The Control Of Zealactone Biosynthesis And Exudation Is Involved In The Response To Nitrogen In Maize Root.

Nitrate acts as a signal in regulating plant development in response to environment. In particular nitric oxide (NO), auxin and strigolactones (SLs) were supposed to cooperate to regulate the maize root response to this anion. In this study, a combined approach based on LC-MS/MS and on physiological and molecular analyses was adopted to specify the involvement of SLs in the maize response to N. Our results showed that N deficiency strongly induces SL exudation, likely through stimulating their biosynthesis. Nitrate provision early counteracts and also ammonium lowers SL exudation, but less markedly. Exudates obtained from N-starved and ammonium-provided seedlings stimulated Phelipanche germination, whereas when seeds were treated with exudates harvested from nitrate-provided plants no germination was observed. Furthermore, our findings support the idea that the inhibition of SL production observed in response to nitrate and ammonium would contribute to the regulation of lateral root development. Moreover, the transcriptional regulation of a gene encoding a putative maize WBC transporter, in response to various nitrogen supplies, together with its mRNA tissue localization, supported its role in SL allocation. Our results highlight the dual role of SLs as molecules able to signal outwards a nutritional need and as endogenous regulators of root architecture adjustments to N, thus synchronizing plant growth with nitrogen acquisitio

The structuration of brain dominance on organizational communication : a correlational study

The purpose of this study was to examine if the influence of brain dominance as defined by Herrmann (1982, 1995), which includes left-brain/right-brain dominance and cerebral/ limbic dominance, offers predictive capabilities in determining preferences for communication channel selection, feedback frequency, and job satisfaction in organizations. The study also examined whether sex has a determining role in predicting preferences for communication channels, feedback, and job satisfaction. Raw scores from the Herrmann Brain Dominance Instrument (HBDI) were correlated with responses to a validated survey instrument, which combined items from the International Communication Association (ICA) Audit (Downs, 1988), and the Communication Satisfaction Questionnaire (CSQ) (Downs & Hazen, 1977). Participants were volunteers from four separate organizations who had taken the HBDI as part of a series of workshop seminars on whole brain thinking. Of the 210 participants, 108 were male and 102 were female. Insights into communication patterns in organizations were provided by Structuration Theory (Giddens, 1984), which proposes that social systems are produced and reproduced through daily communication interaction. The patterns that arise from the contradictions and tensions of daily interaction across time and space become real to us as institutions or organizations. Eleven hypotheses were tested using pairwise comparisons. Three hypotheses were rejected outright: (1) Males prefer left-brain communication channels; (2) Females prefer right-brain channels; (3) Individuals who are multi-dominant (strong preference for more than one type of thinking) are more satisfied with communication than single or double-dominant individuals. One explanation for the rejection of these hypotheses is that the female sample was significantly different than the general population of females. Partial support was registered for the other 8 hypotheses, indicating that brain dominance does influence communication channel preference and feedback. Unexpected results showed an uncanny consensus for certain communication channel preferences across all four quadrants of the brain, and consensus against certain communication channels-for all four organizations. These striking results indicated strong support for the effect of structuration in organizational communication. In essence, the power of structuration trumps the influence of brain dominance in organizations. Future studies will include a sample that is more left-brain/right-brain balanced (i.e. subjects will be chosen from a wide variety of professions, not just business) and the development of an independent survey instrument designed to more accurately measure the influence of brain dominance on communication preferences

Etude de l'activité antivirale d'extraits d'Euphorbia de Corse : recherche de nouveaux diterpènes d'intérêt biologique

