ocimĂšne. Dâautre part, le limonĂšne reprĂ©sente le composĂ© majeur de lâHE des tiges. Quant Ă lâHE des feuilles, elle est dominĂ©e par le camphre. Dâautre part, nos rĂ©sultats ont montrĂ© que les organes de la lavande montrent des teneurs en polyphĂ©nols totaux Ă©levĂ©es et variables selon lâorgane Ă©tudiĂ©. En effet, les extraits des racines sont caractĂ©risĂ©s par le contenu le plus Ă©levĂ© en polyphĂ©nols. Dâautre part, lâĂ©tude de lâactivitĂ© antioxydante des extraits des diffĂ©rents organes a indiquĂ© que les extraits de la racine sont particuliĂšrement les plus actifs et que leur analyse par RP-HPLC a montrĂ© que ces derniers sont riches essentiellement en acide rosmarinique. Finalement, les extraits de la Lavande dentĂ©e et particuliĂšrement ceux de la racine peuvent ĂȘtre considĂ©rĂ©s comme des sources alternatives dâantioxydants naturels puissants qui peuvent ĂȘtre utilisĂ©s en industrie agroalimentaire et pharmaceutique.In this study, Lavandula dentata organs (roots, stems and leaves) were investigated for their essential oils, total phenolics, flavonoids contents and antioxidant activities. Essential oil yields were 0.22% in roots, 0.68 % in stems and 0.89 % in flowers. Major components of the oils were ÎČ-ocimene, limonene and 1,8 cineol in roots, stems and leaves and flowers, respectively. In all organs, total phenolics content ranged from 42.57 to 16.17 mg gallic acid equivalents per gram of dry weight (mg GAE/g DW).The antioxidant activities of Lavandula dentata extracts obtained from the three organs were assessed using two tests (DPPH and reducing power). The root extract was strongly effective as DPPH radical scavenger and reducing agent. Thus, the identification of individual target polyphenolic compounds of roots was performed by RP-HPLC. The major phenolic compound detected in roots was rosmarinic acid. This activity was high enough for the plant to be a new and natural source of strongly antioxidant substances for use as natural additives in food and pharmaceutical industry
Attacks by a piercing-sucking insect (Myzus persicae Sultzer) or a chewing insect (Leptinotarsa decemlineata Say) on potato plants (Solanum tuberosum L.) induce differential changes in volatile compound release and oxylipin synthesis
Plant defensive strategies bring into play blends of compounds dependent on the type of attacker and coming from different synthesis pathways. Interest in the field is mainly focused on volatile organic compounds (VOCs) and jasmonic acid (JA). By contrast, little is known about the oxidized polyunsaturated fatty acids (PUFAs), such as PUFA-hydroperoxides, PUFA-hydroxides, or PUFA-ketones. PUFA-hydroperoxides and their derivatives might be involved in stress response and show antimicrobial activities. Hydroperoxides are also precursors of JA and some volatile compounds. In this paper, the differential biochemical response of a plant against insects with distinct feeding behaviours is characterized not only in terms of VOC signature and JA profile but also in terms of their precursors synthesized through the lipoxygenase (LOX)-pathway at the early stage of the plant response. For this purpose, two leading pests of potato with distinct feeding behaviours were used: the Colorado Potato Beetle (Leptinotarsa decemlineata Say), a chewing herbivore, and the Green Peach Aphid (Myzus persicae Sulzer), a piercing-sucking insect. The volatile signatures identified clearly differ in function with the feeding behaviour of the attacker and the aphid, which causes the smaller damages, triggers the emission of a higher number of volatiles. In addition, 9-LOX products, which are usually associated with defence against pathogens, were exclusively activated by aphid attack. Furthermore, a correlation between volatiles and JA accumulation and the evolution of their precursors was determined. Finally, the role of the insect itself on the plant response after insect infestation was highlighted
Origin of symbol-using systems: speech, but not sign, without the semantic urge
Natural languageâspoken and signedâis a multichannel phenomenon, involving facial and body expression, and voice and visual intonation that is often used in the service of a social urge to communicate meaning. Given that iconicity seems easier and less abstract than making arbitrary connections between sound and meaning, iconicity and gesture have often been invoked in the origin of language alongside the urge to convey meaning. To get a fresh perspective, we critically distinguish the origin of a system capable of evolution from the subsequent evolution that system becomes capable of. Human language arose on a substrate of a system already capable of Darwinian evolution; the genetically supported uniquely human ability to learn a language reflects a key contact point between Darwinian evolution and language. Though implemented in brains generated by DNA symbols coding for protein meaning, the second higher-level symbol-using system of language now operates in a world mostly decoupled from Darwinian evolutionary constraints. Examination of Darwinian evolution of vocal learning in other animals suggests that the initial fixation of a key prerequisite to language into the human genome may actually have required initially side-stepping not only iconicity, but the urge to mean itself. If sign languages came later, they would not have faced this constraint
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Re-Imagining Images of Organization: A Conversation With Gareth Morgan
In this article, we review the metaphors presented by Morgan in Images of Organization and highlight how they simultaneously act as ârelatively static reflectionsâ (i.e., they provide a history of organization theory) and ârelatively dynamic projectionsâ (i.e., stimulating the formulation of further organizational images). We also discuss the potential for new organizational metaphors and consider two specific metaphors (i.e., the âglobal brainâ and âorganization as mediaâ). We also challenge the established punctuated metaphorical process (i.e., a transfer from a metaphorical source domain to an organizational target domain), propose a dynamic perspective of interchange (i.e., source domain to target domain to source domain and so on), and develop the notion of multidirectionality (i.e., two-way projections between target and source domains)
The study of metaphor as part of Critical Discourse Analysis
