Optimisation d'une plateforme web de divulgation scientifique: TheScienceBreaker

Ce travail est réalisé dans le cadre du projet TheScienceBreaker, plateforme de divulgation scientifique qui vise à favoriser la communication entre le monde académique et la population. Le site web, mise en place en début 2015, ne dispose pas des fonctionnalités ni d’une structure de l’information adéquates pour permettre la réalisation de sa mission. Ce travail de Bachelor consiste en la conception et la création d’un prototype qui représente le modèle « idéal » du site dont TheScienceBreaker devrait disposer pour atteindre à ces objectifs. Ainsi, le niveau d’utilisabilité du prototype a été évalué par le biais de deux séries de tests qui ont permis de mieux adapter le travail réalisé aux exigences des utilisateurs. Le modèle a été réalisé grâce au logiciel de prototypage « Axure RP », en appliquant les recommandations méthodologiques de plusieurs experts en utilisabilité et ergonomie web. Une première évaluation a été faite à travers un test en ligne qui demandait aux participants d’effectuer une sérié des tâches avec le prototype et de répondre à des questions : 26 personnes y ont participé et plusieurs problèmes d’utilisabilité ont été ainsi observés, analysés et enfin corrigés. En suivant une méthodologie d’amélioration progressive, le prototype a été soumis à une deuxième évaluation. La méthode utilisée pour cette série de tests a été le test utilisateur en présentiel : les 7 personnes qui y ont participé ont pu ainsi être observées directement pendant le déroulement des sessions de test. Ceci a permis de considérer des nouveaux paramètres d’observation qui ont mis en évidence d’autres problèmes d’utilisabilité et de vérifier la pertinence des améliorations apportées au modèle lors de la première évaluation. Une interprétation des problèmes révélés a permis de prioriser et appliquer les modifications nécessaires au prototype. Ainsi, sa version finale est le résultat d’un processus d’évaluation et d’optimisation progressif fondé sur des tests d’utilisabilité. Ce mémoire documente toutes les étapes du travail effectué : conception, prototypage, conception et réalisation des tests utilisateur, interprétation des résultats et améliorations au prototype. Des ultérieures améliorations feront l’objet des recommandations finales

Diversity and biomass accumulation in cultured phototrophic biofilms

In the present study, biomass development and changes in community composition of phototrophic biofilms grown under different controlled ambient conditions (light, temperature and flow) were examined. Source communities were taken from a wastewater treatment plant and used to inoculate growth surfaces in a semi-continuous-flow microcosm. We recorded biofilm growth curves in cultures over a period of 30 days across 12 experiments. Biovolume of phototrophs and community composition for taxonomic shifts were also obtained using light and electron microscopy. Species richness in the cultured biofilms was greatly reduced with respect to the natural samples, and diversity decreased even further during biofilm development. Diadesmis confervacea, Phormidium spp., Scenedesmus spp. and Synechocystis spp. were identified as key taxa in the microcosm. While a significant positive effect of irradiance on biofilm growth could be identified, impacts of temperature and flow rate on biofilm development and diversity were less evident. We discuss the hypothesis that biofilm development could have been subject to multistability, i.e. the existence of several possible stable biofilm configurations for the same set of environmental parameters; small variations in the species composition might have been sufficient to switch between these different configurations and thus have contributed to overwriting the original effects of temperature and flow velocity

Evaluation of behaviour of Lachancea thermotolerans biocontrol agents on grape fermentations