Chikungunya fever is caused by an arthropod-borne virus that is associated with massive epidemics and severe morbidity (virus-induced arthralgia, fever, myalgia and rashes). Worldwide expansion of the mosquito vectors, such as Aedes albopictus ("Tiger moquito) is responsible for the spread of Chikungunya virus (CHIKV) throughout the world. A. albopictus has spread throughout Mediterranean areas, which could lead to epidemics outbreaks. Currently, no antiviral drugs or vaccines are available for the treatment or prevention of CHIKV infection. Since ten years, however, recent results showed that diterpene esters from Trignostemon (Euphorbiaceae) possess inhibiting activity of CHIKV replication.With the objective to discover new compounds with antiviral activities, 45 extracts from various plant parts of 11 Euphorbiaceae species native to Corsica were evaluated for selective inhibition of CHIKV replication. In collaboration with Dr. Leyssen (KU Leuven, Belgium), several extracts made from 10 Euphorbia species exhibited significant and selective anti-CHIKV activity in a virus-cell-based assay. The antiviral activities of 29 commercially available phorboïds were studied. Some phorboïds were potent inhibitors of CHIKV and human immunodeficiency virus (VIH) replication. Results allowed drawing new structure-activity relationships, which supported the hypothesis that PKC may be an important target in CHIKV replication. In order to confirm or infirm the presence of phorboïds with anti-CHIKV activity in Euphorbia extracts, a liquid chromatography (LC) coupled to linear ion trap mass spectrometry (MSn) method was developed using standard compounds. Application of this methodology indicated that none anti-CHIKV phorboïds was present in Euphorbia extracts. A second LC-MSn procedure was developed to profile untargeted phorboïdes. Results suggested that numerous other diterpene esters were present in the Euphorbia extracts. The species Euphorbia amygdaloides ssp. semiperfoliata was selected to perform a bioassay-guided purification procedure, which led to the isolation and identification of 14 jatrophane esters, including eight new components. Among them, antiviral evaluation indicated that one jatrophane ester was possessing anti-CHIKV and anti-HIV activities. Furthermore, the structure of an atypical jatrophane ester derivative, jatrohemiketal, was determined unambiguously through an original strategy combining NMR spectroscopy and molecular modeling. Finally, an original tandem mass spectrometry (MS/MS)-targeted supercritical fluid chromatography (SFC) method was developed and used to study bioactive fractions of E. amygdaloïdes ssp. semiperfoliata. The MS/MS data were analyzed by molecular networking. Thanks to this approach, four 4-deoxyphorbol esters and two new jatrophane esters were targeted, isolated and identified. Collaboration with the group of Pr. Alcami (CNM, Espagne) was started to explore the anti-HIV properties of the isolated diterpene esters. Thus, one compound derived from 4-deoxyphorbol esters proved to possess a potent inhibiting activity of HIV-1 replication (IC50 = 8 nM, and selectivity index > 6250). The investigation of the mechanism of this component indicated that it acted like prostratin, but with antiviral effect more than 28-fold. Furthermore, the evaluation of the anti-CHIKV activity indicated that another 4-deoxyphorbol derivative was one of the strongest inhibitor of CHIKV replication isolated up to date (EC50 = 0.34 ± 0.12 µM and selectivity index > 638).Le chikungunya est une maladie transmise par des moustiques du genre Aedes (dont A. albopictus, dit "moustique tigre"). Cette maladie provoque d'intenses fièvres et des douleurs articulaires chroniques fortement invalidantes. Les moustiques potentiellement vecteurs du virus du chikungunya (CHIKV) sont des espèces invasives qui, à la faveur du réchauffement climatique, se sont récemment implantés