This article discusses how the study of metaphoric and more generally, figurative language use contributes to critical discourse analysis (CDA). It shows how cognitive linguistsâ recognition of metaphor as a fundamental means of concept- and argument-building can add to CDA's account of meaning constitution in the social context. It then discusses discrepancies between the early model of conceptual metaphor theory and empirical data and argues that discursive-pragmatic factors as well as sociolinguistic variation have to be taken into account in order to make cognitive analyses more empirically and socially relevant. In conclusion, we sketch a modified cognitive approach informed by Relevance Theory within CDA
From Teamchef Arminius to Hermann Junior: glocalised discourse about a national foundation myth
If for much of the nineteenth and twentieth centuries, the âBattle of the Teutoburg Forestâ, fought in 9 CE between Roman armies and Germanic tribes, was predominantly a reference point for nationalist and chauvinist discourses in Germany, the first decade of the twenty-first century has seen attempts to link public remembrance with local/regional identities on the one hand and international/intercultural contact on the other. In the run up to and during the âanniversary yearâ of 2009, German media, sports institutions and various other official institutions articulating tourist, economic and political interests attempted to create a new âglocalisedâ version of the public memory of the Teutoburg battle. Combining methods of Cognitive Linguistics and Critical Discourse Analysis, the paper analyses the narrative and argumentative topoi employed in this re-orientation of public memory, with a special emphasis on hybrid, post-national identity-construction. Das zweitausendjĂ€hrige Gedenkjahr der âSchlacht im Teutoburger Waldâ im Jahr 2009 bot eine gĂŒnstige Gelegenheit, die bis in die zweite HĂ€lfte des 20. Jahrhunderts dominante Tradition nationalistischâchauvinistischer Deutungen des Sieges von germanischen StĂ€mmen ĂŒber drei römische Legionen zu korrigieren und zu ĂŒberwinden. Der Aufsatz analysiert mit Hilfe diskurslinguistischer Methoden die Anstrengungen regionaler Institutionen und Medien, die nationale Vereinnahmung des historischen Gedenkens kritisch zu thematisieren sowie neue, zum eine lokal situierte, zum andern international orientierte Identifikationsangebote anzubieten. Die Analyse zeigt, dass solche âde-nationalisiertenâ Identifikationsangebote zwar teilweise auch frĂŒher verwendet wurden, aber heutzutage rekontextualisiert und auf innovative Weise in den Vordergrund gestellt werden
Visualizing Sound, Hearing Diagrams: On the Creative Process of Syrmos by Iannis Xenakis
A salient feature of Iannis Xenakisâ compositional practices was the use of several concepts and techniques borrowed from architectural design and from scientific fields. He sometimes drew complete graphic scores preluding the transcription of his fair copy of conventional musical notation. I discuss the diagrammatical features of Xenakisâ graphic score for Syrmos: although disparate representations depend on shared image schemata and cross-modal correspondences, their respective compositional logics are dissimilar
European spaces and the Roma: Denaturalizing the naturalized in online reader comments
With the entry of several Eastern European nations into the European Union (EU), a âthirdâ space has developed in the discourse for nations perceived as not fully integrated âinsideâ the EU system. This article investigates the construction of this âthird spaceâ in the resultant âmoral panicâ about undesired immigration from other EU countries and its potential drain on the social services of the United Kingdom and links it to Euroskeptic discourse in British media. The article uses construal operations from cognitive linguistics combined with critical discourse studies as a way of denaturalizing the discourse in online comments that focus on the Bulgarian/Romanian immigration issue which we then connect to anti-Roma discourse. Results reveal a view of the United Kingdom as contaminated by Roma and underscore the need for novel metaphors to be countered before they become entrenched and used as tools for political propaganda
Can sensory boar taint levels be explained by fatty acid composition and emitted volatile organic compounds in addition to androstenone and skatole content?
peer reviewedThis study aimed at understanding which molecules were responsible for the differences existing in
boar taint sensory evaluation. The latter was therefore linked to the results of skatole and
androstenone chemical analyses, fatty acid composition and VOC profiles of heated backfat. This
study confirmed that some discrepancy exists between chemical analysis and sensory evaluation of
tainted backfats. Significant correlations between human nose scores and fatty acid composition were
not revealed. Strong correlations between emissions and contents in skatole and androstenone were
found. Oxidation products of polyunsaturated fatty acids, with fatty odor descriptors, were found to be
more present in the VOC profiles of boar fat considered untainted through the human nose
methodology. Weak coefficient of determination for partial least square regression indicates that other
factors, yet unknown, are responsible for sensory evaluation outcomes. These findings hence support
the idea that high human nose score is mainly due to boar taint compounds rather than general
differences in VOC profiles.
Keywords: boar taint, androstenone, skatole, human nose, fatty acid, VO
Using resource graphs to represent conceptual change
We introduce resource graphs, a representation of linked ideas used when
reasoning about specific contexts in physics. Our model is consistent with
previous descriptions of resources and coordination classes. It can represent
mesoscopic scales that are neither knowledge-in-pieces or large-scale concepts.
We use resource graphs to describe several forms of conceptual change:
incremental, cascade, wholesale, and dual construction. For each, we give
evidence from the physics education research literature to show examples of
each form of conceptual change. Where possible, we compare our representation
to models used by other researchers. Building on our representation, we
introduce a new form of conceptual change, differentiation, and suggest several
experimental studies that would help understand the differences between
reform-based curricula.Comment: 27 pages, 14 figures, no tables. Submitted for publication to the
Physical Review Special Topics Physics Education Research on March 8, 200
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