Previous researches have showed that Lachancea thermotolerans strains RCKT4 and RCKT5 inhibited the growth of Aspergillus. However, currently, there are no data on their nutritional preferences, as a possible substrate competitor against Saccharomyces cerevisiae, and their effects on fermentation. In this work, we observed that the biocontrol yeasts and S. cerevisiae BSc203, based on the utilization of 16 carbonate sources, revealed significant differences in the nutritional profile (biocontrol yeasts NS:0·25, BSc203 NS:0·56). Lachancea thermotolerans strains did not occupy the same niche as that of BSc203 (NOI:0·44). The biocontrol agents and BSc203 presented similar competitive attitude in terms of the sugar, ethanol and sulphite tolerances. During fermentation, the biocontrol yeasts were found to tolerate up to 12% v/v ethanol, 250 mg ml−1 of total SO2 and 30° Brix sugar. In mixed cultures, L. thermotolerans strains did not negatively affect the growth of BSc203 and the wine quality, except when RCKT4 was initially inoculated at a high proportion in the mixed culture 1MSK4 (1%BSc203/99%RCKT4), resulting in a lower production of CO2 and ethanol, in comparison with pure BSc203. RCKT5, at a high proportion, in 1MSK5 (1%BSc203/99%RCKT5) presented promising oenological properties. This fermentation showed lower acetic acid contents and higher total acidity than pure BSc203. Significance and Impact of the Study: Generally it is not evaluated if the biofungicide yeasts sprayed on vegetables alter the quality of the fermented products. This work focused on the importance of assessing the possible effects of yeast-based fungicides used in vineyards on grape fermentation, especially on Saccharomyces cerevisiae growth. In this context, the competition between biofungicide yeasts and S. cerevisiae under winemaking conditions is investigated.Fil: Nally, Maria Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; ArgentinaFil: Ponsone, Maria Lorena. Instituto Nacional de Tecnología Agropecuaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pesce, Virginia Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; ArgentinaFil: Toro, Maria Eugenia. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vazquez, Fabio. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Chulze, Sofia Noemi. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Time-delay estimation on identified model of a quadrotor UAV

LAUREA MAGISTRALEQuesto studio propone una selezione di metodi di identificazione, in tempo discreto, di ritardi di tempo implementati in ambiente MATLAB® con flessibilità sulla scelta del tempo di campionamento e adattati per l’uso con sistemi MIMO, come il modello di UAV adottato dal mio dipartimento e descritto nel primo capitolo di questa tesi. Il modello di UAV menzionato è illustrato con le ipotesi su cui si fonda, così come il pro cesso di identificatione usato per trovare i valori dei parametri del modello, questi risultati e il modello sono poi adattati all’ambiente MATLAB® in tempo discreto e formano il sis tema da cui sono estrapolati i dati necessari alla stima dei ritardi di tempo. Sono poi presentati quattro metodi, in particolare due legati alla massimizzazione della correlazione incrociata delle quantità in ingresso e in uscita: il metodo di thresholding, descritto da S. Björklund, e le funzioni criterio proposte in un articolo di J. Kekalainen; un altro metodo, di R. Waschburger e R. K. H. Galvão, è fondato sull’ottimizzazione ai minimi quadrati di una funzione di costo costruita a partire dalla dinamica degli stati del sistema; l’ultimo metodo, anche questo descritto da S. Björklund e chiamato oestruc, è costruito sulla stima di un modello output-error del sistema analizzato. Le loro basi teoriche sono spiegate e, in seguito, i metodi sono stati adattati all’ambiente MATLAB®. Ogni metodo è stato provato 90 volte, 30 per ciascun tipo di ingresso scelto, e per ciascuna dinamica (laterale, longitudinale, direzionale e verticale) del modello di UAV. I risultati sono stati paragonati tra loro e sono state tratte conclusioni sulle prestazioni di ogni metodo, illustrando per quali ingressi e casi d’uso ogni metodo è più adatto, quanto sono affidabili le loro stime e quanto tempo è stato impiegato per ricavare queste stime. Si è posta attenzione a confrontare le differenze tra l’applicazione di ogni metodo a un sistema stabile e a un sistema instabile.This study proposes a selection of discrete-time time delay identification methods imple mented in MATLAB® environment with a flexible choice of sample time and adapted to work with MIMO systems, such as the UAV model adopted by my department and described in the first chapter of this thesis. The aforementioned UAV model is illustrated with its underlying hypotheses, as is the identification process used to find the values of the model parameters, then the results and the model are adapted to the discrete-time MATLAB® environment, they form the system from which the data necessary to estimate the time delays are extracted. Four methods are then presented, specifically two related to the maximization of the cross correlation between input and output quantities: the thresholding method, as described by S. Björklund, and the criterion functions proposed in an article by J. Kekalainen; one founded on the least-squares minimization of a cost function built using the state dynamic of the system, by R. Waschburger and R. K. H. Galvão; the last, also described by S. Björklund and called oestruc, being built on the estimation of an output-error model of the analysed system. Their theoretical bases are explored and then they are adapted to the discrete-time MATLAB® environment. Each method has been tested for 90 times, 30 for each chosen input, on each dynamic (lateral, longitudinal, directional and vertical) of the UAV model. The results have been compared and conclusions regarding the performance of each method have been drawn, outlining which inputs and use cases each method is most suitable fir, how reliable their estimates are and how long they take to yield said estimates. Special attention has been paid to compare the difference in behaviour of each delay estimation method with a stable or with an unstable system