dans plusieurs régions du monde, dont la région méditerranéenne. Sa présence constitue un terreau favorable à la survenue d'épidémie. A l'heure actuelle, il n'existe ni vaccin, ni traitement médicamenteux efficace. Toutefois, des articles scientifiques ont récemment rapporté que des esters de diterpène isolés du genre Trigonostemon (Euphorbiaceae), avaient une activité inhibitrice de la réplication du CHIKV.Dans le cadre de ces travaux de thèse, des extraits de plantes du genre Euphorbia de Corse ont été étudiés dans le but d'isoler de nouvelles molécules douées d'activité antivirale sur la réplication du CHIKV. En collaboration avec le Dr. P. Leyssen (KU Leuven, Belgique), l'évaluation de l'activité anti-CHIKV de 45 extraits, obtenus à partir de 11 Euphorbiaceae de Corse, a permis de mettre en évidence la forte activité inhibitrice et sélective de des extraits d'espèces du genre Euphorbia in cellulo. L'activité antivirale d'une série de 27 diterpènes de type phorboïde, disponibles commercialement, a également été étudiée. Les résultats ont montré que certains dérivés avaient une forte activité inhibitrice de la réplication du CHIKV, mais aussi sur celle du virus de l'immunodéficience humaine (VIH). Ces études ont permis d'une part, de déduire des relations structure-activité inédites et d'autre part, de soutenir l'hypothèse d'un mécanisme d'action anti-CHIKV impliquant la modulation des protéines kinases C (PKCs) par les phorboïdes. Dans le but de confirmer ou d'infirmer la présence des phorboïdes dans les extraits d'Euphorbia, une première méthode utilisant la chromatographie liquide (LC) haute performance couplée à un spectromètre de masse à trappe d'ions (MSn), a été développée à partir des composés standards. L'application de cette méthodologie a révélé qu'aucun des phorboïdes ciblés n'était présent dans les extraits d'Euphorbia. Ainsi, une seconde procédure LC-MSn a été mise en œuvre afin de détecter - de manière non ciblée - différents types d’esters diterpéniques. L'utilisation de cette approche a révélé que de nombreux diterpènes, non-apparentés aux phorboïdes, étaient présents dans les extraits. Un extrait de l'espèce Euphorbia amygdaloides subsp. semiperfoliata a été sélectionné pour réaliser un fractionnement bio-guidé, aboutissant à l'isolement et l'identification de 14 esters de jatrophane, dont neuf nouveaux composés. Parmi eux, l'un s'est avéré inhiber la réplication du CHIKV et du VIH. Par ailleurs, la structure d'un ester de jatrophane atypique, le jatrohémicétal, a été élucidée grâce à une approche originale combinant modélisation moléculaire et spectroscopie par résonance magnétique nucléaire (RMN). Enfin, une nouvelle procédure de purification ciblée par spectrométrie de masse tandem (MS/MS) en chromatographie en phase fluide supercritique (SFC) a été développée et appliquée sur des fractions bioactives d'E. amygdaloïdes subsp. semiperfoliata. L’interprétation des données MS/MS s’est appuyée sur la génération de réseaux moléculaires. Par cette méthodologie, quatre nouvelles molécules ont pu être détectées, purifiées et identifiées ; il s’agit de deux nouveaux esters de jatrophane et de quatre esters dérivés du 4-déoxyphorbol. L'activité anti-VIH des constituants isolés a également pu être explorée dans le cadre d’une collaboration avec l'équipe du Pr. Alcami (CNM, Espagne). Ainsi, l’un des esters de 4-deoxyphorbol s’est révélé être doué d'un exceptionnel pouvoir inhibiteur de la réplication du VIH-1 (IC50 = 8 nM et index de sélectivité > 6250). Son mécanisme d'action semble s'apparenter à celui de la prostratine (molécule antivirale de référence) mais avec des propriétés antivirales environ 28 fois supérieur. Un deuxième ester de 4-déoxyphorbol s’est avéré être un des plus puissants inhibiteurs du CHIKV isolé à ce jour (EC50 = 0,34 ± 0,12 µM and SI > 638). Mots clés : Euphorbia, activité antivirale, chikungunya, diterpène, spectrométrie de mass

Context aware advertising

IP Television (IPTV) has created a new arena for digital advertising that has not been explored to its full potential yet. IPTV allows users to retrieve on demand content and recommended content; however, very limited research has been applied in the domain of advertising in IPTV systems. The diversity of the field led to a lot of mature efforts in the fields of content recommendation and mobile advertising. The introduction of IPTV and smart devices led to the ability to gather more context information that was not subject of study before. This research attempts at studying the different contextual parameters, how to enrich the advertising context to tailor better ads for users, devising a recommendation engine that utilizes the new context, building a prototype to prove the viability of the system and evaluating it on different quality of service and quality of experience measures. To tackle this problem, a review of the state of the art in the field of context-aware advertising as well as the related field of context-aware multimedia have been studied. The intent was to come up with the most relevant contextual parameters that can possibly yield a higher percentage precision for recommending advertisements to users. Subsequently, a prototype application was also developed to validate the feasibility and viability of the approach. The prototype gathers contextual information related to the number of viewers, their age, genders, viewing angles as well as their emotions. The gathered context is then dispatched to a web service which generates advertisement recommendations and sends them back to the user. A scheduler was also implemented to identify the most suitable time to push advertisements to users based on their attention span. To achieve our contributions, a corpus of 421 ads was gathered and processed for streaming. The advertisements were displayed in reality during the holy month of Ramadan, 2016. A data gathering application was developed where sample users were presented with 10 random ads and asked to rate and evaluate the advertisements according to a predetermined criteria. The gathered data was used for training the recommendation engine and computing the latent context-item preferences. This also served to identify the performance of a system that randomly sends advertisements to users. The resulting performance is used as a benchmark to compare our results against. When it comes to the recommendation engine itself, several implementation options were considered that pertain to the methodology to create a vector representation of an advertisement as well as the metric to use to measure the similarity between two advertisement vectors. The goal is to find a representation of advertisements that circumvents the cold start problem and the best similarity measure to use with the different vectorization techniques. A set of experiments have been designed and executed to identify the right vectorization methodology and similarity measure to apply in this problem domain. To evaluate the overall performance of the system, several experiments were designed and executed that cover different quality aspects of the system such as quality of service, quality of experience and quality of context. All three aspects have been measured and our results show that our recommendation engine exhibits a significant improvement over other mechanisms of pushing ads to users that are employed in currently existing systems. The other mechanisms placed in comparison are the random ad generation and targeted ad generation. Targeted ads mechanism relies on demographic information of the viewer with disregard to his/her historical consumption. Our system showed a precision percentage of 69.70% which means that roughly 7 out of 10 recommended ads are actually liked and viewed to the end by the viewer. The practice of randomly generating ads yields a result of 41.11% precision which means that only 4 out of 10 recommended ads are actually liked by viewers. The targeted ads system resulted in 51.39% precision. Our results show that a significant improvement can be introduced when employing context within a recommendation engine. When introducing emotion context, our results show a significant improvement in case the user’s emotion is happiness; however, it showed a degradation of performance when the user’s emotion is sadness. When considering all emotions, the overall results did not show a significant improvement. It is worth noting though that ads recommended based on detected emotions using our systems proved to always be relevant to the user\u27s current mood

MAINSTREAM MEDIA COVERAGE (UK) OF ESPORTS TOURNAMENT THE ‘EPREMIER LEAGUE’ FINALS 2019 AND 2021. A MIXED-METHODS STUDY.

This study investigates the factors limiting mainstream media coverage of esports in the UK, specifically focusing on EA Sports' FIFA Series. The research aims to assess the current landscape of esports journalism, mainstream media perception, familiarity with the term 'esports', content categorisation, coverage extent, live event viewership, and potential barriers and opportunities for increased exposure. Despite the growing academic interest in esports, there is a noticeable gap in research regarding mainstream media coverage of esports in UK newspaper and broadcast journalism and of esports journalism. This project's critical analysis therefore of esports journalism offers a timely and original contribution to understanding the relationship between mainstream UK media and the niche esports broadcast/ journalism sector, and the factors influencing the sector’s limited exposure. Employing a mixed-methods approach, this study combines quantitative and qualitative data collection methods such as surveys, content analysis, and interviews. Focusing on mainstream media coverage of esports, the research utilises Rogers' Diffusion of Innovation Theory (2003) and Tidd and Bessant’s 4Ps of Innovation Model (2021) to explore the potential for esports to become a sustainable sector in the UK's digital economy. The study concentrates on the UK tournament the 'ePremier League' 2019 and 2021 and its reception by UK mainstream media, examining the relationship between traditional and new media platforms. The findings reveal a lack of significant value for esports in UK mainstream media, distrust of mainstream media within the esports sector, and a discrepancy in the categorisation of esports content between mainstream and esports media. This study highlights the need for independent investigative reporting and improved understanding of the esports sector within mainstream media to foster its growth and acceptance. The results hold considerable significance for various stakeholders, including publishers, policymakers, and analysts. For instance, the National Union of Journalists and the British Association of Journalists will find the insights on current journalistic practices valuable. Educational organisations such as the National Training Council of Journalists will appreciate findings regarding the importance of professional training for journalists. Likewise, mainstream broadcasters and esports media, including SKY Sports and Gfinity, will be interested in findings related to live streaming and broadcasting live esports events

Human-Machine Communication: Complete Volume. Volume 2

This is the complete volume of HMC Volume 2