Use of fortified pied de cuve as an innovative method to start spontaneous alcoholic fermentation for red winemaking

Background and Aims: Some wineries, in order to promote the growth of yeasts able to ferment grape musts, traditionally produce wines using the ‘pied de cuve’ method. The aim of the present work was to study the performance of fortified pied de cuve (FPdC) prepared by addition of wine. Method and Results: Two FPdCs were prepared with the addition of wine at 1.5 and 3% (v/v) of ethanol to the musts and allowed to spontaneously ferment. The FPdCs were then added to fresh bulk musts in order to accelerate the spontaneous alcoholic fermentation (AF). Interestingly, several Saccharomyces cerevisiae strains isolated during the pied de cuve preparation were detected at the highest concentration throughout AF. The chemical composition of the wines conformed to commercial regulations. The volatile organic compounds (VOCs) were mainly represented by diethyl succinate and ethyl lactate, as well as by hexanol and isoamyl alcohol. Principal component analysis of the chemical parameters, VOCs and sensory data showed that the use of experimental pied de cuve influenced positively the composition of the final wines. Conclusion: The FPdC had no negative impact on the microbiological and chemical composition of wines, but it affected the diversity of the species S. cerevisiae present during AF and the sensory profile of the final wine. Significance of the Study: This study provided evidence that FPdC accelerates spontaneous AF and influences the sensory profile of red wines

The controversial relationship between chitosan and the microorganisms involved in the production of fermented beverages

Chitosan is a promising antimicrobial agent available in the beverage industry, because it ensures the control of a wide range of spoilage microorganisms. As chitosan does not alter the characteristics of fermented beverages, it is nowadays widely employed in the wine sector. In this work, an exhaustive chemical characterization of 12 commercial chitosans was performed in accordance with the OIV methods. These analyses made it possible to confirm or determine the animal or fungal origin of the 12 samples. Furthermore, ionic chromatography coupled with an amperometric detector (IC-PAD) confirmed peculiar polysaccharide profiles for fungal and animal-derived chitosans. The antimicrobial activity of chitosans was evaluated against the microorganisms involved in beverage fermentation or capable spoil wine, beer and cider. Chitosans were tested in static and stirred conditions, in a synthetic medium that reproduces fermented beverage conditions, to discriminate against the physical settling of cells and their specific antimicrobial activity. Moreover, the activity of the soluble portion of chitosan was checked by inoculating microorganisms in the media after chitosans removal. The results highlighted the different sensitivity of microorganisms to chitosans, allowing selective control of spoilage agents. However, the yeast and bacteria involved in fermentation were damaged by chitosan, and the synthetic media treated with this molecule showed a less fermentative aptitude. These results suggest that chitosan is a promising tool in fermented beverage production, but an in-depth study of the biochemical interaction between chitosan and food microorganisms is necessar

Microbiological and chemical monitoring of Marsala base wine obtained by spontaneous fermentation during large-scale production

The present work was undertaken to evaluate the effect of the natural winemaking on the microbial and chemical composition of Marsala base wine. To this purpose, a large-scale vinification process of Grillo grape cultivar was monitored from harvesting to the final product. Total yeasts (TY) showed a rapid increase after must pressing and reached values almost superimposable to those registered during the conventional winemakings. Lactic acid bacteria (LAB) were registered at the highest levels simultaneously to yeast growth at the beginning of the process. Saccharomyces cerevisiae was the species found at the highest concentrations in all samples analysed. Several strains (n= 16) was registered at high levels during the alcoholic fermentation and/or aging of wine; only two of them were detected on the grape surface. Lactobacillus plantarum was the LAB species most frequently isolated during the entire vinification process. Ethanol content was approximately 14% (v/v) at the end of vinification. The value of pH did not greatly vary during the process and the volatile acidity (VA) was detected at low concentrations during the entire transformation. The concentration of malic acid rapidly decreased during the AF; on the other hand, lactic acid showed an irregular trend during the entire process. trans-caffeil tartaric acid was the most abundant hydroxycinnamoyl tartaric acid and volatile organic compounds (VOC) were mainly represented by isoamylic alcohol and isobutanol

Il sommerso in Italia: analisi statistica del fenomeno dal 2011 al 2012

openT.DOR.14/15.

La posizione del vigneto non cambia il microbiota

I campioni di corteccia, foglie e grappoli isolati in 6 vigneti trentini con altitudini e forme di allevamento diverse non hanno presentato differenze dal punto di vista qualitativo nelle popolazioni microbiche rilevat